19672 research outputs found
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Saccharin: a cheap and mild acidic agent for the synthesis of azo dyes via telescoped dediazotization
No full textGreen synthesis methods are considered as a safer alternative to the conventional synthetic processes due to their eco-friendly nature, cost-effectiveness, and easy handling. In the present study, an eco-friendly and sustainable method for the synthesis of stable arenediazonium has been developed using saccharin as a cheap and mild acidic agent and tert-butyl nitrite as a diazotization reagent for the first time. These stable intermediates were used in the azo coupling reaction with 4-hydroxybenzaldehyde via telescoped dediazotization. The current method has advantages such as reduced waste by avoiding solvent for the purification of intermediate in diazotization step, cost-effectiveness, simple experimental procedure, good yield of azo dyes, metal-free waste, and environmentally benign conditions. An interesting aspect of this study is the recovery of saccharin from the reaction, which could be reused. © 2019 Walter de Gruyter GmbH, Berlin/Boston
Conceptual framework for risk communication between emergency response team and management team at healthcare facilities: A Malaysian perspective
No full textThe requirement to establish a Disaster Risk Management Plan (DRMP) and Emergency Response Team (ERT) in Malaysia is stated in the Occupational Safety and Health Act 1994. DRMP provides first responder such as ERT a standard operating procedure (SOP) when assisting evacuation and performing search and rescue. In performing such tasks, ERT requires sufficient information outline in the DRMP and other risk communication activities that are conducted by the management team. However, past fire incidents at public hospitals in Malaysia shows that the current practice of risk communication at public hospitals does not facilitate the ERT's decision-making process. This paper intends to propose a conceptual framework of risk communication that can guide the management team at public hospitals in delivering information regarding fire safety to the ERT to ensure its effectiveness. Standards on disaster risk management, public hospital's contingency plans, and past research were reviewed. This framework provides an overall idea of how the decision-making process is made among the ERT members. This shows the involvement of risk communication and risk perception that can affect the ERT's judgement and actions taken during the response phase. Findings of this paper include factors that address people's perception towards risk and elements of risk communication that should be considered to develop and improve risk communication policy. © 201
Forecasting Solar Power Using Hybrid Firefly and Particle Swarm Optimization (HFPSO) for Optimizing the Parameters in a Wavelet Transform-Adaptive Neuro Fuzzy Inference System (WT-ANFIS)
No full textSolar power generation deals with uncertainty and intermittency issues that lead to some difficulties in controlling the whole grid system due to imbalanced power production and power demand. The forecasting of solar power is an effort in securing the integration of renewable energy into the grid. This work proposes a forecasting model called WT-ANFIS-HFPSO which combines the wavelet transform (WT), adaptive neuro-fuzzy inference system (ANFIS) and hybrid firefly and particle swarm optimization algorithm (HFPSO). In the proposed work, the WT model is used to eliminate the noise in the meteorological data and solar power data whereby the ANFIS is functioning as the forecasting model of the hourly solar power data. The HFPSO is the hybridization of the firefly (FF) and particle swarm optimization (PSO) algorithm, which is employed in optimizing the premise parameters of the ANFIS to increase the accuracy of the model. The results obtained from WT-ANFIS-HFPSO are then compared with several other forecasting strategies. From the comparative analysis, the WT-ANFIS-HFPSO showed superior performance in terms of statistical error analysis, confirming its reliability as an excellent forecaster of hourly solar power data. © 2019 by the authors
The colour stability of natural blue dye extracted from Clitoria ternatea L. in poly(acrylamide-co-acrylic acid) coating film
No full textPurpose: This paper aims to focus on a comparison study of the visible stability of natural blue dye consisting anthocyanin molecules extracted from Clitoria ternatea in coating films. Design/methodology/approach: The coating films were prepared by mixing the blue dye with poly(acrylamide-co-acrylic acid) in three different weight ratios. Samples were coded as 10PBA, 15PBA and 20PBA, where PBA is the abbreviation for poly acrylamide-co-acrylic acid, blue dyes and anthocyanin. The number at the beginning of each code represents the weight percentage of poly(acrylamide-co-acrylic acid) to natural blue dye. The mixtures were applied on separate glass substrates to form coating films. Another set of samples were prepared for the comparison study with a commercial acrylic clear coat (cc) applied on the surface of the 10PBA, 15PBA and 20PBA coating films. These coating films were coded 10PBAcc, 15PBAcc and 20PBAcc. The purpose of the clear