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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

ELECTRONIC SIMULATION IN CONSTRUCTION

SINGH, ARUN K. 11 March 2002 (has links)
No description available.
12

A mathematical simulation of ETS' limestone emission control (LEC) process using a moving bed configuration

Reddy, Shailendra N. January 1991 (has links)
No description available.
13

Utilização de simulador matemático comparativamente ao analógico nos estudos de manobra portuária. / Use of mathematical simulator comparativily to the analogical one in the studies of port maneuver.

Villote, Joffre 10 September 2010 (has links)
O Simulador Híbrido, unindo um modelo Numérico a um modelo analógico proporcionará resultados bastantes realísticos alcançados em avaliação de risco pertinente a desenvolvimentos de projetos de Engenharia onde as manobras de navios de todos os portes, com aumento de fluxos de embarcações futuras se torna cada vez mais necessária. A busca pela qualidade, a garantia e a sustentabilidade destes tipos de projetos, quase sempre de alto custo, faz deste Simulador a ferramenta mais importante neste desafio, pois poderá ser avaliado o somatório das vantagens e desvantagens que afetam ambas as ferramentas, chegando a um nível ideal de simulação, contendo critérios de amarração, com tipos de cabos dos navios adequados, sob quaisquer condições de maré e outras atipicidades dos terminais. Este trabalho tem por objetivo mostrar que o Simulador Híbrido levará à otimização da operação portuária, garantindo o alto nível da segurança por elas efetuado, diminuindo custos inerentes substanciais para a empresa contratante, através da demonstração de cases apresentados e embasamento teórico. / The Hybrid Simulator, joining a mathematical model to an analogical model will provide resulted sufficiently realistic reached in evaluation of pertinent risk the developments of projects of Engineering where the maneuvers of ships of all the transports, with increase of flows of future boats if become each more necessary time. The search for the quality, the guarantee and the support of these types of projects, almost always of high cost, makes of this Simulator the tool most important in this challenge, therefore the many of the advantages could be evaluated and disadvantages that affect both the tools, arriving in an ideal level of simulation, I contend knotting criteria, with types of handles of the adjusted ships, under any conditions of tide and other atipics of the terminals. This work has for objective to show that the Hybrid Simulator will lead to the otimization of the port operation, guaranteeing the high level of the security for effected them, diminishing substantial inherent costs for the contracting company, through the demonstration of you marry presented and theoretical basement.
14

Utilização de simulador matemático comparativamente ao analógico nos estudos de manobra portuária. / Use of mathematical simulator comparativily to the analogical one in the studies of port maneuver.

Joffre Villote 10 September 2010 (has links)
O Simulador Híbrido, unindo um modelo Numérico a um modelo analógico proporcionará resultados bastantes realísticos alcançados em avaliação de risco pertinente a desenvolvimentos de projetos de Engenharia onde as manobras de navios de todos os portes, com aumento de fluxos de embarcações futuras se torna cada vez mais necessária. A busca pela qualidade, a garantia e a sustentabilidade destes tipos de projetos, quase sempre de alto custo, faz deste Simulador a ferramenta mais importante neste desafio, pois poderá ser avaliado o somatório das vantagens e desvantagens que afetam ambas as ferramentas, chegando a um nível ideal de simulação, contendo critérios de amarração, com tipos de cabos dos navios adequados, sob quaisquer condições de maré e outras atipicidades dos terminais. Este trabalho tem por objetivo mostrar que o Simulador Híbrido levará à otimização da operação portuária, garantindo o alto nível da segurança por elas efetuado, diminuindo custos inerentes substanciais para a empresa contratante, através da demonstração de cases apresentados e embasamento teórico. / The Hybrid Simulator, joining a mathematical model to an analogical model will provide resulted sufficiently realistic reached in evaluation of pertinent risk the developments of projects of Engineering where the maneuvers of ships of all the transports, with increase of flows of future boats if become each more necessary time. The search for the quality, the guarantee and the support of these types of projects, almost always of high cost, makes of this Simulator the tool most important in this challenge, therefore the many of the advantages could be evaluated and disadvantages that affect both the tools, arriving in an ideal level of simulation, I contend knotting criteria, with types of handles of the adjusted ships, under any conditions of tide and other atipics of the terminals. This work has for objective to show that the Hybrid Simulator will lead to the otimization of the port operation, guaranteeing the high level of the security for effected them, diminishing substantial inherent costs for the contracting company, through the demonstration of you marry presented and theoretical basement.
15

