Les travaux de cette thèse s'inscrivent dans l'objectif général de fournir des recommandations sur la façon d'intégrer les effets du site dans l'évaluation probabiliste des risques sismiques, mieux connue sous le nom de PSHA, une méthodologie connue et utilisée à l'échelle mondiale pour estimer l'aléa et le risque sismiques à l'échelle régionale et locale. Nous passons donc en revue les méthodes disponibles dans la littérature pour obtenir la courbe d'aléa sismique en surface d'un site non-rocheux, en commençant par les méthodes les plus simples et plus génériques (partiellement probabiliste), jusqu'aux méthodes site-spécifiques (partiellement et entièrement probabilistes) qui nécessitent une caractérisation du site de plus en plus poussée, rarement disponible sauf cas exceptionnel comme par exemple le site test d'Euroseistest. C'est justement sur l'exemple de ce site que sont donc comparées un certain nombre de ces méthodes, ainsi qu'une nouvelle.La spécificité et la difficulté de ces études PSHA "site-spécifiques" vient du caractère non-linéaire de la réponse des sites peu rigides, ainsi que du fait que le rocher de référence contrôlant cette réponse est souvent très rigide. Les aspects "ajustement rocher dur" et "convolution" de l'aléa sismique au rocher avec la fonction d'amplification ou la fonction transfert (empirique ou numérique) d’un site font donc l'objet d'une attention particulière dans ces études comparatives. Un cadre général est présenté sur la façon de prendre en compte simultanément les caractéristiques spécifiques au site, la variabilité aléatoire complète ou réduite ("single station sigma"), les ajustements hôte-cible et le comportement linéaire / non linéaire d'un site, où nous expliquons toutes les étapes, corrections, avantages et difficultés que nous avons trouvés dans le processus et les différentes façons de les mettre en oeuvre.Cette étude comparative est divisée en deux parties: la première porte sur les méthodes non site-spécifiques et les méthodes hybrides site-spécifique (évaluation probabiliste de l'aléa au rocher et déterministe de la réponse de site), la seconde porte sur deux approches prenant en compte la convolution aléa rocher / réponse de site de façon probabiliste. Un des résultats majeurs de la première est l'augmentation de l'incertitude épistémique sur l'aléa en site meuble comparé à l'aléa au rocher, en raison du cumul des incertitudes associées à chaque étape. Un autre résultat majeur commun aux deux études est l'impact très important de la non-linéarité du sol dans les sites souples, ainsi que de la façon de les prendre en compte: la variabilité liée à l'utilisation de différents codes de simulation NL apparaît plus importante que la variabilité liée à différentes méthodes de convolution 100% probabilistes. Nous soulignons l'importance d'améliorer la manier d’inclure les effets du site dans les méthodes de l’estimation de l’aléa sismique probabiliste ou PSHA, et nous soulignons aussi l'importance d'instrumenter des sites actifs avec des sédiments meubles, comme l'Euroseistest, afin de tester et valider les modèles numériques.Finalement, on présente un résumé des résultats, des conclusions générales, de la discussion sur les principaux problèmes méthodologiques et des perspectives d'amélioration et de travail futur.Mots-clés: Effets du site, incertitude épistémique, PSHA, single station sigma, ajustements hôte-cible, effets linéaires et non linéaires, réponse de site / The overall goal of this research work is of provide recommendations on how to integrate site effects into Probabilistic Seismic Hazard Assessment, better known as PSHA, a well-known and widely used methodology. Globally used to estimate seismic hazard and risk at regional and local scales. We therefore review the methods available in the literature to obtain the seismic hazard curve at the surface of a soft soil site, starting with the simplest and most generic methods (partially probabilistic), up to the full site-specific methods (partially and fully probabilistic), requiring an excellent site-specific characterization, rarely available except exceptional cases such as the case of Euroseistest site. It is precisely on the example of this site that are compared a number of these methods, as well as a new one. And it is precisely at the Euroseistest that we performed an example of application of the different methods as well as a new one that we propose as a result of this work.The specificity and difficulty of these "site-specific" PSHA studies comes from the non-linear nature of the response of the soft sites, as well as from the fact that the reference rock controlling this response is often very rigid. The "rock to hard rock adjustment" and "convolution" aspects of the rock seismic hazard, together with the amplification function or the transfer function (empirical or numerical) of a site are therefore the subject of