Acta Chemica Malaysia

The goal of this study is to produce cellulose acetate (CA) hollow-fine-fibre membranes with good water flux performance in the 95 – 96% salt retention range for brackish water desalination. A dry-wet spinning technique was used for the preparation of the hollow-fine-fibre membranes. Hollow-fine fibres were spun using CA dissolved in a suitable solvent and non-solvent mixture comprising acetone and formamide. The effects of the dope composition and spinning parameters such as solvent to non-solvent ratio, bore fluid ratio, take-up speed, dope extrusion rate and heat treatment on the membrane morphology and performance were investigated. The elimination of macrovoids from the morphology of hollow-fine-fibre membranes was achieved in two ways. Firstly, increasing the formamide ratio in the polymer solution and secondly, decreasing the water activity in the bore fluid by adding a solvent (acetone) to water. The mechanical strength of the fibres increased with increasing take-up speeds. This could be attributed to the higher orientation caused by higher take-up speeds. CA hollow-fine-fibre membrane showed good salt retention at an annealing temperature of 86 °C and annealing period of two subsequent times. The developed hollow-fine-fibre membranes showed a good brackish water desalination performance within brackish water operating conditions.

The study examined the influence of the two most prominent exotic species in Abakaliki, southeast, Nigeria and the nutrient accumulation on the soils. The plantations species were Gmelina arborea (Gmelina) established in 1988 and Gliricidia sepium established in the same year. The treatments were: Gmelina Plantation Area (GmPA), Gmelina Free Area GmFA, Gliricidia Plantation Area (GlPA), Gliricidia Free Area GlFA. The experiment was established as a Randomized Complete Block Design (RCBD) with four (4) treatments replicated six (6) times. Ground-truthing survey was carried out using a Geographical Positioning System (GPS) and the point data were keyed in into arc GIS software to delineate the study area. The Gmelina and Gliricidia plantation areas and their respective free areas were mapped into 6 plots, and on each plot, sampling points were randomly established, soil samples were taken using soil auger within 0-20cm soil depth. The overall results of exchangeable bases of the soil indicates that calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), base saturation (BS), exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) differs significantly (P<0.05). However, potassium (K) and sodium (Na) did not differ significantly (P>0.05) from the influence of Gmelina and Gliricidia plantations. Our study further revealed that influence of tree plantation on physical properties showed significant difference (P<0.05) on sand, silt, clay, bulk density and gravimetric moisture content (GMC) except for total porosity which did not differ significantly (P>0.05). Tree plantation and biodiversity conservation ensure sustainable management of natural forest resources. Participation of NGOs and private individuals in plantation development could also be enhanced through the organized taungya farming system and other forms of tree planting like agroforestry system for improved soil conservation and restoration of degraded lands.

An instrument used to detect, and measure radiation dose is called radiation dosimeter. However, it should be reasonably sensitive to irradiation exposure, chemical transformation yield (expressed as G-value) must be sufficiently high, adequate reproducibility, and having stability of chemical solution before and after irradiation is called ideal dosimeter. A dosimeter meeting all these basic requirements is referred as “Fricke dosimeter” proposed a chemical dosimeter based on oxidation of ferrous ions in acidic aerated medium. It had maximum stability and reproducibility and most widely accepted as a standard in measurement of radiation dose. The range of Fricke dosimeter at 304 nm is 4 to 40 K rad. In this research work, absorbance efficiency and change in conductance of Fricke dosimeter has been estimated when we change the concentration of salt. Cesium CS-137 source has been used as gamma radiation source. The change in absorbance and electrical Conductivity verses time was measured individually.