675 research outputs found

    Fabrication and test of a space power boiler feed electromagnetic pump. Part 1: Design and manufacture of pump

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    A three-phase helical induction electromagnetic (EM) pump has been designed and built. This pump was designed for use as the boiler-feed pump of a potassium Rankine-cycle space electric power system. The pump is constructed of high temperature materials including a T-111 duct, Hiperco 27 magnetic material, nickel clad silver conductor wire, and a completely inorganic insulation system. The pump is designed to deliver 3.25 lb/sec potassium at 1000 F with a developed head of 240 psi while being cooled by 800 F NaK. At these conditions, the overall pump efficiency is expected to be 18%

    Impact of Variable Ordering Cost and Promotional Effort Cost in Deteriorated Economic Order Quantity (EOQ) Model

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    The instantaneous economic order quantity (EOQ) profit optimization model for deteriorating items is introduced for analyzing the impact of variable ordering cost and promotional effort cost for leveraging profit margins in finite planning horizons. The objective of this model is to maximize the net profit so as to determine the order quantity and promotional effort factor. For any given number of replenishment cycles the existence of a unique optimal replenishment schedule are proved and further the concavity of the net profit function of the inventory system in the number of replenishments is established. The numerical analysis shows that an appropriate policy can benefit the retailer, especially for deteriorating items. Finally, sensitivity analyses with respect to the major parameters are also studied to draw managerial decisions in production systems

    Mobilising the global significance of multidisciplinary discourses of performativity: lessons from an Australian major league baseballer in the United States and Australian circus performers

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    The discursive construction and expression of multiple forms of identities (self and other; individual, group and community; local, national and international) continue to exercise scholars across a wide range of disciplines, who in turn sometimes seek to exorcise less constructive and enabling representations of certain kinds of marginalised identities. This multi-valenced character of identity discourses is illustrated starkly in the very different status and forms of capital of two occupationally mobile communities with whom this paper is concerned. One group is the highly successful internationally mobile major league baseball players – specifically in this case an Australian player who spent many years travelling the baseball circuits in the United States. The other group is the circuses who travel from place to place in Australia providing public entertainment based on equally specialised skill sets. The paper presents a critically engaged and theoretically informed discourse analysis of empirical data collected with the two groups. The analysis is framed by selected aspects of Judith Butler’s notion of performativity, augmented with more recent theorisation in the field and taking note of the critiques of the concept. The analysis interrogates the discourses of mobility and performativity across the three disciplines of sports biography, life course studies and the sociology of education, in the process distilling areas of potential convergence while acknowledging the appropriate aspects of disciplinary specificity. The analysis is clustered around the emergent organising themes of constructions of home, selfhood and otherness, and multiple identities created and communicated through repeated performances of evolving skills. The paper concludes by examining possible implications of this analysis for contemporary debates about global discourses related to in/equality, discrimination and marginalisation, with particular reference to current and possible future developments in the European polity and society

    Autoradiographic Study of the Turnover of Chromatin-Associated Phospholipids in Vicia Faba L.

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    SUMMARYAutoradiographic data from labelling studies on the incorporation of [14C] ethanolamine into nuclear phospholipids of meristem cells from roots of Vicia faba indicated the presence of a continuous labelling pattern for the nuclear membrane throughout the cell cycle. In contrast, a periodic labelling pattern was observed in chromatin of interphase nuclei which closely paralleled the synthesis pattern for DNA. This corroborated biochemical data from previously published studies of hepatocyte nuclear membranes and chromatin

    The effect of cereal type and enzyme supplementation on carcass characteristics, volatile fatty acids and intestinal microflora and boar taint in entire male pigs

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    A 2 × 2 factorial experiment was conducted to investigate the effects of cereal type (barley v. oat) and exogenous enzyme supplementation (with or without) on intestinal fermentation, and on indole and skatole levels in the intestinal content and the adipose tissue in finisher boars. The experimental treatments were as follows: (i) barley-based diet, (ii) barley-based diet with enzyme supplement, (iii) oat-based diet and (iv) oat-based diet with enzyme supplement. The enzyme supplement contained endo-1,3(4)-β-glucanase (EC 3.2.1.6) and endo-1,4-β-xylanase (EC 3.2.1.8). The animals were fed ad libitum for 45 days from 76.0 to 113.6 kg live weight. Feeding barley-based diets led to higher (P 0.05) between the experimental treatments. Pigs offered the barley-based diets had lower (P < 0.001) indole concentrations in the adipose tissue compared with those fed the oat-based diet. In conclusion, barley-based diets were more efficient than oat-based diets in limiting concentrations of indole in the adipose tissu

