Univ., Diss.--Gießen, 2004.

published_or_final_version / Law / Master / Master of Laws

by Susan Blumberg Liu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 112-116). / ACKNOWLEDGMENTS / ABSTRACT / DECLARATION / CHAPTER / Chapter I. --- NTRODUCTION --- p.1 / Civil Society as a Theoretical Concept / Relevance of Thesis / Organization of Thesis / Chapter II. --- CIVIL SOCIETY AND LATE IMPERIAL CHINA --- p.11 / Habermas and the Public Sphere / Habermas as Applied to the Chinese Case / Recent Debate on Civil Society in Late-Qing China / Rankin versus Wakeman / Rowe versus Wakeman / Recent Discussion on Civil Society in Contemporary China / The Question of Autonomy / Civil Society with Chinese Characteristics / Gathered Comments / Chapter III. --- THE DYNAMICS OF CIVIL SOCIETY IN THE LATE-QING ERA --- p.44 / The Emergence of a New Public / Social Class Correlation / The Constitutionalists / Women in Late-Qing China / The Press and Public Opinion / Chapter IV. --- THE MOVEMENT FOR ESTABLISHING PROVINCIAL ASSEMBLIES --- p.63 / Getting Started / The Elections / Chapter V. --- THE PROVINCIAL ASSEMBLIES COMMENCE --- p.75 / The Nature of the Assemblies / Interaction and Organization of the Assembly Members / Chapter VI. --- TWO CASE STUDIES FROM THE PROVINCIAL ASSEMBLIES --- p.83 / The Jiangsu Assembly / Organization and Preparation / The Assembly Commences / Zhang Jian: Example of the New Gentry in Late-Qing China / The Hubei Assembly / Organization and Preparation / The Assembly Commences / Chapter VII. --- CONCLUSION --- p.107 / The Fate of the Assemblies / Analysis of Findings / Lasting Implications of Civil Society in China / BIBLIOGRAPHY --- p.112

published_or_final_version / Public Administration / Master / Master of Social Sciences

