727 research outputs found
Untersuchung innen und auĂen berippter, rohrförmiger, gasgekĂŒhlter Brennelemente
Die vorliegende Arbeit liefert einen Beitrag zur Entwicklung eines rohrförmigen innen und auĂen gekĂŒhlten Brennelementes fĂŒr den Reaktortyp Natururan/Graphit/Gas. An sieben hierfĂŒr geeigneten HĂŒllrohren mit LĂ€ngs-, Quer- und Pfeilrippen wurden mittlere und örtliche WĂ€rmeĂŒbergangszahlen und mittlere Druckverlustbeiwerte gemessen. Die Untersuchungen erfolgten bezĂŒglich KĂŒhlgas, Druck, Temperatur, Massenstrom und Heizleistung unter Reaktorbedingungenim Hochdruckgaskreislauf des Instituts fĂŒr Reaktorbauelemente. Die Aufteilung des KĂŒhlgasmassenstromes in einen turbulenten inneren und Ă€uĂeren Teilstrom wurde theoretisch berechnet und experimentell ĂŒberprĂŒft. Zur Beurteilung der einzelnen Rippenformen wurden in einer Rechnung WĂ€rmeleistung, GeblĂ€seleistung, Uran-, Rippenrohr- und Gastemperatur fĂŒr einen vereinfachten ReaktorkĂŒhlkanal mit Originalabmessungen bestimmt. Die höchste WĂ€rmeleistung wird unter Einhaltung aller Grenzen erreicht, wenn das Uranrohr auĂen und innen mit Pfeilrippenrohren umhĂŒllt wird. Eine nur 11 % geringere WĂ€rmeleistung wird erzielt, wenn das Uranrohr innen mit einem LĂ€ngsrippenrohr umhĂŒllt wird. BerĂŒcksichtigt man, daĂ beim LĂ€ngsrippenrohr die erforderliche GeblĂ€seleistung niedriger und die Herstellungskosten bedeutend geringer sind als beim Pfeilrippenrohr, so erkennt man, daĂ auch LĂ€ngsrippenrohre als InnenhĂŒllrohre durchaus geeignet sind
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Author Correction: Salt concentration and charging velocity determine ion charge storage mechanism in nanoporous supercapacitors
Correction to: Nature Communications; https://doi.org/10.1038/s41467-018-06612-4; published online 08 October 2018
The original version of this Article contained an error in the Acknowledgements, which was incorrectly omitted from the end of the following: âThe research leading to these results has received funding from the European Communityâs Horizon 2020 Framework Programme under grant agreement nÂș 730872.â This has been corrected in both the PDF and HTML versions of the Article
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Tracking the structural arrangement of ions in carbon supercapacitor nanopores using in situ small-angle X-ray scattering
The charge storage mechanism and ion arrangement inside electrically charged carbon nanopores is a very active research field with tremendous importance for advanced electrochemical technologies, such as supercapacitors or capacitive deionization. Going far beyond the state of art, we present for the first time a comprehensive study of tracking ion electrosorption in aqueous electrolytes during charging and discharging of porous carbon electrodes using in situ X-ray scattering. We provide novel and quantitative insights into the local concentration of anions and cations and demonstrate that the global number of ions within the pores does not vary during charging and discharging. In addition, we have unique access to the spatial arrangement of ions inside carbon nanopores by using a simple, yet powerful two-phase model. Applying this model to our data, we show that double-layer formation is accomplished by a unique combination of preferred counter-ion adsorption directly at the pore wall which drains ions from their local surrounding inside carbon nanopores. Effectively, this leads to a situation which globally appears as ion swapping
Fabrication of bismuth nanowires with a silver nanocrystal shadowmask
We fabricated bismuth (Bi) nanowires with low energy electron beam lithography using silver (Ag) nanocrystal shadowmasks and a subsequent chlorine reactive ion etching. Submicron-size metal contacts on the single Bi nanowire were successfully prepared by in situ focused ion beam metal deposition for transport measurements. The temperature dependent resistance measurements on the 50 nm wide Bi nanowires showed that the resistance increased with decreasing temperature, which is characteristic of semiconductors and insulators
Epicatechins Purified from Green Tea (Camellia sinensis) Differentially Suppress Growth of Gender-Dependent Human Cancer Cell Lines
The anticancer potential of catechins derived from green tea is not well understood, in part because catechin-related growth suppression and/or apoptosis appears to vary with the type and stage of malignancy as well as with the type of catechin. This in vitro study examined the biological effects of epicatechin (EC), epigallocatechin (EGC), EC 3-gallate (ECG) and EGC 3-gallate (EGCG) in cell lines from human gender-specific cancers. Cell lines developed from organ-confined (HH870) and metastatic (DU145) prostate cancer, and from moderately (HH450) and poorly differentiated (HH639) epithelial ovarian cancer were grown with or without EC, EGC, ECG or EGCG. When untreated cells reached confluency, viability and doubling time were measured for treated and untreated cells. Whereas EC treatment reduced proliferation of HH639 cells by 50%, EGCG suppressed proliferation of all cell lines by 50%. ECG was even more potent: it inhibited DU145, HH870, HH450 and HH639 cells at concentrations of 24, 27, 29 and 30 ”M, whereas EGCG inhibited DU145, HH870, HH450 and HH639 cells at concentrations 89, 45, 62 and 42 ”M. When compared with EGCG, ECG more effectively suppresses the growth of prostate cancer and epithelial ovarian cancer cell lines derived from tumors of patients with different stages of disease
Everyday self-defence: Hollaback narratives, habitus and resisting street harassment
