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Qualidade pós-colheita de colmos de cana armazenados e seus reflexos na produção de cachaça / Quality of post-harvest stored cane stalks and its effects on the production of cachaçaJosé Humberto de Oliveira Filho 19 November 2015 (has links)
O armazenamento dos colmos de cana pode comprometer a manutenção do seu estado fisiológico, refletindo em consideráveis alterações na qualidade do caldo. Esta pesquisa teve como objetivos, avaliar as características tecnológicas e microbiológicas do caldo de cana colhida e armazenada, assim como seus reflexos na condução dos processos fermentativos e formação dos compostos químicos da cachaça. Após colheita da cana-de-açúcar, os colmos foram armazenados a temperatura ambiente (20 - 32°C) por períodos de 0, 24, 48, 72 e 96 horas, sendo o mosto preparado após extração do caldo. As fermentações foram conduzidas em processo batelada com reciclo de células, durante cinco ciclos fermentativos. O monitoramento da fermentação foi realizado através da quantificação de micro-organismos em atividade no processo e no fermento reciclado. Ao término das fermentações, foram analisadas as características tecnológicas dos vinhos, os quais foram destilados em alambique de cobre para quantificação dos compostos secundários (ácido acético, aldeído, álcoois superiores, ésteres e furfural) e contaminantes (álcool metílico, cobre e carbamato de etila) da cachaça. O armazenamento dos colmos de cana por períodos superiores a 48 horas causou significantes perdas na qualidade do caldo, reduzindo o conteúdo de sacarose, pureza e açúcares redutores totais, aumentando os níveis de acidez total, açúcares redutores e bactérias láticas. Os colmos de cana armazenados por 72 e 96 horas, afetou a condução do processo fermentativo, ocasionando decréscimo na viabilidade de células e brotos de leveduras, e elevação nas concentrações de bactérias láticas e leveduras não-Saccharomyces no fermento reciclado. As características tecnológicas dos vinhos também foram comprometidas com a utilização de colmos armazenados. Os níveis de acidez volátil, acetato de etila, acetaldeído, álcool metílico, cobre e carbamato de etila das cachaças apresentaram-se dentro do estabelecido pela Legislação Brasileira, enquanto o conteúdo de álcoois superiores e furfural foram superiores em destilados de cana colhida e armazenada. As concentrações de acetato de etila e carbamato de etila permaneceram elevadas ao final do 5º ciclo para destilados de colmos armazenados por períodos superiores a 48 horas, porém não excederam os limites especificados na Legislação. / The cane stalks storage can compromise the maintenance of their physiological state, resulting in considerable changes in the quality of the juice. This research aimed to evaluate the sugarcane juice technological and microbiological characteristics when harvested and stored, as well its reflexes in the cachaça fermentative processes and secondary compounds guiding processes. After harvested, the sugarcane stalks were stored at environmental temperature (20 - 32°C) at 0, 24, 48, 72, and 96 hours, preparing the must just before the juice extraction. Fermentations were carried out through the batch process, using five fermentative cycles. Monitoring the fermentation was carried out by quantifying microorganisms active in the process and recycled yeast. At the end of fermentation, the technological characteristics of the wines were analyzed, which was distilled in copper still for quantification of secondary compounds (acetic acid, aldehyde, higher alcohols, esters and furfural) and contaminants (methyl alcohol, copper and ethyl carbamate) of cachaça. The cane stalks storage for periods exceeding 48 hours caused significant losses in the juice technological quality, reducing the sucrose content, purity and total reducing sugars, increasing the acidity levels, reducing sugars and lactic acid bacteria. The cane stalks stored for 72 and 96 hours, influencing negatively the fermentative process; presenting decreasing in the viability of the yeast cells and shoots, as well an elevation in the lactic bacteria and non-Saccharomyces yeasts concentration in the recycled yeast. The technical characteristics of the wines were also compromised with the use of stalks stored. The volatile acidity levels, ethyl acetate, acetaldehyde, methanol, copper, and ethyl carbamate in the cachaças were within the ones established by the Brazilian law, while the superior alcohols and furfural content were high in the sugarcane distillated after harvested and stored. The concentrations of ethyl acetate and ethyl carbamate remained high at the end of the 5th cycle to cane spirits stored for longer than 48 hours, but did not exceed the limits specified in legislation.
