Characterization and morphological properties of glass fiber reinforced epoxy composites fabricated under varying degrees of hand lay-up techniques

In this paper, attempts were made to study the progression of fibre-matrix adhesion of five composite specimens taking into consideration the hand lay-up method of composite formation. The ampreg 21 epoxy resin was used as the matrix for the glass fibre-epoxy resin formation. E- Glass fibre was used as matrix reinforcement. The morphology and the XRD of these composites were examined. Key of the findings from the morphological analysis of these composites showed that the fractured surface of the samples depicted better adhesion between the matrix and the fibres. The micrographs and EDS of the composite specimens also showed the retention of elemental composition of the glass fibre which is in line with other published works. The XRD results of these composites indicated a peak at Bragg’s angle 2θ=20.6o, affirming the remnant crystalline silica in the composite. Hence, these composites are projected to possess better dimensional stability adaptable for high performance structural applications.Keywords: composite, interfacial adhesion, morphology, reinforcing fibr

Reliability of Financial Reporting and Companies Attribute: The Nigerian Experience

This study examines the impact of quoted companies attributes on the reliability of financial reporting in Nigeria. The objective of the study is to investigate whether there is any significant relationship between companies attributes such as size, profitability, age and size of audit firm and the reliability of financial reporting. The data were collected through a secondary source from fifty-one randomly selected quoted companies in Nigeria for the year 2010. The data were analyzed using multiple regression analysis. Our findings show that there is a significant relationship between company size, profitability, age and reliability of financial reporting and a negative relationship between size of audit firm and reliability of financial reporting in Nigeria. Also, the study reveals that profitability is the major companies’ attribute that influences the overall quality of financial reports reliability in Nigeria. The study recommends that there should be provisions in the law dealing with companies’ attributes which have the potential to impair the quality of financial reporting. Similarly, emphasis should be placed on the qualities possessed by the preparers and those who attest to financial statements to show desired outcome. Keywords: Reliability, Companies Attributes, Financial Reporting.

The Impact of Tax Audit and Investigation on Revenue Generation in Nigeria

This study examines the impact of tax audit and investigations on revenue generation in Nigeria. The aim is to determine if tax audit and investigations can actually increase the revenue base of the government and if it can also stamp out the incidence of tax evasion. Data were collected through the primary sources from four hundred and ten respondents who are staff of the Federal Inland Revenue Service and Edo State Board of Internal Revenue. Hypotheses formulated were tested with Pearson Correlation Coefficient using SPSS output data. The findings are that Tax audit and investigations can increase the revenue base of the government and can also stamp out the incidents of tax evasion in the country. It was recommended that Tax audit and investigations should be carried out more often and as thorough as possible to accomplish its task of increasing the revenue base and stamping out tax evasion in the country. Key Words: Tax Audit, Revenue Generation, Investigation

Aliphatic and polycyclic aromatic hydrocarbons profiles of photomodified natural bitumen of Agbabu, Southwestern Nigeria

The impact of sunlight on aliphatic and polycyclic aromatic hydrocarbons profiles of Agbabu natural bitumen in Nigeria was investigated. The raw flow type of the bitumen was purified and exposed to sunlight for six consecutive months. Different portions of the bitumen were withdrawn at an interval of one month and were separated into aliphatic and polycyclic aromatic hydrocarbon fractions by column chromatography, followed by the GC analyses of various fractions. The total aliphatic hydrocarbon content was found to be 485, 424, 416 and 392 g/kg for control, one, three and six months solar-irradiated bitumen samples, respectively; while the total polycyclic aromatic hydrocarbons content found in the control, one, three and six months solar-irradiated bitumen samples were 708, 733, 609 and 638 µg/g, respectively. The effects of sunlight on the compositional patterns of bitumen were discussed. KEY WORDS: Agbabu, Bitumen, Sunlight, GC, Aliphatic hydrocarbon, Polycyclic aromatic hydrocarbon  Bull. Chem. Soc. Ethiop. 2010, 24(3), 461-466

Evaluation of Poultry Manure and Cow Dung on Solanum lycopersicum L Planted on Spent Oil Polluted Soil

Pollution from Spent Lubricating Oil (SLO) is one of the major problems farmers encounter in Nigeria. The study is a completely randomized design with Ibadan Local tomato seedlings grown on the following treatments: 0 ml SLO (control), 75ml SLO, 35g of poultry-manure + 75ml SLO, 35g of cow-dung + 75ml SLO, and 4g of NPK + 75ml SLO replicated four times. Physico-chemical parameters of the soil, poultry manure (PM) and cow-dung (CD), heavy metals, and Total-Petroleum-Hydrocarbon (TPH) were determined before and after pollution using standard procedures. Tomato seedlings were transplanted into pots of amended soil with SLO (5 kg/2 plants) and monitored till maturity. Data were taken on growth, yield parameters and analyzed using ANOVA (p<0.05). Results showed significant differences among the treatments. The soil textural class was sandy-loamy with pH (7.2). Tomato in control plots had the highest values 48.30cm plant-height (PH), number-of-leaves (82.63) (NOL), number-of-fruits (0.98) (NOFR) and fresh-weight (0.55g) (FW). Tomato plants grown on CD amended had the lowest 14.40 cm PH, SLO at 75 ml had 6.00 and 1.71cm for NOL and SD, respectively. The NOFR 0.70 value was from PM amended, FW 0.10g was from SLO at 75ml. Heavy-metals bioaccumulation ranges were: Cu 3.00-36.61mg/kg and Zn 15.00-303.79mg/kg. The final TPHs ranged from 181.66 -1350.00mg/kg, while % TPH removal ranged from 4.69- 53.18%. Cow-dung treated soil reduced the amount of copper and zinc present compared with spent oil soil. The growth performance of tomatoes in this study suggests that soil amendment should be encouraged