Street harassment is recognised as an âeverydayâ form of violence against women. Influenced by contemporary sociologies of everyday life, this article examines women responses to street harassment, drawing on over 500 first person narratives submitted to the website of Hollaback London. The narrative structure highlights womenâs actions, which (like street harassment) have generally been considered inconsequential. Quantitative content analysis reveals the extent and variety of strategies employed by women, including speaking back, calling on others for help, physically fighting-back, walking away and an array of âsmallâ, everyday actions and gestures that aim to resist harassment. I argue that these responses comprise everyday self-defence practice. Furthermore, the notion of narrative habitus is employed to argue that Hollaback narratives do not just describe harassment, but that reading narratives can generate dispositions for self-defence. Narrative analysis reveals the way that satire is employed to make space for womenâs successful self-defence. I argue that Hollaback narratives do not just offer storylines or scripts for resisting street harassment but foster a style for doing so. Analysis considers the limits to narratively motivated self-defence. This research demonstrates that, in order to âseeâ womenâs resistance, we need to pay close attention to the everyday as the site of both gendered oppression and moments of liberation
Relationship among research collaboration, number of documents and number of citations. A case study in Spanish computer science production in 2000-2009.
This paper analyzes the relationship among research collaboration, number of documents and number of citations of computer science research activity. It analyzes the number of documents and citations and how they vary by number of authors. They are also analyzed (according to author set cardinality) under different circumstances, that is, when documents are written in different types of collaboration, when documents are published in different document types, when documents are published in different computer science subdisciplines, and, finally, when documents are published by journals with different impact factor quartiles. To investigate the above relationships, this paper analyzes the publications listed in the Web of Science and produced by active Spanish university professors between 2000 and 2009, working in the computer science field. Analyzing all documents, we show that the highest percentage of documents are published by three authors, whereas single-authored documents account for the lowest percentage. By number of citations, there is no positive association between the author cardinality and citation impact. Statistical tests show that documents written by two authors receive more citations per document and year than documents published by more authors. In contrast, results do not show statistically significant differences between documents published by two authors and one author. The research findings suggest that international collaboration results on average in publications with higher citation rates than national and institutional collaborations. We also find differences regarding citation rates between journals and conferences, across different computer science subdisciplines and journal quartiles as expected. Finally, our impression is that the collaborative level (number of authors per document) will increase in the coming years, and documents published by three or four authors will be the trend in computer science literature
Deconstructing the lesbian, gay, bisexual, transgender victim of sex trafficking: Harm, exceptionality and religionâsexuality tensions
Contrary to widespread belief, sex trafficking also targets lesbian, gay, bisexual, transgender (LGBT) communities. Contemporary social and political constructions of victimhood lie at the heart of regulatory policies on sex trafficking. Led by the US Department of State, knowledge about LGBT victims of trafficking constitutes the newest frontier in the expansion of criminalization measures. These measures represent a crucial shift. From a burgeoning range of preemptive measures enacted to protect an amorphous class of âall potential victimsâ, now policies are heavily premised on the risk posed by traffickers to âvictims of special interestâ. These constructed identities, however, are at odds with established structures. Drawing on a range of literatures, the core task of this article is to confront some of the complexities and tensions surrounding constructions of LGBT trafficking victims. Specifically, the article argues that discourses of âexceptional vulnerabilityâ and the polarized notions of âinnocenceâ and âguiltâ inform hierarchies of victimhood. Based on these insights, the article argues for the need to move beyond monolithic understandings of victims, by reframing the politics of harm accordingly
Health and Well-Being of International University Students, and Comparison with Domestic Students, in Tasmania, Australia
International students comprise an increasingly larger proportion of higher education students globally. Empirical evidence about the health and well-being of these students is, however, limited. We sought to examine the health and well-being of international students, primarily from Asian countries, attending the University of Tasmania, Australia, using domestic students as a comparison group. Ethics approval was given to invite (via email) all currently enrolled students to participate in the study by completing a pilot-tested, online survey. The survey was completed by 382 international students (response rate = 8.9%) and 1013 domestic students (9.2%). Independent samples t-tests, analysis of variance (ANOVA) and chi-square tests were used for bivariate comparisons between international and domestic students, and between subgroups of international students. Regression models were used to examine the associations between student status (international vs. domestic) and health outcomes, controlling for demographic and enrolment variables. International students, particularly male students, were found to be at increased risk of several adverse health outcomes while also being less likely to seek help for mental health and related problems. The findings indicate the need for accessible, targeted, culturally-sensitive health promotion and early intervention programs
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