22 research outputs found

    A proposed simulation optimization model framework for emergency department problems in public hospital

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    The Emergency Department (ED) is a very complex system with limited resources to support increase in demand.ED services are considered as good quality if they can meet the patient’s expectation.Long waiting times and length of stay is always the main problem faced by the management.The management of ED should give greater emphasis on their capacity of resources in order to increase the quality of services, which conforms to patient satisfaction.This paper is a review of work in progress of a study being conducted in a government hospital in Selangor, Malaysia.This paper proposed a simulation optimization model framework which is used to study ED operations and problems as well as to find an optimal solution to the problems. The integration of simulation and optimization is hoped can assist management in decision making process regarding their resource capacity planning in order to improve current and future ED operations

    Gold nanoparticle-decorated reduced-graphene oxide targeting anti hepatitis B virus core antigen

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    Hepatitis B virus core antigen (HBcAg) is the major structural protein of hepatitis B virus (HBV). The presence of anti-HBcAg antibody in a blood serum indicates that a person has been exposed to HBV. This study demonstrated that the immobilization of HBcAg onto the gold nanoparticles-decorated reduced graphene oxide (rGO-en-AuNPs) nanocomposite could be used as an antigen-functionalized surface to sense the presence of anti-HBcAg. The modified rGO-en-AuNPs/HBcAg was then allowed to undergo impedimetric detection of anti-HBcAg with anti-estradiol antibody and bovine serum albumin as the interferences. Upon successful detection of anti-HBcAg in spiked buffer samples, impedimetric detection of the antibody was then further carried out in spiked human serum samples. The electrochemical response showed a linear relationship between electron transfer resistance and the concentration of anti-HBcAg ranging from 3.91 ng mL−1 to 125.00 ng mL−1 with lowest limit of detection (LOD) of 3.80 ng mL−1 at 3 σ m−1. This established method exhibits potential as a fast and convenient way to detect anti-HBcAg

    Ce anomaly in I‒type granitic soil from Kuantan, Peninsular Malaysia: retention of zircon in the weathering product

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    This paper describes the Ce anomaly observed in granitic soil from the humid, tropical area of Kuantan, Pahang, Peninsular Malaysia. Three granite rock soil profiles from Kuantan, were sampled and all samples were analysed for rare earth elements. All the profiles of the granitic soil samples show prominent positive Ce anomalies, with the Ce/Ce* ratio values (Ce/Ce*= CeN/√LaN.PrN) ranging from 1.2 to 125. l. Ce4+ is compatible in zircon because it has also the same charge and a similar ionic radius as to Zr4+ (Ce4+ = 0.97 Å; Zr4+ = 0.84 Å). The retention of zircon in the weathering product of the granitic rocks will increase the Ce content in the soil. Thus it is likely that the positive Ce anomaly in the REE profile of the Kuantan Granites may also have resulted from retention of zircon in the weathering product

    Fault detection in three phase induction motor using artificial intelligence

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    Artificial intellegence (AI) techniques have proved their ability in detection of incipient faults in electrical machines. in this project, the fault diagnosis of three phase induction motors is studied detailed in unbalance voltage and stator inter turn fault using simulation models and neural networks have been used to train the data using Radial Basis Function Neural Network (RBFNN) in MATLAB with Graphical USer Interface Development Environment (GUIDE) structured

    Transport and retention behavior of carbonaceous colloids in natural aqueous medium: Impact of water chemistry

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    Carbon based materials are emerging as a sustainable alternative to their metal-oxide counterparts. However, their transport behavior under natural aqueous environment is poorly understood. This study investigated the transport and retention profiles of carbon nanoparticles (CNPs) and graphene oxide quantum dots (GOQDs) through column experiments in saturated porous media. CNPs and GOQDs (30 mg/L) were dispersed in natural river water (RW) and passed through the column at a flow rate of 1 mL/min, which mimicking the natural water flow rate. After every 10 min, the column effluents were collected and the mass recovery and retention profiles were monitored. Results indicated that the transport of both carbonaceous colloids was predominantly controlled by surface potential and ionic composition of natural water. The CNPs with its high surface potential (−40 mV) exhibited more column transport and was less susceptible to solution pH (5.6–6.8) variation as compared to GOQDs (−24 mV). The results showed that, monovalent salt (NaCl) was one of the dominating factors for the retention and transport of carbonaceous colloids compared to divalent salt (CaCl2). Furthermore, the presence of natural organic matter (NOM) increased the transport of both carbonaceous colloids and thereby decreases the tendency for column retention

