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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

VALIDAÇÃO DO USO DO EQUIPAMENTO ISPEC Q100 NO CONTROLE DE QUALIDADE DA MISTURA DIESEL-BIODIESEL / VALIDATION OF USE OF EQUIPMENT ISPEC Q100 IN THE QUALITY CONTROL OF THE MIX-DIESEL BIODIESEL

Salomão, Rondineli Seba 01 March 2011 (has links)
Made available in DSpace on 2016-08-19T12:56:40Z (GMT). No. of bitstreams: 1 dissertacao Rondineli.pdf: 1327315 bytes, checksum: 6cc6c1453c994985899fa283f8572aef (MD5) Previous issue date: 2011-03-01 / Nowdays, biodiesel s standardization for quality control in Brazil comprises two standard groups and within these methods, validation is essential to ensure the success in fuel s quality control. The aim of the present work was validating the use of the equipment I-SPEC in analysis of biodiesel blends with diesel, from a mixed matrix (vegetable, animal). The equipment, based on spectroscopy impedance, analyzes four parameters in biodiesel (total glycerol content, acidity index, residual content of methanol and biodiesel blend in diesel). The procedure involved analyzes of biodiesel, blends of biodiesel:diesel, and diesel samples by infrared (FT-IR) technique, correlation curves analysis of IV x I-SPEC in duplicate, quintuplicate sample and different analysts. The obtained data were subjected to the Z Score test (Zanalist1 = 0.0 and Zanalist2= 0.335) and the Student's T test (tcalculated1 = 0.0 and tcalculated2 = 0.75), with 95% level of confidence and 4 degrees of freedom, demonstrating that the method generates real results, compared to the standard technique (FT-IR). Correlation I-SPEC x FT-IR showed good linearity (r = 0.997) and low relative difference (error < 2.0%) ensuring that the methodology can be applied to study blend with equivalence of results, within their limitations of precision, and contemplating the content of biodiesel in diesel, currently regulated by Brazilian legislation (5%). The equipment provides portability, low maintenance costs and low complexity of operation compared to standard techniques (FT-IR, CG, HPLC) and therefore could be used in field assessments. As disadvantage, we can mention: the use of sensors limited to only once, the results are generated for biodiesel blends (biodiesel:diesel) in absolute values (with only one significant figure), the method will not be able to detect contamination of biodiesel with vegetal oil, the need of the equipment be used in environment with low temperature variation (± 1.0 º C) to perform the analysis. With the results from this study can be concluded that, even considering the disadvantages, the new procedure is similar, in terms of applicability to standard method, FT-IR. So the I-SPEC equipment appears sufficient to allow the determination of biodiesel blends : diesel, within the range studied (2% to 10%), ensuring security of the analytical results studied. / A normatização vigente para o controle de qualidade de biodiesel no Brasil engloba dois grupos de parâmetros e dentro destes a validação de métodos é um ponto essencial para a garantia do sucesso e controle de qualidade dos combustíveis. O objetivo deste trabalho foi o de validar o uso do equipamento I-SPEC na análise de misturas biodiesel:diesel, provenientes de uma matriz mista (vegetal:animal). O equipamento baseado em espectroscopia de impedância avalia quatro parâmetros no biodiesel (teor de glicerol total, índice de acidez, teor de metanol residual e teor de biodiesel no diesel). O procedimento envolveu etapas de avaliação de amostras de biodiesel, diesel e misturas biodiesel:diesel, por Infravermelho, análise de correlação entre as curvas IV x I-SPEC em duplicata, quintuplicata e diferentes analistas. Os dados obtidos foram submetidos ao teste de Z Score (Zanalista1=0,0 e Z analista2 = 0,335) e ao teste t de Student (tcalculado1 = 0,0 e tcalculado2 = 0,75), com nível de confiança de 95% e 4 graus de liberdade demonstrando que o método gera resultados confiáveis, comparados à técnica padrão (FT-IR). A correlação I-SPEC x FT-IR demonstrou boa linearidade (r=0,997) e baixa diferença entre os métodos (Erro Relativo <2,0%), garantindo que a metodologia do I-SPEC pode ser aplicada à matriz proposta com equivalência de resultados, dentro de suas limitações de precisão, e contemplando a faixa de teor de Biodiesel no diesel, regulamentada atualmente pela legislação brasileira (5%). O novo equipamento oferece portabilidade, baixo custo de manutenção e baixa complexidade de operação, se comparado às técnicas padrão (FT-IR, CG, HPLC) podendo assim ser utilizado em avaliações de campo. Como desvantagem, podemos citar: o uso dos sensores limitado a uma única vez; o fato dos resultados para as misturas de biodiesel no diesel (biodiesel:diesel) serem gerados em valores absolutos (com apenas um algarismo significativo); o método não foi sensível para quantificar contaminações do biodiesel com óleo vegetal; resultados dependentes da estabilidade terminca do ambiente (±1,0ºC) para realização das análises. Com os resultados obtidos a partir do presente estudo, pode-se concluir que, mesmo considerando as desvantagens, o procedimento avaliado é semelhante, em termos de aplicabilidade, ao método padrão (FT-IR), apresentado comportamento satisfatório para a determinação de misturas biodiesel:diesel, dentro da faixa estudada (2% a 10%), garantindo segurança analítica dos resultados estudados.
22

