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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A STUDY OF THE ELIMINATION OF THE INFINITE POLE IN THE POLE-DIPOLE ELECTRICAL RESISTIVITY ARRAY

2015 December 1900 (has links)
The pole-dipole (PD) electrical resistivity array is used as part of a geophysical technique, which can be used in exploration for mineral, geothermal and hydrological resources. Furthermore, it can be used in archaeological investigations. The PD array is useful in obtaining large depths of investigation, but the array requires one pole to be planted at a greater distance from the other electrodes. Placing the infinite pole is time consuming and costly, especially in rough terrains. It can also be a liability in populated areas. Previous data inversion software assumes the infinite pole to be planted at infinity. Therefore, the field data collected has to mimic the assumptions of the inversion software. Some recent inversion programs use all 4-electrode positions for data inversion. In this case, is a good approximation of infinity for the infinite pole still necessary? Is the depth of investigation still the same or relevant with a non-infinite, infinite pole? Is the resolution of the cross-sections retained? To answer the above questions a Generalized Electrode Array (GEA) 1 dimensional (1D) inversion program is used. Different sets of field data were collected with non-infinite pole (NIP) PD arrays; these arrays are set up as PD arrays with an infinite pole planted relatively close to or on the survey lines itself. A COMSOL finite element model were modelled with varying infinite pole distances to identify the distance required for the retention of the depth of investigation and resolution of the PD array. Modelling from GEA shows the NIP distances do not affect the 1D inversion accuracy of the resistivity nor the layer thickness. The field data indicates that it is necessary to have an infinite pole, but the distance to the infinite pole can be substantially less than 10 times the array length, which is the usual rule of thumb for infinite pole placement. With 3 dimensional (3D) COMSOL modelling results, it indicates a minimum pole distance to be 2.5-array length to retain the depth of investigation and precision of the inverted sections of the PD array.
2

Noise Characerization For Proposed UCF Phyiscal Science Building Sites.

Martinez, Jorge 01 January 2006 (has links)
Today's Advance Technology Facilities require low noise levels and increased noise monitoring. Ambient noise can interfere with the accuracy and precision of experiments and manufacturing processes. Therefore preconstruction site surveys are needed to develop strategies for mitigating noise. Vibration and low frequency electromagnetic fields are particularly detrimental for sensitive instruments, and they are also difficult to mitigate. However a large part of these costs can be avoided or minimized if a quiet building site is selected in the first place. Accelerometers and gauss meters combined with a computer for acquisition and analysis provide a low cost method of evaluating noise levels at proposed building sites. This work examines low frequency vibration and electromagnetic fields at two proposed sites for the planned Physical Science Building at the University of Central Florida.
3

Full Scale Evaluation of Organic Soil Mixing

Costello, Kelly 16 March 2016 (has links)
Soil mixing is a procedure that has proven to be effective for loose or soft compressible soils. The method stabilizes the soil in-place using specialized augers, tillers, or paddles that inject grout or dry cementitious powders as part of the mixing process. The Federal Highway Administration design manual for soil mixing helps to estimate the required amount of cementitious binder to produce a target design strength. However, it is biased towards inorganic soils and only mentions caution when confronting organic soils which usually come with a high water table, moisture content and void volume. The Swedish Deep Stabilization Research Centre cited studies with highly organic soils in regards to soil mixing and suggested that organic soils may need to reach a ‘threshold’ of cement content before strength gain can occur. The University of South Florida also conducted a study on highly organic soils and was able to confirm this concept. USF also proposed a threshold selection curve based on the organic content. This thesis extends this concept to the bench scale testing of multiple full scale field studies. This thesis will conclude with the presentation of new threshold curves based on the new data from the added field case studies. Given that there were variable binders and soil types used in the data analyzed, these threshold curves are dependent upon soil type and binder type, thus expanding upon the curve previously suggested.
4

Discours épilinguistique et urbanité : Hanoï, une ville sociolinguistiquement singulière ? / Epilinguistic discourse and urbanity : Hanoi, sociolinguistically a singular city ?

