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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.
231

Pre-fermentation maceration of pinot noir wine

Goldsworthy, S. A. January 1993 (has links)
Two pre-fermentation treatments were investigated in Pinot noir (Vitis vinifera L.) wines. The effects of cold maceration and carbonic maceration on the wines' composition, colour parameters and sensory properties were examined. Cold maceration is a winemaking technique used to increase non-alcoholic extraction in Pinot noir winemaking prior to fermentation. It involves holding crushed grapes with approximately 100-150 mg l⁻¹ SO₂ at low temperatures and is thought to increase the colour, aroma and flavour of the resulting wines. Carbonic maceration uses whole bunches that have undergone anaerobic metabolism to produce characteristically fruity and spicy wines. Pre-fermentation cold maceration produces wines that are higher in titratable acidity and monomeric anthocyanin content, but lower in colour density, hue and polymeric pigments. Reducing the maceration temperature below 10°C has little effect. Carbonic maceration produces wines that are lower in titratable acidity, monomeric anthocyanin content, and colour density but are higher in colour hue and amount of polymeric pigments. Quantitative descriptive analysis was used to define the effects of these pre-fermentation maceration treatments on the sensory characteristics of the resulting wine. Trained panel members found that there were no discernable sensory differences in the compositional parameters despite measurable chemical differences. Investigation into the aroma and flavour characteristics of the wines found that carbonic maceration produces wines that were lower in berry aroma and higher in acetate or ester-type aromas than the control wines. These wines were considered to have specific raspberry, floral, sugar, cherry and chemical aromas. This chemical note was also observed in the flavour of the carbonic maceration wines. The temperature of the cold maceration process has no major effect on the aroma and flavour of the resulting wines. However, the 10°C maceration was higher in woody/tobacco aroma than the 4°C maceration, and the 10°C treatment was also higher in bitter flavour than all the other treatments. Cold maceration wines were found to have specific mixed berry, dried fruit and sweet-oxidised aroma characters, together with a blackberry flavour note.
232

