111 |
An experimental study and finite analysis of punching shear failure in steel fibre-reinforced concrete ground-suspended floor slabsLabib, Wafa Abdelmajeed January 2008 (has links)
The present research is concerned with investigating the structural effect of using steel fibre-reinforcement on the punching shear behaviour of ground-suspended slabs with internal columns. The main objectives of this research were to develop a constitutive model for steel fibre-reinforcement (SFRC), to study experimentally the punching shear behaviour of SFRC with no longitudinal reinforcement and to develop a finite element model that can accurately predict the behaviour of SFRC slabs subjected to punching shear. In this respect, a literature review of the work undertaken by previous researchers on punching shear behaviour of concrete slabs is presented. After that, a constitutive model for SFRC was developed. This is followed by a preliminary finite element analysis (FEA) and experimental study of SFRC slabs. Finally, a finite element model was developed. The literature review revealed that little work has been carried out to study the effect of fibre-reinforcement on the punching shear capacity of concrete slabs. Furthermore, structures, hence a thorough investigation in this area was mandatory. A constitutive model for SFRC in post-cracking stage was developed. This enables one to estimate the tension stiffening behaviour of SFRC based on a simple beam bending test and a statistical model developed in this research, this constitutive model was used later on in the modelling of the SFRC slabs using FEA. In the preliminary FEA, sufficient information for the size and the design of test specimens that were used in the experimental programme was produced. In the experimental study, eight steel fibre-reinforced concrete slab-column connection specimens were tested. The variables of the test specimens include the concrete compressive strength, fibre dosage and fibre aspect-ration.
|
112 |
Solar energy in construction : an assessment of solar wall thermal performance in EuropeWormald, Roy January 1998 (has links)
No description available.
|
113 |
Procuring the urban house in paradiseSmith, Charles Roy January 2001 (has links)
The ambition of the thesis was to consider the performance of urban dwellings, and more specifically to develop a series of benchmarked criteria that holistically define the performance of an urban dwelling throughout its lifecycle, then to create an assessment tool that extends the scope of existing environmental evaluation models. The benchmarks for each of the criteria define the quantitative and qualitative performance values of firstly, a dwelling built to current regulation standards, secondly a European comparison, and thirdly one of the drawn studies undertaken as part of the research methodology; finally the performance of the 'urban house in paradise' is proposed, based upon advances to the above. These benchmarks provide a generic framework that describes the integrated performance of adwelling. The tool advances existing assessment models by responding to their identified shortcomings, which includes taking account of the interrelation between criteria and evolves significance weightings in terms of the relative priority of the criteria to each other. By attempting to resolve the linkages between the criteria, the tool as developed will model how these interrelated benchmarks effect each other within agiven project, so that a holistic set of vaJues, the ideal balance of priorities, can be developed. This will enable a designer to determine the best overall balance of a dwelling's performance, taking account of the identified relative significance of each of the criteria, to bring the sustainability of a project as close as possible to the idealo f the 'urban house in paradise'.S uch a development provides an advance upon existing techniques in defining and assessing the ecological performance of adwelling. The contributions to knowledge made by this thesis are primarily in increasing the depth and scope of assessing the performance, and in particular the environmental performance, of dwellings. The field of criteria in existing environmental assessment methods is extended to include not only a broader, and therefore more holistic range than any other environmental assessment model, but also those relevant to socio-economic areas of sustainability. Prioritisation and interrelation between the individual criteria was developed in the assessment tool's methodology: interrelation is crucial, as sustainability demands a holistic view. Assessment and prioritisation methods are based on the philosophy of Deep Ecology, and not an anthropocentric orientation, therefore potentially creating a radical reappraisal of the criteria considered important in other assessment models. The prioritisation extends between fields, in search of most significant criteria within a holistic view and has identified, within the boundaries of what is technically feasible, the criteria that can contribute most to achieving more ecologically sustainable dwelling in a Deep Ecological sense.
