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Zhou, Xiao Yi. "Statistical analysis of traffic loads and traffic load effects on bridges." Phd thesis, UNIVERSITE PARIS-EST, 2013. http://tel.archives-ouvertes.fr/tel-00949929.
Повний текст джерелаАнотація:
Une grande majorité (85%) des ponts français a une portée inférieure à 50 m. Pour ce type d’ouvrage d’art, la charge de trafic peut être déterminante pour la conception et le recalcul. Or, en Europe, le fret routier a augmenté de 36.2% entre 1995 et 2010, et la croissance annuelle du volume transporté par la route a été évaluée à 1.7% entre 2005 et 2030. Il est donc essentiel de s’assurer que les infrastructures européennes sont en mesure de répondre à cette demande croissante en capacité structurelle des ouvrages. Pour les ouvrages neufs, les modèles de trafic dans les normes ou les législations pour la conception des ponts incluent une marge de sécurité suffisante pour que la croissance du trafic soit prise en compte sans dommage par ces ouvrages. Mais pour les ouvrages existants, la résistance structurelle aux trafics actuels et futur est à vérifier et une priorisation des mesures doit être faite pour assurer leur intégrité structurelle et leur sécurité. De plus, afin de préserver leur infrastructure tout en ne menaçant pas leur compétitivité nationale, certains pays réfléchissent à l’introduction de poids lourds plus longs, plus lourds, ce qui permet de réduire le nombre de véhicules pour un volume ou un tonnage donné, ainsi que d’autres coûts (d’essence, de travail, ..), ce qui justifie encore plus les calculs effectués. Pour répondre à ce genre de problématique, différentes méthodes d’extrapolation ont déjà été utilisées pour modéliser les effets extrêmes du trafic, afin de déterminer les effets caractéristiques pour de grandes périodes de retour. Parmi celles-ci nous pouvons citer l’adaptation d’une gaussienne ou d’une loi de Gumbel sur la queue de distribution empirique, la formule de Rice appliquée à l’histogramme des dépassements de niveaux, la méthode des maxima par blocs ou celle des dépassements de seuils élevés. Les fondements et les utilisations faites de ces méthodes pour modéliser les effets extrêmes du trafic sur les ouvrages sont donnés dans un premier chapitre. De plus, une comparaison quantitative entre ces méthodes est réalisée. Deux études sont présentées, l’une basée sur un échantillon numérique et l’autre sur un échantillon réaliste d’effets du trafic. L’erreur induite par ces méthodes est évaluée à l’aide d’indicatifs statistiques simples, comme l’écart-type et les moindres carrés, évalués sur les valeurs caractéristiques et les probabilités de rupture. Nos conclusions sont, qu’en général, les méthodes sont moins précises lorsqu’il s’agit de déterminer des probabilités de rupture que lorsqu’elles cherchent des valeurs caractéristiques. Mais la raison peut en être les faibles probabilités recherchées (10-6 par an). De plus, bien qu’aucune méthode n’ait réalisée des extrapolations de manière correcte, les meilleures sont celles qui s’intéressent aux queues de probabilités, et en particulier des dépassements au-dessus d’un seuil élevé. Ainsi une étude de cette dernière méthode est réalisée : en effet, cette méthode, nommé "dépassements d’un seuil élevé", considère que les valeurs au-dessus d’un seuil correctement choisi, assez élevé, suit une distribution de Pareto généralisée (GPD). Cette méthode est utilisée de manière intensive dans les domaines de l’hydrologie et la finance, mais non encore appliquée dans le domaine des effets du trafic sur les ouvrages. Beaucoup de facteurs influencent le résultat lorsqu’on applique cette méthode, comme la quantité et la qualité des données à notre disposition, les critères utilisés pour déterminer les pics indépendants, l’estimation des paramètres et le choix du seuil. C’est pour cette raison qu’une étude et une comparaison des différentes méthodes d’estimation des paramètres de la distribution GPD sont effectuées : les conditions, hypothèses, avantages et inconvénients des différentes méthodes sont listés. Différentes méthodes sont ainsi étudiées, telles la méthode des moments (MM), la méthode des moments à poids (PWM), le maximum de vraisemblance (ML), le maximum de vraisemblance pénalisé (PML), le minimum de la densité de la divergence (MDPD), la méthode des fractiles empiriques (EPM), la statistique du maximum d’adaptation et la vraisemblance des moments (LM). Pour comparer ces méthodes, des échantillons numériques, des effets de trafic simulés par Monte Carlo et des effets mesurés sur un ouvrage réel sont utilisés. Comme prévu, les méthodes ont des performances différentes selon l’échantillon considéré. Néanmoins, pour des échantillons purement numériques, MM et PWM sont recommandées pour des distributions à paramètre de forme négatif et des échantillons de petite taille (moins de 200 valeurs). ML est conseillé pour des distributions à paramètre de forme positif. Pour des effets du trafic simulés, ML et PML donne des valeurs de retour plus correctes lorsque le nombre de valeurs au-dessus du seuil est supérieur à 100 ; dans le cas contraire, MM et PWM sont conseillés. De plus, comme c’est prouvé dans l’étude de valeurs réelles mesurées, les valeurs a priori aberrantes ("outliers") ont une influence notable sur le résultat et toutes les méthodes sont moins performantes. Comme cela a été montré dans la littérature, ces "outliers" proviennent souvent du mélange de deux distributions, qui peuvent être deux sous-populations. Dans le cas de l’effet du trafic sur les ouvrages, cela peut être la raison d’une estimation des paramètres non correcte. Les articles existant sur le sujet soulignent le fait que les effets du trafic sont dus à des chargements indépendants, qui correspondant au nombre de véhicules impliqués. Ils ne suivent pas la même distribution, ce qui contredit l’hypothèse classique en théorie des valeurs extrêmes que les événements doivent être indépendants et identiquement distribués. Des méthodes permettant de prendre en compte ce point et utilisant des distributions mélangées (exponentielles ou valeurs extrêmes généralisées) ont été proposées dans la littérature pour modéliser les effets du trafic. Nous proposons une méthode similaire, que nous appelons dépassement de seuils mélangés, afin de tenir des différentes distributions sous-jacentes dans l’échantillon tout en appliquant à chacune d’entre elles la méthode des dépassements de seuil. Pour des ponts ayant des portées supérieures à 50 m, le scénario déterminant est celui de la congestion, qui n’est pas ce qui est étudié ici. De plus, le trafic n’est pas la composante déterminante pour la conception des ponts de longue portée. Mais des problèmes de fatigue peuvent apparaître dans certains ponts, tels les ponts métalliques à dalle orthotrope, où l’étude du trafic peut devenir nécessaire. Ainsi nous avons fait une étude de l’influence de la position des véhicules sur le phénomène de fatigue. Pour cela, quatre fichiers de trafic réels, mesurés en 2010 et 2011 par quatre stations de pesage différentes, ont été utilisés. Ils ont mis à jour des comportements latéraux différents d’une station à l’autre. Si nous les appliquons au viaduc de Millau, qui est un pont métallique à haubans et à dalle orthotrope, nous voyons que l’histogramme des effets et l’effet de fatigue cumulé est beaucoup affecté par le comportement latéral des véhicules. Ainsi, des études approfondies utilisant les éléments finis pour modéliser les ouvrages et des enregistrements de trafic réel, peuvent être utilisées pour pré-déterminer quels éléments, donc quelles soudures, doivent être examinés dans les ponts afin d’estimer leur santé structurelle.
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Güngör, Güven. "Biaxial Load Effects on Fatigue Properties." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19079/.
