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1
Грецких, Светлана Владимировна. "Ослабление статического геомагнитного поля ферромагнитными элементами домов". Thesis, Государственное учреждение "Институт технических проблем магнетизма НАН Украины", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21435.
Повний текст джерелаАнотація:
Диссертация на соискание ученой степени кандидата технических наук по специальности 05.09.05 – теоретическая электротехника. – Национальный технический университет "Харьковский политехнический институт", Харьков, 2016.
Диссертация посвящена математическому моделированию явления ослабления статического геомагнитного поля (ГМП) в помещениях жилых домов и разработке рекомендаций по методам его нормализации до безопасного уровня. Полученные в диссертации результаты в совокупности составляют существенный вклад в решение научно-прикладной задачи теоретической электротехники по моделированию явления ослабления ГМП стальными ферромагнитными элементами конструкций домов и разработки рекомендаций по методам нормализации ГМП в помещениях до безопасного для людей уровня. Основные результаты выполненных в диссертации исследований и практических разработок использованы при выполнении тематического плана ГУ "ИТПМ НАН Украины", в Институте гигиены и медицинской экологии им. А. Н. Марзеева НАМН Украины при разработке "Государственных санитарных правил и норм защиты населения от влияния электромагнитных излучений", при проектировании и строительстве в г. Харькове современных каркасно-монолитных жилых домов с безопасными условиями проживания (ООО "АВУАР"). Результаты работы рекомендованы к применению научным и промышленным учреждениям и предприятиям, выполняющим разработку методов и средств моделирования, расчета и нормализации статического ГМП в жилых домах, проектирующим современные жилые дома с безопасными условиями проживания по магнитному полю.Thesis for scientific degree of candidate of technical sciences, specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2016. The thesis is devoted to mathematical modeling of the phenomenon of weakening of the static geomagnetic field (GMF) in residential homes and to the development of recommendations on how to normalize it to a safe level. The modeling of weakening of the GMF was performed with the help of the equivalent charges method. The cylindrical ferromagnetic column was taken as an example. In the framework of this technique the problem of calculation of the GMF’s induction weakened by extended ferromagnetic elements was solved. The physical parameters of the ferromagnetic column which effect the weakening of GMF are determined. The conditions under which GMF is reduced to the safety level are also determined. This is due to the changes of the GMF’s geometry and reducing of initial magnetic permeability of its material. The Arcadiev method of the effective magnetic permeability for modeling of magneticfield of reinforced concrete columns and intermediate floors was developed. The numerical modeling of static GMF in premises of houses with reinforced concrete structures was performed. The numerical results were experimentally confirmed. The recommendations for normalizing of GMF for creating safe and comfortable living conditions are given. These recommendations should be taken into account in designing modern premises of houses.
2
Грецьких, Світлана Володимирівна. "Ослаблення статичного геомагнітного поля феромагнітними елементами будинків". Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21433.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.05 – теоретична електротехніка. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2016.
Дисертація присвячена математичному моделюванню явища ослаблення статичного геомагнітного поля (ГМП) в приміщеннях житлових будинків та розробці рекомендацій з методів його нормалізації до безпечного рівня. На прикладі циліндричної феромагнітної колони проведено моделювання ослаблення ГМП за допомогою методу еквівалентних (фіктивних) магнітних зарядів та розв’язано задачу розрахунку індукції ГМП, ослабленого протяжними феромагнітними елементами. Визначенні фізичні параметри феромагнітної колони, що впливають на інтенсивність ослаблення ГМП поблизу її поверхні, та умови зменшення до безпечного рівня інтенсивності ослаблення ГМП за рахунок зміни геометрії колони та зменшення початкової магнітної проникності її матеріалу. Здійснено розвиток методу ефективної магнітної проникності Аркадьєва для моделювання магнітного поля залізобетонних колон та міжповерхових перекриттів, армованих сталевим металопрокатом, та виконане чисельне моделювання інтенсивності ослаблення статичного ГМП в приміщеннях житлових будинків з несучими залізобетонними конструкціями і його верифікацію на основі результатів експерименту. Розроблені рекомендації з методів нормалізації ГМП при проектуванні сучасних житлових будинків для створення безпечних та комфортних умов проживання населення за статичним ГМП.Thesis for scientific degree of candidate of technical sciences, specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2016. The thesis is devoted to mathematical modeling of the phenomenon of weakening of the static geomagnetic field (GMF) in residential homes and to the development of recommendations on how to normalize it to a safe level. The modeling of weakening of the GMF was performed with the help of the equivalent charges method. The cylindrical ferromagnetic column was taken as an example. In the framework of this technique the problem of calculation of the GMF’s induction weakened by extended ferromagnetic elements was solved. The physical parameters of the ferromagnetic column which effect the weakening of GMF are determined. The conditions under which GMF is reduced to the safety level are also determined. This is due to the changes of the GMF’s geometry and reducing of initial magnetic permeability of its material. The Arcadiev method of the effective magnetic permeability for modeling of magneticfield of reinforced concrete columns and intermediate floors was developed. The numerical modeling of static GMF in premises of houses with reinforced concrete structures was performed. The numerical results were experimentally confirmed. The recommendations for normalizing of GMF for creating safe and comfortable living conditions are given. These recommendations should be taken into account in designing modern premises of houses.
3
Paleologos, Evangelos Konstantinos 1958. "Effective hydraulic conductivity of bounded, strongly heterogeneous porous media." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/191184.
Повний текст джерелаАнотація:
This dissertation develops analytical expressions for the effective hydraulic conductivity Kₑ of a three-dimensional porous medium bounded by two parallel planes of infinite extent separated by a distance 2a. Head varies randomly along each boundary about a uniform mean value. The log hydraulic conductivity Y forms a homogeneous, statistically anisotropic random field having a variance σᵧ² and principal integral scales λ₁, λ₂, λ₃. Flow is uniform in the mean parallel to the principal coordinate χ₁. A solution is first derived for mildly nonuniform media with σᵧ² ≪ 1 via an approximate form of the 1993 residual flux theory by Neuman and Orr. It is then extended to strongly nonuniform media with arbitrarily large σᵧ² by invoking the Landau-Lifshitz conjecture as Kₑ = KG exp {σᵧ² [1/2 — (D + S)]} . Here, K(G) is the geometric mean of hydraulic conductivities and D and S are domain and surface integrals, respectively. Based on a rigorous limiting analysis we show that when the length scale ratio p = a / λ₁ → 0, Kₑ is equal to the arithmetic mean hydraulic conductivity K(A). This supports the theoretical finding of Neuman and Orr and the numerical result by Desbarats. When ρ → ∞ we obtain expressions for Kₑ that have been previously derived in the stochastic literature for infinite flow domains. For strongly anisotropic media with integral scale ratios ε₂ = λ₂ / λ₁ and ε₃ = λ₃ / λ₁ equal to each other and tending to zero or infinity ( ) i 0) we obtain the closed form solution Kₑ = K(G) exp {σᵧ²[exp(—p) — 0 .5]} . The latter reduces to K(A) when ρ → 0 and tends to the harmonic mean K(H) as ρ → ∞. One can think of the case ε₂ = ε₃ = 0 as mean flow along parallel channels having mutually uncorrelated hydraulic conductivities, and of the case ε₂ = ε₃ → ∞ as mean flow normal to layers having uniform hydraulic conductivities. For statistically isotropic media we show numerically that Kₑ equals K(A) when ρ = 0.01; when ρ ≥ 4, Kₑ = K(G) exp(σᵧ²/6) the three-dimensional infinite domain solution. Our results support the analytical finding of Rubin and Dagan, and predict and explain all related bounded domain numerical results. Finally, contrary to Dagan's assertion, we show that for small ρ boundary effects are extremely important; the absolute value of the surface integral S equals the value of the domain integral D.