Physico-Chemical Characterization of Drugs: Acidity and Solubility

Shoghi Kalkhoran, Elham 15 January 2013 (has links)
The aim of the present work was to contribute to establish robust and high throughput methodology of interest in the "Drug Discovery" step commonly done in pharmaceutical laboratories. This purpose involves the exploration of the possibilities of the potentiometric Sirius methodology to determine both acidity constants and solubilities of drugs and other bioactive compounds and also to do a study about how to improve bioavailability of a model drug, Amphotericine 8, by increasing its dissolution rate. In the first part of this project, the acidic dissociation enthalpies and constants of anilinium, protonated tris (hydroxymethyl)- aminomethane (HTris+), benzoic and acetic acids, have been determined at several temperatures in pure water and in methanol/water mixtures by potentiometry method. The pK(a) values determined by this technique are in accordance with those values determined by ITC method in our laboratory and also with those other values from literature. Also dissociation enthalpies can be obtained from potentiometric pK(a) values by means of the Van't Hoff approach and these obtained values are in agreement with those ones determined directly by calorimetry in our laboratory. In the second part, we focused on studying about solubility. The Chasing Equilibrium method offers an alternative to the classical procedures to measure the solubility of compounds with acid-base properties. The method is fast and yields accurate results. In this work, the solubility of several compounds including acids and bases was determined through the Chasing Equilibrium approach. A study of experimental conditions in terms of sample weight was performed to measure solubilities. The study shows that only a limited range of weights, depending on the nature and solubility of the compounds, is adequate to obtain reliable results. In the third part of this work, the solubility vs. pH profiles of five ionizable drugs of different nature (a monoprotic acid, a monoprotic base, a diprotic base and two amphoteric compounds showing a zwitterionic species each one) have been determined through two different methodologies: the classical Shake-Flask (S-F) and the potentiometric Cheqsol methods using in both instances the appropriate Henderson-Hasselbalch (H-H) or derived relationships. The results obtained independently from both approaches are consistent. A critical revision about the influence of the electrolyte used as buffering agent in the S-F method on the obtained solubility values is also performed. Thus, some deviations of the experimental points with respect the H-H profiles can be attributed to specific interactions between the buffering electrolyte and the drug due to the hydrotrophic character of citric and lactic acids. In other cases, the observed deviations are independent of the buffers used since they are caused by the formation of new species such as drug aggregates (cefadroxil) or the precipitation of a salt from a cationic species of the analysed compound (quetiapine). In the forth part, the objective was to compare the dissolution behavior of tablets prepared from solid dispersions prepared in DMSO dissolvent with and without drug-carrier and also with and without surfactants in aqueous and acidic solutions. Amphotericine B was used as a model drug. Two types of carriers were used; mannitol, inulin. Solid dispersions with two different drug loads were prepared by freeze drying method. It was found that the drug dissolution rate in aqueous and acidic solutions was significantly increased in the presence of drug-carrier and surfactants. X-ray powder diffraction revealed that all solid dispersions were fully amorphous. / El objetivo del presente trabajo ha sido contribuir a establecer metodología robusta y de high throughput de interés en la etapa conocida como "Drug Discovery" que tiene lugar en los laboratorios farmacéuticos al inicio del proceso de desarrollo de nuevos fármacos. Este objetivo ha implicado la exploración de las posibilidades de la metodología potenciométrica establecida y comercializada por Sirius Analytical Ltd. para la determinación de las constantes de acidez y de la solubilidad de compuestos bioactivos y también un estudio sobre la mejora de la biodisponibilidad de un fármaco muy insoluble tomado como modelo mediante el aumento de su velocidad de disolución. En la primera parte de esta Tesis se han determinado potenciométricamente las constantes de disociación ácida y la variación de entalpía asociada de dos bases y dos ácidos tomados como modelo en agua pura y en mezclas de metanol/agua (0-60% w/w) a varias temperaturas (25-55°C). Esto ha implicado la puesta a punto de la estandarización del sistema potenciométrico en las condiciones de trabajo. Los valores de pK(a) determinados son concordantes con los que ofrece la literatura. Se han calculado también las entalpias de disociación en los distintos solventes binarios estudiados mediante la ecuación de Van't Hoff a partir de los valores experimentales de pK(a). La consistencia de los resultados obtenidos con los de la literatura, obtenidos directamente por calorimetría, confirma la robustez de la metodología. En la segunda parte de este trabajo, el estudio se centró sobre la determinación potenciométrica de la solubilidad de ácidos y bases mediante el método conocido como Chasing Equilibrium, como alternativa a los procedimientos clásicos de equilibración. El método es rápido y produce resultados precisos. Se ha realizado un estudio sobre las condiciones experimentales óptimas en términos de peso de la muestra para medir eficazmente la solubilidad. El estudio muestra que, en función de la naturaleza y solubilidad de los compuestos, existe un intervalo limitado de peso de muestra adecuado para obtener resultados fiables. En la tercera parte de la presente memoria, se estudian los perfiles de solubilidad en función del pH de cinco fármacos ionizables de naturaleza diferente, un ácido y una base monopróticos, una base diprótica y dos compuestos anfóteros que muestran una especie zwitteriónica cada uno. Se han determinado los perfiles de solubilidad mediante el método clásico de equilibración (Shake-Flak, S-F) y el potenciómétrico y, en ambos casos, se han utilizado las relaciones apropiadas de Henderson-Hasselbalch (H-H) o derivadas. Los resultados obtenidos de forma independiente por ambos métodos son consistentes. Se ha hecho un estudio crítico acerca de la influencia del electrolito utilizado como agente tampón en el método S-F en los valores de solubilidad obtenidos y se han observado algunas desviaciones de los puntos experimentales con respecto a los perfiles esperados que pueden ser debidas a interacciones específicas entre el electrolito tampón y el fármaco. En otros casos, las desviaciones observadas son independientes de los tampones utilizados y se pueden atribuir a la formación de nuevas especies tales como agregados iónicos del fármaco en estudio o la precipitación de una sal a partir de una especie catiónica del compuesto analizado. En la cuarta parte de esta memoria el objetivo ha sido estudiar la velocidad de disolución de comprimidos preparados a partir de dispersiones sólidas de un fármaco modelo con y sin portador del fármaco y también en presencia y en ausencia de tensioactivo en soluciones acuosas neutras y ácidas. Como fármaco modelo se estudió la Anfotericina B y se utilizaron como portadores manitol e inulina y como tensioactivos se ensayaron el deoxicolato de sodio (SDC) y el laurilsulfato de sodio (SLS). La difracción de rayos X reveló que el fármaco en estudio se hallaba en estado amorfo en todas las dispersiones sólidas estudiadas. Se puede concluir que la velocidad de disolución del fármaco se incrementa significativamente en presencia de portador y tensioactivo.
233

Lizocimo įtaka pieno technologinėms savybėms / The Influence of Lysozyme on the Milk Technological Properties

Šapošnikova, Jelena 06 June 2006 (has links)
Work size - 60 pages, including 35 pictures, 1 table. List of literature - 44 sources. The beginning of the work -2004 09 01, the end of the work - 2006 05 15. Purpose of work: To explore, what influence the additive lysozyme on technological properties of milk which are important in manufacture of fermental cheeses and sour - milk products has. In work presents the analysis of lysozyme influence on the technological properties of. The results show that lysozyme prevent to develop of undesirable microorganisms and positively influences on the quality of fermented milks. It was established that the additive of lysozyme prolongs the duration of the bactericidal phase. The investigation of the rennet formation time has shown that the clothing of the milk in samples with lysozyme formed 12 - 15  faster as in compared with the control sample without lysozyme. Besides, it is established, that the additive of lysozyme intensifies the process removal of the whey. The research investigation show that in samples with lysozyme, whey distinguish in smaller optical density as compared with control samples. The development of lactic bacteria during fermentation process was examined too. It was found that lysozyme influence on this process is very insignificant. It was established that the additive of lysozyme insignificant reduces viscosity and acidity of fermented milk gels.
234