Factors influencing CD4 cell count in HIV-positive pregnant women in a secondary health center in lagos, nigeria

Background: Immunity in pregnancy is physiologically compromised, and this may affect CD4 count levels. It is well-established that several factors affect CD4 count level in pregnancy. This study aimed to determine the mean and reference range of CD4 count in human immunodeficiency virus (HIV)-positive pregnant women in Lagos, Nigeria. Methods: A retrospective study was carried out at antenatal clinics of the Maternal and Child Center of a secondary health center in Lagos State, Nigeria. Records of HIV-positive pregnant women at various gestational ages, including CD4+ cell count at booking, packed cell volume (PCV) at booking and labor, gestational age at delivery, and infant weight and sex were retrieved. The descriptive data was given as mean ± standard deviation (SD). Pearson's chi-squared test and correlation were used for analytical assessment. Results: Data were retrieved for a total of 143 patients. The mean age was 31.15±3.78 years. The mean PCV was 31.01%±3.79% at booking and 30.49%±4.80% during labor. The mean CD4 count was 413.87±212.09 cells/µL, with a range of 40 to 1,252 cells/µL. The mean infant weight was 3.05±0.45 kg, with a range of 2 to 5 kg. Age of the mother, gestational age, and PCV at booking were not statistically significantly associated with CD4 count. Conclusion: Maternal age, gestational age, and PCV at booking had no significant effects on CD4+ cell count levels in pregnancy. The mean CD4+ cell count of HIV-positive pregnant women in Lagos is 413.87±212.09 cells/µL

Influence of temperature on the chemical compositions and microstructural changes of ash formed from palm kernel shell

This study investigated the characteristics of raw palm kernel shell (raw PKS) and the influence of temperature variation on palm kernel shell ash (PKSA). The PKSA was obtained under different temperature regimes of 900, 1000, and 1100�C. The characterization of the samples was carried out using X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) with attached Energy Dispersive X-ray (EDX) facilities. The results showed that moisture and ash contents and the density of raw PKS were 6.56%, 8.86%, and 745 kg/m3 , respectively. The colour of the pulverized PKS was dark brown, as observed by visual examination based on standard colour gradation. This colour transformed into various shades of brown when PKS was subjected to different temperature regimes to form PKSA. The XRF analysis showed that silica is the main constituent of the raw PKS and PKSA samples. Silica content in the PKSA increased with the rise in the heating temperature. The FTIR and EDX spectra confirmed the predominance of silicon compounds with functional groups associated with silanol and siloxane. Also, XRD analysis revealed that the silica contents in the samples are quartz, while SEM examinations indicated that temperature increases during processing influenced the microstructure through the reduction of pore concentration in the samples. The silica obtained from the PKSA would find applications in metal matrix composites as partial reinforcing material

MECHANICAL PROPERTIES AND PHASE EVOLUTIONS IN HEAT-TREATED CAST Al-SiC-TiO2 METAL MATRIX COMPOSITES

The effect of heat treatment with an addition of titania on the phase development and mechanical properties of sand casted Al-SiC-TiO2 metal matrix composite was investigated. The standard samples dimensions for tensile properties, wear and hardness were prepared. These samples were heat treated at different temperature of 180°C to 220°C without solution treatment. The samples were held at the heat treatment temperature for an hour after which they were allowed to cool in the air. Thereafter, samples were subjected to various mechanical and wear tests, respectively. The phases evolved due to heat treatment of the samples were examined using X-ray diffractometry. It was observed that the increase in heat treatment temperature of samples leads to the formation of precipitates within the aluminium matrix composite reinforced with SiC. The addition of 5 % titania inhibits the formation of aluminium silicon carbide phases in preference to SiO2 and TiO2 . The increase in heat treatment temperature leads to the formation of precipitates like TiSi2 , Si11.4TiO24.4, TiC, Al2 O3 and buckminsterfullerene C70 within the aluminium matrix composite. The addition of 10 % titania leads to the development of precipitates like Al5 Ti3 and Ti-rich oxides with the aluminium matrix. At 220°C, alumina was formed within the metal aluminium matrix and no trace of SiC was found. All the samples have low wear loss but the heat treated at 180°C sample (A) has the lowest wear loss. The heat treatment of the sample without solution treatment has impact on the phase development in the samples. It gives rise to the development of precipitates in the samples which affects the hardness and other mechanical properties. The addition of SiC and TiO2 to aluminium matrix makes the sample harden. Sample A heat treated at 200°C have the highest hardness

Modelling and Optimization of Laser Alloyed AISI 422 Stainless Steel Using Taguchi Approach and Response Surface Model (RSM)

This research paper demonstrates the application of Taguchi method and Response surface Methodology (RSM) for optimization of alloyed depth in laser alloying of AISI 422 martensitic stainless steel. The experiment was designed and carried out on the basis of standard L9 Taguchi’s orthogonal array in which three laser processing parameters such as laser power, scanning speed and powder feed rate were arranged at three levels. The processing parameters played an important role in the quality of alloyed coating produced and proper control of these processing parameters resulted in quality alloyed depth and hardness property. From the analysis of mean values of variance (ANOVA) and response surface numerical analysis, the significant laser processing parameters were indentified. The results showed that laser power and scanning speed are the most significant parameters affecting the alloyed depth of laser surface alloying (LSA), while the influence of powder feed rate is much minimal