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Use of triple beam resonant gauges in torque measurement transfer standardIntiang, Jittakant January 2010 (has links)
A new torque transfer standard using metallic TBTF resonant sensor was developed to overcome the overload capability problem which occurs with conventional metallic resistance strain gauges. Previous research work, however, has shown that the first prototype of the metallic TBTF resonant sensor was not suitable for use in a torque transfer standard due to its size and subsequent sensitivity to parasitic lateral forces. To maximize the benefits from this sensor, particularly overload capability and long-term stability, in the high accuracy torque measurement application area, there is a need to develop significantly smaller devices. The aim of this thesis is to research through FEA modelling and experimental characterisation the key performance parameters required to produce a miniaturised metallic TBTF resonant sensor that provides better performance when applied in a torque measurement system. For high accuracy any torque transducer using these sensors ought to have low sensitivity to parasitic influences such as bending moments and lateral forces, which can only be achieved with reduced size. The problems with the existing design, key design issues, possible configuration and packaging solutions of the metallic TBTF resonant sensor that could be used for achieving a higher accuracy torque transfer standard are considered. Two designs of miniaturised metallic TBTF resonant sensors, SL20 and SL12, are considered and experimentally investigated. The lateral forces are reduced by 52% for SL20 design and by 80% for SL12 design when compared to the original SL40 design. A torque transducer using the SL20 design was calibrated falling into the Torque Transfer Standard class of accuracy 1 category, uncertainty 0.8%. A torque transducer using the SL12 design was made and calibration showed a class of accuracy 0.5 category, uncertainty 0.2%. The results from this research indicate that the SL12 design is suitable for use in a torque transfer standard. The SL12 design is optimal and the smallest size possible based on the overload capability design criteria requiring the tine cross sectional area to remain constant.
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Ablation of cardiac myosin binding protein-C disrupts the super-relaxed state of myosin in murine cardiomyocytesMcNamara, James W., Li, Amy, Smith, Nicola J., Lal, Sean, Graham, Robert M., Kooiker, Kristina Bezold, van Dijk, Sabine J., Remedios, Cristobal G. dos, Harris, Samantha P., Cooke, Roger 05 1900 (has links)
Cardiac myosin binding protein-C (cMyBP-C) is a structural and regulatory component of cardiac thick filaments. It is observed in electron micrographs as seven to nine transverse stripes in the central portion of each half of the A band. Its C-terminus binds tightly to the myosin rod and contributes to thick filament structure, while the N-terminus can bind both myosin S2 and actin, influencing their structure and function. Mutations in the MYBPC3 gene (encoding cMyBP-C) are commonly associated with hypertrophic cardiomyopathy (HCM). In cardiac cells there exists a population of myosin heads in the super-relaxed (SRX) state, which are bound to the thick filament core with a highly inhibited ATPase activity. This report examines the role cMyBP-C plays in regulating the population of the SRX state of cardiac myosin by using an assay that measures single ATP turnover of myosin. We report a significant decrease in the proportion of myosin heads in the SRX state in homozygous cMyBP-C knockout mice, however heterozygous cMyBP-C knockout mice do not significantly differ from the wild type. A smaller, non-significant decrease is observed when thoracic aortic constriction is used to induce cardiac hypertrophy in mutation negative mice. These results support the proposal that cMyBP-C stabilises the thick filament and that the loss of cMyBP-C results in an untethering of myosin heads. This results in an increased myosin ATP turnover, further consolidating the relationship between thick filament structure and the myosin ATPase. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.
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Oxydes sans plomb pour la détection de gaz : OSPÉGAZ / Lead-free oxides for gas detection : OSPÉGAZEl Romh, Mohamad Ali 01 July 2016 (has links)
