The performance of PV systems is generally affected by the real weather conditions. In the desert climate, dust accumulation is one of the main concerns that may cause a significant deterioration of ...PV efficiency. In the present work, experimental investigations were carried out to understand the dust characteristics and its effect on the electrical performance of PV modules under Sharjah, UAE weather conditions. The morphology of the dust sample indicates that dust particles have different shapes and small sizes (1.61–38.40 μm). The results of the indoor experiments reveal a linear relationship between the dust density and the normalized PV power with a drop of 1.7% per g/m2. Dust accumulation is a function of the tilt angle and it increases by 37.63%, 14.11% and 10.95% with respect to the clean module for the 0°, 25° and 45° tilted modules, respectively. Outdoor experiments showed that the soiling loss increased by 12.7% while the dust density increased by 5.44 g/m2 for a period over 5 months. By comparing the results of indoor and outdoor experiments, it was concluded that the linear relationship is reliable and can be used to predict the soiling loss of PV systems in UAE and similar weathers conditions.
•Dust sample is characterized for its particle size distribution and elemental composition.•PV power decreased linearly by 1.7% per g/m2 in both indoor and outdoor experiments.•Dust density increased by 5.44 g/m2 in a period of over five months.•Dust accumulation reduced the power output by 12.7% under real weather conditions.•Rainfall contributed to improving the PV performance and decreased the dust density.
This study introduced action research to a group of 25 teachers in a K-12 school in Pakistan. The objective was to understand how teachers viewed their identity as teachers and how they perceived ...action research as a possible professional development tool. Data were obtained through three focused group interviews with 12 volunteers from the initial group which was later analyzed through discourse analysis. Findings from data are shared about action research as a viable tool in effective learning and instruction. The teachers shared their apprehensions about action research. Implications for equitable education and research in international contexts have been discussed.
Renewable energy is considered to be sustainable solution to the energy crisis and climate change. The transition to renewable energy needs to be considered on a sectoral basis and one such sector ...that can potentially decarbonized with renewable energy is the telecommunication sector. Several base transceiver stations (BTS) in remote regions have unstable electric supply systems. Diesel generators (DG) are a common solution to energy problems on such telecommunication sites. However, they have high fuel costs on the global market and contribute to high carbon emissions. Hybrid renewable energy systems may provide a stable power output by integrating multiple energy sources, essential for supplying a dependable and uninterrupted power supply in the context of the telecom sector, notably base transceiver stations (BTS). Deploying such a system might also help BTS, which relies mainly on diesel generators with battery storage backup, reduce operational costs and environmental problems. This study presents the framework for large-scale photovoltaic system penetration based on techno-economic analysis (based on actual on ground data with least assumptions) in base transceiver stations (BTS) encapsulating telecom sector spread across various geographical regions. The proposed framework includes a mathematical model complemented with system design in HOMER software tool. The techno-economic aspects of the study were spread across 2, 12 and 263 sites, along with comparison analysis of photovoltaic system installation with and without energy storage devices, respectively. The sites included both on-grid and off-grid sites, which were exposed to high levels of power outages and subjected to reliance on costly and environmentally hazardous diesel generators. Optimization results showed that the photovoltaic system with a diesel generator and battery storage system provide a promising solution to the energy problem, with an average decrease in LCOE of 29%, DG hour’s reduction by 82% with 92% reduction in carbon emission and a reduction in NPC of 34% due to the high availability of solar. The techno-economic analysis indicated that optimized photovoltaic system and storage results in both on–off grid BTS sites with better options, amid low cost of energy and free accessibility of solar. Moreover, the results spread across geographical regions aiming at a reliable and environmentally friendly option that reduces load on utility grid across on-grid BTS sites and substantial overall reduction in diesel usage.
Nanofluid dynamic properties have varied consequences in several contexts, including those of cooling, building environments, heat transfer structures, microwave flow cytometry, energy generation, ...hyperthermia therapies, and related activities. This work presents a numerical examination of the unsteady separated stagnation point flow of
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nanofluid. The study examines the combined impact of buoyancy and heat source effects, as well as mass suction and slip conditions, on the behavior of the system. In this study, we establish a new mathematical model for nanofluids, which we use to derive similarity solutions in the form of a system of ordinary differential equations (ODEs). The bvp4c technique in MATLAB is used to find approximations to the solutions of certain reduced ODEs. A comprehensive analysis has been undertaken to investigate many physical parameters, revealing that the skin friction coefficient exhibits an upward trend with increasing nanoparticle volume percentage and an unsteadiness parameter for opposing flow. The pattern is also evident in the fluid’s heat transfer rate. In addition, the influence of the stagnation and unsteadiness parameters on the heat transfer performance is significant. The incorporation of the melting heat parameter results in a broader variety of temperature profiles, hence leading to a spontaneous decrease in the rate of heat transmission. Furthermore, the paper incorporates a validation process to substantiate the suggested model and reinforce the conclusions.
Domestic violence is the most prevalent form of gender-based violence that threatens the wellbeing and dignity of women. In this paper, we examine whether and how exposure to physical or sexual ...assault by male partners influences women's decision to initiate a new business when they have access to financing. We collected primary data from rural Bangladesh in collaboration with a microfinance institution that provided small collateral-free loans to a group of married women. We conducted a baseline survey before loan disbursement and then conducted a follow-up survey 12 to 15 months later to collect information on loan usage. We find that women who experienced physical or sexual violence by their husband before receiving a loan are less likely to initiate a new business with their loan than those who did not experience such violence. Exposure to domestic violence obstructs the initiation of new businesses through reduced entrepreneurial self-efficacy and increased fear of business failure. The adverse impact of domestic violence is more detrimental for women who recently experienced another potentially traumatic event—an environmental disaster—than for those without such an experience.
•Exposure to domestic violence influences women's initiation of a new venture.•Violence obstructs entrepreneurship through reduced self-efficacy and increased fear of failure.•Experience of environmental disasters magnifies the negative impact of domestic violence.
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-methylguanine-DNA methyltransferase (MGMT) promoter methylation and its subsequent loss of protein expression has been identified to have a variable impact on clinical outcome of glioma patients ...indicated for chemotherapy with alkylating agents (Temozolomide). This study investigated methylation status of MGMT gene along with in situ protein expression in malignant glioma patients of different histological types to evaluate the associated clinical outcome vis-a-vis use of alkylating drugs and radiotherapy. Sixty three cases of glioma were evaluated for MGMT promoter methylation by methylation-specific PCR (MS-PCR) and protein expression by immunostaining (IHC). Methylation status of MGMT and loss of protein expression showed a very high concordant association with better survival and progression free survival (PFS) (p < 0.0001). Multivariate Cox regression analysis showed both MGMT methylation and loss of protein as significant independent prognostic factors in glioma patients with respect to lower Hazard Ratio (HR) for better OS and PFS) p < 0.05. Interestingly concordant MGMT methylation and lack of protein showed better response in TMZ therapy treated patient subgroups with HR of 2.02 and 0.76 (p < 0.05). We found the merits of prognostication of MGMT parameters, methylation as well as loss of its protein as predictive factors for favorable outcome in terms of better survival for TMZ therapy.
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