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1

Malave, Carmen. "Deep hole drilling - Cutting forces and balance of tools." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-20696.

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Drilling is a standard process for producing holes in metal materials. With an increased hole depth the demands increase on both machine and tool. Deep hole drilling is a complex process which ischaracterized by a high metal removal rate and hole accuracy. A hole deeper than ten times the diameter can be considered a deep hole which requires a specialized drilling technique. During adeep hole drilling process, the forces generated on the deep hole drill give a rise to a resultant radial force. The resultant radial force pushes the drill in a radial direction during a drilling operation. The radial force direction is of crucial importance in regard of tool guidance, stability and hole size accuracy. This force affects tool performance, reduces tool life and has an impact on the bore surface. Due to the complex nature of deep hole drilling, Sandvik Coromant wishes to get a better understanding of how their current deep hole drilling tools are balanced. The purpose of this study is to conduct a survey of a number of drills of Sandvik Coromant deep hole drill assortment. The main aim of this study is to calculate and measure the resultant radial force generated during a deep hole drilling operation. The forces are calculated with the aid of a calculation program and test-runs on a number of drills. This report presents the calculated magnitude and direction of the resultant radial force duringentrance, full intersection and at the exit of the workpiece. In addition to the measured values of theresultant radial force during entry and full intersection. Four different drill geometries are evaluated which of two are competitor drills. A deep hole drill geometry is re-modified in aspect to drill stability based on the outcome of the measured and calculated results. The results acquired from the performed calculation and measurements of the resultant showed that the resultant radial force acts in an angular direction that was outside the range between the support pads. This true for three of the four evaluated drill geometries. There were minor differences between the measured and calculated forces which enforce the reliability of the used calculation program. The modified drill geometry of a deep hole drill gave an indication of which geometry variables have impact on the resultant radial force magnitude and angular direction. The data presented in this report can be a base for future development of a deep hole drill toolgeometry in regard to the resultant radial force. Variables affecting the calculated results and theresultant radial force are presented and discussed. The study is concluded with suggestions of futurework based on the acquired data.
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2

Balan, Anil. "Theoretical and experimental investigations on radial electromagnetic forces in relation to vibration problems of induction machines." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24067.pdf.

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3

Ігнатьєва, П. І., Олександр Іванович Котенко, Александр Иванович Котенко та Oleksandr Ivanovych Kotenko. "Радіальні сили, що діють на роторвільновихрового насоса". Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/40381.

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Проточна частина вільновихрового насоса (СВН) виконана так, що робоче колесо (РК) знаходиться в циліндричній розточці корпусу в стороні від основного потоку, а перед робочим колесом утворена вільна камера, через яку проходить основна частина потоку рідини. Повна симетрія розташування РК в циліндричній розточці корпусу призводить до рівномірного розподілу тиску в зазорі між торцями лопатей по зовнішньому діаметру і внутрішнім діаметром циліндричної розточки. Тому, таке конструктивне виконання має виключити існування радіальної сили.
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4

Bouba, Oumarou. "Théories quantique et semi-classique des intégrales radiales de transitions dipolaires et multipolaires des états excités : Applications au calcul des forces d'oscillateur et des probabilités de transition dans l'approximation à une configuration." Orléans, 1986. http://www.theses.fr/1986ORLE0010.

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Calcul des intégrales radiales à l'approximation quasi classique (JWKB) des fonctions d'onde radiales, complétée par une description en termes de trajectoires elliptiques de l'électron optique. Obtention d'expressions analytiques de ces intégrales dont on simplifie le calcul à l'aide d'une méthode basée sur le développement limite d'une fonction bien adaptée à des calculs par interpolation ou extrapolation : elles s'expriment toutes en termes de deux fonctions fondamentales qui ne dépendent que de la différence entre deux nombres quantiques principaux effectifs des états initial et final. Déduction de forces d'oscillateur et probabilités de transition aussi précises que celles obtenues par quantique.
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5

Chitroju, Rathna. "Improved performance characteristics of induction machines with non-skewed symmetrical rotor slots." Licentiate thesis, KTH, School of Electrical Engineering (EES), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11510.

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<p>Induction machines convert more than 55% of electrical energy into various other forms in industrial and domestic environments. Improved performance, especially by reduction of losses in induction machines hence can significantly reduce consumption of electricity. Many design and control methods are adopted to make induction machines work more efficiently, however certain design compromises are inevitable, such as skewing the rotor to improve the magnetic noise and torque characteristics increase the cross current losses considerably in a cage rotor, degrading the efficiency of the motor. Crosscurrent losses are the dominating stray losses which are dependent on several factors among them are percentage skew and the contact resistance between the rotor bars and laminations. It is shown in this thesis that implementing a design change which has non-skewed asymmetrical distribution of rotor slots can serve the same purpose as skewing i.e., reduction of the magnetic noise, thereby avoiding the negative effects of skewing the rotor slots especially by reducing the cross-current losses.</p><p>Two design ethodologies to introduce asymmetry in rotor slots are proposed and the key performance characteristics like torque ripple, radial air gap forces are computed both numerically and analytically. Radial forces obtained from the finite element method are coupled to the analytical tool forcalculating the magnetic noise. A spectral method to calculate and separate the radial forces into vibration modes and their respective frequencies is proposed and validated for a standard 4-pole induction motor. The influence of rotor slot number, eccentricity and skew on radial forces and magnetic noise are studied using finite element method in order to understand the vibrational and acoustic behavior of the machine, especially for identifying their sources. The validated methods on standard motors are applied for investigating the asymmetrical rotor slot machines.</p><p>Radial air gap forces and magnetic noise spectra are computed for the novel dual and sinusoidal symmetrical rotors and compared with the standard symmetrical rotor. The results obtained showed reduced radial forces and magnetic noise in asymmetrical rotors, both for the eccentric and noneccentric cases. Based on the results obtained some guide lines for designing  asymmetrical rotor slots are established. Magnitudes of the harmful modes of vibration observed in the eccentric rotors, which usually occur in reality, are considerably reduced in asymmetrical rotors showing lower sound intensity levels produced by asymmetrical rotors. The noise level from mode-2 vibration in a 4-pole standard 15 kW motor running with 25% static eccentricity is decreased by about 6 dB, compared to the standard rotors. Hence improved performance can be achieved by removing skew which reduces cross current losses and by employing asymmetrical rotor slots same noise level can be maintained or can be even lowered.</p><p> </p><p> </p>
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6

Позовний, Олександр Олександрович, Александр Александрович Позовный та Oleksandr Oleksandrovych Pozovnyi. "Вплив багатошпаринних ущільнень на герметичність та вібронадійність відцентрових насосів". Thesis, Сумський державний університет, 2021. https://essuir.sumdu.edu.ua/handle/123456789/86323.

