Aims: The aim of the study is to evaluate polyurethane wood ash composites characteristics and reliability.
Study Design: Experimental Study Design was used in the study.
Place and Duration of Study: The study was conducted in the faculty of Engineering workshop, Nnamdi Azikiwe University, Awka, Nigeria from October 2017 and February 2018.
Methodology: Three independent parameters employed include carbonisation temperature, particle size and volume fraction. Gmelina arborea samples were sundried and carbonised at varied temperature (400,700 & 1000°C), sieved to three particle sizes (75, 150 & 300 μm) and reinforced at varied volume fractions (30, 40 & 50%) with Polyurethane elastomeric polymer. The mechanical properties of the various samples prepared were tested and Weibull statistics was adopted in strength analysis of the composite.
Results: The results obtained showed that varying carbonisation temperature resulted in different mechanical properties of the wood ash composites with the best improvement occurring at 50% volume fraction, having 300 μm particle size at carbonisation temperature of 700°C. However, decrease in the density of the composite was noticed when the fiber volume fraction increased. In all cases, carbonisation above 400°C showed improved mechanical properties as a result of increased carbon yield and reduction in tar and moisture content.
Conclusion: A low Weibull modulus of 1.64 suggests that polyurethane wood ash composites has highly variable fracture strength, making it difficult to be used reliably in load-bearing applications, however more useful applications of the new material may include packaging and containerisation.
Complexes are biologically useful compounds and they have many biological activities. Colchicine can form stable complexes with alkali metals. Till now colchicine complexes have not been characterised by modern mass spectra methods such as MALDI MS (Matrix-assisted laser desorption/ionization mass spectral). The aim of this study was to check fragmentation pathways of colchicine complexes with alkali metals: Li+, Na+, K+ by MALDI MS mass spectra. The colchicine complexes with Li+, Na+, K+ cations of perchlorates and iodides have been synthesised and studied in details by MALDI MS mass spectra.
Alkyd resins are essential raw materials used in the surface coatings and paints industry. In any case, in Nigeria today, alkyd resins are still to a great extent imported partly due to the non-accessibility of a portion of the traditional seed oils that are utilized for alkyd production. The decision of oil is one of the essential contemplations in alkyd resin production. This paper considers the possibilities of using non-traditional seed oil of oilbean from our locally-accessible tropical plants of oilbean, compares it with breadfruit and the most broadly used soybean seed oil for alkyd resin preparation. The physico-chemical and mechanical properties of the alkyd resins synthesized by alcoholysis process gave better results when compared with some conventional alkyd resins. The utilization of oilbean and breadfruit seed oils for alkyd resin synthesis established new process that uses locally accessible crude materials for alkyd production both for modern, structural, industrial and architectural coatings and hence improves the Nigerian economy.
Lead sulphide (PbS) thin films were deposited at different times on a zinc plate substrates using electrodeposition technique at room temperature. The results showed that PbS thin films resistivity has a direct proportionality with time. The optical properties of the thin film were measured using M501 UV-visible spectrophotometer in the wavelength range of 300 nm-1500 nm. The highest and lowest optical absorbance value of 0.253 and 0.219 at 5 mins and 1min respectively were recorded. The transmittance value of 0.582% and 0.966% at 3 mins were recorded in the infrared and ultraviolet regions respectively. The peak reflectance value was attained at 5 mins in both regions, while the minimum was obtained at 1min in the near infrared and visible regions. Refractive index, optical conductivity, extinction coefficient, real dielectric constant and imaginary dielectric constant were examined as a function of the photon energy. Further analysis revealed the band gap to be in the energy range of 1.9eV-2.6eV. These results show that lead sulphide can be used for mass production of solar cells and others photovoltaic devices.
In this work we calculated MgO ab initio X-ray Absorption and Emission spectra using the Full Potential Linearized Augmented Plane Wave method within the Density Functional Theory formalism. The X-ray Absorption and Emission spectra for the K and L2;3 edges of Mg and O atoms were calculated including a core hole in order to study the electronic structure of valence and conduction bands of the system. Both kinds of spectra were compared with experimental data obtaining a very good agreement and the improvement in the spectra due to the use of Tran Blaha modified Becke-Johnson (TB-mBJ)potential is manifested. This potential describes better the insulator properties, produces a band gap that is in good agreement with the experimental value and improves the intensities and the structure of the spectra. Was interesting to find the presence of Mg d states below the Fermi energy in the equilibrium volume of MgO. The XANES experiments were better reproduced by introducing the full core hole in the calculations using TB-mBJ potential while for XES the best agreement was obtained without core hole. The Bader’s topological method was employed to analyse the ionic behaviour. Using the electronic charges obtained with the Bader’s Method and the equilibrium lattice parameter, we obtained the value of the Lattice Energy and we compared it with the value obtained by the Born-Haber cycle showing a good agreement. The charge density for MgO was plotted, and a maximally localized Wannier function for O is shown.