19672 research outputs found
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Development of a non-domestic building refurbishment scheme for Malaysia: A Delphi approach
No full textBuilding refurbishment is a key in promoting environmentally sustainable development due to its potential for reducing greenhouse gas emissions and energy consumption associated with existing buildings. The general metrics for assessing the impacts of refurbishment have not been established for existing buildings in most of the countries. In Malaysia, there is currently no single environmental assessment scheme for building refurbishment. The existing environmental assessment schemes are not sufficiently robust, as they do not include factors such as quality of services and economics. It is essential to have a customised suite of sustainability schemes specifically designed for the Malaysian context to facilitate best practice for non-domestic refurbishment assessment. A comprehensive Delphi process was developed to assist in the identification of suitable assessment schemes for use in non-domestic buildings. Three successive rounds of surveys were conducted with ten Delphi experts with expertise in sustainability and green assessment. The study revealed that energy related factors such as air-conditioning were ranked as the most important assessment theme for refurbishment, followed by indoor environmental quality and water assessment. The findings of this research will be used to develop a weighting system by using the analytic hierarchy process in the next research stage, leading to a complete refurbishment environmental assessment scheme
Arc related dioritic–granodioritic magmatism from southeastern Peninsular Malaysia and its tectonic implication
No full textIn Peninsular Malaysia, Late Cretaceous (95-76 Ma) plutons are found within the Eastern Belt. Their compositions are diverse, ranging from biotite granite, hornblende granodiorite, diorite, and gabbro. The Aur Pluton is the easternmost body and is exposed in the Johore Archipelago, southeast of Peninsular Malaysia. The rock types vary from diorite, quartz monzodiorite and granodiorite. Ar-Ar stepheating age of the diorite and zircon U/Pb age of the granodiorite yielded ages of 77.9 ± 2 Ma and 79 ± 0.7 Ma, respectively. The overall major and trace element trends are consistent with two magmatic pulses, i.e., diorite-quartz monzodiorite and granodiorite. The diorite-quartz monzodiorites are characterized by high Fe2O3 (6.7–8.3 wt.%), CaO (5.5–7.6 wt.%), MgO (2.9–4.1 wt.%) and high but variable Sr concentrations (570–1300 ppm). The granodiorites have significantly higher total alkali content (8.49–8.91%), with high K2O concentrations (3.8–4.6%) and low Fe2O3 (4.7–6.5%), CaO (2.7–3.9%) and MgO (1.4–2.0%) concentrations. Low Nb/U and distinct Pb anomalies suggest that both rock types are likely derived from the crust. Furthermore, elevated LREE and trace element contents for the granodiorites, e.g., FTh (10–20 ppm), Pb (10–30 ppm), and U (2–5 ppm), also indicate that upper crustal components are involved in the magma generation. The dioritic rocks are chemically classified as calc-alkaline volcanic arc (VAG) rocks, but they also have field relationships and mineralogies typically associated with an active continental margin (ACM)
Simultaneous microbeam IBA and beam-induced luminescence analysis of strained doped silica fibre radiation dosimeters
No full textWe demonstrate that the simultaneous combination of ion beam analysis (IBA) and ion beam induced luminescence (IL) can reveal valuable information concerning the performance of strained doped silica fibre thermoluminescence microdosimeters. The micron scale spatial resolution and low detection limits of IBA allow the lateral distribution of dopant elements to be mapped and then correlated with the distribution of prompt radioluminescence. Measurement of the decay of the IL signal with dose provide information concerning the saturation of the subsequent TL signal at high doses. MeV ion beams can deposit relatively high energy in localized, well-quantified small volumes and so this method is valuable for studying high dose effects in TL dosimeters. We describe a simple modification of the target chamber microscope which enables sensitive low background light detection in two wavelength bands and present preliminary results from three types of germanium doped silica fibre dosimeter
Loop dynamics behind the affinity of DARPins towards ERK2: Molecular dynamics simulations (MDs) and elastic network model (ENM)
