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The Effects of Predation and Supplemental Food on Foraging and Abundance of White-Footed Mice (<i>Peromyscus Leucopus</i>) in Relation to Forest Patch SizeMarcello, Gregory James 05 August 2005 (has links)
No description available.
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A Collaborative Adaptive Wiener Filter for Image Restoration and Multi-frame Super-resolutionMohamed, Khaled Mohamed Ahmied 27 May 2015 (has links)
No description available.
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Wearable and Unobtrusive Electronic Sensor Platform for Biomarker Sensing and Monitoring in SweatRose, Daniel P. January 2016 (has links)
No description available.
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Patch loading resistance of welded I-beams : with respect to misaligned web stiffenersBoutzas, John-Alexander, Zeka, Dafina January 2016 (has links)
When a concentrated load is introduced perpendicular to the flanges of a steel beam, this condition is referred to as Patch loading (Gozzi, 2007). This occurrence is common in many steel structures, for example at supports or during launching of bridges. Because of the usual slenderness of I-beams and other plated structures, these are sometimes reinforced with stiffeners in order to avoid buckling. Modifications, such as adding stiffeners to a beam, are done to make greater plastic deformations possible before buckling can occur; thereby increasing the resistance against failure. Transverse stiffeners are added in areas where the beam is exposed to concentrated loads (Lagerqvist, 1994). The descriptions of calculating patch loading in the Eurocode are presented for cases of double stiffeners, with the load applied in between two stiffeners with same distance to each of them, or when there is one single stiffener that is acting in line with the load. In the Eurocode there are also descriptions on how to calculate on the resistance against patch loading when there are no stiffeners added. However, the Eurocode lacks descriptions for cases when the stiffeners are misaligned. The purpose of this paper is the evaluation of the impact from transverse stiffeners to the resistance of welded I-beams, when the stiffeners are misaligned and where the length of the beam varies. Because of the complexity of such of problems it is almost impossible to find theoretical solutions (Lagerqvist & Johansson, 1996). Therefore, in this study as well as in almost all studies that aim to predict the ultimate resistances of steel beams subjected to patch loading, the results are gained empirically. The tests herein were done by FE-modeling and the results from the physical experiments done in Lagerkvist’s doctoral thesis were used for validation of the model, as conducting experiments ourselves was not economically possible. 6 The study was made in two steps. In the first step FE-models were produced under the same circumstances as the results obtained by Lagerqvist (1994). Those analyses were not part of the aim of the study; the intention for making the initial analyses was to strengthen the reliability of the results. From there, the final analyses were made with the aim in investigating the influence of stiffeners on the resistance, when these are misaligned. In this step, observations were also made with regards to the impact of the bending moment of the beam on its resistance. The initial analyses, which were made for validation of the modeling, had a satisfying correspondence to the physical experiments; hence the final analyses are assumed valid of acceptance. From observations of the results in the final analyses it is noticed that adding stiffeners is a highly preferred way of increasing the resistance for slender beams. For full utilization it is however important to have the stiffeners optimally placed, because a small deviation from this position gives an unwanted decrease in resistance.
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Transfigurations: A Symphonic Work for Orchestra and Live Computer ProcessingVidiksis, Adam January 2013 (has links)
Transfigurations is a symphonic work in one movement for orchestra and live computer processing utilizing the graphical audio programming language Pure Data. The score and patch for this piece are accompanied by an essay describing the audio processing techniques and the compositional processes employed in this work. Programming methods discussed include strategies for data capture, patch structure, user interface, and processor management. All audio processing in the work is realized in realtime. These sounds are derived directly from the orchestra in performance, except for the last. The processes involved in Transfigurations include pitch and amplitude tracking, pitch-shifting, filtering, frequency and amplitude modulation, granular synthesis, delay, and convolution. The final sounds from the computer employ stochastic processes for synthesis which are derived from the germinal materials of the piece. The essay also discusses the aesthetic philosophy and formal structure of the work, principle themes and motives, and formative pitch materials, as well as the compositional processes in each section. The final discourse of the essay considers microphone and loudspeaker setups, patch preparation and leveling, and strategies for rehearsal and performance. / Music Composition / Accompanied by one .pdf file, Transfigurations
for orchestra and live computer processing: Full score, and one .pd file.
