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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

Stormwater modelling tools : a comparison and evaluation

Lind, Johanna January 2015 (has links)
Stormwater is rain, melt and rinse water that temporarily runs off the ground surface. In cities with many impermeable surfaces large amounts of stormwater may be formed. Stormwater is diverted through conduits and ditches to recipients. If the diversion of stormwater is insufficient flooding can occur. Stormwater contains contaminants from the catchment surfaces such as nutrients, heavy metals, bacteria, organic compounds and oils. To study stormwater pollution and flows various stormwater modelling tools are used. The purpose of this thesis is to test, compare and evaluate four stormwater modelling tools and conclude their strengths and weaknesses. This was done by a literature study, a market research, definition of evaluation criteria and by testing the tools on a case study of an industrial and residential area in Scotland. The main developed evaluation criteria was model characteristics, required input, user friendliness, output and model application. The four selected tools were StormTac, Infoworks CS, SuDS Studio and MUSIC. The case study included both flow and pollutants on a yearly basis and for a rainfall event. The results from the study were compared against observed values both before and after calibration. No model gave good model predictions for all parameters. The observed volumes of water were larger than modelled for all four models even after calibration. An intercomparison between the models however gave a better fit. Regarding pollutants, the model predictions compared with observed values varied between the tools and substances. Strengths with StormTac are that it includes over 70 pollutants, includes the recipient and gave good model predictions for pollutant concentrations when compared with observed pollutants. A weakness is that StormTacs automatically calculated base flow was much smaller than observed in the case study and the tool is not suited for studies of single event rainfalls.Strengths with Infoworks CS are that it is fully distributed, a complete network is built up and the tool can be used for design of networks, flood predictions and flows over time. It is time consuming to build a model in Infoworks CS, few default pollutants are included and it gave poor model predictions for nitrogen concentrations in the case study. SuDS Studio is a unique tool for defining suitable options for retrofitting SuDS solutions and this is a strength as it is the only tool of its kind. SuDS studio gave large intervals for pollutant loads in the case study which can be difficult to interpret. A strength with MUSIC is that it is user friendly and can be used for comparing water quality pre and post treatment. It does however only include three default pollutants in the model, and only three pollutants can be modelled at a time.
22

Desenvolvimento de procedimentos analíticos para a determinação de não-metais via moléculas diatômicas por espectrometria de absorção molecular de alta resolução com fonte contínua / Development of analytical procedures for the determination of non-metals via diatomic molecules by high-resolution continuum source molecular absorption spectrometry

