Global ETD Search

1	Experimental Practice in order to Increasing Efficiency of Biogas Production by Treating Digestate Sludge. Khorshidi, Nasrin, Arikan, Beyza January 2008 (has links) According to national and international policies in order to protect environment regarding renewable sources of energy, biogas is one of the best alternative to reduce waste and pollution and getting energy. Biogas is the gas that is produced by some kinds of microorganisms in anaerobic condition from organic waste treatment. Technology of biogas plants is varies and there is no standard procedure that is applicable worldwide. Methane (biogas), which is produced from wastes and it is known widely since 1973. By organic waste degradation methane is produced and waste volume will be reduced. Some surveys prove that during anaerobic digestion only 50% of organic matter is degraded. Anaerobic degradation has some steps that are hydrolysis, acidogenesis, acetogenesis and methanogenesis. Since hydrolysis is rate-limited step it can be improved by some pretreatment and some action like improving monitoring system can show that the efficiency of biogas will increase. There are three main pretreatment methods. During this study digestate sludge from different waste treatment plants were pretreated. First experience was pretreating digestate sludge from Sobacken, Falköping, Västerås by Enzyme Addition (Cellolase) and the measuring of biogas (methane) has done by Gas Chromatograph (GC). Second experience was pretreating digestate sludge by Acid (Sulfuric acid). The data of those measurements are shown that the amount of biogas was increased two times in the case of Västerås by enzyme addition, which is about 70% of theoretical expectation of this pretreatment and pretreating digestate sludge of Sobacken by acid pretreatment could increase the amount of biogas two times as well that was about 60% of theoretical estimation. By proper gas chromatograph and choosing one kind of waste and pretreating that by just one kind of pretreatment in each experience and following the results and going further the biogas efficiency will increase significantly because still 50% organic matter is inside the digester. / Uppsatsnivå: D biogas increasing efficiency pretreatment enzymatic acidic Engineering and Technology Teknik och teknologier
2	AC Direct Drive LED Lighting Using Low Cost Analog Components Head, Miles 01 May 2019 (has links) This project explores the rapidly expanding area of AC direct drive for LED lighting. AC LED driving does not use typical DC-DC converter-based driving but uses semiconductor switches and a linear regulator to activate a number of LEDs proportional to the input voltage at any given time. This allows bulky, expensive magnetics to be eliminated from the system. The goal of this project was to design a scaled-down physical AC LED direct drive system to validate the conclusions of methods for improving efficiency from a previous investigation that found minimizing voltage across the linear regulating MOSFET led to higher efficiency at the cost of increased input current THD. This project found that this conclusion is physically realizable, with a final efficiency of 94.46% and an input current THD of 58.9%. This result was achieved by taking the previous investigation’s final design as a starting point and replacing ideal switches and control signals with discrete components. The final version uses a set of comparators and sense resistors to determine when a given LED stack should be on for a simple, analog control solution. Once the system was simulated this way, the assembled version was used to measure efficiency, power factor, current THD, flicker index, and DC supply power. Additional plots of the stack voltages and control signals were collected to verify proper operation and compare to simulation. The final measurements aligned with trends from simulation and result in a simple AC direct drive solution that requires no specialty ICs. AC direct drive LED linear regulator increasing efficiency Electrical and Electronics
3	Návrh a implementace nového procesu pro Call Centrum konkrétní organizace / Design and Implementation of New Process for Call Center for Concrete Organization Kyselová, Petra January 2010 (has links) This paper deals with the definition of Corporate Communication and the specifics of telephonic communication with the customer, and further definition of the Process and Process Management focused on process analysis ,which is part of the practical part. Extensive section is devoted to practical study. The benefit of this paper is a comprehensive view at the business model of BEZREKLAMKY s.r.o. The paper deals with analyzing the present state of business model, under which are determined possibilities to increase the efficiency of the process. The last part is devoted to assess the advisability of establishing cooperation at a distance by phone. This process is designed with all the formalities so that it can be directly imlplemented into the current model.