Investigation Of 8-year-long Composition Record In The Eastern Mediterranean Precipitation

Isikdemir, Ozlem 01 January 2006 (has links) (PDF)
Measurement of chemical composition of precipitation is important both to understand acidification of terrestrial and aquatic ecosystems and neutralization process in the atmosphere. Such data are scarce in the Mediterranean region. In this study, chemical composition of daily, wet-only, 387 number of rain water samples collected between 1991 and 1999 were investigated to determine levels, temporal variation and long-term trends in concentrations of major ions and trace elements between 1991 and 1999. Samples had already been collected and some of the analysis had been completed. The anions SO42-, NO3- and Cl- were analyzed by HPLC coupled with UV-VIS detector, NH4+ was analyzed by colorimetry and H+ ion was analyzed by pH meter. The major ions and trace metals were analyzed by using Atomic Absorption Spectrometry (AAS) and Graphite Furnace Atomic Absorption Spectrometry (GFAAS). In this study complete data set were generated by analyzing samples that had not been previously analyzed for major ions and trace elements with Inductively Coupled Plasma with Optical Emission Spectrometry (ICP-OES). Statistical tools were used to determine the distribution of the pollutants. The rain water data tends to be log-normally distributed since data show large variations due to meteorological conditions, physical and chemical transformations and air mass transport patterns. The median pH of the rain water was found to be 5.29, which indicates that the rain water is not strongly acidic. This case is not a result of lacking of acidic compounds but rather indicates extended neutralization process in rain water. Eastern Mediterranean atmosphere is under the influence of three general source types: (1) anthropogenic sources, which are located to the north and northwest of the basin brings low pH values to the region (SO42-, NO3- ions) / (2) a strong crustal source, which is dried and suspended local soil and air masses transported from North Africa transport which have high pH values (Ca2+, Al, Fe ions) and (3) a marine source, which is the Mediterranean Sea itself (Na+, Cl- ions). In the region, the main acid forming compounds are H2SO4 and HNO3 whereas / CaCO3 and NH3 are responsible for the neutralization process. To describe the level of pollutant concentrations and the factors that affect their variations in rain water / ion compositions, neutralization of acidity, short and long-term variability of ions and elements, their time trend analysis and wet deposition fluxes were investigated briefly. Positive matrix factorization (PMF) was used to determine components of ionic mass in the precipitation. In Antalya Station the rain water has five factors: free acidity factor, crustal factor, marine factor, NO3- factor and SO42- factor. Potential Source Contribution Function (PSCF) and trajectory statistics were used to determine source regions generating these components. NO3- has potential source regions of Western Mediterranean countries and North Africa, whereas SO42- has additional southeasterly trajectory components of Israel and south east of Turkey.
235

Synthesis and characterization of catalysts for the total oxidation of chlorinated volatile organic compounds

