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Recycled soda lime silica glass‐filled polytetrafluoroethylene composites were prepared for substrate application at microwave frequencies. Various volume fractions (0.05–0.25) of the filler were dispersed in the polytetrafluoroethylene matrix. The composites' dielectric, mechanical, and thermal properties were examined with respect to the filler content. X‐ray diffraction data established the phase structure of the polytetrafluoroethylene matrix and recycled soda lime silica glass. Scanning electron microscope micrographs revealed uniform filler distribution at lower recycled soda lime silica contents, while energy dispersive x‐ray analysis showed the purity of the composites. The tensile strength of the composites reduced from 13.5 MPa to 4.26 MPa, while the moisture absorption and density raised from 0.07 % and 2.195 g/cm3 to 0.19 % and 2.228 g/cm3 when the recycled soda lime silica filler volume fraction was adjusted from 0.05–0.25. The lowest coefficient of thermal expansion values was recorded at 0.25 % recycled soda lime silica volume fraction, which increased from 31.12 ppm/°C to 68.32 ppm/°C at 40 °C to 200 °C. At 0.05 filler volume fraction, the respective values of ϵ' ${\varepsilon{} { {^\prime}}}$ , tanδ ${tan\delta }$ and Td ${{T}_{d}}$ of the composites decreased from 2.20, 0.0017, and 29.69 ps to 2.15, 0.0015, and 29.35 ps in the 8.2 GHz–12.4 GHz range. [ABSTRACT FROM AUTHOR]

Many initial value problems are difficult to be solved using ordinary, explicit step-by-step methods because most of these problems are considered stiff. Certain implicit methods, however, are capable of solving stiff ordinary differential equations (ODEs) usually found in most applied problems. This study aims to develop a new numerical method, namely the high order variable step variable order block backward differentiation formula (VSVO-HOBBDF) for the main purpose of approximating the solutions of third order ODEs. The computational work of the VSVO-HOBBDF method was carried out using the strategy of varying the step size and order in a single code. The order of the proposed method was then discussed in detail. The advancement of this strategy is intended to enhance the efficiency of the proposed method to approximate solutions effectively. In order to confirm the efficiency of the VSVO-HOBBDF method over the two ODE solvers in MATLAB, particularly ode15s and ode23s, a numerical experiment was conducted on a set of stiff problems. The numerical results prove that for this particular set of problem, the use of the proposed method is more efficient than the comparable methods. VSVO-HOBBDF method is thus recommended as a reliable alternative solver for the third order ODEs. [ABSTRACT FROM AUTHOR]

A dual-diamond-ring photonic crystal fiber (PCF)-based sensor is proposed and analyzed herein for the detection of the concentration of alcohol in aqueous solution. Commercially available finite element method (FEM)-based simulation software (COMSOL Multiphysics® version 4.3b) is utilized to conduct a rigorous numerical investigation. The sample is injected inside the fiber. Several crucial optical parameters such as the index difference, coupling length, transmission spectrum, peak wavelength shift, and sensitivity are studied while ensuring an anisotropic perfectly matched layer (A-PML) for X and Y polarization, respectively. The results indicate that the coupling length strongly depends on the concentration of the solution. Moreover, maximum sensitivities for the X and Y polarization of 6166 nm/RIU and 6000 nm/RIU, respectively, are found from the computational model. Based on this outstanding performance, it can be anticipated that practical implementation of such sensors would open a new horizon in the area of biomedical or clinical sensing. [ABSTRACT FROM AUTHOR]

CMC-NH4CH3CO2 complexes were characterized via theoretical and experimental approaches using molecular dynamics (MD) calculation, Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), and electrical impedance spectroscopy (EIS) analysis. These analyses successfully disclosed the structural and ion conduction properties of the bio-polymer electrolytes (BPE) system. The FTIR analysis further revealed that an interaction exists between the carboxylate anion group (COO-) from CMC and the H+ substructure of NH4CH3CO2. The ionic conductivity value at ambient temperature was found to achieve an optimum value of 5.07×10-6 S/cm for a system containing 10 wt% NH4CH3CO2. The ionic conductivity improvement was demonstrated via the increment on the amorphous phase of the BPEs system as shown in the XRD analysis upon the inclusion of NH4CH3CO2. Based on the IR-deconvolution approach, the mobility (µ) and diffusion coefficient (D) were found to influence the ionic conductivity and aligned with the theoretical molecular dynamic (MD) calculation. To evaluate the potential application of the CMC-NH4CH3CO2, an electrical double-layer capacitor (EDLC) was fabricated from the BPE and tested using cyclic voltammetry (CV), and charge-discharge (GCD) for 300 cycles and the BPE exhibited a specific of capacitance ~2.4 F/g. [ABSTRACT FROM AUTHOR]

Effect of heat generation and absorption on mixed convection flows in a sinusoidal heated lid-driven square cavity filled with a porous medium is investigated numerically. Both the vertical walls of the enclosure are insulated while the bottom wall is uniformly heated or cooled. The top wall is moving at a constant speed and is heated sinusoidally. The governing equations and boundary conditions are non-dimensionalized and solved numerically by using finite volume method approach along with SIMPLE algorithm together with non-uniform grid system. The effect of Darcy and heat generation parameters are investigated in terms of the flow, heat transfer, and Nusselt number. The results for stream function and isotherm are plotted and it is found that there have significant influence with the presence of heat generation and porous medium. [ABSTRACT FROM AUTHOR]

This was a cross-sectional study to identify the association between socio-cognitive factors (permissive attitude, social-norms, and self-efficacy) and intention towards sexual activity among 466 Malaysian school-going late adolescents (aged 18–19 years) in Kuantan, Malaysia. Majority were females (64.4%), Malays (67.4%) and Muslims (68.2%). Simple logistic regression from data collected by self-administered validated Youth Sexual-Intention Questionnaire (YSI-Q) showed significantly increase risk of having sexual intention for each unit increase in permissive attitude, social-norms and self-efficacy scores with the odds ratio (OR) of 1.424, 1.303 and 1.215, respectively. On the other hand, multivariate logistic regression resulted in male, non-Malay, ever-smoker students and permissive attitude showing significantly higher risk towards having sexual intention with the OR of 0.163 (male was the reference group), 5.110, 3.288 and 1.236, respectively. In order to reduce risky sexual behaviour among adolescents, school-based health education is essential. [ABSTRACT FROM AUTHOR]