Дисертації з теми "Transit and Residence Times"
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Grebenkov, Denis S. "Residence times of reflected brownian motion." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193387.
Повний текст джерелаGrebenkov, Denis S. "Residence times of reflected brownian motion." Diffusion fundamentals 6 (2007) 21, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14195.
Повний текст джерелаMcTait, Graeme Edgar. "Residence times and solid flows in rotary kilns." Thesis, University of Cambridge, 1999. https://www.repository.cam.ac.uk/handle/1810/251697.
Повний текст джерелаMüller, Thomas. "Recharge and residence times in an arid area aquifer." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-119348.
Повний текст джерелаEin steigender Bedarf nach landwirtschaftlichen Produkten - und damit Wasser - bei gleichzeitiger Abnahme des verfügbaren Wassers in Qualität und Menge in den bisherigen Anbaugebieten, führt zu einer intensiven Nutzung der Grundwasserressourcen der ariden Najd-Region in der Provinz Dhofar, im Süden des Sultanats Oman. Als Quelle dienen die Grundwasservorräte des Umm Er Radhuma-Aquifers, einer der Hauptaquifere auf der arabischen Halbinsel. Der steigenden Nutzung stehen mit dem jährlichen Monsoon, der regional limitiert ist, und unrgelmässigen, zwischen 3 und 7 Jahren auftretenden Unwettern (Zyklonniederschlag) nur begrenzte Niederschlagsmengen als Quellen für eine mögliche Zufuhr von Wasser (Grundwasserneubildung) zum Aquifersystem gegenüber. Der Ansatz der vorliegenden Arbeit besteht darin, mit Hilfe eines Grundwassermodells und der Einbeziehung von Umweltisotopen das tiefe und zur Nutzung geförderte Grundwasser in der Najd-Region als Teil eines aktiven Fließsystemes zu untersuchen und mittlere Verweilzeiten des Grundwassers abzuleiten. Ein 2D-Grundwassermodell entlang einer Fließlinie vom Dhofar Gebirge im Süden zur Sabkha Umm as Sammim im Nordosten wurde entwickelt. Das Modell reproduziert den Süd-Nord-Gradienten als auch den aufwärts gerichteten Gradienten mit höheren Grundwasserständen in den tiefen Grundwasserleitern. Die Simulationen zeigen, dass der Wechsel von ariden und humiden Phasen (wenig bzw. viel Grundwasserneubildung) zu Veränderungen der Grundwasseroberfläche führt die mehrere tausend Jahre anhalten können. Das kalibrierte Grundwassermodel zeigt, dass mit einer Neubildungsrate von 4 mm a−1 die natürlichen Grundwasserverhältnisse im Najd abgebildet werden können. Dass eine moderne Grundwasserneubildung stattfindet, konnte mittels Loggermessungen anhand steigender Grundwasserstände im tiefen Aquifersystem nach dem Extremunwetter im November 2011 (Zyklon Keila) eindeutig nachgewiesen werden. Die Analyse der 36Cl- und 4He-Konzentrationen zeigt, dass die tiefen Grundwasser im zentralen Najdgebiet bis 550 000 Jahren alt sein können. Das bedeutet allerdings, dass die über 14C Daten berechneten Grundwasseralter mit ca. 20 000 Jahren für das zentrale Najdgebiet und bis zu 35 000 Jahren für den nördlichen Najd, die Grundwasseralter deutlich unterschätzen. Die abnehmenden 36Cl und ansteigenden 4He Konzentrationen zeigen den erwarteten Trend in Grundwasserfließrichtung und können als aussagefähige Tracer für die Bewertung der Verweilzeiten und Alter des fossilen Grundwassers der Najd-Region angesehen werden. Mit Hilfe des Partickeltrackings wurden die Grundwasseralter, basierend auf den Isotopentracern, im Grundwassermodel simuliert. Die Porosität wurde dabei für das Aquifesystem mit Werten zwischen 15 und 20 % bestimmt. Die generierten Parameter und das gewonnene Systemverständnis sind eine wichtige Basis für zukünftige 3D-Modellstudien welche die Verfügbarkeit der Wasserresourcen im Najd untersuchen werden. Weitere Anwendungen für das in dieser Studie aufgebaute 2D-Modell sind Untersuchungen zum Paläoklima und dessen Einfluss auf das Grundwassersystem
Sheikh, M. S. "Prediction of particle residence times in cascading rotary dryers." Thesis, Teesside University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378933.
Повний текст джерелаLangkau, Katharina. "Flows over time with flow dependent transit times." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968912656.
Повний текст джерелаStolp, Bernard Jan. "Determining mean transit times of groundwater flow systems." Thesis, The University of Utah, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3614458.
Повний текст джерелаWater is the elementary component of life on Earth, and quantifying this resource is critical to understanding ecosystem viability on planetary, continental, and local scales. In a simplified partition of the Earthfs freshwater resources, 75% is ice at the north and south poles, 25% is groundwater, and 0.01% exists in lakes and streams. Mean transit time is a robust description of groundwater volume within the discrete aquifers that together make up the 25% of Earthfs freshwater. Mean transit time can be estimated using environmental tracer concentrations in springs and gaining streams. That is because springs and streams are locations where groundwater flow paths naturally converge. Converging flowpaths create discharge that is a flow]weighted mixture of water from the contributing aquifer. The age of that flow-weighted mixture is a good measure of the mean transit time of water as it discharges from the contributing aquifer. Mean transit time can be directly used to estimate the volume of groundwater storage in the aquifer.
Although simple in principle, there are several important topics that need to be considered when collecting and dating a broad mixture of flow paths. They include 1) the necessity for a basic conceptual perception of the investigated aquifer, 2) the non-conservative aspect of most age-dating environmental tracers once exposed to the atmosphere, and 3) the importance of estimating a transit-time distribution. These specific topics are discussed in this dissertation.
