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The development of several novel multifunctional components to perform specific unique functions is directed towards meeting the demands for advanced components in industries. In this study, the role played by carbon (C gr ) variation on the steel part composition of cemented tungsten carbide and steel bilayer processed via powder metallurgy was investigated. Microstructural examination through field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS) revealed the presence of detrimental eta carbide phase (M 6 C) distributed across the interface of sintered bilayer compacts. A significant reduction of M 6 C was observed with 0.8 wt.% C gr when interlayer diffusion was accelerated resulting in better morphology and higher hardness values of 735.70 and 150.97 kgf mm −2 in WC and Fe layers, respectively. Tensile strength property was evaluated to examine the sintering compatibility and the interfacial bond strength of bilayer specimens. Excellent bond strength was achieved in all sintered bilayer with increasing C gr level and enhanced densification which consequently improved tensile strength by 19%.

A porous ceramic is made from composite materials which consist of alumina and commercial rice husk ash. This type of ceramics is obtained by mixing the commercial rice husk ash as a source of silica (SiO2) and a pore forming agent with alumina (Al2O3) powder. To obtain this type of ceramic, a solid-state technique is used with sintering at high temperature. This study also investigated the effects of the rice husk ash ratios on the mechanical properties, porosity, and microstructure. The results showed that, by increasing the content of the rice husk ash from 10 to 50 wt%, there is an increase in the porosity from 42.92% to 49.04%, while the mechanical properties decreased initially followed by an increase at 30 wt% and 50 wt%; the hardness at 20 wt% of the ash content was recorded at 101.90 HV1. When the ash content was increased to 30 wt% and 50 wt%, the hardness was raised to 150.92 HV1 and 158.93 HV1, respectively. The findings also revealed that the tensile and compressive strengths experienced a decrease at 10 wt% of the ash content and after that increase at 30 wt% and 50 wt% of rice husk ash. XRD analysis found multiple phases of ceramic formation after sintering for the different rice husk ash content.

The development of multilayered components is essential to modern-day technological operations. Several routes to develop these components have emerged, but powder injection molding (PIM) has the benefits of simplicity, non-formation of a third layer, and near-net-shape production. However, PIM presents the challenges of shrinkage mismatch and formation of undesirable phases, which deteriorate the quality and integrity required in multilayered components. The sintering process has been identified as the key step in this route where defects originate; therefore, its parameters (temperature, time, rate, and atmosphere) must be carefully controlled and monitored. This review touches on various processing routes in developing multilayered components, cuts across the achievements made so far in the PIM route majorly in controlling the sintering response of layers, and then sets some guidelines and highlights possible gray areas for future research studies. Some measurement techniques deployed to evaluate shrinkage during sintering, and numerical simulation analyses of PIM processes are also described and analyzed. Thus far, only few mechanical properties have been successfully evaluated in the literature and are discussed in this article.

Bio-based polyurethane (PU) was synthesized from waste cooking oil-based polyol for application as host in solid polymer electrolyte. The effect of varying wt% of lithium iodide (LiI) salt as charge carriers was studied. The polymer electrolyte films were characterized using Fourier transform infrared (FTIR), electrochemical impedance spectroscopy, scanning electron microscope (SEM), differential scanning calorimeter and thermogravimetric analysis. The shifting of absorption peaks for amine (N–H), carbonyl (C=O) and ether (C–O–C) groups observed in FTIR analysis showed that the PU-LiI complexation had occurred. The highest ionic conductivity obtained was at 30% LiI with value of 4.67 × 10 −6  Scm −1 . SEM revealed the good miscibility between lithium salt and PU. These properties exhibited the potential of waste cooking oil-based PU as alternative host for solid polymer electrolyte.

Polyurethane is a versatile polymer traditionally prepared using petroleum-based raw material. Petroleum, however, is a non-renewable material and polyurethane produced was found to be non-biodegradable. In quest for a more environmentally friendly alternative, wastecooking oil, a highly abundant domestic waste with easily derivatized structure, is a viable candidate to replace petroleum. In this study,an investigation to determine physical and chemical properties of rigid polyurethane (PU) foam from waste cooking oil (WCO) was carried out. WCO was first adsorbed by using coconut husk activated carbon adsorbent prior to be used for polyol synthesis. The purified WCO was then used to synthesize polyol via transesterification reaction to yield alcohol groups in the WCO chains structure. Finally, the WCO-based polyol was used to prepare rigid PU foam. The optimum formulation for PU formation was found to be 90 polyol: 60 glycerol: 54 water: 40 diethanolamine: 23 diisocyanate. The rigid PU foam has density of 208.4 kg/m3 with maximum compressive strength and capability to receive load at 0.03 MPa and 0.09 kN, respectively. WCO-based PU can potentially be used to replace petroleum-based PU as house construction materials such as insulation panels.