Đặng, Thị Thanh Thuý 05 May 2015 (has links)
La recherche en question, à inscrire en sociolinguistique urbaine s’attache à étudier les liens tissés entre l’espace, la langue et l’identité dans le contexte de la culture urbaine de Hanoï et ce, au travers des discours des jeunes habitant la ville. Cette démarche fondée sur enquêtes de terrain (entretiens semi-directifs, questionnaire, locuteurs masqués) permet de rendre compte du « poids urbain » de Hanoï dans différents types de pratiques (sociolinguistiques, culturelles, socio-spatiales, identitaires…) des habitants de la ville. La recherche tente aussi de montrer comment les discours épilinguistiques contribuent à la production des normes substandard et à la normalisation de l’espace socio-langagier duparler urbain hanoïen. / The present research, in the field of urban sociolinguistics, studies the links created between space, language and identity in the discourses of young urban residents. Based on field surveys (semidirective interviews, questionnaires, hidden speakers), this approach Hanoï's urban weight to show in several kinds of urban residents practices (sociolinguistical, cultural, socio-spatial, identity-related practices…). This research is also an attempt to show how epilinguistical discourses contribute to the production of substandart norms and to the standardization of the sociolinguistic space of Hanoï's urbanspeeches.
5

Identification and molecular characterization of three genetic variants of Grapevine leafroll-associated virus 3 (GLRaV-3) from South African vineyards and their spread in local vineyards

