The daily global solar radiation data obtained from three Libyan locations, every one of them, it's located in different region, (Sabha- desert region), (Ghdames- middle region) and (Tripoli- Mediterranean region)...
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The daily global solar radiation data obtained from three Libyan locations, every one of them, it's located in different region, (Sabha- desert region), (Ghdames- middle region) and (Tripoli- Mediterranean region) were used to establish a relationship between daily diffuse fraction and daily clearness index K T . This relationship was compared with that established by Liu & Jordan, Stanhill, Choudhury, Erbs, and used to derive a correlation for the average daily diffuse fraction. Solar radiation and sunshine duration are intimately related phenomena, which was used to study the equation related of average daily radiation to the extraterrestrial radiation for location and average fraction of possible sunshine hours. Moreover the daily clearness index were calculated and the daily clearness index was used to estimate the frequency of occurrence of days with different values of K T and the cumulative frequency of occurrence of those days. Finally, the relationships for estimating the beam and diffuse components of daily global radiation were obtained using the previous mentioned author's model.
This paper is concerned with the processing technology of wind available data as a means to estimate the electricity generation in Derna site - Libya, which are located on the coast of Mediterranean Sea. The work pres...
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This paper is concerned with the processing technology of wind available data as a means to estimate the electricity generation in Derna site - Libya, which are located on the coast of Mediterranean Sea. The work presented long term wind data analysis in terms of annual, seasonal and diurnal variations at these sites. The wind speed and wind direction each 3 hours data for a period of 10 years between 2000 and 2009 were used in the analysis. Weibull parameters at different heights has been studied and used to describe the distribution and behavior of wind speed and their frequencies. Wind turbine energy production at different heights has been calculated using a Weibull distribution (Weibull Statistics Techniques). The total energy output per year from the wind machines of different sizes and at different hub heights were compared. This research work revealed that the lower rated speed for the wind energy conversion system (WECS) of the same height, the higher the capacity factor values, in most cases. This work used also a new analytical method of (Spena & Ahwide's method) for the estimation of the available wind energy potential. The results of both previous mentioned method's were compared. Moreover, the expected cost in $ Dollar/kWh for both wind machines have been calculated, which have different characteristics but the same power level of 1650 kW. It was hoped that the data analysis can help to identify good sites in Libya for new wind turbine installations. This evaluation was helpful to trigger the use of large wind turbines at the selected sites along the coasts of Mediterranean.
Most of the existing companies are seeking ways to increase their production efficiency. Attempts to reduce production costs are perfectly in line with this quest. Therefore, to establish an effective correlation betw...
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Most of the existing companies are seeking ways to increase their production efficiency. Attempts to reduce production costs are perfectly in line with this quest. Therefore, to establish an effective correlation betw...
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Most of the existing companies are seeking ways to increase their production efficiency. Attempts to reduce production costs are perfectly in line with this quest. Therefore, to establish an effective correlation between equipment maintenance and quality control to anticipate process downtime and bad quality losses can be very interesting in many ways. This paper initially tries to demonstrate the importance of the relationship between maintenance and quality. A methodological approach is then presented to evaluate the potential role of quality control in the improvement of maintenance policy. Finally, an industrial case study is briefly described and related conclusions are discussed.
Pipelines have been acknowledged as the most reliable, economic and efficient means for the transportation of gas and other commercial fluids such as oil and water. The designation of pipeline system as “lifelines” ...
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Pipelines have been acknowledged as the most reliable, economic and efficient means for the transportation of gas and other commercial fluids such as oil and water. The designation of pipeline system as “lifelines” signifies that their operation is essential in maintaining the public safety and well being. A pipeline transmission system is a linear system which traverses a large geographical area, and soil conditions thus, is susceptible to a wide variety of hazards. This pa-per is concerned with the dynamic behavior of buried town gas pipelines. A computer model with a finite number of nodes is created to simulate the behavior of the real gas pipeline. The dynamic susceptibility method is applied for twenty mode shapes of this model, which utilizes the stress per velocity method and is an incisive analytical tool for screening the vibration modes of the system. It can be readily identified, which modes, if excited, could potentially cause large dynamic stresses. This paper discusses also two of the piping dynamic analyses, namely the effect of the response spectrum of an earthquake and the time history analysis of a truck crosses the pipeline.
A process design CAE system to predict the laser sintered tool life has been developed. The prediction of laser sintered tool life is vital to satisfy the demand to prolong the die casting dies and designing longer to...
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ISBN:
(纸本)9781617382277
A process design CAE system to predict the laser sintered tool life has been developed. The prediction of laser sintered tool life is vital to satisfy the demand to prolong the die casting dies and designing longer tool life. In order to support new modern tool design analysis in rapid manufacturing trend, current limitation of tool life will be predicted by a strain-life based numerical approach. The general thermal fatigue equations are used to model the thermal cracking and predict the fatigue life of the laser sintered tool design process. Consequently, a strain-life diagram (S-N) were obtained, where fatigue life is defined in the plastic strain deformation of laser sintered tool design. Furthermore, the results from the numerical method models and literature were compared. With this new developed capability, an accurate predicting tool life creates new possibility for rapid die casting design.
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