aquaculture is among the oldest occupations of human being. over the past quarter of century, the aquaculture industry has grown rapidly. the effect of water containing sodium sulfate on long term compressive strength of concrete of fishing ponds and channels is investigated in this paper. aim of this paper was to analyze the strength of concrete channels and of aquaculture which are in direct ...

Constructed wetlands have become a good alternative to urban and industrial wastewater treatments. Because of the many interactions between the different parts that form the wetland, the design of these systems used to be very complex so a good design tool is required. Hybrid constructed wetlands mix the aerobic and anaerobic properties of vertical and horizontal subsurface flow constructed wet...

mix cropping of alfalfa (medicago sativa) and annual ryegrass (lolium rigidum) may improve forage production in the rangeland and field conditions, especially in spring after the establishment year. in this study, the effects of different sowing rates of alfalfa and annual ryegrass seeds in the replacement and additive series of mix cropping were evaluated on forage yield in first year after th...

introduction: quality of services extremely depends on how personnel have contact and interaction with the clients. moreover, the personnel’s attitudes and their behaviors with the clients significantly affect clients’ perception of quality of services and consequently influence their satisfaction as well as their absorption to the services of an institution. this study intends to investigate t...

the strength of concrete is a function of the proportions of the constituent materials, namely, cement, water, fine and coarse aggregates. the conventional methods used to determine the mix proportions that will yield the desired strength, are laborious, time consuming and expensive. in this paper, a mathematical method based on modified regression theory is formulated for the prediction of con...