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Electromyography (EMG) signal is an analysis of electrical signals generated during muscular contractions that have been used to measure and record electrical muscle activity usually applied for medical tests. In this research EMG signal is used to; (1) evaluate muscle activations on different gender during prolonged sitting task; (2) investigate the influence of various types of exercise during prolonged sitting on muscle activation and (3) proposed the best exercise that can help to prevent low back discomfort. Twenty subjects (10 males and 10 females) were recruited from undergraduate engineering student’s education background in UniMAP with age ranging between 20 to 24 years old. The subject must be asymptomatic back pain, normal BMI and right-handed. . Three different types of sitting, one hour per sitting were done by each subject in order to reach the goals of this study. First sitting (sitting without exercise) was conducted while second and third sitting (sitting with exercise) were done in order the investigate the effectiveness of the exercises. Two different types of exercise were performed in second and third sitting, both of exercises were chosen from Mc Kenzie’s exercise. EEGOTM sport device were used to record the EMG signal from four types of muscles which are Erector Spinae, Latissimus Dorsi, Internal Oblique and External Oblique. By comparing the Root Mean Square (RMS) values from EMG signals muscle activation during prolonged sitting and the effectiveness of performing the exercises have been evaluated based on RMS values. As the results, muscle become deactivate during prolonged sitting. The best exercise to reduce back pain discomfort is exercise type 1 (Seated Lumbar Exercise) and it is recommended to perform this exercise regularly to reduce the risk of getting hazardous disease due to prolonged sitting. Keywords: Prolonged sitting, muscle activity, exercises on prolonged sitting

The point of this investigation was to decide the hereditary inconstancy and break down the connection between four faba bean cultivars and six promising lines utilizing inter simple sequence repeats (ISSR) markers. Faba bean genotypes were gathered by their resistance to the bean yellow mosaic virus infection. With the acquired band registration, a paired data matrix was built to perform the comparing statistical analysis. The used ISSR markers created 148 fixed and repeatable bands, of which 75 were polymorphic. The values of resolution power (Rp), polymorphic information content (PIC), and marker index (MI), uncovered that primer ISSR-14 was the most effective to break down hereditary changeability with estimations of 5.8, 0.80, and 6.40, respectively, followed by primers ISSR-6 and ISSR-18. Genetic distances swayed somewhere in the range of 0.78 and 0.91, and checked the groupings saw in the dendrogram, which demonstrates high change at the degree of DNA among the investigated genotypes, watching six characterized gatherings as indicated by UPGMA examination. In the examination of fundamental segments, the enrolled groupings were dictated by the source of the origin of the gathering. The utilization of ISSR markers was effective to describe at the degree of DNA the evaluated bean genotypes, showing the presence of inconstancy, the recognized differentiating promotions can be used in hereditary improvement projects planned for settling the requirements of the producers.

Occupational musculoskeletal disorders (MSDs) are quite common among industrial workers. Repetitively lifting, bending, pushing, pulling and standing are the major causes to the occupational diseases. The aim of this study is to investigate the occupational musculoskeletal disorders (MSDs) among industrial workers in Malaysia. Data for this study was collected via Science Direct, Google Scholar, IEEE Explore Digital Library, and Scopus for the analysis to the industrial workers in various Malaysia industries from 2010–2019. The results showed manufacturing industry had the highest MSD cases where 40 manufacturing industries were reported in literature. For the body movements, 59 lifting movements were reported and was the most common movement used by the workers to perform their task which might lead to the injuries of body parts particularly on lower back and shoulder. Appropriate intervention is needed to tackle the MSD issues among the workers.

Muscle is one of the important parts of the body as it made up from a bundle of fibrous tissue. The effects of fracture mechanisms of the bone are been studied related with the existing of muscle layer. In order to establish cortical bone with muscle layer, the structure of the base must be relevant and efficient. Therefore, finite element modeling method is an alternative way to study the effect of human fracture mechanisms with and without muscle layer. The aim of this study is to develop two dimensional (2D) model of human cortical bone and muscle layer in linear elastic fracture mechanics (LEFM) and elastic plastic fracture mechanics (EPFM) by using ANSYS APDL applied on three-point bending test. Other than that, Stress Intensity Factor (K) and Strain Energy Release Rate (J-Integral) were analyzed on both 2D models which are cortical bone layer and cortical bone with muscle layer. Two methods were used to evaluate the values of K which are Displacement Extrapolation Method (DEM) and Constrained Integration (CINT) method. The experimental values then been compared with two theoretical expressions for validation purposes. By referring to the values of error for K and J-Integral values in both methods, it is proved that by using CINT method, the model produced smaller error and higher efficiency. By comparing the two models, cortical bone with muscle layer resulted lower K and J-Integral values. It can be concluded that layer of muscle on the cortical bone gives an impact on the crack tip that allow the growth of the crack.

