Дисертації: "Point source analysis"

1

Fulford, Ross Anthony. "Structure-borne sound power and source characterisation in multi-point-connected systems." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284262.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Xu, Yang. "Performance Analysis of Point Source Model with Coincident Phase Centers in FDTD." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/214.

Повний текст джерела

Анотація:

The Finite Difference Time Domain (FDTD) Method has been a powerful tool in numerical simulation of electromagnetic (EM) problems for decades. In recent years, it has also been applied to biomedical research to investigate the interaction between EM waves and biological tissues. In Wireless Body Area Networks (WBANs) studies, to better understand the localization problem within the body, an accurate source/receiver model must be investigated. However, the traditional source models in FDTD involve effective volume and may cause error in near field arbitrary direction. This thesis reviews the basic mathematical and numerical foundation of the Finite Difference Time Domain method and the material properties needed when modeling a human body in FDTD. Then Coincident Phase Centers (CPCs) point sources models have been introduced which provide nearly the same accuracy at the distances as small as 3 unit cells from the phase center. Simultaneously, this model outperforms the usual sources in the near field when an arbitrary direction of the electric or magnetic dipole moment is required.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Towler, Jerry Alwynne. "Autonomous Aerial Localization of Radioactive Point Sources via Recursive Bayesian Estimation and Contour Analysis." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43465.

Повний текст джерела

Анотація:

The rapid, accurate determination of the positions and strengths of sources of dangerous radioactivity takes high priority after a catastrophic event to ensure the safety of personnel, civilians, and emergency responders. This thesis presents approaches and algorithms to autonomously investigate radioactive material using an unmanned aerial vehicle.
Performing this autonomous analysis comprises five major steps: ingress from a base of operations to the danger zone, initial detection of radioactive material, measurement of the strength of radioactive emissions, analysis of the data to provide position and intensity estimates, and finally egress from the area of interest back to the launch site. In all five steps, time is of critical importance: faster responses promise potentially saved lives.
A time-optimal ingress and egress path planning method solves the first and last steps. Vehicle capabilities and instrument sensitivity inform the development of an efficient search path within the area of interest. Two algorithmsâ a grid-based recursive Bayesian estimator and a novel radiation contour analysis methodâ are presented to estimate the position of radioactive sources using simple gross gamma ray event count data from a nondirectional radiation detector. The latter procedure also correctly estimates the number of sources present and their intensities.
Ultimately, a complete unsupervised mission is developed, requiring minimal initial operator interaction, that provides accurate characterization of the radiation environment of an area of interest as quickly as reasonably possible.
Master of Science

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Raine, Teresa Jeannette 1976. "Modeling and analysis of non-point source runoff and best management practice devices in Acton, MA." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80167.

Повний текст джерела

Анотація:

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.
Includes bibliographical references (leaves 33-35).
by Teresa Jeannette Raine.
M.Eng.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Alagoz, Eda. "Kinetic Analysis Of Glucose-6-phosphate Branch Point In Saccharomyces Cerevisiae." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606556/index.pdf.

Повний текст джерела

Анотація:

Glycolysis is the main metabolic route in Saccharomyces cerevisiae and it is the sequence of enzyme catalyzed reactions that oxidatively convert glucose to pyruvic acid in the yeast cytoplasm. In addition to the basic steps, glycolysis involves branch points providing the intermediary building blocks of the cell (i.e amino acids and nucleotides). One of these pathways is glucose-6-phosphate branch point which is a junction of glycolytic pathway and pentose phosphate pathway. At this point glucose-6-phosphate can be converted to fructose-6-phosphate a metabolite of glycolytic pathway by phosphoglucoisomerase or it can be dehydrogenated to 6-phosphogluconolactone by glucose-6-phosphate dehydrogenase which is the first enzyme of the pentose phosphate pathway. In this study, the influence of different nitrogen sources on the flux distribution through the pentose phosphate pathway and glycolysis in Saccharomyces cerevisiae was examined. For this purpose, four different compositions of nitrogen sources were used in growth media. The growth medium contained one of the following composition of nitrogen sources
only ammonium sulfate, only yeast nitrogen base, ammonium sulfate and histidine, yeast nitrogen base and histidine. Histidine was added because its synthesis branches from pentose phosphate pathway. In order to analyse the effect of the different compositions of nitrogen sources on the physiology of the yeast, specific activities of hexokinase, phosphoglucose isomerase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase enzymes were measured in the crude extracts of the biomass samples taken in the late exponential phase of the cultures. Addition of histidine caused an increase in the specific activities of all the enzymes analysed in medium containing ammonium sulfate. The specific activity of hexokinase, phosphoglucose isomerase and glucose-6-phosphate dehydrogenase in medium containing yeast nitrogen base and histidine were higher than medium containing yeast nitrogen base. However, the specific activity of 6-phosphogluconate dehydrogenase decreased 3.1% in medium containing yeast nitrogen base and histidine medium with respect to medium with only yeast nitrogen base. The OD value and dry weight in the culture containing histidine aminoacid was higher than the cultures contaning only ammonium sulfate and only yeast nitrogen base. Also the period of the exponential phase was shorter in medium containing ammonium sulfate and histidine and yeast nitrogen base and histidine than medium only ammonium sulfate and only yeast nitrogen base.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Manglallan, Eduardo P. "Water quality baseline study and non-point source pollution analysis on Waikele Stream, West Loch Estuary, Oahu, Hawaii." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/26334.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

TAKEDA, Kazuya, Takanori NISHINO, and Kenta NIWA. "Selective Listening Point Audio Based on Blind Signal Separation and Stereophonic Technology." Institute of Electronics, Information and Communication Engineers, 2009. http://hdl.handle.net/2237/15055.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Cziesch, Jarrett. "An Introduction to Identifying Nonpoint Sources of Water Pollution Using a Modified Land Use Conflict Analysis Identification Strategy (LUCIS) Model, Non-point Source Identification Strategy: NPSIS." The University of Arizona, 2015. http://hdl.handle.net/10150/576109.

Повний текст джерела

Анотація:

This paper examines the Non-Point Source Identification Strategy (NPSIS); a modification of the Land Use Conflict Identification Strategy (LUCIS): NPSIS is a raster model useful for identifying non-point sources of water pollution from three known contributors (agriculture, domestic, and natural background). By using a standard operating procedure, developers are able to create standardized datasets useful for identifying non-point sources of water pollution throughout the contiguous United States. The NPSIS model process requires the use of three “non-point source water pollution” contributors. A contributor is termed as a Non-Point Category (NPC) that contains collective elements (i.e. nutrient applications for agricultural purposes and urban runoff from highly developed areas). Using a survey, water resource professionals familiar with chosen study areas rank each NPC element according to potential impact to water quality. Following the survey, raster datasets that represent each NPC and impact to water quality are created using a lowest to highest (“1-9”) ordinal rank system derived from survey results after which each dataset is normalized using a (“1-3”) ordinal rank. Finally, the normalized NPC datasets are combined into one final model useful for identifying each dominant NPC by rank and location within a specified USGS watershed. In conclusion, the modifications to the LUCIS method yields results beneficial for identifying non-point source loads of water pollution.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Koo, Bonjin. "A study on the filtration efficiency of micro particle pollutants from non-point source : focused on road runoff and CSOs." Thesis, Nice, 2014. http://www.theses.fr/2014NICE4092/document.