La détection de gaz, qui utilise aujourd'hui principalement des capteurs optiques, des capteurs électrochimiques à base de plomb et des capteurs catalytiques est un marché très porteur (estimé à 3 milliards d'euros) et doté d'une forte croissance (10% par an). La nécessité de développer de nouveaux systèmes d'instrumentation dédiés à la surveillance de la qualité de l'air intérieur et à la détection de substances dangereuses implique l'étude et le développement de nouveaux capteurs élaborés à partir de produits compatibles avec les enjeux environnementaux (RoHs, REACH), et économiques (matériaux à faible coût, techniques de réalisation fiables, durée de vie élevée). Le projet ANR OSPÉGAZ (Oxydes sans plomb pour la détection de gaz) vise à développer des systèmes d'instrumentations intégrés innovants dédiés à la caractérisation des différentes expositions environnementales en lien notamment avec les actions recommandées dans le cadre du PNSE2 pour les impacts sanitaires avérés. Le travail de thèse présenté dans ce manuscrit fait partie du projet OSPÉGAZ. L'objectif du travail a été, d'une part, de mettre au point un nouveau procédé d'élaboration d'encre au sein du laboratoire UDSMM pour l'élaboration et la caractérisation de films épais poreux, et d'autre part, de réaliser des capteurs de gaz à base de ces films. Nous avons choisi d'utiliser le matériau BaTiO₃, bien connu de la littérature, comme matériau de départ afin de mettre au point le procédé d'élaboration de couches épaisses. Par la suite, nous avons choisi le BaSrTiFeO₃ comme matériau sensible au gaz, et nous avons étudié deux compositions correspondant à deux taux de fer : Ba₀.₈₅Sr₀.₁₅Ti₀.₉Fe₀.₁O₃ (BSTF 10%) et Ba₀.₈₅Sr₀.₁₅Ti₀.₉₈Fe₀.₀₂O₃ (BSTF 2%). Ces matériaux ont été caractérisés dans une large gamme de fréquence (100 Hz à 1 MHz) et de température (25°C à 500°C). Les propriétés diélectriques en fonction de la fréquence et de la température ont été étudiées sur deux structures différentes d'électrodes : capacité parallèle (MIM) et capacité interdigitée (CID). Enfin, des démonstrateurs de capteurs de gas basés sur le principe des capteurs semi-conducteurs, ont été réalisés à partir de films épais poreux (BT, BST, BSFT 10% et 2%). Ces démonstrateurs ont été testés dans les locaux de la société SIMTRONICS sous différents gaz comme le monoxyde de carbone CO (200ppm), le sulfure d'hydrogène H₂S (50ppm) et le dioxyde de soufre SO₂ (20ppm) à 400°C et 450°C. Sous H₂S (50ppm), ils ont montré une plus grande sensibilité relative du BSTF (10%) (55.4%) par rapport au BSTF (2%) (48%) à 450°C. La bonne sensibilité relative et la réponse dynamique très intéressante montrent que le matériau BSTF dispose d'un potentiel très intéressant pour la détection de gaz. L'optimisation de la géométrie des capteurs, du taux de fer et de la température de fonctionnement devrait nous permettre d'améliorer les performances de nos démonstrateurs. / Today gas detection, which now mainly uses optical sensors, electrochemical sensors based on lead, and catalytic sensors, is a very promising market (estimated at 3 billion euros) with a strong growth (10% per year). The need for new instrumentation systems dedicated to the monitoring of the air quality and to the detection of hazardous substances, requires the study and development of new sensors compatible with the European environmental standards : Restriction of the use of Hazardous Substances (RoHS) ; Registration, Evaluation and Authorization of Chemicals (REACh). The OSPÉGAZ project aims to develop innovative integrated instrumentations systems for the characterization of different environmental exposures linked to the actions recommended by the PNSE2 for proven health impacts. Our research project aims to develop innovating and cost-effective gas sensors containing lead-free oxides and dedicated to the detection of flammable gases and protection against toxic risks. The works of the thesis presented in this manuscript is a part of this project. The objectives were, firstly, to develop a new process for ink preparation in UDSMM laboratory, for the elaboration, electrical and physicochemical characterizations, of thick porous film, and secondly to make gas sensors based on these films. We chose to use the BaTiO3 (well-known material in literature) material as a first material in order to develop the process of thick film elaboration. After that, we chose the BaSrTiFeO₃ as gas-sensitive material, and we studied two compositions of Ba₁₋ ₓ Sr ₓ Ti₁₋yFeyO₃ with two different concentrations or iron : Ba₀.₈₅Sr₀.₁₅Ti₀.₉Fe₀.₁O₃ (BSTF 10%) and Ba₀.₈₅Sr₀.₁₅Ti₀.₉₈Fe₀.₀₂O₃ (BSTF 2%). Electrical characterizations were made in a wide range of frequency (100 HZ to 1 MHz) and temperature (25° C to 500° C). The dielectric properties as a function of temperature and frequency were studied using two different structures of capacitance : metal-insulator-metal (MIM) and interdigital electrodes (CID). Finally we have developed semi-conductor gas sensors based on BT, BST and BSTF (10% ; 2%) thick films. All our sensors were tested under different gases such as carbon monoxide CO (200ppm), hydrogen sulphide H₂S (50ppm) and sulfur dioxide SO₂ (20ppm), at various temperature, in the laboratory of SIMTRONICS SAS. We have measured the greatest relative sensitivity under H₂S (50ppm) gas ; 55.4% and 48% respectively for BSTF (10%) and BSTF (2%), at 450°C. Good relative sensitivity and very interesting dynamic responsesof BSTF show that the material has a great potential for the detection of gas. The optimization of the sensor geometry, iron rate and operating temperature should allow us to improve the performance of our demonstrators.
