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1
Sood, Eeshani. "Determination of diffusion coefficient for unsaturated soils." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2318.
Full textAbstract:
The structures constructed on unsaturated soils are damaged by the movement of
the soil underneath. The movement is basically due to the flow of moisture in and out of
the soil. This change in moisture also affects the strength of the soil, thus resulting in
failure of slopes of embankments constructed with these soils. Therefore, it is very
important to study the diffusion properties of unsaturated soils. Study of the diffusion
properties requires the determination of the diffusion coefficient (/).
In this thesis improvements in the drying test, originally proposed by Mitchell
(1979), have been discussed. The study also involves defining the evaporation coefficient
(he) which has been ill-defined in previous research work. The flow through unsaturated
soils is non-linear but due to the complexity involved it has been simplified to a linear
problem. The nonlinear behavior has been studied during this research. Therefore,
certain refinements have been applied in the determination of the diffusion coefficient.
The laboratory procedure followed involves measuring the soil suction along the
length of the sample and at different times using thermocouple psychrometers. The
evaluation of the evaporation coefficient (he) has been made an integral part of the
procedure. The diffusion coefficient is determined using the curve fitting procedure of
Aubeny and Lytton, 2003.
2
Wang, Yang. "CdS Reflection Coefficient Determination via Photocurrent Spectroscopy." Bowling Green State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1219593815.
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Tothill, M. H. "Turbine blade heat transfer coefficient determination using optical pyrometry." Thesis, Cranfield University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352954.
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4
Baker, Stephen. "Optimal determination of the optical coefficients from scattering media." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268794.
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Acinan, Sezen. "Determination Of Runoff Coefficient Of Basins By Using Geographic Information Systems." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609522/index.pdf.
Full textAbstract:
Turkey has very different geomorphologic, hydrologic and climatic conditions, so the runoff coefficient should be different from one basin to another. But only one constant value, which is 0.37, is being used for all the basins in Turkey. In this thesis, monthly, seasonal and annual runoff coefficients of 48 sub-basins in western and southern part of Anatolia are determined by using synchronous and average rainfall, runoff data of 26 year record period. Their temporal and spatial distributions are investigated. The relationship between the basin parameters and the runoff coefficient are also examined. Some of the basins have unrealistic large runoff coefficients, therefore excluded from the analyses.
The basin boundaries and parameters are determined by using Geograhic Information System (GIS), and areal average precipitations are found by a program written in visual basic language that uses ArcObjects. The Box-Cox transformed data are used in regression analysis. There are a number of dams in the region, which affect the natural flow. Such streams are found and their sub-basins are not used in the analyses. The results revealed that there is not a strong the relationship between the basin parameters and annual and seasonal runoff coefficients for the whole region, but there are significant relations between them for some basins.
6
Zeywar, Nadim Shukry. "Water use and crop coefficient determination for irrigated cotton in Arizona." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185887.
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Crop coefficients (K(c)) are a useful means of predicting how much water is needed for irrigating a crop. The crop water stress index (CWSI), on the other hand, is a means of knowing when to irrigate. Two field experiments were conducted during the summers of 1990 and 1991 at Maricopa Agricultural Center and Marana Agricultural Center, respectively, to evaluate water use (evapotranspiration, ET) of different cotton varieties, to develop crop coefficients for cotton grown in the state of Arizona, and to evaluate empirical and theoretical crop water stress indices under field conditions. For the 1990 experiment, ET from the cotton variety DPL 77 was obtained using soil water balance (SWB) and steady state heat balance (SSHB) techniques. For the 1991 experiment, ET from two cotton varieties (DPL 20 and Pima S-6) was estimated using the Bowen ratio energy balance (BREB) method and the steady state heat balance method. Reference evapotranspiration (ETᵣ) was obtained from weather stations located close to the experimental plots. Average daily ET from the SSHB measurements ranged from 8.24 to 15.13 mm and from 10.34 to 12.12 mm for the 1990 and 1991 experiments, respectively. Total ET from the SWB was approximately 19% less than the total ET estimated by the SSHB. Total ET from individual plants was well correlated with average stem area over the evaluation periods. Daily ET from the two cotton varieties (DPL20 and Pima S-6) was approximately similar when irrigation conditions were the same, but differed later by as much as 48.4% as irrigation continued for the variety Pima S-6 only. Daily ET from the BREB measurements and ETᵣ were used to develop a crop coefficient curve for cotton grown at Marana, Arizona, which had a maximum smoothed value of 1.21. A critical value of CWSI equal to 0.3 was obtained by observing the pattern of the CWSI values over well-watered and drier conditions, and from previous research. Using the developed crop coefficient curve and the CWSI should provide a useful means of scheduling irrigation for cotton grown under climatic conditions similar to those at Marana, Arizona.
7
Kunene, Thokozani Justin. "Determination of the head loss coefficient of closely spaced pipe bends." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2519.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.Space limitation in ships and the complex pipe layouts in chemical, mineral and food processing plants lead to the employment of closely spaced bends. The limited information regarding the head loss coefficient of pipe bends orientated as bend-spacer-bend has led pipeline designers to treat them as isolated bends with the same loss coefficient. Thus, to calculate the head loss in the piping system would simply involve summing the head loss coefficient of bends and neglecting their configuration. This practice causes inaccurate computation of head losses in the system. In this study a computational model is developed for the head loss coefficient of closely spaced pipe bends. This is then supported by experimental verification. A more accurate but still simple and easy to use empirical correlation is derived. The empirical correlation is established and the data presented under isothermal conditions for turbulent flows in a range 7.3x104 ≤ Re ≤ 5.8x105 and a spacing ratio of 1D ≤ L/d ≤ 10Dand curvature ratio of 3 ≤ rc/d ≤ 5. Using ANSYS® CFX® 11, a commercial computational fluid dynamics (CFD) package, the fluid domain representing two 900 smooth pipe bends separated by a short pipe was solved and the mechanisms causing the head loss coefficient were explored by using the CFD results to visualise the fluid flow structure/pattern. The computational model was validated by comparing the head loss coefficient of a single bend and the model was found to be sound. The experiments conducted in the built test facility using smooth pipes showed similarities in the trends between the CFD work and the published data and they were to be found have a similar trend. The experiment had shown results that agree to the findings from literature.
8
Gold, H. David. "Water use and crop coefficient determination for irrigated winter wheat in Arizona." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/192128.
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Estimates of evapotranspiration (ET) were irrigated winter wheat in the spring of 1988 9 made for based on measurements of latent heat flux using Bowen ratio systems at the University of Arizona's Maricopa Agricultural Center (MAC). Data were examined over a 132 day period. For the same time period, reference ET estimates were made in the same region using a modified Penman equation based on data from the Arizona Meteorological Network (AZMET). A comparison of ET estimates for 118 days prior to wheat senescence shows excellent agreement (r^2 = 0.94). This implies that a simple crop coefficient can be used as a basis for irrigation scheduling for winter wheat grown under climatic conditions similar to those at MAC in 1988. In addition, the ET estimates were used to test the validity of a previously determined crop coefficient for winter wheat based on heat units and to assess current groundwater allocations in Arizona.
9
Martin, E. C., S. W. Winans, and D. Esquerra. "Determination of Heat Unit Based Crop Coefficient for Alfalfa in Western Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/201439.
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Alfalfa is the second largest production crop grown in Arizona with an estimated 150,000 acres of production in 1993. Water requirements for alfalfa have been estimated at 6 acre-feet per year. These two facts together make it imperative that data be gathered to help growers apply their irrigation water efficiently while maintaining their yields. In 1994, a study was initiated in the Parker Valley region of La Paz County, Arizona, to measure daily water use in alfalfa. Two sites were chosen for measurement: one site was a surface irrigated field located at the Quail Mesa Farm; the second site was a surface irrigated field located on the Colorado River Farm. The two sites were chosen to give a contrasting schedule of irrigation and allow for data collection at differing times throughout the year. Nine neutron probes were installed in each field, three 113 in from the head, three in the center, and three 113 in from the tail on one field at each location. Neutron probe readings were taken at 18", 30", 42", and 54" depths below the soil surface to measure soil moisture from 1' -2', 2' -3', 3'-4', 4' -5'. The soil moisture for the top foot was determined by gravimetric sampling. The data gathered by this study was used to compare with data used in AZSCHED, a computerized irrigation scheduling program. With this data, determination of alfalfa water used based on heat units after cutting was made to help growers better use their irrigation water.
10
Oliveira, Aureo Silva 1965. "Determination of head lettuce crop coefficient and water use in central Arizona." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282779.
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The assessment of crop evapotranspiration (ET) has received intensive research due to its critical role in irrigation management and water conservation studies. Because weather conditions largely determine ET, various methods based on meteorological factors have been developed to estimate ET rates. In order to accommodate the concept of reference crop ET (ETo), evaluation of weather data quality has been addressed. In this research, 9 year (1989-1997) weather data from the AZMET weather station at the Maricopa Agricultural Center were used to compare daily and 10 day average ETo estimated by the Hargreaves (HARG), FAO 24 Penman (FAOP), and FAO Penman-Monteith (FAOPM) methods. Before ET calculation, the weather data were evaluated for the influence of aridity at the weather station site and sensor calibration/malfunctioning problems. Corrections were made on temperature and solar radiation data. Reference ET as reported by the AZMET was also considered for comparison purposes. In general, the weather data correction decreased ETo estimates 18.3%, on average. The highest reduction (23.5%) was obtained with the FAOPM method. When this method was used as the standard for ETo estimate comparison, the FAOP method corrected for site aridity ranked first as predictor of ETo despite its tendency for overestimation. At the Maricopa Agricultural Center, a two year field research (Fall-Winter of 1996/97 and 1997/98) was carried out to derive head lettuce (Lactuca sativa L.) crop coefficient (Kc) and to investigate the effects of ETo method in the shape and values of the crop coefficient curve. For the periods of low crop ET, the 2 year (Kc) from the HARG, FAOP, and FAOPM methods did not differ significantly. However, in the peak demand period, crop coefficients derived from the three methods peaked at different values. The predicted peak (Kc) was 0.87, 0.72, and 0.82 for the HARG, FAOP, and FAOPM methods, respectively. These results reflect the tendency of ETo underestimation by the HARG method and overestimation by the FAOP method under and conditions. Crop coefficients derived in the 96/97 growing season were then used to investigate the effects of (Kc) and ETo mismatching in the water use and yield of lettuce during the 97/98 growing season. To reach such objectives, an experiment design in Latin square with four replications and four treatments was carried out. Differences in seasonal water depth were as high as 33 mm among treatments. The analysis of variance revealed that the treatments did not induce lettuce marketable yield statistically different at the 5% significance level.