Повний текст джерела

Анотація:

L’imperméabilisation des surfaces et l’augmentation des débits de pointe sont liés au développement croissant des environnements urbains. Avec cette croissance urbaine, les processus de ruissellement sont largement affectés et représentent un secteur dans lequel des actions doivent être entreprises afin d’assurer à la fois le développement économique et la protection de l’environnement et des ressources en eau. Le ruissellement est fréquemment associé à des pollutions diffuses (Non Point Source) qui ne sont généralement pas prises en compte dans les dispositifs classiques de régulation hydraulique. L’objectif de cette recherche était d’évaluer les performance de dispositifs de filtration sur les micro particules polluantes diffuses issues des chaussées routières et des déversoirs d’orages des réseaux d’assainissement unitaires (Combined Sewer Overflows – CSOs). Le protocole expérimental implique de mesurer, dans un premier temps, la taille et les caractéristiques des particules polluantes diffuses et ensuite, de réaliser une procédure identique à la sortie des installations de filtration et de traitement. Les modifications dans la distribution de la taille des particules et de leurs caractéristiques sont alors analysées. Les quatre principaux dispositifs de filtration disponibles - Expanded Polypropylene (EPP), Expanded polystyrene (EPS), Perlite pour les particules flottantes et Zeolite pour les non flottantes – ont été implanté sur un équipement de test et les résultats comparés. Une modélisation 3D (CFD) a été réalisée afin d’optimiser la conception de la disposition de filtration
The impermeable area and the peak discharge volume have been consistently increasing due to widening of city development and renewal. Thus, distortion of water cycle has been serious problem compared to the past. When it comes to NPS pollution, lack of information on the load and characteristics of pollutants led to the insufficient reduction measures. The purpose of this study is to investigate the effectiveness of filters to control micro particles from non-point sources, especially from road runoff and Combined Sewer Overflows (CSOs). The study first examined the particle size and characteristics of NPS pollutants, and then analyzed the head loss, treatment efficiency and changes in particle size distribution before and after the treatment using device type facilities. The four most commonly used filters - Expanded Polypropylene (EPP), Expanded polystyrene (EPS), and Perlite as floatability filtering materials, and Zeolite as non-floatability - were compared. The upward-type filtering equipment was manufactured for the lab experiment, and CFD modeling was conducted to identify optimized design parameters. The results showed that the ratio of micro particles(＜100 ㎛), to which the filtering process can be applied, was highest in samples from the road runoff, followed by one from the bridge, and from the parking lot. The results using road runoff displayed that EPP was most efficient with ratio of 89% to treat SS and COD

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Bradley, Xuan Qi. "Analysis of Non-point Sources and Natural Attenuation Effect in the Acid Mine Drainage Affected Black Fork Sub-watershed, Perry County, Ohio." Ohio University / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1038836721.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Nheili, Rafife. "How to improve the numerical reproducibility of hydrodynamics simulations : analysis and solutions for one open-source HPC software." Thesis, Perpignan, 2016. http://www.theses.fr/2016PERP0045/document.

Повний текст джерела

Анотація:

La non-reproductibilité numérique apparait dans divers domaines d'application de la simulation HPC. En effet, les différentes distributions d'un calcul parallèle peuvent mener à des résultats numériques différents, à cause des particularités de l'arithmétique flottante. Le besoin de reproductibilité numérique est motivé pour le débogage, le test et la validation des codes de calcul scientifique. Nous nous intéressons aux simulations par éléments finis en hydrodynamique implémentées dans le logiciel openTelemac qui est largement utilisé pour des applications industrielles et scientifiques. Nous identifions et analysons les sources de cette non-reproductibilité. Nous définissons et implementons comment récupérer la reproductibilité numérique de deux modules d'openTelemac. Nous mesurons que le sur-coût en terme de temps de calcul de la version reproductible est tout à fait raisonnable en pratique
HPC simulations in various scientific domains suffer from failures of numerical reproducibility because of floating-point arithmetic peculiarities. Different distributions of a parallel computation may yield different numerical results. Numerical reproducibility is a requested feature to facilitate the debug, the validation and the test of industrial or large software. In this thesis, we focus on the openTelemac software that implements finite element simulation for industrial and scientific hydrodynamics. We identify and analyze the sources of this reproducibility failure. We define and implement how to recover numerical reproducibility in two openTelemac modules. We also measure that the running time extra-cost of the reproducible version is reasonable enough in practice

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Miguel, Rodrigo Brenner. "Aplicação da análise inversa para determinar os parâmetros do modelo de múltiplas fontes ponderadas para estimar o fluxo de calor de uma chama do tipo jato laminar de metano-ar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/133131.

Повний текст джерела

Анотація:

A estimativa acurada do fluxo de calor radiativo na região próxima à chama do tipo jato não pré-misturada é necessária para garantir a segurança de pessoas e equipamentos em caso de vazamentos ou processo de descarte na indústria de petróleo e gás. A simulação computacional dos fenômenos físicos envolvidos na transferência de calor e combustão do processo tem alto custo computacional. No presente trabalho é apresentado um estudo para o emprego do modelo de múltiplas fontes ponderadas para a estimativa do fluxo de calor radiativo no campo próximo à chama. O modelo matemático simplificado tem baixo custo computacional e consiste em representar a transferência de calor radiativa por fontes pontuais distribuídas no eixo central da chama. Cada fonte tem um peso proporcional à contribuição de cada região discretizada da chama na transferência de calor por radiação. Para determinar o peso de cada fonte foi utilizada a análise inversa pelo método da Otimização Extrema Generalizada, no qual o fluxo de calor é dado de entrada enquanto o peso de cada fonte é dado de saída. Como dado de entrada foi utilizado o fluxo de calor radiativo medido experimentalmente de um conjunto de 12 chamas, com potência entre 0,139 e 0,554 kW. A análise inversa foi utilizada para recuperar os pesos, e a fração radiante, que geram o fluxo de calor radiativo com maior compatibilidade com os dados experimentais em três abordagens. A primeira abordagem consiste em aplicar a análise inversa em cada chama separadamente, e depois de obtidos os pesos correlaciona-los com a potência da chama. Na aplicação do método em cada chama individualmente, o desvio máximo do resultado do modelo com os dados experimentais é de 5%. Em uma segunda abordagem, foi utilizada a análise inversa para obter diretamente os coeficientes de uma função entre os pesos do modelo e a potência da chama e seu comprimento estimado, o desvio máximo encontrado é de 18,6%. Na terceira abordagem, a análise inversa foi utilizada novamente para encontrar os coeficientes da função que correlaciona a potência da chama com parâmetros do modelo, e neste caso foi utilizado o comprimento experimental da chama para posicionar as fontes pontuais. Para o caso em que sete fontes foram posicionadas a 2,25 vezes o comprimento da chama medido experimentalmente, o desvio máximo observado foi de 8,6% e o desvio médio de 2,9%.
The accurate approximation of radiative heat flux on non-premixed flame in the region adjacent to the flame is required to guarantee the staff and machinery safety on oil and gas industry in cases of fuel leaking or disposal process. The physical phenomena involved on heat transfer and combustion has high computational cost in numerical simulation, in accidental leaking cases it is prohibitive. In the present study it is presented an application of Weighted Multi-Point Sources model to predict the radiative heat flux in the region adjacent to the flame. The simplified mathematical model has low computational cost and simulates the radiative heat transfer by punctual sources placed at the flame axis. Each source has the weight proportional to heat transfer contribution by each flame portion. To set each source's weight, it was used the inverse analysis by the Generalized Extremal Optimization. In inverse analysis the radiative heat fluxes are the input data while the weight of each source is the sought variable. As input data are used the radiative heat fluxes measured from a set of 12 flames, with power between 0.139 and 0.554 kW. The inverse analysis was used to recover the weights, and the fraction of heat radiated, which generate radiative heat fluxes with greater compatibility with the experimental data on three approaches. The first approach is to apply the inverse analysis in each flame separately, obtain the weights and then correlates them with the flame power. In method application for each flame, the maximum deviation between model outcome and experimental data was less than 5%. In a second approach, it was used the inverse analysis to directly obtain the coefficients of a function between the model's parameters and the flame’s power. When used just the flame power as model input parameter to distributes the sources and predict the heat flux, the maximum deviation is 18.6%. In the third approach, the inverse analysis was again used to find the coefficients of the function which correlates the flame power with model parameters, in this case was used the experimental flame length for positioning the point sources. For the case in which seven sources are positioned at 2.25 times the experimental length of the flame, the maximum deviation observed was 8.6% and the mean deviation of 2 9%.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Gonzalez, Ander. "Integration of photovoltaic sources and battery based storage systems – A DC analysis and distributed maximum power point tracking solution." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/282059/4/TOC_vf.pdf.

