Production of Fe-C alloy powders by mechanical alloying was studied. Fe and graphite elemental powder mixtures containing 0.8 and 1.5wt.% graphite were mechanically alloyed using a planetary ball mill. The structural changes of powder particles during mechanical alloying were studied by x-ray diffractometery, scanning electron microscopy and microhardness measurements. For both compositions, me...

abstract producing of flowers and ornamental plants in iran has some challenges and failure in the market structure and marketing of these products. in this study, we evaluated the different marketing channels of flowers and ornamental plants in the existing market structure according to economic criteria and the characteristics of market structure. cut-rose and esfahan province were selected a...

greenhouse structure has an important role in success of greenhouse production. this research was conducted to study problems related to vegetable greenhouse structure in khuzestan province for on year(2011-2012). for this purpose, 21 greenhouses were selected by simple randomized samplang and questionnaires were completed. the results revealed that the major problems in greenhouses vegetable p...

This paper deals with the problem of optimizing two-stage structure decision making units (DMUs) where the activity and the performance of two-stage DMU in one period effect on its efficiency in the next period. To evaluate such systems the effect of activities in one period on ones in the next term must be considered. To do so, we propose a dynamic DEA approach to measure the performance of su...

this paper shows the role of the general dynamic model in empirical research of production technology in agriculture. the model is a first order autoregressive multivariate specification, first developed by anderson and blundell. this model is general enough to nest several simpler dynamic as well as static models within it. therefore, it provides a framework for applying classical testing ...

this paper deals with the problem of optimizing two-stage structure decision making units (dmus) where the activity and the performance of two-stage dmu in one period effect on its efficiency in the next period. to evaluate such systems the effect of activities in one period on ones in the next term must be considered. to do so, we propose a dynamic dea approach to measure the performance of su...