4	Zvýšení efektivity výroby na linkách MCA s pájecími roboty / Increasing efficiency of MCA production lines with solder robots Hajný, Pavel January 2016 (has links) This master thesis describes the design of increasing the efficiency of production lines with solder robots. In beginning of this work is a description of product and current process. There are also variants of design solutions for soldering palettes and the best on is chosen. The last part of this work includes design automation soldering process.
5	Polismyndighetens utredning av sexuellt digitalt våld mot barn : En kvalitativ studie om praktikers upplevelser och erfarenheter kring hinder och förutsättningar i utredningsarbetet samt praktikernas eventuella påverkan av arbetet Markfjärd, Cecilia, Mehanna, Diana, Olofsson, Jennie January 2019 (has links) Föreliggande studie har genom nio semi-strukturerade kvalitativa intervjuer undersökt utredares, förundersökningsledares samt åklagares upplevelser och erfarenheter inom Polismyndighetens utredningsarbete, vad gäller sexuellt digitalt våld mot barn (under 18 år). Detta för att eventuellt kunna identifiera möjliga utvecklingsområden inom utredningsarbetet vad gäller att skicka oönskade nakenbilder samt att otillåtet sprida nakenbilder på någon annan. Detta då uppklaringsandelen i relation till antalet anmälningar vad gäller dessa brott kan anses vara låg. Således blev praktikers upplevelser och erfarenheter av arbetsprocessen samt om och i sådana fall hur de påverkas av att arbeta med sexuellt digitalt våld centralt. Resultatet påvisar att praktikerna lyfter flera aspekter av sitt arbete såsom bra ledarskap, utformningen av arbetsgrupper samt snabba samarbeten som välfungerande moment i utredningsarbetet. Flera utvecklingsområden framkom även där det bland annat efterfrågas klarare riktlinjer, samt mer metodstöd, kunskap och utbildning inom området för att öka effektiviteten i arbetet. Exponeringen i deltagarnas arbete med sexuellt digitalt våld mot barn, tillsammans med den stress praktikerna upplever utifrån deras arbetsbelastning, erfars bidrar till en negativ påverkan och minskad arbetskapacitet. Dock belyses att stöd och hjälp finns att tillgå som motverkar den negativa påverkan. Studiens resultat diskuteras utifrån tidigare forskning inom området samt i relation till organisationsteori. / The present study has, through nine qualitative semi-structured interviews, examined investigators’, requisitors’ and prosecutors’ experiences of the police authority's investigative work regarding sexual digital violence against children (under age 18). The study aimed to identify areas of development within the investigative work regarding receiving unwanted nude images and unauthorized spreading of nude pictures of others. This because of the low crime clearance rate of reported crimes. Thus practitioners’ experience of their work process, including if and how they were affected by working with sexual digital violence, were essential. The results from the interviews highlighted several aspects of the work such as good leadership, team design, and rapid collaborations as well-functioning components. Several areas of development also emerged such as clearer guidelines, increased methodological support, increased level of knowledge, and education, to increase the work efficiency. The exposure to sexual content in the participants' work combined with the stress derived from their workload was experienced to contribute to a negative impact and reduced work capacity. However, it was highlighted that support and help was available to lessen the negative impact. The study's results were discussed based on previous research in the field and in relation to organizational theory. sexual digital violence investigative work impact possibility of increasing efficiency Regional cyber crime centre Police authority. sexuellt digitalt våld utredningsarbete effektiviseringsmöjligheter påverkan Regionalt IT-brottscentrum Polismyndigheten. Other Social Sciences Annan samhällsvetenskap
