334 research outputs found

    Ballistic Protection of Military Shelters from Mortar Fragmentation and Blast Effects using a Multi layer Structure

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    In addition to its usage as a top attack ammunition in the battle field against troops, 120 mm mortar bomblethas been recently used in the terror attacks against military shelters and civil constructions. This research studiesthe protection of vehicle and personnel military shelters against mortar fragmentation warhead projectile and it’sdestroying effects. The mortar warhead threat combines both blast load and ballistic fragment penetration effects. Composite structure layers are proposed herein to be integrated with concertina walls to achieve full protection against the mortar projectile destroying effects. The current paper investigates the ability of the proposed layers to stop the mortar’s fragments and to mitigate its blast load. The velocity and the mass distribution of the produced projectile fragments were estimated using Split-X software. Besides, the ability of the proposed protection layers to stop the fragments and mitigate the blast wave was evaluated using AUTODYN hydrocode. A static firing test was then performed to validate the theoretical results and verify the effectiveness of the proposed protection added layers. The current study showed that the proposed composite layers are sufficient to protect the military shelters from the mortar’s destroying ballistic effects

    Domination in Isosceles Triangular Chessboard

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    In this article, we are interested in the domination problem in isosceles triangular chessboard. In our study we take in account one type of piece of rooks, bishops and kings, and two different types of pieces together, kings with rooks, kings with bishops and rooks with bishops. The chessboard in this work is isosceles triangular with square cells. Also in most cases we determine the possible number of different methods of domination (total solution). Keywords: domination, Isosceles triangle chessboard, Kings, Bishops and Rooks

    Towards Non Invasive Diagnosis of Scoliosis Using Semi-supervised Learning Approach

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    Collection : Lecture notes in computer science ; vol. 6112In this paper, a new methodology for the prediction of scoliosis curve types from non invasive acquisitions of the back surface of the trunk is proposed. One hundred and fifty-nine scoliosis patients had their back surface acquired in 3D using an optical digitizer. Each surface is then characterized by 45 local measurements of the back surface rotation. Using a semi-supervised algorithm, the classifier is trained with only 32 labeled and 58 unlabeled data. Tested on 69 new samples, the classifier succeeded in classifying correctly 87.0% of the data. After reducing the number of labeled training samples to 12, the behavior of the resulting classifier tends to be similar to the reference case where the classifier is trained only with the maximum number of available labeled data. Moreover, the addition of unlabeled data guided the classifier towards more generalizable boundaries between the classes. Those results provide a proof of feasibility for using a semi-supervised learning algorithm to train a classifier for the prediction of a scoliosis curve type, when only a few training data are labeled. This constitutes a promising clinical finding since it will allow the diagnosis and the follow-up of scoliotic deformities without exposing the patient to X-ray radiations.CIHR / IRS

    Prediction of scoliosis curve type based on the analysis of trunk surface topography

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    Scoliosis treatment strategy is generally chosen according to the severity and type of the spinal curve. Currently, the curve type is determined from X-rays whose acquisition can be harmful for the patient. We propose in this paper a system that can predict the scoliosis curve type based on the analysis of the surface of the trunk. The latter is acquired and reconstructed in 3D using a non invasive multi-head digitizing system. The deformity is described by the back surface rotation, measured on several cross-sections of the trunk. A classifier composed of three support vector machines was trained and tested using the data of 97 patients with scoliosis. A prediction rate of 72.2% was obtained, showing that the use of the trunk surface for a high-level scoliosis classification is feasible and promising.CIHR / IRS

    Cup versus bottle feeding for hospitalized late preterm infants in Egypt: A quasi-experimental study

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    <p>Abstract</p> <p>Background</p> <p>Although previous studies have demonstrated beneficial breastfeeding outcomes when cup feeding rather than bottle feeding was used for feeding preterm infants, cup feeding has not been implemented in Egypt. The aim of the current study was to examine the effect of using cup feeding as an exclusive method of feeding preterm infants during hospitalization on breastfeeding outcomes after discharge.</p> <p>Methods</p> <p>A quasi-experimental design, with the control group studied first, was used to examine the effect of cup feeding for preterm infants on breastfeeding outcomes after discharge. Sixty preterm infants (mean gestational age was 35.13 weeks and mean birth weight was 2150 grams) were recruited during Neonatal Intensive Care Unit (NICU) stay. Control group infants (n = 30) received only bottle feedings during hospitalization and the experimental group (n = 30) received only cup feedings during hospitalization. Both groups were followed up after discharge for six weeks to evaluate infant's breastfeeding behavior and mother's breastfeeding practices. Data were analyzed using descriptive statistics and repeated measures ANOVA for testing the differences between the cup feeding and bottle feeding groups over six weeks after discharge.</p> <p>Results</p> <p>Cup fed infants demonstrated significantly more mature breastfeeding behaviors when compared to bottle fed infants (p < 0.01) over six weeks, and had a significantly higher proportion of breast feedings one week after discharge (p = 0.03).</p> <p>Conclusion</p> <p>Cup fed infants were more exclusively breast fed one week after discharge, supporting the Baby Friendly Hospital Initiative recommendations for using cup feeding and avoiding bottle feeding when providing supplementation for preterm infants. The current study provides initial evidence for the implementation of cup feeding as a method of supplementation for late preterm infants during hospitalization.</p> <p>Trial Registration</p> <p>Clinical Trial NCT00756587.</p