El Assal, Z. (Zouhair) 30 November 2018 (has links)
Abstract The harmful emissions of chlorinated volatile organic compounds (CVOCs) originate only from man-made sources. CVOCs are used in a variety of applications from pharmaceuticals production to decaffeination of coffee. Currently, CVOC emissions are limited by strict legislation. For these reasons, efficient CVOC abatement technologies are required. Catalytic oxidation is very promising option for this purpose, since catalysts can be tailored to each case to maximize the efficiency and minimize the formation of unwanted products, such as dioxins or Cl2. The goal of this thesis was to study the role of the physico-chemical properties of catalysts in dichloromethane (DCM) oxidation. To reach the aim, several catalytic materials were prepared and characterized, and their performance was tested in total oxidation of DCM. The catalytic materials used were powders of four single metal oxides (γ-Al2O3, TiO2, CeO2, MgO), three mixed oxides (Al2O3-xSiO2) washcoated on a cordierite monolith and four active phases (Pt, Cu, V, Mn). At first, support properties were studied. It was found that the DCM conversion and HCl production are dependent on support acidity when the studied single oxides are considered. The best DCM conversions and HCl yields were observed with the support having the highest total acidity (γ-Al2O3). Further, the quality of the by-products formed was dependent on the type of the acid sites present on the support surface. Secondly, the impregnation of the active compound was observed to improve the selectivity of the material. From the tested active phases, Pt presented the best performance, but also V2O5 and CuO showed almost equal performances. Especially CuO supported on γ-Al2O3, that had less formation of by-products and is less toxic than V-containing oxides, seems to be a promising alternative to Pt. Concerning stability, no deactivation was observed after 55h of testing of Pt/Al2O3. Furthermore, in the used reaction conditions, the formation of CuCl2 is not thermodynamically favoured. Finally, the good characteristics of the powder form catalysts were successfully transferred to the monolith. The performance of the Pt/90Al2O3-10SiO2 catalyst in DCM oxidation was improved when the channel density was increased due to an increase in geometric surface area and mechanical integrity factor, and a decrease in open fraction area and thermal integrity factor. / Tiivistelmä Haitallisten kloorattujen orgaanisten yhdisteiden (CVOC) päästöt ovat ihmisten aiheuttamia. CVOC-yhdisteitä käytetään mm. liuottimina lääkeaineiden valmistuksessa ja kofeiinin poistossa. Nykyisin CVOC-päästöjä rajoitetaan tiukalla lainsäädännöllä. Näistä syistä tehokas CVOC-yhdisteiden käsittelymenetelmä on tarpeen. Katalyyttinen hapetus on hyvä vaihtoehto tähän tarkoitukseen, koska katalyytit voidaan räätälöidä niin, että puhdistuksen tehokkuus saadaan maksimoitua samalla kun ei-haluttujen tuotteiden, kuten dioksiinit ja kloorikaasu, muodostuminen voidaan minimoida. Tämän väitöskirjatyön tavoitteena oli selvittää katalyyttien fysikaalis-kemiallisten ominaisuuksien yhteyksiä dikloorimetaanin (DCM) hapetukseen. Tavoitteen saavuttamiseksi valmistettiin useita katalyyttejä, jotka karakterisoitiin ja testattiin DCM:n kokonaishapetuksessa. Työssä tutkittiin neljää jauhemaista metallioksidia (γ-Al2O3, TiO2, CeO2 ja MgO), kolmea metallioksidiseosta (Al2O3-xSiO2), jotka pinnoitettiin kordieriittimonoliitille, sekä neljää aktiivista ainetta: Pt, Cu, V and Mn. Aluksi työssä keskityttiin tukiaineiden ominaisuuksiin. Työn tulokset osoittivat, että DCM:n konversio ja HCl:n tuotanto ovat riippuvaisia tukiaineen happamuudesta. Paras tulos saavutettiin alumiinioksidilla, jolla oli korkein kokonaishappamuus. Lisäksi havaittiin, että sivutuotteiden laatu riippuu tukiaineen pinnalla olevien happopaikkojen tyypistä. Aktiivisen aineen impregnointi tukiaineeseen paransi materiaalin selektiivisyyttä. Tutkituista aineista Pt osoittautui parhaimmaksi, mutta myös V2O5 ja CuO olivat lähes yhtä hyviä. Erityisesti CuO-katalyytti, joka tuotti vähemmän sivutuotteita ja joka on materiaalina vähemmän haitallinen kuin V2O5, osoittautui lupaavaksi jalometallikatalyyttien korvaajaksi. Materiaalien stabiilisuuteen liittyen Pt/Al2O3-katalyytin toiminnassa ei havaittu muutoksia 55 tunnin testauksen jälkeen. Lisäksi CuCl2:n muodostuminen ei mallinnuksen mukaan ole termodynaamisesti todennäköistä tutkituissa reaktio-olosuhteissa. Jauhemaisen katalyytin hyvät ominaisuudet pystyttiin pinnoituksessa siirtämään monoliittirakenteiseen katalyyttiin. Pt/90Al2O3-10SiO2 -katalyytin aktiivisuus DCM:n hapetuksessa tehostui, kun monoliitin aukkoluku kasvoi aiheutuen suuremmasta geometrisestä pinta-alasta ja mekaanisesta eheystekijästä sekä pienemmästä avoimen pinnan osuudesta ja termisestä eheystekijästä.
236

Vztah výměnné acidity a iontovýměnné kapacity v kambizemích Jihočeského kraje.

NOVÁK, Jiří January 2016 (has links)
Literature search was processed , which were generally described concepts relating to soil complex, but also various soil types, with a focus on cambisol South Bohemia. Additionally the general explained concepts regarding acidification and ion-exchange complex soils. In the practical part of the work was determined by measurement of exchangeable soil acidity. Based on this measurement Soils were evaluated as slightly acidic. It was also calculated the need for healing liming locations. It was also determined the maximum sorption capacity. Soil collected on site has been categorized soils with moderate capacity ion-exchange sorption complex.
237

Modélisation des relations structure / propriétés de transport de charge dans les matériaux pour l'électronique organique / Structure/charge transport relationships in molecular and polymeric materials for organic electronics through atomistic modeling

