754 research outputs found

    Soft Computing for Robust Secure Wireless Reception

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    Soft computing is a collection of different computing methodologies that include neuro computing, fuzzy logic, evolutionary computing, and probabilistic reasoning. These are aimed to exploit the tolerance for imprecision and uncertainty to achieve tractability, robustness, and low solution cost. This paper presents a brief overview of soft computing components, followed by typical realization, via simulation of a wireless receiver employing a hybrid soft computing technique to illustrate its application in a fading signal propagation scenario.Defence Science Journal, 2009, 59(5), pp.517-523, DOI:http://dx.doi.org/10.14429/dsj.59.155

    Laboratory Column flotation studies for reduction of alumina and silica in iron ore slimes of an operating plant

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    A typical iron ore washing plant for treating iron ore fines (<10 mm) consist of sizing of the ore by dry / wet screening, washing, classification by screw classifiers followed by single or multi-stage hydrocycloning of screw classifiers overflow. The underflow of the hydrocyclones forms the concentrate which is suitable for pellets making. Since the cut-point of hydrocyclones is usually at 20 µm or less, relatively lower diameter cyclones in a cluster with parallel feeding are used. This is found to, often, result in choking of the spigots, at times, by extraneous material reporting along with the slurry. It is observed to lead to sub-optimum performance of the cyclones with loss of iron values into cyclone overflow and thereafter into tailings. Analysis of the data of an operating beneficiation plant (Beneficiation plant - 1) of M/s Jindal South West (JSW) Steel Limited, Karnataka, India over a period of one year indicated that weight recovery of the concentrate from two-stage hydrocycloning was 45.9% (with respect to feed to the cyclones) and assaying 63.43% Fe, 4.43% SiO2 and 2.23% Al2O3. Considering the fineness of the slimes (d80: 40.5 µm), generated as screw classifier overflow, flotation is thought to be better alternative vis-à-vis hydrocyclones to recover iron values from it. The present study aims at improving the recovery of the iron values from the screw classifier overflow by adopting reverse cationic column flotation technology. After selecting a suitable collector, process parameters like collector and depressant dosages are optimized by statistically designed experiments on a Denver D12 flotation cell. Later, the effect of important operating parameters of flotation column like air flow-rate, froth depth and wash water on the separation process is studied and optimized. It was established that a typical screw classifier overflow analyzing 60.43% Fe, 6.88% SiO2 and 3.26% Al2O3 could be improved to 63.30% Fe, 4.04% SiO2 and 2.32% Al2O3 with 59.10% weight and 61.70% Fe recovery. This is an improvement of 29% in weight recovery of the concentrate at equivalent metallurgy compared to what is being obtained, by two-stage cycloning

    Extreme ameloblastoma of the mandible with hypoproteinemia: a case report and review of clinicopathological features

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    Ameloblastoma is a tumor of odontogenic epithelium. It has an intermediate malignant potential, thus positioning it in a gray zone between benign and malignant neoplasms. Invasive ameloblastomas of excessive size are rarely confronted. Although these ameloblastomas are benign, they are life threatening. Many have eventuated in death due to airway obstruction, starvation from restriction of feeding, and complications of hypoproteinemia. These tumors cause significant expansion of skin and lips [tissue expanders]. Due to its metabolic demands, a tumor of enormous size will have numerous feeding vessels. Patients with extreme ameloblastomas are usually from rural areas of developing countries who delay the treatment due to fear of surgery. We present a case of extreme ameloblastoma in a 35 year old female which was a consequence of patient negligence. The tumor reached an enormous size over 10 years causing gross facial deformities and posed considerable problems in management

    Alternate charging profiles for the onboard nickel cadmium batteries of the Explorer Platform/Extreme Ultraviolet Explorer

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    The Explorer Platform/Extreme Ultraviolet Explorer (EP/EUVE) spacecraft power is provided by the Modular Power Subsystems (MPS) which contains three 50 ampere-hour Nickel Cadmium (NiCd) batteries. The batteries were fabricated by McDonnell Douglas Electronics Systems Company, with the cells fabricated by Gates Aerospace Batteries (GAB), Gainesville, Florida. Shortly following launch, the battery performance characteristics showed similar signatures as the anomalous performance observed on both the Upper Atmosphere Research Satellite (UARS) and the Compton Gamma Ray Observatory (CGRO). This prompted the development and implementation of alternate charging profiles to optimize the spacecraft battery performance. The Flight Operations Team (FOT), under the direction of Goddard Space Flight Center's (GSFC) EP/EUVE Project and Space Power Applications Branch have monitored and managed battery performance through control of the battery Charge to Discharge (C/D) ratio and implementation of a Solar Array (SA) offset. This paper provides a brief overview of the EP/EUVE mission, the MPS, the FOT's battery management for achieving the alternate charging profile, and the observed spacecraft battery performance

    FAST Spacecraft Battery Design and Performance

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    The Fast Auroral Snapshot (FAST) Explorer spacecraft is to study the physical processes that produce the aurora borealis and aurora australis. It is a unique plasma physics experiment that will take fundamental measurements of the magnetic and electrical fields. This investigation will add significantly to our understanding of the near-earth space environments and its effect. The FAST has a 1 year requirement and 3-year goal for its mission life in low earth orbit. The FAST power power system topology is a Direct Energy Transfer (DET) system based on the SAMPEX design. The FAST flight battery supplies power to the satellite during pre-launch operations, the launch phase, the eclipse periods for all mission phases, and when the load is about 50 watts

    Selective lactase deficiency is common in pediatric patients undergoing upper endoscopy

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    Lactase deficiency can lead to significant symptoms in the pediatric population. To date, few studies have examined the prevalence of enzyme testing-based lactase and other disaccharidase deficiencies (DDs) in pediatric patients undergoing upper endoscopic evaluation. The primary objective of this study was to determine the prevalence of selective lactase and other DDs amongst a large cohort of pediatric patients with and without inflammatory bowel disease (IBD: Crohn’s disease and ulcerative colitis) via a chart review of 739 patients who underwent esophago-gastro-dudenoscopy EGD between April 2010 and August 2016. We identified 560 pediatric patients (ages 1-18 years) who underwent mucosal enzyme testing at the time of their EGD. The overall rate of lactase deficiency (LD) was 39%. LD positively correlated with age (p=0.00017), but there was no significant difference between age matched IBD and non-IBD patients (45% vs. 42% p=0.68). Four patients (0.17%) were found to have selective maltase deficiency. No selective sucrase or palatinase deficiency was identified. Statistically significant differences occurred in lactase deficiency amongst patients of different races. In conclusion, lactase deficiency is a relatively common finding in children undergoing EGD though at no increased rate amongst the IBD patient population. Disaccharidase testing should be considered in pediatric patients undergoing EGD
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