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Дисертаційна робота присвячена розробленню методики розрахунку та вдосконаленню геометрії багатошпаринних ущільнень відцентрових насосів. Наукове обґрунтування та опрацювання методики визначення статичних і динамічних силових характеристик та уточнений розрахунок величини витоків в багатошпаринних ущільненнях дають змогу покращити вже існуючі конструкції та підвищити енергоефективність при забезпеченні допустимо низького рівню вібрацій роторів відцентрових насосів. На основі аналізу літературних джерел встановлено можливість підвищення загального коефіцієнту корисної дії (К.К.Д.) відцентрових насосів за рахунок зменшення об’ємних втрат на передніх та міжступеневих шпаринних ущільненнях при великих значеннях перепадів тиску та швидкостях обертання роторів. Це можливо за рахунок використання багатошпаринних ущільнень. Конструкції таких ущільнень створюється послідовно розміщеними дроселями, з’єднаними між собою камерами, коефіцієнт гідравлічних втрат яких приблизно дорівнює сумі коефіцієнтів втрат всіх дроселів. Відповідно зменшується витоки через ущільнення. З літератури стає зрозумілим, що в таких ущільненнях, як і у звичайних одношпаринних, не тільки обмежуються втрати, а й внаслідок високих значень перепадів тиску виникають радіальні сили, які впливають на динамічні характеристики роторів відцентрових насосів, тобто вони виконують функції гідродинамічних опор і можуть, як стабілізувати ротор, так і викликати втрату його динамічної стійкості. Для визначення розподілу тиску в короткому кільцевому каналі з відповідними граничними умовами прийнято рівняння течії в’язкої нестисливої рідини (рівняння Рейнольдса). Отримані аналітичні залежності для розрахунку радіальних сил, що виникають в кільцевих дроселях двохшпаринних і трьохшпаринних ущільнень, зумовлені радіальним зміщення вала та перекосом осей ротора та статора. Проведена оцінка впливу конусності щілин на силові коефіцієнти багатошпаринного ущільнення. Розглядаються сили, зумовлені осьовим перепадом тиску p F і потоком витіснення: дисипативна сила d F і циркуляційна сила сF , які можуть привести до втрати стійкості, яка супроводжується автоколиваннями ротора з великою амплітудою. Інерційні сили (гіроскопічна і сила інерції), зважаючи на їх відносно малі значення, не враховуються. Отримані аналітичні залежності для визначення амплітуди та фази вимушених радіальних коливань вала, а також визначення умови його стійкості. Також розглянуті вільні коливання ротора в багатошпаринному ущільненні та отримані частоти власних коливань системи ротор-ущільнення з врахуванням демпфірування в залежності від частоти обертання при різних значеннях ущільнювального тиску. Виконано порівняння величин динамічних коефіцієнтів та витоків двох- та трьохшпаринних ущільнень з одношпаринним ущільненням при умові використання достатньо великих камер, яке демонструє суттєві переваги багатошпаринних ущільнень. Так, наприклад, трьохшпаринне ущільнення з однаковим радіальним зазором всіх шпарин ущільнення має у середньому на 48,5 % більші динамічні коефіцієнти, та на 41,2 % менші витоки, а подібне двохшпаринне ущільнення має на 15 % більшу пряму жорсткість та на 9,1 % більше пряме демпфірування та на 20,6 % менші витоки. Для проведення експериментальних досліджень на базі проблемної лабораторії гермомеханіки та вібродіагностики кафедри комп’ютерної механіки імені Володимира Марцинковського виконана модернізація існуючої експериментальної установки для досліджень одношпаринних ущільнень. Установка забезпечує подачу ущільнювального тиску від 0 до 1 МПа, при умові достатнього гасіння його пульсацій, при величині витоків до 1,2 л/с та частоті обертання вала - 8000 об/хв. Виконувались експериментальні дослідження трьохшпариного ущільнення двох варіантів конструкцій: з однаковими радіальними зазорами на кожній шпарині і з вдвічі збільшеним радіальним зазором на другій шпарині при двох осьових розмірах з’єднувальних камер – 1 та 3 мм. Для визначення впливу радіальної та тангенціальної сил, окремо проведені дослідження як з не обертовим, так і з обертовим валом. В експериментальних дослідженнях з не обертовим валом проведено вимірювання розподілу тиску по довжині першої шпарини та в з’єднувальній камері на виході з неї у двох протилежних радіальних положеннях вала – у місці з мінімальним та максимальним радіальним зазором; та сумарних витоків з ущільнення в залежності від радіального зміщення вала (ексцентриситету) в діапазоні 0,04-0,16 мм при різній величині ущільнювального тиску 1,25; 2,5; 5; 7,5, 10 атм. Отримані результати по розподілу гідростатичного тиску по довжині першої шпарини показали, що перший варіант конструкції трьохшпаринного ущільнення має децентруючу радіальну гідростатичну силу, яка підвищується зі збільшенням радіального зміщення валу та зменшується при збільшені осьового розміру з’єднувальних камер. У другому варіанті конструкції радіальна гідростатична сила на першій шпарині у більшості випадків має центруючу дію, та сумарна гідростатична радіальна сила збільшується зі збільшенням радіального зміщення вала і осьового розміру з’єднувальних камер. Величина витоків дещо зменшується з радіальним зміщенням валу для першого варіанту конструкції, але має суттєво більшу величину і майже не змінюється як від радіального зміщення, так від збільшення осьового розміру камер. Порівняння величини витоків отриманих за допомогою аналітичних залежностей з експериментальними даними для конструкцій трьохшпаринних ущільнень дало максимальну похибку 3,3 %, що підтверджує достатню адекватність обраної теоретичної моделі. Помічено, що під час експериментальних досліджень в першому варіанті конструкції при осьовому розмірі з’єднувальних камер 3 мм при відсутності власного обертання спостерігався прецесійний рух вала, траєкторія якого відстежувалась на екрані осцилографа. В експериментальних дослідженнях з обертальним валом отримані амплітудно-частотні характеристики (АЧХ), траєкторії руху та значення витоків в залежності від частоти обертання вала при різних значеннях ущільнювального тиску. Визначено, що у більшій частині досліджуваного діапазону параметрів, загальне число Рейнольдса у трьохшпаринному ущільненні відповідає турбулентному режиму течії. Аналіз АЧХ показав, що у другому варіанті конструкції ущільнення з удвоєним радіальним зазором другої шпарини та збільшеним осьовим розміром з’єднувальних камер при збільшенні ущільнювального тиску суттєво збільшуються значення критичних швидкостей. В першому варіанті конструкції зі зменшеним осьовим розміром з’єднувальної камери тенденція є зворотною. Для обох варіантів конструкцій зі збільшенням ущільнювального тиску дещо збільшуються критичні амплітуди коливань. При чому, у другому варіанті конструкції трьохшпаринного ущільнення максимальна критична амплітуда коливань на 36 % менша. Аналіз траєкторій руху стінки вала підтверджує той факт, що найменшу величину амплітуди коливань має другий варіант конструкції ущільнення зі збільшеним осьовим розміром з’єднувальних камер. Також підтверджено, що як і у традиційних шпаринних ущільненнях, витоки зменшуються зі збільшенням частоти обертання вала. Порівняння експериментально отриманих амплітудно-частотних характеристик(АЧХ) з АЧХ отриманими за аналітичними залежностями, показало краще їх співпадіння для другого варіанту конструкції зі збільшеними з’єднувальними камерами. Так максимальна відносна похибка дорівнювала 15 %. Це пояснюється тим, що в аналітичних розрахунках не враховується рух рідини в циліндричних каналах з’єднувальних камер. Для дослідження гідродинаміки течії рідини у циліндричних каналах багатошпаринного ущільнення використовувався програмний комплекс ANSYS CFX, в якому за допомогою метода скінченних об’ємів елементів розв’язувалися рівняння Нав'є-Стокса осереднені за Рейнольдсом, які замикались k-ɛ моделлю турбулентності. Розглядалась ізотермічна течія рідини (води). Точність використання вищенаведеної моделі турбулентності підтверджується наявними в літературі результатами розрахунків шпаринних ущільнень. Проведені розрахункові дослідження трьохшпаринних та двохшпаринних ущільнень в стаціонарній та нестаціонарній постановках. Отримані поля швидкостей, розподіли тиску та значення витоків. В стаціонарній постановці розглядалось радіальне зміщення валу без урахування його власного обертання. Порівняння отриманих розподілів гідростатичного тиску з результатами експериментальних досліджень показало, що максимальна похибка між результатами розрахунків та експериментів для конструкцій трьохшпаринного ущільнення склала 12,4 %, а максимальна відносна різниця за величиною витоків склала 15% при максимальному значенні величини радіального зміщення вала. Виникнення в експериментальних дослідженнях прецесії вала без його власного обертання в першому варіанті конструкції пояснюється результатами розрахункових досліджень. Так, радіальні коливання вала вздовж вертикальної осі, які викликані децентруючою силою в цьому напрямку, при мінімальному випадковому стаціонарному зміщенні валу в горизонтальному напрямку, можуть викликати додаткові радіальні коливання в цьому напрямку. Це пов’язано з виникненням негативного демпфірування в першому варіанті конструкції трьохшпаринного ущільнення. В нестаціонарній постановці розглядався рух вала за циліндричною траєкторію при прямій синхронній прицесії. Величина ексцентриситету дорівнювала 10 % від величини зазора. За відомими аналітичним залежностями, за величинами радіальних та тангенціальних сил, отриманими в розрахункових дослідженнях, оцінювались динамічні коефіцієнти жорсткості та демпфірування багатошпаринних ущільнень. Нестаціонарний аналіз динаміки валу в трьохшпаринному ущільненні показав, що максимальні сумарні значення динамічних коефіцієнтів має другий варіант конструкції зі збільшеною камерою. Основні динамічні коефіцієнти – прямі жорсткості і демпфірування та перехресне демпфірування мають позитивне значення, негативне значення перехресної жорсткості лише збільшує стабілізуючу дію сил на вал в цьому варіанті конструкції ущільнення. Що також підтверджується результатами експериментальних досліджень. Подальше намагання покращити динамічні характеристики вала в трьохшпаринних ущільненнях за рахунок використання нових конструкцій з гальмами та обертовими лопатками, які встановлюються на стаціонарних та роторних елементах з’єднувальних камер, не дало очікуваного результату. Так, пряма жорсткість має негативну величину для цих конструкцій ущільнень. Присутність гальм та лопаток не зменшує, а навпаки збільшує перехресну жорсткість в конструкції трьохшпаринного ущільнення. Виконані розрахункові дослідження турбулентної течії нестисливої рідини для трьох варіантів конструкцій двохшпаринного ущільнення: базової конструкції (змінювався лише осьовий розмір з’єднувальної камери), конструкції з радіальною проточкою на зовнішньому радіусі та конструкції з радіальною проточкою на внутрішньому радіусі з’єднувальної камери. Розрахункові дослідження в стаціонарній і нестаціонарній постановках показали більшу ефективність другого варіанту конструкції, який має найбільшу величину радіальної гідростатичної центруючої сили і змінення направлення сили відбувається при менших осьових розмірах з’єднувальної камери, та відповідно має найбільші значення прямої жорсткості та демпфірування. В результаті проведених розрахункових досліджень видані практичні рекомендації по величині осьового розміру і конструкції з’єднувальної камери та проаналізовано вплив з’єднувальної камери на гідродинамічні сили, які виникають в циліндричних зазорах двохшпаринних ущільнень. Достовірність отриманих наукових положень і результатів забезпечується: достатнім узгодженням розрахункових та експериментальних даних; використанням методів і засобів вимірювання, що забезпечують допустиму похибку експериментального визначення основних величин.<br>The thesis is devoted to the development of calculation methods and improvement of the geometry of multi-annular seals of centrifugal pumps. Scientific substantiation and elaboration of the method of determining static and dynamic forces characteristics and refined calculation of leakage in multi-clearance seals allow to improve existing structures and increase energy efficiency while ensuring a low level of vibration of centrifugal pump rotors. Based on the analysis of literature sources, the possibility of increasing the total efficiency of centrifugal pumps by reducing the volume losses on the front and interstage annular seals, with large values of pressure drops and rotational speeds. This is possible through the use of multi-clearance seals. Sequentially placed throttles connected by chambers creates the design of such seals, the coefficient of hydraulic losses is approximately equal to the sum of the coefficients of loss of all throttle. Accordingly, leakage through seals is reduced. From the literature, it is clear that in such seals, as in conventional single-clearance, not only limited losses but also due to high values of pressure drops radial forces that affect the dynamic characteristics of the rotors of centrifugal pumps, i.e. they perform hydrodynamic support and can both to stabilize the rotor and to cause the loss of its dynamic stability. The flow equation of a viscous incompressible fluid (Reynolds equation) determines the pressure distribution in a short annular channel with corresponding boundary conditions. Analytical dependences for calculating radial forces arising in the ring chokes of two-annular and three-annular seals due to the radial displacement of the shaft and the skew of the axes of the rotor and stator are obtained. The influence of the conicity of the slits on the force coefficients of the multi-annular seals is estimated. The forces due to the axial pressure drop p F and the displacement flow are considered: dissipative force dF and circulating force сF , which can lead to loss of stability, accompanied by self-oscillations of the rotor with a large amplitude. Inertial forces (gyroscopic and inertial forces), due to their relatively small values, are not taken into account. Analytical dependences for the determination of amplitude and phase of forced radial oscillations of a shaft and the definition of its stability condition are received. The free oscillations of the rotor in the multi-annular seal are also considered, and the natural frequencies of the rotor-seal system are obtained, taking into account damping depending on the rotational frequency at different values of the sealing pressure. Comparing the values of dynamic coefficients and leakage of two- and threeannular seals with a one-clearance seal under the condition of using sufficiently large chambers demonstrates the significant advantages of multi-annular seals. For example, a three-clearance seal with the same radial clearance has an average of 48.5% higher dynamic coefficients and 41.2% fewer leakages. A similar twoclearance seal has 15% greater direct stiffness and 9.1 % more direct damping, and 20.6% fewer leaks. To conduct experimental research on the basis of the problem laboratory of hermomechanics and vibrodiagnostics of the Department of Computer Mechanics named after Volodymyr Martsynkovskyy, the modernization of the existing experimental installation for the study of single-well seals was performed. The unit provides the supply of sealing pressure from 0 to 1 MPa, provided sufficient suppression of its pulsations, with the value of leaks up to 1.2 l/s and shaft speed - 8000 rpm. Experimental studies of three-annular seals of two design variants were performed: with the same radial clearance on each hole and twice the radial clearance on the second hole with two axial sizes of connecting chambers - 1 and 3 mm. To determine the influence of radial and tangential forces, separate studies with both non-rotating and rotating shafts were conducted. In experimental studies with a non-rotating shaft, the pressure distribution was measured along the length of the first clearance and in the connecting chamber at its outlet in two opposite radial positions of the shaft - in the place with the minimum and maximum radial clearance; and total leaks from the seal depending on the radial displacement of the shaft in the range of 0.04-0.16 mm (eccentricity) at different values of the sealing pressure of 1.25; 2.5; 5; 7.5, 10 atm. The obtained results on the distribution of hydrostatic pressure along the length of the first clearance showed that the first design of the three-clearance seal has a decentralized radial hydrostatic force, which increases with increasing radial displacement of the shaft and decreases with increasing axial size of connecting chambers. In the second variant, the radial hydrostatic force on the first clearance has a centering effect in most cases. The total hydrostatic radial force increases with increasing radial displacement of the shaft and the axial size of the connecting chambers. The magnitude of the leaks decreases slightly with the radial displacement of the shaft for the first design variant but has a significantly larger value and does not change almost from the radial displacement and increase in the axial size of the chambers. Comparison of the magnitude of leaks obtained with the help of analytical dependences with experimental data for the construction of three-annular seals gave a maximum error of 3.3%, which confirms the sufficient adequacy of the chosen theoretical model. It was noticed that during experimental studies in the first version of the design, with an axial size of the connecting chambers of 3 mm in the absence of its own rotation, precession movement of the shaft was observed on the oscilloscope screen. In experimental studies with a rotating shaft, amplitude-frequency characteristics (frequency response), trajectories and values of leaks depending on the frequency of rotation of the shaft at different values of sealing pressure were obtained. It is determined that in most of the studied range of parameters, the total Reynolds number in the three-annular seal corresponds to the turbulent flow regime. The frequency response analysis showed that in the second variant of the seal design with a double radial clearance of the second annular and an increased axial size of the connecting chambers, the values of critical velocities increase significantly with increasing sealing pressure. The trend is reversed in the first version of the design with the reduced axial size of the connecting chamber. The critical oscillation amplitudes increase slightly as the sealing pressure increases for both designs. Moreover, in the second variant of the three-annular seal design, the maximum critical amplitude of oscillations is 36% smaller. The analysis of the shaft wall trajectories confirms that the second value of the seal design with the increased axial size of the connecting chambers has the smallest value of the oscillation amplitude. It is also confirmed that leaks decrease with increasing shaft speed, as in traditional annular seals. Comparison of the experimentally obtained frequency response with the frequency response obtained by analytical dependences showed a better match for the second design option with enlarged connecting chambers. Thus, the maximum relative error was 15%. This is because the analytical calculations do not consider fluid movement in the cylindrical channels of the connecting chambers. The ANSYS CFX software package was used to study fluid flow in cylindrical multi-annular sealing channels. The Reynolds-averaged Navier-Stokes equations were solved using the finite-volume element method, which closed the k-ɛ turbulence model. The isothermal flow of liquid (water) was considered. The accuracy of using the above model of turbulence is confirmed by the results of calculations of annular seals available in the literature. Calculated research of three-annular and two-annular seals in stationary and non-stationary installations is carried out. Velocity fields, pressure distributions and leak values are obtained. The radial displacement of the shaft without taking into account its own rotation was considered in the stationary setting. Comparison of the obtained distributions of hydrostatic pressure with the results of experimental studies showed that the maximum error between the results of calculations and experiments for the structures of the three-annular seal was 12.4%, and the maximum relative difference in the magnitude of the leaks was 15% with the maximum value of the radial displacement of the shaft. Numerical calculations explain the occurrence in experimental research of the precession of a shaft without its own rotation in the first variant of a design. Thus, the radial oscillations of the shaft along the vertical axis, which are caused by the decentralizing force in this direction, with the minimal accidental stationary displacement of the shaft in the horizontal direction, can cause additional radial oscillations in this direction. This is due to the negative damping in this version of the three-annular seal design. In a non-stationary setting, the precession movement of the shaft along a cylindrical trajectory was considered. The magnitude of the eccentricity was equal to 10% of the magnitude of the gap. According to the known analytical dependences, the values of radial and tangential forces obtained in the calculation studies, the dynamic stiffness and damping coefficients of multi-annular seals were estimated. Non-stationary analysis of the shaft dynamics in a three-annular seal showed that the maximum total values of the dynamic coefficients have the second design option with an enlarged chamber. The main dynamic coefficients - direct stiffness, damping, and cross-damping have a positive value. The negative value of cross-stiffness only increases the stabilizing effect of forces on the shaft in this version of the seal design. The results of experimental studies also confirm this. However, attempts to improve the dynamic characteristics of the shaft in three-annular seals by using new designs with brakes and rotating vanes, which are installed on stationary and rotary elements of the connecting chambers, did not give the expected result. So, the direct stiffness has a negative value for these seal designs. The presence of brakes and blades does not reduce but rather increases the cross-stiffness in the design of the three-annular seal. Numerical calculations of the turbulent flow of incompressible fluid were performed for three variants of two-annular seal designs: basic design (only the axial size of the connecting chamber changed), design with a radial groove on the outer radius and design with the radial groove on the inner radius of the connecting chamber. Computational studies in stationary and non-stationary settings have shown greater efficiency of the second design variant, which has the largest value of radial hydrostatic centering force and changes in the direction of force occurs at smaller axial dimensions of the connecting chamber and therefore has the highest values of direct stiffness and damping. As a result, practical recommendations on the axial size and design of the connecting chamber are issued, and the influence of the connecting chamber on the hydrodynamic forces that occur in the cylindrical gaps of two-annular seals is analyzed. The reliability of the obtained scientific statements and results is ensured by: sufficient coordination of calculated and experimental data, using methods and means of measurement that allow the permissible error of experimental determination of basic values.
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7

