1,553 research outputs found

    Electroless Plating of Ni-B Composite Coating on AZ31 Mg alloy

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    A Niā€“B coating was electroless-deposited directly on H3PO4/HF pickled AZ31. The thickness of the plating layer was estimated through weight gain measurements and was affected by temperature, time and bath composition. The highest thickness was obtained at 6 g/L of NaHB4 at 85oC.Ā  An adherent compact layer of Ni-B was obtained. Electrochemical impedance spectroscopy measurements in 3.5 wt.% sodium chloride aqueous solution suggest that the plating can protect the magnesium alloy substrate from corrosion attack

    Effect of Pickling and Activation Treatments on the Performance of Electroless Plating of Ni-B Coating on AZ31 Mg Alloy

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    Pickling is particularly critical before Ni-B electroless plating to create a uniform and catalytically active surface.Ā  In the present work, pickling treatment of AZ31 Mg alloy was performed in phosphoric acid followed by immersion in 40% HF.Ā  The effect of concentration of both H3PO4 and HF as well as the effect of time were investigated.Ā Ā  The pickled samples were then electroless plated with a Ni-B composite.Ā  The performance of the Ni-B composite coating was investigated under the SEM.Results show that the highest quality coating was obtained upon pickling AZ31 Mg alloy samples in 50% phosphoric acid for 1 min, followed by activation in 40% HF for 15 min. Higher concentration of H3PO4 results in a higher concentration of PO3āˆ’4, leading to a higher tendency to produce insoluble films (mainly Mg3(PO4)2 and AlPO4) on the substrate surface slowing down the rate of Mg alloy oxidization and dissolution.Ā  Activation of pickled AZ31 Mg samples in HF results in the formation of corrosion resistant dense layer of magnesium fluoride. SEM investigation predicted the electroless deposition of an adherent compact layer of Niā€“B composite coating on the H3PO4/HF pickled AZ31 samples. Key Words: AZ31 Mg alloy, pickling, activation, HF, electroless plating DOI: 10.7176/CMR/11-5-04 Publication date:May 31st 201

    Better Heat And Power Integration Of An Existing Gas-oil Plant In Egypt Through Revamping The Design And Organic Rankine Cycle

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    Objective: The current study aims mainly to Maximize Condensate Recovery (NGLs), focusing on a gas processing train of Gas-Oil Separation Plant (GOSP) located in Egypt with a capacity of 4,230 kmole/h. Methods: The research study accounts for the constraint of Reid Vapor Pressure (RVP) specification, which makes the storage in floating roof tanks is of a great risk. The study proposes the installation of the cryogenic train that recovers condensates (C4+). This train comprises of compression unit, expansion unit, three-phase separators and a re-boiled absorber. The problem of RVP will no longer exist because of the re-boiled absorber achieving RVP according to export specifications (RVP below 82.74 kPa). Heat integration is applied over the whole process to minimize the reliability of the external utilities. Further, an Organic Rankine cycle (ORC) is introduced to the existing unit for more heat integration to develop useful work from process waste heat. Furthermore, both environmental emissions of CO2 and economic implications are investigated. Results: Energy integration played a vital role in decreasing the compressing power by about 31%, the cooling load by about 81%, and eliminating the heating load leading to zero CO2 emissions. Conclusion: The new energy-integrated retrofit scenarios exceed the recommended revamping schemes by previous works and base case in all aspects of condensate recovery, energy-saving, environmental concerning and economics