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The Preformulation and Formulation Development for Transungual Delivery of Antifungal Drug Ciclopirox olaminePalliyil, Biji January 2013 (has links)
Onychomycosis also known as dermatophytic onychomycosis is the fungal infection of the toenails and fingernails, characterized by discoloration and thickening of the nail and involves the nail plate, nail bed and nail folds. The disease is more than a cosmetic problem, as it severely impacts the patient's quality of life. Onychomycosis is an opportunistic infection in special subpopulations of patients suffering from diabetes, psoriasis, HIV/AIDS etc. The current treatment strategies involve systemic delivery of oral antifungal agents including azoles (e.g. itraconazole) and allylamines (e.g. terbinafine hydrochloride) which are delivered to the nail plate from the nail bed. More recently, topical delivery of drugs including amorolfine and bifonazole/urea (available outside the United States) and Penlac® nail lacquer (ciclopirox) topical solution, 8%, available in the US are an alternative treatment option to the oral antifungal agents. Topical delivery of antifungal agents through the human nail offer several advantages over oral therapy including lower incidence of adverse events and lower potential for drug-drug interaction with drugs used to treat diabetes, HIV/AIDS and psoriasis. The objectives of this project were to: 1) To determine the critical factors affecting the delivery of ciclopirox olamine across the human nail, 2) To screen and select penetration enhancer(s) specific for ciclopirox olamine delivery into the target tissue(s) and 3) To develop a novel transungual formulation containing ciclopirox olamine (CPO) and penetration enhancer(s) for transungual delivery. Ciclopirox olamine, the salt form of the free acid of ciclopirox was used in the study to develop a novel transungual patch formulation and skin and nail permeation from the patch formulation was compared to Penlac® nail lacquer. Various factors such as drug partitioning into the healthy and infected toenail, drug-keratin binding, lateral diffusion, drug-epidermal binding and the formulation components, all play a role in achieving optimum drug penetration and permeation through the nail. Understanding the interplay of these factors helped in the development of an effective topical formulation which was observed to be superior to Penlac® nail lacquer in the in vitro studies. Most cases of onychomycosis show infection and inflammation of the nail folds (skin surrounding the nails). Therefore for an efficient treatment of OM, the antifungal drugs must be delivered to two target tissues - human nail and the nail folds. The major challenges in developing a topical formulation for treatment on OM are: a) Achieving antifungal drug minimum inhibitory concentration (MIC) in the epidermis of the nail folds. b) Enhancing penetration and permeation of the antifungal drug across the human nail to reach the nail bed and achieve the necessary MIC (tissue underneath the nail). Twelve chemical penetration enhancers (PEs) were screened for their ability to enhance ciclopirox olamine accumulation into the nail folds and permeation through the nail. Propylene glycol (PG) enhanced the levels of the drug in the epidermis of the skin while limiting its permeation across the skin. Thiourea (TU) was selected as the best enhancer to increase ciclopirox olamine penetration into the nail. The diffusion of the antifungal drug across the human nail was studied in vitro using human cadaver toenails mounted in Franz diffusion cells. Pressure sensitive adhesives (PSA) belonging to the polyisobutylene, polysiloxane and polyacrylate classes of adhesives were screened to develop a monolithic drug-in-adhesive-type nail patch. The in vitro release of CPO from the PSA patches were limited and did not improve in presence of hydrophilic plasticizer (propylene glycol) and hydrophobic plasticizers (triacetin and triethyl citrate). Increasing the concentration of TU from 1 % to 10 %, lead to its crystallization in the dry patches. Therefore a change in the patch design was recommended. Other hydrophilic polymers including Polyoxyethylene (POLYOX®) and hydroxyl propyl methyl cellulose (HPMC) were also screened to develop a modified drug-in-hydrophilic matrix patch design. The patch was designed to incorporate CPO, PG and TU in the polymer matrix overlaid on a non-occlusive backing membrane cast with polyacrylate PSA. The HPMC films showed the best drug release profile with 80 % release in 2 to 4 hours using a USP apparatus 5. These patches were characterized for drug penetration into the skin and nail permeation. Penlac® nail lacquer was used as the comparator control product. The prototype HPMC K15M patch containing 10 %w/w each of the drug and TU and 150 % w/w of PG