337 research outputs found

    A conceptual framework for the evaluation of fuel-cell energy systems in the UK built environment.

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    Energy-efficient buildings can reduce human impact on the environment. Energy efficiency is not only concerned with generating more energy using fewer resources, nor reducing energy usage, but also it is about harnessing natural resources, such as wind and sun, to produce energy. The UK government is thus promoting the adoption of renewable energy in buildings. The Fuel-Cell Energy Systems (FCES), which utilizes hydrogen from renewable sources (green hydrogen), is a prominent technology yet with little application in the UK built environment. FCESs can help in addressing the problem of intermittent supplies of renewable energy by allowing for energy storage, which could act as a buffer to meet the variability in user-demand thereby maintaining energy security. Thus, the aim of this article is to explore the application of FCES in the UK built environment by drawing on the scant literature as well as discussion with industry experts. With the recent implementation of FCESs in Scotland, the development of guidelines for evaluation of the FCES is timely. A conceptual framework for the evaluation of FCES is thus outlined in this article, which could be piloted in Scotland (and possibly elsewhere). It is argued that such framework provides a holistic and structured approach for establishing the efficacy of FCES, which is crucial for informing its wider adoption in the future and in particular when it comes to the Return-on-Investment, especially from the perspective of funders and the local community

    A review on fretting fatigie crack initiation criteria

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    Video assisted minimally invasive mitral valve replacement in rheumatic valve disease.

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    Objective: Assessment early outcome of video assisted minimally invasive mitral valve replacement, in rheumatic valve disease. Also, to evaluate early postoperative quality of life by SF 36 questionnaire. Methods: This is a prospective single center study which was conducted on 20 rheumatic heart patients, in Egypt; during the period from October 2015 to June 2018. The main pathological lesion was sever mitral regurgitation (MR), mitral stenosis (MS) or both. Patients underwent video assisted minimally invasive mitral valve replacement, through a right mini thoracotomy. 13 patients (65%) were via infra-mammary incision, 4 patients (20%) were via periareolar incision and 3 patients (15%) were via limited right anterolateral mini-thoracotomy. Results: Mean length of surgical incision was (6.60 ± 1.35 cm). Mean duration of operation, cardiopulmonary bypass, and cross clamp times were (4.32 ± 1.08 hr.), (2.85 ± 0.75 hr.) and (1.78 ± 0.47 hr.) respectively. ICU stay was 2.35 ± 1.14 days and Hospital stay was 6.45 ± 1.43 days. The mean amount of blood loss was 398.50 ± 245.79 ml with two patients of bleeding requiring re-opening. At discharge, all patients had normal mitral prosthetic valve function with no or trivial regurgitation, as shown by echocardiographic studies. The postoperative quality of life revealed faster recovery of usual activities. Conclusions: Video assisted minimally invasive mitral valve surgery in the surgically challenging rheumatic valve disease has less surgical trauma, blood loss and pain, which translates into short hospital stay, rapid return to normal activities, less use of resources

    The ultra-high lime with aluminum process for removing chloride from recirculating cooling water

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    Chloride is a deleterious ionic species in cooling water systems because it is important in promoting corrosion. Chloride can be removed from cooling water by precipitation as calcium chloroaluminate using ultra-high lime with aluminum process (UHLA). The research program was conducted to study equilibrium characteristics and kinetics of chloride removal by UHLA process, study interactions between chloride and sulfate or silica, and develop a model for multicomponent removal by UHLA. Kinetics of chloride removal with UHLA was investigated. Chloride removal was found to be fast and therefore, removal kinetics should not be a limitation to applying the UHLA process. Equilibrium characteristics of chloride removal with UHLA were characterized. Good chloride removal was obtained at reasonable ranges of lime and aluminum doses. However, the stoichiometry of chloride removal with UHLA deviated from the theoretical stoichiometry of calcium chloroaluminate precipitation. Equilibrium modeling of experimental data and XRD analysis of precipitated solids indicated that this deviation was due to the formation of other solid phases such as tricalcium hydroxyaluminate and tetracalcium hydroxyaluminate. Effect of pH on chloride removal was characterized. Optimum pH for maximum chloride removal was pH 12 ± 0.2. Results of equilibrium experiments at different temperatures indicated that final chloride concentrations slightly increased when water temperature increased at temperatures below 40oC. However, at temperatures above 40oC, chloride concentration substantially increased with increasing water temperature. An equilibrium model was developed to describe chemical behavior of chloride removal from recycled cooling water using UHLA. Formation of a solid solution of calcium chloroaluminate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate was found to be the best mechanism to describe the chemical behavior of chloride removal with UHLA. Results of experiments that studied interactions between chloride and sulfate indicated that sulfate is preferentially removed over chloride. Final chloride concentration increased with increasing initial sulfate concentration. Silica was found to have only a small effect on chloride removal. The equilibrium model was modified in order to include sulfate and silica reactions along with chloride in UHLA process and it was able to accurately predict the chemical behavior of simultaneous removal of chloride, sulfate, and silica with UHLA

    Effect of Body Weight on Pattern of Coronary Lesions in Patients Undergoing Coronary Angiography at Sohag University Hospital