Jooste, Anna Elizabeth Catharina 03 1900 (has links)
Thesis (PhD (Genetics))--University of Stellenbosch, 2011. / Includes bibliography / ENGLISH ABSTRACT: Grapevine diseases, in particular virus and virus-like diseases, are threatening grapevine industries worldwide; also in South Africa. Grapevine leafroll (GLR) is one of the most important diseases of grapevines, occurring in all grape-producing countries worldwide. Grapevine leafroll-associated virus 3 (GLRaV-3) is known to be closely associated with GLR disease and occurs commonly in South African vineyards. In this study three genetic variants of GLRaV-3 were identified in vineyards of the Western Cape, South Africaby single strand conformation polymorphism (SSCP) profiles generated from a region amplified in ORF5. A specific SSCP profile could be assigned to each variant group and these wereconfirmed by sequencing of the ORF5 regions.These results demonstrated that SSCP analysis on this region in ORF5 provides a fast and reliable indication of the GLRaV-3 variant status of a plant, which in many instances showed mixed infections. The full genome sequence of one representative of each variant group i.e. isolates 621 (group I), 623 (group II) and PL-20 (group III), was determined by sequencing overlapping cloned fragments of these isolates. The sequences of genomic 5’ ends of these isolates were determined by RLM-RACE. Sequence alignment of the 5’UTRs indicated significant sequence and length variation in this region, between the three South African variant groups. Nucleotide sequence alignment of the Hsp70h and CP gene regions of these isolates with those of isolates from elsewhere in the world, followed by phylogenetic analysis, further supported the presence of three GLRaV-3 variants in South Africa, and that two or three additional variant groups occurs elsewhere in the world. We further investigated the prevalence of these three GLRaV-3 variants in mother blocksof different cultivars and from different vine growing regions, using SSCP analysis. The majority of the plants studied, were infected with the group II variant, similar to isolates 623 and GP18. The distribution of the three GLRaV-3 variants within a spatio-temporally recorded cluster of diseased plants was studied by means of SSCP profile analysis. We showed that different GLRaV-3 variants are transmitted to adjacent plants in an infection cluster. Results showed that, in some leafroll disease clusters, the variant that was present in the original GLRaV-3 infected plant of a cluster was transmitted to adjacent plants in a row and across rows. Some plants in the cluster were also infected with variants not present in the original plant. These infections could have been caused by mealybug vectors feeding on plants from surrounding areas and then infecting these plants. The scientific information generated on GLRaV-3 variants in this project contributed to the advancement of our knowledge of genetic variability and provides a basis of further epidemiology and vector-virus studies. The study showed for the first time that different GLRaV-3 variants were transmitted to adjacent plants in a row and across rows in a GLR disease cluster. The diversity detected in the 5’UTR between variants from the three genetic groups provides a platform for the further study of the biological characteristics of GLRaV-3 variants. / AFRIKAANSE OPSOMMING: Wingerdsiektes, veral virus siektes, bedreig wingerd industrieë wêreldwyd, asook die Suid Afrikaanse wingerdbedryf. Rolbladsiekte is een van die belangrikste siektes op wingerd en kom wêreldwyd voor. Die virus, grapevine leafroll-associated virus 3 (GLRaV-3), word sterk geassosieer met Rolbladsiekte en kom wydverspreid voor in Suid Afrikaanse wingerde. Tydens hierdie studie is drie genetiese variante van GLRaV-3 geïdentifiseer in wingerd moederblokke in die Wes-Kaap. Die GLRaV-3 variante is geïdentifiseer met ‘n tegniek wat ‘single-strand conformation polymorphism (SSCP)’ genoem word. Die SSCP profiele was gegenereer vanaf PKR produkte van die ORF5 area op die genoom van GLRaV-3. Die geamplifiseerde produk van die ORF5 gebied is gebruik om die SSCP profiele te verkry en DNA-volgorde data in die gebied het die drie SSCP profiele gestaaf. Hierdie metode om virus variasie te bestudeer in plante is vinnig en betroubare resultate is verkry. Gemengde infeksies, wat gereeld in wingerd voorkom, kon ook met die tegniek opgespoor word. Die volledige nukleotied-volgorde van elkeen van die drie GLRaV-3 genome is volledig bepaal. Die isolate wat die drie variant groepe verteenwoordig is isolaat 621 (groep I), 623 (groep II) en PL-20 (groep III). Die nukleotiedvolgorde in die 5’UTR is bepaal met die RLM-RACE tegniek. Wanneer die 5’UTRs van die drie variante vergelyk is, het dit getoon dat daar verskille is in die volgordes en lengtes voorgekom het. Ander dele van die genoom, o.a. die dopproteïen (CP) en Hsp70 areas, is filogeneties vergelyk met isolate van regoor die wêreld. In die filogenetiese analise is bevind dat die drie GLRaV-3 variante saamgegroepeer het met ander isolate in die wêreld en dat daar elders ook twee to drie addisionele variant groepe van GLRaV-3 voorkom. Die verspreiding van die drie GLRaV-3 variante in wingerde is bestudeer in verskillende kultivars en in verskillende verbouingsgebiede. Die meerderheid van die plante in die studie was geïnfekteer met die groep II variant wat dieselfde is as isolate 623 en GP18. Die voorkoms van die drie variante in ‘n siekte cluster is bestudeer d.m.v SSCP. Die studie het gewys dat verskillende GLRaV-3 variante versprei word na aangrensende plante in ‘n ry en tussen rye. In sommige gevalle is die variant wat in die oorspronklik geïnfekteerde plant voorkom, oorgedra na naasliggende plante. Sommige van die plante in the infeksie area was ook met ander GLRaV-3 variante geïnfekteer wat moontlik deur wolluise oorgedra is vanaf naburige geïnfekteerde plante. Die wetenskaplike inligting wat tydens hierdie studie beskryf word aangaande die identifikasie van GLRaV-3 variante, dra by tot die molekulêre kennis van GLRaV-3 en verskaf ‘n basis vir verdure epidemiologiese -en insek oordragingstudies. Die studie het vir die eerste keer bewys dat verskillende GLRaV-3 variante na aanliggende plante in ‘n ry asook oor rye oorgedra word. Die diversiteit tussen die GLRaV-3 variant groepe in die 5’UTR moet verder ondersoek word en die deel van die genoom kan ‘n belangrike rol speel in die biologiese eienskappe van die variante.
6

Avaliação dos níveis de ingestão diária de edulcorantes pelo consumo de adoçantes líquidos de mesa / Evaluation of the intake of sweeteners by consuming tabletop weeteners

