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Not AvailableSoil and water salinity, waterlogging, and a lack of good quality irrigation water are the principal con-straints affecting the productivity of the coastal areas in the humid tropical region. The present studywas conducted at four sites in the coastal lowlands of the Andaman Islands to assess the impact of apermanent raised bed and furrow (RBF) system on waterlogging and salinity. The RBF system improvedthe drainage of the raised beds, maintained a favorable soil moisture content, harvested rain water to amaximum depth of 120 cm, and prevented the entry of tidal and runoff water into the furrow. Betweenthe years 2009 and 2014, the soil salinity in the raised beds was reduced by 85% from the initial level of10.9 dS m−1during three distinct phases namely, the lag phase, the leaching phase and the equilibriumphase which were recognized based on their rate of reduction of salinity Similarly significant reduc-tions were observed in seasonal variations and in the vertical salinity gradient. Interannual variationsin salinity closely followed the rainfall pattern, particularly during the dry period. The data showedsignificant reduction in the concentration of soluble ions (e.g., Na+, Ca2++ Mg2+, Cl−and SO42−). In addi-tion, over the years the salinity and sodium toxicity in the furrow water decreased and became suitablefor irrigation and fish culture. In contrast, the coastal lowlands adjoining the RBF system experiencedwaterlogging (5–81 cm) and high levels of salinity (3.0–9.1 dS m−1), which closely corresponded with therainfall patterns. Multiple linear regression models were developed to predict the surface soil salinity ofthe RBF system separately for the monsoon (r2= 0.56) and dry seasons (r2= 0.63). Waterlogging and salin-ity peaks in different seasons require a different management strategy, but the RBF system was effectivein addressing this challenge together. The findings from this study would equally apply to other humidtropical coastal regions, provided that considerations are given to the inherent soil properties and thelocal hydrology

Synthesis of cobalt boride nanoparticles using RF thermal plasma

Nanosize cobalt boride particles were synthesized from the vapor phase using a 30 kW–4 MHz radio frequency (RF) thermal plasma. Cobalt and boron powder mixtures used as precursors in different composition and feed rate were evaporated immediately in the high temperature plasma and cobalt boride nanoparticles were produced through the quenching process. The X-ray diffractometry (XRD) patterns of cobalt boride nanoparticles prepared from the feed powder ratio of 1:2 and 1:3 for Co:B showed peaks that are associated with the Co2B and CoB crystal phases of cobalt boride. The XRD analysis revealed that increasing the powder feed rate results in a higher mass fraction and a larger crystalline diameter of cobalt boride nanoparticles. The images obtained by field emission scanning electron microscopy (FE-SEM) revealed that cobalt boride nanoparticles have a spherical morphology. The crystallite size of the particles estimated with XRD was found to be 18–22 nm