Direct Grounding of the transformer neutral point leadms to single line to ground fault current with a high-value, which may reach the value of the three-phase fault current or more. This high fault current causes destruction of fault locations (equipments and operators) and raises the ground voltage that increases the high step and touch voltages, which is dangerous to humans and animals, causes destruction of communications equipment and can be of great danger to the users.

  Those high fault currents can be reduced by inserting resistance to the neutral point of injection feeding transformer.

  According to the historical data, two events of tripping happened in 30kV transformer substation in Tripoli area network, due to high single line to ground fault.

  In this research, the importance and effect of neutral grounding resistance in 30kV system network and its impact in the determining and limiting of the single line to ground fault currents for a network fed by a single or multi sources will be addressed. Also, the characteristic of the neutral grounding resistance installed in 220/30 kV transformer will be determined and discussed.   

  The behavior of single line to ground fault current for the above mentioned tripping events in Tripoli area were measured, and this will be compared to the simulated results of the same cases and discussed.

  The ATP (Alternative Transient Program) and Neplan software programs are used for simulation of such events.

  Finally, the effect of the Temporary Over Voltage (TOV) – which is, also, called Power Frequency Over Voltage on the healthy phases during the single line to ground fault current occurs will be discussed, as well as the effect of the neutral grounding point.

 In this paper, the current model allows to predict the battery runtime and I-V performance. Furthermore, the dynamic features of a battery, such as nonlinear Voc (open circuit voltage), charge and discharge current, and transient response time that they have considered in the proposed model. Moreover, this model neglects the effects of cycle number, temperature, and self-discharge. Depending on the experimental data which has acquired from the previous literatures this model has been verified and found that the model is adequate to reflect the real-time behaviors of the Li-ion battery. An accurate and comprehensive electrical battery model has been proposed and implemented in a MATLAB environment.

This paper deals with an issue of paramount importance in the aviation field because it is concerned with time. This issue is called the “flight delay due to maintenance", which is defined as the measure of the degree of flight maintenance delay. Delay is one of the main performance of any air transport organization.

This paper concerning with the Evaluation of maintenance delay for Afriqiyah Airways as a case study and followed by the methodology of scientific research in collecting and analyzing of the data related to flights, and by calculating the average maintenance delay of the company's aircraft.

The valuable results were obtained from the average flight delay.

According to the company's fleet recorded which obtained from the date of aircraft in year 2019 and it was very low (109%),and this led to continues declining of Afriqiyah Airways, and this indicate there is problem existence which is required to be identified and resolved.

The recommendation for the senior management of the Afriqiyah Airways is to pay more attention to delaying maintenance for flights.

 The Afriqiyah Airways should emphasize the formation of a specialized scientifically qualified team under the name of "flight delay due to maintenance". The tasks of the team will be the planning and monitoring of maintenance delay.

Marine fungi can be found in every marine habitat and are important organisms from ecological and biotechnological perspective. However there is little information on marine fungi in Libya. This study is to reports on fungi species associated to the seagrass Posidonia oceanica(L.) Delil. An endemic seagrass of Mediterranean Sea. Method used is that, the Organisms were isolated from landed plant of the seagrass Posidonia oceanica from different locations along the East costal of Libya. The collected specimens were examined within one week microscopically. Examined samples were then incubated for further 3-4 weeks in sterile glass chambers at room temperature and reexamined. Fungi were identified from fruiting bodies (Ascocarps or Pycnidia) or from superficial conidia in the case of Hyphomycetes. Standard identification keys were used. (12) Fungal taxa have been identified .The identified organisms belong to the classes, Ascomycetes (6) taxa, Hyphomycetes (5) taxa and Coelomycetes (1) taxa. Pleospora pelagicum (Ascomycetes) and Camarosporium roummegueri (Coelomycetes) were not reported, previously from Libya.

The present study reports on Marine fungi associated with the seagrass Cymodocea nodosa (UCRIA) Asher. A widely distributed seagrass in the Mediterranean Sea .The collected specimens were examined under light microscope after incubation period of 4--8 weeks. Of the samples examined ten fungal genera and species have been identified. The identified organisms belong to the classes Hyphomycetes (8 species) and Coelomycetes (2 species) of these, 4 species were reported for the first time in Libya. Brief descriptions of the new records are presented.