No full textThe binding affinity and dynamics profiles of non-phosphorylated extracellular regulated kinase 2 (ERK2), in complex with DARPins (designed ankyrin repeat proteins) as a phosphorylation inhibitor, has been investigated using molecular dynamics simulations (MDs) and elastic network model (ENM). The study investigates the effect of ERK2 loop dynamics on its specificity, upon binding with DARPins. From experiments, DARPin E40 has been found as a specific binder (E40/ERK2) with higher binding affinity while DARPin pE59 has lower binding affinity towards ERK2 (pE59/ERK2). Theoretical binding affinities along the 100 ns molecular dynamics simulations between DARPins and ERK2 were analyzed and found in good agreement with the experiments, where BFE (binding free energy) of E40/ERK was found to be much lower (more favorable) as compared to that of pE59/ERK2 with the contribution of activation loop and αG loops. Moreover, elastic network model (ENM) studies successfully delineate the dynamics of four loops of ERK2 (activation, αG, MAPK and L16) along the trajectories. Slow eigenvectors from global mode shapes and dynamic cross correlation indicate the responsible regions for the binding. The specificity of DARPins can be discriminated by the binding free energy of the activation and αG loop, which indicated the stronger interaction of these region in E40/ERK2. Robustness of the average properties (mean-square fluctuations, eigenvectors from global mode shapes, dynamic cross-correlations) controlled by the low frequency motions, which are reproduced in both MDs and ENM suggested that GNM based on a coarsegrained single-site-per-residue model can be used as a complimentary and fast analytical approach to investigate the structural dynamics
Electronic, bonding and optical properties of the LiGaGe2X6 (X = S, Se, and Te) compounds: An ab initio study
No full textIn order to gain an insight into the bonding and to characterize linear and nonlinear optical properties of three infrared LiGaGe2S6, LiGaGe2Se6, and LiGaGe2Te6 compounds, we performed an ab initio calculation based on density functional theory. The calculations determined lattice parameters, band gaps, dipole moments, and second harmonic components that commonly agreed well with the available experimental data. We show in this article, through a large body of calculations, the trend in the row of participating anions, S ⟶ Se ⟶ Te, enhances the polarization effect and the coordination structure distortions in the polyhedra groups forming the bonding pattern of the cell. This one also affects both the electronic and the optical properties, making the compounds more propitious for device-based optical applications
Catalytic hydrodeoxygenation of dibenzofuran to fuel graded molecule over mesoporous supported bimetallic catalysts
No full textThe present study focuses on hydrocarbons production (bicyclohexane) from hydrodeoxygenation of dibenzofuran over Cu-Ni/Ti-MCM-41 catalysts at mild reaction conditions. The hydrodeoxygenation activity of Cu-Ni/Ti-MCM-41 catalysts was optimized via Ni loading at reaction conditions of 260 °C, 10 MPa and 6 h in batch reactor. Those loading arounds the optimum points (5–10 wt%) were characterized by TPO, RAMAN, XRD, TPR, FESEM and ICP-MS analysis. The catalytic reactions pathway for conversion of dibenzofuran to bicyclohexane were investigated using optimum catalysts (7.5 wt% Ni loading) and reaction mechanism was then proposed. The characterization results showed that Cu-Ni dispersion and catalysts reducibility decreased with continuous increment of Ni loading above 7.5 wt%. The structure activity correlation showed that the dispersion and reducibility enhanced conversions and hydrocarbons selectivity. The highest conversion of dibenzofuran (85.46%) and selectivity of bicyclohexane (58.77%) were found with 7.5% Ni loading. Further addition of Ni loading could lead to decreasing of both activity and selectivity due to poor dispersion and agglomeration as well as low reducibility as Ni loading crossed the optimum points. The product distribution study indicated that the presence of other by-product such as cyclohexyl-benzene, tetra-hydro-dibenzofuran, cyclohexyl-cyclohexanol, cyclohexyl-cyclohexanone, 1-cyclohexyl-cyclohexene, 2-cyclohexyl-phenol. The proposed reaction mechanisms showed that the conversion of dibenzofuran was initiated by partial hydrogenations followed by deoxygenations and subsequently dehydrated to bicyclohexane
Dissipative soliton resonance in a passively mode-locked praseodymium fiber laser
No full textDissipative soliton resonance (DSR) operation in a passively mode-locked praseodymium-doped fluoride fiber laser with a nonlinear optical loop mirror is proposed and demonstrated. A praseodymium-doped fluoride fiber is employed as the gain medium to allow lasing in the 1.3 μm region, and a stable square pulse emission at 1303 nm is observed. The width of the square pulse broadens with the increment of pump power, from 83 ns to 239 ns, whereas the peak power remains at a comparable level. The highest single pulse energy is recorded at around 2.3 nJ without the appearance of pulse breaking, validating the predicted DSR operation. To the best of author's knowledge, this work is the first study of DSR operation in the 1.3 μm region
Does Gold Act as a Hedge or a Safe Haven against Equity and Currency in Asia?
