Impact of hydropower dam development on agriculturally based livelihoods of resettled communities: a case study of Duong Hoa Commune in central Vietnam

Dam development is widespread in central Vietnam. Interviews were conducted with households that had been resettled and those that had not to determine the type of agricultural livelihoods that were re-established nine years after resettlement due to the Ta Trach reservoir project. Results showed that resettled households, despite having more forest land, were economically worse off compared with households that were not moved. This discrepancy between households was attributed to less arable land allocated to resettled households. The provision of good-quality land, able to grow crops and food trees, was essential if households were to re-establish a comparable agriculturally based livelihood.     

Degradation of reactive dyes by supercritical water oxidation in a batch reactor

The supercritical water oxidation of three reactive dyes in a batch reactor was studied with varying levels of hydrogen peroxide oxidant. The decolorisation of each dye was measured by absorbance spectrophotometry and quantitatively determined from calibration graphs for each of the three dyes. At the lowest excess oxidant concentration (zero excess), the extent of chromogen destruction was nominally lower for the red dye than for the blue and black dyes.     

An evaluation of surveillance of malaria at primary health care level in Kenya

As less than twenty five per cent of persons suffering from malaria seek formal treatment in most of sub-Saharan Africa, Facility-based morbidity statistics are inadequate for monitoring malaria control programmes. This explorative study assessed whether a health centre equipped with a microscope and trained personnel could monitor malaria transmission within its catchment area. The study was conducted at Chemase Health Centre in Nandi District in Kenya, an area holoendemic for malaria with Anopheles gambiae as the main vector and Plasmodium falciparum as the commonest cause of malaria. From first August to 31 October 1991, first seven children under five years of age on each working day accompanied by their mothers to the maternal and child health clinic were studied. A general examination was performed by a Registered Clinical Officer (Medical Assistant) and thin and thick blood smears made, stained with Giemsa stain and examined for malaria parasites by a Medical Laboratory Technologist. Mothers were interviewed by enrolled community nurses on antimalarial measures they were using in their homes. Four hundred and fifty five children mostly under five years of age, consisting of 48.1% males and 51.9% females, were studied. Malaria parasites were present in 209 (45.9%) blood smears of the children. The percentage of blood smears positive for malaria parasites was high in children below 36 months of age. There was a tendency for low percentage of blood smears positive for malaria in children whose mothers reported using mosquito nets or insecticide sprays. The study did not interrupt the routine of the health centre. Periodic monitoring of new malaria illnesses. and percentage of blood smears positive for malaria parasites in children aged 0 to 35 months should be introduced into health centre practice in Kenya. This catchment area approach could be used to monitor malaria control programmes as well as predicting malaria epidemics.     

Characterization of solution processed,p-doped films using hole-only devices and organic field-effect transistors

We report a solution processed, p-doped film consisting of the organic materials 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (MTDATA) as the electron donor and 2-(3-(adamantan-1-yl)propyl)-3,5,6-trifluorotetracyanoquinodimethane (F3TCNQ-Adl) as the electron acceptor. UV–vis–NIR absorption spectra identified the presence of a charge transfer complex between the donor and acceptor in the doped films. Field-effect transistors were used to characterize charge transport properties of the films, yielding mobility values. Upon doping, mobility increased and then slightly decreased while carrier concentration increased by two orders of magnitude, which in tandem leads to conductivity increasing from 4 × 10^?10 S/cm when undoped to 2 × 10^?7 S/cm at 30 mol% F3TCNQ-Adl. The hole density was calculated based on mobility values extracted from OFET data and conductivity values extracted from bulk I–V data for the MTDATA: x mol% F3TCNQ-Sdl films. These films were then shown to function as the hole injection/hole transport layer in a phosphorescent blue OLED.     

POSS/PA66纳米复合纤维的制备及性能研究

以间氯过氧苯甲酸与八乙烯基笼形倍半硅氧烷（POSS）反应制得的八乙烯基POSS环氧化产物为原料,采用熔融纺丝工艺制备POSS/PA66纳米复合纤维,借助FTIR、TG、FE-SEM和DSC测试方法对八乙烯基POSS环氧化产物和POSS/PA66纳米复合纤维进行表征。结果表明：将间氯过氧苯甲酸与八乙烯基POSS进行反应,可以使部分乙烯基团发生环氧化反应,生成的八乙烯基POSS环氧化产物具有良好的耐热性能。采用熔融纺丝工艺制备的POSS/PA66纳米复合纤维,POSS均匀分散在复合纤维中,纤维的热性能如熔融温度和起始分解温度都有所提高,同时纤维的力学性能也得到改善。     

Failure Mechanisms of Stretchable Perovskite Light-Emitting Devices under Monotonic and Cyclic Deformations

