Corrosion of Aluminum Alloy Metal Matrix Composites in Neutral Chloride Solutions

The electrochemical behavior of UNS A0332.00S, UNS A0332.20S, UNS A0359.00S, and UNS A0359.20S aluminum alloys were studied in NaCl media through weight loss, potentiodynamic, and cyclic polarization techniques. UNS A0332.20S and UNS A0359.20S were reinforced with SiC, 20% by volume while the other two samples were not reinforced. Scanning electron microscopy and energy dispersive spectroscopy were used to analyze the role of intermetallic phases in both the corroded and non-corroded aluminum alloy samples. Results showed that unreinforced alloys have lower corrosion rates compared to the reinforced alloys. Pits on the reinforced alloys were significantly more numerous, shallower, and widespread than on the monolithic alloys. Al/ SiC interface particles and intermetallic phases were observed to form at the mouth of the pits especially in alloys reinforced with SiC particles which might have contributed significantly to the weakening of regions where localized corrosion occurs. The result shows that intermetallic phases may directly influence the corrosion behavior of the aluminum alloy

Attitudinal Correlates of Some Selected Nigerian Librarians towards the Use of ICT

The explosion of information communication technology (ICT) since the beginning of the 20th century has been rendering manual-based library system in academic, research, special and public libraries less relevant. This is because using and implementing information communication technology in the library depend largely on the librarian attitude toward the current digital age. This study examined the attitudinal correlates of some selected Nigerian Librarian towards the use and application of ICT in their various libraries. A total of 41 librarians from all the four censured automated libraries in Oyo state of Nigeria formed the study’s population. Two research questions were developed to guide the study. The results indicate that all the four out of the five variables age, gender, educational qualifications and prior knowledge of ICT significantly correlate with librarian attitude towards ICT; while the other variable ICT anxiety correlate negatively with the librarian attitude towards ICT. Findings further show that all the 5 variables significantly predict librarian’s attitude towards ICT with prior ICT experience showing the greatest predictive effect. Based on these findings, it is recommended that libraries in the developing countries should consider training those librarians who do not have knowledge of ICT in order to remove the fear and anxiety hindering them from developing good attitude towards the use of ICT in their libraries

Income mix and liquidity of Nigerian deposit money banks : evidence from dynamic panel models

Liquidity crunch is one of the greatest challenges that deposit money banks are confronted with which negatively affect their strength and stability and ultimately leading to collapse of some. Arising from this, the study focused on the “effect of income mix on liquidity of Nigerian deposit money banks.”The study adopted an ex post facto research design, while ten out of all the listed banks were purposefully selected. The study obtained secondary data from the annual reports and accounts of the sampled banks from 2008 to 2017. Series of preliminary analyses involving descriptive and correlation analyses were conducted while generalized method of moment was employed in testing the hypotheses. The study found that all the variables of interest on income mix individually exhibit no significant effect on liquidity (P > 0.05), in effect, ratio of interest income, fee and commission income, foreign exchange income and other income were found to influence liquidity negatively while investment income was found to exert positive effect on liquidity. The study’s conclusion arising from the findings is that income mix has significant positive joint effect on liquidity management. Arising from the conclusion, the study recommends that bank should keep diversifying their income base as such strategy significantly improves liquidity, while also improving on the interest income, fee and commission income, foreign exchange income and other income.peer-reviewe

Formulation and Evaluation of Polyherbal Antioxidant Face Cream Containing Ethanol Extracts of Psidium Guajava and Ocimum Gratissimum

Background: Aging is a natural progressive process that leads to aesthetic and functional changes in the skin. The aim of this research work is to formulate and evaluate a polyherbal antioxidant face cream using the ethanol extracts of psidium guajava and ocimum gratissimum.Method: The ethanol extract of the herbs was incorporated at varying concentrations into six different emulsion bases. Antioxidant activity of the formulations was assessed using 2, 2-Diphenyl-1-picrylhydrazyl method. The formulations were evaluated for pH, viscosity, spreadability and microbial content. Accelerated stability tests were performed on all the formulations to assess stability at varying storage conditions.Results: All the formulations showed good spread ability, good consistency, homogeneity, appearance, pH without phase separation occurring. Rheological tests showed that the all formulations exhibited non-Newtonian pseudo plastic flow. All six formulations also showed concentration dependent antioxidant activity. Ascorbic acid a potent antioxidant served as the standard for these tests. Formulation AFCR6 showed the highest antioxidant activity with IC50 value of 80.1 μg/mL.Conclusion: The polyherbal antioxidant cream containing extracts of Psidium guajava and Ocimum gratissimum have been shown to have excellent antioxidants properties. It can serve to protect the skin from reactive oxygen species created by UV radiation and environmental toxin, thus protecting the skin from photo aging.Keywords: Anti-oxidant, Face cream, Psidium guajava, Ocimum gratissimu