Cevallos, Fabian. "Optimization of transit transfer times : a system-wide approach." FIU Digital Commons, 2006. http://digitalcommons.fiu.edu/etd/2099.
Повний текст джерелаOliveira, Anabela Pacheco de. "Eulerian-Lagrangian analysis of transport and residence times in estuaries and coasts /." Full text open access at:, 1997. http://content.ohsu.edu/u?/etd,209.
Повний текст джерелаHodal, Michal. "Net physical transports, residence times, and new production for Rivers Inlet, British Columbia." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/30635.
Повний текст джерелаBuchbender, Florian [Verfasser]. "Single-drop-based modelling of drop residence times in Kühni columns / Florian Buchbender." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1038571855/34.
Повний текст джерелаHess, Jacquelyn Marie. "Distribution and residence times of large woody debris along South River, Shenandoah Valley, Virginia." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 184 p, 2007. http://proquest.umi.com/pqdweb?did=1400957071&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Повний текст джерелаTruong, Gold. "Forecasting linehaul transit times & on time delivery probability using quantile regression forests." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90751.
Повний текст джерелаThesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 85).
with delays on the road and variabilities introduced by the major participants in the process, ie: distribution centers, drivers, etc. These sources of variability also make it difficult to measure the impact changes in transit time have on on-time performance. This paper focuses on trying to identify indicators of variability and incorporates them into quantile regression forest, a black box forecasting model, that will provide estimated scheduled transit times for a given probability of on-time arrival at the destination. With the use of Amazon's Q1 & Q2 2013 linehaul data, an analysis on performance trends based on length of haul were categorized to develop an understanding linehauls in North America. The outbound transportation team at Amazon faces the complex trade off between providing a sufficient amount of scheduled transit time to ensure ontime delivery to destination and the utilization rate of a truck. The ability to quantify how changes in scheduled transit time impact the performance of a particular linehaul allows transportation managers to assess this trade off. The paper explores a machine learning regression technique called quantile regression forests. The model was developed in R using the quantregforest package. It incorporates numerous factors about linehaul including: origin, destination, historical reporting on sources of late to arrivals, time to depart from origin and time of departure. The strengths of this black box model are in its ability to handle a large amount of data and continuously update its predicting structure to provide more accurate recommendations. Quantile regression forests also enable the user to specify the ontime performance percentage, p, that he/she wants the model to predict based on historical data. The final model at p = 95% provided a weight mean absolute percent error of 4.57% and a root mean square error of 2.22%. A four-week pilot was conducted to validate these predictions and the results are discussed.
by Gold Truong.
M.B.A.
S.M.
Séguin, Marc-André. "Fuel Residence Times for Clean Combustion of Coal in a Pressurized Fluidized Bed - Cold Flow Study." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36244.
Повний текст джерелаJanos, Débora. "Regional groundwater flow dynamics and residence times in Chaudière-Appalaches, Québec, Canada : insights from numerical simulations." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27813.
Повний текст джерелаDans le cadre du projet PACES III pour la région de Chaudière-Appalaches, situé au sud de la ville de Québec, au Canada, l'étude présente une analyse approfondie de l’influence des dynamiques d’écoulement sur la qualité des eaux souterraines dans un contexte régional. L’écoulement régional, le transport d’âge et l'impact d'une faille sur la qualité de l'eau souterraine sont étudiés par l’entremise de modèles numériques bidimensionels. La combinaison des connaissances hydrogéologiques physiques et chimiques, y compris une analyse des concentrations de ¹⁴C dans les eaux souterraines échantillonnées, a conduit à l’ébauche d'un modèle conceptuel de l’écoulement régional. Ce dernier est mis à l’essais pas l’entremise d’un modèle d'écoulement numérique suivant une ligne d’écoulement régionale dans le plan 2D vertical à l’aide du logiciel FLONET. Le modèle est d'abord calibré à l’aide d’une méthode semi-automatisé qui utilise le logiciel PEST en comparant les charges simulés à la piézométrie régionale, et est validé par la comparaison des flux simulés à la recharge. Bien que le modèle affiche l’existence d’un écoulement régional profond, la région à l’étude apparaît être dominée par des systèmes d'écoulements locaux à des échelles maximales d'environ 5 km, avec un écoulement significatif dans le roc fracturé peu profond. L’écoulement actif se limitant à une profondeur maximale de 40 m à 60 m du roc fracturé, confirme que la géochimie des eaux souterraines échantillonnées à partir de puits résidentiels est susceptible d'être affectée par les eaux faisant parti de l’écoulement intermédiaire et régional. Le transport advectif-dispersif de l'âge est ensuite simulé avec le simulateur de transport TR2 et comparé aux temps de déplacement advectifs le long des lignes d’écoulements et à l'âge ¹⁴C des eaux échantillonnées. Enfin, l’influence de la faille de la Rivière Jacques Cartier sur le contexte hydrogéologique régional est étudiée à travers divers scénarios hypothétiques de perméabilité de faille.
As part of the PACES III project in the Chaudière-Appalaches region, south of Quebec City, Quebec, Canada, the study herein presents insights into the extent to which regional groundwater quality is shaped by flow dynamics. In this context, 2D numerical modelling is used to simulate regional flow, transport of groundwater age and the possible influence of a fault on groundwater quality. Combining physical and chemical hydrogeological knowledge, including an analysis of ¹⁴C concentrations in sampled groundwater, leads to the development of a regional conceptual flow model. The conceptual model is tested by representing the system with a two-dimensional numerical flow model oriented in the vertical plane roughly south-north towards the St. Lawrence River using the FLONET code. The model is first calibrated to regional piezometry through a semi-automated workflow using PEST and is then validated with average recharge values. Although some evidence for deeper regional flow exists, the area appears to be dominated by local flow systems on maximum length scales of about 5 km, with significant flow through the shallow fractured sedimentary rock aquifer. This regional scale flow model is also supported by the local hydrogeochemical signatures. Active flow appears contained within the top 40 m to 60 m of the fractured bedrock, which confirms that the geochemical signatures of groundwater sampled from residential wells are likely affected by the slow moving waters of the intermediate and regional flow systems. Advective-dispersive transport of groundwater age is then simulated with the TR2 transport model and compared with advective travel times and sampled ¹⁴C water ages. Finally, the possible role of the Jacques-Cartier River fault on regional flow dynamics is investigated by testing various fault permeability configurations.