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Síntese e caracterização do sistema nanoestruturado Sr1-XLaxTi1-yFeyO3: Aplicação como sensor de gás / Synthesis and characterization of nanostructured system Sr1-XLaxTi1-yFeyO3: application as gas sensorEscanhoela Júnior, Carlos Augusto 07 May 2015 (has links)
Os materiais de estrutura perovskita compreendem um vasto grupo de compostos cuja estrutura na sua forma mais simples pode ser representada pela fórmula química ABO3. Uma das principais vantagens que a estrutura perovskita apresenta é o alto grau de flexibilidade em acomodar uma grande variedade de átomos nos sítios A e B, permitindo um maior controle de suas propriedades físicas e químicas bem como a manutenção de sua estrutura básica, mesmo para altas concentrações de átomos substituintes. Devido estas propriedades, estes materiais têm sido aplicados com sucesso como capacitores, varistores, fotoeletrodos, memóriasferroelétricas e sensores de gases. Nas últimas décadas, tem sido reportada a utilização do titanato de estrôncio (SrTiO3, ST) na forma de filmes finos e espessos como sensor de gás oxigênio em altas temperaturas (>500 °C). Recentemente, foi mostrado que o titanato de estrôncio dopado com Fe apresentava uma excelente sensibilidade ao gás ozônio. Entretanto, neste trabalho, somente uma composição foi caracterizada e nem todas as propriedades importantes em relação a esta aplicação foram completamente exploradas. Neste contexto, esta tese de doutorado teve como objetivo verificar o efeito da substituição do átomo de estrôncio pelo lantânio e do titânio pelo Ferro no composto SrTiO3 na forma de pó e filmes finos nanoestruturados com a finalidade de verificar o efeito destas substituições nas propriedades sensoras do material. Inicialmente, com o objetivo de avaliar a influência da adição de La na estrutura do composto ST, amostras na forma de pó do sistema Sr1-xLaxTiO3.(SLT) foram preparadas através do método dos precursores poliméricos. Posteriormente, pelo mesmo método, foram sintetizadas amostras do sistema SrTi1-xFexO3 (STF) e Sr1-XLaxTi1-yFeyO3 (SLTF). A partir das amostras na forma de pó e na forma de solução, filmes finos e espessos foram respectivamente obtidos através das técnicas de deposição por feixe de elétrons (EBD) e spin-coating (SC). As amostras nanoestruturadas na forma de pó e na forma de filmes foram caracterizadas por difração de raios X, espectroscopia de absorção de raios X (XANES) na borda K do Ti e do Fe e espectroscopia de fotoelétrons excitados por raios X (XPS). A análise morfológica foi realizada através das técnicas de microscopia eletrônica de varredura (MEV) e microscopia de força atômica (MFA). As amostras do sistema STF e SLTF na forma de filmes finos foram avaliadas em relação à sensibilidade aos gases O3, NO2, NH3 e CO. Os resultados indicaram que os filmes do sistema SLTF depositados pela técnica de deposição por feixe de elétrons apresentam uma maior sensibilidade ao gás ozônio, enquanto o filme de mesma composição depositado pelo método de spin-coating apresentou uma melhor estabilidade e tempo de recuperação em relação a este mesmo gás. / The perovskite structure materials comprise a large group of compounds with the structure in simple form can be represented by the ABO3. chemical formula. The main advantage that the perovskite structure presents is the high degree of flexibility to accommodate a wide variety of atoms in sites A and B, allowing a greater control of physical and chemical properties of the material, maintaining its structure even for a high concentrations of substituent\'s. Due to these properties, these materials have been successfully applied as capacitors, varistors, photoelectrodes, ferroelectric memories and gas sensors. In the last decade, strontium titanate (SrTiO3, ST) in the form of thin and thick films have been reported as oxygen gas sensor at higher temperatures (> 500 °C). Recently, strontium titanate doped with Fe was used as the first ozone sensor. However, the work was carried out only with a certain composition and some important properties for this application have not been fully exploited. In this context, this PhD thesis aimed to the synthesis of strontium titanate system in powder form and nanostructured thin films with the substitution of Sr for La and Ti for Fe. In order to verify the effect of these substitutions in material properties initially Sr1-xLaxTiO3 (SLT) samples were prepared in powder form by the polymeric precursor method in order to evaluate the influence of the addition of La in the structure of the compound ST. Subsequently, samples were synthesized from SrTi1-x Fex O3 (STF) and Sr1-XLaxTi1-yFeyO3 (SLTF) systems through the polymeric precursors, which were used for the deposition of thin and thick films, which were respectively obtained through electron beam deposition techniques (EBD) and spin-coating (SC). Samples in the form of nanostructured powder and thin films were characterized by X-ray diffraction, X-ray absorption spectroscopy (XANES) at Ti and Fe K-edges and by X-ray photoelectron spectroscopy (XPS). Morphological analysis was performed using the scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The STF and SLTF samples in a thin film form were evaluated towards their sensitivity to O3, NO2, NH3 and CO gases. The results indicated that SLTF films deposited by electron beam deposition technique exhibit higher sensitivity to ozone gas. However the same composition deposited by spin-coating showed a better stability and recovery time relative to the same gas.