This study analyses the mathematical structure of the central pattern generators (CPGs) and their stability analysis. This paper also discusses how to optimizing the CPGs to generate rhythmic patterns for human arm by using the genetic algorithm (GA) with hybrid function. It also focuses on optimizing bidirectional two CPGs in the stable region to generate rhythmic patterns similar to the rhythmic patterns derived from real data without any input or sensory feedback.

The optimal power flow becoming more important because of its capabilities to deal with various situations of power system operation, this problem involves the optimization of system objective functions for power generation operation and control.

  To satisfy the equality and inequality constrains for the highly nonlinear model of power system witch facing problems of voltage variations due to high load changes that leads to voltage collapses, needs to add tools that preventing such conditions to keep system stability, such as FACTS Devices.  

This paper investigating the optimal power flow (OPF) and Economic Dispatch (ED) of the western area of Libyan National Electric Network of (220 &400kv) system, for optimizing power system losses and reducing fuel costs, by using different scenarios to keep the network operating in good condition.

  OPF and (ED) are formulated as an optimization problem for minimizing the total fuel cost and power loss of all committed plants while meeting the network operation constraints. Applying the OPF and ED as base for system analysis with a Unified Power Flow Controller (UPFC) solved most power system problems and maintains system stability even during difficult operation condition.

The present study aimed to investigate physiological and biochemical responses of lentil (Lens culinaris M.) plantlets to salinity stress concomitant with investigating the role of exogenous chitosan (CHT) application strategy (CHT) in ameliorating the deleterious effect of salt stress. In vitro-produced plantlets of lentil were treated with varying levels of NaCl (50, 100 and 150 mM) added to MS solid media and/or a long with CHT (0.1 mg L^-1). lentil shoots and roots of plantlets exposed to NaCl especially (100 and 150 mM levels) exhibited a significant decline in photosynthetic pigments ,carbohydrate fractions. In contrast, lentil shoots and roots sub cultured in salinized MS in vitro and harvested three and ten days later showed increase in proline content, hydrogen peroxide and malondialdehyde. Whereas, addition of CHT (0.1 mg L^-1) to the MS media alone or along with different salt levels especially the lowest salt dose significantly mitigated salt stress deleterious effect by enhancing chlorophylls a and b ,soluble sugars, sucrose , starch and proline accumulation manifesting osmotic adjustment.

Panoramic imaging radiography is a necessary procedure in treatment of patients with dental problems. According to the ALARA (as low as reasonably achievable) principle, dentists must take radiographs of sufficient quality at the lowest possible radiation dose to the patients. The assessment of patient dose on panoramic radiography is difficult because of dynamic nature of the imaging process and the narrow width of the x-ray beam. this study included 40 cases from Albyan dental clinic at Tripoli region. These cases include 23 female and 17 male . Panoramic imaging was performed according to Albyan clinic . Absorbed dose to critical organs ( Thyroid , Eye and lenses) was measured by using OSL (optical simulated luminescence) dosimeters to obtain the absorbed dose in organs during panoramic radiography, based on patient measurement. The overall mean entrance surface dose of female on thyroid, right and left lens of eyes, region in panoramic were 2.457 ,0.427 and 0.452 mSv , respectively. While the the overall dose for male 2.751. 0.362 and 0.421 mSv , respectively. The results show that there are significant difference between doses for male and female this might be attributed to the difference on operating parameters (mAs and Kvp ) during imaging processing which are not controlled by operators. The doses obtained in this study were lower than the documented threshold that could cause significant damage in the various organs, not undermining stochastic effect of radiation. This study will assist in setting Diagnostic Reference Level for panoramic imaging in Libya.

Several new exact solutions of the (3+1)-dimensional Jimbo-Miwa equation and its two extended forms have been successfully obtained by using the Riccati mapping equation method. Although some of the dispersion relations are the same as in our solutions consedered new .