Rosentino, Junior Arnaldo José Pereira. "Estimativa dos esforços eletromecânicos em transformadores submetidos a um curto-circuito trifásico." Universidade Federal de Uberlândia, 2010. https://repositorio.ufu.br/handle/123456789/14437.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Power transformers are essential and a large part of the asset cost structure of the electrical power system. When they present any defect or failure, it will be required high costs to repair or replace them, due their commercial costs and by the capability loss to transmit power during a period of time. Generally, transformer failure can occur as a result of the weakness insulation caused by the electrochemical processes involving the cooling liquid (oil), by vibrations due the electromagnetic forces in normal operation, i.e., steady state, and also by winding deformation as the result of short-circuits. It is expected that a transformer will experience and survive a number of short circuits during its service life. But one such event will cause some slight winding movement, which can gradually increasing and the ability of the transformer to withstand further electromechanical forces will be then reduced. It is therefore very important to check the mechanical condition of transformers periodically, particularly for older units, to provide an early warning of an impending catastrophic failure. Thus a specialist technique is required for the monitoring and assessment of mechanical condition of winding transformer. Despite designers and manufacturers, as well as the operation and maintenance technicians of power supply companies worry about this subject, new methodologies and tools to assess the strength effects as the result of short circuits in transformers are still necessaries. So, this work proposes to know the strength characteristics caused by the radial and axial forces in winding transformers. In this context, it will be presented different strengths that can occur in winding transformer, identifying the principal failures as the result of these stresses. Besides, it will be developed an analytical method to evaluate the forces and stresses in winding three phase transformer under a three phase short circuit. Finally, the analytical method results will be compared with a computer simulation based in time domain using the software FEMM, which applies the finite element method.<br>Transformadores de potência são equipamentos essenciais aos sistemas elétricos e também um de seus componentes de maior preço. Quando estes equipamentos se danificam ou apresentam algum tipo de falha, o seu reparo ou até mesmo sua substituição demanda altíssimos custos financeiros, tanto pelo alto valor comercial destes equipamentos como pela perda temporária da capacidade de transmissão de energia elétrica. Muitas falhas destes equipamentos devem-se à redução da suportabilidade da isolação dos seus condutores/enrolamentos causado pelos fenômenos eletroquímicos do líquido de resfriamento (óleo), pelas vibrações produzidas pelas forças eletromecânicas durante a sua operação normal, ou seja, em regime permanente, e também pelas deformações dos enrolamentos causadas pelas altas correntes de curto-circuito. Espera-se, no entanto, que um transformador suporte um determinado número de curtos-circuitos durante seu tempo de operação. No entanto, verifica-se que cada evento poderá provocar pequenos deslocamentos relativos nos enrolamentos, os quais podem aumentar cumulativamente, reduzindo desta forma a capacidade do transformador de suportar novos esforços eletromecânicos. Neste contexto, torna-se importante a verificação periódica das suas condições mecânicas, principalmente nas unidades com muito tempo de operação, de forma a se obter subsídios para impedir falhas catastróficas. O emprego de técnicas especiais é requerido para o monitoramento e avaliação das condições mecânicas do enrolamento de um transformador. Apesar de este assunto ser uma preocupação constante dos projetistas e fabricantes de transformadores, bem como dos profissionais de manutenção e operação das empresas de energia elétrica, há certa carência de metodologias e ferramentas consistentes para se avaliar os efeitos dos esforços mecânicos decorrentes das elevadas correntes transitórias sobre estes equipamentos. Nessa perspectiva, este trabalho tem por meta o entendimento das características dos esforços mecânicos causados pelas forças radiais e axiais nos enrolamentos dos transformadores. Para tanto, esta dissertação mostrará os diferentes tipos de esforços eletromecânicos passíveis de ocorrer nos enrolamentos de um transformador, identificando os principais tipos de falhas provocadas por essas solicitações. Em seguida, será desenvolvida uma metodologia analítica para estimar as forças e estresses nos enrolamentos de um transformador trifásico submetidos a um curto-circuito trifásico. Assim, os valores obtidos pela metodologia analítica serão confrontados com resultados de uma simulação computacional no domínio do tempo utilizando-se o programa FEMM baseado na técnica de elementos finitos.<br>Mestre em Ciências
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8

Sayer, Min-hee Shin. "Evolution of radial force balance and radial transport over L-H transition." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45911.

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Understanding of plasma confinement modes is an essential component in development of a fusion reactor. Plasma confinement directly relates to performance of a fusion reactor in terms of energy replacement time requirements on other design parameters. Although a variety of levels of confinement have been achieved under different operating conditions in tokamaks, tokamak confinement is generally identified as being either Low (L-mode--poor confinement) or High (H-mode--good confinement) In operation of a tokamak experiment, the plasma confinement condition generally changes from L-mode to H-mode over a few hundred milliseconds, sometimes quite sharply. Such a difference in transition period seems to be largely due to operating conditions of the plasma. Comparison of experimental data exhibits various distinctions between confinement modes. One noteworthy distinction between confinement modes is development of steep density and temperature gradients of electrons and ions in the plasma edge region of High confinement, H-modes, relative to Low-confinement, L-modes. The fundamental reason for the change for L-mode to H-mode is not understood. Previous studies have suggested i) the development of reduced diffusive transport coefficients that require a steepening of the gradients in a localized region in the edge plasma, the "transport barrier" in H-mode confinement ii) the radial force balance between pressure gradient forces and electromagnetic (radial electric field and VxB) forces require radial particle fluxes to satisfy a pinch-diffusion relation. A recent study suggests that the major difference between L-mode and H-mode are associated with the electromagnetic forces in the "pinch velocity" and the pressure gradient, not in the diffusion coefficients that multiplies the pressure gradient. The research will examine in detail the time evolution of the radial force balance and the particle and energy transport during the L-H transition. For the analysis, DIII-D shot #118897 is selected for transition between L- and H-mode confinements. Plasma conditions in L-mode, near the L-H transition and following the transition are selected for analysis of various parameter profiles. The initial analysis will be based on the four principal equations for plasma: particle balance, momentum balance, force balance and heat conduction. Based on these equations, specific equations have been derived: toroidal and radial momentum balances, diffusion coefficient, pinch velocity and heat conduction relation for calculation of parameters. The analysis of these equations, using the measured data, will establish how various terms in the radial force balance (radial electric field, VXB (electromagnetic) force, and pressure gradient) and the diffusive transport coefficients evolve over the confinement mode transition.
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9

Viitala, R. (Risto). "Dynamic radial bearing force measurement of flexible rotor." Master's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201809062733.

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Dynamic characteristics of a paper machine roll have been widely investigated for decades. Vibration of the rolls decrease the paper quality and excites the structures of the paper machine. Therefore, vibration must be avoided and kept at its minimum. Vibration of a rotor develops periodic radial bearing forces, which are connected to the amplitude and the frequency of the vibration. Vibration based forces are unnecessary dynamic forces, which increase the bearing load in addition to unavoidable rotor mass and the external loads of the process. This experimental study presents the amplitudes of the dynamic bearing force caused by a vibrating rotor and enables further measurements and research about the correlation between the radial bearing force and e.g. acceleration data. During the research knowledge about the dynamic behavior of the rotor and developed forces can be increased. The improved knowledge leads to a lower bearing force level, which decreases the oversizing of the structures, enables the design of lighter and more cost-effective structures, extends the lifespan of the machine and improves the quality of the end product. The dynamic radial bearing force amplitudes of a paper machine roll are merely available through simulation models, since physical force sensors are not mounted on the paper machines. Typically, the monitoring of a paper machine is focused on the vibrations of the paper machine rolls, since it is more relevant for to the quality of the paper than the amplitudes of force. Vibration troubleshooting and monitoring tasks have typically been realized through the easy-installed accelerometer measurements. The force measurement of the paper machine roll can produce similar information about the behavior of the rotor and its vibrations as acceleration measurement in addition to the radial force amplitudes. However, utilization of force measurements in vibration monitoring was not found based on a literature survey. The radial bearing force measurement was accomplished by building a test rig and a measurement device for an industrial-size paper machine roll. The radial bearing forces were measured as close as possible to the action point of the load to produce reliable results. The results present the force measurement data, which were acquired with the calibrated and verified measurement device implemented during this study. The measured results revealed the forces affecting on both ends of the test roll. The data was analyzed with Fast Fourier Transform (FFT) to present the forces in the frequency domain and to investigate their harmonic components. The measured forces, which were divided into harmonic components, could be discovered and destabilizing excitations could be defined more efficiently. Based on the present study high harmonic components could be distinguished with the force measurement. The results were compared with two reference measurements, which utilize acceleration and position sensors. The results cannot be generalized, since the measuring results consider only the roll of this research. The roll, the bearings, the bearing support and the foundation form the rotating system, which is always individual. Parameters and excitations affecting to the behavior of the roll are different in every roll. However, the similar behavior can be assumed to be on other flexible rotors as well and those can be measured with similar methods as the present study. In further research additional knowledge about the behavior of the roll and correlations between force, position and acceleration can be achieved for both the scientific and practical engineering purposes with the dynamic bearing force measurement and a simultaneous acceleration or position measurement<br>Paperikoneen telan värähtelyominaisuuksia on tutkittu laajasti jo vuosikymmeniä. Värähtely heikentää paperin laatua ja aiheuttaa herätettä paperikoneen rakenteisiin. Tästä johtuen värähtely yritetään pitää minimaalisena. Roottorin värähtely aiheuttaa jaksollisia laakerivoimia, jotka ovat yhteydessä värähtelyyn. Värähtelyn aiheuttamat voimat ovat ei-toivottuja dynaamisia voimia, jotka lisäävät laakerivoimia välttämättömän roottorimassan ja muiden prosessista aiheutuvien rasitusten lisäksi. Tämä kokeellinen tutkimus keskittyy värähtelevän roottorin aiheuttamiin dynaamisiin voimiin ja mahdollistaa myöhemmän mittaamisen ja korrelaatioiden tutkimisen laakerivoimien ja esimerkiksi kiihtyvyysmittauksen välillä. Tietoa roottorin dynaamisesta käyttäytymisestä ja syntyvistä voimista voidaan parantaa tällä tutkimuksella. Paperikoneen telan dynaamisten ominaisuuksien parempi tunteminen vähentää rakenteiden ylimitoitusta, mikä mahdollistaa rakenteiden suunnittelun kevyemmäksi ja halvemmaksi, lisää koneen käyttöikää ja parantaa lopputuotteen laatua. Telan värähtelyn aiheuttamia dynaamisia laakerinvoimia on saatavilla vain simuloimalla, mikä tarkoittaa, että fyysisiä voima-antureita ei ole asennettuina paperikoneissa. Yleensä paperikoneen anturointi keskittyy paperikoneen telojen värähtelyyn, sillä se on isompi tekijä paperin laaduntarkkailussa kuin voimamittaus. Värähtelymittaukseen perustuvaa vianetsintää ja prosessivalvontaa on tehty tyypillisesti helposti kiinnitettävillä kiihtyvyysantureilla. Voimamittaus pystyy tuottamaan saman informaation roottorin käyttäytymisestä ja sen värähtelystä kuin kiihtyvyysmittaus laakerivoimien lisäksi. Kuitenkaan, voimamittausta ei käytetä värähtelymittauksiin kirjallisuusselvityksen mukaan. Laakerivoimamittaus suoritetaan rakentamalla koepenkki sekä mittalaite teollisuudessa käytettävälle paperikoneen telalle. Laakerivoimat pyritään mittaamaan mahdollisimman läheltä voimanvaikutuspistettä, että saavutettaisiin mahdollisimman luotettava tulos. Mittatulokset saatiin kalibroidulla ja verifioidulla mittalaitteella, joka oli rakennettu tämän työn aikana. Mittaustulokset paljastivat telan laakereihin syntyvät voimat kummassakin päässä telaa. Tulokset analysoitiin käyttäen nopeaa Fourierin muunnosta (FFT), jotta voimat saatiin taajuustasoon harmonisten komponenttien tutkimiseksi. Mitatut voimat ja niiden amplitudit, jotka olivat esitettyinä harmonisina komponentteina, voitiin löytää ja telan värähtelyä aiheuttavat herätteet voitiin rajata tehokkaammin. Tämän tutkimuksen perusteella voitiin huomata, että korkeat harmoniset taajuudet voitiin havaita voimamittauksella. Tuloksia verrattiin kahteen referenssimittaukseen, jotka oli toteutettu kiihtyvyys- ja paikka-antureilla. Tuloksia ei voitu yleistää, sillä mittaustulokset koskevat vain tämän tutkimuksen telaa. Tela, laakerit, laakerin tuenta ja perusta muodostivat pyörivän systeemin, mikä on aina yksilöllinen. Parametrit ja herätteet, jotka vaikuttavat telan käyttäytymiseen muuttuvat joka telassa. Kuitenkin samanlaista käyttäytymistä voidaan olettaa olevan myös toisissa joustavissa roottoreissa ja ne voidaan mitata samalla tavalla kuin tässä tutkimuksessa. Myöhemmässä tutkimuksessa voidaan saavuttaa lisäarvoa ja korrelaatioita laakerivoiman, siirtymämittauksen ja kiihtyvyysmittauksen välillä tieteellisiin ja käytännön tarkoituksiin dynaamisella laakerivoimamittauksella
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10

Valente, Giorgio. "Radial force control of bearingless multi-sector permanent magnet machines." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52086/.

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The radial force control has been widely investigated for a variety of machine topologies aiming at the reduction of the mechanical stress on bearings as well as the overall vibration. Furthermore, it can be also applied to bearingless drives where the force control can be exploited to suspend the rotor element. Traditional radial force control techniques rely on two independent sets of windings dedicated to torque and suspension force, respectively. However, different winding structures can be employed to reduce the overall system complexity. Multiphase machines, in particular, offer the possibility to embed the radial force and torque generation in a single winding set and possess an enhanced fault tolerant capability. This thesis presents an alternative radial force and torque control technique for a multiphase sectored permanent magnet synchronous machine. The mathematical model of the machine and the theoretical investigation of the force production principle are provided. A force control methodology based on the minimization of the copper losses is described and adopted to calculate the d-q axis current references. The predicted performances of the test machine are benchmarked against finite elements analysis. An experimental rig has been manufactured in order to validate the radial force and torque control. The experimental validation focuses on the suppression of selected vibration frequencies at different speeds. The radial force control has been also exploited to levitate the rotor in order to obtain a two degrees of freedom bearingless drive. The fault tolerant capabilities have been investigated and experimentally tested considering the open-circuit of one three-phase winding. The tuning of the x-y axis position controller has been investigated and a state space approach has been followed to synthesize different position controllers.
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11

Hammarstedt, Kaisa. "Tillväxtreaktioner efter gallring på försöksytor med olika täthet i Östergötland." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-72103.

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Since the 1950-ies, the dominating silvicultural system in Sweden has included establishment and management of even-aged stands, including final felling. Alternative systems such as continuous cover forestry are increasingly catching interest due the lower impact on stand structure and biodiversity advantages for shade-tolerant species. However it is unknown especially to southern Sweden how trees in a continuous cover forestry system react to common silvicultural measures such as thinning. Therefore the effect of different levels of thinning on the radial growth of larger trees was measured and compared to the ingrowth and proportion of live crown at a site in Östergötland. Unlike previous findings the radial growth was higher in the treatment that had been slightly thinned than in the one that had been heavily thinned. The ability to react with increased radial growth after thinning was not depending on the thinning regime but on the tree’s reaction to a previous thinning. Only trees that had not reacted to the previous thinning increased in radial growth. The radial growth varied more within a treatment than between treatments, which points at the difficulty to allocate growth to specific trees.
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12

Islam, Mohammed Rakibul. "Cogging Torque, Torque Ripple and Radial Force Analysis of Permanent Magnet Synchronous Machines." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1239038005.

