1,046 research outputs found

    Quasiperpendicular high Mach number Shocks

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    Shock waves exist throughout the universe and are fundamental to understanding the nature of collisionless plasmas. Reformation is a process, driven by microphysics, which typically occurs at high Mach number supercritical shocks. While ongoing studies have investigated this process extensively both theoretically and via simulations, their observations remain few and far between. In this letter we present a study of very high Mach number shocks in a parameter space that has been poorly explored and we identify reformation using in situ magnetic field observations from the Cassini spacecraft at 10 AU. This has given us an insight into quasi-perpendicular shocks across two orders of magnitude in Alfven Mach number (MA) which could potentially bridge the gap between modest terrestrial shocks and more exotic astrophysical shocks. For the first time, we show evidence for cyclic reformation controlled by specular ion reflection occurring at the predicted timescale of ~0.3 {\tau}c, where {\tau}c is the ion gyroperiod. In addition, we experimentally reveal the relationship between reformation and MA and focus on the magnetic structure of such shocks to further show that for the same MA, a reforming shock exhibits stronger magnetic field amplification than a shock that is not reforming.Comment: Accepted and Published in Physical Review Letters (2015

    Does Inhalation of Virgin Coconut Oil Accelerate Reversal of Airway Remodelling in an Allergic Model of Asthma?

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    Many studies have been done to evaluate the effect of various natural products in controlling asthma symptoms. Virgin coconut oil (VCO) is known to contain active compounds that have beneficial effects on human health and diseases.The objective of this study was to evaluate the effect of VCO inhalation on airway remodelling in a rabbit model of allergic asthma.The effects of VCO inhalation on infiltration of airway inflammatory cells, airway structures, goblet cell hyperplasia, and cell proliferation following ovalbumin induction were evaluated. Allergic asthma was induced by a combination of ovalbumin and alum injection and/or followed by ovalbumin inhalation.The effect ofVCOinhalationwas then evaluated via the rescue or the preventive route. Percentage of inflammatory cells infiltration, thickness of epithelium and mucosa regions, and the numbers of goblet and proliferative cells were reduced in the rescue group but not in preventive group. Analysis using a gas chromatography-mass spectrometry found that lauric acid and capric acid were among themost abundant fatty acids present in the sample. Significant improvement was observed in rescue route in alleviating the asthma symptoms, which indicates the VCO was able to relieve asthma-related symptoms more than preventing the onset of asthma

    Immersive gaming in the fashion arena: an investigation of brand coolness and its mediating role on brand equity

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    Purpose This study's aim was to investigate the role of the perceived values of gaming on consumers' perceptions of brands as cool as well as the impacts on the consumer–brand equity relationship. The study proposed a framework highlighting the influences of fashion-branded games on brand coolness and building fashion brands' overall equity. As significant factors affecting gamers, gender and gaming have been studied as moderators affecting the overall proposed framework. Design/methodology/approach A quantitative method was used to assess the significance of the relationships within the proposed model. Partial least squares structural equation modeling technique was implemented to assess the framework's relationships with a sample size of 248 active online gamers. Findings The findings indicate that brand equity is positively associated with perceived brand coolness. Furthermore, of the three core online game values, perceived enjoyment was most strongly associated with perceived brand coolness, with other values, such as self-expression and perceived emotional challenge, having a weaker association. The multigroup analysis results further suggest that in the fashion industry, building brand equity through online games is strongly related to perceived brand coolness among female respondents, with the role of perceived brand coolness affecting male respondents to a lesser degree. Originality/value The contribution of this study to the existing literature consists in providing a deeper understanding of the impact of branded games on fashion brands' overall equity. The results provide insights for fashion brand managers into the significant effect of fashion gaming collaborations on consumers' behavioral outcomes

    Characterization of Enzyme Produced from Pseudomonas Putida for BTX (Benzene, Toluene & Xylene) Treatment in Petrochemical Industry Wastewater System

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    One of the big challenges in petrochemical industries is waste management. Currently, huge money was spending on the disposal of the waste. Industries are trying hard to find an alternative method to reduce the cost and improve the effectiveness of current waste management including treatment efficiency. Most of petrochemical wastes are containing benzene, toluene and xylene (BTX) which are very harmful to environment and living organisms. Common method used to separate the BTX from the waste are by using liquid-liquid and stripping process. One of the alternative to treat BTX is biological treatment method that used the natural capability of microorganisms to degrade to less harmful product is been applied. Some of examples are Pseudomonas Putida. (P. putida), Rhizobium, and Agrobacterium. P. putida is selected in this study for the biological treatment of BTX in petrochemical wastewater because it can produce an enzyme that has the capability of breakdown the aromatic hydrocarbon to carbon dioxide (CO2) and water (H2O). The main objective of this study is to produce and extract the enzymes produce, characterised the enzymes. This study also to investigate the effect of different concentration on the treatment as well as the growth of the bacteria. The enzyme is purified using salt precipitation and analysed using SDS_PAGE technique. UV-Vis is used to study the growth of the bacteria in the culture stock by measuring its optical density. The concentration of BTX was varied to determine the effect of the concentration on the percentage removal and the growth of P. putida. Enzymes detected or purified in this study was benzene reductase. Other expected enzymes were not able to be purified or analysed. It was found that in this experimental study, the removal of benzene is at 74% to 80%. The removal of toluene is at 62% to 75%. The removal of xylene is at 23% to 42%. Increasing the concentration of contaminants will reduce the removal capabilities

    The use of intra aortic baloon pump in patients undergoing coronary artery bypass grafting at the Aga Khan University Hospital, Karachi