Повний текст джерела

Анотація:

In this thesis the integration of photovolatic (PV) generation and energy storage into the electrical grid is discussed. Although the studied system is for grid tied applications, here the integration of the PV generation and the energy storage system (ESS) on the DC-side of the system is addressed. The work contained in this thesis focuses on the integration of the DC-working parts before interfacing them with the grid through the use of an inverter and seeks an increasing in the energy that the system can deliver.First, a study of classical systems that present well-differentiated parts is presented: PV generation, a lithium-ion battery based ESS, the utility grid and a residential electricity consumer. PV installations of 3 and 10kWp are considered together with storage capacities ranging from 1 to 9kWh. This yields interesting insights on how the system works based on the timing of the generation and consumption of energy. The results are used to highlight the weaknesses of the selected converter arrangement for the interfacing of the PV source and the ESS. Results show that the system is rather stiff and lacks from conversion efficiency when it needs to work in a wide range of powers, mainly due to low consumer power demand during battery discharge. In this first part of the thesis, three solutions to workaround the efficiency problem are proposed: reducing the difference between the ESS and the DC-bus voltages, using isolated converters to interface the ESS, or adopting a new arrangement of the parts of the system. One of the first two proposed solutions should be adopted if the same system topology is to be kept. These two solutions address the efficiency problem when the ESS is involved in the energy conversion. The third solution is proposed as alternative to the classical systems that use a DC-bus to exchange power with the different parts of the system. The new proposed arrangement features a distributed maximum power point (DMPPT) type system that includes storage at module level. DMPPT systems are able to track the maximum power point (MPPT) of each panel separately by connecting a small power electronic converter (PEC) to each PV panel. They are specially useful when the PV installation receives uneven irradiance, i.e. shadows are present in some of the panels, increasing the annual yield of PV energy from 7 to 30% as reported in the literature. Unfortunately, this kind of systems cannot always handle high irradiance mismatches, and fail to track the maximum power point (MPP) throughout the whole installation in some cases. Including batteries at module level instead of connecting them to the DC-bus, allows for increasing the MPPT range of the system, virtually to any severity of irradiance mismatch (depending on the state of charge (SoC) of the battery pack), as well as adding storage capability to the system. The novel proposed system is able to workaround the problems of using non-isolated converters, achieving PV energy conversion efficiencies from 86% (for at least 10% of the peak power) to 90% and storage charge/discharge efficiencies ranging from 86% to 95%. Besides, it brings the opportunity to exploit the synergies of having storage at module level in systems that combine renewable energies and storage. Moreover, DMPPT systems achieve superior PV generation under partially shaded conditions when compared to classical PV arrays increasing the PV generation when compared to classical or centralized PV installations up to 45% in power as reported in the literature.In the second part of the thesis, the proposed novel DMPPT topology is presented. The whole system is fully designed from scratch, including PECs, sizing of the different parts of the modules, embedded control loops of the modules and supervisory control of the whole system. Finally, the results obtained from running the proposed system are shown and discussed, and suggestions given on how to operate and protect the system. Experimental results are obtained using a 1.5kWp PV power and 1.5kWh capacity test bench built for that purpose.The proposed system is able to generate PV energy, store the energy coming from PV generation and inject the generated and stored energy into the grid. The proposed system extends the MPPT capability of storage-less series-connected DMPPT systems. This is achieved by using the batteries not only to store energy when required, but also to compensate the power mismatch across DMPPT modules of the same string when the output voltage of the modules becomes a limit. It also presents a modular and upgradable approach to PV systems including storage. This modularity also brings fault tolerance, and an ability to continue working after failure of one or more of the DMPPT modules by partially or completely isolating the faulty module (depending on the nature of the fault). Moreover, the addition of the DC-DC converters allows for the use of different PV panels in the system, i.e. from different manufacturers or technologies.In conclusion, the presented system is very flexible, can be designed for a wide range of power levels and energy storage sizes, and presents improved reliability when compared to other series-connected DMPPT systems.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Thomason, Krista A. "Trends Analysis and a Yearly Comparison of Point Sources of Atmospheric Mercury Using HYSPLIT Back Trajectories Focused in Athens, Ohio." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1557161272706908.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Speir, Cameron Lindsey. "Two Cost Analyses in Resource Economics: The Public Service Costs of Alternative Land Settlement Patterns and Effluent Allowance Trading in Long Island Sound." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31154.

Повний текст джерела

Анотація:

This study offers two cost analyses to inform public policy decisions on the use of land and water resources. The first presents some public service costs associated with different spatial forms of land development. The second cost analysis presents costs associated with three different policy options for meeting water quality goals in Long Island Sound.

The objective the first analysis is to determine the cost to local governments of providing water distribution and wastewater collection services to alternative spatial forms of residential development. Components of spatial form are explicitly defined in terms of lot size, distance and tract dispersion. An engineering cost model is used to determine the water and sewer costs to three sets of hypothetical land settlement scenarios. Each set shows the effect of one component of spatial form on cost.

The results show that smaller lots, shorter distances between existing centers and less tract dispersion reduce public water and sewer costs. Lot size is found to have the most pronounced effect on water and sewer cost. Some policy options for reducing the public service costs associated with development are considered.

The objective of the second cost analysis is to analyze the cost implications of a nitrogen allowance trading system for wastewater treatment plants in Connecticut. Effluent allowance trading involves the transfer of pollution control responsibility between pollution sources. Effluent allowances are the right to discharge a given quantity of waste into the environment over a given time period. Allowance trading has been proposed as a way of reducing pollution control costs, encouraging innovative pollution prevention techniques and more quickly achieving water quality goals.

Long Island Sound, a major estuary in the northeastern United States, experiences chronically low dissolved oxygen levels. Excessive nitrogen loads from anthropogenic activities in the Sound watershed have been identified as the cause of the oxygen problem. The state of Connecticut is examining the possibility of introducing an effluent allowance trading system in order to reduce the cost of achieving required reductions in nitrogen discharge. A linear programming model is used to predict trading outcomes and allowance prices. The total cost of achieving a nitrogen load cap is calculated under three administrative approaches. The first approach is a uniform reduction requirement where all plants are required to reduce discharge by the same proportion. The second approach is an administrative reallocation of waste load where a regulatory agency assigns control responsibility based on the agency's understanding of relative costs. The third approach is a flexible effluent allowance trading system. The results will show that a trading program offers cost savings over traditional regulatory approaches, demonstrate the potential for further cost savings from pollution prevention activities and estimate the cost savings that would result from including nonpoint sources in the overall nitrogen reduction strategy.
Master of Science

Стилі APA, Harvard, Vancouver, ISO та ін.

16

van, der Kamp Jonathan [Verfasser]. "Social cost-benefit analysis of air pollution control measures - Advancing environmental-economic assessment methods to evaluate industrial point emission sources / Jonathan van der Kamp." Karlsruhe : KIT Scientific Publishing, 2017. http://www.ksp.kit.edu.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Khiari, Souad. "Problèmes inverses de points sources dans les modèles de transport dispersif de contaminants : identifiabilité et observabilité." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2301.

Повний текст джерела

Анотація:

La recherche et les questions abordées dans cette thèse sont de type inverse : la reconstitution d'une source ponctuelle ou la complétion d'une donnée à la limite inconnue à l'extrémité du domaine dans les modèles paraboliques de transport de contaminants. La modélisation mathématique des problèmes de pollution des eaux fait intervenir deux traceurs, l'oxygène dissous (OD) et la demande biochimique en oxygène (DBO) qui est la quantité d'oxygène nécessaire à la biodégradation de la matière organique. En effet, au cours des procédés d'autoépuration, certaines bactéries aérobies jouent un rôle principal. Ces micro-organismes décomposent les matières organiques polluantes en utilisant l'oxygène dissous dans le milieu. Afin de compenser ces données manquantes, les champs, solutions du problème, sont observés directement ou indirectement. Les problèmes inverses qui en résultent sont quasi certainement mal-posés voire même sévèrement mal-posés pour la plupart. Dans cette thèse, nous proposons justement une analyse aussi poussée que possible sur la question de l'identifiabilité pour les deux problèmes inverses décrits ci-dessus. Nous avons démontré un résultat d'unicité pour des sources fixes dans le cas d'observations décalées. La réalité pour l'observation est nuancée et l'idéal n'est pas acquis ; des mesures directes sur la DBO sont difficiles à obtenir. En revanche collecter des données sur l'OD est possible en temps réel et avec un faible coût. La DBO est donc observée de façon indirecte, grâce au couplage dans le système de Streeter et Phelps, l'information passe de l'OD à la DBO. Pour ce problème aussi, nous avons produit un résultat d'unicité pour la reconstruction de la source ou puits ponctuel qui serait présent dans l'équation de transport sur l'OD. Nous avons ensuite examiné des questions annexes à l'identifiabilité telles que le degré d'instabilité des équations à résoudre. De ce type d'informations dépendent le comportement des méthodes numériques et des algorithmes de calcul à utiliser
The research and the questions approached on this thesis are inverse type : the reconstruction of point-wise source or the data completion problem in parabolic models of transport of contaminants. The mathematical modelling of the problems of water pollution includes two tracers, the dissolved oxygen (DO) and the biochemical demand in oxygen (BDO) which is the quantity of oxygen necessary for the biodegradation of organic matter. Indeed, during the biodegradation process, aerobic bacteria play a leading part. These micro-organisms decompose polluting organic matters by using the dissolved oxygen in the middle. To compensate these missing data, fields, solutions of the problem, are observed directly or indirectly. The resulting inverse problems are ill-posed. Their mathematical study rises big complications and their numerical treatment isn't easy. We demonstrated a uniqueness result for fixed sources in the case of moved observations. The reality for the observation is qualified and the ideal is not acquired; direct measures on the BOD are difficult to obtain. On the Other hand to collect data on the DO is possible in real time With a moderate cost. The BOD is thus observed in indirect way, thanks to the coupling in the system of Streeter and Phelps, the information passes from the DO to the BOD. For this problem, we produced a uniqueness result for the reconstruction of source. Then, we examined the degree of instability of the equation to be solved. The behaviour of numerical methods depend on this type of information

