19672 research outputs found
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Benchmarking developed property portfolio markets in Malaysian-listed property companies
No full textThis paper aims to benchmark the level of performance and volatility of Malaysian-Listed Property Companies (MLPCs) within developed countries over the period January 1994 to December 2014. This research seeks to analyse property portfolio investment performances as well as volatility levels using advanced empirical analyses such as the Autoregressive Conditional Heteroskedasticity (ARCH) family models. This research also assesses the dynamics of MLPCs during the recent Global Financial Crisis (GFC) within developed countries. The results indicate that MLPCs show poor performance compared to other developed countries. However, MLPCs were able to offer diversification potential in certain sub-periods. In terms of linkages within the markets, MLPCs do not show any relationship to the listed property companies (LPCs) in developed countries. In addition, MLPCs show high volatility over the study period compared to developed markets. Nevertheless, MLPCs were able to show a competitive advantage compared with LPCs in developed countries during the GFC. Based on the performance and volatility assessment, it clearly shows that the property portfolio market is still way behind compared to developed markets. Malaysia aims to be a developed country very soon; therefore, there is still a lot of work that needs to be done to reform the market to be more attractive
Ultrasonic technology for value added products from feather keratin
No full textFeather keratin is a biomass generated in excess from various livestock industries. With appropriate processing, it holds potential as a green source for degradable biopolymer that could potentially replace current fossil fuel based materials. Several processing methods have been developed, but the use of ultrasonication has not been explored. In this study, we focus on (i) comparing and optimizing the dissolution process of turkey feather keratin through sonication and conventional processes, and (ii) generating a biodegradable polymer material, as a value added product, from the dissolved keratin that could be used in packaging and other applications. Sonication of feather keratin in pure ionic liquids (ILs) and a mixture containing ILs and different co-solvents was conducted under different applied acoustic power levels. It was found that ultrasonic irradiation significantly improved the rate of dissolution of feather keratin as compared to the conventional method, from about 2 h to less than 20 min. The amount of ILs needed was also reduced by introducing a suitable co-solvent. The keratin was then regenerated, analyzed and characterized using various methods. This material holds the potential to be reused in various appliances
An analysis of occupants response to thermal discomfort in green and conventional buildings in Malaysia
No full textThe aim of this study is to examine what people do when they are too hot or too cold, and whether there are significant differences in the behaviour of occupants between green and conventional buildings. Case studies of green and conventional buildings were used in this study. Questionnaires were used as the tool to gain the relevant information from the building occupants of the case studies. Results showed that in response to feeling cold, three actions were significantly different between green and conventional buildings. One of the actions were on environmental adjustments (i.e. green building occupants were less likely to adjust the temperature system) and two were on personal adjustments (i.e. green building occupants less likely to put warmer clothes & less likely to alter timing of work pattern). While in response to feeling too hot, two actions were significantly different between the building types with one action from environmental adjustment (i.e. green building occupants less likely to adjust temperature system) and personal adjustment (i.e. green building occupants less likely to consume cold drinks/food). To date, there is limited understanding on whether green buildings have any different influences on how occupants behave in response to thermal discomfort. The findings in this study will aid designers to design better buildings that encourage better behaviour adaptations
AFM analysis of collagen fibrils in expanded scalp tissue after anisotropic tissue expansion
