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Experimental and Computational Study of Intraglottal Pressure Distributions for Vocal PolypsRahiminejad Ranjbar, Leila 19 December 2018 (has links)
No description available.
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Investigation and Analysis of the Effect of Industrial Drums and Plastic Pails on Wooden Pallets throughout the Supply ChainAlvarez Valverde, Mary Paz 05 October 2021 (has links)
In the supply chain there are three components: transportation method, the pallet, and the packaging. Traditionally, there has been a poor understanding of the way that pallet design can impact the supply chain. There are historical studies that illustrate the importance of investigating how box stacking pattern, unit load type, unit load size, and containment can impact the pallet's performance. However, there have been no studies that have investigated the impact of drums and plastic pails on pallet performance.
The goal of the current research study was to investigate how plastic pails and drums affect pallet bending and the distribution of the pressure on the top surface of the pallet. The investigation was conducted using four different support conditions commonly found in warehouses: racking across the width and length, single stacking, and double stacking. The results of the investigation indicated that for most support conditions, loading the pallet with plastic pails or drums results in a significant reduction in deflection when compared to a uniformly distributed load. The maximum observed reduction in pallet deflection was 85% when testing with drums in the double stack condition and 89% when testing with plastic pails in the single stack condition. The large reductions in deflection could indicate that the pallets were over-designed for the unit load that they were supporting.
Pressure mat distribution images collected during the experiment display a load bridging effect where the stress of the drums and pails are redistributed to the supported sides of the pallet. The data also show that drums made of different materials distribute the pressure onto the pallet in a significantly different manner. / Master of Science / Wood pallets are crucial to the supply chain that delivers the goods and objects that sustain our economy. Every product order or product that is seen in stores was sent through the supply chain. The supply chain is made up of three major interacting components, the material handling system, the packaging, and the pallet. By further understanding the interaction between these components, pallet and packaging designers can better utilize materials and maximize the efficiency of the supply chain.
There is a need to understand how different types of packages interact with the pallet to effectively design pallets and to potentially reduce costs and material usage. Historical studies focused on investigating how corrugated boxes affect pallet performance. They mainly focused on the effect of corrugated box size, flute type, stretch wrapping and containment, and the influences that pallet design have on pallet performance.
Past studies identified that packages on the top of the pallet could create a bridging between the packages that can reduce the stresses on the pallet and consequently increase its load capacity. By using this load bridging effect for their advantage, pallet designers can design pallets that are safer, cheaper, and be more environmentally friendly since current wood pallets are designed under the assumption of a uniformly distributed, rather than bridged, load.
The goal of the current study was to investigate how the load bridging effect created by pails and drum affects the deflection of the pallet in the floor stacked loading condition. The investigation was conducted using four different support conditions commonly found in warehouses such as racking across the length, racking across the width, single stacking, and double stacking. The results of the investigation indicated that for most investigated support conditions, the interaction between pails and drums causes an increase in load bridging which significantly reduces the bending of the pallet. The reductions reached a maximum of 85% when testing with drums in the double stack condition and 89% when testing with plastic pails in the single stack condition. The large reductions in deflection could indicate that the pallets were over-designed for the unit load that they were supporting.
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Quantitative Hydrodynamics Analysis of Left Ventricular Diastolic Dysfunction using Color M-Mode EchocardiographyStewart, Kelley Christine 18 November 2008 (has links)
Numerous studies have shown that cardiac diastolic dysfunction and diastolic filling play a critical role in dictating overall cardiac health and demonstrated that the filling wave propagation speed is a significant index of the severity of diastolic dysfunction. However, the governing flow physics underlying the relationship between propagation speed and diastolic dysfunction are poorly understood. More importantly, currently there is no reliable metric to allow clinicians the ability to diagnose cardiac dysfunction. There is a greater need than ever for more accurate and robust diagnostic tools with the increasing number of deaths caused by this disease. Color M-mode (CMM) echocardiography is a technique that is commonly used in the diagnosis of Left Ventricular Diastolic Dysfunction (LVDD) and is used as the image modality in this work.
The motivation for the current work is a hypothesized change in the mechanism driving early diastolic filling. The early filling wave of a healthy patient is driven by a rapid early diastolic relaxation creating a pressure difference within the left ventricle despite the fact the left ventricular volume is increasing. As diastolic dysfunction progresses, the left ventricular relaxation declines and it is hypothesized that the left atrial pressure rises to create the favorable pressure difference needed to drive early diastole. This changes the mechanism driving early diastolic filling from a pulling mechanism primary driven by left ventricular relaxation to a pushing mechanism primarily driven by high left atrial pressure.
