A Possibility to Enhance Rural Electrification with Small Solar Home Systems Using Light Emitting Diodes

This paper presents a study done in Uganda using LED lights instead of the conventional CFLs.In order to make Solar PV technology available to people living in rural areas, there is the need to reduce the initial investment in Solar Home Systems (SHS), without compromising quality and life span. This paper presents a study done in Uganda using LED lights instead of the conventional CFLs. This option makes it possible to use small sealed deep cycle batteries, low Wattage panels and avoids using charge-controller. Ten of these LED-SHS were installed in a community far from the grid. For three months research assistants were in touch with the users to provide awareness, technical support and gauge customer satisfaction. The test was a success. At the end of the period all users decided to purchase the system and another bigger group manifested interest in replacing their paraffin lamps by LED -SHS. Following the evaluation, a number of improvements have been proposed. The next step is to involve a micro-finance institution to avail the initial capital to pay in one go the USD 150 for the system. Future development includes hiring a designer to make the product more marketable and negotiations with Government and NGOs for possible subsidies

The use of single wire earth return (SWER) as a potential solution to reduce the cost of rural electrification in Uganda

I. P. Da Silva; P. Mugisha; P. Simonis; G. R. Turyahikayo - Electrification and energy provision in rural areasThe rural electrification in Uganda is facing an enormous challenge following the ongoing process of privatisation/liberalisation of the power sector. The Electricity Act enacted in November 1999 provides for more power utilities in the generation, transmission and distribution of electricity, ending a more than 40 years of monopoly of Uganda Electricity Board (UEB), a government parastatal. One of the consequences of this Act is that rural electrification pass to be responsibility of the Ministry of Energy and Mineral Development. This ministry issued a document “Rural Electrification, Strategy and Plan”[1] whose overall objective is to increase electricity accessibility in the rural areas from the actual less than 1% to 10% within 10 years. It supposes to electrify 300,000 new rural households. This objective is meant to be achieved using gridextension, mini-grids and photovoltaic solar systems. This present paper considers the possibility of using SWER for grid-extension and mini-grids aiming at reducing costs. Technical and regulatory aspects are presented.The rural electrification in Uganda is facing an enormous challenge following the ongoing process of privatisation/liberalisation of the power sector. The Electricity Act enacted in November 1999 provides for more power utilities in the generation, transmission and distribution of electricity, ending a more than 40 years of monopoly of Uganda Electricity Board (UEB), a government parastatal. One of the consequences of this Act is that rural electrification pass to be responsibility of the Ministry of Energy and Mineral Development. This ministry issued a document “Rural Electrification, Strategy and Plan”[1] whose overall objective is to increase electricity accessibility in the rural areas from the actual less than 1% to 10% within 10 years. It supposes to electrify 300,000 new rural households. This objective is meant to be achieved using gridextension, mini-grids and photovoltaic solar systems. This present paper considers the possibility of using SWER for grid-extension and mini-grids aiming at reducing costs. Technical and regulatory aspects are presented

Use of solar water heaters in industrial processes to reduce furnace oil consumption

The Solar Water Heaters are already a commercially viable technology for Ugandan households and play an ever more meaningful role on the shift to renewable energy on a global dimension. It is still not the case in industrial applications where oil furnace or firewood are the usual sources of energy for heating. This research project aims at exploring the techni-cal and financial viability of the use of solar water heaters in industries to reduce furnace oil consump-tion and carbon dioxide emission.The high costs and environment problems that arise from the non-renewable sources of energy call for the conversion to more sustainable and less hazardous energy supplies such as solar thermal energy. This paper discusses the use of solar water heaters in industries to reduce furnace oil consumption. Not always solar thermal is viable. Technical design and financial analysis are presented.The high costs and environment problems that arise from the non-renewable sources of energy call for the conversion to more sustainable and less hazardous energy supplies such as solar thermal energy. This paper discusses the use of solar water heaters in industries to reduce furnace oil consumption. Not always solar thermal is viable. Technical design and financial analysis are presented

'Swer (single wire earth return) systems user applications – optimising the use of this cost–effective electrification tool with suitable end-user applications' – the Ugandan case

The impact of SWER (Single Wire Earth Return) systems on any rural electrification programThe access to electricity is becoming a major demand in all societies in the developing countries. The declared aim of Uganda’s Ministry of Energy and Mineral Development to increase the access to electricity to 10% of Uganda’s population implies the electrification of 40,000 rural household per year, bringing ‘power to the people’. Access to electricity is directly associated with higher levels of living conditions. Individual households, (rural and urban) when provided with electricity have better conditions of cleanliness, health and self-empowerment. Key institutions in society (private, governmental, non-governmental, parastatal) also require electricity to enhance the effectiveness and efficiency of their operations and programmes. The introduction of SWER (Single Wire Earth Return) technology has significant merits regarding cost effectiveness to supply electricity to remote areas. This is especially the case where a strong backbone reticulation system is in place to supply high load centres (such as mines and larger towns, water pumping installations). Additional rural settlements and low demand settlements with clinics, schools, hostels, small borehole pumping installations can be adequately supplied with SWER (Single Wire Earth Return) technology.The access to electricity is becoming a major demand in all societies in the developing countries. The declared aim of Uganda’s Ministry of Energy and Mineral Development to increase the access to electricity to 10% of Uganda’s population implies the electrification of 40,000 rural household per year, bringing ‘power to the people’. Access to electricity is directly associated with higher levels of living conditions. Individual households, (rural and urban) when provided with electricity have better conditions of cleanliness, health and self-empowerment. Key institutions in society (private, governmental, non-governmental, parastatal) also require electricity to enhance the effectiveness and efficiency of their operations and programmes. The introduction of SWER (Single Wire Earth Return) technology has significant merits regarding cost effectiveness to supply electricity to remote areas. This is especially the case where a strong backbone reticulation system is in place to supply high load centres (such as mines and larger towns, water pumping installations). Additional rural settlements and low demand settlements with clinics, schools, hostels, small borehole pumping installations can be adequately supplied with SWER (Single Wire Earth Return) technology

