In this paper, a boost converter with a clamp circuit is proposed for high intensity discharge (HID) lamp application. The clamp circuit provides zero voltage turn on for both main and clamp switches. Compared to conventional boost converters, the proposed converter has the following advantages: (i) high voltage gain without suffering from extreme duty ratio, (ii) low stress on the switches and (iii) low switching losses. Simulation and experimental results show that the voltage stress on the switches are well within acceptable limits and prove the converter’s performance over a wide load range.

In this paper, a new driving method is presented for a magnetron bulb utilizing a phase-shifted active clamp fly-back converter. The converter is of a booster, isolated and high gain type. The active clamping structure is used to reduce the main transistor’ s voltage stress. By controlling the timing of the transistor clamp, the voltage required for the magnetron is adjusted. The main advantage of the proposed method is the simplicity of the control circuit of the magnetron lamp driver. In addition, the proposed method reduces the size, weight and price of the power transformer core. The power transformer leakage inductance has also been developed to provide a soft switching condition while reducing converter losses. The converter presents a maximum power of 1. 6 kW with an average power of 400 W, by setting the timing of the activation of the driving circuit. The design results are simulated and verified by PSCAD Simulink software.

In this paper, a ZVS interleaved flyback converter with two transformers is presented, which consists of two active clamp flyback converters and the main switch of one converter acts as an auxiliary switch of another converter. This converter has less auxiliary elements and less voltage and current stress compared to similar soft switching interleaved flyback converters. The introduction of a new auxiliary circuit for soft switching, in addition to increasing efficiency, minimizes the number of added semiconductors. Also, another advantage of this structure is the applicability of the provided auxiliary circuit to other isolated converters. The soft switching conditions in this converter are created by the auxiliary circuit in such a way that the converter switches turn on and off under ZVS conditions and the converter diodes turn on and off under ZCS conditions. The efficiency of the proposed ZVS interleaved flyback converter at full load is increased by 5%. Another advantage of the proposed converter is that the Q2 switch, in addition to providing zero voltage switching conditions for the Q1 switch, it also transmits energy and increases the density of the converter power and reduces the current stress. The converter is thoroughly analyzed and a 300W laboratory prototype is made to confirm its correct operation and practical results are presented.

A 64-year-old man was admitted to our hospital for chest pain. His previous medical history revealed hypertension, diabetes mellitus, and percutaneous coronary intervention (PCI) because of coronary artery disease. His physical examination was unremarkable. A 12-lead electrocardiography demonstrated normal sinus rhythm. Transthoracic echocardiography (TTE) showed a left ventricular ejection fraction of 50%. Additionally, the coronary angiography revealed a patent left main artery and 3 vessel disease. Therefore, the patient was candidated for elective on pump coronary artery bypass graft surgery. Under general anesthesia with standard monitoring, conventional median sternotomy was performed. In addition to the left internal mammary artery and saphenous vein grafts anastomosis of left coronary artery, a saphenous vein graft was anastomosed to right coronary artery (RCA). Subsequently, the patient was rewarmed and weaned off Cardiopulmonary bypass (CPB) without any problem. The operation was uneventful, and the patient was transferred to the open heart intensive care unit, where a portable chest radiograph (CXR) was immediately obtained. The CXR revealed a bulldog clamp on RCA (Figure 1-A). The patient was immediately transported to operative room. Under general anesthesia, the chest was opened via sternotomy again. The bulldog clamp was removed from the artery (Figure 1-B). After surgery, the patient was transferred to the open heart intensive care unit again. Immediately, another CXR was immediately obtained. The chest radiograph showed no abnormality. He was finally discharged home in a good overall condition. Although the forgotten foreign bodies (FBs) are rare after cardiac surgery, it is a serious problem. The most frequently foreign bodies are gauze pads, catheter pieces, surgical instruments and their parts. The rate of forgotten foreign bodies is one in 7000 surgeries...

Internal fixation of bone fracture is acommonmethod in the surgical treatment of fracture in long bones (1). Bridging the broken bone as well as obtaining a rigid fixation plays an essential role in proper healing (1). Several instruments can help orthopedic surgeons to preserve the alignment in an anatomical condition. Once the reduction is done, it can be maintained by internal fixation through the application of plate, screw, or other implants to recreate the normal anatomy of the fractured bone (1, 2). This study presents a new bone reduction clamp for easy insertion of the plate during internal fixation...