Temperature dependence of electrical properties of electrodeposited Ni-based nanowires

The influence of annealing on the microstructure and the electrical properties of cylindrical nickel-based nanowires has been investigated. Nanowires of nickel of nominally 200 nm diameter and of permalloy (Py) of nominally 70 nm were fabricated by electrochemical deposition into nanoporous templates of polycarbonate and anodic alumina, respectively. Characterization was carried out on as-grown nanowires and nanowires heat treated at 650°C. Transmission electron microscopy and diffraction imaging of as-grown and annealed nanowires showed temperature-correlated grain growth of an initially nano-crystalline structure with ≤8 nm (Ni) and ≤20 nm (Py) grains towards coarser poly-crystallinity with grain sizes up to about 160 nm (Ni) and 70 nm (Py), latter being limited by the nanowire width. The electrical conductivity of individual as-grown and annealed Ni nanowires was measured in situ within a scanning electron microscope environment. At low current densities, the conductivity of annealed nanowires was estimated to have risen by a factor of about two over as-grown nanowires. We attribute this increase, at least in part, to the observed grain growth. The annealed nanowire was subsequently subjected to increasing current densities. Above 120 kA mm -2 the nanowire resistance started to rise. At 450 kA mm -2 the nanowire melted and current flow ceased

Spatial distribution of hardpans in the Dosso region of Niger A remote sensing approach

Hardpan A soil layer with physical characteristics that limit root penetration and restrict water movement. Soil crust A transient soil-surface layer, ranging in thickness from a few millimeters to a few centimeters, that is either denser, structurally different or more cemented than the material immediately beneath it, resulting in greater soil strength when dry as measured by penetration resistance or other indices of soil strength

Calibration and validation of reference evapotranspiration models in semi-arid conditions

Reference evapotranspiration (ETo) is an important parameter for climatological, hydrological and agricultural management. The FAO56 Penman-Monteith (FAO56-PM) model is one of the most accurate models. But it needs a detailed climate dataset from weather stations. Therefore, empirical reference evapotranspiration models (ETo) that need a reduced set of climate data can become an alternative approach. In this study, nine different evapotranspiration models were calibrated for the 1978-2000 period and validated based on the period between 2001-2017 with respect to standard FAO56-PM method based on the real climatic data obtained from Aseer metrological department, Saudi Arabia. The ranking of all the evaluated models based on the multi-criteria decision making was done in order to get the best alternative to the FAO56-PM Model. The result showed that Mahringer and Trabert models are the most appropriate with RMSE values of 2.13 mm/day and 2.47 mm/day, respectively and the value of percent error were 77.27% and 89.43%, respectively. Moreover, the values of mean bias error were found to be-2.03 mm/day and-2.35 mm/day, respectively. The calibration and validation of different ETo equations tend to increase their performance. Thus, the validated evapotranspiration model that used less climatic parameters could predict the ETo condition accurately for any region

Li-Pos: A Light Positioning Framework Leveraging OFDM for Visible Light Communication

The design of solid-state lighting is vital, as numerous metrics are involved in their exact positioning, and as it is utilized in various processes, ranging from intelligent buildings to the internet of things (IoT). This work aims to determine the power and delay spread from the light source to the receiver plane. The positions of the light source and receiver were used for power estimation. We focus on analog orthogonal frequency-division multiplexing (OFDM) in visible light communication (VLC) and assess the area under the curve (AUC). The proposed system was designed using modulation techniques (i.e., quadrature amplitude modulation; QAM) for visible light communication (VLC) and pulse-width modulation (PWM) for dimming sources. For the positioning and spreading of brightness, the proof-of-concept was weighted equally over the entire area. Therefore, the receiver plane was analyzed, in order to measure the power of each light-emitting diode (LED) in a given area, using the delayed mean square error (MSE). A framework was applied for the placement of LEDs, using full-width at half-maximum (FWHM) parameters with varying distances. Then, the received power was confirmed. The results show that the AUC using DRMS values for LEDs significantly increased (by 30%) when the number of source LEDs was changed from four to three. These results confirm that our system, associated with the simple linear lateration estimator, can achieve better energy consumption