A Comparison of Three Computer System Simulators

Urdén, Ulf January 2004 (has links)
This thesis is a comparative study of three computer system simulators. These computer programs are commonly used to test the efficiency and feasibility of new computer architectures, as well for debugging and testing software. With this study, we evaluate the fundamental differences of three simulators: SimICS, SimpleScalar and ML-RSIM. A comprehensive study of simulation techniques is presented, and each evaluated simulator is classified using those premises. Quantification the performance differences using a benchmark suite is made. The results show that the most feature-rich of the simulators also seems to have the highest performance in the group.
23

Recasting Narratives: Accessing Collective Memory of the Vietnam War in Modern Popular Media Texts

Wertsch, Tyler 01 May 2019 (has links)
No description available.
24

Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

Brendler, Vinzenz, Claussner, Juergen, Proehl, Dieter, Reichel, Peter, Matz, Wolfgang, Dienel, Siegfried, Reich, Tobias, Funke, Harald, Schell, Norbert, Strauch, Udo, Berberich, Florian, Oehme, Winfried, Hennig, Christoph, Prokert, Friedrich, Neumann, Wolfgang, Krug, Hans, Bernhard, Gert 31 March 2010 (has links) (PDF)
Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen.
25

Nestabilita řezu při dělení mezních tlouštěk plechů laserovým paprskem / Unstability cut of laser beam at dividing limiting gauge thickness

Kadlec, Zdeněk January 2008 (has links)
This thesis deals with the possibilities of cutting strong steel metal sheets by means of laser and problems rising from the incision, their technological investigation. The basic philosophy consists on the research of the interaction between laser bunch and material, depending on the position of focal poin and sequential results in spec. heat. It determines the main parametres of the incision (from the total quantities and matematical description) which have the biggest effect on the occurence of wide cut and perhaps even on the quality of products and consequential optimalization of these quantities.
26

Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

Brendler, Vinzenz, Claussner, Juergen, Proehl, Dieter, Reichel, Peter, Matz, Wolfgang, Dienel, Siegfried, Reich, Tobias, Funke, Harald, Schell, Norbert, Strauch, Udo, Berberich, Florian, Oehme, Winfried, Hennig, Christoph, Prokert, Friedrich, Neumann, Wolfgang, Krug, Hans, Bernhard, Gert January 2000 (has links)
Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen.
27

