478 research outputs found

    Studying the Electron Energy Distribution Function (EEDF) and Electron Transport Coefficients in SF6 – He Gas Mixtures by Solving the Boltzmann Equation

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    The Boltzmann equation has been solved using (EEDF) package for a pure sulfur hexafluoride (SF6) gas and its mixtures with buffer Helium (He) gas to study the electron energy distribution function EEDF and then the corresponding transport coefficients for various ratios of SF6 and the mixtures. The calculations are graphically represented and discussed for the sake of comparison between the various mixtures. It is found that the various SF6 – He content mixtures have a considerable effect on EEDF and the transport coefficients of the mixture

    Scanning Capacitance Spectroscopy on n\u3csup\u3e+\u3c/sup\u3e-p Asymmetrical Junctions in Multicrystalline Si Solar Cells

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    We report on a scanning capacitance spectroscopy (SCS) study on the n+-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in the literature. These distinctive spectra are due to uneven carrier-flow from both the n- and p-sides. Our results contribute significantly to the SCS study on asymmetrical junctions

    The Effect of Basal Diet on Lactate-Producing Bacteria and the Susceptibility of Sheep to Lactic Acidosis

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    The influence of a diet of either pasture or hay on the development of lactic acidosis in sheep was investigated using a grain challenge approach. Twenty-four Merino wethers with a mean live weight of 36.7 (s.e. 3.6) kg were used; 12 were adapted to grass pasture and 12 to hay (lucerne and oaten hay, 60 : 40) for 4 weeks before being given 1 kg of crushed barley via stomach tube. Six sheep in each group were also given virginiamycin (VM; 50 mg/kg barley) with the grain to test the efficacy of this antibiotic in controlling the bacteria responsible for the development of acidosis. Changes in volatile fatty acid (VFA), pH, lactate and bacterial count in the rumen and faecal pH and dry matter (DM) were measured for a 24-h period following administration of the barley. Daily intakes of hay were measured for a 10-day period following grain engorgement. Total ruminal VFA increased (P < 0.01) over time and tended (P = 0.08) to be higher in sheep adapted to hay than in those adapted to pasture (67.5 v. 59.8 mmol/l). The molar proportions of VFA changed (P< 0.01) over time in favour of propionate in both groups. Ruminal pH was higher (P< 0.001) in pasture-adapted sheep, but declined (P< 0.001) in both groups over time following the introduction of barley. This decline in pH was associated with increases in ruminal concentration of VFA in pasture-adapted sheep and VFA and lactate in hay-adapted sheep. The addition of VM resulted in a higher (P < 0.001) proportion of propionate and a trend towards higher (P = 0.24) faecal pH and DM content. Faecal pH and DM content declined (P < 0.001) over time and was lower for the pasture-adapted sheep. The introduction of either barley alone or barley with VM from both hay and pasture diets increased (P < 0.05) the viable counts of total bacteria, Streptococcus bovis and lactic acid bacteria. Bacterial isolates were purified and identified by complete sequencing of the 16S rRNA gene to determine the predominant bacteria during the overfeeding of grain. Isolates from medium selective for S. bovis were all identified as this species when VM was not given. VM had no effect on counts of viable bacteria, but inhibited the growth of S. bovis

    Varicella-zoster virus transverse myelitis in an immunocompetent patient

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    Transverse myelitis is one of the rare neurological complications of Varicella-Zoster Virus (VZV) infection in immuno-competent. We report a 26-year-old immuno-competent gentleman who developed virologically confirmed myelopathy caused by VZV which improved with steroids and acyclovir leaving no residual neurological deficits

    Petroleum system analysis of the Lower Jurassic-Upper Cretaceous source rocks and Miocene reservoirs in the NE of Iraq

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    The Carbonat/evaporit cycles in the North of Iraq for the LOwer Jurassic-Upper Cretaceous time interval were studied to investigate their source rock intervals sa well as residual bitumen and crud oil in the Miocene resevoir

    Barramundi (Lates calcarifer) from Iraq: a new record for the Arabian Gulf, with a highlight on it genetic origins and description of two skeletal deformities

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    The natural distribution of Lates calcarifer (barramundi or Asian sea bass), ranges from western India, around Sri Lanka to the Bay of Bengal, and through the whole of Southeast Asia to Papua New Guinea and northern Australia. It is not known to be native to the Arabian Gulf, although the species has recently been introduced for aquaculture production in Iran. In 2019, 12 adult barramundi were caught from freshwater in the Shatt al-Arab River, its estuary and marine waters bordering Iraq. This is the first wild-capture record of this species for Iraq’s inland waters and the northern Arabian Gulf. The specimens were morphologically described, while genetic structure analyses indicated that the specimens likely originated from Australian and Thailand genetic stocks and thus probably were aquaculture escapees from farmed populations. Among the L. calcarifer collected from the freshwater environment on the Shatt al-Arab River, one specimen exhibited saddleback syndrome, and another showed abnormality in the left operculum. The results are interesting and useful in reminding people to prevent aquaculture escapees. The aim of this study was to morphologically describe the specimens and undertake a genetic analysis to determine the likely provenance of the fish

    Effect of tail docking in Awassi lambs on metabolizable energy requirements and chemical composition of carcasses

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    The effect of tail docking on metabolizable energy requirements and carcass characteristics was studied using 80 weaned entire Awassi male lambs. Docking was performed within 3 days of birth and lambs were weaned at 90 days old. Docked and undocked lambs were randomly allocated to four groups, individually penned and offered different amounts of a pelleted concentrate diet. The pelleted diet was estimated to contain 11.8 MJ of metabolizable energy (ME) and 182 g of crude protein (CP) per kg dry matter (DM). Lambs on the high levels of intake were slaughtered at a target weight of approximately 45 kg. Other lambs were maintained on the diet for 149 days before being slaughtered. The right sides of all carcasses were cut into standardized commercial cuts then dissected into muscle, fat and bone. The soft tissue was pooled and analysed for DM, CP, ash and fat. Prediction of live-weight gain (LWG) and empty body gain for a given ME intake (MEI) was made using the growth and MEI data. MEI was expressed as MJ per kg metabolic body weight (M 0.75) per day. Tail docking had no effect (P> 0.05) on lamb growth from birth to weaning. During the post-weaning growth period, LWG and empty body gain were significantly higher (P 0.05) at high levels of intakes (between 0.74 and 1.1 MJ/kg M 0.75 per day). Hot and cold carcass weights were similar (P > 0.05) for the two groups. Differences in empty body weight and fleece-free empty body weight were significant (P 0.05) on food conversion efficiency (FCE). Carcasses from docked lambs had significantly lower (P 0.05) ash content

    Evaluation of the Corrosion Rate of Different Types of Marine Ship Steel using Potentiostatic Test Method in Arabian Gulf Sea Water

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    The effect of flow velocity and chemical composition of Arab gulf sea water on the corrosion behavior of three different types of steel (DNV/EH40, AB/FH32 and ABS DQ47) used in building of marine ship hull structures investigated by using electrochemical Potentiostatic test method was. The results indicate that the general corrosion rate under flow condition is larger than that obtained under static case. Increasing the velocity of sea water leads to increase the corrosion rates for certain limit and then began to decrease. NV/EH40 steel exhibited a significantly lower values of corrosion rate, ABS DQ47 steel has larger values and AB/FH32 marine steel plates has moderate values
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