Abstract: This research work determined the emission characteristics and elemental composition of selected PVC ceiling materials common in Nigerian markets especially during service. This research work determined the emission characteristics and elemental composition of selected PVC ceiling materials common in Nigerian markets. The emission data and elemental structure gave insight to appraise their suitability as ceiling materials. Three PVC ceiling materials were used for this analysis: Nigerian made PVC, layered Composite PVC and white PVC. Rutherford Backscattering Spectrometry (RBS) was performed to obtain the elemental structure of the ceiling materials using Ion Beam Analysis facility. 0.05 kg of the samples were combusted in a controlled fire chamber and the gasses emitted; CO, SO2, NO, and volatile organic compounds (VOC) were identified using four gas analyzers. Elements were detected in total and data collected from the experiment were analyzed. Results showed that Nigerian made PVC has the highest total noxious gas among the three samples with value of 3732.5 ppm while layered composite PVC has the lowest among the PVCs with the value of 1477.5 ppm. The elemental make-ups of the samples influence their emission characteristics. The study established that PVC samples were noxious in terms of their emission characteristics due to the effects of their elemental basis.

Abstract: Biodiesel was produced from the transesterification of soybean oil using calcium oxide and cow bone (an animal waste bone that contains hydroxyapatite, a calcium phosphate mineral) as heterogeneous catalysts. The soybean oil used was characterized using gas chromatography mass spectrometer (GCMS) and the cow bone catalyst produced was characterized using X-ray diffractometer (XRD) and X-ray fluorescence (XRF) spectrometer. The effects of the variation of methanol/oil mole ratio (9–15), catalyst concentration (10–20 wt/wt%) and reaction temperature (55–65 °C) on biodiesel yield during the transesterification of soybean oil with methanol was investigated. Reaction time of 3 hours and stirring rate of 500 rpm were kept constant. It was observed that the calcination of cow bone catalyst (at 800 °C) enhanced its conversion to apatite [Ca5(PO4)3OH] and increased the yield of biodiesel obtained. Biodiesel yield results revealed an optimum condition of methanol/oil mole ratio of 9, catalyst concentration of 15 wt/wt% and reaction temperature of 55 °C. Also, the results obtained showed that the performance trends of the two catalysts used were similar. And the close values of highest biodiesel yields obtained when the two heterogenous catalysts were used separately (yields of 94.8 and 92.2% using calcium oxide and calcined cow bone catalysts respectively) implies that the use of low-cost and readily available calcined cow bone catalyst is a promising alternative to CaO catalyst.

Abstract: Cu(In,Ga)Se2 or CIGS absorber layers are a promising candidate for thin film solar cells, with efficiency exceeding 22% having already been demonstrated at the cell level and their commercializatio ...

Abstract: This work was supported by Ministerio de Economia y Competitividad (ENE2016-77798-C4-2-R) and Generalitat valenciana (Prometeus 2014/044).