|
114 |
Investigation of a novel multifunctional roof panel for hybrid photovoltaic/thermal/daylight application in atrium and large green houseYu, Xu January 2015 (has links)
Daylight is an energy efficient solution for illumination and visual comfort in buildings. However, successful daylight design requires effective daylight control technology to eliminate the negative impact such as overheating, unbalanced indoor daylight distribution and glare. With this mind, the current thesis presents a novel multifunctional roof panel which might be applied in atrium and large green house. The working principle of the panel is based on the non-imaging low-concentration solar collector: dielectric Compound Parabolic Concentrator (CPC). Detailed study on the dielectric CPC has found that there would be some light escaping from side wall of CPC when the incident light is beyond CPC acceptance angle, which could actually be used for indoor daylight provision; while the incident light concentrated on the base of CPC could be used for concentrating PV application. Thus a dielectric CPC panel which consists of several trough dielectric CPC rods is designed and manufactured, its function of hybrid PV/Daylight is investigated through PHOTOPIA simulation and outdoor testing, both simulated and measured results showed that under sunny condition, only 10-15% of light could be transmitted through the panel in cooling season, and the rest of the light is used for concentrating PV application; while light transmittance of about 40-60% is achievable in winter period, when daylight is desired. Additionally, constant light transmittance of about 40% is achievable under overcast sky. The above figures could verify the seasonal daylight control ability of the panel. On the other hand, for the designed panel, the rejected heat on PV could still flow into the building. As a result, a PV/Thermal system is designed to remove the rejected heat on PV cell and reutilize it for thermal application such as food drying. The design parameter such as approach velocity, pitch distance, and perforation porosity are numerically investigated by CFD simulation. The prototype of the system is built and measured under solar simulator and real sky. Both simulated and measurement results showed that the heat recovery efficiency could be 40-80% depending on different geometries and approach velocities; and little amount of rejected heat could transfer from the PV cell to the building interior. The hybrid PV/Thermal application seems to be achievable. Lastly, the energy and economic performance for the EW-orientated dielectric CPC panel is investigated using new proposed concept of “inner south projection angle” and its correlation with the CPC optical performance, the building energy simulation software EnergyPlus and its weather data are also employed. An example case on an educational building with a central atrium in Nottingham shows that: compared to the conventional double glazing window, there is 55% increase in useful daylight illuminance (500-2000lux) percentage; 81.5% reduction in window solar heat gain in cooling season and only 10.78% reduction in window solar heat gain in heating season; there is also a power generation of 290.65W/m2 from PV cells; and the estimated payback period is less than 5 years. Therefore, the proposed multifunctional roof panel for PV/Thermal/Daylight application could comprehensively utilise the solar energy and provide comfort thermal and visual indoor environment.
|
115 |
A performance evaluation of mainstream timber framed and traditional masonry housing in the UKBailey, David January 2016 (has links)
Within the UK traditional masonry construction techniques are struggling to deliver the quantity and ecological quality of housing required by an ever increasing UK population. This research employs a case study review of a mainstream mixed timber frame and masonry housing development - Green Street, in order to explore the ecological viability of timber prefabrication as an alternative to the established masonry construction methods currently employed in the majority of British housing. Four houses of each construction type in the Green Street development were outfitted with a number of environmental monitoring sensors for continuous monitoring. In addition the study incorporates fabric testing in the form of air permeability testing, Co-heating analysis, thermography, and a life cycle analysis. Building Use Survey, project management and design team interviews and an industry questionnaire form the final part of the evaluation protocol. The study revealed that heating the timber dwellings ultimately required less energy per degree difference between inside and outside temperatures. During the summer the timber housing displays a greater diurnal temperature swing, while on average the temperature remains consistently lower than the masonry housing. The masonry housing was found to be both more air tight and exhibiting a lower heat loss coefficient, despite that, the performance gap between design and reality for space heating is less in the timber prefabricated housing. The life cycle analysis revealed that the timber walls have a lower impact on climate change. BUS methodology results found that construction type had little to no impact on occupants. The design team review highlighted the need for a greater level of prefabrication in timber housing to increase precision and work around a serious skills shortage. An industry questionnaire suggested that timber construction in the UK can often suffer from poor construction practice, predicated by a gap in specialized knowledge. The research concludes that in this instance, the timber prefabrication technique produced dwellings that perform ecologically on par with their masonry counterparts. In answering the research question, the evidence suggests that at this stage the technique would be better employed on a case by case basis and supported by specialists in timber fabrication, rather than implemented as a blanket alternative for existing masonry construction. Already a number of insights from this research have filtered into industry practice and will continue to better inform both industrial and academic partners in their decisions regarding the use of timber prefabrication in mainstream UK housing.