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    Background: Obesity is related to multiple risk factors of cardiovascular disease (CVD) including hypertension, diabetes mellitus (DM), metabolic syndrome, and dyslipidemia, while also likely being an independent risk factor for CVD. Through multiple pathways including increased angiotensin, circulating blood volume, and total peripheral resistance, excess weight increases hypertension (HTN) risk.Objective: This study aimed to reveal the relationship between body weight and the severity of coronary artery disease (CAD) in patients referred for coronary angiography at Sohag University Hospital.Patients and methods: This was a cross-sectional hospital-based study performed on 200 patients, at Sohag University Hospital. Mean age was 56.94 ± 10.30 years. Among them, there were 175 patients (87.5%) who were overweight or obese with higher prevalence of HTN, hyperlipidemia, and diabetes. Normal weight patients were 25 (12.5%) with lower prevalence of HTN, hyperlipidemia, and diabetes.Results: According to BMI in our study, 175 patients (87.5 %) were overweight or obese, 162 patients (92.57%) of the overweight had significant coronary artery disease. 162 patients (81%) had significant coronary angiography findings (> 70% stenosis in any of the coronary arteries). They were classified to 63 patients (31.5%) had single vessel diseased, 53 patients (26.5%) had two vessels diseased, and 46 patients (23%) had three vessels diseased.Conclusion: Obesity, diabetes, hypertension, hyperlipidemia, aging and male gender were correlated with severity of CAD. Thus, reduction of weight, stoppage of smoking and control of diabetes, hypertension and hyperlipidemia will improve outcome of coronary artery disease

    Short-term repeated dose biochemical effects of Catha edulis (khat) crude extract administration in rats

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    The leaves of khat (Catha edulis) are reported to have stimulating and pleasurable effects and are chewed habitually by people of East Africa and Arabian Peninsula. Due to various effects of khat the present study was undertaken to evaluate the short-term repeated dose effects of freeze dried khat leaves crude extract administration to male Sprague-Dawley rats. In this study, the effects of catha edulis leaves extract oral administration on plasma concentration of Malonyldialdehyde (MDA), triglycerides, cholesterol, HDL-cholesterol, LDL-cholesterol, uric acid, albumin and testosterone and liver enzymes activities were examined. Four groups of rats were exposed to 0, 500, 1000 and 2000 mg kg 1 body weight/day for 6 consecutive weeks. Our results demonstrated that food consumption and body weights changes were non-significantly different relative to the control. There were no significant effects observed on the levels of plasma MDA, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, uric acid, albumin, liver enzymes or Acid Phosphatase (ACP) in the treatment groups relative to the control. Administration of freeze dried crude catha edulis leaves extract for 6 weeks was found to increase plasma testosterone levels in the two high doses treatment groups (1000 and 2000 mg kg 1 body weight) in more than 2 folds, while it was non-significantly increased in the 500 mg kg 1 body weight treatment group, as compared to control. The data indicated that at the doses and time period tested, catha edulis freeze dried crude extract could be considered as aphrodisiac. Moreover, it did not produce any significant effect on the normal biological markers of liver toxicity or prostatic adverse effects

    THE PREVALENCE OF USING ASPIRIN BY DIABETIC PATIENTS VISITING PRINCE RASHID HOSPITAL

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    Introduction: Diabetes has various health impacts including inflammatory processes. Aspirin is used as anti-inflammatory treatment. Study objectives: to study the prevalence of aspirin use among diabetic patients. Methods and subjects: a retrospective study design was employed to collect data from study participants who attended internal medicine clinics at Rashid Prince Hospital. A total of 447 files of diabetic patients were reviewed. Study variables included age, gender, body mass index, aspirin intake, cardiac diseases, family history of cardiac diseases, and family history of diabetes. Data were analyzed using SPSS version 20. Study findings: the mean age of participants was 55.58+ 10.46 years, 47% of participants were males, and the mean of BMI was 39.18 which implied that participants in general were obese. Aspirin intake was reported by 43% of participants, about 76% of participants had cardiac disease, about 63% of patients had a family history of cardiac disease, and 31% had a family history of diabetes. Aspirin intake was associated significantly with gender (P=0.001) and females were more likely to intake aspirin. No other significant association was observed between aspirin intake and other study variables. Conclusion: the study findings showed that 43% of diabetic patients received aspirin as a treatment, while diabetic patients who had cardiac problems were 76% which implies that the prescription policy of aspirin needs to be revised

    Bayesian network based procedure for regional drought monitoring:The Seasonally Combinative Regional Drought Indicator

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    Drought is a complex natural hazard. It occurs due to a prolonged period of deficient in rainfall amount in a certain region. Unlike other natural hazards, drought hazard has a recurrent occurrence. Therefore, comprehensive drought monitoring is essential for regional climate control and water management authorities. In this paper, we have proposed a new drought indicator: the Seasonally Combinative Regional Drought Indicator (SCRDI). The SCRDI integrates Bayesian networking theory with Standardized Precipitation Temperature Index (SPTI) at varying gauge stations in various month/seasons. Application of SCRDI is based on five gauging stations of Northern Area of Pakistan. We have found that the proposed indicator accounts the effect of climate variation within a specified territory, accurately characterizes drought by capturing seasonal dependencies in geospatial variation scenario, and reduces the large/complex data for future drought monitoring. In summary, the proposed indicator can be used for comprehensive characterization and assessment of drought at a certain region
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