Flávio Venâncio Nakadi 21 July 2015 (has links)
A espectrometria de absorção atômica (AAS) é consolidada como uma técnica robusta, cujas aplicações estendem-se a diversos analitos e matrizes. Sua limitação encontra-se na região do UV distante (~ 190 nm), por isso ela permaneceu exclusiva à determinação de metais durante vários anos: não-metais geralmente absorvem na região de UV de vácuo. Com o advento da AAS de alta resolução com fonte contínua, houve a implementação de uma terceira dimensão (comprimento de onda) nas análises: a visualização da região espectral da linha analítica. Esta nova característica permitiu um maior número de informações espectrais, principalmente em relação às bandas estruturadas de moléculas diatômicas, o que resultou na determinação de absorção molecular (HR CS MAS). Destarte, o objetivo deste trabalho foi a elaboração de novos procedimentos analíticos para determinação de não-metais por HR CS MAS, especificadamente Br, Cl e S, com atomizador de forno de grafite. O bromo foi avaliado via CaBr em componentes plásticos de amostras eletrônicas, extraído por extração Soxhlet com tolueno, e obteve limites de detecção (LD) e quantificação (LQ) de 4,3 e 14 ng de Br, respectivamente, com Pd como modificador químico. Duas matrizes foram estudadas para a quantificação de enxofre via CS: carvão e diesel. O carvão foi injetado em HR CS MAS como uma suspensão com Triton X-100 0,04 % m v-1, e (NH4)2SO4 foi empregado como padrão de enxofre. Os LD e LQ obtidos para o método foram 0,01 e 0,05 % m m-1, respectivamente. Para o diesel, dois métodos foram estudados: (i) emulsão alcoólica com etanol 50 % v v-1, a qual apresentou LD de 0,12 g kg-1 e LQ de 0,40 g kg-1, adequados para determinação de altos teores de S em diesel; e (ii) injeção direta de diesel no sistema de HR CS MAS, cujos LD e LQ foram 3 e 9 mg kg-1, respectivamente. Ambos empregaram nanopartículas de Pd como modificador químico, das quais a análise direta de diesel obteve melhores resultados. Finalmente, um novo conceito foi investigado em HR CS MAS: o deslocamento isotópico em moléculas diatômicas. Os estados vibracionais e rotacionais presentes na transição eletrônica observada em HR CS MAS confere esta propriedade. As moléculas de AlCl e CaBr, cujos isótopos de interesse foram 35Cl e 37Cl, e 79Br e 81Br, respectivamente, foram estudadas. Os deslocamentos isotópicos observados foram de 15,6 pm para AlCl e 41,6 pm para CaBr nos comprimentos de onda selecionados, suficientes para implementação de calibração por diluição isotópica, a qual apresentou LDs de 2,5 e 64 ng, respectivamente. Amostras de água natural e mineral foram empregadas para o Cl, enquanto o Br foi determinado em amostras de PVC e folhas de tomate, as quais foram introduzidas diretamente como sólidos. A diluição isotópica corrigiu adequadamente as interferências espectrais acarretadas pelas matrizes de ambos os analitos. / Atomic Absorption Spectrometry (AAS) is a robust analytical technique whose applications extend to many different analytes and matrices. Its limitation lies on the far UV region (~ 190 nm) and therefore it remained exclusive for metal determination as non-metals typically absorb within the vacuum-UV region. With the invention of the High-Resolution Continuum Source AAS (HR CS AAS), the AAS analysis has been upgraded and a new dimension (wavelength) was added: the visualization of the analytical lines vicinity. This new feature allowed improved spectral information, mainly related to the structured bands of diatomic molecules, giving rise to the HR CS Molecular Absorption Spectrometry (MAS). The goal of this thesis was the evaluation of new analytical procedures for non-metals determination by HR CS MAS, specifically Br, Cl, and S, using graphite furnace as the atomizer. Bromine in plastic electronic components was evaluated as CaBr after Soxhlet extraction with toluene. This method had limits of detection (LD) and quantification (LQ) of 4.3 and 14 -ng, respectively, using Pd as chemical modifier. Sulfur determination via CS molecule employed two distinct matrices: coal and diesel. Coal samples were prepared as a slurry with Triton X-100 0.04% m v1 for injection in the HR CS MAS and the external calibration employed was (NH4)2SO4as sulfur standard. The method LD and LQ were 0.01% m m1 and 0.05% m m1, respectively. Two methods were studied for diesel samples: (i) alcoholic emulsion with ethanol 50% v v1, with an LD of 0.12 g kg1 and an LQ of 0.40 g kg1, suitable for sulfur high concentration determination in diesel; and (ii) direct diesel injection in the HR CS MAS system, whose LD and LQ were 3 mg kg-1and 9 mg kg-1, respectively. Both methods employed Pd nanoparticles as chemical modifier, with better results for direct diesel analysis. Ultimately, a new concept was investigated in HR CS MAS: the isotopic shift of diatomic molecules. An absorption profile consisted of multiple peaks was due to vibrational and rotational energy couplings within the electronic transition observed by HR CS MAS, which provided the isotopic shift. This effect was detected on AlCl and CaBr molecules, whose target isotopes were, respectively, 35Cl &37Cl and 79Br &81Br. The observed isotopic shifts were 15.6 pm (AlCl) and 41.6 pm (CaBr) at the selected wavelengths, appropriate for isotopic dilution calibration, which featured LDs of 2.5 ng and 64 ng, respectively. Natural and mineral water samples were evaluated for Cl determination; and Br was found in PVC and tomato leaves samples, both introduced as solid samples in HR CS GFMAS. Isotopic dilution adequately corrected the spectral interferences derived from the matrices of both analytes.
23

Desenvolvimento de métodos analíticos para determinação de Ca, Mg, Na, K, S e P, em biodiesel, por espectrometria de absorção atômica e molecular de alta resolução e fonte contínua / Development of analytical methods for determination of Ca, Mg, Na, K, S and P, in biodiesel, by atomic absorption spectrometry and high-resolution continuum source molecular absorption spectrometry