11
TICONA, EPIFANIO MAMANI. "EXPERIMENTAL DETERMINATION OF THE HEAT TRANSFER COEFFICIENT IN AN ICE SLURRY GENERATOR." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3765@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOUm sistema térmico de armazenamento da energia com pasta de cristais de gelo foi desenvolvido para aplicações de condicionamento de ar e resfriamento de processos. O sistema usa um evaporador orbital de haste, um trocador de calor vertical do tipo tubo e carcaça com intensificação mecânica de transferência de calor. A pasta de gelo é produzida continuamente sem acumulação no evaporador e é compatível com unidades condensadoras convencionais, tanques de armazenamento e bombas. Soluções aquosas diluídas ou soluções inorgânicas de salmoura promovem a formação de cristais de gelo, e o gelo líquido resultante pode ser bombeado ou por gravidade alimentar um tanque de armazenamento. O circuito hidráulico de refrigeração (carga térmica) pode ser desacoplado da produção do gelo utilizando-se o tanque de armazenamento. O armazenamento de gelo líquido fornece temperaturas consistentemente baixas à medida que se derrete o gelo, que por sua forma pode ser derretido também muito rapidamente. Com suas altas temperaturas características de evaporação e elevados fluxos do calor, os sistemas de geração de gelo líquido apresentam potencial para reduzir significativamente os custos de capital inicial e operação, quando comparados com tecnologias de sistemas estáticos de gelo ou ice harvesting.
New ice crystal slurry thermal energy storage (TES) system has been developed for both HVAC and process cooling applications. The system uses an orbital rod evaporator (ORE), a vertical shell-and-tube heat exchanger with mechanical heat transfer augmentation, as a dynamic ice maker to generate liquid ice. Ice forms continuously without accumulation in the ORE and is compatible with conventional condensing units, storage tanks, and pumps. Dilute glycol or inorganic brine solutions promote formation of ice crystals, and the resulting liquid ice may be pumped or gravity fed to a storage tank. The cooling load circuit can be hydraulically decoupled from ice production at the storage tank. Stored liquid ice provides consistently low solution supply temperatures over significant portions of the ice melt period and may be melted very rapidly. With its characteristic high evaporator temperatures and high heat fluxes, ORE TES systems have the potential for significantly lower capital and operating costs than static ice or ice harvesting technologies.
12
LAGOGUEZ, CORINNE. "Determination des pka et logp des produits peu solubles dans l'eau." Paris 11, 1993. http://www.theses.fr/1993PA114097.
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VINAGRE, HARRY T. MAIA. "EXPERIMENTAL DETERMINATION OF THE HEAT TRANSFER COEFFICIENT IN DUCTS OF ELLIPTICAL CROSS SECTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1987. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33283@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORDeterminou-se experimentalmente o coeficiente local de troca de calor, para o escoamento turbulento interno, em tubos de seção transversal elíptica. As condições de contorno impostas foram, temperatura constante na parede e entrada abrupta, com canto vivo, em uma placa plana. Foram obtidos resultados na região de entrada e na região desenvolvida, cobrindo a faixa de número de Reynolds de 7 000 a 60 000. Foram investigadas as razões de aspecto 0,12, 0,25 e 0,5 e os resultados, comparados com os encontrados na literatura para placa plana e tubo circular. Uma diferença máxima de 16 por cento, foi encontrada em relação aos resultados para tubo circular. Portanto, a utilização de tubos elípticos em trocadores de calor é, em geral, vantajosa do ponto de vista térmico.
Experiments were performed to determine local heat transfer coefficients for the turbulent flow in a duct with elliptical cross section. The boundary conditions imposed were isothermal wall and abrupt-contraction at the entrance built into a large wall. Both entrance-region and fully-developed results were obtained, whereas the Reynolds number was varied in the overall range 7,000-60,000. The aspect ratios 0.12, 0.25 and 0.5 were investigated and the results compared with the ones for parallel planes and for circular tubes, found in the open literature. The measured heat transfer coefficients displayed a maximum deviation of 16 percent relative to the results for the circular tube. Therefore, using elliptical ducts in heat exchangers is in general advisable as far as heat transfer is concerned.
14
Bandyopadhyay, Deep Becker Bryan R. "Determination of heat transfer coefficient and correlation of dimensionless number for freezing of foods." Diss., UMK access, 2004.
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Thesis (M.S.)--School of Computing and Engineering . University of Missouri--Kansas City, 2004."A thesis in mechanical engineering." Typescript. Advisor: Bryan R. Becker Vita. Title from "catalog record" of the print edition Description based on contents viewed Feb. 22, 2006. Includes bibliographical references (leaves 100-104). Online version of the print edition.
15
Jenkin, Lance. "Application of cepstral techniques to the automated determination of the sound power absorption coefficient." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/16913.
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Includes bibliographical references.This thesis builds on research by Bolton and Gold, who developed the theory of using cepstral analysis to determine the absorption coefficient of elastic porous materials. Jongens, in his Masters thesis, applied this technique to determine the absorption coefficient of asphalt samples mounted in a sample holder at the end of a tube. Jongens and others identified numerous factors that introduced uncertainties into the measurement. These uncertainties fall into two main categories. The first deals with the influences that the links of the measurement chain have on the ability to separate the incident and reflected signal. The second deals with the influence of the air leakage between the tube and the surface under measurement in-situ. This thesis deals with the first category. The objectives of this project are to continue the work of Jongens, to produce an apparatus that can rapidly determine the sound power absorption coefficient by a non-skilled operator in a noisy environment. The results should correlate closely with the standardised impedance tube method, within 0.05 over the range 200 Hz to 2000 Hz. The constraint that the apparatus be usable by a non-skilled operator means that little or no calibration should be required, nor should the microphone need to be handled. This thesis presents a survey of related methods used to determine the sound power absorption coefficient. Theory of the cepstral technique is discussed, along with methods that could be used to improve the accuracy of the technique. Excitation signals that could be used with the cepstral method are put forward. The Inverse Repeat Sequence (IRS) was used to excite the system. It was chosen for its high noise immunity, as well as its complete odd-order non-linearity immunity. Sources of uncertainties from the links of the measurement chain are considered and methods to overcome them are presented. Issues that arise from liftering - cepstral equivalent of windowing - are then highlighted. The apparatus for the cepstral technique and method of standing wave ratios used to determine the absorption coefficient is given. The results obtained using the cepstral technique are correlated with the impedance tube results. It was found that the cepstral method correlates closely with the impedance tube over the range of 200 Hz to 2000 Hz for a wide variety of samples. The apparatus was developed to be used by a non-skilled operator, only requiring the press of a button to perform the measurement. With the high noise immunity of the IRS signal, the measurement could be carried out in a noisy environment.
16
Han, Han. "Determination of Flow Stress and Coefficient of Friction for Extruded Anisotropic Materials under Cold Forming Conditions." Licentiate thesis, KTH, Production Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1498.
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The work material in metal working operations always showssome kind of anisotropy. In order to simplify the theoreticalanalysis, especially considering bulk deformation processes,anisotropy is usually neglected and the material is assumed tobe isotropic. On the other hand, the analysis that consideredthe influence of anisotropy seldom incorporates the influenceof friction. For predicting the material flow during plasticdeformation and for predicting the final material properties ofthe product, adequate descriptions of both flow stress curvesand coefficients of friction have to be developed.
In the present work a number of experimental methods fordetermining the anisotropy have been utilized and compared:Yield loci, strain ratios (R-values) and establishing flowstress-curves in different directions. The results show thatthe yield loci measurements are weak in predicting anisotropywhen the material strain hardening is different in differentdirections. It is concluded that also the strain ration(R-value) measurements are unreliable for describinganisotropy. The most trustable and useful results were foundfrom multi-direction determinations of the flow stresses.
Three typical cases of ring upsetting conditions wereanalyzed by theory (3D-FEM) and experiments:
An anisotropic ring, oriented 900 to the axis ofrotational symmetrical anisotropy. The friction coefficientwas the same in all directions
An isotropic ring. The friction coefficient was differentin different directions
An anisotropic ring oriented 00 to the axis of rotationalsymmetrical anisotropy. The friction coefficient was the samein all directions
The cases 1) and 2) reveal that the influence of anisotropyon the ring deformation is quite similar to that obtained bychanging the frictional condition. The case 3) exposes that ifthe material flow caused by anisotropy is incorrectly referredto friction, the possible error of the friction coefficient canbe as high as 80% for a pronounced anisotropic material. Amodified two-specimen method (MTSM) has been establishedaccording to an inverse method. Experiments were carried ascylinder upsetting. Here both ordinary cylinders were used aswell as so-called Rastegaev specimen. Also plane straincompression tests were utilized. The results show that MTSM isable to evaluate the validity of a selected mathematical modelwhen both the friction coefficient and the flow stress areunknown for a certain process. MTSM can also be used toestimate the friction coefficient and flow stress provided thatthe selected mathematical model is adequate.
