Abstract During the last years there has been an increasing consciousness of the environmental problems, created by the use of fossil fuels in electrical power generation consumed by converting cooling systems. In addition, the use of common working fluids (refrigerants), with their ozonedepleting and global warming potential, has become a serious environmental problem. This underlines the need to implement advanced, new concepts in building air-conditioning. The most common global type of thermally driven technology to produce chilled water is absorption cooling. For air-conditioning applications, absorption systems commonly use the water/lithium bromide or ammonia/water as working pair of fluids. The objective of this study is to establish a fundamental basis for further research and development within the field of solar cooling. In this study, an overview of possible systems for solar powered refrigeration and airconditioning systems will be presented. The concept of the ‘Solar Cooling Path’ is introduced, including a discussion of the energy source to the collector. Brief information and comparisons of different absorption refrigeration cycles are also presented. A solar-driven absorption refrigeration system has been selected as a case study for a further detailed investigation. A low temperature heat source can be used to drive the absorption refrigeration cycle, making the system suitable for integration with solar thermal collector. The Transient System Simulation program (TRNSYS) and Engineering Equation Solver (EES) simulation tools are used to model and analyze the performance of a solar-driven absorption refrigeration system. Analysis of the absorption cycle system is initiated by steady-state analysis. A modeling of single effect water/lithium bromide absorption cycle was constructed to study the effect of the operating variable on the system performance and to determine the optimum operating conditions for the absorption cycle. This model was developed by Engineering Equations Solver program (EES). In practice, the ambient conditions and solar radiation are not constant. Therefore, a dynamic analysis is useful for determining the characteristics of the system during the entire year, and dimensioning the important components of the solar collector subsystem, such as storage tanks and collector area. The overall solar absorption cooling system has been simulated by the TRNSYS program with a typical meteorological year file containing the weather parameters for the capital of Libya, Tripoli. Finally, a parametric study was carried out to investigate the influence of key parameters on the overall system performance of solar absorption cooling system and hence to improve and optimize the system design. Results from the parametric optimization indicated that with an area of 130m2 of flat plate collectors with an inclination of 32° and 3.5m3 of storage tank is achieved to cover the demand of air conditioning of a 35kW absorption chiller.
إبراهيم محمد علي الطويري (2011)

This paper identifies the most affecting factors that enhance the quality of the decision making process within some Libyan oil and gas companies. Based on the developed questionnaire along with the literature review, the analysis showed that it is a challenge to processing the proper procedure for making decisions. However, most decision makers are found to be focusing on using simple tools for making their decisions, whereas, lacking of an effective communication network during making decisions are considered with a negative impact on making the proper decisions within most surveyed companies. Furthermore, it was found that, the procedures for making decisions within most surveyed companies could be considered as the most crucial for improving the quality of the decision making processes, followed by the used tools and techniques, whereas, communications as a factor influencing the processes of making decisions is found to be at the lowest level throughout the entire decision making processes. arabic 15 English 98
Rajab HOKOMA, Hanan Zawam Aburas(3-2018)

Abstract Glass fiber reinforced plastic (GRP) pipes, are widely used in many of industrial applications, such as oil industries and petrochemicals plants to transport a wide range of different liquids like fresh water, sea water, lubricant oils, acids and caustic etc. This related to their lightness, corrosion resistance, strength durability, high tensile strength, low density, and ease of installation, so that selected as better than traditional metal pipes in such applications. But the internal surfaces of these pipes can be exposed to slurry erosion due to the impact of sand particles mixed with fluids at high velocity leads to create, catastrophic failure, which limits the useful life of pipes and their efficiency. Therefore the erosion is a critical parameter for design, selection and operation of hydraulic transportation system. This thesis has studied experimentally the Slurry erosion wear behavior of GRP pips at various parameters such as impact angles, and velocity of particles. Jet type erosion tester was used as rig and sand used as solid particle mixture with water. The results clearly indicated that the factors contribute to wear of Pipes. The erosion rate or weight loss increased as time, and velocity of solid particles increased, the effect of impact angles shifts from ductile behavior to brittle behavior depending on the value of erosion efficiency. The comparison between predicted and experimental results shows agreement within ±7% for Epoxy and ±8% for Polyester.
خالد عيسي المحجوبي (2013)