This paper presents the results of experimental and analytical studies of the failure mechanisms of stretchable perovskite light-emitting devices (PeLEDs). The multilayered PeLED structures consist of an anodic layer of poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS), an emissive layer of methylammonium lead bromide (MAPbBr₃), and a eutectic gallium–indium (EGaIn) cathodic layer, which are deposited onto treated polydimethylsiloxane substrates. The intrinsically nonstretchable MAPbBr₃ and PEDOT:PSS are modified with poly(ethylene oxide). The failure mechanisms of the layered stretchable PeLED structures are then investigated under monotonic and cyclic deformations. The optical and scanning electron microscopy images show the deflection and propagation of cracks and wrinkles under applied strains. Cracking of perovskite crystal and debonding of films are also observed with increased cyclic deformation. The effects of the failure mechanisms on the optoelectronic properties of the devices are then studied. The in situ measured transmittance of the PEDOT:PSS (≈75%) reduces with increasing uniaxial strain, and then is increased close to its initial value when the strain is released. The turn-on voltage of the device increases with increasing number of cycles between 50 and 1000 cycles at 20% strain level. The fatigue lifetimes of the PeLED structures are used to explain the design of stretchable perovskite devices.     

Electrochemically Induced High Capacity Displacement Reaction of PEO/MoS2/Graphene Nanocomposites with Lithium

Nanocomposites comprised of poly(ethylene oxide), molybdenum disulfide, and graphene were prepared by the hydrolysis of lithiated molybdenum disulfide in an aqueous solution of PEO and graphene. Structural analysis by XRD shows the nanocomposites are disordered with an expansion of ～6 Å in the interlayer spacing. During the first discharge, the nanocomposites electrochemically dissociates irreversibly into Li₂S and Mo and are able to continously cycle as Li₂S +Mo/Li_x ? S + Mo + Li_x+2 as shown by XRD of the discharged electrodes at different depth of discharge (DOD), cyclic voltammetry (CV), and high resolution TEM. A significant increase of the reversible capacity is found in as‐prepared MoS₂/PEO/graphene composite. The results suggest a new electro‐interaction between lithium and molybdenum metal that only occurs in the nanoregime and is enhanced by PEO. The addition of 2 wt% of graphene to the nanocomposites greatly increases the rate capability with rates as high as 10000mA g^?1 yielding > 250mAh g^?1 and recovering to > 600 mAhr g^?1 at 50mA g^?1.     

Adaptation of the Natural Resources Conservation Service (NRCS) curve number (CN) model in estimating direct run‐off from humid tropical forest catchments

Suitability of the Natural Resources Conservation Service (NRCS) curve number (CN) model of run‐off prediction was evaluated on three humid tropical forested catchments in Kimakia, Kenya. The catchments were dominated by Pinus patula (catchment A), Arundinaria alpina (catchment C) and Pennisetum clandestinum (catchment M). The study used discharge and rainfall data collected between 1958 and 1986. Seventy‐three (73) isolated storms were graphically separated into baseflow, interflow and surface run‐off. Forest cover types significantly improved catchments characteristics that influence baseflow and interflow generation in catchment C but not those that influence surface run‐off production. In its original form, the NRCS CN model resulted in direct run‐off estimates that deviated from observed ones by between 43.8% and 55.3%. These discrepancies were minimized through modification of the β and CN parameters. CN generated empirically using storm rainfall predicted the direct run‐off satisfactorily. Therefore, the modified NRCS CN model adequately estimates direct run‐off from humid tropical forested catchments.     

The gypsum reduction process and its validation using the Mintek Pyrosim model

Waste gypsum is produced as a by-product from the fertilizer, mining industries, and acid mine water neutralization using calcium carbonate and/or lime and desalination processes using reverse osmosis and ion-exchange processes, resulting in environmental and storage problems. The purpose of the study was to establish optimum operating conditions for the recovery of valuable products, e.g., sulfur and precipitated calcium carbonate, from waste gypsum, hence, offer an attractive solution to the gypsum waste problem. The paper presents results on thermal studies of waste gypsum in a tube furnace and its validation using the Mintek Pyrosim model. Gypsum was homogeneously mixed with coal and the reduction experiments conducted. The following findings were made: (i) reduction of waste gypsum is an endothermic reaction since, ΔH values were greater than 0 (ΔH?>?0) when the reduction temperature was increased from 25 to 1200°C, (ii) energy requirement is dependent on temperature and gypsum to coal ratio. Gypsum to calcium sulfide conversion of 83.5 and 83.8% was obtained at the optimum temperature range of 1100–1200°C and gypsum to calcium sulfide conversion of 85.4% was obtained at the optimum coal to gypsum mole ratio of 2.1:1, (iii) excess coal gave a lower conversion, and (iv) the predicted data using Mintek Pyrosim were found to be similar to the experimental data.