The aim of the present research is to examine the effect of Cu metal addition in nano-scale particle size on the mechanical properties and porosity of porous alumina ceramics using commercial rice husk ash as pore forming agent and silica (SiO2) source. Porous alumina ceramics reinforced were prepared using nano-scale Cu metal particles as their strengthening phase. Solid-state and sacrificial techniques were used to prepare the porous alumina reinforced ceramics. A field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and transmission and electron microscope (TEM) were used to analyze the microstructure and ceramic phases. Different ratios of Cu metal were added (3, 6, 9, and 12 wt%) at different ratios of commercial rice husk ash. The results of this investigation show that with increasing ratios of Cu metal, the porosity decreased and the mechanical properties increased. The increase in the mechanical properties could be attributed to the decrease in the porosity, the toughening mechanism, increase density of porous alumina ceramics, and formation of the tenorite (CuO) phase due to sintering at high temperature (1600 °C). Some potential applications include purging of gas filtration and thermal insulation.

In this article, the effect of sintering temperature was studied on the microstructure and hardness of cemented tungsten carbide and steel bilayer fabricated via the powder metallurgy route. Cemented tungsten carbide was reinforced with Fe and also used as the base material for the other layer to ensure compatibility between layers. Carbon addition was varied in the steel part composition to avoid carbon-deficient bilayer samples. Optical images revealed cracks at the interface which opened up more in bilayer samples sintered at 1295°C due to high mismatch in strain rate and excessive diffusion rate. Increase in sintering temperature turned grain particles coarser and lead to a decline in hardness values while increase in carbon addition enhanced densification and progressively increased hardness. Hardness values measured far away from the interface were observed higher than those close to the interface due to the formation of weak bond at the interface.

To compare the adverse fetometernal out come in overweight and normal weight pregnant women. This comparative cohort study was conducted from 1(st) October 2010 to 30 September 2012. Total 200 gravid women 100 were overweight and 100 normal weight pregnant women with gestational age for 08-40 weeks were included. Women having BMI (25 - 29.9 Kg/m(2)) were measured overweight and included in group A and 100 women having normal BMI of 18.5 to 24.9 as controls were in-group B. Chi-square test was applied to compare the proportion of maternal and fetal outcomes. Significant P - value of < 0.05 was considered. The age range was between 30 to 45 years with mean age of 30±4.1 years in both groups. Overweight pregnant women had significantly high frequency of pre-eclampsia (27% versus 9% in controls), PIH (24% versus 8% in controls), gestational diabetes mellitus (22% versus 5% in controls), prolonged labour (4% versus 6% in controls), Caesarean section (44% versus 16% in controls), Wound infection (3% versus 2% in controls) and Postpartum Hemorrhage (5% versus 2% in controls). P-value < 0.001 was considered significance. Fetal complications in overweight pregnant women compared to controls i.e. Still birth (13% versus 2%), Early neonatal death (11% versus 1%), shoulder dystocia (5% versus 1%) and NICU admission (47% versus 10%). Results were statistically significant except shoulder dystocia. We conclude that the result of present study indicates obesity exerts deleterious effect, both on fetal and maternal outcome.

Microwave processing of ceramics is fast emerging as a new field of ceramic processing and material synthesis. The past year has witnessed significant progress in the aspects of commercialization and application of the technology in new areas. Due to that reason, several experiments were conducted on microwave heating of ceramics. The aim of the study is to investigate i) whether microwave is a viable alternative to produce sintering parts, ii) the effect of soaking time on the properties of the sample, and iii) the influence of several binders including nickel, ferum, chromium and cobalt to tungsten carbide cermets. The study involved studying the density, hardness and microstructure of the sintered samples. The samples were compacted using an Instron machine at 200 MPa in a cylindrical shape using pallet press with a height of 10 mm and a diameter of 20 mm and sintered in microwave hybrid sintering at 1450°C for two different soaking time (10 min and 20 min). The soaking time of 10 min showed better density, hardness and microstructural results compared to those of 20 min. In comparing between the binders, Ni and Fe (Ni-Fe) showed better results compared to Ni and Cr. While cobalt, nickel and ferum (Co-Ni-Fe) had enhanced results compared to Co and Cr (Co-Cr). Although there are a lot of research studies on several other binders, there is still no finding on the use of microwave hybrid sintering to sinter different mixing binders of tungsten carbide cermets. Therefore, in this research, it is believed that the use of microwave hybrid sintering is viable to sinter tungsten carbide cermets with different binders. The density result showed that each composition of the sintered density was higher compared to green density, which increased by 30% than the green density on average. On the other hand, the hardness results from the commercial cutting tool for tungsten carbide cermet was in the range of 80 to 92 HRA and the highest result for hardness in this research was 84.3 HRA, which means that the insert can be used for commercial use depending on the application

In this study, the ejection stage during the densification process and the mechanical strength of green (unsintered) compact were studied for the binary powder compact of iron and micro crystalline cellulose (MCC). The mass percentage of MCC powder were varied between 0% to 60% of the total mass composition of the iron and MCC mixture. Three different compaction load of 30kN, 60 kN and 90 kN were applied during the compaction process. The tensile strength of the green compact was determined by conducting diametral compression test where the green compact was loaded until fracture. From the compaction experiment, green compact with 60% MCC and 40% iron is the least friable which leads to coherent and well compactable powder. This composition also results in the green compact with the highest tensile strength.