Gali, Sai Manoj 10 October 2017 (has links)
Les avancées technologiques et l'intégration massive de dispositifs électroniques nanométriques dans les objets de notre vie quotidienne ont généré une explosion des coûts de R&D, de conception et de production, ainsi que des inquiétudes sociétales quant à l'impact environnemental des déchets électroniques. En raison de procédés de production moins coûteux et à faible impact environnemental, de leur souplesse d’utilisation et de la possibilité de moduler leurs propriétés à l’infini, les molécules et polymères organiques constituent une classe de matériaux prometteuse pour la mise au point de nouveaux dispositifs électroniques. L’électronique organique couvre ainsi un vaste domaine d’applications, parmi lesquelles se trouvent les diodes électroluminescentes, les transistors à effet de champ ou les cellules photovoltaïques. Bien que la plupart de ces dispositifs soient déjà commercialisés, les processus gouvernant leur efficacité à l’échelle atomique sont loin d’être entièrement compris et maîtrisés. C’est en particulier le cas des processus de transport de charge, qui interviennent dans tous ces dispositifs.L'objectif de cette thèse est d’apporter une compréhension fondamentale des processus de transport de charge dans les semiconducteurs organiques, à partir d'approches théoriques combinant dynamique moléculaire, calculs quantiques et simulations Monte Carlo. Ce travail est développé suivant trois axes principaux:(I) Etude des relations liant l'organisation structurale et les propriétés de transport de cristaux moléculaires, et du rôle des fluctuations énergétiques dans des matériaux polymères amorphes. Des simulations Monte Carlo Cinétique (KMC) couplés au formalisme de Marcus-Levich-Jortner pour le calcul des taux de transfert ont été effectués afin de déterminer les mobilités des électrons et des trous au sein de dix structures cristallines de dérivés phtalocyanines. Dans une deuxième étude, une approche similaire a été employée afin de décrire les propriétés de transport de charge au sein d'un copolymère amorphe de fluorène-triphénylamine, ainsi que l'impact des fluctuations énergétiques sur ces dernières. La méthodologie développée permet d'obtenir, pour un faible coût calculatoire, une estimation semi-quantitative des mobilités des porteurs de charge dans ce type de système.(II) Etude de l'impact de contraintes mécaniques sur les propriétés de transport de matériaux organiques cristallins. La réponse électronique et les propriétés de transport de matériaux organiques soumis à une contrainte mécanique ont été étudiés à l'aide de simulations de dynamique moléculaire et de calculs DFT. Le rubrène cristallin et ses polymorphes, ainsi que les dérivés du BTBT, ont été considérés pour cette étude, qui révèle un couplage électromécanique inhabituel entre les différents axes cristallographiques. Les résultats démontrent en particulier que l'anisotropie structurale des monocristaux organiques conduit à une anisotropie du couplage électromécanique.(III) Etude du rôle du polyélectrolyte dans la conductivité des complexes conducteurs. Le polystyrène substitué par du bis(sulfonyl)imide est utilisé comme un contre-ion et un dopant dans les complexes conducteurs PEDOT-polyélectrolytes. En complément des analyses expérimentales, des simulations de dynamique moléculaire couplées à des calculs DFT ont été effectuées dans ces systèmes afin d'analyser l'impact de la conformation et de l'état de protonation du polyélectrolyte sur la conductivité du complexe formé avec le PEDOT.Les études décrites ci-dessus, réalisées sur différents types de matériaux en couplant différents types d'approches théoriques, ont permis d'apporter une compréhension fondamentale des propriétés de transport dans les semiconducteurs organiques. Elles mettent en particulier en évidence l'impact de l'organisation structurale, des interactions intermoléculaires et de l'application de contraintes mécaniques sur la mobilité des porteurs de charges dans ces matériaux. / With the advancement of technology, miniaturized electronic devices are progressively integrated into our everyday lives, generating concerns about cost, efficiency and environmental impact of electronic waste. Organic electronics offers a tangible solution paving the way for low-cost, flexible, transparent and environment friendly devices. However, improving the functionalities of organic (opto) electronic devices such as light emitting diodes and photovoltaics still poses technological challenges due to factors like low efficiencies, performance stability, flexibility etc. Although more and more organic materials are being developed to meet these challenges, one of the fundamental concerns still arises from the lack of established protocols that correlate the inherent properties of organic materials like the chemical structure, molecular conformation, supra-molecular arrangement to their resulting charge-transport characteristics.In this context, this thesis addresses the prediction of charge transport properties of organic semiconductors through theoretical and computational studies at the atomistic scale, developed along three main axes :(I) Structure-charge transport relationships of crystalline organic materials and the role of energetic fluctuations in amorphous polymeric organic semiconductors. Kinetic Monte-Carlo (KMC) studies employing the Marcus-Levich-Jortner rate formalism are performed on ten crystalline Group IV phthalocyanine derivatives and trends linking the crystalline arrangement to the anisotropic mobility of electrons and holes are obtained. Subsequently, KMC simulations based on the simpler Marcus formalism are performed on an amorphous semiconducting fluorene-triphenylamine (TFB) copolymer, to highlight the impact of energetic fluctuations on charge transport characteristics. A methodology is proposed to include these fluctuations towards providing a semi-quantitative estimate of charge-carrier mobilities at reduced computational cost.(II) Impact of a mechanical strain on the electronic and charge transport properties of crystalline organic materials. Crystalline rubrene and its polymorphs, as well as BTBT derivatives (well studied high mobility organic materials) are subjected to mechanical strain and their electronic response is analyzed. Employing tools like Molecular Dynamic (MD) simulations and plane wave DFT (PW-DFT) calculations, unusual electro-mechanical coupling between different crystallographic axes is demonstrated, highlighting the role of inherent anisotropy that is present in the organic single crystals which translates in an anisotropy of their electro-mechanical coupling.(III) Protonation-dependent conformation of polyelectrolyte and its role in governing the conductivity of polymeric conducting complexes. Polymeric bis(sulfonyl)imide substituted polystyrenes are currently employed as counter-ions and dopants for conducting poly(3,4-ethylenedioxythiophene) (PEDOT), resulting in PEDOT-polyelectrolyte conducting complexes. Employing MD simulations and DFT calculations, inherent characteristics of the polyelectrolyte like its acid-base behavior, protonation state and conformation, are analyzed in conjunction with available experimental data and the role of these characteristics in modulating the conductivity of resulting PEDOT-polyelectrolyte conducting complexes is highlighted.The above studies, performed on different organic electronic systems, emphasize the importance of inherent characteristics of organic materials in governing the charge transport behavior in these materials. By considering the inherent characteristics of organic electronic materials and systematically incorporating them into simulation models, accuracy of simulation predictions can be greatly improved, thereby serving not only as a tool to design new, stable and high performance organic materials but also for optimizing device performances.
238

