Mathematical Modelling and Optimization of the Compressive Strength, Hardness and Density of a Periwinkle-Palm Kernel and Phenolic Resin Composite Brake Pad

A composite of periwinkle shell powder, palm kernel shell powder, phenolic resin and other additives was developed in a form of a pad. Specimen composite samples were produced by compression at a temperature of 140 °C and mixture design using Design Expert software was used to analyse and optimise the samples. Mathematical models of the compressive stength, hardness and density were developed and statistically validated. Comparison of the models with experimental results showed that the compressive strength suited best with the cubic model, the hardness fitted with quadratic while the density agreed with all the models but suited best with cubic model. Optimized formulation with an objective of maximization compressive strength and hardness and minimization of the density was determined at 10.02, 10.78, 59.20 and 20 % of periwinkle shell powder (filler), palm kernel shell powder (filler), phenolic resin (matrix) and additives respectively

Modelling and Optimization of the Wear rate, Compressive Strength and Hardness of a Composite Brake Pad

A composite brake pad of periwinkle shell, phenolic resin and other additives was developed. The mixture design experiment was adopted using the Design Expert 10.0 software 2017 version and the sample composites were produced using compression molding. Mathematical models of the wear rate, compressive strength and hardness values were developed and validated. The models for the wear rate and compressive strength fitted best with the quartic response model while that of the hardness suited best with quartic and linear models. Comparison of the models with experimental results graphically showed high degree of correlation. An optimized formulation with an objective of minimization of the wear rate and maximization compressive strength and hardness value was determined at 50, 30 and 20% of periwinkle shell powder (filler), phenolic resin (matrix) and additives respectively. Thus the mathematical model can be used to predict the wear rate, compressive strength and hardness value of the experimental design adopted.Key words: periwinkle shell; composite brake pad; quartic mathematical model; wear rate; compressive strength; hardness value; mixture desig

Micro-structural and mechanical characterization of doum-palm leaves particulate reinforced PVC composite as piping materials

A doum palm particulate reinforced polyvinyl chloride (PVC) composite was developed with considerably low cost materials providing an overall light-weight and good mechanical properties for potential application as piping material. The specimen composite material was produced with the doum palm (leaves) particulate as reinforcement using compression molding. Results showed that density and elastic Modulus of the composite decreases and increases respectively with increasing weight fraction of the particulate reinforcement. The tensile strength increased to a maximum of 50 MPa and then decreased steadily. The composition with optimum mechanical property (50 MPa) was determined at 8, 62 and 30% formulation of doum palm particulates (reinforcement), PVC (matrix) and Kankara clay (filler) respectively with corresponding percentage water absorption of 0.72%, Young’s Modulus of 2 GPa, flexural strength of 84 MPa and density of 1.43 g/cm3. Fourier Transform Infrared (FTIR) analysis of the constituents showed identical bands within the range 4000–1000 cm−1 with renown research work. Scanning Electron Microscopy (SEM) result showed fairly uniform distribution of constituents’ phases. X-Ray Fluorescence (XRF) confirms the X-ray diffraction (XRD) result of the presence of minerals of kaolinite, quartz, rutile and illite in the kaolin clay. Comparison with conventional piping materials showed the composite offered a price savings per meter length of 86.6% and 35.9% when compared with carbon steel and PVC material. Keywords: Particulate composite, Mechanical characterization, Spectroscopic analysis, Microstructure, Piping materia

Effects of Operating Conditions on Gas Release Thermal Consequences: a case study of the Trans- Saharan Gas Pipeline

