999 resultados para biofuel properties


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Now when the technology fast developing it is very important to control the formation of materials with better properties. In the scientific literature there is a number of works describing the influence of magnetic field on the properties and process of formation of materials. The goal of this master's thesis is to analyze the process of electrochemical synthesis of niobium oxide in the present of magnetic field, to compare properties of formed oxide films and to estimate the influence of magnetic field on the process and on the result of synthesis.

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Considered as a remedy to multiple problems that our world is facing, biofuels are nowadays promoted on a global scale. Despite this globalised approach, however, biofuels are heavily contested. Not only the social implications of biofuels are disputed and uncertain, particularly in countries of the global South, but also their environmental and economic rationales. Given these huge controversies, policies promoting biofuels would seem difficult to maintain. Yet, support for them has been surprisingly well established on the political agendas. With the aim of understanding this puzzle, this study asks how the dominant approach to biofuels has been sustained on a global level. In order to answer this question, the meanings and assumptions in biofuel discourses are explored through the lens of Maarten Hajer’s “argumentative” discourse analysis. Based on the existence of a “partnership for sustainable bioenergy” between the EU, Brazil and Mozambique, the study takes these three locations as case studies. The analysis reveals that various discursive strategies, including a particular problem construction and the use of two main story-lines, have played an important role in ensuring the permanence of the global approach to biofuels. Moreover, while the discourse of critics against biofuels demonstrates that there is room for contestation, the analysis finds that the opponents’ discourse largely fails to target the most salient justification for biofuels. A more effective strategy for critics would therefore be to also question the problem constructions underpinning this main justification in the global discourse.

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Six of 7 FXYD proteins have been shown to be tissue-specific modulators of Na,K-ATPase. In this study, we have identified two splice variants of human FXYD3, or Mat-8, in CaCo-2 cells. Short human FXYD3 has 72% sequence identity with mouse FXYD3, whereas long human FXYD3 is identical to short human FXYD3 but has a 26-amino acid insertion after the transmembrane domain. Short and long human FXYD3 RNAs and proteins are differentially expressed during differentiation of CaCo-2 cells. Long human FXYD3 is mainly expressed in nondifferentiated cells and short human FXYD3 in differentiated cells and both FXYD3 variants can be co-immunoprecipitated with a Na,K-ATPase antibody. In contrast to mouse FXYD3, which has two transmembrane domains for lack of cleavage of the signal peptide, human FXYD3 has a cleavable signal peptide and adopts a type I topology. After co-expression in Xenopus oocytes, both human FXYD3 variants associate stably only with Na,K-ATPase isozymes but not with H,K-ATPase or Ca-ATPase. Similar to mouse FXYD3, short human FXYD3 decreases the apparent K(+) and Na(+) affinity of Na,K-ATPase over a large range of membrane potentials. On the other hand, long human FXYD3 decreases the apparent K(+) affinity only at slightly negative and positive membrane potentials and increases the apparent Na(+) affinity of Na,K-ATPase. Finally, both short and long human FXYD3 induce a hyperpolarization activated current, similar to that induced by mouse FXYD3. Thus, we have characterized two human FXYD3 isoforms that are differentially expressed in differentiated and non-differentiated cells and show different functional properties.

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The objective in this Master's Thesis was to determine and verify quality criteria for veneer in plywood manufacturing. In plywood manufacturing the veneer quality has a decisive part how well it can be produced to a final product. Modern equipment run at high speed and capacity. These machines require a good quality veneer to be able to maintain them. The quality criteria determination was done after the dominant veneer properties were determined. This research focuses to the birch veneer quality determination. The machines involved in the veneer manufacturing are introduced in the materials and methods section. The different veneer properties are determined and the measuring devices to measure these properties are examined. There are many parts in veneer manufacturing and these have different requirements to the veneer quality. To determine and verify these properties for every machine was the most demanding part of this Master's Thesis. During the research some new ideas and ways to measure veneer properties were also tested. Veneer properties and quality was followed in a factory environment and in a test runs at the Raute. Different machines were followed carefully in the production environment while for example test pieces were taken from veneers that broke on the line. Sample pieces were tested on site or delivered to Nastola for more extensive testing. Based on the tests and research the criteria for veneer to every machine involved in the veneer production were created. These veneer quality tolerances are recommendations to ensure that the machine operation will not be affected by the veneer quality.