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[en] FORMULATION OF AXISYMMETRIC THICK SHELLS EMPLOYING ENRICHED FINITE ELEMENTS / [pt] FORMULAÇÃO DE CASCAS ESPESSAS AXISSIMÉTRICAS UTILIZANDO ELEMENTOS FINITOS ENRIQUECIDOSHARRY GUSTAVO SAAVEDRA ESPINOZA 15 April 2004 (has links)
[pt] Nesta dissertação apresenta-se uma formulação para a
análise numérica de cascas espessas axissimétricas, sob
os carregamentos de pressão e força distribuida ao longo
de um paralelo, utilizando-se a técnica de elementos
finitos enriquecidos. As discretizações dos campos de
deslocamento axial e radial são consideradas no domínio
do elemento verificando-se as seguintes restrições:
tensões nulas nas faces interna e externa da casca e uma
combinação das soluções analíticas para cascas espessas
cilíndricas e esféricas. A formulação resulta em um
modelo com seis graus-de-liberdade generalizados por
ponto nodal para elementos unidimensionais, considerando-
se como referencia a superfície média da casca. Na
imposição de condições de continuidade e de fixação
associados aos graus-de-liberdade empregou-se o método de
penalidades. A formulação foi implementada e alguns
testes numéricos são apresentados para demonstrar sua
aplicabilidade em comparações com outras soluções
analíticas ou numéricas. / [en] This work presents an element formulation for the analysis
of axisymmetric thick shells under pressure and line loads
using Enriched Finite Element technique. Axial and radial
displacement fields are considered in the formulation
under the conditions of zero stresses at internal and
external surfaces of the shell and, a combination of
analitical solutions for radial displacements of
cilindrical and spherical thick wall shells. The
formulation results in a six generalized degree-of-freedom
uni-dimensional model refered to the element nodal points
at the shell mid-surface. Continuity between adjoining
elements and clamped boundary conditions associated to the
element degrees-of-freedom are imposed by the use of a
penalty method. The formulation has been implemented and
some numerical analysis results are shown to demonstrate
its aplicability, as compared to other analytical or
numerical solutions.
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Rôle des claudines dans les jonctions serrées de la branche large ascendante corticale de l’anse de Henle / Role of claudins in thick ascending limb of Henle’s loopFiguères, Marie-Lucile 22 September 2017 (has links)
Les claudines sont des protéines des jonctions serrées qui déterminent la perméabilité ionique paracellulaire. La branche large ascendante corticale de l’anse de Henle (cBLAH) exprime plusieurs claudines (en particulier claudine-10b, -14, -16 et -19). Les mutations inactivatrices des claudines-16 et -19 sont responsables du syndrome FHHNC chez l’Homme, caractérisé par une perte de calcium et de magnésium par un défaut de réabsorption dans la BLAH. En l’absence de modèle in vitro adapté, les fonctions des claudines dans la cBLAH restent méconnues, ainsi que l’action des déterminants de la réabsorption du calcium et du magnésium qui y sont exprimés : récepteur de la PTH (PTH1R) et Casr. L’objectif de ce travail était de contribuer à combler ces lacunes. Nous avons montré que la claudine-16 était requise pour une perméabilité paracellulaire aux cations divalents normale dans la cBLAH murine, grâce à l’étude des souris claudine-16-/-. La claudine-16 n’affecte pas les autres perméabilités ioniques, ce qui est concordant avec le phénotype d’inactivation de la claudine-16 chez l’Homme. En condition basale, la claudine-14 est indétectable. Les flux calciques ne sont pas augmentés chez les souris claudine-14-/-. Nous avons décrit le premier cas de mutation inactivatrice de la claudine-10b chez l’Homme, à l’origine d’un syndrome de Bartter et de déficits de sécrétion salivaire et sudorale et conclu que la claudine-10 augmente la perméabilité paracellulaire au sodium. Nous avons également étudié le rôle de Casr et du récepteur de la PTH (PTH1R) dans le contrôle de la perméabilité ionique de la cBLAH murine. La stimulation de la réabsorption du calcium par l’inhibition du Casr ou l’activation du PTH1R ne nécessite pas la présence de la claudine-16. En revanche, la claudine-16 est nécessaire pour le contrôle de la réabsorption de magnésium par ces deux déterminants. Ces résultats sont en faveur d’un contrôle séparé des absorptions de calcium et magnésium, et remettent en cause le concept du rôle central de claudine-14. Notre projet nous a également permis de décrire un nouveau mécanisme d’atteinte des jonctions serrées, d’origine auto-immune, par anticorps anti-claudine-16 chez un patient. Si l’origine de cette atteinte est inconnue, ce modèle soulève de nouvelles questions sur les conséquences de l’inactivation de la claudine-16 dans la BLAH, le phénotype du patient étant différent du syndrome FHHNC (absence de néphrocalcinose en particulier). Ce travail nécessite d’être complété par une étude plus approfondie des mécanismes contrôlant la fonction des claudines en réponse au calcium et au magnésium extracellulaires et à la PTH. / Claudins are integral membrane proteins expressed at tight junctions, which determine paracellular permeability to ions. The thick ascending limb of the loop of Henle (TALH), expresses several claudins (including claudin-10b, -14, -16, -19). Inactivating mutation of claudin-16 and -19 cause familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC), a renal tubular disorder featuring a severe defect in paracellular divalent cation transport in the TALH. Due to the lack of appropriate study model, both the function of claudins and the role of potential regulatory factors, such as the PTH receptor PTH1R and the calcium receptor CaSR, are only partially known. The purpose of the study was to contribute to fill this gap. We studied several models of claudin inactivation (claudin-16-/- and claudin-14-/- mice, human inactivating mutation of claudin-10b). We demonstrated that claudin-16 was required for normal paracellular permeability to calcium and magnesium in the TALH, but did not affect the permeability to other ions; this was consistent with the known features of FHHNC syndrome. In basal conditions, claudin-14 is not detectable and calcium reabsorption is not increased in claudin-14-/- mice. We described the first inactivating mutation of claudin-10b in Humans, causing a Bartter syndrome and defects in sweat and saliva secretions; we concluded that claudin-10b increases paracellular permeability to sodium. We studied the role of Casr and PTH1R, as determinants of paracellular permeability in the mouse TALH. Casr inactivation or PTH1R activation could increase calcium absorption in the absence of Claudin-16. By contrast, both conditions did not change magnesium transport in the absence of Claudin-16. These results suggest that calcium and magnesium absorptions can be differentially controlled in the TALH; in addition, they challenge the hypothesis of a central role of Claudin-14. Finally, we described for the first time an autoimmune disease affecting tight junction in the TALH, due to anti-claudine-16 autoantibody. The phenotype of this patient differed from that of patients with FHHNC syndrome (no nephrocalcinosis) and raised new questions about the pathogenesis of claudin-16 inactivation. More data on the effect of extracellular calcium and magnesium, PTH1R and Casr on the function of tight junction in the TALH are warranted.
