Norashikin Kamarudin

Synthesis and Battery Studies of Sodium Cobalt Oxides, NaCoO2 Cathodes

Sodium based batteries presented a new and promising battery system. This work attempted to develop NaCoO2 material using a new sol-gel method. The characterization of this sodium based material was done by using Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). Cyclic voltammetry showed that the material exhibit reversible oxidation and reduction peaks which meant that a sodium based battery was possible for this material. Electrochemical charge-discharge profile was performed to study the voltage plateaus exhibited by the material. It showed discharge plateaus of between 3.2 to 2.3 V and another plateau at 0.6 V.

Band Gap Energies of Magnesium Oxide Nanomaterials Synthesized by the Sol-Gel Method

In this work, the band gap energies of magnesium oxide (MgO) were investigated to see if calcination time affects the band gap energies of the MgO. MgO nanomaterials have been prepared by a sol-gel method. MgO precursors produced were calcined at a temperature of 600 °C for 24 hours and 48 hours. The structural characterization of samples is achieved using X-Ray Diffraction (XRD) and the morphology as well as particle size of MgO were examined by Field Emission Scanning Electron Microscopy (FESEM). UV-Vis NIR spectroscopy was used to determine the band gap energies of the materials. From the results, the band gap energy of the MgO with a longer heating time exhibited a higher value.

Optical Band Gap Energies of Magnesium Oxide (MgO) Thin Film and Spherical Nanostructures

Magnesium oxide (MgO) is one of the metal oxides which has unique properties and has great potential applications in industry. In this work, MgO was synthesized by using a sol‐gel and solid state methods. The precursor of MgO was annealed at the temperature of 600 °C for 1 hour and 800 °C for 24 hours for sol‐gel method. For solid state method, magnesium acetate was annealed at the temperature of 800 °C for 24 hours. These samples were characterized by using X‐Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). TEM micrographs show the morphology of the samples of the sol‐gel method are thin film nanostructures whereas sample of the solid state method is spherical shape. The band gap energies of the samples were measured using UV‐Vis NIR Spectrophotometer. The band gap values of the samples were calculated and it was found that there is a difference of band gap energies between samples employing different synthesis route.

Audit exemption among SMEs in Malaysia

Purpose - Audit helps both shareholders and stakeholders to make informed decisions about future directions, based on how the company is performing. The issue of audit exemption among small companies has been addressed in studies in the UK, Australia and Singapore, together with several others, while Malaysia still legally obligates all companies, irrespective of their size, to be audited annually. The purpose of this exploratory study is to explore the factors associated with a push for audit exemption among small to medium-sized enterprises (SMEs) in Malaysia. Design/methodology/approach - A survey of SMEs in Malaysias Klang Valley is conducted to examine their perceptions of audit value, audit burden and audit costs, and their implications for the acceptance of the current audit provisions. Findings - After follow-ups the survey yields a response rate of 83 percent, with 360 valid responses received. The results indicate that all three factors have a significant relationship with the level of acceptance of audit exemption. Their preferred audit exemption threshold is also presented. Research limitations/implications - The results from this study provide useful information for policy makers, auditors and directors of small companies in regards to audit exemption. Originality/value - The results of the study provide new information for policy makers, auditors and directors of small companies, with implications for future regulation on audit exemption.

Issues, challenges and the way forward for charitable organizations in Malaysia

This paper discusses the issues concerning ethics, governance and regulatory systems of charitable organizations in Malaysia, highlights the key challenges in managing the organizations, and suggests a better approach that needs to be adopted by the charitable organizations in Malaysia to eradicate the bad practices that can lead to fraud and mismanagement.

The electrical conductivities of polyimide and polyimide/Li triflate composites: An a.c. impedance study

Polymer electrolytes have been an essential area of research for many decades. One of the reasons was the need to find new electrolyte materials suitable for device applications like solid-state batteries, supercapacitors, fuel cells, etc. with enhanced characteristics. For more than 40 years, polyimide has been known as a super-engineering plastic due to its excellent thermal stability (Tg > 250 °C) and mechanical properties. Therefore, in an effort to develop new polymer electrolytes, polyimide as a polymer matrix was chosen. Composite films of the polymer doped with lithium salt, LiCF3SO3 was prepared. These PI based polymer electrolyte films were investigated by the alternating current (a.c.) impedance spectroscopy method in the temperature range from 300 K to 373 K. It was observed that conductivity increased with the increase of temperature and amount of doping salt. Alternatively, the activation energy (Ea) of the composite films decreased with the increase of the doping salt, LiCF3SO3.Polymer electrolytes have been an essential area of research for many decades. One of the reasons was the need to find new electrolyte materials suitable for device applications like solid-state batteries, supercapacitors, fuel cells, etc. with enhanced characteristics. For more than 40 years, polyimide has been known as a super-engineering plastic due to its excellent thermal stability (Tg > 250 °C) and mechanical properties. Therefore, in an effort to develop new polymer electrolytes, polyimide as a polymer matrix was chosen. Composite films of the polymer doped with lithium salt, LiCF3SO3 was prepared. These PI based polymer electrolyte films were investigated by the alternating current (a.c.) impedance spectroscopy method in the temperature range from 300 K to 373 K. It was observed that conductivity increased with the increase of temperature and amount of doping salt. Alternatively, the activation energy (Ea) of the composite films decreased with the increase of the doping salt, LiCF3SO3.

MgO Nanostructured Materials Obtained Via the Solid-State Reaction Method

Recently, several synthesis methods have been reported for producing magnesium oxide (MgO) nanostructures such as sol-gel, combustion, thermal evaporation, chemical precipitation, etc. This work describes a simple method to synthesize MgO nanostructures via a conventional solid-state reaction method using magnesium acetate tetrahydrate as a starting material. Magnesium acetate tetrahydrate was directly annealed at a temperature of 600 °C and 800 °C for 24 h. The X-Ray Diffraction (XRD) revealed that the annealed samples were pure while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) showed different morphologies of MgO. From the results, it is found that TEM may reveal information that cannot be observed in the SEM micrographs.

Effect of Synthesis Method on the Nanostructures of Magnesium Oxide (MgO) and their Band Gap Energies

Magnesium oxide (MgO) is a metal oxide which has many applications in industry and can be synthesized by many different synthesis methods. In this study, MgO was synthesized by using two different methods which were sol-gel and solid-state reaction methods. Both samples were annealed at 800 oC for 24 hours and characterized by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The band gap energies for both samples were determined by using UV-Vis NIR Spectroscopy. The band gap values of the samples are evaluated from the data. It was found that the band gap energies of the MgO using different synthesis route were not the same.

Synthesis and Electrochemical Behaviour of Lithium Manganese Vanadates

Lithium manganese vanadates are synthesized using the sol-gel method. The sol-gel method is a better synthesis method compared to that of the solid state reaction method and usually yields purer and more uniform sized particles. It also uses lower sintering temperatures and shorter time. This will be a savings in terms of costs of the material as heating requires a lot of electrical energy. Precursor materials acquired are subjected to thermal studies and a suitable sintering temperature is chosen in order to achieve pure, single phase compounds. As is well known it is not easy to get pure single phase final products for materials containing vanadium and manganese. From X-Ray diffraction (XRD), the results showed multi phase spinel lithium manganese vanadates. Battery fabrication is done using a composite cathode and a half cell is assembled in an argon filled glove box. Cell testing is done using a constant current charge-discharge procedure. The results show reasonable charge-discharge behaviour but the capacity is a little less than that for LiMn2O4.