Within this study, CMM echocardiography images from 125 patients spanning healthy and the three stages of LVDD are analyzed using a newly developed automated algorithm. For the first time, a series of isovelocity contours is utilized to estimate the conventional propagation velocity. A critical point within the early filling wave is quantified as the point of early filling velocity deceleration. The clinically used propagation velocity is compared to a novel critical point propagation velocity calculated as a weighted average of the propagation velocities before and after the critical point showing an increase in the correlation between decreasing diastolic dysfunction stage and decreasing propagation velocity. For the first time the spatial pressure distributions calculated as the pressure relative to the mitral valve pressure at each location from the mitral valve to the ventricular apex, are quantified and analyzed at the instant of peak mitral to apical pressure difference for patients with varying stages of LVDD. The analysis of the spatial pressure distribution revealed three filling regions present in all patients. The pressure filling regions were used to calculate a useful filling efficiency with healthy patients having a useful filling efficiency of 64.8 ± 12.7% and severely diseased filling patients having an efficiency of 37.1 ± 12.1%. The newly introduced parameters and analysis of the CMM echocardiography data supports the hypothesis of a change in the mechanism driving early diastolic efficiency by displaying a decline in the early diastolic propagation velocity earlier into the left ventricle for severely diseased patients than for healthy filling patients and a premature breakup of the progressive pressure gradient fueling early diastolic filling in severely diseased patients. / Master of Science
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A variação da profundidade em função do tempo, na saída de um canal retangular curto de declividade nula, após a abertura rápida de uma comporta / The variation of the depth versus time, at the exit of a short rectangular channel of zero slope, after the fast opening of a floodgateBarbosa, Elder Damião 31 March 2000 (has links)
O escoamento hidrodinâmico é descrito por meio das equações da continuidade e da quantidade de movimento em conjunto com as condições iniciais e de contorno. Neste trabalho de pesquisa, o escoamento não permanente na saída de um canal retangular curto de declividade nula, resultante da abertura rápida de uma comporta foi experimentalmente investigado. Para determinar o coeficiente de pressão e o comprimento do trecho a montante da comporta com distribuição de pressão não hidrostática, usou-se um modelo unidimensional, descrito pelas equações de Saint Venant, para representar o fenômeno. Utilizou-se o método de Lax-Wendroff para obter as curvas características do fenômeno e compará-las com os resultados obtidos experimentalmente. Várias comparações foram feitas possibilitando a avaliação de valores para os parâmetros que definem a região com distribuição de pressão não hidrostática. Os resultados calculados para os valores de parâmetros constantes, estão de acordo com os resultados experimentais. Os resultados experimentais ajustam-se melhor quando os valores dos parâmetros variam no decorrer do tempo. / The hydrodynamic flow is described by means of the equations of the continuity and momentum together with the initial conditions, the boundary conditions. In this research work, the unsteady flow at the exit of a short rectangular channel of zero slope, resulting from the fast opening of a floodgate was investigated experimentally. For determining the pressure coefficient and the length of the upstream reach of the floodgate with non-hydrostatic pressure distribution, a one-dimensional model described by Saint Venant equations is used to represent the phenomenon. The Lax-Wendroff method was used to obtain the curves characteristics of the phenomenon and to compare them with the results obtained experimentally. Several comparisons were made to facilitate the evaluation of values for the parameters that define the region with non-hydrostatic pressure distribution. The results calculated for the values of constant parameters are in agreement with the experimental results. The experimental results are better adjusted when the values of the parameters vary in elapsing of the time.
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Der Einfluss von übermäßigem Körpergewicht und einer verminderten kutanen Sensorik am Fuß auf die plantare Belastung beim GehenLange, Justin Sebastian 26 August 2014 (has links) (PDF)
Der menschliche Gang und damit auch das Abrollverhalten und die Belastungssituation des Fußes wird von einer Vielzahl an extrinsischen und intrinsischen Faktoren beeinflusst. In dieser Arbeit soll der Einfluss des Körpergewichtes, im Speziellen der übermäßigen Körpermasse unter der Krankheit Adipositas sowie der Einfluss der plantaren, kutanen Sensorik auf den menschlichen Gang betrachtet werden.
