Formation of Cr23C6 During the Sensitization of AISI 304 Stainless Steel and its Effect to Pitting Corrosion

The metallic carbide precipitation was observed after the sensitization of AISI 304 stainless steel specimens in neutral flame by using oxy-fuel and slowly cooled in the air. Correlation between corrosion and X-Ray Diffraction (XRD) shows that the enrichment of Cr23C6 in the microstructure of AISI 304 worsens the pitting corrosion resistance properties as the sensitization time increases from 5 to 60 s. However, the precipitation dissolved and corrosion resistance properties improved after the specimens treated in solution quenching treatment at 1130 oC, soaked from 24 – 120 min, then rapidly cooled in water

Effect of nano- and micro- reinforced agents on dry sliding wear of polyester composites

Dry sliding wear of polyester hybrid composites containing carboxylic functionalized multi-walled carbon nanotubes (CNT) and microparticles, silica (SiO2) was studied at different sliding distances. An attempt has been made to produce uniform dispersion of nano- and micro- particles in the test samples by ultrasonication. The tribological properties of the hybrid composites were performed by using pin-on-disc (POD) tester against grey cast iron countersurface. The dry sliding wear tests were carried out under pressure-velocity (pv) condition of 0.4 MPa and 4 m/s for total sliding distance of 28800 m and at an interval of every sliding distance of 3600 m, wear properties and behavior were studied. The samples containing 10 wt.% silica (microparticles) with and without CNT always show increase in coefficient of friction at the expense of wear rate. However, samples containing only CNT have the lowest wear rate with the increase in coefficient of friction. Sliding distance studies also provide the information on wear rates which were ever changing at different sliding distances whereas average coefficient of friction did not vary throughout the tests. SEM observations of wear surfaces showed different wear morphologies when reinforcement (CNT or SiO2) incorporated into the composites either alone or in combination

Effect of Process Temperature and Time on the Properties of Microwave Plasma Nitrided Ti6Al4V alloy

Titanium alloy (e.g. Ti-6Al-4V) has an excellent combination of properties. However in many cases, the application is limited because of the poor wear property. In this work, a surface modification (plasma nitriding) is carried out to improve the surface properties of Ti-6Al-4V, as a treatment prior to a hardcoating deposition, leading to a duplex coating system. This is an effort to improve the surface and near surface property of Ti-6Al-4V. Plasma nitriding is performed utilizing microwave plasma method in 25% Ar- 75% N2 atmosphere at temperatures of 600°C and 700°C for different processing times (1, 3 and 5 hours). The phase and microstructure of plasma nitrided substrate were characterized by using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The plasma nitrided Ti-6Al-4V properties (surface roughness, surface hardness and case depth) were determined using profilometer and microhardness, respectively. Results obtained showed a significant increase on the surface hardness of Ti-6Al-4V. This is due to the formation of TiN and Ti2N phases in the form of compound layer. Besides, it shows that the diffusion of nitrogen into the Ti-6Al-4V substrate produces case depth up to 130 μm and this contributes to the improvement of the near surface hardness due to the changes in the microstructures. It was also found that the surface hardness and surface roughness increased with the increases in the process temperature and times

Effect of Nitriding Temperature and Nitriding Time on MgAZ91D Alloy / Wan Amirul Shafiz Wan Zulkifli...[et al.]

Magnesium and its alloys are widely applied in the automotive industries, electronic and telecommunication industries due to its low densities and excellent strength to the weight ratio. However, it possesses a low surface hardness which can weaken the adhesion properties, especially when hard coating is applied. The need of hard coating is crucial to enhance its corrosion resistance. In this work, nitriding process was carried out to modify the surface properties of MgAZ91D in enhancing its corrosion resistance. The nitriding process was conducted using a high-temperature furnace with the nitrogen gas flow at a constant rate of 5scfh. Three nitriding temperatures were set which were at 300°C, 400°C, and 500°C, for a nitriding period of 1 and 2 hours respectively. Analysis on the surface roughness of the nitrided MgAZ91D was then conducted using MitutoyoSJ410 profilometer. Surface hardness and case depth of the nitride MgAZ91D was analyzed using MitutoyoVicker’s microhardness testing machine. The results showed that the surface hardness, surface roughness, grain size and the case depth of the nitrided MgAZ91D increased through the increase as the process temperature and time. However, the effect of grain size on the case depth hardness is not significant. Thus, the process temperature and time of nitriding MgAZ91D is crucial to be investigated to obtain the right combinations between the surface hardness, surface roughness and case depth for corrosion applications