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Punase, Shubha. "Utilizing Multiple Data Sources In The Preparation Of A Vision Zero Plan For The City Of Alexandria: Investigating The Relationship Between Transportation Infrastructure, Socio- Economic Characteristics, And Crash Outcomes In The City." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/78329.

Повний текст джерела

Анотація:

“Vision Zero,” first adopted by Sweden in 1997, is a road safety policy that aims to achieve a transportation system having zero fatalities or serious injuries for all modes of transportation. It takes a proactive approach to road safety system by identifying risk and taking steps to prevent injuries. Historically, traffic related crashes have disproportionately impacted vulnerable communities and system users including people of color, low income individuals, seniors, children, and pedestrians, bicyclists, and transit users (who typically walk to and from public transport). These inequities are addressed in the Vision Zero framework by prioritizing interventions in areas that need safety improvements the most. In 2016, the Alexandria City Council voted unanimously to develop a “Vision Zero” policy and program as a part of its updated transportation master plan. It required an initial equity analysis to assess the impact of traffic crashes on the traditionally underserved communities / groups (groups from at least one of these categories: low-income; minority; elderly; children; limited English proficiency; persons with disabilities; and/or pedestrians/ bicyclists/ transit users). This study combines three different methods to investigate the equity issues regarding traffic safety: 1) descriptive analysis of the spatial pattern of crashes and their relationship with the demographic profiles of neighborhoods at census block group level (for 2010-2014 period); 2) descriptive analysis of the crash trends in Alexandria; and 3) exploratory regression analyses for two different units of analysis (an aggregate regression analysis of crashes at census block group, and a disaggregate regression analysis of the individual level crash reports of traffic crashes). The analysis found that the elderly, school aged children, rail/subway users, and pedestrians had a higher risk of fatalities and severe injuries in traffic crashes. Higher job densities, alcohol impairment, and speeding were significantly related to higher KSI, whereas, smaller block sizes (higher number of street segments per sq. mile area of census block group), higher housing density, and use of safety equipment were related to lower KSI.
Master of Urban and Regional Planning
“Vision Zero,” first adopted by Sweden in 1997, is a road safety policy that aims to achieve a transportation system having zero fatalities or serious injuries for all modes of transportation. It takes a proactive approach to road safety system by identifying risk and taking steps to prevent injuries. Historically, traffic related crashes have disproportionately impacted vulnerable communities and system users including people of color, low income individuals, seniors, children, and pedestrians, bicyclists, and transit users (who typically walk to and from public transport). These inequities are addressed in the Vision Zero framework by prioritizing interventions in areas that need safety improvements the most. In 2016, the Alexandria City Council voted unanimously to develop a “Vision Zero” policy and program as a part of its updated transportation master plan. It required an initial equity analysis to assess the impact of traffic crashes on the traditionally underserved communities / groups (groups from at least one of these categories: low-income; minority; elderly; children; limited English proficiency; persons with disabilities; and/or pedestrians/ bicyclists/ transit users). This study combines three different methods to investigate the equity issues regarding traffic safety: 1) descriptive analysis of the spatial pattern of crashes and their relationship with the demographic profiles of neighborhoods at census block group level (for 2010-2014 period); 2) descriptive analysis of the crash trends in Alexandria; and 3) exploratory regression analyses for two different units of analysis (an aggregate regression analysis of crashes at census block group, and a disaggregate regression analysis of the individual level crash reports of traffic crashes). The analysis found that the elderly, school aged children, rail/subway users, and pedestrians had a higher risk of fatalities and severe injuries in traffic crashes. Higher job densities, alcohol impairment, and speeding were significantly related to higher KSI, whereas, smaller block sizes (higher number of street segments per sq. mile area of census block group), higher housing density, and use of safety equipment were related to lower KSI.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Gratecap, Jean-Baptiste. "Agriculture biologique et qualité des eaux dans des aires d’alimentation de captage : diversité des postures techniques d’agriculteurs conventionnels et biologiques et pressions nitrate et pesticide induites." Thesis, Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0059/document.

Повний текст джерела

Анотація:

Face à la pollution généralisée des masses d’eau souterraines par les nitrates et les pesticides, l’agriculture biologique (AB) est présentée comme un outil pertinent pour la reconquête de la qualité des eaux sur les aires d’alimentation de captage (AAC). Ce travail vise à mieux définir l’opportunité d’un développement de l’AB sur des zones à enjeu eau. L’objectif de la thèse est d’évaluer conjointement la faisabilité des conversions sur les exploitations de l’AAC et l’efficacité de ces conversions par rapport aux enjeux de reconquête de la qualité de l’eau.Etudier l’opportunité d’un développement de l’AB à l’échelle territoriale suppose d’instruire la diversité des exploitations et des profils d’agriculteurs sur la zone à enjeu eau. Pour être en mesure de tester l’opportunité des conversions, une méthode typologique permettant d’analyser conjointement la variabilité actuelle des pressions sur les zones à enjeu eau et la propension des agriculteurs conventionnels à la conversion est nécessaire.Pour produire cette typologie, nous avons développé une méthode innovante d’analyse compréhensive des pratiques, centrée sur les principes d’action à l’origine des systèmes de culture. Les principes d’action correspondent à des méta-raisonnements à l’origine de l’organisation concrète des pratiques agricoles sur le territoire d’exploitation. Par l’analyse conjointe du discours des agriculteurs et de la variabilité des règles de décision, nous avons élaboré des typologies basées sur les postures techniques des agriculteurs pour i) identifier des principes d’action associés aux pratiques à risque et ii) dégager des proximités éventuelles entre agriculteurs biologiques et agriculteurs conventionnels. La méthode a été testée sur deux territoires à enjeu eau en Rhône-Alpes, sur lesquels des entretiens semi-directifs ont été réalisés auprès d’exploitants conventionnels et biologiques.Cinq principes d’action génériques à l’origine de l’organisation de l’assolement et cinq principes d’action génériques à l’origine des pratiques culturales ont été dégagés. A partir des différents principes d’action, des typologies des postures techniques ont été produites sur les deux terrains. Les pressions à l’origine de la lixiviation des nitrates et des pesticides ont été évaluées et spatialisées via le recours à des indicateurs agro-environnementaux. Nous avons démontré que la variabilité forte des indicateurs et leur distribution spatiale sur les AAC étaient liées à la diversité des postures techniques entre agriculteurs.Nous avons comparé les principes d’action mobilisés par les agriculteurs conventionnels et les agriculteurs biologiques « références » présents sur les zones à enjeu eau. Par l’étude des spécificités des postures techniques en AB, trois critères de propension à la conversion ont été identifiés. Plusieurs degrés de propension à la conversion ont été dégagés parmi les agriculteurs conventionnels des deux territoires.L’analyse croisée des degrés de propension à la conversion et des différentiels de pressions entre systèmes conventionnels et biologiques nous a permis d’évaluer l’opportunité d’un développement de l’AB sur les deux territoires. Nos résultats ont mis en évidence des niveaux de pression limités quant à la lixiviation des nitrates sur les systèmes biologiques : un développement exhaustif de l’AB à l’échelle des deux AAC entrainerait potentiellement une réduction forte de la lixiviation des nitrates. Néanmoins, l’opportunité d’un tel développement doit être relativisée. Les agriculteurs présentant une propension réelle ou forte à la conversion sont minoritaires sur les AAC. Ensuite, le différentiel des pressions entre systèmes conventionnels et systèmes biologiques diminue à mesure que la propension à la conversion augmente. Pour envisager une diminution forte des pressions sur les zones à enjeu eau, la conversion devrait concerner des exploitants pour lesquels cette conversion est difficilement envisageable à moyen terme
Many problems with nitrate and pesticide contamination from agriculture exist in European drinking water catchments. In France, a new mitigation approach aims at preventing water quality degradation in explicitly targeting agricultural non-point source pollutions associated with leaching of nitrates and pesticides. This work aims at assessing the opportunity to develop organic farming in water catchment areas in order to reduce nitrate and pesticide leaching from root zone. The objective was to analyze both i) feasibility of conversions to organic farming on farms concerned by water preservation and ii) the potential impacts of these conversions in terms of nitrate and pesticide leaching reduction.To explore the potential contribution of organic farming in water catchment areas, we develop an innovative typology approach to characterize farmers’ conceptions and strategies related to cropping systems’ organization on the farm territory. Our method was tested in two French water catchment areas characterized by diversified production systems, where semi-structured interviews were carried out with conventional and organic farmers. Resulting typologies of farmers were used to assess leaching risks variability related with current cropping systems and to identify potential similarities between conventional and organic farmers’ conceptions. Nitrate and pesticide leaching risks for cropping systems were assessed and spatialized by using four agro-environmental indicators. Our results show major variations for all indicators at both study sites, for example N-surpluses which range from -105 to 192 kg N ha-1 year-1. These variations are deeply related with diversity of farmers’ conceptions summarized in typologies. To assess proximity of conventional farmers to organic farming, we used typologies to compare conceptions related to organization of cropping systems between conventional and organic farmers. By analyzing specificities of organic farmers’ conceptions, we determined three main criteria of proximity to organic farming; these criteria were then used to identify various degrees of proximity to organic farming among conventional farmers in the catchment areas.To assess potential contribution of organic farming to water preservation in catchment areas, we firstly compared nitrate leaching risks between conventional and organic cropping systems. Our results reveal low leaching risks from organic systems, characterized by reduced N-surpluses and lower bare soils frequencies in autumn. According to these results, massive development of organic farming should decrease nitrate leaching in our two water catchment areas. However, analysis of similarities between conventional and organic farmers’ conceptions shows that a majority of farmers are characterized by a low level of proximity to organic farming. Moreover, the farmers who show strongest similarities with organic farmers’ conceptions are already those with low leaching risks cropping systems. To significantly lower nitrate leaching risks, conversions should concern conventional farmers with low degree of proximity to organic farming