A mathematical simulation of ETS' limestone emission control process using the method of characteristics: Fixed-bed configuration/gas-phase mass transport control

Appell, Kenneth William January 1989 (has links)
No description available.
16

Predator-prey dynamics under the influence of exogenous and endogenous regulation : a data-based modeling study on spring plankton with respect to climate change

Tirok, Katrin January 2008 (has links)
Understanding the interactions of predators and their prey and their responses to environmental changes is one of the striking features of ecological research. In this thesis, spring dynamics of phytoplankton and its consumers, zooplankton, were considered in dependence on the environmental conditions in a deep lake (Lake Constance) and a shallow marine water (mesocosms from Kiel Bight), using descriptive statistics, multiple regression models, and process-oriented dynamic simulation models. The development of the spring phytoplankton bloom, representing a dominant feature in the plankton dynamics in temperate and cold oceans and lakes, may depend on temperature, light, and mixing intensity, and the success of over-wintering phyto- and zooplankton. These factors are often correlated in the field. Unexpectedly, irradiance often dominated algal net growth rather than vertical mixing even in deep Lake Constance. Algal net losses from the euphotic layer to larger depth were induced by vertical mixing, but were compensated by the input from larger depth when algae were uniformly distributed over the water column. Dynamics of small, fast-growing algae were well predicted by abiotic variables, such as surface irradiance, vertical mixing intensity, and temperature. A simulation model additionally revealed that even in late winter, grazing may represent an important loss factor of phytoplankton during calm periods when losses due to mixing are small. The importance of losses by mixing and grazing changed rapidly as it depended on the variable mixing intensity. Higher temperature, lower global irradiance and enhanced mixing generated lower algal biomass and primary production in the dynamic simulation model. This suggests that potential consequences of climate change may partly counteract each other. The negative effect of higher temperatures on phytoplankton biomass was due to enhanced temperature-sensitive grazing losses. Comparing the results from deep Lake Constance to those of the shallow mesocosm experiments and simulations, confirmed the strong direct effect of light in contrast to temperature, and the importance of grazing already in early spring as soon as moderate algal biomasses developed. In Lake Constance, ciliates dominated the herbivorous zooplankton in spring. The start of ciliate net growth in spring was closely linked to that of edible algae, chlorophyll a and the vertical mixing intensity but independent of water temperature. The duration of ciliate dominance in spring was largely controlled by the highly variable onset of the phytoplankton bloom, and little by the less variable termination of the ciliate bloom by grazing of meta-zooplankton. During years with an extended spring bloom of algae and ciliates, they coexisted at relatively high biomasses over 15-30 generations, and internally forced species shifts were observed in both communities. Interception feeders alternated with filter feeders, and cryptomonads with non-cryptomonads in their relative importance. These dynamics were not captured by classical 1-predator-1-prey models which consistently predict pronounced predator-prey cycles or equilibria with either the predator or the prey dominating or suppressed. A multi-species predator-prey model with predator species differing in their food selectivity, and prey species in their edibility reproduced the observed patterns. Food-selectivity and edibility were related to the feeding and growth characteristics of the species, which represented ecological trade-offs. For example, the prey species with the highest edibility also had the highest maximum growth rate. Data and model revealed endogenous driven ongoing species alternations, which yielded a higher variability in species-specific biomasses than in total