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Impact of global warming on photovoltaic power generation over West Africa
摘要： Many West African countries are plagued with poor electricity. The abundance of solar irradiance over the region makes solar energy an attractive solution to the problem, but there is a dearth of information on how the ongoing solar dimming and global warming may alter the solar energy over the region in the future at various global warming levels. This study investigates the impact of climate change on photovoltaic power generation potential (PVP) over West Africa under four global warming levels (1.5°C; 2.0°C; 2.5°C and 3.0°C) and under the representative concentration pathway 8.5 (RCP 8.5) climate change scenario. Fourteen regional climate model simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX) were analysed for the study. The capability of the simulations to reproduce the PVP and climate variables over West Africa is quantified. The results show that the CORDEX simulation ensemble captures the spatial distribution and the annual cycle of climate variables and PVP over West Africa, though with few biases. The simulation and observation indicate that PVP over West Africa ranges from 8% to 25% and the annual cycle is influenced by the seasonal variation of the monsoon system. The simulation ensemble projects a decrease of PVP over West Africa in the future and indicates that the magnitude of the decrease grows with warming levels. The maximum decrease in PVP projected over any country or zone in the region is less than 3.8% even for a warming level of 3.0°C. Hence, the study suggests that ongoing global warming may have an influence on PVP over West Africa.
关键词： West Africa,Global warming,Global dimming,Solar energy,Paris agreement
更新于2025-09-12 10:27:22
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Environmental evaluation of Waste to Energy plant coupled with concentrated solar energy
摘要： Life Cycle Assessment (LCA) was applied to evaluate the environmental impact of a hybrid energy system based on the integration of a Waste to Energy plant with concentrated solar energy plant. In the Waste to Energy (WtE) section only saturated steam is produced, while the superheating takes place in an external superheater fed by the concentrated solar energy or, when this is not enough, by a natural gas backup boiler. Different couples of pressure and temperature, for the superheated steam (51 bar, 440 °C; 60 bar, 480 °C; 70 bar, 520 °C), different values for the solar multiple (1.5, 2.0 and 2.5) and different values for the thermal storage capacity (6 h, 10 h and 14 h) were considered, leading to 27 possible cases. Construction, operation and end-of-life phases were included in the LCA system boundary. Calculated global warming indicator, in kg of equivalent CO2 per MJ of produced electricity, slightly decreases for increasing steam parameter cases and for increasing storage hour cases, while a more relevant reduction was observed for increasing solar multiple values. The main contribution to global warming derives from the operation phase of the WtE part (67-86% of the operation), while the remaining part (14-33%) is given by the solar section, for which, in turn, the main contribution is the impact deriving from the natural gas combustion in the backup boiler.
关键词： WtE plant,life cycle assessment,global warming,concentrated solar energy
更新于2025-09-12 10:27:22
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Powering Africa Using An Off-Grid, Stand-Alone, Solar Photovoltaic Model
摘要： Over 90 % of Sub-Saharan Africa is without electricity access. The rural areas of the few African countries with access lack electricity. Studies have suggested that solar energy systems hold the key to powering the continent. Although, a vast population currently operate fossil-fuel powered generators to meet their basic electricity needs. The study is designed for a 2-bedroom flat inhabited by an average Africa family. A residential building in Akure, Ondo State, Southern Nigeria has this model installed in a stable and reliable condition. The proposed solar photovoltaic model is composed of solar panels, Direct Current (D.C) cables, charge controller, solar batteries, solar inverter, solar bulbs and instrumentation gadgets. The model is an optimum size solar Photovoltaic installation with a maximum power input of 1,800 W. The maximum allowable load is 1,000 W and a maximum charging D.C voltage of 28.2 V. The solar-powered system is equipped with a set of six (6) 300 Watts monocrystalline solar panels. A commercial maximum power point tracking (MPPT) charge controller was used for this model. Two (2) units of Deep Cycle AGM Solar Batteries connected in series are installed for the solar photovoltaic system. A pure sine wave solar inverter was used in the developed solar PV model to transform D.C electricity available in the batteries to A.C electricity. Themodel is a flexible one which could be scaled up as may be desired or required. The solar photovoltaic model has a very high prospect for powering Africa. The model has ample potentials to fulfil economic, social and environmental objectives which qualifies it as a sustainable energy option to improve the quality of life. The implementation of this form of sustainable energy will open even development of the continent and end the electricity woes of the populace.
