Academic literature on the topic 'Contact angle. eng'
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Journal articles on the topic "Contact angle. eng"
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Jaszak, Przemysław. "Optimized design of a semimetal gasket operating in flange-bolted joints." Open Engineering 11, no. 1 (November 19, 2020): 56–66. http://dx.doi.org/10.1515/eng-2021-0004.
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AbstractThe paper presents a new design of semimetal gasket, which has been subjected to the optimization process. The main objective function was to achieve the maximum elastic recovery of the gasket at imposed functional and strength limitations. The objective function was described indirectly in the form of the required minimum angle of the gasket’s unload curve inclination, which was a measure of the average value of the elastic modulus at unloading. Strength limitations resulted from not exceeding the ultimate stress of the materials, while functional limitations imposed the achievement of proper contact pressure that ensures a given level of tightness class. The characteristic dimensions describing the cross-section of the gasket’s core were described by five descriptive parameters. As a result of the interrelationship of these parameters, 210 construction models were created that were subjected to compression simulations. This problem was solved using the Finite Element Method. The variant of the gasket fulfilling the imposed limitations and the required minimum objective function was tested experimentally.
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GOMBA, J. M., and G. M. HOMSY. "Regimes of thermocapillary migration of droplets under partial wetting conditions." Journal of Fluid Mechanics 647 (March 18, 2010): 125–42. http://dx.doi.org/10.1017/s0022112010000078.
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We study the thermocapillary migration of two-dimensional droplets of partially wetting liquids on a non-uniform heated substrate. An equation for the thickness profile of the droplet is derived by employing lubrication approximations. The model includes the effect of a non-zero contact angle introduced through a disjoining–conjoining pressure term. Instead of assuming a fixed shape for the droplet, as in previous works, here we allow the droplet to change its profile with time. We identify and describe three different regimes of behaviour. For small contact angles, the droplet spreads into a long film profile with a capillary ridge near the leading edge, a behaviour that resembles the experiments on Marangoni films reported by Ludviksson & Lightfoot (Am. Inst. Chem. Eng. J., vol. 17, 1971, pp. 1166). For large contact angles, the droplet moves as a single entity, weakly distorted from its static shape. This regime is the usual one reported in experiments on thermocapillary migration of droplets. We also show some intriguing morphologies that appear in the transition between these two regimes. The occurrence of these three regimes and their dependence on various parameters is analysed.
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Hwang, T. W., C. J. Evans, and S. Malkin. "High Speed Grinding of Silicon Nitride With Electroplated Diamond Wheels, Part 2: Wheel Topography and Grinding Mechanisms." Journal of Manufacturing Science and Engineering 122, no. 1 (June 1, 1999): 42–50. http://dx.doi.org/10.1115/1.538909.
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This is the second in a series of two papers concerned with high speed grinding of silicon nitride with electroplated diamond wheels. In the first article (ASME J. Manuf. Sci. Eng., 122, pp. 32–41), it was shown that grinding of silicon nitride is accompanied by dulling of the abrasive grains and a significant increase in the grinding forces and power. High wheel speed caused more wheel wear, which was attributed to a longer accumulated sliding length between the abrasive grains and the workpiece. This second paper is concerned with the progressive change in wheel topography during grinding and how it affects the grinding process. A statistical model is developed to characterize the wheel topography during grinding in terms of active cutting grains and wear flat area. According to this model, continued grinding is accompanied by an increase in both the number of active grains and the wear flat area on the wheel surface as the wheel wears down. The measured increase in grinding forces and power was found to be proportional to the wear flat area, which implies a constant average contact pressure and friction coefficient between the wear flats and the workpiece. Increasing the wheel speed from 85 to 149 m/s significantly reduced the contact pressure, which may be attributed to a reduction of the interference angle, but had almost no effect on the attritious wear rate of the diamond abrasive. Therefore, more rapid wear of the diamond wheel at higher wheel speeds due to a longer sliding length may be offset by reduced contact pressures and lower grinding forces. [S1087-1357(00)00401-9]
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Tyowua, Andrew Terhemen, and Stephen Gbaoron Yiase. "Contact Angle Hysteresis – Advantages and Disadvantages: A Critical Review." Reviews of Adhesion and Adhesives 8, no. 1 (March 1, 2020): 47–67. http://dx.doi.org/10.7569/raa.2020.097302.
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The existence of contact angle hysteresis – the difference between the values of the advancing and receding contact angles – is evident in nature (e.g. sticking of rain drops to car windscreens and window panes) and many industrial processes (e.g. surface coating, spraying, and dyeing of fabrics). This phenomenon is often viewed as a nuisance, but it is advantageous in many processes including dip and spin coating, spraying, and painting. With the early theoretical framework of Thomas Young, Robert Wenzel, and A. B. D. Cassie and S. Baxter, describing the wettability of solid surfaces and by extension contact angle, contact angle hysteresis has been deeply investigated. We review here the various ways of measuring contact angle and, consequently, contact angle hysteresis as well as related theoretical models. The successes and limitations of these models are highlighted. We conclude with the advantages and disadvantages of contact angle hysteresis whose presence in many processes is often considered as a nuisance, especially when "coffee stain" forms from the evaporation of a volatile liquid drop containing nonvolatile components.
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Koshevoi, Veniamin L., Anton O. Belorus, Matyushkin В. Matyushkin, Ilya M. Pleshanov, Pavel V. Seredin, Sergey A. Ivkov, and Alexander S. Lenshin. "ВНЕДРЕНИЕ СЕРЕБРА В МАТРИЦУ ПОРИСТОГО КРЕМНИЯ МЕТОДОМ ЭЛЕКТРО-ТЕРМОДИФФУЗИИ." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 21, no. 3 (September 26, 2019): 390–98. http://dx.doi.org/10.17308/kcmf.2019.21/1158.
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В работе были проведены исследования возможности внедрения серебра в пористый кремний методом электро-термодиффузии и установлено влияние процедуры осаждения на адсорбционные свойства поверхности пористой матрицы. Композиты пористого кремния с внедренными частицами металла относятся к многофункциональным материалам и перспективны для применения в современной оптоэлектронике, сенсорике и персонализированной медицине.
ИСТОЧНИК ФИНАНСИРОВАНИЯИсследование выполнено при поддержке РФФИ в рамках научного проекта 19-32-50038мол_нр «Исследование морфологических, физико-химических и оптических свойств матриц наоснове por-Si в зависимости от методов их формирования и функционализации».
REFERENCES
Raúl J. Martín-palma, Patrick D. McAtee, Rehab Ramadan, Akhlesh Lakhtakia. Hybrid nanostructured porous silicon-silver layers for wideband optical absorption. Scientifi c Reports, 2019, v. 9(1), p. 7291. https://doi.org/10.1038/s41598-019-43712-7
Kleps I., Miu M., Danila M., Simion M., Ignat T., Bragaru A., Dumitru L., Teodosiu G. Silver/porous silicon (PS) nanocomposite layers for biomedical applications. Proc. of “2006 International Semiconductor Conference”, 27-29 Sep., 2006, no. 9211112. https://doi.org/10.1109/SMICND.2006.283935
Ensafi A. A., Rezaloo F., Rezaei B. Electrochemical sensor based on porous silicon/silver nanocomposite for the determination of hydrogen peroxide. Sensors and Actuators B, 2016, v. 231, pp. 239–244. https://doi.org/10.1016/j.snb.2016.03.018
Jinjie Yin, Xiang Qi, Liwen Yang, Guolin Hao, Jun Li, Jianxin Zhong A hydrogen peroxide electrochemical sensor based on silver nanoparticles decorated silicon nanowire arrays. Electrochimica Acta, 2011, v. 56(11), pp. 3884–3889. https://doi.org/10.1016/j.electacta. 2011.02.033
Spivak Yu. M., Bespalova K. A., Belorus A. O., Panevin A. A., Somov P. A., Grigor’eva N. Yu., Chistyakova L. V., Zhuravskiy S. G., Moshnikov V. A. Sposob polucheniya i primer lekarstvennoy funktsionalizatsii poverkhnosti nanochastits poristogo kremniya [A method of obtaining and an example of drug functionalization of the surface of porous silicon nanoparticles]. Biotekhnosfera [Biotechnosphere], 2017 (3), pp. 69–75. (in Russ.)
Pastukhov A. I., Belorus A. O., Bukina Ya. V., Spivak Yu. M., Moshnikov V. A. Infl uence of technology conditions on the surface energy of porous silicon using the method of contact angle. Proc. of “2017 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)”, 1–3 Feb., 2017, pp. 1183-1185. https://doi.org/10.1109/eiconrus.2017.7910770
Matyushkin L. B. Tekhnologiya i oborudovanie dlya polucheniya kolloidnykh kvantovykh tochek CsPbX3 (X = Cl, Br, I), CdSe/ZnS, plazmonnykh nanochastits Ag/SiO2 i gibridnykh struktur na ikh osnove [Technology and equipment for obtaining CsPbX3 colloidal quantum dots (X = Cl, Br, I), CdSe/ZnS, Ag/SiO2 plasmonic nanoparticles and hybrid structures based on them. Cand. Sci. (Eng.) diss. St. Petersburg, 2018, 138 p. URL: https://elibrary.ru/item.asp?id=35115356 (in Russ.)