Luís Eduardo Bernardes 09 March 2017 (has links)
O crescimento do consumo energético trouxe a necessidade do desenvolvimento de fontes alternativas de energia, uma vez que os combustíveis fósseis, além dos impactos ambientais, constituem uma fonte finita, cuja formação leva milhares de anos para ocorrer. Neste contexto, surge o biodiesel, uma fonte de energia renovável e que pode ser obtido através da reação de transesterificação dos triglicerídeos presentes em óleos vegetais e gorduras animais com álcoois de cadeia curta. Assim como os combustíveis derivados do petróleo, o biodiesel deve seguir alguns parâmetros de qualidade estabelecidos pela Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP). A estabilidade e a qualidade do biocombustível são afetadas por uma série de fatores, dentre os quais as concentrações de magnésio, cálcio, sódio, potássio, enxofre e fósforo. Visando unificar a determinação destes analitos através da espectrometria de absorção atômica e da espectrometria de absorção molecular de alta resolução e fonte contínua, foram propostos como métodos de preparo de amostra a digestão ácida e a fotodegradação para determinação de Mg, Ca, Na e K por FAAS, e análise direta para determinação de S e P por GF MAS. O preparo de amostra influenciou no limite de detecção dos elementos, visto que os melhores LOD para Na, K e Ca foram observados através da digestão ácida, especialmente na condição 2, empregando 6,0 mL de HNO3, 2,0 mL de H2O2 e 2,0 mL de HCl, enquanto que para Mg o menor LOD ocorreu para a fotodegradação por reação foto-Fenton. Os menores valores de RSD para Mg e Ca foram obtidos por fotodegradação foto-Fenton e por TiO2, respectivamente, e para Na e K por fotodegradação foto-Fenton e digestão ácida na condição 2, respectivamente. O biodiesel estava dentro das especificações exigidas pela legislação, então foram realizados testes de adição e recuperação para avaliar a exatidão dos métodos propostos. O Mg foi o analito cuja determinação apresentou as menores concentrações características, indicando maior sensibilidade, e também os menores LOD, enquanto que o cálcio apresentou a menor sensibilidade. A digestão ácida com 6,0 mL de HNO3 e 4,0 mL de H2O2 e a fotodegração foto-Fenton possibilitaram as melhores recuperações de analito considerando o conjunto dos 4 elementos, com variação de 88 % a 108 %. O padrão de enxofre a base de óleo mineral demonstrou não ser apropriado para a determinação de enxofre em biodiesel por análise direta. O uso de 2-mercaptoetanol como padrão, no entanto, possibilitou o estudo da molécula CS na amostra de biodiesel, apresentando-se mais compatível e com ganho de sensibilidade nas medidas. O emprego de Ir como modificador químico permanente e da mistura Pd/Mg permitiu boa estabilização da molécula CS, um LOD de 1,8 µg g-1 de biodiesel foi obtido, e a concentração de S na amostra não enriquecida foi de 6,2 µg g-1, abaixo do limite máximo permitido. Para o fósforo, somente foi possível obter sinal analítico em 246,40 nm, correspondente a uma transição rotacional da molécula PO, utilizando W como modificador químico. O LOD obtido foi de 2,2 µg g-1, e a concentração estimada na amostra pura pela curva de adição padrão estava entre o LOD e o LOQ calculados, abaixo do limite máximo permitido. Os métodos desenvolvidos mostraram-se apropriados para a determinação dos analitos na amostra de biodiesel via espectrometria de absorção atômica/molecular por chama e forno de grafite, atendendo a legislação vigente / The increase in the energy consumption over the last years led to the research and development of alternatives sources of energy, once the fossil fuels, besides their environmental effects, represent a finite source which takes thousands of years to be formed. In this context, biodiesel arises as a renewable source that can be produced by the transesterification reaction between triglycerides of vegetable oils or animal fat and short chain alcohols. As well as for oil-derived fuels, biodiesel must obey some quality specifications established by the National Petroleum, Natural Gas and Biofuel Agency (NPA). The stability and quality of biofuels are influenced by conditions such as the concentration of magnesium, calcium, sodium, potassium, sulfur and phosphorus. This study aims to unify the determination of these elements by atomic absorption spectrometry and high-resolution continuum source molecular absorption spectrometry techniques. The proposed methods of sample treatment are the acid digestion and the photodegradation for Mg, Ca, Na and K by FAAS, and the direct analysis for S and P by GF MAS. The limits of detection were influenced by the sample treatment. The lowest LOD values for Na, K and Ca were observed through acid digestion, especially second condition (6,0 mL of HNO3, 2,0 mL of H2O2 and 2,0 mL of HCl), while for Mg the lowest LOD was achieved by photo-Fenton photodegradation. The lowest RSD values for Mg and Ca were observed by photo-Fenton and TiO2 photodegradations, respectively, and for Na and K by photo-Fenton photodegradation and acid digestion (condition 2), respectively. The biodiesel sample was within the specifications legally required, therefore recovery tests were used to evaluate the accuracy of the proposed methods. Magnesium was the analyte whose determination showed the lowest characteristic concentrations, which indicates the best sensitivity, and also the lowest detection limits, while calcium was the least sensitive analyte. The acid digestion (6.0 mL of HNO3 and 4.0 mL of H2O2) and photodegradation by photo-Fenton reaction allowed the best recoveries, considering the set of 4 analytes, ranging from 88 % to 108 %. The oil-based standard was not appropriated for sulfur determination in biodiesel sample by direct analysis. The use of 2-mercaptoethanol as a standard led to a better sensitivity, in addition to the compatibility with the sample. Iridium as permanent chemical modifier, along with a mixture of Pd/Mg, provided good stabilization of CS molecule, a LOD of 1.8 µg g-1 was achieved, and the sulfur concentration in the biodiesel sample, obtained by standard addition method, was 6.2 µg g-1, below the limit legally established. Regarding phosphorus study for determination in biodiesel, an acceptable analytic signal was obtained at 246.40 nm, which corresponds to a rotational transition of PO molecule. The calculated LOD was 2.2 µg g-1, and the estimated concentration in the pure sample, obtained by a standard addition curve, was between the LOD and LOQ, below the limit legally established. The developed methods were appropriated for determination of the proposed analytes set in biodiesel sample by atomic/molecular absorption spectrometry, in agreement with current legislation
24

