20,506 research outputs found

    Human Trafficking and Terrorism: Utilizing National Security Resources to Prevent Human Trafficking in the Islamic State

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    This is a report of a Master’s thesis done in behalf of the local network in Stockholm, under Fortum Distribution AB. The thesis was to conduct a review of a distribution station named Fs MyrĂ€ngen located in TĂ€by. A model was created for the 11 kV network linked to the secondary side of Fs MyrĂ€ngen. Based on this model and using symmetrical components, theoretical fault currents (short circuit and ground fault) could be calculated. The results of these fault currents are used to investigate and develop new settings for relay protection and ground equipment in the station. The results of the calculated fault currents were also used to investigate unwanted voltages that occurs for grounded parts due to earth faults. The value of these unwanted voltages was then compared to heavy current regulations developed by the Electrical Safety Authority in Sweden. Another element of the work was to create a rehabilitation plan for the structure on the 11 kV side of Fs MyrĂ€ngen, the main goal regarding the rehabilitation plan was to investigate the advantages and disadvantages that exist at a possible transition to numerical protection relays. This was done by making a market overview of the different types of numerical protection relays and compare these with the existing analog protective device in Fs MyrĂ€ngen. The study showed that protective relay settings should be revised according to the recommendations in the report, ground equipment should be replaced with a self-regulating type, transformers should be replaced due to age and capacity limitations. Regarding a switch to numerical protection relays the type REF615 from ABB was recommended, in that case the control board in the station should be replaced to a station computer. Furthermore should current transformers be replaced to recive a desired sensitivity regarding detection of ground faults. The report also showed that Fs MyrĂ€ngen meets the regulations of unwanted voltages over grounded parts in distribution stations due to earth faults.Detta Ă€r en rapport av ett examensarbete utfört i uppdrag av lokalnĂ€t Stockholm under Fortum Distribution AB. Examensarbetet gick ut pĂ„ att göra en översyn av en fördelningsstation vid namn Fs MyrĂ€ngen som Ă€r belĂ€gen i TĂ€by. En modell skapades av 11 kV nĂ€tet kopplat till Fs MyrĂ€ngen, utifrĂ„n denna modell samt med hjĂ€lp av symmetriska komponenter berĂ€knades teoretiska felströmmar bĂ„de för kortslutning och jordslutning. Resultaten av dessa felströmmar anvĂ€ndes för att utreda och ta fram instĂ€llningar pĂ„ relĂ€skydd och nollpunktsutrustning i stationen. Resultaten pĂ„ framrĂ€knade jordfelsströmmar anvĂ€ndes Ă€ven för att utreda vilken spĂ€nningssĂ€ttning som uppstĂ„r vid jordfel, i de nĂ€tstationer som matas av Fs MyrĂ€ngen. SpĂ€nningssĂ€ttningen pĂ„ nĂ€tstationerna jĂ€mfördes sedan med de starkströmsföreskrifter som Ă€r framtagna av elsĂ€kerhetsverket. Ett annat moment i arbetet var att skapa en upprustningsplan för skyddsanordningen pĂ„ 11 kV sidan i Fs MyrĂ€ngen, huvudmĂ„let för den biten var att utreda vilka fördelar och nackdelar som finns vid en eventuell övergĂ„ng till numeriska skydd. Detta gjordes genom att göra en marknadsöversikt över olika typer av numeriska relĂ€skydd, samt jĂ€mföra dessa med den befintliga skyddsanordningen i MyrĂ€ngen som Ă€r av analog typ. Studien visade att relĂ€skyddsinstĂ€llningar bör ses över enligt rekommendationer i rapporten, nollpunktsutrustningen bör bytas ut till sjĂ€lvreglerande typ, transformatorerna bör bytas ut p.g.a. Ă„lder och kapacitetsbegrĂ€nsning. GĂ€llande skyddsanordningen rekommenderas en övergĂ„ng till numeriska skydd av typen REF615, och i samband med detta byta ut den befintliga kontrolltavlan i stationen till en stationsdator. Vidare bör Ă€ven strömtransformatorer för jordfelsskydden bytas ut för att uppnĂ„ önskad kĂ€nslighet gĂ€llande detektering av jordfel. För spĂ€nningssĂ€ttning av nĂ€tstationer vid jordfel, visar resultaten att stationen uppfyller kraven enligt starkströmsföreskrifterna frĂ„n elsĂ€kerhetsverket

    THE BIOLOGICAL AND STRUCTURAL CHARACTERIZATION OF TRANSFERABLE BACTEROIDES R PLASMIDS

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    In this literature review I will briefly describe the general biology of transferable antibiotic resistance in bacteria, the genetic elements involved (plasmids) and several specific plasmid associated phenotypes. This will be followed with a review of the general biology of Bacteroides, the information known concerning its plasmid reservoir and finally a review of the information documenting the emergence of transferable clindamycin resistance in Bacteroides. The latter aspect represents the central focus of research described in this thesis