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    Objective: To review the experience in the use of Intra Aortic Balloon Pump (IABP) in patietits undergoing Coronary Artery Bypass Grafting (CABG) at a tertiary care hospital with a new Open Heart surgery program. Design: Retrospective study. Setting: The Aga Khan University Hospital, Karachi. Patients: Medical records of all patients undergoing CABG between November 1994 and July 1997 were reviewed and those in whom IABP device was used, were included in this study. Results: A total of 15 patients had IABP suppOrt during the study period. Four surgeries were done urgently while two were emergencies. There were three mortalities. Ejection fractions in all hut one patient were impaired. Among the surviving patients, the average pre-IABP Cardiac Index was 2.6 litres/mm/meter2 which registered an average increase of 21.15% after the initiation of the IABP. The Pulmonary Artery Wedge Pressure also showed an average reduction of 29.11% from the pre IABP levels reflecting an increase in the cardiac output with the use of the IABP. Conclusion: This series represents the early experience of a new cardiac surgery center in Pakistan in the use of IABP. Although the numbers in this study are too small to derive any conclusions, the overall morbidity and mortality in this short series are within acceptable limits in the high risk patients include

    Differentiating human from animal isolates of Cryptosporidium parvum.

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    We analyzed 92 Cryptosporidium parvum isolates from humans and animals by a polymerase chain reaction/restriction fragment length polymorphism method based on the thrombospondin-related anonymous protein 2 gene sequence. Used as a molecular marker, this method can differentiate between the two genotypes of C. parvum and elucidate the transmission of infection to humans

    Closed Die Forging Geometrical Parameters Optimization for Al-MMC

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    Abstract: Demand for lighter and stiffer products has been increasing in the last few years especially in automobile manufacturing. The closed die forging process of Metal Matrix Material (MMC) is presented as possible solution, since it produces parts with good mechanical properties and lighter weight. A computational modeling of closed die forging process using finite element method and optimization techniques makes the design optimization faster and more efficient, decreasing the use of conventional trial and error methods. In this study, the application of commercial finite element software (ANSYS) has been used to model cold closed die forging process. The model has been developed using ANSYS Parametric Design Language (APDL) to simulate a single stage axisymmetry closed die forging process for H cross sectional shape. The material used is AlMgSi matrix with 15% SiC particles. Its flow curve and fractural strain are obtained from the literature. ANSYS Optimizer is used to obtain the maximum height in which the material can flow in the rib by changing Design Variables (DV) and State Variables (SV). Normally design variables are geometrical parameters such as, rib height to width ratio, web height to rib height ratio, fillet radii, draft angle and billet radius. State Variables (SV) are some parameters that depend on the design variables such as, the equivalent strain which must be below the fracture strain of the MMC material, and an acceptable contact gap (within the allowable tolerances range). Optimization method called Sub-Problem Approximation Method was used to find out the optimal design set. The technique used in this study can be used for newly developed materials to investigate its forgeability for much complicated shapes in closed die forging process

    THE RELATIONSHIP BETWEEN OBESITY AND DIETARY INTAKE OF OBESE AND PRE-OBESE FEMALE STUDENTS – AJA CAMPUS HAIL UNIVERSITY

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    Globally obesity has reached to epidemic proportions, and the people of the Gulf countries have also affected, especially high income, oilproducing countries. Recent data clearly indicate a high prevalence of adult obesity particularly in women in the Kingdom. This paper aims to identify the relationship between obesity and dietary intake of obese and pre-obese female students in Hail University–KSA. Descriptive analytical approach was used in this paper. BMI was calculated and related to dietary intake using food frequency questionnaire. Results shows prevalence of obesity grades was n(%); 43(43%) obesity grade I, 17(17%) obesity grade II, and 8(8%) were grade III obesity. Thirty one subjects were pre-obese and only one subject was overweight. Basic food groups consumption as stated in frequency per week revealed that: female students consumed more servings (>6 times/ week ) of fruits; vegetables; and dairy products, alternatives, sweets and candies, eggs, legumes, rice macaroni and other starch foods, non-alcoholic beverages. Whereas they consumed less servings (≤Once/ week) of breads, fruit juices, carbonated drinks and potato. The majority of the subjects 65% ate chicken with rice (Kabsa) as staple food, whereas 4% ate other starchy food. High consumption of energy dense foods might be responsible for increased deposition of calories in the form adipose tissue. Conclusion: It is crucial to enumerate awareness programs to modify dietary behavior and eating habits of female students and Hail community with respect to food intake. This will be effective in the treatment of obesity, especially in Saudi Arabia

    Analysis of a Metal Matrix Composites Automotive Component

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    This study presents an implementation of concurrent engineering (CE) and an analytical network process to form a new rating method as part of the manufacturing process and material analysis in the product development environment. The proposed procedure is referred to as a concurrent network (CN). It is planned for CN to carry out simultaneous analysis of all aspects of product elements by using CE strategy. Furthermore, CN enables interdependence and interrelationship analysis between product elements by implementing ANP. In this study, CN is utilized for the manufacturing process and material analysis of a metal matrix composites (MMCs) automotive component which is the brake disc. The results show that by using CN, all the product parameters can be analyzed comprehensively and the importance weights of the product parameters with regard to the MMCs brake disc performance are obtained. It is concluded that in the manufacturing process cluster the primary process parameter has the highest score, while in the material cluster the ranking is dominated by mechanical properties. This means that these sub-conceptual parameters are the most important ones to consider in order to achieve the required performance of the product
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