Starr, David E. "Microcalorimetric heats of adsorption, surface residence times and sticking probabilities of metals on metal-oxide, and silicon substrates /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/8492.
Повний текст джерелаMüller, Thomas [Verfasser], Rudolf [Akademischer Betreuer] Liedl, Werner [Akademischer Betreuer] Aeschbach-Hertig, and Johannes [Akademischer Betreuer] Barth. "Recharge and residence times in an arid area aquifer / Thomas Müller. Gutachter: Rudolf Liedl ; Werner Aeschbach-Hertig ; Johannes Barth." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068153415/34.
Повний текст джерелаYeung, Au Lai-Kit Rikkie. "The governance of government-owned railway organisations in Hong Kong integration and autonomy in changing times /." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31057925.
Повний текст джерелаBroxton, Patrick. "UNDERSTANDING THE IMPORTANCE OF ASPECT ON MOUNTAIN CATCHMENT HYDROLOGY: A CASE STUDY IN THE VALLES CALDERA, NM." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193452.
Повний текст джерелаGoodwin, Angela Jasna. "Oxygen-18 in surface and soil waters in a dryland agricultural setting, Eastern Washington : flow processes and mean residence times at various watershed scales." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Spring2006/A%5FGoodwin%5F042506.pdf.
Повний текст джерелаEranki, Anitha. "A model to create bus timetables to attain maximum synchronization considering waiting times at transfer stops." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000225.
Повний текст джерелаWang, Yuxuan. "A Methodology for Identifying Inconsistencies Between Scheduled and Observed Travel and Transfer Times using Transit AVL data: Framework and Case Study of Columbus, OH." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593636407701171.
Повний текст джерелаMerget, Benjamin [Verfasser], and Christoph [Gutachter] Sotriffer. "Computational methods for assessing drug-target residence times in bacterial enoyl-ACP reductases and predicting small-molecule permeability for the \(Mycobacterium\) \(tuberculosis\) cell wall / Benjamin Merget ; Gutachter: Christoph Sotriffer." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1125884541/34.
Повний текст джерелаFabbro, Gareth Nicholas. "The timescales of magmatic processes prior to a caldera-forming eruption." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22452/document.
Повний текст джерелаLarge, explosive, caldera-forming eruptions are amongst the most destructive phenomena on the planet, but the processes that allow the large bodies of crystal-poor silicic magma that feed them to assemble in the shallow crust are still poorly understood. Of particular interest is the timescales over which these reservoirs exist prior to eruption. Long storage times—up to 105 y—have previously been estimated using the repose times between eruptions and radiometric dating of crystals found within the eruptive products. However, more recent work modelling diffusion within single crystals has been used to argue that the reservoirs that feed even the largest eruptions are assembled over much shorter periods—101–102 y. In order to address this question, I studied the >10km3, 22-ka, dacitic Cape Riva eruption of Santorini, Greece. Over the 18 ky preceding the Cape Riva eruption a series of dacitic lava dome and coulées were erupted, and these lavas are interspersed with occasional dacitic pumice fall deposits (the Therasia dome complex). These dacites have similar major element contents to the dacite that was erupted during the Cape Riva eruption, and have previously been described as “precursory leaks” from the growing Cape Riva magma reservoir. However, the Cape Riva magma is depleted in incompatible elements (such as K, Zr, La, Ce) relative to the Therasia magma, as are the plagioclase crystals in the respective magmas. This difference cannot be explained using shallow processes such as fractional crystallisation or crustal assimilation, which suggests that the Cape Riva and Therasia magmas are separate batches. Furthermore, there is evidence that the Therasia dacites were not fed from a long-lived, melt-dominated reservoir. There are non-systematic variations in melt composition, plagioclase rim compositions, and plagioclase textures throughout the sequence. In addition, high-temperature residence times of plagioclase and orthopyroxene crystals from the Therasia dacites estimated using diffusion chronometry are 101–102 y. This is short compared to the average time between eruptions (1,500 y), which suggests the crystals in each lava grew only shortly before eruption. The different incompatible element contents of the Cape Riva and Therasia magmas and plagioclase crystals suggest that a new batch of incompatible-depleted silicic magma arrived in the shallow volcanic plumbing system shortly before the Cape Riva eruption. This influx must have taken place after the last Therasia eruption, which 40Ar/39Ar dates show occurred less than 2,800±1,400 years before the Cape Riva eruption. The rims of the plagioclase crystals found in the Cape Riva dacite are in equilibrium with a rhyodacite, with a similar composition to the Cape Riva glass. However, the major and trace element zoning patterns of the crystals record variations in the melt composition during their growth. The compositions at the centre of most crystals are the same as the rims; however, these crystals are often partially resorbed and overgrown by more calcic plagioclase. The plagioclase then grades normally back to rim compositions. This cycle is repeated up to three times. The tight relationships between the anorthite, Sr and Ti contents of the different zones suggests that the composition of the plagioclase crystals correlates with the composition of the melt from which theygrew. The different plagioclase compositions correspond to dacitic and rhyodacitic melt compositions. The orthopyroxene crystals reveal a similar sequence, although they only record one cycle. These zoning patterns are interpreted to document the assembly of the Cape Riva reservoir in the shallow crust through the amalgamation of multiple batches of compositionally diverse magma. Models of magnesium diffusion in plagioclase and Fe–Mg interdiffusion in orthopyroxene suggest that this amalgamation took place within 101–102 y of the Cape Riva eruption
Alling, Vanja. "Terrestrial organic carbon dynamics in Arctic coastal areas : budgets and multiple stable isotope approaches." Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43455.
