• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 134
  • 33
  • 26
  • 15
  • 15
  • 10
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 313
  • 63
  • 42
  • 30
  • 27
  • 26
  • 26
  • 24
  • 23
  • 23
  • 21
  • 20
  • 20
  • 20
  • 20
  • 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.
101

Análise numérico-experimental de vigas de concreto armado com restrições axial e rotacional em situação de incêndio. / Experimental and numerical analysis of reinforced concrete beams with axial and rotational restraints in fire.

Gabriela Bandeira de Melo Lins de Albuquerque 09 May 2018 (has links)
As vigas de concreto armado sofrem deformações térmicas em situação de incêndio. Os comprimentos dos vãos se alongam resultando no deslocamento horizontal de seus respectivos apoios e elas passam a fletir de forma acentuada, o que gera a rotação nos mesmos. Se essas deformações forem impedidas pelas próprias condições de apoio da peça ou devido a elementos estruturais circundantes, por exemplo, esforços adicionais passarão a atuar nas vigas, modificando seu desempenho frente ao fogo. Estudos apontam que os efeitos desses esforços podem ser benéficos à resistência ao fogo (RF) das vigas aquecidas, contudo, nas poucas pesquisas voltadas à análise experimental dessa questão, as restrições foram admitidas apenas de forma isolada, i.e., ou as vigas estavam submetidas a restrições axiais ou a rotacionais. O efeito conjunto, mais representativo ao que ocorre na realidade, e a consideração de diferentes níveis de rigidezes impostos às deformações, foram avaliados em investigações numéricas sem dados experimentais apropriados para a validação dos resultados. Na presente Tese de Doutorado, avaliou-se experimentalmente o desempenho de vigas de concreto mediante a realização de ensaios de flexão em elementos em escala real e sob diferentes condições de apoio: sem restrições às deformações, com restrições apenas axiais e com restrições tanto axiais quanto rotacionais. Relativamente aos elementos restringidos, foram analisados dois níveis de rigidezes axial, 0,02 e 0,04EA/l, e rotacional, 1 e 2EI/l. Também houve ensaios de referência em vigas simplesmente apoiadas à temperatura ambiente para a verificação dos carregamentos e modos de ruptura. Os dados experimentais obtidos para diferentes esquemas estáticos de vigas motivaram a concepção de modelos numéricos que fossem representativos do comportamento dos mesmos. Com o auxílio do programa de computador DIANA, que tem base no método dos elementos finitos, foram criados modelos para as vigas ensaiadas à temperatura ambiente e ao fogo. Eles foram idealizados com a consideração de diversas propriedades características do comportamento não linear dos materiais e conduziram a boas correlações quando os seus resultados foram comparados aos obtidos em laboratório. A principal conclusão deste estudo numérico-experimental foi que a RF das vigas de concreto armado sempre aumentam quando admitido qualquer tipo de restrição (somente axial ou axial mais rotacional). Além disso, ao se fixar um valor para a restrição rotacional, as vigas com nível de restrição axial mais elevado apresentaram RF maiores do que aquelas com nível mais brando. O mesmo se verificou ao fixar a restrição axial e variar a rotacional. Vigas nos quais o efeito conjunto das restrições foi admitido conduziram a maiores RF do que aquelas apenas com restrição axial. Para a maior parte dos casos estudados, os aumentos das RF se mostraram significativos quando confrontados às vigas sem restrições. Assim, confirmou-se que os métodos simplificados normatizados que não consideram os efeitos provenientes das mesmas no dimensionamento para a situação de incêndio das vigas de concreto armado estão a favor da segurança. Os resultados numérico-experimentais aqui apresentados podem auxiliar na concepção de ferramentas alternativas para a consideração dos efeitos das restrições em projeto. / Reinforced concrete beams are submitted to thermal deformations when exposed to fire. The lengths of the spans elongate, a fact that triggers the horizontal displacement of their supports, and they begin to bend sharply, resulting in their rotation. If these deformations are hindered by the support conditions of the element or by surrounding structural elements, for instance, additional efforts will act on the beams in order to modify their performance when facing the action of fire. Studies have pointed out that the effects of such efforts may be beneficial to the fire resistance of the beams; however, in the few researches focused on the experimental analysis of this issue, the restraints were admitted only in an isolated way, i.e., the beams were either submitted to axial or to rotational restraints. Their coupled effect, more representative of what occurs in reality, and the consideration of different stiffness levels imposed on the deformations, were evaluated in numerical investigations, without suitable experimental data for validating the results, though. In this PhD Thesis, the performance of concrete beams was evaluated experimentally by performing bending tests on full-scale elements under different support conditions: unrestrained, only with axial restraints and with both axial and rotational restraints. Regarding the restrained elements, two levels of axial and rotational stiffness were analyzed, 0.02 and 0.04EA/l; 1 and 2EJ/l. There were also reference tests on simply supported beams at ambient temperature to check the load-bearing capacities and failure modes. The experimental data obtained for different beam static schemes still motivated the conception of numerical models that would be representative of their behavior. With the aid of the DIANA software, which is based on the finite element and displacement methods, beam models to represent beams tested at ambient temperature and in fire conditions were created. These models were implemented considering several properties that characterize the nonlinear behavior of the materials and led to good correlations when their results were compared to those obtained in the laboratory. The main conclusion of this experimental and numerical study was that the fire resistance of RC beams always increases when any type of restraint (axial or axial plus rotational) is introduced. In addition, by fixing the rotational stiffness, the beams with higher axial stiffness level presented higher fire resistance than those with the lower level. The same was observed by fixing the axial stiffness and varying the rotational stiffness. Beams in which the combined effect of the restraints was admitted led to higher resistances than those with only axial restraint. For most of the studied situations, the increases of the resistances showed to be significant when confronted with the ones for unrestrained beams. Thus, it was confirmed that the standard simplified methods that allow the non-consideration of these effects during the fire design of the RC beams lead to conservative results. The numerical and experimental results presented herein may aid in the conception of alternative tools that allow applying restraint effects to design.
102