    Implications of skeletal muscle loss for public health nutrition messages:a brief report

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    Age-related skeletal muscle loss, sarcopenia, cachexia and wider malnutrition (under nutrition) are complex in aetiology with interaction of clinical, social and economic factors. Weight loss and loss of skeletal muscle mass in older people are associated with increased morbidity and mortality with implications for increasing health and social care costs. There is insufficient evidence to identify the ideal treatment options. However, preventing weight loss and loss of skeletal muscle in older age will be keys to reducing morbidity and mortality. This will require all those coming into contact with older people to identify and address weight loss early, including through diet, improving physical activity and increasing social interaction. Public health messages on diet should, in the main, continue to focus on older people achieving current UK dietary recommendations for their age as visually depicted in the eatwell plate together with associated messages regarding dietary supplements where appropriate

    Evaluation of Composite Materials for Use on Launch Complexes

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    Commercially available composite structural shapes were evaluated for use. These composites, fiberglass-reinforced polyester and vinylester resin materials are being used extensively in the fabrication and construction of low maintenance, corrosion resistant structures. The evaluation found that in many applications these composite materials can be successfully used at the space center. These composite materials should not be used where they will be exposed to the hot exhaust plume/cloud of the launch vehicle during the liftoff, and caution should be taken in their use in areas where electrostatic discharge and hypergolic propellant compatibility are primary concerns

    An adaptive, hanging-node, discontinuous isogeometric analysis method for the first-order form of the neutron transport equation with discrete ordinate (SN) angular discretisation

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    In this paper a discontinuous, hanging-node, isogeometric analysis (IGA) method is developed and applied to the first-order form of the neutron transport equation with a discrete ordinate (SN) angular discretisation in two-dimensional space. The complexities involved in upwinding across curved element boundaries that contain hanging-nodes have been addressed to ensure that the scheme remains conservative. A robust algorithm for cycle-breaking has also been introduced in order to develop a unique sweep ordering of the elements for each discrete ordinates direction. The convergence rate of the scheme has been verified using the method of manufactured solutions (MMS) with a smooth solution. Heuristic error indicators have been used to drive an adaptive mesh refinement (AMR) algorithm to take advantage of the hanging-node discretisation. The effectiveness of this method is demonstrated for three test cases. The first is a homogeneous square in a vacuum with varying mean free path and a prescribed extraneous unit source. The second test case is a radiation shielding problem and the third is a 3×3 “supercell” featuring a burnable absorber. In the final test case, comparisons are made to the discontinuous Galerkin finite element method (DGFEM) using both straight-sided and curved quadratic finite elements

    Response of mouse epidermal cells to single doses of heavy-particles

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    The survival of mouse epidermal cells to heavy-particles has been studied In Vivo by the Withers clone technique. Experiments with accelerated helium, lithium and carbon ions were performed. The survival curve for the helium ion irradiations used a modified Bragg curve method with a maximum tissue penetration of 465 microns, and indicated that the dose needed to reduce the original cell number to 1 surviving cell/square centimeters was 1525 rads with a D sub o of 95 rads. The LET at the basal cell layer was 28.6 keV per micron. Preliminary experiments with lithium and carbon used treatment doses of 1250 rads with LET's at the surface of the skin of 56 and 193 keV per micron respectively. Penetration depths in skin were 350 and 530 microns for the carbon and lithium ions whose Bragg curves were unmodified. Results indicate a maximum RBE for skin of about 2 using the skin cloning technique. An attempt has been made to relate the epidermal cell survival curve to mortality of the whole animal for helium ions

    Non-thermal X-ray Emission: An Alternative to Cluster Cooling Flows?

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    We report the results of experiments aimed at reducing the major problem with cooling flow models of rich cluster X-ray sources: the fact that most of the cooled gas or its products have not been found. Here we show that much of the X-ray emission usually attributed to cooling flows can, in fact, be modeled by a power-law component which is indicative of a source(s) other than thermal bremsstrahlung from the intracluster medium. We find that adequate simultaneous fits to ROSAT PSPCB and ASCA GIS/SIS spectra of the central regions of ten clusters are obtained for two-component models that include a thermal plasma component that is attributable to hot intracluster gas and a power-law component that is likely generated by compact sources and/or extended non-thermal emission. For five of the clusters that purportedly have massive cooling flows, the best-fit models have power-law components that contribute ∌\sim 30 % of the total flux (0.14 - 10.0 keV) within the central 3 arcminutes. Because cooling flow mass deposition rates are inferred from X-ray fluxes, our finding opens the possibility of significantly reducing cooling rates.Comment: 11 pages, 3 figures, emulateapj style. Accepted for publication in Ap
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