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Avaliação dos parâmetros térmicos e calorimétricos das matérias-primas lipídicas e dos respectivos biodieseis produzidos / Evaluation of thermal and calorimetric parameters of lipid raw materials and their biodiesels producedOliveira, Levi Ezequiel de 25 November 2014 (has links)
O Brasil destaca-se em relação ao uso de fontes renováveis de energia com 41 % da matriz energética (biomassa e hidráulica) contra apenas 13% da média mundial. Desta forma, o país tem uma excelente oportunidade para desenvolver e aperfeiçoar novas matrizes energéticas associadas à produção de combustíveis através de fontes renováveis e que emitam baixa quantidade de dióxido de carbono um dos principais responsáveis pelo efeito estufa. No Brasil, a utilização do biodiesel se torna ainda mais relevante uma vez que a matriz do transporte brasileiro é predominantemente rodoviária (58%) na frente do ferroviário que vem em seguida com apenas 25%. Ainda vale destacar a enorme frota de caminhões no Brasil. Dentre os combustíveis mais consumidos destaca-se o diesel 39%, na frente da gasolina utilizada pelos automóveis com apenas 15% em relação ao consumo total de todos os combustíveis líquidos utilizados no Brasil. Portanto, torna-se estratégico para o país investir em programas de incentivo na produção, bem como em pesquisas para o desenvolvimento de processos de menor custo para a produção do biodiesel. O principal objetivo desse trabalho é avaliar parâmetros importantes de diferentes matérias-primas lipídicas e biodieseis, analisando a estabilidade térmica e oxidativa, poder calorífico e número de cetano. Todos esses parâmetros visam estudar a qualidade de diferentes biodieseis que poderão ser utilizados em motores do ciclo Diesel. Para análise da estabilidade térmica e oxidativa foram utilizadas as técnicas termoanalíticas termogravimetria (TGA) e a calorimetria exploratória diferencial (DSC) que são técnicas que trazem resultados bastante precisos e necessitam de pouca quantidade de amostra. Para o estudo do poder calorífico foi utilizada a calorimetria de combustão e para o estudo do número de cetano através de espectroscopia de infravermelho por Transforma de Fourier. Verificou-se que as composições de diferentes ácidos graxos constituintes da matéria-prima influenciam nessas propriedades. O óleo de babaçu se mostrou ser a melhor matéria-prima apresentando melhor estabilidade oxidativa e com menor gasto energético para produção de biodiesel por craqueamento térmico devido a grandes quantidades de ácidos graxos de cadeias curtas. O biodiesel de Tilápia etílico seguido do biodiesel de soja etílico apresentou as melhores estabilidades termo-oxidativa, índice de cetano e poder calorífico devido à grande quantidade de ésteres etílicos de cadeias longas. O estudo de blendas de biodiesel com diesel mineral mostrou que quanto maior a quantidade de biodiesel na blenda melhor a estabilidade térmica, número de cetano e índice de cetano. Porém, essa tendência se inverte em relação ao poder calorífico que diminue com a adição de biodiesel na blenda. / The Brazil walks to be an example regarding the use of renewable energy sources to 41% of energy sources (biomass and hydro) only 13% of the world average. Thus, the country has an excellent opportunity to develop and refine new energy matrices associated with the production of fuels from renewable sources that emit low amounts of carbon dioxide a major greenhouse. In Brazil, the use of biodiesel becomes even more relevant since the matrix of the Brazilian road transport is predominantly (58%) in superior of the railway\'s next with only 25%. Yet it is worth noting the huge fleet of trucks in Brazil. Among the most consumed fuel highlights the diesel 39%, ahead of the gasoline used by cars with only 15% in the total consumption of all liquid fuels used in Brazil. Therefore, is strategic for the countries invest in incentive programs in production as well as in research for the development of lower-cost processes for the production of biodiesel. The main objective of this work is to evaluate important parameters of different raw materials and lipid biodiesels, analyzing thermal and oxidative stability, calorific value and cetane number. All these parameters are aimed at studying the quality of different biodiesels that could be used in Diesel cycle engines. To analyze the thermal and oxidative stability, the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques that is bringing quite accurate results and requires little amount of sample was used. To study the calorific value and combustion calorimetry for the study of cetane number by Fourier transform spectrometer was used. It has been found that the compositions of different constituent fatty acids of the raw material influence these properties. The babassu oil proved to be the best raw material showing better oxidative stability and lower energy consumption for biodiesel production by thermal cracking by having large amounts of short chain fatty acids. Biodiesel Tilapia followed by ethyl biodiesel ethyl soybeans had the best thermo-oxidative stability, cetane number and calorific value due to the large amount of ethyl esters of long chains. The study of blends of biodiesel with mineral diesel fuel showed that the greater the amount of biodiesel in the blend better thermal stability, cetane number and cetane index. However, this trend is reversed in relation to the calorific value only decreases with the addition of biodiesel in the blend.
