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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.
71

Test on 15m Span Composite Cellular Beam.

Lawson, M., Aggelopoulos, E.S., Lam, Dennis January 2014 (has links)
no / Cellular beams are the preferred form of long span construction in multi-storey buildings. For efficient design of composite cellular beams, asymmetric sections are often manufactured in which the bottom flange is larger than the top flange. A further innovation is in the use of 80mm deep deck profiles which allows beam spacing to be increased to 4.5m, and so the effective slab width acting compositely with the long span beams is also increased. The values for shear connector (stud) resistance given in Eurocode 4 (EN 1994-1-1), when used in combination with these modern decking profiles, have led to problems in achieving the minimum degree of shear connection for composite beams in comparison to the former BS 5950-3. For secondary beams, the number of shear connectors that can be accommodated in a span is limited by the spacing of the deck ribs (typically 300mm for deep trapezoidal profiles), and it is found that even for pairs of shear connectors per deck rib, it is impossible to satisfy the shear connection rules in Eurocode 4 for long span asymmetric beams. SCI, with support from the Research Fund for Coal and Steel, is on the way to resolving this problem in design to Eurocode 4, and has completed a test on a 15.3m composite cellular beam at the University of Bradford. This is believed to be the longest composite cellular beam test ever carried out. The test was part-sponsored by ASD Westok.
72

Analysis of vertical rectangular abutments of a skewed rigid frame bridge for bending and extension

Bottenhofer, Anton J. 19 May 2010 (has links)
There has been no attempt made in this paper to compare the results contained herein to any results secured from previous experimental work. The equations presented are complete in themselves. Development of the equations for the abutments has been independent of the angle of skew. Therefore, they may be used with any solution or this type tor a slab of like material and same length knee, skewed at any angle. As a special case, a right rigid-frame bridge could also be analyzed by this method. / Master of Science
73

Experimental and Analytical Study of Vibrations in Long Span Deck Floor Systems

Sanchez, Telmo Andres 01 July 2008 (has links)
Experimental and analytical research was conducted to address the vibration properties of Long Span Deck Floor Systems (LSDFS). The research comprised three stages. In the first part, experimental in-situ tests were conducted on thirteen bays of buildings under construction. The natural frequencies and acceleration responses were captured to observe the vibration behavior of the tested floors. In the second part, a laboratory footbridge was constructed to determine the fixity level attained at the supports when a LSDFS is supported by CMU walls. For this purpose, the footbridge was tested with three support conditions, and a number of experiments were carried out to determine the dynamic properties of the structure. Static tests using both point and distributed loadings were conducted to measure the deflections at the footbridge midspan. The static test results were compared to the theoretical deflections for a pinned-end beam and a fixed-end beam. Dynamic tests using experimental modal analysis techniques were conducted to determine the natural frequencies and mode shapes of the structure. The measured fundamental natural frequency of the footbridge was compared to the frequencies calculated for a simply supported beam and a beam with fixed ends, to determine the degree of fixity attained in the connection between the LSDFS and the supporting walls. In the last part of the research, three analytical procedures to predict modal characteristics of long span deck floor systems are studied. Floor frequencies are calculated using finite element analyses. Two design guides for floor vibration analysis were used to calculate natural frequencies and response accelerations. The predicted results obtained from the analytical methods are compared to the experimental results to determine their accuracy. Recommendations for the use of the analytical methods are provided. / Master of Science
74

Vergleichende Untersuchungen zum teratogenen Potential von Detergentien und Retinol für die Entstehung von Wirbelsäulendefekten während der Embryogenese und Larvalentwicklung von Brachydanio rerio (Ham.Buch.) und Xenopus laevis (Daudin) / Comparing investigations of the teratogenic potential of detergents and retinol for the origin of spinal defects during embryogenesis and larval development of Brachydanio rerio (Ham.Buch.) and Xenopus laevis (Daudin)

Schlomm, Markus 04 May 2006 (has links)
No description available.
75

An Investigation Of The Relationship Between Working Memory Capacity And Verbal And Mathematical Achievement

