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Extension of thermodynamic insights on batch extractive distillation to continuous operation / Conception des procédés de distillation extractive continue basée sur des critères de faisabilité thermodynamique de la distillation extractive discontinueShen, Weifeng 21 September 2012 (has links)
Nous étudions la faisabilité du procédé de distillation extractive continue pour séparer des mélanges azéotropiques A-B à température de bulle minimale ou maximale, avec un tiers corps E lourd ou léger. Les mélanges ternaires A-B-E appartiennent aux classes 1.0-1-a et 1.0-2 qui se subdivisent chacune en deux souscas selon la position de la courbe d'univolatilité. La colonne de distillation a trois sections, rectification, extractive, épuisement. Nous établissons les équations décrivant les profiles de composition liquide dans chaque section en fonction des paramètres opératoires: pureté et taux de récupération du distillat, taux de reflux ratio R et rapport des débits d'alimentation FE/F dans le cas d'un tiers corps lourd ; pureté et taux de récupération du produit de pied, taux de rebouillage S et rapport des débits d'alimentation FE/F dans le cas d'un tiers corps léger. Avec un tiers corps lourd alimenté comme liquide bouillant au dessus de l'étage d'alimentation du mélange A-B, nous identifions le distillat atteignable et les plages de valeurs faisables des paramètres R et FE/F à partir du critère général de faisabilité énoncé par Rodriguez-Donis et al. (Ind. Eng. Chem. Res, 2009, 48(7), 3544–3559). Pour la classe 1.0-1a, il existe des rapport FE/F et reflux ratio minimum. Le rapport FE/F est plus important pour le procédé continu que pour le procédé discontinu parce que la faisabilité du procédé continu nécessite que les profils d'épuisement et extractifs s'intersectent. Pour la classe 1.0-2, les deux constituants A et B sont des distillats potentiels, l'un sous réserve que le rapport FE/F reste inférieur à une valeur limite maximale. Le procédé continu exhibe également une valeur minimale de FE/F à un taux de reflux ratio donné, contrairement au procédé discontinu. Avec un tiers corps léger alimenté comme vapeur saturante sous l'étage d'alimentation du mélange A-B, nous identifions le produit de pied atteignable et les plages de valeurs faisables des paramètres S et FE/F à partir du critère général de faisabilité énoncé par Rodriguez-Donis et al. (Ind. Eng. Chem. Res, 2012, 51, 4643–4660). Comparé au cas des tiers corps lourds, le produit principal est obtenu en pied. Autrement, les comportements des classes 1.0-1a et 1.0-2 sont analogues entre les tiers corps léger et lourd. Avec un tiers corps léger, le procédé continu ajoute la contrainte que les profils de rectification et extractifs s'intersectent. La contrainte d'intersection des profils d'épuisement et extractif est partagée par les deux modes opératoires continu et discontinu. Ce travail valide la méthodologie proposée pour évaluer la faisabilité du procédé de distillation extractive continue et permet de comparer les tiers entre eux en termes de taux de reflux ratio minimum et de rapport de débit d'alimentation minimal / We study the continuous extractive distillation of minimum and maximum boiling azeotropic mixtures A-B with a heavy or a light entrainer E, intending to assess its feasibility based on thermodynamic insights. The ternary mixtures belong to the common 1.0-1a and 1.0-2 class ternary diagrams, each with two sub-cases depending on the univolatility line location. The column has three sections, rectifying, extractive and stripping. Differential equations are derived for each section composition, depending on operating parameters: distillate product purity and recovery, reflux ratio R and entrainer – feed flow rate ratio FE/F for the heavy case; bottom product purity and recovery, reboil ratio and entrainer – feed flow rate ratio for the light entrainer case. For the case with a heavy entrainer fed as a boiling liquid above the main feed, the feasible product and operating parameters R and FE/F ranges are assessed under infinite reflux ratio conditions by using the general feasibility criterion enounced by Rodriguez-Donis et al. (Ind. Eng. Chem. Res, 2009, 48(7), 3544–3559). For the 1.0-1a class, there exists a minimum entrainer - feed flow rate ratio to recover the product, and also a minimum reflux ratio. The minimum entrainer - feed flow rate ratio is higher for the continuous process than for the batch because of the additional requirement in continuous mode that the stripping profile intersects with the extractive profile. For the 1.0-2 class both A and B can be distillated. For one of them there exists a maximum entrainer - feed flow rate ratio. The continuous process also has a minimum entrainer - feed flow rate ratio limit for a given feasible reflux ratio. For the case with a light entrainer fed as saturated vapor below the main feed, the feasible product and operating parameters S and FE/F ranges are assessed under infinite reflux ratio conditions by using the general feasibility criterion enounced by Rodriguez-Donis et al. (Ind. Eng. Chem. Res, 2012, 51, 4643–4660), Compared to the heavy entrainer case, the main product is removed from the column bottom. Similar results are obtained for the 1.0-1a and 1.0-2 class mixtures whether the entrainer is light or heavy. With a light entrainer, the batch insight about the process feasibility holds for the stripping and extractive sections. Now, an additional constraint in continuous mode comes from the necessary intersection between the rectifying and the extractive sections. This work validates the proposed methodology for assessing the feasibility of continuous extractive distillation processes and enables to compare entrainers in terms of minimum reflux ratio and minimum entrainer feed flow rate ratio
