2,012 research outputs found

    Ionomer-Membrane Water Processing Apparatus

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    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion.RTM., over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water

    Fine-Structure Map of the Histidine Transport Genes in \u3cem\u3eSalmonella typhimurium\u3c/em\u3e

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    Afine-structure genetic map of the histidine transport region of the Salmonella typhimurium chromosome was constructed. Twenty-five deletion mutants were isolated and used for dividing the hisJ and hisP genes into 8 and 13 regions respectively. A total of 308 mutations, spontaneous and mutagen induced, have been placed in these regions by deletion mapping. The histidine transport operon is presumed to be constituted of genes dhuA, hisJ, and hisP, and the regulation of the hosP and hisJ genes by dhuA is discussed. The orientation of this operon relative to purF has been established by three-point crosses as being: purF duhA hisJ hisP

    CSCL: Structuring the Past, Present and Future Through Virtual Portfolios

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    Web-based processes of learning and collaboration produce an enlarged structural opportunity at many levels. Careful structuring of the virtual space supports and adds quality to both collaborative learning between students, and to instruction. Such enhancement in quality may take place through use of individual and collaborative spaces for learning activities, overview of process and content, increased clarity of learning expectations, and facilitation of collaborative and individual processes of reflection and self-reflection. This chapter investigates the structuring potential of a virtual version of portfolios for supporting these aspects. It discusses the conceptual and structural complexity associated with design and use of virtual portfolios from the perspective of, both learners and instructors, and on the basis of the design and use of virtual portfolios in a web-based American course on global change

    Investigation into the semantic density and semantic gravity wave profile of teachers when discussing electrophilic aromatic substitution (SEAr)

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    Language in chemistry is highly specialized and, for students, transitions in language complexity from high school to university can be extremely challenging. With an increasingly diverse cohort of students enrolled upon UK chemistry degree programmes, better understanding the linguistic challenges students face is becoming a greater pedagogical priority. Spoken language plays a central role when learning chemistry, and any misunderstandings can lead to misconceptions that can impede students’ success in this demanding subject. This small-scale study sought to compare the complexity of spoken-language explanations of the same chemical process within UK secondary (high school) and university contexts. The study involved seven organic chemistry educators/teachers, four based in a UK University and three in a UK high school, discussing electrophilic aromatic substitution (SEAr) via a lecture or screencast. The participants’ spoken discourse was transcribed and coded according to the concepts of semantic gravity (the degree to which meaning relates to context) and semantic density (the degree to which meaning is condensed within symbols) drawn from Legitimation Code Theory, and then analyzed for semantic waves. When considering semantic gravity, there were some similarities and some differences. In all cases, semantic gravity was weaker, but participants based in a university environment generally tended to exhibit slightly weaker semantic gravity than their school-based counterparts. The school-based participants usually added further explanations to clarify what was meant during an explanation and exhibited semantic waves by unpacking and re-packing a concept, whereas the university-based participants tended to show a flatter semantic profile. Findings showed that across the levels of study investigated, semantic density was stronger: a similar complexity of chemistry-specific vocabulary used by all seven participants, regardless of the audience. Findings have pedagogical implications and suggest that a larger-scale study of semantic waves in oral chemistry discourse could usefully inform specific-purposes language teaching

    Gated Mode Superconducting Nanowire Single Photon Detectors

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    Single Photon Detectors (SPD) are fundamental to quantum optics and quantum information. Superconducting Nanowire SPDs (SNSPD) [1] provide high performance in terms of quantum efficiency (QE), dark count rate (DCR) and timing jitter [2], but have limited maximum count rate (MCR) when operated as a free-running mode (FM) detector [3, 4]. However, high count rates are needed for many applications like quantum computing [5] and communication [6], and laser ranging [7]. Here we report the first operation of SNSPDs in a gated mode (GM) that exploits a single photon triggered latching phenomenon to detect photons. We demonstrate operation of a large active area single element GM-SNSPD at 625MHz, one order of magnitude faster than its FM counterpart. Contrary to FM-SNSPDs, the MCR in GM can be pushed to GHz range without a compromise on the active area or QE, while reducing the DCR

    Mii and MiiBump: Supporting pregnant women to continue or commence an active lifestyle

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    The purpose of this study was to investigate how women perceive exercising during pregnancy and whether existing technologies could be used to support active behaviours. Information for pregnant women who wish to continue or start exercising is limited and not readily offered. With the ever growing capability and accessibility to technologies research is warranted to investigate whether it could be used to help support exercising during pregnancy. An interpretative phenomenological approach was used to conduct in-depth interviews with five women, via purposive sampling. The data revealed that the participants perceived a number of barriers to active behaviours, such as the lack of a pregnant buddy with which to exercise. A lack of provided information was evident with the women claiming to have sought appropriate information themselves. Findings highlighted the potential for existing technologies to be utilised in order to support and enhance exercise behaviours during pregnancy
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