Leblebicioglu, Aysegul 01 September 2012 (has links) (PDF)
This study aims to find out the relationship between Working Memory Capacity and Verbal and Mathematical Achievement. The participants were 60 students at Hacettepe University School of Foreign Languages Department of Basic English. For measuring working memory capacity, one simple (Digit Span Task) and one complex (Reading Span Task) were used. Verbal achievement of the participants was measured both in their native language (Turkish) and their foreign language (English). For measuring their native language achievement, the participants&rsquo / Turkish scores in Y&uuml / ksek&ouml / gretime Ge&ccedil / is Sinavi 2010 (Transition to Higher Education Examination) / and for measuring their foreign language achievement, the participants&rsquo / scores in Hacettepe University School of Foreign Languages Department of Basic English Elementary Groups Achievement Exams I and II were used. For measuring their mathematical achievement, the participants&rsquo / Mathematic scores in Y&uuml / ksek&ouml / gretime Ge&ccedil / is Sinavi 2010 (Transition to Higher Education Examination) were used. The data was analyzed using a statistical package program (SPSS Version 18.0). The data analysis results revealed that there is a relationship between working memory capacity and verbal and mathematical achievements of the participants. It was tentatively concluded that, as the working memory capacity of the participants increase, so might their achievement in verbal and mathematical subjects. This result was discussed in terms of its implications, which may be that, if working memory capacity could be improved / the cognitive processes which the working memory is responsible for might also improve.
76

Early Childhood iPad Use and Effects on Visual Spatial Attention Span

Espiritu, Maya 01 January 2016 (has links)
Despite the rising prevalence of mobile media in young children’s lives, little research exists that examines the effects of mobile media use on early childhood cognitive development. This study will explore how mobile media use, specifically iPad use, in early childhood affects development of visual spatial attention span. Researchers will recruit 160 participants, ages 3 to 6, and categorize them into three groups: TV viewers only, interactive iPad users, and passive iPad users. Children will complete a computer task to measure the length of their visual spatial attention span. Parents will report on the average daily amount of media use, their child’s top three most viewed or used programs and apps, and the pervasiveness of media use, as well as complete a demographics survey. Research assistants will rate the level of exogenous stimuli children are exposed to in their top three programs and apps. Researchers predict that iPad use will be associated with shorter visual spatial attention spans in comparison to TV viewing, due to longer amounts of use, higher levels of exogenous stimuli, and higher levels of pervasiveness. In addition, researchers hypothesize that interactive iPad use will correlate with the shortest visual spatial attention spans due to highest levels of exogenous stimuli and longest amounts of use. The results will help parents and educators to more effectively monitor young children’s mobile media usage.
77

Teste de memória de trabalho em libras: proposta e considerações / Test of working memory in libras: proposal and considerations