Implementation Of Cooperative Problem–Based Learning In Achieving Learning Outcomes

Material Selection is one of the program core subjects introduced in Bachelor of Engineering in Manufacturing Engineering. Five learning outcomes have been outlined in the subject. In order to achieve the learning outcomes, the subject delivery involves implementing Cooperative Problem-Based Learning (CPBL) activities as a part of teaching and learning process. Generally, the summative assessment involves cognitive domain and soft skill. This is an improved approach in teaching and learning process as compared to the common practice. For each learning outcome, a specific learning domain and taxonomy level were defined and rubrics for assessment were developed accordingly. Constructive alignment among the learning outcomes, delivery methods, assessment and evaluation gives an overall reflection on the students’ Iearning outcomes attainment. Students' ac1tievement is evaluated based on Key Performance Index set by the Faculty. Students' reflection in the subject matters and teaching and learning process provides essential inputs in outlining a few strategies for Continuous Quality lmprovement purpose. It was observed that Cooperative Problem-Based Learning activities arc able to promote student-centered learning culture among the students. It also nurtures students to be graduates who fulfill the criteria outlined in the Program Outcomes

Effects of Air Intake Pressure on the Engine Performance, Fuel Economy and Exhaust Emissions of A Small Gasoline Engine

This study presents the engine performance, fuel economy and exhaust emissions at variations of air intake pressure. In a carburetor system, the air intake pressure is influenced by the degree of opening throttle plate and the Venturi effect which draws the fuel to the combustion chamber. The experimental work was carried out on variations of engine speed and load using a single cylinder four stroke gasoline engine attached to a dynamometer. The measured exhaust emission compositions are used to determine the mode of combustion. The results show that the standard air intake system resulted in rich combustion which then led to incomplete combustion, which was caused by less availability of air for the combustion process. Eliminating the air filter reduces the air flow restriction in the air intake system resulting in better combustion and less unburned components due to higher air availability. Higher air intake pressure is better at increasing the efficiency of combustion within a limited time to improve fuel economy, power output and exhaust emissions. Better combustion also leads to reduced unburned components such as carbon (C), hydrogen (H2), carbon monoxide (CO) and hydroxide (OH), which results in cleaner emissions

The necessity of equal protection between employer and employee in the duty of fidelity pertaining to confidential information: a comparative analysis / Muhammad Iqram Zulkifli … [et al.]

Currently the enforcement regarding the law that govern duties between employer and employee is still vague. The vagueness of the law remains an issue as it lead to an unequal protection offered toward both parties which are employer and employee. The conflict can be seen when the employer is unclear to what extent their interest can be guarded and the dilemma of the ex employer to advance their future after the post employment period without being accuse to use their ex employer's confidential information. It can thus be concluded that the sufficiency of implied term in common law pertaining to the duty of fidelity in term of confidential information between employer and employee needed to be review. This study will examine on the sufficiency of the protection pertaining to the duty of good faith and fidelity in terms of confidential information between employer and employee. This study also is to show that there are necessity of equal protecting amongst the employer and employee in this pertaining matter. One of the objectives of this research is to assist the policy maker to draw up a legal framework that could provide the balance in protecting the interest of employer as well as employee with regards to confidential information. In this proposed research, the purpose is to explore the usual practices of employers and employees on the duty of fidelity pertaining to confidential information in the public and private sector through the utilisation of the qualitative research method. The primary sources used in this research are mainly statutes, subsidiary legislations, regulatory frameworks and cases in Malaysia, Singapore, Hong Kong and the United Kingdom. This particular research will run through a comparative analysis by comparing with other jurisdiction where the duty of fidelity pertaining to confidential information which applies on United Kingdom, Singapore and Hong Kong. This research shall help in highlighting the existing laws, the frameworks and the lacunae in the respective jurisdictions such as Malaysia, Singapore, Hong Kong and United Kingdom in order to provide a definite guideline as to develop the law in Malaysia and to promote better practice of the enforcement of the law and work between the employers and employees. This significance of this research will provide suggestions and recommendations, which might be used as a reference to assist the Parliament in enacting better law for the betterment of the public at large. Confidential information plays a very vital role in the survival of an organization and institution. Nevertheless, the falling of this kind of information to the wrong hands shall lead to implications that are detriment to the employer's business. Meanwhile, in the context of confidential information, the duty of fidelity requires that an employee must not use information obtained in the course of their employment to the detriment of the employer's business. However, no such definite framework that governs on what shall be confidential and what is only a mere information. This is because employers tend to overrate the information that they have and restrain the employees from using it, even after they leave the course of employment. Thus, it can be concluded that these are the reasons why there shall be an analysis on the problems and the challenges of protecting the confidential information, be it either in the public or the private sector which will be discussed in the entire chapters of this research