A SYNERGETIC APPROACH TO PRODUCE DURABLE, HIGHLY RECYCLED PAVEMENT MIXTURES

Abdalla, Ahmed, 0000-0001-5558-2405 January 2022 (has links)
Recently, Sustainable engineering has become a necessity due to the limited availability of virgin materials, environmental concerns, and the lack of economic resources. According to the United Nations, "Sustainable engineering is the process of using resources in a way that does not compromise the environment or deplete the materials for future generations." However, developing cost-efficient and long-term road infrastructure has always been a challenge. Therefore, novel solutions are required to extend the pavement life cycle and minimize raw materials utilization to overcome this challenge. This research focuses on integrating the waste material to produce rheological engineered asphalt mixtures as pavement material. This study utilized three wastes, which are Off-spec fly ash (OFA), Reclaimed Asphalt Pavement (RAP), and finally, a bio-oil extracted from Spent Coffee Ground (SCG). OFA is a viable source for recycling due to the quantities produced yearly and deposited in landfills. For many years fly ash has been effectively used as a partial replacement for Portland cement in producing different types of concrete, embankments, and soil stabilization. Most of the underutilized fly ash is Off-Spec. That was the motive behind adopting the OFA in this study. This study aims to investigate the fly ash's interaction with the asphalt binder as an additive rather than a filler. Few studies evaluated this hypothesis regarding fly ash as an additive. Moreover, this research's novelty comes as there is a lack of research evaluating the fly ash-asphalt physio-chemical interaction. RAP utilization in roads infrastructure became a current state of practice. Most state Departments of Transportation (DOTs) have been using RAP at a composition average of about 20% of the mix by mass. This study focuses on maximizing the utilization of the RAP content through using a bio-oil extracted from the SCG as a new promising rejuvenator. Spent coffee ground is not well recycled, and almost six million tons are sent to landfills every year. This waste was found to release methane into the atmosphere; methane is the second-most abundant greenhouse gas and has a global warming potential up to 86 times greater than CO2, which is highly harmful to the environment. In this study, the overreaching goal is to develop a green, innovative, and sustainable approach by recycling three different types of wastes (OFA, RAP, and SCGO) to achieve high-performance asphalt pavements. In addition, this study documents the science-based approach to successfully integrating these wastes as substitutes to the asphalt binder. Results show that some OFAs are associated with improved rheological performance, damage healing, and cracking resistance as an asphalt binder additive. The improvement is attributed to the level of interaction between the binder and the physical and chemical characteristics of the OFA. The use of rejuvenators further improved the aging resistance of the ash blends, suggesting high potential synergy, especially the proposed SCGO rejuvenator, which promotes utilizing it as a promising eco-friendly rejuvenator in the asphalt pavement industry. After engineering a product built by OFA and rejuvenators, these results have been validated by mixtures’ scale testing. 62% optimum RAP content is suggested to be utilized with an 11% dosage of the proposed SCGO rejuvenator as binder replacement. For the new engineered OFA/rejuvenators products, a 30% optimum RAP content is suggested to be used. Finally, Life Cycle Assessment (LCA) is conducted to evaluate the environmental potential of utilizing multi recycled materials in the Hot Mix Asphalt (HMA) industry. The results show a reduction in environmental impacts with RAP utilization and the new eco-friendly products (OFA and SCGO rejuvenator). Shifting HMA plant fuel to natural gas instead of Heavy Fuel Oil (HFO) offers considerable potential environmental benefits. Adopting the Ultrasonic Assisted-oil Extraction (UAE) as SCGO rejuvenator extraction method showed less energy and solvent consumption than the Soxhlet extraction, resulting in less environmental impacts. / Civil Engineering
28

Characterization of two unique pathways for wyosine biosynthesis in Kinetoplastids

Sample, Paul J. 09 September 2014 (has links)
No description available.
29

Prospects for the beneficial use of arbuscular mycorrhizal fungi in horticulture in combination with organic and inorganic fertilizers

