A low speed, open circuit, laboratory wind tunnel was designed and built to facilitate the testing of airfoils designed for use with straight bladed vertical axis wind turbines. The wind tunnel built was the open-circuit type and was chosen due to the ease of fabrication and low construction costs associated with the build. Wind speed through the tunnel was controlled by a variable speed WEG 3.00 hp motor drive unit with a WEG CFW 08 vector inverter plus motor speed control unit. Calibration tests were performed using a hot-wire anemometer to determine the wind velocity as a function of differential pressure measured using a pressure transducer. The characteristic curve of wind velocity vs inches of water was plotted. The velocity profile for this wind tunnel indicated a turbulent flow regime and there was a good second order polynomial relationship between the measured velocity and differential pressure drop.
Aims: The aim of this study was to investigate the influence of flow-distance on the empirical correlation between biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) of wastewaters from a cluster of industries. Study Design: Wastewater samples were collected at point-sources and at 25, 50, 75 and 100m distances from the point-sources. Place and Duration of Study: Nasco Household Products Ltd. Laboratory, Jos, Nigeria. Sampling was done twice a week for a full seasonal cycle at peak production period (morning and evening). Methodology: The samples pH were adjusted to 7 using 0.5M acid for basic samples and 1M alkali for acidic samples, de-chlorinated using 0.0125M Na2S2O3 and seeded when necessary and then diluted with de-ionized water. The dissolved oxygen (DO) content of the diluted sample was determined before and after incubation for 5 days by azide modified Winkler’s method. The difference, taking into account the dilution, gave the BOD5 of the sample. For COD the sample to be measured was oxidized under reflux by 0.125M potassium dichromate and 2mg of sulphamic acid with silver sulphate as a catalyst and a suppressor of chloride interferences. Organic matter reduced part of the dichromate and the remainder was determined by titration with iron (II) ammonium sulphate using ferrion as indicator. Results: The empirical correlation between COD and BOD5 was generally maintained despite the distance of flow of the wastewater from point-source and contributions of washings from farmlands and other human activities. COD and BOD5 of the wastewaters from different sources highly correlated with correlation coefficients ranging 0.9396-0.9985. Conclusion: The correlation between COD and BOD5 for wastewaters was not affected by flow distance. The correlation equations for the industries may therefore be used to deduce rapid effluent quality from chemical oxygen demand (COD) of sample from any point along the effluent flow.
Aims: Contamination of surface water, sediment and fish samples by heavy metals have been a problem of developing countries as a result of growing rate of industrialization. This study was aimed at determining the level of heavy metal toxicants in water, sediment and fish samples from Nkisa River. The effect of these elemental contaminants and the associated health hazards were examined. Study Design: Unicam 919 Atomic Absorption Spectrophotometer (AAS) was used for the determination of heavy metals in water, sediment and fish samples. Place and Duration of Study: Department of Chemistry, Federal University of Technology, Owerri, Nigeria, between October and December, 2012. Methodology: Water samples were pre-treated by repeated evaporation with analar grade nitric acid (HNO3) and heavy metal contaminant in the water samples were determined using Unicam 919 AAS. The wet sediment samples were ashed at 555ºC. 5 g of dried sediment was weighed into a Teflon crucible and 1 cm3 of (HNO3/HCl 1:3 v/v) and 6 cm3 hydrofluoric acid were added into the crucible. The resulting solution after digestion was collected in volumetric flask containing 2.7 g of boric acid. The digested sample was analyzed using Unicam 919 AAS. The whole fish were dried in an electric oven at 70-80ºC. A homogenized 2 g of the ground fish samples were put in flasks and 10 ml each of concentrated HNO3 and HCl were added. After digestion the samples were analyzed using Unicam 919 AAS. Results: The result of this study revealed that water, sediment and fish samples were contaminated with heavy metals such as Cr, Pb, Cd, Fe, Mn. The study indicates that heavy metal contaminant were observed more in the sediment of the river. The associated health hazards of the metals were examined. Conclusion: This study revealed that Nkisa River is contaminated with heavy metals from crude oil pipeline leakages and vandalization. This study gives an idea to the mechanisms of depletion and possible extinction of fish species in Nkisa River.