Permiakov N. V., Matyushkin L. B., Belorus A. O., Koshevoi V. L. Investigation of a program-controlled process of impregnation of porous semiconductors with silver nanoparticles to create an electrical contact. Proc. of “IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus)”, 2018, pp. 539–543. https://doi.org/10.1109/EICon- Rus.2018.8317154
Travkin P. G., Vorontsova N. V., Vysotsky S. A., Lenshin A. S., Spivak Yu. M., Moshnikov V. A. Issledovanie zakonomernostey formirovaniya struktury poristogo kremniya pri mnogostadiynykh rezhimakh elektrokhimicheskogo travleniya [Study of regularities of porous silicon structure formation with multistage modes of electrochemical etching]. Izvestiya SPBGETU LETI, 2011(4). pp. 3–9. (in Russ.)
Belorus A. O., Komlev A. A. Certifi cate of state registration of computer programs No. 2014613394. Measurement of contact angle (MofCA) 26 March 2014. (in Russ.)
Van Hoonacker A., Englebienne P. Revisiting silver nanoparticle chemical synthesis and stability by optical spectroscopy. Current Nanoscience, 2006, v. 2(4), pp. 359–371. https://doi.org/10.2174/157341306778699310
Girel K. V., Bondarenko A. V. Formirovanie nanostruktur serebra metodom immersionnogo osazhdeniya [Formation of silver nanostructures by immersion deposition method onto porous silicon and study of their optical properties]. Doklady BGUIR, 2014, v. 86(8), pp. 5–10. (in Russ.)
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Wang, Lei, Lei Chen, and Zhanxiong Li. "End-Blocked Silanization of Side-Chain Fluoroalkyl Oligoether and its Surface Properties." Australian Journal of Chemistry 71, no. 11 (2018): 855. http://dx.doi.org/10.1071/ch18126.
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In this study, three novel side-chain fluoroalkyl oligoethers with different molecular weights were synthesised via a ring-opening reaction of 2,2,3,3,4,4,5,5,5-nonafluoropentyloxirane. The fluorooligoethers were then silanized and characterised by FT-IR,1H, and 19F NMR spectroscopies. These silanlized fluorooligoethers were used to fabricate hydrophobic coatings on silicon substrates, which were pre-treated with O2 plasma, by the method of liquid phase deposition. The chemical compositions and structures of the film surfaces were analysed by X-ray photoelectron spectroscopy and the results showed that silanized fluorooligoethers formed self-assembled films on the silicon wafer. The surface wettability of the coatings was measured by water contact angles. It is noted that the annealing process can improve the hydrophobicity with the highest water contact angle being 115.2 ± 1° and hexadecane contact angle being 67.2 ± 1°. The surface morphologies and roughness of the self-assembled films were measured by atomic force microscopy (AFM), as a result, the surface was found to be rougher with the increment of the molecular weight of the fluorooligoethers.
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Ponomarev, B. B., and S. H. Nguyen. "Evaluation of Surface Roughness in Five-Axis Ball-End Milling." Proceedings of Higher Educational Institutions. Маchine Building, no. 05 (722) (May 2020): 21–31. http://dx.doi.org/10.18698/0536-1044-2020-5-21-31.
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Unlike three-axis machining, five-axis machining allows the end tool or workpiece to be oriented at any angle relative to the machine axis OZ. It can be achieved by changing the values of the tool tilt angle and lead angle relative to the surface normal in the contact zone of the tool surface and the workpiece, taking into account the direction of the table feed. The article presents experimental results of analyzing the influences of tool orientation on transverse roughness during ball end milling using 2-flute and 4-flute 8 mm diameter mills. The analysis the arithmetic mean deviation of the assessed profile at various values of tool tilt angle and lead angle showed that the position of the tool point with a zero cutting speed significantly affects the surface quality. The results of the evaluation of the tool orientation influence on the surface roughness enable the selection of optimal tool orientation angles when developing control programs for end milling of free-form surfaces on five-axis CNC milling machines.
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Cortes, Nelson, James Onate, João Abrantes, Linda Gagen, Elizabeth Dowling, and Bonnie Van Lunen. "Effects of Gender and Foot-Landing Techniques on Lower Extremity Kinematics during Drop-Jump Landings." Journal of Applied Biomechanics 23, no. 4 (November 2007): 289–99. http://dx.doi.org/10.1123/jab.23.4.289.
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The purpose of this study was to assess kinematic lower extremity motion patterns (hip flexion, knee flexion, knee valgus, and ankle dorsiflexion) during various foot-landing techniques (self-preferred, forefoot, and rear foot) between genders. 3-D kinematics were collected on 50 (25 male and 25 female) college-age recreational athletes selected from a sample of convenience. Separate repeated-measures ANOVAs were used to analyze each variable at three time instants (initial contact, peak vertical ground reaction force, and maximum knee flexion angle). There were no significant differences found between genders at the three instants for each variable. At initial contact, the forefoot technique (35.79° ± 11.78°) resulted in significantly (p= .001) less hip flexion than did the self-preferred (41.25° ± 12.89°) and rear foot (43.15° ± 11.77°) techniques. At peak vertical ground reaction force, the rear foot technique (26.77° ± 9.49°) presented significantly lower (p= .001) knee flexion angles as compared with forefoot (58.77° ± 20.00°) and self-preferred (54.21° ± 23.78°) techniques. A significant difference for knee valgus angles (p= .001) was also found between landing techniques at peak vertical ground reaction force. The self-preferred (4.12° ± 7.51°) and forefoot (4.97° ± 7.90°) techniques presented greater knee varus angles as compared with the rear foot technique (0.08° ± 6.52°). The rear foot technique created more ankle dorsiflexion and less knee flexion than did the other techniques. The lack of gender differences can mean that lower extremity injuries (e.g., ACL tears) may not be related solely to gender but may instead be associated with the landing technique used and, consequently, the way each individual absorbs jump-landing energy.
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Cai, Shaobiao, and Bharat Bhushan. "Meniscus and viscous forces during separation of hydrophilic and hydrophobic smooth/rough surfaces with symmetric and asymmetric contact angles." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 366, no. 1870 (January 11, 2008): 1627–47. http://dx.doi.org/10.1098/rsta.2007.2176.
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Adhesive or repulsive forces contributed by both meniscus and viscous forces can be significant and become one of the main reliability issues when the contacting surfaces are ultra smooth, and the normal load is small, as is common for micro/nano devices. In this study, both meniscus and viscous forces during separation for smooth and rough hydrophilic and hydrophobic surfaces are studied. The effects of separation distance, initial meniscus height, separation time, contact angle and roughness are presented. Meniscus force decreases with an increase of separation distance, whereas the viscous force has an opposite trend. Both forces decrease with an increase of initial meniscus height. An increase of separation time, initial meniscus height or a decrease of contact angle leads to an increase of critical meniscus area at which both forces are equivalent. An increase in contact angle leads to a decrease of attractive meniscus force but an increase of repulsive meniscus force (attractive or repulsive dependent on hydrophilic or hydrophobic surface, respectively). Contact angle has a limited effect on the viscous force. For asymmetric contact angles, the magnitude of the meniscus force and the critical meniscus area are in between the values for the two angles. An increase in the number of surface asperities (roughness) leads to an increase of meniscus force; however, its effect on viscous force is trivial. A slightly attractive force is observed for the hydrophobic surface during the end stage of separation though the magnitude is small. The study provides a fundamental understanding of the physics of the separation process and it can be useful for control of the forces in nanotechnology applications.
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Ferreira, Rodrigo, Gabriel Lopes de Castro Martinelli, Alessandro Roger Rodrigues, and Reginaldo Teixeira Coelho. "Tool Feed and Burr Size Influence on Wettability of Ti6Al4V Micro End-Milled." International Journal of Engineering Materials and Manufacture 6, no. 3 (July 15, 2021): 114–23. http://dx.doi.org/10.26776/ijemm.06.03.2021.02.
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Surface texturing, using micro-milling, has promising applications in the industry of medical implants, since it can assist cell adhesion and thus improve osseointegration. Ti6Al4V alloy is used as implant material due to its excellent biocompatibility and high mechanical strength. However, those mechanical properties reduce machinability creating some challenges for micro-milling. The way to initially assess cell adhesion is using surface wettability, usually conducted with water. At the present work, micro-channels were machined in Ti6Al4V by micro end-milling with 500 µm width per 50 µm depth with 1000 µm distant from each other. The effect of feed per tooth (fz) on wettability was analysed and some interesting relations with burrs formed on channel walls were obtained. Values of feed per tooth were 3, 6, 12 and 15 µm. Wettability results showed that slotted surface is more hydrophilic on channel direction, with contact angles around 30° to 43°. In contrast, on the perpendicular direction the surface tends to be hydrophobic with contact angles between 75° and 146°. In addition, contact angle increases (hydrophobic tendency) as feed per tooth increases (along with roughness), even on channel direction. The presence of burrs also tends to disturb wettability results. Therefore, surface wettability depends on channel direction, burr size and tool feed per tooth, as well.
