Dust and impurity accumulation has a significant effect on the efficiency and performance of PV panel output power. It influences the transmittance of solar radiation from the PV panels surface. Scheduling weekly or monthly cleaning periods requires complete knowledge of area's weather and environmental condition. In this study, an experimental-based investigation is conducted aiming for a proper scheduling cleaning periods by comparing the output power efficiency of two identical PV panels, the first being cleaned daily and the other cleaned monthly. Both are exposed to unstable weather condition with Sarayat season in April and May, winter and summer Shamal of Kuwait for one year. The results indicated a significant degradation of PV panel output power in April, May, October and December. A need for frequent weekly water washing is a necessity to maintain the power efficiency loss of 15.07%, 13.74%, 10.685% and 8.742% respectively, and frequent monthly water washing for the remaining months of the year.

Background: The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases. Objective: The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis. Methods: Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-β-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated. Results: Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups. Conclusion: Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.

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Modem fabrication processes offer the microwave circuit designer a wide range of techniques and materials for realizing passive planar components, such as bandpass filters. This paper investigates the effects that the fabrication process has on the performance of microwave planar circuits, so as to provide the circuit designer with useful practical information leading to the optimum choice of materials and processes. In order to compare the technologies, single-layer and multi-layer band-pass filter circuits were fabricated and tested at 250Hz and 2.50Hz, respectively.