Key words:Anisotropy, friction coefficient, flowstress, modified two-specimen method and FE-analysis
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Thakur, Anshuman Bramhanand. "Determination of diffusion coefficient through laboratory tests and analytically validating it using empirical relations for unsaturated soils." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2713.
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Soil suction is one of the most important physical variables affecting the soil engineering
behavior, moisture content. Suction has a major controlling influence on soil shear strength. The
moisture diffusivity properties of unsaturated properties of soils exert a critical influence on the
depth to which seasonal variations of moisture and suction at the ground surface extend into the
soil mass. Hence, a study of moisture diffusion coefficient is pivotal.
In this research the drying test originally proposed by Mitchell (1979) has been validated
by back calculating the moisture diffusion values using the empirical relation established by
Lytton (2003).
The non-linear flow through unsaturated soils has been simplified to a linear problem for
simplicity in this study. Owing to this simplification, certain refinements have therefore been
applied in the determination of diffusion coefficient. Thermocouple psychrometer was used to
measure the soil suction along the length of the sample and at different times in the laboratory.
Initial suction measurements were done using the filter paper test. Curve fitting procedure
established by (Aubeny and Lytton, 2003), has been used for the determination of the diffusion
coefficient. Analytical validation of the moisture diffusion coefficient, required coefficient of
permeability, ??k??, slope of suction water characteristic curve ??S?? and air entry value ??ho?? as the
major input parameters.
Mitchell (1979) assumed the value of ??ho?? to be 100 cm. In this research air entry value,
??ho?? has been re-evaluated and it comes out to be higher than the pre estimated value. The value
of slope of suction water characteristic curve, ??S?? obtained from pressure plate tests, compares
well to the empirical equation of Lytton (2003).
The results of moisture diffusion coefficient obtained from the empirical equation come
out in the same range as obtained from the refined Mitchell??s (1979) drying test. The refinements
includes introduction of constant temperature environment. Owing to the least variation in
temperature, more reliable and reproducible data was obtained.
The range of moisture diffusion coefficient, ??-values obtained from empirical equation,
comes out to be coherent with the laboratory data. Hence, it can be concluded that the research
was successful.
18
Steitz, Bettina [Verfasser]. "Experimental determination of the partitioning coefficient of nopinone as a marker substance in organic aerosol / Bettina Steitz." Wuppertal : Universitätsbibliothek Wuppertal, 2013. http://d-nb.info/1037090624/34.
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GRASSER, CHRISTOPHE. "Le coefficient de partage octanol-eau : mise au point d'une nouvelle methode de determination par flow injection analysis (fia)." Strasbourg 1, 1994. http://www.theses.fr/1994STR15054.
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Hyland, Raymond A. "Soil moisture determination using a multisensor capacitance probe a laboratory calibration." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175802481.
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GARGADENNEC, SYLVAIN. "Determination de coefficient de partage eau/n-octanol de 1,2-dithiole-3-thiones et 1,2-dethiole-3-ones fonctionnalisees." Rennes 1, 1999. http://www.theses.fr/1999REN10160.
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Ce travail est consacre a la determination des coefficients de partage eau n-octanol de 1,2-dithiole-3-thiones et 1,2-dithiole-3-ones fonctionnalisees sur les sommets 4 ou 5 la determination est realisee par appreciation de la concentration du solute en phase aqueuse apres equilibre de partage par c. L. H. P les resultats obtenus sont surprenants et ne peuvent pas etre raisonnablement predits par les methodes de calcul usuelles. En particulier, les 5-formyl ou 5-acyldithiolethiones et dithiolones sont beaucoup plus lipophiles que ne le laissent prevoir les methodes de calcul. Inversement, les esters carboxyliques en 4 des dithiolethiones et dithiolones sont moins lipophiles que prevu. Aucune explication satisfaisante de ces resultats ne peut etre fournie jusqu'a present. Les resultats obtenus demontrent sans aucune ambiguite que les dithiolethiones et dithiolones fonctionnalisees en 4 et en 5 ont une lipophilie tres differente.
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Schmidt, Christian [Verfasser]. "Improved determination of the beta-neutrino angular correlation coefficient a in free neutron decay using the aSPECT experiment / Christian Schmidt." Mainz : Universitätsbibliothek Mainz, 2019. http://d-nb.info/1191284425/34.
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Mabakane, Elizabeth Nontombi. "The determination of distribution coefficient for some elements on the macroporous cation exchanger Amberlyst 15 using nitric acid – methanol mixtures." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2329.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016.The main purpose of this study is to understand the application of ion exchange chromatography on separation of charged ions of elements. Ion exchange chromatography is an analytical method, which is used for the separation of elements, quantitation and qualitation. The use of Amberlyst 15 resin as a source of separation for metal ions has been investigated and studies in various academic disciplines such as chemistry and material science. In this research study, Amberlyst 15 resin was investigated in order to understand the separation of positively charged divalent elements ions (Zn2+, Cu2+, Co2+ and Ni2+). The use of nitric acid and methanol mixture enhanced separation of these metal ions by ensuring that nitric acid is constant and varying methanol concentration. In this study, it was found that the resin has a high affinity for the metal ions at high methanol concentration, hence the distribution coefficient values increase but decreases at low methanol concentrations. The complexities of molecular structure of the salts of the elements provide the more understanding of the metal ion interaction with the resin particle. Furthermore, the role and strength of nitric acid to break the structural bonds and release the metal ions to get sorbed on the resin remains the most essential factor of understanding distribution coefficient values. Method validation parameters such as linearity, precision and accuracy of the method were determined. The method precision and accuracy were determined from the QC samples which is expressed as relative error (%RE) with the total coefficient of variation (%CV’s) were < 20%.
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Atlan, Samuel. "Modelisation de la liberation des composes d'arome a partir de matrices alimentaires dans des systemes experimentaux et en bouche : determination des proprietes et mecanismes de transfert de matiere." Phd thesis, AgroParisTech, 2007. http://pastel.archives-ouvertes.fr/pastel-00003444.
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Les composés d'arôme sont des molécules volatiles présentes à de faibles concentrations dans les aliments. Ils sont responsables de la perception olfactive et constituent un critère déterminant de la qualité organoleptique expliquant les préférences des consommateurs. Afin de mieux comprendre la génération des stimuli lors de la consommation de produits, le travail avait pour objectif l'étude de la libération des composés d'arôme dans les matrices alimentaires réelles, en s'appuyant sur la modélisation des transferts de matière. La démarche mise en oeuvre repose sur : i) l'identification de propriétés des composés d'arôme (coefficients de partage et de diffusion), ii) l'analyse des transferts dans des systèmes in vitro jusqu'à des systèmes in vivo : la bouche consommant l'aliment. Les propriétés physicochimiques sont des données nécessaires aux modèles de transfert de matière. La détermination de ces propriétés a constitué la première partie de ce travail. Les propriétés sont de deux types : les propriétés à l'équilibre entre deux phases (le coefficient de partage) et les propriétés dynamiques (coefficient de diffusion et coefficient de transfert de matière). Un traitement innovant des données expérimentales obtenues par la méthode PRV (Phase Ratio Variation) a été proposé sur 12 molécules de composés d'arômes. Ce traitement permet de déterminer le coefficient de partage (variant entre 3·10-5 et 3·10-2) associé à son intervalle de confiance rigoureusement calculé avec l'ensemble des degrés de liberté disponibles. Concernant la détermination du coefficient de diffusion des composés d'arôme dans les matrices alimentaires complexes, une cellule expérimentale a été spécialement développée. Elle a été initialement conçue en s'appuyant sur la simulation des transferts de matière, puis validée sur des matrices simples. Ensuite, des mesures expérimentales sur des matrices complexes ont été réalisées et ont permis de déterminer le coefficient de diffusion et sa variation suivant la composition de la matrice (nature des protéines) et le procédé (traitement mécanique). L'intervalle de confiance associé à la détermination du coefficient de diffusion a été calculé pour l'hexanoate d'éthyle dans des yaourts de compositions variables en matière grasse et en protéines. Sur un système expérimental simple, nous avons également montré par une analyse des mécanismes de transfert et leur modélisation que le coefficient de partage et le coefficient de diffusion des composés d'arôme pouvaient être déterminés simultanément. Le modèle de libération des composés d'arôme exploité pour l'hexanoate d'éthyle dans des gels de carraghénane a mis en évidence le besoin de connaître et maîtriser les étapes du protocole expérimental. Enfin, un modèle de libération des composés d'arôme lors de la consommation in vivo a été développé. Le modèle prend en compte les propriétés physicochimiques de l'aliment propres aux composés d'arôme et à la matrice, mais également les paramètres physiologiques liés aux sujets. Ce modèle a été établi pour des sujets dits « avaleurs parfaits », qui ferment la cloison entre la bouche et le pharynx lors de la mise en bouche du produit et jusqu'à sa déglutition. Il a permis de simuler la libération des composés d'arôme comme l'hexanoate d'éthyle, le butanoate d'éthyle et l'acétate d'éthyle depuis le produit (yaourt) jusqu'à la cavité nasale des sujets, mais également de déterminer quels sont les paramètres limitants de la libération, notamment le débit respiratoire du sujet.
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Schebywolok, Tomi. "Application of Relative Response Factors in Solid-Phase Micro Extraction GC/MS for the Determination of Polycyclic Aromatic Hydrocarbons in Water." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37860.
