Every day, approximately half a million workers in the construction sector in Egypt are exposed to excessive noise. Noise is one of the most prevalent physical contaminants in the construction sector. The most negative effects of noise exposure are related to the hearing system and may produce occupational deafness or even permanent deafness. These effects have a very important influence on people’s health and well-being. The goals of this study are to carry out measurements to evaluate construction noise levels, which exceed the permissible level set by Egyptian noise standards and policy to protect the public health of workers, to assess noise exposure, and to develop controls for proposing preventive solutions. The noise levels to which the workers in the construction sector are exposed have been studied. A number of representative measurements have been carried out using a sound level meter and a dosimeter to collect data from workers devoted to different tasks in the construction process. The most important levels and indexes have been analyzed with those data.

This study concerns road traffic noise in Alexandria, the second biggest city in Egypt. Goals of this study are to carry out measurements to evaluate road traffic noise levels, are these levels exceeded permissible noise levels set by Egyptian noise standard and policy to protect public health. To carry out restrictions to reduce noise levels for improving environmental conditions. Measurements taken for traffic noise levels, indicates that noise levels are higher than those set by Egyptian noise standards. Ldn = 80 dB and higher were recorded, while maximum permissible level is 60 dB. Ldn are calculated for 22 locations spread over different urban zones of city. It was found out that 95.5 % out of locations display Ldn are over 65 dB. 86.4 % out of total number of locations their Ldn are over 70 dB. Results of restrictions found that (i) in absence of horns, Ldn decreased at all sites reduction was 11.2 dB occurred in downtown area. (ii) In absence of horns, trucks and buses reductions in Ldn range between 6.2 to 14.3 dB. This shows that town planner can use various strategies to change traffic composition in order to achieve quieter city environments.

Cairo is the eleventh biggest city in the world and the capital of Egypt. Annoyance of workers from Cairo international airport noise levels was studied. 260 workers at 20 selected locations with different noise levels in offices, arrival, and departure halls were evaluated. The goals of this study are to carry out measurements to evaluate noise levels within airport, are if these levels exceeded the permissible levels set by Egyptian noise standard and policy to protect public health of workers?, to carry out experiments to reduce airport noise levels as: effect of distance from runway, numbers of movements, and types of aircrafts, to examine worker's attitudes towards airport noise, to know the relationship between airport noise levels and degree of annoyance. The results of the measurements showed that aircraft noise level inside building were 84 dB. Annoyance of respondents showed that 42.8 % were highly annoyed, 4.6 % their hearing were harmed. There was a strong relationship between airport noise levels and percentage of highly annoyed respondents. By increasing airport noise level possibility of workers to make mistake in their work was also increased

ecently, it is predicted that the fossil fuels will be sufficient for a few decades at the present extraction rates. So, the performance studies of the internal combustion engines play an important role to achieve the best operating point at different weather temperatures. In the present study, the effects of the inlet air temperatures on the engine performance characteristics were studied at different cooling loads. Several experiments were carried out on a single cylinder diesel engine (SCDI). The performance characteristics of SCDI included: brake power, specific fuel consumption, brake thermal efficiency and exhaust emissions (carbon dioxide, CO2, carbon monoxide CO, and hydrocarbon HC). The findings show that the inlet air temperature and cooling conditions have appreciable effect on the performance characteristics of the SCDI especially at low cooling rate. It can be concluded that the high cooling rate leads to the enhancement in the brake thermal efficiency, the b.s.f.c, and the emitted CO2, CO, and HC. On the other hand the high cooling rate leads to the decrease in the volumetric efficiency. So, a compromising between the inlet air temperature and the cooling rate should be recommended for the engine best performance.

Gas turbine cycle technologies will play a major role in future power generation, and several well-justified concepts have been developed or are the subject of major feasibility studies. In the present work, gas turbine cycles are modified with steam injection between the combustion chamber exit and the gas turbine inlet. Heat recovery steam generators, utilizing the exhaust gases, provide these cycles with the injected steam at saturated vapor. The thermodynamic characteristics of the various cycles are considered in order to establish their relative importance to future power generation markets. The irreversibility of the different composing units of the cycles and the variation of gas properties due to steam injection as well as changes in the interrelation of component performance parameters are taken into account. The isentropic temperature ratio and maximum to minimum cycle temperature ratio are varied over some ranges that slightly exceed their practically acceptable bounds in order to comprehensively investigate their effects on cycle characteristics. The performance characteristics for various modified and regeneration cycles are presented at the same values of the operating parameters. The present modified cycles with steam injected cycles achieve an additional power output and higher efficiencies, resulting in a lower specific cost. At the chosen values of the operating parameters, the enhancement achieved in the overall efficiency for the simple, reheat (with steam injection at high and low pressures) and partial oxidation (with steam injection at high and low pressures) gas turbine cycles are of about 20–30%, 120–200%, 10–12%, 120–260% and 20%, respectively. The present modified cycles technique can be considered among the possible ways to improve the performance of gas turbine cycles-based power plants at feasible costs. This concept can be used for similar core engines. Copyright © 2011 John Wiley & Sons, Ltd.