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Ayvazyan, Vigen. "Etude de champs de température séparables avec une double décomposition en valeurs singulières : quelques applications à la caractérisation des propriétés thermophysiques des matérieux et au contrôle non destructif." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14671/document.

Повний текст джерела

Анотація:

La thermographie infrarouge est une méthode largement employée pour la caractérisation des propriétés thermophysiques des matériaux. L’avènement des diodes laser pratiques, peu onéreuses et aux multiples caractéristiques, étendent les possibilités métrologiques des caméras infrarouges et mettent à disposition un ensemble de nouveaux outils puissants pour la caractérisation thermique et le contrôle non desturctif. Cependant, un lot de nouvelles difficultés doit être surmonté, comme le traitement d’une grande quantité de données bruitées et la faible sensibilité de ces données aux paramètres recherchés. Cela oblige de revisiter les méthodes de traitement du signal existantes, d’adopter de nouveaux outils mathématiques sophistiqués pour la compression de données et le traitement d’informations pertinentes. Les nouvelles stratégies consistent à utiliser des transformations orthogonales du signal comme outils de compression préalable de données, de réduction et maîtrise du bruit de mesure. L’analyse de sensibilité, basée sur l’étude locale des corrélations entre les dérivées partielles du signal expérimental, complète ces nouvelles approches. L'analogie avec la théorie dans l'espace de Fourier a permis d'apporter de nouveaux éléments de réponse pour mieux cerner la «physique» des approches modales.La réponse au point source impulsionnel a été revisitée de manière numérique et expérimentale. En utilisant la séparabilité des champs de température nous avons proposé une nouvelle méthode d'inversion basée sur une double décomposition en valeurs singulières du signal expérimental. Cette méthode par rapport aux précédentes, permet de tenir compte de la diffusion bi ou tridimensionnelle et offre ainsi une meilleure exploitation du contenu spatial des images infrarouges. Des exemples numériques et expérimentaux nous ont permis de valider dans une première approche cette nouvelle méthode d'estimation pour la caractérisation de diffusivités thermiques longitudinales. Des applications dans le domaine du contrôle non destructif des matériaux sont également proposées. Une ancienne problématique qui consiste à retrouver les champs de température initiaux à partir de données bruitées a été abordée sous un nouveau jour. La nécessité de connaitre les diffusivités thermiques du matériau orthotrope et la prise en compte des transferts souvent tridimensionnels sont complexes à gérer. L'application de la double décomposition en valeurs singulières a permis d'obtenir des résultats intéressants compte tenu de la simplicité de la méthode. En effet, les méthodes modales sont basées sur des approches statistiques de traitement d'une grande quantité de données, censément plus robustes quant au bruit de mesure, comme cela a pu être observé
Infrared thermography is a widely used method for characterization of thermophysical properties of materials. The advent of the laser diodes, which are handy, inexpensive, with a broad spectrum of characteristics, extend metrological possibilities of infrared cameras and provide a combination of new powerful tools for thermal characterization and non destructive evaluation. However, this new dynamic has also brought numerous difficulties that must be overcome, such as high volume noisy data processing and low sensitivity to estimated parameters of such data. This requires revisiting the existing methods of signal processing, adopting new sophisticated mathematical tools for data compression and processing of relevant information.New strategies consist in using orthogonal transforms of the signal as a prior data compression tools, which allow noise reduction and control over it. Correlation analysis, based on the local cerrelation study between partial derivatives of the experimental signal, completes these new strategies. A theoretical analogy in Fourier space has been performed in order to better understand the «physical» meaning of modal approaches.The response to the instantaneous point source of heat, has been revisited both numerically and experimentally. By using separable temperature fields, a new inversion technique based on a double singular value decomposition of experimental signal has been introduced. In comparison with previous methods, it takes into account two or three-dimensional heat diffusion and therefore offers a better exploitation of the spatial content of infrared images. Numerical and experimental examples have allowed us to validate in the first approach our new estimation method of longitudinal thermal diffusivities. Non destructive testing applications based on the new technique have also been introduced.An old issue, which consists in determining the initial temperature field from noisy data, has been approached in a new light. The necessity to know the thermal diffusivities of an orthotropic medium and the need to take into account often three-dimensional heat transfer, are complicated issues. The implementation of the double singular value decomposition allowed us to achieve interesting results according to its ease of use. Indeed, modal approaches are statistical methods based on high volume data processing, supposedly robust as to the measurement noise

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Anastassiou, Michel. "Influence des conditions de soudage sur les contraintes residuelles dans un point soude par resistance sur toles minces d'acier a bas carbone : relation avec la tenue en fatigue." Paris, ENSAM, 1987. http://www.theses.fr/1987ENAM0012.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Perakis, Nikolaos. "Separation et detection selective des composes soufres dans les fractions lourdes des petroles : geochimie des benzo (b) thiophenes." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13093.

Повний текст джерела

Анотація:

Analyse et dosage des composes soufres presents dans une coupe lourde du petrole aramco 90 par chromatographie gazeuse avec detection soit par photometrie de flamme soit par spectrometrie de masse haute resolution. Etude comparative des methodes d'analyse. Etude des composes soufres dans des echantillons de petrole de rozel point et de schiste bitumineux de timahdit grace a l'identification par synthese de nouvelles familles d'alkylbenzo (b) thiophenes

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Fujdiak, Radek. "Analýza a optimalizace datové komunikace pro telemetrické systémy v energetice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-358408.