Die starken Auswirkungen von Übergewicht und Adipositas auf das muskuloskelettale System lassen sich vor allem an der hohen Prävalenz von Schmerzen an den unteren Extremitäten festmachen. Besonders häufig treten neben Schmerzen an Hüfte und Knie auch Beschwerden im Bereich des Fußes auf. Die Betrachtung kinetischer Auswirkungen von Übergewicht und Adipositas auf den Bewegungsapparat rückt daher zunehmend in den Fokus der bewegungswissenschaftlichen Forschung. Die aktuelle Studienlage lässt derzeit jedoch keine eindeutigen Schlussfolgerungen zu, in welcher Weise sich Adipositas mit steigendem Schweregrad auf das Gangmuster auswirkt. Besonders im Bereich des Fußes fehlen belastungsrelevante Informationen mit denen das Abrollverhalten des Fußes bestimmt und mögliche Fehlbelastungen erkannt werden können.
Zur Behandlung von schweren Graden der Adiposits werden adipositaschirurgische Maßnahmen eingesetzt. Dadurch ist es möglich in kürzester Zeit einen starken Gewichtsverlust hervorzurufen. Unklar ist, ob sich das Gangbild nach einem entsprechenden Gewichtsverlust wieder normalisieren kann und Adaptationsvorgänge nach einem längeren Zeitraum nachweisbar sind.
In zwei Studien soll daher das plantare Belastungsmuster unter Adipositas evaluiert werden. In Studie I wird dazu eine Kategorisierung nach dem Schweregrad der Adipositas vorgenommen und das plantare Belastungsmuster der jeweiligen Gruppen gegenüber dem einer normalgewichtigen Gruppe gestellt. Ein besonderes Augenmerk soll hier auf Belastungen im Fersen- und im Mittelfußbereich gelegt werden, da hier Schmerzen am häufigsten auftreten. Der Kenntnisgewinn aus dieser Studie soll vor allem zur theoretischen Herleitung der Entstehungsmuster von Schmerzen im Bereich des Fußes dienen, aber auch typische Gangmuster der einzelnen Adipositas Grade festhalten. In Studie II erfolgt die Betrachtung der plantaren Belastung nach einem adipositaschirurgischen Eingriff. Ziel dieser Studie ist es, Anpassungsprozesse nach einem massiven Gewichtsverlust im Gangverhalten zu bewerten und Faktoren, welche wesentlich zur Veränderung des Gangbildes beitragen, auszumachen. Die Ergebnisse können weiterhin Hinweise auf eine mögliche Notwendigkeit einer bewegungstherapeutischen Begleitung nach einem adipositaschirurgischen Eingriff liefern.
Studie III beschäftigt sich mit den Auswirkungen einer Desensibilisierung der plantaren kutanen Sensorik auf das plantare Abrollmuster beim Gehen. Die kutanen Mechanorezeptoren sind wesentlich an der posturalen Kontrolle beim Stehen und bei dynamischen Bewegungsvorgängen beteiligt. Beeinträchtigungen in der Funktionsweise der plantaren kutanen Mechanorezeptoren bspw. in Folge einer diabetischen Polyneuropathie können zu Gangpathologien, einer erhöhten Sturzgefahr oder auch der Entstehung von Druckulzerationen führen. Die Stärke der Beteiligung der plantaren Sensorik am plantaren Belastungmuster ist jedoch nicht ausreichend erschlossen und soll daher in Studie III betrachtet werden.
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Evaluation Methods for Friction Materials in a Four-Wheel Drive DrivetrainShahrezaei, Khashayar, Öberg, Edvin January 2018 (has links)
BorgWarner located in Landskrona are developing components for the four-wheeldrive drivetrain that are being massed produced in the automotive industry. Thanks to Borg- Warner’s unique product’s properties they have achieved a worldwide leading position as a provider of systems for advanced four-wheeldrive drivetrain (all-wheel drivetrain). The assignment from the BorgWarner is to create a better understanding about when vibrations occur and what properties of a friction disc affect vibrations in the wet clutch. The goals of this thesis are to: Map system parameters like Surface topografy. Measure pressure distribution between the friction discs. Measure the Youngs modulus, also known as stiffness. It is not sure that a bad pressure distribution could cause vibrations in the wet clutch. The results from the topography explain the appearance of the pressure distribution. Varying stiffness means that the density of the material is also varying because the stiffness depends on the material composition. When forces are applied on the friction disc, it leads to varying deformation on samples. When the samples all deforms different, the result of the different deformation could be slanting surface. When a disc with non- parallel friction surface rotates it could generate vibration in the wet clutch.