Intermediate Phases Formed During Synthesis Of β-Tricalcium Phosphate Via Wet Precipitation And Hydrothermal Methods

Beta-tricalcium phosphate (β-TCP) was synthesized using an aqueous wet precipitation method as well as a hydrothermal method. The processing parameters adopted in both methods were maintained to be as similar as possible. The precursor materials reacted in both methods were 0.3 mole of phosphoric acid, H3PO4, and 0.45 mole of calcium hydroxide, Ca(OH)2. The available processing parameters for the precipitation method are much more varied whilst the parameters for the hydrothermal method are much more limited. Hence, the parameters chosen were based on the availability of the parameters to accommodate both methods, viz. the use of the same precursor materials in a stoichiometric ratio of 1.5, a reaction temperature of 70°C, a reaction time of 2 hours, a stirring speed of either 200 or100 rpm, and a stirring duration of 2 hours. The intermediate phases formed upon precipitation were compared. It was confirmed by x–ray diffraction that the powder formed from the precipitation method was monetite and hydroxyapatite, whilst the initial the powder formed from the hydrothermal method consisted of brushite and hydroxyapatite. Thermal analysis was performed on both powders to ascertain the best heat-treatment temperature. Both powders were subsequently subjected to a heat-treatment temperature of 900°C and both were confirmed by x-ray diffraction to be single-phase β-tricalcium phosphate. Scanning electron microscopy was performed on both heat-treated powders and the microstructures observed were found to be distinctly different. The precipitated powder consisted of nano-sized powders that were heavily agglomerated, whilst the hydrothermal powder consisted of a flattened microstructure due to the pressure imposed upon reaction

Assessment of knowledge, attitude and practice among house officers in UKM Medical Centre on needle stick injuries

Needle stick injury is one of the most serious occupational hazards among house officers in which it may lead to possible severe consequences such as HIV, Hepatitis B, and C infection. The aim of the study was to explore and compare the knowledge, attitude and practice (KAP) among house officers of UKM Medical Centre (UKMMC) regarding needle stick injury. A cross-sectional study was conducted with the total of 151 self-administered questionnaires from house officers in UKMMC within the period of five months. The data was collected via universal sampling method. Components evaluated were prevalence, demographic data and scores on KAP concerning needle stick injury among house officers. Out of the 151 house officers recruited for the study, 34.9% of them had a history of needle stick injury during their practice, with 6.7% of the injury that occurred in their current posting department. There was a significant association (p<0.05) between history of needle stick injury and the practice of house officers (p=0.035). House officers with a history of needle stick injury had a lower mean score of practice (8.65 ± 2.00) compared to those without history (9.40 ± 1.09). This study also demonstrated that there were significant correlations between Knowledge-Practice (r=0.194, p=0.018) and Attitude-Practice (r=0.182, p=0.026) of UKMMC house officers. These findings demonstrated that a good level of knowledge and attitude results in better practice of house officers hence reducing the incidence of needle stick injury. Therefore, suitable health education programs with regards to needle stick injury and preventive measures should be intensively implemented on all house officers prior to and during their practice

Experimental investigation on the influence of temperature on the adsorption of henna extract on koalinite in reducing surfactant adsorption

The adsorption ability of henna extract as an environment-friendly and easily available sacrificial agent was investigated. Fourier transform infrared-attenuated total reflectance (FTIR-ATR) was used to characterized henna extract and kaolinite. The adsorption of henna extract on kaolinite was done using Ultraviolet-visible spectroscopy (UV-Vis). The influence of temperature on the henna extract adsorption on kaolinite was studied. The mechanisms of the adsorption process were interpreted. Also, henna extract performances in reducing the adsorption of surfactant were assessed. The outcome shows that henna extract adsorption on kaolinite was decreased with increasing temperature. The adsorption value decreased from 7.88 to 7.04 mg/g from the temperature of 25oC to 75oC due to the increased of the kinetic energies of the henna extract molecules. A reduction of 38% of surfactant adsorption was observed and showed a profound drop in the adsorption of surfactant in the presence of henna extract suggesting a possibility to be utilized as a sacrificial agent in reducing the adsorption of surfactant