showed 2.8 fold increase in CPO accumulation in epidermis compared to Penlac® nail lacquer in 24 hours. The skin permeation was found to be similar to that of Penlac®. The HPMC K15M patch formulation showed 2.7 fold increase in CPO concentration within the nail and 4.2 fold increase in transungual flux compared to Penlac®. The patch delivered higher levels of ciclopirox olamine into the target tissues with a lower permeation lag-time. The novel nail patch delivery system had the following properties: a) Ease of application, b) Contact with the nail surface, c) Increased concentration of drug in dissolved form within the patch, d) Presence of enhancers. The novel nail patch formulation has shown increased efficiency in topical and transungual drug delivery for treatment of OM, when compared to the commercial formulation, Penlac® nail lacquer in the in vitro studies. The physical characterization of the patch using Scanning Electron Microscopy, Polarized Light Microscopy, Optical Light Microscopy, Differential Scanning Calorimetry, X-Ray Diffractometer and Fourier Transform Infrared Spectroscopy show that ciclopirox olamine exists at a sub-saturation level in a non-crystalline form in the patch without any significant drug-polymer interaction. In conclusion, all the objectives of the study were met by successfully selecting penetration enhancers for CPO delivery into the nail folds and across the nail plate, evaluating the interaction between CPO and target tissues, developing a transungual patch system and characterizing the novel transungual patch. / Pharmaceutical Sciences
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Electrophysiology of interstitial cells of CajalWright, George January 2017 (has links)
This thesis focuses on elucidating the electrical mechanisms underlying excitation of small intestinal and colonic smooth muscle initiated by interstitial cells of Cajal (ICC). All the ICC subtypes are involved in the orchestration, generation, and/or transmission of electrical signals to smooth muscle to pace gut motor patterns. Some ICC types have intrinsic activity leading to omnipresent rhythmic changes in smooth muscle excitability; others respond to stimuli, inducing pacemaker activity as required. Together they orchestrate motor patterns such as propulsion and segmentation, essential functions of the gut. To study ICC electrophysiology, I utilized patch clamping to record ion channel currents from single intestinal ICC and sharp microelectrodes to record colonic smooth muscle membrane potentials. I have made several discoveries contributing to our understanding of ICC electrophysiology. Firstly, my research increased our understanding of the properties of intrinsic pace-maker activity. I showed that maxi Cl– channels from small intestinal ICC make a significant contribution to slow wave depolarization triggered by intracellular calcium. Secondly, I showed that colonic intramuscular ICC (ICC-IM) selectively express KV7.5 channels, which are suppressed by cholinergic agonists, meaning that excitatory stimuli triggering acetylcholine release deactivate KV7.5 channels, leading to increased excitability. Thirdly, I have shown that the bile acid chenodeoxycholic acid and the nitric oxide donor sodium ni-troprusside both induce pacemaker activity, rhythmic transient depolarisations in mouse colonic muscle, which led to the hypothesis that nitrergic nerves are involved in generating inducible myenteric plexus ICC (ICC-MP) pacemaker activity. It is only when ICC are suitably stimulated by intracellular processes such as rhythmic Ca2+ transients or extracellular signalling from neurotransmitters or small molecules, that ICC produce membrane potential rhythmicity, required for generation of intrinsic slow waves, low-frequency rhythmic transient depolarisations and transmission of excitation into the muscle. / Thesis / Doctor of Philosophy (PhD) / The gut is essential for digestion and absorption of food. The gut has special cells called interstitial cells of Cajal (ICC), which control the contractions of the gut muscle. ICC are pacemaker cells, like those that pace heart beats. To pace gut muscle contractions, ICC generate electrical signals which cause the muscle to contract in an organized rhythmic manner, which promotes mixing or propulsion of gut contents, called motility. I used tiny electrodes to record electrical activity from ICC or gut muscle, to improve our understanding of how ICC pacemaker activity controls motility. My research characterised ion channels, which are microscopic protein pores that allow cells to make electrical currents, that enable generation of pacemaker signals by ICC. I also investigated activation of ICC electrical activity that causes propulsive colonic motility. This will hopefully lead to treatment improvements for patients with motility disorders in the future.