A critical analysis of the concurrent enforceability of restraint of trade agreements and garden leave in South African Labour Law

Mahangwahaya, Musiiwa 18 May 2019 (has links)
LLM / Department of Mercantile Law / The study critically analyses the concurrent enforceability of restraint of trade and garden leave in South African Labour law. The study seeks to answer the question of whether or not the simultaneous enforceability of restraint of trade agreements and garden leave is reasonable. Designed within a qualitative paradigm primarily based on a critical literature review, the study employs a doctrinal approach to establish the contemporary legal position in respect of the simultaneous enforceability of restraint of trade agreements and garden leave in South African Labour law. The objectives pursued by the study are to mitigate the controversies and clear the confusion relating to the enforceability of restraint of trade agreements; to justify the doctrine of restraint of trade; assess the reasonableness of the simultaneous enforceability of garden leave and restraint of trade; examine the onus of proof in matters dealing with the enforceability of restraint of trade agreements; test the constitutionality of restraint of trade agreements; evaluate the relationship between restraint of trade agreements and garden leave; and propose practical recommendations that can be employed to address identified legal flaws in the context of the topic. Structurally, the study begins with unpacking the background to the research topic, the history, origin and rationality of restraint of trade agreements together with an assessment of their enforceability. It further examines the effect of garden leave on restraint of trade agreements, outlines comparative perspectives on restraint of trade, including aspects relating to garden leave and highlights lessons South Africa may learn from the selected jurisdictions. Finally, the study recommends that South African jurisprudence should be developed to shift the burden of proof to employers to prove reasonableness of garden leave and restraint of trade agreements, to impose an obligation on employers to pay former employees for rendering them jobless and to set a maximum period that an employee can be prevented to compete or be employed by employer’s competitors. / NRF
103

Reinforced Concrete Subjected To Restraint Forces : A comparison with non-linear numerical analyses / Armerad Betong Utsatt För Tvångskrafter : En jämförelse med icke-linjära numeriska analyser