Effect of the disorder in graphene grain boundaries: A wave packet dynamics study

Chemical vapor deposition (CVD) on Cu foil is one of the most promising methods to produce graphene samples despite of introducing numerous grain boundaries into the perfect graphene lattice. A rich variety of GB structures can be realized experimentally by controlling the parameters in the CVD method. Grain boundaries contain non-hexagonal carbon rings (4, 5, 7, 8 membered rings) and vacancies in various ratios and arrangements. Using wave packet dynamic (WPD) simulations and tight-binding electronic structure calculations, we have studied the effect of the structure of GBs on the transport properties. Three model GBs with increasing disorder were created in the computer: a periodic 5-7 GB, a "serpentine" GB, and a disordered GB containing 4, 8 membered rings and vacancies. It was found that for small energies (E = EF ± 1 eV) the transmission decreases with increasing disorder. Four membered rings and vacancies are identified as the principal scattering centers. Revealing the connection between the properties of GBs and the CVD growth method may open new opportunities in the graphene based nanoelectronics. © 2013 Elsevier B.V. All rights reserved

Electronic transport through ordered and disordered graphene grain boundaries

The evolution of electronic wave packets (WPs) through grain boundaries (GBs) of various structures in graphene was investigated by the numerical solution of the time-dependent Schrödinger equation. WPs were injected from a simulated STM tip placed above one of the grains. Electronic structure of the GBs was calculated by ab-initio and tight-binding methods. Two main factors governing the energy dependence of the transport have been identified: the misorientation angle of the two adjacent graphene grains and the atomic structure of the GB. In case of an ordered GB made of a periodic repetition of pentagon-heptagon pairs, it was found that the transport at high and low energies is mainly determined by the misorientation angle, but the transport around the Fermi energy is correlated with the electronic structure of the GB. A particular line defect with zero misorientation angle Lahiri et al., behaves as a metallic nanowire and shows electron-hole asymmetry for hot electrons or holes. To generate disordered GBs, found experimentally in CVD graphene samples, a Monte-Carlo-like procedure has been developed. Results show a reduced transport for the disordered GBs, primarily attributed to electronic localized states caused by C atoms with only two covalent bonds. © 2013 Elsevier Ltd. All rights reserved

Electronic states of disordered grain boundaries in graphene prepared by chemical vapor deposition

Perturbations of the two dimensional carbon lattice of graphene, such as grain boundaries, have significant influence on the charge transport and mechanical properties of this material. Scanning tunneling microscopy measurements presented here show that localized states near the Dirac point dominate the local density of states of grain boundaries in graphene grown by chemical vapor deposition. Such low energy states are not reproduced by theoretical models which treat the grain boundaries as periodic dislocation-cores composed of pentagonal-heptagonal carbon rings. Using ab initio calculations, we have extended this model to include disorder, by introducing vacancies into a grain boundary consisting of periodic dislocation-cores. Within the framework of this model we were able to reproduce the measured density of states features. We present evidence that grain boundaries in graphene grown on copper incorporate a significant amount of disorder in the form of two-coordinated carbon atoms. © 2013 Elsevier Ltd. All rights reserved

Epinephrine and short-term survival in cardiogenic shock : an individual data meta-analysis of 2583 patients

Correction Volume: 44 Issue: 11 Pages: 2022-2023 DOI: 10.1007/s00134-018-5372-9Catecholamines have been the mainstay of pharmacological treatment of cardiogenic shock (CS). Recently, use of epinephrine has been associated with detrimental outcomes. In the present study we aimed to evaluate the association between epinephrine use and short-term mortality in all-cause CS patients. We performed a meta-analysis of individual data with prespecified inclusion criteria: (1) patients in non-surgical CS treated with inotropes and/or vasopressors and (2) at least 15% of patients treated with epinephrine administrated alone or in association with other inotropes/vasopressors. The primary outcome was short-term mortality. Fourteen published cohorts and two unpublished data sets were included. We studied 2583 patients. Across all cohorts of patients, the incidence of epinephrine use was 37% (17-76%) and short-term mortality rate was 49% (21-69%). A positive correlation was found between percentages of epinephrine use and short-term mortality in the CS cohort. The risk of death was higher in epinephrine-treated CS patients (OR [CI] = 3.3 [2.8-3.9]) compared to patients treated with other drug regimens. Adjusted mortality risk remained striking in epinephrine-treated patients (n = 1227) (adjusted OR = 4.7 [3.4-6.4]). After propensity score matching, two sets of 338 matched patients were identified and epinephrine use remained associated with a strong detrimental impact on short-term mortality (OR = 4.2 [3.0-6.0]). In this very large cohort, epinephrine use for hemodynamic management of CS patients is associated with a threefold increase of risk of death.Peer reviewe