Exploring Psychological Well-Being Among Tahfiz Al-Quran Students: Emprical Study Using Psychoeducation Counseling and Therapy

This study aims to explore mental stress, self-efficacy and coping strategies that contribute to the stability of tahfiz students' mental health. This study is a qualitative study that uses phenomenological methods in psychoeducational group counseling. The respondents of this study consisted of 5 students of Tahfiz School and Malaysian Armed Forces Orphans (STAY ATM) who were 17 years old. Data analysis using content analysis techniques. The results of the study found that the mental stress faced by tahfiz students is caused by parental coercion, military- lifestyle and environmental factors. As a result of the mental stress experienced, emotional changes also occur. In the aspect of self-efficacy, tahfiz students have personal advantages such as being talented in various fields, extroverted, and independent, but their introvert attitude, low self-esteem and not knowing how to manage time are also their weaknesses. From the aspect of coping strategies, tahfiz students have a mature and rational coping strategy in managing the mental stress they face and have a clear future plan. Al Quran approach clearly shows that it can have a positive effect on the mental stability of tahfiz students. The results of this study have positive implications for students, parents, STAY ATM’s and community

Characterization of hybrid yarn/fabrics from of kenaf-kevlar fibers

In this work, new hybridization method used to fabricate different hybrid yarn by using untreated and treated kenaf fiber and Kevlar yarn until development of hybrid fabrics. The hybrid yarn consists of various combination of kenaf and kevlar fiber with the composition ratio of 70% kenaf: 30% kevlar, 50% kenaf:50% kevlar and 30% kenaf:70% kevlar were weaved and also 100% kenaf and 100% kevlar yarns were weaved as the control data to compared with hybrid fabric. The woven of Kenaf-Kevlar composition were carried out by the weaving of hybrid yarn in weft and warp direction. Tensile properties of kenaf fiber, kevlar fiber, hybrid yarn and hybrid fabric were measured by using Universal Testing Machine. Morphology of all fibers-treated and untreated kenaf and kevlar were analyzed by using scanning electron microscopy (SEM). The obtained result showed that 30%Kenaf:70%Kevlar hybrid yarn and fabric has the highest strength (48.511 cN/Tex) and modulus (1815.570 cN/Tex) among the hybrid but its value 70% lower than 100% Kevlar fabric. Both treated Kenaf and Kevlar fibers showed fine surface and light weighted as compared with untreated fibers. The preliminary research results have shown that development of hybrid materials from natural fibers has the potential to be utilized for high performance composite applications

A focused review of short electrospun nanofiber preparation techniques for composite reinforcement

Short nanofibers have been of interest in preparing 3D porous structures, aerosol filters, and nanocomposites. These materials require nanofiber retrieval and application in short form with simultaneous control over aspect ratio. Electrospinning, conventionally, offers minimal control over short nanofiber yield as nonwoven mat is the default configuration of collected sample. High surface area to volume ratio nanofiber, however, can offer new vistas in material design if standardization of short nanofiber preparation practices, offering control over aspect ratio, can be attained. It will provide novel insights into design of tissue engineering scaffolds, filtration membranes, and nanocomposite properties. This work summarizes reported efforts to prepare short nanofiber through mechanical, chemical, material, and operational variables. It aims to provide comparative glance at attempts to control aspect ratio along with pros and cons of the adopted techniques. Lastly, discussion shares generalized conclusions and insights gathered while reviewing material and operational variables adopted for short nanofiber preparation

Modulus Effect on Local Load Distribution for FRP/Steel Bonded Joint

Rehabilitation of piping system has been a major concern in the oil and gas industries. Fibre reinforced polymers (FRPs) have been introduced as an alternative approach and increasingly used in repairing oil and gas pipeline. However, performance of pipeline repair system is decided by its load transfer ability and for FRPs, this led to the debonding issue which has been studied by many researchers. This paper describes a series of double strap shear tests under tensile load to investigate the bond performance between FRP sheets and steel plates. Adhesive failure at the steel-adhesive interface was observed to be the dominant failure mode for both glass fibre reinforced polymer (GFRP)-Steel and carbon fibre reinforced polymer (CFRP)-Steel DSJ due to its higher modulus ratio compare to FRP-adhesive interface. Strain distribution along the bond length shows that GFRP offer larger extension before debonding compared to CFRP. CFRP-Steel DSJ withstand higher ultimate load and possessed better load transfer ability compare to GFRP-Steel DSJ. The load spread throughout the CFRP-Steel DSJ bond length while only 50% of GFRP-Steel bond length were effective. The experimental result shows that the FRP type and bond area of a rehabilitated pipeline need to be taken into consideration during pipeline strengthening

Mechanical behaviour of pin-reinforced foam core sandwich panels subjected to low impact loading

As a light structure, composite sandwich panels are distinguished by their significant bending stiffness that is rapidly used in the manufacture of aircraft bodies. This study focuses on the mechanical behaviour of through-thickness polymer, pin-reinforced foam core sandwich panels subjected to indentation and low impact loading. Experimental and computational approaches are used to study the global and internal behaviour of the sandwich panel. The samples for experimental testing were made from glass/polyester laminates as the face sheets and polyurethane foam as the foam core. To further reinforce the samples against bending, different sizes of polymeric pins were implemented on the sandwich panels. The sandwich panel was fabricated using the vacuum infusion process. Using the experimental data, a finite element model of the sample was generated in LS-DYNA software, and the effect of pin size and loading rate were examined. Results of the simulation were validated through a proper prediction compared to the test data. The results of the study show that using polymeric pins, the flexural strength of the panel significantly increased under impact loading. In addition, the impact resistance of the pin-reinforced foam core panel increased up to 20%. Moreover, the size of pins has a significant influence on the flexural behaviour while the sample was under a moderate strain rate. To design an optimum pin-reinforced sandwich panel a “design of experiment model” was generated to predict energy absorption and the maximum peak load of proposed sandwich panels. The best design of the panel is recommended with 1.8 mm face sheet thickness and 5 mm pins diameter

