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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.
61

Geoteknisk bärförmåga hos borrade injekterade pålar i åsmaterial Fältförsök: Slussen i Stockholm

Fischer, Torsten January 2012 (has links)
Fältförsöket projekterades av ELU-konsult i Stockholm på beställning av Stockholms stad.
62

Relationship between Subjective and Objective Measures of Attention in a Clinical Population of Children and Adolescents

Silk, Eric Edward 01 January 2012 (has links)
Attention problems can pose a serious challenge to the academic progress of children and adolescents. Currently, there are several different assessment methods utilized in the clinical diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD). Subjective and objective assessment measures purport to be measuring similar constructs of inattention, hyperactivity, and impulsivity. The present study examines the degree of correlation between the constructs of attention problems, hyperactivity/impulsivity, and signal detection between the Conners' Continuous Performance Test II Version 5 (CPT II) and a parent-report measure of attention problems, hyperactivity/impulsivity, aggression, emotional problems, and learning problems in a general clinical population of children and adolescents. This study also measures the correlation between these measures and the Woodcock Johnson III Tests of Cognitive Abilities (WJ-III COG) Auditory Attention subtest. No significant correlations were found among the CPT II errors of omission score or commissions score and attention problems or hyperactivity/impulsivity. No significant correlations were found among attention problems or hyperactivity/impulsivity and CPT II Reaction Time (RT), variability, or attentiveness. No significant correlations were found among the CPT II errors of omission or commissions scores and emotional problems, aggression, or learning problems. No significant correlations were found among the CPT II errors of omission score, commissions score, or RT and the WJ-III COG Auditory Attention subtest. A significant negative correlation was found between the CPT II variability score and the WJ-III COG Auditory Attention subtest. A significant positive correlation was found between the CPT II attentiveness score and the WJ-III COG Auditory Attention subtest. No significant correlations were found among any of the parent measures of attention problems Auditory Attention subtest. In a canonical correlation analysis there were high loadings on attention problems and hyperactivity/impulsivity on the parent-measure set and on commission errors and RT on the CPT II set. A modest loading on the multiple imputation set was also found on aggression problems and the parent-measure set. These findings support the overall conclusion that the CPT II does not generally relate to the parent-report measures. These findings indicate that there is little meaningful relationship between these two measures, which clinically are both used to assess attention problems.
63

Slope Stability Analysis Of Class I Landfills With Co Disposal Of Bios

Vajirkar, Mrutyunjay 01 January 2004 (has links)
Land filling provides a major, safe, and economical disposal route for biosolids and sludges. With an expanding world, the demand for larger and higher capacity landfills is rapidly increasing. Proper analysis and design on such fills have pushed the boundaries of geotechnical engineering practice, in terms of proper identification and assessment of strength and deformation characteristics of waste materials. The engineering properties of Municipal Solid Waste (MSW) with co-disposal of biosolids and sludges with regards to moisture characteristics and geotechnical stability are of utmost importance. Significant changes in the composition and characteristics of landfill may take place with the addition of sludges and biosolids. In particular, the stability of waste slopes needs to be investigated, which involves the evaluation of the strength properties of the mixture of the waste and biosolids. This thesis deals with impact of the addition of biosolids on the geotechnical properties of class I landfill as determined from field investigations. The geotechnical properties are evaluated using an in-situ deep exploration test, called the Cone Penetration Test (CPT). CPT provides a continuous log of subsurface material properties using two measuring mechanisms, namely, tip resistance and side friction. The areas receiving biosolids are compared with areas without, to evaluate the effect of landfilling of biosolids. The required geotechnical shear strength parameters (angle of internal friction and cohesion) of MSW and biosolids mixture are determined by correlation with CPT results similar to the procedure followed in evaluating soil properties. The shear strength parameters obtained from the CPT data are then used to study the stability of different slope configurations of the landfill. The slope stability analysis is conducted on the various landfill models using the computer software SLOPE/W. This software was designed for soils but was found to be suitable for modeling landfills, as the waste is assumed to act similar to a cohesionless soil. Based on the field investigations, the angle of internal friction was found to be about 29° and the determination of any cohesion was not possible. It was concluded that the most suitable practical solution to adding biosolids into the landfill was in the form of trenches. From the slope stability study, it was found that the factor of safety reduces significantly with the introduction of biosolids due to a reduction in shear strength and increase in the overall moisture content. From a parametric study, the stability of a 1:2 side slope with an angle of friction lower than about 20° was found to be less than the safe limit of 1.5. In addition, the factors of safety for landfills with trenches extending close to the edges of the slopes were also found to be unsafe and this situation needs to be avoided in practice.
64