4
Song, Young-Tae. "Application of permeability similitude method to centrifuge test." Ohio University / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1178735952.
Повний текст джерела
5
Lancaster, James William. "Multi-scale estimation of effective permeability within the Greenholes Beck catchment." Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369589.
Повний текст джерела
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Rinkevich, A. B., M. I. Samoylovich, and A. F. Belyanin. "Effective Conductivity and Magnetic Permeability of Nanostructured Materials in Magnetic Field." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35340.
Повний текст джерелаАнотація:
The problem of homogenization the nanostructured materials placed in DC magnetic field has been discussed. The experimental data are obtained using metallic superlattices, metal-dielectric thin films and 3D-nanostructured materials. All these materials contain ferro- or ferrimagnetic component. The trans-mission and reflection coefficients were measured on the waves of millimeter waveband. It has been shown that the experimental frequency spectra of the coefficients in zero magnetic field can be described by the effective conductivity and dielectric permittivity. The spectra of ferromagnetic resonance, however, cannot be calculated correctly with the averaged magnetization.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35340
7
Drews, Michael C. "Modelling stress-dependent effective porosity-permeability relationships of metre-scale heterogeneous mudstones." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1672.
Повний текст джерелаАнотація:
The importance of shales and mudstones to applied geosciences and in particular to fluid migration in sedimentary basins has never been more recognized than today. Prominent examples are conventional or unconventional petroleum systems, where shales and mudstones act as source, reservoir or cap rock, but also CO2 and nuclear waste storage or hydrogeology. Despite their importance, shales and mudstones are yet not as far well understood as sandstones or carbonate rocks. In particular, the influence of heterogeneity on fluid migration has been poorly addressed in the past, although many authors have identified and studied heterogeneities in shales and mudstones. Nevertheless, their flow properties are fairly well understood when treated as homogeneous on sample scale (centimetre-scale). Typical flow relevant heterogeneities are grain size and thus petrophysical property (e.g. porosity, permeability, capillary entry pressures) variations due to spatial lithological variation induced by primary and secondary sedimentary structures. In this study we investigate flow relevant heterogeneities of shales and mudstones on submetre scale derived from core and borehole images from an off-shore gas field in the Western Nile Delta, Egypt. Thereby, we combine latest models and published measurements of sample-scale petrophysical properties with interpretation, quantitative analyses, advanced modelling and numerical fluid flow simulation to assess the influence of shale and mudstone heterogeneity on fluid flow and hence, fluid migration, retention and mudstone seal capacity. Additionally, the set of mudstone heterogeneities used in this study has been derived from a combined visual and geostatistical interpretation of more than 500 m of mud-rich core and borehole images. As final results, we deliver stress-dependent effective porosity-permeability relationships for a broad range of shale and mudstone heterogeneities, representative model sizes and resolution as well as measures of uncertainty for each heterogeneity type. Moreover, probability density functions describing where and how these heterogeneities appear in larger scale geological units, such as seismic facies or local depositional environments, are provided. As a key result, heterogeneity and lithological variation have great influences on effective permeability and effective permeability anisotropy (Kh/Kv). Furthermore, our results indicate that mudstone heterogeneity is very common in all investigated larger scale geological units (hemipelagites, levees, channels). Modelling of fluid flow through mud-rich sedimentary basins without inclusion of these sub-metre scale heterogeneities of mudstones can therefore lead to misleading results. Thus, effective porosity-permeability (anisotropy) relationships are provided for different lithological variations and mudstone heterogeneities as a final result.
8
Chen, Chien-Cheng. "An investigation into the relationship between effective stress and permeability of clays." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320827.
Повний текст джерела
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DELGADO, CARLOS WILFREDO CARRILLO. "DEVELOPMENT OF AN EQUIPMENT FOR THE STUDY OF EFFECTIVE PERMEABILITY IN MULTIPHASE MEDIA." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2000. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2032@1.
Повний текст джерелаАнотація:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOO trabalho apresenta uma ampla revisão de conceitos básicos associados ao fluxo multifásico (fluxo simultâneo de dois ou mais fluidos) em meios porosos, bem como técnicas de ensaios e equipamentos utilizados na determinação de permeabilidades efetiva e absoluta em solos saturados e não saturados com água. Com base nesta revisão, e visando a medida da permeabilidade de solos não saturados submetidos a fluxo de misturas gasolina-álcool, foi projetados, construído e colocado em operação um sistema de permeâmetros de parede flexível com controle de sucção; foi desenvolvido um software de controle e implementando um sistema automático de monitoramento da instrumentação eletrônica utilizada para medidas de variação de volume, de pressões e de deslocamentos axiais das amostras desolo; foi implementado um sistema de bomba de fluxo para aplicação de vazões constantes nos ensaios de permeabilidade, e forma desenvolvidos sistemas de medição do volume dos líquidos e gases passando pela amostra sob diferentes gradientes de pressão. Todos os desenvolvimentos projetados e implementados são descritos em detalhe. Características de uso dos equipamentos e aspectos de calibração da instrumentação eletrônica e demais acessórios são discutidos, procurando-se definir limites de trabalhabilidade, eventuais deficiências e técnicas alternativas de ensaios envolvendo o uso de misturas álcool gasolina. Visando avaliar o comportamento dos equipamentos e acessórios desenvolvidos, apresenta-se e discute-se resultados de um programa experimental envolvendo a) o uso de amostras de um solo inerte, incompressível dentro dos níveis de tensões efetivas aplicadas, preparadas em laboratório utilizando técnicas especiais de modo a se obter uma estrutura repetitiva, fracamente cimentada, simulando os solos residuais de gnaisse; b) execução de ensaios de vazão constante visando a determinação da permeabilidade absoluta de amostras saturadas utilizando como fluidos permeantes água, ar gasolina e álcool; c) execução de ensaios de vazão constante visando a determinação das permeabilidades efetivas à água e ao ar de amostras não saturadas, submetidas a sucções constantes variando de cerca de 10 a 60 kPa. Os resultados obtidos indicam que o equipamento desenvolvido e as técnicas experimentais implementadas constituem ferramentas versáteis que possibilitam a determinação direta das permeabilidades absolutas e efetivas de forma relativamente simples e confiáveis.
This work presents a wide revision of basic concepts associated to the multiphase flow (simultaneous flow of two or more fluids) in porous media as well as techniques of test and equipment s used in the determination of effective and absolute permeability in saturated and not saturated soils with water.With basis in this revision, and locking for the measure of saturated soils permeability submitted to flow of mixtures gasoline-alcohol, it was projected, built and placed in operation a system of flexible wall permeameters with suction control; a control software was developed and implementing an automatic system of monitoring of the electronic instrumentation used for measures of change volume, pressures and axial displacements of the soil samples; a flow pump system was implemented for application of constant rate in the permeability test, and systems of measurement of the volume of the liquids and gases were developed going by the sample under different pressure gradients.All the projected developments and implemented are described in detail. Characteristics of the used equipment s and calibration aspects of the electronic instrumentation and other accessories are discussed, trying to define workability limits, eventual deficiencies and techniques alternatives of testing involving the use of alcohol gasoline mixtures. Look in for evaluate the performance of equipment s and developed accessories, are presented and it is discussed results of an experimental program involving a) the use of samples of a inert soil, incompressible between levels of applied effective tensions,prepared in labortory using special techniques in way obtaining a repetitive structure, weakly cemented, simulating the residual soils of gnaisse; b) execution of constant rate test looking for the absolute permeability determination of saturated samples using as percolate fluids water, air, gasoline and alcohol; c) execution of constant rate test looking for the determination of the effective permeability to the water and the air of non saturated samples, submitted to constant suctions varying about 10 to 60 kPa.The obtained results indicate that the developed equipment and the implemented experimental techniques constitute versatile tools that make possible the direct determination of the absolute and effective permeabilities in way relatively simple and you trusted.