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Micromoulage de films épais de Sm-Co / Micromoulding of Sm-Co thick filmsChouarbi, Katia 21 February 2013 (has links)
Cette étude a été motivée par les nombreux avantages du procédé de micromoulage, qui couple la croissance électrolytique et la localisation du film avec un moule en résine épaisse. Ce procédé permet en effet la réalisation de micro-objets, dont les dimensions sont uniquement dépendantes de la résolution des techniques de lithographie employées pour définir les moules en résine. Le micromoulage permet donc de réaliser des microstructures métalliques et est compatible avec la technologie MEMS. Nous avons mis en évidence l’influence de différents paramètres expérimentaux dans le cadre de l’étude de la croissance électrolytique du samarium-cobalt en solution aqueuse dans une cellule de Hull. Cette étude nous a permis de déterminer plusieurs points de fonctionnement conduisant à des teneurs en samarium et des épaisseurs élevées : jusqu'à 50 % de samarium et plusieurs microns d’épaisseur. En outre, un certain nombre d’hypothèse ont été émises, qui lient le procédé d’élaboration et le mécanisme de croissance. Nous avons aussi réussi a montré qu’il est possible de réaliser des micromotifs de plusieurs microns d’épaisseur contenant un rapport Sm/(Sm+Co) relativement élevé (10 %) et une faible contamination en oxygène (8 %). / This study was motivated by the advantags of micromolding process, which couples the electrolytic growth and location of the film with a thick resin mold. This method makes it possible the achievement of micro-objects, the dimensions of which are only dependent on the resolution of the lithographic techniques used to define the resin molds. The micromolding can therefore produce metal microstructures and is compatible with MEMS technology. We have highlighted the influence of various experimental parameters in the context of the study of the electrolytic growth of samarium-cobalt in aqueous solution in a Hull cell. this study allowed us to identified several operating points resulting in samarium contents and high thicknesses up to 50% of samarium and several microns thick. In addition, a number of hypotheses have been put forward, which link the process of development and growth mechanism. We also successfully showed that it is possible to create micropatterns of several microns thick report containing Sm / (Sm + Co) relatively high (10%) and low oxygen contamination (8%).
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Alkoholna fermentacija melase i gustog soka šećerne repe pomoću imobilisanih ćelija Saccharomyces cerevisiae / Alcoholic fermentation of sugar beet molasses and thickjuice by immobilized Saccharomyces cerevisiae cellsVučurović Vesna 07 September 2012 (has links)
<p>Proizvodnja bioetanola iz među- i nusproizvoda procesa<br />prerade šećerne repe, može imati pozitivan uticaj na<br />regionalnu ekomomiju i socio-ekonomski razvoj u zemljama<br />sa razvijenom industrijom konzumnog šećera, kao što je<br />Srbija. Kao proizvodni mikroorganizam u proizvodnji<br />etanola u najvećoj meri se koristi kvasac Saccharomyces<br />cerevisiae. Primena imobilisanih ćelija kvasca u fermentaciji<br />podloga sa visokom sadržajem šećera (iznad 250 g/l), tzv.<br />VHG fermentacija, je često izučavana sa ciljem povećanja<br />efikasnosti proizvodnje etanola. U ovom radu su ćelije S.<br />cerevisiae imobilisane na različitim novim nosačima:<br />presovanim rezancima šećerne repe (PRŠR), suvim<br />rezancima šećerne repe (SRŠR), parenhimskom tkivu stabla<br />kukuruza (PTSK) u obliku diska, na kombinovanim<br />nosačima od PTSK u obliku diska obloženog Ca-alginatom(K1) i ispunjenog Ca-aglinatom (K2), na kuglicama Caalginata(AB) kao i na kombinovanim kuglicama od Caalginata i mliva PTSK (ABC). Imobilisane ćelije kvasca su primenjene za fermentaciju melase i gustog soka šećerne repe sa krajnjim ciljem da se racionalnim korišćenjem</p><p>među- i nusproizoda procesa prerade šećerne repe postigne<br />efikasna proizvodnja etanola uz smanjene troškove<br />proizvodnje kao, i uz smanjenje emisije otpadnih tokova.<br />U radu je ustanovljeno da su PRŠR, SRŠR i PTSK efikasni<br />nosači za imobilizaciju ćelija kvasca zahvaljujući prisustvu<br />pozitivno naelektrisanih funkcionalnih grupa, visokoj<br />poroznosti, hidrofilnosti, mehaničkoj čvrstini i stabilnosti.<br />Takođe ovi nosači štite kvasac od osmotskog stresa,<br />toksičnog dejstva etanola i inhibitora. Zahvaljujući<br />heterogenoj strukturi PRŠR, SRŠR i PTSK se mogu koristiti<br />kao efikasni adsorbenti za ćelije kvasca, kao i za uklanjanje<br />katjonskih i anjonskih komponenata u postupku prerade<br />otpadnih voda. Pored toga, utvđeno je da PTSK predstavlja<br />alternativni obnovljivi izvor hranljivih materija neophodnih<br />kvascu tokom fermentacije melase i gustog soka, a takođe<br />deluje i kao antipenušavac. Primenom ćelija kvasca<br />imobilisanih na SRŠR ostvarena je maksimalna<br />produktivnost etanola od 1,48 g/lh za melasu i 1,57 g/lh za<br />gusti sok, pri početnoj koncentraciji šećera u podlozi 180 g/l.