Development of a Simplified Performance-Based Procedure for Assessment of Liquefaction Triggering for the Cone Penetration Test

Blonquist, Jenny Lee 06 April 2020 (has links)
Soil liquefaction can cause devastating damage and loss and is a serious concern in civil engineering practice. One method for evaluating liquefaction triggering potential is a risk-targeted probabilistic approach that has been shown to provide more consistent and accurate estimates of liquefaction risk than traditional methods. This approach is a “performance-based” procedure which is based off of the performance-based earthquake engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research (PEER) Center. Unfortunately, due to its complexity, performance-based liquefaction assessment is not often used in engineering practice. However, previous researchers have developed a simplified performance-based procedure which incorporates the accuracy and benefits of a full performance-based procedure while maintaining a more simplistic and user-friendly approach. Until now, these simplified performance-based procedures have only been available for the SPT (Standard Penetration Test). With the increasing popularity of the CPT (Cone Penetration Test), a simplified procedure is needed for CPT-based liquefaction assessment. This thesis presents the derivation of a simplified performance-based procedure for evaluating liquefaction triggering using the Ku et al. (2012) and Boulanger and Idriss (2014) models. The validation study compares the results of the simplified and full performance-based procedures. The comparison study compares the accuracy of the simplified performance-based and traditional pseudo-probabilistic procedures. These studies show that the simplified performance-based procedure provides a better and more consistent approximation of the full performance-based procedure than traditional methods. This thesis also details the development of the liquefaction loading maps which are an integral part of the simplified method.
65

Development of a Simplified Performance-Based Procedure for Assessment of Post-Liquefaction Settlement Using the Cone Penetration Test

He, Jingwen 01 July 2019 (has links)
Earthquake-induced liquefaction can cause severe damage to infrastructure is a serious concern in civil engineering practice. Post-liquefaction settlement is one of the common effects of liquefaction. The ability to predict and quantify post-liquefaction free-field settlement is a crucial part of seismic design. Many approaches have been developed during the past 50 years to perform liquefaction hazard analysis. The performance-based earthquake engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research (PEER) center is a probabilistic framework that can provide a more accurate and complete seismic hazard analysis than other traditional methods. However, the PBEE framework is not widely used in routine projects due to its complexity.Previous researches have been performed to develop simplified performance-based procedures that can combine the simplicity of a traditional method and the accuracy of the full performance-based method. Unfortunately, these simplified performance-based procedures are only available for SPT. With the increase use of CPT, there is a need to develop simplified performance-based procedures for CPT. This study develops simplified performance-based procedures for the assessment of post-liquefaction free-field settlement for CPT, using the Boulanger and Idriss (2014) and the Ku et al. (2012) triggering models. The Juang et al. (2013) model, which is a probabilistic version of the Ishihara and Yoshimine (1992) model, is used in this study to performance free-field settlement calculations. The simplified procedure is based on the idea of liquefaction reference parameter maps. Reference values obtained from these parameter maps are then adjusted, using correction equations, to site-specific conditions. This study presents the deviations of the correction equations for the simplified performance-based procedure. The simplified procedure will then be validated in which 18 cities across the United States are analyzed using both the simplified procedure and the full performance-based procedure. The simplified performance-based procedure is shown to reasonably estimate the results of the full performance-based procedure. Finally, a study is performed to compare the accuracy and consistency of the simplified performance-based and the conventional pseudo-probabilistic procedures. The simplified performance-based procedure is found to provide better approximations of the full performance-based procedure with more consistency and precision.
66

Contribuição ao estudo dos métodos de ensaio na avaliação das reações álcali-agregado em concretos. / Contribution to the study of test methods in assessing alkali-aggregate reactions in concrete.

