National University of Malaysia

About: National University of Malaysia is a education organization based out in Kuala Lumpur, Malaysia. It is known for research contribution in the topics: Population & Heat transfer. The organization has 26593 authors who have published 41270 publications receiving 552683 citations. The organization is also known as: NUM & Universiti Kebangsaan Malaysia.

Cement-based solidification for the safe disposal of blasted copper slag

Abstract: This paper describes an investigation of cement-based solidification/stabilization process for the safe disposal of blasted copper slag. The treatments evaluated were based on ordinary Portland cement (OPC). Mortar specimens with ground copper slag ranging from 0% to 10% by weight of cement were tested for whole block and crushed block leachability, compressive strength and hydration. The results indicated that the leaching of selected heavy metal ions from the cement matrix was low and did not exceed the Malaysian Environmental Quality Act. Addition of copper slag to cement increased initial and final setting times. The primary hydration process was the OPC hydration. The strength of the copper slag mortar was generally lower than that of the control mortar and the amount of ground copper slag to replace cement for optimum strength was about 5%.

An environment-friendly solution for indoor air purification by using renewable photocatalysts in concrete: A review

Abstract: Photocatalyst is needed for cleaner environment and a better quality of life. This fact leads an idea of more eco-compatible use of light. This approach could become an integral component of strategies to reduce indoor air pollutants through the use of photocatalysts as construction materials. In this study, we discuss the quality of indoor air, sources of pollutants in the indoor environment, and the photocatalysis process. Moreover, the different parameters and uses of different photocatalysts in concrete for indoor air purification, starting from the early research until the current research, are described, and the reaction mechanism of photocatalytic oxidation and sustainable construction by using photocatalysts are also reviewed.

Composition of selected heavy metals in road dust from Kuala Lumpur city centre

Abstract: This study was carried out in order to determine the concentration of heavy metals, e.g., lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), nickel (Ni) and chromium (Cr) in road dust in Kuala Lumpur’s city centre. Samples were collected from four sampling locations, each of which had four sampling points and three replications. Heavy metals from different fractions of particles separated by different diameter sizes: d Mn > Zn > Pb > Ni > Cr > Cd. The fact that Cd had the highest enrichment factor value (EF) for all particle sizes indicates that anthropogenic activities contributed to the presence of this metal. There was also a higher EF value for heavy metals in small particle (Fraction A), compared to Fraction B and C, which suggests that fine particles were being produced through anthropogenic activities. Cluster analysis and principal component analysis demonstrated the likelihood of the heavy metals detected in the road dust, originating from road traffic and industrial activities.

Novel Corrosion Inhibitor for Mild Steel in HCl

Abstract: Corrosion inhibitory effects of new synthesized compound namely 5,5'- ((1Z,1'Z)-(1,4-phenylenebis(methanylylidene))bis(azanylylidene))bis(1,3,4-thiadiazole-2-thiol) (PBB) on mild steel in 1.0 M HCl was investigated at different temperatures using open circuit potential (OCP), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results showed that PBB inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiencies increased with the concentration of inhibitor, but decreased proportionally with temperature. Changes in impedance parameters suggested the adsorption of PBB on the mild steel surface, leading to the formation of protective films.

Construction waste minimisation comparing conventional and precast construction (Mixed System and IBS) methods in high-rise buildings: A Malaysia case study

Abstract: The construction industry has always been a major generator of construction waste and is often faced with the issue of its effective management in minimising environmental pollution. This research paper focuses on the construction waste generated from the construction of high rise buildings using 3 construction methods; Conventional Construction (Category I), the Mixed System (Category II) and Industrialised Building System (IBS, Category III). The construction waste for each construction category were characterised into its mineral and non-mineral components. The construction waste usage efficiency (CWUE), waste generation, reuse and recycling rates were also calculated. The IBS (Category III) was found to be the most efficient construction method with a waste generation rate (WGR) of 0.016 tons of construction waste/m 2 floor space compared to the Mixed System (Category II) at 0.030 tons/m 2 and the Conventional Construction (Category I) at 0.048 tons/m 2 . The construction waste usage efficiency (CWUE) was the highest in Category III (IBS) at 94.1% with only 5.9% of the total construction waste in this category being disposed at landfills. The Construction Industry Development Board (CIDB) of Malaysia has recognised its benefits and has actively promoted the use of IBS in Malaysia. The waste characterisation data and its uses (reuse and recycling) obtained from this study could be used as baseline data to promote and encourage the Malaysian construction industry to adopt the use of precast technology, the Industrialised Building System (Category III) and move away from the more traditional resource hungry Conventional Construction (Category I). The inclusion of the Mixed System (Category II) in this study as an intermediate construction method was aimed at providing the link between the Conventional Construction (Category I) and the IBS (Category III). The Mixed System (Category II) incorporates both the IBS and Conventional Construction methods. The Conventional Construction (Category I) with the incorporation of new construction technologies could easily be reclassified as the Mixed System (Category II), allowing Malaysian contractors to easily adopt it. This paves the way for better understanding for the use of precast technology which eventually would result in a positive shift towards the use of the IBS (Category III) by Malaysian contractors in the future. Thus, improving the construction industry's environmental performance and commitment to sustainable development as outlined by the CIDB's Construction Industry Master Plan 2006–2015 for Malaysia.