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Jämförelse av ekonomiskt utfall vid klassning av massaved enligt dagens klassningssystem och det nya systemet Prima-Sekunda : – En fallstudie på Mellanskog / Comparison of financial outcome when classifying pulpwood accprding to the currently used classification system and the new system Prima-SekundaOlsson, Jennie January 2019 (has links)
In August 2019, Prima-Sekunda is about to be introduced, a new classification system for the classification of pulpwood during surveying to industry. This new classification system should be more time and cost effective and at the same time offer the industries commodity volume with better quality. The purpose of this study was to compare if there was any difference in the economic outcome with the new Prima-Sekunda compared to today's classification system when measuring pulpwood. Based on the 95 piles measured, it appeared that today's classification system gives somewhat better paid than Prima-Sekunda due to the prices for Prima-Sekunda which are initially set slightly lower than today's pulpwood price. The introduction of Prima-Sekunda should be price neutral, which means that the prices for Prima-Sekunda as shown in the current study must be reasonably equal to the current pulpwood price for this goal to be materialized.
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[en] TENSEGRITY STRUCTURES AND ECO-DESIGN: AS SOLUTION FOR THE REDUCTION OF ROW MATERIAL AND ENERGY IN PRODUCT DESIGN / [pt] ESTRUTURAS TENSEGRITIES E ECO-DESIGN: ALTERNATIVA PARA REDUÇÃO DE MATÉRIA - PRIMA E ENERGIA NO DESIGN DE PRODUTOSPEDRO ZOHRER RODRIGUES DA COSTA 21 February 2006 (has links)
[pt] Este trabalho tem como objeto de estudo a técnica do
Tensegrity
como solução alternativa para a redução de matéria - prima
e energia no
design de produtos Eco-sustentáveis. O seu objetivo é
apresentar uma
série de conceitos e teorias que possibilitem o maior
entendimento sobre
o assunto e, como conseqüência, permita o surgimento de
novas
possibilidades de produtos compatíveis com a
racionalização de recursos
e energia (o Eco-design). Para chegar ao objetivo,
procedeu-se de
estudos e análises bibliográficas referentes ao que seja
Tensegrity e Ecodesign.
A esses estudos foi somada a experimentação prática como
forma de desenvolver e absorver as técnicas construtivas e
as
possibilidades projetuais do Tensegrity em relação ao Eco-
design. Tais
informações direcionam-se ao contexto educacional dos
futuros
designers, assim como de arquitetos e engenheiros. / [en] This work is intended to study tensegrity`s technique as a
solution to
ambiental buildings (constructions) and its relation with
Eco-design. The
goal is to present a series of concepts and theories that
make possible the
most agreement on the subject and, as a consequence,
allows the
emergence of new possibilities of compatible products with
the
rationalization of resources and energy (Eco-design). In
order to reach
these objectives, studies and analysis of the current
bibliography were
made, mainly under the key words tensegrity and eco-
design. Practical
experiments were added in order to develop and absorb
construction
techniques and project capabilities of tensegrity related
to eco-design.
This information could be useful for educational purposes
of future
designers, as well as architects and engineers.