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A variação da profundidade em função do tempo, na saída de um canal retangular curto de declividade nula, após a abertura rápida de uma comporta / The variation of the depth versus time, at the exit of a short rectangular channel of zero slope, after the fast opening of a floodgateElder Damião Barbosa 31 March 2000 (has links)
O escoamento hidrodinâmico é descrito por meio das equações da continuidade e da quantidade de movimento em conjunto com as condições iniciais e de contorno. Neste trabalho de pesquisa, o escoamento não permanente na saída de um canal retangular curto de declividade nula, resultante da abertura rápida de uma comporta foi experimentalmente investigado. Para determinar o coeficiente de pressão e o comprimento do trecho a montante da comporta com distribuição de pressão não hidrostática, usou-se um modelo unidimensional, descrito pelas equações de Saint Venant, para representar o fenômeno. Utilizou-se o método de Lax-Wendroff para obter as curvas características do fenômeno e compará-las com os resultados obtidos experimentalmente. Várias comparações foram feitas possibilitando a avaliação de valores para os parâmetros que definem a região com distribuição de pressão não hidrostática. Os resultados calculados para os valores de parâmetros constantes, estão de acordo com os resultados experimentais. Os resultados experimentais ajustam-se melhor quando os valores dos parâmetros variam no decorrer do tempo. / The hydrodynamic flow is described by means of the equations of the continuity and momentum together with the initial conditions, the boundary conditions. In this research work, the unsteady flow at the exit of a short rectangular channel of zero slope, resulting from the fast opening of a floodgate was investigated experimentally. For determining the pressure coefficient and the length of the upstream reach of the floodgate with non-hydrostatic pressure distribution, a one-dimensional model described by Saint Venant equations is used to represent the phenomenon. The Lax-Wendroff method was used to obtain the curves characteristics of the phenomenon and to compare them with the results obtained experimentally. Several comparisons were made to facilitate the evaluation of values for the parameters that define the region with non-hydrostatic pressure distribution. The results calculated for the values of constant parameters are in agreement with the experimental results. The experimental results are better adjusted when the values of the parameters vary in elapsing of the time.
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The effect of the shoe sole on Plantar Pressure distribution / Påverkan av skosulans utformning på fotens tryckfördelningEjimadu, Geraldine January 2020 (has links)
Patients affected by Diabetes Mellitus have reduced tactile sensitivity and atrophy of the small muscles in the foot, resulting in high-pressure points that may remain unnoticed. The increased pressure can cause micro-trauma leading to wounds. Because of the Diabetes Mellitus, DFUs do not heal easily. Up to 25% of them will develop diabetic foot ulcers (DFU), and 25% of DFUs that do not heal ultimately result in amputation. This Master Thesis will describe and gather results of a newly acquired large international collaborative EU project (EIT Health 2020-2022) between three universities and three companies across Europe. This collaborative group will be the first to tackle the Diabetic Foot Ulcers problem preventatively with an innovative shoe concept, with seven different apex settings, which can be easily modified to avoid ulcerations in different areas of the foot. As an initial pilot, this master thesis project focuses on the analysis of the plantar pressure distribution by using the innovative shoes DR Comfort based on the adjustable rocker profiles, used as a prototype for the prevention of the Diabetic Foot Ulcer (DFU) formation in patients affected by Diabetes. This project captures the motion data of healthy people with different shoe soles while walking at different levels of speed and assess the values of the peak plantar pressure, with the use of the Pedar-X, a measuring system device for the in-shoe plantar pressure. The evaluation of the adjustable rocker profiles is made through the calculation and analysis of the significant differences and p-values in peak plantar pressure, as well as the analysis of the Mean Plantar Pressure (MMP). The results of this study show a reduction (although not pronounced) of the areas that are more affected by DFU. This study cannot be generalized to diabetic patients since ethical approval has not yet been received. / Patienter med DM har minskad taktil känslighet och atrofi i de små musklerna i foten, vilket resulterar i högatryckpunkter som kan för bli obemärkta. Det ökade trycket kan orsaka mikrotrauma som leder till sår. På grund av Diabetes Mellitus, läker inte DFU lätt. Upp till 25% av dem kommer att utveckla diabetiska fotsår (DFU), och 25% av DFU: er som inte läker leder