    Circle grid fractal plate as a turbulent generator for premixed flame: an overview

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    This review paper focuses to ascertain a new approach in turbulence generation on the structure of premixed flames and external combustion using a fractal grid pattern. This review paper discusses the relationship between fractal pattern and turbulence flow. Many researchers have explored the fractal pattern as a new concept of turbulence generators, but researchers rarely study fractal turbulence generators on the structure premixed flame. The turbulent flow field characteristics have been studied tand investigated in a premixed combustion application. In terms of turbulence intensity, most researchers used fractal grid that can be tailored so that they can design the characteristic needed in premixed flame. This approach makes it extremely difficult to determine the exact turbulent burning velocity on the velocity fluctuation of the flow. The decision to carry out additional research on the effect circle grid fractal plate as a turbulent generator for premixed flame should depends on the blockage ratio and fractal pattern of the grid. 1

    Solvation in aqueous binary mixtures: consequences of the hydrophobic character of the ionic liquids and the solvatochromic probes

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    Information on the solvation in mixtures of water, W, and the ionic liquids, ILs, 1-allyl-3-R-imidazolium chlorides; R = methyl, 1-butyl, and 1-hexyl, has been obtained from the responses of the following solvatochromic probes: 2,6-dibromo-4-[(E)-2-(1-R-pyridinium-4-yl)ethenyl] phenolate, R = methyl, MePMBr2; 1-octyl, OcPMBr(2), and the corresponding quinolinium derivative, MeQMBr(2). A model developed for solvation in binary mixtures of W and molecular solvents has been extended to the present mixtures. Our objective is to assess the relevance to solvation of hydrogen-bonding and the hydrophobic character of the IL and the solvatochromic probe. Plots of the medium empirical polarity, E-T(probe) versus its composition revealed non-ideal behavior, attributed to preferential solvation by the IL and, more efficiently, by the IL-W hydrogen-bonded complex. The deviation from linearity increases as a function of increasing number of carbon atoms in the alkyl group of the IL, and is larger than that observed for solvation by W plus molecular solvents (1-propanol and 2-(1-butoxy)ethanol) that are more hydrophobic than the ILs investigated. This enhanced deviation is attributed to the more organized structure of the ILs proper, which persists in their aqueous solutions. MeQMBr(2) is more susceptible to solvent lipophilicity than OcPMBr(2), although the former probe is less lipophilic. This enhanced susceptibility agrees with the important effect of annelation on the contributions of the quinonoid and zwitterionic limiting structures to the ground and excited states of the probe, hence on its response to both medium composition and lipophilicity of the IL.State of Sao Paulo Research Foundation (FAPESP)FAPESP (State of Sao Paulo Research Foundation)CNPq (National Council for Scientific Technological Research)CNPq (National Council for Scientific Technological Research

    Design of immersive virtual reality system to improve communication skills in individuals with autism

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    Individuals with autism spectrum disorder (ASD) regularly experience situations in which they need to give answers but do not know how to respond; for example, questions related to everyday life activities that are asked by strangers. Research geared at utilizing technology to mend social and communication impairments in children with autism is actively underway. Immersive virtual reality (VR) is a relatively recent technology that has the potential of being an effective therapeutic tool for developing various skills in autistic children. This paper presents an interactive scenario-based VR system developed to improve the communications skills of autistic children. The system utilizes speech recognition to provide natural interaction and role-play and turntaking to evaluate and verify the effectiveness of the immersive environment on the social performance of autistic children. In experiments conducted, participants showed more improved performance with a computer augmented virtual environment (CAVE) than with a head mounted display (HMD) or a normal desktop. The results indicate that immersive VR could be more satisfactory and motivational than desktop for children with ASD.Scopu
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