EL trabajo presenta una amplia revisión de conceptos básicos asociados al flujo multifásico (flujo simultáneo de Dos o más fluidos) en medios porosos, así como técnicas de ensayos y equipamentos utilizados en la determinación de permeabilidades efectiva y absoluta en suelos saturados y no saturados con agua. Con el objetivo de medir la permeabilidad de suelos no saturados sometidos a flujo de mezclas de gasolina y alcohol, fue proyectados, construido y colocado en operación un sistema de permeámetros de pared flexible con control de succión; se desarrolló un software de control y se implementó un sistema automático de monitoramiento de la instrumentación eletrónica utilizada para medidas de variación de volumen, de presiones y de desplazamientos axiales de las muestras de suelo. Se implementó además; un sistema de bomba de flujo para aplicación de desbordamientos constantes en los ensayos de permeabilidad, y se deasarrollaron sistemas de medición del volumen de los líquidos y gases pasando por la muestra bajo diferentes gradientes de presión. Se detallan todos los desarrollos proyectados e implementaciones. Se discute las características de uso de los equipamentos y aspectos de calibración de la instrumentación eletrónica y demás accesorios, con el objetivo de definir límites de trabajabilidad, eventuales deficiencias y técnicas alternativas de ensayos que envuelven el uso de mezclas de alcohol u gasolina. Para evaluar el comportamiento de los equipos y accesorios desarrollados, se presentan y discuten los resultados de un programa experimental que considera a) el uso de muestras de un suelo inerte, incompresible dentro de los níveles de tensiones efectivas que fueron aplicadas, preparadas en laboratorio utilizando técnicas especiales para obtener una extructura repetitiva, debilmente cimentada, simulando suelos residuales de gnaise; b) ejecución de ensayos de desbordamiento constante visando la determinación de la permeabilidad absoluta de muestras saturadas utilizando como fluidos permeantes agua, ar gasolina y álcool; c) ejecución de ensayos de desbordamiento constante con el objetivo de determinar las permeabilidades efectivas a agua y aire de muestras no saturadas, sometidas a succiones constantes variando entre 10 a 60 kPa. Los resultados obtenidos indican que el equipo desarrollado y las técnicas experimentales implementadas constituyen herramientas versátiles que hacen posible la determinación directa de las permeabilidades absolutas y efectivas de forma relativamente simple y confiables.
10
Song, Young-Tae. "Application of permeabilty similitude method to centrifuge test." Ohio : Ohio University, 1994. http://www.ohiolink.edu/etd/view.cgi?ohiou1178735952.
Повний текст джерела
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Carballo, Salas Jose Gilberto. "Alleviation of effective permeability reduction of gas-condensate due to condensate buildup near wellbore." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3245.
Повний текст джерелаАнотація:
When the reservoir pressure is decreased below dew point pressure of the gas near
the wellbore, gas-condensate wells start to decrease production because condensate is
separated from the gas around the wellbore causing a decrease in gas relative
permeability. This effect is more dramatic if the permeability of the reservoir is low. The
idea proposed for reducing this problem is to eliminate the irreducible water saturation
near the wellbore to leave more space for the gas to flow and therefore increase the
productivity of the well. In this research a simulation study was performed to determine
the range of permeabilities where the cylinder of condensate will seriously affect the
wellÂs productivity, and the distance the removal of water around the wellbore has to be
extended in order to have acceleration of production and an increase in the final reserves.
A compositional-radial reservoir was simulated with one well in the center of 109
grids. Three gas-condensate fluids with different heptanes plus compositions ( 4, 8 and 11
mole %), and two irreducible water saturations were used. The fitting of the Equation of
State (EOS) was performed using the method proposed by Aguilar and McCain. Several
simulations were performed with several permeabilities to determine the permeabilities
for which the productivity is not affected by the presence of the cylinder of condensate.
At constant permeability, various radii of a region of zero initial water saturation
around the wellbore were simulated and comparisons of the effects of removal of
irreducible water on productivity were made.
Reservoirs with permeabilities lower than 100 mD showed a reduction in the
ultimate reserves due to the cylinder of condensate. The optimal radius of water removal
depends on the fluid composition and the irreducible water saturation of the reservoir.
The expected increase in reserves due to water removal varies from 10 to 80 % for gas
production and from 4 to 30% for condensate production.
12
Murray, Gordon Bruce. "The development of an estimation method for the saturated hydraulic conductivity of selected Nova Scotia soils /." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59983.
Повний текст джерелаАнотація:
An estimation method for predicting the saturated hydraulic conductivity (Ksat) of the soil was developed for common Nova Scotia soil types by examination of historical Ksat records. Detailed statistical analysis was performed to develop useful predictive models for Ksat based on soil physical properties and to determine the confidence limits for specific horizon-soil type combinations. Sensitivity analysis of the Hooghoudt equation was then performed to establish Ksat classes to which the confidence limits could be assigned to complete the development of the estimation method.Model development processes proved unsuccessful due to the influence of factors not considered by the model due to their qualitative nature. Independent field testing of the estimation method with respect to core and Guelph permeameter measurement techniques produced measured values within the same class as the estimated value 34% of the time for both techniques and values within one estimated class or less 70 and 76% of the time for core and permeameter techniques respectively.
13
Teimoori, Sangani Ahmad Petroleum Engineering Faculty of Engineering UNSW. "Calculation of the effective permeability and simulation of fluid flow in naturally fractured reservoirs." Awarded by:University of New South Wales. School of Petroleum Engineering, 2005. http://handle.unsw.edu.au/1959.4/22408.
Повний текст джерелаАнотація:
This thesis is aimed to calculate the effective permeability tensor and to simulate the fluid flow in naturally fractured reservoirs. This requires an understanding of the mechanisms of fluid flow in naturally fractured reservoirs and the detailed properties of individual fractures and matrix porous media. This study has been carried out to address the issues and difficulties faced by previous methods; to establish possible answers to minimise the difficulties; and hence, to improve the efficiency of reservoir simulation through the use of properties of individual fractures. The methodology used in this study combines several mathematical and numerical techniques like the boundary element method, periodic boundary conditions, and the control volume mixed finite element method. This study has contributed to knowledge in the calculation of the effective permeability and simulation of fluid flow in naturally fractured reservoirs through the development of two algorithms. The first algorithm calculates the effective permeability tensor by use of properties of arbitrary oriented fractures (location, size and orientation). It includes all multi-scaled fractures and considers the appropriate method of analysis for each type of fracture (short, medium and long). In this study a characterisation module which provides the detail information for individual fractures is incorporated. The effective permeability algorithm accounts for fluid flows in the matrix, between the matrix and the fracture and disconnected fractures on effective permeability. It also accounts for the properties of individual fractures in calculation of the effective permeability tensor. The second algorithm simulates flow of single-phase fluid in naturally fractured reservoirs by use of the effective permeability tensor. This algorithm takes full advantage of the control volume discretisation technique and the mixed finite element method in calculation of pressure and fluid flow velocity in each grid block. It accounts for the continuity of flux between the neighbouring blocks and has the advantage of calculation of fluid velocity and pressure, directly from a system of first order equations (Darcy???s law and conservation of mass???s law). The application of the effective permeability tensor in the second algorithm allows us the simulation of fluid flow in naturally fractured reservoirs with large number of multi-scale fractures. The fluid pressure and velocity distributions obtained from this study are important and can considered for further studies in hydraulic fracturing and production optimization of NFRs.