Повний текст джерелаАнотація:
This study aims to aid many issues related to fatigue, namely biaxial loading, the definition of the finite geometry correction factor of the stress intensity factor and the understanding of the energy dissipation per fatigue crack growth. In our work, we are using the geometry correction factor definition that uses the ratio
of external work introduced to the material. Using different biaxiality ratios varies the external work done, thus makes it possible for us to observe how the geometry correction factor handles this variation. The trend of strain energy release rate per crack growth is also investigated through biaxiality. Moreover,
the common discussion of the effects of biaxiality on fatigue properties is aided with yet another study. For this purpose, cruciform shaped plate specimen from an aluminum alloy are manufactured and biaxially loaded. Crack growth is observed while load-to-displacement data is recorded to evaluate the external work done on the specimen. As a result, it is seen that biaxiality delays the fatigue failure. Crack growth rates decreases as the biaxiality increases for a given effective stress intensity factor. Making use of the work values for the calculation of the finite geometry correction factor handles the effects of
biaxiality well. Strain energy release rate increases as the crack propagates, but there is no trend between strain energy release rate and biaxiality of the loading. In the future works, observing also the crack tip plasticity and trying out a wider range of biaxiality ratios with different types of material would result in more generalizable conclusions. Moreover, more repetitions of the fatigue tests would give more accurate values for the amount work introduced to the material with changing biaxiality.
3
Islam, Shariful. "Load Rating Study of Effects of Special Hauling Vehicle Loads on Ohio Bridges." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544818358028013.
Повний текст джерела
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James, Gerard. "Analysis of traffic load effects an railway bridges." Doctoral thesis, KTH, Civil and Architectural Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3523.
Повний текст джерелаАнотація:
The work presented in this thesis studies the load and loadeffects of traffic loads on railway bridges. The increasedknowledge of the traffic loads, simulated using fieldmeasurements of actual trains, are employed in a reliabilityanalysis in an attempt at upgrading existing railwaybridges.
The study utilises data from a weigh-in-motion site whichrecords, for each train, the train speed, the loads from eachaxle and the axle spacings. This data of actual trainconfigurations and axle loads are portrayed as moving forcesand then used in computer simulations of trains crossing twodimensional simply supported bridges at constant speed. Onlysingle track short to medium span bridges are considered in thethesis. The studied load effect is the moment at mid-span. Fromthe computer simulations the moment history at mid-span isobtained.
The load effects are analysed by two methods, the first isthe classical extreme value theory where the load effect ismodelled by the family of distributions called the generalisedextreme value distribution (GEV). The other method adopts thepeaks-over-threshold method (POT) where the limiting family ofdistributions for the heights to peaks-over-threshold is theGeneralised Pareto Distribution (GPD). The two models aregenerally found to be a good representation of the data.
The load effects modelled by either the GEV or the GPD arethen incorporated into a reliability analysis in order to studythe possibility of raising allowable axle loads on existingSwedish railway bridges. The results of the reliabilityanalysis show that they are sensitive to the estimation of theshape parameter of the GEV or the GPD.
While the study is limited to the case of the ultimate limitstate where the effects of fatigue are not accounted for, thefindings show that for the studied cases an increase inallowable axle load to 25 tonnes would be acceptable even forbridges built to the standards of 1940 and designed to LoadModel A of that standard. Even an increase to both 27.5 and 30tonnes appears to be possible for certain cases. It is alsoobserved that the short span bridges ofapproximately fourmetres are the most susceptible to a proposed increase inpermissible axle load.
Keywords:bridge, rail, traffic load, load effect,dynamic amplification factor, extreme value theory,peaks-over-threshold, reliability theory, axle loads, fielddata.
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FERREIRA, MARCELO PIERI. "ESTIMATION OF THE SHORTAGE EFFECTS IN LOAD FORECASTING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4545@1.
Повний текст джерелаАнотація:
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOREsta dissertação investiga os efeitos do racionamento de energia elétrica ocorrido no período entre junho de 2001 a fevereiro de 2002, nas previsões de energia das principais concessionárias brasileiras. Para tal, estudamos o desempenho de modelos lineares e não-lineares. Dentre os modelos lineares, analisamos os modelos ARIMA (p,d,q) de Box & Jenkins e os modelos de amortecimento exponencial de Holt & Winters. Dentre os modelos não-lineares, são abordadas técnicas de inteligência artificial tais como Redes Neurais e Lógica Fuzzy. Visto que o racionamento levou a previsões ineficientes, propomos alternativas para reduzir seu impacto. Por último, investigamos os impactos causados pela crise energética nas previsões doze passos à frente de carga elétrica provenientes de vinte e oito concessionárias. A base de dados é composta pelos valores observados e as previsões fornecidas pelo PREVCAR, um dos sistemas de previsão da cadeia oficial de programas do setor elétrico brasileiro. Por meio de um procedimento de Análise de Agrupamento utilizando Redes Neurais Artificiais do tipo SOM (Self Organizing Map) de Kohonen são estabelecidos os grupos de concessionárias que possuem os mesmos comportamentos diante do racionamento. Como resultado final, foram estimados fatores de redução das previsões causados pelo racionamento, que servem como base de cálculo para reduções nas previsões futuras em períodos de crise de abastecimento.
This dissertation aims at an exploratory study of impacts caused by the 2001 energy crisis on the current forecasts produced on a monthly basis for main distributing utilities. For that we show an accuracy study of the performance of the linear and non-linear models. It has been used, within the linear models class, the modeling approach of Box-Jenkins and exponential smoothing of Holt- Winters. Within the non-linear ones, it was chosen those based on artificial intelligence techniques, such as Fuzzy Logic and Artificial Neural Network. Due to the lack of accuracy of the models to cope with the discontinuities provoked by the crisis on the forecasts, some alternative tools to reduce the impact on the forecast errors are proposed. Finally, the impacts caused by the crisis on multiple steps ahead forecasts have also been investigated. It was taken the monthly forecasts produced by PREVCAR (one of official Brazilian load forecasting system), as well as the observed values covering the same period, to create the crisis response indices series for each one of the twenty and eight utilities included in the analysis. It was also used the well-known neural network based algorithm SOM (Self Organizing Maps) to classify the utilities into homogeneous groups, according to their response to the energy crisis. As a final result, for each group, it was estimated the reduction factors that can be used as a prior information in future energy supply crisis.
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URAO, Akira, and Kazuhisa MIWA. "EFFECTS OF COGNITIVE LOAD IN COMPUTER-BASED LEARNING ENVIRONMENTS." INTELLIGENT MEDIA INTEGRATION NAGOYA UNIVERSITY / COE, 2006. http://hdl.handle.net/2237/10472.
Повний текст джерела
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Ross, Patricia. "Electrophysiology of working memory, task modality and load effects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51224.pdf.
Повний текст джерела
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Tabarra, M. "Load factor effects on thermally stratified solar storage tanks." Thesis, De Montfort University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356458.
Повний текст джерела
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ARAUJO, THIAGO GOMES DE. "ADJUSTING LOAD SERIES BY THE CALENDAR AND TEMPERATURE EFFECTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=23850@1.
Повний текст джерелаАнотація:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O objetivo do presente trabalho é a geração de uma série mensal de carga elétrica livre das variações de calendário e de temperatura. Para tal, foram comparadas duas abordagens, uma totalmente empírica e outra híbrida com métodos empíricos e modelagens de regressão dinâmica, para identificar a mais adequada para a retirada desses ofensores. Os dados utilizados são provenientes de observações diárias de cada um dos quatro subsistemas que integram o Sistema Interligado Nacional (SIN), porém a ideia é produzir séries mensais do SIN e não apenas de cada um dos subsistemas. A série trimestral do PIB foi utilizada para decidir qual abordagem melhor ajustou os dados de Carga. A série mensal de carga ajustada do SIN será utilizada para subsidiar decisões, de compra e venda de energia nos leilões, das empresas distribuidoras de energia elétrica.