Dissertations / Theses on the topic "Contact angle. eng"
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Iost, Cristina Abi Rached 1982. "Efeito de adjuvantes nas propriedades físico-químicas da água e na redução de deriva em pulverizações sobre diferentes espécies de plantas daninhas /." Botucatu : [s.d. ], 2008. http://hdl.handle.net/11449/97153.
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Orientador: Carlos Gilberto RaetanoBanca: Ulisses Rocha Antuniassi
Banca: Cristina Gonçalves de Mendonça
Resumo: Este trabalho teve como objetivo avaliar o efeito de adjuvantes sobre algumas propriedades de soluções aquosas, como tamanho de gotas, tensão superficial dinâmica e ângulo de contato das gotas em diferentes superfícies, natural e artificial, bem como avaliar o efeito desses produtos sobre a deposição e a deriva utilizando como alvo três espécies de plantas daninhas (Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea). Seis formulações de adjuvantes (Antideriva®, Uno®, Pronto 3®, Li-700®, Supersil® e Silwet L-77®) foram avaliadas em soluções aquosas contendo a dose recomendada do produto comercial e o dobro dela. As avaliações de tamanho de gotas foram feitas com três diferentes pontas de pulverização (AXI 110 015, 110 02 e 110 03) por um equipamento a laser (Mastersizer, Malvern) na pressão de trabalho de 414 kPa. Os ângulos de contato formados pelas gotas em duas superfícies, uma hidrofílica (vidro) e outra hidrofóbica (óxido de alumínio), foram obtidos por análise de imagens capturadas por uma câmera digital. As avaliações de deposição e deriva das soluções aquosas associadas ou não aos adjuvantes e contendo o traçador azul brilhante (0,15% v/v), foram feitas sobre diferentes espécies vegetais, e com o auxílio de coletores laterais (placas de Petri). A quantificação do traçador foi por feita espectrofotometria. A tensão superficial dinâmica e o ângulo de contato formado sobre as superfícies adaxiais das folhas foram medidos por um tensiômetro. Em relação ao tamanho de gotas, o adjuvante Antideriva, com dobro da dose recomendada, foi o que apresentou os menores valores percentuais de volume de gotas com diâmetro menor que 100 µm e os maiores DMV, para todas as pontas em teste. As soluções que proporcionaram as maiores ...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The aim of this work is to evaluate the effect of adjuvants on droplet size, dynamic surface tension and contact angle formed by the water drops in different surfaces, as well as evaluating the adjuvants effect on the deposit and the spray drift using three species of plants (Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea). We studied six adjuvants formulations (Antideriva, Uno, Pronto 3, Li- 700, Supersil and Silwet L-77) in water solution using the dosage recommended by the manufacturer and twice that dose. The droplet size of three different nozzles (AXI 110 015, 110 02 and 110 03), for a constant pressure of 414 kPa, were evaluated by a laser system. The contact angles of the drops in two surfaces (hydrophilic and hydrophobic) were obtained by the analysis of images captured by a digital camera. The evaluation of deposition and spray drift deposition of the solutions containing brilliant-blue dye (0.15 % v/v) were carried out in different plant species. The solutions were collected laterally using Petri dishes, and the brilliant-blue dye content quantified by absorption spectroscopy. The dynamic surface tension and the angle formed on the surfaces of the leaves were measured by a tensiometer. Regarding the droplet size, for all the nozzles tested the adjuvant Antideriva with twice the recommended dose presented the lowest percentage of spray volume in droplets with diameters smaller than 100µm, and highest VMD. The solutions that provided the highest reductions in the dynamic surface tension and the smallest contact angle were the ones with the adjuvants Silwet L-77 and Supersil for both appraised doses. The largest deposit average for I. grandifolia was obtained by using Uno with double of the dose; for B. ...(Complete abstract click electronic access below)
Mestre
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Caldari, Valentina. "The end of the Anglo-Spanish match in global context, 1617-1624." Thesis, University of Kent, 2015. https://kar.kent.ac.uk/53723/.
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A marriage between the English Prince and the Spanish Infanta was deemed desirable following the signing of the Anglo-Spanish peace treaty in London in 1604. After several years of tortuous negotiations, the match failed in 1624 and England declared war on Spain the following year. This thesis addresses the end of the Anglo-Spanish Match negotiations in the period 1617-1624 by placing reasons for its failure in the global context of European diplomacy and dynastic politics in the early seventeenth century. Traditional historiography has considered the failure of the marriage diplomacy as the inevitable consequence of religious differences and cultural misunderstandings between England and Spain. Consequently, scholars have only looked within Europe when investigating the end of the union. My research, however, depicts a more composite picture not only by expanding the geographical boundaries of the investigation but also by demonstrating the extent to which new imperial rivalries played a much greater role in the marriage diplomacy than has previously been recognised. In the first chapter, I discuss the notion of reason of state in the relationship between England and Spain at the beginning of the seventeenth century and I investigate the way in which the choice politically and/or economically most favourable was often taken regardless of religious considerations and increasingly in response to extra-European concerns. The body of the thesis is then dedicated to a few episodes when the imperial rivalry between England and the Iberian Peninsula influenced the end of the negotiations. In the second chapter, I look at Walter Raleigh’s second expedition to Guyana and the actions of the Spanish ambassador in London, Count of Gondomar, who asked that Raleigh should receive an exemplary punishment in order to maintain the marriage agreement after the English explorer had attacked Spanish settlements. In the following chapter, I move towards the East and analyse the taking of the Portuguese port of Hormuz in the Persian Gulf by the English East India Company in 1622. In doing so, I outline the complex dynamics underlying the union of the Iberian crowns (1580-1640) as well as the specific repercussions of this episode on the Infanta’s dowry to be given by Spain to England. The fourth chapter introduces a further key player in both European diplomacy and the imperial rivalry between Spain and England, which is to say the Dutch. By looking at the ‘massacre’ at Amboyna in 1623, I prove that the rivalry with the Dutch in the Spice Islands, and especially the executions at Amboyna, initially pushed King James to pursue the marriage alliance with the Spanish Habsburgs with even greater commitment. In the last chapter, I look back at Europe to discuss how the two composite monarchies reacted to the arrival at their respective courts of the news of recent episodes of conflict in the West and East Indies. This concluding chapter argues that the awareness in Madrid and London of what had happened in the Indies put additional burdens onto the already deteriorating marriage negotiations and fundamentally contributed to their failure. Thus, the thesis sheds light on a well-known episode of Anglo-Spanish relations by observing it through a new lens. As a result, I improve our traditional understanding of the end of Anglo-Spanish Match as well as of global connectedness in the early seventeenth century.
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Lomax, Deborah. "Electrowetting and electrodeposition on graphitic surfaces." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/electrowetting-and-electrodeposition-on-graphitic-surfaces(0ecee720-fb95-48cb-bfb2-75e7adc305f3).html.
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Graphite and graphene electrodes are used to study two electrochemical processes: the decoration of these electrodes with Au metallic nanoparticles through the use of electrodeposition, and electrowetting, the potential-dependent change in hydrophobicity of a surface. Electrodeposition provides a useful route to electrode functionalisation, in particular to combine the enhanced properties of metallic nanoparticles with the advantageous features of carbon materials. A combination of cyclic voltammetry, chronoamperometry, and both ex situ and in situ atomic force microscopy are used to deduce the mechanism of Au electrodeposition on graphite and graphene. Notably, the mechanism of Au nanoparticle formation cannot be deduced from simple voltammetry alone, and the spontaneous formation of Au within the timescale of the electrodeposition experiment is confirmed. Electrowetting is a uniquely responsive method to manipulate the wetting properties of an electrode. However, a dielectric coating is commonly required to protect the surface from electrolysis, which in turn further increases the potentials needed to perform electrowetting. In contrast to this, here it is shown that bare graphite and graphene electrodes support electrowetting without the disadvantages of a dielectric coating, allowing an unprecedented combination of performance and efficiency. Furthermore, the ideal behaviour this system demonstrates is implemented as a platform to study electrowetting itself. The influence of electrolyte composition, surface defects and electrode-blocking dielectric-like films are investigated to determine the factors that impede electrowetting, a key step to understanding the phenomenon that is normally hindered by the use of the dielectric.
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Almoughni, Hend Mohammed Aa. "Capillary flow of liquid water through plain knitted fabrics." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/capillary-flow-of-liquid-water-through-plain-knitted-fabrics(4cd71022-212f-4536-8a5f-532fcd0883d0).html.