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Solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS) is routinely used to analyze polycyclic aromatic hydrocarbons (PAHs) in water. A common SPME-GC/MS approach quantifies target analytes using isotopically labeled standards (IISs); one IIS is needed for each target analyte. This approach is challenging, even prohibitive since IISs are often expensive; moreover, they are generally not available for each analyte of interest. This study developed a novel SPME-GC/MS approach for the quantification of PAHs in water. The new method, which employs only a small number of IISs, uses relative response factor (RRF) (i.e., analyte corresponding to IIS) to quantify PAHs in water. Possible matrix dependency of RRFs values was examined using water that was modified concerning different physical-chemical characteristics (i.e., ionic strength, pH, suspended solids, humic acid, and biological organic carbon represented by hemoglobin). The results revealed that RRFs are not noticeably affected by changing ionic strength and pH; the other three parameters did affect the RRFs. However, the results also showed that the effect is minimal when the solution is dilute (i.e., low concentrations of suspended solids, humic acid or hemoglobin). Relatively stable RRFs for dilute water solutions indicates that this approach can be used for routine quantification of water that does not contain prohibitive amounts of suspended solids, humic acid, and biological organic matter. The developed method was employed to quantify trace levels of PAHs in three different types of water, namely river water, well water, and bottled water. PAH levels in every kind of water were less than 100 ng/L level (i.e., 0.1 ppb). Analyses of spiked water samples containing 2 ng PAHs revealed correlations between calculated RRFs and the physical-chemical properties of the PAHs investigated (i.e., vapor pressure, boiling point, octanol/water partition coefficient, octanol/air partition coefficient, GC retention time). This implies that RRFs for PAHs not examined in this study can be predicted. Overall, the results presented herein constitute a meaningful contribution to the development of SPME-GC/MS methods for quantitative analysis of PAHs and other chemicals in dilute aqueous solutions. Moreover, the development of methods that alleviate the need for IISs corresponding to each target analyte.
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Higa, Carlos Henrique Aguena. "Coeficientes de determinação, predição intrinsicamente multivariada e genética." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-06062007-151732/.
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Esta dissertação de mestrado tem como finalidade descrever o trabalho realizado em uma pesquisa que envolve a análise de expressões gênicas provenientes de microarrays com o objetivo de encontrar genes importantes em um organismo ou em uma determinada doença, como o câncer. Acreditamos que a descoberta desses genes, que chamamos aqui de genes de predição intrinsicamente multivariada (genes IMP), possa levar a descobertas de importantes processos biológicos ainda não conhecidos na literatura. A busca por genes IMP foi realizada em conjunto com estudos de modelos e conceitos matemáticos e estatísticos como redes Booleanas, cadeias de Markov, Coeficiente de Determinação (CoD), Classificação em análise de expressões gênicas e métodos de estimação de erro. No modelo de redes Booleanas, introduzido na Biologia por Kauffman, as expressões gênicas são quantizadas em apenas dois níveis: \"ligado\'\' ou \"desligado\'\'. O nível de expressão (estado) de cada gene, está relacionado com o estado de alguns outros genes através de uma função lógica. Adicionando uma perturbação aleatória a este modelo, temos um modelo mais geral conhecido como redes Booleanas com perturbação. O sistema dinâmico representado pela rede é uma cadeia de Markov ergódica e existe então uma distribuição de probabilidade estacionária. Temos a hipótese de que os experimentos de microarray seguem esta distribuição estacionária. O CoD é uma medida normalizada de quanto a expressão de um gene alvo pode ser melhor predita observando-se a expressão de um conjunto de genes preditores. Uma determinada configuração de CoDs caracteriza um gene alvo como sendo um gene IMP. Podemos trabalhar não somente com genes alvo, mas também com fenótipos alvo, onde o fenótipo de um sistema biológico poderia ser representado por uma variável aleatória binária. Por exemplo, podemos estar interessados em saber quais genes estão relacionados ao fenótipo de vida/morte de uma célula. Como a distribuição de probabilidade das amostras de microarray é desconhecida, o estudo dos CoDs é feito através de estimativas. Entre os métodos de estimação de erro estudados para este propósito podemos citar: Holdout, Resubstituição, Cross-validation, Bootstrap e .632 Bootstrap. Os métodos foram implementados para calcular os CoDs, permitindo então a busca por genes IMP. Os programas implementados na pesquisa foram usados em conjunto com uma pesquisa realizada pelo Prof. Dr. Hugo A. Armelin do Instituto de Química da USP. Este estudo em particular envolve a busca de genes importantes relacionados à morte de células tumorigênicas de camundongo disparada por FGF2 (Fibroblast Growth Factor 2). Nesta pesquisa observamos sub-redes de genes envolvidos no processo biológico em questão e também encontramos genes que podem estar relacionados ao fenômeno de morte das células de camundongo ou que estão, de fato, participando de alguma via disparada pelo FGF2. Esta abordagem de análise de expressões gênicas, juntamente com a pesquisa realizada pelo Prof. Armelin, resulta em uma metodologia para buscas de genes envolvidos em novos mecanismos de células tumorigênicas, ativados pelo FGF2. Na realidade esta metodologia pode ser aplicada em qualquer processo biológico de interesse científico, desde que seja possível modelar o problema proposto no contexto de redes Booleanas, coeficientes de determinação e genes IMP.This Master\'s degree dissertation describes a research that involves an analysis of gene expression data from microarray experiments with the purpose to find important genes in certain organisms or diseases such as cancer. We believe that these type of genes, called intrinsically multivariately predictive genes (IMP genes), can lead to the discovery of important biological process that are unknown in the literature. The search for IMP genes was done with the study of mathematical and statistical models such as Boolean Networks, Markov Chains, Coefficient of Determination (CoD), Classification and Error Estimation Methods. In the Boolean network model, introduced in Biology by Kauffman, the gene expression is quantized in only two levels: ON and OFF. The expression level (state) of each gene is related with the state of some other genes through a logical function. Adding a random perturbation to this model, we have a more general Boolean-type model called Boolean network with perturbation. The dynamical system represented by this network is an ergodic Markov chain and thereby it possesses a steady-state distribution. We have the hypothesis that the microarray experiments follow this steady-state distribution. The CoD is a normalized measure of how much a gene expression of a target gene can be better predicted observing the expression of a set of predictor genes. A certain configuration of CoDs characterizes a target gene as an IMP gene. We can deal not only with target genes, but also with target phenotypes, where the phenotype of a biological system could be represented by a binary random variable. For example, we could be interested in knowing which genes are related to a life/death cell phenotype. Since the joint probability distribution of the gene expressions is unknown, the CoDs must be computed through estimated values. Among the error estimation methods studied we can cite: Holdout, Resubstitution, Cross-validation, Bootstrap and .632 Bootstrap. Those methods were implemented as a software in order to compute the CoDs and thereby allowing us to search for IMP genes. The software we implemented in this research was used within a research developed by Professor Dr. Hugo A. Armelin from the Instituto de Química - University of Sao Paulo. This particular research involves the search for important genes related to the death of tumorigenic mouse cells triggered by FGF2 (Fibroblast Growth Factor 2). From this research cooperation, we built some gene subnetworks involved in the target biological process and we found some genes that could be related to the death phenotype of mouse cells. This approach of gene expression analysis, together with the research developed by Professor Armelin, results in a methodology to search for important genes that could be involved in new mechanisms of tumorigenic cells triggered by FGF2. Actually, this methodology can be applied to any biological process of scientific interest, if one can model the proposed problem in the context of Boolean Networks, Coefficient of Determination and IMP genes.
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Rio, Simon. "Contributions to genomic selection and association mapping in structured and admixed populations : application to maize." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS097.