Sanchez, Leandro Francisco Moretti 05 May 2008 (has links)
Muitas estruturas e elementos estruturais de concreto vêm sofrendo nas últimas décadas reações químicas deletérias do tipo álcali-agregado (RAA) no Brasil e no mundo. Essas reações geram expansões que podem comprometer a capacidade portante da estrutura, assim como o seu desempenho em serviço e sua durabilidade. Diagnosticar uma estrutura deteriorada pela RAA in loco é um assunto ainda pouco estudado, mas perfeitamente possível. Propor uma solução em termos de recuperação e/ou reforço é difícil e geralmente tem custo muito elevado, correndo-se o risco de que a solução, na maioria das vezes, seja ineficiente ou parcial. Até os dias atuais, não existe um consenso no meio técnico-científico no que tange a recuperação de estruturas afetadas por tal manifestação deletéria, devendo ser cada caso analisado de maneira única. No entanto, é consenso no meio técnico-científico que o ideal para combater a RAA é a prevenção. Para isto, torna-se necessário o desenvolvimento e a utilização de métodos experimentais, que possam de maneira antecipada detectar o risco da eventual futura reação deletéria. Este trabalho estuda os principais e mais utilizados métodos de ensaio para a análise de agregados e de combinações cimento/agregados em laboratório, fazendo ao seu final, uma análise crítica no que tange a eficiência e confiabilidade de cada um deles. Para o presente estudo, são utilizados seis agregados encontrados no Brasil, com quatro litologias diferentes (dois granitos, dois basaltos, um milonito e um quartzito). Entre os ensaios estudados, podem ser citados os métodos AMBT, (método acelerado de barras de argamassa), CPT (método dos prismas de concreto), ACPT (método acelerado de prismas de concreto) e ACPST (método acelerado de prismas de concreto imerso em solução), além de análises petrográficas através do microscópio ótico. Além da análise comparativa entre métodos de ensaio existentes, esta dissertação propõe ao meio técnico um novo método de ensaio, denominado ABCPT (método acelerado brasileiro de prismas de concreto). Este método foi desenvolvido com o intuito de possuir a confiabilidade de resposta do método CPT e a agilidade do ensaio ACPST. Os resultados demonstram que todos os métodos de ensaio realizados em concreto (CPT, ACPT, ACPST e ABCPT) possuem grande correlação entre si, podendo ser utilizado qualquer um deles para classificação da reatividade potencial de agregados em laboratório. Já o ensaio de barras de argamassa (AMBT) apresenta incongruências na análise e classificação de agregados quando comparado com os métodos realizados em concreto e a análise petrográfica. Portanto, os parâmetros que envolvem o ensaio como suas condições. / Many concrete structures have been suffering from alkali-aggregate reactions (AAR) since the last decades in Brazil and around the world. The reactions generate expansions that could compromise the strength of a concrete structure as well as its performance in service and its durability. Nowadays, it is completely possible to detect AAR in the field, but repair and reinforce a damaged structure is difficult, very expensive and in most cases inefficient or partial. There is no consensus in the market on how to repair and reinforce damaged structures. However, there is a consensus that the best way to face the problem is the prevention. This work studies the main test methods used to analyze aggregates and the combinations cement/aggregates in the laboratory and finally comparing them. In this work six Brazilian aggregates with four different lithologies (two granites, two basalts, one granite-gneiss and one quartzite) were used. Among the test methods studied were AMBT (accelerated mortar bar test), CPT (concrete prism test), ACPT (accelerated concrete prism test), ACPST (accelerated concrete prism soaked test) and petrographic analysis. Beyond the comparison among used tests, this work presents the attempt to develop a new accelerated test method. The test was called ABCPT (accelerated Brazilian concrete prism test), and it was developed with the aim of being as reliable as CPT and as fast as the ACPST. The results show that all concrete test methods (CPT, ACPT, ACPST and ABCPT) have good correlation among them, and anyone can be used to classify and analyze aggregates in the laboratory. On the other hand, the AMBT test method has showed different classifications for the same aggregates when compared to the concrete test methods and petrographic analysis. Therefore, its parameters need to be rethought and improved.
67

