introduction superficial x-ray therapy is one of the most important treatment methods in radiotherapy especially in the treatment of superficial skin lesions (up to 300 kvp). quality of the x-ray beam that can be expressed by half-value layer (hvl), are important indices for this type of treatment effective energy of photon and homogeneity coefficient (hc). materials and methods the hc of the s...

Introduction Superficial X-ray therapy is one of the most important treatment methods in radiotherapy especially in the treatment of superficial skin lesions (Up to 300 kVp). Quality of the X-ray beam that can be expressed by Half-Value Layer (HVL), are important indices for this type of treatment effective energy of photon and Homogeneity Coefficient (HC). Materials and Methods The HC of the s...

Usage of flywheel energy storage system (FESS) is a common method for frequency regulation due to its high power injection capacity and long life time. FESS is equipped by two back-to-back inverters including grid-side inverter and machine-side inverter. In conventional method, the machine-side inverter sets the active power and machine flux while grid-side inverter sets the reactive power and ...

when power systems are expanded and connected together with weak tie lines, the low-frequency oscillations are increased and the stability margin of the power system decreases. therefore, when designing the transmission system to be used, it is necessary to maintain the dynamic stability of the power system, and to make sure to have the most possible stability margin. sssc is a facts device con...

the paper presents a mathematical base modeling combined to modified-winding -function-approach (mwfa) for eccentricity fault detection of a round-rotor synchronous machine. for this aim, a 6-pole machine is considered, and the machine inductances are computed by mwfa in healthy and also under eccentricity fault. a numerical discrete-time method has been proposed to machine modeling in voltage-...

In this paper, using a personal computer (PC), the practical implementation of scalar and vector control methods on a three–phase rotor surface- type permanent magnet synchronous machine drive is discussed. Based on the machine dynamic equations and the above control strategies, two block diagrams are presented first for closed-loop speed controlling of the machine drive/system. Then, the desig...

background. acid etching prior to orthodontic bracket bonding may result in enamel wear or cracks following bracket removal. the manufacturer of fuji ortho lc glass-ionomer (gi) claims that it can bond brackets to wet unetched enamel. this study aimed to compare the bracket bond strength to etched and unetched enamel under dry and wet conditions. methods. in this in vitro study, 60 intact premo...

the amount and consistency of the applied forces to the tooth are important factors in tooth movements; therefore, the aim of this study was to compare the initial force and the force loss of three brands of elastics in 24 hours.in this in-vitro study sixty non-latex elastics (3/16 medium) from three companies (forestadent, dentaurum and ortho technology) were randomly selected. two static test...

A new type of single-phase stand-alone induction generator using a three-phase induction machine and a single-phase voltage-source PWM inverter is introduced. The generator scheme is capable of producing constant load frequency with a very well regulated output voltage. A small lead acid battery and a single-phase full diode-bridge rectifier are used to feed the inverter. The inverter feeds one...