8,890 research outputs found

    Spark plasma sintered carbon electrodes for electrical double layer capacitor applications

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    The spark plasma sintering (SPS) is an emerging process for shaping any type of materials (metals, ceramic, polymers and their composites). The advantage of such a process is to prepare densified ceramic materials in a very short time, while keeping the materials internal porosity. In the present work, we have used the SPS technique to prepare activated carbon-based electrodes for Electrochemical Double Layer Capacitor applications (EDLC). Self-supported 600 and 300µm-thick electrodes were prepared and characterized using of Electrochemical Impedance Spectroscopy and galvanostatic cycling in a non-aqueous 1.5MNEt4BF4 in acetonitrile electrolyte. Electrochemical performance of these sintered electrodes were found to be in the same range – or even slightly better – than the conventional tape-casted activated carbon electrodes. Although organic liquid electrolyte was used to characterize the electrochemical performance of the sintered electrodes, these results demonstrate that the SPS technique could be worth of interest in the ultimate goal of designing solid-state supercapacitors

    The teaser - a multifunctional text-type

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    Die Arbeit untersucht die für den Online-Journalismus typischen, kurzen Ankündungstexte auf den Startseiten ausgewählter, deutschen Online-Zeitungen. Außerdem wird die Ankündigung als mediales Prinzip untersucht, der Teaser in seinen Funktionen beschrieben. Schließlich wird ein Korpus von Teasern unter syntaktischen und stilistischen Aspekten untersucht. Im Ergebnis wird die Textsorte als ausgereift und variantenreich bewertet. Die verschiedenen Textfunktionen wie Orientierung, Information, Lesemotivation werden sprach- stilistisch gezielt unterstützt: lexikalisch z.B durch Eigennamen oder Augenblickskomposita. Syntaktisch konnten interessante Einzelphänomene wie die Steigerung der Satz-Rhythmik durch Ellipsen oder die Ausgliederung von Satzteilen beobachtet werden.This work examines the short typical text-type in Online-Journalism: the teaser. It is found especially on the homepages of online newspapers. The author looks for announcing as a media principle and describes the Teaser in his basic functions. Finally a collection of teasers is evaluated under syntactic and stylistic aspects. In the result the text-type turned out rich in variations. Different text functions like orientation, information, reading motivation are supported straight: e.g. lexical by proper names. Looking on the syntactic structure interesting single phenomena could be observed like the increase of the rhythm of a sentence by ellipses

    Tracing sources and fate of zinc in a mining-impacted river catchment: insights from flow measurements, synoptic sampling, and zinc isotopes

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    This paper reports on the comprehensive monitoring of the Rookhope Burn catchment in the Weardale valley, northern Pennines (Uk), which has been subject to lead, zinc, and fluorspar mining for over two centuries. Zinc is the major contaminant in surface waters, exceeding the Environmental Quality standard value for salmonid fish. synoptic flow monitoring and water sampling have been carried out, including both inflow and instream sampling points along the Rookhope Burn, with the purpose of tracing both point and diffuse sources of Zn throughout the catchment. The Zn load profile suggests an important role for Zn-rich groundwater contributions to the stream bed and has also established the existence of Zn sinks. Evidence from hyporheic zone sampling suggests Zn reaction or surface complexation with Mn oxide surfaces forming on stream bed sediments as a potential mechanism responsible for the observed metal attenuation. Current work is focused on testing the potential of Zn isotopes to fingerprint sources and pathways of Zn in the aquatic system. Preliminary results show significant variation in the stream water Zn isotopic signature from the headwaters to the base of the catchment

    The human journey: From man to men; theme and thematics in the fiction of Bernard Malamud.