Estudo comparativo entre manejos de secagem e armazenamento de arroz na incidência de fungos toxigênicos e micotoxinas / A comparative study among rice drying and storage methodsin the incidence of toxigenic fungi and micotoxins

Bianchini, Andréia January 2003 (has links)
No Brasil o arroz tem um consumo alto e regular, o que exige sistemas de armazenamento que ofereçam produto de qualidade durante todo o ano. Sabe-se que a presença de fungos durante a estocagem de cereais reduz a qualidade desses produtos, além de uma possível produção de micotoxinas. Assim, torna-se clara a importância da elucidação do papel de algumas das variáveis que têm influência sobre a contaminação fúngica e por micotoxinas na estocagem, permitindo que essas possam ser posteriormente controladas. Nesse contexto está o objetivo desse estudo que compara três manejos de secagem e armazenamento de arroz, buscando o mais eficiente na redução da contaminação fúngica e por micotoxinas e elucida o comportamento das variáveis de influência no processo. Para isso foram utilizados três silos pilotos, onde o Silo 1 possuía aquecimento do ar de entrada pela queima de GLP, o Silo 2 um sistema de acionamento vinculado às condições do ar ambiente e o Silo 3 era operado manualmente. Durante o experimento foram feitas medidas diárias de temperatura, umidade e umidade relativa (UR) da massa de grãos no silo. As análises de micotoxinas, acidez e enumeração fúngica foram realizadas quinzenalmente nos primeiros 75 dias (secagem) e mensalmente após esse período até que se completasse 255 dias. Foram ainda isolados e identificados fungos dos gêneros Aspergillus e Penicillium para verificar o seu potencial toxigênico. As análises estatísticas dos resultados demonstraram que durante a operação de secagem integrada ao armazenamento os melhores resultados para a enumeração fúngica foram obtidos para os Silos 1 e 3, independentemente da altura. Já para a operação de exclusivo armazenamento, o Silo 3 apresentou o melhor resultado para a Altura 1 e o Silo 1 para a Altura 2. Quanto à presença de micotoxinas foi detectada zearalenona em níveis de até 5.850μg/Kg e 1.840μ.g/Kg nos Silos 1 e 2, respectivamente. As espécies fúngicas de maior freqüência foram Penicíllum crustosum, P. canescens e P. implicatum. Dentre as espécies testadas foram identificados dois isolados de Aspergillus flavus produtores de aflatoxina B1 e B2. As variáveis que influenciaram a contaminação fúngica foram umidade, tempo, temperatura e UR, em ordem decrescente de influência. A avaliação da acidez lipídica nos silos demonstrou que cada sistema foi influenciado por um grupo particular de variáveis. As variáveis que influenciaram a freqüência das espécies fúngicas isoladas foram a UR e a umidade, de modo regular. / In Brazil, rice is widely and regularly consumed, what requires storage systems that maintain products with quality, including between harvest period. Besides producing mycotoxins, molds are known to decrease cereais' nutritional and comercial value during storage period. Thus, it becomes clear that knowing the role of some influent variables in this process is very important. This way, it will permit a future control of these variables, maintaining rice quality during storage. Inside this context is the aim of this work, that compares three rice drying and storage handling, elucidating influence variables behaviour in each handling technique. For this purpose, three pilot silos were used. One of the silos had a heating system which ran on petroleum liquid gas (Silo 1), the second one had an activating system linked to the room air conditions (Silo 2) and the last was manually handled (Silo 3). During ali the observation period, dayly measures of temperature, moisture and relative humidity (RH) were taken from the silo's grain mass. Micotoxin, acidity and fungi total count analysis were performed every fifteen days during the first 75 drying days and monthly afterwards, until it reached the 255th day. At the same time were isolated and identificated Aspergillus and Penicillium fungi genera to evaluate their toxigenic potenctial. Result statistics analysis showed in a drying step (0-75 days), that the most efficient silos, concerning fungi count, were Silo 1 and 3, regardless of silo height sampling. For the second process stage, Silo 3 was the one that showed the best results for the highest sampling and Silo 1 for the lowest sampling. In Silo 1 and 2 the highest mycotoxin leveis detected were 5.8504/Kg and 1.840μg/Kg, respectively. The most frequently isoleted molds were Penicillum crustosum, Penicillium canescens and Penicillium implicatum. Among the tested potentially toxigenic species, two isolated producing aflatoxins B1 and B2 were identified as Aspergillus flavus. During the experiment, the variables that influenced on the fungi contamination were moisture, time, temperature, and RH, in a decreasing order of influence. The evaluation lipidic acidity in each of the silos showed that each system influenced by a specific group of variables, among the evalueted ones. The analisys allowed verifying the interaction among the variables is relevant for the evaluation of the system as a whole. The evaluation of abiotic factors influence over isolated species frequency showed that there is a regular correlation between species and RH and moisture.
239

