Dynamic mechanical properties of Polyurethane Shape Memory Polymer Composites (SMPC) with different volume fractions of chopped strand mat glass fiber

Polyurethane shape memory polymer (SMP) are comparatively low in modulus. Hence, there is a need for incorporation of chopped strand mat glass fibers as reinforcing materials for the development of SMP composites (SMPC). In this study, glass fibers in different volume fractions which are 0%, 5%, 10%, 15% and 30% were used. The aim is to obtain the optimum volume fractions of glass fibers in SMPC based on the dynamic mechanical properties. The dynamic mechanical analysis (DMA) was carried out to determine the dynamic mechanical properties of the composite material. The dynamic parameters which reliance to temperature such as storage modulus (E’), loss modulus (Eâ€), damping factor (tan δ), glass transition temperature (Tg) values and others will gives the data regarding the adhesion of fiber-matrix of the composite material. The result shows that upon the addition of reinforcing fibers, an improvement in storage modulus was obtained. The tan δ peak value were decrease when the fiber volume fractions were increased, which confirming the reinforcing effectiveness of glass fibers in SMPC. It was also observed that the (Tg) increase upon the addition of reinforcing glass fibers. Summarizing, 15SMPC was chosen as the optimum volume fractions of glass fibers in SMPC. The parameter of the damping vibration demonstrates main significance for civil applications for building reliability and performance enhancement. Besides, it can foresee the impacts of temperature and time towards the polymer viscoelastic performance under various conditions. This study will provide several information to determine its functional application in future research

Performance of force circulation cross-matrix absorber solar heater integrated with latent heat energy storage material

The utilization of thermal energy storage in the thermal absorber applications has been increasingly important especially in the application where there is a mismatch between energy demand and energy supply. This technology implies that the heat is stored during charging or discharging process through melting and freezing of the thermal energy storage material so that it can be used in the future. This paper presents the outcome of the experimental investigation on the performance of cross-matrix absorber (CMA) utilizing paraffin as the thermal energy storage material. Experiments were carried out by exposing the CMA under different artificial solar radiation (300 W/m2, 500 W/m2, 700 W/m2 and 900 W/m2) for 30 minutes followed by 30 minutes of discharging process. Based on the observation, it was found that smaller mass flow rate value of 0.005 kg/s gave the highest temperature output regardless of the intensity of solar radiation as compared to the other after 30 minutes of charging process. In terms of heat gain by the thermal absorber, it was concluded that the highest mass flow rate of 0.01 kg/s passing through the absorber lead to the higher heat gain by the CMA, hence prolonged the cooling down / discharging period as shows by the result, where case with maximum mass flow rate (0.01 kg/s) consistently contributed to the higher heat gain by the absorber. This feature is very useful in the solar thermal collector related applications such as crop drying and domestic building heating. The heat gain by the absorber is also contributed by the intensity of the solar radiation

Influence of sulfate and chloride on the mechanical properties of fired clay masonry wall

This paper presents the influence of aggressive environment on the mechanical properties of masonry systems. The investigation involved the measurement of strength and modulus of elasticity of single leaf brick masonry wall which were built from fired clay bricks in conjunction with designation (iii) mortar with proportions of 1: 1: 6 (OPC: lime: sand). After being constructed, the specimens were cured under polythene sheet for 14 days in a controlled environment room with 80 ± 5% relative humidity and temperature of 25 ± 2ºC. The specimens were then exposed to the solution containing sodium sulfate and sodium chloride. The strength and modulus of elasticity of the brickworks were determined at the ages of 28, 56 and 180 days. The strength and modulus of elasticity of the brickworks, unbonded bricks, and mortar prisms were determined at the ages of 28, 56 and 180 days to quantify the contribution of bricks and mortar on the deformation of the masonry walls. As a result, fired clay brickwork is not durable and deteriorate in the environment containing sodium sulfate but durable in sodium chloride. The deterioration of the brickwork clearly influenced by the deterioration of mortar joint. The present of sodium chloride also retarding the attack of sodium sulphate

Parametric study of CNG-DI engine operational parameters by using analytical vehicle model