Desenvolvimento de uma sonda TDR helicoidal para uso em conjunto com o ensaio CPT / Developing a coil TDR probe to use together with the CPT test

Guerrero Doria, Katerin 21 August 2015 (has links)
A reflectometria no domínio do tempo permite estimar o teor de umidade de um meio através da sua correlação com a constante dielétrica. Uma sonda helicoidal TDR, que pode ser cravada em conjunto outros ensaios de penetração in situ para a estimativa do teor de umidade em diversas profundidades, tem aplicação interessante para a investigação geotécnica do subsolo. No presente trabalho, uma sonda TDR foi adaptada e utilizada em conjunto ao ensaio CPT para caracterização de um perfil de solo arenoso não saturado que ocorre na região de Bauru (SP). A calibração dessa sonda foi feita em laboratório especificamente para esse solo. As equações de calibração que mostraram os melhores resultados foram definidas correlacionando a constante dielétrica, condutividade elétrica aparente e a massa específica seca com o teor de umidade. Com o intuito de melhorar a acurácia na determinação do teor de umidade em campo e eliminar possíveis interferências no registro da onda eletromagnética, foram efetuadas modificações em algumas características do projeto original dessa sonda. Tais modificações consistiram em separar os eletrodos condutores e as partes metálicas da sonda, e eliminar o cabo coaxial de extensão, conectando a sonda diretamente a um cabo coaxial de 12 m de comprimento. Tais mudanças levaram a uma melhoria significativa na determinação do perfil de teor de umidade do local estudado. Os valores de teor de umidade de campo determinados usando o TDR ao longo de 8 m de profundidade foram comparados com os valores de referência obtidos de amostras deformadas retiradas com trado mecânico. O erro médio na estimativa do perfil de teor de umidade gravimétrico utilizando a sonda TDR helicoidal foi de 1.61%, na última campanha de ensaios realizados. Os resultados dessa pesquisa indicam que esta ferramenta é adequada para estimar do perfil de teor de umidade para uso em conjunto com o ensaio CPT. / The time domain reflectometry allows estimating the moisture content of a medium by means of its correlation with the dielectric constant. A coil TDR probe, which can be driven into the ground together with others in situ penetration tests, can be used to estimate the moisture content at different depths. It is an interesting approach for geotechnical site characterization. In this work, a coil TDR probe was adapted and used in combination with the CPT test for the site characterization of an unsaturated sandy soil profile which occurs in the region of Bauru (SP). The probe calibration was performed in laboratory specifically for that soil. The calibration equation, which presented the best results, were defined correlating the dielectric constant, electrical conductivity and dry density with the moisture content. In order to improve the accuracy for determining the water content in the field and to eliminate possible interference on the electromagnetic wave registration, modifications were made in some characteristics of the original design of this probe. Such modifications consisted in separating the conductive electrodes from the metal parts of the probe, and eliminating the coaxial extension cable, connecting the probe directly to a coaxial cable 12 m long. Such changes have led to a significant improvement in the determination of the moisture content profile of the studied site. The moisture content values determined in situ by using the TDR along 8 m depth were compared with reference values obtained from disturbed soil samples collected using mechanical augers. The root mean square error of the gravimetric water content profile using the TDR coil probe was 1.61% in the last test campaign. The results of this research indicate that this tool is suitable to estimate the gravimetric moisture content together with the CPT test.
68

