Explicit construction of rectangular differentiation matrices

Spectral discretizations based on rectangular differentiation matrices have recently been demonstrated to be a convenient means of solving linear and nonlinear ordinary differential equations with general boundary conditions and other side constraints. Here, we present explicit formulae for such matrices

A characterisation of the properties of environmentally-friendly composite materials

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Tensile Properties of Luffa Acutangula Reinforced Polymer Composite

In recent years, there has been a growing trend in the popularity of natural fiber-reinforced polymer composites (NFRPC). Numerous researchers have put forward various alternatives to synthetic fibers. Luffa is one of the many natural fibers can be integrated into NFRPCs. Luffa with its unique interconnecting branch (mat/mesh) is suitable for NFRPCs. In this study, luffa reinforced high-density polyethylene (Luffa/HDPE) composite was fabricated using compression molding machine. In the preparation of the fiber, Luffa were cylindrically cut-out and opened into sheets form. The fiber was then laminated with high-density polyethylene (HDPE) film using compression molding method. The proposed fabricated composite consisting of a fiber volume fraction (FVF) of 7%, 14%, 21%, 27% and 30%. Tensile properties of the Luffa/HDPE composite were determined. SEM was used to study the interlamination and delamination of the composite. Tensile test shows that the increase of FVF enhanced the tensile strength of Luffa/HDPE composite. Tensile strength has gradually increased from 7 % to 21 % FVF. Though, tensile strength declines after 21% FVF

Tensile Properties of Luffa Acutangula Reinforced Polymer Composite

In recent years, there has been a growing trend in the popularity of natural fiber-reinforced polymer composites (NFRPC). Numerous researchers have put forward various alternatives to synthetic fibers. Luffa is one of the many natural fibers can be integrated into NFRPCs. Luffa with its unique interconnecting branch (mat/mesh) is suitable for NFRPCs. In this study, luffa reinforced high-density polyethylene (Luffa/HDPE) composite was fabricated using compression molding machine. In the preparation of the fiber, Luffa were cylindrically cut-out and opened into sheets form. The fiber was then laminated with high-density polyethylene (HDPE) film using compression molding method. The proposed fabricated composite consisting of a fiber volume fraction (FVF) of 7%, 14%, 21%, 27% and 30%. Tensile properties of the Luffa/HDPE composite were determined. SEM was used to study the interlamination and delamination of the composite. Tensile test shows that the increase of FVF enhanced the tensile strength of Luffa/HDPE composite. Tensile strength has gradually increased from 7 % to 21 % FVF. Though, tensile strength declines after 21% FVF

Tensile Properties of Pandanus Atrocarpus based Composites

Pandanus atrocarpus, or locally known as mengkuang plant is likely to be potential natural fibre reinforcement in composite. Both the Pandanus leaves, and fibres extracted from the Pandanus leaves were used in composite fabrication. Fibres were extracted from Pandanus leaves with water retting process. Pandanus composites were laminated using compression moulding method. The tensile properties of composite laminates based on lamination of Pandanus leaf- and extracted Pandanus fibre-reinforced polyethylene were investigated. Tensile tests have shown that composite laminates based on extracted Pandanus fibre reinforced polyethylene were more superior than using the Pandanus leaf itself without extracting its fibre. Tests exhibited that increasing the volume fraction of Pandanus fibre resulted in strength increase. This suggests that Pandanus fibre- based composites could offer a range of mechanical properties for use in the engineering industry

The use of Mindfulness Acceptance Commitment (MAC) approach for Malaysian elite triathletes

Mindfulness Acceptance Commitment (MAC) approach has been introduced into the sport psychology field and has shown a lot of interest in the applied practices. Athletes who receive MAC approach are taught to deal with challenging internal experiences in a non-judgmental way, choosing to persist with their task-at-hand despite discomforts and to remain focused on being grounded at the present moment. In Malaysia, the elite triathletes have not been exposed to the MAC approach before. This paper aims to describe how the MAC approach was provided to the Malaysian elite triathletes. MAC was taught over six weeks, with one MAC theme introduced per week. Each triathlete was given a one-on-one session of 60-90 minutes per week with homework and practical exercises. After six weeks, the triathletes reported marked improvement in their sport and additional improvements in other domains of their life. Considering the promising improvements of the elite triathletes who received the MAC approach, it is worth considering that the MAC approach should be adapted and incorporated into the triathlon sport