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In extreme weather conditions and activity levels of human subjects evaporation of sweat is critical for maintaining the sensorial and thermal comfort. Fabrics, from which clothes worn next to the skin are made, play an important role in facilitating the transfer of body liquid perspiration away from the skin to the environment through the mechanisms of capillary flow and evaporation. This work is a theoretical and experimental investigation of water flow characteristics of plain knitted fabrics with relevance to their structure geometry and constituent fibre chemistry. Plain knitted fabrics were produced by systematically varying different production parameters including fibre type, fibre orientation, yarn folding, yarn twist, yarn linear density, and blend ratio. Cotton and polyester fibres were used. Some commercial fabrics were included in the study. The gravimetric absorbency test system (GATS) was adapted for testing the water areal flow and uptake rates through the fabrics. Yarns taken from the produced fabrics were also tested for horizontal linear flow of liquid water. A theoretical model to predict the capillary flow of liquid water through yarns was proposed. The model is based on the representation of the inter-fibre pores in terms of the hydraulic radius theory. It is established that the plain knitted fabric configuration as interlocking of loops plays an important role in facilitating the capillary flow of liquid water through the fabric. The yarn contact at the crossover points of the knitted loop enables a connected path for liquid flow which increases at higher contact pressure at the crossover points. If the contact pressure increases beyond a certain limit it starts to negatively affect the flow because the higher pressure reduces yarn porosity. When the number of yarns in contact with the liquid source per unit area of the fabric plane increases the capillary flow increases. Fabric compactness, which is controlled by yarn diameter and stitch length, is an important fabric parameter that determines these effects the fabric configuration have on the capillary flow. The experiments and the micro-structural analysis revealed that inter-fibre pores within the plain knitted fabric transfer the capillary driven liquid water through the structure at a faster rate. These pores hold the higher percentage of the fabric total air volume. It was also established that both fibre chemical nature and yarn fine structure geometry have critical effects on the apparent contact angle which is a critical factor controling capillary flow of liquid water. The smooth yarn surface made of filament polyester fibre gave a low apparent contact angle in contrast with the constituent filament which showed a high real contact angle. On the contrary, due to the more disorderly fibre arrangement on the yarn surface, yarns made of the staple polyester fibre showed a similar high contact angle to the constituent fibre. The experimental results of capillary flow of liquid water through yarns showed a strong correlation with the estimated results based on the theoretical model derived from the Kozeny-Carman equation. The model provides theoretical basis for understanding the effects of the geometric and material parameters on the capillary flow through the yarn. The model predicts that as the total fibre perimeter within the yarn cross section increases, or yarn porosity decreases, the velocity decreases, however, the eventual distance the water travels through the yarn increases.
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Bowens, Andrea Demetrius. "Synthesis and Characterization of Poly(siloxane imide) Block Copolymers and End-Functional Polyimides for Interphase Applications." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29985.
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End-functional poly(ether amic acid)s and poly(siloxane imide) multiblock copolymers, comprised of 2,2'-Bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) / meta-phenylene diamine (MPDA) and hexafluoroisopropylidene-2-bis(phthalic acid anhydride) (6FDA) / meta-phenylene diamine (MPDA) polyimide segments, have been prepared and characterized to explore possibilities for controlling interface properties. Incorporation of polydimethylsiloxane (PDMS) components into polyimide backbone structures can yield advantageous properties such as low energy surfaces and low stress interfaces.
End-functional BPDA/MPDA poly(amic acid) salts and poly(siloxane amic acid) salts were prepared in methanolic or aqueous tripropylamine solutions. The polymeric salts formed stable water solutions (or dispersions) and imidized in less than 10 minutes at 260°C. The water solubility and rapid imidization times are ideal for on-line processing. Thus, these materials can be used as sizing and interface toughening agents for fiber reinforced composite manufacturing. Epoxy-polyimide networks prepared from the amine functionalized polyimide with DER 331 epoxy resin and diamino diphenylsulfone showed microphase separation (100-300 nm inclusions) by transmission electron microscopy. Slight toughening of the cured epoxy with 9 weight % imide was observed with the imide as the included phase. Epoxy bilayer films of polyimide (amine end-functional and commercial Ultem⠢) and poly(siloxane imide) multiblock copolymers were prepared to evaluate the polymer-matrix interphase region. Atomic force microscopy (AFM) analysis of the bilayer films showed diffusion at the interphase for the bilayers prepared with the polyimides and the BPADA/MPDA block copolymers containing polyimide continuous phases.
Poly(siloxane imide) multiblock copolymers comprised of 6FDA/MPDA polyimide structures are ideal candidates for controlling interfacial properties between silicon substrates layered with thin films for microelectronic applications. These high Tg materials offer an approach for obtaining reduced moisture absorption and low stress interfaces. Evaluation of the refractive indices of the block copolymer films showed a decrease with increasing siloxane content thus suggesting the possibility of lower dielectric constants. The polymer-metal interfacial properties were investigated for films cast on titanium and tantalum substrates. The results suggested a correlation between the surface hydroxyl concentration of the metal oxide layer with the interfacial properties of the cast poly(siloxane imide) block copolymer films. The surface hydroxyls were thought to hydrogen bond with the PDMS component of the block copolymer. Since the titanium substrate has a higher surface hydroxyl concentration than the tantalum, higher silicon concentrations were observed.
The melt imidized end-functional polyimides and poly(siloxane imide) block copolymers produced thermally stable materials with 5% weight loss temperatures well above 400°C. However, the block copolymers showed slightly lower 5% weight loss temperatures as a function of siloxane content with a significant increase in char formation. Correlation of the upper glass transition temperatures with the imide segment length was consistent with findings noted for other phase separated randomly segmented block copolymers.
Incorporating PDMS into the polyimide backbone structure has an effect on the bulk and surface properties. The bulk properties of the poly(siloxane imide) block copolymers were characterized using TEM. The morphologies were consistent with classical block copolymers. Surface properties of the block copolymer films as a function of PDMS content were investigated using angular dependent X-ray photoelectron spectroscopy at take-off angles of 15, 30, and 45°. Surface enrichment of PDMS content over that of the bulk was observed at all three sampling depths. Further evidence of this siloxane enrichment in the surface was demonstrated with water contact angle analyses. With as little as 5 weight % PDMS (Ph. D.
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Alhargan, Haya Saleh. "Anglo-Saudi cultural relations : challenges and opportunities in the context of bilateral ties, 1950-2010." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/anglosaudi-cultural-relations(d5846215-2066-4c9c-ae3b-278fb7a628f7).html.
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This study investigates Anglo-Saudi cultural relations from 1950 to 2010, with the aim of greater understanding the nature of those relations, analysing the factors affecting them and examining their role in enhancing cultural relations between the two countries. Furthermore, the thesis is grounded within the area of public diplomacy, using cultural exchange as a means of developing ties between the UK and Saudi Arabia, and evaluating the power of Saudi-British cultural diplomacy to improve bilateral relations. This thesis has been undertaken using an analysis methodology in order to examine the factors and events effecting Anglo-Saudi cultural relations by providing a study of political, economic, security and educational factors and their impact on such relations. It questions how and why certain events occurred, how these impacted on cultural ties, and then examines the ensuing consequences. The research is made up of seven chapters. The first chapter provides an explanation of the conceptual and theoretical development of culture, cultural relations and cultural diplomacy. In the second chapter the thesis deals with the historical background of Anglo-Saudi relations and its current development, and then examines the factors that have impacted on Saudi-British bilateral relations, specifically the Buraimi and the Suez crises during the 1950s and 1960s in chapter 3, booming oil prices in the 1970s in chapter 4, the higher education links between Saudi Arabia and Britain during the 1980s and 1990s in chapter 5, the relationship in the light of the events of 11 September 2001 in chapter 6, and finally the growth of educational co-operation and the role of the British Council in the Kingdom of Saudi Arabia (KSA) and the Saudi Cultural Bureau in London in chapter 7. In its examination of cultural, political and educational factors, the study has drawn on primary data from various archives in both Britain and Saudi Arabia, in addition to reports from the British Council, the Saudi Embassy, the Cultural Bureau in London and other secondary sources.
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Read, Michael Leonard. "The impact of material surface characteristics on the clinical wetting properties of silicone hydrogel contact lenses." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-impact-of-material-surface-characteristics-on-the-wetting-properties-of-silicone-hydrogel-contact-lenses(f9052c88-3fe8-4467-8cda-7feb5b63c066).html.
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This PhD project investigated the ramifications of air-cured and nitrogen-cured manufacturing processes during silicone hydrogel contact lens manufacture in terms of lens surface characterisation and clinical performance. A one-hour contralateral clinical study was conducted for ten subjects to compare the clinical performance of the two study lenses. The main clinical findings were reduced levels of subjective performance, reduced surface wettability and increased deposition. Contact angle analysis showed the air-cured lenses had consistently higher advancing and receding contact angle measurements, in comparison with the nitrogen-cured lens. Chemical analysis of the study lens surfaces in the dehydrated state, by x-ray photoelectron spectroscopy (XPS) and time-of-flight mass spectrometry (ToF-SIMS), showed no difference due to surface segregation of the silicone components. Analysis of frozen lenses limited surface segregation and showed a higher concentration of silicone polymer components and lower concentration of hydrophilic polymer components at the surface of the air-cured lens, in comparison with the nitrogen-cured lens. Scanning electron microscope (SEM) imaging showed the nitrogen-cured lens to have a surface typical of a hydrogel material, whereas the air-cured lens had regions of apparent phase separation. In addition, atomic force microscopy (AFM) showed the air-cured lens to have a rougher surface associated with greater adherence of contaminants (often observed in materials with reduced polymer cross-linking). In conclusion, clinical assessment of the study lenses confirmed the inferior performance of the air-cured lens. Surface analysis suggested that the non-wetting regions on the air-cured lenses were associated with elevated level of silicone components, reduced polymer cross-linking and polymer phase separation.
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Madaan, Nitesh. "Synthesis and Characterization of Complex Molecular Assemblies on Surfaces." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5748.
