a model describing the main processes occurring in the uasb reactor was developed; in orderto maintain simplicity and applicability of the model, only the fundamental aspects were considered. in themodel, the reactor is divided in several well-stirred reactors coupled in series and it comprises substratedegradation, biomass growth and the reactions that take place within the granules. the impor...

abstract the propose of this study was evaluation of cropsyst model on growth simulation and yield stimation of canola under different irrigation treatments. canola (talaye) was sown under 5 treatment and 4 replicants in completed randomized block designs at the college of agriculture, shiraz universityduring 2007-2008. during the growth season dry mass and lai was meseaured frequently, then mo...

there are several theorical results about order statistics and copulas in the literature that have  been mentioned also by nelsen cite{p20}. the present study after reviewing some of these results, relies on  simulation technique to investigate the mentioned results about order statistics and copulas. the study concentrates on two well known archimedean gumbel and frank families in the case tha...

background: physical wedges are still widely used as beam modifiers in external beam radiotherapy. however the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. the aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

background: small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (imrt) and stereotactic radiosurgery (srs) treatments. accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. hence the ebt2 (external beam therapy) gafchromic film was used for dosimetry of sm...

Background: Stereotactic radiosurgery is an important clinical tool for the treatment of small lesions in the brain, including benign conditions, malignant and localized metastatic tumors. A dosimetry study was performed for Elekta ‘Synergy S ’ as a dedicated Stereotactic radiosurgery unit, capable of generating circular radiation fields with diameters of 1-5 cm at isocentre using the BEAM/EGS4...

Background: Recently, multileaf collimators (MLC) have become an important part of any LINAC collimation system because they reduce the treatment planning time and improve the conformity. Important factors that affect MLCs collimation performance are leaves material composition and their thickness.Objective: In this study, we investigate main dosimetric parameters of a typical MLC includi...