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Receptores cys-loop : mecanismos moleculares de activación y modulación por fármacos neuroactivosAndersen, Natalia 06 March 2014 (has links)
Los receptores cys-loop pertenecen a la familia de canales iónicos pentaméricos activados por ligandos (pLGICs). Se expresan ampliamente en el sistema nervioso, donde ejercen un rol vital en la comunicación neuronal. Están involucrados en los procesos de aprendizaje, memoria, movimiento, entre otros. Se han asociado alteraciones en la funcionalidad de estos receptores con una gran variedad de desórdenes neurológicos, tales como enfermedad de Alzheimer, enfermedad de Parkinson, epilepsia, síndromes miasténicos, esquizofrenia y depresión. Por ello, los receptores cys-loop son importantes blancos farmacológicos. En consecuencia, consideramos que el conocimiento de los mecanismos moleculares que conducen a su activación y disfunción es de suma relevancia. Los receptores Cys-loop están formados por un dominio extracelular, que contiene los sitios de unión de agonista, y un dominio transmembrana, que forma el poro iónico. La interfase entre ambos dominios, llamada región de acoplamiento, desempeña un rol clave en la propagación de los cambios conformacionales que se inician con la unión del agonista en la región extracelular y culminan con la apertura del poro iónico a nivel transmembranal. En este trabajo de Tesis Doctoral estudiamos dos regiones claves en el proceso de activación de los receptores Cys-loop: el sitio de unión de agonista, donde comienza la respuesta, y la interfase entre los dominios extracelular y transmembrana o región de acoplamiento. Utilizamos receptores homopentaméricos que por estar compuestos por cinco subunidades iguales, poseen cinco sitios de unión de agonista y cinco regiones de acoplamiento idénticas. Los receptores homoméricos surgieron más tempranamente en la escala evolutiva por lo que presentan características estructurales y funcionales comunes a todos los miembros Cys-loop, y son, por lo tanto, modelos útiles para el estudio de los receptores de esta familia. En el Capítulo I de esta Tesis determinamos el número de regiones de acoplamiento necesario para la activación de los receptores Cys-loop y su relación con los sitios de unión de agonista. Para ello, utilizamos como modelo de receptor homopentamérico al receptor quimérico a7-5HT3A, compuesto por secuencias del receptor a7 en su dominio extracelular y secuencias del receptor 5-HT3A en su dominio transmembrana, el que ha sido ampliamente utilizado como modelo de a7.
