5,742 research outputs found

    Measurement of single event upsets in the ALICE-TPC front-end electronics

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    The Time Projection Chamber of the ALICE experiment at the CERN Large Hadron Collider features highly integrated on-detector read-out electronics. It is following the general trend of high energy physics experiments by placing the front-end electronics as close to the detector as possible -- only some 10 cm away from its active volume. Being located close to the beams and the interaction region, the electronics is subject to a moderate radiation load, which allowed us to use commercial off-the-shelf components. However, they needed to be selected and qualified carefully for radiation hardness and means had to be taken to protect their functionality against soft errors, i.e. single event upsets. Here we report on the first measurements of LHC induced radiation effects on ALICE front-end electronics and on how they attest to expectations

    CFD-based process optimization of a dissolved air flotation system for drinking water production

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    Dissolved air flotation (DAF) has received more attention recently as a separation technique in both drinking water as well as wastewater treatment. However, the process as well as the preceding flocculation step is complex and not completely understood. Given the multiphase nature of the process, fluid dynamics studies are important to understand and optimize the DAF system in terms of operation and design. The present study is intended towards a comprehensive computational analysis for design optimization of the treatment plant in Kluizen, Belgium. Setting up the modelling framework involving the multiphase flow problem is briefly discussed. 3D numerical simulations on a scaled down model of the DAF design were analysed. The flow features give better confidence, but the flocs escape through the outlet still prevails which is averse to the system performance. In order to improve the performance and ease of maintenance, design modifications have been proposed by using a perforated tube for water extraction and are found to be satisfactory. The discussion is further reinforced through validating the numerical model against the experimental findings for stratified flow conditions

    Hawking radiation of scalar particles from accelerating and rotating black holes

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    Hawking radiation of uncharged and charged scalars from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using the tunneling method we recover the correct Hawking temperature as well

    Equivalent Circuit Modeling of the Dielectric Loaded Microwave Biosensor

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    This article describes the modeling of biological tissues at microwave frequency using equivalent lumped elements. A microwave biosensor based on microstrip ring resonator (MRR), that has been utilized previously for meat quality evaluation is used for this purpose. For the first time, the ring-resonator loaded with the lossy and high permittivity dielectric material, such as; biological tissue, in a partial overlay configuration is analyzed. The equivalent circuit modeling of the structure is then performed to identify the effect of overlay thickness on the resonance frequency. Finally, the relationship of an overlay thickness with the corresponding RC values of the meat equivalent circuit is established. Simulated, calculated and measured results are then compared for validation. Results are well agreed while the observed discrepancy is in acceptable limit

    Isothermal study of Congo Red dye biosorptive removal from water by Solanum tuberosum and Pisum sativum peels in economical way

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    Solanum tuberosum (STP) and Pisum sativum peels (PSP) were used for removal of toxic Congo Red dye using indigenous sources. Potato (Solanum tuberosum) and pea (Pisum sativum) are commonly and abundantly cultivated plants in Asian countries and their peels are easily available. The optimized conditions for Solanum tuberosum peels (STP) and Pisum sativum peels (PSP) were: adsorbent dose; 0.8 and 0.6 g, contact time; 50 and 35 min, pH; 3 and 2, agitation speed; 200 and 125 rpm and temperature; 30 oC for both STP and PSP respectively. Isothermal studies indicated that Langmuir model followed by equilibrium data more than Freundlich model. Negative value of thermodynamic parameter ∆Go shown that Cong Red removal by both adsorbents was spontaneous and exothermic in nature. The adsorption capacity (qmax) for Solanum tuberosum and Pisum sativum peels were found to be 6.9 and 16.4 mg.g-1, respectively. Higher value of qmax for pea peels shown that it is more suitable adsorbent for removal of Congo Red dye than potato peels.               KEY WORDS: Congo red, Solanum tuberosum, Pisum sativum, Biosorption Bull. Chem. Soc. Ethiop. 2018, 32(2), 213-223.DOI: https://dx.doi.org/10.4314/bcse.v32i2.

    Coherent acceleration of material wavepackets in modulated optical fields

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    We study the quantum dynamics of a material wavepacket bouncing off a modulated atomic mirror in the presence of a gravitational field. We find the occurrence of coherent accelerated dynamics for atoms beyond the familiar regime of dynamical localization. The acceleration takes place for certain initial phase space data and within specific windows of modulation strengths. The realization of the proposed acceleration scheme is within the range of present day experimental possibilities

    Natriuretic Peptide Testing in Primary Care

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    The incidence, as well as the morbidity and mortality associated with heart failure (HF) continue to rise despite advances in diagnostics and therapeutics. A recent advance in the diagnostic and therapeutic approach to HF is the use of natriuretic peptide (NP) testing, including both B-type natriuretic peptide (BNP) and its amino terminal cleavage equivalent (NT-proBNP). NPs may be elevated at an early stage among those with symptoms as well among those without. The optimal approach for applying NP testing in general populations is to select the target population and optimal cut off values carefully. Superior diagnostic performance is observed among those with higher baseline risk (such as hypertensives or diabetics). As well, unlike for acute HF, the cut off value for outpatient testing for BNP is 20-40 pg/mL and for NTproBNP it is 100-150 ng/L. In symptomatic primary care patients, both BNP and NT-proBNP serve as excellent tools for excluding HF based on their excellent negative predictive values and their use may be cost effective. Among those with established HF, it is logical to assume that titration of treatment to achieve lower NPs levels may be advantageous. There are several ongoing trials looking at that prospect

    Hydrodynamic Modelling for a Transportation System of Two Unmanned Underwater Vehicles: Semi-Empirical, Numerical and Experimental Analyses

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    Underwater transportation is an essential approach for scientific exploration, maritime construction and military operations. Determining the hydrodynamic coefficients for a complex underwater transportation system comprising multiple vehicles is challenging. Here, the suitability of a quick and less costly semi-empirical approach to obtain the hydrodynamic coefficients for a complex transportation system comprising two Unmanned Underwater Vehicles (UUVs) is investigated, where the interaction effects between UUVs are assumed to be negligible. The drag results were verified by Computational Fluid Dynamics (CFD) analysis at the steady state. The semi-empirical results agree with CFD in heave and sway; however, they were overpredicted in surge due to ignoring the wake effects. Furthermore, experiments were performed for the validation of the time-domain motion simulations with semi-empirical and CFD results. The simulations which were performed with the CFD drags were close to the experiments. The semi-empirical approach could be relied on once a correction parameter is included to account for the interactive effect between multiple UUVs. Overall, this work makes a contribution by deriving a semi-empirical approach for the dynamic and controlling system of dual UUVs, with CFD and experiments applied to ascertain its accuracy and potential improvement
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