Повний текст джерелаAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In press. Paper 2: Submitted. Paper 4: Manuscript.
Ramirez-garcia, Eloy. "Analyse expérimentale et modélisation du bruit haute fréquence des transistors bipolaires à hétérojonctions SiGe et InGaAs/InP pour les applications très hautes fréquences." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112082/document.
Повний текст джерелаIn order to fulfil the roadmap for the development of telecommunication and information technologies (TIC), low noise level and very fast semiconductor devices are required. Heterojunction bipolar transistor has demonstrated excellent high frequency performances and becomes a candidate to address TIC roadmap. This work deals with experimental analysis and high frequency noise modelling of Si/SiGe:C HBT (STMicroelectronics tech.) and InP/InGaAs HBT (III-V Lab Alcatel-Thales).Chapter I introduces the basic concepts of HBTs operation and the characterization at high-frequency. This chapter summarizes the high frequency performances of many state-of-the-art HBT technologies. The first part of chapter II describes the two HBT sets, with paying attention on the impact of the base composition (SiGe:C) or the lateral reduction of the device (InGaAs) on static and dynamic performances. Based on TCAD modelling, the second part shows that a 15-25% germanium composition profile in the base is able to reach highest dynamic performances. Chapter III summarizes the static and dynamic results at low temperature, giving a separation of the intrinsic transit times and charging times involved into the performance limitation. Chapter IV presents noise measurements and the derivation of high frequency noise analytical models. These models highlight the impact of the current crowding and the self-heating effects, and the influence of the base-emitter heterojunction on the high frequency noise. According to these models the high frequency noise performances are estimated at low temperature for both HBT technologies
Botté, Agnès. "Les hôtels particuliers dijonnais de 1610 à 1715." Thesis, Paris 4, 2011. http://www.theses.fr/2011PA040209.
Повний текст джерелаIn the seventeenth century, Dijon, capital of the province, was the place where proposed members of the political, administrative and financial bodies chose to live. The city therefore experienced a remarkable boom in the construction of private residences. The builders were mainly officers of the sovereign courts, members of parliament or advisors to the Board of Auditors who wanted to satisfy their need for social representation by ordering houses worthy of their rank : the private mansion was the illustration of people of power, place both a demonstration of social standing, architectural and artistic.This study, the first synthesis of the private mansions of Dijon from 1610 to 1715, is approached according to three lines of thought: the commissioners, the architects and their constructions. The architectural analysis of mansions which leaves a large part to the distribution, allows the comparison with Paris and other major cities of the parliamentary kingdom
Llerar, Meza Gerónimo. "Upscaling nonreactive solute transport." Doctoral thesis, Universitat Politècnica de València, 2009. http://hdl.handle.net/10251/5848.
Повний текст джерелаLlerar Meza, G. (2009). Upscaling nonreactive solute transport [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5848
Palancia
(8996768), Brooke Renee Cochenour. "Predicting Transit Times For Outbound Logistics." Thesis, 2020.
Знайти повний текст джерелаCochenour, Brooke R. "Predicting transit times for outbound logistics." Thesis, 2020. http://hdl.handle.net/1805/23032.
Повний текст джерелаOn-time delivery of supplies to industry is essential because delays can disrupt production schedules. The aim of the proposed application is to predict transit times for outbound logistics thereby allowing suppliers to plan for timely mitigation of risks during shipment planning. The predictive model consists of a classifier that is trained for each specific source-destination pair using historical shipment, weather, and social media data. The model estimates the transit times for future shipments using Support Vector Machine (SVM). These estimates were validated using four case study routes of varying distances in the United States. A predictive model is trained for each route. The results show that the contribution of each input feature to the predictive ability of the model varies for each route. The mean average error (MAE) values of the model vary for each route due to the availability of testing and training historical shipment data as well as the availability of weather and social media data. In addition, it was found that the inclusion of the historical traffic data provided by INRIXTM improves the accuracy of the model. Sample INRIXTM data was available for one of the routes. One of the main limitations of the proposed approach is the availability of historical shipment data and the quality of social media data. However, if the data is available, the proposed methodology can be applied to any supplier with high volume shipments in order to develop a predictive model for outbound transit time delays over any land route.
Müller, Thomas. "Recharge and residence times in an arid area aquifer." Doctoral thesis, 2012. https://tud.qucosa.de/id/qucosa%3A27074.