An experiment was conducted to evaluate the heavy metals toxicity in vegetables irrigated with wastewater. Different experimental sites were selected from district Sargodha, Pakistan. Samples of wastewater, contaminated soil and vegetables irrigated with wastewater were collected and analyzed. Concentration of heavy metals such as Cadmium (Cd), Copper, (Cu), Chromium (Cr), Zinc, (Zn) and Iron (Fe) were determined from soil, water and vegetables samples irrigated with wastewater and fresh water. Cadmium concentration was present from 0.1 to 0.3 μgg-1, chromium concentration from 0.03 to 0.11 μgg-1, Copper concentration from 0.2 to 0.7 μgg-1, iron concentration was present from 2.6 to 4 μgg-1 and Zinc concentration was present from 0.1 to 0.3 μgg-1 in vegetables irrigated with waste water. Heavy metals concentrations recorded in vegetables were within the safe limit except cadmium as recommended by WHO.
Aims: This work is aimed at assessing the dye and colouring potentials of the extracts from the bark of whistling pine and the root of African peach. It is intended to apply these extracts for textile dyeings, drink and food colourings. Place and Duration of Study: The study was carried out in the Department of Chemistry, Delta State University, Abraka, Nigeria, between October, 2012 and March, 2013. Methodology: The bark of the plant, whistling pine (Casuarina equisetifolia) and the root of African Peach (Nauclea latifolia) were collected, chopped, dried and pulverized. The dye extracts were obtained using ethanol (absolute) as extracting solvent. The crude dye extracts were recrystallized in carbon tetrachloride (CCl4) for purification. The percentage yields, melting points, pH and Rf values, UV/visible absorptions and IR spectra were determined. Textile (cotton) dyeings, wash and light fastness tests, drink (local gin) and food (pap) colourings were performed. Results: Whistling pine bark yielded reddish brown colour while the root of African peach yielded brown colour. They gave respectively 13.67% and 9.26% yield, pH values of 5.93 and 5.67, M.pt. of 194ºC and 210ºC, Rf values of 0.84 and 0.64. The dyeings showed varied colour shades, poor wash and light fastness on cotton fabrics. Conclusion: The two dye plants produced fine colours on textile, food and drink. The poor wash and light fastness of dyed fabrics improved with mordanting.
Aims: To assess the source rock characteristics and the depositional environment through Geochemical studies of sediment samples from the Upper Benue Trough. Place and Duration of Study: Department of Geology, Obafemi Awolowo University, Nigeria and The Activation Laboratory Ltd, Ontario, Canada between February 2011 and March 2012. Methodology: Eighteen samples made up of sand, shale, coaly shale, shaly sand and sandy shale, occurring between the depths of 18.3 m and 2725 m were analysed for thirty-four elements, comprising eight major, twelve trace, and fourteen rare earth elements (REE) using the Inductively Coupled Plasma- Mass Spectrometry technique. Results: The results show that the sediments are compositionally rich in Al2O3 and Fe2O3. The low TiO2values of compared to those of Post-Archean Australian average shale (PAAS) suggest that they were derived from more evolved felsic source rock. The relatively low average Rb/Sr and high Th/U ratios indicate that moderate to more intense weathering occurred in the source rock area. The absolute rare earth elements (REE) concentrations were in the order of coaly shale > shale > sandy shale > shaly sand > sand. Conclusion: The Al2O3/TiO2, Eu/Eu*, Th/Sc, La/Sc, Th/Co, La/Co, and Th/Cr ratios indicate that the sediments were probably derived from felsic source rocks. In addition, the high LREE/HREE ratios and the negative Eu anomaly also support felsic source rocks for the sediments whilst the very low V/Cr ratios indicate that these sediments were deposited under anoxic environment, consistent with the series of horst and graben structural framework model of the Benue Trough.