Unexpected elevated alanine aminotransferase, asparte aminotransferase levels and hepatitis E virus infection among persons who work with pigs in accra, ghana

<p>Abstract</p> <p>Background</p> <p>Several studies have suggested that elevated serum alanine aminotransferase (ALT) and asparte aminotransferase (AST) may be markers of hepatitis E virus (HEV) infection. Thus, individuals with elevated ALT and AST may have ongoing subclinical infection of HEV. We estimated the prevalence of anti-HEV antibodies and serum ALT and AST levels among persons who work with pigs in Accra, Ghana.</p> <p>Results</p> <p>Three hundred and fifty- persons who work with pigs provided blood samples for unlinked anonymous testing for the presence of antibodies to HEV, ALT and AST levels. The median age of participants was 32.85 ± 11.38 years (range 15-70 years). HEV seroprevelance was 34.84%. Anti-HEV IgG was detected in 19.26% while anti-HEV IgM was detected in 15.58% of the persons who tested positive. On multivariate analysis, the independent determinants of HEV infection were, being employed on the farm for less than six months [odds ratio (OR) 8.96; 95% confidence interval (95% CI) 5.43-14.80], having piped water in the household and/or on the farm (OR 13.33; 95% CI 5.23-33.93) and consumption of alcohol (OR 4.91: 95% CI 2.65-9.10). Levels >3× the expected maximum were found for both ALT and AST among individuals who tested positive for anti-HEV IgG (ALT, 210.17 ± 11.64 U/L; AST, 127.18 ± 11.12 U/L) and anti-HEV IgM (ALT, 200.97 ± 10.76 U/L; AST, 120.00 ± 15.96 U/L).</p> <p>Conclusion</p> <p>Consistent with similar studies worldwide, the results of our studies revealed a high prevalence of HEV infection, ALT and AST values in pig handlers.</p

Potential Welfare Benefit of Millets Improvement Research at ICRISAT: Multi country - Economic Surplus model approach, Socioeconomics Discussion Paper Series Number 15

In this paper a multi-regional international trade model using concepts of economic surplus and spillover effects is used to estimate the ex-ante measures of the relative economic benefits (accounting both direct and spillover benefits) to provide evidence for the research managers and policy makers in making judgment for prioritizing production domains for millets research focus and research resource allocation among regions and countries. The empirical results indicate that the highest expected benefits to millet research could be generated when research is focused on production domain -warm tropics dryland, 120-149 days- but the high payoff production domains are different among regions. In Asia, the warm tropics drylands, 120-149 days is the highest payoff production domains with $479.85 M benefits but for WCA and ESA the highest payoff production domains is warm tropics drylands, 90-119 days and warm tropics subhumid, >150 days with expected benefits of$242.42 M and $15.06 M respectively. The contribution of spillover benefits to the total international benefits varies between 45 to 97% depending upon the research focus in different production domains. The analysis also indicates that the potential benefits of millets research could be tripled or even quadrupled by improving the adaptive research capacity and adoption of technology among farmers. The analysis clearly brought out the insights to focus ICRISAT’s millet research to achieve maximum international benefits to generate greater impacts. The distribution of benefits across the regions and countries can be used to support millet research funding decisions

Building local capacities in the operation and management of an integrated solid waste management programme; Experience of Ampara District, Eastern Sri Lanka