Nogueira, Newton da Rocha 29 March 2018 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-10T18:10:29Z No. of bitstreams: 2 Dissertação - Newton da Rocha Nogueira - 2018.pdf: 1987725 bytes, checksum: d101edf0bcd440b9e10d9c5e6723c50d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-10T18:12:31Z (GMT) No. of bitstreams: 2 Dissertação - Newton da Rocha Nogueira - 2018.pdf: 1987725 bytes, checksum: d101edf0bcd440b9e10d9c5e6723c50d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-10T18:12:31Z (GMT). No. of bitstreams: 2 Dissertação - Newton da Rocha Nogueira - 2018.pdf: 1987725 bytes, checksum: d101edf0bcd440b9e10d9c5e6723c50d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-29 / The cognitive construct of working memory (hereafter MT) has been shown to be extremely relevant in the development and linguistic use, and there is evidence of an association between greater working memory capacity (henceforth CMT) and better performance in L2 (ORTIZPREUSS; SANZ, 2016). Most of these studies involve oral languages, but there is still a lack of research on the relationship between CMT and sign language performance. In addition, it is necessary to verify the functionality of the multicomponent MT model (BADDELEY, 2000) for sign language (CORINA; KNAPP, 2006; EMMOREY, et al., 2008), observing the role of each subsystem Phonological buffer, episodic buffer and visuospatial sketch). In view of this, the following research question arises: How could be a Work Memory test that adequately measures the storage and processing capacity of information in Libras (Brazilian Sign Language)? The present work aims to elaborate and evaluate a test in Libras, denominated of Libras span that aims to retain signals in order of appearance and at the same time to say if these signals involve or not during their realization. This test was applied to a group of users of Libras (deaf and hearing) and correlated with numerical-based MT tests, known as digit span whose task is to remember numbers in ascending order and operation span whose task is to solve calculations and remember the last digits of each operation. The purpose of this correlation was to evaluate the reliability and validity of the test with signals. Results showed that the Libras span task can become a good tool for assessing working memory capacity in Libras / O construto cognitivo de memória de trabalho (doravante MT) tem se mostrado de extrema relevância no desenvolvimento e uso linguístico, havendo evidências de associação entre maior capacidade de memória de trabalho (doravante CMT) e melhor desempenho na L2 (ORTIZPREUSS; SANZ, 2016). A maioria desses estudos envolvem línguas orais, mas ainda há carência de pesquisas sobre a relação entre CMT e o desempenho em língua de sinais. Além disso, é preciso verificar a funcionalidade da arquitetura do modelo de multicomponente MT (BADDELEY, 2000) para a língua de sinais (CORINA; KNAPP, 2006; EMMOREY, et. al., 2008), observando o papel de cada subsistema (alça fonológica, buffer episódico e esboço visuoespacial). Em vista disso, surge a seguinte questão de pesquisa: Como poderia ser um teste de Memória de Trabalho que meça adequadamente a capacidade de armazenamento e processamento de informações em Libras? O presente trabalho tem como objetivo elaborar um teste em Libras, denominado de Libras span, cuja tarefa é memorizar sinais em ordem de aparecimento e, ao mesmo tempo, dizer se esses sinais envolvem ou não contato durante sua realização. Este teste foi aplicado a um grupo de usuários de Libras (surdos e ouvintes) e correlacionado com testes de MT de base numérica, conhecidos como digit span, cuja tarefa requer lembrar números em ordem crescente e operation span, cuja tarefa requer resolver cálculos e lembrar os últimos algarismos de cada operação. O propósito dessa correlação foi avaliar a confiabilidade e a validade do teste com sinais. Os resultados mostraram que, embora sejam necessários mais alguns ajustes, a tarefa Libras span pode tornar-se um bom instrumento de avaliação da capacidade de memória de trabalho em Libras.
78

Taluppfattning i ofördelaktiga förhållanden : Hur påverkar kognitiv förmåga perceptionen av enstaviga ord i brus bestående av talande röster?

Widman Börjesson, Sara January 2014 (has links)
Inom disciplinen kognitiv hörselvetenskap tillämpas en integrerad ansats där taluppfattning beskrivs ur både ett auditivt bottom-up-perspektiv och ett kognitivt top-down-perspektiv. Studien undersökte hur taluppfattning varierar med, respektive utan top-down-stöd och vad de kognitiva förmågorna uppmärksamhet, minne och inhiberingsförmåga hade för inverkan. Taluppfattningsförmåga utvärderades med hjälp av ett Speech-In-Noise-test (SIN-test) som bestod av tre deltest där enstaviga ord presenterades i en ofördelaktig miljö bestående av röster som talande i mun på varandra. I deltest 1 presenterades ord i uppåtgående förhållande till rösterna utan kognitivt stöd, i deltest 2 presenterades ord i nedåtgående förhållande till rösterna med kognitivt stöd och i deltest 3 presenterades ord i uppåtgående förhållande till rösterna med kognitivt stöd. Detta resulterade i identifiering av tre tröskelnivåer för taluppfattning. Kognitiva förmågor utvärderades med hjälp av Reading span test, Size Comparison span task (SIC-span) och Paced Auditory Serial-Addition Test (PASAT). Envägs variansanalys av taluppfattningstesten visade på signifikanta skillnader mellan alla tre testen. I test 2 identifierades lägst tröskelvärde, därefter test 3 och slutligen test 1. Korrelationsanalys visade på icke signifikanta samband mellan de tre SIN-testen. Av de kognitiva förmågorna och SIN- testen visade endast PASAT A på ett signifikant samband med SIN-test 2. Analys av de kognitiva förmågorna och differenserna mellan SIN-testen gav inga signifikanta samband. Slutligen vid analys av de kognitiva förmågorna hade PASAT A och PASAT B ett starkt positivt samband medan PASAT B och Reading span test hade ett starkt negativt samband. Resultaten i studien talade för att top-down-stöd ger bättre taluppfattningsförmåga och att uppmärksamhetskapacitet är en förmåga som har en signifikant inverkan på taluppfattning i nedåtgående förhållande till ett brus av röster.
79

