Effects of Increasing Chitosan Nanofibre Volume Fraction on the Mechanical Property of Hydroxyapatite

This work attempted to synthesize chitosan (CH) nanofibre from crab shell and hydroxyapatite, HA, from limestone with the objective of studying the effects of increasing volume fraction of chitosan nanofibre on the mechanical properties of HA. Mechanical characterization of different fraction composite was carried out to study the effects of increasing volume fraction of chitosan nano fibre on the mechanical properties of HA. In addition, surface characterization of the composite was carried out using Fourier Transform Infrared Spectrometry, FT-IR. Results obtained indicated that the optimum mechanical properties were obtained at a volume fractions of 30: 70, CH: HA respectively; average compressive strength of 10.12 MPa; average tensile strength of 173.9 MPa; average hardness value of 420.80 HV; average fracture toughness of 14.72 MPa.m1/2; average elastic modulus of 0.1583 GPa and average bending strength of 157.96 MPa were obtained for this optimum volume fractions. Increasing volume fractions of chitosan nanofibre was therefore found to result in decrease in compressive strength, hardness and elastic modulus of HA while its tensile strength, bending strength and fracture toughness increased. The FTIR revealed that possible interaction between the NH2 group and the primary and secondary –OH group of CH with Ca2+ (metal coordination interaction) of HA might be responsible for the higher mechanical property of HA. In conclusion, it was found that increasing chitosan volume fraction in chitosan/HA composite results in increasing strength of hydroxyapatite, consequently enhancing its load bearing ability

Inventing a New Africa through Discovery and Innovations in Computational Material Science

Researchers are increasingly relying on computational technologies to help in simulation of properties of new materials and some areas in materials science has enjoyed some level of success which ranges from composites, to polymer science and to advanced ceramics. This review paper discuss certain developments in the area of computational Materials and how Africa can leverage on this technology to develop their emerging Industries, while dwelling more on application of computational material science in energy sector, since energy has been most pressing challenges in Africa which could be addressed by advanced materials. Also, we summarize part of our research work on galvanic corrosion of mild steel bolt in a magnesium alloy (AZ91D) plate simulation using comsol Multiphysics and 2k factorial experiments on factors that influence the recovery of gold during the upgrade of Ilesha-Itagunmodi, Nigeria gold ore through Froth flotation using Anova software. Attempt have been made to identify existing computational method, challenges of computational materials science deployment in Africa, and how material development can be accelerated through the power of computational material science. With this work, we were able to establish that the strength of computational materials science is in making a connection between the experiment and theories of complex phenomena

Inventing a New Africa through Discovery and Innovations in Computational Material Science

Researchers are increasingly relying on computational technologies to help in simulation of properties of new materials and some areas in materials science has enjoyed some level of success which ranges from composites, to polymer science and to advanced ceramics. This review paper discuss certain developments in the area of computational Materials and how Africa can leverage on this technology to develop their emerging Industries, while dwelling more on application of computational material science in energy sector, since energy has been most pressing challenges in Africa which could be addressed by advanced materials. Also, we summarize part of our research work on galvanic corrosion of mild steel bolt in a magnesium alloy (AZ91D) plate simulation using comsol Multiphysics and 2k factorial experiments on factors that influence the recovery of gold during the upgrade of Ilesha-Itagunmodi, Nigeria gold ore through Froth flotation using Anova software. Attempt have been made to identify existing computational method, challenges of computational materials science deployment in Africa, and how material development can be accelerated through the power of computational material science. With this work, we were able to establish that the strength of computational materials science is in making a connection between the experiment and theories of complex phenomena

Investigation of Physicochemical and Mechanical Property of UTAN Granites for Building Applications

The granite formation for production of dimension stone blocks at Utan was investigated in three different locations A, B and C in a view to examine the physical properties of Utan granite using saturation and Buoyancy technique; evaluate some of its mechanical properties; determine its rate of emission of radioactive elements with Geiger Muller Counter; examine its polish-ability; and carry out chemical analysis of the granite samples with the aid of energy dispersive x-ray florescence (ED-XRF). The average porosity obtained is 0.53, 1.08; and 0.86 while the respective average density of 2.58, 2.62 and 2.60 g/cm3 were obtained for A, B and C. The compressive strength of 207.5, 204.6 and 203.4 MPa; and tensile strength of 13.86, 13.68 and 13.60 MPa were obtained for A, B and C respectively. Rockwell hardness values obtained are 89.0, 89.9 and 86.6 while the morh’s hardness values are 6.90, 6.96 and 7.03 respectively for sample A; B and C. The impact values obtained are 0.089, 0.092 and 0.094 for A, B and C respectively. The radioactive rates of samples A, B and C are 6.42, 8.86 and 8.16 Mrem respectively. Sample B is observed to be more radioactive. Both samples are polish able. Conclusively, the three tested granite rocks have suitable physical and mechanical properties that meant the requirement for building purposes; from the polish-ability test, it shows that the three (3) granite outcrops are suitable for the production of granite tiles; countertops; slabs. The chemical analysis revealed that the granite is dominated by quartz (SiO2) which contributes greatly to the hardness of the rock. Also from the radioactive test, the granite samples proved conclusively that the rate of radiation found occasionally in a slab of granite is not harmful to humans when exposed to it. Hence, granite the formation of Utan will be a good building stone material