This thesis proposes a method to generate monthly load series free of variations coming from two sources: calendar and temperature. Two approaches were considered, one totally empirical and another one called hybrid, as it use empirical procedure to remove the calendar effect and a dynamic regression type of model to remove the temperature effects. The data set used comes found to daily observations from each one of the four subsystems that form the SIN (Brazilian Integrated Grid). However the final task is to obtain a unique monthly series for the SIN and not only the four subsystems monthly series. The quarterly PIB series was used to check the performance of the two proposed methods. Such adjusted series are quite important tools to hold on the decision of acquisitions and dailes of energy in the energy audits.
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Kai, Lauren C. (Lauren Catherine). "Effects of varying inertial load on human wrist movement." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32938.
Повний текст джерелаАнотація:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 44).
To study natural wrist movements in human subjects, a magnetic motion sensing system was employed to document unimpeded motion. Three identical bottles of different weights were designed as handles to provide a wide range of inertial loads. Subjects executed a series of horizontal and vertical moves with each bottle at two different speeds. Hypotheses concerning the effects of increased load on target overshoot, maximum acceleration and speed, and hand tremors were tested. The frequency content seen in the natural speed trials was found to resemble a normal distribution. This higher area of frequency content could potentially correlate with the frequency of hand tremors. After analysis of overshoot, there was found to be no statistical difference in the percent overshoot of movements by varying the weight of the handles. The data showed that the highest accelerations and speeds of the empty bottle were faster than those of the medium weight or the heavy weight bottle. One possible interpretation of this is that human wrist movement is force limited and there is a maximum acceleration at which humans can move.
by Lauren C. Kai.
S.B.
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Guduru, Manish Reddy. "Investigating the effects of load on the XIFI node." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-10862.
Повний текст джерелаАнотація:
Having a good understanding of the load requirements in the datacenter improves the capability to effectively provision the resources available to the meet the demands and objectives of application services. Especially in a large project like XIFI this aspect becomes even more critical because of the limited availability of the resources and the complexity of the various entities present.In this study we frame a structure that provides deep insights to comprehend XIFI infrastructure. Further, we model the user requests that approach the node for resource allocation to run their applications. We aim to provide an understanding on different aspects involved in modelling. The objective of this present study is to investigate the effect of load on the XIFI node. To achieve this objective, we model the XIFI node by examining the various entities involved in it. Furthermore, we provide an overview about what constitutes as load in the XIFI node.We conduct a detailed specifications study after which we identify the imperative entities required for the modelling of both the XIFI node and the requests. We examine the model by simulating it in CloudSim for two different scenarios varying the specifications.We simulated the designed structure for 30 iterations and analyzed 10,000 user requests for two cases where total RAM of the node is increased in the second case when compared to the first case. We analyze the CPU usage, RAM usage, Bandwidth usage and Storage usage in both the cases and examine the effects of the user requests on each one of them.The results provided evidence that the load indices on the host are dependent on each other. Also, it showed that the request modelling had an impact on the load of the host. It can also be concluded that the resource provisioning can be effective if the user behavior is known.
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Angeles, Antolin Linan Maria. "Effects of load modelling on Voltage Impasse Regions (VIR)." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254416.
Повний текст джерелаАнотація:
Voltage Impasse Region (VIR) is a phenomenon in power systemswhose dynamics are describe by a set of Differential AlgebraicEquations (DAE). VIR denotes a state-space area where voltagecausality is lost, i.e. the Jacobian of the algebraic part of DAEis singular. In a Time Domain Simulation (TDS) once system trajectoriesenter VIR, TDS experiences non-convergence of the solution.Then, there is no reason to continue with the simulation. Thisis why it is important to understand the mechanisms that introduceVIR. It is known that VIR appears in relation to static, non-linearload models. However, it remained unknown what the cumulativeeffect of several static, non-linear loads would be.This master thesis has further expanded the concept of VIRby carrying out a structured study on how the load modelling affectsVIR. For this purpose, this thesis proposes a quasi-dynamicmethodology to map VIR in the relative rotor angle space. Themethodology introduces a new discrete index called Voltage ImpasseRegion Flag (VIRflag), which allows to determine if the algebraicequations of DAE are solvable or not and, thus, to locate VIR.A test system is used to test the proposed quasi-dynamic approach.The VIRflag was first used to map VIR for various load combinations.Then, the relationship between TDS non-convergence issuesand the intersection of a trajectory with VIR is examined toverify the proposed methodology.The proposed method has been proved to be efficient in the determinationof VIR regardless of the number of non-linear loads inthe power system. Among the static exponential load models, theConstant Power (CP) load component has been identified as theone with the largest influence on VIR appearance and shape. TheConstant Current (CC) loads induce ”smaller" VIR areas and theConstant Impedance (CI) load can only alter the shape of VIR inthe presence of non-linear load models.VIR (Voltage Impasse Regions) är ett fenomen i kraftsystem varsdynamiska förlöp beskrivs av differential-algebraiska ekvationer(DAE). VIR betecknar ett område i tillståndsrummet där går förlorad,dvs Jakobianen av den algebraiska delen av DAE är singulärI tidsdomän-simuleringar (TDS) när en trajektoria träffar VIR,konvergerar TDS inte till en lösning. Då finns ingen anledning attfortsätta med simuleringen. Därför är det viktigt att förstå mekanismernasom introducerar VIR. Det är känt att VIR är relateradetill statiska, icke-linjära lastmodeller. Det var dock okänt vadden kumulativa effekten av flera statiska, icke-linjära belastningarskulle vara.Denna uppsats har vidareutvecklat begreppet VIR genom attgenomföra en strukturerad studie om hur lastmodellering påverkarVIR. För detta ändamål föreslår denna avhandling en kvasidynamiskmetod för att kartlägga VIR i det relativa rotorvinkelrummet.Metoden introducerar ett nytt diskret index som heterVoltage Impasse Region Flag (VIRflag), vilket gör det möjligt attbestämma om den algebraiska delen av DAE är lösbar eller inteoch därmed lokalisera VIR. Ett används för att testa det föreslagnakvasi-dynamiska tillvägagångssättet. VIRflag användes först för attkartlägga VIR för olika belastningskombinationer. Därefter granskasförhållandet mellan konvergensproblem i TDS och korsningenmellan en trajektoria och VIR för att verifiera den föreslagna metoden.Den föreslagna metoden har visat sig vara effektiv vid bestämningav VIR, oberoende av antalet icke-linjära belastningar. Bland destatiska exponentiella belastningsmodellerna har konstanteffektlast(CP) haridentifierats som den som har störst inflytande påVIR;s form. Den konstantströmlasten (CC) inducerar mindre"VIRområdenoch konstantimpedanslasten (CI) kan endast ändra formenav VIR i närvaro av icke-linjära belastningsmodeller.
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Iribe, Gentaro. "Effects of mechanical load on calcium handling in cardiac myocytes." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487260.