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13

Nogueira, Ana Paula Gomes. "Desenvolvimento de método para medição da força radial em endopróteses aórticas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/76176.

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O desempenho das endopróteses vasculares está relacionado diretamente à sua força radial. Esta é uma importante propriedade mecânica destes dispositivos médicos, influenciada por características da matéria-prima, pelos parâmetros de processamento empregados e pela morfologia do produto. Em um ensaio de força radial, determina-se a força necessária para comprimir e para expandir uma endoprótese, ou seja, em função da variação do seu diâmetro é medida a força envolvida. Uma característica desejada nestes ensaios é que a endoprótese se comprima e se expanda de forma homogênea, mantendo sempre sua seção na forma circular, condição esta que a maioria dos métodos hoje utilizados não atende. O presente trabalho buscou desenvolver um método para ser utilizado na determinação da força radial de endopróteses aórticas. Para tanto, um dispositivo composto por uma cinta polimérica acoplada a uma máquina universal de ensaios foi criado. Para verificar a manutenção da forma circular da endoprótese, imagens foram obtidas no decorrer do ensaio. Os resultados mostraram que o dispositivo desenvolvido é capaz de manter a forma circular das endopróteses durante todo o ensaio. Para examinar a capacidade do dispositivo em detectar diferenças nas forças radiais apresentadas por endopróteses em diferentes condições, foram realizados dois estudos, um variando o diâmetro dos fios (0,2, 0,3 e 0,4 mm) utilizados na fabricação das endopróteses e outro variando o tempo de tratamento térmico (30, 45 e 60 min) das endopróteses. Sabendo-se também que as propriedades elásticas da matéria-prima (Nitinol) têm relação direta com a força radial que as endopróteses apresentam, os resultados dos testes de força radial das amostras foram confrontados com ensaios mecânicos de carregamento e descarregamento nos fios da matéria-prima. Os resultados indicaram que o dispositivo foi capaz de detectar diferenças entre valores de força radial com amostras em diferentes condições (tanto de diâmetro de fio como de tratamento térmico) e que os resultados obtidos foram coerentes com testes de carregamento e descarregamento realizados nas amostras de matéria-prima.<br>The performance of vascular endoprosthesis is directly related to their radial force that is an important mechanical property of these medical devices. It is influenced by characteristics of the raw materials, the processing parameters and the morphology of the final product. The load necessary to compress and expand an endoprostheses is determined by a radial force test, which the load involved is measured by variation of its diameter. A characteristic required during these tests is homogenous compression and expansion of the endoprostheses maintaining its diameter value, in which most methods do not attend it. The aim of this study was develop a method to determine the radial force of aortic endoprostheses. Thus, a device composed with polymer film-type connected a universal test machine was created. Results showed that device developed is able to maintain the circular section (diameter) of the endoprostheses after test. Two studies were performed in order to check the devices’s ability and detect differences in radial forces of the endoprosthesis produced by different conditions. The first condition presented the varying of the wire diameter (0.2, 0.3 and 0.4mm), that was used in the production of the endoprosthesis, and the second one showed different times of heat treatment (30, 45 and 60 min). It is also well known that the elastic properties of the raw material (Nitinol) are directly related to the radial force presented by endoprosthesis. So, samples were compared with wire loading and unloading mechanical tests. Results indicated that the device was able to detect difference among values of radial force in samples at different conditions (both wire diameter and heat treatment time) and they showed consistence of loading and unloading tests performed on samples of raw material.
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14

Liang, Wenyi. "The investigation of electromagnetic radial force and associated vibration in permanent magnet synchronous machines." Thesis, Cranfield University, 2017. http://dspace.lib.cranfield.ac.uk/handle/1826/12333.

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The rising public awareness of climate change and urban air pollution has been one of the key drivers for transport electrification. Such trend drastically accelerates the quest for high-power-and-torque-density electric drive systems. The rare-earth permanent magnet synchronous machine, with its excellent steady-state and dynamic characteristics, has been the ideal candidate for these applications. Specifically, the fractional-slot and concentrated-winding configuration is widely adopted due to its distinctive merits such as short end winding, low torque pulsation, and high efficiency. The vibration and the associated acoustic noise become one of the main parasitic issues of high-performance permanent magnet synchronous drives. These undesirable features mainly arise from mechanical connection failure, imperfect assembly, torque pulsation, and electromagnetic radial and axial force density waves. The high-power-and-torque-density requirement will only be ultimately fulfilled by the reduction of both electromagnetic active material and passive support structure. This results in inflated electromagnetic force density inside the electric machine. Besides, the sti.ness of the machine parts can be compromised and the resultant natural frequencies are significantly brought down. Therefore, the vibration and acoustic noise that are associated with the electromagnetic radial and axial force density waves become a burden for large deployment of these drives. This study is mainly dedicated to the investigation of the electromagnetic radial forced density and its associated vibration and acoustic noise in radial-flux permanent magnet synchronous machines. These machines are usually powered by voltage source inverter with pulse width modulation techniques and various control strategies. Consequently, the vibration problem not only lies on the permanent magnet synchronous machine but also highly relates to its drive and controller. Generally, the electromagnetic radial force density and its relevant vibration can be divided into low-frequency and high-frequency components based on their origins. The low-frequency electromagnetic radial force density waves stem from the magnetic field components by the permanent magnets and armature reaction of fundamental and phase-belt current harmonic components, while the high-frequency ones are introduced by the interactions between the main low-frequency and sideband highfrequency magnetic field components. Both permanent magnets and armature reaction current are the main sources of magnetic field in electric machines. Various drive-level modeling techniques are first reviewed, explored, and developed to evaluate the current harmonic components of the permanent magnet synchronous machine drive. Meanwhile, a simple yet e.ective analytical model is derived to promptly estimate the sideband current harmonic components in the drive with both sinusoidal and space-vector pulse width modulation techniques. An improved analytical method is also proposed to predict the magnetic field from permanent magnets in interior permanent magnet synchronous machines. Moreover, a universal permeance model is analytically developed to obtain the corresponding armature-reaction magnetic field components. With the permanent magnet and armature-reaction magnetic field components, the main electromagnetic radial force density components can be identified and estimated based on Maxwell stress tensor theory. The stator tooth structure has large impacts on both electromagnetic radial force density components and mechanical vibration behaviors. The stator tooth modulation e.ect has been comprehensively demonstrated and explained by both finite element analysis and experimental results. Analytical models of such e.ect are developed for prompt evaluation and insightful revelation. Based on the proposed models, multi-physics approaches are proposed to accurately predict low-frequency and high-frequency electromagnetic radial vibration. Such method is quite versatile and applicable for both integral-slot and fractional-slot concentrated-winding permanent magnet synchronous machines. Comprehensive experimental results are provided to underpin the validity of the proposed models and methods. This study commences on the derivations of the drive parameters such as torque angle, modulation index, and current harmonic components from circuit perspective and further progresses to evaluate and decouple the air-gap magnetic field components from field perspective. It carries on to dwell on the analytical estimations of the main critical electromagnetic radial force density components and stator tooth modulation e.ect. Based on the stator mechanical structure, the corresponding electromagnetic radial vibration and acoustic noise can be accurately predicted. Various analytical models have been developed throughout this study to provide a systematic tool for quick and e.ective investigation of electromagnetic radial force density, the associated vibration and acoustic noise in permanent magnet synchronous machine drive. They have all been rigorously validated by finite element analysis and experimental results. Besides, this study reveals not only a universal approach for electromagnetic radial vibration analysis but also insightful correlations from both machine and drive perspectives.
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15

Becher, Karim Johannès. "Invariants de corps en théorie des formes quadratiques et radical de Kaplansky." Besançon, 2001. http://www.theses.fr/2001BESA2038.

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Ce travail s'inscrit dans le cadre de la théorie des formes quadratiques et des algèbres simples centrales à involution sur un corps de caractéristique différente de 2, noté F dans la suite. Dans le premier chapitre, on exhibe un critère simple pour qu'un anti-automorphisme d'une F-algèbre simple centrale soit une involution. Ce critère permet de retrouver à la fois le critère d'existence d'Albert et le théorème de prolongement de Kneser pour les involutions de première espèce. On présente également des preuves nouvelles et élémentaires de deux résultats connus concernant les algèbres simples centrales de degré 2 et d'exposant 4. D'après la définition donnée par I. Kaplansky, le radical de F noté R(F) est le groupe des éléments de F qui sont représentés par toute 1-forme de Pfister. Le chapitre II vise à approfondir l'étude de cette notion. On s'intéresse en particulier au rôle que joue le radical de F vis-à-vis des formes quadratiques et des algèbres simples centrales sur F ainsi qu'à la position de R(F) par rapport aux inclusions naturelles F× [. . . ]. Afin d'obtenir des corps de niveau donné avec des propriétés supplémentaires, on introduit au chapitre V la notion de forme suprême. Une forme quadratique sur F est dite suprême si elle est anisotrope et si elle contient toute autre forme quadratique anisotrope sur F comme sous-forme. Il s'avère qu'une forme suprême est nécessairement une forme de Pfister. D'un autre côté, toute forme de Pfister anisotrope sur le corps F devient une forme supême après extensions des scalaires à un sur-corps convenable de F.
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16

VIGOUROUX, CECILE. "Microdynamique des solutions : influence des espèces paramagnétiques sur la relaxation en RMN." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10068.

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Ce travail concerne l'etude de differents systemes modeles en solution, representant les interactions inter- ou intramoleculaires. L'agent de perturbation est une espece paramagnetique. Nous utilisons le tempol (radical nitroxyde neutre), l'anion nitrosodisulfonate (radical nitroxyde charge) ou des cations lanthanide trivalents. La methode consiste a mesurer des taux de relaxation spin-reseau et des coefficients de diffusion translationnelle par resonance magnetique nucleaire, puis a elaborer un modele theorique ou les valeurs calculees sont les plus proches possibles des valeurs experimentales. Les resultats obtenus montrent la particularite du chloroforme (formation d'agregats entre molecules de chloroforme et de solute). Nous montrons egalement que le fluor est difficilement utilisable comme sonde de distance intramoleculaire pour nos systemes (sucre doublement marque par un radical tempol et un noyau #1#9f). Nous avons pu mettre en evidence par la mesure experimentale la formation d'associations entre un ion cs#+ et une molecule de tempol par un modele simultane de dynamique translationnelle et rotationnelle. Les resultats sur les cations lanthanides trivalents en presence de cations tetramethylammonium montrent que les modeles de mouvements relatifs d'ions spheriques sont parfaitement adaptes a ces systemes. Nous obtenons une adequation moins bonne en remplacant un radical neutre (tempol) par un radical charge (anion nitrosodisulfonate) en presence d'un autre anion (methanesulfonate). Nous pouvons alors etudier les proprietes electroniques des cations lanthanides. Nous montrons experimentalement la substitution des molecules d'eau par l'anion nitrate complexant dans le cas du gd#3#+. Nous estimons les parametres de champ cristallin des cations lanthanides hydrates par des mesures de deplacements paramagnetiques.
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17

Cahill, Damien Connolly. "The radical neo-liberal movement as a hegemonic force in Australia 1976-1996 /." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20041217.152455/index.html.

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18

Schofield, Darci A. "Vegetation Dynamics and Tree Radial Growth Response in Harvest Gaps, Natural Gaps, and Closed Canopy Conditions in Maine's Acadian Forest." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/SchofieldDA2003.pdf.

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19

Arfaoui, Yousef K. "Evaluation of a new instrument for measuring segmented radial force of SE-stents implemented in the LGF." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223932.

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Endovascular surgery is a relatively new, rapidly growing, clinical technique and research area. A new endovascular tool has been developed by Endovascular Development AB, the Liungman Guidewire Fixator (LGF) that secures the distal position of a guidewire. The design of the LGF resembles a nitinol (Nickel-Titanium) stent and exerts a radial force against the blood vessel wall. It is desirable to have a well-founded understanding of all the mechanical characteristics of the product from a medical technology safety perspective.   There are different methods for uniformly measure the radial force of an object, i.e. where one single total radial force represents the entire object. This report investigates the possibility for segmented radial force measurement by the development of a new measuring instrument. A prototype of the measuring instrument has been produced to test if the proposed method can be implemented or not.   The prototype has been designed, developed and constructed to measure the radial force of individual segments of the stent. The stent segments were created using iris diaphragms and their resistance to radial change were measured using strain gauges. The concept was to measure the radial force differences between each segment with respect to the diameter of the stent. The results show a large and high intensity variation of data due to the strain gauge application. The variation is due to disturbances and flaws in the manufacturing process. On the other hand, one can see that the values for the radial forces of the segments for them different LGFs provide reasonable magnitudes. Some experiments also presents results similar to previous experiments. However, at the same time, no statistically significant conclusion can be drawn. The concept and the theory should work if the errors are changed. In summary, the proposal is to further develop the prototype and complement the experiment using finite element analysis.
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20

Little, Ryan King. "Does Revolution Breed Radicalism? An Analysis of the Stalled Revolution in Syria and the Radical Forces Since Unleashed." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5528.

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This thesis examines the turn to conflict in Syria during 2011 to see if it is revolutionary in nature and if so, why has it not succeeded? This thesis aims to analyze the anatomy of Syria's "revolution" in order to determine the causes behind the initial popular mobilization and transition to conflict. Then, further analysis of the essential elements of successful revolutionary movements will be undertaken to reveal what conditions remain unmet for Syria to culminate in a full revolutionary transformation. Special attention will be paid to the revolutionary Opposition itself, since, to date, it has proved unable to generate the power necessary to destroy the old order and rebuild a new system. The significant role of external intervention will also be addressed, since these forces have simultaneously helped cause the conflict, prolong the conflict and prop up the regime. Finally, the negative consequences of undertaking a revolutionary process, especially when left only partially complete, will be highlighted throughout the study. Syria's own "rise of the radicals," has manifested itself in the phenomenon of ISIL or ISIS, which has proven the strongest and most violent Opposition group to emerge from Syria's revolutionary environment.
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21

Swetnam, Thomas W. "Radial Growth Losses in Douglas-Fir and White Fir Caused by Western Spruce Budworm in Northern New Mexico: 1700-1983." Laboratory of Tree-Ring Research, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/302602.

