aims: the aim of the present work is (1) to evaluate dose calculation accuracy of two commonly used algorithms for 15 mv small photon fields in a medium encompassing heterogeneity and (2) compare these results with measured results obtained using gafchromic film ebt2. materials and methods: authors employed kailwood (pinus wallichiana) to mimic lung. briefly, seven kailwood plates, each measuri...

in this paper we focus on a continuously deteriorating two units series equipment which its failure can not be measured by cost criterion. for these types of systems avoiding failure during the actual operation of the system is extremely important. in this paper we determine inspection periods and maintenance policy in such a way that failure probability is limited to a pre-specified value and ...

background: high density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. over the past eight years, some efficient galena-based concrete samples for shielding x or gamma rays was produced. the goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. materials an...

background: the characteristics of secondary neutrons in a high energy radiation therapy room were studied using the mcnpx monte carlo (mc) code. materials and methods: two mc models including a model with full description of head components and a simplified model used in previous studies were implemented for mc simulations. results: results showed 4-53% difference between full and with the sim...

deregulation policy has caused some changes in the concepts of power systems reliability assessment and enhancement. in this paper, generation reliability is considered, and a method for its assessment using intelligent systems is proposed. also, because of power market and generators’ forced outages stochastic behavior, monte carlo simulation is used for reliability evaluation. generation reli...

wind power generation is variable and uncertain. in the power systems with high penetration of wind power, determination of equivalent operating reserve is the main concern of systems operator. in this paper, a model is proposed to determine operating reserves in simultaneous market clearing of energy and reserve by stochastic programming based on scenarios generated via monte carlo simulation ...

abstract background: accurate methods of radiation therapy dose calculation. there are different monte carlo codesfor simulation of photons, electrons and the coupled transport of electrons and photons. mcnpis a general purpose monte carlo code that can be used for electron, photon and coupledphoton-electron transport.monte carlo simulation of radiation transport is considered to be one of the ...

Introduction: Monte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) M...

we compare two approaches for a markovian model in flexible manufacturing systems (fmss) using monte carlo simulation. the model which is a development of fazlollahtabar and saidi-mehrabad (2013), considers two features of automated flexible manufacturing systems equipped with automated guided vehicle (agv) namely, the reliability of machines and the reliability of agvs in a multiple agv jobsho...

background: iodine brachytherapy sources with low photon energies have been widely used in treating cancerous tumors. dosimetric parameters of brachytherapy sources should be determined according to aapm tg-43u1 recommendations before clinical use. monte carlo codes are reliable tools in calculation of these parameters for brachytherapy sources. materials and methods: dosimetric parameters (dos...