the musculoskeletal disorders cover a large percent of occupational diseases; therefore, in order to protect workers from such disorders, there is a need to evaluate workers positions at work in different industries. in a major furniture manufacture located in tehran, 500 workers were examined. these workers were divided into fourteen working groups, including production lines of water-heater, ...

Air-flow measurements at the working aperture showed an air speed of 0-137 m/second. After panels had been fitted to reduce the aperture from 84 x 13 cm to the minimum practicable size of 31 x 13 cm, the flow was increased to 0-32 m/second-still less than the recommended rate of 0 5 m/second. Tests of the furnace efficiency (Table, plates 1-4) showed that viable Str. hominis survived in the eff...

In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO2 enrichment (6...

Thermo-hydraulic performance of a Double Pass Parallel Flow Solar Air Heater (DPPFSAH) roughened with perforated multi-V ribs has been studied experimentally in prior study and the effect variation open area ratio change relative roughness width analysed reported. The current work builds upon aforementioned earlier by discussing detail methodology various steps involved development correlation ...

In the present study, the conjugate turbulent free convection with the thermal surface radiation in a rectangular enclosure bounded by walls with different thermophysical characteristics in the presence of a local heater is numerically studied. The effects of surface emissivity and wall materials on the air flow and the heat transfer characteristics are the main focus of the present investigati...

This paper demonstrates a number of PI controller tuning methods being used to tune a temperature controller for a real air heater. Indices expressing setpoint tracking and disturbance compensation and stability margin (robustness) are calculated. From these indices and a personal impression about how quick a method is to deliver the tuning result and how simple it is to use, a winning method i...

This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dy...

Compressed air is widely used in enterprises, and it possible to reduce consumption on pneumatic devices by heating. Most often, heating carried out shell-and-tube heat exchangers. To increase the area of exchange between medium air, finned tubes are used, which can significantly volume occupied heater. The design heater influenced many factors, importance influence each them differ significant...

Solar radiation is harnessed as an alternative energy source for numerous industrial and domestic applications. Currently, apart from space heating, air-conditioning lightning, solar water heating (SWH) systems have a widespread usage applications in both sectors. The major issue with that the transmission efficiency low so heat transfer augmentation methods can be used to improve thermal perfo...