Emission of pollutants from wood waste incineration at sawmills in Abeokuta metropolis,Nigeria

This paper reports an assessment of the effects of wood waste burning on air quality and the perceived human health in an urban setting. The concentrations of particulates and selected gases were monitored within the vicinity of sawmills in Abeokuta metropolis. The levels of CO, CO₂, SO₂, NO_x, NO₂, H₂S, CH₄ and particulates at distances from sawmill dumps were measured using portable samplers. Additionally, information on sawmill operations and health problems encountered by the exposed population were collected from a community survey. From the data analyses, between 60 and 100% of wood waste generated by sawmills were burned openly, leading to pollutants emission. The mean concentrations of PM_0.3–0.5 (32 523–40 284 μg/m³), NO₂ (1.0 ppm), SO₂ (3.3 ppm), CO (759 ppm) and CO₂ (4.9%) were higher than the permissible limits at 0–15 m from the dump sites. Almost all sampled parameters showed positive association (R = 0.90–0.98; p < 0.05) at sample sites. Moreover, distance of sites to the dumps explained 51–93% of the variation in parameters levels. Both respiratory and dermal diseases were frequently experienced by the exposed population. Strict land-use zoning, pollution abatement measures, environmental quality monitoring and waste-to-energy interventions are urgently required in the study area.     

Wind characteristics and energy potential assessment in Akure,South West Nigeria: econometrics and policy implications

This paper analysed 11 years of daily mean wind-speed data, measured at Akure, Ondo State, Nigeria, using Weibull and Rayleigh distribution functions. While both distributions showed good agreements in extreme-value estimation patterns, investigation of their wind-speed characteristics modelling criteria, using goodness-of-fit statistics, revealed that the wind data followed the Weibull more than Rayleigh. Monthly wind-speed of Akure city ranged from 1.41 to 4.24 m/s by the Weibull fittings and from 1.40 to 4.16 m/s by the Rayleigh fittings. Overall results, of 2.71 m/s (Weibull) or 2.70 m/s (Rayleigh) mean wind-speed and 18.51 W/m² (Weibull) or 22.26 W/m² (Rayleigh) mean power density, indicated Akure a low wind-speed site, requiring low wind-speed turbine for generating wind energy. Econometric analyses of power output simulations using such turbine system resulted in affordable wind energy cost. These bear policy implications for sustainable wind energy usage in this and similar regions of the world.     

Fluid flow phenomena in the electromagnetic stirring of continuous casting systems,part 1: the behaviour of a cylindrically shaped laboratory scale installation

A model is developed to calculate the flow field produced by electromagnetic stirring generated by a rotating magnetic field. This study has considerable importance due to its applicability to continuous casting systems. Three cases are considered, the first, in which steady continuous stirring is studied, and the numerical results are found to agree well with the experimental observations by other workers. In the second case, alternating stirring is examined, and the critical role of switching frequencies is discussed. Finally, a preliminary allowance is made for free surface deformation for the continuous stirring situation. The effective viscosity is deduced from the transport equations for K, the turbulence kinetic energy, and for ?, the rate of viscous dissipation. The transport equation for K is modified to account for turbulence enhancement due to electromagnetic effects.     

Volatile constituents of roasted tigernut oil (Cyperus esculentus L.)

BACKGROUND: Volatile compounds play a key role in determining the sensory appreciation of vegetable oils. In this study a systematic evaluation of odorants responsible for the characteristic flavour of roasted tigernut oil was carried out. RESULTS: A total of 75 odour‐active volatiles were identified. From these, 13 aroma compounds showing high flavour dilution factors in the range of 16 to 128 were quantified by their odour activity values (OAVs). On the basis of high OAVs in oil, the following aroma compounds [vanillin (chocolate, sweet vanilla), 5‐ethylfurfural (caramel, spicy), 2,3‐dihydro‐3,5‐dihydroxy‐6‐methyl‐4H‐pyran‐4‐one (caramel), phenyl acetaldehyde (honey‐like), ethanone, 1‐(4‐hydroxy‐3‐methoxyphenyl) (faint vanilla)] were elucidated as important contributors to the overall chocolate, sweet vanilla, butterscotch aroma of the oil. CONCLUSION: Odorants with high concentrations in the roasted tigernut oil such as 5‐hydroxymethylfurfural, ethyl hexadecanoate, n‐propyl‐9,12‐octadecadienoate gave relatively low OAVs, so their contributions to the overall orthonasal aroma impression of roasted tigernut oil can be assumed to be low. © 2012 Society of Chemical Industry     

Synthesis of Bisindolylmethanes and Their Cytotoxicity Properties

Polymer supported dichlorophosphate (PEG-OPOCl₂) is an efficient green catalyst for the electrophilic substitution reaction of indole with aromatic aldehydes, in neat condition, to afford an excellent yield of bis(indolyl) methanes with short reaction time, at room temperature. The synthesized compounds and their anti-cancer activity are evaluated.     

Fluid flow and tracer dispersion in shallow tundishes

A mathematical model is developed to describe fluid flow and tracer dispersion in shallow tundishes. Two tundish designs are considered, namely one with a point inlet and a point outlet, and another with a point inlet and a slot outlet. Each of these designs is investigated, both in the absence and presence of flow control devices, the latter consisting of either conventional use of dams and weirs, or a magnetic field imposed perpendicularly to the main flow direction.     

Quality assessment of laminated fillet blocks from blue whiting (Micromesistius poutassou)

Laminated fillet blocks made from blue whiting (Micromesistius poutassou) caught in February and April were assessed for quality. The total protein nitrogen value in February-caught fish was greater than the April-caught fish. The bone content, water content and pH values were consistently lower in the February fish than the April fish. Measurement of the acceptability of deep fried, breaded fingers made from the fish and compared with cod fingers produced from fish caught at the same time of year showed a consistent difference between the cod and blue whiting. In addition, the fish fingers from fish caught in February scored consistently higher than those caught in April. The implications of the findings are discussed.     

The role of gas plumes in agitation and mass transfer in metallurgical systems

A general three-dimensional model is developed for the multi-phase flow resulting from the agitation and mixing of metallurgical systems with gas plumes. This model consists of transport equations for the variables of each phase which are then coupled through interaction parameters. The model is applied to three different systems namely, gas-stirred ladles, emulsification of slag-metal systems and mixing in shallow metal baths with multiple gas jets.