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The research presented in this dissertation is focused on the construction of complex molecular structures on planar gold and silicon dioxide surfaces using a variety of surface modification techniques, along with thorough surface characterization at each modification step. The dissertation is structured into six separate chapters. In Chapter 1, an introduction to the importance and implications of molecular level surface modification, commonly employed surface modification methods, and available surface characterization techniques is presented. Chapter 2 shows applications of novel methodologies for the functionalization of gold surfaces using alkane dithiol self-assembled monolayers and thiol-ene click chemistry. The resulting functionalized gold substrates demonstrate higher chemical stability than alkanethiol self-assembled monolayers alone and allow spatially controlled functionalization of gold surfaces with light. In Chapter 3, work on tunable hydrophobic surfaces is presented. These surfaces are prepared using a combination of organosilane chemistry, layer-by-layer polyelectrolyte deposition, and thiol-ene chemistry. These hydrophobic surfaces demonstrate high mechanical and chemical stability, even at low pH (1.68). The pinning of water droplets could be tuned on them by the extent of their thermal treatment. Comprehensive surface characterization using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), spectroscopic ellipsometry, atomic force microscopy, and water contact angles was carried out on the molecular assemblies prepared on gold and silicon dioxide surfaces. Chapters 4 and 5 are focused on the application, data interpretation, and enhancement in sensitivity of different surface characterization methods. In Chapter 4, XPS, ToF-SIMS, and principal components analysis are used to probe a real world corrosion-type problem. This systemic study showed the destruction of a protective coating composed of a nitrilotris(methylene)triphosphonic acid by a low-intensity fluorine plasma. In Chapter 5, enhancement in ToF-SIMS signals is shown via bismuth metal deposition. These surfaces are also probed by spectroscopic ellipsometry using the interference enhancement method. Finally, Chapter 6 concludes this dissertation by describing possible future work.
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Li, Qi. "Acoustic noise emitted from overhead line conductors." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/acoustic-noise-emitted-from-overhead-line-conductors(90a5c23c-a7fc-4230-bbab-16b8737b2af2).html.
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The developments of new types of conductors and increase of voltage level have driven the need to carry out research on evaluating overhead line acoustic noise. The surface potential gradient of a conductor is a critical design parameter for planning overhead lines, as it determines the level of corona loss (CL), radio interference (RI), and audible noise (AN). The majority of existing models for surface gradient calculation are based on analytical methods which restrict their application in simulating complex surface geometries. This thesis proposes a novel method which utilizes both analytical and numerical procedures to predict the surface gradient. Stranding shape, proximity of tower, protrusions and bundle arrangements are considered within this model. One of UK National Grid's transmission line configurations has been selected as an example to compare the results for different methods. The different stranding shapes are a key variable in determining dry surface fields. The dynamic behaviour of water droplets subject to AC electric fields is investigated by experiment and finite element modelling. The motion of a water droplet is considered on the surface of a metallic sphere. To understand the consequences of vibration, the FEA model is introduced to study the dynamics of a single droplet in terms of phase shift between vibration and exciting voltage. Moreover, the evolution of electric field within the whole cycle of vibration is investigated. The profile of the electric field and the characteristics of mechanical vibration are evaluated. Surprisingly the phase shift between these characteristics results in the maximum field occurring when the droplet is in a flattened profile rather than when it is ‘pointed’.Research work on audible noise emitted from overhead line conductors is reviewed, and a unique experimental set up employing a semi-anechoic chamber and corona cage is described. Acoustically, this facility isolates undesirable background noise and provides a free-field test space inside the anechoic chamber. Electrically, the corona cage simulates a 3 m section of 400 kV overhead line conductors by achieving the equivalent surface gradient. UV imaging, acoustic measurements and a partial discharge detection system are employed as instrumentation. The acoustic and electrical performance is demonstrated through a series of experiments. Results are discussed, and the mechanisms for acoustic noise are considered. A strategy for evaluating the noise emission level for overhead line conductors is developed. Comments are made on predicting acoustic noise from overhead lines. The technical achievements of this thesis are summarized in three aspects. First of all, an FEA model is developed to calculate the surface electric field for overhead line conductors and this has been demonstrated as an efficient tool for power utilities in computing surface electric field especially for dry condition. The second achievement is the droplet vibration study which describes the droplets' behaviour under rain conditions, such as the phase shift between the voltage and the vibration magnitude, the ejection phenomena and the electric field enhancement due to the shape change of droplets. The third contribution is the development of a standardized procedure in assessing noise emission level and the characteristics of noise emissions for various types of existing conductors in National Grid.
Books on the topic "Contact angle. eng"
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Rodrigues da Silva, Renato. The Anglo-Saxon Elite. NL Amsterdam: Amsterdam University Press, 2021. http://dx.doi.org/10.5117/9789463721134.
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In all of the literature on Anglo-Saxon England, rarely has the question of social class been confronted head-on. This study draws upon recent research into topics such as religious practice, emotions, daily life, and intellectual culture to investigate how the aristocracy of Northumbria maintained social dominance over wider society. Moreover, this monograph suggests that the crisis that brought an end to Northumbria as an independent kingdom was the product of the social contradictions produced by the ruling class as social domination developed over time. The analysis is divided into three broad parts – production, circulation, and consumption – both as a nod to Marxist historiography and also to signal a commitment to a methodology that situates the subject within a global context.
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Pang, Changhyun, Chanseok Lee, Hoon Eui Jeong, and Kahp-Yang Suh. Skin and dry adhesion. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0022.
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Close observation of various attachment systems in animal skins has revealed various exquisite multi-scale architectures for essential functions such as locomotion, crawling, mating, and protection from predators. Some of these adhesion systems of geckos and beetles have unique structural features (e.g. high-aspect ratio, tilted angle, and hierarchical nanostructure), resulting in mechanical interlocking mediated by van der Waals forces or liquid secretion (capillary force). In this chapter, we present an overview of recent advances in bio-inspired, artificial dry adhesives, and biomimetics in the context of nanofabrication and material properties. In addition, relevant bio-inspired structural materials, devices (clean transportation device, interlocker, biomedical skin patch, and flexible strain-gauge sensor) and microrobots are briefly introduced, which would shed light on future smart, directional, and reversible adhesion systems.
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Lobban, Michael. The Law of Obligations. Edited by Heikki Pihlajamäki, Markus D. Dubber, and Mark Godfrey. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780198785521.013.45.
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The Anglo-American law of obligations was profoundly reshaped in the two centuries after 1800, driven by social and economic changes, and changes in legal institutions and doctrines. In contract law, nineteenth-century jurists increasingly sought to put the rules of law into a coherent rational framework (inspired by continental models resting on will theory), though they soon found that this theory could not explain many contractual doctrines. In tort law, jurists were also divided over whether unifying principles underlying tort could be uncovered, with formalist efforts to find such principles being challenged by Realists who argued that tort was in effect ‘public law in disguise’. The quest for underlying principles was also pursued by scholars of unjust enrichment, first in the United States and subsequently in England; though as in the other areas of obligations, by the end of the twentieth century, there was no consensus on whether this was possible.
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Brink, David O., Susan Sauvé Meyer, and Shields Christopher, eds. Introduction. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198817277.003.0001.
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Through their writing, their teaching, their mentoring, and their broader scholarly output, Gail Fine and Terry Irwin have reshaped the character of ancient philosophy as an academic discipline. Their contributions to the discipline do not, however, end there. On the contrary, their wide-ranging achievements extend into all periods of the history of philosophy and indeed into several areas more systematic than historical. Or perhaps one should say, rather, that their work defies any ready classification as being either historical or systematic, because whatever its primary focus on a given occasion, what they write cannot be pigeonholed as either exclusively scholarly or thematic; for they practice an unremittingly philosophical form of history of philosophy, or, judged from another angle, a historically enriched form of systematic philosophy. That is, as they pursue it, philosophy engages the discipline’s history in a manner animated by its current and perennial concerns, but it does so while remaining fully sensitive to the original context of its production. Their work combines the highest level of scholarly rigor and rich philosophical insight. Animated by a purely philosophical spirit, it is never narrowly antiquarian in orientation. Although alert to matters of text and transmission reflecting painstaking philological care and exceptionally broad scholarly erudition, their work never loses sight of a simple question: should we too believe this?...
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Stafford, Pauline. After Alfred. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198859642.001.0001.
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This book traces the development of a group of anonymous, vernacular, annalistic chronicles—‘the Anglo-Saxon chronicles’—from their genesis at the court of King Alfred to their end at the Fenland monastery of Peterborough. It reconsiders them in the light of wider European scholarship on the politics of history-writing. It covers all surviving manuscript chronicles, with detailed attention being paid to palaeography, layout, and content, and identifies key lost texts. It is concerned with production, scribe-authors, patrons, and audiences. The centuries these chronicles cover were critical to the making of England and saw its conquest by Scandinavians and Normans. They have long been part of the English national story. The book considers the impact of this on their study and editing. It stresses their multiplicity, whilst identifying a tradition of writing vernacular history. It sees that tradition as an expression of the ideology of a southern elite engaged in the conquest and assimilation of old kingdoms north of the Thames, Trent, and Humber. The book connects many chronicles to bishops and especially to archbishops of York and Canterbury. Vernacular chronicling is seen, not as propaganda, but as engaged history-writing closely connected to the court, whose networks and personnel were central to the production of chronicles and their continuation. The disappearance of the English-speaking elite after the Norman Conquest had profound impacts on them, repositioning their authors in relation to the court and royal power, and ultimately resulting in the end of the tradition of vernacular chronicling.