predator and prey biomass. This holds for a broad parameter space as long as the species differ functionally. A more sophisticated model approach enabled the simulation of a continuum of different functional types and adaptability of predator and prey communities to altered environmental conditions, and the maintenance of a rather low model complexity, i.e., low number of equations and free parameters. The community compositions were described by mean functional traits --- prey edibility and predator food-selectivity --- and their variances. The latter represent the functional diversity of the communities and thus, the potential for adaptation. Oscillations in the mean community trait values indicated species shifts. The community traits were related to growth and grazing characteristics representing similar trade-offs as in the multi-species model. The model reproduced the observed patterns, when nonlinear relationships between edibility and capacity, and edibility and food availability for the predator were chosen. A constant minimum amount of variance represented ongoing species invasions and thus, preserved a diversity which allows adaptation on a realistic time-span. / Eine der großen Herausforderungen der heutigen ökologischen Forschung ist es, Veränderungen von Ökosys­temen vorher­zusagen, die mit dem Klimawandel einhergehen. Dafür sind ein umfassendes Verständnis der ver­schiedenen Steuerungsfaktoren des entsprechenden Systems und Kenntnisse zur Anpassungs­fähigkeit des Systems nötig. Auf der Grundlage dieses Wissens, können mit mathemati­schen Modellen Klima­szenarien gerechnet und Vorhersagen erstellt werden. Die vorliegende Arbeit untersuchte die Regulation des Phytoplanktons (kleine freischwebende einzellige Algen) und seiner Konsumenten (Zooplankton, tierische Kleinstlebewesen) sowie deren Wechselspiel während des Frühjahrs mit Bezug auf den Klimawandel. Als Basis dienten langjährige Daten von einem großen tiefen See (Bodensee) sowie Daten von Versuchen mit Organis­men aus einem flachen marinen Ge­wässer (Kieler Förde, Ostsee). Diese Daten wurden mit statistischen Verfahren und mathematischen Modellen ausge­wertet. In Gewässern sind Algen als Primärproduzenten die Nahrungsgrundlage für tieri­sche Organismen bis hin zu Fischen und Meeresfrüchten, und bestimmen die Wasserqualität der Ge­wässer. Daher ist es wichtig zu verstehen, welche Mechanismen die Dynamik der Algen steuern. Der Grundstein für die saisonale Entwicklung von Phyto- und Zooplankton in Gewässern un­serer Breiten wird mit dem Be­ginn des Wachstums im Frühjahr gelegt. Diese Arbeit zeigt, dass es bereits im zeitigen, noch kalten Frühjahr ein Wechselspiel physikalischer und biologischer Steuerungsmechanismen für die Algenent­wicklung gibt. Physikalische Faktoren sind die Wassertemperatur, die Globalstrahlung und die Durchmischung des Gewässers, die durch die Stärke des Windes beeinflusst wird. All diese Steue­rungsmechanismen sind eng miteinander verwoben und werden unterschiedlich stark vom Klimawan­del beeinflusst. Mit mathematischen Modellen gelang es den Einfluss einzelner Faktoren voneinander zu trennen und zu zeigen, dass Effekte durch den Klimawandel sich gegenseitig aufheben oder aber auch verstärken können. Schon geringe Änderungen an der Basis der Nahrungsnetze können weitrei­chende Auswirkungen auf höhere Ebenen habe. Wie stark diese Auswirkungen im Einzelnen sind, hängt entscheidend von der Anpassungsfähigkeit gesamter Ökosysteme und ihrer Artengemeinschaf­ten sowie einzelner Individuen ab. Beispielsweise reagiert die Algengemeinschaft auf einen starken Fraßdruck ihrer Räuber mit einer Verschiebung zu weniger gut fressbaren Algenarten. Diese weniger gut fressbaren Arten unterscheiden sich jedoch auch in anderen Eigenschaften, wie zum Beispiel der Ressourcenausnutzung, von besser fressbaren Algen. In dieser Arbeit wurden Modellansätze entwi­ckelt, die diese Fähigkeit zur Anpassung berücksichtigen. Auf dieser Grundlage und mit Einbeziehung der physikalischen Steuerungsfaktoren können Klimaszenarien gerechnet werden und Vorhersagen für den Einfluss des Klimawandels auf unsere Gewässer gemacht werden, die letztlich auch Perspektiven für Handlungsmöglichkeiten aufzeigen.
17