Open dumping and burning of wastes in the environmental sensitive areas were common practices in almost all the local authorities in Ampara district. It had become a big threat to public health, the beautiful natural environment and to the local economy. The Local Authorities of the District often faced severe difficulties in the management of solid waste in an environmentally, socially and economically feasible manner. The lack of technical and financial capacities to apply and practice the newly developed waste management guidelines and policies further aggravated this situation.Having identified the gravity  and the importance of this serious environmental issue, the Department of Assistant Commissioner of Local Government of Ampara District, with the financial assistance of the European Union and the technical assistance of the United Nations Office for Project Services (UNOPS), is currently implementing an Integrated Solid Waste Management Programme (ISWMP) in 12 local authorities of the District. This ISWMP is completely being operated with the full coordination of the District Office of the Central Environmental Authority, Ampara. The UNOPS, as part of its technical assistance, has constructed solid waste management facilities such as 7 engineered landfills, one Waste Transfer Station, 4 Recycling Centers, 5 compost yards, well developed collection systems  as well as provided with capability building/training assistance aiming to establish an effective and efficient solid waste management system for the District. These  facilities are now completed,  already in use and operational. With these facilities in place, and with the continued support from UNOPS in providing institutional and capacity building assistance to the LA officers and staff, haphazard dumping and littering of waste in certain areas of the LAs have now been stopped. Thus 45,000 urban households or 58% of the total urban population are benefitted under thisprogramme with a total collection of 137tonnes of wastes per day through this programme. Out of this 137tonnes of waste, 59 tonnes are collected from cluster systems involving five local authorities while the balance from the other non-clustered Local Authorities.The paper will also present the processes and methodologies to improve the landfill practices from the open dumping practices to controlled tipping and then to engineered landfills  among the implementing local authorities. It will also highlight interventions/strategies to ensure sustainability of the operation and their management through the introduction of a User Fee system/Service Charge which is currently being implemented in 04  Local Authorities. This collected User Fee covers about 80% of cost of collection of waste which would otherwise been spent through their normal budget.Key words: Integrated Solid Waste Management, Ampara, haphazard dumping, controlled tipping, engineered landfill

Life cycle assessment of functional materials and devices : opportunities, challenges, and current and future trends

Functional ceramics such as piezoelectrics, thermoelectrics, magnetic materials, ionic conductors, and semiconductors are opening new frontiers that underpin numerous aspects of modern life. This widespread usage comes with a responsibility to understand what impact their mass production has on the environment. Life‐cycle assessment (LCA) is a tool employed for the identification of sustainable materials pathways through the consideration of environmental burdens of materials both during fabrication and as a final product. Although the LCA technique has been widely used for the evaluation of environmental impacts in numerous product supply chains, its application for environmental profiling of functional ceramics is now gaining attention. This paper presents a review of current developments in LCA, including existing and emerging applications with emphasis on the development and fabrication of functional materials and devices (FM&D). Selected published works on LCA of functional ceramics are discussed, highlighting the importance of adopting LCA at the design stage and/or at laboratory stage before expensive investments and resources are committed. Drawing from the extant literature, we show that the integration of environmental and sustainability principles into the overall process of FM&D manufacturing, in a way that anticipates foreseeable harmful consequences while identifying opportunities for improvement, can aid the timely communications of key findings to functional materials developers. This guides the orientation of research, development and deployment, and provides insights toward the prioritization of research activities while potentially averting unintended consequences. It is intended that the review presented will encourage the materials science community to engage with LCA to address important materials design, substitution, and optimization needs

Electrochemical Oxidative Fluorination of an Oxide Perovskite

We report on the electrochemical fluorination of the A-site vacant perovskite ReO3 using high-temperature solid-state cells as well as room-temperature liquid electrolytes. Using galvanostatic oxidation and electrochemical impedance spectroscopy, we find that ReO3 can be oxidized by approximately 0.5 equiv of electrons when in contact with fluoride-rich electrolytes. Results from our density functional theory calculations clearly rule out the most intuitive mechanism for charge compensation, whereby F-ions would simply insert onto the A-site of the perovskite structure. Operando X-ray diffraction, neutron total scattering measurements, X-ray spectroscopy, and solid-state 19F NMR with magic-angle spinning were, therefore, used to explore the mechanism by which fluoride ions react with the ReO3 electrode during oxidation. Taken together, our results indicate that a complex structural transformation occurs following fluorination to stabilize the resulting material. While we find that this process of fluorinating ReO3 appears to be only partially reversible, this work demonstrates a practical electrolyte and cell design that can be used to evaluate the mobility of small anions like fluoride that is robust at room temperature and opens new opportunities for exploring the electrochemical fluorination of many new materials