Para conocer la contribución de cada una de las cinco regiones de acoplamiento a la estabilidad de canal abierto del receptor a7-5HT3A, empleamos nuestra estrategia experimental denominada electrical fingerprinting. Según esta estrategia, co-transfectamos células con una subunidad conteniendo la región de acoplamiento activa y otra subunidad conteniendo la región de acoplamiento inactiva, una de ellas conteniendo además mutaciones reporteras de conductancia. De esta forma, logramos expresar en membrana receptores con distinto número de regiones de acoplamiento funcionales que son identificados mediante registros de patch-clamp de canal único. Gracias a la presencia de las mutaciones reporteras de conductancia, la medición de la amplitud de cada apertura nos permitió conocer la estequiometria del receptor, es decir, el número de subunidades con región de acoplamiento funcional que tiene el receptor pentamérico que dio origen a esa apertura. Determinamos la duración de los eventos de apertura provenientes de receptores con distinto número de regiones de acoplamiento funcionales, que constituye una medida de la estabilidad de canal abierto. Encontramos que cada región de acoplamiento contribuye en forma independiente y simétrica a la estabilidad del canal abierto y que son necesarias las cinco regiones de acoplamiento funcionales para lograr la óptima activación del receptor. Demostramos además que la presencia de una sola región de acoplamiento funcional en el pentámero es suficiente para lograr la activación pero no permite mantener el canal abierto en su tiempo óptimo. Además generamos receptores a7-5HT3A mutantes, que contenían distinto número de sitios de unión de agonista y regiones de acoplamiento funcionales. Esta estrategia nos permitió establecer los requisitos estructurales mínimos que logran la activación del receptor, así como también los requerimientos estructurales que conducen a la máxima estabilidad del estado abierto. Encontramos que el receptor es capaz de responder al agonista mediante la ocupación de un único sitio si este se encuentra formado por dos subunidades con regiones de acoplamiento funcionales. Sin embargo, para lograr la óptima activación y duración máxima del canal abierto, el receptor modelo utilizado requiere de tres sitios de unión de agonista funcionales y sus cinco regiones de acoplamiento intactas. En el Capítulo II, estudiamos la activación del receptor neuronal a7 en condiciones de sub-ocupación de sus cinco sitios de unión de agonista. Este receptor se localiza principalmente en sitios distantes a los sitios de síntesis y liberación de acetilcolina (ACh), por lo que la ACh, o su producto colina, deben difundir y unirse a receptores a7 distantes. Este mecanismo colinérgico no sináptico predice que el grado de ocupación de los receptores a7 sería bajo en condiciones fisiológicas.
Para estudiar la activación del receptor a7 en condiciones de sub-ocupación de sus sitios de agonista, realizamos ensayos electrofisiológicos y medimos la duración del canal abierto de receptores individuales que presentan un único sitio de unión de agonista funcional, y la comparamos con la de receptores que tienen sus cinco sitios funcionales. Para conocer el número de sitios de unión de agonista funcionales empleamos nuevamente la estrategia electrical fingerprinting. Esta estrategia requiere la medición exacta de la amplitud. Teniendo en cuenta que los receptores a7 presentan aperturas de duración breve que no permiten la resolución de su máxima amplitud, los estudios electrofisiológicos se realizaron sobre receptores a7 mutados o en presencia de potenciadores que aumentan la duración del canal abierto. En este trabajo, demostramos que la estabilidad del canal abierto de receptores a7 que presentan un único sitio de unión de agonista funcional es la misma que la de los receptores que presentan sus cinco sitios disponibles. Por otro lado, cuando reemplazamos el dominio transmembrana del receptor a7 por el del receptor 5-HT3A, encontramos que la duración del canal abierto se incrementa al aumentar el número de sitios ocupados por agonista. Este resultado demuestra por primera vez que el dominio extracelular no es el único determinante de la relación entre ocupación y estabilidad del canal abierto. Por lo tanto, en este trabajo demostramos la capacidad del receptor a7 de activarse y producir respuestas máximas con la ocupación de un solo sitio de unión de agonista, propiedad que es única y exclusiva de este receptor dentro de todos los miembros de la familia de receptores Cys-loop. Este resultado posee además relevancia fisiológica dado que esta propiedad le permitiría al receptor adaptarse al mecanismo de transmisión no sináptico. En su conjunto, los resultados que surgen de esta Tesis revelan una novedosa relación funcional entre dos dominios estructurales de estos receptores, el sitio de unión de agonista y la región de acoplamiento, y, además, contribuyen al conocimiento general del mecanismo de activación de los receptores de la familia Cys-loop. / Cys-loop receptors belong to the family of pentameric ligand-gated ion channels (pLGICs). They are widely expressed in the nervous system, where they exert a vital role in neuronal