Abstract The aim of this study is to assess the wind energy potential and to compare Weibull and the Maximum Entropy Principle (MEP) distributions, with meteorological measured data. Dernah is selected site, which has good wind characteristics (seasonal, monthly and diurnal wind speed variations and wind direction variations), for possible wind energy applications. The data source is measured at an elevation of 40 m above the ground level for one year period (2003), and it is analyzed statistically. The functions of probability density and power density are calculated using the Weibull and MEP distributions. The Lagrangian multipliers of MEP distribution are estimated numerically at r values of 0 to 5 by using Newton Raphson, Simpson’s rule and Romberg’s methods. The MATLAB simulation is also applied for estimating Lagrangian multipliers. The verification of the results is also assessed by Maple software. The statistical analysis parameters based on wind speed and power density are used as the suitable judgment criterion for the distribution functions. It is found that for MEP distribution, the wind power (W/m2) 450, 395 and 407, are for the cold season, the hot season and for the year 2003, respectively. However, there is no significant difference of the presented peak values of the results in this study for Weibull and MEP distributions. Such result can be attributed to the fact that the average wind speeds were relatively high and the calm spells are about 7% in the year 2003 data.
جبريل يوسف الفيتوري (2010)

شهدت مدينة طرابلس الكبرى قفزة نوعية في العديد من التعاقدات لتنفيذ مشاريع تنموية في البنى التحتية والاسكان وما يتطلب من مشاريع مرافقة إلا أنها في الآونة الاخيرة ومع بداية هذا العقد عانت أغلب تلك المشاريع من العديد من المشاكل، مما انعكس سلباً على كافة مراحل التنفيذ، لذلك تم القيام بهذه الدراسة هذه الدراسة للوقوف على أسباب التأخير في تلك المشاريع، وبالتالي العمل على إثراء المكتبة الليبية بالبحوث الميدانية التي تتناول موضوع أسباب التأخير في إكمال المشاريع الإنشائية، ويمكن أن تلفت الدراسة الحالية اهتمام الباحثين إلى معرفة الاسباب والتي أدت إلى التأخير في المشاريع، ودراسة كل سبب من ناحية ظروف حدوثه، وأهم النتائج المؤثرة سلبا على المشروعات، ونسق مساهمتها في التأخير، ومن خلال هذه الدراسة تم التعرف على الأسباب التي أدت للمساهمة في عرقلة تنفيذ المشاريع ببلدية طرابلس الكبرى، لأجل التركيز عليها مستقبلاً بهدف تفادي حدوثها. arabic 177 English 0
رجب عبدالله عبدالقادر حكومة, عبدالوهاب احمد دريبيكة(1-2019)

Abstract The contribution of this thesis is to improve the understanding of acoustic dynamics in the audio duct with HQ (Herschel-Quincke tube) is essentially a hollow side-tube that travels along a main-duct axis and attaches to the main-duct at each of the two ends of the tube. In this project the detailed measurements of acoustic in a duct with HQ induced by a loudspeaker at various frequencies have been carried out experimentally. Two microphones have been used to measure the net acoustic power transmission in the duct downstream of HQ and compared with the net acoustic power transmission in the duct without the HQ. Two types of HQ and three different ducts have been studied. The acoustic wave signals are traveling in the duct as a plane wave these waves are generated by a signal generating system with a known sinusoidal wave (sine wave). One of the microphones is located just before the HQ-duct interface and the other microphone after the HQ in the duct. Labview software is used to analyze the signals with a sampling rate of 44100s/sam and number of samples is 20000. This study makes an exhaustive understanding of power spectrum of two acoustic channels in the duct with and without HQ. The results show that there is a great potential for HQ tube system to attenuate the noise over conical and cylindrical sections. The sound attenuation on conical section with short HQ shows about 70% and that of cylindrical section a meager 47% at higher frequency. Further more the sound attenuation of cylindrical section with long HQ is occurred at low frequencies.
رضوان نجمي الكوني الشريف (2010)