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Hedge Effectiveness in Copper Futures Market: Case study for "Erdenet" Mining Co.Ltd in Mongolia / Hedge Effectiveness in Copper Futures Market: Case study for "Erdenet" Mining Co.Ltd in MongoliaKhurelbaatar, Baigali January 2015 (has links)
The objective of the thesis is to analyze the copper futures market in London Metal Exchange (LME) and to recommend appropriate hedging strategy in copper futures market to the Erdenet Mining Corporation in Mongolia. It uses daily official settlement copper prices of LME in the spot and 3 month futures markets from 2000-2014. Initially, we use cointegration test and ECM to investigate the copper market efficiency. Then OLS, ECM, GARCH, EGARCH and ECM-GARCH models are employed to compute different optimum hedge ratios. Finally, the hedge effectiveness is measured based on minimization of the value of AIC and SBIC. Our result indicate that copper futures market is inefficient. Hedge effectiveness comparison concludes that ECM model gives the best hedging performance. However, ECM-GARCH is accounted to be the best model for hedging strategy since it captures the time-varying conditional heteroscedasticity to ECM model. Powered by TCPDF (www.tcpdf.org)
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Finanční analýza podniku/Financial Analysis of an Enterprise / Financial Analysis of an EnterpriseDrobná, Michaela January 2010 (has links)
This graduation thesis deal with the financial analysis of the company. Is elaborated for the needs of the owner and creditor of the company. Financial analysis covers the period basis of time 2006 - 2009. To assess the financial situation I use standard methods mentioned in the theoretical part.
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Vazba jako prostředek ultima ratio / Criminal custody as an ultima ratio instrumentNekolová, Petra January 2019 (has links)
Criminal custody as an ultima ratio instrument This thesis deals with a criminal custody which is considered as the most serious instrument within criminal procedural security measures which should be used by law enforcement authorities only in the most extreme cases when all of the legal conditions are strictly fulfilled. One of the purposes of this thesis is to explicate, through personal freedom and presumption of innocence both guaranteed by the Czech Constitution and both significantly affected by custody, the importance of using this instrument only in situations without any other solution when is impossible to reach the purpose of criminal proceedings by using some of the more lenient measures, it means to use the custody just as an ultima ratio instrument. A crucial part of this thesis pays attention to the individual legal conditions of current effective legislation that should ensure observance of this principle also in practice. In the mentioned part the procedure of the authorities deciding on custody is analysed in detail that authorities firstly must resolve the question if the prosecution of a specific person is justified and if a certain specific degree of suspicion is achieved proving that this one perpetrated an offence. After that is necessary to investigate the existence of...
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EFFECT OF ROTATIONAL RESTRAINTS ON THERMAL POST BUCKLING RESPONSE OF SWAY COLUMNSRegmi, Kamal 01 May 2019 (has links)
The objective of this study is to examine the effect of rotational restraints on thermal post-buckling response of sway columns using geometrically nonlinear analysis. The present design approach considers columns to have failed once they buckle. However, the columns under fire load are found to exhibit significant post-buckling strength which could be utilized for more economical design. The past researchers on the nonlinear thermal analysis used isolated columns with idealized support conditions which mean the columns are assumed to be free or fully restrained in the rotation, lateral and, axial directions. However, that is seldom the case in real structures and the restraint at an end of the column depends upon the members connected at that joint. The restraint provided to the column by the members connected at the joint will be in between the free case and fully restrained case. This study incorporates the variation in rotational restraint due to changes in the properties of members connected at the ends of the column. The columns are assumed to be fully restrained in the axial direction. Since the study is being carried out on sway columns, the restraint in the lateral direction is zero.