coat is to observe how it affects the colour stability of the blue coating films with respect to time. All samples were exposed to the ultraviolet (UV) source, an 18 W Philips TL-D 18w/830 UV fluorescent lamp. The UV lamp was placed 15 cm above the surface of the samples for 35 days. The colour of the coatings was measured using CIE L*a*b* colour space coordinate. Findings: The results obtained show 10PBA and 10PBAcc have the highest colour stability after 35 days of exposure to UV light. The reflectivity of the coating films was also measured during exposure to UV lamp. Reflectivity measurements also showed that 10PBA and 10PBAcc coating films had the highest reflective stabilities. Research limitations/implications: The potential of using natural blue dye consisting anthocyanin in coating film to obtain high colour stability. Practical implications: The coating film developed in this work is suitable to be applied on glass substrates. Originality/value: The application of anthocyanin dye extracted from the Clitoria ternatea L. as a colourant in coating films. © 2019, Emerald Publishing Limited
Features of the inter-hemispheric field-aligned current system over Malaysia ionosphere
No full textMagnetic records of the declination (D) component for the solar quiet year 2011–2013 obtained from Magnetic Data Acquisition System (MAGDAS) at Langkawi (Geog. Lon. 99.68∘ E, Geog. Lat. 6.30∘N), Malaysia were utilized in this study. The minutes averages were used to delineate the diurnal (Sq(D)) variation. The monthly mean (MSq(D)) and their seasonal variabilities (SVq(D)) were also analysed. The Sq(D) and their MSq(D) exhibit smooth regular occurring pattern in the month of April–September and became highly perturbed in October–March across the years. The highest positive (∼3.5 arc-min) and the negative (∼−3.0 arc-min) values were observed in August 2011 during the dawn and noon sectors. These maxima shifted to July and September in 2012 with peaks ∼3.2 and −3.0 arc-min. In 2013, the positive maximum (∼3.0 arc-min) and its negative (∼−2.5 arc-min) were again seen in August. This implies that the dawn and noon sectors of August 2011 and 2013 are strongly influenced by IHFACs and this effect shifted to July and September in 2012. IHFACs through the years flow from the winter to summer hemisphere during the noon and dusk sectors and flow in opposite direction during the dawn sector. The day-to-day magnitudes of Sq(D) and MSq(D) seems to suggest the inter-hemispheric imbalance of the ionospheric Sq current earlier established by Van Sabben as the cause of IHFACs is not strongly affected by the changes in annual solar variation. Dusk-side IHFACs were observed to be northbound in all the seasons with the exception of June solstice. The direction of IHFACs does not change except in April and November. The current intensity is not large in solstices except in August 2011 and 2013 but it shifted to July in 2012. The result further showed that the magnitude of the duskside IHFACS is determined to some extent by the strength of the noontime IHFACs. IHFACs were generally observed to be greater during the daytime than night-time hours. © 2018 Elsevier Lt
Phase III, randomised, double-blind, multicentre study to evaluate the efficacy and safety of vonoprazan compared with lansoprazole in Asian patients with erosive oesophagitis
No full textObjective To establish the non-inferior efficacy of vonoprazan versus lansoprazole in the treatment of Asian patients with erosive oesophagitis (EO). Design In this phase III, double-blind, multicentre study, patients with endoscopically confirmed EO were randomised 1:1 to receive vonoprazan 20 mg or lansoprazole 30 mg, once daily for up to 8 weeks. The primary endpoint was EO healing rate at 8 weeks. The secondary endpoints were EO healing rates at 2 and 4 weeks. Safety endpoints included treatment-emergent adverse events (TEAEs). Results In the vonoprazan (n=238) and lansoprazole (n=230) arms, 8-week EO healing rates were 92.4% and 91.3%, respectively (difference 1.1% (95% CI-3.822% to 6.087%)). The respective 2-week EO healing rates were 75.0% and 67.8% (difference 7.2% (95% CI-1.054% to 15.371%)), and the respective 4-week EO healing rates were 85.3% and 83.5% (difference 1.8% (95% CI-4.763% to 8.395%)). In patients with baseline Los Angeles classification grade C/D, 2-week, 4-week and 8-week EO healing rates were higher with vonoprazan versus lansoprazole (2 weeks: 62.2% vs 51.5%, difference 10.6% (95% CI-5.708% to 27.002%); 4 weeks: 73.3% vs 67.2%, difference 6.2% (95% CI-8.884 to 21.223); and 8 weeks: 84.0% vs 80.6%, difference 3.4% (95% CI-9.187% to 15.993%)). Overall, EO healing rates appeared higher with vonoprazan versus lansoprazole. TEAE rates were 38.1% and 36.6% in the vonoprazan and lansoprazole group, respectively. Conclusion Our findings demonstrate the non-inferior efficacy of vonoprazan versus lansoprazole in terms of EO healing rate at 8 weeks in this population. Safety outcomes were similar in the two treatment arms. © 2020 Author(s)
Seismic characteristics of X-cable braced frames bundled with a pre-compressed spring