Повний текст джерелаАнотація:
In the 'in sitrl heart, electrical excitation of cardiac myocytes induces Ca2+ influx into the cytosolic space, which initiates muscle contraction (excitation contraction coupling) against a background of dynamically changing pre- and afterload conditions. On the other hand, mechanical load affects Ca2+ handling, either directly, or indirectly via modulation of electrical activity (mechano-electric feedback). The aim of this Thesis is to investigate and quantitatively describe the interactions between mechanical activity and Ca2+ handling, using experimental and mathematical modelling tools. Although there are a number of mathematical cardiac cell models available, few are aimed at reproducing beat-by-beat behaviour of Ca2+ handling. Therefore, we developed an original cell model which allows one to reproduce beat-by-beat changes in Ca2+ handling and resultant force production, which formed the basis for mathematical integration of the experimental findings of our Ca2+ handling study in this thesis. For e};perimental research, we developed a novel single cell force-length clamp (MyoStretcher), which uses piezo-control of carbon fibres (CF) to dynamically restrain the mechanical environment of isolated intact cardiomyocytes.Using the M):oStretcher, we subjected single isolated myocardial cells to dynamic contractions with work-loop style force-length (FL) relation, similar to those experienced by the cell 'in sittl. Single cell mechanics studies revealed that the end-systolic FL relation (ESFLR) IS load-independent In ventricular cardiomyoeytes of small mammals (Guinea pig). Modelling-based simulation studies suggest that the load-independent behaviour of ESFLR is the result of the combined effects ofload-dependent Ca2+ and crossbridge kinetics. Furthermore, the impact of diastolic stretch on sarcoplasmic reticulum (SR) Ca2+ handling was investigated. Axial cell stretch increased SR Ca2+ leak, but also and re-uptake of Ca2+ into the previously depleted SR of ventricular cardiomyocytes isolated from Guinea pig. The results were reproduced in model simulations. Axial stretch furthermore caused an acute increase in the Ca2+ spark rate of rat myoeytes. The mechanisms underlying this stretch-induced increase in spark rate act locally, are independent of nitric oxide and stretch-activated ion channels, and require an intact cytoskeleton. In conclusion, this thesis revealed that the interaction between cellular mechanics and Ca2+ handling is an important factor for integrative function of the heart, established several hitherto unknown mechanisms, and provided a novel set of experimental and theoretical tools for further research.
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Frain, Jennie. "The effects of mechanical load on human intervertebral disc cells." Thesis, University of Manchester, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493463.
Повний текст джерелаАнотація:
The precise mechanisms by which human intervertebral discs (IVD) respond to load remains unknown and are a challenge to investigate in vitro. In this study, a novel mechanical loading system was devised, built, tested and successfully used to apply hydrostatic pressure to nucleus pulposus (NP) and annulus fibrosis (AF) cells and explants obtained from human nondegenerate and degenerate IVD. Cells were removed from the IVD, cultured in monolayer to generate sufficient numbers and subsequently embedded in alginate constructs prior to application of dynamic cyclic hydrostatic pressure at physiological levels.
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Schmidt, Daniel. "The Effects of Cognitive Load and Stereotyped Groups on Punitiveness." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1438.
Повний текст джерелаАнотація:
The current study explores the interactions of cognitive load and stereotypes on emotions felt toward stereotyped groups and decisions of punitiveness for a crime. Dual processing models suggest that cognitive load can decrease deliberation and increase intuitive and emotional judgments. The Stereotype Content Model suggests that different stereotyped groups evoke different emotions. The current study tested the hypothesis that individuals under high cognitive load will be more likely to rely on stereotypical information and associated emotions when making decisions on punishment for a crime. Study 1 had 205 participants from Amazon’s Mechanical Turk website complete an online survey in which they read a vignette about an elderly man, a man who receives welfare checks, or a neutrally described man, who commits a “hit and run” crime. Half of the participants were then put under cognitive load, and all participants completed questions on punitiveness for the character’s crime, emotions felt towards the character, and perceptions of warmth and competence in the character. Study 2 repeated the manipulations and measures of study 1 with a few changes and in a college lab setting. Results were inconclusive in both studies and the null hypothesis was retained. Methodological and theoretical reasons for these results are discussed.
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Lynch, Erin E. "Effects of Perceptual Load on Dichotic and Diotic Listening Performance." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1627041542562664.
Повний текст джерела
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Lynch, Erin E. "Effects of Perceptual Load on Dichotic and Diotic Listening Performance." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1627041542562664.
Повний текст джерела
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Mohammed, Abdul Waheed. "Effects of Axial Component of Prestress in Load Balancing Method." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/802.
Повний текст джерелаАнотація:
Post-Tensioned concrete structures can be analyzed using different methods. One of these methods is the load balancing method introduced by T. Y. Lin. This method, unlike conventional stress methods, assumes pre-stress as a form of loading that counteracts the dead loads, live loads and service loads. Basically, the prestressing force is resolved into vertical and horizontal components and then the structure is analyzed as an ordinary loaded structure. The aim of this study is to investigate the effect of horizontal component of prestressing force in frames of different lengths. The horizontal component in beam-like structures will not affect the vertical reactions of the supports or bending moments of the beam. However, neglecting this component in frames can cause significant difference in the actual results. SAP2000 was used to analyze the frames by applying prestress forces directly and then by using balancing loads with and without considering the horizontal component of the prestressing force.
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Flodgren, Gerd. "Effects of low-load repetitive work and mental load on sensitising substances and metabolism in the trapezius muscle." Doctoral thesis, Umeå : Idrottsmedicin Sports Medicine, Rehabiliteringsmedicin Rehabilitation Medicine, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1393.
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20
Shope, Ronald L. "Response of Wide Flange Steel Columns Subjected to Constant Axial Load and Lateral Blast Load." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29521.
Повний текст джерелаАнотація:
The response of wide flange steel columns subjected to constant axial loads and lateral blast loads was examined. The finite element program ABAQUS was used to model W8x40 sections with different slendernesses and boundary conditions. For the response calculations, a constant axial force was first applied to the column and the equilibrium state was determined. Next, a short duration, lateral blast load was applied and the response time history was calculated. Changes in displacement time histories and plastic hinge formations resulting from varying the axial load were examined. The cases studied include single-span and two-span columns. In addition to ideal boundary conditions, columns with linear elastic, rotational supports were also studied. Non-uniform blast loads were considered. Major axis, minor axis, and biaxial bending were investigated. The effects of strain rate and residual stresses were examined. The results for each column configuration are presented as a set of curves showing the critical blast impulse versus axial load. The critical blast impulse is defined as the impulse that either causes the column to collapse or to exceed the limiting deflection criterion.
A major goal of this effort was to develop simplified design and analysis methods. To accomplish this, two single-degree-of-freedom approaches that include the effects of the axial load were derived. The first uses a bilinear resistance function that is similar to the one used for beam analysis. This approach provides a rough estimate of the critical impulse and is suitable only for preliminary design or quick vulnerability calculations. The second approach uses a nonlinear resistance function that accounts for the gradual yielding that occurs during the dynamic response. This approach can be easily implemented in a simple computer program or spreadsheet and provides close agreement with the results from the finite element method.Ph. D.
21
Wright, Adam Thomas. "The effects of cytoskeletal disruption and mechanical load on cardiac conduction." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3404478.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of California, San Diego, 2010.Title from first page of PDF file (viewed June 10, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (leaves 110-122).
22
Stephens, Marilee Jane. "The effects of load on normal, infant and Parkinsonian human gait." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0014/NQ59676.pdf.
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Chiesa, Luisa. "Mechanical and electromagnetic transverse load effects on superconducting niobium-tin performance." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53261.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 233-238).
Cable-in-Conduit Conductor is the typical geometry for the conductor employed in superconducting magnets for fusion applications. Once energized, the magnets produce an enormous electromagnetic force and very large transverse loads are applied against the strands. This large force results in a degradation of the performance of the superconducting magnets. In this thesis work transverse load experiments on sub-sized cables, have been designed to study the mechanical and electrical transverse load effects on superconducting cables. Two devices to apply external mechanical loads to a cable have been developed and several different size cables have been tested simulating the International Thermonuclear Experimental Reactor (ITER) Lorentz stress conditions. The first device was designed to use a circular turn sample of a 36-strand cable. Four samples were successfully tested with this device and significant degradations of the critical current due to the external transverse loads have been measured. However, all samples showed unexpectedly large initial degradations that made an analysis of transverse load effects of the samples difficult. The second device was developed for a hairpin configuration. Three different size cables of a single strand, a triplet and a 45-strand cable were systematically tested using this method. This hairpin sample device has successfully operated and provided very reliable experimental data. The experimental results were difficult to explain by existing theories.