Perner, Henrike 28 November 2006 (has links)
Aufgrund seines Nährstoffaneignungsvermögens und Stimulierung des Pflanzenmetabolismus kann der Arbuskuläre Mykorrhiza (AM) Pilz im Gartenbau nutzbringend eingesetzt werden. Der Fokus der Arbeit liegt auf den Möglichkeiten des AM Pilzes a) pflanzenernährerische Probleme zu lösen, b) die Blütenbildung bei Zierpflanzen zu steigern und c) das Gesundheitspotential von Gemüse für den Menschen zu erhöhen (sekundäre Pflanzenmetaboliten). Zur Lösung pflanzenernährerischer Probleme wurden Porree, Pelargonie und Poinsettie auf Torf-Substraten mit 20% und 40% Kompostzusatz untersucht. Ferner wurde Salat auf Torf-Substrat mit drei P Behandlungen getestet: substrateigenes P, Rohphosphat und lösliches P. Frühlingszwiebeln und Schnittknoblauch wurden in Nährlösungen auf Perlit mit niedrigem, mittlerem und hohem NH4+/NO3- Verhältnis ernährt. Gemessen wurde die AM Kolonisation, die Trockenmasse und die N, P, K, S, NO3-, Mg und Zn Konzentrationen im Spross. Die Blütenbildung von Pelargonien und Poinsettien wurde auf Torf-Kompost-Substraten untersucht. Der Einfluss auf die sekundäre Metaboliten von Frühlingszwiebeln und Schnittknoblauch wurde zusammen mit drei NH4+/NO3- Verhältnissen geprüft (s.o.). Untersucht wurden Glukose, Fruktose, Saccharose, lösliche Feststoffe und organische Schwefelverbindungen (gemessen als Pyruvat). Eine AM Kolonisation konnte die Nährstoffversorgung der Pflanze verbessern und die Blütenbildung erhöhen. Jedoch profitierten die Pflanzen unter den beschriebenen experimentellen Bedingungen nicht durchgängig in ihrem Wachstum und Metaboliten vom AM Pilz. Die Zugaben von Kompost ermöglichte die Verbesserung der Substratqualität für die Nährstoffversorgung und das Pflanzenwachstum unter ökologischen Gartenbaubedingungen. Der Ertrag von gesundheitsfördernden organischen Schwefelverbindungen konnte in Abhängigkeit von der jeweiligen Allium Spezies, durch eine Variation des Ammonium/Nitrat Verhältnissen und/oder durch einen AM Effekt auf das Wachstum gesteigert werden. / Arbuscular mycorrhizal (AM) fungi can be beneficial for horticultural crops due to their nutrient acquisition properties and stimulation of the plant metabolism. The present work focuses on the prospects of AM fungi a) to solve plant nutritional problems, b) to induce flower development of ornamental plants, and c) to improve the health potential of crop plants for humans. Contribution of AM fungi to plant nutritional problems were investigated with leek, pelargonium and poinsettia plants on peat-based substrates with 20% and 40% compost additions. Moreover, lettuce plants were supplied on peat-based substrates with substrate own P, rock phosphate, or highly soluble P. Bunching onion and chinese chive were propagated on perlite in nutrient solution with low, medium and high NH4+:NO3- ratios. Mycorrhizal colonization, dry weight, and N, P, K, S, NO3-, Mg and Zn concentrations in plants were measured. Mycorrhizal effects on bud and flower development of pelargonium and poinsettia plants were investigated on peat-based compost substrates. Treatment effects on secondary metabolites in bunching onion and chinese chive were determined by exposing mycorrhizal and non mycorrhizal plants to three NH4+:NO3- supply ratios. The metabolites measured were glucose, fructose, and sucrose, total soluble solids, and organosulfur compounds (measured as pyruvic acid). Colonization improved plant nutrient status and flower development. Under the described experimental conditions, however, plants did not consistently benefit in growth or plant composition from the mycorrhizal symbiosis. Additions of compost were a means of improving the substrate quality for an increased plant nutrient acquisition and plant growth in organic horticulture. The plant quality of Allium species in respect to organosulfur compounds was increased by taking the individual Allium species into consideration, their specific requirements for an optimal NH4+:NO3- supply ratio, and a possible AM effect on plant growth.
30

The metabolic sequelae of oesophago-gastric resection

Roberts, Geoffrey Peter January 2019 (has links)
Bypass or resection of the stomach and oesophagus, has long been recognised to result in profound changes in the handling of ingested nutrients. This results in significant morbidity after radical surgery for oesophago-gastric cancer, in particular post-prandial hypoglycaemia, altered appetite, early satiety and noxious post-prandial symptoms. By profiling and challenging the gut hormone axis in healthy volunteers and patients who had undergone total or subtotal gastrectomy, or oesophagectomy, this thesis explores the possible causative mechanisms for the challenges faced by this patient population. In the surgical groups, an oral glucose tolerance test (OGTT) resulted in enhanced secretion of satiety and incretin gut hormones (GLP-1, GIP, PYY) and insulin, followed by hypoglycaemia in a cohort of patients. Continuous glucose monitoring of gastrectomy participants over two weeks of normal lifestyle identified an increased incidence of day and night time hypoglycaemia. RNAseq and mass spectrometry based peptidomics of human and murine enteroendocrine cells in the pre- and post-operative populations revealed no significant change in the underlying cellular pathways for nutrient sensing and gut hormone secretion, indicating that the altered hormone secretion is primarily driven by accelerated nutrient transit, rather than adaptive changes in the gut. Finally, specific blockade of the GLP-1 receptor in post-gastrectomy patients using Exendin 9-39 normalised insulin secretion and prevented reactive hypoglycaemia after an OGTT. In conclusion, profound changes in gut hormone secretion as a result of enhanced nutrient transit after foregut surgery likely underlie the early and late post-prandial symptoms seen in this group, and therapies specifically targeting the gut hormone axis, and GLP-1 in particular, could be the first targeted treatments for post-gastrectomy syndromes.

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