<br />Primenom ćelija kvasca imobilisanih na PTSK u obliku<br />diska (visine oko 5 mm i prečnika oko 20 mm) postignuta je<br />produktivnost etanola 1,26 g/lh za melasu 1,42 g/lh za gusti<br />sok, pri početnoj koncentraciji šećera 150 g/l. Osnovni<br />nedostatak primene imobilisanih ćelija na SRŠR i PTSK u<br />alkoholnoj fermentaciji je lako ispiranje ćelija sa nosača.<br />Kombinovani nosači u obliku diska PTSK obloženog Ca alginatom<br />(K1) i ispunjenog Ca-aglinatom (K2) su<br />pripremljeni kako bi se sprečilo ispiranje ćelija kvasca.<br />Utvrđeno je da nosač K1 nije adekvatan za povećanje<br />efikasnosti imobilizacije. Imobilizacijom kvasca punjenjem<br />nosača K2 je povećana efikasnost imobilizacije ćelija kvasca<br />na PTSK, ali je usled velike zapremine i kompaktnosti<br />nosača K2 tokom fermentacije delimično otežan transport<br />supstrata i produkata kroz disk.<br />Melasa i gusti sok šećerne repe su veoma dobre sirovine za<br />proizvodnju etanola, usled visokog sadržaja fermentabilnih<br />šećera, koji slobodne i/ili imobiliane ćelije S. cerevisiae mogu<br />direktno koristiti za fermentaciju. Međutim, uzimajući u<br />obzir hemijski sastav ovih sirovina i ostvarene parametre</p><p>fermentacije, utvrđeno je da je gusti sok bolja sirovina za<br />proizvodnju etanola od melase, posebno u VHG uslovima.<br />Takođe je utvrđeno da se gusti sok može koristiti kao<br />sirovina za fermentaciju bez dodataka hranljivih materija.<br />Ustanovljeno je da su melase koje preostaju nakon osmotske<br />dehidratacije crvenog kupusa i mrkve veoma dobre sirovine<br />za proizvodnju etanola pri početnoj koncentraciji šećera u<br />podlozi do 150 g/l, ali nisu pogodne sirovine za VHG<br />fermentaciju pomoću slobodnih i imobilisanih ćelija u AB<br />kuglicama. Fermentacijom melase nakon osmotske<br />dehidratacije kupusa i mrkve početne koncentracije šećera<br />125 g/l, primenom ćelija kvasca imobilisanih u AB<br />kuglicama, ostvarena je najviša produktivnost etanola od<br />1,24 g/lh i 1,30 g/lh. Tokom fermentacije melase i gustog soka<br />primenom ćelija kvasca imobilisanih u AB kuglicama usled<br />izdvajanja CO2, dolazi do narušavanja strukture kuglica<br />pojavom poprečne pukotine koja kuglicu polimera deli na<br />dva približno jednaka dela.<br />Kako bi se sprečila degradacija Ca-alginata tokom<br />fermentacije pripremljen je novi kombinovani nosač od Caalginata<br />i mliva PTSK (ABC). Dodatkom samlevenog PTSK<br />sa mikrostrukturom pčeljinjeg saća u Ca-alginat je povećana<br />poroznost kuglica čime je omogućen efikasniji prenos mase<br />supstrata i produkata, povećana je raspoloživa površina za<br />adsorpciju i rast ćelija kvasca kao i čvrstina i stabilost<br />kuglica. Poređenjem parametara fermentacije, utvrđeno je<br />da su ćelije kvasca imobilisane na ABC kuglicama efikasniji<br />biokatalizator u poređenju sa slobodnim ćelijama kvasca,<br />kao i u poređenju sa ćelijama imobilisanim u AB kuglicama.<br />Dodatkom samlevenog PTSK u podlogu ili u Ca-alginat<br />povećava se sadržaj etanola i metanola, smanjuje se sadržaj<br />kiselina i acetaldehida u sirovom destilatu, dok se sadržaj<br />viših alkohola, estara i furfurala ne menja značajno. Ćelije<br />kvasca imobilisane u kombinovanim ABC kuglicama se<br />mogu uspešno primeniti za pet ponovljenih fermentacija<br />gustog soka pri standardnim (NG) i uslovima visoke<br />koncentracije šećera (VHG) pri čemu se može postići<br />produktivnost etanola 1,92-2,30 g/lh. Primenom imobilisanih<br />ćelija kvasca u kombinovanim ABC kuglicama u<br />kontinualnoj VHG fermentaciji gustog soka, početne<br />koncentracije šećera 300 g/l, ostvaren je stabilan<br />fermentacioni sistem tokom 15 dana, pri čemu je<br />produktivnost etanola iznosila 3,29 do 4,66 g/lh.</p> / <p>Bioethanol production from intermediate and byproducts<br />of sugar beet processing has a beneficial scope<br />in view of the socio-economic development and regional<br />economy in countries with developed sugar industry,<br />such as Serbia. Saccharomyces cerevisiae strain is the<br />most widely used ethanol producing microorganism. To<br />increase the efficiency of ethanol production, many<br />process improvements including immobilized cells<br />application and fermentation of very high gravity (VHG)<br />media with initial sugar over 250 g/l, have been studied.<br />In the present work yeast S. cerevisiae was immobilized<br />onto different new carriers: pressed sugar beet pulp<br />(PSBP), dried sugar beet pulp (DSBP), maize stem<br />ground tissue (MSGT) disks, MSGT discs coated with<br />Ca-alginate (K1) and MSGT discs filled with Ca-alginate<br />(K2), Ca-alginate beads (AB) and combined beads made</p><p>of Ca-alginate and maize stem ground tissue meal (ABC).