关键词： Solar Photovoltaic,Global Warming,Africa,Sustainable Energy,Electricity
更新于2025-09-12 10:27:22
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Solar Cells and Energy Materials || 2. Solar energy
摘要： The society and technology that human beings have built for themselves are strongly dependent on the consumption of energy. However, earth’s energy resources have been consumed for a long time, and we will have to face energy resource problems and find solutions now if we wish to develop a sustainable human society. If we continue to use fossil fuels at the current rate, they will be completely exhausted within the 21st century. Therefore, there is an urgent need to shift towards the use of renewable energies such as solar energy, nuclear fusion, wind power, biomass, and geothermal energy instead of continuing to use fossil fuels. Renewable energy resources are abundant and have a low impact on the natural environment. On the other hand, they provide low energy density and strongly fluctuate depending on the place and time. Therefore, creating a stable supply of energy is difficult given the current state of technology and the social system we live in, and there are many difficulties in practically using these energy resources.
关键词： solar energy,global warming,renewable energy,thermodynamics,fossil fuels
更新于2025-09-11 14:15:04
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On Time Domain Analysis of Photoplethysmogram Signals for Monitoring Heat Stress
摘要： There are a limited number of studies on heat stress dynamics during exercise using the photoplethysmogram (PPG) and its second derivative (APG). However, we investigate the most suitable index from short PPG signal recordings for heat stress assessment. The APG waveform consists of a, b, c and d waves in systole and an e wave in diastole. Our preliminary results indicate that the use of the energy of aa area, derived from PPG signals measured from emergency responders in tropical conditions, is promising in determining the heat stress level using 20-s recordings. After examining 14 time domain features using leave-one-out cross-validation, we found that the aa energy extracted from PPG signals is the most informative feature for classifying heat-stressed subjects, with an overall accuracy of 79%. Moreover, the combination of the aa energy with the traditional heart rate variability index of heat stress (i.e., the square root of the mean of the squares of the successive aa intervals) improved the heat stress detection to an overall accuracy of 83%.
关键词： affordable healthcare,thermal stress,global warming
更新于2025-09-10 09:29:36
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SiO <sub/>2</sub> etch characteristics and environmental impact of Ar/C <sub/>3</sub> F <sub/>6</sub> O chemistry
摘要： Perfluorocarbon gases are commonly used for nanoscale etching in semiconductor processing; however, they have the disadvantages of a long lifetime and inducing global warming effects when released into the atmosphere. In this study, the SiO2 etch characteristics and global warming effects of C3F6O gas chemistry, which has a low global warming potential, were compared with those of C4F8 chemistry, which is commonly used in semiconductor processing. Using Ar/C3F6O, the SiO2 etch rate was higher and the etch selectivity of SiO2 over the amorphous carbon hardmask layer was lower than the etch rate and etch selectivity using Ar/C4F8/O2, with all other etch conditions the same. Furthermore, using Ar/C3F6O exhibited more anisotropic SiO2 etch profiles by suppressing the bowing, narrowing, and necking effects compared to the etch profiles using Ar/C4F8/O2. The global warming effects were evaluated by calculating the million metric ton carbon equivalents (MMTCEs) from the volumetric concentrations of the emitted by-product species and process gases, and the results showed that, in the optimized conditions, Ar/C3F6O exhibited a lower environmental impact with an MMTCE of <24% than that of Ar/C4F8/O2. Therefore, it is suggested that the Ar/C3F6O gas mixture is a potential replacement for Ar/C4F8/O2 because of its lower MMTCE and acceptable SiO2 etch characteristics.
关键词： C4F8 chemistry,C3F6O gas chemistry,SiO2 etch characteristics,semiconductor processing,global warming effects
更新于2025-09-09 09:28:46
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Evaluation of the Level of Transmission of Solar Radiation by Eyeglasses (Spectacles) and its Effects on the Human Eye
摘要： Global atmospheric changes such as depletion of Ozone in the stratosphere and global warming contribute to the average increase of ultraviolet radiation on earth. Protective eyeglasses are normally recommended to safeguard the eyes from the harmful effects of solar radiation. In this paper, twenty (20) pairs of eyeglasses were selected based on systematic random sampling to determine the amount of optical radiation transmission and level of attenuation by eyeglasses, in the wavelength range of 200nm to 900nm using 6405 UV/VIS spectrophotometer. All the eyeglasses were found to transmit a substantial amount of ultraviolet radiation. The transmission of visible light depends on the lens colours. It was discovered that the eyeglasses do not provide complete protection from UV radiation. This shows that the glasses can still pose great danger to human eyes.
关键词： Spectrophotometer,Eyeglasses,Human eye,Percentage transmittance (%T),Optical radiation,Global warming,Depletion of Ozone,Solar radiation,Attenuation
更新于2025-09-04 15:30:14