Design and Simulation of a Solar Energy System for Desalination of Brackish Water

In light of a sort of crisis of water scarcity which begins to loom worldwide as well as the economic constraints for achieving sustainable development, it becomes essential to find appropriate solutions to face this challenge. Morocco, which has considerable brackish water resources and an important solar resource deposit, is required to use desalination techniques; however, the reliability of such techniques can no longer be applied just in terms of their value as renewable sources of energy. The solution presented in this publication, establishes a rather reliable way to produce drinking water. The technique of desalination by reverse osmosis is considered in this study to be a promising technique. The objective of our study is the implementation of a prototype for desalination of reverse osmosis, which is a low-cost small unit used to treat brackish water based on solar energy

ST-elevation myocardial infarction complicated by ventricular tachycardia revealing coronary artery ectasia: a case report

Abstract Background Coronary artery ectasia is a rare angiographic finding and results from a disease process that compromises the integrity of the vessel wall. Its prevalence ranges between 0.3% and 5% of patients undergoing coronary angiography (Swaye et al. in Circulation 67:134–138, 1983). Coronary artery ectasia in patients with ST-elevation myocardial infarction is associated with an increased risk of cardiovascular events and death after percutaneous coronary intervention. Case presentation We report the case of a 50-year-old male Caucasian patient, admitted for ventricular tachycardia at 200 beats per minute hemodynamically not tolerated that was reduced by external electric shock. Electrocardiogram after cardioversion showed a sinus rhythm with anterior ST-elevation myocardial infarction. Thrombolytic therapy was chosen after exposure to dual antiplatelet therapy and heparin since the expected time to percutaneous coronary intervention was greater than 120 minutes from first medical contact and the patient presented within 12 hours of onset of ischemic symptoms. The electrocardiogram after thrombolysis showed the resolution of the ST segment. The echocardiogram showed a dilated left ventricle with severe dysfunction with left ventricle ejection fraction at 30%. Coronary angiography revealed non-obstructive giant ecstatic coronaries without any thrombus. A check-up to look for possible etiologies for coronary artery ectasia was carried out and returned normal. Since no etiology for coronary artery ectasia was found at the limit of available exams in our center, the patient was discharged with antiplatelet therapy (aspirin 100 mg once a day) and heart failure treatment with an indication for an implantable cardiac defibrillator. Conclusions Coronary artery ectasia in the context of acute myocardial infarction is a rare condition that may have dangerous complications, especially when an optimal treatment for ecstatic culprit vessels is still controversial

Study of electrical properties of Al/Si 3 N 4 / n -GaAs MIS capacitors deposited at low and high frequency PECVD

International audienceAs for silicon, surface passivation of GaAs and III-V semiconductors using silicon nitride (Si 3 N 4 ) deposited by plasma enhanced chemical deposition (PECVD) is widely used to improve devices and circuits stability, reliability and for encapsulation. In this work, the effect of plasma excitation frequency in the PECVD reactor on the surface passivation efficiency of GaAs during Si 3 N 4 deposition was investigated. Metal-Insulator-Semiconductor (Al/Si 3 N 4 / n -GaAs) capacitors are fabricated and characterized using capacitance–voltage ( C – V ), and conductance–voltage ( G – V ) to compare electronic properties of GaAs/Si 3 N 4 interfaces depending on the use of a high frequency PECVD (HF-PECVD) or low frequency (LF-PECVD) process. The drastic advantage of using the LF-PECVD technique for the passivation of GaAs is clearly demonstrated on the characteristic C – V at 1 MHz where a good surface potential was observed, while a quasi-pinned surface Fermi level was found when HF-PECVD was used. To unpin Fermi level, a sulfur pre-treatment prior before HF-PECVD deposition and post-metallisation annealing were necessary. A lower frequency dispersion and a lower hysteresis indicating low densities of slow traps were observed for MIS devices fabricated by LF-PECVD. The advantage of having an efficient passivation without sulfur treatment is important since ammonium sulfide used for this purpose is corrosive and difficult to adapt in industrial environment. The better electronic properties of GaAs/Si 3 N 4 interface were found for silicon nitride layers using LF-PECVD deposition. This can probably be associated with the high-level injection of H + ions on the semiconductor surface reducing thus the native oxides during the initial steps of dielectric deposition