Brattström, Niels, Hagman, Oliver January 2017 (has links)
In Sweden, it is Eurocode 2 which forms the basis for performing a design of concrete structures, in which methods can be found treating the subject of restrained concrete members and cracking in the serviceability limit state. In the code, both detailed hand calculations procedures as well as simplified methods are described. Several proposal of how to treat base restrained structures can be found in other codes and reports. Some state that the procedure given in Eurocode 2 is on the unsafe side as the method relies on stabilized cracking, while some say that the method is over conservative as the restraining actions will prevent the cracks from opening. As these methods are analysed closer and further tested, it is obtained that they all yield different results under the same assumptions. Most of them are within a similar span, and the deviation arises as the various methods takes different aspect into consideration. One method yields a result which is considerably higher than all other, denoted the Chalmers method. As this method is taught at the technical institute of Gothenburg (Chalmers), the large deviation have caused some confusion among Swedish engineers. As the methods are compared to numerical analyses, it is found that the detailed calculation procedure stated in Eurocode 2 yields fairly good prediction of crack widths for lower levels of strain, while for high levels of strain it is over conservative. The Chalmers method seems to underestimate the number of cracks which occur, and thus give rise to the deviating results. It is further found that in relation to more detailed hand calculations, the simplified procedure stated in Eurocode 2 may not always be on the safe side. The procedure is only valid within a certain range which may be exceeded depending on the magnitude of the load and choice of various design parameters. The effect creep have on base restrained structures subjected to long term loads such as shrinkage is further discussed and analysed numerically. Various hand calculation methods suggest that creep have a positive influence on base restrained structures in the sense that the crack width become smaller. The numerical results indicates that this is indeed the case, however, uncertainties of these analyses are considered to be large in relation to the short term analyses. / I Sverige är det Eurokod 2 som används som basis för dimensionering av betongkonstruktioner, i vilken metoder som beskriver sprickkontroll i bruksgränsstadiet för betong utsatt för tvångskrafter återfinns. Både detaljerade handberäkningsmetoder och förenklade metoder beskrivs. I olika koder och rapporter återfinns ett flertal förslag till hur detta problem ska hanteras. Vissa påstår att metoderna som anges i Eurokod 2 är på osäkra sidan då dessa förlitar sig på stabiliserad sprickbildning, medan andra menar att Eurokod 2 är för konservativ då inspänningen kommer förhindra att sprickorna öppnar sig. Då metoderna analyseras noggrannare och testas framgår det att alla genererar olika resultat under samma antaganden. De flesta ligger inom samma spann och skillnaderna uppkommer då de olika metoderna beaktar olika aspekter. En metod genererar dock ett resultat som är högre än alla andra, som i denna rapport benämns som Chalmersmetoden. Då denna metod lärs ut på Göteborgs tekniska universitet (Chalmers) så har de utstickande resultatet skapat en viss förvirring bland konstruktörer i Sverige. Då metoderna jämförs med numeriska analyser framgår det att Eurokod 2 förutspår en rimlig sprickvidd för låga töjningsgrader, medan den verkar vara överkonservativ för höga töjningsgrader. Chalmersmetoden verkar underestimera antalet sprickor som uppkommer i konstruktionen, vilket resulterar i de utstickande resultaten. Fortsättningsvis fastslås det att i relation till en mer detaljerad handberäkning så är den förenklade metoden i Eurokod 2 inte alltid på säkra sidan. Metoden är endast giltig inom ett visst spann, vilket kan överskridas beroende på den egentliga töjningens storlek och valet av dimensioneringsparametrar. Krypningens effekt på fastinspända betongkonstruktioner då de utsätts för långtidslaster så som krympning har också diskuterats och analyserats numeriskt. Olika handberäkningsmetoder antyder att krypningen har en positiv effekt på så sätt att sprickvidden minskar. Även de numeriska resultaten indikeratar att så är fallet, dock anses osäkerheten i dessa analyser vara stor i förhållande till analyser av korttidslaster.
104

Interaction between disinhibition and restraint: Implications for body weight and eating disturbance.