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Cruickshank, Joanna. Colonial Contexts and Global Dissent. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199683710.003.0013.
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Until late in the nineteenth century, the otherwise fractious universe of Dissent united in affirming Scripture as the supreme religious authority and in exalting the individual conscience as the final interpreter of the Bible’s message. Because of this scriptural fixation, Dissenters contributed disproportionately to the manifestly biblical character of nineteenth-century Anglo-American civilization. It is for that very reason often hard to differentiate a specifically Dissenting history of the Bible from much shared with other Protestants. General cultural influences such as an emphasis on human subjectivity had a lot to do with how Dissenters read their Bibles. The ‘Bible civilization’ to which they contributed was permeated with scriptural phrases and assumptions. Disputes about biblical authority became important because most people were privately committed to the intensive reading of Scripture with the aid of family Bibles. Scripture also lived in public through hymnody and preaching. The Bible featured heavily in political controversy, notably due to disagreements about its place in systems of public education. The tendency to found claims to religious authority on a purified reading of Scripture and to contrast this with the practice of Roman Catholicism was characteristic of Dissent, as was the tendency for those claims to clash. Dissenters divided, for instance, on prophetic interpretation or on whether biblical interpretation needed to be guided by creeds. Conflict over how to interpret the Bible deepened and widened to encompass questions about the character of Scripture itself. Representative early nineteenth-century Dissenters such as Moses Stuart and Josiah Conder held on to unsophisticated if potentially liberal assumptions about the nature of its inspiration but disputes about higher criticism would mount in the wake of Anglican controversies in the 1850s and 1860s. It was striking, however, that these disputes were not as acrimonious in the British Empire as in the United Kingdom or the United States, perhaps because Canadian or Australian Dissenters were more interested in confessional identity and national service. By the end of the century, the expanding terrain of intra-Protestant conflict made it increasingly difficult to discern a unified Dissenting voice. By 1900, it was not as clear as it had once been that ‘the Holy Scriptures are the sole authority and sufficient rule in matters of religion’.
Book chapters on the topic "Contact angle. eng"
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Chaudhary, Ankit, Jagdish Lal Raheja, Karen Das, and Shekhar Raheja. "Fingers' Angle Calculation Using Level-Set Method." In Computer Vision and Image Processing in Intelligent Systems and Multimedia Technologies, 191–202. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-6030-4.ch010.
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In the current age, use of natural communication in human-computer interaction is a known and well-installed thought. Hand gesture recognition and gesture-based applications have gained a significant amount of popularity amongst people all over the world. They have a number of applications ranging from security to entertainment. These applications generally are real time applications and need fast, accurate communication with machines. On the other end, gesture-based communications have few limitations, but bent finger information is not provided in vision-based techniques. In this chapter, a novel method for fingertip detection and for angle calculation of both hands' bent fingers is discussed. Angle calculation has been done before with sensor-based gloves/devices. This study has been conducted in the context of natural computing for calculating angles without using any wired equipment, colors, marker, or any device. The pre-processing and segmentation of the region of interest is performed in a HSV color space and a binary format, respectively. Fingertips are detected using level-set method and angles are calculated using geometrical analysis. This technique requires no training for the system to perform the task.
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Stafford, Pauline. "Chronicles E, /E, and H: The End of the Tradition?" In After Alfred, 297–320. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198859642.003.0014.
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This chapter deals with the last surviving Anglo-Saxon vernacular chronicle, E, produced at Peterborough c.1121, and the last stages of Chronicle /E which lies behind it. The content and palaeography of E place it at Peterborough. Peterborough monastic history is now incorporated into the story, though the result is not a simple ‘house history’. Questions are raised about E’s annals numbered c.1060 onwards, their likely home(s), and the stages of their composition. Work on /E is viewed in the context of burgeoning Latin historiography, with which it has much common ground. The fragment, Chronicle H, is placed in this same world. The networks and contacts invoked to explain patterns of composition and exchange from the mid eleventh century are seen as still relevant. The changing relationship of vernacular chronicling to the court heralds the end of a tradition of chronicling for and by an Anglo-Saxon elite who had disappeared.
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Gautam, Budhayash. "Energy Minimization." In Homology Molecular Modeling - Perspectives and Applications [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94809.
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The energetic state of a protein is one of the most important representative parameters of its stability. The energy of a protein can be defined as a function of its atomic coordinates. This energy function consists of several components: 1. Bond energy and angle energy, representative of the covalent bonds, bond angles. 2. Dihedral energy, due to the dihedral angles. 3. A van der Waals term (also called Leonard-Jones potential) to ensure that atoms do not have steric clashes. 4. Electrostatic energy accounting for the Coulomb’s Law m protein structure, i.e. the long-range forces between charged and partially charged atoms. All these quantitative terms have been parameterized and are collectively referred to as the ‘force-field’, for e.g. CHARMM, AMBER, AMBERJOPLS and GROMOS. The goal of energy Minimization is to find a set of coordinates representing the minimum energy conformation for the given structure. Various algorithms have been formulated by varying the use of derivatives. Three common algorithms used for this optimization are steepest descent, conjugate gradient and Newton–Raphson. Although energy Minimization is a tool to achieve the nearest local minima, it is also an indispensable tool in correcting structural anomalies, viz. bad stereo-chemistry and short contacts. An efficient optimization protocol could be devised from these methods in conjunction with a larger space exploration algorithm, e.g. molecular dynamics.
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Rippon, Stephen. "Regional identities Angles and Saxons?" In Kingdom, Civitas, and County. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198759379.003.0015.
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Writing in the early eighth century, Bede described how three separate peoples— the Angles, Saxons, and Jutes—had settled in Britain some three hundred years earlier, and ever since the genesis of ‘Anglo-Saxon’ scholarship in the nineteenth century archaeologists have sought to identify discrete areas of Anglian, Saxon, and Jutish settlement (e.g. Leeds 1912; 1936; 1945; Fox 1923, 284–95). The identification of these peoples was based upon different artefact styles and burial rites, with most attention being paid to brooches. The degree of variation in the composition of brooch assemblages across eastern England is shown in Table 9.1. Cruciform brooches with cast side knobs, for example, were thought to have been ‘Anglian’, and saucer brooches ‘Saxon’ (although even in the early twentieth century Leeds (1912) had started to doubt the attribution of applied brooches to the West Saxons). In recent years, however, this traditional ‘culturehistorical’ approach towards interpreting the archaeological record has been questioned, as it is now recognized that, rather than being imported from mainland Europe during the early to mid fifth century, regional differences in artefact assemblages emerged over the course of the late fifth to late sixth centuries (e.g. Hines 1984; 1999; Hilund Nielsen 1995; Lucy 2000; Owen- Crocker 2004; 2011; Penn and Brugmann 2007; Walton Rogers 2007; Brugmann 2011; Dickinson 2011; Hills 2011). In early to mid fifth-century England, in contrast, it now appears that Germanic material culture was in fact relatively homogeneous, with objects typical of ‘Saxon’ areas on the continent being found in so-called ‘Anglian’ areas of England, and vice versa. The earliest material from East Anglia, for example—equal-arm, supporting-arm, and early cruciform brooches—are most closely paralleled in the Lower Elbe region of Saxony, with the distinctive ‘Anglian’ identity of EastAnglia onlyemerging through later contact with southern Scandinavia (Hines 1984; Carver 1989, 147, 152; Hills and Lucy 2013, 38–9). Indeed, many elements of the classic suite of early Anglo-Saxon material culture actually developed within Britain as opposed to having been created on the continent (Hills 2003, 104–7; Owen-Crocker 2004, 13), with new identities beingmade in Britain rather than being imported frommainland Europe (Hills 2011, 10).
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Hari, Riitta, and Aina Puce. "Visual Responses." In MEG-EEG Primer, edited by Riitta Hari and Aina Puce, 214–26. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190497774.003.0013.
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This chapter introduces visual evoked responses. Transient VEPs are maximal across the posterior scalp and consist of three main deflections—N75, P100, and N135. Magnetic VEFs also show a prominent occipital response peaking at around 100 ms. Visual stimulation can include light flashes, pattern onset/offsets, pattern reversals and natural images. The extent and eccentricity of the visual stimulus can selectively encompass foveal or extrafoveal regions, or include quadrants, hemifield or the entire visual field. Stimulus attributes such as visual angle, spatial frequency, luminance and contrast greatly affect VEF and VEP amplitudes and latencies. Selective responses in the dorsal and ventral visual streams can be elicited with carefully chosen stimuli. Steady-state responses to periodically varying visual stimuli can be used to frequency-tag different aspects of the visual stimulus.
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Rima, B. K. "Mumps: Epidemic parotitis." In Oxford Textbook of Medicine, edited by Christopher P. Conlon, 769–72. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0080.