(cont.) A new model based on contact mechanics concepts has been developed to determine the number of contacts and the effective contact pressure among the strands in a cable. The model was used to analyze and accurately calculate the displacements of a cable under transverse mechanical load, and it has evaluated the effective contact pressures between strands for the first time. The new model can explain the Lorentz force and contact pressure distribution effect on the critical current degradation of the tested samples. The 3-strand data and their critical current behavior as a function of the effective contact pressure were used to predict the test behavior of a 45-strand cable. It was also used to simulate the critical current degradations of various cables including ITER full size cables. The model has predicted an initial degradation of 20% for an ITER TF cable of 1152 strands at 68 kA operational current caused by the transverse Lorentz load effect only. Parametric studies of the model have indicated that the initial degradation could be reduced by shortening the twist pitch length of the initial stages of a full size cable or by mechanically supporting the last stage bundles of the cable. This thesis work shows for the first time, that the transverse Lorentz load effect, which is inherent in the CICC design, contributes a significant fraction of the degradation of a large Nb3Sn superconducting cable. The model quantifies the degradation and this information could be used in better estimating the appropriate margin requirements in magnet design.
by Luisa Chiesa.
Ph.D.
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Ghahghaeinezamabadi, Saeideh. "The dynamics of attention in active reading and effects of load." Thesis, Goldsmiths College (University of London), 2013. http://research.gold.ac.uk/9697/.
Повний текст джерелаАнотація:
We investigated the dynamics of spatial attention in an active viewing task, namely reading, and the effects of the load of target words on these dynamics. We showed that, over the course of a fixation, attention was modulated by the load of the fixated word and the upcoming word. The load of words was manipulated by varying word frequency and the orthographic familiarity of the first trigram in words. In a variation of the dynamic-orienting paradigm (Fischer, 1999), participants read sentences or strings of words for the primary task and discriminated gaze-contingent probes - occurring with variable spatial and temporal offsets from the first fixations on words - for the secondary task. Reading was evidenced by longer fixation durations on words with lower frequencies. The accuracy of probe discrimination was used to index attention. Early in a fixation, attention was focused on the gaze more when the fixated word was lower in frequency. This early effect of frequency was revealed for reading sentences and strings of words provided words were previewed before being fixated. Attention defocused over time and, by halfway through a fixation, orienting towards the to-be-fixated location (i.e., towards the right) began. Late in a fixation, attention had oriented more to the right of the gaze for high- than low-frequency words. Shortly before the saccade to the upcoming word, and during preview of this word, its processing was sufficiently advanced to affect attention: specifically, less attention remained at the gaze location when the first trigram of the upcoming word was orthographically less familiar. In sum, we showed that the moment-to-moment processing load of words affects the dynamics of spatial attention.
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Smith, William A. "Teaching Object-Oriented Programming with Modeling Tools: Effects on Cognitive Load." NSUWorks, 2002. http://nsuworks.nova.edu/gscis_etd/848.
Повний текст джерелаАнотація:
In order to assist learners with object-oriented programming and design principles, many types of visual modeling tools have been developed to demonstrate otherwise abstract concepts. Although businesses and educational institutions alike have embraced the most mature of these tools, the Unified Modeling Language (UML) notation, it has not been demonstrated that such graphical aids can equally facilitate learning and achievement by all individuals regardless of their prior experience with procedural programming languages. Other visual modeling aids that similarly integrate textual explanations with graphical models have been demonstrated in other studies to increase the cognitive load of learners and to negatively impact the effectiveness of the instruction when used with learners who possess high prior experience in a related area. The goal of this research was to determine the appropriateness of the use of UML modeling tools with students who possess high prior experience in a conceptually different area of programming and design. Specifically, this research examined the effects that teaching object-oriented programming and design with visual UML object modeling tools had on the cognitive load and achievement of experienced procedural programmer’s enrolled in a C++ programming class. Data for this study were collected from four sections of the Introduction to C++ classes at Tulsa Community College. Data were collected on the participants during the experimental semester by using a student programming self-efficacy survey and a series of four object-oriented programming and design achievement tests. On each test, students were asked to subjectively evaluate their cognitive load for the material covered by each question.
The data were analyzed for any significant interactions among the student's prior experience with procedural languages, their exposure to UML, their cognitive load, and achievement. It was expected that the results would show a significant negative relationship between the student's prior experience and their level of achievement when exposed to UML content in the classroom. However, due to multiple violations of tile assumptions of the statistical tests outlined in this study, the results of this study could only be descriptively analyzed. The descriptive analysis revealed only small differences in the levels of achievement and cognitive load among the study's population.
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Brown, Morgan E. "Effects of Age, Task Type, and Information Load on Discrimination Learning." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1648.
Повний текст джерелаАнотація:
The feature positive effect (FPE) is a phenomenon in discrimination learning by which learning occurs more quickly when the presence (Feature positive; FP), rather than absence (Feature negative; FN) of a stimulus indicates a response should be made. Although the FPE has been extensively corroborated, a reversal, or feature negative effect (FNE), has been found when a target stimulus comes from a smaller set of stimuli (Fiedler, Eckert, & Poysiak, 1988). Age differences in FP and FN learning indicate that older adults perform more poorly than young adults on both FP and FN tasks, and are likely related to decline in working memory (WM) throughout adulthood (Mutter, Haggbloom, Plumlee, & Schrimer, 2006). This study used a successive discrimination task to compare young and older adults’ performance across FP and FN conditions under low (three of a set of four stimuli were presented) and high (three of a set of six stimuli were presented) information load (IL). Results from rule articulation, final incorrect and 12 consecutive trials correct did not support the hypotheses, but trend analyses provided partial support. Under low IL, YA demonstrated a FN response bias whereas OA showed no bias. Under high IL, YA and OA demonstrated equivalent performance whether the target stimulus was present or absent in the FP condition. In the FN condition OA performed better when the target stimulus was absent while YA showed no bias. These findings indicate FN task performance varies by age and this variation changes based on IL condition.
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Dahlgren, Emma. "Effects of Different Load Magnitudes on Longitudinal Growth of Immature Bones." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230885.
Повний текст джерелаАнотація:
In vivo studies of mechanical loading on bone have suggested that load magnitude is one of the parameters that play a vital role in bone adaptation. This study examined how longitudinal growth of immature rat metatarsals is affected by different load magnitudes. The main hypotheses were that the longitudinal growth of immature bone would decrease with increased compressive load magnitude, and that the longitudinal growth would be more decelerated the higher the load mag- nitude. The three middle metatarsal bones in the back paws of 19-20 days old Sprague-Dawley rat fetuses were extracted. Metatarsal bones were loaded with 0.05 N, 0.25 N, 1.25 N and 6.25 N. Loading rate and number of cycles were constant at 0.01 mm/sec and 10 cycles respectively. Length measurements occurred every 2-3 day. Concluded from the study was that a load magni- tude of 0.05 N resulted in an increased longitudinal growth, compared to unloaded bones. For the other load magnitudes the results were insufficient and inconsistent and therefore nothing could be suggested for them. The problem remained as before and further studies are needed.
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Bialko, Christopher Stephen. "The Effects of Practice and Load on Actual and Imagined Action." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1242884385.