particular attention in these studies. comparative studies. A general framework is presented on how to simultaneously take into account the site-specific characteristics, such as the complete or reduced random variability ("single station sigma"), host-to -target adjustments and the linear / nonlinear behavior of a site, where we explain all the followed steps, the different corrections performed, the benefits and difficulties that we found in the process and the ways we sort them and discussing them when the answer was not straight forward.This comparative study is divided into two parts: the first deals with non-site-specific methods and site-specific hybrid methods (probabilistic evaluation of rock hazard and deterministic of the site response). The second deals with two approaches taking into account the convolution of rock hazard and the site response in a probabilistically way. One of the major results of the first is the increase of the epistemic uncertainty on the soft site hazard compared to the rock hazard, due to acumulation of uncertainties associated to each step. Another major common result to both studies is the very important impact of non-linearity on soft sites, as well as the complexity on how to account for them: the variability associated with the use of different non-linear simulation codes appears to be greater than the method-to-method variability associated with the two different full convolution probabilistic methods. We emphasize on the importance of improving the way in which the site effects are included into probabilistic seismic hazard methods, PSHA. And we also emphasize on the importance of instrumenting active sites with soft sediments, such as the Euroseistest, to test and validate numerical models.Finally, a summary of the results, the general conclusions, discussion of key methodological issues, and perspectives for improvement and future work are presented.Keywords: Site Effects, Epistemic Uncertainty, PSHA, single station sigma, host to target adjustments, linear and nonlinear site effects, soil site response.

Made available in DSpace on 2016-12-08T16:18:46Z (GMT). No. of bitstreams: 1 Felipe.pdf: 2736863 bytes, checksum: 2e8d61074dc45ac65af7f130eb7bd823 (MD5) Previous issue date: 2011-11-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation [Juri 2 - Dissertation] consists of the presentation and exhibition of the Project [LANDSCAPE:BORDER] which consists of a configurative practice as a discursive site of artistic investigation done as a territory consisting of a net of experiences and discursive practices, and articulates, while a discursive instance, in three stages: site experiences, docs/registries of these experiences and exhibitions (publications/talks) of the investigative process. This work [Juri 2- Dissertation] therefore consists of questions that arose between 2008 and 2010 from experiences based on the discursive site of the artistic investigation accessed through docs/registries (diagrams, articles, undone projects, etc). The dissertation/exhibition is organized in five parts: an introduction, three chapters and final considerations. The first chapter provides a close view to the process of building the Project [LANDSCAPE:BORDER] as a discursive site for of artistic investigation. The reader/public will then get to the second chapter including a discussion about site-specific contemporary practice which addresses the discursive site as a nomadic narrative whose path is articulated by the passage of the artist by contexts that are inscribed in artistic practice. On the same second chapter the Project [LANDSCAPE:BORDER] is addressed as a site placed in the intersection between the art site and other sites starting from the relationship between the generating sites and the generated sites . Third chapter derivates from the following question: how to make it the Project [LANDSCAPE:BORDER] available to the public? . It brings a discussion about building discursive exhibition sites that enable the circulation of docs/registries of experiences through artistic investigative discursive sites. Lastly final considerations presents a reflection about the practice of projects that were not intended to get to a final product shifting the attention of the work to the process, namely the life-in-the-project presented by documents / A dissertação [Banca 2 Dissertação] é uma apresentação e exposição do Projeto [PAISAGEM:FRONTEIRA], o qual é uma prática configurada como um site discursivo de investigação artística que se faz como um território constituído por uma rede de experiências e práticas discursivas, e articula-se, como instância discursiva, em três etapas: experiências pelos sites, docs/registros das experiências e exposições (publicações/conversas) do processo de investigação. O trabalho [Banca 2 Dissertação], portanto, expõe questões construídas entre os anos 2008 e 2010, a partir de