    Ion energy distribution measurements in rf and pulsed dc plasma discharges

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    A commercial retarding field analyzer is used to measure the time-averaged ion energy distributions of impacting ions at the powered electrode in a 13.56 MHz driven, capacitively coupled, parallel plate discharge operated at low pressure. The study is carried out in argon discharges at 10 mTorr where the sheaths are assumed to be collisionless. The analyzer is mounted flush with the powered electrode surface where the impacting ion and electron energy distributions are measured for a range of discharge powers. A circuit model of the discharge, in combination with analytical solutions for the ion energy distribution in radio-frequency sheaths, is used to calculate other important plasma parameters from the measured energy distributions. Radio-frequency compensated Langmuir probe measurements provide a comparison with the retarding field analyzer data. The time-resolved capability of the retarding field analyzer is also demonstrated in a separate pulsed dc magnetron reactor. The analyzer is mounted on the floating substrate holder and ion energy distributions of the impinging ions on a growing film, with 100 ns time resolution, are measured through a pulse period of applied magnetron power, which are crucial for the control of the microstructure and properties of the deposited films

    Bacillus species at the Canberra Airport: A comparison of real-time polymerase chain reaction and massively parallel sequencing for identification

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    © 2018 Elsevier B.V. Anthrax, caused by the Gram-positive, spore forming bacterium Bacillus anthracis, is a disease with naturally occurring outbreaks in many parts of the world, primarily in domestic and wild herbivores. Due to the movement of people and stock, B. anthracis could, however, be at transportation hubs including airports. The continuous threat to national and international security from a biological agent release, or hoax attack, is a very real concern. Sensitive, robust and rapid (hours-day) methods to identify biological agents, including B. anthracis, and distinguish pathogenic from non-pathogenic species, is an essential cornerstone to national security. The aim of this project was to determine the presence of Bacillus species at the Canberra Airport using two massively parallel sequencing (MPS) approaches and compare with previous results using real-time polymerase chain reaction (qPCR). Samples were collected daily for seven days each month from August 2011–July 2012 targeting movement of people, luggage and freight into and out of the Canberra Airport. Extracted DNA was analysed using qPCR specific for B. anthracis. A subset of samples was analysed using two MPS approaches. Approach one, using the Ion PGM™ (Thermo Fisher Scientific; TFS) and an in-house assay, targeted the two B. anthracis virulence plasmids (cya and capB genes) and a single conserved region of the 16S rRNA gene. Approach two, using the Ion S5™ (TFS) and the commercial Ion 16S™ Metagenomics Kit (TFS), targeted multiple regions within the bacterial 16S rRNA gene. Overall there was consistency between the two MPS approaches and between MPS and qPCR, however, MPS was more sensitive, particularly for plasmid detection. Whilst the broad-range 16S genomic target(s) used in both MPS approaches in this study was able to generate a metagenomic fingerprint of the bacterial community at the Canberra Airport, it could not resolve Bacillus species beyond the level of the Bacillus cereus group. The inclusion of B. anthracis virulence plasmid targets in the in-house assay did allow for the potential presumptive identifications of pathogenic species. No plasmid targets were in the Ion 16S™ Metagenomics Kit. This study shows the choice of target(s) is key in MPS assay development and should be carefully considered to ensure the assay is fit for purpose, whether as an initial screening (presumptive) or a more specific (but not entirely confirmatory) test. Identification approaches may also benefit from a combination of MPS and qPCR as each has benefits and limitations

    Structure-activity relationships of furanones, dihydropyrrolones and thiophenones as potential quorum sensing inhibitors

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    Since their initial isolation from the marine alga Delisea pulchra, bromofuranones have been investigated as potential inhibitors of quorum sensing (QS) in various bacterial strains. QS is an important mechanism by which bacteria co-ordinate their molecular response to the environment. QS is intrinsically linked to bacterial antibiotic resistance. Inspired by nature, chemists have developed a wide variety of synthetic analogs in an effort to elucidate the structure-activity relationships of these compounds, and to ultimately develop novel antimicrobial agents. In this work, we describe advances in this field while paying particular attention to apparent structure-activity relationships. This review is organized according to the main ring systems under investigation, namely furanones, dihydropyrrolones and thiophenones
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