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Xu, Chuntang. "Estimation of effective compressibility and permeability of porous materials with differential acoustic resonance spectroscopy /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Jarzemba, Mark Steven. "A method for measuring the radon hazard of low permeability soils /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487848078449258.
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Mckernan, Rosanne. "An experimental investigation into the stress dependent fluid transport properties of mudstones." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/an-experimental-investigation-into-the-stress-dependent-fluid-transport-properties-of-mudstones(17efbf46-29a3-44d1-afd3-194709418c90).html.
Повний текст джерелаАнотація:
Measuring transport properties of rock samples under stress is essential to understanding and predicting the migration of fluids within the Earth's crust. Mudrocks play an essential role in petroleum systems as they are often the source rock and may act as a seal due to their low permeability. With increasing production from unconventional reservoirs where the mudrock is source, reservoir and seal, there is now even greater demand to understand the permeability and storativity of mudstones and tight sandstones. When hydraulic fracture treatment is used to enhance production, flow of hydrocarbons into the fractures will be ultimately controlled by the matrix permeability. Knowledge of the fluid transport properties of mudstones is currently hindered by a scarcity of published experimental data. In this thesis, a combination of permeability and ultrasonic velocity measurements allied with image analysis is used to distinguish the primary microstructural controls on effective stress dependent permeability. Permeabilities of cylindrical samples of Whitby Mudstone and Eagle Ford Shale have been measured using the oscillating pore pressure method at confining pressures ranging between 30-95 MPa and pore pressures ranging between 1-80 MPa. The results show that samples must be pressure cycled in order to obtain a reproducible behaviour, after which the relationship between permeability and effective stress can be described by an exponential law. The permeability of the Whitby Mudstone samples ranges between 7 ×10-21 m2 and 2 ×10-19 m2 (7 nd to 188 nd) and decreases by ~1 order of magnitude across the applied effective stress range. The permeability of the Eagle Ford Shale samples is slightly higher ranging between 2 ×10-18 m2 and 42 ×10-18 m2 (2 μd to 42 μd) and decreases by half an order of magnitude across the applied effective stress range. Permeability is shown to be more sensitive to changes in pore pressure than changes in confining pressure yielding values of alpha between 1.1-2.1 for Whitby Mudstone and 1.6-4.6 for Eagle Ford Shale. Gas slippage (Klinkenberg) effects are restricted to pore pressures below 10 MPa in the Whitby Mudstone and therefore do not affect the results presented. The permeability-effective stress relationship is thus empirically described using a modified effective stress law in terms of confining pressure, pore pressure and a Klinkenberg effect. Use of a simple reservoir model demonstrates that if pressure dependent permeability is not taken into account, substantial overestimation of gas flow rate and original gas in place will be made from well tests. Changes in ultrasonic velocity and pore volume were related to the observed loss of permeability with increasing effective stress, providing further insight into the nature of the permeability-controlling pore network. Combining the petrophysical data with pore conductivity modelling and microstructural analysis shows that at low effective stresses, permeability is controlled by a network of long, thin crack-like pores associated with grain boundaries. At high effective stresses, these cracks are closed and fluid is restricted to flowing through a less permeable network of higher aspect ratio, stiffer, nm-scale pores in the clay matrix. Applying the methods developed in the present work to different mudstones with a range of compositions and textures will help to refine understanding of the variability in fluid-conducting pore networks, thereby advancing the interpretation of data from well logs and well tests used for reservoir evaluation.
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Harmon, C. Reid Jr. "IPU/LTB:a method for reducing effective memory latency." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5352.
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Hong, Bryan Y. "An effective noise filtering method for mine detection." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5576.
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Approved for public release; distribution is unlimited.Automatic detection of sea mines in coastal regions is difficult due to highly varying sea bottom conditions present in the underwater environment. Detection systems must be able to discriminate objects that vary in size, shape, and orientation from naturally occurring and man-made clutter. Additionally, these automated systems must be computationally efficient to be incorporated into Unmanned Aerial Vehicle (UAV) sensor systems characterized by high sensor data-rates and limited processing abilities. Commonly used noise filters largely depend on the window (or neighborhood) size, which makes the mine detection ineffective. Using the bi-dimensional empirical mode decomposition (BEMD) analysis, an effective, robust sea mine detection system can be created. A family of decomposed images is generated and applied to optical lidar image data from the Rapid, Overt, Airborne, Reconnaissance (ROAR) experiment supplied by Naval Surface Warfare Center, Panama City. These decompositions project key image features, geometrically defined structures with orientations, and localized information into distinct orthogonal components or feature subspaces of the image. Application of the BEMD method to the analysis on side scan sonar data is also provided. Accurate detection and classification of mines is time consuming and requires divers or Autonomous Underwater Vehicles (AUV) in the water. The navy continues to pursue more expedient methods in mine countermeasures, and with airborne lidar, a surf zone (SZ) and landing zone can be quickly surveyed for possible mines. In the near surf zone, all possible mines can be quickly neutralized by dropping guided munitions, eliminating the need to send divers or AUVs to verify contacts. Still, the need for improved methods of detection and classification is needed. BEMD, a relatively new method of signal analysis developed about fifteen years ago, was tested on lidar imagery from the ROAR experiment to look for any improvements in detecting and classifying mines.
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Zhang, Hao. "INVESTIGATION TO A COST-EFFECTIVE 3D MICROMACHINING METHOD." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1372250848.
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Burlaka, Iryna. "Discussion as an effective foreign language teaching method." Thesis, Київський національний університет технологій та дизайну, 2019. https://er.knutd.edu.ua/handle/123456789/13039.
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Bosch, David Dean 1958. "Derivation and application of effective parameters for modeling moisture flow in heterogeneous unsaturated porous media." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/191158.
Повний текст джерелаАнотація:
Spatial variability of porous media often prevents precise physical characterization of the system. In order to model moisture and solute transport through this media, certain sacrifices in precision must be made. Physical characteristics of the system must be averaged over large scales, lumping the small scale variability into the large scale characterization. Although this precludes a precise definition of the small scale flow characteristics, parameterization is much more attainable. This study addresses methods for determining effective hydraulic conductivity of unsaturated porous media. Effective conductivity is used to describe the large scale behavior of the system. Different methods for calculating the effective conductivity are presented and compared. Results indicate that the unit mean gradient method produces good estimates of the effective conductivity and can be applied using limited field data. The zone of correlation of the hydraulic parameters can be used in experimental design to minimize the errors associated with estimation of the mean pressure. An inverse method for evaluating the optimum effective hydraulic parameters is presented. Results indicate the optimization procedure is more sensitive to wetting than to drying conditions. Because of interaction between the hydraulic parameters, concurrent optimization of more than two of the parameters based on soil pressure data alone is not advised. Anisotropy in an unsaturated soil was found to be a function of the profile mean soil pressure. Results indicate the effective conductivity for flow parallel to soil layering can be estimated from the arithmetic mean of the unsaturated conductivity values for each of the layers and is between the harmonic and geometric means of these data for flow perpendicular to the layering. Estimates of the effective unsaturated hydraulic conductivity obtained through stochastic analysis agreed well with simulation results. Deviations between the stochastic predictions and simulation results are larger when the variability of the soil profile is greater and begin to deviate significantly when the variance of ln K(ψ₀) exceeds 5.0 and the variance of a exceeds 0.02 1/cm².