Atributos químicos do solo e estado nutricional de cafeeiros em diferentes densidades populacionais

Paulo, Edison Martins [UNESP] 01 April 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-01Bitstream added on 2014-06-13T19:46:28Z : No. of bitstreams: 1 paulo_em_dr_ilha.pdf: 392548 bytes, checksum: 5fc7a09763e6a48500ac59e54134ef10 (MD5) / A produção trienal de café, os atributos químicos do solo e o teor foliar dos macronutrientes em cultivares de cafeeiro (Coffea arabica L.) sob diferentes densidades de plantio foram avaliados em Adamantina, município situado na região da Alta Paulista (SP), entre maio de 1995 e fevereiro de 2000. As cultivares de café Catuaí Amarelo (IAC 47) e Obatã (IAC 1669- 20), de porte baixo, e Acaiá (IAC 474-19) e Icatu Amarelo (IAC 2944), de porte alto foram estabelecidas em covas com uma planta, distanciadas por 1,0 m entre si na linha de plantio, nas densidades populacionais de 2500, 5000, 7519 e 10000 plantas por hectare. A população de 2500 plantas por hectare com duas plantas por cova também foi estudada. Adotou-se o delineamento estatístico de blocos ao acaso com três repetições, com parcelas subdivididas, correspondendo às parcelas as populações e às subparcelas as cultivares. A adubação recomendada por área foi distribuída igualmente entre as plantas de cada tratamento. A calagem não foi feita após o plantio dos cafeeiros. A produção trienal de café por área e por planta foi maior nos cafeeiros de porte baixo, que não diferiram entre si. O aumento da população de cafeeiros causou maior produção trienal de café por área e diminuição da produção por planta. Os cafeeiros das covas com duas plantas produziram mais café. Cinco anos após o plantio os solos das cultivares de cafeeiro diferiram nos teores de matéria orgânica, de cálcio e de potássio, respectivamente nas camadas 0-20 e 20-40 cm, 0-20 cm e 20-40 cm, e foram semelhantes nos demais atributos químicos do solo. Nas camadas 0-20 cm e 20-40 cm dos solos da Icatu Amarelo e Catuaí Amarelo a matéria orgânica aumentou com a população dessas cultivares e foi maior nos solos com dois cafeeiros por cova. O aumento da densidade populacional resultou na camada 20-40 cm do solo maiores teores... / The triennial production of coffee, the soil chemical attributes and the leaf content of nutrients coffee cultivars (Coffea arabica L.) under plant densities were evaluated in Adamantina, region of Alta Paulista, São Paulo state, Brazil, from May 1995 to February 2000. The coffee tree cultivars Yellow Catuaí (IAC 47) and Obatã (IAC 1669-20) (low height) and Acaiá (IAC 474-19) and Yellow Icatu (IAC 2944) (high height) were submitted to the populations of 2500, 5000, 7519 and 10000 plants per hectare with a coffee tree per hole row spacing with in of 1,0 m. The population of 2500 plants per hectare with two plants per hole was also studied. The treatments were the combinations between cultivars and populations arranged in a randomized complete blocks design with tree replications and the plots as the populations and the subplots as the cultivars. The NPK fertilizations by area were distributed equally among the plants in each treatment. Liming was not made after the planting of coffee. The three-year coffee production per area and per plant was higher in low height cultivars, which did not differ among themselves. Increasing the population of coffee caused increased production of coffee by area and reduced production per plant. The production of a coffee tree was higher in the holes with a plant. Five years after planting the soil of coffee cultivars differ in contents of organic matter, calcium and potassium, respectively, in sections 0-20 and 20-40 cm, 0-20 cm and 20-40 cm and were similar in the others soil chemicals attributes. In sections 0-20 cm and 20-40 cm of soil and Yellow Catuaí and Yellow Icatu organic matter increased with the population of these cultivars and was higher in the soil with two coffees per hole. The increase in population density resulted in the 20-40 cm section of soil greater content of calcium and magnesium and higher values of sum of bases... (Complete abstract click electronic access below)
240