Der Effekt des Alterns auf funktionelle Deaktivierung im somatosensorischen System / Eine fMRT-Studie / Effects of age on functional deactivation in the somatosensory system / fMRI study

Sohns, Jan Martin 09 December 2009 (has links)
No description available.
69

Desenvolvimento de uma sonda TDR helicoidal para uso em conjunto com o ensaio CPT / Developing a coil TDR probe to use together with the CPT test

Katerin Guerrero Doria 21 August 2015 (has links)
A reflectometria no domínio do tempo permite estimar o teor de umidade de um meio através da sua correlação com a constante dielétrica. Uma sonda helicoidal TDR, que pode ser cravada em conjunto outros ensaios de penetração in situ para a estimativa do teor de umidade em diversas profundidades, tem aplicação interessante para a investigação geotécnica do subsolo. No presente trabalho, uma sonda TDR foi adaptada e utilizada em conjunto ao ensaio CPT para caracterização de um perfil de solo arenoso não saturado que ocorre na região de Bauru (SP). A calibração dessa sonda foi feita em laboratório especificamente para esse solo. As equações de calibração que mostraram os melhores resultados foram definidas correlacionando a constante dielétrica, condutividade elétrica aparente e a massa específica seca com o teor de umidade. Com o intuito de melhorar a acurácia na determinação do teor de umidade em campo e eliminar possíveis interferências no registro da onda eletromagnética, foram efetuadas modificações em algumas características do projeto original dessa sonda. Tais modificações consistiram em separar os eletrodos condutores e as partes metálicas da sonda, e eliminar o cabo coaxial de extensão, conectando a sonda diretamente a um cabo coaxial de 12 m de comprimento. Tais mudanças levaram a uma melhoria significativa na determinação do perfil de teor de umidade do local estudado. Os valores de teor de umidade de campo determinados usando o TDR ao longo de 8 m de profundidade foram comparados com os valores de referência obtidos de amostras deformadas retiradas com trado mecânico. O erro médio na estimativa do perfil de teor de umidade gravimétrico utilizando a sonda TDR helicoidal foi de 1.61%, na última campanha de ensaios realizados. Os resultados dessa pesquisa indicam que esta ferramenta é adequada para estimar do perfil de teor de umidade para uso em conjunto com o ensaio CPT. / The time domain reflectometry allows estimating the moisture content of a medium by means of its correlation with the dielectric constant. A coil TDR probe, which can be driven into the ground together with others in situ penetration tests, can be used to estimate the moisture content at different depths. It is an interesting approach for geotechnical site characterization. In this work, a coil TDR probe was adapted and used in combination with the CPT test for the site characterization of an unsaturated sandy soil profile which occurs in the region of Bauru (SP). The probe calibration was performed in laboratory specifically for that soil. The calibration equation, which presented the best results, were defined correlating the dielectric constant, electrical conductivity and dry density with the moisture content. In order to improve the accuracy for determining the water content in the field and to eliminate possible interference on the electromagnetic wave registration, modifications were made in some characteristics of the original design of this probe. Such modifications consisted in separating the conductive electrodes from the metal parts of the probe, and eliminating the coaxial extension cable, connecting the probe directly to a coaxial cable 12 m long. Such changes have led to a significant improvement in the determination of the moisture content profile of the studied site. The moisture content values determined in situ by using the TDR along 8 m depth were compared with reference values obtained from disturbed soil samples collected using mechanical augers. The root mean square error of the gravimetric water content profile using the TDR coil probe was 1.61% in the last test campaign. The results of this research indicate that this tool is suitable to estimate the gravimetric moisture content together with the CPT test.
70

Contribuição ao estudo dos métodos de ensaio na avaliação das reações álcali-agregado em concretos. / Contribution to the study of test methods in assessing alkali-aggregate reactions in concrete.