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Pendse, Nachiket Vishwas. "An effective dimensional inspection method based on zone fitting." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3239.
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Coordinate measuring machines are widely used to generate data points from an actual surface. The generated measurement data must be analyzed to yield critical geometric deviations of the measured part according to the requirements specified by the designer. However, ANSI standards do not specify the methods that should be used to evaluate the tolerances. The coordinate measuring machines employ different verification algorithms which may yield different results. Functional requirements or assembly conditions on a manufactured part are normally translated into geometric constraints to which the part must conform. Minimum zone evaluation technique is used when the measured data is regarded as an exact copy of the actual surface and the tolerance zone is represented as geometric constraints on the data.
In the present study, a new zone-fitting algorithm is proposed. The algorithm evaluates the minimum zone that encompasses the set of measured points from the actual surface. The search for the rigid body transformation that places the set of points in the zone is modeled as a nonlinear optimization problem. The algorithm is employed to find the form tolerance of 2-D (line, circle) as well as 3-D geometries (cylinder). It is also used to propose an inspection methodology for turbine blades. By constraining the transformation parameters, the proposed methodology determines whether the points measured at the 2-D cross-sections fit in the corresponding tolerance zones simultaneously.
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陳惠結 and Wai-kit Chan. "The most effective method to improve antiretroviral drug adherence." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40720329.
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Harmon, C. Reid. "IPU/LTB a method for reducing effective memory latency /." Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180020/unrestricted/harmon%5Fc%5Fr%5F200312%Fphd.pdf.
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Chan, Wai-kit. "The most effective method to improve antiretroviral drug adherence." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40720329.
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Luong, Suzen. "Is arbitration an effective method to resolve employment disputes?" access full-text access abstract and table of contents, 2008. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?ma-slw-b23454416a.pdf.
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Zhang, Runtong. "Measurement of effective diffusivity : chromatographic method (pellets & monoliths)." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608352.
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This thesis aims to find out the effective diffusivity (Deff) of a porous material – γ-alumina, using an unsteady state method with two inert gases at ambient condition with no reactions. For porous materials, Deff is important because it determines the amount of reactants that transfers to the surface of pores. When Deff is known, the apparent tortuosity factor of γ-alumina is calculated using the parallel pore model. The apparent tortuosity factor is important because: (a) it can be used to back-calculate Deff at reacting conditions; (b) once Deff with reactions is known, the Thiele modulus can be calculated and hence the global reaction rate can be found; (c) apparent tortuosity factor is also important for modelling purposes (e.g. modelling a packed-bed column or a catalytic combustion reactor packed with porous γ-alumina in various shapes and monoliths). Experimental measurements were performed to determine the effective diffusivity of a binary pair of non-reacting gases (He in N2, and N2 in He) in spherical γ-alumina pellets (1 mm diameter), and in γ-alumina washcoated monoliths (washcoat thickness 20 to 60 µm, on 400 cpsi (cells per square inch) cordierite support). The method used is based on the chromatographic technique, where a gas flows through a tube, which is packed with the sample to be tested. A pulse of tracer gas is injected (e.g. using sample loops: 0.1, 0.2, 0.5 ml) and by using an on-line mass spectrometer the response in the outlet of the packed bed is monitored over time. For the spherical pellets, the tube i.d. = 13.8 mm and the packed bed depths were 200 and 400 mm. For monoliths the tube i.d. = 7 mm and the packed lengths were 500 and 1000 mm. When the chromatographic technique was applied to the monoliths, it was observed that experimental errors can be significant, and it is very difficult to interpret the data. However, the technique worked well with the spherical pellets, and the effective diffusivity of He in N2 was 0.75 – 1.38 × 10-7 m2 s-1, and for N2 in He was 1.81 – 3.10 × 10-7 m2 s-1. Using the parallel pore model to back-calculate the apparent tortuosity factor, then a value between 5 to 9.5 was found for the pellets.
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Ramberg, Erik. "Creating an effective quality management method within software development." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165338.
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This thesis answers how to create an effective quality assurance method within software development, especially games development. The work has mainly consisted of interviews with employees and others within the same business as well as studies of literature. The thesis also describes how the new quality management method got management acceptance, how it was implemented, what happened and recommendations. The work was conducted in 2007 and the result in this report is still, eight years later, used by the company.Denna rapport berättar hur man skapar en effektiv kvalitetssäkringsmetod inom mjukvaruutveckling, särskilt spelutveckling. Arbetet har i huvudsak bestått av intervjuer med företagets anställda såväl som andra inom samma bransch samt litteraturstudier. Rapporten beskriver även hur den nya kvalitetssäkringsmetoden förankrades i organisationen, hur den implementerades, vad som hände sen samt rekommendationer. Arbetet utfördes 2007 och såsom framgår i denna rapport används resultatet, åtta år senare, fortfarande av företaget.
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Ullsten, Henrik. "Barrier Plastics, Processing of Wheat Gluten and A New Method to Measure Permeability." Licentiate thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1778.
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One way to extend the shelf life for foodstuff is to usemodified atmosphere packaging (MAP). It is important that MAPare gas tight or in some rare cases permselective to preservethe right gas mix. To be able to determine how the gas contentchanges it is essential to know the gas permeability of thewhole packaging with effects from seals, folds and possibleplasticisation effects from the products.
In the first part of the study a new technique fordetermining oxygen and carbon dioxide permeability of flexiblepackaging was developed. The method was tested on very-lowdensity, low density and high density polyethylene pouches. Thepouch head-space and pouch volume of carbon-dioxide-filledpouches were measured as a function of time until anequilibrium pouch gas composition was established. Permeabilitywere obtained from the rates of carbondioxide loss and oxygenuptake. HSP-method permeability values were in good agreementwith those obtained from traditional flat-film permeabilitytechniques. The HSP-method was found to be a valuable tool fordetermining and quantifying changes in carbon dioxide andoxygen pouch barrier properties due, for example, to theexposure to olive oil or due to the existence of poorwelds.
When use of MAP are growing the demands for suitable andcheap gas barrier materials are increasing. Films made fromwheat gluten, which is a by-product from the manufacture ofethanol and sweeteners, has low oxygen permeability propertiesin dry conditions and that makes it interesting as a packagingbarrier. Several studies have been performed on solution castedwheat gluten films, but to get a new material on the market itis of great importance that the material is adapted to thepresent process equipment, such as plastic extruders. Thesecond part of the study deals with a way to expand theprocessing window of wheat gluten plastisazed withglycerol.
The temperature -processing window of glycerol-plasticizedwheat gluten was increased by the use of a well-known scorchretarder, salicylic acid. It was possible to extrude 30 wt.%glycerol-wheat gluten films with a die-head temperature as highas 135°C, rather than 95°C, by incorporating only 1%salicylic acid. Small effects of shear induced heating duringextrusion suggested that the acid acted as a lubricator.Chemilumiscence, in turn, showed that it also had an effect onthe heat-induced chemical changes of gluten. Tensile tests onextrudates revealed that the substantially enhanced processingtemperature was achieved to the expense of a slightly reducedductility. Tensile tests were obtained on compression-moldedsamples containing 30wt% glycerol and an additional 2.5-5% ofglycerol, salicylic acid or sulfonamide. The tensile tests,performed during the first 30 min after molding, did not revealany scorch retarding effects. However, the retarders did reducethe level of aggregation and crosslinking as compared toglycerol, observed by that fact that the fracture stress wasconsistently lower for salicylic acid and sulfonamide comparedto glycerol. The complex shearmodulus increased more slowlyabove 110-120°C with increasing salicylic acid content,indicating that it did have a scorch retarding effect.