Characterisation of alkaline treatment and fiber content on the physical, thermal and mechanical properties of ground coffee waste/oxo-biodegradable HDPE Biocomposites

Effect of alkali treatment on ground coffee waste/oxo-biodegradable HDPE (GCW/oxoHDPE) composites was evaluated using 5%, 10%, 15% and 20% volume fraction of GCW. The composites were characterize using structurally (fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM)), thermally (thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC)), mechanically (tensile and impact test), and water absorption. FTIR spectrum indicated the eradication of lipids, hemicellulose, lignin and impurities after the treatments the lead to an improvement of the filler/matrix interface adhesion. This is confirmed by SEM results. Degree of crystallinity index was increased by 5% after the treatment. Thermal stability for both untreated and treated GCW composites were alike. Optimum tensile result achieved when using 10% volume fraction with enhancement of 25% for tensile strength and 24% for tensile modulus compared to untreated. Specific tensile strength and modulus had improved as the composite has lower density. The highest impact properties was achieved when using 15% volume fraction that lead to an improvement of 6%. Treated GCW composited show a better water resistance with 57% improvement compared to untreated. This light weight and ecofriendly biocomposite has the potential in packaging, internal automotive parts, lightweight furniture and other composite engineering applications

Adverse health effects associated with household air pollution: a systematic review, meta-analysis, and burden estimation study

Background: 3 billion people worldwide rely on polluting fuels and technologies for domestic cooking and heating. We estimate the global, regional, and national health burden associated with exposure to household air pollution. Methods: For the systematic review and meta-analysis, we systematically searched four databases for studies published from database inception to April 2, 2020, that evaluated the risk of adverse cardiorespiratory, paediatric, and maternal outcomes from exposure to household air pollution, compared with no exposure. We used a random-effects model to calculate disease-specific relative risk (RR) meta-estimates. Household air pollution exposure was defined as use of polluting fuels (coal, wood, charcoal, agricultural wastes, animal dung, or kerosene) for household cooking or heating. Temporal trends in mortality and disease burden associated with household air pollution, as measured by disability-adjusted life-years (DALYs), were estimated from 2000 to 2017 using exposure prevalence data from 183 of 193 UN member states. 95% CIs were estimated by propagating uncertainty from the RR meta-estimates, prevalence of household air pollution exposure, and disease-specific mortality and burden estimates using a simulation-based approach. This study is registered with PROSPERO, CRD42019125060. Findings: 476 studies (15·5 million participants) from 123 nations (99 [80%] of which were classified as low-income and middle-income) met the inclusion criteria. Household air pollution was positively associated with asthma (RR 1·23, 95% CI 1·11–1·36), acute respiratory infection in both adults (1·53, 1·22–1·93) and children (1·39, 1·29–1·49), chronic obstructive pulmonary disease (1·70, 1·47–1·97), lung cancer (1·69, 1·44–1·98), and tuberculosis (1·26, 1·08–1·48); cerebrovascular disease (1·09, 1·04–1·14) and ischaemic heart disease (1·10, 1·09–1·11); and low birthweight (1·36, 1·19–1·55) and stillbirth (1·22, 1·06–1·41); as well as with under-5 (1·25, 1·18–1·33), respiratory (1·19, 1·18–1·20), and cardiovascular (1·07, 1·04–1·11) mortality. Household air pollution was associated with 1·8 million (95% CI 1·1–2·7) deaths and 60·9 million (34·6–93·3) DALYs in 2017, with the burden overwhelmingly experienced in low-income and middle-income countries (LMICs; 60·8 million [34·6–92·9] DALYs) compared with high-income countries (0·09 million [0·01–0·40] DALYs). From 2000, mortality associated with household air pollution had reduced by 36% (95% CI 29–43) and disease burden by 30% (25–36), with the greatest reductions observed in higher-income nations. Interpretation: The burden of cardiorespiratory, paediatric, and maternal diseases associated with household air pollution has declined worldwide but remains high in the world’s poorest regions. Urgent integrated health and energy strategies are needed to reduce the adverse health impact of household air pollution, especially in LMICs. Funding: British Heart Foundation, Wellcome Trus