Effect of surface attrition on the microstructure and wear properties of boronized grade 304 stainless steel / Siti Khadijah Alias

Grade 304 stainless steel has an excellent strength to weight ratio and high corrosion resistance; unfortunately it possesses very poor wear resistance. The structure of this type of stainless steel is austenitic and cannot be heat treated. This study focused on the effect of surface attrition using the shot blasting method on the surface of boronized grade 304 stainless steel. Boronizing was conducted at temperatures of 850˚C and 950˚C under two types of mediums which were powder and paste for the duration of 8 hours holding time. Boronized samples with thicker boride layer and superior wear properties were thus selected to undergo surface attrition using shot blasting method. The microstructure analysis and boride layer thickness were observed using optical microscopy, scanning electron microscopy (SEM) analyzer and energy dispersive X-Ray (EDX) spectrometry. Other tests such as pin on disc, erosion, microhardness, surface roughness and density were also conducted

Fuzzy Delphi Method Application Towards Usability Evaluation of Problem Solving Framework: Application in Education

Non-digital games are tools that can help children build and improve problem-solving skills. Children need to solve problems using analogies from one situation to another, following the correct steps. To improve these skills, teachers play a role in guiding children so that these skills can be enhanced along with their age and developmental stage. However, the application of problem-solving skills in learning activities has become a challenge for teachers to implement because there are no specific reference sources that can be used as a guide. This is also supported by the findings of a needs analysis where there is a need to develop a problem-solving framework that focuses on problem-solving steps using non-digital games. The problem-solving framework has been developed and needs to be evaluated for its usability in the usability evaluation phase using the Fuzzy Delphi Method. It aims to measure the usability and suitability of the non-digital game-based problem-solving framework that has been developed in the design and development phase. 25 preschool teachers were selected as experts to provide feedback through a questionnaire. The findings show that all experts in this phase agree that all main components, elements in the main components, and the priority flow for each element of the problem-solving framework have achieved an appropriate status and show a high consensus on the usability of the problem-solving framework that has been developed. Therefore, the problem-solving framework can be used by preschool teachers as a specific guide in implementing problem-solving activities using non-digital game

Nominal group technique application towards design of components and elements of non-digital game framework

Non-digital games are a tool that can help children to build and improve problem solving skills in early mathematics learning. Teachers need to design a learning activity using non-digital games taken account problem solving skills in the learning activities. However, the application of problem-solving skills in early mathematics learning activities is challenging, as there is no specific reference that can be used as a guide in implementing effective learning activities. The nominal group technique (NGT) approach is used to design the main components and elements of ProSkiND non-digital games framework based on the expert validation. A total of 12 experts were selected to validate the proposed main components and elements of the ProSkiND non-digital game using NGT online workshop. There were five main components with 41 elements were proposed: activity objective, teacher’s preparation, teacher’s role, children’s role, and activity evaluation. In this study, experts are asked to evaluate the ProSkiND non-digital games main components and elements based on the percentage value of agreement. The value of percentage of agreement that exceeds 70% (≥70%) is acceptable. The findings in this phase are used to develop main components and elements of the ProSkiND non-digital game framework based on problem solving skills for preschool early mathematics using the interpretive structural modelling (ISM) approach

A Review of Metal Injection Moulding on WC-Co Cemented Carbide Comprised of Grain Growth Inhibitors (GGI)

This paper aims to provide a summary of metal injection moulding technologies utilising cemented WC-Co carbides comprised of grain growth inhibitors (GGI). The advanced manufacturing of metal injection moulding (MIM) has the ability to produce cement nanostructured carbides. In addition, the nature of the feedstock plays a crucial role when manufacturing a defect-free component at each point of the MIM phase, thus the interactions between the metal powder and the binder combining, moulding, and debinding are important to be recognised. The primary objective of this analysis is to investigate the characterization of feedstock to form a homogenous mixture. There are five criteria to classify features of the feedstock which include powder characteristics, binder composition, powder content ratio, mixing cycle, and approaches to palletization. Not only that, the feedstock must meet specific criteria; higher powder loading with excellent flowability by the rheological approaches. The second goal of the research is to re-evaluate feedstock’s flow properties in relation to rheological activity in terms of index flow behaviour (n), activation energy (E), and mouldability (α). MIM practitioners have continued to underestimate erratic product quality, including inadequate regulation, distortion, and internal and external defects. These defects can arise in the early processing phases, but often occur only after sintering or debinding. The approaches are also challenging to provide. This chapter includes a description of MIM defects. Explanations are listed and recommendations are provided for these defects

Husband-Wife income sharing from al-Ma'ruf perspective / Azhar Abdul Aziz … [et al.]

Current scenario has indicated that the number of women going to work is increasing and cases of wives having more incomes than their husbands are common. This has led to a question of whose responsibility is the expenditure of a family, particularly when the husbands are having lesser incomes. The concept of income sharing between husband and wife is seen as a solution to the issue. This study attempted to examine the al-ma 'ruf concept of income sharing from the view of the scholars. The survey method was then adopted to examine the current practice of income sharing under the al-ma 'ruf concept. Finding of the study showed that a significant number of husbands neglect their responsibilities to bear the financial rights of the wives, thus non-complying the ma'ruf concept. The study proposed for the husbands to strive harder in fulfilling their responsibilities to finance the expenditure of the family

Fatigue behavior of kenaf fibre reinforced epoxy composites

Towards green material, fatigue life of epoxy and its unidirectional kenaf fibre reinforced epoxy composites were investigated. These specimens were hand lay-out made. The specimens were cycled to tension-tension fatigue loading at stress ratio of 0.5 and 5 Hz of frequency to determine the fatigue life and its life characteristic at given 5 stress levels. Fibre content ratios were found to affect fatigue life strongly on the low cycle fatigue regime as illustrated with stress level versus cycles to failure. It is found that kenaf fibre reinforced epoxy composites with higher fibre content posses higher load carrying capacity and degradation rates. The existing models developed by Mandell, Manson-Coffin and Hai-Tang were adopted to predict the fatigue life. Some of the models show minor similarities with the experimental data, but not universally applicable to predict the fatigue life when it comes with various amount of fibre volume

