720 research outputs found

    A privacy preserving approach to energy theft detection in smart grids

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    A major challenge for utilities is energy theft, wherein malicious actors steal energy for financial gain. One such form of theft in the smart grid is the fraudulent amplification of energy generation measurements from DERs, such as photo-voltaics. It is important to detect this form of malicious activity, but in a way that ensures the privacy of customers. Not considering privacy aspects could result in a backlash from customers and a heavily curtailed deployment of services, for example. In this short paper, we present a novel privacy-preserving approach to the detection of manipulated DER generation measurements

    Prediction of the consequences of a CO2 pipeline release on building occupants

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    Carbon Capture and Storage (CCS) is recognised as one of a suite of solutions required to reduce carbon dioxide (CO2) emissions into the atmosphere and prevent catastrophic global climate change. In CCS schemes, CO2 is captured from large scale industrial emitters and transported to geological sites, such as depleted oil or gas fields or saline aquifers, where it is injected into the rock formation for storage. Pipelines are acknowledged as one of the safest, most efficient and cost-effective methods for transporting large volumes of fluid over long distances and therefore most of the proposed schemes for CCS involve onshore and/or offshore high pressure pipelines transporting CO2.In order to manage the risk in the unlikely event of the failure of a CO2 pipeline, it is necessary to define the separation distance between pipelines and habitable dwellings in order to ensure a consistent level of safety. For natural gas pipelines, existing and accepted QRA (Quantitative Risk Assessment) techniques can be implemented to define safety zones based on thermal hazards. However for high pressure CO2 pipelines, for which the hazard is toxic, the consequences of failure need to be considered differently, which will impact on the QRA assessment and the definition of safety distances.The requirement to develop a robust QRA methodology for high pressure CO2 pipelines has been recognised by National Grid as being critical to the implementation of CCS. Consequently, as part of the COOLTRANS (CO2 Liquid pipeline TRANSportation) research programme, failure frequency and consequence models are being developed that are appropriate for high pressure CO2 pipelines. One of the key components in the consequence modelling of a release from a CO2 pipeline is an infiltration model for CO2 into buildings to describe the impact on people inside buildings, and outside seeking shelter, during a release event.This paper describes the development of an infiltration model to predict how the concentration of CO2 within a building will change based on both wind driven and buoyancy driven ventilation of an external CO2 cloud into the building. The model considers the effects of either a constant or changing external concentration of CO2 during a release and allows the density effects of the dense cloud to be taken into account to enable the toxic effects on people within the building to be predicted. The paper then demonstrates how the ventilation model can be coupled to the results of a dispersion analysis from a pipeline release under different environmental conditions to develop the consequence data required for input into the QRA. These effects are illustrated through a case study example

    Methyl orange photo‐degradation by tio2 in a pilot unit under different chemical, physical, and hydraulic conditions

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    The photo‐catalytic degradation of a textile azo‐dye as Methyl Orange was studied in an innovative unit constituted by a channel over which a layer of titanium dioxide (TiO2) catalyst in anatase form was deposited and activated by UVB irradiation. The degradation kinetics were followed after variation of the chemical, physical, and hydraulic/hydrodynamic parameters of the system. For this purpose, the influence of the TiO2 dosage (g/cm3), dye concentration (mg/L), pH of the solution, flow‐rate (L/s), hydraulic load (cm), and irradiation power (W) were evaluated on the degradation rates. It was observed that the maximum dosage of TiO2 was 0.79 g/cm3 while for higher dosage a reduction of homogeneity of the cement conglomerate occurred. The Langmuir– Hinshelwood (LH) kinetic model was followed up to a dye concentration around 1 mg/L. It was observed that with the increase of the flow rate, an increase of the degradation kinetics was obtained, while the further increase of the flow‐rate associated with the modification of the hydraulic load determined a decrease of the kinetic rates. The results also evidenced an increase of the kinetic rates with the increase of the UVB intensity. A final comparison with other dyes such as Methyl Red and Methylene Blue was carried out in consideration of the pH of the solution, which sensibly affected the removal efficiencies

    The introduction and refinement of the assessment of digitally recorded audio presentations

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    This case study critically evaluates benefits and challenges of a form of assessment included in a final year undergraduate Religious Studies Open University module, which combines a written essay task with a digital audio recording of a short oral presentation. Based on the analysis of student and tutor feedback and sample assignments, this study critically examines how teaching and learning practices linked to this novel form of assessment have been iteratively developed in light of the project findings over a period of two years. It concludes that while this form of assessment poses a number of challenges, it can create valuable opportunities for the development of transferable twenty-first-century graduate employability skills as well as deep, effective learning experiences, particularly – though not exclusively – in distance learning settings

    Developing an On-Line Interactive Health Psychology Module.