Leandro Francisco Moretti Sanchez 05 May 2008 (has links)
Muitas estruturas e elementos estruturais de concreto vêm sofrendo nas últimas décadas reações químicas deletérias do tipo álcali-agregado (RAA) no Brasil e no mundo. Essas reações geram expansões que podem comprometer a capacidade portante da estrutura, assim como o seu desempenho em serviço e sua durabilidade. Diagnosticar uma estrutura deteriorada pela RAA in loco é um assunto ainda pouco estudado, mas perfeitamente possível. Propor uma solução em termos de recuperação e/ou reforço é difícil e geralmente tem custo muito elevado, correndo-se o risco de que a solução, na maioria das vezes, seja ineficiente ou parcial. Até os dias atuais, não existe um consenso no meio técnico-científico no que tange a recuperação de estruturas afetadas por tal manifestação deletéria, devendo ser cada caso analisado de maneira única. No entanto, é consenso no meio técnico-científico que o ideal para combater a RAA é a prevenção. Para isto, torna-se necessário o desenvolvimento e a utilização de métodos experimentais, que possam de maneira antecipada detectar o risco da eventual futura reação deletéria. Este trabalho estuda os principais e mais utilizados métodos de ensaio para a análise de agregados e de combinações cimento/agregados em laboratório, fazendo ao seu final, uma análise crítica no que tange a eficiência e confiabilidade de cada um deles. Para o presente estudo, são utilizados seis agregados encontrados no Brasil, com quatro litologias diferentes (dois granitos, dois basaltos, um milonito e um quartzito). Entre os ensaios estudados, podem ser citados os métodos AMBT, (método acelerado de barras de argamassa), CPT (método dos prismas de concreto), ACPT (método acelerado de prismas de concreto) e ACPST (método acelerado de prismas de concreto imerso em solução), além de análises petrográficas através do microscópio ótico. Além da análise comparativa entre métodos de ensaio existentes, esta dissertação propõe ao meio técnico um novo método de ensaio, denominado ABCPT (método acelerado brasileiro de prismas de concreto). Este método foi desenvolvido com o intuito de possuir a confiabilidade de resposta do método CPT e a agilidade do ensaio ACPST. Os resultados demonstram que todos os métodos de ensaio realizados em concreto (CPT, ACPT, ACPST e ABCPT) possuem grande correlação entre si, podendo ser utilizado qualquer um deles para classificação da reatividade potencial de agregados em laboratório. Já o ensaio de barras de argamassa (AMBT) apresenta incongruências na análise e classificação de agregados quando comparado com os métodos realizados em concreto e a análise petrográfica. Portanto, os parâmetros que envolvem o ensaio como suas condições. / Many concrete structures have been suffering from alkali-aggregate reactions (AAR) since the last decades in Brazil and around the world. The reactions generate expansions that could compromise the strength of a concrete structure as well as its performance in service and its durability. Nowadays, it is completely possible to detect AAR in the field, but repair and reinforce a damaged structure is difficult, very expensive and in most cases inefficient or partial. There is no consensus in the market on how to repair and reinforce damaged structures. However, there is a consensus that the best way to face the problem is the prevention. This work studies the main test methods used to analyze aggregates and the combinations cement/aggregates in the laboratory and finally comparing them. In this work six Brazilian aggregates with four different lithologies (two granites, two basalts, one granite-gneiss and one quartzite) were used. Among the test methods studied were AMBT (accelerated mortar bar test), CPT (concrete prism test), ACPT (accelerated concrete prism test), ACPST (accelerated concrete prism soaked test) and petrographic analysis. Beyond the comparison among used tests, this work presents the attempt to develop a new accelerated test method. The test was called ABCPT (accelerated Brazilian concrete prism test), and it was developed with the aim of being as reliable as CPT and as fast as the ACPST. The results show that all concrete test methods (CPT, ACPT, ACPST and ABCPT) have good correlation among them, and anyone can be used to classify and analyze aggregates in the laboratory. On the other hand, the AMBT test method has showed different classifications for the same aggregates when compared to the concrete test methods and petrographic analysis. Therefore, its parameters need to be rethought and improved.

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