19672 research outputs found
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Liquid–Liquid Equilibria for Binary Azeotrope Mixtures of Benzene and Alcohols Using Choline Chloride-Based Deep Eutectic Solvents
No full textIn this study, the COSMO-RS approach was used to qualitatively and quantitatively screen five choline chloride-based deep eutectic solvents (DESs) to separate the azeotropic binary formed between benzene and either methanol or ethanol. The activity coefficient at infinite dilution was calculated to evaluate the capacity, selectivity, and performance index of each DES. The interactions between the different species were also analyzed by interpreting the σ-profile and σ-potential of each component. Then, three DESs were selected for experimental validation. They were prepared by combining choline chloride with ethylene glycol, levulinic acid, and 1,2-propanediol. The best performance in terms of distribution ratio and selectivity was achieved with choline chloride/ethylene glycol DES with 1:4 molar ratio. The experimental tie-lines were successfully correlated using the NRTL model. Regardless of the system investigated, no DES was found in the raffinate phase, implying minimal cross-contamination. Finally, 2D NMR analysis was conducted to study the extraction mechanism of alcohol and its effect on the DES structure. This analysis revealed that, when the alcohol concentration exceeds 40 mol %, the DES' hydrogen bonds are broken such that only one phase occurs and thus the separation becomes impractical
Breeding habitats of mosquito larvae in a paddy growing area in Kuala Pilah, Negeri Sembilan, Malaysia
No full textSurveillance of mosquito larvae was performed in a paddy growing area in Kuala Pilah, Negeri Sembilan, Malaysia to uncover different types of breeding receptacles for mosquito larvae and species composition that bred in those positive receptacles. Fifty (50) natural and artificial receptacles were positive with mosquito breeding. About 96.00% of these positive receptacles were found outdoor. All positive indoor and most positive outdoor receptacles were conquered by Aedes albopictus Skuse while the rest were occupied by Culex quinquefasciatus Say. Population dynamics of Ae. albopictus in the study site should be constantly monitored and controlled to avoid the dispersal of mosquito-borne diseases such as dengue and chikungunya among local residents
Performance analysis of a cross-axis wind turbine from wind tunnel experiments
No full textWind energy has been considered as one of the primary renewable energy sources globally. In urban areas, due to the irregular arrangement of buildings, small scale wind turbine plays an important roles for household energy grid. In this study, a newly designed small scale wind turbine namely cross-axis wind turbine (CAWT), which combines the characteristics of horizontal and vertical axis wind turbines (HAWT and VAWT), was examined experimentally on the power performance in a low speed, open-loop circuit wind tunnel at Reynolds numbers of Re = 42900, 57100 and 71400. The results were compared to a traditional straight-bladed VAWT. The performance analyses are evaluated in terms of static performance, dynamic performance, and blade force measurement. The results of static and dynamic performances indicate that CAWT has not only better self-starting characteristics but also higher power coefficients over VAWT. The tangential forces measurement on the horizontal blade of CAWT proves its superior power performance compared to VAWT
Defect detection based on extreme edge of defective region histogram
No full textAutomatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection
Compact wireless IPT system using a modified voltage-fed multi-resonant class EF2 inverter
No full textWireless inductive power transfer (IPT) technology is used in many applications today. A compact and high-frequency primary side inverter is one of the most important parts of a WPT system. In this study, a modified class EF-type voltage-fed multi-resonant inverter has been proposed for WPT application at a frequency range of 85-100 kHz. Instead of an infinite input choke inductor, a resonant inductor is used to reduce loss and power density. The peak voltage stress across the MOSFET has been reduced to almost 60% from a class-E inverter using a passive clamping circuit. A simple yet effective design procedure has been presented to calculate the various component values of the proposed inverter. The overall system is simulated using MATLAB/SimPowerSystem to verify the theoretical concepts. A 500-W prototype was built and tested to validate the simulated results. The inverter exhibited 90% efficiency at nearly perfect alignment condition, and efficiency reduced gradually with the misalignment of WPT coils. The proposed inverter maintains zero-voltage switching (ZVS) during considerable load changes and possesses all the inherent advantages of class E-type inverters
Deconstructing the palm oil industry narrative in indonesia: Evidence from Riau province