Повний текст джерела

Анотація:

Telemetry system, Optimisation, Sensoric networks, Smart Grid, Internet of Things, Sensors, Information security, Cryptography, Cryptography algorithms, Cryptosystem, Confidentiality, Integrity, Authentication, Data freshness, Non-Repudiation.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Leung, Ming-Kei, and 梁銘基. "First flush analysis of agricultural non-point source." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/46935419760533270469.

Повний текст джерела

Анотація:

碩士
國立成功大學
環境工程學系碩博士班
96
Stormwater runoff was monitored on 6 separate agricultural watersheds, which were chosen to represent distinct types of farming and spreading chicken fields, along with various watershed characteristics. A total of 57 storm events were monitored to investigate the first flush phenomenon. There are two first flush phenomenon definition, one is concentration first flush(CFF), another is mass first flush(MFF). CFF may be defined as the initial period of stormwater runoff during which the concentration of pollutants is substantially higher than during later stages. MFF may be defined as the initial period of stormwater runoff during which the quality of pollutants throughout the majority of the pollution load. The magnitude of the first flush phenomenon was calculated using a method of data analysis which results in determining the dynamics event mean concentration ratio(REMC) and mass first flush ratio(MFFn). In addition, statistical and graphical correlation analysis of the REMC and MFFn with storm characteristics and environmental factors was made to determine if the first flush is related to site or storm characteristics. As the results, although the percentage of impervious area near zero, we can still be found strength to moderate concentration first flush phenomenon and moderate to mild mass first flush phenomenon in agricultural area. The results and analyses performed also indicates that the concentration first flush phenomenon of SS,COD and TP correlate well with total rainfall, total runoff and rain time but there are no correlation between the mass first flush phenomenon. No correlation was observed between the first flush phenomenon and area, slope and porosity. In this study, through cluster analysis proved that the first flush phenomenon in agricultural areas occurred mainly on non-soluble pollutants.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Hong, Hong-Jyh, and 洪轟誌. "Parameter Uncertainty Analysis for a Grid-Based Non-Point Source Pollution Model." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/61159924289200892288.

Повний текст джерела

Анотація:

碩士
國立交通大學
環境工程研究所
82
Non-point source pollution control(NPSPC) for reservoir has become a major environmental protection mission in Taiwan, ROC. Mathematical models are applied for evaluation of NPSPC related tasks. Model parameter uncertainty, however, introduces significant effect on modeling results and thus the decision made on the basis of these results may not be appropriate. This research was therefore initiated for analyzing the parameter uncertainty for exploring an improved modeling procedure. Drainage pattern generated from DEM data and rainfall intensity were the two parameters studied for their uncertainties in this research. A program was developed to resolve conflicting directions in a DEM generated drainage pattern for use by a grid based nonpoint source pollution model, AGNPS. Auto-MOUSE, a Monte-Carlo analysis package, was integrated with AGNPS for assessing the rainfall uncertainty. A case study for the watershed of the Po-San off-channel reservoir in Hsinchu County was implemented. Significant spatial variation of pollution distribution simulated by using different drainage pattern generating methods was observed. The effect of rainfall randomness on seasonal and spatial loading distribution was assessed and computed based on a Monte- Carlo simulation. Graphical presentations of research results and spatial data analysis were implemented by a geographical information system, Grass. It is expected that the quality of decision making can be effectively improved with the proposed parameter uncertainty analysis procedure.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Fu, Jenn-Hsin, and 傅振鑫. "Analysis and Experimental Study of The Characteristics of The Point Sound Source Image." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/37662353139024339920.

Повний текст джерела

Анотація:

碩士
逢甲大學
機械工程學系
87
The sound-sources image display technique is one of the recently proposed blend guide techniques. It has serious problems of both poor resolution and difficulty in implementation. For overcome those drawbacks, the technique of sound virtual reality is considered. One of the know how of applying the technique of sound virtual reality to sound-sources image display technique is the most suitable frequency for sound-sources image display implementation, and analyze the directional sensitivity of human ears to point sound source locations in 3-D space. This paper concludes the experimental results of the most suitable frequency and the location sensitivity. The most suitable frequency is the frequency that both is clearly to human hearing and makes the maximum difference in voltage measured at both ears. This study conducts experiments to determine this frequency first, then adopts this frequency for sound-sources image display implementation to determine the directional sensi-tivity of human ears to point sound source locations in 3-D space. For the experimental of location sensitivity determination, this study adopts the center of human head as the origin of the 3-D coordinates, and put the point-sound-source locations around the hemi-sphere surface to analyze the frequency response of the human ears and determine the location sensitivity.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Yuan, Kuo Lei, and 郭力源. "Thermoelastic analysis of an infinite curvilinear cracked plate th a point heat source." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/68303739182563101227.

Повний текст джерела

Анотація:

碩士
國立臺灣科技大學
工程技術研究所
81
Boundary value problems for circular-arc crack embedded in the homogeneous material or dissimilar materials under the appli -cation of a point heat source are formulated and solved in clos -ed form. Based on the Hilbert problem formulation and a special technique of contour integration, exact solutions of the tempera -ture field and stress field are obtained in an explicit form. It is found that the temperature gradient or thermal stresses near the tips of a curved crack always possess the characteristic inverse square-root singularity in terms of the radial distence away from the crack tip under the application of heat source. Due to this singular behavior, the heat flux intensity factor is intr -oduced to measure the thermal energy intensification cumulated in the vicinity of the crack tip. Numerical results for the temp -erature and heat flux intensity factor are provided in graphic form. The simultaneous existence of Mode-I and Mode-II stress int -ensity factors are provided in the present study. It is shown that the thermal system having a smaller crack length would make the heat flux intensity factor lower. Both the Mode-I and Mode-II stress intensity factors for homogeneous material are found to depend on the strength of heat source, heat conductivity as well as thermal and elastic properties. The non-negative Mode-I stress intensity factor is found to present in this paper for the applic -ation of the heat sink which validates the fully open cracksumption.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Burley, Ryan Thomas. "Application of Importance Sampling for Point Source Analysis with the IceCube Neutrino Observatory." Thesis, 2020. http://hdl.handle.net/2440/124928.

Повний текст джерела

Анотація:

The IceCube Neutrino Observatory observes astrophysical neutrinos produced by the most energetic processes in the Universe. To date, the exact sources of these neutrinos, particles with no electric charge and almost negligible mass, are still a mystery. In an attempt to identify the sources of the highest energy neutrinos, the IceCube Collaboration uses likelihood analysis to search for clustering of neutrino events in the sky. An important part of this analysis is knowing how often neutrinos randomly cluster on the sky to replicate what an astrophysical neutrino source would look like. However, numerous simulations are required to properly understand this, and hence so are excessive computational resources. In this thesis, importance sampling is used to force rare clusters of neutrinos to occur on simulated skies. Two methods of importance sampling have been created to force these clusters to occur, a Gaussian weighting method and a binomial weighting method. Once these events are clustered, an appropriate weight can be applied to the sky the cluster is created on, and a likelihood analysis can be performed. We demonstrate how these methods can be used to identify the frequency at which rare clusterings of neutrinos occur, without the requirement of exhaustive computational time. We find that these rare clusters can be forced to occur on a sky with importance sampling, as can appropriate weights indicating the frequency the cluster would appear at a fixed point in space. However, further investigation is required to understand how to correctly apply sampling weights to the results when we perform the likelihood analysis over a full sky. The result of using importance sampling to identify rare clusters of neutrinos is used to investigate the effectiveness of a new test statistic for hypothesis testing in point source analysis. The most powerful test statistic for this analysis is the maximum likelihood, ℒ.̂ This is obtained by maximising a likelihood function relative to the maximum number of signal events, 𝑛̂𝑠, from some position on the sky. We construct a new statistic using a combination of the ℒ̂ and 𝑛̂𝑠 values, which has been suggested to be a more powerful test statistic than ℒ̂on its own. Using distributions obtained with importance sampling, we find that there is no evidence to indicate that a test statistic constructed using ℒ̂and 𝑛̂𝑠 is more powerful than ℒ̂on its own. Furthermore, we find that it simply replicates the results of ℒ̂by itself, due to the strong correlation between the ℒ̂and 𝑛̂𝑠 combinations in the null and alternate hypotheses tested.
Thesis (MPhil) -- University of Adelaide, School of Physical Sciences, 2020

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Chen, Shi Zhong, and 陳世忠. "Thermal stress analysis of crack problems in bonded dissimilar media with a point heat source." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/94508862869652294302.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Wang, Jian Wen, and 王建文. "Thermal stress analysis of the half-plane crack problem under a point heat source on its surface." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/56787530011515082672.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

ZHENG, YU-XIANG, and 鄭宇翔. "Three-level Neutral Point Clamped (NPC) Rectifier Using DC-Bus Voltage Ripple Analysis under Unbalanced Grid Source." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7933z5.