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Final Report / Contract on 43-8371-4-628 / For: USDA, Forest Service, Southwestern Region<br>Regional outbreaks of western spruce budworms (Choristoneura occidentalis Freeman) have recurred at least three times in northern New Mexico since the early 1920's when the U. S. Forest Service first began systematic forest-pest surveys and documentation (Lessard 1975, U. S. Forest Service documents). The current outbreak was first noticed in a small area on the Taos Indian Reservation in 1974, and since then the defoliated areas have increased in New Mexico and Arizona to more than 370,000 acres of Federal, Indian, State and private lands (Linnane 1984). Losses in timber values can generally be ascribed to radial growth loss, height growth loss, topkilling, reduced regeneration, and mortality (Carlson et al. 1983, Fellin et al. 1983). A damage assessment project was initiated in 1978 and was aimed at obtaining measurements of some of these losses in budworm infested stands on the Carson National Forest, New Mexico (Holland and Lessard 1979). A large data base has subsequently been developed, including yearly measurements on topkilling, mortality, defoliation, and insect population changes (Stein 1980, 1981, Stein and McDonnell 1982, Rogers 1984). A growth assessment study was undertaken in 1982 to determine the feasibility of using dendrochronological methods to identify the timing of past outbreaks and to quantify radial growth losses associated with budworm defoliation (Swetnam 1984). Results of this work showed that three major outbreaks during the twentieth century were clearly visible in the tree-ring samples obtained from currently infested trees. The radial growth of host trees was corrected for age, climate and other non-budworm environmental effects, and then growth losses were computed as a percentage of expected growth (Swetnam 1984). Additional collections were obtained in 1984 in order to expand the scope of the radial growth study. The objectives included 1) assessment of a larger number of tree -ring samples, 2) comparison of radial growth losses between the two primary host species - Douglas-fir (Pseudotsuga menziesii) and white fir (Abies concolor), 3) comparison of radial growth losses between age classes, and 4) analysis of the relationship between yearly measurements of defoliation, insect populations and radial growth. This report summarizes the findings of the above analyses. Increment core samples from the 1982 collections are included here, therefore this report supersedes the earlier report (Swetnam 1984). Information is also presented on observations derived from the dated tree-ring series on the timing of occurrence of known and inferred spruce budworm outbreaks for the past 284 years (1700- 1983). This is the longest record of spruce budworm occurrence yet developed for western North America.
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22

Skyner, Rachael Elaine. "Hydrate crystal structures, radial distribution functions, and computing solubility." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/11746.

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Solubility prediction usually refers to prediction of the intrinsic aqueous solubility, which is the concentration of an unionised molecule in a saturated aqueous solution at thermodynamic equilibrium at a given temperature. Solubility is determined by structural and energetic components emanating from solid-phase structure and packing interactions, solute–solvent interactions, and structural reorganisation in solution. An overview of the most commonly used methods for solubility prediction is given in Chapter 1. In this thesis, we investigate various approaches to solubility prediction and solvation model development, based on informatics and incorporation of empirical and experimental data. These are of a knowledge-based nature, and specifically incorporate information from the Cambridge Structural Database (CSD). A common problem for solubility prediction is the computational cost associated with accurate models. This issue is usually addressed by use of machine learning and regression models, such as the General Solubility Equation (GSE). These types of models are investigated and discussed in Chapter 3, where we evaluate the reliability of the GSE for a set of structures covering a large area of chemical space. We find that molecular descriptors relating to specific atom or functional group counts in the solute molecule almost always appear in improved regression models. In accordance with the findings of Chapter 3, in Chapter 4 we investigate whether radial distribution functions (RDFs) calculated for atoms (defined according to their immediate chemical environment) with water from organic hydrate crystal structures may give a good indication of interactions applicable to the solution phase, and justify this by comparison of our own RDFs to neutron diffraction data for water and ice. We then apply our RDFs to the theory of the Reference Interaction Site Model (RISM) in Chapter 5, and produce novel models for the calculation of Hydration Free Energies (HFEs).
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Reinmann, Andrew B. "Effects of Harvesting on Nutrient Cycling, Red Spruce Radial Growth, and Dendrochemistry 30 Years after Harvesting in Northern Maine, USA." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/ReinmannAB2006.pdf.

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24

Wan, Chenchen. "Optical Tweezers Using Cylindrical Vector Beams." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1353515022.

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25

Perikala, Satish Kumar. "Evolution of Epitope regions in HIV genome: Delineating Selective Forces acting on Conformational and Linear Epitopes." [Kent, Ohio] : Kent State University, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1270735952.

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Thesis (M.S.)--Kent State University, 2010.<br>Title from PDF t.p. (viewed Apr. 28, 2010). Advisor: Helen Piontkivska. Keywords: Conformational Epitopes; Linear Epitopes; HIV; Selective Forces; synonymous changes; nonsynonymous changes; Radical changes; Conservative changes. Includes bibliographical references (p. 81-96).
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26

Bräker, Otto U., and Ernst Baumann. "Growth Reactions of Sub-Alpine Norway Spruce (Picea Abies (L.) Karst) Following One-Sided Light Exposure (Case Study at Davos "Lusiwald")." Tree-Ring Society, 2006. http://hdl.handle.net/10150/262646.

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In 1982, several rectangular openings were cut in a 100 year old sub-alpine Norway spruce forest stand to initiate regeneration at the Lusiwald site at Davos, Switzerland. The openings on the steep, north-facing slope created rapid changes to the environment of the border trees. Growth reactions of these border trees were compared and analysed with reference trees from the adjacent closed canopy stand in 1997. The radial growth pattern of the two data sets differed within the 14-year period since the openings were cut; the border trees showed growth releases. The growth reaction at the stem base was larger than at breast height. Changes in wind exposure may have influenced border trees to adapt their root systems. Sub-alpine Norway spruce stands aged around 100 years, which are usually considered slow-growing on a north aspect, still seem capable of reacting to greater resource availability such as sudden light changes.
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27

Belhadi, M'hamed. "Étude de machines à réluctance variable pour une application de traction électrique : réduction des ondulations de couple et des efforts radiaux." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112185.

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Le mémoire traite de la machine à réluctance variable en proposant d'une manière simultanée et du point de vue conception des solutions à ses deux inconvénients majeurs à savoir les ondulations de couple et les efforts radiaux. Les premières se propagent le long de la chaine de transmission diminuant ainsi le confort des usagers et les deuxièmes sont à l’origine d’une nuisance sonore. Dans une première partie et en s’intéressant à une structure axiale caractérisée par une faible force radiale, un bilan sur cette structure est donc établi. En effet, une configuration à deux stators et un rotor est la plus adéquate pour éventuellement remplacer la machine radiale de référence. Cette structure axiale est comparée à cette machine de référence après avoir établi des règles de passage d’une structure à une autre. Un premier passage est effectué en gardant le même encombrement et un deuxième passage en dimensionnant la machine axiale pour satisfaire le même cahier des charges que la machine radiale. Dans une deuxième partie, le travail s’oriente vers la modification de la structure radiale de la machine de référence et son optimisation. Plusieurs modifications sont proposées dont une structure avec une cale magnétique qui est la plus performante. Des optimisations géométriques à l’aide de l’algorithme génétique sur un point de fonctionnement sont ensuite effectuées pour remédier aux deux problèmes. A la fin, un récapitulatif de plusieurs structures optimisées est proposé pour servir de référence. Le choix de la machine la plus adéquate pourra donc être effectué en faisant un compromis entre la maximisation du couple, la réduction de ses ondulations et la réduction des efforts radiaux<br>This report deals with switched reluctance motor by offering design solutions to the drawbacks of torque ripples and radial forces in the same time. Torque ripples reduce the user comfort and radial forces are the origin of noise. In the first part, an axial structure characterized by low radial force is analysed. Indeed, an axial configuration with two stators and one rotor is the most appropriate to replace the reference radial machine. Ones the rules of passage from one structure to another are established, the axial structure is then compared to the reference one. A first passage is made by keeping the same volume and a second one by sizing the axial machine with the same specifications as the radial one. In the second part, the work concerns the modification of radial structure of the reference machine and its optimization. Several modifications are proposed including a structure with a magnetic wedge which is the most efficient. Geometric optimization using genetic algorithm are then performed on operating points to remedy the both problems. In the end, several optimized structures are proposed. The choice of the most suitable machine can be done by making a compromise between the torque maximization, reducing its ripples and reducing radial forces
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28

Campbell, Brian Jude Weimar Wendi Hannah. "Wrist extension counter-moment force effects on muscle activity of the ECR with gripping implications for lateral epicondylagia /." Auburn, Ala., 2006. http://repo.lib.auburn.edu/Send%206-15-07/CAMPBELL_BRIAN_6.pdf.

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29

Devillers, Emile. "Modélisation électromagnétique appliquée à la détermination des harmoniques de forces radiale et tangentielle dans les machines électriques en exploitant l’approche des sous-domaines." Thesis, Ecole centrale de Lille, 2018. http://www.theses.fr/2018ECLI0018/document.

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La présence d’harmoniques de forces électromagnétiques dans les machines électriques est généralement source de bruit acoustique et de vibrations (B&amp;V). Ce phénomène doit être considéré dès les premières phases de conception pour respecter les normes en matière de B&amp;V, en particulier dans le secteur automobile. Le niveau de B&amp;V s’obtient à partir d’une simulation multi-physique basée sur des modèles électromagnétiques, mécaniques et acoustiques, de préférence rapides et précis de manière à l’inclure le plus tôt possible dans la phase de conception. Cette thèse CIFRE est partie intégrante du programme de recherche interne de la société EOMYS ENGINEERING, qui développe et commercialise son logiciel MANATEE dédié à la simulation électromagnétique et vibroacoustique des machines électriques. Dans ce contexte de modélisation, cette thèse porte sur la méthode électromagnétique semi-analytique des sous-domaines pour le calcul des harmoniques de forces 2D dans l’entrefer d’une large variété de machines électriques, et se concentre particulièrement sur la Machine Synchrone à Aimant Permanents en Surface (MSAPS) et la machine asynchrone à cage d’écureuil. La thèse s’intéresse également à deux verrous scientifiques concernant la contribution des forces tangentielles au niveau de vibration global, et l’effet de modulation des dents qui apparaît dans les machines avec un nombre proche d’encoches et de pôles. A cet effet, un banc d’essai comprenant une machine bruyante particulière (une MSAPS avec 12 encoches et 10 pôles) et l’instrumentation nécessaire a été conçu et réalisé. Le banc d’essai vise enfin à comparer les différents modèles utilisés couramment dans les simulations B&amp;V<br>The presence of magnetic stress harmonics inside the electrical machine is generally responsible for vibrations and acoustic noise generation. This phenomenon is called e-NVH (Noise, Vibrations and Harshness due to electromagnetic excitations) and has to be considered in the machine design to meet with NVH standard requirements, especially in automotive applications. The e-NVH assertion requires a multiphysics simulation including electromagnetic, mechanical and acoustic models, which must be fast and accurate especially for early design stages. This industrial PhD thesis takes part of the internal research program of EOMYS ENGINEERING company, which develops and commercializes MANATEE software, dedicated to the e-NVH simulation of electrical machines. In this modeling context, the present thesis investigates and extends the semi-analytical electromagnetic model, called Subdomain Method (SDM), for the computation of two-dimensional airgap magnetic stress harmonics in various topologies of electrical machines, mainly focusing on Surface Permanent Magnet Synchronous Machines (SPMSMs) and Squirrel Cage Induction Machines (SCIMs). The thesis also investigates two scientific open questions concerning the contribution of circumferential excitations to the overall vibration level and the slotting modulation effect, which appears in electrical machines with a close number of poles and teeth. For this purpose, an experimental test rig including a particular noisy machine (a SPMSM with 12 slots and 10 poles) and appropriate sensors has been designed and built. The test rig also aims at benchmarking the different multiphysics models currently used in e-NVH simulation workflow
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30

Kamat, Sai Shyamsunder. "Analyzing Radial Basis Function Neural Networks for predicting anomalies in Intrusion Detection Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259187.