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L'essor des marqueurs moléculaires (SNPs) a révolutionné les méthodes de génétique quantitative en permettant l'identification de régions impliquées dans le déterminisme génétique des caractères (QTLs) via la génétique d'association (GWAS), ou encore la prédiction des performances d'individus sur la base de leur information génomique (GS). La stratification des populations en groupes génétiques est courante en sélection animale et végétale. Cette structure peut impacter les méthodes de GWAS et de GS via des différences de fréquence et d'effets des allèles des QTL, ainsi que par des différences de déséquilibre de liaison (LD) entre SNP et QTL selon les groupes.Pendant cette thèse, deux panels de diversité de maïs ont été utilisés, présentant des niveaux différents de structuration: le panel “Amaizing Dent” représentant les lignées dentées utilisées en Europe et le panel “Flint-Dent” incluant des lignées dentées, cornées européennes, ainsi que des lignées admixées entre ces deux groupes.En GS, l'impact de la structure génétique sur la qualité des prédictions a été évalué au sein du premier panel pour des caractères de productivité et de phénologie. Cette étude a mis en évidence l'intérêt d'une population d'entraînement (TS) dont la constitution en matière de groupes génétiques est similaire à celle de la population à prédire. Assembler les différents groupes au sein d'un TS multi-groupe apparaît comme une solution efficace pour prédire un large spectre de diversité génétique. Des indicateurs a priori de la précision des prédictions génomiques, basés sur le coefficient de détermination, ont également été évalués, mettant en évidence une efficacité variable selon le groupe et le caractère étudié.Une nouvelle méthodologie GWAS a ensuite été développée pour étudier l'hétérogénéité des effets capturés par les SNPs selon les groupes. L'intégration des individus admixés à l'analyse permet de séparer les effets des facteurs responsables de l'hétérogénéité des effets alléliques: différence génomique locale (liée au LD ou à une mutation spécifique d'un groupe) ou interactions épistatiques entre le QTL et le fonds génétique. Cette méthodologie a été appliquée au panel “Flint-Dent” pour la précocité de floraison. Des QTL ont été détéctés comme présentant des effets groupe-spécifiques interagissant ou non avec le fonds génétique. De nombreux QTL présentant un profil original ont pu être mis en évidence, incluant des locus connus tels que Vgt1, Vgt2 ou Vgt3. Une importante épistasie directionnelle a aussi été mise en évidence grâce aux individus admixés, confortant l'existence d'interactions épistatiques avec le fonds génétique pour ce caractère.Sachant l'existence de cette hétérogénéité d’effets alléliques, nous avons développé deux modèles de prédictions génomiques nommées Multi-group Admixed GBLUP (MAGBLUP). Ceux-ci modélisent des effets groupe-spécifiques aux QTLs et sont adaptés à la prédiction d'individus admixés. Le premier permet d'identifier la variance génétique additionnelle créée par l'admixture (variance de ségrégation), alors que le second permet d'évaluer le degré de conservation des effets alléliques entre groupes. Ces deux modèles ont montré un intérêt certain par rapport à des modèles standards pour prédire des caractères simulés, mais plus limité sur des caractères réels.Enfin, l'intérêt des individus admixés dans la constitution de TS multi-groupes a été évalué à l'aide du second panel. Si leur intérêt a clairement été mis en évidence pour des caractères simulés, des résultats plus variables ont été observés avec les caractères réels, pouvant s'expliquer par la présence d'interactions avec le fonds génétique.Les nouvelles méthodes et l'utilisation d'individus admixés ouvrent des pistes de recherches intéressantes pour les études de génétique quantitative en population structuréeThe advent of molecular markers (SNPs) has revolutionized quantitative genetics methods by enabling the identification of regions involved in the genetic determinism of traits (QTLs) thanks to association studies (GWAS), or the prediction of the performance of individuals using genomic information (GS). The stratification of populations into genetic groups is common in animal and plant breeding. This structure can impact GWAS and GS methods through group differences in QTL allele frequencies and effects, as well as in linkage disequilibrium (LD) between SNP and QTL.During this thesis, two maize diversity panels were used, presenting different levels of structuration: the "Amaizing Dent" panel representing the diversity of dent lines used in Europe and the "Flint-Dent" panel including dent, flint and admixed lines between these two groups.In GS, the impact of genetic structure on genomic prediction accuracy was evaluated in the first panel for productivity and phenology traits. This study highlighted the interest of a training population (TS) whose constitution in terms of genetic groups is similar to that of the population to be predicted. Assembling the different groups within a multi-group TS appears as an effective solution to predict a broad spectrum of genetic diversity. A priori indicators of genomic prediction accuracy, based on the coefficient of determination, were also evaluated and highlighted a variable efficiency depending on the group and the trait.A new GWAS methodology was then developed to study the heterogeneity of the allele effects captured by SNPs depending on the group. The integration of admixed individuals to such analyses allows to disentangle the factors causing the heterogeneity of allele effects across groups: local genomic difference (related to LD or group-specific mutation) or epistatic interactions between the QTL and the genetic background. This methodology was applied to the "Flint-Dent" panel for flowering time. QTLs have been detected as presenting group-specific effects interacting or not with the genetic background. QTLs with an original profile have been highlighted, including known loci such as Vgt1, Vgt2 or Vgt3. Significant directional epistasis has also been demonstrated using admixed individuals and supported the existence of epistatic interactions with the genetic background for this trait.Based on the existence of such heterogeneity of allele effects, we have developed two genomic prediction models named Multi-group Admixed GBLUP (MAGBLUP). Both model group-specific QTL effects and are suited to the prediction of admixed individuals. The first allows the identification the additional genetic variance created by the admixture (segregation variance), while the second allows the evaluations of the degree of conservation of SNP allele effects across groups. These two models showed a certain interest compared to standard models to predict simulated traits, but it was more limited on real traits.Finally, the interest of admixed individuals in multi-group TS was evaluated using the second panel. Although their interest has been clearly demonstrated for simulated traits, more variable results have been observed with the real traits, which can be explained by the presence of interactions with the genetic background.The new methods and the use of admixed individuals open interesting lines of research for quantitative genetics studies in structured population
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Sirtautas, Danius. "Lietuvos geriamojo vandens suvartojimo ir jo pokyčių įvertinimas didžiuosiuose miestuose." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140617_121453-23208.
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Magistrantūros studijų baigiamajame darbe nagrinėjamos geriamojo vandens suvartojimo ir jo pokyčių tendencijos 1996–2012 m. laikotarpyje. Tyrimo objektu pasirinkti didieji Lietuvos miestai – Vilnius, Kaunas, Klaipėda.
Tyrimo tikslas – išanalizuoti statistikos departamento duomenis apie vandens suvartojimą ir jo pokyčių tendencijas bei atlikti įvairių veiksnių, lemiančių vandens suvartojimą, analizę.
Šiame darbe analizuojami veiksniai, kurie galėtų daryti įtaką išgaunamo ir sunaudojamo požeminio vandens kiekiui. Šie veiksniai gali būti įvardijami kaip – gyventojų skaičiaus mažėjimas, vandens tiekimo ir nuotekų surinkimo kainos, sumažėjusi pramonės gamyba, BVP kitimas, elektros kainos, būsto vartojimo išlaidos. Požeminio vandens gavyba nuo 1996 m. iki 2012 m. sumažėjo 45 %, todėl galima teigti, kad suprojektuotos vandenvietes ir vandentiekio tinklai dirba sumažintu pajėgumu, kas gali bloginti vandens kokybę dėl užsistovinčio vandens vamzdžiuose.
Analizuojant statistikos departamento duomenis buvo ieškomas ryšys tarp suvartoto vandens kiekio ir gyventojų skaičiaus kitimo, elektros kainos, pinigų skiriamų būsto vartojimo išlaidoms vienam asmeniu bei BVP kitimo. Remiantis duomenimis paaiškėjo, kad laikotarpyje nuo 1996 m. iki 2012 m. Lietuvoje vienas žmogus per parą suvartojo apie 106 l vandens. Analizuojant statistinį ryšį tarp vandens suvartojimo ir pinigų sumos skiriamos vartojimo išlaidoms, Kaune, gautas aukštas determinacijos koeficientas R2=0,79, Vilniuje – 0,86, Klaipėdoje... [toliau žr. visą tekstą]The tendencies of changes in water consumption are discussed in this final master’s studies research in 1996–2012 time periods. As research objects are chosen large Lithuanian cities - Vilnius, Kaunas, Klaipėda. The aim of research is to collect and analyze data on water consumption as well as the changes in trends and perform analysis of factors influencing water consumption. This research shows the factors that could affect the extracted and consumed amount of underground water. These factors can be identified as population, GDP changes, housing consumption expenditure. Groundwater extraction from 1996 to 2012 decreased by 45%, suggesting that the designed water supplies and water-supply system operates at a reduced capacity, which can lead to deterioration in water quality due to standing water in pipes. The analysis of the statistical data of the Department has been requested for the relationship between water consumption and population changes, electricity prices, the money allocated for housing consumption expenditure per capita and GDP changes. The statistical data showed that during the period from 1996 to 2012 one person consumed on average 106 liters of water per day in Lithuania. The analysis of the statistical relationship between the rate of water consumption and the amount of money allocated to consumer spending in Kaunas received a high coefficient of determination R2 = 0.79, Vilnius – 0,86, in Klaipėda much lower – 0,45.
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Kocsisová, Tereza. "Zdanění a doprava." Master's thesis, Vysoká škola ekonomická v Praze, 2016. http://www.nusl.cz/ntk/nusl-262359.
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The aim of this diploma thesis is to find suitable regression models between the chosen statistical data of transport and GDP per capita and determine whether these models are statistically significant. The first part is a theoretical introduction to the problems of transport in terms of economics, as well as a description of methods of regression analysis, which is used in the practical part. The practical part draws data from Eurostat's website that provide for this thesis sufficient statistical basis. The data are graphically processed as scatter charts, based on these are determined mathematical equation of regression. The choice of suitable regression analysis is based on coefficient of determination and significance level is alpha = 0,05.
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Khodayari, Mehdi [Verfasser]. "Fuel Cells, Metal/Air Batteries : characterization of dual thin-layer flow through cell and determination of solubility and diffusion coefficient of oxygen in aqueous and non-aqueous electrolytes / Mehdi Khodayari." Bonn : Universitäts- und Landesbibliothek Bonn, 2015. http://d-nb.info/1077290101/34.
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Cousin-Lucasseau, Catherine. "Absorption i. R. Du co::(2) dans la fenetre atmospherique autour de 2400 cm : determination de la dependance en temperature du coefficient d'absorption,influence des interferences spectrales sur le profil observe." Rennes 1, 1987. http://www.theses.fr/1987REN10032.
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Etude systematique en temperature (190-300 k) du coefficient d'absorption pour co::(2)-co::(2), co::(2)-n::(2) et co::(2)-o::(2) dans les microfenetres entre les raies, r a j eleve et au-dela de la tete de bande. Analyse theorique du comportement sublorentzien de l'absorption dans la zone des microfenetres. (utilisation de la theorie de l'impact)
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Tegze, Ondřej. "Vytvoření cenových podkladů pro stanovení tržního nájemného v bytech pro lokalitu Brno - Žabovřesky." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-232534.
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The aim of my diploma thesis is to prepare documents for price calculation and determination of the common rent in the suburb of Brno - Žabovřesky. In this work, I used information from executed leases Realtors Matras&Matras & Real Estate Ltd. and Dvorak. Analysis of factors affecting price formation I have devoted the factors that I considered at that locality as valid for determining the price and verifying their influence on rental prices. I added my own factor into the monitored critical factors. This factor is noise. As the analysis results showed it was a major factor that significantly affects the final price of the lease. His inclusion among the decisive factors was correct. By setting standards and calculation of coefficients, I obtain results that helped determine the normal cost of rent and contributed to the view of the importance of determining the level of the individual factors to calculate the final rental price. Data collection, analysis and examination of the relationships between the key factors, I see as a guide for calculating the normal price, which will be used by districts and the real estate market.