Повний текст джерела

Анотація:

碩士
國立臺灣科技大學
電機工程系
107
This thesis proposes a control strategy for a three-level diode clamped ac/dc converter to achieve balanced line current under unbalanced ac source. Consequently, through the control scheme proposed, in this paper, it can not only balance input current but also reduce dc output voltage ripple when three-phase neutral-point clamped rectifier works on input voltage unbalance condition. The proposed strategy is based on the ripple characteristics in the dc filter capacitors deployed in the dc output. The ac ripples contained in the dc voltages of the filter capacitors are highly affected by the balanced condition of the ac source. Under ideally ac source, only sixth harmonics will exixt, while second and third harmonics will emerge under unbalanced ac source. The latter two harmonics will change the ripple waveforms dramatically and then makes power quality deterioration. These multi-harmonic ripple waveforms can be used to compensate the unbalanced line current caused by unbalanced ac source, and no need to use coordinate transformation, positive and negative phase sequence disconnecting method, direct power control that calculations and analysis can control the current imbalance. The converter dc output voltage is regulated by the coltroller with unity power factor. The ripple waveforms are trsansfered to pulse type, form which the pulse wides are used to estimate the unbalanced condition of the ac sourcecontrol system and then control scheme is planned to control device to generate the compensated comment of line cueernt, at last, through current control loop control three-phase input current, using pulse width modulation generate switch signal, so it can improve and modulate input ac current unbalance factor. The control scheme of this thesis using Matlab/Simulink simulation system to evaluate the performance of the proposed scheme. Moreover, the a 750VDC/2kW, PF 0.99 three-phase NPC rectifier prototype based on digital signal processor TMS320F28069 also is established to demonstrate the vadility of the proposed system. Both simulation and experimental results show the correctness and practicality of proposed control scheme.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Fitzgerald, Garrett Christopher. "Multi-scale Analysis of Methane Gas Hydrate Formation and Dissociation via Point Source Thermal Stimulation and Carbon Dioxide Exchange." Thesis, 2014. https://doi.org/10.7916/D8VQ30M7.

Повний текст джерела

Анотація:

The formation and dissociation of methane gas hydrate was investigated over a range of laboratory scale systems with sample volumes of 1.3 cm3, 0.059 m3 and 0.141 m3. Three unique hydrate apparatuses were used to study a point source thermal dissociation method in which gas production profiles and cumulative efficiencies were found to be dependent on the initial hydrate saturation and the degree of thermal stimulation. Hydrate growth was observed to develop in a non-homogeneous manner with hydrate distribution displaying strong apparatus specific behavior. Heterogeneous hydrate distribution contributed to the production efficiencies of point source thermal stimulation and is an essential parameter when evaluating a gas hydrate reservoir. Thermal stimulation was applied to sediments with initial pore space hydrate saturations ranging from 10% to 80% producing maximum cumulative thermal production efficiencies ranging from 57% to 90%. Production performance was improved with higher initial hydrate saturation; increasing the initial hydrate saturation from 20% to 35% on the small scale system raised peak cumulative efficiencies from 57-63% to 70-74%. Increasing hydrate saturation from 10% to 30% in the medium scale system increased peak cumulative efficiencies from 83% to 90%. During thermal stimulation experiments in both the medium and large scale reactors a flow recirculation pattern developed within the pore space following an initially conduction dominated heat transfer regime. The outward propagation of the heat front from the heating element resulted in increased permeability and the release of mobile water and gas phases as the hydrate underwent dissociation. This change in flow parameters facilitated convection cells within the reactor causing increased heat transfer away from the heating element while displaying a strong upward bias. The flow development detected within the medium scale system was confirmed via history matching of numerical simulation with experimental data. Increased hydrate saturation and increased heating rate lead to a more intense flow development. Thermal stimulation methane production has been coupled with the simultaneous injection of gaseous carbon dioxide as method of enhancing gas production rates while providing a means for long term storage of carbon dioxide in the hydrate phase. The exchange process was investigated at low and high gas injection rates under conditions of both low and high thermal stimulation applied to a 50% hydrate saturated quartz sand pack. The amount of carbon dioxide stored in the hydrate phased was greatest for the low injection-high heating condition sequestering 69 moles, and lowest for the high injection- low heating condition sequestering 13 moles. The gas exchange is improved with longer contact time between gas phase carbon dioxide and hydrate phase methane, this condition is optimized at low carbon dioxide injection rates. The availability of free water for formation of carbon dioxide is enhanced with the higher heating rates. Thus it is possible to tune the gas production rates and carbon dioxide storage potential by manipulating heating rates and gas injection rates to achieve the desired ratio between methane produced and carbon dioxide sequestered. Understanding the transition period and flow development within the pore fluid mixture should play a large role in determining the optimum placement and geometry of heating and exchange systems on industrial scale hydrate production scenarios. In addition to the optimization of thermal stimulation heating location, the profile and degree of heating rate can be tuned in order to maximize gas collection and minimize excessive heating of unproductive sediment matrix after it has been exhausted of methane hydrate. The production efficiency produced across the three experimental scales averaged between 80 and 90% and appears to be independent of scale. The scale up of this method for industrial scale production should pay close attention to the distribution of heat during thermal stimulation as a result of the development of high convective transport that occurs in the near vicinity of the heater and in the dissociated hydrate zone. This work provides supportive evidence that thermal based hydrate dissociation can be achieved with relatively high production efficiencies and satisfactory resource recovery potentials. Further, the CH4-CO2 gas exchange process was successfully coupled with point source thermal stimulation and the influence of injection rate and heating rate on carbon storage potential and methane recovery potential has been demonstrated.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

"Modeling Occurrence and Assessing Public Perceptions of De Facto Wastewater Reuse across the USA." Doctoral diss., 2014. http://hdl.handle.net/2286/R.I.25045.

Повний текст джерела

Анотація:

abstract: The National Research Council 2011 report lists quantifying the extent of de facto (or unplanned) potable reuse in the U.S. as the top research need associated with assessing the potential for expanding the nations water supply through reuse of municipal wastewater. Efforts to identify the significance and potential health impacts of de facto water reuse are impeded by out dated information regarding the contribution of municipal wastewater effluent to potable water supplies. This project aims to answer this research need. The overall goal of the this project is to quantify the extent of de facto reuse by developing a model that estimates the amount of wastewater effluent that is present within drinking water treatment plants; and to use the model in conjunction with a survey to help assess public perceptions. The four-step approach to accomplish this goal includes: (1) creating a GIS-based model coupled with Python programming; (2) validating the model with field studies by analyzing sucralose as a wastewater tracer; (3) estimating the percentage of wastewater in raw drinking water sources under varying streamflow conditions; (4) and assessing through a social survey the perceptions of the general public relating to acceptance and occurrence of de facto reuse. The resulting De Facto Reuse in our Nations Consumable Supply (DRINCS) Model, estimates that treated municipal wastewater is present at nearly 50% of drinking water treatment plant intake sites serving greater than 10,000 people (N=2,056). Contrary to the high frequency of occurrence, the magnitude of occurrence is relatively low with 50% of impacted intakes yielding less than 1% de facto reuse under average streamflow conditions. Model estimates increase under low flow conditions (modeled by Q95), in several cases treated wastewater makes up 100% of the water supply. De facto reuse occurs at levels that surpass what is publically perceived in the three cities of Atlanta, GA, Philadelphia, PA, and Phoenix, AZ. Respondents with knowledge of de facto reuse occurrence are 10 times more likely to have a high acceptance (greater than 75%) of treated wastewater at their home tap.
Dissertation/Thesis
Ph.D. Civil and Environmental Engineering 2014

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Ho, Chia-Yu, and 何家宇. "Thermographic detection and analysis of the temporal and spatial evolution of temperature on the basis of point heat source model upon optical heating of gold nanorod assembly immobilized in agar." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/tqqtma.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Singh, Urisha. "The health-related microbial quality of drinking water from ground tanks, standpipes and community tankers at source and point-of-use in eThekwini Municipality : implications of storage containers, household demographics, socio-economic issues, hygiene and sanitation practices on drinking water quality and health." Thesis, 2009. http://hdl.handle.net/10413/8362.

