This paper presents a detailed design of a photovoltaic (PV) system for use in the rural electrification of remote settlements that are far off from the electricity grid. Since investment in building transmission line...This paper presents a detailed design of a photovoltaic (PV) system for use in the rural electrification of remote settlements that are far off from the electricity grid. Since investment in building transmission lines from the grid to these localities is not viable, a good solution is <span>an</span><span> installation in these areas of standalone photovoltaic systems. The design process comprises the choice and dimensioning of the solar panels, the battery storage, DC-AC inverter, and mini transmission grid to the different homes. The design is for a 15 kW PV system including an economic evaluation and analysis using Hybrid Optimization of Multiple Energy Resources (HOMER) software. Data on the average monthly solar radiation and temperature w</span><span>ere</span><span> obtained from various sources, including, Photovoltaic Geographical Information System (PVGIS) for Africa. From this data the study area receives a monthly average solar insolation of 6.16 kWh/</span><span>m</span><sup><span style="vertical-align:super;">2</span></sup><span>/day with the worst month </span><span>being </span><span>August with 5.22 kWh/</span><span>m</span><sup><span style="vertical-align:super;">2</span></sup><span>/day. The total daily electrical energy consumption is estimated to be about 72.525 kWh. Simulation results using HOMER software shows that the overall capital cost of the PV system components is $122,337, a replacement cost of $12,889 and an operation and maintenance cost of $29,946 over 10years. A financial analysis of the system showed that the design was both viable and sustainable with low maintenance cost</span><span>.</span>展开更多
AIM:To evaluate the changes in fundus parameters in patients with Alzheimer’s type dementia(ATD)using optical coherence tomography angiography(OCTA),to record flash electroretinograms(ERG)using the RETeval system and...AIM:To evaluate the changes in fundus parameters in patients with Alzheimer’s type dementia(ATD)using optical coherence tomography angiography(OCTA),to record flash electroretinograms(ERG)using the RETeval system and to explore changes in retinal function.METHODS:Twenty-nine patients with ATD and 26 age-matched normal subjects were enrolled.All subjects underwent OCTA scans to analyse the superficial retinal vessel parameters in the macular area,including the vessel length density,the vessel perfusion density and the area of foveal avascular zone(FAZ),as well as the choroidal thickness.The differences between the patients with ATD and the normal control group were compared and explored the relevant factors affecting vessel parameters.We also recorded the flash ERGs using the RETeval system and intended to explore changes in retinal function by analysing the ERG image amplitude in patients with ATD.RESULTS:The vessel parameters[Pvessel length density=0.005 and Pvessel perfusion density=0.006]and average choroid thickness(P<0.001)in the macular area of the ATD group was less than the control group.The FAZ area was statistically significantly enlarged in the ATD group(P<0.001).These parameters were correlated with the Mini-Mental State Examination(MMSE)score and the Montreal Cognitive Assessment(MoCA).CONCLUSION:Patients with ATD exhibit decreases in the parameters associated with fundus.In addition,these indicators significantly correlate with the MMSE score and the MoCA score.OCTA may be an adjunct tool with strong potential to track changes in the diagnosis and monitoring the progression of the disease.展开更多
文摘This paper presents a detailed design of a photovoltaic (PV) system for use in the rural electrification of remote settlements that are far off from the electricity grid. Since investment in building transmission lines from the grid to these localities is not viable, a good solution is <span>an</span><span> installation in these areas of standalone photovoltaic systems. The design process comprises the choice and dimensioning of the solar panels, the battery storage, DC-AC inverter, and mini transmission grid to the different homes. The design is for a 15 kW PV system including an economic evaluation and analysis using Hybrid Optimization of Multiple Energy Resources (HOMER) software. Data on the average monthly solar radiation and temperature w</span><span>ere</span><span> obtained from various sources, including, Photovoltaic Geographical Information System (PVGIS) for Africa. From this data the study area receives a monthly average solar insolation of 6.16 kWh/</span><span>m</span><sup><span style="vertical-align:super;">2</span></sup><span>/day with the worst month </span><span>being </span><span>August with 5.22 kWh/</span><span>m</span><sup><span style="vertical-align:super;">2</span></sup><span>/day. The total daily electrical energy consumption is estimated to be about 72.525 kWh. Simulation results using HOMER software shows that the overall capital cost of the PV system components is $122,337, a replacement cost of $12,889 and an operation and maintenance cost of $29,946 over 10years. A financial analysis of the system showed that the design was both viable and sustainable with low maintenance cost</span><span>.</span>
文摘AIM:To evaluate the changes in fundus parameters in patients with Alzheimer’s type dementia(ATD)using optical coherence tomography angiography(OCTA),to record flash electroretinograms(ERG)using the RETeval system and to explore changes in retinal function.METHODS:Twenty-nine patients with ATD and 26 age-matched normal subjects were enrolled.All subjects underwent OCTA scans to analyse the superficial retinal vessel parameters in the macular area,including the vessel length density,the vessel perfusion density and the area of foveal avascular zone(FAZ),as well as the choroidal thickness.The differences between the patients with ATD and the normal control group were compared and explored the relevant factors affecting vessel parameters.We also recorded the flash ERGs using the RETeval system and intended to explore changes in retinal function by analysing the ERG image amplitude in patients with ATD.RESULTS:The vessel parameters[Pvessel length density=0.005 and Pvessel perfusion density=0.006]and average choroid thickness(P<0.001)in the macular area of the ATD group was less than the control group.The FAZ area was statistically significantly enlarged in the ATD group(P<0.001).These parameters were correlated with the Mini-Mental State Examination(MMSE)score and the Montreal Cognitive Assessment(MoCA).CONCLUSION:Patients with ATD exhibit decreases in the parameters associated with fundus.In addition,these indicators significantly correlate with the MMSE score and the MoCA score.OCTA may be an adjunct tool with strong potential to track changes in the diagnosis and monitoring the progression of the disease.