Rings Characterized by Direct Sums of CS Modules

Er, Noyan Fevzi 21 November 2003 (has links)
No description available.
25

Podnikatelský plán společnosti Web Software Consulting [cs]

Kyjovská, Gabriela January 2007 (has links)
Diplomová práce je zaměřena v oblasti teorie na charakteristiku malých a středních firem včetně jejich právních forem, na teorii sestavení podnikatelského plánu a na možné zdroje financování podnikatelského plánu. Praktická část se věnuje sestavení konkrétního plánu společnosti Web Software Consulting. Tato práce slouží pro posouzení reálnosti a životaschopnosti podnikatelského nápadu.[cs]
26

Suporte para a criatividade musical cotidiana : mixDroid Segunda Geração / Support for everyday musical creativity : mixDroid Second Generation

Farias, Flávio Miranda de January 2015 (has links)
Atualmente é comum ver jovens e adultos utilizando das novas tecnologias digitais para atividades musicais como entretenimento. No entanto, a maioria limita-se somente ao papel de ouvinte, munidos de seus players de som, dificilmente ousando criar suas próprias composições ou sons, às vezes pelo custo de aplicações pagas, outras vezes pela complexidade inerente a aplicações voltadas a músicos. Esta pesquisa foi focada em simplificar a prática musical voltada ao público leigo e descompromissado. Quando se trata de software voltado a este nicho, não existem muitos disponíveis. Neste trabalho utilizamos conceitos e técnicas da Música Ubíqua para preencher esta lacuna: foi desenvolvido o protótipo mixDroid 2G CS, que propicia recursos para criação de mixagens em dispositivos móveis. Com este protótipo foram realizados testes com alunos de uma instituição de nível técnico em informática, utilizando equipamentos portáteis como celulares e tabletes Android. Neste volume, serão apresentados conceitos e definições técnicas do mixDroid 2G CS, assim como dois experimentos com usuários reais. Com base nos resultados dos experimentos, analisamos as implicações dos perfis dos produtos criativos e o desempenho dos sujeitos e indicamos as limitações e as perspectivas abertas para seu uso em atividades criativas, discutindo a sua viabilidade e possíveis aplicações futuras. / Nowadays, it is common to see young people and adults using new digital technologies for music production as entertainment. However, most people are only listeners, hardly ever daring to create their own compositions or sounds because of the cost and the complexity of the programs targeted for musicians. The purpose of this research is to simplify music production for the public without musical experience. In this study, we used concepts and techniques of Ubiquitous Music to solve various problems: a prototype software called mixDroid 2G CS was developed, which uses a new interaction metaphor for mixing sonic content on mobile devices. Tests were conducted with students of an institution devoted to technical courses in computer science. Targeting the use of portable devices, the Android system was used on a variety of cell phones and tablets. In this volume, I will present concepts and the technical description of mixDroid 2G CS, including two experiments with real users. Based on the results of the experiments, I analyzed the implications of the creative's products profiles and the subjects' performance during the tasks, and indicated the limitations and perspectives for its use in creative activities, discussing the feasibility of its application in future projects.
27