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Benrewin, Mabruk Ahmed. "Modelling of a new petrophysical method for measuring relative permeability and capillary pressure." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/679.
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Farah, Nicolas. "Flow Modelling in Low Permeability Unconventional Reservoirs." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066503/document.
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Les réservoirs non-conventionnels présentent un milieu fracturé à multi-échelles, y compris des fractures stimulées et des fractures naturelles, augmentant l'hétérogénéité et la complexité de la simulation de réservoir. Ce travail propose un modèle unique et simple tout en tenant compte des paramètres clés d'un réservoir, tels que l'orientation des fractures, l'anisotropie et la faible perméabilité du réservoir. L'échange matrice-fracture n'est pas correctement modélisé en utilisation les modèles Discrete Fracture Model (DFM) standards en raison de la très faible perméabilité. Dans ce travail nous proposons l'extension de la méthode MINC (Multiple interagissant Continua) aux modèles DFM afin d'améliorer l'échange matrice-fracture. Notre DFM basé sur la méthode MINC, est un modèle triple porosité où les fractures de très grandes conductivités sont explicitement discrétisées et le reste est homogénéisé. Autrement aux modèles standards et afin d'améliorer l'échange de flux entre la matrice et la fracture, une maille matrice est subdivisé selon une fonction de proximité en tenant compte de la distribution des fractures. Notamment, notre approche est particulièrement utile pour les simulations multiphasique avec un changement de phase dans l'échange matrice/fracture, qui ne peut pas être simulé avec une approche standard. Enfin, nous avons appliqué notre approche pour un cas DFN synthétique dans un réservoir de gaz à condensat et un réservoir tight-oil. Un bon accord a été observé en comparant nos résultats à des solutions de référence obtenues avec des maillages très finsUnconventional low permeability reservoirs present a multi-scale fractured media, including stimulated fractures and natural fractures of various sizes, increasing the heterogeneity and the complexity of the reservoir simulation. This work proposes a methodology to address this challenge, taking into account reservoir key parameters such as fractures locations, orientation, anisotropy and low permeability matrix in a unique model as simple as possible. Using standard Discrete Fracture Models (DFMs), the matrix-fracture interaction is not properly handled due to the large grid cells and very low matrix permeability. In this work, we extended the MINC (Multiple INteracting Continua) method to the DFM in order to improve the matrix-fracture flow exchange. Our DFM based on a MINC proximity function is computed by taking into account all discrete fractures, within a triple-porosity model where the propped fractures are explicitly discretized and other fractures are homogenized. In order to improve the flow exchange between the matrix and fracture media, the matrix grid cell is subdivided according to the MINC proximity function based on the distance to all discrete fractures, by using randomly sampled points. Our approach is particularly useful for multi-phase flow simulations in matrix-fracture interaction with phase change, which cannot be handled by a standard approach. Finally, we applied our technique to synthetic DFM case in a retrograde gas and a tight-oil reservoirs. A good agreement is observed by comparing our results to a reference solution where very fine grid cells were used
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Verbytska, A. "Inflation targeting as an effective method of ensuring price stability." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/48939.
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Hedlund, André. "Effective Finite Element Analysis Workflow for Structural Mechanics." Thesis, Uppsala universitet, Tillämpad mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-254399.
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The Finite Element Method (FEM) is a technique for finding the approximate solution of differential equations. It is commonly used in structural analysis to evaluate the deformation and internal stresses of a structure that is subject to outer loads. This thesis investigates the Finite Element Analysis (FEA) workflow that is used at Andritz Hydro AB, with the objective to find solutions that make the workflow more time effective. The current workflow utilises Siemens NX and Salomé for pre- and post-processing, and Code Aster as the FEM solver. Two different approaches that improve the workflow are presented. The first suggest that the entire FEA workflow is migrated to NX using the built-in FEM package of NX called Advanced Simulation. The second approach utilises the Salomé API (Application Programming Interface) to create a customised toolbox (a script containing several functions) that automate several repetitive and cumbersome steps of the workflow, therefore effectively reducing the time that is required by the analyst to perform FEA. Due to the positive results and ease-of-use, the Salomé toolbox is preferred over the license cost and steep learning curve that is related to NX and Advanced Simulation.
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VALVERDE, VIVIANA TORRALBA. "EFFECT OF THE COMPACTION METHOD ON THE PERMEABILITY OF AN ORGANIC COMPOUND-COLLUVIONAR SOIL MIXTURE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9632@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO liner é um elemento de extrema importância no processo construtivo de um aterro sanitário, pois funciona como uma barreira capaz de impedir a percolação de agentes contaminantes através do subsolo. Os liners ou camadas impermeabilizantes são geralmente construídos a partir de materiais que possuem baixa permeabilidade. A escolha de um material adequado, assim como o controle dos processos construtivos são indispensáveis para garantir um bom desempenho da camada impermeabilizante. O processo de compactação é de extrema importância neste tipo de obra geotécnica. Os ensaios de compactação realizados em laboratório têm como objetivo reproduzir as condições de campo, no entanto, em numerosos casos há diferenças importantes entre os mecanismos de compactação utilizados, na preparação do material antes do processo de densificação e nas características das amostras, o que gera como conseqüência discrepâncias nos valores de permeabilidade de campo com os de laboratório. O objetivo principal do presente estudo é avaliar experimentalmente a influência de dois mecanismos diferentes de compactação (dinâmico, com o Proctor Normal e estático, com o método de compactação por pisoteamento) nos valores de permeabilidade de um solo coluvionar e de um composto orgânico para seu eventual uso em um liner. Os ensaios foram realizados em corpos de prova com diferentes teores de umidade, preparados com solo coletado no campo Experimental II da PUC-Rio, com composto orgânico produzido a partir do processo de compostagem da grama do Aeroporto Internacional Galeão (RJ), e com misturas em diferentes proporções de ambos os materiais.
The liner is one of the most important elements in a sanitary landfill project, since it works as a barrier capable to impede seepage of pollutant substances through the subsurface. This element is usually built with materials that have low permeability. The choice of the right material as well as the control and supervision of the constructive processes are fundamental to achieve a good liner performance. The compaction process is extremely important in this type of geotechnical impoundment. Laboratory compaction intends to reproduce the field conditions; however, in some cases, there happen to be important differences between the compaction mechanisms used, the preparation of the material before the densification process and the specimens characteristics, which cause discrepancies between the permeability values obtained in the field and the ones obtained in the laboratory. The main objective of this study is to evaluate experimentally the effect of two different compaction mechanisms (dynamic, with standard Proctor and static, with the kneading compaction method) in the hydraulic conductivity of a colluvionar soil and an organic compound for their eventual use in a liner. The tests were executed using specimens with different water contents, prepared with colluvionar soil extracted from the Experimental Field II at the PUC-Rio, with the organic compound, and with mixtures of both materials in different proportions.
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Andrikonis, Julius. "Effective Method to Obtain Terminating Proof-Search in Transitive Multimodal Logics." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20111227_091412-58067.
Повний текст джерелаАнотація:
In the dissertation epistemic logics with central agent interaction axiom are analysed. The research covers multimodal logics Kn, Tn, K4n and S4n. The aim of the work is finite derivation search sequent calculi for the mentioned logics. A new method to obtain the termination of derivation search is presented in the thesis and this method is applied to the mentioned logics as well as to monomodal logics K4 and S4.Disertacijoje nagrinėjamos žinių logikos su centrinio agento sąveikos aksioma. Tyrimas apima multimodalines logikas Kn, Tn, K4n ir S4n. Disertacijos tikslas – baigtinės išvedimo paieškos sekvenciniai skaičiavimai minėtoms logikoms. Darbe pristatomas naujas išvedimo paieškos baigtinumą užtikrinantis metodas, kuris yra pritaikomas minėtoms logikoms, o taip pat monomodalinėms logikoms K4 ir S4.