<br />Immobilized yeast cells were used for ethanol<br />fermentation of molasses and thick juice with purposes to<br />obtain efficient ethanol production, to lower high<br />operating costs and to achieve the zero-waste goal<br />through a rational use of by-products of sugar beet<br />processing.<br />In the present work it was found that PSBP, DSBP and<br />MSGT are efficient carriers for yeast cell immobilization<br />due to the presence of positively charged binding sites,<br />high porosity and hidrophylicity, good mechanical<br />strength and stability, while functioned as a fortification<br />against osmotic stress, toxins and inhibitors. It was also<br />found that due to the heterogeneous structure the PSBP,<br />DSBP and MSGT are promising adsorbents for the<br />removal of cationic and anionic compounds from<br />aqueous solutions in the waste water treatment. Besides,<br />it is found that the MSGT can be used as an alternative<br />nutrient source for yeast cells and as an anti foaming<br />agent. A maximum ethanol productivity of 1.48 g/lh and<br />1.57 g/lh was achieved in the fermentation of molasses<br />and thick juice (initial sugar of 180 g/l) using yeast<br />immobilized on DSBP. The highest values of ethanol<br />productivity, obtained in the case of using yeast<br />immobilized on MSGT discs as biocatalyst, for molasses<br />and thick juice (initial sugar of 150 g/l) fermentation<br />were 1.26 g/lh and 1.42 g/lh. The main disadvantage of<br />using DSBP and MSGT supported biocatalyst is intensive<br />leakage of yeast cells during the fermentation. In order to<br />prevent yeast leakage combined carriers in the form of<br />MSGT discs coated with Ca-alginate (K1) and MSGT<br />discs filled with Ca-alginate (K2) were prepared. The K1<br />carrier was found to be unsuccessful for improving yeast<br />immobilization efficiency, while the application K2<br />carrier improved yeast immobilization efficiency during<br />the fermentation. However, due to the large volume and<br />compactness of the K2 carrier substrate and product<br />mass transfer limitation were observed during the<br />fermentation.<br />The sugar beet molasses and thick juice are very good<br />raw materials for ethanol production due to high content<br />of fermentable sugars, which can be directly used for<br />fermentation by free and/or immobilized S. cerevisiae<br />cells without any modification. However, taking into</p><p>consideration quality of these raw materials and obtained<br />fermentation parameters, sugar beet thick juice was<br />found to be more suitable raw material for ethanol<br />fermentation, compared to molasses, particularly in the<br />VHG fermentation process and can be used without any<br />nutrient supplementation. Similarly, it was found that<br />molasses left after the osmotic dehydratation of red<br />cabbage (M1) and carrots (M2) are excellent raw<br />materials for ethanol fermentation of media with initial<br />sugar concentration up to 150 g/l, while they are not<br />convenient for VHG fermentation by free or immobilized<br />yeast cells in AB carrier. Maximum ethanol productivity<br />obtained at the end of fermentation of molasses M1 and<br />M2 by immobilized yeast in AB carrier was 1.24 g/lh and<br />1.30 g/lh, respectively. The release of CO2 during the<br />fermentation of molasses and thick juice by yeast cells<br />immobilized in the AB, lead to breakage of polymer<br />beads on two halves.<br />In order to prevent AB disruption, a new combined yeast<br />carrier (ABC) was developed by the addition of MSGT<br />meal into the Ca-alginate. It was found that the addition<br />of MSGT meal, with honeycomb microstructure,<br />provided large surface area for yeast cell attachment and<br />biofilm growth, and also increased alginate matrix<br />porosity, enabling better mass transfer characteristic,<br />better physical strength and stability of beads. The<br />highest values of fermentation parameters were obtained<br />in the fermentation system with yeast immobilized on<br />ABC carrier in comparison with free yeast cells and yeast<br />immobilized on AB carrier. The Ca-alginate and medium<br />supplementation with MSGT meal significantly increased<br />ethanol and methanol content, decreased acetaldehyde<br />and acetic acid content of the distillate, but did not affect<br />fusel alcohol, ester and furfural content of the distillate.<br />Repeated batch normal gravity (NG) and very high<br />gravity (VHG) ethanol fermentation of thick juice by<br />yeast immobilized on ABC carrier was successfully<br />carried out for at least five successive cycles without any<br />significant decrease in ethanol productivity which was in<br />the range 1.92-2.30 g/lh. Continuous VHG ethanol<br />fermentation of thick juice (initial sugar of 300 g/l) using<br />yeast immobilized on ABC was stable for at least 15 days<br />while achieved ethanol productivity was 3.29-4.66 g/lh.</p>