Del Bianchi, Michelle, 1982- 03 September 2012 (has links)
Orientador: Felix Guillermo Reyes Reyes / Dissertação (mestrado) - Universidade Estadual de Campiknas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T16:49:25Z (GMT). No. of bitstreams: 1 DelBianchi_Michelle_M.pdf: 2100554 bytes, checksum: 574b7310661133a3b473c024dee257a0 (MD5) Previous issue date: 2012 / Resumo: Edulcorantes sao compostos quimicos de origem sintetica ou natural que tem a propriedade de adocar alimentos, em substituicao total ou parcial a sacarose ou outros acucares e reduzem o teor calorico do produto resultante. A ingestao de adocantes artificiais no mundo tem crescido nos ultimos anos, com o objetivo principal de reduzir a ingestao calorica. O aumento global de doencas cronicas relacionadas com a ingestao de acucar, particularmente a obesidade e a diabetes, e tambem uma razao para o aumento do consumo de adocantes artificiais. O objetivo deste estudo foi avaliar a ingestao de adocantes artificiais atraves do consumo de adocantes de mesa liquidos e avaliar a possibilidade de consumo superior a sua ingestao diaria aceitavel (IDA) estabelecida por FAO/WHO comite de peritos em aditivos alimentares (JECFA). Inicialmente, uma pesquisa de campo foi realizada para avaliar qual marca de adocante de mesa liquido mais consumido no Brasil e as caracteristicas de uso do mesmo. Para tanto, um questionario foi enviado por correio eletronico, para individuos, com questoes relativas ao consumo de adocantes e, caso consumidos, aspectos de uso incluindo marca do adocante, ingestao e motivo de consumo. O questionario tambem continha perguntas sobre questoes socioeconomicas, demograficas e de saude. Em base a esta pesquisa, verificou-se quais sao as marcas de adocantes liquidos de mesa mais consumidas. Os edulcorantes presentes nesses adocantes mais consumidos sao: sacarina, ciclamato, aspartame e acessulfame-K. Foi realizada a quantificacao desses edulcorantes nos adocantes de maior consumo. Para a quantificacao de sacarina, aspartame e acessulfame-K foi utilizada a cromatografia liquida de alta eficiencia acoplada ao detector de arranjo de diodos (CLAE-DAD). A quantificacao de ciclamato foi realizada por espectrofotometria UV/Vis, em 314 nm, apos derivatizacao para N, Ndiclorociclohexilamina. Os metodos analiticos foram validados de acordo com os seguintes parametros de validacao: linearidade, faixa linear, especificidade, precisao (repetibilidade intra e inter dias), limite de deteccao (LOD) e limite de quantificacao (LOQ). Todos os metodos mostraram parametros de validacao de acordo com o guia para validacao de metodos analiticos estabelecidos pela Agencia Nacional de Vigilancia Sanitaria (ANVISA). A maioria das respostas ao questionario foram do genero feminio (70,2%) e provenientes da regiao Sudeste do Brasil (70,8%). Entre os entrevistados, 47% usavam adocantes liquidos de mesa. A maioria que relatou o uso de adocantes artificiais tinham entre 21 e 32 anos ou acima de 45 anos de idade. Destes, 83% afirmaram nao ter qualquer tipo de patologia e que a principal razao para o consumo de adocantes liquidos de mesa foi a preferencia em relacao ao acucar. Cerca da metade (54%) dos consumidores relataram sentir sabor desagradavel ou amargo quando consomem adocante e 32% nao sabiam qual era o edulcorante artificial contido no adocante. Os resultados da analise dos adocantes liquidos de mesa provenientes do mercado varejista indicou variacao significativa (p<0,05) na concentracao de edulcorante entre marcas e lotes da mesma marca. Com base nos resultados do questionario verificou-se qual e a marca mais consumida. Essa marca contem sacarina e ciclamato. Uma amostra dessa marca foi entregue a individuos adultos consumidores deste produto, para calcular o nivel de consumo dos edulcorantes artificiais. Foi verificado que a ingestao de sacarina e ciclamato atraves do consumo de adocantes liquidos de mesa representa, em media, 38,7% e 19,8% do valor de IDA do edulcorante, respectivamente. Considerando a variacao na concentracao de adocantes entre as marcas e lotes da mesma marca e que cada edulcorante artificial tem um valor de IDA estabelecido, recomenda-se que as concentracoes dos edulcorante em adocantes liquidos de mesa sejam apresentados na etiqueta da embalagem, para fornecer ao consumidor informacoes sobre seu consumo, e permitir controlar a sua exposicao total a estas substancias. Em geral, os resultados sugerem uma substituicao cada vez maior de acucar pelos adocantes artificiais, que indicam a necessidade de se obter dados sobre a ingestao total de adocantes artificiais, a