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In multifragmentation of hot nuclear matter, properties of fragments embedded in a soup of nucleonic gas and other fragments should be modified as compared with isolated nuclei. Such modifications are studied within a simple model where only nucleons and one kind of heavy nuclei are considered. The interaction between different species is described with a momentum-dependent two-body potential whose parameters are fitted to reproduce properties of cold isolated nuclei. The internal energy of heavy fragments is parametrized according to a liquid-drop model with density- and temperature-dependent parameters. Calculations are carried out for several subnuclear densities and moderate temperatures, for isospin-symmetric and asymmetric systems. We find that the fragments get stretched due to interactions with the medium and their binding energies decrease with increasing temperature and density of nuclear matter.

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Rapid manufacturing is an advanced manufacturing technology based on layer-by-layer manufacturing to produce a part. This paper presents experimental work carried out to investigate the effects of scan speed, layer thickness, and building direction on the following part features: dimensional error, surface roughness, and mechanical properties for DMLS with DS H20 powder and SLM with CL 20 powder (1.4404/AISI 316L). Findings were evaluated using ANOVA analysis. According to the experimental results, build direction has a significant effect on part quality, in terms of dimensional error and surface roughness. For the SLM process, the build direction has no influence on mechanical properties. Results of this research support industry estimating part quality and mechanical properties before the production of parts with additive manufacturing, using iron-based powders

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The detailed in-vivo characterization of subcortical brain structures is essential not only to understand the basic organizational principles of the healthy brain but also for the study of the involvement of the basal ganglia in brain disorders. The particular tissue properties of basal ganglia - most importantly their high iron content, strongly affect the contrast of magnetic resonance imaging (MRI) images, hampering the accurate automated assessment of these regions. This technical challenge explains the substantial controversy in the literature about the magnitude, directionality and neurobiological interpretation of basal ganglia structural changes estimated from MRI and computational anatomy techniques. My scientific project addresses the pertinent need for accurate automated delineation of basal ganglia using two complementary strategies: ? Empirical testing of the utility of novel imaging protocols to provide superior contrast in the basal ganglia and to quantify brain tissue properties; ? Improvement of the algorithms for the reliable automated detection of basal ganglia and thalamus Previous research demonstrated that MRI protocols based on magnetization transfer (MT) saturation maps provide optimal grey-white matter contrast in subcortical structures compared with the widely used Tl-weighted (Tlw) images (Helms et al., 2009). Under the assumption of a direct impact of brain tissue properties on MR contrast my first study addressed the question of the mechanisms underlying the regional specificities effect of the basal ganglia. I used established whole-brain voxel-based methods to test for grey matter volume differences between MT and Tlw imaging protocols with an emphasis on subcortical structures. I applied a regression model to explain the observed grey matter differences from the regionally specific impact of brain tissue properties on the MR contrast. The results of my first project prompted further methodological developments to create adequate priors for the basal ganglia and thalamus allowing optimal automated delineation of these structures in a probabilistic tissue classification framework. I established a standardized workflow for manual labelling of the basal ganglia, thalamus and cerebellar dentate to create new tissue probability maps from quantitative MR maps featuring optimal grey-white matter contrast in subcortical areas. The validation step of the new tissue priors included a comparison of the classification performance with the existing probability maps. In my third project I continued investigating the factors impacting automated brain tissue classification that result in interpretational shortcomings when using Tlw MRI data in the framework of computational anatomy. While the intensity in Tlw images is predominantly