Bryant, Eleanor J., Keizebrink, K., King, N., Blundell, J.E. 03 1900 (has links)
yes / An increase in obesity is usually accompanied by an increase in eating disturbances. Susceptibility to these states may arise from different combinations of underlying traits: Three Factor Eating Questionnaire (TFEQ) Restraint and Disinhibition. Two studies were conducted to examine the interaction between these traits; one on-line study (n=351) and one laboratory-based study (n=120). Participants completed a battery of questionnaires and provided self-report measures of body weight and physical activity. A combination of high Disinhibition and high Restraint was associated with a problematic eating behaviour profile (EAT-26), and a higher rate of smoking and alcohol consumption. A combination of high Disinhibition and low Restraint was associated with a higher susceptibility to weight gain and a higher sedentary behaviour. These data show that different combinations of Disinhibition and Restraint are associated with distinct weight and behaviour outcomes.
105

The safety and effectiveness of interventions for aggression in mental health nursing

Parkes, J. January 2010 (has links)
This document presents five published journal articles all of which investigate the safety and effectiveness of interventions for aggression in mental health nursing. Early work focuses upon studies of the safety and effectiveness of interventions in the clinical setting. In the first article the research project examined the safety and effectiveness of a course of training in ‗control and restraint‘ (C&R) at a medium secure mental health unit. Mixed findings are reported, with some aspects of the study showing an increase in injuries whilst the overall outcome showed no significant change. The second article reports the pattern of incidents, and staff interventions, over a three year period in a different medium secure unit. A low threshold of reporting was encouraged and substantial numbers of incidents are described. Later work narrows the focus of the study onto a specific area of the safety of physical interventions for aggression: sudden death related to restraint. A published review of the literature on ‗positional asphyxia‘ is presented, discussing the key literature and developing the concept of ‗positional asphyxia.‘ Two research publications are also presented. In the first article the effect of body position on the rate of recovery from exercise is studied using pulse oximetry as a proxy measure of respiration. Equivocal results are reported. The second study shows a development of the methodology, following a similar design but using computer assisted pneumotachography to provide direct measurement of lung function. A clear pattern is demonstrated showing significant changes in lung function in prone restraint positions where the participant is flexed and/or body weight is applied. 4 The development of the concept of positional asphyxia and the contribution of the articles, academic and professional, is discussed. It is suggested that positional asphyxia should be viewed as one factor in a multi-factorial model of risk. The body of work is presented as having clear implications for practice. Early work examining the pattern of incidents in clinical settings has relevance to staff training, particularly in terms of a clearer understanding of the potential risks which need to be addressed by training. Later work has considerable implication for both policy and training by identifying those restraint positions which present less risk to the restrained person. Directions for future research are discussed.
106

Reducing Challenging Behaviors in Intellectually Disabled Individuals: A Comparison of Organizational Culture and Treatment Approach

Mascolo-Glosser, Frances 01 January 2015 (has links)
The deinstitutionalization of the intellectually disabled (ID) and their transition to community living in New York State necessitated training initiatives for staff to manage challenging behaviors safely and humanely. However, the use of physical interventions to control self-injury and physical aggression may have become organizationally habituated, and limited research has compared programs that use physical versus nonphysical interventions. This mixed-method, comparative case study compared a restraint-free day habilitation program with one that used physical interventions, examining the differences in reducing self-injury, aggression, and types of interventions applied. Qualitative differences in philosophical approach to behavior intervention strategies and staff training protocols were examined using semi-structured interviews with employees (n ¬=11). Insufficient sample size precluded inferential analyses, but descriptively the results revealed more incidents of physical assault and self-injury in the program that used physical interventions. Further, behaviors ceased without intervention more frequently than they did in the restraint-free program. Qualitative results revealed shared qualities of person-centered organizational culture across both programs. These results suggest that an organizational culture that incorporates training and staff support in the use of restraint-free strategies may influence the type and frequency of challenging behaviors in this population. This study promotes positive social change by providing information that the Office of Persons with Developmental Disabilities can use to inform the development of ID-serving agency policies and staff training protocols to promote safety, respect, and well-being in ID persons who access community learning services.
107

