Performance test of Parabolic Trough Solar Cooker for indoor cooking

Fuel-wood scarcity is a growing problem that has so far been poorly addressed. Solar cooking is one possible solution but its acceptance has been limited partially due to low performance and convenience of use of most of the solar cookers that currently are available. The objective of this research is to test the performance of a solar cooker based on concentrating collector and increase its temperature and performance. Parabolic trough cooker (PTC) was constructed in a way allowing cooking to be done indoors, which the cooking sections were placed indoor whiles the collector parts out-door with soya bean oil conveying the energy from the absorber to the cooking stove. Ray tracing and standard stagnation tests show a 30 mm diameter copper pipe is the optimum size for the absorber. Maximum temperatures of 1910C at the mid absorber pipe and 1190C at the cooking stove were obtained. The efficiency of the system was found to be 6%.Keywords: Solar cooking, Concentrator, Stagnation test, Ray tracing

Design and Manufacture of 1kW Wind Turbine Blades

To meet sustainable development goals and address concerns on climate change, much of the world's energy demand is expected to be delivered from clean alternative energy sources. Small-scale wind turbines have proven to be applicable for off-grid electrification. The objective of this study is to present the details on the design and manufacture of a 1 kW wind turbine blade for specified conditions. Blade element moment theory is adopted in the design of the geometry of the blade. Accordingly, the aerodynamic analysis on NACA 64A410 airfoil resulted in a blade radius of 1.95m, an overall twist angle of 31°, and a gradually tapering chord length of 0.062m at the root and 0.247m at the tip of the blade. Then, the wind turbine blades are manufactured from fiberglass (mat350g), resin, catalyst, and gelcoat.  Experimental results reveal the wind turbine blades started producing power at a cut-in wind speed of 3m/s. The maximum power achieved during the testing process was 900W at a hub wind velocity of 9m/s. This is lower than the expected 1000W theoretical power output due to not perfect workmanship in the manufacture of the wind turbine blades. This study will help in building local manufacturing facilities and enhance rural electrification through off-grid technologies

Clinical Profiles of Cardiovascular Diseases and Predictors of Outcome of Hospitalization in a Tertiary Teaching Hospital, Ethiopia: A Prospective Observational Study

Abraha Hailu,1 Kibreab Gidey,1 Mohamedawel Mohamedniguss Ebrahim,2 Yonas Berhane,1 Teklay Gebrehaweria Baraki,1 Tesfay Hailemariam,1 Ataklti Negash,1 Habtamu Mesele,1 Tekleab Desta,1 Haylsh Tsegay,1 Mulubirhan Assefa,3 Alemayehu Bayray3 1Department of Internal Medicine, School of Medicine, Mekelle University-College of Health Sciences, Mekelle, Tigray, Ethiopia; 2Department of Biostatistics, School of Public Health, Mekelle University-College of Health Sciences, Mekelle, Tigray, Ethiopia; 3Department of Epidemiology, School of Public Health, Mekelle University-College of Health Sciences, Mekelle, Tigray, EthiopiaCorrespondence: Abraha Hailu, Department of Internal Medicine, Cardiology Unit, School of Medicine, Mekelle University-College of Health Sciences, Mekelle, Tigray, Ethiopia, Tel +251911413363, Email [email protected]: Documentation of cardiovascular diseases (CVDs) including major contributors to hospitalization and their outcomes in sub-Saharan Africa and Ethiopia is important to prioritize further research, prevention and treatment strategies.Objective: This study aimed to describe the clinical profiles of CVD admissions, risk factors, and patient outcomes at Ayder Comprehensive Specialized Hospital (ACSH) in Tigray, Ethiopia.Methods: Data of patients with the diagnosis of CVD was collected prospectively from Nov. 1, 2017 – Oct. 31, 2018 for patients admitted to medical wards and ICU of ACSH. Socio-demographic profiles, final admission diagnosis, duration of hospital stay and outcomes of hospitalization were variables recorded using a data abstraction checklist. Diseases were categorized using the World Health Organization’s International Classification of Diseases (ICD)-10 coding system. Data was analyzed using SPSS version 26.Results: Of the 2084 admissions over 1 year period, 767 (36.5%) had CVDs. The mean age of the study population was 53.4 ± 19.4 years with 55% females. Leading CVD admissions were stroke (35%), Venous thromboembolism (17%), rheumatic heart disease (RHD) (16.2%), ischemic heart disease (IHD) (11.3%) and cardiomyopathy (CMP) (7.4%). Heart Failure (HF) was found in 300 (39.1%) patients with structural heart disease. The structural cardiac lesions in those with HF were RHD (36%), CMP (19%), IHD (18%) and Cor pulmonale (9%). The in-hospital mortality of all CVD admissions was 13.2%. Of the total 101 CVD deaths most were because of stroke (n=37, 36.6%) followed by IHD (18.8%). Hypertension was the most frequent risk factor (28.8%).Conclusion: This study shows stroke to be the most common form of CVD and RHD to be the main reason for HF among hospital admissions in Northern Ethiopia, ACSH. Hypertension is the leading reported risk factor and hence the need to give high priority to hypertension and RHD control programs.Keywords: cardiovascular disease, admissions, outcomes, sub-Saharan Africa, Ethiopi