L'objectif de cette thèse est d'étudier l'influence de la vitesse de déformation sur la réponse par indentation des matériaux. Les matériaux polymères thermoplastiques, notamment le Polycarbonate (PC), le Polyméthylméthacrylate (PMMA), le Polyéthylène à Haute Densité (PEHD) et le Polyamide Nylon 6.6 renforcé à 30% de fibres de verres (PA 6.6-30% GFR), ont été choisis comme matériaux d'études en raison de leur forte sensibilité à la vitesse de déformation même à température ambiante. Les deux premières parties de ce travail sont focalisées sur l'étude du comportement thermomécanique des matériaux polymères. Une étude bibliographique sur des matériaux polymères thermoplastiques, amorphes et semi-cristallins, a été effectuée afin de comprendre leur microstructure et leur mécanisme de déformation. De plus, des essais de compression simple ont été réalisés sur les matériaux d'étude à différentes vitesses de traverse constantes puis dépouillés analytiquement. Les trois derniers chapitres de cette thèse sont consacrés à la caractérisation mécanique des matériaux par indentation. En premier lieu des simulations numériques de l'essai d'indentation conique ( =70,3°) à une vitesse de pénétration constante ( = 1 µm/s) ont été effectuées à partir des paramètres de la loi de G'sell modifiée et de la loi puissance identifiés par compression. L'identification par analyse inverse des paramètres de la loi de G'sell modifiée à 7 paramètres sur des courbes pseudo-expérimentales nous a permis de confirmer la non unicité de la solution. Ainsi, nous avons effectué l'étude théorique de l'indentation sur des matériaux pseudo-expérimentaux en utilisant la loi puissance. Un nouveau concept de déformation représentative et de vitesse de déformation représentative, basé sur l'analyse du domaine de solution regroupant l'ensemble des paramètres donnant les mêmes courbes d'indentation, a été proposé. La procédure d'identification des paramètres de la loi puissance par indentation utilisant ce concept de déformation représentative et de vitesse de déformation représentative, appliquée sur un matériau pseudo-expérimental donne des résultats très satisfaisants. Sur les matériaux d'étude en revanche la méthode n'a pu révéler son potentiel puisque la loi de comportement de ces matériaux n'est pas correctement modélisée par une loi puissance sur une large plage de déformation et de vitesse de déformation. Enfin, le concept de déformation représentative et de vitesse de déformation représentative proposé dans ce travail apporte de nouveaux outils d'analyse et d'exploitation des données de l'indentation et offre des perspectives très intéressantes. / The aim of this thesis is to study the strain rate effects through materials response from indentation test. Polymeric solid material, especially Polycarbonate (PC), Polymethyl methacrylate (PMMA), High Density Polyethylene (HDPE) and Polyamide Nylon 6.6 -30% glass fiber reinforced (PA 6.6-30% GFR), were selected as study materials due to their high strain rate sensitivity even at room temperature. The first two parts of this work were focused on the study of the thermomechanical behavior of polymer materials. Bibliographical studies of thermoplastic polymer materials, amorphous and semi-crystalline, was established in order to understand their microstructure and deformation mechanism. Moreover, compression tests were performed on study materials with several crosshead speeds values then the results was exploited analytically. The last three parts were focused on mechanical characterization using Instrumented Indentation Test (IIT). Firstly, numerical simulation of a conical indentation test ( =70.3°) with a constant rate displacement ( = 1 µm/s) was established using the identified G’sell behavior parameters and the power-law parameters from compression test. Parameter identification using Inverse Analysis from numerical material shows the non-uniqueness of G’sell parameters which gives the same indentation curve. Thus, theoretical study of conical indentation test was established considering power-law model. A new concept of the representative strain and the representative strain rate, based on solution domain which associate the set of parameters leading to the same indentation curves, was proposed. Very satisfactory results was obtained when identification process using this average representative strain rate is applied to a numerical material define by a power-law model. However, this method could not show its efficiency because the mechanical behavior of the real material is not correctly modeling with a power-law at a wide range of strain and strain rate. Finally, the new concept of the representative strain and the representative strain rate proposed on this work contributes to a new investigation tools to exploit the results form IIT and provide a very interesting perspectives.

Two related bodies of work are presented, both of which aim to further the rapid development of next generation concentrating photovoltaic systems using high efficiency multi junction solar cells. They are complementary since the characterization of commercial devices and the systematic application of design principles for future designs must progress in parallel in order to accelerate iterative improvements. First addressed, is the field characterization of state of the art concentrating photovoltaic systems. Performance modeling and root cause analysis of deviations from the modeling results are critical for bringing reliable high value products to the market. Two complementary tools are presented that facilitate acceleration of the development cycle. The “Dynamic real-time I V Curve Measurement System…” provides a live picture of the current-voltage characteristics of a CPV module. This provides the user with an intuitive understanding of how module performance responds under perturbation. The “Shutter technique for noninvasive individual cell characterization in sealed concentrating photovoltaic modules,” allows the user to probe individual cell characteristics within a sealed module. This facilitates non-invasive characterization of modules that are in situ. Together, these tools were used to diagnose the wide spread failure of epoxy connections between the carrier and the emitter of bypass diodes installed in sealed commercial modules. Next, the optimization principals that are used to choose energy yield maximizing bandgap combinations for multi-junction solar cells are investigated. It is well understood that, due to differences in the solar resource in different geographical locations, this is fundamentally a local optimization problem. However, until now, a robust methodology for determining the influences of geography and atmospheric content on the ideal design point has not been developed. This analysis is presented and the influence of changing environment on the representative spectra that are used to optimize bandgap combinations is demonstrated. Calculations are confirmed with ground measurements in Ottawa, Canada and the global trends are refined for this particular location. Further, as cell designers begin to take advantage of more flexible manufacturing processes, it is critical to know if and how optimization criteria must change for solar cells with more junctions. This analysis is expanded to account for the differences between cells with up to 8 subcell bandgaps. A number of software tools were also developed for the Sunlab during this work. A multi-junction solar cell model calibration tool was developed to determine the parameters that describe each subcell. The tool fits a two diode model to temperature dependent measurements of each subcell and provides the fitting parameters so that the performance of multi-junction solar cells composed of those subcells can be modeled for real world conditions before they are put on-sun. A multi-junction bandgap optimization tool was developed to more quickly and robustly determine the ideal bandgap combinations for a set of input spectra. The optimization process outputs the current results during iteration so that they may be visualized. Finally, software tools that compute annual energy yield for input multi-junction cell parameters were developed. Both a brute force tool that computes energy harvested at each time step, and an accelerated tool that first bins time steps into discrete bins were developed. These tools will continue to be used by members of the Sunlab.