Повний текст джерела
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Yaiaroon, Niphan. "Probabilistic modelling of extreme traffic load-effects based on WIM data." Thesis, The University of Sydney, 2009. https://hdl.handle.net/2123/28224.
Повний текст джерелаАнотація:
The primary aims of this thesis are to develop a realistic probabilistic model of extreme
traffic load-effects (referred to as a Probabilistic Model), which could be used for a
reliability—based assessment of the safety of existing bridges, and to develop a model
that provides an efficient approximation (without significant computational difficulties)
for the Probabilistic Model (referred to as an Approximate Model). The research
focuses on the analysis of traffic load-effects estimated from Weigh-in-Motion data by
calculating hypothetical load-effects that would be induced by each vehicle.
Considerations are given to single-span simply—supported and typical three—span
continuous bridges with main span lengths up to 40 m, and the load—effect results are
used as the basis for calibrating realistic probabilistic models proposed in this research.
A preliminary assessment scheme is developed to determine the quality of WIM
data, including a rational method to assist in accepting or rejecting daily data records. A
key feature is to inspect the data for consistency of the average daily single steer axle
mass distributions for selected vehicle patterns. Visual inspection of graphs of statistical
distributions is also essential for WIM data with significant temporal variations. The
site-specific traffic characteristics for each WIM site that can be derived from the
obtained WIM data are examined and presented.
A simulation study on theoretical static peak load-effects given by the obtained
WIM data was conducted in order to analyse frequency distributions of normalised peak
load-effects, normalised with respect to ‘characteristic values’. For peak load—effects
normalised with respect to the corresponding 99th percentile peak load-effects (as
characteristic values), it was found in general that the extreme normalised peak loadeffect
distributions (exceeding the load-effect thresholds) were essentially the same for
all load-effects. The peak load-effects normalised with respect to the corresponding
peak load-effects given by the T44 design load were also examined and it was found
that the T44 design load did not provide a good representation of the critical vehicles for
the traffic loads considered.
A Probabilistic Model that can be used effectively to approximate all
distributions of extreme normalised peak load-effects is developed to describe the
distributions given by general vehicles. The Probabilistic Models include an upper limit
on the maximum load-effect, and the models were validated by comparing with the
distributions of theoretical load-effects obtained from the WIM data. Furthermore, for
selected cases, they were also compared with extrapolations of extreme normalised peak
load—effects based on approximate Normal probability distributions. The resultant
distributions show that the Probabilistic Models provide an efficient basis to
approximately describe the distributions for WIM data without a large proportion of
heavily overloaded C10 (1-2-2-2) vehicles.
An example is provided for a case in which the extreme normalised peak loadeffect
distribution is not accurately described by a Normal probability distribution,
whereas sufficient accuracy is provided by a Probabilistic Model calibrated specifically
for this load-effect distribution. Extreme value distributions corresponding to sample
sizes of 1 million and 100 million vehicles were derived from the Probabilistic Models
and the Normal probability approximations for selected cases, and differences between
these extreme value distributions were inspected to study the effect of the upper limits
of the Probabilistic Models.
Finally, validation of the Approximate Models was carried out for selected cases
by comparing with the Probabilistic Models and the distributions obtained from WIM
data. An approximate threshold value for the Approximate Model is given by a
characteristic truck model capable of predicting the threshold values for all load-effects.
This truck model is based simply on the GVM information fiom the WIM data.
Satisfactory results were obtained from the characteristic truck model for describing
threshold values for all bridge types and all load-effects, using a very simple method,
and the threshold value estimation was most accurate for bridges with long main span
lengths.
The accuracy of the Approximate Model depends on the accuracy of the
characteristic truck model to estimate the threshold values. For selected cases, it has
been found that the Approximate Models provide an efficient and reasonably accurate
basis to approximate the distributions obtained from WIM data and the detailed
Probabilistic Models developed in this research.
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Blumer, Tyler D. "Carton Clamp Methodologies and the Effects on Load Containment and Retention." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1150.
Повний текст джерелаАнотація:
ABSTRACT
Carton Clamp Test Methodologies and the Effects on
Load Containment and Retention
Tyler Don Blumer
A carton clamp is an alternative device for moving packages and material. Instead of using iron tines like that of a conventional forklift, a carton clamp uses two large aluminum platens to slightly compress and secure the load for handling. This is advantageous as it allows operators to move layers of a unitized load individually, and eliminates the need for a pallet when handling full unitized loads. When using a carton clamp attachment, it is often difficult for operators to accurately gauge the amount of force being applied to the load. The required clamping force changes depending on the size, shape, and weight of the load. This creates the potential for under-clamping (slippage) and over-clamping (compressive damage). Seeing a market need for a reliable means of testing, two organizations set out to develop a testing protocol.
A rift formed between schools of thought regarding the correct testing procedure. ISTA provides a sterile, calculated, and stationary simulation of carton clamp handling in its ISTA 6-SAMS test protocol. ASTM offers a more holistic, dynamic, observational approach in its mobile ASTM 6055 standard protocol. One school of thought is suggested to imply that a package should be developed to be handled by the carton clamp (ASTM). The other school of thought is that the carton clamp attachment should be properly adjusted to the package specimen (ISTA).
Previous studies have been performed citing the ISTA standard and using a specialized carton clamping device vibration device that is calibrated for laboratory research. Arguably, this method, though repeatable in nature, does not accurately simulate carton clamp handling found in industry. Likewise, the equipment investment is cost prohibitive for those in industry wishing to duplicate such a study. ASTM uses a carton clamp truck as used in industry, but does not specify any specific parameters making repeatability between laboratories and practitioners ambiguous.
This study examined whether or not a common ground can be reached; implementing a carton clamp lift truck as found in industry allowing for mobile (hazard course) testing. A modified version of ISTA 3B will be paired off against ASTM 6055 for evaluating both column and cross stack pallet patterns with a variety of treatments. This study attempted to determine if carton clamps as found in industry are capable and repeatable enough to provide consistent data. Similarly, this study examined the test methodologies effect on load containment via stretch film force, load retention via unitized load slippage, and the effects of ride height and driver interaction. The study sought to understand if these effects are uniform across the unitized load, or if particular layers of the load more affected than others.
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Sass, Kelly J. "Use of the isolated elements effect to teach observational gait analysis : the effects on cognitive load and learning outcomes." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/3181.
Повний текст джерелаАнотація:
The analysis of human walking gait is a complex skill for physical therapy students to learn. As a result, students are at risk for a cognitive overload when confronted with these materials. Cognitive load consists of both intrinsic and extraneous loads as well as the germane processes that are required by the learners to process the information in working memory. As working memory is limited in its capacity to process new information, it is necessary to manage the cognitive load experienced by the learners. Intrinsic cognitive load is related to the complexity of the materials that must be learned and cannot be altered by instructional design without sacrificing initial understanding. An isolated elements instructional format purports to reduce the intrinsic CL experienced by learners by isolating the content into the individual elements prior to introducing any complex relationships that may exist between the elements. The purpose of this study was to examine the cognitive load and learning outcome effects of an isolated elements instructional format versus an interacting elements format when teaching observational gait analysis to physical therapy students.
A total of 72 students enrolled in a Doctor of Physical Therapy program participated in this study. Mixed factorial designs assessed both between-group and within-group outcomes. The independent variables were the group assignments (isolated or interacting) and time. The dependent variables were cognitive load and learning outcomes. Cognitive load was measured with 7-point Likert-type scales for both mental effort and task difficulty at five separate time points. Learning outcomes were assessed through performance scores and confidence ratings on a posttest and a 1-week follow-up test. Animated videos were used as the medium for instructional delivery. In the isolated elements group, the learners received the content in several separate videos that isolated each of the sub-phases of gait prior to viewing a summary video that included all of the interacting gait cycle components. Learners in the interacting elements group received the content in one video that included the full gait cycle followed by the same summary video.