Visual Attention among Patients with Schizophrenia: A Study of Visual Span and Selectivity in Visual Search

Elahipanah, Ava 09 January 2014 (has links)
Attention is one of the most impaired cognitive functions in schizophrenia; however, the precise mechanisms underlying schizophrenia-related attention impairment are unclear. Progress in identifying these mechanisms has been hampered by using methods that are not designed to isolate specific cognitive processes. The purpose of the present dissertation was to investigate visual attention among patients with schizophrenia using the visual search paradigm — the dominant paradigm for studying attention in the cognitive sciences. Moreover, the current study used eye-tracking methodology to more finely examine the mechanisms underlying impaired visual search in this clinical population. This dissertation had three main objectives: (1) to investigate whether patients with schizophrenia have smaller and/or less dynamic visual spans, (2) to examine whether certain mechanisms guiding the visual selection of objects are impaired in schizophrenia, and (3) to determine the contribution of visual search performance to substitution test performance. Results indicated that patients’ visual spans are both smaller and less dynamic compared to healthy controls. On the other hand, selectivity for more informative distractors is intact in schizophrenia; however, impaired motion perception results in impaired target discrimination in the context of intact target selection. Results also indicated that visual search performance is a primary determinant of substitution test performance. Collectively, these data demonstrate, on one hand, an impairment among patients with schizophrenia in the distribution and flexible modulation of visual attention and, on the other hand, intact visual selective attention in the presence of strong bottom-up cues. The current data also demonstrate the important contribution of visual attention to a highly sensitive neuropsychological test and, by inference, to patients’ cognitive and real-world functioning.
80

Visual Attention among Patients with Schizophrenia: A Study of Visual Span and Selectivity in Visual Search

Elahipanah, Ava 09 January 2014 (has links)
Attention is one of the most impaired cognitive functions in schizophrenia; however, the precise mechanisms underlying schizophrenia-related attention impairment are unclear. Progress in identifying these mechanisms has been hampered by using methods that are not designed to isolate specific cognitive processes. The purpose of the present dissertation was to investigate visual attention among patients with schizophrenia using the visual search paradigm — the dominant paradigm for studying attention in the cognitive sciences. Moreover, the current study used eye-tracking methodology to more finely examine the mechanisms underlying impaired visual search in this clinical population. This dissertation had three main objectives: (1) to investigate whether patients with schizophrenia have smaller and/or less dynamic visual spans, (2) to examine whether certain mechanisms guiding the visual selection of objects are impaired in schizophrenia, and (3) to determine the contribution of visual search performance to substitution test performance. Results indicated that patients’ visual spans are both smaller and less dynamic compared to healthy controls. On the other hand, selectivity for more informative distractors is intact in schizophrenia; however, impaired motion perception results in impaired target discrimination in the context of intact target selection. Results also indicated that visual search performance is a primary determinant of substitution test performance. Collectively, these data demonstrate, on one hand, an impairment among patients with schizophrenia in the distribution and flexible modulation of visual attention and, on the other hand, intact visual selective attention in the presence of strong bottom-up cues. The current data also demonstrate the important contribution of visual attention to a highly sensitive neuropsychological test and, by inference, to patients’ cognitive and real-world functioning.

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