experiências pelo site discursivo de investigação artística, acessadas por docs/registros (diagramas, artigos, projetos irrealizados, etc.). A dissertação/exposição organiza-se em cinco partes: uma introdução, três capítulos e considerações finais. Após passar pelo primeiro capítulo, que realiza uma aproximação ao processo de construção do Projeto [PAISAGEM:FRONTEIRA] como um site discursivo de investigação artística, o leitor/ público encontrará, no segundo capítulo, uma discussão sobre práticas contemporâneas site-specific que abordam o site discursivo como uma espécie de narrativa nômade, cujo percurso é articulado pela passagem do artista por contextos que se inscrevem na prática artística. Ainda no segundo capítulo, a partir da relação entre os Sites Geradores e os Sites Gerados que configuram o site discursivo, há uma abordagem do Projeto [PAISAGEM:FRONTEIRA] com um site posicionado na intersecção entre o campo da arte e outros campos. O terceiro capítulo, que surgiu da pergunta Como disponibilizar ao público o Projeto [PAISAGEM:FRONTEIRA]? , traz uma discussão sobre a construção de sites expositivos discursivos que possibilitem a circulação de docs/registros de experiências por sites discursivos de investigação artística. Por fim, nas Considerações Finais, há uma reflexão sobre a prática de projetos que ao não terem a preocupação de chegar a um produto final deslocam a atenção da obra para o processo, isto é, para a vida-no-projeto apresentada através de documentos

Thesis Submitted in fulfilment of the requirements for the degree MAGISTER TECHNOLOGIAE In BUSINESS INFORMATION SYSTEMS in the FACULTY OF BUSINESS at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2011 / With over a billion Internet users surfing the Web daily in search of information, buying, selling and accessing social networks, marketers focus intensively on developing websites that are appealing to both the searchers and the search engines. Millions of webpages are submitted each day for indexing to search engines. The success of a search engine lies in its ability to provide accurate search results. Search engines’ algorithms constantly evaluate websites and webpages that could violate their respective policies. For this reason some websites and webpages are subsequently blacklisted from their index. Websites are increasingly being utilised as marketing tools, which result in major competition amongst websites. Website developers strive to develop websites of high quality, which are unique and content rich as this will assist them in obtaining a high ranking from search engines. By focusing on websites of a high standard, website developers utilise search engine optimisation (SEO) strategies to earn a high search engine ranking. From time to time SEO practitioners abuse SEO techniques in order to trick the search engine algorithms, but the algorithms are programmed to identify and flag these techniques as spamdexing. Search engines do not clearly explain how they interpret keyword stuffing (one form of spamdexing) in a webpage. However, they regard spamdexing in many different ways and do not provide enough detail to clarify what crawlers take into consideration when interpreting the spamdexing status of a website. Furthermore, search engines differ in the way that they interpret spamdexing, but offer no clear quantitative evidence for the crossover point of keyword dense website text to spamdexing. Scholars have indicated different views in respect of spamdexing, characterised by different keyword density measurements in the body text of a webpage. This raised several fundamental questions that form the basis of this research. This research was carried out using triangulation in order to determine how the scholars, search engines and SEO practitioners interpret spamdexing. Five websites with varying keyword densities were designed and submitted to Google, Yahoo! and Bing. Two phases of the experiment were done and the results were recorded. During both phases almost all of the webpages, including the one with a 97.3% keyword density, were indexed. The aforementioned enabled this research to conclusively disregard the keyword stuffing issue, blacklisting and any form of penalisation. Designers are urged to rather concentrate on usability and good values behind building a website. The research explored the fundamental contribution of keywords to webpage indexing and visibility. Keywords used with or without an optimum level of measurement of richness and poorness result in website ranking and indexing. However, the focus should be on the way in which the end user would interpret the content displayed, rather than how the search engine would react towards the content. Furthermore, spamdexing is likely to scare away potential clients and end users instead of embracing them, which is why the time spent on spamdexing should rather be used to produce quality content.