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Mumps is an acute, systemic, highly infectious, communicable infection of children and young adults, caused by a paramyxovirus (with an RNA genome). Transmission is by airborne droplet spread. After an incubation period of 14–18 days, typical presentation is with fever, pain near the angle of the jaw, and swelling of the parotid glands. Complications include orchitis, meningitis, and encephalitis. Diagnosis is obvious clinically in cases with a contact history and parotitis, but serological (mumps-specific IgM and IgA) and RNA-based (RT-PCR) tests are used when this is not the case (e.g. the patient presenting with meningitis). Treatment is symptomatic. Prevention is by vaccination, often given as one component of a trivalent mumps/measles/rubella vaccine at 14–16 months of age. A follow-up vaccination is now recommended at 4–5 years of age.
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Aveyard, Bob. "Capillarity, wetting, and surface (interfacial) tension." In Surfactants, 25–52. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.003.0003.
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Capillarity reflects the action of interfacial tension and has been central to understanding intermolecular forces. When a liquid meets a solid surface (with contact angle θ) it forms a meniscus which is associated with the rise/depression of liquid in a capillary tube, hence the term capillarity. Interfacial tensions also determine how a liquid wets and adheres to a solid or another liquid. Liquid menisci are curved, and Young, Laplace, and Kelvin have all thrown light upon the properties of curved liquid surfaces. The Young–Laplace equation relates the pressure difference across a curved liquid interface to both the interfacial tension and curvature of the interface. Interfacial tension also gives rise to a dependence of the vapour pressure (and solubility) of a liquid on the curvature of its surface (e.g. drop radius), as expressed in the Kelvin equation. Common methods for measurement of interfacial tensions are described in an Appendix.
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Bose, Goutam Kumar, Pritam Ghosh, and Debashis Pal. "Analytical and Numerical Modelling of Liquid Penetration in a Closed Capillary." In Process Analysis, Design, and Intensification in Microfluidics and Chemical Engineering, 114–35. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7138-4.ch004.
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The chapter explores the dynamics of liquid penetration in a closed end vertical capillary. This model is very important for impedance spectroscopy methodology where oxidized porous silicon provides an in vitro medium, and one important criteria of this methodology is the liquid penetration depth inside the silicon pores as the impedance is greatly affected by this penetration depth. This problem is also important in order to understand how the presence of entrapped air inside a micro pore can influence the dynamics of capillary flow. For this purpose, the model is studied both analytically and numerically. In this study, different pore size (500 nm and 2 µm diameter) with equal pore depth (~10 µm) have been used. Finally, the analytical solution is compared with the numerical results. In addition, the linearization of the system is also investigated and found the critical viscosity of which demarcates the over-damped and under-damped regimes. Further, this study is extended by incorporating the dynamic contact angle effects on the meniscus dynamics.
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Dixon, Dan. "Pattern Languages for CMC Design." In Handbook of Research on Socio-Technical Design and Social Networking Systems, 402–15. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-264-0.ch027.
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Three decades ago the concept of pattern languages were introduced in the field of architecture and they have since become widely used in object-oriented programming and HCI. However their use in computing is divergent from Alexander’s original goals on two main points. Firstly, they were largely intended to describe the spaces formed by or for human activities and events. Secondly, they were intended as a way for professionals and lay people to communicate whilst designing buildings. This chapter suggests that the socio-technical design of social software should rediscover both these principles, firstly in a fuller appreciation of the wider human angle, and secondly in the participative design approach. Indeed, a pattern language approach within a socio-technical framework seems the ideal way to design the next generation of computer-mediated communication applications, as it will do so in a social context and in partnership with end users.
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Rippon, Stephen. "The boundaries of early medieval kingship." In Kingdom, Civitas, and County. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198759379.003.0018.
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In the past the study of early medieval kingdoms has mostly been a singledisciplinary activity based upon the extremely limited documentary sources, with boundaries back-projected from much later evidence (e.g. Bailey 1989, fig. 8.1). What is presented in this study, in contrast, is an attempt to have a more archaeologically and landscape-based discussion that includes using the distributions of cultural indicators such as artefact types, architectural forms, burial practices, and the locations of particular sites that appear to have been positioned in liminal locations. Three phases in the development of these kingdoms can be distinguished: • The fifth to sixth centuries (emergent kingdoms): the period of Grubenhäuser and Anglo-Saxon burials associated with a suite of material culture showing marked regional affinities. Anglo-Saxon kingdoms existed by the end of this period, and a broad consensus has emerged that they were formed through the amalgamation of a series of smaller regiones (e.g. Arnold 1988; Bassett 1989a; Yorke 1990; Scull 1993; 1999; Harrington and Welch 2014). This model—which Bassett (1989b) has compared to a football knock-out competition—is, however, based largely upon the fragmentary and very partial documentary record (see Chapter 7), and it does not explain the close correspondence of the boundaries between the fifth- to sixth-century socio-economic zones spheres identified here and those of the Iron Age and Roman periods. • The seventh and eighth centuries (mature kingdoms): a new suite of material culture (e.g. East Anglian and East Saxon coinage, and Ipswich Ware) whose circulation in part appears to have been restricted to the polities within which they were produced. The authority of the East Saxon kings had started to decline during the latter part of this period, although East Anglia survived. • The ninth century (the declining kingdoms): the East Saxon kingdom virtually disappeared and become a territory within Wessex. The distributions of later eighth- and ninth-century inscribed coinage, and distinctive artefact types such as silver wire inlaid strap ends, suggest that the East Anglian socio-economic sphere, and the kingdom that was based upon it, survived within the same boundaries that had emerged by the fifth and sixth centuries until it was overrun by the Danes in the 870s.
Conference papers on the topic "Contact angle. eng"
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McKeel, Charles A. "Effects of Package Content Position on Slap-Down Angle." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-26067.
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As part of regulatory requirements, shipping packages must be able to withstand specified height drop accidents under a worst case orientation and configuration. The burden of justifying worst case orientation and configuration is placed on the package applicant. One of the drop cases to consider is slap-down, where the package is dropped at a shallow angle (eg, nearly horizontal). Due to the shallow angle, the initial impact at one end of the package accelerates the opposite end into the target surface at greater than the net drop velocity. The dynamics of the slap-down condition are modeled using simplified rigid-body dynamics to provide test engineers with a basis for establishing a suitable package content placement that could maximize the slap-down condition.
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Pesse, Ana V., Gopinath R. Warrier, and Vijay K. Dhir. "Experimental Study of the Gas Entrapment Process in Closed-End Microchannels." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60296.
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Earlier studies have shown that for cavities present on any heater surface to become active nucleation sites during boiling, they should entrap gas. The liquid penetrates the cavity due to the capillary and surface forces, but the exact physical mechanisms have not been fully quantified. The physical mechanisms of the gas entrapment process in closed-end microchannels, representing nucleation sites, are investigated in this study. Aside from the fluid properties, the width, length and depth of the cavities, as well as the static contact angle of the test liquid with the solid are considered as main parameters that influence the gas entrapment process. Test pieces consisted of micromachined silicon dices with glass bonded on top. Widths of 50, 30, 15 and 5μm were chosen based on size distribution probability. The mouth angle was 90° in all cases. Test pieces were held horizontally under a microscope equipped with a CCD camera. A drop of liquid was placed at the entrance of the microchannel and capillary and surface forces drive the liquid into the microchannel. Experiments show two main filling behaviors: (1) A uniform meniscus forms at the entrance and moves inwards, (2) Two menisci: one at the entrance and the other at the closed end of the microchannel. In some cases droplet formation at the walls was observed. A single meniscus typically forms for higher contact angles, while two menisci form for lower contact angles. In all cases, after a sufficient time interval (hours to days) the microchannel was completely flooded. In general, for a given depth, wider microchannels take longer to fill. Surface cleanliness and fabrication process also play a role in modifying the contact angle and hence the time taken to fill the microchannel. A comparison of the interface advancement in the microchannel with a simple mass diffusion model shows reasonable agreement.
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Leeladhar, Rajesh, Wei Xu, and Chang-Hwan Choi. "Evaporation of Nanoparticles Droplets on Nanoporous Superhydrophobic Surfaces." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10773.
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In this paper, we experimentally studied the evaporative behavior of the nanofluid droplets (fluid containing metal nanoparticles) on nanoporous superhydrophobic surfaces. Uniformly dispersed in water, gold chloride (AuCl3) nanoparticles of varying sizes (10–250 nm) and concentrations (0.001–0.1% wt) were tested as nanofluids. Porous anodized aluminum oxide (AAO) with a pore size of 250 nm was tested as a nanoporous superhydrophobic surface, coated by a self assembled monolayer (SAM). During the evaporation in a room temperature and pressure, the evaporation kinetics (e.g., contact angle, contact diameter, and volume) of the nanofluid droplets was measured over time by using a goniometer. In the beginning, the initial droplet contact angles were significantly affected by the nanoparticle sizes and concentrations such that as the concentration increased, the initial contact angle decreased, which was more pronounced at larger particle sizes. During evaporation, despite the different particle sizes and concentrations, there were two distinct stages shown, especially for the change of contact angles, i.e., gradual decrease in the beginning, followed by rapid decrease in the end. No remarkable wetting transition from de-wetting (Cassie) to wetting (Wenzel) state was shown during the evaporation. Evaporation rate was influenced by nanoparticles such that it was significantly mitigated with the nanofluid droplet of the highest concentration (0.1% wt). The scanning electron microscope (SEM) images show that the ring-like dry-out pattern forms after the evaporation of nanofluids with lower concentrations (0.001%, 0.01% wt), whereas the one with higher concentrations (0.1%wt) forms a uniformly distributed pattern. These results demonstrate that nanoparticle sizes and concentrations make significant effects on interfacial phenomena in droplet evaporation on nanostructured surfaces, which will impact many engineering applications and system designs based on droplets such as microfluidics and heat transfer.