Damage characterisation of amine-functionalized MWCNT reinforced carbon/epoxy composites under indentation loading

Damage resistance of carbon fibre reinforced composites is crucial parameter to be considered at both primary selection and in-service maintenance stages. High stiffness of carbon-epoxy system and stacked configuration make it susceptible to impact induced brittle damages. Delamination is one such life-limiting damage modes that can severely inhibit load carrying capacity of laminates. Hence to improve the damage resistance of composites demands tailoring tough microstructure and altering brittle damage modes with ductile ones. This work attempted to design damage resistant carbon composites through modification of epoxy matrix with amine functionalized multi walled carbon nanotubes (NH2-MWCNT). Laminates with different nanotube concentrations (0.3, 0.6, 0.9 and 1.2 wt. %) were fabricated to investigate its influence on load bearing capacity, toughness and damage resistance of fibre reinforced nanocomposites. Generally, peak force, displacement and toughness until maximum force improved at all nanoparticle concentrations. Matrix cracking was suppressed owing to optimum cross-linking of nanoparticle with matrix. External damage area increased with nanoparticle concentration although delaminated area, mapped through c-scan, was suppressed up to 27.73%. A combination of higher degree of interfacial interactions, induced by nanoparticles, and energy absorbing microstructure was concluded to be behind improvement in the damage resistance of composites

A review of properties and fabrication techniques of fiber reinforced polymer nanocomposites subjected to simulated accidental ballistic impact

Composite structure experience ballistic or high velocity impact loading during in-flight operations owing to hail, bird and debris strike. In thin laminates, such an impact entails damage resulting from complex interplay of projectile characteristics, composite material properties and environmental conditions. Delamination resistance and energy absorption are two parameters to characterize the ballistic performance of materials in research community. As out of plane properties are controlled by matrix, its microstructural modification is the primary method through which ballistic performance of composites are sought to be improved. High specific surface area nanoparticles are now being used, for matrix modification, to induce nano-scale toughness mechanisms. This paper starts with brief outline of these mechanisms followed by summarizing nanocomposite fabrication techniques and ballistic impact performance of nanocly, graphene, carbon nanotube and other miscellaneous nanoparticle reinforced composites. Finally, it highlights unexplored areas in polymer nanocomposite research with focus on ballistic performance

Hybrid and synthetic FRP composites under different strain rates: a review

As a high-demand material, polymer matrix composites are being used in many advanced industrial applications. Due to ecological issues in the past decade, some attention has been paid to the use of natural fibers. However, using only natural fibers is not desirable for advanced applications. Therefore, hybridization of natural and synthetic fibers appears to be a good solution for the next generation of polymeric composite structures. Composite structures are normally made for various harsh operational conditions, and studies on loading rate and strain-dependency are essential in the design stage of the structures. This review aimed to highlight the different materials’ content of hybrid composites in the literature, while addressing the different methods of material characterization for various ranges of strain rates. In addition, this work covers the testing methods, possible failure, and damage mechanisms of hybrid and synthetic FRP composites. Some studies about different numerical models and analytical methods that are applicable for composite structures under different strain rates are described

Using Finite Element Approach for Crashworthiness Assessment of a Polymeric Auxetic Structure Subjected to the Axial Loading

Polyurethane foams are one of the most common auxetic structures regarding energy absorption enhancement. This present study evaluates the result reliability of two different numerical approaches, the H-method and the P-method, to obtain the best convergence solution. A polymeric re-entrant cell is created with a beam element and the results of the two different methods are compared. Additionally, the numerical results compare well with the analytical solution. The results show that there is a good agreement between converged FE models and the analytical solution. Regarding the computational cost, the P-method is more efficient for simulating the re-entrant structure subjected to axial loading. During the second part of this study, the re-entrant cell is used for generating a polymeric auxetic cellular tube. The mesh convergence study is performed on the cellular structures using the H- and P- methods. The cellular tube is subjected to tensional and compressive loading, the module of elasticity and Poisson’s ration to calculate different aspect ratios. A nonlinear analysis is performed to compare the dynamic response of a cellular tube versus a solid tube. The crashworthiness indicators are addressed and the results are compared with equivalent solid tubes. The results show that the auxetic cellular tubes have better responses against compressive loading. The primary outcome of this research is to assess a reliable FE approach for re-entrant structures under axial loading

Dynamic response of aluminium sheet 2024-T3 subjected to close-range shock wave: experimental and numerical studies

Abstract This present study investigates experimentally and numerically the behaviour of 1 mm thick aluminium 2024-T3 alloy sheets from near field shock waves. A comparison and examination are undertaken with respect to global deformation and plastic damage formation from two different stand-off distances of 4 mm and 50 mm that were exposed to a constant charged mass. A 4-cable instrumented pendulum blast set-up was used to carry out and monitor the blast test. The results of the blast test were subsequently used to simulate the pressure history for different stand-off distances. The simulation involved implementing a user subroutine in ABAQUS/Explicit solver to model non-uniform pressure fields for use in finite element simulation. The results provided a strong alignment of the numerical method when compared with the experimental data. The main outcome of this study is to show the significant effect of the changing damage from highly localised perforation to global deformation when the stand-off distance is changed from 4 mm to 50 mm