fim de avaliar o risco de que estas substancias apresentam para a saude dos consumidores / Abstract: Artificial sweeteners are chemical compounds of synthetic or natural origin that have sweetening properties, as full or partial replacement of sucrose or other sugars, and reduce the caloric content of the resulting product. The intake of artificial sweeteners in the world has grown in recent years, with the primary goal of reducing caloric intake. The overall increase of chronic diseases relating to sugar intake, particularly obesity and diabetes, is also a reason for the increased consumption of artificial sweeteners. The aim of this study was to evaluate the intake of artificial sweeteners through the consumption of liquid tabletop sweeteners and evaluate the possibility of consumption exceeding their Acceptable Daily Intake (ADI) established by the FAO/WHO Joint Expert Committee on Food Additives (JECFA). Initially, a field survey was undertaken to assess which liquid tabletop sweetener brand had the largest market share of the retail market in Brazil and the characteristics of usage. For this purpose, a questionnaire was submitted by electronic mail to individuals with questions relating to their consumption of artificial sweeteners, and if consumed, aspects of usage including brand, frequency and motivation of consumption. In addition, the questionnaire contained questions regarding socio-economic, demographic and health status. Based on the results of the survey the specific artificial sweeteners present in the most widely used liquid tabletop sweetener brands were identified and quantified. The artificial sweeteners present in the most widely consumed brands are: saccharin, cyclamate, aspartame and acesulfame-K. Quantification of saccharin, aspartame and acesulfame-K in the commercial products was determined by high performance liquid chromatography coupled to a diode array detector (HPLC-DAD). Quantification of cyclamate was carried out by spectrophotometry UV/Vis, at 314 nm, after derivatization to N, N diclorocyclohexilamine. The analytical methods employed were validated according to the following validation parameters: linearity, linear range, specificity, accuracy, precision (repeatability intra-and inter-day), limit of detection (LOD) and limit of quantification (LOQ). All the methods showed validation parameters in accordance to the Guide for the Validation of Analytical Methods established by the Brazilian Agency of Sanitary Surveillance (ANVISA). Most of the responses to the questionnaire came from females (70.2%), from the southeast region of Brazil (70.8%). Among the respondents, 47% used artificial tabletop sweeteners. The majority of the respondents who reported using artificial sweeteners were between 21 and 32 years old or above 45 years old. Among these 83% reported not having any type of pathology and that the primary reason for artificial sweetener consumption was the preference in relation to sugar. Approximately half (54%) of consumers reported an unpleasant or bitter aftertaste when consuming the sweetener and 32% did not know which artificial sweetener was in the sweetener they used. The results of the analysis of the liquid tabletop sweeteners samples from the retail market indicated there is a statistical variation (p<0.05) in the sweeteners concentration between brands and batches from the same brand. Based on the questionnaire results, it was verified the most consumed brand. The brand contains saccharin and cyclamate. A sample of this brand was provided to adult volunteers to estimate the level of consumption of those artificial sweeteners. It was found that the intake of saccharin and cyclamate through the consumption of the liquid tabletop sweetener represent, on average, 38.7% and 19.8% of their ADI values, respectively. Considering the variation found in the sweeteners concentration between brands and batches from the same brand and that each artificial sweetener has an ADI value established, it is recommended that the concentrations of the artificial sweeteners in the liquid tabletop sweeteners be shown on the packaging label, to allow the consumer to make informed decisions regarding their intake and to allow them to better control their total exposure to these substances. In general, the results suggest an increasing replacement of sugar by artificial sweeteners, which indicate the need to obtain up to date data on the total intake of artificial sweeteners in order to assess the risk that these substances present to the consumers health / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos
7