Good quality single crystals of Bisthiourea Potassium Chloride (BPC) were grown by the slow evaporation technique. The crystal system and lattice parameters were found using single crystal X-ray diffraction. The mechanical behaviour was analysed using the Vicker’s microhardness test. The microhardness studies reveal that the hardness of the grown crystal increases with an increase in the load. The Kurtz powder test confirms that the SHG efficiency of Bisthiourea Potassium Chloride is higher than that of KDP. The dielectric studies were carried out on the grown crystals to study the dielectric behaviour. Photoconductivity measurements carried out on the grown crystal reveals the negative photoconducting nature of the crystals.
The thermodynamic and kinetic properties of disazo dyes on polyester fibre and polyamide (nylon) fibre were investigated. The disazo dyes showed high affinity values on the two substrates under study. Some of the affinity values obtained on polyester fabric are -10.25, -12.10, -9.80, -10.35, -14.15 Kj.mol-1 at 363K and those obtained from nylon fabric are -10.03, -10.16, -10.26, -10.04, -10.3Kj.mol-1 at 343K for dyes I-V respectively. However, the affinity values of the dyes were slightly higher on polyester fibre than on nylon 6 fibre. It was also found that the enthalpy of dyeing, and entropy of dyeing values were slightly higher on polyester fibre than on the nylon 6 fibre. The enthalpy of dyeing values obtained on polyester fabric for dyes I-V are -838, -174.7, -15.9, -129.1, -741.8 Kj.mol-1 and those obtained on nylon 6 fabric for the same set of dyes are -223.4, -50.4, -65.9, -62.9, -88.0, Kj.mol-1. The entropy values obtained are -203, -448, -100, -53, -317, -177 Jmol-1k-1 at 363k on polyester fabric and -613, -114, -158, -149, -221 Jmol-1k-1 at 343K on nylon 6 fibre. The activation energy of diffusion results showed that there was high barrier to the mobility of dye molecules within the nylon polymer matrix due to steric effects and hydrogen bond formation between some functional groups of the dyes and the nylon polymer. The results of this study indicated that the dye-fibre interactions are thermodynamically allowed, which described the suitability of these practical dye applications on the synthetic fibres.
Aims: To assess the safe level of cyanide in environment and occupational related activities. Methodology: Systematic literature search of the related articles were carried out using the following databases: PubMed, Science Direct, Scopus, Cochrane Library, Science Citation Index Expanded, CINAHL and Ovid. Results were screened for duplicates and assessed for eligibility. Relevant data were extracted and assessment was conducted based on adverse events associated with cyanide exposure in the ambient air. Results: A total of 8 related studies and 1 unpublished study from US EPA were identified for this review. Only 7 studies mentioned the hazardous level of cyanide with the symptoms in different occupational activity. The hazardous level varies from the lowest of 30µg/m3 to 17 mg/m3. Conclusion: There is no adverse effects of exposure to the low concentrations of cyanide that are generally present in the general environment (<1 µg/m3 in ambient air). However, exposure of HCN at a concentration of >1,000 µg/m3 in ambient air for at least 5 years may show symptoms of toxicity and >7,000 µg/m3 may show signs of thyroid enlargement. As for at least 8.5 months or 24-hour in a confined area of 27m3 at a concentration of > 17,000 µg/m3 or >8,000 µg/m3 respectively may lead to death.
Natural and Human activities have overtime caused significant shift in the climate state creating climate change. The change in climate state affects all aspects of human life causing mass migration and great loss of human life. It is believed that agriculture is the most susceptible sector to climate change thus becoming the major force challenging the livelihood of farmers. Therefore, in response to these forces, farm households have developed strategies to cope with the aftermath of climate change induced shocks. The paper highlights some of these strategies among farmers in different locations. It was noted that the coping mechanisms adopted by farmers suggest that actions changes with different situations. Furthermore, it was noted that the sustainability of most of the coping strategies is questionable due to over dependence on the use of natural resources. It was thus suggested that for greater sustainability of the strategies, there is an urgent need to find sustainable livelihood strategies of life. This would only be possible through materialization of existing policies and programmes allocation of resources and building capacity of farm households.