Association Behavior of Biotinylated and Non-Biotinylated PolyEthylene Oxide-b-Poly(2-(Diethylamino)Ethyl Methacrylate)

Tan, J. F., Ravi, P., Too, Heng-Phon, Hatton, T. Alan, Tam, K. C. 01 1900 (has links)
Biotinylated and non-biotinylated copolymers of ethylene oxide (EO) and 2-(diethylamino)ethyl methacrylate (DEAEMA) were synthesized by the atom transfer radical polymerization technique (ATRP). The chemical compositions of the copolymers as determined by NMR are represented by PEO₁₁₃PDEAEMA₇₀ and biotin-PEO₁₀₄PDEAEMA₉₃ respectively. The aggregation behavior of these polymers in aqueous solutions at different pHs and ionic strengths was studied using a combination of potentiometric titration, dynamic light scattering (DLS), static light scattering (SLS), and transmission electron microscopy (TEM). Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers form micelles at high pH with hydrodynamic radii (Rh) of about 19 and 23 nm, respectively. At low pH, the copolymers are dispersed as unimers in solution with Rh of about 6-7 nm. However, at a physiological salt concentration (cs) of about 0.16M NaCl and a pH of 7-8, the copolymers form large loosely packed Guassian chains, which were not present at the low cs of 0.001M NaCl. The critical micelle concentrations (CMC) and the cytotoxicity of the copolymers were investigated to determine a suitable polymer concentration range for future biological applications. Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers possess identical CMC values of about 0.0023 mg/g, while the cytotoxicity test indicated that the copolymers are not toxic up to 0.05mg/g (> 83% cell survival at this concentration). / Singapore-MIT Alliance (SMA)
28

In situ measurements of radionuclide concentration in soil : An investigation into detector properties and methods

Kastlander, Johan January 2010 (has links)
In case of a release of radioactive nuclides into the environment it is necessary to  have reliable methods to estimate the potential effect on people and the ecosystem. In this context the total activity deposited, the elemental composition and the depth distribution are of importance. An efficient in situ method to estimate the average contamination over larger areas using high purity germanium (HPGe) detectors has been developed. The method combines simulation of photon transport with measured detector properties. The total activity of 137Cs determined from gamma-ray spectra recorded in situ are compared to results from soil sampling. Another in situ method has been developed to determine the depth distribution of a radionuclide contamination, using an array of small detectors inserted into the ground, as an alternative to the standard procedure of soil sampling. The possibility to use cadmium telluride (CdTe) detectors as well as lanthanum bromide (LaBr3) detectors has been investigated. As a demonstration of the developed method the small-scale variation of the activity distributions in an area covering 350 m2 have been measured and is compared to results obtained by other methods. / At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.
29

Compressed Sampling for High Frequency Receivers Applications

bi, xiaofei January 2011 (has links)
In digital signal processing field, for recovering the signal without distortion, Shannon sampling theory must be fulfilled in the traditional signal sampling. However, in some practical applications, it is becoming an obstacle because of the dramatic increase of the costs due to increased volume of the storage and transmission as a function of frequency for sampling. Therefore, how to reduce the number of the sampling in analog to digital conversion (ADC) for wideband and how to compress the large data effectively has been becoming major subject for study. Recently, a novel technique, so-called “compressed sampling”, abbreviated as CS, has been proposed to solve the problem. This method will capture and represent compressible signals at a sampling rate significantly lower than the Nyquist rate.   This paper not only surveys the theory of compressed sampling, but also simulates the CS with the software Matlab. The error between the recovered signal and original signal for simulation is around -200dB. The attempts were made to apply CS. The error between the recovered signal and original one for experiment is around -40 dB which means the CS is realized in a certain extent. Furthermore, some related applications and the suggestions of the further work are discussed.
30

Clinical, functional, and genetic analysis of NER defective patients and characterization of five novel XPG mutations

Schäfer, Annika 14 August 2012 (has links)
No description available.

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