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Development of an automated system for the measurement of focal ratio degradation of high numerical aperture fibresLee, Jooyoung 07 August 2019 (has links)
The thesis presents the development and testing of an automated fibre optic test system for the measurement of focal ratio degradation (FRD) in high numerical aperture fibres. In particular, the fibres under examination are being proposed for use in the Maunakea Spectroscopic Explorer (MSE), a new telescope currently being designed for wide-field surveys of the night sky. A critical subsystem of the MSE is the Fiber Transmission System (FiTS) that connects the focal plane to the telescope’s spectrographs. In preparation for MSE-FiTS, a method of characterizing the focal ratio degradation (FRD), between the input and output of every fibre, of candidate multi-mode fibres is highly important. The ultimate goal is the testing of all 4,332 fibres after assembly and prior to installation on MSE. An optical bench has been constructed to test the performance of an automated characterization system; a variation on the collimated beam test. Herein we present the underlying analysis FRD measurement method, the optical design of the test bench, the motion control system and the software for measuring FRD, and controlling the automated test system. The open-source automation software is also introduced; the Big FiTS Fibre Wrapper (Big FFW). The results of tests performed using the Big FFW on samples of candidate fibres are presented and compared with the results in the literature using manual methods. The results suggest that the candidate MSE fibre meets the science requirement of less than 5% focal ratio degradation for an f/2 input beam measured at the fibre output. There is less than 1% disagreement between the automated measurement method and manual methods reported in the literature. The fully automated system can measure the FRD of up to 10 fibres in a typical MSE fibre bundle configuration. / Graduate
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Noncompaction of the ventricular myocardium: factors associated with the compaction ratio in congenital and acquired paediatric cardiac diseaseHunter, Vivienne Isla 17 November 2009 (has links)
M.Sc. (Med. (Paediatric Cardiology)), Faculty of Health Sciences, University of the Witwatersrand, 2008 / Left ventricular (LV) noncompaction is characterized by the presence of an
extensive trabecular myocardial layer within the luminal aspect of the compact
myocardium of the ventricular wall. The trabeculae are both excessive in number and
more prominent than normal. Noncompaction may occur in isolation usually with
clinical features of dilated cardiomyopathy, or it may be associated with congenital or
acquired heart diseases. Echocardiography is the reference standard for diagnosis,
where a ratio of thickness of trabecular-to-compact myocardium (compaction ratio) of
>2 is a major diagnostic criterion. Noncompaction is usually considered to result from
persistence of the highly trabeculated myocardium found in early cardiogenesis of
the human embryo. If persistence of excess trabeculae is the only determinant of the
compaction ratio it would be expected that it would remain a consistent measurement
in postnatal life. However, temporal changes in the degree of noncompaction in
individual case reports have raised the question as to whether the compaction ratio
might be sensitive to haemodynamic or other factors.
In the present dissertation, I assessed echocardiographically whether the
compaction ratio is associated with increases in indices of LV volume preload in 100
children or adolescents with ventricular septal defects (VSD), and 36 with chronic
rheumatic heart disease (RHD). Compared to 79 normal controls (compaction
ratio=1.4±0.07), patients with VSDs (compaction ratio=2.0±0.2, p<0.0001) and RHD
(compaction ratio = 2.0±0.3, p< 0.0001) had a marked increase in the compaction
ratio. A compaction ratio>2 was found in 42% of patients with VSDs and 47% with
RHD. In VSDs, independent of age and gender, the compaction ratio was positively
associated with LV mass index (LVMI) (partial r=0.44, p<0.0001), VSD size (partial
r=0.4, p<0.0001), LV end diastolic diameter indexed (LVEDD) (partial r=0.24, p=
0.01), and the presence of additional shunts (partial r=0.21, p=0.02). In RHD,
independent of age and gender, the compaction ratio was positively
associated with LVEDD (partial r=0.62, p=0.0001), and LVMI (partial r=0.48,
p=0.005), and negatively with LV ejection fraction (partial r=0.31, p=0.03).
The strong association of indices of LV volume load and the compaction ratio
would suggest that haemodynamic influences are contributing to the compaction ratio
both in congenital and acquired cardiac disease in childhood. Thus an increased
compaction ratio may be the consequence of an increased volume preload, and
therefore may not necessarily occur only as a result of persistence of embryonic
patterns.