abstract: Characterization of petroleum spill site source zones directly influences the selection of corrective action plans and frequently affects the success of remediation efforts. For example, simply knowing whether or not nonaqueous phase liquid (NAPL) is present, or if there is chemical storage in less hydraulically accessible regions, will influence corrective action planning. The overarching objective of this study was to assess if macroscopic source zone features can be inferred from dissolved concentration vs. time data. Laboratory-scale physical model studies were conducted for idealized sources; defined as Type-1) NAPL-impacted high permeability zones, Type-2) NAPL-impacted lower permeability zones, and Type-3) dissolved chemical matrix storage in lower permeability zones. Aquifer source release studies were conducted using two-dimensional stainless steel flow-through tanks outfitted with sampling ports for the monitoring of effluent concentrations and flow rates. An idealized NAPL mixture of key gasoline components was used to create the NAPL source zones, and dissolved sources were created using aqueous solutions having concentrations similar to water in equilibrium with the NAPL sources. The average linear velocity was controlled by pumping to be about 2 ft/d, and dissolved effluent concentrations were monitored daily. The Type-1 experiment resulted in a source signature similar to that expected for a relatively well-mixed NAPL source, with dissolved concentrations dependent on chemical solubility and initial mass fraction. The Type-2 and Type-3 experiments were conducted for 320 d and 190 d respectively. Unlike the Type-1 experiment, the concentration vs. time behavior was similar for all chemicals, for both source types. The magnitudes of the effluent concentrations varied between the Type-2 and Type-3 experiments, and were related to the hydrocarbon source mass. A fourth physical model experiment was performed to identify differences between ideal equilibrium behavior and the source concentration vs. time behavior observed in the tank experiments. Screening-level mathematical models predicted the general behavior observed in the experiments. The results of these studies suggest that dissolved concentration vs. time data can be used to distinguish between Type-1 sources in transmissive zones and Type-2 and Type-3 sources in lower permeability zones, provided that many years to decades of data are available. The results also suggest that concentration vs. time data alone will be insufficient to distinguish between NAPL and dissolved-phase storage sources in lower permeability regions. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2014

M. Tech. / Relative to other industries in South Africa and construction industries worldwide, the South African construction process generates a disproportionate number of fatalities, injuries and disease, the direct and indirect cost of which contribute to the cost of construction. Serious accidents and injuries resulting in personal injury and wrongful death occur with alarming frequency at construction sites in the U.K. The majority of accidents are not caused by careless workers but rather by failure to control. According to the Health and Safety Executive report published in 1988 out of the 90% of all construction accidents leading to death 70% could have been prevented by positive management actions and interventiion. Clients influence construction health and safety performance. Architects and design engineers often disavow responsibility for health and safety issues associated with the construction of their work. Arguably, this denial will only change if clients insist that construction health and safety is addressed on their projects. Health and safety begins with the attitude that accidents are preventable and that requirements for healthy and safe work practices must be followed. Health and safety should not be left solely under the control of the workers if injuries are to be curtailed or diminished, because the health and safety environment consists of many factors over which workers have little or no control. An underlying belief is that the majority of accidents are not caused by careless workers but by failure in controls. Although the best site management of health and safety cannot prevent all accidents, entities other than those actually performing the work do have an important role to play in enforcing proper safety standard measures : It is possible to prevent accidents from occurring. Success in health and safety has a great deal to do with people, especially those who will be responsible for ensuring that the project will be delivered safely. There is some evidence that the importance of health and safety is being realised by clients. Costs associated with worker injuries and fatalities are borne ultimately by the client and insisting that health and safety be included in design and construction considerations will prevent the occurrence of injuries and ultimately reduce the construction costs. Clients mostly set health and safety culture during the construction phase. Health and safety prequalification criteria to design approval post the design phase that shows that clients would prefer their involvement to be in specific phases. Clients do not realise that they can make significant contributions to improve health and safety performance during the early stages of a project. Clients who have to pay for construction work do not make specific cost provision for construction safety. Clients need to afford health and safety the same status as other project parameters. It is widely accepted that contractors should bear the responsibility for health and safety during the construction phase. The study found that clients regarded the construction and maintenance phases as the most important to address health and safety. Again clients do not realise the significance of placing health and safety importance in the initial phases of a project.

No description available.

