239 research outputs found

    Factors Associated with Coverage and Usage of Long-Lasting Insecticidal Nets in Madagascar

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    In October 2007, long-lasting insecticidal nets (LLINs) were distributed in 59 of the 111 districts in Madagascar as part of a nationwide child survival campaign. A community-based cross-sectional survey was conducted six months post-campaign to evaluate net ownership, use and equity. Here, we examined the effects of socioeconomic factors on LLIN ownership and usage in districts with and without net distribution during the campaign. Our data demonstrated that in districts with LLIN distribution, LLIN ownership was similar across all wealth groups in households with at least one child under the age of five years (90.5% versus 88.6%); in districts without net distribution, 57.8% of households in the poorest tertile compared to 90.1% of households in the least poor tertile owned at least one LLIN. In contrast, in LLIN-owning households, both in districts with and without net distribution, higher socio-economic status was not associated with use among children under five years. These findings suggest that socio-economic status contributes to the household net ownership but once a household owns a net, socio-economic status is not associated with net use

    Enhancing the renewable energy payback period of a photovoltaic power generation system by water flow cooling

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    A photovoltaic system which enjoys water flow cooling to enhance the performance is considered, and the impact of water flow rate variation on energy payback period is investigated. The investigation is done by developing a mathematical model to describe the heat transfer and fluid flow. A poly crystalline PV module with the nominal capacity of 150 W that is located in city Tehran, Iran, is chosen as the case study. The results show that by increasing water flow rate, EPBP declines first linearly, from the inlet water flow rate of 0 to 0.015 kg.s-1, and then, EPBP approaches a constant value. When there is no water flow cooling, EPBP is 8.88, while by applying the water flow rate of 0.015 kg.s-1, EPBP reaches 6.26 years. However, only 0.28 further years decrement in EPBP is observed when the inlet water mass flow rate becomes 0.015 kg.s-1. Consequently, an optimum limit for the inlet water mass flow rate could be defined, which is the point the linear trend turns into approaching a constant value. For this case, as indicated, this value is 0.015 kg.s-1

    Virulence determination of Beauveria bassiana isolates on a predatory hemipteran, Andrallus spinidens Fabricius (Hemiptera: Pentatomidae)

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    Virulence of the two isolates of Beauveria bassiana, BB2 and AM-118, were evaluated on adults of a predatory hemipteran, Andrallus spinidens Fabricius by conidial bioassay and enzymatic activities. Results of the bioassay revealed LC50 of 37×104 and 15×103 spore/ml for isolates BB2 and AM-118, respectively. Activities of chitinase, lipase and ALP showed the higher activity in the media inoculated by AM-118 while no statistical differences were observed in activity of ACP. Although no statistical differences were found in general protease and Pr1 activities but activity of Pr2 in AM-118 was significantly higher than that of BB2. Activity of general esterases demonstrated no statistical differences when α- and β-naphtyl acetate were used as substrates but activity of glutathione S-transferase in AM-118 was higher than that of BB2 by using CDNB and DCNB as specific reagents. Results of the current study indicated higher virulence of isolate AM-118 against adults of A. spinidens by lower LC50 value and higher activities of the enzymes involved in pathogenicity. Recruiting of these isolates against C. suppressalis must be considered by their adaptability of A. spinidens. Moreover, AM-118 has been isolated from rice fields of northern Iran, so it may somehow indicate a type of host-microorganism interaction

    Production of Radioactive Nuclides in Inverse Reaction Kinematics

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    Efficient production of short-lived radioactive isotopes in inverse reaction kinematics is an important technique for various applications. It is particularly interesting when the isotope of interest is only a few nucleons away from a stable isotope. In this article production via charge exchange and stripping reactions in combination with a magnetic separator is explored. The relation between the separator transmission efficiency, the production yield, and the choice of beam energy is discussed. The results of some exploratory experiments will be presented.Comment: 10 pages, 4 figures, to be submitted to Nucl. Instr. and Met

    Daylighting, artificial electric lighting, solar heat gain, and space-heating energy performance analyses of electrochromic argon gas-filled smart windows retrofitted to the building

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    The inevitability to reduce CO2 emissions to avoid preventable climate change is widely being yelped. To minimise the impact of rapidly changing climate, this paper presents novel research findings and contributes to developing electrochromic argon gas-filled glazed smart windows retrofitted to the building with IoT based transparency control. In this, the comparative analyses of the daylighting, electrical lighting, solar heat gain, and space-heating load of the building using the dynamic thermal and electric lighting modelling methods based on real weather temperatures are presented. The daylighting analysis results implicate that the building with electrochromic argon gas-filled smart windows reduced 19% of daylight illuminance during summer months compared with the building retrofitted with double air-filled glazed windows daylight factor remains consistent. As such, the solar heat gains analysis results implicate at least 50 % annual solar heat gain reduction predicted in the building with electrochromic argon gas-filled smart windows in comparison to double air-filled windows. This leads to the conclusion of the space-heating energy analysis that implicates the highest contribution to the space heating demand is the solar heat gain caused by double air-filled glazed windows. The results confirm that the LED artificial electric lighting system requires fewer fittings and thus total power load compared to the fluorescent lighting system, throughout the year, to the building with electrochromic argon gas-filled glazed smart windows. The daylight controls are linked to the electrochromic argon gas-filled glazed smart windows, so they only operate when the glazing is tinted, or the daylight level drops below a set level; this will reduce the energy usage and also lower the space heating of the room