Atributos químicos do solo e estado nutricional de cafeeiros em diferentes densidades populacionais /

Paulo, Edison Martins. January 2008 (has links)
Orientador: Enes Furlani Junior / Banca: Orivaldo Arf / Banca: Edson Lazarini / Banca: José Laércio Favarin / Banca: Heitor Cantarella / Resumo: A produção trienal de café, os atributos químicos do solo e o teor foliar dos macronutrientes em cultivares de cafeeiro (Coffea arabica L.) sob diferentes densidades de plantio foram avaliados em Adamantina, município situado na região da Alta Paulista (SP), entre maio de 1995 e fevereiro de 2000. As cultivares de café Catuaí Amarelo (IAC 47) e Obatã (IAC 1669- 20), de porte baixo, e Acaiá (IAC 474-19) e Icatu Amarelo (IAC 2944), de porte alto foram estabelecidas em covas com uma planta, distanciadas por 1,0 m entre si na linha de plantio, nas densidades populacionais de 2500, 5000, 7519 e 10000 plantas por hectare. A população de 2500 plantas por hectare com duas plantas por cova também foi estudada. Adotou-se o delineamento estatístico de blocos ao acaso com três repetições, com parcelas subdivididas, correspondendo às parcelas as populações e às subparcelas as cultivares. A adubação recomendada por área foi distribuída igualmente entre as plantas de cada tratamento. A calagem não foi feita após o plantio dos cafeeiros. A produção trienal de café por área e por planta foi maior nos cafeeiros de porte baixo, que não diferiram entre si. O aumento da população de cafeeiros causou maior produção trienal de café por área e diminuição da produção por planta. Os cafeeiros das covas com duas plantas produziram mais café. Cinco anos após o plantio os solos das cultivares de cafeeiro diferiram nos teores de matéria orgânica, de cálcio e de potássio, respectivamente nas camadas 0-20 e 20-40 cm, 0-20 cm e 20-40 cm, e foram semelhantes nos demais atributos químicos do solo. Nas camadas 0-20 cm e 20-40 cm dos solos da Icatu Amarelo e Catuaí Amarelo a matéria orgânica aumentou com a população dessas cultivares e foi maior nos solos com dois cafeeiros por cova. O aumento da densidade populacional resultou na camada 20-40 cm do solo maiores teores ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The triennial production of coffee, the soil chemical attributes and the leaf content of nutrients coffee cultivars (Coffea arabica L.) under plant densities were evaluated in Adamantina, region of Alta Paulista, São Paulo state, Brazil, from May 1995 to February 2000. The coffee tree cultivars Yellow Catuaí (IAC 47) and Obatã (IAC 1669-20) (low height) and Acaiá (IAC 474-19) and Yellow Icatu (IAC 2944) (high height) were submitted to the populations of 2500, 5000, 7519 and 10000 plants per hectare with a coffee tree per hole row spacing with in of 1,0 m. The population of 2500 plants per hectare with two plants per hole was also studied. The treatments were the combinations between cultivars and populations arranged in a randomized complete blocks design with tree replications and the plots as the populations and the subplots as the cultivars. The NPK fertilizations by area were distributed equally among the plants in each treatment. Liming was not made after the planting of coffee. The three-year coffee production per area and per plant was higher in low height cultivars, which did not differ among themselves. Increasing the population of coffee caused increased production of coffee by area and reduced production per plant. The production of a coffee tree was higher in the holes with a plant. Five years after planting the soil of coffee cultivars differ in contents of organic matter, calcium and potassium, respectively, in sections 0-20 and 20-40 cm, 0-20 cm and 20-40 cm and were similar in the others soil chemicals attributes. In sections 0-20 cm and 20-40 cm of soil and Yellow Catuaí and Yellow Icatu organic matter increased with the population of these cultivars and was higher in the soil with two coffees per hole. The increase in population density resulted in the 20-40 cm section of soil greater content of calcium and magnesium and higher values of sum of bases... (Complete abstract click electronic access below) / Doutor

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