Comparative Study of Local Mining Methods and Assay of Cassiterite with other Alluvial Mineral Deposits in Kuru-Jantar, Plateau State, Nigeria

This research attempt to investigate and compare the local mining methods of cassiterite in Kuru-Jantar with the view to determine the mean recovery per day using statistical approach, separating the valuable minerals through the gravity and magnetic techniques, determine the grade of cassiterite (tin oxide) with the aid of volumetric and energy dispersive x-ray florescence (XRF) analyses; and determine the percentage composition of metals in cassiterite as well as its associate ores with the aid of (XRF). Sub-surface (lotto) and surface (Hand paddock) mining methods were carried out and the respective recovery from each of the method was subjected to processing, sampling and assaying to determine the quantity, quality (grade) and expected smelter-yield. The mean recoveries per day are 14.48 and 11.28 kg/day for lotto and paddock mining methods respectively. The burretting differential obtained for the lotto and paddock methods are 18.80 – 19.80 and 18.80 – 19.30 respectively while their respective percentage tin metal burretted are 90.40 – 97.83 and 92.51 – 97.80 %. The recoveries from the magnetic and gravity separations are 10.91 kg and 9.06 kg for lotto and paddock methods respectively. The XRF analysis gave 68.69 and 66.462 % Sn respectively for the lotto and paddock while the assaying of other associate minerals are 40.4 % Nb; 26.5 % Fe; 22.3 % Ti; 2.5 % Ta; 2.3 % Sn; and 5.1 % W for the paddock and 37.6 % Nb; 24.8 % Fe; 21.5 % Ti; 2.3% Ta; 5.8 % Sn; and 4.9 % W for lotto. It can be observed that the lotto mining method has the highest recovery per day and hence, gives better recovery than paddock mining method. Lotto mining was found to yield higher grade tin-ore concentrate than the hand paddock mining method in both volumetric and XRF analyses but hand paddock gives higher quantity and more associate minerals. It was also found out that the lotto method is more risky and life threatening than paddock mining while the paddock mining practices render more danger to environment than the lotto mining

Assessment of microstructure, nanomechanical and tribological properties of Ti-xNi alloys fabricated by spark plasma sintering

This work employed the nanoindentation and conventional dry sliding wear techniques to study the nanomechanical and tribological properties of the spark plasma sintered Ti-xNi (x = 2, 6 and 10 wt%) alloys. The microstructure and phase composition of the fabricated alloys were studied. The results indicated the presence of hexagonal close-packed (hcp) α-Ti and face-centred cubic (fcc) Ti2Ni intermetallic phases within the matrix of the Ti-xNi alloys. Nanoindentation measurements under varying loads showed that the hardness (H), elastic modulus (Er) and elastic recovery index (We/Wt) of the developed alloys increased with increasing nickel contents. At a constant load, the hardness trend aligns perfectly with the indentation size effect phenomenon. The H and Er decreased upon transition from lower to higher loads. The H/Er and H3/Er2 ratios obtained from nanoindentation are higher for Ti-xNi alloys compared to pure Ti. This shows that the Ti-xNi alloys possessed better anti-wear characteristics than pure Ti. The wear analysis results show that the wear resistance increased with increasing volume fraction of the Ti2Ni intermetallics in the sintered samples. Ti–10Ni alloy displayed the best nanomechanical and wear performances among the sintered samples

Process parametric optimization of spark plasma sintered Ni–Cr–ZrO2 composites using response surface methodology (RSM)

Materials properties are highly dependent on the processing parameters and technique used during sintering. The effect of Spark Plasma sintering process parameters (pressure and temperature) on the hardness and relative density of Ni–20Cr–5ZrO2 composite was investigated. Response Surface Methodology (RSM) from the design of experiment (DOE) technique was successfully employed for the experimental design, and statistical analysis was conducted on the obtained experimental results. The microstructural analysis of the sintered composite showed the presence of solid solution phases of Ni and Cr, which were confirmed by the XRD results as (Cr,Ni) alongside unreacted ZrO2 particles at sintering temperatures of 950 °C and 1000 °C. The validity of the model developed with the impact of each variable and their corresponding interaction on the responses was performed using analysis of variance (ANOVA). The relative density and hardness were the two responses considered. The actual values (experiment data) and expected values (simulated data) were subjected to statistical analysis, to develop a predictive model that synchronizes density and hardness as distinct process parameters, with material hardness and relative density serving as the responses of the specified experiment. For the responses, quantitative models were created, and 10 experimental runs were processed to ascertain the desirability of the responses. The SPS processing parameters considered the most desirable were 1000 °C sintering temperature and 50 MPa pressure. The hardness property obtained under this condition is 433.23 HV with a relative density of 98.15%