[pt] Rochas carbonáticas possuem atributos únicos que as distinguem das siliciclasticas e necessitam de diferentes métodos de estudo para caracterizar sua textura. Rochas carbonáticas são resultado de interações entre processos deposicionais químicos e biológicos. Os processos diagenéticos que formam e alteram estas rochas contribuem para o acúmulo de heterogeneidades. Devido ao alto teor de heterogeneidade, as propriedades medidas (e.g. porosidade e permeabilidade) variam com a escala de investigação e estudos com o compromisso a significância dos detalhes e representação espacial. Ampliar uma escala menor para maior, exige procedimentos que preservem a essência dos processos físicos de um nível mais detalhada para um mais grosseiro. Métodos simplificados para dimensionar propriedades não aditivas em outras escalas, tal como permeabilidade, geralmente não honram a heterogeneidade presente em sistemas complexos. Com isso a dinâmica dos fluidos em rochas complexas exige abordagens e métodos mais sofisticados. Este estudo é focado em desenvolver uma metodologia de avaliação da permeabilidade como parâmetro de escala para meios porosos heterogêneos. A permeabilidade é retro calculada ao emular o experimento de Darcy e resolver o fluxo no meio poroso utilizando uma formulação de elementos finitos para equação de Brinkman. O estudo iniciou com foco em sistemas paramétricos de células periódicas e posteriormente a duas microtomogra fia de rochas carbonáticas, do qual uma foi selecionada para um estudo de representatividade espacial. As células periódicas foram utilizadas para avaliar os efeitos da formação de canais e espaços vazios, em analogia a fraturas e vugos, assim como os efeitos da permeabilidade da matriz porosa. As amostras carbonáticas consistem de casos nos quais é possível observar a presença de uma combinação dos fenômenos estudadas. Por fim um estudo de representatividade foi conduzido segmentando uma amostra de micro-tomografia em suficientes sub-amostras que capazes de reproduzir a heterogeneidade espacial da amostra original. / [en] Carbonate rocks have unique attributes that distinguish them from siliciclastics and that require diferent methods of study to characterize their texture. Carbonates rocks are formed as a result of close interactions between biological and chemical depositional processes. The underlying diagenetic processes that form and alter these rocks contribute to a build-up of heterogeneities. Because of the high heterogeneity content measured properties (e.g. porosity and permeability) change with the scale of investigation and studies have struggle with a trade-off between significance of details and space representativeness. Extending a smaller scale to a larger requires scaling up procedures that preserves the essence of physical processes at one level to be summarized at the coarser level. Simplistic methods for scaling-up non-additive properties such as permeability generally do not honour the original heterogeneity present in complex systems. Therefore the dynamics of fluid flow in complex rocks demand more sophisticate methods and approaches. This study was focused in developing a methodology to evaluate the permeability as a scaling-up parameter for heterogeneous porous media. The permeability is back-calculated by emulating Darcy s experiment and solving the pore-scale ow using a Finite element formulation of Brinkman flow equation. The study was initially focused on parametric systems of periodic cells and later extended to two micro-tomography carbonate samples in which one has been selected for a spatial representativeness study. The parametric cells were used to evaluate the shape effects of channels and void spaces in an analogy to geological fractures and vugs as well as the permeability of the porous matrix. The micro-tomography carbonate samples consisted of a real case scenario in which, to a certain degree, could be observed a combination of the previously studied periodic cells. Finally a representativeness study was conducted segmenting the micro-tomography sample into suficiently sub-samples that would be capable of reproducing the spatial heterogeneity of the sample.