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    On-line teaching material in health psychology was developed which ensured a range of students could access appropriate material for their course and level of study. This material has been developed around the concept of smaller 'content chunks' which can be combined into whole units of learning (topics), and ultimately, a module. On the basis of the underlying philosophy that the medium is part of the message, we considered interactivity to be a key element in engaging the student with the material. Consequently, the key aim of this development was to stimulate and engage students, promoting better involvement with the academic material, and hence better learning. It was hoped that this was achieved through the development of material including linked programmes and supporting material, small Java Scripts and basic email, forms and HTML additions. This material is outlined as are some of the interactive activities introduced, and the preliminary student and tutor experience described

    Are we training our novices towards quality 2D profiles for 3D models?

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    In the history-based, feature-based, parametric CAD approach, 2D profile sketches are the basis for 3D models. Fully-constraining profiles is mandatory to create robust profiles. At present, neither CAD applications nor Model Quality Testing Tools usually check whether 2D profiles contain redundant constraints. Besides, our experience shows that novices tend to introduce redundant constraints. We hypothesize that 2D profiles over-constrained with redundant relations are more difficult to edit than those that avoid redundancies. In the present work―and as a first step to demonstrate this hypothesis―an experiment was conducted. Students of the subject “Graphics engineering” were taught on the creation of constrained 2D profiles. Then, they were asked two questions. On the one hand, novices had to identify and reason whether a simple given profile was fully-constrained, over-constrained or under-constrained. On the other hand, they had to identify and point out the types of the constraints. The results showed that in spite that novices received a specific training, roughly half of them failed to say if the 2D profile sketch was fully-constrained and which type of constraints it contained. Furthermore, the results of the second question revealed that more than the half of students did not recognize perpendicularity as a geometric constraint. As future work, we will try to demonstrate whether a reinforced training through simple exercises and a quick and effective feedback, will allow novices to improve the identification and removal of redundant 2D constraints when drawing 2D profile sketches (thus helping to produce robust profiles)

    Search for Sub-TeV Gamma Rays Coincident with BATSE Gamma Ray Bursts

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    Project GRAND is a 100m x 100m air shower array of proportional wire chambers (PWCs). There are 64 stations each with eight 1.29 m^2 PWC planes arranged in four orthogonal pairs placed vertically above one another to geometrically measure the angles of charged secondaries. A steel plate above the bottom pair of PWCs differentiates muons (which pass undeflected through the steel) from non-penetrating particles. FLUKA Monte Carlo studies show that a TeV gamma ray striking the atmosphere at normal incidence produces 0.23 muons which reach ground level where their angles and identities are measured. Thus, paradoxically, secondary muons are used as a signature for gamma ray primaries. The data are examined for possible angular and time coincidences with eight gamma ray bursts (GRBs) detected by BATSE. Seven of the GRBs were selected because of their good acceptance by GRAND and high BATSE Fluence. The eighth GRB was added due to its possible coincident detection by Milagrito. For each of the eight candidate GRBs, the number of excess counts during the BATSE T90 time interval and within plus or minus five degrees of BATSE's direction was obtained. The highest statistical significance reported in this paper (2.7 sigma) is for the event that was predicted to be the most likely to be observed (GRB 971110).Comment: To be presented at the XXVIII International Cosmic Ray Conference, Tsukuba, Japa

    A case of panuveitis with hypopyon due to presumed ocular leishmaniasis in a HIV patient.

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    BACKGROUND: Post-kala-azar dermal leishmaniasis is a well-known immunologic cutaneous reaction. There are few case reports of ocular leishmaniasis. It is a sight-threatening condition that needs to be rapidly recognized and treated to avoid permanent visual loss. Ocular leishmaniasis panuveitis can present with severe inflammation in patients with highly active anti-retroviral therapy (HAART)-induced immune reconstitution syndrome. FINDINGS: A case of a 40-year-old man, human immunodeficiency virus (HIV) positive on HAART, with a presumed diagnosis of ocular leishmaniasis, is presented. He had a past history of visceral leishmaniasis and was referred to the uveitis service with rapidly worsening panuveitis and counting fingers vision in both eyes. On empirical anti-leishmania therapy and systemic steroids, the visual acuity of the left eye improved to 6/9 but remained poor in the right eye. Based on the medical history, improvement with therapy and the exclusion of other common infections, a presumed diagnosis of ocular leishmaniasis-related panuveitis was made. CONCLUSIONS: A major immune reaction against lingering parasites may play a key role in the pathogenesis of this sight-threatening and rapidly progressive condition. Both the infection and the immune reaction should be treated
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