No full textThe performance of steel structures can be enhanced against lateral loads by various methods; of these, bracing systems are the most common. Past studies have shown that tension-only braced frames provide more structural stability, and hence offer better resistance when the frame is subjected to lateral loads. In a comparison between a braced and bare frame, the additional efficiency offered by the bracing depends on the selection of bracing system. This paper proposes a cable brace system with a pre-compressed spring (PCS) that bundles the wire-rope bracing members at the intersection point. Both experimental and analytical studies are conducted, and no loosening in the cable is observed, as the cables are held tension by the spring's force; thus the ability of the bracing system to cause impulses is eliminated. The final strength of the cables is reached at larger lateral displacement of the frame compared to ordinary cross cable bracing system. The equations involved in the proposed technique are discussed before being verified using finite element (FE) solutions based on ABAQUS analysis. It can be concluded that the ductility and strength of the tested specimens was significantly improved by means of the proposed technique
Robust remote heart rate estimation from multiple asynchronous noisy channels using autoregressive model with Kalman filter
No full textRemote heart rate measurement has many powerful applications, such as measuring stress in the workplace, and the analysis of the impact of cognitive tasks on breathing and heart rate variability (HRV). Although many methods are available to measure heart rate remotely from face videos, most of them only work well on stationary subjects under well-controlled conditions, and their performance significantly degrades under subject's motions and illumination variation. We propose a novel algorithm to estimate heart rate. Also, it can differentiate between a photo of a human face and an actual human face meaning that it can detect false signals and skip them. The method obtains ROIs using facial landmarks, then it rectifies illumination based on Normalized Least Mean Square (NLMS) adaptive filter and eliminates non-rigid motions based on standard deviation of fixed length of the signal's segments. The method employs the RADICAL technique to extract independent subcomponents. The heart rate measures for each subcomponent, are estimated by analysis of frequency signal to find the one with the highest magnitude. A two-steps data fusion method is also introduced to combine current and previous measured heart rates to calculate a more accurate result. In this paper, we explore the potential of our algorithm on two self-collected, and DEAP databases. The results of three experiments demonstrate that our algorithm substantially outperforms all previous methods. Moreover, we investigate the behavior of our algorithm under challenging conditions including the subject's motions and illumination variation, which shows that our algorithm can reduce the influences of illumination interference and rigid motions significantly. Also, it indicates that our algorithm can be used for the online environment. Finally, the application of our algorithm in search and rescue scenarios using drones is considered and an experiment is conducted to investigate the algorithm's potential to be embedded in drones
Dual-mode output in half open cavity random fibre laser
No full textThe mechanism of laser mode in fibre laser has been a popular talking issue since decades ago. Numerous mode mechanisms are revealed from time to time such as LP and TM. From these modes, fundamental mode and higher-order mode exhibit practical applications such as in fibre laser. Based on this perspective, we employ the mode mechanism in random fibre laser with half open cavity that generates dual-mode output which consists of LP01 and LP11 modes. The investigation on our proposed laser setup is beneficial for developing photonics system that involves the implementation of few-modes mechanism
Probing the interaction of 2,4-dichlorophenoxyacetic acid with human serum albumin as studied by experimental and computational approaches
No full textTo characterize the binding of a widely used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D) to the major transporter in human circulation, human serum albumin (HSA), multi-spectroscopic approaches such as fluorescence, absorption and circular dichroism along with computational methods were employed. Analysis of the fluorescence and absorption spectroscopic data confirmed the 2,4-D–HSA complex formation. A static quenching mechanism was evident from the inverse temperature dependence of the KSV values. The complex was stabilized by a weak binding affinity (Ka = 5.08 × 103 M−1 at 298 K). Quantitative analysis of thermodynamic data revealed participation of hydrophobic and van der Waals interactions as well as hydrogen bonds in the binding process. Circular dichroism and three-dimensional fluorescence spectral results showed structural (secondary and tertiary) changes in HSA as well as microenvironmental perturbation around protein fluorophores (Trp and Tyr residues) upon 2,4-D binding. Addition of 2,4-D to HSA was found to improve protein's thermal stability. Competitive displacement results as well as computational analyses suggested preferred location of the 2,4-D binding site as Sudlow's site I (subdomain IIA) in HSA