communication. They are involved in learning, memory, movement processes, among others. Functional disorders of these receptors have been associated with several neurological disorders, such as Alzheimer's disease, Parkinson's disease, epilepsy, myasthenic syndromes, schizophrenia and depression. Because Cys-loop receptors are important pharmacological targets for the development of therapies, the knowledge of the molecular mechanisms leading to activation and dysfunction of these receptors is of great importance. Cys-loop receptors contain an extracellular domain that carries the agonist binding sites and a transmembrane region that forms the ion pore. The interface between both domains, named as the coupling region, plays a key role in the propagation of the conformational changes from the binding site at the extracellular domain to the pore, located at the transmembrane region. In this Thesis, we studied two key regions that are essential for the activation process of Cys-loop receptors: the agonist binding site, where the response begins, and the interface between the extracellular and transmembrane domains or coupling region. We used homopentameric receptors that contain five identical subunits, and therefore five identical agonist binding sites and coupling regions. Because homomeric receptors appeared earlier on the evolutionary scale, they present structural and functional features that are common to all Cys-loop members, and are therefore useful models for the study of this receptor family. In Chapter I of this Thesis we studied the number of coupling regions necessary for Cys-loop receptor activation and evaluated the functional relationship of this domain with the agonist binding sites. To this end, we used a model of homopentameric receptor, the a7-5HT3A chimeric receptor, which contains a7 sequences in the extracellular domain and 5-HT3A sequences in the transmembrane domain.
To determine the contribution of each of the five coupling regions to the stability of the open channel, we used our experimental strategy which is called electrical fingerprinting. For this strategy, cells were co-transfected with a subunit with an active coupling region and another subunit with an inactive coupling region, one of which carrying reporter conductance mutations, to generate receptors with different number of functional coupling regions. Next, we performed single-channel recordings to identify functional receptors using the patch-clamp technique. Due to the introduction of reporter conductance mutations, the measurement of the amplitude of each opening event allowed us to know receptor stoichiometry, i.e., the number of subunits with functional coupling region present in the pentameric receptor which originated the event. We measured open channel duration of receptors with different numbers of functional coupling regions, which indicates the open channel stability. We found that each coupling region contributes independently and symmetrically to open channel stability. We showed that five coupling regions are necessary to achieve optimal receptor activation and that the presence of only one functional coupling region is sufficient for receptor activation, but with reduced open channel duration. Furthermore, we constructed a7-5HT3A mutant receptors, containing different number of agonist binding sites and functional coupling regions. This strategy allowed us to establish the minimum structural requirements for receptor activation as well as the structural requirements for maximal open channel stability. We found that a7-5HT3A receptors are capable of responding to agonist by occupying a single agonist binding site, only if this site is formed by two subunits carrying functional coupling regions. However, to achieve optimal activation and maximal open channel duration, the model receptor requires three functional agonist binding sites and five functional coupling regions. In Chapter II, we studied a7 neuronal receptor activation under sub-occupancy conditions of its five agonist binding sites. In the brain, this receptor is mainly located at distant sites from the sites of synthesis and release of acetylcholine (ACh), so ACh, or its product choline, diffuse to bind distant a7 receptors. This non-synaptic cholinergic mechanism predicts that the degree of a7 receptor occupancy is low under physiological conditions. To study a7 activation under sub-occupancy conditions we performed single-channel recordings and measured open channel duration of receptors with only one functional agonist binding site, and compared it with that of receptors containing their five intact agonist binding sites. To know the number of agonist binding sites, we employed again the electrical fingerprinting strategy. This strategy requires accurate measurement of open channel amplitude. Because the brief duration of a7 opening events do not allow full amplitude resolution, single-channel recordings were performed in either a7 mutant receptors or in the presence of potentiators that increase open channel duration. In this work, we demonstrated that open channel stability of receptors with a single agonist binding site is the same as that of receptors containing five functional sites.