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Pittalis, Stefano [Verfasser]. "Spinor-orbital functionals and the optimized effective potential method / Stefano Pittalis." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023049325/34.
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Sato, Shuji. "Effective three-dimensional electric field analysis by surface charge simulation method /." [S.l.] : [s.n.], 1987. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8221.
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Zhang, Xiujuan, and 張秀娟. "An effective design method for components made of a multiphase perfectmaterial." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30267018.
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Thatcher, William H. IV. "An Inquiry of the Conventional Cavity Perturbation Method, with Direct Application to Various Liquid Samples." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471347258.
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Genova, Barazarte Ezequiel. "Stochastic modeling of the variation of velocity and permeability as a function of effective pressure using the Bed-of-Nails asperity-deformation model." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1525.
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Demirtas, Afsin Emrah. "A Comparative Study On Direct Analysis Method And Effective Length Method In One-story Semi-rigid Frames." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614723/index.pdf.
Повний текст джерелаАнотація:
For steel structures, stability is a very important concept since many steel structures are governed by stability limit states. Therefore, stability of a structure should be assessed carefully considering all parameters that affect the stability of the structure. The most important of these parameters can be listed as geometric imperfections, member inelasticity and connection rigidity. Geometric imperfections and member inelasticity are taken into account with the stability method used in the design. At this point, the stability methods gain importance. The Direct Analysis Method, the default stability method in 2010 AISC Specification, is a new, more transparent and more straightforward method, which captures the real structure behavior better than Effective Length Method. In this thesis, a study has been conducted on the semi-rigid
steel frames to compare Direct Analysis Method and Effective Length Method and to investigate the effect of flexible connections to stability. Four frames are designed for different connection rigidities with stability methods existing in the 2010 AISC Specification: Direct Analysis Method and Effective Length Method. At the end,conclusions are drawn about the comparison of these two stability methods and the effect of semi-rigid connections to stability.
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Lai, Benjamin Ph D. Massachusetts Institute of Technology. "An effective overlapping finite element method : the method of finite spheres for three-dimensional linear elasticity problems." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103439.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 119-123).
The method of finite spheres is an effective overlapping finite element method developed to overcome challenges in mesh-based numerical methods. Commonly recognized challenges include mesh generation for geometrically complex domains, severe element distortion in nonlinear analysis with large strain effects, and modeling problems involving discontinuities and singularities which require mesh alignment and refinement. Substantial research efforts have been focused on addressing these issues, resulting in the introduction of numerous meshless methods. The ultimate purpose of the method of finite spheres is to be distinguished as a reliable and efficient meshless computational technique for the solution of boundary value problems on complex domains, to supplement the capabilities of the standard finite element method. The reliability of the method of finite spheres was previously verified for one- and two-dimensional linear static analysis of solids and fluids. The objective of this thesis is to demonstrate the reliability and effectiveness of the method of finite spheres for the solution of practical three-dimensional linear elasticity problems. An effective local approximation space, which is multiplied by the Shepard partition of unity function, is presented for the construction of three-dimensional interpolation functions. The piecewise Gauss-Legendre quadrature rule, a simple and efficient scheme for the integration of complicated non polynomial basis functions, is introduced for three-dimensional spherical domains. The three-dimensional formulation of the method of finite spheres is implemented in a commercial finite element analysis program with the user-element subroutine, in order to perform a computational efficiency comparison with the standard finite element method. A series of increasingly complex three-dimensional problems is studied (1) to establish the reliability of the method of finite spheres for practical three-dimensional linear elastic static problems and (2) to assess the effectiveness of the method of finite spheres as compared to the standard finite element method. Solution times indicate that the method of finite spheres is approximately an order of magnitude slower than the standard finite element method during the computation phase. However, this is still a promising result since there are significant time savings for the method of finite spheres during the pre-processing phase, particularly in the discretization of complicated three-dimensional geometries.
by Benjamin Lai.
Ph. D.
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Skoglund, Oskar, and Daniel Samvin. "Design of slender steel members : A comparison between the reduced stress method and the effective width method." Thesis, KTH, Bro- och stålbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189029.
Повний текст джерелаАнотація:
As of now, the most common way in Sweden, to address the issue of local buckling of steelstructures is through the procedure called the effective width method. A less commonprocedure for dealing with local buckling is the reduced stress method. The benefit of thelatter method is that, when combined with finite element analysis, results in a less tediousdesign process. However, this method is often labelled as a method that results in anoverconservative design. Therefore, the purpose of this report is to compare and evaluate thereduced stress method against the effective width method and nonlinear finite elementmethod. The nonlinear FE-analyses are performed with intention of simulating the realbehaviour of the structure and serve as a reference for the other two methods. The comparisonis conducted through a series of analyses, on different steel members with various loadconfigurations and slenderness in order to include the most common cases in the constructionindustry. This report resulted in recommendations for when the reduced stress method couldbe a relevant design procedure, with emphasis on providing reliable and accurate resultscompared to FE-analyses. Furthermore, the report resulted in proposed further studies, bothregarding the improvement of the reduced stress method and other structural elements thatshould be studied. The result from the report indicates that the reduced stress method can beused when the effect of patch loading is small. Furthermore, it is recommended to obtain thecritical stresses from a linear finite element analysis rather than from hand calculations, as tonot end up with over-conservative results.I Sverige behandlas problemet med lokal buckling av stålkonstruktioner vanligtvis med hjälpav den effektiva bredd metoden, vilket är en dimensionergsmetod som återfinns i Eurocode.En ytterligare dimensionerings metod för lokal buckling som presenteras i Eurocode är denreducerade spänningsmetoden. Den senare nämnda metoden är fördelaktig då den kombinerasmed linjära finita element analyser, vilket resulterar i en mindre tidskrävandedimensioneringsprocess. Dock är metoden känd för att ofta resultera i överdimensioneradekonstruktioner, vilket bidragit till att mindre antal konstruktörer använder sig av denna metod.Syftet med denna rapport blir därmed att jämföra och utvärdera den reduceradespänningsmetoden gentemot den effektiva bredd metoden och olinjär finita element metoden.De olinjära finita element analyserna genomfördes med syfte att simulera det verkligabeteendet och för att sedan jämföra dessa resultat med de två andra metoderna. Analyser harutförts på flera stålbalkar med olika lastkombinationer och slankhet för att inkludera devanligaste fallen inom byggindustrin. Dessutom har det tagits fram några rekommendationerför användningen av metoderna och dessa är presenterade med avseende på de erhållnaresultaten. Rekommendationer för den reducerade spänningsmetoden har presenterats ochytterligare studier gällande dessa metoder och andra konstruktionselement har föreslagits. Deslutsatser som kunde dras är att den reducerade spänningsmetoden kan användas förkonstruktioner som inte påverkas i allt för stor grad av intryckning. För att ge tillförliterligaresultat så rekommenderas att kritiska spänningar erhålles från linjära finita element analyser.
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Njoku, Chinwe Christiana. "Heterogeneous mixtures for synthetic antenna substrates." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12074.