|
116 |
Prenatal Morphine Exposure Differentially Alters TH-Immunoreactivity in the Stress-Sensitive Brain Circuitry of Adult Male and Female RatsVathy, Ilona, He, Huang Jun, Iodice, Mary, Hnatczuk, Oksana C., Rimanóczy, Agnes 01 February 2000 (has links)
Previously, we demonstrated that exposure to morphine during gestation increases hypothalamic norepinephrine (NE) content and turnover rate in adult male rats and decreases these measures in adult females. To investigate the basis of these alterations, the present study examined the effects of prenatal exposure to morphine on tyrosine hydroxylase immunoreactivity (TH-IR) in the brains of adult male and female progeny. In male rats, prenatal morphine exposure significantly increased the density of TH-IR in cells and fibers in the caudal paraventricular nucleus of the hypothalamus (PVN) and locus coeruleus (LC), but had no effects in the lateral hypothalamus (LH). In female rats that were ovariectomized (OVX), prenatal morphine exposure significantly decreased the density of TH-IR in cells and fibers in the LC. Interestingly, an injection of estrogen in OVX control females reduced the mean optical density of TH-IR in the LC, but it was ineffective in drug-exposed females in the same brain region. Estrogen injections also reduced the mean optical density of TH-IR in the LH but not in the PVN of females, regardless of prenatal drug exposure. Thus, the present study suggests that prenatal morphine exposure induces long-term, sex-specific alterations in TH-IR in the PVN and LC of adult progeny.
|
117 |
Células fotovoltaicas orgânicas do tipo heterojunção de volume fabricadas a partir de solventes não halogenados / Organic photovoltaic cells bulk-heterojunction manufactured from non-halogenated solventsSousa, Livia Maria de Castro 03 August 2018 (has links)
A crescente demanda energética mundial vem estimulando pesquisas em novas fontes de energia limpa e renovável e de baixo custo. Nesse contexto, as células solares orgânicas (fotovoltaicos orgânicos – OPVs) destacam-se como uma alternativa promissora no campo dos fotovoltaicos. Por serem fabricadas a partir de soluções eletrônicas, sua fabricação se dá deposição sobre substratos rígidos ou flexíveis, e com isso, também por técnicas de impressão. Muitas moléculas poliméricas têm mostrados excelentes resultados, porém o desempenho das células dependem também da morfologia do filme ultrafino da camada ativa, a qual depende do processamento e sobretudo da atividade dos solventes orgânicos. Até o momento, a maioria dos solventes usados para a fabricação das OPVs de alto desempenho é da classe dos halogenados, como por exemplo, o clorobenzeno e o 1,2-diclorobenzeno. Esses solventes, além de exibirem alto custo de produção, apresentam toxicidade relativamente alta, com impactos adversos à saúde humana e ao meio ambiente. Visto que a tecnologia dos OPVs está próxima de sua comercialização, a procura por solventes alternativos de baixa toxicidade coloca-se como um desafio a essa área. Neste trabalho, identificou-se por meio dos parâmetros de solubilidade de Hansen, um solvente da classe dos não halogenados e não aromáticos com baixa toxicidade ao ser humano e ambientalmente amigável para ser aplicado como solvente de processamento de células solares orgânicas do tipo heterojunção de volume (BHJ). Para isso, os possíveis solventes foram avaliados segundo os parâmetros de solubilidade de Hansen para os polímeros, P3HT e PTB7-Th, e para as moléculas PC61BM e PC71BM, levando em consideração os critérios de riscos com base na ficha de segurança de produtos químicos. Desse modo, a ciclohexanona foi selecionada por conter as características desejadas para o estudo proposto no presente trabalho. As soluções de P3HT e de PTB7- Th em ciclohexanona foram avaliadas quanto à influência da temperatura das soluções na conformação dos polímeros, a partir da técnica de termocromismo. Os resultados revelam necessidade de aquecimento para que haja uma conformação menos agregada tanto do P3HT quanto do PTB7-Th em solução de ciclohexanona. Os filmes de P3HT:PC61BM e PTB7-Th:PC71BM foram depositados pela técnica de spin-coating sobre substratos de vidro e estudos sobre sua morfologia foram realizados por técnicas de imagens de microscopia óptica, AFM e medidas de absorção pela técnica UV-vis, e correlacionadas ao desempenho das células fabricadas. Os resultados obtidos foram promissores uma vez que nesse trabalho conseguimos células de até 5,5 % de eficiência. / The growing global demand for energy has been stimulating research into new sources of clean and renewable energy and low cost. In this context, organic solar cells (organic photovoltaic - OPVs) stand out as a promising alternative in the field of photovoltaics. Because they are manufactured from electronic solutions, it can be deposited on rigid or flexible substrates, facilitating their production by printing