Students in the isolated elements groups reported lower mental effort ratings immediately after viewing the isolated elements videos than did the interacting group after viewing the single video tutorial. However, there was no differences in either mental effort or task difficulty ratings at the other time points during the lesson or during the assessments. Performance scores and confidence ratings did not differ between the two groups. Within-group analyses found that there were significant changes over time in both groups for mental effort, performance scores, and confidence ratings. A statistically significant change was noted over time for task difficulty in the interacting elements group. The reduction in mental effort ratings immediately following the tutorial content for the isolated elements group lends support the theory that isolating the individual elements prior to teaching the complex interactions can reduce cognitive load for learners. However, this reduction in cognitive load did not translate into improved test scores or confidence compared to the interacting elements group. Future research is needed to identify instructional methods that can further reduce the cognitive load and increase the learning outcomes of students learning observational gait analysis. In addition, alternative objective methods of assessing cognitive load should be explored.
32
Patterson, M. J. "Gender and physical training effects on soldier physical competencies and physiological strain." Fishermans Bend, Vic. : Defence Science and Technology Organisation, 2005. http://hdl.handle.net/1947/4680.
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Zhou, Chao Ying. "Effects of combination motions on cylinders in waves and currents." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339445.
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34
Cunningham, Ronald. "Effects of joint continuity on tapered member steel portal framed structures." Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1051.
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35
IWASE, Satoshi, Qi FU, Kenichi NARITA, Eiichi MORIMOTO, Hiroki TAKADA, and Tadaaki MANO. "Effects of Graded Load of Artificial Gravity on Cardiovascular Functions in Humans." Research Institute of Environmental Medicine, Nagoya University, 2002. http://hdl.handle.net/2237/2775.
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36
Khan, Imran. "Effects of hydraulic load on nitrate removal in surface-flow constructed wetlands." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15148.
Повний текст джерелаАнотація:
Abstract Constructed wetlands had been widely used as economical and environment friendly treatment systems for agriculture runoff in southwest Sweden to limit the transport of nutrients to Kattegat, thereby aiding in the effort of abating eutrophication. The extensive use and acceptance of wetlands as treatment systems had been an incentive to develop performance models. Even recent studies showed that first order models are inadequate to guide the design of constructed wetlands, these are still commonly used. The main assumption of such models is tested here, which states that the removal rate of pollutant(s) is proportional to concentration in a constructed wetland. For this purpose experimental wetlands in Plonninge near Halmstad (southwest of Sweden) were selected and divided into two groups (9 each). They were fed with different hydraulic loads achieving 4 and 8 days residence times. The data obtained from the analysis of total nitrogen and nitrate were tested with first order equations and found that these models are sufficient to describe the nitrate removal in nitrate rich experimental wetlands. Key words: constructed wetlands, hydraulic load, first order kinetic models, eutrophication, nitrogen removalAbstrakt Anlagda våtmarker har i stor utsträckning använts så ekonomisk och miljövänlig behandling av system för jordbruk avrinning i sydvästra Sverige för att begränsa transporten av näringsämnen till Kattegatt och därmed hjälpa till i ansträngningarna på att avta övergödning. Den omfattande användningen och acceptansen av våtmarker som behandling systemen hade ett incitament att utveckla prestanda modeller. Även senare studier visade att första order modellerna är otillräckliga för att vägleda designen av konstgjorda våtmarker är dessa fortfarande vanliga. Det viktigaste antagandet om sådana modeller testas här, som säger att avverkning av föroreningar (s) är proportionell mot koncentrationen i en konstruerad våtmark. För detta ändamål experimentella våtmarker i Plönninge utanför Halmstad (sydväst om Sverige) valdes ut och delades i två grupper (9 vardera). De matades med olika hydrauliska belastningar uppnå 4 och 8 dagar uppehållstid. De data som erhållits från analysen av totalkväve och nitrat testades med första ordningens ekvationer och fann att dessa modeller är tillräckliga för att beskriva nitrat bort i nitrat rika experimentella våtmarker. Nyckelord: anlagda våtmarker, hydraulisk belastning, första ordningens kinetiska modeller, övergödning, kväverening
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Lok, Gordon Tat Kwong. "Load induced microcracking and its effects on the air permeability of mortar." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28834.pdf.
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Peters, Sean Michael. "The effects of LCAC load policy on the duration of amphibious assault." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28146.
Повний текст джерелаАнотація:
Approved for public release, distribution is unlimitedA deterministic analytical model of LCAC operations is developed, based on the assumption that the mean time required to load the LCAC is an exponential function of the load weight. Simulation models of single queue and multiple queue LCAC operations are developed and the results compared to the deterministic model. Good agreement is obtained between the models. The results show that for most scenarios, the minimum time to complete the offload occurs for load sizes less than 60 tons
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Schade, Andrew. "Lying Behavior| The Effects of Dual-Task Performance and High Cognitive Load." Thesis, The Chicago School of Professional Psychology, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3684159.
Повний текст джерелаАнотація:
Lying is sometimes more difficult than telling the truth because it requires more cognitive resources or "cognitive load." Implementing high cognitive load has been suggested to help facilitate the observation of deceptive behavior. Research suggests that people can correctly judge when individuals are lying only about 50% of the time when observing their nonverbal behavior. Individuals tend to restrict movements in their legs and feet when they are lying, perhaps in an effort to avoid giving off any nonverbal cues that might be interpreted as possible guilt. In the current study, it was hypothesized that participants would have significantly less movement in their legs and feet when lying than when telling the truth, as measured by total duration of time. Fifty-five participants were recruited from the University of California, Irvine and The Chicago School of Professional Psychology at Irvine. Participants were asked to respond to a total of 4 questions, in which 2 of their responses were truths and 2 were lies. They simultaneously played a game on a computer with the intent to increase cognitive load and decrease available cognitive resources to create a believable lie. Analyses of data were conducted using repeated-measures ANOVA. The results revealed some significant differences in the amount of time participants moved their lower body, but for only 1 of the lie questions. The results of the study support the idea that more research is needed to determine how to detect deception via nonverbal behavior more accurately, especially when implementing high cognitive load.
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Trawley, Steven. "Prospective memory benefits from contextual support : differential effects of working memory load." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441039.
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Chastain, Patrick Alan. "Effects of load proportioning on the capacity of multiple-hole composite joints." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90922.
Повний текст джерелаАнотація:
This study addresses the issue of adjusting the proportion of load transmitted by each hole in a multiplehole joint so that the joint capacity is a maximum. Specifically two-hole-in-series joints are examined. The results indicate that when each hole reacts 50% of the total load, the joint capacity is not a maximum. One hole generally is understressed at joint failure. The algorithm developed to determine the load proportion at each hole which results in maximum capacity is discussed. The algorithm includes two-dimensional finite-element stress analysis and a failure criteria. The algorithm is used to study the effects of joint width, hole spacing, and hole to joint-end distance on load proportioning and capacity. To study hole size effects, two hole diameters are considered. Three laminates are considered: a quasi-isotropic laminate; a cross-ply laminate; and a 45 degree angle-ply laminate. By proportioning the load, capacity can be increased generally from 5 to 10%. In some cases a greater increase is possible.M.S.
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Bonath, Leah M. "The Effects of Cognitive Load on the Perception of Foreign-Accented Words." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu1461938923.
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Hurrell, Michael J. "Shroud Effects on Load-independent Power Loss of High-speed Rotorcraft Gearing." Cleveland State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=csu1588885945866605.