Wear properties of paste boronized 316 stainless steel before and after shot blasting process / Muhamad Hafizuddin Mohamad Basir, Bulan Abdullah and Siti Khadijah Alias

This research investigates and analyzes wear properties of 316 stainless steel before and after applying paste boronizing process and to investigate the effect of shot blasting process in enhancing boron dispersion into the steel. In order to enhance the boron dispersion into 316 stainless steel, surface deformation method by shot blasting process was deployed. Boronizing treatment was conducted using paste medium for 8 hours under two different temperatures which were 8500C and 9500C. Wear behaviour was evaluated using pin-on-disc test for abrasion properties. The analysis on microstructure, X-ray Diffraction (XRD) and density were also carried out before and after applying boronizing treatment. Boronizing process that had been carried out on 316 stainless steel increases the wear resistance of the steel compared to the unboronized 316 stainless steel. The effect of boronizing treatment together with the shot blasting process give a greater impact in increasing the wear resistance of 316 stainless steel. This is mainly because shot blasted samples initiated surface deformation that helped more boron dispersion due to dislocation of atom on the deformed surface. Increasing the boronizing temperature also increases the wear resistance of 316 stainless steel. In industrial application, the usage of the components that have been fabricated using the improved 316 stainless steel can be maximized because repair and replacement of the components can be reduced as a result of improved wear resistance of the 316 stainless steel

Toughening of ceramic shell mould with rice husk fiber (CSm-RH) to improve strength property and mould performance

For ages, ceramic shell mould (CSm) have been extensively applied in investment casting industry. The formation of CSm requires multiple steps of dipping, layering drying and firing stages. The later steps are very crucial as the solidification thin layer CSm that consist of loose ceramic particles easily cracks when exposed to the higher thermal effect. The inclusion of fiber or any reinforces phases is able to enhance fired ceramic body and also strengthen the green ceramic structure. Thus, the feasibility of rougher NaOH treated rice husk fiber (RHT) prior embedded into composited structure has shown a significant CSm improvement by induced a better adhesion properties and larger bonding area with brittle ceramic matrix, resulted in increased green strength (1.34 MPa) and fired body strength (4.32 MPa). Owing to the decomposed of lignin layer in CSm with untreated rice husk fiber (CSm-RHU) exhibited a higher porosity that provide a better permeation paths of air flow during molten metal pouring as increased 30 % from the standard CSm permeability, giving an enormous benefit for investment casting cooling process. Overall, the incorporation of RHT fiber in a CSm matrix of both green and fired body governed in toughening of brittle ceramic body, hence avoid failure to the casting mould

Effect of process parameters on the mechanical properties and failure behavior of spot welded low carbon steel

In this research, the effect of spot welding parameters on weld quality was investigated. The main affecting welding parameters such as weld current, weld time, electrode force and holding time were determined as the basis for quality evaluation. The selected quality features were classified into mechanical properties and failure behavior, which were required for application with highly dynamic loading. The peak load as one of the important mechanical properties, as well as the two distinct failure modes which were cross-nugget and complete button pull, were observed using tensile-shear stress. To obtain detailed shear stress testing results and to determine the significance of parameters, a servo-hydraulic testing machine was run at a constant cross-head speed of 2mm/min followed by statistical analysis methods, which were Taguchi’s L16 orthogonal array and Analysis of Variance (ANOVA). Furthermore, the failure mode was to be observed based on the fracture surface used as reference for acceptance or rejection of the weld joint. Based on the results, the weld current was the significant factor affecting shear stress and the complete button pull was mostly found, which leads to the satisfactory condition of the joint. Cross-nugget and full button pull-out were the dominant failures observed in the lap-shear test. The cross-nugget failure leads to a low shear load, while complete button pull-out displays maximum shear load

Optimisation of biodegradation conditions for waste canola oil by cold-adapted Rhodococcus sp. AQ5-07 from Antarctica

Background: The potential waste canola oil-degrading ability of the cold-adapted Antarctic bacterial strain Rhodococcus sp. AQ5-07 was evaluated. Globally, increasing waste from food industries generates serious anthropogenic environmental risks that can threaten terrestrial and aquatic organisms and communities. The removal of oils such as canola oil from the environment and wastewater using biological approaches is desirable as the thermal process of oil degradation is expensive and ineffective. Results: Rhodococcus sp. AQ5-07 was found to have high canola oil-degrading ability. Physico-cultural conditions influencing its activity were studied using one-factor-at-a-time (OFAT) and statistical optimisation approaches. Considerable degradation (78.60%) of 3% oil was achieved by this bacterium when incubated with 1.0 g/L ammonium sulphate, 0.3 g/L yeast extract, pH 7.5 and 10% inoculum at 10°C over a 72-h incubation period. Optimisation of the medium conditions using response surface methodology (RSM) resulted in a 9.01% increase in oil degradation (87.61%) when supplemented with 3.5% canola oil, 1.05 g/L ammonium sulphate, 0.28g/L yeast extract, pH 7.5 and 10% inoculum at 12.5°C over the same incubation period. The bacterium was able to tolerate an oil concentration of up to 4.0%, after which decreased bacterial growth and oil degradation were observed. Conclusions: These features make this strain worthy of examination for practical bioremediation of lipid-rich contaminated sites. This is the first report of any waste catering oil degradation by bacteria originating from Antarctica