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Balanço de energia, consumo hídrico e coeficiente de cultivo do trigo no sudeste brasileiro / Energy balance, water consumption and crop coefficient of wheat in the southeastern BrazilPereira, Rodolfo Armando de Almeida 29 June 2018 (has links)
O trigo é uma importante cultura agrícola no mundo, sendo uma das poucas na qual o Brasil não é autossuficiente, produzindo apenas cerca de 50% da sua demanda interna. Estudos relacionados ao crescimento da cultura e suas trocas de massa e energia com a atmosfera podem auxiliar no planejamento e manejo da cultura. O objetivo desse trabalho foi estudar o balanço de energia, o consumo hídrico e a recomendação de valores de Kc, com enfoque no acoplamento copa-atmosfera. Para isso foi instalado um experimento na Escola Superior Luiz de Queiroz- ESALQ, semeado no dia 30 de maio de 2017 sob sistema de irrigação. Os resultados indicam que o fluxo de calor latente (LE), calor sensível (H) e calor no solo (G) representaram 81,17 %,14,13% e 4,7% do saldo de radiação (Rn). A evapotranspiração acumulada para a cultura do trigo foi de 301 mm, tendo uma evapotranspiração média diária de 2,8 mm.d-1. A cultura teve um fator de desacoplamento (Ω) médio para o ciclo de 0,53, porém variou em relação as fases fenológicas: 0,68 (emborrachamento), 0,55 (floração), 0,26 (formação de grãos) e 0,3 (maturação). O coeficiente de cultura ao longo do ciclo foi 0,58, 1,12, 1,46, 1,23, 1,32 e 0,73 para as fases de estabelecimento, perfilhamento, emborrachamento, floração, formação de grão e maturação, e o valor médio para todo o ciclo foi de 1,08. Os valores de Kc indicaram uma queda quando houve elevação da evapotranspiração de referência (ETo). Assim os valores de Kc para diferentes intervalos de ETo foram: 1,09 (ETo ≤ 2); 1,34 (2< ETo ≤ 3); 1,25 (3 < ETo ≤ 4); 0,77 (ETo > 4). / The wheat is one of the most important crop of the world, and the few one that Brazil is not self-sufficient, producing only 50% of domestic demand. Studies related crop growth and its mass and energy exchange with atmosphere may help to improve the crop planning and management. The objective here was to study on the energy balance and water use of wheat crop, take into account the canopy-atmosphere coupling approach in such study. To do so, an irrigated experiment was conducted in Piracicaba-SP, at the Escola Superior Luiz de Queiroz-ESALQ, sown on May of 2017. The results showed that the latent heat flux (LE), sensible heat (H) and soil heat (G) represented 81.17%, 14.13% and 4.7% of the net radiation (Rn). Cumulative evapotranspiration for the whole wheat crop was 301 mm, with na average daily evapotranspiration of 2.8 mm.d-1. The crop had a mean decoupling fator (Ω) for the cycle of 0.53, but varied with the phenological phases as: 0.68 (head development), 0.55 (flowering), 0.26 (grain formation) and 0.3 (maturation). The crop coefficient along the cycle was 0.58, 1.12, 1.46, 1.23, 1.32 and 0.73 for the respective phases establishment, tillering, head development, flowering, grain formation and maturation, with the average Kc for the cycle was 1.08. The values of Kc indicated a decrease when there was elevation of reference evapotranspiration (ETo). Thus, Kc values for different ETo intervals were: 1.09 (ETo ≤ 2); 1.34 (2 < ETo ≤ 3); 1.25 (3 < ETo ≤ 4); 0.77 (ETo > 4).