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Moracz, Kelle. "Comprehension and Interpretation of Common Language Effect Size Displays." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573756511230833.
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Jansa, Jakub. "Stochastická předpověď průměrných měsíčních průtoku ve vybraném vodoměrném profilu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240072.
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The diploma thesis is focused on the average monthly flows forecast in the selected hydrometric profile. Aim of this work will be evaluation of the calculated values and the interpretation of the results in understandable form. The next step will be find an appropriate connection between randomly-generated inputs in the form of random real flow series using the standard hydrological prediction models. This models are based on the principles of artificial intelligence and probability model. The result of the work will be verification of procedures and compilation of mean monthly flow stochastic forecast in selected hydrometric profile, which would be used for a reservoirs management, respectively for water systems management.
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Lima, Leandro de Araujo. "Um algoritmo eficiente para o crescimento de redes sobre o grafo probabilístico completo do sistema de regulação gênica considerado." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-22012010-120624/.
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Sabe-se biologicamente que o nível de expressão dos genes está entre os fatores podem indicar o quanto estes estão em atividade em determinado momento. Avanços na tecnologia de microarray têm possibilitado medir os níveis de expressão de milhares de genes ao mesmo tempo. Esses dados podem ser medidos de maneira a formarem uma série temporal, que pode ser tratada estatisticamente para serem obtidas informações sobre as relações entre os genes. Já foram propostos vários modelos para tratar redes gênicas matematicamente. Esses modelos têm evoluído de forma a agregarem cada vez mais características das redes reais. Neste trabalho, será feita uma revisão de modelos discretos para redes de regulação gênica, primeiramente com as redes Booleanas, modelo determinístico, e depois as redes Booleanas probabilísticas e as redes genéticas probabilísticas, modelos que tratam o problema estocasticamente. Usando o último modelo citado, serão mostrados dois métodos para estimar o nível de predição entre os genes, coeficiente de determinação e informação mútua. Além de se estimar essas relações, foram desenvolvidas algumas técnicas para construir redes a partir de genes específicos, que são chamados sementes. Também serão apresentados dois desses métodos de crescimento de redes e, baseado neles, um terceiro método que foi desenvolvido neste trabalho. Foi criado um algoritmo que realiza o crescimento da rede mudando as sementes a cada iteração, agrupando estes genes em grupos com diferentes níveis de confiança, chamados camadas. O algoritmo também usa outros critérios para agregar novos genes à rede. Após a explanação desses métodos, será mostrado um software que, a partir de dados temporais de expressão gênica, estima as dependências entre os genes e executa o crescimento da rede em torno de genes que se deseje estudar. Também serão mostradas as melhorias feitas no programa. Ao final, serão apresentados alguns testes feitos com dados do Plasmodium falciparum, parasita causador da malária.It\'s known that gene expression levels are among the factors that can show how genes are active in certain moment. Advances in microarray technology have given the possibility to measure expression levels of thousands of genes in a certain instant of time. These data constitute time series that we can treat statistically in order to get information genes relationships. Many models were proposed to treat gene networks mathematically. These models have evolved to aggregate more and more real networks features. In this work, it is made a brief review of discrete models of regulatory genetic networks, initially Boolean networks, a deterministic model, and then probabilistic Boolean networks and probabilistic genetic networks, models that treat the problem stochastically. Using the last model cited, two methods to estimate the prediction level among genes are shown, coefficient of determination and mutual information. Besides estimating these relations, some techniques have been developed to construct networks from specific genes, that are called seeds. It will be also shown two methods of network growth and, based on these, a third method that was developed during this work. An algorithm was created, such that it grows the network changing the seeds in each iteration, grouping these genes in groups with different level of confidence, called layers. The algorithm also uses other criteria to add new genes to the network. After studying these methods, it will be shown a software that, using time series gene expression data, estimates dependences among genes and runs the network growing process around chosen genes. It is also presented the improvements made in the program. Finally, some tests using data of Plasmodium falciparum, malaria parasite, are shown.
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Khalfalla, Hamza Abdulmagid. "Modelling and optimisation of oxidative desulphurization process for model sulphur compounds and heavy gas oil : determination of rate of reaction and partition coefficient via pilot plant experiment : modelling of oxidation and solvent extraction processes : heat integration of oxidation process : economic evaluation of the total process." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4247.
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Heightened concerns for cleaner air and increasingly more stringent regulations on sulphur content in transportation fuels will make desulphurization more and more important. The sulphur problem is becoming more serious in general, particularly for diesel fuels as the regulated sulphur content is getting an order of magnitude lower, while the sulphur contents of crude oils are becoming higher. This thesis aimed to develop a desulphurisation process (based on oxidation followed by extraction) with high efficiency, selectivity and minimum energy consumption leading to minimum environmental impact via laboratory batch experiments, mathematical modelling and optimisation. Deep desulphurization of model sulphur compounds (di-n-butyl sulphide, dimethyl sulfoxide and dibenzothiophene) and heavy gas oils (HGO) derived from Libyan crude oil were conducted. A series of batch experiments were carried out using a small reactor operating at various temperatures (40-100 °C) with hydrogen peroxide (H2O2) as oxidant and formic acid (HCOOH) as catalyst. Kinetic models for the oxidation process are then developed based on 'total sulphur approach'. Extraction of unoxidised and oxidised gas oils was also investigated using methanol, dimethylformamide (DMF) and N-methyl pyrolidone (NMP) as solvents. For each solvent, the 'measures' such as: the partition coefficient (KP), effectiveness factor (Kf) and extractor factor (Ef) are used to select the best/effective solvent and to find the effective heavy gas oil/solvent ratios. A CSTR model is then developed for the process for evaluating viability of the large scale operation. It is noted that while the energy consumption and recovery issues could be ignored for batch experiments these could not be ignored for large scale operation. Large amount of heating is necessary even to carry out the reaction at 30-40 °C, the recovery of which is very important for maximising the profitability of operation and also to minimise environmental impact by reducing net CO2 release. Here the heat integration of the oxidation process is considered to recover most of the external energy input. However, this leads to putting a number of heat exchangers in the oxidation process requiring capital investment. Optimisation problem is formulated using gPROMS modelling tool to optimise some of the design and operating parameters (such as reaction temperature, residence time and splitter ratio) of integrated process while minimising an objective function which is a coupled function of capital and operating costs involving design and operating parameters. Two cases are studied: where (i) HGO and catalyst are fed as one feed stream and (ii) HGO and catalyst are treated as two feed streams. A liquid-liquid extraction model is then developed for the extraction of sulphur compounds from the oxidised heavy gas oil. With the experimentally determined KP multi stage liquid-liquid extraction process is modelled using gPROMS software and the process is simulated for three different solvents at different oil/solvent ratios to select the best solvent, and to obtain the best heavy gas oil to solvent ratio and number of extraction stages to reduce the sulphur content to less than 10 ppm. Finally, an integrated oxidation and extraction steps of ODS process is developed based on the batch experiments and modelling. The recovery of oxidant, catalyst and solvent are considered and preliminary economic analysis for the integrated ODS process is presented.
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Arenson, Mordechai. "Determination of convective heat transfer coefficients in turning." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37256.pdf.
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Huntul, Mousa Jaar M. "Determination of unknown coefficients in the heat equation." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22491/.
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The purpose of this thesis is to find the numerical solutions of one or multiple unknown coefficient identification problems in the governing heat transfer parabolic equations. These inverse problems are numerically solved subject to various types of overdetermination conditions such as the heat flux, nonlocal observation, mass/energy specification, additional temperature measurement, Cauchy data, general integral type over-determination, Stefan condition and heat momentum of the first, second and third order. The main difficulty associated with solving these inverse problems is that they are ill-posed since small changes in the input data can result in enormous changes in the output solution, therefore traditional techniques fail to provide accurate and stable solutions. Throughout this thesis, the finite-difference method (FDM) with the Crank-Nicolson (C-N) scheme is mainly used as a direct solver except in Chapters 8 and 9 where an alternating direction explicit (ADE) method is employed in order to deal with the two-dimensional heat equation. An explicit forward time central space (FTCS) method is also employed in Chapter 2 for the extension to higher dimensions. The treatment for solving a degenerate parabolic equation, which vanishes at the initial moment of time is discussed in Chapter 6. The inverse problems investigated are discretised using FDM or ADE and recast as nonlinear least-squares minimization problems with lower and upper simple bounds on the unknown coefficients. The resulting optimization problems are numerically solved using the \emph{lsqnonlin} routine from MATLAB optimization toolbox. The stability of the numerical solutions is investigated by introducing random noise into the input data which yields unstable results if no regularization is employed. The regularization method is included (where necessary) in order to reduce the influence of measurement errors on the numerical results. The choice of the regularization parameter(s) is based on the L-curve method, on the discrepancy principle criterion or on trial and error.
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Nadji, Séverin Landry. "Développement de systèmes de contrôle in situ des propriétés optiques de filtres interférentiels." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0155.