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Sex pianisters uppfattning om a prima vista spel / Six pianists´s understanding of sight-readingLarsson, Carina January 2008 (has links)
<p>The main purpose of this study is to identify and compare classical pianists´ understanding of sight-reading. Six pianists were interviewed, four professionals and two students. All of them concidered good sight-reading ability to be an advantage, especially when rehearsing, but most important is to be a good musician performing music thoroughly gone through.</p>
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Talent Management in a Multicultural Environment : A new game for global companies through the football's exampleQuignon, Fabien, Vettori, Francesco January 2012 (has links)
Connecting, living and working with people coming from different horizons across the globe has never been as intese as nowadays. This bordless world increases the amount of competitors that companies have to deal with in their business environment. The importance of establishing strategies and policies, that enable to blend diversity of cultures and brains, has been noticed by many. Moreover, the increasing necessity of creating a system which is able to struggle against the shortage of talents was and is still rendering even more complicated the task and the duties of leaders and managers of today. We see in the beauty of football not only a passion for the game but also and rather an effective way to face and to cope with the aformentioned two issues. The purpose of this thesis is to spell out and to stress some aspects that emerge from football and that could be suggested as new practices to compete in the 21st century for global companies.
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Sex pianisters uppfattning om a prima vista spel / Six pianists´s understanding of sight-readingLarsson, Carina January 2008 (has links)
The main purpose of this study is to identify and compare classical pianists´ understanding of sight-reading. Six pianists were interviewed, four professionals and two students. All of them concidered good sight-reading ability to be an advantage, especially when rehearsing, but most important is to be a good musician performing music thoroughly gone through.
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Konsten att spela a prima vista : En observationsstudie / The art of sight-reading : An observation studyAschbacher, Katarina January 2014 (has links)
Syftet med denna studie är att utifrån ett sociokulturellt perspektiv, få en överblick, samt större förståelse för min egen lärandeprocess i a prima vista-spel. I bakgrundskapitlet beskrivs några metoder och strategier för att utveckla a vista-spel, samt tankesätt kring a vista-spel i dagens musiksamhälle. För att observera min övning i a vista-spel, användes videoinspelningar, loggbok samt självobservation. I övningen användes pedagogiska a vista-träningsböcker samt visböcker, med blandad repertoar. Resultatet visade att användning av redskap såsom; metronom, träningsböcker, kropp, samt noter ledde övningen framåt. God kroppshållning och teknik visade sig också vara avgörande för ett mer säkert a vista-spel. I diskussionsdelen jämförs temaresultat, metronom, material, kroppshållning, omtagningar samt noter med tidigare forskning och litteratur. / The purpose of this study is to observe and understand my learning process in sight-reading from a socio-cultural perspective. The second chapter is about the methods and strategies which can improve sight-reading and about the thoughts of sight-reading by musicians of today. Video recordings and a logbook were used to observe my practice in sight-reading. In this practice pedagogic sight-reading materials and songbooks with a wide repertoire also were used. The result showed that the use of tools like; metronome, work of material, the body, and notes of music improved my practice. For a good result a good posture and technique also proved to be important. In the last chapter my theme results, metronome, material, posture, retakes and notes of music were compared with previous research and literature.
