more than one percent of the labor force in each country consists of welders exposed to various damages caused by welding. the number of studies conducted in this field is low, especially in iran. in this paper, we tried to discover any temporary and reversible obstructive effect of welding fumes on the respiratory systems of welders. in this cross-sectional study, peak expiratory flow rates an...

The effect of the volume flow rate of the heat transfer fluid (air) on the thermal parameters of the solar air collector with a single air pass without using fins under the absorbing plate have been investigated experimentally and theoretically. We use a new design of solar air collector which aims to optimize these parameters in the region cited above. Our solar air collector was realized at t...

administrative regulations for water flow decrease distribution efficiency and effect the economical operation of irrigation networks. complications in distribution systems and the decrease in availability of water require study of the hydraulic performance of existing flow control structures. control systems designed by neyrpic (zayandeh rud network) and usbr (doroodzan network) were investiga...

The single-phase flow and thermal performance of a double pipe heat exchanger are examined by experimental methods. The working fluid is water at atmospheric pressure. Temperature measurements at the inlet and outlet of the two streams and also at an intermediate point half way between the inlet and outlet is made, using copper-constantan thermocouple wires. Mass flow rates for each stream are ...

background: measuring peak expiratory flow rate has been suggested as an important tool in asthma management by all international guidelines.   objective: studies on various populations have shown considerable variations in normal values of peak expiratory flow rate. since reference standards for iranian children are not available, the present study was performed to establish these standards.  ...

For a long period of time, design and manufacturing technology of high flow rated vertically suspended pumps (VSPs) which have an extensive applications in many industries such as water and wastewater, mining, petrochemical and oil and gas industries, used to be imported from European countries. For the first time in Iran's pump industry, with the support of Ministry of Petrochemical[ah1]  and ...

In the most application of nozzle with gas-liquid two-phase flow, the quality of mixture in exhaust of nozzle is the most important parameter as well as the flow velocity. On the other hand, in some industrial application, such as water injection in forced induction (turbocharged or supercharged) internal combustion engine the spray quality is the main goal of designing. In this case and for im...

Cavitation is among the most complicated and common damages of spillway structures. This phenomenon is controlled by different parameters including the pressure, flow velocity, spillway surface material, operation time, and air flow content. The cavitation index is calculated along the spillway and compared with its critical value using the measured values of the flow’s hydraulic parameters. Th...