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La réalisation de fonctions de filtrage complexes nécessite une parfaite maîtrise du processus de dépôt ainsi qu’un contrôle précis et en temps réel de l’épaisseur optique des couches déposées. Au cours de ma thèse, consacrée au développement de nouvelles modalités de contrôle optique in situ, je me suis particulièrement intéressé à deux sujets différents, à savoir : - D’une part, la détermination de la dépendance spectrale des constantes optiques (indice de réfraction et coefficient d’extinction) de matériaux diélectriques. Un moyen possible pour effectuer cette détermination consiste à utiliser un système de contrôle optique large bande afin d’enregistrer les spectres de transmission de l’empilement au fur et à mesure de sa formation. En effet, l’évolution temporelle, à chaque longueur d’onde, de ces spectres de transmission contient des informations quantitatives liées aux constantes optiques que nous souhaitons déterminer. - D’autre part, la mesure en temps réel du coefficient de réflexion (r) d’un empilement, en amplitude et en phase, lors de son dépôt. En effet, les méthodes de contrôles optiques en intensité présentent des limitations que la connaissance de l’information de phase devrait permettre de contourner. Cette mesure est réalisée par interférométrie holographique digitale à faible cohérence sur un substrat éclairé par sa face arrière et dont la face avant est équipée d’un masque annulaire. Ceci donne accès aux information de phase et d’amplitude recherchées tout en s’affranchissant des vibrations générées par le fonctionnement de la machine de dépôt ainsi que du mouvement de rotation à 120 tours par minute qu’effectue le porte-substratThe realization of complex filtering functions requires a perfect mastering of the deposition process as well as an accurate real time monitoring of the optical thickness of the deposited layers. During my PhD thesis, devoted to the development of new methods of in situ optical monitoring, I was particularly interested in two different subjects, namely:- On the one hand, the determination of the spectral dependence of optical constants (refractive index and extinction coefficient) of dielectric materials. A possible way to achieve this determination consist in using a broadband optical monitoring system in order to record the transmission spectra, in real time, of the stack during its formation. Indeed, the temporal evolution, at each wavelength, of these transmission spectra provide quantitative information related to the optical constants that we wish to determine.- On the other hand, the real time measurement of the reflection coefficient (r) of a stack, in amplitude and phase, during its deposition. Indeed, the optical monitoring methods based on intensity proprieties present some limitations that the knowledge of phase information should overcome. This measurement is performed by low coherence digital holographic interferometry on a substrate illuminated by its rear face and whose front face is equipped with an annular mask. This gives access to desired phase and amplitude information while avoiding the parasitic influence of the substrate motions induced by the vibrations of the deposition machine, and the rotation of the substrate holder at 120 rounds per minute
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Guimarães, Paulo Henrique Ramos. "Parâmetros genéticos e fenotípicos em arroz irrigado estimados por método de análise espacial." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/3956.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Some spatial analysis methods have been applied in order to mitigate environmental variation. The objective of this study was to evaluate the efficiency of spatial statistical, through the method of Papadakis, relative to the analysis to augmented blocks Federer in the correction of environmental variation. Were evaluated 198 progenies S0:2 of rice and four witnesses for augmented blocks of Federer. Data set were taken in the grain yield (GY, kg ha- 1) and plant height (PH, cm). The data set were subjected to variance analyses and were estimated the genetic and phenotypic parameters. The different approaches (BAF and Papadakis) were compared as to their estimates of genetic and phenotypic parameters. The ranking of adjusted means in the two models analyzed was performed, and calculated the Spearman correlation. There have been improvements in the statistics that depict the experimental accuracy when the spatial analysis was, that affect the estimates of genetic and phenotypic parameters. The use of the Papadakis method yielded fewer iterations compared to BAF for the same value of . Was able to gain direct selection for the AP and PG characters when the Papadakis method was used. With the use of spatial analysis selection was less influenced by the effect of environmental variation. Finally it was found that the spatial analysis methods were effective in the removal of environmental effects highlighting the Papadakis method, indicating that it can provide improvement
Alguns métodos de análise espacial têm sido aplicados objetivando reduzir a variação ambiental. O objetivo deste trabalho foi avaliar a eficiência da análise espacial, por meio do método de Papadakis, em relação ao delineamento de blocos aumentados de Federer na correção da variação ambiental. Foram avaliadas 198 progênies S0:2 de arroz irrigado e quatro testemunhas no delineamento de blocos aumentados de Federer. Os caracteres avaliados foram: produção de grãos (PG, kg ha-1) e de altura de plantas (AP, cm). Foi efetuada análise de variância para os caracteres estudados e estimados os componentes de variância e os parâmetros genéticos e fenotípicos. As diferentes abordagens (BAF e Papadakis) foram comparadas quanto às suas estimativas de parâmetros genéticos e fenotípicos e correlação de Spearman. Houve melhorias nas estatísticas que retratam a precisão experimental quando a análise espacial foi utilizada, isto influenciou as estimativas de parâmetros genéticos e fenótipos. O uso do método de Papadakis apresentou a necessidade de uso de menor número de repetições em relação ao BAF para o mesmo valor de . Houve ganho de seleção direto para os caracteres AP e PG quando o método de Papadakis foi utilizado. Com o uso da análise espacial a seleção foi menos influenciada pelo efeito da variação ambiental. Por fim verificou-se que o método de Papadakis foi eficiente na remoção dos efeitos ambientais, indicando que o mesmo pode proporcionar melhoria na precisão experimental, o que torna o processo seletivo mais eficiente.
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Yamana, Shunsuke. "Determination of holomorphic modular forms by primitive Fourier coefficients." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/124481.
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Miralha, Lorrayne. "ACCOUNTING FOR SPATIAL AUTOCORRELATION IN MODELING THE DISTRIBUTION OF WATER QUALITY VARIABLES." UKnowledge, 2018. https://uknowledge.uky.edu/geography_etds/55.
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Several studies in hydrology have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this thesis, I hypothesized that SAC, inherently possessed by a response variable, influences spatial modeling outcomes. I selected ten watersheds in the USA and analyzed them to determine whether water quality variables with higher Moran’s I values undergo greater increases in the coefficient of determination (R²) and greater decreases in residual SAC (rSAC) after spatial modeling. I compared non-spatial ordinary least squares to two spatial regression approaches, namely, spatial lag and error models. The predictors were the principal components of topographic, land cover, and soil group variables. The results revealed that water quality variables with higher inherent SAC showed more substantial increases in R² and decreases in rSAC after performing spatial regressions. In this study, I found a generally linear relationship between the spatial model outcomes (R² and rSAC) and the degree of SAC in each water quality variable. I suggest that the inherent level of SAC in response variables can predict improvements in models before spatial regression is performed. The benefits of this study go beyond modeling selection and performance, it has the potential to uncover hydrologic connectivity patterns that can serve as insights to water quality managers and policy makers.
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Zoller, Alexander. "Development and kinetic modeling of resins for advanced thermoplastic polymer composite materials." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4728.
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L’objectif de cette thèse est de développer un matériau à base de polyméthacrylate de méthyle (PMMA) amorcé par une réaction redox à température ambiante pour produire des composites thermoplastiques. Plus particulièrement, notre travail a consisté à étudier le mécanisme d’amorçage afin d’améliorer la formulation de la résine en terme de cinétique de polymérisation. Afin d’atteindre cet objectif, les paramètres d’Arrhenius de la décomposition d’amorceur ont été déterminés et intégrés dans un modèle de simulation numérique décrivant la polymérisation du MMA à température ambiante développé à l’aide du logiciel PREDICI. Basé sur cette simulation, des différents paramètres ont été testés dans le but de diminuer le temps de polymérisation. En complément de la détermination des paramètres du système d’amorçage, une étude de copolymérisation avec un grand nombre de comonomères a été effectuée. Cette étude a conduit à l’identification d’un monomère permettant d’accélérer la vitesse de polymérisation : le méthacrylate d’acetoacetoxyethyle (AAEMA). Une étude cinétique de ce monomère a été réalisée avec l’identification du coefficient de la vitesse de propagation kp ainsi que les paramètres de copolymérisation avec MMA, rMMA et rAAEMA. Les paramètres cinétiques, qui ont été déterminés expérimentalement, ont été vérifiés par une simulation numérique de copolymérisation de MMA et AAEMAComposite materials are used for decades as high-performance materials in industry. Up to date these materials were based on non-recyclable thermoset polymers. Nowadays, environmental and economical restrictions enhance the development of recyclable composite materials. For answering that demand, research focuses on the development of recyclable thermoplastic polymer composites. Within this context, the work of this thesis focuses on the development of a material based on a poly(methyl methacrylate) (PMMA) resin initiated with a redox initiation system at room temperature in order to prepare thermoplastic composites. More precisely, our work consisted of studying this initiation system and to improve the kinetics of the resin formulation. For that purpose, the Arrhenius parameters of the initiator decomposition reaction were determined and implemented in a simulation model that describes the polymerization of MMA at room temperature. Based on the simulation carried out on the software PREDICI, several conditions were tested aiming in the decrease of the polymerization times. Besides investigating parameters concerning the initiation system, a copolymerization study, using a large variety of comonomers, was conducted. This study led to the identification of an interesting fast polymerizing methacrylate: acetoacetoxyethyl methacrylate (AAEMA). The kinetics of this monomer were studied including the determination of the propagation rate coefficient kp and the copolymerization parameters with MMA rMMA and rAAEMA. The determined kinetic parameters were finally verified by a copolymerization simulation of MMA and AAEMA
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Laufer, Jan. "Photothermal determination of optical coefficients using an optical fibre sensor." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394370.
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Sawicki, Jerezy Teodor. "Experimental and theoretical determination of hydrostatic/hybrid journal bearing rotordynamic coefficients." Case Western Reserve University School of Graduate Studies / OhioLINK, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1056560686.
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Loginov, Maksym. "Preparation of concentrated mineral and bio-suspensions by filtration with alternative pretreatments and determination of permeability and rheological properties of obtained particulate systems." Compiègne, 2011. http://www.theses.fr/2011COMP1933.