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Metoder för att undersöka effekterna av naturvårdshänsynen i skogsbruket, efter den senaste skogsvårdslagenMetoder för att undersöka effekterna av naturvårdshänsynen i skogsbruket, efter den senaste skogsvårdslagen.Persson, Alexandra January 2010 (has links)
<p>In 1994 a new Forestry Act was accepted in Sweden. One of the aims of the law is to raise consideration forpreservation of biodiversity. Since the new law got accepted and some time has passed, there now lie someinterest in examining whether the law has been effective towards its purpose. Methods suitable for analysishave been examined during this study. The content of this pilot study is based around five parameters whichcan be used to validate the effects of the new law. The field study were executed in Orsa, Dalarna, Sweden ina managed forest where last clearcut was performed after 1994. The work consisted of measuring theparameters specified and comparing the results to reference data from before 1994. The parameters benefit tothe preservation of biodiversity is discussed in the report aswell as the differences between the Forestry Actfrom 1994 and the previous one. The parameters examined in this study were standing dead wood, treespecies, thick big trees, trees with cavities/cavernous trees and smaller areas saved for preservation. All ofthese plus a few other variables are being considered in the 30 § of the Forestry Act of 1994. The reportimplied that the variables had a positive effect on the preservation of biodiversity, and possible to beinvestigated within the restrictions of this study, seemed to have increased. Due to the size of the forest beingsmall and reference data for some parameters missing or covering larger areas, one must be careful wheninterpreting the results.In 1994 a new Forestry Act was accepted in Sweden. One of the aims of the law is to raise consideration forpreservation of biodiversity. Since the new law got accepted and some time has passed, there now lie someinterest in examining whether the law has been effective towards its purpose. Methods suitable for analysishave been examined during this study. The content of this pilot study is based around five parameters whichcan be used to validate the effects of the new law. The field study were executed in Orsa, Dalarna, Sweden ina managed forest where last clearcut was performed after 1994. The work consisted of measuring theparameters specified and comparing the results to reference data from before 1994. The parameters benefit tothe preservation of biodiversity is discussed in the report aswell as the differences between the Forestry Actfrom 1994 and the previous one. The parameters examined in this study were standing dead wood, treespecies, thick big trees, trees with cavities/cavernous trees and smaller areas saved for preservation. All ofthese plus a few other variables are being considered in the 30 § of the Forestry Act of 1994. The reportimplied that the variables had a positive effect on the preservation of biodiversity, and possible to beinvestigated within the restrictions of this study, seemed to have increased. Due to the size of the forest beingsmall and reference data for some parameters missing or covering larger areas, one must be careful wheninterpreting the results.</p>
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Non-cognitivism and thick moral conceptsBlomberg, Olle January 2006 (has links)
<p>Enligt ett argument mot nonkognitivismen som många kritiker hänvisat till, så är denna teori oförenlig med förekomsten av så kallade ‘tjocka moraliska begrepp’. Argumentet har dock aldrig artikulerats och preciserats ordentligt, vilket lett till att det ofta misstolkats av både anhängare och kritiker av nonkognitivismen. I uppsatsen rekonstrueras och utvärderas argumentet såsom det formulerats av John McDowell. Enligt argumentet är nonkognitivismen bristfällig eftersom den inte både kan ge en tillfredsställande analys av tjocka moraliska begrepp och framställa moralisk argumentation och debatt som rationell. Uppsatsen visar dock att nonkognitivister kan undvika denna slutsats på flera sätt. Uppsatsen innehåller även en översikt över olika nonkognitivistiska perspektiv på tjocka moraliska begrepp.</p> / <p>Many critics of non-cognitivism have argued that the existence of ‘thick moral concepts’ constitutes a serious challenge to non-cognitivist views of moral language. While this argument is frequently invoked, it has never been clearly articulated. Hence, the argument is often misinterpreted by both friends and foes of non-cognitivism. In this thesis, John McDowell’s forceful rendering of the argument is reconstructed and evaluated. According to the argument, non-cognitivism is not an adequate metaethical view because it cannot both provide an adequate analysis of thick moral concepts and construe moral discourse as rational. It is argued in this thesis that there are several ways in which non-cognitivists can avoid this conclusion. The thesis also contains a survey of various non-cognitivist views on thick moral concepts.</p>
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