6	Entwicklung und Evaluation eines Gewichtsfenstergenerators für das Strahlungstransportprogramm AMOS Jakobi, Christoph 19 March 2018 (has links) (PDF) Effizienzsteigernde Methoden haben die Aufgabe, die Rechenzeit von Monte Carlo Simulationen zur Lösung von Strahlungstransportproblemen zu verringern. Dazu gehören weitergehende Quell- oder Geometrievereinfachungen und die Gewichtsfenstertechnik als wichtigstes varianzreduzierendes Verfahren, entwickelt in den 1950er Jahren. Die Schwierigkeit besteht bis heute in der Berechnung geeigneter Gewichtsfenster. In dieser Arbeit wird ein orts- und energieabhängiger Gewichtsfenstergenerator basierend auf dem vorwärts-adjungierten Generator von T.E. BOOTH und J.S. HENDRICKS für das Strahlungstransportprogramm AMOS entwickelt und implementiert. Dieser ist in der Lage, die Gewichtsfenster sowohl iterativ zu berechnen und automatisch zu setzen als auch, deren Energieeinteilung selbstständig anzupassen. Die Arbeitsweise wird anhand des Problems der tiefen Durchdringung von Photonenstrahlung demonstriert, wobei die Effizienz um mehrere Größenordnungen gesteigert werden kann. Energieabhängige Gewichtsfenster sorgen günstigstenfalls für eine weitere Verringerung der Rechenzeit um etwa eine Größenordnung. Für eine praxisbezogene Problemstellung, die Bestrahlung eines Personendosimeters, kann die Effizienz hingegen bestenfalls vervierfacht werden. Quell- und Geometrieveränderungen sind gleichwertig. Energieabhängige Fenster zeigen keine praxisrelevante Effizienzsteigerung. / The purpose of efficiency increasing methods is the reduction of the computing time required to solve radiation transport problems using Monte Carlo techniques. Besides additional geometry manipulation and source biasing this includes in particular the weight windows technique as the most important variance reduction method developed in the 1950s. To date the difficulty of this technique is the calculation of appropriate weight windows. In this work a generator for spatial and energy dependent weight windows based on the forward-adjoint generator by T.E. BOOTH and J.S. HENDRICKS is developed and implemented in the radiation transport program AMOS. With this generator the weight windows are calculated iteratively and set automatically. Furthermore the generator is able to autonomously adapt the energy segmentation. The functioning is demonstrated by means of the deep penetration problem of photon radiation. In this case the efficiency can be increased by several orders of magnitude. With energy dependent weight windows the computing time is decreased additionally by approximately one order of magnitude. For a practice-oriented problem, the irradiation of a dosimeter for individual monitoring, the efficiency is only improved by a factor of four at best. Source biasing and geometry manipulation result in an equivalent improvement. The use of energy dependent weight windows proved to be of no practical relevance. Effizienzsteigerung Monte-Carlo Monte-Carlo-Simulation AMOS Simulation Gewichtsfenster Gewichtsfenstertechnik Gewichtsfenstergenerator Strahlungstransport tiefe Durchdringung vorwärts-adjungiert Varianzreduktion Quellveränderungen Geometrieveränderungen Russisch Roulette Teilchensplitting Increasing efficiency Monte Carlo Monte Carlo simulation AMOS simulation weight windows weight window technique weight window generator radiation transport deep penetration forward-adjoint variance reduction source biasing geometry manipulation Russian roulette particle splitting ddc:530 rvk:UN 3020 Effizienzsteigerung Monte-Carlo Monte-Carlo-Simulation AMOS Simulation Gewichtsfenster Gewichtsfenstertechnik Gewichtsfenstergenerator Strahlungstransport tiefe Durchdringung vorwärts-adjungiert Varianzreduktion Quellveränderungen Geometrieveränderungen Russisch Roulette Teilchensplitting Increasing efficiency Monte Carlo Monte Carlo simulation AMOS simulation weight windows weight window technique weight window generator radiation transport deep penetration forward-adjoint variance reduction source biasing geometry manipulation Russian roulette particle splitting