Avaliação de modelos matemáticos para dimensionamento do bulbo molhado na irrigação por gotejamento / Evaluation of mathematical models for wet bulb design in drip irrigation

Sato, Lucas Massayuki 30 March 2012 (has links)
Made available in DSpace on 2016-06-02T18:55:23Z (GMT). No. of bitstreams: 1 4272.pdf: 2401909 bytes, checksum: 472e7aaca2322a7de8b1b169aa30fdd5 (MD5) Previous issue date: 2012-03-30 / Financiadora de Estudos e Projetos / The increasing current demand of water has caused conflicts between their multiple uses, being the agriculture responsible for the use of the largest portion of this natural resource. In this context, drip irrigation has shown growth in irrigated area due to their potential to achieve high efficiency in water application. Drip irrigation is characterized by the application of small volumes of water at high frequency directly in the root zone of plants, helping to maintain soil moisture near field capacity in a given volume of soil usually called the wet bulb. Knowing the dimensions of the wetted generated to be used in drip irrigation project is of fundamental importance for the proper design and operation of drip irrigation systems. The objective of this study was to test the performance of the mathematical models Schwartzman and Zur Reprinted and HYDRUS-2D in predicting dimensions of wet bulb generated generated by emitters of different flow flow rates. In its first part, held at the experimental field of Taubate University, were collected the dimensions of the wet bulbs generated by drip of 2, 4 and 8 L h-1 in a dystrophic red-yellow. In the second, were simulated the dimensions of wet bulb using Schwartzman and Zur Reprinted and HYDRUS-2D models. Statistical analysis used to evaluate the performance of these models have shown that the model Schwartzman Zur Reproduced predicted the experimental data set with an accuracy of 94%, whereas in the case of model HYDRUS-2D, this accuracy was 85%. It was concluded that the two studied models can adequately estimate the dimensions of the wet bulb, for the studied conditions, highlighting, however, that the model performed better was Schwartzman-Zur Reprinted. / A crescente demanda de água tem originado conflitos entre seus usos múltiplos, sendo a agricultura responsável pela utilização da maior parcela deste recurso natural. Neste quadro, a irrigação por gotejamento tem apresentado crescimento em área irrigada devido a sua potencialidade de obter alta eficiência na aplicação de água. A irrigação por gotejamento é caracterizada pela aplicação de pequenos volumes de água em alta frequência diretamente na zona radicular das plantas, permitindo manter a umidade do solo próxima a sua capacidade de campo em um determinado volume de solo denominado normalmente de bulbo molhado. O conhecimento das dimensões do bulbo molhado gerado pelo gotejador a ser utilizado no projeto de irrigação é de fundamental importância para o correto dimensionamento e operação dos sistemas de irrigação por gotejamento. O objetivo deste trabalho foi testar o desempenho dos modelos Schwartzman-Zur Reproduzido e HYDRUS-2D na previsão das dimensões dos bulbos molhados gerados por gotejadores de diferentes vazões. Na sua primeira parte, realizada na área experimental da Universidade de Taubaté, foram coletadas as dimensões dos bulbos molhados gerados por gotejadores de 2, 4 e 8 L.h-1 em um Latossolo vermelhoamarelo. Na segunda, foram simuladas as dimensões dos bulbos molhados utilizando-se os modelos matemáticos Schwartzman-Zur Reproduzido e HYDRUS-2D. Os estudos estatísticos utilizados para avaliar o desempenho desses modelos mostraram que o modelo de Schwartzman-Zur Reproduzido ajustou os dados experimentais com precisão de 94%, enquanto que, no caso do modelo HYDRUS-2D, esta precisão foi de 85%. Concluiu-se que os dois modelos estudados podem estimar adequadamente as dimensões do bulbo molhado para as condições estudadas, destacando-se, porém, que o modelo que apresentou melhor desempenho foi o de Schwartzman-Zur Reproduzido.
18