The purpose of this study was to develop a Web site for a primary school and to determine the quality of the web site in comparison with the web sites of other primary schools. The specific focus of this study was to determine the promotability of the web site and to point out the advantages for the school concerned. Ms Mariaan Greyvenstein, my co-researcher, focussed on the content development and management aspects of the web sites of primary schools. The dissertations of both the researchers discuss the web site of one specific school, and for this reason some information overlaps periodically. Both of the dissertations have separate functions and each one is special in its own way. A detailed description of the development and testing of the product is given. The acquisition and evaluation of results are discussed. The researcher discusses the findings to assure the profitability of the product. / Dissertation (MA (Information Science))--University of Pretoria, 2007. / Information Science / unrestricted

Nombre de programmes ont été développés pour identifier des sites de fixation de facteurs de transcription. La plupart ne sont pas capables d’inférer des motifs composés de deux mots en autorisant une variation de leur espacement, caractéristiques des sites de fixation des sous-unités s de l’ARN polymérase (SFFS). Cette thèse vise à l’élaboration d’un algorithme prenant en compte toutes les connaissances biologiques structurelles de ces sites en vue de leur prédiction fiable. Nous présentons une nouvelle approche, SIGffRid (pour SIGma Factor Finder using R’MES to select Input Data), pour l’identification des SFFS qui compare deux génomes bactériens phylogénétiquement apparentés. La méthode analyse des paires de régions promotrices de gènes orthologues. Elle utilise la sur-représentation statistiquement dans les génomes complets comme critère de sélection des boîtes -35 et -10 potentielles. Des motifs composites conservés sont alors groupés en utilisant des paires de courtes graines, en autorisant la variabilité de l’espacement qui les sépare. Les motifs sont ensuite étendus suivant des considérations statistiques. Les plus significatifs sont retenus. Cet algorithme a été applique´ avec succès à la paire de génomes bactériens apparentés de Streptomyces coelicolor A3(2) et Streptomyces avermitilis. Nous démontrons que notre approche, combinant des critères statistiques et biologiques, parvient à prédire des SFFS, et abordons les améliorations envisagées. / Many programs have been developed to identify transcription factor binding sites. Most of them are not able to infer two-word motifs with variable spacer lengths, characteristics of RNA polymerase Sigma (s) Factor Binding Sites (SFBSs). The aim of this thesis is to design an algorithm taking into account the biological structural observations about these sites, in order to their relevant prediction. We describe a new approach, SIGffRid (SIGma Factor binding sites Finder using R’MES to select Input Data), to identify SFBSs by comparing two related bacterial genomes. The method performs a simultaneous analysis of pairs of promoter regions of orthologous genes. SIGffRid uses a prior identification of over-represented patterns in whole genomes as selection criteria for potential -35 and -10 boxes. These patterns are then grouped using pairs of short seeds, allowing a variable-length spacer between them. This is followed by motif extension guided by statistical considerations. Finally, statitically feasible and relevant motifs are selected. We applied our method to the pair of related bacterial genomes of Streptomyces coelicolor A3(2) and Streptomyces avermitilis. We demonstrate that our approach combining statistical and biological criteria was successful to predict SFBSs, and envisage ameliorations.