A parametric study of engine’s influential parameters on compressed natural gas direct injection (CNG-DI) engine’s torque was performed by using a dynamic, analytical model of the CNG-DI vehicle. The objective of the study is to analyze the effect of the selected six parameters on the engine’s total brake torque. The simulations were carried out to mimic the speed-sweep test procedure of the vehicle on a chassis dynamometer. Based on the actual test setup, a ramp input is provided on the power pedal and the vehicle is allowed to accelerate under the influence of dynamometer inertia load only. Based on the results, the most influential parameter on the maximum engine torque is the injection pressure. The maximum predicted engine mean brake torque at 60 bar injection pressure is about 120 Nm. The second influential parameter is the injection duration, where the maximum predicted engine brake torque is about 100 Nm. Both parameters are related to the controlling amount of the fuel-injected, which affected the amount of energy released into the cylinder. The third influential parameter is the ignition timing, where the maximum pressure predicted is closed to 70 bar. It can be concluded that the magnitude of brake torque is sensitive to the amount of fuel supplied for combustion. This comprehensive model is suitable for parametric analysis regardless of the expensive computing time

Radiotherapy dosimetry and the thermoluminescence characteristics of Ge-doped fibres of differing germanium dopant concentration and outer diameter

We examine the influence of elevated dopant concentration on the thermoluminescence characteristics of novel Ge-doped silica fibres. Basic dosimetric characteristics of the TL media were obtained, including linearity, reproducibility, energy dependence, fading, minimum detectable dose and glow curve analysis, use being made of a 60Co gamma irradiation facility (mean energy 1.25 MeV) and an electron linear accelerator producing photons at an accelerating potential of 6 and 10 MV. The 6 mol% Ge-doped fibres were found to provide TL response superior to that of 8- and 10 mol% Ge-doped fibres, both for fibres with outer diameter of 241 µm and 604 µm. Concerning reproducibility, obtained under three different test conditions, at <10% the 6 mol% Ge dopant concentration was observed to provide the superior coefficient of variation (CV). In regard to energy dependence, the 10 mol% Ge doped cylindrical fibres produced the largest gradient values at 0.364 and 0.327 for the 241 µm and 604 µm diameter cylindrical fibres respectively and thus the greatest energy dependency. Measured 33 days post irradiation; the 6 mol% Ge doped cylindrical fibres showed the least TL signal loss, at 21% for the 241 µm cylindrical fibre and <40% for the 604 µm cylindrical fibres. The results also revealed that the 6 mol% optical fibres provided the lowest minimum detectable dose, at 0.027 Gy for 6 MV photon beams. Evaluations of these characteristics are supporting development of novel Ge-doped optical fibres for dosimetry in radiotherapy

Single Hole Direct Injector Simulation Validation and Parametric Sensitivity Study

This paper presents a parametric study conducted on electronically controlled solenoid direct fuel injector running on compressed natural gas. The purpose of the study is to identify the influential injector parameters on the output mass flowrate. These injector parameters are to be optimized in the next stage of the study. The parametric study is conducted using zero-dimensional, first principle injector model, which consist of electromagnetic, mechanical and flow sub-models. In the current study, seven (six input and one output) parameters have been analysed which are the injection pressure, injection duration, nozzle diameter, armature mass, the input voltage, spring constant and the output mass flow rate. Each input parameters are varied in the prescribed range based on the literature. Based on the study, the most influential parameters (in rank) are the nozzle diameter, the armature mass and the injection duration. The input voltage, the injection pressure and the spring constant were found to have no impact on the injector mass flow rate based on the values of the parameter’s sensitivities. Based on the results, the potential parameters to be optimized are identified

The persuasiveness of celebrity Muslim preachers on social media: the ELM perspective

As new media and communication technology evolve, it has revolutionised how Muslim preachers convey da’wah to their fellow Muslims. Social media platforms allow Muslim preachers to connect with their follower and create da’wah messages using various tools such as reels, live streams, and hashtags. Some preachers have become instant celebrities, with millions of followers who are willing to share and repost their content. To what extent though, are their messages persuasive? Accordingly, four hypotheses were predicted for the study based on the elaboration likelihood model (ELM). This study is quantitative, with a cross-sectional online survey design. The survey instrument was distributed among university students who follow celebrity Muslim preachers on social media (N = 423). PROCESS macro was used to test the mediating and moderated mediation model (model 4 and 7). This study did provide some support for ELM; argument quality predicted both belief in da’wah messages and intention to share. Belief also mediated the relationship between argument quality and intention to share. However, personal relevance did not moderate the relationship between argument quality and intention to share, through belief. Implications of these findings on ELM and the persuasiveness of online messages among Muslim social media users will be deliberated

