Occurrence and distribution of dibenzofurans and benzo[b]naphthofurans in the crude oils from the Northern and offshore Niger Delta basin,Nigeria

The occurrence and distributions of dibenzofurans (DBFs) and benzo[b]naphthofurans were investigated in crude oils from Niger Delta, Nigeria, by gas chromatography-mass spectrometry-mass spectrometry. The distribution of DBFs was characterized by the predominance of C₂-dibenzofurans. 4-Methyldibenzofuran was the most abundant among the methyldibenzofurans isomers while dimethyldibenzofuran-2 (DMDBF-2), ethyldibenzofuran-1, DMDBF-3, and DMDBF-6 occurred in higher amounts when compared with other DMDBFs. Among the benzonaphthofurans, the abundance of benzo[b]naphtho[2,1-d]furan was higher than other isomers. The DBFs distributions in the oils were not affected by source facies and depositional environments. However, the DBFs concentrations increased with increasing maturity in oils from ADL and MJO oilfields.     

United Nations advances global environmental awareness

The need to address global environmental concerns on an international basis is discussed. Programs underway are noted. The role of the United Nations (UN) in the International Space Year is examined. Activities planned by the UN are described, and their purpose and funding are discussed     

Processing Effects on Chemical,Functional and Pasting Properties of Cowpea Flour from Different Varieties

Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea.     

Utilization of Microvisco-Amylograph to Study Flour,Dough, and Bread Qualities of Hydrocolloid/Flour Blends

Changes in functionality of wheat flour blended with hydrocolloids (alginate, locust bean gum, guar gum, and xanthan) were investigated. Microvisco-amylograph and flour quality analyses were conducted and showed significant (p < 0.05) differences among samples. Correlation of microvisco-amylograph values with other parameters showed that microvisco-amylograph parameters (final viscosity, setback, breakdown, etc.) showed significant (p < 0.05) correlation with other parameters. Microvisco-amylograph breakdown was significantly (p < 0.05) and positively correlated with dough strength and loaf volume. Microvisco-amylograph end of cooling, final viscosity, setback, and breakdown were identified as valuable for determination of flour, dough, and bread qualities as impacted by addition of hydrocolloids.     

Aggregate demand for electricity in South Africa: An analysis using the bounds testing approach to cointegration

Electricity demand in South Africa has grown at a very rapid rate over the past decade. As part of reform initiatives to enhance long-term sustainability of the country's electricity industry, South Africa's authorities have in recent years sought to develop an electricity pricing framework that is cost reflective and forms the cornerstone of demand management schemes meant to foster changes in consumption behaviour and enhance efficiency in resource use. The effects of any pricing policy on aggregate electricity consumption will depend on a useful understanding of the factors that influence electricity demand, and the magnitude to which electricity demand responds to changes in such factors. In this context, this paper applies the bounds testing approach to cointegration within an autoregressive distributed lag framework to examine the aggregate demand for electricity in South Africa during the period 1960–2007. The results indicate that in the long run, income is the main determinant of electricity demand. With electricity prices having an insignificant effect on aggregate electricity demand, future pricing policies will need to ensure that electricity prices are cost reflective and enhance efficiency of electricity supply and use.     

Effects of Pretreatment on Properties of Gelatin from Perch (Lates Niloticus) Skin

Fish gelatins obtained from perch fish skin pretreated with various solutions containing acetic acid, sodium hydroxide (NaOH) and sodium chloride (NaCl) were successfully characterized for their nanostructure pattern using field emission scanning electron microscopy. Each pretreatment transformed collagen to gelatin with fibril, zigzag cracks, straight rods, and cross-linked rods nanostructure patterns. Pretreatment solutions also affect the gel yield, gel strength, amino acid profile, and functional groups in perch gelatin as analyzed by Fourier transform infrared spectroscopy. Samples pretreated with NaCl, NaOH, and acetic acid solution showed the highest gel yield (22.84%) and gel strength (179.84 g). Fourier transform infrared spectra for perch gelatins also revealed weak C–N amide II and III bond stretches as well as weak C=O bond stretch.     

Nutritional quality of complementary food prepared from unmalted and malted maize fortified with cowpea using extrusion cooking

The nutritional quality of extruded unmalted or malted maize fortified with cowpea as complementary food was assessed based on its proximate analysis, amino acid composition and results from rat feeding with the blends. Results indicated a slight decrease and increase in protein content due to malting and extrusion respectively. The changes in fat, crude fibre and ash content were not significant. The blends were a good source of energy, ranging from 1831 to 2045 kJ per 100 g. Extrusion significantly increased the amino acid content of the blends, while malting had a varied effect on each of the amino acids. There was no significant difference in the protein efficiency ratio (PER), net protein ratio (NPR) and weight gain of rats fed the blends when compared with the control (casein diet). The present study shows that malting improved the nutritional quality of the blends. Rats fed the casein diet had higher values for total digestibility (TD) and net protein utilisation (NPU). There was no significant difference (P > 0.05) in the internal organ weights of rats fed all blends except the protein‐free diet. © 2000 Society of Chemical Industry     

Occurrence of aflatoxins in peanuts, milk, and animal feed in Trinidad

The prevalence of aflatoxin B1 (AFB1) in 186 peanut products (140 peanuts, 32 peanut butter, and 14 nut cakes) from supermarkets, road vendors, and sale outlets, and 40 feed samples from dairy farmers was determined using the radioimmunoassay method (Charm II) test for aflatoxins. The frequency of aflatoxin M1 (AFM1) was also determined in 175 raw milk samples from milk collection centers and 37 pasteurized milk samples obtained from supermarkets and sale outlets. Overall, from a total of 438 samples tested, 18 (4.1%) were positive for aflatoxin comprising 5 (2.2%) of 226 peanut products and feeds positive for AFB1, and 13 (6.1%) of 212 milk samples positive for AFM1. All 186 peanuts and peanut products were negative (0.0%) for AFB1 while 5 (7.4%) of 40 dairy feed samples were positive. Of the 175 raw milk samples tested, 13 (7.4%) were contaminated with AFM1 while all pasteurized milk samples were negative. The detection of AFB1 in feed and AFM1 in milk is of public health importance considering the practice of raw milk consumption by the farmers and their families in the country.     

Free convective flow of heat generating/absorbing fluid between vertical porous plates with periodic heat input

This study investigates the free convective flow of heat generating/absorbing fluid between vertical parallel porous plates due to periodic heating of the porous plates. The analysis is performed by considering fully developed flow and steady-periodic regime. The momentum and energy equations, which arise from the definition of velocity and temperature, are written in dimensionless form. Separating the temperature and velocity fields into steady and periodic parts, the resulting second order differential equations are solved to obtain the expressions for velocity, temperature, skin friction and the rate of heat transfer. The effects of various flow parameters such as the suction/injection (s), heat source/sink (δ), Strouhal (St) and Prandtl (Pr) numbers on the skin friction coefficient, rate of heat transfer, velocity and temperature profiles are discussed with the aid of line graphs and contour maps.