A recent study concluded that militant activities/insurgency constitutes the biggest threat to the proposed Trans-Saharan Gas Pipeline (TSGP) intended to traverse Nigeria, Niger and Algeria. Hence gas release is a credible source of concern. Using the potential leak of inventory from the TSGP as a case study; this paper assesses the Simplex Source Term and Multivariate Consequence Modelling approaches. Aspen HYSYS® platform was used to determine the average Molecular Weight and Lower Heat of Combustion of the gas mixture. Thereafter, the gas discharge rates for various leak scenarios were evaluated. The gas release rates and the flame length of the potential jet fires were initially estimated using Simplex Source Term Models which pay limited attention to operating conditions. Finally a more detailed follow-up study, accounting for a range of practical factors was conducted. A number of useful risk management metrics were determined. For example, the release rate for the 100mm leak is about 130.50 kg/s and 162.13 kg/s for scenarios with and without modifiers respectively. Similarly, the maximum flame lengths were found to be significantly different with values of 8m and 142m with and without modifiers respectively. The results show that the direct approach could be overly conservative, hence more expensive to implement

Mechanical, Spectroscopic and Micro-structural Characterization of Banana Particulate Reinforced PVC Composite as Piping Material

A banana particulate reinforced polyvinyl chloride (PVC) composite was developed with considerabley low cost materials having an overall light-weight and good mechanical properties for potential application as piping material. The specimen composite material was produced with the banana (stem) particulate as reinforcement using compression molding. Results showed that density and elastic Modulus of the composite decreases and increases respectively with increasing weight fraction of the particulate reinforcement. The tensile strength increased to a maximum of 42 MPa and then decreased steadily. The composition with optimum mechanical property (42 MPa) was determined at 8, 62 and 30 % formulation of banana stem particulates (reinforcement), PVC (matrix) and Kankara clay (filler) respectively with corresponding percentage water absorption of 0.79 %, Young’s Modulus of 1.3 GPa, flexural strength of 92 MPa and density of 1.24 g/cm3. Fourier Transform Infrared (FTIR) analysis of the constituents showed identical bands within the range 4000–1000 cm-1 with renown research work. Scanning Electron Microscopy (SEM) result showed fairly uniform distribution of constituents’ phases. X-Ray Fluorescence (XRF) confirms the X-ray diffraction (XRD) result of the presence of minerals of kaolinite, quartz, rutile and illite in the kaolin clay. Comparison with conventional piping materials showed the composite offered a price savings per meter length of 84 % and 25 % when compared with carbon steel and PVC material

The effect of sintering dwell time on the physicochemical properties and hardness of hydroxyapatite with insights from ab initio calculations

Using a low-compaction protocol, the optimum sintering dwell time for fabricating hydroxyapatite (HA) scaffolds was investigated. HA was synthesized through a facile direct thermal conversion approach using a calcination temperature of 900 °C at 2, 4, and 6 h dwell times. The structure and composition of the powders were determined by X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX), and Fourier transform infrared (FTIR) analysis. In addition, porosity measurements were also conducted. Complementarily, computational simulations were conducted from first principles using density functional theory (DFT) with four different exchange-correlation functionals to calculate the structural properties and hardness of the bulk HA crystal. These calculations were done to identify the exchange-correlation functionals that closely agree with the experimental data in this study. The results revealed that with increasing sintering dwell time, the crystallite sizes of the HA powder decreased slightly from 23.62 nm to 23.37 nm, then increased to 34.15 nm. The microhardness of the samples, pre-immersion in phosphate buffer saline (PBS) for 2, 4, and 6 h were 0.38, 0.42, and 0.50 GPa, respectively, whereas post-immersion, the values of the microhardness reached 0.32, 0.48 and 0.54 GPa, respectively. The highest porosity values were 59.3% and 39.3%, observed for samples sintered at 6 h dwell times using the two methods, indicating more open pores. Conclusively, longer sintering dwell time corresponded to better mechanical properties both pre- and post-immersion in simulated body fluid. It was observed that the results from PBE-D3-BJ and optB88-vdW functionals agree better with experimental data for the lattice constants and the values are relatively close to the microhardness obtained experimentally. The reasons for a significant deviation of the microhardness values from the computational and experimental standpoint are discussed herein