Повний текст джерелаEin steigender Bedarf nach landwirtschaftlichen Produkten - und damit Wasser - bei gleichzeitiger Abnahme des verfügbaren Wassers in Qualität und Menge in den bisherigen Anbaugebieten, führt zu einer intensiven Nutzung der Grundwasserressourcen der ariden Najd-Region in der Provinz Dhofar, im Süden des Sultanats Oman. Als Quelle dienen die Grundwasservorräte des Umm Er Radhuma-Aquifers, einer der Hauptaquifere auf der arabischen Halbinsel. Der steigenden Nutzung stehen mit dem jährlichen Monsoon, der regional limitiert ist, und unrgelmässigen, zwischen 3 und 7 Jahren auftretenden Unwettern (Zyklonniederschlag) nur begrenzte Niederschlagsmengen als Quellen für eine mögliche Zufuhr von Wasser (Grundwasserneubildung) zum Aquifersystem gegenüber. Der Ansatz der vorliegenden Arbeit besteht darin, mit Hilfe eines Grundwassermodells und der Einbeziehung von Umweltisotopen das tiefe und zur Nutzung geförderte Grundwasser in der Najd-Region als Teil eines aktiven Fließsystemes zu untersuchen und mittlere Verweilzeiten des Grundwassers abzuleiten. Ein 2D-Grundwassermodell entlang einer Fließlinie vom Dhofar Gebirge im Süden zur Sabkha Umm as Sammim im Nordosten wurde entwickelt. Das Modell reproduziert den Süd-Nord-Gradienten als auch den aufwärts gerichteten Gradienten mit höheren Grundwasserständen in den tiefen Grundwasserleitern. Die Simulationen zeigen, dass der Wechsel von ariden und humiden Phasen (wenig bzw. viel Grundwasserneubildung) zu Veränderungen der Grundwasseroberfläche führt die mehrere tausend Jahre anhalten können. Das kalibrierte Grundwassermodel zeigt, dass mit einer Neubildungsrate von 4 mm a−1 die natürlichen Grundwasserverhältnisse im Najd abgebildet werden können. Dass eine moderne Grundwasserneubildung stattfindet, konnte mittels Loggermessungen anhand steigender Grundwasserstände im tiefen Aquifersystem nach dem Extremunwetter im November 2011 (Zyklon Keila) eindeutig nachgewiesen werden. Die Analyse der 36Cl- und 4He-Konzentrationen zeigt, dass die tiefen Grundwasser im zentralen Najdgebiet bis 550 000 Jahren alt sein können. Das bedeutet allerdings, dass die über 14C Daten berechneten Grundwasseralter mit ca. 20 000 Jahren für das zentrale Najdgebiet und bis zu 35 000 Jahren für den nördlichen Najd, die Grundwasseralter deutlich unterschätzen. Die abnehmenden 36Cl und ansteigenden 4He Konzentrationen zeigen den erwarteten Trend in Grundwasserfließrichtung und können als aussagefähige Tracer für die Bewertung der Verweilzeiten und Alter des fossilen Grundwassers der Najd-Region angesehen werden. Mit Hilfe des Partickeltrackings wurden die Grundwasseralter, basierend auf den Isotopentracern, im Grundwassermodel simuliert. Die Porosität wurde dabei für das Aquifesystem mit Werten zwischen 15 und 20 % bestimmt. Die generierten Parameter und das gewonnene Systemverständnis sind eine wichtige Basis für zukünftige 3D-Modellstudien welche die Verfügbarkeit der Wasserresourcen im Najd untersuchen werden. Weitere Anwendungen für das in dieser Studie aufgebaute 2D-Modell sind Untersuchungen zum Paläoklima und dessen Einfluss auf das Grundwassersystem.
Langkau, Katharina [Verfasser]. "Flows over time with flow dependent transit times / vorgelegt von Katharina Langkau." 2003. http://d-nb.info/968912656/34.
Повний текст джерелаColeman, Anthony M. "Determining the relationship between measured residence time distributions in lateral surface transient storage zones in streams and corresponding physical characteristics." Thesis, 2012. http://hdl.handle.net/1957/35099.
Повний текст джерелаGraduation date: 2013
Elbakkoush, Abdallah Ahmed, and 艾伯樺. "Hepatobiliary transit times of Gadoxetic Acid in Magnetic Resonance Imaging of patients with liver cirrhosis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/75963994034199480462.
Повний текст джерела國立陽明大學
生物醫學影像暨放射科學系
102
Background and Objective: Chronic liver disease and cirrhosis result in about 35,000 deaths each year in the United States. Cirrhosis is the ninth leading cause of death in the United States and is responsible for 1.2% of all US deaths. MRI has been reported to be an excellent imaging modality because of its high tissue contrast and use of tissue-specific contrast agents. Gadoxetic acid (Gd-EOB-DTPA) is a more recently developed liver specific MR imaging contrast agent. The excretion of Gd-EOB-DTPA might be related to the liver disease and liver function. The pur¬pose of this study was to determine transit times for excretion of Gd-EOB-DTPA in the hepatobiliary system in patients with liver cirrhosis1. Material and Methods: Institutional Review Board of our hospital approved the study; in-formed consent was waived. We retrospectively included consecutive patients with liver cirrho¬sis who underwent contrast-enhanced abdominal MR examination after injection of 10 mL Gd-EOB-DTPA at 1.5-T MR from December 2009 to March 2012. Finally, the 47 patients were en-rolled in this study. The Gd-EOB-DTPA-enhanced MRI included arterial phase (18~20sec, arterial phase, AP), por¬tal venous phase (50~55 sec, portal venous phase, PP), venous phase (85~90s, venous phase, VP) and three delayed phases (180s, 20mins and 30mins after the injection of contrast agent). The images were evaluated for the presence of contrast agent in the intra-hepatic bile ducts (IHD), the common bile duct (CBD), the gallbladder and the duodenum in AP, PP, VP and three delay phases. Results: The optimal time of arterial phase was from 15 s after injection, and the optimal time for portal venous imaging was from 40 s after injection. Meanwhile, the optimal time to observe changes was 20 min after contrast initiation of Gd-EOB-DTPA in 39 patients (39/47, 83 %) at the IHD and 37 patients (37/47, 78.5%) at the CBD. Gallbladder reflux was visible in 26 (26/47, 43%), duodenal excretion in 17 patients (17/47, 36%), respectively. After 30 min of contrast injection, Gd-EOB-DTPA could still be detected in 6 patients (6/47, 13 %) at the IHD and 7 patients (7/47, 15 %) at the CBD, and gallbladder reflux was visible in 10 (10/47, 21%), duodenal excretion in 20 patients (26/47, 55%), respectively.(Fig 2 and Fig 3) GB was not visible in 9 patients, 4 out of these 9 patients received cholecystectomy. Conclusion: The results of our study shows that in patients with liver cirrhosis, the excretion of Gd-EOB-DTPA can be observed. Our results also demonstrated that the bilirubin level and the severity of cirrhosis (according to the Child Pugh scores had certain effect on excretion of Gd-EOB-DTPA into biliary tree.