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Transformações em dados composicionais para a aplicação da análise de componentes principais / Transformations in compositional data for application of principal components analysisMessias, Ricardo Matioli 29 April 2016 (has links)
A análise de dados composicionais está sendo amplamente utilizada nas diversas áreas do conhecimento como por exemplo na análise de sedimentos rochosos, na comparação de diferentes células e até na análise criminalística na comparação de evidências de crimes. Durante a história da análise deste tipo de dados existiram muitos tipos de ajustes utilizados para contornar o problema da soma constante das variáveis e ainda hoje não temos um consenso de qual a melhor solução a ser utilizada. Neste trabalho, temos como objetivo a enunciação das 7 transformações que mais foram utilizadas ao longo do tempo e suas vantagens e desvantagens. A análise de componentes principais foi escolhida para o comparativo destas transformações. Fizemos a aplicação destas transformações em três bancos de dados reais com características diferentes entre si, comparamos os resultados e analisamos qual das transformações apresentou o melhor desempenho em cada base de dados. Os critérios de comparação foram o percentual da variância explicada, as variáveis que foram mais importantes para a primeira componente principal, cargas das variáveis nas componentes principais mais importantes assim como suas correlações com as variáveis. Também, simulamos quatro estruturas de bases de dados composicionais para avaliar o desempenho das transformações. Para essas comparações e simulações, foram desenvolvidas algumas funções, utilizando o \\textit estatístico R, que visam facilitar a comparação entre as sete transformações, assim auxiliando na escolha de qual das transformações melhor se adapta aos dados. Pelos resultados obtidos notamos que: nas bases de dados reais, os resultados das explicações da variância das transformações são similares e as transformações Ref e Alr mostram melhores desempenhos que as demais; nas quatro estruturas simuladas as transformações Ref e Alr também possuem os melhores resultados na explicação da variância e a interpretação de suas componentes principais são parecidas, assim como as transformações Trad, Log e Clr. Com isso notamos que independentemente da aplicação do logaritmo nas transformações Alr e Log elas apresentaram resultados muitos similares às transformações Ref e Trad, respectivamente, tanto na explicação da variância como na interpretação das componentes principais. / The compositional data analysis is being widely used in several areas of knowledge such as the analysis of rocky sediments, to compare different biological cells and even in forensic analysis to compare crimes evidences. During the history of the analysis of such data, to circumvent the problem of variable\'s constant sum were used many types of adjustments. Until now, we do not have a consensus in which is the best solution to be used in this cases. In this paper, we aim to enunciate seven transformations that most were used over time and their advantages and disadvantages. The principal component analysis was chosen for the comparison of these transformations. We applied this transformations in three real databases with different characteristics, we hope to compare the results and analyze which transformation have the best performance in each database. The comparison criteria were the percentage of explained variance, the variables that were most important to the first principal component,variable\'s loads in the most important principal components as well their correlation with the variables. We also simulated four compositional data bases structures to evaluate the performance of the transformations. For these comparisons and simulations were developed some functions, using the statistical software R, to facilitate comparison between the seven transformations, thus assisting in choosing which of the best transformation fits to the data. From the results we note that: for the real databases, the results of the variance explanation of all transformations are similar, thus Ref and Alr transformations show better performances than the others; in the four simulated structures the Ref and Alr transformations also have the best results in the variance explanation and interpretation of its main components are similar, as well as the transformations Trad, Log and Clr. Thus we note that independently of applying logarithm in and Log and Alr transformations they present very similar results as Ref and Trad transformations, respectively, both in variance explanation and in the interpretation of the principal components.
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The cross-sectional relationship between the fundamental variables and returns of Hang Seng Index constituent stocks of Hong Kong stock market.January 1996 (has links)
by Ho Man Shing, William. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 41-42). / ABSTRACT --- p.i / TABLE OF CONTENTS --- p.iii / LIST OF FIGURE --- p.v / LIST OF TABLES --- p.v / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Objectives of Research Project --- p.2 / Chapter II. --- LITERATURE REVIEW --- p.4 / Research work in the U. S --- p.4 / Research work in Japan and H. K --- p.5 / Chapter III. --- METHODOLOGY --- p.7 / Research design --- p.9 / Formation of portfolios --- p.10 / Univariate Analysis --- p.11 / Regression Analysis --- p.11 / Data collection --- p.12 / Chapter IV. --- RESULTS --- p.13 / Univariate analysis of returns and fundamental variables --- p.13 / Regression analysis of returns and fimdamental variables --- p.17 / Security level regression analysis of returns and fimdamental variables --- p.17 / Portfolio level regression analysis of returns and fundamental variables (ranked by different fundamental variables) --- p.21 / Portfolio level regression analysis of returns and fundamental variables (ranked by two different fundamental variables) --- p.27 / Effects of order of agglomeration and different combinations --- p.30 / Chapter V. --- SUMMARY AND CONCLUDING REMARKS --- p.37 / BIBLIOGRAPHY --- p.41 / APPENDICES / Chapter A --- List of Hang Seng Index Constituent Stocks during 1989 to1994 / Chapter B --- Print-out of the Regression Results at Security Level / Chapter C --- Print-out of the Regression Results at Portfolio Level (E/P then LS) / Chapter D --- Print-out of the Regression Results at Portfolio Level (LS then E/P)
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