No description available.

<p>The equivalent continuum approach uses equivalent propertiesof rock mass as the input data for a continuum analysis. Thisis a common modeling method used in the field of rock mechanicsand hydrogeology. However, there are still unresolvedquestions; how can the equivalent properties be determined andis the equivalent continuum approach suitable for modeling thediscontinuous fractured rock mass.</p><p>The purpose of this paper is to establish a methodology todetermine the equivalent hydraulic and mechanical properties offractured rock masses by explicit representations of stochasticfracture systems, to investigate the scale-dependency of theproperties, and to investigate the conditions for theapplication of the equivalent continuum approach for thefractured rock masses. Geological data used for this study arefrom the site characterization of Sellafield, Cumbria, UK. Aprogram for the generation of stochastic Discrete FractureNetwork (DFN) is developed for the realization of fractureinformation and ten parent DFN models are constructed based onthe location, trace length, orientation and density offractures. Square models with the sizes varying from 0.25 m× 0.25 m to 10 m × 10 m are cut from the center ofthe each parent network to be used for the scale dependencyinvestigation. A series of the models in a parent network arerotated in 30 degrees interval to be used for investigation oftensor characteristic. The twodimensional distinct elementprogram, UDEC, was used to calculate the equivalentpermeability and compliance tensors based on generalizedDarcy’s law and general theory of anisotropic elasticity.Two criteria for the applicability of equivalent continuumapproach were established from the investigation: i) theexistence of properly defined REV (Representative ElementaryVolume) and ii) existence of the tensor in describing theconstitutive equation of fractured rock The equivalentcontinuum assumption cannot be accepted if any one of the abovetwo criteria is not met. Coefficient of variation and meanprediction error is suggested for the measures toquantitatively evaluate the errors involved in scale dependencyand tensor characteristic evaluation.</p><p>Equivalent permeability and mechanical properties (includingelastic modulus and Poisson’s ratios) determined onrealistic fracture network show that the presence of fracturehas a significant effect on the equivalent properties. Theresults of permeability, elastic moduli and Poisson's ratioshow that they narrow down with the increase of scale andmaintain constant range after a certain scales with someacceptable variation. Furthermore, Investigations of thepermeability tensor and compliance tensor in the rotated modelshow that their tensor characteristics are satisfied at acertain scale; this would indicate that the uses of theequivalent continuum approach is justified for the siteconsidered in this study.</p><p>The unique feature of the thesis is that it gives asystematic treatment of the homogenization and upscaling issuesfor the hydraulic and mechanical properties of fractured rockswith a unified approach. These developments established a firmfoundation for future application to large-scale performanceassessment of underground nuclear waste repository byequivalent continuum analysis.</p><p><b>Keywords :</b>Equivalent continuum approach, Equivalentproperty, Representative Elementary Volume (REV), DistinctElement Method, Discrete Fracture Network (DFN)</p>

Internet and social media are technologies that have increased in recent times, does it have potential for solving problems of democracy? Some researchers claim that the new technology brings new forms of communication and eases information gathering. While others believe that the technology leads to an individualization, which in turn weakens democracy. The aim of this study is to recognize causes and consequences of the Swedish citizens use of social media in the representative democracy.To achieve the purpose two tasks will be performed. The first one will be an analytical model to test two hypotheses about how the use of social media affects the individuals support for representative democracy. Second, empirical analyzes of the data from a national survey will be carried out to test the two hypotheses, the data is conducted through a statistical analysis. Based on this, an overall research question is formulated which reads: How does the individual's use of social media effect their support to representative democracy?The analyses reveals that the citizen’s use of social media has raised high expectations of vitalization and change of the representative democracy. This indicates that new technologies may reshape the political system and form new ways of political participation that strengthens democracy.