7	Entwicklung und Evaluation eines Gewichtsfenstergenerators für das Strahlungstransportprogramm AMOS Jakobi, Christoph 13 March 2018 (has links) Effizienzsteigernde Methoden haben die Aufgabe, die Rechenzeit von Monte Carlo Simulationen zur Lösung von Strahlungstransportproblemen zu verringern. Dazu gehören weitergehende Quell- oder Geometrievereinfachungen und die Gewichtsfenstertechnik als wichtigstes varianzreduzierendes Verfahren, entwickelt in den 1950er Jahren. Die Schwierigkeit besteht bis heute in der Berechnung geeigneter Gewichtsfenster. In dieser Arbeit wird ein orts- und energieabhängiger Gewichtsfenstergenerator basierend auf dem vorwärts-adjungierten Generator von T.E. BOOTH und J.S. HENDRICKS für das Strahlungstransportprogramm AMOS entwickelt und implementiert. Dieser ist in der Lage, die Gewichtsfenster sowohl iterativ zu berechnen und automatisch zu setzen als auch, deren Energieeinteilung selbstständig anzupassen. Die Arbeitsweise wird anhand des Problems der tiefen Durchdringung von Photonenstrahlung demonstriert, wobei die Effizienz um mehrere Größenordnungen gesteigert werden kann. Energieabhängige Gewichtsfenster sorgen günstigstenfalls für eine weitere Verringerung der Rechenzeit um etwa eine Größenordnung. Für eine praxisbezogene Problemstellung, die Bestrahlung eines Personendosimeters, kann die Effizienz hingegen bestenfalls vervierfacht werden. Quell- und Geometrieveränderungen sind gleichwertig. Energieabhängige Fenster zeigen keine praxisrelevante Effizienzsteigerung.:1 Einleitung 2 Theoretische Grundlagen 2.1 Strahlungsfeldgrößen und Strahlungstransportgleichung 2.2 Monte Carlo Methoden 2.3 Effizienzsteigernde Methoden 3 Gewichtsfenstergenerator 3.1 Güte der Ergebnisse 3.2 Iterative Berechnung 3.3 Implementation in AMOS 4 Anwendungsbeispiele 4.1 Tiefe Durchdringung von Photonenstrahlung 4.2 Gestreute Photonenstrahlung 5 Zusammenfassung und Ausblick 6 Literatur Anhänge / The purpose of efficiency increasing methods is the reduction of the computing time required to solve radiation transport problems using Monte Carlo techniques. Besides additional geometry manipulation and source biasing this includes in particular the weight windows technique as the most important variance reduction method developed in the 1950s. To date the difficulty of this technique is the calculation of appropriate weight windows. In this work a generator for spatial and energy dependent weight windows based on the forward-adjoint generator by T.E. BOOTH and J.S. HENDRICKS is developed and implemented in the radiation transport program AMOS. With this generator the weight windows are calculated iteratively and set automatically. Furthermore the generator is able to autonomously adapt the energy segmentation. The functioning is demonstrated by means of the deep penetration problem of photon radiation. In this case the efficiency can be increased by several orders of magnitude. With energy dependent weight windows the computing time is decreased additionally by approximately one order of magnitude. For a practice-oriented problem, the irradiation of a dosimeter for individual monitoring, the efficiency is only improved by a factor of four at best. Source biasing and geometry manipulation result in an equivalent improvement. The use of energy dependent weight windows proved to be of no practical relevance.:1 Einleitung 2 Theoretische Grundlagen 2.1 Strahlungsfeldgrößen und Strahlungstransportgleichung 2.2 Monte Carlo Methoden 2.3 Effizienzsteigernde Methoden 3 Gewichtsfenstergenerator 3.1 Güte der Ergebnisse 3.2 Iterative Berechnung 3.3 Implementation in AMOS 4 Anwendungsbeispiele 4.1 Tiefe Durchdringung von Photonenstrahlung 4.2 Gestreute Photonenstrahlung 5 Zusammenfassung und Ausblick 6 Literatur Anhänge info:eu-repo/classification/ddc/530 ddc:530

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