Corrosion of Aluminum Metal Matrix Composites: A Review of the Effect of Manufacturing Processes, Processing Routes and Secondary Phases

The vulnerability of Al matrix composites to general and preferential corrosion is due to the intrinsic proneness of binary materials to undergo advanced deterioration. Control of the prevalent sites for evolution and proliferation of confined corrosion strongly influence the corrosion resistance of the composites. The problem for enhanced utilization of composites, has exacerbated with attention on the productive life and resilience to environmental degeneration during operational service. This can be achieved through proper comprehension of the electrochemical mechanism, the intriguing nature of SiC grains and their importance on the secondary phases, metallurgical configuration, and manufacturing process routes. This review confirms the relevance of secondary phases, microstructures and manufacturing processes in relation to SiC particles on the corrosion invulnerability of Al matrix composites to further add corrosion mitigation in design and and technological advancemen

Design and Construction of a Pure Sine Wave Inverter

This research is a design and implementation of a sine wave inverter circuit developed to run AC appliances at a low cost which high efficiency. The design consists of two stages i.e. the DC-DC step up stage and a DC-AC Inverter stage. The DC-DC step up converter is based on a push-pull design to step 24VDC to 300VDC. Pulse width modulation was used i.e. the SG3525 pulse width Modulator. The DC-AC inverter stage comprised of four power mosfets in an H-bridge configuration, driven by a 40 kHz square wave encoded/modulated by a 50Hz sine wave that was derived from a TL084 quad op amp sine wave oscillator. An output voltage range of about 240-260VAC from 300VDC input was obtained. A low pass filter was used to filter out the high frequencies and thus isolate the harmonics so a 50 Hz fundamental frequency was retained

OPTIMIZATION OF BIODIESEL PRODUCTION FROM WASTE FRYING OIL OVER ALUMINA SUPPORTED CHICKEN EGGSHELL CATALYST USING EXPERIMENTAL DESIGN TOOL

An optimization of the biodiesel production from a waste frying oil via a heterogeneous transesterification was studied. This present study is also aimed at investigating the catalytic behaviour of the alumina supported eggshell (ASE) for the synthesis of biodiesel. A synthesized ASE catalyst, at various mixing ratios of alumina to eggshell, was investigated and exhibited a better activity for the reaction when the eggshell and alumina were mixed via incipient wetness impregnation in 2 : 1 proportion on a mass basis and calcined at 900 °C for 4 h. The as-synthesized catalyst was characterized by basicity, BET, SEM, EDX, and FTIR. The 2k factorial experimental design was employed for an optimization of process variables, which include catalyst loading, reaction time, methanol/oil molar ratio and reaction temperature and their effects on the biodiesel yield were studied. The optimization results showed that the reaction time has the highest percentage contribution of 40.139% while the catalyst loading contributes the least to the biodiesel production, as low as 1.233 %. The analysis of variance (ANOVA) revealed a high correlation coefficient (R2 = 0.9492) and the interaction between the reaction time and reaction temperature contributes significantly to the biodiesel production process with percentage contribution of 14.001 %, compared to other interaction terms. The biodiesel yield of 77.56% was obtained under the optimized factor combination of 4.0 wt.% catalyst loading, 120 min reaction time, 12 : 1 methanol/oil molar ratio and reaction temperature of 65 °C. The reusability study showed that the ASE catalyst could be reused for up to four cycles and the biodiesel produced under optimum conditions conformed to the ASTM standard

Prevalence and Characterization of Salmonella Isolates from Poultry Farms in Ilorin, Nigeria