Taei-Tehrani, Mohammad Reza. "Pseudo Random Arterial Modulation (PRAM): A Novel ASL Approach to Measure Flow and Blood Transit Times." Thesis, 2012. https://doi.org/10.7916/D88S4WWC.
Повний текст джерелаMerget, Benjamin. "Computational methods for assessing drug-target residence times in bacterial enoyl-ACP reductases and predicting small-molecule permeability for the \(Mycobacterium\) \(tuberculosis\) cell wall." Doctoral thesis, 2015. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-127386.
Повний текст джерела\textbf{Molekulare Determinanten von Wirkstoff-Angriffsziel Verweilzeiten bakterieller Enoyl-ACP Reduktasen.} In frühen Phasen der Wirkstoffentwicklung sind Optimierungsprozesse häufig affini\-täts\-geleitet. Darüber hinaus sollte zusätzlich die Wirkstoff-Angriffsziel Verweilzeit $t_R$ berücksichtigt werden, da diese oft eine starke Korrelation zur \textit{in vivo} Wirksamkeit der Substanzen aufweist. Rationale Optimierung von $t_R$ ist jedoch auf Grund eines Mangels an struktureller Information über den Übergangszustand der Ligandbindung und Dissoziierung nicht einfach umsetzbar. Die Enoyl-ACP Reduktase FabI der Fettsäurebio\-synthese (FAS) Typ II ist ein wichtiger Angriffspunkt in der Antibiotikaforschung. InhA ist das FabI Enzym des Organismus \textit{Mycobacterium tuberculosis} und kann durch Substanzen diverser Klassen gehemmt werden. Es wird vermutet, dass Hemmung von InhA durch langsam-bindende (``slow-onset'') Inhibitoren mit der Ordnung der flexibelsten Region des Enzyms assoziiert ist, dem Substratbindungsloop (SBL). Diphenylether sind eine InhA Inhibitorenklasse, die eine solche SBL Ordnung fördern und dadurch lange Verweilzeiten im Angriffsziel aufweisen. Obwohl diese Inhibitoren energetisch und kinetisch gut charakterisiert sind, ist noch immer unklar, wie die strukturellen Eigenschaften eines Liganden $t_R$ beeinflussen. Durch die Verwendung klassischer Molekulardynamik (MD) Simulationen wurden wiederkehrende Konformationsfamilien von InhA Protein-Ligand Komplexen entdeckt und strukturelle Determinanten der Wirkstoff-Angriffsziel Verweilzeit von Diphenylethern mit verschiedenen kinetischen Profilen beschrieben. Anhand dieser Ergebnisse wurden Richtlinien zur Wirksamkeitsoptimierung von InhA Inhibitoren abgeleitet, einschließlich einer 5'-Substitution am Diphenylether B-Ring. Die Validität dieses Vorschlags wurde mittels MD Simulationen nachfolgend analysiert. Darüber hinaus wurden ``Steered MD'' (SMD) Simulationen als MD Technik für umfangreicheres Sampling verwendet um die Liganddissoziation von Diphenylethern aus dem FabI Enzym von \textit{Staphylococcus aureus} zu untersuchen. Dieser Ansatz resultierte in einem sehr akkuraten, quantitativen linearen Regressionsmodell der experimentellen Verweilzeit $ln(t_R)$ dieser Inhibitoren als Funktion der berechneten maximalen freien Energieänderung induzierter Ligandextraktion. Dieses Modell kann genutzt werden um die Verweilzeiten neuer potentieller Inhibitoren aus Kristallstrukturen oder validen Dockingposen vorherzusagen. Die korrekte strukturelle Charakterisierung des intermediären und des finalen Zustandes (EI und EI*-Zustand) eines Enzym-Inhibitor Komplexes bei einem zweistufigen Inhibitionsmechanismus durch langsam-bindende Hemmstoffe ist essentiell für rationale Verweilzeitoptimierung. Daher wurde die gegenwärtige Ansicht des EI und EI*-Zustandes von InhA mittels Kristallstrukturanalyse, MD und SMD Simulationen erneut aufgegriffen. Insgesamt bestätigten die Analysen, dass der EI*-Zustand einer Konformation ähnlich der 2X23 Kristallstruktur (mit langsam-bindenden Inhibitor \textbf{PT70}) gleicht, während eine Drehung der Reste Ile202 und Val203 mit einer weiter geöffneten Helix $\alpha 6$ dem EI-Zustand entspricht. Des Weiteren zeigten MD Simulationen den Einfluss naher Kristallkontakte zu Symmetrie-Nachbarn in der SBL Region auf die SBL Stabilität. Dies wird durch die Beobachtung hervorgehoben, dass die Ketten A und B' eines InhA-\textbf{PT155}-Komplexes und des angrenzenden Symmetrie-Nachbars, welche in engem Kontakt in der SBL Region stehen, signifikant stabilere SBLs aufweisen, als die Ketten A und B in einer Simulation des Tetramers. Zum Abschluss von Teil I wurden SMD Simulationen angewandt, auf deren Basis es möglich war, langsam-bindende InhA Inhibitoren von schnell-reversiblen (``rapid reversible'') Liganden zu unterscheiden. \textbf{Vorhersage von \textit{Mycobacterium tuberculosis} Zellwand Permeabilität.} Die Zellwand von \textit{M.~tuberculosis} erschwert die antimycobakterielle Wirkstofffindung auf Grund ihrer einzigartigen Zusammensetzung und bietet eine intrinsische Antibiotikaresistenz gegenüber lipophilen und hydrophilen Substanzen. Um den chemischen Raum wirkstoffähnlicher Moleküle gegen diesen Erreger (``Druggability Space'') einzugrenzen, wurde eine groß angelegte Dataminingstudie durchgeführt, welche auf multivariater statistischer Analyse der Unterschiede der physikochemischen Zusammensetzung eines normalverteilten wirkstoffähnlichen chemischen Raumes und einer Datenbank von antimycobakteriellen -- und somit höchstwahrscheinlich permeablen -- Substanzen beruht. Dieser Ansatz resultierte in dem logistischen Regressionsmodell MycPermCheck, welches in der Lage ist die Permeabilitätswahrscheinlichkeit kleiner organischer Moleküle anhand ihrer physikochemischen Eigenschaften vorherzusagen. Die Evaluation von MycPermCheck deutet auf eine große Vorhersagekraft hin. Das Modell wurde als frei zugänglicher online Service und als lokale Kommandozeilenversion implementiert. Methodiken und Ergebnisse aus beiden Teilen dieser Dissertation wurden kombiniert um ein virtuelles Screening nach antimycobakteriellen Substanzen durchzuführen. Myc\-PermCheck wurde verwendet um den chemischen Permeabilitätsraum von \textit{M.