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In the 21st century, information is the new currency. With the omnipresence of devices connected to the internet, humanity can instantly avail any information. However, there are certain are cybercrime groups which steal the information. An Intrusion Detection System (IDS) monitors a network for suspicious activities and alerts its owner about an undesired intrusion. These commercial IDS’es react after detecting intrusion attempts. With the cyber attacks becoming increasingly complex, it is expensive to wait for the attacks to happen and respond later. It is crucial for network owners to employ IDS’es that preemptively differentiate a harmless data request from a malicious one. Machine Learning (ML) can solve this problem by recognizing patterns in internet traffic to predict the behaviour of network users. This project studies how effectively Radial Basis Function Neural Network (RBFN) with Deep Learning Architecture can impact intrusion detection. On the basis of the existing framework, it asks how well can an RBFN predict malicious intrusive attempts, especially when compared to contemporary detection practices.Here, an RBFN is a multi-layered neural network model that uses a radial basis function to transform input traffic data. Once transformed, it is possible to separate the various traffic data points using a single straight line in extradimensional space. The outcome of the project indicates that the proposed method is severely affected by limitations. E.g. the model needs to be fine tuned over several trials to achieve a desired accuracy. The results of the implementation show that RBFN is accurate at predicting various cyber attacks such as web attacks, infiltrations, brute force, SSH etc, and normal internet behaviour on an average 80% of the time. Other algorithms in identical testbed are more than 90% accurate. Despite the lower accuracy, RBFN model is more than 94% accurate at recording specific kinds of attacks such as Port Scans and BotNet malware. One possible solution is to restrict this model to predict only malware attacks and use different machine learning algorithm for other attacks.<br>I det 21: a århundradet är information den nya valutan. Med allnärvaro av enheter anslutna till internet har mänskligheten tillgång till information inom ett ögonblick. Det finns dock vissa grupper som använder metoder för att stjäla information för personlig vinst via internet. Ett intrångsdetekteringssystem (IDS) övervakar ett nätverk för misstänkta aktiviteter och varnar dess ägare om ett oönskat intrång skett. Kommersiella IDS reagerar efter detekteringen av ett intrångsförsök. Angreppen blir alltmer komplexa och det kan vara dyrt att vänta på att attackerna ska ske för att reagera senare. Det är avgörande för nätverksägare att använda IDS:er som på ett förebyggande sätt kan skilja på oskadlig dataanvändning från skadlig. Maskininlärning kan lösa detta problem. Den kan analysera all befintliga data om internettrafik, känna igen mönster och förutse användarnas beteende. Detta projekt syftar till att studera hur effektivt Radial Basis Function Neural Networks (RBFN) med Djupinlärnings arkitektur kan påverka intrångsdetektering. Från detta perspektiv ställs frågan hur väl en RBFN kan förutsäga skadliga intrångsförsök, särskilt i jämförelse med befintliga detektionsmetoder.Här är RBFN definierad som en flera-lagers neuralt nätverksmodell som använder en radiell grundfunktion för att omvandla data till linjärt separerbar. Efter en undersökning av modern litteratur och lokalisering av ett namngivet dataset användes kvantitativ forskningsmetodik med prestanda indikatorer för att utvärdera RBFN: s prestanda. En Random Forest Classifier algorithm användes också för jämförelse. Resultaten erhölls efter en serie finjusteringar av parametrar på modellerna. Resultaten visar att RBFN är korrekt när den förutsäger avvikande internetbeteende i genomsnitt 80% av tiden. Andra algoritmer i litteraturen beskrivs som mer än 90% korrekta. Den föreslagna RBFN-modellen är emellertid mycket exakt när man registrerar specifika typer av attacker som Port Scans och BotNet malware. Resultatet av projektet visar att den föreslagna metoden är allvarligt påverkad av begränsningar. T.ex. så behöver modellen finjusteras över flera försök för att uppnå önskad noggrannhet. En möjlig lösning är att begränsa denna modell till att endast förutsäga malware-attacker och använda andra maskininlärnings-algoritmer för andra attacker.
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31

McQuillan, Shane. "Above and Below Ground Assessment of Pinus radiate." Thesis, University of Canterbury. School of Forestry, 2013. http://hdl.handle.net/10092/9897.

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A comparison of above ground forest metrics with below ground soil CO₂ respiration was carried out in an attempt to reveal if any correlations exist. Above ground measurements of 2720 clonally propagated trees were taken assessing the silvicultural treatments of stocking, herbicide and fertiliser. These were compared to 480 below ground soil CO₂ respiration measurements. Using measurements of mean height, mean dbh and basal area the data was analysed and returned significant results for mean dbh and the interactions of herbicide and clones, and stocking and herbicide. Mean height returned a significant result for the interaction of stocking and herbicide. Below ground measurements showed an interaction between ripping and stocking; however these results were not ratified by the above ground results. Overall the results were encouraging and should aid in future experiments that seek to understand what effect above ground treatments have on below ground CO₂ activity.
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32

Gundogmus, Omer. "SIMULTANEOUS TORQUE RIPPLE AND ACOUSTIC NOISE MITIGATION IN SWITCH RELUCTANCE MACHINES." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1579790717180753.

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33

Butcher, Matthew James. "Adsorption and manipulation of doped fullerenes on silicon surfaces." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325717.

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34

Anhê, Junior Sérgio Antônio [UNESP]. "Investigação numérica e experimental do escoamento em válvulas de compressores herméticos." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/88864.

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Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-28Bitstream added on 2014-06-13T20:30:31Z : No. of bitstreams: 1 anhejunior_sa_me_ilha.pdf: 2550289 bytes, checksum: 4299d702522bdb3a4b51de625099c77e (MD5)<br>Fundação de Ensino Pesquisa e Extensão de Ilha Solteira (FEPISA)<br>O presente trabalho refere-se à investigação experimental e numérica do escoamento em difusores radiais, que são usados como modelos de representação de sistemas de válvulas de compressores de refrigeração. Uma bancada experimental é projetada, construída e validada para medir a distribuição de pressão, sobre o disco frontal de um difusor radial de razão de diâmetro 3, para números de Reynolds de 1500 a 9000 e afastamento entre os discos frontal e anterior variando de 0,415mm a 0,705mm aproximadamente. Paralelamente, desenvolve-se um código computacional, baseado na metodologia de Volumes Finitos para malhas desencontradas, para simular o escoamento na geometria do difusor radial. O código computacional é primeiramente validado por meio dos resultados experimentais obtidos da bancada construída. Após sua validação, o código é usado para analisar o escoamento em um difusor de razão de diâmetro igual a 1,4, para números de Reynolds variando de 500 a 2500 e afastamento entre discos na fixa de 0,125 a 1,0mm. Os resultados numéricos mostram o surgimento de recirculação extendendo-se em toda região do difusor. Além disso, os resultados de perfil de pressão sobre o disco frontal fornecem forças e quedas totais de pressão no difusor que aumentam com o número de Reynolds e afastamento entre disco. Esse comportamento produz um ponto de mínima área efetiva de força localizado na faixa de , para números de Reynolds variando de 500 a 1500. Para número de Reynolds mais elevados, , a área efetiva de força sempre aumenta com o aumento do afastamento entre discos. A área efetiva de escoamento, outro parâmetro de interesse para a simulação do compressor, apresenta um crescimento linear com o afastamento entre discos, independentemente do número de Reynolds avaliado.<br>In this work, an experimental and numerical investigation of the flow in radial diffusers representing the valve system of refrigeration compressor is accomplished. An experimental bench is designed, build, and validated allowing the measurement of the pressure distribution on the frontal disk surface of a radial diffuser with diameter ratio equal to 3, for Reynolds number varying from 1500 to 9000 and distances between disks in the ranges of 0.415 to 0.705mm. In addition, a computational code based on the Finite Volume Methodology for staggered mesh is developed in order to simulate the flow though the radial diffuser. The computational code is firstly validated by using the experimental data obtained from the experimental bench. After its validation, the code is used for analyzing the flow through a radial diffuser with diameter ratio equal to 1.4, for Reynolds numbers varying from 500 to 2500 and distance between disks in the range of 0.125 a 1.0 mm. The numerical results showed recirculation regions extending through the whole diffuser for the majority of the analyzed cases. The pressure profiles on the frontal disk surface produce forces and total pressure drops through the diffuser that increase with both Reynolds number and distance between disks. There is a minimum effective force area in the range of , for Reynolds numbers varying from 500 a 1500. For higher Reynolds numbers, , the effective force area always increases for increasing distance between disks. The effective flow area, another parameter used for simulating the compressor, increases linearly with the distance between disks, independently of the Reynolds number.
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35

Slui, Benjamin Thomas. "The effect of plot co-registration error on the strength of regression between LiDAR canopy metrics and total standing volume in a Pinus radiata forest." Thesis, University of Canterbury. School of Forestry, 2014. http://hdl.handle.net/10092/10460.

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Background: The objective of this study was to verify the effect that plot locational errors, termed plot co-registration errors, have on the strength of regression between LiDAR canopy metrics and the measured total standing volume (TSV) of plots in a Pinus radiata forest. Methods: A 737 hectare plantation of mature Pinus radiata located in Northern Hawkes Bay was selected for the study. This forest had been measured in a pre-harvest inventory and had aerial LiDAR assessment. The location of plots was verified using a survey-grade GPS. Least square linear regression models were developed to predict TSV from LiDAR canopy metrics for a sample of 204 plots. The regression strength, accuracy and bias was compared for models developed using either the actual (verified) or the incorrect (intended) locations for these plots. The change to the LiDAR canopy metrics after the plot co-registration errors was also established. Results: The plot co-registration error in the sample ranged from 0.7 m to 70.3 m, with an average linear spatial error of 10.6 m. The plot co-registration errors substantially reduced the strength of regression between LiDAR canopy metrics and TSV, as the model developed from the actual plot locations had an R2 of 44%, while the model developed from the incorrect plot locations had an R2 of 19%. The greatest reductions in model strength occurred when there was less than a 60% overlap between the plots defined by correct and incorrect locations. Higher plot co-registration errors also caused significant changes to the height and density LiDAR canopy metrics that were used in the regression models. The lower percentile elevation LiDAR metrics were more sensitive to plot co- registration errors, compared to higher percentile metrics. Conclusion: Plot co-registration errors have a significant effect on the strength of regressions formed between TSV and LiDAR canopy metrics. This indicates that accurate measurements of plot locations are necessary to fully utilise LiDAR for inventory purposes in forests of Pinus radiata.
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36

Harden, Nicholas C. "Forays into magnetic and electronic interactions, near infrared dyes and luminescence." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302162.

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37

Van, Zyl Salmon Johannes. "Biomass potential and nutrient export of mature pinus radiata in the southern Cape region of South Africa." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/4321.

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South Africa lags behind the rest of the world with regard to the availability of allometric biomass information. There is a complete lack of site specific allometric data for Pinus radiata in the southern Cape region, impeding investment in the renewable energy sector. This shortcoming was addressed by developing up-scalable, single tree biomass models. These models quantify the aboveground biomass of rotation age P. radiata grown in the southern Cape across a range of site conditions. The models use diameter at breast height (DBH) to predict the aboveground component biomass. A nutrient loss risk potential was assigned to each biomass component. Nineteen trees were destructively harvested using a full fresh weight sampling approach. Basic density was determined using a water displacement method, while Newton’s volume equation was used for stemwood volume determination. Log linear models were simultaneously regressed through seemingly unrelated regression (SUR) using the “Systemfit” R statistical package to force component additivity. A categorical variable was applied to the models, grouping the data into two Site Index (SI) based categories, namely “Low” SI and “Medium to High” SI, to account for inter-site variability. The corrected Akaike Information Criteria (AICc) and coefficient of determination (R2) was used to determine the goodness of fit of the models. The McElroy R2 for the SUR system was 0.95. Biomass models were developed that are able to predict various tree component masses at high levels of certainty within site and stand attribute ranges similar to this study. The importance of accurate, site specific wood basic density was demonstrated by its substantial weighting on stem and hence total biomass. Results showed that the stemwood mean basic density range was between 503 kg m-3 and 517 kg m-3 for the “Low” SI sites and 458 kg m-3 for the “Medium to High” SI sites. Site quality can have a major impact on the models, particularly on poorer sites where stemwood production is proportionally less than other tree components. Total aboveground biomass was estimated to range between 58.61 odt ha-1 and 70.85 odt ha-1 for “Low” SI sites, and 185.31 odt ha-1 to 266.58 odt ha-1 for “Medium to High” SI sites. Stemwood biomass accounted for 65% of the total aboveground biomass for “Low” SI sites and 70% for “Medium to High” SI sites.
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Венгер, Сергій Вікторович Venger Serhii. "Інформаційно-вимірювальна система пристрою для вимірювання сил різання при обробці похилих отворів на свердлильних верстатах". Master's thesis, ТНТУ ім. І. Пулюя, 2021. http://elartu.tntu.edu.ua/handle/lib/36918.

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: В даній кваліфікаційній роботі здійснюється розробка та дослідження інформаційно- вимірювальна система пристрою для вимірювання сил різання при обробці похилих отворів на свердлильних верстатах. В роботі описано схему функціональну даного приладу, проведено розрахунок основних елементів при різних видах навантажень та проведено розрахунок похибки приладу. Проведено дослідження характеристик процесу передачі та обробки сигналу, створено модель математичну, що описує залежність показів давачів тензометричних від навантаження. Описано роботу електричної схеми, зроблено розрахунок її елементів, та розроблено схему керування з описом роботи та формуванням алгоритму роботи електричної схеми.<br>In this qualification work the development and research of information-measuring system of the device for measurement of forces of cutting at processing of inclined holes on drilling machines is carried out. This paper describes the functional diagram of this device, calculates the basic elements at the different types of loads and the calculation of the device error of the device is made. A study of the characteristics of the process of signal transmission and processing created a mathematical model that describes the dependence of the readings of strain gauges on the load. The work of the electric circuit is described, the calculation of its elements is made, and the control scheme with the description of work and formation of algorithm of work of the electric circuit is developed.<br>ВСТУП 1 АНАЛІТИЧНА ЧАСТИНА 1.1 Аналіз питання, яке розглядаємо 1.2 Види динамометрів 2 ОСНОВНА ЧАСТИНА 2.1 Опис схеми функціональної приладу 2.2 Розрахунок елементів механічної конструкції 2.2.1 Розрахунок тензобалки навантаження осі динамометра 2.2.2 Розрахунок тензобалки навантаження радіального для динамометра 2.2.3 Розрахунок тензобалки моменту крутного для динамометра 2.2.4 Розрахунок похибки вимірювання динамометра 3 НАУКОВО-ДОСЛІДНА ЧАСТИНА 3.1 Дослідження характеристик процесу передачі та обробки сигналу мікросхемою AD598 3.2 Дослідження залежності показів тензодатчика від осьового навантаження 4 СПЕЦІАЛЬНА ЧАСТИНА 4.1 Опис роботи електричної схеми та розрахунок її елементів 4.2 Алгоритм роботи електричної схеми 4.3 Схема керування пристроєм та опис принципу роботи 4.4 Розробка принципової схеми 4.5 Дослідження залежності показів тензодатчика від осьового навантаження 4.6 Бюджет для визначених похибок вимірювальних каналів 5 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ ВИСНОВКИ ПЕРЕЛІК ПОСИЛАНЬ ДОДАТКИ
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39

La, Delfa Patricio. "Contribution à la conception silencieuse par démarches directe et inverse de machines synchrones à aimants permanents et bobinage dentaire." Thesis, Ecole centrale de Lille, 2017. http://www.theses.fr/2017ECLI0036/document.