Повний текст джерела

Анотація:

The aim of this study was to investigate the microbiological quality of drinking water at the source (taps at eThekwini laboratories, standpipes and mobile community tankers) and corresponding point-of-use (storage containers and ground tanks) supplied to peri-urban areas in Durban by eThekwini Municipality. It also aimed to identify factors associated with deterioration in water quality such as storage of water, household demographics, hygiene and sanitation practices. In order to determine the microbial quality of drinking water, the pour plate method (for enumeration of heterotrophic organisms) and the membrane filtration technique (for total coliforms and E. coli enumeration) were used. Conductivity, turbidity, pH and total and residual chlorine levels of drinking water were measured. Microbial and physico-chemical data was collated and statistically analysed with epidemiological data from an associated study to determine the link between microbial quality of drinking water, household demographics, health outcomes, socio-economic status, hygiene and sanitation practices. Findings showed that all point-of-use water was unsafe for human consumption as a result of either poor source water quality, in the case of standpipes, and microbial contamination at the point-of-use, in the case of ground tanks and community tankers. The latter could be attributed to unsanitary environments, poor hygiene practices or poor wateruse behaviour. Households which included children aged 0-5 years and in which open-top containers were used for water storage had the highest rates of diarrhoea and vomiting. Water from ground tanks had the best microbial quality but people in households using this water presented with the highest rate of diarrhoea. Therefore provision of microbially safe drinking water will not reduce the rate of health outcomes if addressed in isolation. In order to reduce water-associated illness, provision of safe and adequate amounts of water, hygiene and sanitation education and education on water-use behaviour should be provided as a package. The provision of improved water delivery systems does not ensure that drinking water is safe for human consumption. Measures, such as point-of-use water treatment should be considered to ensure that drinking water provided at the source and point-of-use is microbially safe for human consumption.
Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Huo, Sheng-chung, and 霍勝中. "Characteristic Analysis of Non-point Sources." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/09584142419335619337.

Повний текст джерела

Анотація:

碩士
朝陽科技大學
環境工程與管理系碩士班
93
This research is based on Non-point source pollution characteristics analysis in Tseng-Wen reservoir. The pollution of water quality is caused on all kinds of land to distribute into control extend is the best method in Tseng-Wen reservoir . Fist collect information to understand on the pollution and condition to the land and use factor analysis to ask for the important parameters and use canonical correlation to understand pollution condition。Then use dummy variable regression to research relevant problems.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Wu, Tung-Hsuan, and 吳東軒. "Analysis of Error Sources in First-order Leveling：Effect of Subsidence of Turning Point." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/41205936488965312292.

Повний текст джерела

Анотація:

碩士
國立成功大學
測量及空間資訊學系碩博士班
94
The way of precise leveling is taking every station forwards step by step. All sections have to observe several times often, and it will be generous that the systemic error is possible accumulated. Because of the high precision, people will be very deeply concerned to the small system error not noticing in the past. At all times, people don’t pay much attention to the subsidence of a spirit level and turning point in leveling. On the one hand, few amount of errors is neglected, on the other, errors could be eliminated when using an order of leveling. Not only on reading, the rods which will change the other side have slight subsidence when the spirit level stands from the odd number to the even station and begins observing. In addition, the value will be accumulated systematically with the number of setups. The study lies in different views analyze TWVD2001 materials which section discrepancies have seriously positive situation, and compare to the Taiwan high speed rail leveling data that needn't use the plates while observing. For this reason, the phenomenon that subsidence of turning point will not happen because it has fixed points per 30~40 meters by the track. We must verify that there are obvious differences in the two materials, and estimate TWVD2001 remaining systematic error correction parameters according to the reason that the error may be accumulated. Besides, we should also infer that remaining systematic error correction parameters caused by rods subsidence but not the movement of turning plate between two setups. In conclusion, through the correction of turning point subsidence. The average of normalized section discrepancies lower from 1.21mm to 0.01mm. It is improved by a wide margin.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Coulson, Adam Lee. "Investigation of the Pre to Post Peak Strength State and Behaviour of Confined Rock Masses Using Mine Induced Microseismicity." Thesis, 2009. http://hdl.handle.net/1807/19183.

Повний текст джерела

Анотація:

As hard rock mining progresses into higher stress mining conditions through either late stage extraction or mining at depth, the rock mass is driven not just to the peak strength, but often well into the post-peak until complete ‘failure’ occurs and easier mining conditions become evident. Limited research has been accomplished in identifying the transition of the rock mass and its behaviour into the post-peak and this research investigates this behaviour in detail. As the rock mass progressively fails, fractures are initiated through intact rock and extension and shear failure of these and pre-existing features occurs. Associated with this failure are microseismic events, which can be used to give an indication of the strength state of the rock mass. Based on an analogy to laboratory testing of intact rock and measurement of acoustic emissions, the microseismicity can be used to identify, fracture initiation, coalescence of fractures (yield), localization (peak-strength), accumulation of damage (post-peak) and ultimate failure (residual strength) leading to aseismic behaviour. The case studies presented in this thesis provide an opportunity to examine and analyse rock mass failure into the post-peak, through the regional and confined failures at the Williams and the Golden Giant mines, both in the Hemlo camp in Northern Ontario, Canada. At the Williams mine, the progressive failure of a sill pillar region into the post-peak was analysed; relating the seismic event density, combined with numerical modelling and a spatial and temporal examination of the principal components analysis (PCA), to characterize the extent, trend and state of the yielding zone, which formed a macrofracture shear structure. Observations of conventional displacement instrumentation, indicates regional dilation or shear of the rock mass occurs at or prior to the point of ‘disassociation’ (breakdown of stable PCA trends) when approaching the residual strength. At the Golden Giant mine, the complete process from initiation to aseismic behaviour is monitored in a highly stressed and confined pendent pillar. The PCA technique, numerical modelling and focal mechanism studies are used to define significant stages of the failure process, in which a similar macrofracture structure was formed. Temporal observations of key source parameters show significant changes prior to and at the point of coalescence and localization.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Lee, Jong-Hwa. "Spatial econometric analysis of a watershed utilizing geographic information systems water quality effects of point and non-point pollution sources in the Neuse River Basin, NC /." 2005. http://www.lib.ncsu.edu/theses/available/etd-12092005-135010/unrestricted/etd.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Wang, Renxiang. "Lithium Ion Battery Failure Detection Using Temperature Difference Between Internal Point and Surface." 2011. http://hdl.handle.net/1805/2979.

Повний текст джерела

Анотація:

Indiana University-Purdue University Indianapolis (IUPUI)
Lithium-ion batteries are widely used for portable electronics due to high energy density, mature processing technology and reduced cost. However, their applications are somewhat limited by safety concerns. The lithium-ion battery users will take risks in burn or explosion which results from some internal components failure. So, a practical method is required urgently to find out the failures in early time. In this thesis, a new method based on temperature difference between internal point and surface (TDIS) of the battery is developed to detect the thermal failure especially the thermal runaway in early time. A lumped simple thermal model of a lithium-ion battery is developed based on TDIS. Heat transfer coefficients and heat capacity are determined from simultaneous measurements of the surface temperature and the internal temperature in cyclic constant current charging/discharging test. A look-up table of heating power in lithium ion battery is developed based on the lumped model and cyclic charging/discharging experimental results in normal operating condition. A failure detector is also built based on TDIS and reference heating power curve from the look-up table to detect aberrant heating power and bad parameters in transfer function of the lumped model. The TDIS method and TDIS detector is validated to be effective in thermal runaway detection in a thermal runway experiment. In the validation of thermal runway test, the system can find the abnormal heat generation before thermal runaway happens by detecting both abnormal heating power generation and parameter change in transfer function of thermal model of lithium ion batteries. The result of validation is compatible with the expectation of detector design. A simple and applicable detector is developed for lithium ion battery catastrophic failure detection.

Стилі APA, Harvard, Vancouver, ISO та ін.

Дисертації з теми "Point source analysis"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями