M(3000)F2 and IRI-2012 model at an equatorial latitude in the African sector

We have used ionosonde data from Ouagadougou (Geo. Lat.12.40 N, Long. 358.50, Magnetic declination -5.1320) to study the morphology of M(3000)F2 and to investigate the performance of IRI-12 during 1991 and 1995, years of high and low solar activities respectively. Results show that M(3000)F2 exhibits diurnal and solar cycle characteristics with no distinctive monthly/seasonal features. The two peaks which characterize the diurnal M(3000)F2 during high solar activity (HSA) are reduced to just one (the sunrise peak) during low solar activity (LSA). The study also shows that IRI-12 gives good representations of the observed values of M(3000)F2 with high correlation coefficient, R ranging between 0.9 and 0.95 during LSA and 0.94 and 0.99 during HSA. The model gives its best performance in the months of April irrespective of the solar activity. It either under-estimates or over-estimates the observed values of M(3000)F2 during other months.

MIMO Detectors: A Comprehensive Performance Analysis

Multiple-input multiple-output (MIMO) systems are increasingly becoming popular due to their ability to multiply data rates without any expansion in the bandwidth. This is critical in this era of high-data rate applications but limited bandwidth. MIMO detectors play an important role in ensuring effective communication in such systems and as such the performance of the following are compared in this paper with respect to symbol error rate (SER) versus signal-to-noise ratio (SNR): maximum likelihood (ML), zero forcing (ZF), minimum mean square error (MMSE) and vertical Bell laboratories layered space time (VBLAST). Results showed that the ML has the best performance as it has the least Symbol Error Rate (SER) for all values of Signal to Noise Ratio (SNR) as it was 91.9% better than MMSE, 99.6% better than VBLAST and 99.8% better than ZF at 20db for a 2x2 antenna configuration., it can also be deduced that the performance increased with increase in number of antenna for all detectors except the V-BLAST detector.

Use of polyethylene terephthalate as an Anti-stripping agent in GLASSPHALT

This study evaluates the use of polyethylene terephthalate (PET) in Glassphalt aimed at increased bonding effect of bitumen, reduced stripping and increased in stability and strength. Control mix were prepared with bitumen content of 5.0, 5.5, 6, 6.5 and 7% to determine the optimum bitumen content (OBC). Optimum glass content (OGC) was obtained from samples prepared with glass content of 5, 10, 15, 20, and 25% replacement by weight of fine aggregates. The OBC and OGC were used prepare samples with PET content of 2, 4, 6, 8, and 10% by weight of the OBC. The optimum PET content had a higher stability value of 5.8kN and higher air void of 3.8% when compared to the control mix. Stripping value tests showed that PET modified glassphalt had 0% stripping after a period of 48 hours. Waste PET of 6.6% in 16% glassphalt is recommended for use as an anti-stripping agent.

Influence of vehicular emissions on metropolitan trees using chlorophyll contents

The study assessed carbon sequestration potential of the identified trees {Gmelina, Mango, Neem, Masquerade, Step and Cassia} along the five selected roadsides in Abeokuta metropolitan. Leaves of the identified trees were plucked, digested in triplicate and analysed for chlorophyll (Ch) A, B and A+B contents using UV-visible spectrophotometer. Obtained data were subjected to descriptive and inferential statistics while correlation analysis for relationship between the analysed leaf Ch contents. Results indicated that leaf chlorophyll contents varied. The ranking of tree to metropolitan vehicular emission along roadsides was Neem < Gmelina < Mango < Masquerade tree. Correlation matrix analysis indicated that production of the Ch contents across the roadsides tree species was not alike and might be due to their specific reactions to vehicular emission. In conclusion, the order of Ch contents might be the tree species potential to withstand vehicular pollutants.

Effects of different steeping methods on the microbial quality of ‘ogi’ produced from Sorghum bicolor (Linn)

In this study, the effects of different steeping methods on the microbial quality of ‘ogi’ produced from Sorghum bicolor (Linn.) grains were carried out. The sorghum grains were divided into four parts; the first part (Sample A) was steeped with cold water at 30+ 2oC for 72 h and washed with water before milling, the second part (Sample B) was steeped with cold water at 30+2oC for 72 h but was not washed before milling, the third part (Sample C) was steeped with hot water at 30+2oC for 24 h and washed before milling, while the fourth part (Sample D) was steeped with hot water at 30+2oC for 24 h and was not washed before milling. The processed raw ‘ogi’ samples were subjected to standard microbiological techniques to enumerate the microorganisms present. The highest bacterial count of 3.5 x 103cfu/ml was observed in sample B, the highest fungal count of 2.5 x 104 sfu/ml was observed in sample B, while sample C yields the lowest bacterial count of 8.0 x 102 cfu/ml and fungal count of 4.0 x102 sfu/ml. Good hygienic conditions during the processing of the ‘ogi’ must also be employed to reduce the chances of microbial contamination.

Antibiotic Resistance Profiling of Salmonella sp. isolated from African Catfish (Clarias gariepinus)

The African catfish (Clarias gariepinus) is an important fresh water fish consumed by a large percentage of the populace globally and it may be contaminated by pathogenic bacteria such as Salmonella sp. In this study, a total of fifteen (15) samples of African catfish were collected from different markets in Lokoja, Nigeria. The Salmonella sp. were isolated from the catfish samples by pre-enrichment in peptone water and subsequent inoculation on selective medium namely brilliant-green agar (BGA), bismuth sulphite agar (BSA) and Salmonella-Shigella agar (SSA). The Salmonella isolates were tested for susceptibility to 10 different commercially available antibiotics using the disc diffusion method. A total of thirty-four Salmonella species was isolated. The percentage occurrence of Salmonella sp. in the catfishes examined was very high (80%). The incidence of Salmonella sp. in the intestine (86.7%) of the catfish was higher than for the gills (66.7%) and the skin (73.3%). Majority of the isolates were resistant to Amoxicillin, Sulfomethoxazole-trimethoprim, Amoxicillin-clavulanic acid and Streptomycin. This study therefore demonstrated the occurrence of Salmonella species in African catfish with some exhibiting antibiotic resistance. Thus, there is a potential risk of transmission of drug resistant Salmonella species to man when contaminated catfish is consumed. The use of antibiotics in fish farming should be regulated so as to decrease antibiotic residues in fish.

Effect of soaking conditions on properties of flour from sweet potato slices

Native flour of sweet potato has limited industrial applications. This study investigated effect of soaking sweet potato root in hot water and citric acid concentrations on flour properties. Sweet potato root was soaked at temperatures of 50oC, 60oC and 70oC for 2 h; citric acid concentrations of 1%, 3% and 5% for 1 h, and combination of best samples in each of the first two modification treatments in 50:50 proportions. Treated root was processed into flour using standard procedures. Proximate, functional and pasting properties of the flours were determined using standard methods. The flour was used as major ingredient in production of baked snacks. Treatments had significant effect on proximate, functional and pasting properties of the flour. Moisture content ranged from 6.5 to 9.7%, protein content 1.6 to 3.0%, ash content 0.1 to 3.15%, fiber content 3.6 to 4.2%, and carbohydrate content 82.1 to 84.7%. Water and oil absorption capacities ranged from 2.2 to 3.0 ml/g and 0.8 g/ml to 1.8 g/ml respectively, swelling power (4.32 to 9.23 g/g) and bulk density (0.77 to 0.95 g/ml). Snack produced with flour gotten from 60oC soaked root for 2 h was best in sensory ratings.

Behavior of under and over-reinforced concrete slender beams at failure

The focus of this paper is to examine the behavior of under and over-reinforced concrete slender beams at failure. The total number of the beams were five, with the provision of the following percentage of tension reinforcements: 1.01% for beam 1 (B1), 1.51% for beam 2 (B2), 2.01% for beam 3 (B3), 2.62% for beam 4 (B4) and 3.01% for beam 5 (B5). The beams were loaded with point loads at the center, with shear span/depth ratio of 3.8. The actual ultimate load of the experimental beam B1 was 141% of the estimated ultimate, while for beams B2, B3, B4 and B5, the actual ultimate loads were between 68% and 87% of the estimated ultimate loads for the beams respectively. The reinforced concrete beams B1, B2 and B3 had the capacity to sustain large deformation under constant loads before their ultimate failure, hence will give warning about the impending failure. For beams B4 and B5, although failed at higher loads had limited rotation capacity, hence will not give warnings about the impending failure. Therefore, 2.01% tension reinforcement is recommended as the maximum to be provided, so that the beam section can behave as a ductile section.

Pollution Assessment of the Physico-Chemical Properties of the Lagos Lagoon

Lagos lagoon has received wastewater discharged from different anthropogenic sources. Therefore, this study determined the water quality and identified its pollution status. Water quality index (WQI), several heavy metal pollution indices as well as single factor and comprehensive pollution indices were applied. The obtained data revealed that physicochemical parameter varied between 24.00±1.41 and 27.00±0.71°C for temperature; 2.50±2.83 and 10.50±0.71‰ for salinity; 3.90±0.99 and 4.60±0.85 mg/l for dissolved oxygen; 7.26±0.25 and 8.38±0.66 for pH; 3.50±0.71 and 10.00±7.07mg/l for BOD. The results also revealed that sulphate, phosphate and nitrate had means of 10.00±10.45mg/l, 0.85±1.04mg/l and 11.11±17.88 mg/l respectively while Pb, Zn, Cu and Hg had means of 0.25±0.49mg/l, 25.49±44.27mg/l, 1.88±2.94mg/l and 0.00±0.00mg/l respectively. SPI classified pH, BOD, Cu and Zn within the ‘medium pollution’ category while nitrate and phosphate indicated heavy pollution of the lagoon. The PI revealed that Cu and Zn had moderate and slight effect on the aquatic environment respectively while Pb and Hg had no effect on the ecosystem. The mean WQI revealed that the lagoon was classified to be good for aquatic biota despite that HEI and Cd revealed that there was high pollution of heavy metals in the lagoon. The CPI described the lagoon as slightly polluted.

Fatty Acid Composition and Sensory Evaluation of African Catfish, Clarias gariepinus Reared under Different Culture Enclosures

This study was carried out to determine the fatty acid composition and sensory quality of Clarias gariepinus from different culture enclosures (plastic, sandcrete tanks and earthen ponds), at the Teaching and Research Farm of Department of Fisheries and Aquaculture Technology, Federal University of Technology, Akure, Ondo State, Nigeria. The comparative work was carried out to find out if habitat could influence the nutrient composition of the fish. Standard procedures were used in the analysis of tissue nutrient. Sensory evaluation study revealed differences in taste and texture indices considered for C. gariepinus reared in plastic, sandcrete tanks and earthen ponds (p<0.05). Fatty acid profiles of C. gariepinus were determined using Gas chromatography-mass spectrometry (GC-MS) method. The percentage of saturated and unsaturated fatty acids was higher (49.99%, 23.17%) in earthen pond cultured C. gariepinus than the plastic and sandcrete tanks. The study revealed that C. gariepinus raised in earthen pond possess fatty acid composition and sensory quality advantages over the plastic and sandcrete tanks. Keywords: Fatty acids, Sensory evaluation, Culture enclosures, Clarias gariepinus