No full textIn recent years, uncertainty in financial markets has stimulated the need to explore alternative avenues for safeguarding wealth and managing risk. In this strand of research, gold has been particularly important due to its potential to mitigate risk and preserve wealth. This study investigates gold behaviour against equities and currencies in three regions across Asia. We follow Engle’s (2002) dynamic conditional correlation-multivariate generalized autoregressive conditional heteroscedasticity (DCC-MGARCH) model to test the gold link with equity and currency markets. We use a weekly series of exchange rate (national currency/the US dollar), equity and gold prices in national currency over the weekly period, 1995–2013. The sample consists of 12 countries covering East Asia, South Asia and Southeast Asia. Findings suggest that gold is just a diversifier against stocks in the Asian economies except in Korea, Singapore and Thailand. However, gold acts as a hedge and safe haven against Asian currencies—except China and Hong Kong—thus still preserving its monetary role
Concrete cover separation of reinforced concrete beams strengthened with near-surface mounted method: Mechanics based design approach
No full textThe primary mode of premature failure for near-surface mounted strengthened beams is the concrete cover separation. Due to its complexity, most of the prediction methods for concrete cover separation tend to be empirical based, which can limit their usage to specific near-surface mounted strengthening configurations. In response to that, this article presents a mechanics-based design which uses the moment-rotation approach and the global energy balance approach which is less reliant on empirical formulations, as the mechanics of reinforced concrete beam such as tension stiffening and propagation of concrete cover separation debonding crack are directly simulated rather than empirically derived. The proposed design procedure was validated against published experimental results of reinforced concrete beams strengthened with near-surface mounted carbon fibre–reinforced polymer bars, near-surface mounted carbon fibre–reinforced polymer strips or side-near-surface mounted carbon fibre–reinforced polymer bars and show good accuracy. As it is less reliant on empirical formulations, the proposed design procedure should be applicable to various near-surface mounted reinforcement configurations and materials. © The Author(s) 2019
Facile synthesis and characterization of novel dicarboxylate-Cu based MOFs materials
No full textThis work describes the synthesis and characterization of benzylimidazole (Bim) and piperazine (P) based metal organic framework (MOF) materials with two different linkers of adipic acid (A) and terephthalic acid (T) namely: ABim-Cu-MOF, TBim-Cu-MOF, AP-Cu-MOF, and TP-Cu-MOF. The physical and chemical characterization of these MOF materials were studied by elemental analysis (CHN), Fourier-transform infrared spectrometry (FT-IR), powder x-ray diffraction (PXRD), BET surface area and thermogravimetric analyses. The synthesized MOF materials were used as a modifier for carbon paste electrode to study its electrochemical behaviour towards ferricyanide. The electrochemical characterization revealed that the newly synthesized MOFs offer an excellent potential as electrode modifier for the redox reaction of ferricyanide. The reaction was reversible and diffusion controlled with the calculated diffusion coefficient values in the range of (4.86 × 10−5–2.66 × 10−5 cm2 s−1). © 2019 Elsevier B.V