Mechanistically and structurally chloroperoxidase (CPO) occupies a unique niche among heme containing enzymes. Chloroperoxidase catalyzes a broad range of reactions, such as oxidation of organic substrates, dismutation of hydrogen peroxide, and mono-oxygenation of organic molecules. To expand the synthetic utility of CPO and to appreciate the important interactions that lead to CPO’s exceptional properties, a site-directed mutagenesis study was undertaken. Recombinant CPO and CPO mutants were heterologously expressed in Aspergillus niger. The overall protein structure was almost the same as that of wild type CPO, as determined by UV-vis, NMR and CD spectroscopies. Phenylalanine103, which was proposed to regulate substrate access to the active site by restricting the size of substrates and to control CPO’s enantioselectivity, was mutated to Ala. The ligand binding affinity and most importantly the catalytic activity of F103A was dramatically different from wild type CPO. The mutation essentially eliminated the chlorination and dismutation activities but enhanced, 4-10 fold, the epoxidation, peroxidation, and N-demethylation activities. As expected, the F103A mutant displayed dramatically improved epoxidation activity for larger, more branched styrene derivatives. Furthermore, F103A showed a distinctive enantioselectivity profile: losing enantioselectivity to styrene and cis-β-methylstyrene; having a different configuration preference on α-methylstyrene; showing higher enatioselectivites and conversion rates on larger, more branched substrates. Our results show that F103 acts as a switch box that controls the catalytic activity, substrate specificity, and product enantioselectivity of CPO. Given that no other mutant of CPO has displayed distinct properties, the results with F103A are dramatic. The diverse catalytic activity of CPO has long been attributed to the presence of the proximal thiolate ligand. Surprisingly, a recent report on a C29H mutant suggested otherwise. A new CPO triple mutant C29H/C79H/C87H was prepared, in which all the cysteines were replaced by histidine to eliminate the possibility of cysteine coordinating to the heme. No active form protein was isolated, although, successful transformation and transcription was confirmed. The result suggests that Cys79 and Cys87 are critical to maintaining the structural scaffold of CPO. In vitro biodegradation of nanotubes by CPO were examined by scanning electron microscope method, but little oxidation was observed.

A new generation of Titanium based catalysts for ethylene polymerization has been developed through the Surface Organometallic Chemistry (SOMC) methodology using a novel type of silica support having a 3D fibrous morphology, KCC-1. The first type of Tibased catalyst was obtained by reacting isolated silanol surface groups, ≡SiOH of KCC-1 (dehydroxylated at 700 ⁰C under high vacuum, 10-5 bar) with titanium (IV) tetraneopentyl, Ti(CH2tBu)4 to produce [(≡SiO)Ti(CH2tBu)3]. The second type of Ti-based catalyst was generated by using an Al-modified KCC-1. The peculiarity of this support is due to the presence of tetra-coordinated aluminum-bound hydroxyl group, [(≡Si-O-Si≡)(≡SiO)2Al- OH] that can be used as a Lewis Acid anchor sites and generate new catalytic properties. The well-defined [(≡Si-O-Si≡)(≡SiO)2Al-OH] was obtained by reacting diisopropylaluminum hydride with KCC treated at 700 °C followed by a thermal treatment at 400 °C and oxidation with N2O. IR spectra of pyridine adsorbed on the Al sites show that these were strong Lewis acid sites (constituting 80% of the total Al sites). Thus, the highly electrophilic support surface was used to create a single well-defined surface organo-titanium fragment [(≡Si–O–Si≡)(≡Si–O–)2Al–O–Ti(CH2tBu)3] by the reaction of the surface [(≡Si–O–Si≡)(≡Si–O)2Al–OH]) groups with Ti(CH2-tBu)4 at room temperature for 4 h in dry pentane. The performance of each Ti-supported catalyst assessed for ethylene polymerization. It was found that Al-modified support (highly electrophilic) provide better activity compared to the unmodified one. Indeed, the productivity of the catalyst [(≡Si–O– Si≡)(≡Si–O–)2Al–O–Ti(CH2tBu)3] was found to be 67.8 g of PE/ 1mmol Ti/ 1h with molecular weight of 3208408 g/mol; polydispersity was found to be 2.3, and (HDPE) high-density polyethylene was obtained. In contrast, [(≡SiO)Ti(CH2tBu)3] (unmodified one) produces lower molecular weight polymer 989843 g/mol, higher polydispersity (PD) 6.7 and low-density polyethylene (LDPE) productivity was found to be 14.670 g PE/1mmol Ti /1h. These results demonstrate that modification of the oxide ligands on silica through a generation of Al Lewis acid site opens up new catalytic properties, markedly enhancing the catalytic performance of supported organotitanium species. We also demonstrate how the silica mesostructure (2D vs 3D ) affects the catalytic activity in ethylene polymerization. While SBA15 (2D) could limit the accessibility of the active sites resulting in lower yield. In contrast, KCC-1 (3D) are more active in ethylene polymerization, because the active sites reside on the external surface are fully accessible to the substrate.