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Cette thèse porte sur la conception silencieuse par démarches inverses de machines synchrones à aimants permanents dotées de bobinages dentaires. Notre travail se focalise sur l’analyse des raies de forces radiales à l’origine du bruit magnétique. En premier lieu, un modèle direct électromagnétique, nous a permis de déterminer le spectre spatio-temporel de la force radiale dans l’entrefer. Ce dernier nous offre la possibilité d’obtenir pas à pas et de manière analytique l’induction radiale dans l’entrefer, résultat du produit de la force magnétomotrice totale et de la perméance d’entrefer globale. Plusieurs machines dotées d’un bobinage dentaire et distribué ont été évaluées, comparées à des simulations par éléments finis et corroborés par une analyse modale opérationnelle sur un prototype existant au laboratoire. Puis la démarche inverse de conception est abordée par le biais de deux outils « analytiques prédictifs » donnant les origines des ordres faibles spatio-temporels de la force radiale dans l’entrefer. Enfin, la résolution du problème inverse est conduite au moyen d’une boucle itérative d’optimisation donnant parmi un échantillon de solutions, une fonction de bobinage, visant à atténuer ou supprimer une raie potentiellement risquée en termes de nuisances acoustiques<br>This thesis deals the quiet design by inverses approaches of synchronous machines with permanent magnets concentrated windings. Our work focuses on the analysis of magnetic noise origin of air gap radial force orders. Firstly a direct electromagnetic model allowed us to determine the spatio-temporal spectrum of air gap radial pressure. The latter offers us the possibility of obtaining step by step and in an analytical way the radial induction in the gap, result of the product of the total magnetomotive force and global air gap permeance. Several machines equipped with a concentrated winding and distributed were evaluated, compared to simulations by finite elements and corroborated by an operational deflection shape on an existing prototype in the laboratory. In the second time two inverse approaches named predictive methodology identified the radial pressure low order origin. Finally, the resolution of the inverse problem is carried out by means of an iterative optimization loop giving among a sample of solutions, a winding function, aimed at attenuating or eliminating a potential risky line in terms of acoustic nuisances
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40

Nair, Hema. "A study of intra-ring checking and xylogenesis in Pinus radiata D.Don." Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1325.

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Pinus radiata is the dominant species of the plantations forests in New Zealand. The forest industry in New Zealand is heavily dependant on it. However, Pinus radiata can develop wood quality flaw called 'intra-ring checking'. The checks or splits appear in wood during kiln drying and usually affect the earlywood region of the wood. It lowers value of appearance grade timber leading to huge economic loses for the forest industry. This thesis presents a study that was undertaken as a part of ongoing collaborative work that is being carried out to understand wood quality issues in Pinus radiata, with a vision of improving its wood quality. This study was a part of that effort and was conducted with an aim to gain an insight into intra-ring checking, and the process of xylogenesis in Pinus radiata. The investigations for this study were carried out in two steps. The first step was to understand intra-ring checking. The location of intra-ring checking was determined by observing the checks using various microscopy techniques. Scanning electron microscopy confirmed that checking was as an intercell failure that usually occurs at the cm1/S1 boundary. A comparative study was also conducted to see if the checked wood had some inherent properties that made it more susceptible to checking. It was found that checking could be influenced by tracheid geometry and cell wall thickness. If the wood had large tracheids with thin walls, it was more likely to develop checks during drying. Lignin distribution in the cell wall layers was also seen to play an important role in checking. Lower lignin levels and disruption in the pattern of lignification of the cell wall layers increased the tendency of the wood to develop checks. Similarly, it the tracheids have larger pits then their tendency to check increases. Structural features that disrupt the uniformity of the interlocking pattern of the tracheid such as rays and resin canals could also play a role in checking. Checked wood tends to have more surface area occupied by ray tissue. However, resin canals do not seem to be directly involved in checking, though their arrangement could indicate disturbances during xylogenesis. The second step was to understand the process of xylogenesis in Pinus radiata especially with respect to the influence of auxin and boron on it. Nutrient and organ culture methods were manipulated and successfully used to study xylogenesis. An exhaustive comparative study was carried out to observe and measure selected wood properties. Microscopy and image analysis revealed that auxin and boron changes in the medium led to the alterations in the cell division, expansion and lignification. However, the analysis of the measurements and the observations displayed complex 'between-tree' and 'within-culture variations'. Clear trends did not emerge from the analysis hence, a confident conclusion on the association between auxin, boron and lignification could not be drawn from this organ culture study. The study has added to the knowledge about checking and wood properties associated with it. A new tool of organ culture had been established that can hlep future research on the process of xylogenesis in Pinus radiata.
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Merlyn, Teri, and n/a. "Writing Revolution: The British Radical Literary Tradition as the Seminal Force in the Development of Adult Education, its Australian Context, and the Life and Work of Eric Lambert." Griffith University. School of Vocational, Technology and Arts Education, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040616.131738.

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This thesis tells the story of an historical tradition of radical literacy and literature that is defined as the British radical literary tradition. It takes the meaning of literature at its broadest understanding and identifies the literary and educational relations of what E.P. Thompson terms 'the making of the English working class' through its struggle for literacy and freedom. The study traces the developing dialectic of literary radicalism and the emergent hegemony of capitalism through the dissemination of radical ideas in literature and a groundswell of public literacy. The proposed radical tradition is defined by the oppositional stance of its participants, from the radical intellectual's critical texts to the striving for literacy and access to literature by working class people. This oppositional discourse emerged in the fourteenth century concomitant with nascent capitalism and has its literary origins in utopian vision. This nascent utopian imagination conceived a democratic socialism that underpinned the character of much of the following oppositional discourse. The thesis establishes the nexus of the oppositional discourse as a radical literary tradition and the earliest instances of adult education in autodidacticism and informal adult education. The ascent of middle class power through the industrial revolution is shadowed by the corresponding descent of the working class into poverty. Concomitant with this social polarisation is the phenomena of working class literary agency as the means to political and economic agency. While Protestant dissenting groups such as the Diggers and Levellers were revolutionary activists, it was Methodism that formed a bulwark against revolution. Yet it was their emphasis on self-improvement that contributed to an increasingly literate populace. Radical texts produced and disseminated by individuals and organisations and read by autodidactics and informal reading groups are seminal in the formation of a working class identity. Spearheaded by the Chartist movement, education became a central ethic of working class politics and the civil struggle for economic and political justice throughout the nineteenth and well into the twentieth centuries. The avant garde movements of the early twentieth century are analysed as a strand of this tradition. The narrative of the thesis then moves to the penal colony of Australia and explores the radical literary tradition's development there. Early colonial culture is seen as having a strong impetus towards a developing a native literary expression of the new land. Where conservative colonial literature struggled to differentiate itself from formal British literary models, the radical heritage and its utopian vision of a working man's paradise gave definitive expression to the Australian experience. This expression was strongly influenced by Chartist ideals. The British radical literary tradition is thus seen to have had a dominant influence in the development of a native radical literary tradition that strove to identify the national character. Socialist thought developed in Australia in concert with that in the parent culture, and anarchist and libertarian trends found a ready home amongst independent minded colonials. Yet, in preventing the formation of a native aristocracy the small radical population made a compromise with liberalism that saw a decidedly conservative streak develop in the early labour movement. There were little in the way of sophisticated radical literary offerings at first, but from the mid-nineteenth century a vanguard of radicals produced a thriving native press and other fugitive text forms. At the turn of the century the native radical literary tradition was vibrantly diverse, with a definitive style that claimed literary ownership of the Australian character. However, exhausted by the battles over WWI conscription and isolated by censorship, the Communist Party of the Soviet Union was able to subsume the vanguard position from the socialists. The Party laid claim to the Australian radical literary tradition, at once both strengthening it with the discipline of a Marxist ideology and diminishing its independence and diversity. Party literary theory centred upon the issue of class, developing a doctrine of socialist realism that communist writers were expected to practice. How well a writer adhered to socialist realist principles became a measure of their class position and loyalty. Drawing more from primary sources, the thesis develops an analysis of the intellectual development of the Australian post-WWII writer Eric Lambert through his experience of class instability during Depression and war. The study examines Lambert's decision to join the Party and his literary response to his experiences of war, the Party, the turmoil of 1956 and life after the Party. Lambert's body of work is then analysed as the unintentional memoir of a writer working as an adult educator in the radical literary tradition. Lambert's struggles, for artistic independence within the narrow precepts of Party dogma and with class tensions, were common amongst intellectuals committed to the communist cause. Like many of his peers, Lambert resigned from the Party at the end of 1956 and suffered a period of ideological vacuum. However, he continued to write as a Marxian educator, seeking to reveal that which makes us human in the humanity of ordinary people. It is concluded that, while the Party did much to foster disciplined cohesion, the mutual distrust it generated amongst its intellectuals suppressed the independent thought that had kept the radical literary tradition alive. Although the Party developed an ideological strength within the radical literary tradition, its dominance over thirty years and subsequent fall from grace acted to fragment and discredit that centuries-old tradition which it subsumed. An argument is made for a reinvestment of the centrality of the radical literary tradition in the education of adults for the maintenance of social justice and the democratic project.
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42

Çakir, Pinar. "Molecularly imprinted polymer nanostructures by controlled / living radical polymerization with multi-iniferters." Compiègne, 2012. http://www.theses.fr/2012COMP2018.

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Les polymères à empreintes moléculaires (MIPs) sont des matériaux synthétiques contenant des cavités capables de reconnaître spécifiquement une molécule cible. Ils se présentent comme une alternative intéressante face aux anticorps biologiques en raison de leur meilleure stabilité chimique et physique, leur meilleure disponibilité et leur moindre coût. Traditionnellement, les MIPs sont synthétisés par polymérisation de monolithes, qui sont ensuite broyés mécaniquement, engendrant des particules de taille micrométrique et de formes irrégulières. Durant ces dernières années, de nombreuses techniques de polymérisation ont été développées afin d’obtenir des particules MIP sphériques de tailles micro et nanométriques, et plus particulièrement des nanogels quasi-solubles. Dans l’optique d’une application en biologie, des tailles de quelques nanomètres - de l’ordre de grandeur de la taille des protéines – sont souhaitées, ce qui pose un réel défi pour leur synthèse, car la faible densité du matériau (une particule ne consiste que de quelques chaines de polymère) s'oppose à l'impression d'une mémoire moléculaire. Nous avons développé une nouvelle approche de synthèse de MIP nanogels dont la taille est proche de celle des anticorps naturels. Notre stratégie est basée sur l’utilisation d’un nouveau type d'amorceur pour la polymérisation radicalaire contrôlée comprenant des fonctions iniferter multiples attachées à un noyau dendritique. Cela permet de générer une concentration localement élevée de radicaux et ainsi, d'obtenir des nanogels de polymère dont la densité est augmentée. Ces travaux de thèse ont conduit à l’obtention des nanogels de MIP de 17 nm de diamètre avec un effet impression appréciable, une bonne affinité pour la cible, le beta-antagoniste propranolol, et une sélectivité moléculaire prononcée. En plus de la synthèse des nanogels solubles de MIP, des motifs de MIP micro et nanostructurés ont été greffés sur des surfaces planes de silicium. Le multiiniferter a été imprimé à la surface par lithographie douce, et fixé chimiquement par son groupement carboxyle central. Les MIPs ont ensuite été synthétisés par une approche « bottom up », caractérisés par spectroscopie d'émission optique, la spectroscopie Raman et la microscopie à force atomique, et la reconnaissance moléculaire de la cible a été visualisée par microscopie de fluorescence. Ces nouveaux matériaux, nanogels et surfaces imprimées offrent de nombreuses perspectives pour la détection par biocapteurs et biopuces, en particulier dans le domaine du biomédical<br>Molecularly imprinted polymers (MIPs) are synthetic materials with specific recognition properties for target molecules. They are considered an alternative to antibodies and are characterized by a higher chemical and physical stability, better availability and lower cost. Historically, MIPs were synthesized as bulk monoliths that were subsequently broken down mechanically in order to form particles of a size in the micrometer range, with irregular shapes. During the last decade, research has focused on the direct synthesis of spherical MIP micro and nanoparticles, and, more recently, on protein-sized, quasi-soluble MIP nanogels in order to widen the application range of MIPs in the biological field. The main difficulty of synthesizing MIPs with diameters in the low nm region is the low density of the resulting polymer network consisting only of a few polymer chains, which makes it difficult to imprint and maintain a molecular memory. In this thesis, we propose an original approach to the synthesis of quasisoluble MIP nanogels with a size in the low nm range, close to that of real antibodies. The proposed procedure involves a new type of initiator for controlled/living radical polymerization, based on multiple iniferter moieties attached to a dendritic core. This allows for the generation of a higher local radical density, and thus for the synthesis of denser nanogels. By using this strategy, MIP Nanogels of 17 nm size with an appreciable molecular imprinting effect, a good affinity for the target molecule, the chiral drug propranolol, and a good selectivity were obtained. In addition, these multiiniferters were also used for the bottom-up synthesis of thin MIP patterns on silicon wafers, by surface-initiated polymerization. The multi-iniferter was printed on to the surface by soft lithography and chemically attached through its carboxyl-functionalized core, followed by the in-situ synthesis of the MIP. Well defined MIP patterns were obtained, which were characterized by optical emission spectroscopy, Raman spectroscopy, atomic force microscopy, and the specific binding of the target molecule was visualized by fluorescence microscopy. We believe that the synthesis, in solution and at surfaces, of protein-size MIP nanogels with specific recognition properties will provide new opportunities for biosensors and biochips technologies in biomedical applications
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43

Wells, Karen E. "Development of a Laboratory Protocol for the Micropropagation of Monterey Pines (Pinus Radiata), Año Nuevo Stand." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/76.

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Monterey pine (Pinus radiata), a native tree to California and two Mexican islands, is important both ecologically and economically. Outside native stands, Monterey pines are grown for landscaping in California and on plantations around the world. Pitch canker, a disease caused by the fungus Gibberella circinata Nirenberg & O’Donnell (Fusarium circinatum Nirenberg and O'Donnell) is threatening the survival of Monterey pines. The disease currently affects Monterey pines in many parts of the world including the native stands. No effective chemical or biological control is available but some Monterey pines show resistance to the disease. The purpose of this project was to develop a working protocol for producing genetic clones of the resistant pines through micropropagation. These genetic clones will be used for outplanting in places outside the native stands for ornamental and plantation purposes. This project analyzes the results of ten trials with varied parameters and bases the final protocol on the parameters used in the trial that induces the growth of new shoots. The final protocol developed in this project describes, step-by-step, the media preparation for the initiation, plant material collection, surface sterilization of plant material, plating in media and initiation of shoots on explants. The protocol calls for collecting shoot tips with hardened buds that have not yet elongated, then washing the shoot tips in sterile water with Tween 20 for 15 minutes. The shoots tips are then surface sterilized in a 50% bleach solution for 20 minutes. The explants are broken into disks (to minimize damage to the cells) by inserting the tip of a scalpel and tilting it slightly. The initiation media shown to induce growth consists of ½ strength LePoivre basal salt mixture, 5mg/L benzylaminopurine, 3% sucrose and 0.8% agar and is adjusted to a pH of 5.7, then autoclaved for 20 minutes. The explants are inserted into solidified media and incubated in a growth chamber programmed for 16 hours of light and 8 hours of dark with temperatures of 27ºC and 22ºC and light irradiance of 80µEm-2s-1. After 1 month the protocol calls for transferring the growing shoots to elongation media with full LP basal salts and transferring every month. When the number of desired shoots has been reached the forthcoming protocol for rooting can be followed.
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44

Koutný, Luděk. "Snížení radiální síly odstředivých čerpadel." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228759.