~tuberculosis} anhand der gesamten ZINC12 Datenbank wirkstoffähnlicher Moleküle abzuschätzen. Nach weiteren Filterschritten mit Bezug auf ADMET Eigenschaften, wurde InhA als exemplarisches Angriffsziel ausgewählt. Docking nach InhA führte schließlich zu einer Treffersubstanz, welche in darauffolgenden Schritten weiter optimiert wurde. Die Interaktionsqualität ausgewählter Derivate mit InhA wurde daraufhin mittels MD und SMD Simulationen in Bezug auf Protein und Ligand Stabilität, sowie auch der maximalen freien Energieänderung induzierter Ligandextraktion, untersucht. Die Ergebnisse der vorgestellten computerbasierten Experimente legen nahe, dass Substanzen mit einem Indol-3-Acethydrazid Gerüst eine neuartige Klasse von InhA Inhibitoren darstellen könnten. Weiterführende Untersuchungen könnten sich somit als lohnenswert erweisen
Mahmood, Muhammad Nasir. "Modeling the effects of Transient Stream Flow on Solute Dynamics in Stream Banks and Intra-meander Zones". 2019. https://tud.qucosa.de/id/qucosa%3A74858.
Повний текст джерелаKern, Jamie M. "Timescales of large silicic magma systems : investigating the magmatic history of ignimbrite eruptions in the Altiplano-Puna Volcanic Complex of the Central Andes through U-Pb zircon dating." Thesis, 2012. http://hdl.handle.net/1957/30153.
Повний текст джерелаGraduation date: 2012
"Consequences of Short Term Mobility Across Heterogeneous Risk Environments: The 2014 West African Ebola Outbreak." Doctoral diss., 2018. http://hdl.handle.net/2286/R.I.49363.
Повний текст джерелаDissertation/Thesis
Doctoral Dissertation Applied Mathematics 2018
Duarte, António A. L. Sampaio. "Influência da hidrodinâmica em sistemas estuarinos sujeitos a eutrofização." Doctoral thesis, 2006. http://hdl.handle.net/1822/5914.
Повний текст джерелаOs estuários são sistemas hídricos que desde sempre favoreceram o desenvolvimento de aglomerados urbanos importantes, por propiciarem actividades com grande impacto sócio-económico, nomeadamente a portuária, a piscatória e as de lazer. As águas estuarinas, resultantes da confluência de águas fluviais e marinhas, com regimes hidrodinâmicos peculiares, revelam-se favoráveis à retenção de nutrientes tornando-se muito vulneráveis a factores de stress ambiental, que podem por em causa o equilíbrio destes ecossistemas aquáticos. Os processos de eutrofização podem originar florescências algais, alterando a biodiversidade e a estrutura trófica dos sistemas hídricos, provocando a depleção do oxigénio dissolvido até níveis que podem comprometer a utilização dessas águas para os seus diferentes usos. Tendo-se constatado, através da análise dos dados recolhidos na última década no estuário do rio Mondego, que as condições hidrodinâmicas influenciam decisivamente a ocorrência de episódios de proliferação intensa de macroalgas infestantes nesse sistema, procedeu-se neste trabalho ao desenvolvimento de uma metodologia hidroinformática para o estudo integrado das interacções entre o comportamento hidrodinâmico dos sistemas estuarinos e as alterações da sua qualidade ecológica, com especial interesse na mitigação dos processos de eutrofização. Após a caracterização dos processos físicos, químicos e biológicos dos ambientes estuarinos e a abordagem das capacidades dos modelos matemáticos de qualidade da água, procedeu-se a uma caracterização da área de estudo, o estuário do rio Mondego, com especial relevo para a análise dos resultados das campanhas de monitorização efectuadas para avaliar o estado trófico do seu braço sul, sujeito, nas últimas décadas a um processo de eutrofização. O ambiente hidroinformático desenvolvido (modelo MONDEST), integra vários módulos (hidrodinâmico, transporte e tempo de residência) e apresenta uma metodologia inovadora de abordagem do cálculo do tempo de residência em sistemas estuarinos, quer em termos conceptuais, quer na definição da sua variabilidade espacial, rompendo, assim, com a habitual adopção de um valor único desta grandeza para tipificar um determinado estuário. Procedeu-se neste trabalho à caracterização do comportamento hidrodinâmico do todo o sistema estuarino, de modo a avaliar as distribuições espaciais e temporais de duas grandezas - salinidade e tempo de residência - com influência directa na produção primária e, consequentemente, na vulnerabilidade do estuário do rio Mondego à eutrofização, dando um contributo para a selecção criteriosa das medidas e das práticas de gestão mais adequadas à salvaguarda do bom estado ecológico deste importante ecossistema, bem como ao desenvolvimento ambientalmente sustentável das actividades sócio-económicas predominantes no Baixo Mondego.