    Effect of metformin on Sirtuin-1 disorders associated with diabetes in male rats

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    Background: Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance, hyperinsulinaemia and hyperglycaemia. Increased glucose production through abnormally elevated hepatic gluconeogenesis is central to the manifestation of hyperglycaemia in T2DM. Metformin corrects hyperglycaemia mainly through inhibition of gluconeogenesis. Sirtuin 1 (SIRT1) has been identified as regulator of gluconeogenic gene expression. The present study aimed to evaluate the effect of metformin on SIRT1 level and activity in liver and pancreas of diabetic rats. Further, the possible role of SIRT1 on metabolic disorders associated with diabetes mellitus, including serum levels of glucose, insulin, triglyceride (TG) and high density lipoprotiens (HDL), will be explored.Methods: Thirty-two male albino rats were divided into control group (GpI), diabetic (DM) group (GpII), (metformin + DM) group (GpIII) administered 120 mg/kg metformin daily for 1 month before induction of diabetes, (DM + metformin) group (GpIV) administered 250 mg/kg metformin daily for 1 month after induction of diabetes. At the end of the study, BMI%, serum levels of glucose, insulin, TG and HDL, HOMA, SIRT1 level and activity in liver and pancreas and pancreatic DNA ladder were assessed.Results: Our results showed significant decrease in serum glucose, insulin and TG levels and HOMA; significant increase in HDL level and SIRT1 level and activity in liver and pancreas beside the marked disappearance of pancreatic apoptosis in GpIII & IV relative to GpII. Regarding BMI%, it showed no significant changes in GpIV relative to GpII. No significant change was recorded between GpIII and GpIV regarding all studied parameters except on serum TG.Conclusion: Lowered SIRT1 in diabetes was improved by the administration of Metformin. Consequently, the pathophysiological disorders associated with T2DM were improved.Keywords: DM, Metformin, SIRT1, Pancreatic apoptosi

    Evaluation of Clinical and Biochemical Traits in Egyptian Barki Sheep with Different Growth Performances.

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    The Barki sheep industry is becoming increasingly important in Egypt because of the high quality of their meat and wool. This sheep breed is also commonly known for its resistance to arid and harsh environmental conditions. Such characteristics can be exploited in solving the problematic situation of inadequate animal protein for human consumption, particularly under climatic changes. However, very few studies have investigated aspects of breeding, nutrition, and susceptibility to infectious or non-infectious diseases in Barki sheep. Herein, we propose to unravel the differences in the clinical and biochemical profiles among Barki sheep of different growth rates. We measured clinical and biochemical parameters in stunted (n = 10; test group) and in good body condition (n = 9; control group) Barki sheep. Animals subjected to this experiment were of the same sex (female), age (12 months old), and housed in the same farm with similar conditions of feeding, management practice, and vaccination and deworming regimens. Regarding clinical examination, stunted/tested sheep showed a significantly higher pulse and respiratory rate compared to sheep with a good body condition/control group. The appetite, body temperature, and digestion processes were the same in both groups. In biochemical investigations, nutritional biomarkers were reduced markedly in stunted sheep compared with the control sheep, including total protein (p = 0.0445), albumin (p = 0.0087), cholesterol (p = 0.0007), and triglycerides (p = 0.0059). In addition, the Barki sheep test group suffered from higher levels of urea and blood urea nitrogen than the control group. Consistently, growth and thyroid hormone levels were lower in stunted sheep than the control sheep, although the differences were not statistically significant (p > 0.05). No significant differences were detected in both groups for serum levels of calcium, phosphorus, magnesium, iron, and zinc (p > 0.05). To detect the reasons for emaciation, certain debilitating infections were tested. All tested sheep showed negative coprological tests for gastrointestinal parasites, and had no obvious seropositivity to brucellosis, toxoplasmosis, neosporosis, or Q fever. This study demonstrates the useful biochemical markers for monitoring growth performance in Egyptian Barki sheep and unravels the usefulness of this breed in nationwide breeding and farming

    Effect of Al2O3 and WO3 Ceramic Additives on the Surface Morphology and Mechanical Properties of Electroless Nickel-Boron Composite Coatings Fabricated on AZ31 Magnesium Alloy

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    In the present study, synthesis and a comparison of properties (structural and mechanical)Ā  ofĀ  Niā€“B and Niā€“Bā€“Al2O3 and Ni-B-WO3 composite coatings have been presentedĀ  toĀ  elucidate the beneļ¬cial roleĀ  of Al2O3 or WO3 addition inĀ  binary Niā€“B coatings. TheĀ  Niā€“Bā€“ Al2O3 and Ni-B-WO3 coatings were synthesized byĀ  adding Al2O3 or NaWO3 powdered particles into theĀ  aboveĀ  mentioned Niā€“BĀ  coating solution.Ā  A signiļ¬cant improvement in mechanical properties has been observed by the addition of Al2O3 or WO3 additions.Ā  This novel composite coating composition will be useful for wear and corrosion applications. DOI: 10.7176/CMR/11-8-05 Publication date:October 31st 201

    Water Conservation and Management Practices at the University of Sharjah to Achieve Sustainability Excellence

