a three stage production system is considered in this paper. there are two stages to fabricate and ready the parts and an assembly stage to assembly the parts and complete the products in this system. suppose that a number of products of different kinds are ordered. each product is assembled with a set of several parts. at first the parts are produced in the first stage with parallel machines a...

the problem of staff scheduling at a truck hub for loading and stripping of the trucks is an important and difficult problem to optimize the labor efficiency and cost. the trucks enter the hub at different hours a day, in different known time schedules and operating hours. in this paper, we propose a goal programming to maximize the labor efficiency via minimizing the allocation cost. the propo...

to use services transparently in a distributed environment, the utility grids develop a cyber-infrastructure. the parameters of the quality of service such as the allocation-cost and makespan have to be dealt with in order to schedule workflow application tasks in the utility grids. optimization of both target parameters above is a challenge in a distributed environment and may conflict one ano...

liquid-phases adsorption equilibrium of phenol onto two naturally available soils namely kalathur soil (kr) and adhanur soil (ar) were studied. the experimental data were analyzed using fourteen isotherm models, ranging from single-parametric model to multi-parametric models (up to 5 parameters) of the system. results show that in general the accuracy of models to fit experimental data improves...

the present research aims to apply several approaches for suitability evaluation of lands under cultivation ofalfalfa and barley in chaharmil mechanized farming center, ardestan town, isfahan province, iran. climatic andsoil maps of the climate and soil data were provided in raster format. land evaluation carried out using maximumlimitation, parametric and multi-criteria (analytical hierarchy p...

an important concern in rock mechanics is non-homogeneity as joints or fault. this noticeable feature of failures in rock is appearance of slip surfaces or shear bands, the characteristics of that are associated with deformation being concentrated in a narrow zones and the surrounding material remaining intact. adopting the joints as fractures, fractures are well known for their effects on the ...

cucumber is one of the main vegetables in iranian food basket. a wide range of pesticides are used for crops protection during the cultivation of vegetables such as cucumber due to heavy pest infestation. analysis of pesticide residues in food and other environmental commodities have become essential requirement for consumers, producers, and food quality control authorities. this study was aime...

abstract       background and objective: enterococci are relatively nonvirulent bacteria that rarely cause disease. antimicrobial treatment of enterococci is often challenging due to their antibiotic resistance. this study aimed to investigate the antibacterial activity of aqueous extract of garlic against enterococcal isolates.     methods: in this descriptive study, 120 enterococcus isolates ...

background: functional appliances such as bionator have been used to treat class ii malocclusion. the purpose of this study was to compare the skeletal, dental and soft tissue effects of bionator appliances with multi-p (a newly developed appliance) in the treatment of class ii malocclusion. subjects and methods: 45 class ii children were chosen and randomly assigned to either the bionator or m...

background: a high prevalence of human t-cell lymphotropic virus type 1 (htlv-1) infection among general population in the northeast of iran has been reported. multi-transfused patients are known as ‘at-risk’ group for the infection. this systematic review and meta-analysis was conducted to estimate the prevalence of htlv-1 infection among iranian multi-transfused patients. materials and method...