Moreover, when we replaced the transmembrane domain of a7 receptors by that of 5-HT3A receptor, we found that open channel lifetime increases as the number of sites
occupied by agonist increases. This result shows for the first time that the extracellular domain is not the only determinant of the relationship between occupancy and open channel stability. Therefore, in this work we demonstrated the ability of a7 receptor for activation and eliciting maximal responses with occupancy of only one agonist binding site, a property that is unique for a7 among all members of the Cys-loop family. This result has a physiological relevance since this property would allow a7 receptors to adapt to their non-synaptic mechanism. Taken together, the results that emerge from this Thesis reveal a novel functional relationship between two structural domains, the agonist binding site and the coupling region, and contribute to the general knowledge of the activation mechanism of Cys-loop receptors.
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Stochastic Simulation of the Suspended Sediment Deposition in the Channel With Vegetation and Its Relevance to Turbulent Kinetic EnergyYang, L., Huai, W., Guo, Yakun 22 March 2022 (has links)
Yes / The aquatic vegetation patch plays a significant role on sediment net deposition in the vegetated channels. Particularly, the flow is decelerated at the leading edge of a patch that tends to induce vertical updraft, that is, a diverging flow region, in which vegetation greatly affects the pattern of sediment net deposition. This study focuses on the simulation of the sediment net deposition in the whole vegetation patch region through an innovative random displacement model, a Lagrange method, with probability-based boundary conditions, instead of the reflection or sorption boundary at the channel bottom. The probability model of deposition and resuspension is proposed according to the flow field characteristics in the different regions of the vegetation patch. The variation of the sediment deposition and resuspension with the turbulent kinetic energy is analyzed to illustrate the effect of the turbulence induced by vegetation, represented by the dimensionless turbulent kinetic energy (ψ), on the sediment deposition and resuspension. The sediment deposition predicted by the proposed model agrees well with the experimental measurements. Results show that the effect of vegetation on the sediment deposition and resuspension motions begins to prevail when the vegetation-induced ψ is larger than its threshold, ψ *. The threshold of ψ is predicted to be within 6.8–10 according to the simulation results in this study. As the turbulent kinetic energy increases, the deposition probability decreases continuously when ψ > ψ *. / ational Natural Science Foundation of China (NSFC). Grant Numbers: 52020105006, 11872285; UK Royal Society - International Exchanges Program. Grant Number: IES\R2\181122; Open Funding of State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University. Grant Number: 2018HLG01
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Strength and Life Prediction of FRP Composite Bridge DeckMajumdar, Prasun Kanti 30 April 2008 (has links)
Fiber reinforced polymer (FRP) composites are considered very promising for infrastructure applications such as repair, rehabilitation and replacement of deteriorated bridge decks. However, there is lack of proper understanding of the structural behavior of FRP decks. For example, due to the localization of load under a truck tire, the conventionally used uniform patch loading is not suitable for performance evaluation of FRP composite deck systems with cellular geometry and relatively low modulus (compared to concrete decks). In this current study, a simulated tire patch loading profile has been proposed for testing and analysis of FRP deck. The tire patch produced significantly different failure mode (local transverse failure under the tire patch) compared to the punching-shear mode obtained using the conventional rectangular steel plate. The local response of a cellular FRP composite deck has been analyzed using finite element simulation and results are compared with full scale laboratory experiment of bridge deck and structure. Parametric studies show that design criteria based on global deck displacement is inadequate for cellular FRP deck and local deformation behavior must be considered.
The adhesive bonding method is implemented for joining of bridge deck panels and response of structural joint analyzed experimentally. Strength, failure mode and fatigue life prediction methodologies for a cellular FRP bridge deck are presented in this dissertation. / Ph. D.
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