techniques. Many polymer molecules have shown excellent results, but the performance of the cells also depends on the morphology of the ultrathin film of the active layer, which depends on the processing and above all the activity of the organic solvents. To date, most of the solvents used in the manufacture of high-performance OPVs belong to the halogen class, for example chlorobenzene and 1,2-dichlorobenzene. These solvents, in addition to exhibiting high cost of production, have relatively high toxicity, with adverse impacts on human health and the environment. Since the technology of OPVs is close to commercialization, the search for low-toxicity alternative solvents poses a challenge in this area. In this work, Hansen\'s solubility parameters were used to identify solvents of non-halogenated and non-aromatic class with low toxicity to humans and environmentally friendly, as substitutes of traditional solvents used to process organic solar cells (BHJ). For this, several solvents were evaluated according to the Hansen solubility parameters for the polymers, P3HT and PTB7-Th, and for the molecules PC61BM and PC71BM, taking into account the risk criteria based on the chemical safety data sheet. The solutions of P3HT and PTB7-Th in cyclohexanone were evaluated taking into account the influence of the temperature of the solutions on the conformation of the polymers, using the thermochromic technique. The solutions of P3HT and PTB7-Th in cyclohexanone were evaluated taking into account the influence of the temperature of the solutions on the conformation of the polymers, using the thermochromic technique. The resulted morphology was then correlated with the devices performance. The results obtained were promising since in this work we obtained cells of up to 5.5% efficiency.
|
118 |
Anne-Thérèse de Lambert und Sophie von La Roche als Innovatorinnen der weiblichen Erziehungsdebatte im 17. und 18. JahrhundertEisele, Katharina Eva January 2008 (has links)
France played a leading role in the European Enlightenment, influencing other European countries in their thinking and development of philosophical ideas based on the emerging ideals of liberté, égalité and fraternité. Among the many topics alive in intellectual circles at the time, a debate about the education of females peaked in the 18th century, and it is not surprising that it was a Frenchman, François Fénelon, who drew attention first through his Traité de l'éducation des filles (1687) to the lack of education for females. His countrywoman Madame de Lambert extended his argument in her Avis d’une mère à sa fille (1688-1692, published 1728), a lengthy essay addressed to her daughter justifying the importance and describing the nature of female education. A half century later in Germany, Sophie von La Roche published her Briefe an Lina: Ein Buch für junge Frauenzimmer[,] die ihr Herz und ihren Verstand bilden wollen in her weekly paper Pomona für Teutschlands Töchter (1783/84). In these letters, collected and published in book form in 1807, she described the principles of a program of education for women which would lead to a happy life. Both of these female writers were exceptions in their time and fought to establish the position of women as educated and valued members of society. This thesis contextualizes and examines their writings to answer the question to what degree they contributed to a progressive step in the education of women at the time and the cultivation of educated and critical thinking in the next female generation.
Hippolyte Taine’s sociological method assumes that literature can be analyzed through its author’s life on the basis of the three key concepts, race, milieu, and moment. After applying these concepts to the life of Madame de Lambert and Sophie von La Roche through historical background and sociological analysis, a close textual examination of the two central texts proceeds with these points of emphasis in each woman’s case: biographical background and social role determination (Frauenbild und Bestimmung der Frau); accommodation to the notion of ‘pleasing’ society, the males especially, and instilling happiness in others and themselves (Gefallen und Glück); and the education and erudition of women (Bildung und Gelehrsamkeit). Their contributions to these areas of active life and intellectual debate illustrate to some extent a personal adaptation to the conventions and standards of the era, but more importantly, beyond that, a breakout from traditional ideas and practices. In sum, Madame de Lambert is seen as a pioneer in the philosophical evaluation of the intellectual strength of women, and Sophie von La Roche, as a German counterpart with an emphasis on their practical enlightened education. The comparative analysis also reveals important sociological differences between Germany and France in the 18th century with regard to the subject of female education.
