11 research outputs found

    Isolation and Identification of Multidrug-Resistant Raoultella terrigena as a Causative Agent of Urinary Tract Infection in Pregnant Women in the South of Libya

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    Raoutella terrigena is an opportunistic bacteria that rarely cause infections in humans. It is facultative Gram negative, rod shaped, present mostly in water, plants, soil, fish and insects. Two strains of R. terrigena have been isolated during a study searching of the must causative bacteria of urinary tract infection, in pregnant women where it counted about 2% of the total isolates. Susceptibility test has revealed multi drug resistance to about 61.5 % of the used antibiotics. This is the first documented report of such infection in Libya

    Parametric study on the thermal performance and optimal design elements of solar air heater enhanced with jet impingement on a corrugated absorber plate

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    Previous works revealed that cross-corrugated absorber plate design and jet impingement on a flat absorber plate resulted in a significant increase in the performance of a solar air heater (SAH). Involving these two designs into one continuous design to improve the SAH performance remains absent in the literature. This study aimed to evaluate the achieved enhancement on performance parameters of a SAH with jet impingement on a corrugated absorber plate. An energy balance model was developed to compare the performance parameters of the proposed SAH with the other two SAHs. At a clear sky day and a mass flow rate of 0.04 kg/s, the hourly results revealed that the max fluid outlet temperatures for the proposed SAH, jet-to-flat plate SAH, and cross-corrugated plate SAH are 321, 317, and 313 K, respectively; the max absorber plate temperatures are 323.5, 326.5, and 328 K, respectively; the maximum temperature differences between the absorber plate and fluid outlet are ~3, 9, and 15 K, respectively; the max efficiencies are 65.7, 64.8, and 60%, respectively. Statistical t -test results confirmed significant differences between the mean efficiency of the proposed SAH and SAH with jet-to-flat plate. Hence, the proposed design is considered superior in improving the performance parameters of SAH compared to other designs

    Power transmission lines electromagnetic pollution with consideration of soil resistivity

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    The alternating current (AC) total interference of power lines may pose a threat to personnel and equipment in its vicinity. The main objective of this work is to determine the electromagnetic distribution and induced voltages on human body, equipment, and houses due to the AC total interference for different soil resistivities. The electromagnetic field and induced voltages may cause health problems to the human body and put it at risk. Two main approaches were used to compute the electromagnetic and induced voltages, namely the field approach, which is based on electromagnetic field distribution, and the circuit approach, which uses the circuit grounding analysis to compute the conductive interference and then uses the circuit based models to compute the inductive interference. Human body, steel houses and 10-km-long transmission line were modelled. The soil resistivity was varied, and the induced voltages obtained from both approaches were compared. Soil resistivity and soil structure are important parameters that affect the AC interference level. The results show that the touch voltage increases when the distance between electromagnetic source and human body increases. For high soil resistivity, the danger of the touch voltage becomes more prominent compared to that for low soil resistivity. Power system voltage level and soil resistivity are two key factors influencing the induced voltage level

    The role of climatic-design-operational parameters on combined PV/T collector performance: a critical review

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    PV/T technology attracted numerous researchers and professionals during the last decades. There are many review papers in the literature evaluated the R&D aspects of PV/T collectors. In fact, there are abundant of case studies discussed the parameters of climate, design and operational conditions affected the PV/T collector performance. But, a comprehensive compilation of the information of those case studies is still a missing link in the literature. Hence, this paper intended to review thoroughly the information regarding the parameters affecting the PV/T collector performance mainly and PV module performance partially. The parameters are supported with the most available R&D to measure the accurate influence of each parameter on the performance. The outcomes from the study are highlighted in lessons learned section

    Examination of Low Voltage Grid- Connected PV Generation Under Different Penetration Levels

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    The existence of abundant and free solar energy has contributed to the rapid development of PV systems, particularly rooftop installations and solar plants construction at transmission and distribution levels. Nevertheless, high penetration level of PV systems at distribution network level could potentially lead to abnormal operation of network. At steady state, the impacts are experienced on voltage (level, profile, stability and drop), line losses, equipment loading, etc. In this paper, a part of Benghazi distribution network is simulated by NEPLAN software. A real data for load and weather were used to simulate the real condition. The paper studies the impacts by comparing the behavior of the distribution grid without PV installations and with PV systems installed with different penetration levels (0%, 50%, 65% and 75%). The results generally showed that the installation of rooftop PV systems caused improvement in voltage profile, decreasing equipment’s (transformers and lines/feeders) loading and line losses. On the other hand, extensive deployment of PV capacity will cause an increase in equipment’s loading. The high penetration of PV systems will also affect the voltage profile, voltage level, and losses. From the results, the allowable penetration percentage (Hosting capacity) for the simulated network must not exceed 65%

    Potential of the Polyvalent Anti-Staphylococcus Bacteriophage K for Control of Antibiotic-Resistant Staphylococci from Hospitals

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    The increasing prevalence of antibiotic-resistant staphylococci has prompted the need for antibacterial controls other than antibiotics. In this study, a lytic bacteriophage (phage K) was assessed in vitro for its ability to inhibit emerging drug-resistant Staphylococcus aureus strains from hospitals and other species of Staphylococcus isolated from bovine infections. In in vitro inhibitory assays, phage K lysed a range of clinically isolated methicillin-resistant S. aureus (MRSA) strains, S. aureus with heterogeneous vancomycin resistance and vancomycin resistance, and teicoplanin-resistant strains. In these assays, 14 of the MRSA strains were initially only weakly sensitive to this phage. However, propagation of phage K on these less-sensitive strains resulted in all 14 being sensitive to the modified phages. The results enforce the principle that, while certain target bacteria may be relatively insensitive to lytic phage, this can be overcome by obtaining modified phage variants from passage of the phage through the insensitive strains. Model in situ hand wash studies using a phage-enriched wash solution resulted in a 100-fold reduction in staphylococcal numbers on human skin by comparison with numbers remaining after washing in phage-free solution. Infusion of the phage into a nonimmunogenic bismuth-based cream resulted in strong anti-Staphylococcus activity from the cream on plates and in broth
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