Genetic variants in AKR1B10 associate with human eating behavior

Rohde, Kerstin, Federbusch, Martin, Horstmann, Annette, Keller, Maria, Villringer, Arno, Stumvoll, Michael, Tönjes, Anke, Kovacs, Peter, Böttcher, Yvonne 25 March 2015 (has links) (PDF)
Background: The human Aldoketoreductase 1B10 gene (AKR1B10) encodes one of the enzymes belonging to the family of aldoketoreductases and may be involved in detoxification of nutrients during digestion. Further, AKR1B10 mRNA (messenger ribonucleic acid) expression was diminished in brain regions potentially involved in the regulation of eating behavior in rats which are more sensitive to cocaine and alcohol. We hypothesized that the human AKR1B10 gene may also play a role in the regulation of human eating behavior.
108

Predicting Weight Loss in Post Surgical Laparoscopic Banding Patients

Frensley, Susan J. 05 1900 (has links)
The present study was a retrospective chart review (N=128) that investigated the efficacy of profiles derived from the three factors of the Eating Inventory® test (EI) - cognitive restraint, disinhibition, and hunger - to predict successful weight loss in post surgical laparoscopic banding patients at 6 and 9 months post surgery. Although the EI is commonly used in bariatric presurgical assessment, few studies have found consistent relationships between presurgical factor scores and subsequent weight loss in this population. Based on restraint theory, 7 profiles (high CR, super high CR, high D, super high D, high H, super high H, and null) were derived from the raw scores on the subscales of the EI and tested for weight loss predictive ability using direct logistic regression. Results were mixed with high CR, super high CR, and null profiles accurately predicting successful weight loss. Raw scores on the three factors (cognitive restraint, disinhibition, and hunger) were tested individually for predictive ability using direct logistic regression. Overall results indicated that the profile model accurately predicted more cases than the general factor model. This study significantly contributes to both the bariatric presurgical assessment literature and the restraint theory literature. Suggestions for future research are offered.
109

Determinants of Effort and Associated Cardiovascular Response to a Behavioral Restraint Challenge

Agtarap, Stephanie 12 1900 (has links)
This study directly tested implications of motivation intensity theory on effort to restrain against a behavioral urge or impulse (i.e. restraint intensity). Two factors were manipulated—magnitude of an urge and the importance of successfully resisting it—with cardiovascular (CV) responses related to active coping measured. Male and female undergraduate students were presented with a mildly- or strongly evocative film clip with instructions to refrain from showing any facial response. Success was made more or less important through coordinated manipulations of outcome expectancy, ego-involvement, and performance assessment. As expected, systolic blood pressure responses assessed during the performance period were proportional to the evocativeness of the clip when importance was high, but low regardless of evocativeness when importance was low. These findings support a new conceptual analysis concerned with the determinants and CV correlates of restraint intensity. Implications of the study and associations with current self-regulatory literature are discussed.
110

Rebels against mines? : Explaining rebel restraint on landmine use

Siniciato Terra Garbino, Henrique January 2019 (has links)
Instead of state governments, rebel groups have become the most prolific landmine users. However, rebels display significant variation in the way they restrict the use of landmines. While some armed groups seek to limit their effects to government forces, some indiscriminately lay mines irrespective of collateral damage, and others directly target civilians with landmines. Furthermore, some rebels have renounced the use of anti-personnel mines and engage in mine action. In this thesis, I seek to explain this empirical variation. I argue that civilian victimisation caused by landmines creates significant legitimacy costs to rebels, thus increasing incentives to exercise restraint. It follows that the more legitimacy-seeking behaviour rebels display, the more likely they are to exercise restraint on landmine use. I test this hypothesis in a structured focused comparison of three rebel groups from the Philippines. The case studies support the hypothesis, as legitimacy-seeking behaviour had a positive effect on restraint on landmine use in the selected groups. This thesis contributes to the field mainly in two ways. First, I conceptualise and measure restraint on landmine use, which had been neglected in previous studies. Second, I develop a theoretical argument specifically explaining variation in restraint on landmine use.

Page generated in 0.0532 seconds