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Thin film structures of diamond-like carbon prepared by pulsed plasma techniquesCorbella Roca, Carles 30 January 2006 (has links)
Esta tesis presenta un estudio de la síntesis y la caracterización de carbono amorfo tipo diamante (DLC) preparado en capa delgada. Este material destaca por exhibir una alta dureza, baja fricción y buena resistencia al desgaste. Gracias a sus excelentes propiedades mecánicas y tribológicas, el DLC presenta numerosas aplicaciones como recubrimiento protector y lubricante sólido. Como ejemplos, podemos citar el recubrimiento de herramientas de corte, discos duros de ordenador y prótesis ortopédicas. Las técnicas más frecuentes para el depósito de DLC son el depósito químico en fase vapor activado por plasma (PECVD), el arco catódico, y la pulverización catódica con magnetrón.Una desventaja importante presentada por las capas de DLC es su elevado esfuerzo compresivo residual, factor que limita el grosor de las capas a unas pocas decenas de nanómetros. La superación de este grosor provoca inestabilidades en el material que conducen a problemas de adhesión e incluso a la delaminación de la capa. En la literatura se proponen varias soluciones para reducir las tensiones internas del DLC y así rebajar este esfuerzo mecánico, como por ejemplo el depósito de capas metálicas de anclaje y de estructuras repetitivas en multicapa de periodo nanométrico. El objetivo de esta tesis ha consistido en preparar diferentes estructuras de DLC y modificar sus propiedades mediante la variación de los parámetros tecnológicos de depósito. El análisis de los resultados de caracterización de las muestras nos ha proporcionado su estructura, morfología, propiedades químicas, ópticas, eléctricas y de superficie.Una parte de este trabajo trata sobre el crecimiento de DLC por la técnica de PECVD mediante una fuente pulsada-DC de alta potencia que alimenta un plasma de metano. Esta tecnología ofrece varias ventajas, como la reducción del esfuerzo intrínseco del DLC y el incremento de la velocidad de depósito, todo ello logrado utilizando una instalación más económica que las tradicionales de radiofrecuencia. Se ha hecho un estudio in-situ de los parámetros del plasma pulsado (temperatura electrónica, densidades iónica y electrónica, y potencial de plasma) medinte una sonda de Langmuir en modo de resolución temporal. De esta manera, se ha apreciado la dependencia de las propiedades de las capas con respecto a las variables fundamentales del proceso de depósito.Por otro lado, también se ha considerado la incorporación de átomos metálicos (Mo, Nb, Ti, W) en la red de carbono mediante la técnica de depósito de pulverización reactiva con magnetrón en atmósfera de argón y metano. Las capas de DLC con contenido metálico, que presentan una nanoestructura y una cristalinidad determinadas por el metal añadido y su abundancia, sufren un menor esfuerzo merced a una estructura más relajada sin que por ello se resienta en gran medida la dureza. Las propiedades tribológicas también se ven favorecidas al mostrar valores muy bajos (~0.03) de coeficiente de fricción. / THESIS SUMMARY:This thesis reports the study of the synthesis and characterisation of thin films of diamond-like carbon (DLC). This material exhibits high hardness, low friction and low wear rate. Due to its excellent mehanical and tribological properties, the DLC shows several applications as protective coating and solid lubricant. We can mention for instance coatings addressed to cutting tools, hard-disk drives and orthopedic implants. DLC films are commonly deposited by plasma-enhanced chemical vapor deposition (PECVD), cathodic arc, and magnetron sputtering.An important drawback of DLC films is their high residual compressive stress, which limits film thickness to a few tens of nanometers. Strong instabilities of the material are promoted by the overcoming of this thickness, leading to adhesion problems and even to film delamination. Some of the solutions proposed in the literature consist on the deposition of metallic buffer layers and multilayer structures of nanometric period. The aim of this thesis consisted on the preparation of different structures of DLC and the tailoring of their properties by varying the technological parameters of deposition. The analysis of the characterisation results of the samples provided us their structure, morphology, and chemical, optical and electrical properties.A part of this work deals with the growth of DLC by means of PECVD technique using a pulsed-DC power supplier that drives a methane plasma. This technology provides several advantages, as for example the reduction of the intrinsic stress of DLC and the increase of the deposition rate, being this achieved by making use of an installation more cost-effective than the employed for radiofrequency. The parameters of the pulsed plasma (electron temperature, ion and electron densities, and plasma potential) have been studied by means of a Langmuir probe in time-resolution mode. Thus, the film properties have been related to fundamental variables of the deposition process.On the other hand, we have also considered the incorporation of metal atoms (Mo, Nb, Ti, W) within the carbon network by means of reactive magnetron sputtering in an argon and methane mixture. The metal-containing DLC films, which present a nanostructure and crystallinity determined by the added metal and its abundance, suffer a lower stress thanks to a more relaxed structure without reducing significatively the hardness. The low values of the friction coefficient (~0.03) are indicative of the improvement of the tribological properties.