No full textSuccessful use of tissue expanders depends on the quality of expanded tissue. This study evaluates the impact of anisotropic self-inflating tissue expander (SITE) on the biomechanics of skin. Two different SITE were implanted subcutaneously on sheep scalps; SITE that requires 30 days for maximum expansion (Group A; n = 5), and SITE that requires 21 days for maximum expansion (Group B; n = 5). Control animals (n = 5) were maintained without SITE implantation. Young's Modulus, D-periodicity, overlap and gap region length, diameter, and height difference between overlap and gap regions on collagen fibrils were analyzed using atomic force microscopy. Histology showed no significant differences in dermal thickness between control and expanded skin of groups A and B. Furthermore, most parameters of expanded skin were similar to controls (p > 0.05). However, the height difference between overlap and gap regions was significantly smaller in group B compared to both control and group A (p < 0.01). Strong correlation was observed between Young's Modulus of overlap and gap regions of the control and group A, but not group B. Results suggest that a relatively slower SITE can be useful in reconstructive surgery to maintain the biomechanical properties of expanded skin
Effective removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- from landfill leachate using locust bean gum
No full textThe widespread distribution of persistent organic pollutants (POPs) in landfill leachate is problematic due to their acute toxicity, carcinogenicity and genotoxicity effects, which could be detrimental to public health and ecological systems. The objective of this study was to evaluate the effective removal of POPs – namely, p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- – from landfill leachate using locust bean gum (LBG), and in comparison with commonly used alum. The response surface methodology coupled with a Box–Behnken design was employed to optimize the operating factors for optimal POPs removal. A quadratic polynomial model was fitted into the data with the R2 values of 0.97 and 0.96 for the removal of p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl), (S)-, respectively. The physicochemical characteristics of the flocs produced by LBG and alum were evaluated with Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The infrared spectra of LBG-treated floc were identical with LBG powder, but there was some variation in the peaks of the functional groups, signifying the chemical interactions between flocculants and pollutant particles resulting from POPs removal. The results showed that p-tert-Butylphenol and Pyridine, 3-(1-methyl-2-pyrrolidinyl)-, (S)- obtained 96% and 100% removal using 500 mg/L of LBG at pH 4. pH have a significant effect on POPs removal in leachate. It is estimated that treating one million gallons of leachate using alum (at 1 g/L dosage) would cost US2. LBG is eco-friendly, biodegradable and non-toxic and, hence, strongly recommended as an alternative to inorganic coagulants for the treatment of POPs in landfill leachate
Growth kinetics and biodeterioration of polypropylene microplastics by Bacillus sp. and Rhodococcus sp. isolated from mangrove sediment
No full textInterest in the biodegradation of microplastics is due to their ubiquitous distribution, availability, high persistence in the environment and deleterious impact on marine biota. The present study evaluates the growth response and mechanism of polypropylene (PP) degradation by Bacillus sp. strain 27 and Rhodococcus sp. strain 36 isolated from mangrove sediments upon exposure to PP microplastics. Both bacteria strains were able to utilise PP microplastic for growth as confirmed by the reduction of the polymer mass. The weight loss was 6.4% by Rhodococcus sp. strain 36 and 4.0% by Bacillus sp. strain 27 after 40 days of incubation. PP biodegradation was further confirmed using Fourier-transform infrared spectroscopy and scanning electron microscopy analyses, which revealed structural and morphological changes in the PP microplastics with microbial treatment. These analyses showed that the isolates can colonise, modify and utilise PP microplastics as carbon source
Effects of Process Parameters on the Surface Roughness of Stainless Steel 316L Parts Produced by Selective Laser Melting
No full textSelective Laser Melting (SLM) is an additive manufacturing method that is used to fabricate different types of complex components using a layer-by-layer approach. The parts are produced directly from three-dimensional computer-aided design data by melting the powdered material layer-by-layer with the aid of laser power. In this work, an experimental investigation of the process parameters of the SLM method using stainless steel 316L powder was conducted. The influence of laser power, scanning speed, and hatching distance on the surface roughness of the specimens was investigated. The design of experiment was conducted using Taguchi’s L16 orthogonal array. Furthermore, statistical analysis using