in this study, preparation of nano-sized gamma alumina with high specific surface area and high yield by thereaction between aluminum nitrate and sodium carbonate, without using any surfactant is reported. bohemite (aluminum oxyhydroxide) was prepared as a precursor by strict control of ph and reaction temperature. the gel produced was purified by washing followed by centrifugation. the specifi...

Gossiping is one of the most crucial applications in Wireless Sensor Networks (WSNs) which has been the focus of many researchers. A main issue of gossiping is how to assign timeslots to nodes for interference-free data transmission. There are three models concerning gossiping in WSNs: unit-sized, bounded-sized, or unbounded-sized messages. For these models, the problem of constructing minimum ...

the objective of this paper is to determine the efficiency of manufacturing companies in kenya over the period of 2009 to 2011 as well as suggesting appropriate policies to be employed by the manufacturing companies in kenya based on the findings of the study. three critical inputs variables (raw materials, staff expenses and plant and machinery) and two output variables (net sale and earnings ...

Medium-sized and small enterprises play a key role in the process of economic and social development of countries around the world. In our country, the problem of financing difficulties that medium-sized and small enterprises are face with has become the main influence factors, thus blocking the medium-sized and small enterprises further development. To strengthen the study of medium-sized and ...

The effect of using coarse grain in the upper layer of a gravel-based reed bed is investigated. The aim for testing the “anti-sized” arrangement of gravel media is to seek a solution for the practical problem of medium clogging in reed beds that frequently takes place during the treatment of high strength wastewaters. Results from parallel operations of an anti-sized and a conventional “monosiz...

development of modern economy without private sector and high vigilance entrepreneurs is vital to identify opportunities and use of opportunities around the world. in this regard, identifying the influencing factors on emergence and development of entrepreneurship culture can be effective to promote entrepreneurship in our country. for this purpose, the main issue in this study is to identify t...

Scheduling is a capital problem when using distributed heterogeneous computing (HC) and grid environments to solve complex problems. The scheduling problem in heterogeneous environments is NP-hard, so a significant effort has been made to develop efficient methods for solving the problem. However, few works have faced realistic grid-sized problem instances. This work presents a parallel CHC (pC...

In this paper, a genetic algorithm is presented for an identical parallel-machine scheduling problem with family setup time that minimizes the total weighted flow time ( ). No set-up is necessary between jobs belonging to the same family. A set-up must be scheduled when switching from the processing of family i jobs to those of another family j, i  j, the duration of this set-up being the sequ...