    The road to developing economically feasible plans for green, comfortable and energy efficient buildings

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    Owing to the current challenges in energy and environmental crises, improving buildings, as one of the biggest concerns and contributors to these issues, is increasingly receiving attention from the world. Due to a variety of choices and situations for improving buildings, it is important to review the building performance optimization studies to find the proper solution. In this paper, these studies are reviewed by analyzing all the different key parameters involved in the optimization process, including the considered decision variables, objective functions, constraints, and case studies, along with the software programs and optimization algorithms employed. As the core literature, 44 investigations recently published are considered and compared. The current investigation provides sufficient information for all the experts in the building sector, such as architects and mechanical engineers. It is noticed that EnergyPlus and MATLAB have been employed more than other software for building simulation and optimization, respectively. In addition, among the nine different aspects that have been optimized in the literature, energy consumption, thermal comfort, and economic benefits are the first, second, and third most optimized, having shares of 38.6%, 22.7%, and 17%, respectively

    Energy and Exergy Analyses on Seasonal Comparative Evaluation of Water Flow Cooling for Improving the Performance of Monocrystalline PV Module in Hot-Arid Climate

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    Solar irradiation in hot-arid climatic countries results in increased temperatures, which is one of the major factors affecting the power generation efficiency of monocrystalline photovoltaic (PV) systems, posing performance and degradation challenges. In this paper, the efficiency of a water-flow cooling system to increase the output of a monocrystalline PV module with a rated capacity of 80 W is studied from both energy and exergy perspectives. The energy and exergy tests are performed for each season of the year, with and without cooling. The energy and exergy efficiencies, as well as the commodity exergy values, are used to compare the photovoltaic device with and without cooling. The findings are based on the experimental data that were collected in Tehran, Iran as an investigated case study in a country with a hot-arid climate. The findings show that when water-flow cooling is used, the values of the three efficiency metrics change significantly. In various seasons, improvements in regular average energy efficiency vary from 7.3% to 12.4%. Furthermore, the achieved increase in exergy efficiency is in the 13.0% to 19.6% range. Using water flow cooling also results in a 12.1% to 18.4% rise in product exergy

    Ft values of the T = 1/2 mirror beta transitions

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    A complete survey is presented of all half-life and branching-ratio measurements related to the isospin T = 1/2 mirror beta transitions ranging from 3He to 83Mo. No measurements are ignored, although some are rejected for cause. Using the decay energies obtained in the 2003 Mass Evaluation experimental ft values are then determined for the transitions up to 45V. For the first time also all associated theoretical corrections needed to convert these results into "corrected" Ft values, similar to the superallowed 0+ -> 0+ pure Fermi beta transitions, were calculated. Precisions of the resulting values are in most cases between 0.1 % and 0.4 %. These Ft(mirror) values can now be used to extract precise weak interaction information from past and ongoing correlation measurements in the beta decay of the T = 1/2 mirror beta transitions

    Aspects of Cooling at the TRIμ\muP Facility

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    The Triμ\muP facility at KVI is dedicated to provide short lived radioactive isotopes at low kinetic energies to users. It comprised different cooling schemes for a variety of energy ranges, from GeV down to the neV scale. The isotopes are produced using beam of the AGOR cyclotron at KVI. They are separated from the primary beam by a magnetic separator. A crucial part of such a facility is the ability to stop and extract isotopes into a low energy beamline which guides them to the experiment. In particular we are investigating stopping in matter and buffer gases. After the extraction the isotopes can be stored in neutral atoms or ion traps for experiments. Our research includes precision studies of nuclear β\beta-decay through β\beta-ν\nu momentum correlations as well as searches for permanent electric dipole moments in heavy atomic systems like radium. Such experiments offer a large potential for discovering new physics.Comment: COOL05 Workshop, Galena, Il, USA, 18-23. Sept. 2005, 5 pages, 3 figure

    Population abundance of pomegranate aphid, Aphis punicae (Homoptera: Aphididae), predators in Southwest of Iran

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    Pomegranate aphid, Aphis punicae Passarini (Hom., Aphididae) is an important pest of pomegranate in Iran. Predators play critical role in natural control of the pest. In this study, seasonal population dynamics of the aphid predators were investigated during two years (2016/2017) in Ilam province, southwest of Iran. Samplings were bi-weekly performed in an experimental pomegranate orchard. Four insect predators, Coccinella septempunctata L., Oenopia congelobata L. (Col., Coccinellidae), Xanthogramma pedisseguum Haris (Dip., Syrphidae) and Chrysoperla carnea Stephens (Neu., Chryspidae) were identified as predators of A. punicae in Ilam. The natural enemies occurred during March to May in both years. The highest and the lowest densities were belong to X. pedisseguum and O. congelobata, respectively. Results of the study can be used for developing integrated pest management program of A. punicae in pomegranate orchards
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