    Geochemical characteristics of rare earth elements in different types of soil: A chemometric approach

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    Rare earth elements (REEs) are becoming significant due to their huge applications in many industries, large-scale mining and refining activities. Increasing usage of such metals pose negative environmental impacts. In this research ICP-MS has been used to analyze soil samples collected from former ex-mining areas in the depths of 0–20 cm, 21–40 cm, and 41–60 cm of residential, mining, natural, and industrial areas of Perak. Principal component analysis (PCA) revealed that soil samples taken from different mining, industrial, residential, and natural areas are separated into four clusters. It was observed that REEs were abundant in most of the samples from mining areas. Concentration of the rare elements decrease in general as we move from surface soil to deeper soils

    Reviews of the toxicity behavior of five potential engineered nanomaterials (ENMs) into the aquatic ecosystem

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    Presently, engineered nanomaterials (ENMs) are used in a wide variety of commercial applications, resulting in an uncontrolled introduction into the aquatic environment. The purpose of this review is to summarize the pathways and factors that controlling the transport and toxicity of five extensively used ENMs. These toxicological pathways are of great importance and need to be addressed for sustainable implications of ENMs without environmental liabilities. Here we discuss five potentially utilized ENMs with their possible toxicological risk factors to aquatic plants, vertebrates model and microbes. Moreover, the key effect of ENMs surface transformations by significant reaction with environmental objects such as dissolved natural organic matter (DOM) and the effect of ENMs surface coating and surface charge will also be debated. The transformations of ENMs are subsequently facing a major ecological transition that is expected to create a substantial toxicological effect towards the ecosystem. These transformations largely involve chemical and physical processes, which depend on the properties of both ENMs and the receiving medium. In this review article, the critical issues that controlling the transport and toxicity of ENMs are reviewed by exploiting the latest reports and future directions and targets are keenly discussed to minimize the pessimistic effects of ENMs. Keywords: Nanotechnology, Nanomaterials, Ecotoxicology, Environmental transport, Risk assessmen

    Arsenic, Zinc, and Aluminium Removal from Gold Mine Wastewater Effluents and Accumulation by Submerged Aquatic Plants (Cabomba piauhyensis, Egeria densa, and Hydrilla verticillata)

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    The potential of three submerged aquatic plant species (Cabomba piauhyensis, Egeria densa, and Hydrilla verticillata) to be used for As, Al, and Zn phytoremediation was tested. The plants were exposed for 14 days under hydroponic conditions to mine waste water effluents in order to assess the suitability of the aquatic plants to remediate elevated multi-metals concentrations in mine waste water. The results show that the E. densa and H. verticillata are able to accumulate high amount of arsenic (95.2%) and zinc (93.7%) and resulted in a decrease of arsenic and zinc in the ambient water. On the other hand, C. piauhyensis shows remarkable aluminium accumulation in plant biomass (83.8%) compared to the other tested plants. The ability of these plants to accumulate the studied metals and survive throughout the experiment demonstrates the potential of these plants to remediate metal enriched water especially for mine drainage effluent. Among the three tested aquatic plants, H. verticillata was found to be the most applicable (84.5%) and suitable plant species to phytoremediate elevated metals and metalloid in mine related waste water

    Distribution and contamination assessment of potentially harmful elements (As, Pb, Ni, Cd) in top soil of Penang Island, Malaysia

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    This study discusses the distribution and contamination levels of potentially harmful elements (As, Pb, Ni, and Cd) in the urban top soil of Penang Island, one of the most important urban areas in Malaysia. The total surface area of Penang Island is 297 km2. Thirty-one surface soil samples (0–20 cm) were collected, digested and analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for As, Pb, Ni, and Cd. The result showed that the mean concentrations of selected metals in soils were arranged in the following decreasing order: Pb > As > Ni > Cd. In terms of different soil types, soils derived from quaternary deposit have higher mean concentration of Pb, Ni, and Cd as compared to the granite residual soils which accumulate higher mean concentration of As. On the spatial distribution maps, As, Pb, Ni, and Cd are mainly concentrated in the north-to-north eastern areas of Penang Island and near to the main city, which are characterized by major residential and business areas. Thus, it suggests that the anthropogenic source is the main contributor to the As, Pb, Ni, and Cd in the top soil of Penang Island. Both Pearson correlation analysis and principal component analysis showed a strong positive correlation between Pb and Cd which indicated that they may be derived from a similar source. The contamination factor assessment indicates moderate contamination level for Pb and Ni and no element enrichment level for As and Cd. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature
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