signal-to-noise (S/N) response and analysis of variance (ANOVA) was used to obtain the optimal parameter combinations of the SLM process. From the experimental results, it was found that laser power has the greatest effect on the surface roughness relative to scanning speed and hatching distance. Moreover, using regression analysis, the predicted values of surface roughness and signal-to-noise ratios were obtained. The predicted values were then compared with the experimental values. Lastly, shot peening technique was used to improve the surface roughness of the manufactured components. The results show that the shot peening process offers about 33.28 % reduction in the surface roughness of the manufactured parts
Synthesis of gold nanoparticles stabilized by a pyrazinium thioacetate ligand: A new colorimetric nanosensor for detection of heavy metal Pd(II)
No full textWe developed a facile method for the synthesis of Gold nanoparticles (AuNPs) stabilized by cationic 1-(3-(acetylthio)propyl)pyrazin-1-ium ligand denoted as APP. Gold nanoparticles stabilized by APP (APP-AuNPs) are found to be polydispersed in size and lie in the range of 5–10 nm. We report a robust and sensitive protocol for the detection of heavy toxic metal ion Pd(II) in water using APP-AuNPs. From the fifteen salts tested, APP-AuNPs demonstrated a sensitive and selective spectrophotometric signal, as well as naked eye indication for recognition of Pd(II) ions. Pd(II) ions caused a colorimetric, distinguished response to APP-AuNPs based on the aggregation induced decrease of surface plasmon resonance (SPR) band. The nanosensor probe displayed a sensitive response to the Pd(II) ions in a wide range of concentration and pH, with detection limit of as low as 4.23 μM. Furthermore, the decrease in SPR band of APP-AuNPs due to Pd(II) ions was unaffected by tap water samples and/or human blood plasma
A thresholding method based on interval-valued intuitionistic fuzzy sets: an application to image segmentation
No full textThis paper proposes a new fuzzy approach for the segmentation of images. L-interval-valued intuitionistic fuzzy sets (IVIFSs) are constructed from two L-fuzzy sets that corresponds to the foreground (object) and the background of an image. Here, L denotes the number of gray levels in the image. The length of the membership interval of IVIFS quantifies the influence of the ignorance in the construction of the membership function. Threshold for an image is chosen by finding an IVIFS with least entropy. Contributions also include a comparative study with ten other image segmentation techniques. The results obtained by each method have been systematically evaluated using well-known measures for judging the segmentation quality. The proposed method has globally shown better results in all these segmentation quality measures. Experiments also show that the results acquired from the proposed method are highly correlated to the ground truth images
Bone-borne accelerated sutural expansion: A microcomputed tomography study in rabbits
No full textIntroduction: In this study, we evaluated the effect of bone-borne accelerated expansion protocols on sutural separation and sutural bone modeling using a microcomputed tomography system. We also determined the optimum instant sutural expansion possible without disruption of bone modeling. Methods: Sixteen New Zealand white rabbits, 20 to 24 weeks old, were randomly divided into 4 experimental groups. Modified hyrax expanders were placed across their interfrontal sutures and secured with miniscrew implants located bilaterally in the frontal bone. The hyrax appliances were activated as follows: group 1 (control), 0.5-mm per day expansion for 12 days; group 2, 1-mm instant expansion followed by 0.5 mm per day for 10 days; group 3, 2.5-mm instant expansion followed by 0.5 mm per day for 7 days, and group 4, 4-mm instant expansion followed by 0.5 mm per day for 4 days. After 6 weeks of retention, sutural separation and sutural bone modeling were assessed by microcomputed tomography and quantified. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests and the Spearman rho correlation (P <0.05). Results: Median amounts of sutural separation ranged from 2.84 to 4.41 mm for groups 1 and 4, respectively. Median bone volume fraction ranged from 59.96% to 69.15% for groups 4 and 3, respectively. A significant correlation (r = 0.970; P <0.01) was observed between the amounts of instant expansion and sutural separation. Conclusions: Pending histologic verifications, our findings suggest that the protocol involving 2.5 mm of instant expansion followed by 0.5 mm per day for 7 days is optimal for accelerated sutural expansion. When 4 mm of instant expansion was used, the sutural bone volume fraction was decreased