Dynamiques socio-spatiales et modes d'habiter des espaces urbains : comparaison de Besançon, Mulhouse et Strasbourg / Socio-spatial dynamics and ways of living of urban spaces : comparison of Besançon, Mulhouse and Strasbourg

Najib, Kawtar 19 September 2013 (has links)
La répartition spatiale des fonctions et des populations urbaines n’est pas due au hasard, elle peutmettre en évidence des inégalités qui interrogent nos sociétés démocratiques fondées avant tout sur leprincipe d’égalité. Celui-ci s’appuie sur les relations entre le « social » et le « spatial » qui consistentprincipalement à explorer les inégalités sociales dans les espaces urbains et ce qui est ressenti commeune injustice par les individus. Pour saisir ces dynamiques socio-spatiales, nous focalisons notrerecherche sur l’histoire urbaine de Besançon, Mulhouse et Strasbourg ainsi que sur les rapports entreles habitants et leur environnement résidentiel. À l’aide des grandes bases de données géo-localiséesde l’INSEE, nous étudions la distribution spatiale des ménages ainsi que son évolution sur une périodede près de vingt années (de 1990 à 2007). Par ailleurs, nous cherchons à observer les différents modesd’habiter des Bisontins, c’est-à-dire leurs stratégies résidentielles ainsi que leurs pratiques etreprésentations spatiales à l’aide d’enquêtes de terrain. Cette thèse s’appuie donc sur une doubleapproche : l’une macroscopique, historique et quantitative et l’autre microscopique et qualitative. Elleprésente finalement les structures socio-spatiales des zones d’étude et les trajectoires des quartiers(plus précisément des IRIS) afin de montrer les diverses tendances d’évolution (gentrification,paupérisation…) dans une optique comparative. Des facteurs d’évolution spécifiques apparaissentégalement en lien avec la localisation des villes d’étude ainsi qu’avec leurs fonctions urbaines etsociales, leur organisation interne et leur taille. Les enquêtes révèlent, pour leur part, plusieurs règlescomportementales qu’il s’agit de comparer compte tenu de la diversité sociale des quartiers. Cesinformations collectées à partir d’enquêtes sont plus subjectives, mais elles complètent les données desrecensements et leur donnent du sens. Au final, elles montrent que l’appartenance à un groupe sociospatialene détermine pas systématiquement les comportements résidentiels. / The spatial distribution of urban functions and populations is not random, this distribution canhighlight inequalities which call into question our democratic societies based on the principle ofequality. This principle is based on the relationship between the “social” and the “spatial” whichmainly consist in investigating social disparities in urban areas and what is perceived as an injustice byindividuals. To understand these socio-spatial dynamics, we focus our research on the urban history ofBesançon, Mulhouse and Strasbourg as well as the relations between the inhabitants and theirresidential environment. Using large geo-localized databases from INSEE, we study the spatialdistribution of households and its evolution over a period of nearly twenty years (1990-2007). Inaddition, we seek to observe the various ways of living of the residents of Besançon, that is to say theirresidential logics and their spatial practices and representations via field surveys. Thus, this thesis isbased on a double approach: the first one is macroscopic, historic and quantitative and the second oneis microscopic and qualitative. The study presents the socio-spatial structures of the studied cities andthe trajectories of districts (more exactly the IRIS: the smaller census area) in order to show thedifferent trends of evolution (gentrification, pauperisation...) in a comparative perspective. Specificfactors of evolution are also linked to the location of the studied cities as well as to their urban andsocial functions, their internal organisation and their size. The field surveys, for their part, revealseveral behavioural rules that we compare considering the social diversity of districts. Thisinformation collected from surveys is more subjective, but it completes the census data and gives themmeaning. Finally, we show that the membership of a socio-spatial group does not determinesystematically residential behaviours.

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