Uplatnění metod operační analýzy při optimalizaci dopravy / Exercise of operational analysis methods in transport optimalization

KUČEROVÁ, Lucie January 2008 (has links)
In my dissertation I use mathematical simulation of the transport situation for proposal the optimal routing between suppliers and customers. Target of my work is to propose optimal wagon stock.
19

Développement d'une procédure originale pour la multi-détection de composés toxiques utilisant des biocapteurs à base d'acétylcholinestérase / Development of an original procedure for toxic compounds multi-detectionusing an acetylcholinesterase-based biosensors

Stepurska, Kateryna 03 June 2016 (has links)
Les travaux présentés dans ce manuscrit concernent le développement d‘une approche originale permettant la détermination de plusieurs composés (principalement aflatoxines et pesticides organophosphorés), à l‘aide de biocapteurs électrochimiques basés sur l‘inhibition de l‘acétylcholinestérase. Dans un premier temps, un nouveau biocapteur potentiométrique utilisant des transistors à effet de champ sensibles au pH (pH-FETs) comme transducteurs a été développé pour la détermination de l‘aflatoxine B1 (AFB1) et différent paramètres d‘élaboration et de fonctionnement du biocapteur ont été optimisés. Le biocapteur proposé est caractérisé par une stabilité opérationnelle élevée and bonne reproductibilité du signal en cours d‘utilisation et de stockage. Le biocapteur a ensuite été évalué pour l‘analyse d‘échantillons réels (blé, sésame, noix et pois) et une simulation mathématique de la réponse du biocapteur potentiométrique à l‘AFB1 a été proposée pour la première fois et validée. Dans un deuxième temps, un biocapteur conductimétrique utilisant des microélectrodes interdigitées en or a été développé. La sensibilité de ce biocapteur aux aflatoxines ainsi qu‘à d‘autres classes de substances toxiques, tels que les pesticides organophosphorés, les métaux lourds, les glycoalkaloïdes, et les surfactants, a été déterminée. Une nouvelle procédure originale, permettant la détermination sélective de toxines multiclasses par application successive de solutions de réactivation visant spécifiquement des inhibiteurs irréversibles ou réversibles, a été finalement proposée. En utilisant cette méthode, il a été montré que les biocapteurs enzymatiques pouvaient être appliqués à l‘analyse des aflatoxines et des pesticides organophosphorés, ainsi qu‘à la détermination de la toxicité globale des échantillons / Investigations reported in this manuscript are focused on the development of an original approach for the detection of several toxic compounds, mainly aflatoxins and organophosphorus pesticides, using acetylcholinesterase (AChE)-based inhibitory electrochemical biosensors. In a first step, a new potentiometric biosensor using pH Sensitive Field-Effect Transistors (pH-FETs) as transducers was investigated for aflatoxin B1 (AFB1) determination and different elaboration and working parameters were optimized. The proposed biosensor was characterized by high operational stability and reproducibility of the signal during the work as well as during the storage. The biosensor was further evaluated for real samples analysis (wheat, sesame, walnuts and peas) and a mathematical simulation of the potentiometric biosensor response to aflatoxin B1 was proposed for the first time and validated. In a second step, a conductometric biosensor using interdigitated gold microelectrodes was developed. The sensitivity of the biosensor to aflatoxins and other classes of toxic substances, such as organophosphorus pesticides, heavy metals ions, glycoalkaloids, and surfactants, was determined. A new and original procedure, enabling the selective determination of multiclass toxins by applying successive reactivation solutions targeting either irreversible or reversible inhibitors, was finally proposed. Using this method, the electrochemical enzyme inhibitory biosensors could be applied to the analysis of aflatoxins and organophosphorus pesticides, as well as for the determination of total toxicity of the samples
20

Insights into the mechanism of Tau polymerization and the effects of small molecules

Congdon, Erin Elizabeth 06 August 2007 (has links)
No description available.

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