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Household heterogeneity and Incomplete Financial Markets: Asset Return Implications in a Real Business Cycle SetupCarceles Poveda, Eva 23 October 2001 (has links)
Uno de los problemas principales de la literature moderna de ciclos es la imposibilidad de replicar el comportamiento de los rendimientos de activos financieros. Varios autores han incorporado mercados financieros en el modelo basico de ciclos, demonstrando que, para cualquier calibracion, este tipo de modelos predice una prima de riesgo de practicamente cero. Una de las razones del fracaso de estos modelos es que utilizan un agente representativo. En este caso los mercados financieros son completos. En esta tesis relajamos este supuesto al incorporar riesgo idiosincratico, que genera heterogeneidad entre la poblacion. Uno de los objectivos principales es ver si estas extensiones pueden ayudar a mejorar las predicciones del modelo basico con respecto a los rendimientos de activos financieros. Debemos mencionar que, desde la formulacion original de los puzzles financieros de Mehra y Prescott (85), ha surgido una enorme literatura que intenta analizar las implicaciones de modelos con heterogeneidad respecto a los rendimientos de los activos financieros. Entre otros Aiyagari and Gertler (91), Heaton and Lucas (96), Lucas (94), Marcet and Singleton (99), y Telmer (93) han estudiado este problema bajo el supuesto de que el consumo es exogeno. Si embargo, en nuestro analisis incorporamos production y por tanto ofrecemos un modelo mucho mas apropiado para estudiar los rendimientos financieros. En particular, el consumo se deriva de la maximizacion de la utilidad y por tanto no es exogeno. Ademas, el valor de las acciones se determina a traves de la optimizacion de la empresa. La presencia de un sector de produccion implica que tenemos que tratar un tema al que no se le ha dado demasiada importancia hasta ahora en la literatura. Con mercados financieros incompletos y heterogeneidad de los accionistas, el problema de maximizacion del valor de la empresa no esta bien definido. Esto significa que tenemos que incorporar objectivos que no son estandares. Una de las contribuciones importantes de este trabajo es demostrar como se puede solucionar este problema. / One of the main problems with the modern real business cycle (RBC) literature is its inability to replicate the empirical behavior of the main asset returns in the data. Several authors have incorporated financial markets into the basic model showing that, regardless of the parameterization or the incorporation of other frictions, like capital adjustment costs, these models are unable to replicate the key financial statistics in the data, predicting an equity premium which is essentially zero, and asset return volatilities that are also far from reality. One of the main reasons for the lack of success of the previous models may be the fact that they are using a representative agent environment. In this case, financial markets are effectively complete, independently of the existing asset structure. In the present thesis, this assumption is relaxed by incorporating both, idiosyncratic labor income risk and imperfect risk sharing, leading to ex-post household heterogeneity and to an incomplete financial market structure. One of the main objectives is therefore to see, if these extensions can help to improve the asset pricing implications of the standard model. We have to mention that, since the original statement of the asset pricing puzzles by Mehra and Prescott (85), there has been a large strand of literature trying to analyze the asset pricing implications of a context with household heterogeneity and incomplete financial markets. Among others, Aiyagari and Gertler (91), Heaton and Lucas (96), Lucas (94), Marcet and Singleton (99), and Telmer (93) have studied such a framework under the assumption of exogenously determined asset returns and consumption processes. Note, however, that our analysis goes one step further in the sense that it incorporates a production technology, offering a better foundation of asset prices than the standard exchange economy. In particular, consumption is derived from explicit utility maximization instead of being specified exogenously. In addition, the value of price of equity is determined endogenously via the optimization problem of the firm, which also breaks the identity between dividends and consumption processes in exchange economies. We indeed believe, that a detailed and rigorous analysis of asset pricing requires a general equilibrium model of this type. Note also that the presence of a non-trivial production sector involves addressing an important issue, which has not been given very much attention in the previous asset pricing literature. Under incomplete financial markets and household (shareholder) heterogeneity, the usual profit maximization of the firm is no longer well defined. Thus, unless one assumes that the firm is myopic, in the sense that it solves a static optimization problem by maximizing period by period profits, one has to incorporate non-standard firm objectives into the model. A second important objective or contribution of the present thesis is therefore to illustrate how to get around the problem of the firm by incorporating a firm objective which is adequate for the case in which financial markets are incomplete.
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