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D'Elia, Samuel C. "The spray/load and dative alternations : aligning VP structure and contextual effects." Thesis, University of Kent, 2016. https://kar.kent.ac.uk/54773/.
Повний текст джерелаАнотація:
The theoretical and experimental work presented in this thesis investigates the spray/load and dative alternations. The purpose is to provide a comprehensive analysis of the alternations in terms of their syntactic structures and to account for how contextual information drives differences in the linear order of their VP arguments. This analysis shows that the syntactic structures of the spray/load and dative alternations are identical; each variant in an alternation is characterised by one of two available structures proposed in Janke and Neeleman (2012). Each structure is shown to respect a novel thematic hierarchy that is based on the value of binary feature clusters (Reinhart, 2000) rather than by direct reference to semantic labels. The choice of a particular structure is demonstrated to be affected by the non-semantic context in which the spray/load or dative sentence is generated. This is a consequence of the limited processing capacity of Working Memory and the allocation of attentional resources to a stimulus. Experimental data from an as yet untested variable of the visual context – the egocentric perception of distance – is found to interact with word order preferences of the alternations. I conclude that non-semantic contextual information interacts with the encoding of an event which ultimately has consequences for syntactic choices.
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McMaster, Fraser J. "The effects of load interaction on fatigue crack growth and crack closure in aluminium alloys." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297844.
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Colin, Julie Anne. "Deformation History and Load Sequence Effects on Cumulative Fatigue Damage and Life Predictions." University of Toledo / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1260390033.
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Lancaster, Gary Lee Joseph. "The effects of dual-task interviews on cognitive load and cues to deception." Thesis, University of Portsmouth, 2011. https://researchportal.port.ac.uk/portal/en/theses/the-effects-of-dualtask-interviews-on-cognitive-load-and-cues-to-deception(9867c9a3-ea7d-48b7-8814-0e8a3ae83b5d).html.
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This thesis used a ‘cognitive load plus’ approach to explore whether deliberate interventions, (e.g. secondary tasks and unanticipated interview questions) would (i) affect liars and truth tellers cognitive load differently during an interview and (ii) lead to differences in behaviour between liars and truth tellers which could be used to detect deception. Chapter 1 provides a brief introduction to the cognitive load approach to detecting deception and the growing body of research in this area. Next, Experiment 1 is reported in which a computer based target tracking secondary task was performed by (N = 45) lying and (N = 45) truth telling interviewees while they responded to an interviewer’s questions about a mission briefing they were given prior to being interviewed. Truth tellers described their true mission to the interviewer whereas liars gave a fictitious cover story. The main findings, supportive of the cognitive load approach, were that (i) liars made significantly less frequent eye-contact with the interviewer than truth tellers and (ii) liars’ behaviour was rated differently to truth tellers by an independent observer. However, against prediction, there were no differences between liars and truth tellers in terms of their computer task performance or in the numbers of details provided in their verbal statements. These findings informed the design of Experiment 2A which examined the effect of asking unanticipated interview questions on lie detection. In an activity room truth tellers (N = 40) performed five simple tasks (e.g. pairing up playing cards). Liars (N = 40) observed the activity room through a window and were asked to generate a story in which they would claim to have performed five tasks. The interview schedule included four thematically related pairs of questions. The first question of each pairing was easy for interviewees to anticipate as it reflected how events are typically recalled (e.g. in normal chronological order). The second question included a perspective shift (temporal or spatial), which made the question harder for interviewees to anticipate (e.g. recalling the event in reverse order). Eye-gaze was also manipulated by asking half the interviewees to maintain constant eye-contact with the interviewer. Lastly, interviewees’ performed an object sorting secondary task while answering the interview questions. Compared to truth tellers, liars’ verbal responses showed a greater net decline in details, (termed Verbal decline), across three out of four question pairs. Liars also sorted significantly fewer objects per minute on the secondary task. However, there was no relationship between eye-gaze and veracity. In Experiment 2B, 80 observers each saw a single edited video clip of either a liar or truth teller answering one pair of Expected/Unexpected questions from Experiment 2A. Observers were instructed to make a veracity judgment while focussing only on the presence or absence of Verbal decline in the interviewee’s statement. Observers’ accuracy for detecting deception was compared with accuracy rates obtained from a discriminant analysis of the manually coded Verbal decline in Experiment 2A. Observers identified liars with 65% accuracy which compared favourably with the 67.5% accuracy of manual coding. However truth tellers were identified by observers with 60% accuracy which was significantly below the 82.5% rate of manual coding. Experiment 3 retained the sorting task, eye-gaze manipulation and activity room scenario from Experiment 2A while introducing three new pairings of Expected/Unexpected interview questions and two further unpaired questions requiring interviewees to (i) estimate the durations of two tasks they claimed to have completed and (ii) to suggest a future task completion strategy for one task they claimed to have performed in the activity room. Once again liars sorted significantly less correct objects per minute than truth tellers and there was a partial replication of the Experiment 2A findings for Verbal decline. For the new questions: liars showed greater Verbal decline than truth tellers on one of the three new question pairings and liars were significantly less accurate than truth tellers at estimating duration. However, against prediction, liars’ suggested task strategies did not differ in complexity from truth tellers and again there was no relationship between eyegaze and veracity. Overall, the present thesis’ findings were largely supportive of the theory that lying can be more cognitively demanding than truth telling and that monitoring secondary task performance provides an objective measure of an interviewee’s cognitive load. Also it was demonstrated that strategic use of perspective shifted interview questions elicited a cue (Verbal decline) which could be used to detect deception. The practical and theoretical implications of the present experiments are discussed in a final chapter.
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Lam, Sze Yue. "Effects of axial load, shielding and shape on negative skin friction on piles /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202006%20LAM.
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Wood, Melisa. "Stereotype use in person perception : interaction effects between prejudice level and cognitive load /." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09ARPS/09arpsw8732.pdf.
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Wang, Bing. "Duration-of-load and creep effects in thick MPB strand based wood composite." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23906.
Повний текст джерелаАнотація:
British Columbia (BC) is in the midst of the largest outbreak of the Mountain Pine Beetle (MPB) ever recorded in western Canada. Technologies capable of converting stained lumber into market acceptable products are urgently required to reduce the impact of the growing volume of MPB killed lumber on the profitability of forestry in BC.
New, thick MPB strand-based structural composite products can be produced and help absorb a large volume of MPB wood. With appropriate mechanical properties, such products can be used as beams, headers, and columns in the low-rise commercial, multi-family residential and single family residential markets.
This work was focused on the duration-load and creep behaviour of thick MPB strand-based wood composite. The beam specimens were made in the Timber Engineering and Applied Mechanics Laboratory at UBC. A series of tests were conducted on the matched groups to investigate the creep-rupture behaviour. These investigations comprised of ramp load tests at three loading rates, long-term constant load tests at two stress levels and cyclic bending tests at six stress levels.
A damage accumulation model was developed to study the creep-rupture behaviour. This model stipulates that the rate of damage growth is given in terms of the current strain rate and the previously accumulated damage, and a 5-parameter rheological model is applied to describe the viscoelastic constitutive relationship to represent the time-dependent strain, while the damage accumulation law acts as the failure criterion. The results of the long-term constant load tests were then interpreted by means of the creep-rupture model which had been shown to be able to represent the time-dependent deflection and time-to-failure data for different stress levels. The predictions of the model were verified using results from ramp load tests at different loading rates and results from cyclic loading tests at different stress levels. The creep-rupture model incorporates the short term strength of the material, the load history and predicts the deflection history as well as the time-to-failure. As it is a probabilistic model, it allows its incorporation into a time-reliability study of wood composites’ applications.