Histopathological and cholinesterase changes in the gills of Clarias gariepinus as a result of cadmium exposure

Aim : The cholinesterase (ChE) based inhibition and histopathological studies from fish were investigated and represented in this study to develop as one of the great potential biomarkers for heavy metals monitoring. Methodology : In this study, the histopathological study of gills were observed a under microscope. The capability of ChE extracted from the gills of Clarias gariepinus was assessed for declining Cd. ChE was purified through affinity chromatography and continued with the optimisation and inhibition study (IC50) of cholinesterase. Results : Histopathological study of gills was carried out and several changes such as aneurysm, necrosis and lamella fusion were noted. Purification fold obtained from purified enzyme was 1.15 with 30% a yield specific activity 20.726. The optimum temperature for purified AChE was 35°C along with acetylthiocholine iodide (ATC) as a preferable substrate that had the highest Vmax value of 0.5452 U mg'1 and the lowest Km value of 0.0311 mM. The optimum pH was observed to be 10 of Tris-HCl as a medium. Meanwhile, the IC50 of cadmium was 6.808 mg ľ with R2 value of 0.9532. Interpretation : The result of the study can be used as a tool for further developing a biomarker for the detection of heavy metals in aquatic ecosystems. In addition, the baseline data provided can also be used for designing a kit, which would give rapid and accurate result

The effect of computer software interaction on students cognitive abilities enhancement: the case of engineering educators’ perspective

In this digital age, the deployment of modern technology in the workplace to mitigate global challenges has become paramount. Therefore, the academic program, as accredited by the regulatory and accreditation bodies, is to ensure the production of quality industry-ready engineering graduates. These products are expected to be technology savvy and proficiently skilled in using computer software (CS) for productivity towards engineering activities. Unfortunately, there exists a gap in the quality of the graduates produced by tertiary engineering institutions in the developing world. This gap can be associated with the lack of computational thinking (CT) skills to meet the industry needs in this age of IR 4.0. Therefore, the paper reports the engineering educators' perceived contributions and gains achieved while employing computer software in the course of instruction towards the cognitive ability enhancement of the engineering students. It provides an in-depth exploratory inquiry into the deployment of CT and its impacts in engineering education while focusing on its integration at what level in the course of study. The research follows a phenomeno-graphic research approach explored the experiences of engineering educators from different engineering disciplines in the higher education institutions, namely chemical, civil, electrical, and mechanical engineering, to gain valuable insights. Data collected through a semi-structured, in-depth interview was coded using NVivo 12 CAQDAS and analysed for relevant themes. The findings indicate a significant potential benefit of enhanced cognitive abilities leading to the development of special knowledge, generic intellectual abilities, and personal attributes. In addition, the integration of CS should be the focus of instruction at the most appropriate level of study to allow for considerable exposure to CS to achieve the desired learning outcome. These findings have direct implications on the engineering educators and students, engineering faculties, and other stakeholders

Patient pathways for cardiovascular diseases in Malaysia and the Philippines: a systematic review

Background: Cardiovascular diseases (CVDs) are the leading cause of premature mortality in the world and are a growing public health concern in low- and middle-income countries (LMICs), including those in South East Asia. Their management requires coordinated responses by a range of healthcare providers, which should preferably be based on knowledge of the national context. We systematically review evidence on the pathways followed by patients with CVD in Malaysia and the Philippines to understand patient journeys, along with the barriers at each stage. Methods: We searched seven bibliographic databases and grey literature sources to identify material focused on the pathways followed by patients with CVD in Malaysia and the Philippines, and performed a narrative synthesis. Results: The search yielded 25 articles, 3 focused on the Philippines and 22 on Malaysia. Most articles were quantitative analyses that focused on hypertensive patients. Three examined secondary prevention post myocardial infarction, and one each examined acute myocardial infarction, heart failure, and atrial fibrillation. Reported barriers reflected capability (knowledge of behaviours to achieve control or the capacity to conduct these behaviours), intention (attitudes or motivations toward the behaviours to achieve control), and aspects of the health care system (availability, accessibility, affordability and acceptability of services). Conclusions: There are large gaps in our understanding of patient pathways in Malaysia and the Philippines that limit the development of evidence-based strategies to effectively address the CVD burden in South East Asian countries and in LMICs more broadly. Addressing these evidence gaps will require longitudinal mixed-methods studies following patients from initial diagnosis to long-term management.</ns3:p