Poultry birds are very important source of essential proteins in developing countries, but also play an important role in transmission of Salmonella to human and nonhuman. Exposure to this pathogen also occurs through use of poultry droppings as manure for crop and vegetable production. This study investigated prevalence of Salmonella in feces of poultry farms in Ilorin, Nigeria. Salmonella isolated were further characterized by molecular method. Fecal samples were cultured in pre-enrichment medium, Selenite F medium and finally sub-cultured on Salmonella-Shigella agar. None lactose fermenting colonies with black center were picked for presumptive identification using biochemical tests and confirmed by serological test by method previously described. Molecular characterization was carried out using 16S rRNA gene sequencing following standard procedure. Out of 170 samples collected and examined, 8 (4.7%) gave biochemical characteristics that resembled Salmonella, but only 6 (3.5%) were confirmed as Salmonella by polyvalent antisera. Molecular characterization revealed that serovars isolated were Salmonella Enteritidis 3 (1.8%) and Salmonella Paratyphi 3 (1.8%). Phylogenetic tree constructed by neighbor-joining method as derived from analysis of the 16S rRNA gene sequences showed close relationship to Salmonella Paratyphi strain FB0015 16S ribosoma RNA gene partial sequence to our Salmonella Paratyphi isolates. The detection of 3.5% prevalence rate of Salmonella serovar from feces of laying poultry birds my serve as potential source of transmission of this pathogen to human through chicken meat, egg or use of poultry dropping as manure in crop or vegetable production

Natural Convection Heat Transfer and Entropy Generation Analysis in Saltbox Roof under Summer Conditions

This study investigates numerically the 2D laminar natural convection in a Saltbox roof type geometry under summer climate conditions as obtained in Africa, particularly Nigeria using ANSYS FLUENT to model the boundary conditions. The effects of Rayleigh number (Ra) within the range of 103-107 and pitch angles (top and base) on heat transfer, the flow structure, temperature distribution and entropy generation within the geometry were analysed. Results show that the flow is nearly symmetric at lower Ra, while for higher Ra, the flow becomes asymmetric. The Nusselt number (Nu) has a proportional relationship with the top pitch angle and an inverse relationship with the base pitch angle when the Rayleigh number is fixed. The effect of the Ra on the Nu is insignificant at lower Ra, but becomes noticeable at higher Ra. The total entropy generation increases with an increase in top pitch angle and a decrease in base pitch angles, at fixed Rayleigh numbers. The physical implication is that, for a Saltbox roof type geometry, at fixed Ra, the best convective heat transfer process is achieved by lowering the base pitch angle and increasing the top pitch angle

Relationship Between Gestation Length and Birth Weight in Nigerian Sheep and Their Crosses

Effect of genotype and birth weight on gestation length was evaluated using Nigerian breeds of sheep and their crosses. The study was carried out at the Sheep Project Unit of Small Ruminant Research Programme (SRRP) of National Animal Production Research Institute (NAPRI), Ahmadu Bello University, Shika-Zaria. The sheep breeds used were Balami, Uda and Yankasa. Heat (estrus) detection was carried out twice daily; in the morning (07:00-08:00 hours); and in the evening (16:00-17:00 hours) using apron fitted rams to pick does on heat. A total of 56 lambs were used for this study. The data obtained were subjected to analysis of variance using General Linear Model and Correlation Procedure of SAS. All the genotypes had similar gestation length with values between 150.3±0.61 days and 153.3±0.60 days, except for Balami pure breed (BAL X BAL) lambs that recorded a shorter gestation length (137.1±0.81 days). There was a wide variation in the birth weight of lambs with the crosses between Balami rams and Yankasa ewes recording a distinct birth weight of 3.5±0.08 kg while the crosses obtained using Yankasa rams on Uda and Balami ewes gave the lowest birth weights (1.7±0.19 and 1.4±0.18, respectively). Sex and litter type have no significant effect (P>0.05) on gestation length. Birth weight was however affected by sex of lambs and their litter type. Litter type was negatively correlated with birth weight (-0.372). Gestation length had a low and non-significant relationship with birth weight; litter type and lamb genotype. Lamb genotype does not have a significant relationship with litter type. Genetic improvement of Nigeria sheep breed is possible if the resources of within and between breed is exploited. Selection for a reduction in gestation length may indirectly increase prolificacy. (Animal Production 12(3): 135-138 (2010