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    Said yeats of his time: Things fall apart; the centre cannot hold…. Herbert Gold says of his time, our times: When the center does not hold, we try to make new centers

    In Defense of Institutionalization: A Rape Crisis Center as a Case Study

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    The prevailing wisdom of both the social science literature and of social movement activists postulates that the institutionalization of social movements is a conservatizing tendency. The iron law of oligarchy, Robert Michels\u27 concept, is invoked as the rule of thumb for social movement transformation. From my participant observation study of STOP, an urban rape crisis center, I have drawn different conclusions. In that case study, it appears that institutionalization undermines oligarchy and conservatism, rather than contributing to them. Employing Oberschall\u27s resource mobilization theory of social movement development, I suggest that institutionalization fosters social change efforts at STOP by ensuring organizational stability and resource availability. Second, I propose that institutionalization enables STOP to resist co-optation by providing its participants with material, symbolic, and emotional rewards for organizational loyalty. Finally, I conclude that at STOP institutionalization has inhibited the formation of informal elites, or what Jo Freeman has termed the tyranny of structurelessness

    A talajsavanyodás által előidézett egyéb talajdegradációs folyamatok és az ezekre vonatkozó indikátorok kidolgozása = Analyses of acidity caused soil degradation processes and their early indicators

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    A talajsavanyodás stádiuma a talaj egyik fontos tulajdonsága, mely meghatározza a talaj fizikai, kémiai és biológiai tulajdonságait. Célkitűzésem volt a talajsavanyodás által előidézett talajdegradációs folyamatok vizsgálata és indikátorok kidolgozása. A gyorsan és rutinszerűen elvégezhető kémiai alapparaméterek pontos tájékoztatást adtak a talajok savanyodási mértékéről, azonban talajaink pillanatnyi állapotát tárják elénk. Önmagukban nem nyújtanak elegendő információt a talajdegradáció előrehaladottságáról. A talajok sav/bázis puffertitrálásával számszerű információt kaptunk a különböző talajszintek érzékenységéről. A reológia pontosan és számszerűen fejezte ki a vizsgált talajok szerves és ásványi összetevőinek hatását a szerkezetre. A talajok ásványtani összetételének elemzése bonyolult, hosszadalmas és költséges, ennek ellenére nagyon jó módszerként szolgált a különböző ásványi alkotók mennyiségi elkülönítésére a különböző frakciókban. Ezen paramétereket biológiai paraméterekkel kiegészítve még jobban értelmezhető eredményeket adnak. Az ugróvillások és a földigiliszták egyed- és fajszámának változása jól jelezte a degradáció fokozatait, jó biológiai indikátornak bizonyultak, gyorsan, könnyen és olcsón elvégezhetők. Jól ismételhetők és információt adnak a talajban bekövetkező leromlási folyamatokról, ezáltal időben megkezdhetjük a talajdegradáció elleni beavatkozásokat. | The rate of soil acidification is an important soil property, since it determines the physical, chemical and biological properties of soils. My objectives were to examine the acidity caused soil degradation processes and to develop indicators. The routine laboratory methods gave accurate information about the rate of soil acidification, but only the present status of soil acidity. By the potentiometric titrations of soils we gained quantitative information about the sensitivity of the different soil horizons. By rheology measurements, precise and quantitative information was gained about the effects of organic and minerals fractions on soil structure. However, the mineralogical analyses of soils are very complicated, time consuming and expensive, we found it a very good method to differentiate the mineral composition of soils. These parameters together with the biological parameters can give more understandable results regarding the degradation processes. The change of species number and density of Collembola and earthworms indicated the different levels of soil degradations very well. They are very good biological indicators, since it is relatively quick, easy and cheap use. The examination with these biological indicators can be repeated easily and give information about soil degradation processes in an early stage, thus, we can start acting against the different soil degradation processes

    The relationship between educational pathways and occupational outcomes at the intersection of gender and social origin

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    In this article, we are interested in the differences in the educational pathways and subsequent labour market outcomes by social origin and gender. We apply sequence analyses to model the educational trajectories and conduct regression analyses to determine how the individual's own social status and the salary at labour market entry differs. First, our results show that educational pathways vary by parental status and gender when controlling for reading and mathematics/science skills. Men and pupils with a lower socioeconomic background are overrepresented in vocational education, whereas women and pupils with a more privileged socioeconomic background more often pursue general and academic tracks. Second, these different trajectories lead to unequal occupational status and income. Besides these indirect effects, significant direct effects of parental status and gender on the individual's own occupational status and salary can be found. Together, these findings provide a broad overview of the emergence of inequalities by gender and social origin over the early life course, ranging from differences in skills learned in school to labour market outcomes
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