slutligen till amputation. Detta examensarbete kommer att beskriva och samla resultat från ett nyförvärvat stort internationellt EU-projekt (EIT Health 2020-2022) mellan tre universitet och tre företag i hela Europa. Denna samarbetsgrupp kommer att vara den första att förebygga problemet med diabetiska fotsår med ett innovativt skokoncept diabetiska fotsår med ett innovativt skokoncept. De kommer utföras med sju olika inställningar som lätt kan modifieras för att undvika sår på olika områden i foten. Som en första pilot fokuserar detta examensarbete på analys av plantartryckfördelning genom att använda de innovativa DR Comfort-skorna baserade på de justerbara ”rocker”-profilerna, som används som en prototyp för att förebygga bildningen av Diabetic Foot Ulcer (DFU) hos patienter som drabbats av Diabetes. Den här avhandlingen fångar rörelsen hos friska personer med olika skosulor medan de går i olika hastighet och analyserar värdena för det maximala plantartrycket med användning av pedar-x. Pedar-x är en mätanordning för plantorns tryck i skon. Utvärderingen av de justerbara ”rocker”-profilerna gjordes genom beräkning och analys av de signifikanta skillnaderna i top plantartrycket samt analysen av plantartryckets maximala medelvärde (MMP). Resultaten av denna studie visar en minskning (även om den inte betydlig) av de områden som mest drabbats av DFU. Denna studie kan inte generaliseras till diabetespatienter eftersom etiskt godkännande ännu saknas.
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Experimental study of the development flow region on stepped chutesMurillo Munoz, Rafael Eduardo 15 February 2006 (has links)
The development flow region of stepped chutes was studied experimentally. Three configuration of chute bed slopes 3.5H:1V, 5H:1V, and 10H:1V were used to study the flow characteristics. Each model had five horizontal steps and with constant step height of 15 cm. Constant temperature anemometry was used to investigate the velocity field characteristics as well as local void fraction. Pressure transducers were used to examine the pressure distribution. The conditions of aerated and non-aerated cavity were studied.
It was found that the temperature anemometry is a valuable tool in the study of water flow problems due to its good spatial and temporal resolution. It is recommended that the constant overheat ratio procedure should be used in dealing with non-isothermal water flows.
Flow conditions along the development flow region were found to be quite complex with abrupt changes between steps depending whether or not the flow jet has disintegrated. The flow on this region does not resemble a drop structure and after the first step, the step cavity condition does not affect the flow parameters.
Pressure distribution was also found to be complex. It was found that there are no conclusive pressure profiles either on the step treads nor on step risers. No correlation was observed with the values of pool depth.
The instantaneous characteristics of the velocity field along the jet of a drop structure were also studied. It was concluded that the cavity condition does not affect the velocity field of the sliding jet. The shear stress layer at the jet/pool interface was quantified. / May 2006
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Experimental study of the development flow region on stepped chutesMurillo Munoz, Rafael Eduardo 15 February 2006 (has links)
The development flow region of stepped chutes was studied experimentally. Three configuration of chute bed slopes 3.5H:1V, 5H:1V, and 10H:1V were used to study the flow characteristics. Each model had five horizontal steps and with constant step height of 15 cm. Constant temperature anemometry was used to investigate the velocity field characteristics as well as local void fraction. Pressure transducers were used to examine the pressure distribution. The conditions of aerated and non-aerated cavity were studied.
It was found that the temperature anemometry is a valuable tool in the study of water flow problems due to its good spatial and temporal resolution. It is recommended that the constant overheat ratio procedure should be used in dealing with non-isothermal water flows.
Flow conditions along the development flow region were found to be quite complex with abrupt changes between steps depending whether or not the flow jet has disintegrated. The flow on this region does not resemble a drop structure and after the first step, the step cavity condition does not affect the flow parameters.
Pressure distribution was also found to be complex. It was found that there are no conclusive pressure profiles either on the step treads nor on step risers. No correlation was observed with the values of pool depth.
The instantaneous characteristics of the velocity field along the jet of a drop structure were also studied. It was concluded that the cavity condition does not affect the velocity field of the sliding jet. The shear stress layer at the jet/pool interface was quantified.
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