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This diploma thesis deals with problematics of the radial force effect on the runner and possibilities of the force reduction. Some pump modifications were proposed and changes of radial force magnitude in reverse blocking state and optimal flow state were examined in consequence. Following investigation was focused on the new modifications regarding to the pump efficiency and its characteristics stability. All results were carried out using the Solidworks, the Fluent and the Microsoft Excel software.
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45

Gaffney, Charles. "Topographic microclimate influence on radial growth responses of sugar maple (acer saccharum marsh.) and white oak (quercus alba L.) to regional climate stresses." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941379.

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Tree-rings were analyzed to assess the relative importance of slope position and aspect as determinants of the climate-sensitivity of sugar maple and white oak radial growth. Tree size, crown condition, forest and soil composition, and site indices were assessed to document environmental differences between site-types and to verify similarity of stands within the same site-type. Climate-sensitivity was assessed using mean between-tree correlation, principal components analysis, mean sensitivity, regression analysis, and analysis of radial growth decline after severe drought. Ecological differences were found between high and low sites on north and south facing aspects. Sugar maple did not exhibit greater climate-sensitivity than white oak. Both species showed greater climate-sensitivity on upper and south-facing slopes.<br>Department of Biology
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46

Nováková, Naděžda. "Dynamické radiální síly působící na oběžné kolo odstředivého čerpadla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230329.

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This thesis deals with the radial forces acting on the impeller of a centrifugal pump. It focuses on the centrifugal pump type BETA 26. It addresses forces acting on the pump shaft. These forces are converted into the impeller. The most extensive part of this thesis is devoted to the experimental measurement and evaluation. The results are summarized and processed graphically.
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47

Fischer, Phillip Murray. "δ13C as indicator of soil water availability and drought stress in Pinus radiata stands in South Africa". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6588.

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Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 2011.<br>ENGLISH ABSTRACT: This study investigated the use of carbon isotopes as a potential measure for water availability and drought stress in Pinus radiata in the Western and Southern Cape, South Africa. An understanding of water availability and its variation in space is fundamental to the implementation of increasingly site-specific management regimes that have the potential to greatly improve productivity across sites in the region. Fifteen plantation compartments situated on water shedding sites were identified where good weather data existed and a water balance model could be run. In addition, late wood samples were analysed from four co-dominant trees in the same stand to determine the δ13C values of five tree rings, each representing a specific growth year before first thinning. Detailed water balances were constructed for each trial site and drought stress indicators (a) relative canopy conductance (after Granier et al., 2000) and (b) the ratio of actual to potential evapotranspiration (supply / demand ratio), were related to δ13C values in latewood. Maximum available soil water ranged from 52 to 313 mm across trial sites. The water balance model used adequately described soil water availability throughout each growing season and indicated that stand stress due to the lack of available soil water mainly occurred during the summer months of the study period (November to April). The supply / demand ratio for this period as well as the relative canopy conductance proved to be good measures of drought stress. The six-month supply demand ratio (calculated for the period November to April) ranged from 0.04 to nearly 1 (winter rainfall zone) and 0.35 to 1 (all-year rainfall zone) and were strongly related to δ13C values (p < 0.001; r2 = 0.7822). It appears that using δ13C values, it may be possible to classify sites into three water availability classes. This classification may assist in the implementation of intensive silvicultural operations on an increasingly site-specific basis. Where sites are enriched with water from lateral flow or upslope positions, δ13C may be the only reliable technique to quantify soil water availability.<br>AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die gebruik van koolstof isotope as 'n moontlike maatstaf vir die beskikbaarheid van water en droogtestremming in Pinus radiata in die Wes-en Suid-Kaap, Suid-Afrika. 'n Begrip van die beskikbaarheid van water en die ruimtelike variasie daarvan is fundamenteel vir die implementering van groeiplek-spesifieke bestuur sisteem wat die potensiaal het om baie verbeterde produktiwiteit oor persele in die streek teweeg te bring. Vyftien plantasievakke, geleë op waterskeidingsterreine is geïdentifiseer waar goeie weer data bestaan en 'n water balans model uitgevoer kon word. Daarmee saam is laathout monsters vanuit vier ko-dominante bome in dieselfde kompartement geanaliseer en die δ13C waardes van laathout in vyf jaarringe bepaal wat elk 'n spesifieke jaar van groei voor die eerste dunning verteenwoordig. Gedetailleerde water balanse is vir elke proef perseel bereken en aanwysers van droogtestremming, nl.: (a) relatiewe kroon geleiding (na Granier et al., 2000) en (b) die verhouding van die werklike teenoor potensiële evapotranspirasie (vraag / aanbod verhouding) is gekorreleer met 13C waardes in laat hout. Die maksimum hoeveelheid water beskikbaar op die verskeie proefpersele wissel van 52 tot 313 mm. Die water balans model wat gebruik is beskryf die beskikbare grondwater met genoegsame akkuraatheid. vir die hele groeiseisoen. Die model dui ook aan dat die kompartemente droogtestremming as gevolg van die gebrek aan beskikbare grond water ervaar gedurende die somer maande van die studie tydperk (November tot April). Die vraag / aanbod verhouding vir hierdie tydperk, asook die relatiewe kroon geleiding is geskik om as maatstawwe van droogtestremming gebruik te word. Die vraag / aanbod verhouding (bereken vir die tydperk November tot April) het gewissel van 0,04 tot byna 1 (Winter reënval gebied) en 0,35 tot 1 (die heel jaar reënval sone) en is sterk verwant aan 13C waardes (p <0,001; r2 = 0,7822). Dit blyk dat met die gebruik van δ13C waardes, dit moontlik kan wees om kompartemente te klassifiseer in drie klasse van water beskikbaarheid. Hierdie klassifikasie kan help met die implementering van intensiewe boskultuur bedrywighede op 'n meer vak-spesifieke basis. Waar vakkeverryk is met water vanuit laterale vloei of hoër liggende posisies, mag δ13C dalk die enigste betroubare tegniek wees om die beskikbaarheid van water te kwantifiseer.
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48

Tallieu, Clara. "État sanitaire et croissance radiale des arbres : Analyse spatiale et temporelle des données du réseau systématique de suivi des dommages forestiers." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0185.

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Depuis 30 ans, les mesures annuelles de déficit foliaire des arbres sur la partie française du réseau européen de suivi des dommages forestiers (ICP Forests, niveau 1), constituent la base du suivi de l’état de santé des forêts. Pourtant, l’utilisation du déficit foliaire comme indicateur de l’état de santé de l’arbre est régulièrement remise en cause pour des raisons méthodologiques mais aussi en raison du manque de connaissances sur le déterminisme du déficit foliaire et de son impact fonctionnel sur l’arbre. Dans ce contexte, au travers des notations de déficit foliaire de 9 essences (feuillues et résineuses) réparties sur plus de 300 placettes en France, nous avons 1) décrit et interprété les variations spatiales et interannuelles de déficit foliaire, en plus de 2) discuté de l’utilisation du déficit foliaire comme indicateur de l’état sanitaire des arbres à partir de l’analyse conjointe des variations interannuelles de déficit foliaire et de croissance radiale. L’analyse des variations géographiques du déficit foliaire a montré de multiples relations avec les facteurs édaphiques et climatiques, mais avec un pouvoir explicatif relativement modéré. L’analyse des variations interannuelles de déficit foliaire a permis de confirmer que les facteurs climatiques de l'année précédente contrôlent les variations interannuelles de déficit foliaire. Cependant, comparativement à la croissance radiale, le déficit foliaire présente une réponse au climat moins dynamique et peu cohérente entre arbres d’une même placette. L’analyse conjointe des deux signaux a montré l’existence d’un lien ténu entre la croissance et le déficit foliaire. Nous avons pu mettre en évidence une diminution de la croissance de l’arbre dans le cas de déficit foliaires importants lors d’années d’aléas climatiques extrêmes (sec ou froid). Cependant, l’introduction du déficit foliaire en tant que prédicteur de la croissance radiale n’a eu que peu ou pas d’effet significatif pour le hêtre et le sapin. Enfin, la mise en évidence de l’influence majeure de l’âge sur la notation du déficit foliaire empêche l’interprétation de déficit foliaire brut comme indicateur de la santé de l’arbre<br>For the past 30 years, annual visual assessments of crown condition, on the French part of the transnational monitoring network (ICP Forests, level 1), was essential for monitoring forest health. However, the use of crown condition as an indicator of tree health is regularly questioned for methodological reasons but also because of the lack of knowledge on the determinism of crown condition and its functional impact on the tree. In this context, and through the records of 9 tree species’ crown condition (deciduous and coniferous) spread over more than 300 plots in France, we have 1) described and interpreted the spatial and inter-annual variations of leaf loss, in addition to 2) discussing the use of crown condition as an indicator of tree health status based on the joint analysis of inter-annual variations of leaf loss and radial growth. The analysis of spatial variations in crown condition between plots showed multiple relationships with edaphic and climatic factors, but with relatively moderate explanatory power. The study of inter-annual variations in crown condition confirmed that the climatic factors of the previous year control crown condition of the current year. However, compared to radial growth, crown condition presents a less dynamic and inconsistent response to climate between trees in the same plot. The joint analysis of the two signals showed the existence of a weak link between growth and crown condition. We only observed a decrease in tree growth in the case of important leaf loss during years of extreme climatic hazards (dry or cold). However, the introduction of leaf loss as a predictor of radial growth had little or no significant effect for beech and fir. Finally, the evidence of the major influence of age on leaf loss precludes the interpretation of raw crown condition as an indicator of tree health
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49

Schmitt, Charlène Eva. "Caractérisation de polyacrylamide de hautes masses molaires par fractionnement couplage flux force couplée à la diffusion de la lumière." Thesis, Pau, 2015. http://www.theses.fr/2015PAUU3039.

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: L’une des méthodes qui consiste à optimiser la production d’hydrocarbure est basée sur l’injection d’eau, viscosifiée par addition de polymères de type polyacrylamides, afin d’améliorer l’extraction de pétrole (RAH). Or, les propriétés viscosifiantes des polymères dépendent de leurs masses molaires. L’enjeu de ce travail de thèse a donc été de mettre en place de nouvelles méthodes pour la détermination de larges distributions en masses molaires et de grande dispersité, caractéristiques propres aux échantillons d’intérêt industriel dans le domaine pétrolier. La stratégie d’analyse retenue repose sur la chromatographie d’exclusion stérique (CES) et le fractionnement par couplage flux force (A4F) couplés à la diffusion de lumière et à la réfractométrie. Des polymères modèles ont été synthétisés par un procédé de polymérisation par transfert de chaîne réversible par addition fragmentation (RAFT/MADIX). Cela a permis d’obtenir des polymères dans une gamme de masses molaires comprises entre 103 et 107 g/mol et avec une dispersité inférieure à 1,4. Via l’utilisation de ces polymères, les performances et limites des deux méthodes séparatives investies ont été évaluées. Les conditions opératoires en A4F ont été déterminées et cette méthode s’est avérée être adaptée à l’analyse de polymères industriels distribués sur 3 décades de masses molaires. Au delà de l’analyse dimensionnelle, le couplage avec l’A4F a également permis une analyse conformationnelle<br>One method for optimizing the production of hydrocarbon is based on the injection of water, viscosified by the addition of polymers such as polyacrylamides, in order to enhance the oil extraction (EOR). The viscosifying properties of polymers depend on their molecular masses. The aim of this thesis was therefore to develop new methods for determining wide molecular mass distributions and high dispersity, which are specific characteristics of samples of industrial interest in the oil sector. The analytical strategy used is based on size exclusion chromatography (SEC) and flow field flow fractionation (A4F), coupled to light scattering and refractometer. Model polymers were synthesized by a polymerization process by reversible addition fragmentation chain transfer (RAFT/MADIX). This allowed to obtain polymers in a range of molar masses between 103 and 107 g / mol and with a dispersity lower than 1.4. Through the use of these polymers, the capabilities and limitations of the two separation methods invested were evaluated. The A4F operating conditions were determined and this method has proved to be adapted to the analysis of industrial polymers distributed over 3 decades of molecular masses. Beyond the dimensional analysis, A4F-based coupling also allowed conformational analysis
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Гарбар, О. О. "Аналіз радіально-осьових коливань однодискового ротора". Master's thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/71069.

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Мета роботи – проведення аналізу радіально-осьових коливань однодискового ротору, оцінка радіальної статичної неврівноваженості, пульсацій тиску нагнітання і гармонійних змін осьової сили, діючої на ротор, оцінка критичних частот обертання ротора і амплітуди його змушених коливань. Мета дослідження – розглянути осьові коливання ротора, обумовлені його радіальними коливаннями. Тут же виводяться лінеаризовані рівняння спільних радіально-осьових коливань найпростішої одномасової моделі жорсткого ротора з автоматичним врівноважувальним пристроєм. Диск має статичну неврівноваженість. Досліджуються вимушені коливання системи під дією відцентрової сили неврівноваженої маси і урівноваженої осьової сили , діючої на ротор насоса і залежної від тиску нагнітання. У процесі роботи насоса пульсації тиску нагнітання відбуваються з частотою, кратною частоті обертання ротора, і викликають відповідні пульсації осьової сили.<br>Анализ радиально-осевых колебаний однодискового ротора.<br>Analysis of radial-axial oscillations of the one-disk rotor.
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