No full textIndonesia is the leading global producer of crude palm oil. Mass production of palm oil requires large-scale land conversion, resulting in Indonesia having the world’s highest rate of annual primary forest loss. Given the contentious nature and scale of palm oil production, this article considers Indonesia as a variant of the developmental patrimonialism model often applied to African countries. Developmental patrimonialism in the Indonesian context suggests that state power — expressed through various discourse and policy coalitions — favours palm oil companies and seeks legitimation through claims about national economic benefits. This development model may lead to absolute poverty reduction, employment and tax revenue, but can also produce inequality, resource dependencies and environmental degradation. From the authors’ observations in Riau province, there is a mismatch between the national narrative of palm oil as a force for good and the conspicuous underinvestment in public services and infrastructure, which undermines the legitimacy of some palm oil industry claims. The complexity of village Riau casts further doubt on generalized claims about rural development. Local variance in Riau’s palm oil belt is attributed to, among other things, the complex nature of political patronage, uneven access to land, volatile pricing trends, problematic financing and loan schemes, and the role played by village cooperatives
Exploring the current and future role of the pharmacists in osteoporosis screening and management in Malaysia
No full textBackground Several studies have found that pharmacists can assist in screening and prevention of osteoporosis by referring patients for bone mineral density scans and counselling on lifestyle changes. In Malaysia, screening osteoporosis in all elderly women is not mandatory due to its cost. One approach to address this gap is to develop a pharmacist-led osteoporosis screening and prevention program. However, there is a paucity of data on the perspectives of Malaysian pharmacists in this area. Objective To explore the perspective of stakeholders (policy makers, doctors, pharmacists, nurses and patients) towards the role of pharmacists in osteoporosis screening and management. Setting A primary care clinic located within a teaching hospital in Kuala Lumpur, Malaysia. Method Patients (n = 20), nurses (n = 10), pharmacists (n = 11), doctors (n = 10) and policy makers (n = 5) were individually interviewed using a semi-structured topic guide. Purposive sampling was used. Interviews were transcribed verbatim and analysed using thematic analysis. Main outcome measure Perspective of stakeholders on the current and future role of pharmacists. Results All participants perceived pharmacists to be suppliers of medication, although there was some recognition of roles in providing medication advice. Nonetheless, these stakeholders were eager for pharmacists to expand their non-dispensing roles towards counselling, creating awareness and screening of osteoporosis. Interviewed pharmacists referred to their current role as ‘robotic dispensers’ and unanimously agreed to spread out to osteoporosis management role. Conclusion Under stakeholders there is a willingness to expand the role of pharmacists in Malaysia to non-dispensing roles, particularly in osteoporosis screening and management
Selection of Ankyrin Targeting HIV-1 Matrix and Identification of Its Binding Domain
No full textAnkyrin repeat protein is a novel class of non-antibody binding protein that can be applied as an alternative antiretroviral agent. Engineered ankyrin targeting the HIV-1 matrix (MA) would be a promising agent to interfere with HIV replication, since MA plays a major role in multiple processes of the viral life cycle. In this study, MA-specific ankyrin (AnkGAGG31) was isolated from an artificial ankyrin library using a semi-automated selection process with biotinylated MA-streptavidin magnetic beads. The AnkGAGG31-recognition site on MA was determined using both indirect and competitive ELISAs with overlapping MA tri-helical fragments and pentadecapeptides. The AnkGAGG31 showed the highest binding signal to the MA-fragments covering helices 2-3-4 and peptides corresponding to helix 2 (residues 25-43), which were found as the target epitope. This finding was further analyzed by molecular modeling and docking. The rational models of AnkGAGG31-MA complex indicated that the strong binding interaction was shown on helix 2 at key residues K27MA, K30M, and K32MA. Taken together, the identification of the binding domain on the MA target improves our understanding of the AnkGAGG31-MA interaction and provides the information necessary to design innovative protein targeting of the MA protein
Institutional Investors’ Monitoring and Stock Price Crash Risk: Evidence from Politically Connected Firms
No full textMotivated by recent studies on political connections and stock price crash risk, this study investigates whether there is an association between politically connected (POLCON) firms and stock price crash risk. Further, we examine whether institutional investors' ownership can moderate this association. Using a dataset of Malaysian firms for the period 2002-2012, we show that POLCON firms are associated with higher risk of stock price crashes. However, the positive association between POLCON and stock crashes is attenuated by higher institutional ownership, implying effective monitoring. Finally, we find that only local institutional investors can significantly mitigate the positive association between POLCON firms and stock price crash risk. This suggests that different types of institutional investors can produce different monitoring outcomes in POLCON firms