|
119 |
Anne-Thérèse de Lambert und Sophie von La Roche als Innovatorinnen der weiblichen Erziehungsdebatte im 17. und 18. JahrhundertEisele, Katharina Eva January 2008 (has links)
France played a leading role in the European Enlightenment, influencing other European countries in their thinking and development of philosophical ideas based on the emerging ideals of liberté, égalité and fraternité. Among the many topics alive in intellectual circles at the time, a debate about the education of females peaked in the 18th century, and it is not surprising that it was a Frenchman, François Fénelon, who drew attention first through his Traité de l'éducation des filles (1687) to the lack of education for females. His countrywoman Madame de Lambert extended his argument in her Avis d’une mère à sa fille (1688-1692, published 1728), a lengthy essay addressed to her daughter justifying the importance and describing the nature of female education. A half century later in Germany, Sophie von La Roche published her Briefe an Lina: Ein Buch für junge Frauenzimmer[,] die ihr Herz und ihren Verstand bilden wollen in her weekly paper Pomona für Teutschlands Töchter (1783/84). In these letters, collected and published in book form in 1807, she described the principles of a program of education for women which would lead to a happy life. Both of these female writers were exceptions in their time and fought to establish the position of women as educated and valued members of society. This thesis contextualizes and examines their writings to answer the question to what degree they contributed to a progressive step in the education of women at the time and the cultivation of educated and critical thinking in the next female generation.
Hippolyte Taine’s sociological method assumes that literature can be analyzed through its author’s life on the basis of the three key concepts, race, milieu, and moment. After applying these concepts to the life of Madame de Lambert and Sophie von La Roche through historical background and sociological analysis, a close textual examination of the two central texts proceeds with these points of emphasis in each woman’s case: biographical background and social role determination (Frauenbild und Bestimmung der Frau); accommodation to the notion of ‘pleasing’ society, the males especially, and instilling happiness in others and themselves (Gefallen und Glück); and the education and erudition of women (Bildung und Gelehrsamkeit). Their contributions to these areas of active life and intellectual debate illustrate to some extent a personal adaptation to the conventions and standards of the era, but more importantly, beyond that, a breakout from traditional ideas and practices. In sum, Madame de Lambert is seen as a pioneer in the philosophical evaluation of the intellectual strength of women, and Sophie von La Roche, as a German counterpart with an emphasis on their practical enlightened education. The comparative analysis also reveals important sociological differences between Germany and France in the 18th century with regard to the subject of female education.
|
120 |
Thermochronometric investigation of the Paleozoic stratigraphic and thermal evolution of the Western Desert, EgyptRhatigan, Caleb Hayes 01 November 2013 (has links)
The northeast African continental margin of the Western Desert of Egypt is host to a complexly deformed series of Phanerozoic basins. Substantial sedimentary deposition (~5 km) and basin formation resulted from regional deformation due to continental collision and repeated rifting and inversion cycles. Limited sedimentary exposure and exploration has prevented elucidation of Phanerozoic basin evolution, particularly in the Paleozoic. Previous studies of the region have largely relied upon sedimentary analysis, gravity, and 2D/3D seismic data. This study, in contrast, has employed extensive use of detrital zircon (U-Th)/He thermochronology (n=1004) from 17 wells in conjunction with 3D seismic, well log correlation, and heat flow data to elucidate a spatiotemporally comprehensive tectonic and stratigraphic model.
The detrital zircon thermochronometric data provides new evidence that the lower Paleozoic, Carboniferous, and Mesozoic stratigraphic sequences of the Western Desert represent thermally distinct, tectonically controlled sequences with independent thermal evolutions. The lower Paleozoic sequence has been partially thermally reset, reaching temperatures of ~140-170 ̊C. Partial resetting is noted throughout the region and reached its thermal maximum in the Permo-Triassic, synchronous with onset of Neotethyan rifting. The Carboniferous sequence has not been thermally reset, with exposure to temperatures no greater than ~140 ̊C and reaching thermal maximum presently. Carboniferous (U-Th)/He ages have dominant input from short-lag-time zircons (exhumation to deposition) and indicate the stratigraphic sequence was proximally sourced. The proximal sourcing is likely from transmitted stress and fault reactivation in Egypt during the Hercynian Orogeny that caused fault block exhumation and erosional unroofing. Sediment was shed from uplifted fault blocks that formed the eastern boundary of the Carboniferous sequence. The Mesozoic sequence has not been thermally reset, reaching temperatures no greater than ~120 ̊C and presently reaching thermal maximum.
Localized areas with stacking of lower Paleozoic, Carboniferous, and Mesozoic sequences likely bury the lower Paleozoic to abnormally deep depths (~7 km) and elevated temperatures of ~200 ̊C. Evidence from faulting relationships, basin controlling structures, and heat flow data indicate that N-S trending basement structures may define a region of crustal transition between the Archean-Paleoproterozoic Saharan Metacraton and the juvenile Arabian-Nubian Shield. / text
|
Page generated in 0.0274 seconds