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Ce travail de thèse est axé sur l'effet de différentes méthodes de prétraitement (utilisation des dispersants, traitement électrique et homogénéisation à haute pression) sur la filtration des suspensions minérales (kaolin, carbonate de calcium) et biologiques (levure). Il traite également de la détermination des propriétés locales de compression-perméabilité de suspensions concentrées à partir d'essais de sédimentation centrifuge. Une étude est menée sur l'influence de dispersants pour la préparation de suspensions de kaolin concentrées mais demeurant fluide. L'augmentation de la concentration de la suspension provoque une percolation des particules de kaolin stabilisées et une diminution brusque de la fluidité. Cependant, à partir d'une concentration massique de la suspension de 70 %, son caractère fluide devient faible. Cela s'explique par la morphologie des particules de kaolin (haut rapport hauteur/ largeur). Une suspension de carbonate de calcium très concentrée (> 75 % massique) et fluide peut être préparée par filtration dynamique et addition d'un dispersant : le polyacrylate de sodium. L'étape à laquelle est introduit le polyacrylate de sodium influence la concentration de la suspension. Ainsi, l'ajout du dispersant au cours de la filtration permet d'atteindre une siccité optimale supérieure à celle obtenue si la suspension est défloculée par le dispersant avant filtration. Une étude porte sur le traitement en continu des suspensions de levures par décharges électriques de haute tension (DEHT). Il est constaté que ce procédé peut être utilisé pour la destruction des cellules et l'extraction des bioproduits intracellulaires. Cependant, il provoque aussi une formation de débris cellulaires et une diminution du taux de filtration due au colmatage des membranes. La comparaison de la nouvelle méthode de DEHT avec celle classique d'homogénéisation à haute pression (HHP) met en évidence que le traitement par HHP est une méthode de destruction plus efficace que le DEHT. Ainsi, pour une même valeur de l'indice de désintégration des cellules de levure (Z), il permet une extraction supérieure des protéines et des autres bioproduits. Pourtant, si la valeur de l'indice de désintégration dépasse 0,9, la filtration de la suspension traitée par HHP est régie par un mécanisme de colmatage des pores, entraînant un très faible taux de filtration. Enfin, deux méthodes indépendantes d'analyse des dépendances expérimentales obtenues durant la consolidation centrifuge sont développées. Les dépendances des caractéristiques locales de compression et de perméabilité en fonction de la pression de phase solide ont été estimées par ces méthodes pour la suspension aqueuse de carbonate de calciumFiltration is a mechanical operation used for solid-liquid separation. It is widely employed for preparation of concentrated mineral suspensions and for purification of biological suspensions. The efficiency of filtration is mainly determined by filtration rate, which depends on colloidal properties of initial suspension (size of particles and aggregation state). In order to improve filtration efficiency, initial suspensions are usually pretreated by flocculants. Flocculation decreases concentration of fine particles, enhances aggregation of particles, decreases specific cake resistance, and thus increases filtration rate. However, use of flocculants may also deteriorate required properties of the final suspension and filtrate. For example, flocculation of mineral suspensions results in undesirable decrease of filter-cake dryness and impedes filter cake liquefaction. Flocculation of biosuspensions may decrease the transmission of valuable products from initial suspension to filtrate and may deteriorate filtrate quality. Consequently, pretreatment of suspension by flocculant may decrease the total efficiency of filtration. Alternative pretreatment methods were proposed in order to improve filtration efficiency. For example, pretreatment of suspension with a dispersant is used for preparation of concentrated and flowable filter cakes. Pretreatment of bio-suspensions by high pressure homogenization and other disruption methods may be used for making higher the concentration of valuable intracellular components in filtrate. However, such pretreatment may decrease the filtration rate and the total efficiency of filtration due to increase of the membrane fouling or formation of denser filter cake. Therefore, choice of the optimal pre-treatment method should account both for the filtration rate and the final properties of filtrate and filter cake. This optimisation requires the knowledge of colloidal properties of the feed suspension and dependence of these properties on intensity of various chemical and physical pre-treatments, and it creates a need in the simple method for determination of filterability. It also requires the knowledge of the mechanisms of filtration under various experimental conditions. This thesis is focused on the influence of different pretreatment methods (use of dispersants, high voltage electrical disruption, and high pressure homogenization) on filtration of mineral (kaolin, calcium carbonate) and biological (yeast) suspensions. It also deals with determination of local compression-permeability properties of concentrated suspensions from the centrifugal settling experiments. Investigation of the influence of a dispersant on preparation of flowable and concentrated suspension of kaolin has shown that preparation of kaolin suspensions with concentrations above 70 % wt is unreasonable due to low fluidity of the concentrated suspensions. It was concluded that low fluidity of concentrated suspensions is related to morphology (high aspect ratio) of the kaolin particles. Increase of suspension's concentration results in the percolation of stabilized kaolin particles and in abrupt decrease of fluidity. It was shown that highly concentrated (> 75 % wt) and flowable suspension of calcium carbonate may be prepared by means of dynamic filtration with addition of sodium polyacrylate. The optimal dryness of suspension obtained by dynamic filtration with delayed addition of a dispersant was higher than the optimal dryness of initially deflocculated suspension after its dynamic filtration. It was also observed that continuous treatment of yeast suspension by high voltage electric discharges (HVED) may be used for disruption of the cells and extraction of intracellular bio-products. However, it also results in formation of cell debris and decrease of filtration rate due to internal membrane fouling. Comparison of the novel method of HVED-treatment with classical method of high pressure homogenization (HPH) shows that HPH is more effective disruption method than HVED, since it results in higher extraction of proteins and other bio-products at the same value of disintegration index of yeast cells. However, if the value of disintegration index Z is above 0. 9, filtration of HPH-disrupted yeast suspension is governed by pore blocking mechanism. It results in very low rates of filtration of the maximally HPH-treated suspensions. Also, two independent methods for analysis of the experimental dependencies measured during the centrifugal consolidation were proposed. The dependencies of local compression and permeability characteristics versus solid pressure were estimated by these methods for aqueous suspension of calcium carbonate
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Šelepa, Milan. "Středně dobá předpověď průtoků vody měrným profilem toku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227194.
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The diploma thesis is focused on the long term prediction of mean monthly flows in hydrometric profile for purposes of reservoir control optimization and optimization of reservoir systems. Discharges were predicted using by artificial neural network method. Predicted flows were statistically evaluated by relevant coefficients and then compared with the measured flows for given river hydrometric profiles.
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Huey, Joel W. "Experimental determination of the photolysis rate coefficients of nitrogen dioxide and ozone." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/25764.
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MARTINEZ, LUIS CARLOS CASTILLO. "EXPERIMENTAL DETERMINATION OF TRANSPORTATIONS COEFFICIENTS FOR ICE SLURRY IN PLATE HEAT EXCHANGERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6944@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOA pasta de gelo é uma mistura de água e um aditivo, com finas partículas de gelo, apresentando uma alta densidade de energia térmica. O principal motivo de sua utilização deve-se à combinação do aproveitamento do calor latente na mudança de fase com capacidade de ser bombeado. O presente trabalho trata do estudo experimental sobre a transfe rência de calor e queda de pressão, com mudança de fase, utilizando uma mistura de propileno glicol - água com 13,8% de concentração em peso, num trocador de calor de placas com arranjo em U para 16 placas. Realizaram-se testes de troca de calor com escoamento em paralelo e contra-corrente, para duas condições de fração mássica de gelo e números de Reynolds para a pasta de gelo entre 150 e 425, com diferentes condições de carga térmica. Dos testes foram observados aumentos de até 25% no coeficiente global de troca calor, ao se incrementar a vazão e, conseqüentemente, o número de Reynolds da pasta de gelo. Com o aumento da fração de gelo melhora-se a capacidade de resfriamento, diminuindo o número de Nusselt da pasta de gelo. O coeficiente global de troca, porém, começa a diminuir. Na literatura esta relação ainda não está bem definida. Alguns autores relatam ganhos, perdas ou indiferença no coeficiente global. Resultados do coeficiente global e do número de Nusselt, nos modos paralelo e contra-corrente, não apresentaram grande diferença. A capacidade de resfriamento em contra-corrente foi maior, apresentando valores de efetividade cerca 10% acima dos resultados observados no modo paralelo. Os fatores de atrito encontrados variaram entre 0,030 a 0,085, o que concorda com os resultados apresentados por outros pesquisadores. Como era de se esperar, o fator de atrito diminui com o aumento da vazão mássica e de maneira inversa com o aumento da fração de gelo.
Ice slurry is an aqueous solution from which ice crystals are formed. These crystals possess high energy density, in the form of latent heat. Furthermore, the fact of being a slurry makes it an excellent energy carrier, for it can be easily pumped. The present work presents an experimental procedure to assess the heat transfer and the pressure loss, with phase change, using a mixture of propyleneglycol and water, 13.8% weight, in a U-plate heat exchanger with 16 plates. Tests were carried out for both parallel and counter-flow configurations of the heat exchanger, for two different mass fractions of ice and with Reynolds numbers between 150 and 425 for the slurry. Different thermal loads were considered. The experiments showed increases of up to 25% in the overall heat transfer coeficiente when the slurry flow is increased, with consequent increase in the Reynolds number. By increasing the ice fraction the cooling capacity is improved, reducing the Nusselt number. In the literature, this relationship is not clearly defined, as some authors show gains in the heat exchange coefficient, losses, and some others did not observe any influence on this parameter. Regarding the heat Exchange configuration, i.e., parallel or counter-flow, neither the heat exchange coefficient, nor the Nusselt number suffered major influence. The effectiveness is up to 10% higher for the counter-flow configuration in comparison with the parallel configuration. The figures found for the friction coefficient, between 0,030 and 0,085, are in good agreement with the literature. As expected, the friction coefficient decreases when the mass flow is increased, and increases when the ice fraction is increased.
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Peters, Donald Blandford. "Determination of force coefficients for racing yacht sails using actual force measurements." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12838.
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