Повний текст джерелаАнотація:
Heterogeneous mixtures have the potential to be used as synthetic substrates for antenna applications giving the antenna designer new degrees of freedom to control the permittivity and/or permeability in three dimensions such as by a smooth variation of the density of the inclusions, the height of the substrate and the manufacture the whole antenna system in one process. Electromagnetic, fabrication, environmental, time and cost advantages are potential especially when combined with nano-fabrication techniques. Readily available and cheap materials such as Polyethylene and Copper can be used in creating these heterogeneous materials. These advantages have been further explained in this thesis. In this thesis, the research presented is on canonical, numerical and measurement analysis on heterogeneous mixtures that can be used as substrates for microwave applications. It is hypothesised that heterogeneous mixtures can be used to design bespoke artificial dielectric substrates for say, patch antennas. The canonical equations from published literature describing the effective permittivity, ε_eff and effective permeability, μ_eff of heterogeneous mixtures have been extensively examined and compared with each other. Several simulations of homogenous and heterogeneous media have been carried out and an extraction/inversion algorithm applied to find their ε_eff and μ_eff. Parametric studies have been presented to show how the different variables of the equations and the simulations affect the accuracy of the results. The extracted results from the inversion process showed very good agreement with the known values of the homogenous media. Numerically and canonically computed values of ε_eff and μ_eff of various heterogeneous media were shown to have good agreement. The fabrication techniques used in creating the samples used in this research were examined, along with the different measurement methods used in characterising their electromagnetic properties via simulations and measurements. The challenges faced with these measurement methods were explained including the possible sources of error. Patch antennas were used to investigate how the performance of an antenna may be affected by heterogeneous media with metallic inclusions. The performance of the patch antenna was not inhibited by the presence of the metallic inclusions in close proximity. The patch measurement was also used as a measurement technique in determining the ε_eff of the samples.
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Thein, Chung Ket. "An effective optimisation method for multifactor and reliability-related structural design problems." Thesis, University of Hull, 2011. http://hydra.hull.ac.uk/resources/hull:5338.
Повний текст джерелаАнотація:
This thesis first presents a systematic design procedure which satisfies the required strength and stiffness, and structural mass for conceptual engineering structural designs. The procedure employs a multi-objective and multi-disciplinary (MO–MD) optimisation method (multifactor optimisation of structure techniques, MOST) which is coupled with finite element analysis (FEA) as an analysis tool for seeking the optimum design. The effectiveness of the MOST technique is demonstrated in two case studies. Next, a reliability-related multi-factor optimisation method is proposed and developed, representing a combination of MOST (as a method of multi-factor optimisation) and the reliability-loading case index (RLI) (as a method of calculating the reliability index). The RLI is developed based on a well-known reliability method: the first-order reliability method (FORM). The effectiveness and robustness of the proposed methodology are demonstrated in two case studies in which the method is used to simultaneously consider multi-objective, multi-disciplinary, and multi-loading-case problems. The optimised designs meet the targeted performance criteria under various loading conditions. The results show that the attributes of the proposed optimisation methods can be used to address engineering design problems which require simultaneous consideration of multi-disciplinary problems. An important contribution of this study is the development of a conceptual MO–MD design optimisation method, in which multi-factor structural and reliability design problems can be simultaneously considered.
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Leong, Mei-kid, and 梁美潔. "Development of an effective method to tag escherichia coli chromosomalgenes by recombineering." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30430811.
Повний текст джерела
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Schafer, Ingo. "An effective cube comparison method for discrete spectral transformations of logic functions." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4147.
Повний текст джерелаАнотація:
Spectral methods have been used for many applications in digital logic design, digital signal processing and telecommunications. In digital logic design they are implemented for testing of logical networks, multiplexer-based logic synthesis, signal processing, image processing and pattern analysis. New developments of more efficient algorithms for spectral transformations (Rademacher-Walsh, Generalized Reed-Muller, Adding, Arithmetic, multiple-valued Walsh and multiple-valued Generalized Reed- Muller) their implementation and applications will be described.
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Rathod, Gaurav Dilip. "An improved effective method for generating 3D printable models from medical imaging." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/80415.
Повний текст джерелаАнотація:
Medical practitioners rely heavily on visualization of medical imaging to get a better understanding of the patient's anatomy. Most cancer treatment and surgery today are performed using medical imaging. Medical imaging is therefore of great importance to the medical industry.
Medical imaging continues to depend heavily on a series of 2D scans, resulting in a series of 2D photographs being displayed using light boxes and/or computer monitors. Today, these 2D images are increasingly combined into 3D solid models using software. These 3D models can be used for improved visualization and understanding of the problem at hand, including fabricating physical 3D models using additive manufacturing technologies.
Generating precise 3D solid models automatically from 2D scans is non-trivial. Geometric and/or topologic errors are common, and often costly manual editing is required to produce 3D solid models that sufficiently reflect the actual underlying human geometry. These errors arise from the ambiguity of converting from 2D data to 3D data, and also from inherent limitations of the .STL fileformat used in additive manufacturing.
This thesis proposes a new, robust method for automatically generating 3D models from 2D scanned data (e.g., computed tomography (CT) or magnetic resonance imaging (MRI)), where the resulting 3D solid models are specifically generated for use with additive manufacturing. This new method does not rely on complicated procedures such as contour evolution and geometric spline generation, but uses volume reconstruction instead. The advantage of this approach is that the original scan data values are kept intact longer, so that the resulting surface is more accurate. This new method is demonstrated using medical CT data of the human nasal airway system, resulting in physical 3D models fabricated via additive manufacturing.Master of Science
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Narra, Vivek Reddy, and Yashaswini Julapally. "Evaluation for an Effective Data Visualization Method in Safety Radar System Demonstrator." Thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20635.
Повний текст джерелаАнотація:
Background: Evaluation of Data Visualization methods is a major challenge within the software and other industries. With complex data and requirements, often organizations require effective visualization methods which impact business decisions and convince stakeholders. This is a similar challenge in the development of a software demonstrator for the innovative safety radar system at ABB Jokab Safety whose aim is to improve the detection reliability using multiple radar sensors and requires an effective visualization method which will satisfy all the requirements. Objectives: The main objective of this study is to explore different data visualization methods involved in illustrating the raw data and with the help of developers, and other team members feedback with reference to existing literature and filter them with respect to the system functionalities. Establish evaluation criteria with relevant metrics to perform analytic evaluations on the visualization methods to determine an effective method. Methods: A Case Study which includes a multivocal literature review, is conducted at ABB Jokab Safety. Initially, to gather information on the subject, both formal and grey literature are explored and documented to filter our appropriate data visualization methods for this system. A task-based evaluation using semi-structured interview is conducted on 14 participants to determine an effective visualization method followed by statistical analysis to derive proper validation of the findings. The Response time, Ease of understanding, Confidence and Accuracy of the visualization methods are evaluated with feedback from the participants. Results: The Multivocal literature review filtered 16 primary articles which encouraged the use of 4 data visualization methods used in the safety radar system with distinct functionalities. A coordinate transformation engine to combine the data sets was also developed for the safety radar system contributing to the overall improvement of detection reliability. The evaluation including both quantitative and qualitative results validate each other’s findings through statistical tests like Kruskal-Wallis and Bonferroni post hoc followed by narrative analysis resulting a heat temperature plot to be more effective in the visualization of the radar data from multiple sensors. Conclusions: The results from this research provide insight into how data visualization evaluation can be implemented for real-time industrial problems and furnish validation process to determine an effective data visualization method. This study helps object detection using similar radar technologies visualize their data in an effective way and provides a scientific approach for evaluating similar data visualization problems.
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du, Fresne Andrew J. "Can Audits be an Effective Method to Improve Information Governance Compliance Objectives?" University of Findlay / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=findlay1595949409362295.
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