The south arm of Mondego estuary, located in the central western Atlantic coast of Portugal, is stressing by an eutrophication process due to massive nutrient loading from urbanised areas and diffusive runoff from intensively agricultural areas. As a consequence of nutrient enrichment, a structural change of the ecosystem has been taking place and so the opportunistic macroalgae growth was strongly stimulated allowing the occurrence of macroalgae blooms and the extinction of seagrass in more shallow areas. This situation may result in anoxic system collapse, with the development of hydrogen-sulphide conditions, lethal to rooted macrophytes such as Zostera spp. It becomes crucial to obtain information on the mechanisms that regulate the abundance of opportunistic macroalgae and its spatial and temporal distribution. Depending on the tidal amplitude, depth, current velocity, wind and wave-induced vertical turbulence, plants growing in shallow areas are suspended in the water column and transported out of the system. In the last decade a major effort has been done in integrating hydrodynamic and water quality models for estuarine environments. The analysis of available field data, obtained in this system from water column and benthos over the last twenty years, allows concluding that the occurrence of green macroalgal blooms is strongly dependent on the hydrodynamic conditions, residence time and salinity gradients. So, a hydroinformatic tool (MONDEST model) was developed and hydrodynamic modelling of Mondego estuary had been implemented in order to estimate and evidence the influence of residence time, current velocity and salinity spatial distribution on eutrophication process of Mondego estuary at different simulated scenarios and discharges characteristics. The results obtained for the spatial distribution of residence time and salinity confirm real eutrophication gradients of Mondego estuary south arm. This model (hydrodynamic, water quality and residence time calculation) constitutes a very powerful method for enhancing systems eutrophication vulnerability assessment in order to establish the best water quality management practices for the environmental sustainability of this important aquatic ecosystem.
(5930639), Carolyn L. Gleason. "LIFE IN THE RAIN SHADOW: UNDERSTANDING SOURCES OF RECHARGE, GROUNDWATER FLOW, AND THEIR EFFECTS ON GROUNDWATER DEPENDENT ECOSYSTEMS IN THE PANAMINT RANGE, DEATH VALLEY, CALIFORNIA, USA." Thesis, 2019.
Знайти повний текст джерелаDespite its location in the rain shadow of the southern Sierra Nevada, the Panamint Range within Death Valley National Park, CA hosts a complex aquifer system that supports numerous springs. These springs, in turn, support unique groundwater-dependent ecological communities. Spring emergences range in elevation from 2434 m above sea level (within the mountain block) to 77 m below sea level (in the adjacent basins). Waters were collected from representative Panamint Range springs and analyzed for environmental isotopes and geochemical tracers to address the following questions: 1) What is the primary source of recharge for the springs? How much recharge occurs on the Panamint Range? 2) What groundwater flowpaths and geologic units support springflow generation? and 3) What are the residence times of the springs? The stable isotopic composition (δ18O and δ2H) of spring water and precipitation indicate that localized high-elevation snowmelt is the dominant source of recharge to these perennial springs, though recharge from rainfall is not wholly insignificant. Geochemical evolution was evaluated using principle component analysis to compare the concentrations of all major spring cations and anions in a multidimensional space and group them according to dominant geochemical signatures. These resulting geochemical groups are controlled primarily by topography. The Noonday Dolomite and other carbonate units in the range are identified as the water-bearing units in the mountain block based on the 87Sr/86Sr of spring waters and rock samples. These units also offer higher hydraulic conductivities than other formations and are chemically similar. Radiocarbon- and 3H derived residence times of these spring waters range from modern to approximately 1840 years, with the shortest residence times at higher altitudes and Hanaupah Canyon and increasing residence times with decreasing altitude. This residence time-altitude relationship is likewise likely topography-driven though there are significant disparities in mountain block storage between the various canyons of the range resulting in variable residence times between drainages. Lower Warm Springs A and B, however, are the exceptions to this trend as they emerge at lower altitudes (750m above sea level) and are likely driven by the transport of groundwater to the surface along faults which increases both the temperature and groundwater residence times of waters from these springs. Benthic macroinvertebrates and benthic and planktonic microbes were also sampled for each spring studied. BMI and microbial community structure in the Panamint Range is likewise topography-controlled with more tolerant communities at lower elevations (within more chemically evolved waters) and less tolerant species in the unevolved waters at higher elevations.
Vaz, Filipe Martins. "Estudo dos congestionamentos e tempos de espera duma empresa de transportes metropolitana." Master's thesis, 2019. http://hdl.handle.net/10071/19683.
Повний текст джерелаRapid Transit is a connected rail transport system that does not share its line with other transport systems or companies, having an exclusive line. It therefore allows for a better regularization of supply, thus having lower lead times compared to other rail systems. Due to overcrowding and waiting times that the subway has that may change the quality of service, it was decided to study them in Metro de Lisboa. Due to planification of a formation of a circular line, it was study the waiting times and overcrowding of the red line, the current line that have a connection with all other lines. To do so, it was chosen to do via the use of a computer simulation feature, that has advantages of high computing power and allow accurate prediction. With the number of entrances and exits per station, day of the week and time period received by Metro and time interval between trains, it was possible to calculate the number of passengers on the platform and carriages in each minute and the waiting time of each passenger until entering the carriage and the minute this entry occurred. With these data, it was concluded that, in both congestion and waiting times, there is a difference between the stations (having more overcrowding the stations that connects with all the other lines and Oriente), days of the week (mainly between working days and weekends) and time period (with morning and afternoon rush having more demand and night with longer waiting time).