Background: This study aims to calculate the air-kerma strength (SK), the dose rate constant (∧) and the dose rate profiles of a Gammamed 12i Ir-192 source by using the Monte Carlo technique and to compare the dose rate values with those calculated by the Abacus HDR treatment planning system (TPS). Materials and Methods: Air-kerma strength (in units of U; 1 U= μGy m2 h-1) and the dose ra...

A battery charging circuit, which operates as a constant power source, is proposed in this paper. By maintaining a constant output power throughout the charging process, the circuit reduces the size of thermal installation which would normally be required in the cases of constant-voltage or constant-current charging. The proposed circuit takes the form of a half-bridge converter with an additio...

This paper proposes a pulsed power generator which consists of two types of switched-capacitor booster modules. A doubling mode module employed to elevate the input voltage to a specified level and, constant mode module is used to increase the elevated voltage into the finally intended bipolar output voltage. Also, the proposed modular structure does not utilize any switches across the load. Ot...

In this paper, an unmanned aerial vehicle (UAV) assisted cooperative communication system is studied, wherein a source transmits information to the destination through an energy harvesting decode-and-forward UAV. It is assumed that the UAV can freely move in between the source-destination pair to set up line of sight communications with the both nodes. Since the battery of the UAV may be limite...

The sum-capacity of a static uplink channel with single-antenna sources and an -antenna destination is known to scale linearly in , if the random channel matrix fulfills the conditions for the Marcenko-Pastur law: if each source transmits at power , there exists a positive , such that almost surely. This paper addresses the question to which extent this result carries over to multi-hop networks...

This work presents an ultra-low power oscillator designed for wake-up timers in compact wireless sensors. A constant charge subtraction scheme removes continuous comparator delay from the oscillation period, which is the source of temperature dependence in conventional RC relaxation oscillators. This relaxes comparator design constraints, enabling low power operation. In 0.18µm CMOS, the oscill...

wind power has been widely considered in recent years as an available and a clean renewable energy source. the cost of wind energy production is currently the main issue, and increasing the size of wind turbines can reduce wind energy production costs. hence, megawatt wind turbines are being rapidly developed in recent years. in this paper, an aerodynamic analysis of the nrel 5mw turbine is car...

This paper proposes a new single phase transformerless Photovoltaic (PV) inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC) tec...

In this paper, a low-power adaptive low noise amplifier (LNA) is presented. The LNA is based on a bipolar cascode topology, uses inductive source degeneration and emitter area scaling to achieve noise and input-impedance matching simultaneously. The input impedance and the noise factor were simulated as function of the bias collector current and the results show that both are approximately cons...