The study of the battery charge process as the only power storage agent in off-grid systems is of significant importance. The battery charge process has different modes, and the battery in these modes is dependent on the amount of charge. In order to charge the battery in off-grid systems, two charge controllers including Pulse Width Modulation (PWM) and Maximum Power Point Tracker (MPPT) are c...

The discussions carried on last year in the Medical Society of New York, regarding yellow fever, are well worth the attentive study of our readers. Drs. Austin Flint, J. C. Peters, G. M. Smith, and, in fact, by far the majority of the best known authorities who took part in the debate, were of opinion that yellow fever was not a contagious disease. Nevertheless, they believed in its " portabili...

Due to geographic and climatic conditions in mountainous northwest area, Roads in these areas are often covered with snow, ice and mud. Hence Transportation of equipment and soldiers encounter hardship and difficulties in rural area and specially outposts. To solve these problems, it is needed to fabricate portable roadway or traction mats. These high strength mats cover surface of roads and ar...

BACKGROUND Portable oxygen devices simplify and facilitate patient therapy. This study was designed to compare S(pO2) and patient satisfaction with a portable oxygen concentrator or a combined system consisting of a fixed device with continuous-flow oxygen dispensation and a portable device with pulse dispensation for ambulation. METHODS This crossover trial assessed 25 subjects with COPD (92...

Mechanical ventilators used in intensive care units are sophisticated devices. The guiding principle in their design is the provision of optimal lung ventilation. They incorporate precise but sizeable pneumatic components intended to utilize piped gases and mains electricity. However, when transporting patients receiving ventilatory support, these devices are rarely suitable because of their si...