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Mukoyama, Hiroshi, Shigeyuki Shimachi, and Yoshihide Hakozaki. "Contact Pressure Estimates of Tooth Surfaces of Gear Couplings." In ASME 2000 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/detc2000/ptg-14452.
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Abstract Recent demands for gear couplings are to reduce the backlash and to increase the shaft angle limit. On coping with these demands, the tooth contact pressure is recognized as the trade-off problem. In the traditional estimation of tooth contact pressure, the deflection of tooth is calculated by using the formula for spur gear that has long contact bearing in the face width direction, although gear coupling has it in the tooth depth direction. And, the Hertz depression of the tooth surface is estimated as that of the infinite plane. Additionally, the traditional methods don’t consider about the edge contact on the tip or end of tooth. A successive approximation method is established to find the load distribution on the mating teeth surfaces. As for the effect of the edge contact on the tip or end of tooth, it is cleared that the contact pressure distribution deforms itself severely, but the maximum pressure is almost constant. The expressions estimating the maximum pressure and the displacement of tooth base are constructed for 6 parameters as follows; total load coefficient, relative curvature of teeth surfaces, tooth module, ratio of tooth height to face width, angle of tip contact and deviation of end contact.
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Halloran, Jason, Craig Bennetts, Robb Colbrunn, Tara Bonner, Ahmet Erdemir, and Jack Andrish. "Evaluation of Patellofemoral Contact Mechanics as a Function of Quadriceps Load and Flexion Angle." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80303.
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Patellofemoral complications are the single largest reason for knee related clinical visits. In spite of this, development of robust clinical treatments in this area remains a challenge [1]. Quantifying joint response across a wide range of conditions may lead to interventions specifically targeting desired or “normal” function. Previous patellofemoral studies often looked at joint mechanics as a function of specific quadriceps loaded flexion (e.g. deep knee bend) and/or during snapshots of loading representative of lifelike scenarios, e.g. gait, stair climb, etc. [2]. Sensitivity studies have been performed for these expected conditions [3,4] providing insight on the relationship between joint loading, geometry and potential contact mechanics. While patellofemoral biomechanics studies are prevalent, few, if any, have attempted to quantify joint response to systematic changes of two of the primary indicators of joint mechanics, namely quadriceps load and knee flexion. The overall joint response resulting from this type of approach could help quantify an envelope of natural function and also serves as an ideal data set for future computational model development. Once developed, probabilistic exploration of inherent uncertainties could be accomplished through a complimentary in vitro and in silico approach, offering quantification and classification of structure-function relationships. As a preliminary step, the goal of this study was to relate in vitro joint response, in terms of kinematics and contact mechanics, to systematic changes in knee flexion angle and quadriceps loading for a single specimen. Results from this study will offer insight into patellofemoral mechanics across a range of expected input and also serves as a starting point for future hypothesis driven studies.
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Caruntu, Dumitru I., and Ricardo Moreno. "Knee Contact Characteristics During Drop Landing Exercise." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67614.
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This work investigates the human leg joint contact characteristics during a drop-landing exercise. The contact characteristics consist of tibio-femoral contact forces and contact point, and hip contact forces. An inverse dynamics 2-D model of human leg is used on this ballistic task in order to simplify computation. Experimental data used show a maximum of 100 degrees of flexion angle and ground reaction forces up to 4 times the body weight. All contact forces show a pattern in which they reach large magnitudes at the beginning of landing, decreasing as the subject end the exercise with a standing position.
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Meggiolaro, Marco A., Guglielmo Scriffignano, and Steven Dubowsky. "Manipulator Calibration Using a Single Endpoint Contact Constraint." In ASME 2000 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/detc2000/mech-14129.
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Abstract Most manipulator calibration techniques require expensive and/or complicated pose measuring devices, such as theodolites. This paper investigates a calibration method where the manipulator endpoint is constrained to a single contact point and executes self-motions. From the easily measured joint angle readings, and an identification model, the manipulator is calibrated. Adding a wrist force sensor allows for the calibration of elastic effects due to end-point forces and moments. Optimization of the procedure is discussed. Experimental results are presented, showing the effectiveness of the method.
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Leeladhar, Rajesh, Wei Xu, and Chang-Hwan Choi. "Effects of Nanofluids on Droplet Evaporation and Wetting on Nanoporous Superhydrophobic Surfaces." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18551.
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In this paper, nanofluid droplets (fluid containing metal nanoparticles) were subjected to evaporation on a nanoporous superhydrophobic surface to study the effects of nanoparticles on evaporation kinetics, wetting dynamics, and dry-out patterns. Metal nanoparticles (gold chloride) of three different sizes (10, 100, and 250 nm) at three different concentrations (0.001, 0.01, and 0.1% wt) were tested as nanofluids, uniformly dispersed in deionized water. Anodized alumina membranes (200 nm in pore diameter) were tested as nanoporous superhydrophobic surfaces, coated with a self assembled monolayer (SAM). During the course of evaporation in a room condition, the change of a contact angle, contact diameter, height, and volume was measured by a goniometer and compared with that of the base fluid (water) taken as a control. The initial equilibrium contact angle of the nanofluids was significantly affected by the nanoparticle sizes and concentrations. During evaporation, the evaporation behavior for the nanofluids exhibited a complete different mode from that of the base fluid. In terms of a contact angle, nanofluids showed slower decrease rate than base fluid. Nanofluid contact diameter remained almost a constant throughout evaporation with a slight change only at the very end of evaporation stage, whereas the base fluid showed a sequence of constant, increase, and mixed states of increase/decrease behavior. The nanofluids also showed a clear distinction in the evaporation rates, resulting in slower rate than base fluid. The variation of the nanoparticle sizes and concentrations did not make significant difference in the evaporation rate within the tested conditions. No abrupt change in a contact angle and diameter was observed during the evaporation, suggesting that no remarkable wetting transition from Cassie (de-wetting) to Wenzel (wetting) state occurred. The scanning electron microscope (SEM) images of the deposited nanoparticles after complete evaporation of solvent showed unique dry-out patterns depending on nanoparticle sizes and concentrations, e.g., a thick ring-like pattern with larger particle sizes while a uniformly distributed pattern with smaller particles at higher concentrations.
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Rahman, M. A., and A. M. Jacobi. "Wetting Behavior and Drainage of Water Droplets on Microgrooved Brass Surface." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64255.
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In the present study, we report the contact angle hysteresis and drainage behavior of water drops on a number of brass surfaces with parallel microgrooves and compare them to the flat baseline surfaces. Parallel micro-grooves with different groove dimensions are fabricated by micro end-milling process without any modification of the surface chemistry. Advancing and receding contact angles in both parallel and perpendicular direction of the grooves and also the drainage behavior of water droplets on the microgrooved surfaces is found to be considerably affected by change in groove geometry parameters. Very high hysteresis is observed for both low (< 0.2) and high aspect ratio (> 0.7) of grooves and also for surfaces with lower groove spacing due to the droplets being in a Wenzel state. For intermediate aspect ratio (0.25–0.70) and larger spacing of the grooves, droplets remain in a Cassie state and the hysteresis is lower in both directions than that on the flat surfaces. Variation of critical sliding angle (angle at the point of incipient sliding of water droplets due to gravity) with groove geometry is investigated for a range of water droplet volume of 15 to 75 μl. Droplets of all volumes are found to slide much more readily on grooved surfaces than when placed on the flat baseline surfaces. Height and spacing of the grooves are also found to have significant influence on the sliding of the water droplets, as critical inclination angle decreased with groove height and increased with groove spacing. The results from this study may be useful in a broad range of applications where water retention plays an important role.
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Barona, David, and A. Amirfazli. "A Robust Superhydrophobic Surface for Digital Microfluidics." In ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58159.
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Digital microfluidics depends on efficient movement of individual drops for a variety of tasks, e.g. reagent delivery, mixing, sampling, etc. Superhydrophobic (SH) coatings generally show high repellency and low adhesion for a variety of liquids. Therefore, SH coatings can provide for an efficient drop delivery and hence low energy requirements for a fluidic chip. However, wide application of such coatings is hampered by fragile nature of such coatings to date. A new SH coating is developed that addresses the fragility challenge of such coatings. It is based on application of nanoparticles to fluoropolymers. The mechanical stability, wear resistance and durability under prolonged liquid exposure of this new coating is discussed. It is shown that the new SH coating can maintain high contact angles, low contact angle hysteresis needed for drop mobility under adverse conditions/application of digital microfluidic devices. The developed SH coating can also be sprayed onto various surfaces, including glass used in traditional lab-on-chip (LOC) devices, or even paper for enabling novel Lap-on-paper (LOP) devices.