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    The University of Sharjah is a leading educational and research institution in the Gulf region. To stimulate the different aspects of sustainability in education and research as well as to ensure the implementation of sustainability concepts throughout the University campus operations, the concept of sustainability circles is implemented. The University being in hot-arid-zone and mostly surrounded by desert terrain relies on unconventional water conservation programs and initiatives such as the use of innovation & technology, reuse and recycling of water, and awareness campaigns. In line with such programs, the use of potable water is limited for hygiene purposes and wastewater generated within the University is reused after treatment to irrigate the vast green spaces through the most efficient irrigation water application systems. Examples of water conservation practices include use of efficient water devices, reuse of treated greywater for toilet flushing at a selected location, water quality monitoring, preservation to conserve water for its intended use, promoting waterless car wash on the campus grounds etc. On-campus water is also conserved through disseminating knowledge and awareness to the University community and beyond through various sustainability related programs and initiatives organized by Sustainability Office for water conservation and environmental protection

    DNA Cytometry and Nuclear Morphometry in Ovarian Benign, Borderline and Malignant Tumors

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    BACKDROUND: Ovarian carcinoma is a leading cause of death in gynecological malignancy. Ovarian surface epithelial serous and mucinous tumours are classified as benign, borderline, and malignant. The identification of borderline tumours most likely to act aggressively remains an important clinical issue.AIM: This work aimed to study DNA ploidy and nuclear area in ovarian serous and mucinous; benign, borderline and malignant tumours.MATERIAL AND METHODS: This study included forty ovarian (23 serous and 17 mucinous) tumours. Paraffin blocks were sectioned; stained with haematoxylin and eosin for histopathologic and morphometric studies and with blue feulgen for DNA analysis.RESULTS: All four serous and six out of nine mucinous benign tumours were diploid. All eight serous and five mucinous malignant tumours were aneuploid. Nine of eleven (81.8%) serous and all three mucinous borderline tumours were aneuploid. There were highly significant differences in mean aneuploid cells percentage between serous benign (1.5%), borderline (45.6%) and malignant (74.5%) (p = 0.0001) and between mucinous benign (13.2%) and both borderline (63.7%) and malignant (68.4%) groups (p = 0.0001).There were significant differences in nuclear area between serous benign (26.191%), borderline (45.619%) and malignant (67.634 %) and a significant positive correlation between mean percentage aneuploid value and mean nuclear area in all serous and mucinous groups.CONCLUSION: We suggest that DNA ploidy and nuclear area combined, may be adjuncts to histopathology; in ovarian serous and mucinous benign, borderline and malignant neoplasms; identifying the aggressive borderline tumours

    The differential effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on seizure frequency in patients with drug-resistant epilepsy ā€“ A Randomized, double-blind, placebo-controlled trial

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    Abstract The omega-3 (n-3) fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known to play an important role in maintenance and modulation of neuronal functions. There is evidence that omega-3 fatty acids may have anticonvulsant effects. The effect of DHA and EPA on seizure rate in patients with DRE was investigated. Methods: A double-blind, randomized, placebo-controlled clinical trial included ninety-nine (n=99) DRE patients, aged 5-16 (n=85) and 17-45 (n=14). After randomization, patients were given two, four or six capsules per day of DHA (417.8 mg DHA and 50.8 mg EPA/capsule, n=33), EPA (385.6 mg EPA and 81.2 mg DHA/capsule, n=33) or placebo (high oleic acid sunflower oil, n=33) for one year. The primary endpoint was the effect of treatment on rate of seizure. Random-effects negative binomial regression models were fitted to model the patientsā€™ total count of seizures per month. The treatment effects on seizure incidence rate ratio was tested after controlling for the covariate effects of gender, age, rate of seizure per week at enrollment, type of seizure and number of AEDs combinations used at enrollment. Results: Fifty-nine patients (n=59) completed the study (59.6%).The average number of seizures per month were 9.7 Ā± 1.2 in the EPA group, 11.7 Ā± 1.5 in the DHA group, and 16.6 Ā± 1.5 in the placebo group. Age, gender and seizure type adjusted seizure incidence rate ratios (IRRs) of the EPA and DHA groups compared with the placebo were 0.61 (CI= 0.42-0.88, p=0.008, 42% reduction) and 0.67 (CI = 0.46-1.0, p= 0.04, 39% reduction), respectively. There was no difference in IRR between the EPA and DHA groups (p=0.56). Both treatment groups had a significantly higher number of seizure-free days compared to placebo (p<0.05). Significance: This study demonstrates that EPA and DHA are effective in reducing seizure frequency in patients with DRE
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