Traditional archery is becoming popular and has attracted many people at different age level to acquire skills and finally participate in competitive games. It differs from modern recurve archery where it could not rely on equipment for accuracy and stability. It depends on the skilled developed by the archer and adaptability to the environment for competition. Technique of archery shooting was written in many books and may require investigation to confirm their effect on performance of an archer. Therefore, this study aims to investigate the effect of arm posture and bow’s grasping techniques on the traditional archer’s shooting performance (higher score and minimal distance from bulls eye to the location where the arrow hits the target). Four experienced archers performed 5 m indoor shooting and their movement was recorded using motion capture system. The Square grasping technique resulted in more higher scores and minimal distance as compared to the other technique. Overall, the arm posture angle, Φ, did not influenced the shooting performance, except for the Oblique grasping technique.

In recent years, there has been a proliferation of technology and sport science utilized within an athlete’s physical activity and exercise. This study aims to assess the effectiveness of two strength and conditioning exercises, namely, a customized free-weight exercise and plate-loaded machine exercise, on the lower limb muscle activities of the amateur high jumpers. Six amateur high jumpers were divided into two groups, a customized free-weight group and plate-loaded machine group (control group) and performed exercises as instructed by the coach. The EMG signal of the Rectus Femoris and Bicep Femoris muscles were recorded during the exercises. Metronome was used to control the speed of the exercise and it was standardized for all subjects. The harmstring’s cable pull exercise (customized free-weight) triggered Bicep Femoris more compared to the leg curl exercise (plate-loaded exercise). Similarly, in the case of Rectus Femoris muscle, the front squat exercise (customized free-weight exercise) triggered higher muscular activities compared to the leg extension exercise (plate-loaded exercise). In conclusion, the customized free-weight exercise has indicated higher muscle activities compared to the plate-loaded exercise.

Biometric authentication is a recognition of individual according to their unique physiological and behavioural characteristics. Recently, the application of biometric is the most trending in cyber security technology such as fingerprint, facial recognition, and voice recognition. However, these biometrics have their own drawbacks which allow the unauthorized party to cybercrime and the number of cases is also increased. To encounter this kind of problem, the previous researchers proposed brain signal or electroencephalogram (EEG) as biometric trait. EEG is an electrical activity recorded via non-invasive method using electrode placed on the scalps and measured as voltages. EEG is chosen by the researchers as biometric module because EEG hold its own unique characteristics and more robust against the cybercriminals. This paper presents a review of the EEG-based biometric studies and research. The previous research was reviewed based on their signal acquisition, pre-processing, feature extraction and classification. The general knowledge of EEG and the basic operation of biometric authentication also discussed in this paper. The recent studied and research is chosen with various proposed method respect to the better performance rate. In addition, the deep learning in biometric authentication is found to be the popular among the researchers for classification step because more robust and automatically extracted feature within the network.

Objective. The aim of this study was to investigate the effects of surface stiffness on multisegment foot kinematics and temporal parameters during running. Methods. Eighteen male subjects ran on three different surfaces (i.e., concrete, artificial grass, and rubber) in both heeled running shoes (HS) and minimal running shoes (MS). Both these shoes had dissimilar sole profiles. The heeled shoes had a higher sole at the heel, a thick base, and arch support, whereas the minimal shoes had a flat base sole. Indeed, the studied biomechanical parameters responded differently in the different footwear during running. Subjects ran in recreational mode speed while 3D foot kinematics (i.e., joint rotation and peak medial longitudinal arch (MLA) angle) were determined using a motion capture system (Qualysis, Gothenburg, Sweden). Information on stance time and plantar fascia strain (PFS) was also collected. Results. Running on different surface stiffness was found to significantly affect the peak MLA angles and stance times for both HS and MS conditions. However, the results showed that the joint rotation angles were not sensitive to surface stiffness. Also, PFS showed no relationship with surface stiffness, as the results were varied as the surface stiffness was changed. Conclusion. The surface stiffness significantly contributed towards the effects of peak MLA angle and stance time. These findings may enhance the understanding of biomechanical responses on various running surfaces stiffness in different shoe conditions.

Fractional differential equations have been applied to model physical and engineering processes in many fields of science and engineering. This paper adopts the fractional-order Chelyshkov functions (FCHFs) for solving the fractional differential equations. The operational matrices of fractional integral and product for FCHFs are derived. These matrices, together with the spectral collocation method, are used to reduce the fractional differential equation into a system of algebraic equations. The error estimation of the presented method is also studied. Furthermore, numerical examples and comparison with existing results are given to demonstrate the accuracy and applicability of the presented method.

Biodegradable polymers, especially bacterial synthesized polymers, have gained great attention and interest due to the concerns raised regarding the accumulation of petrochemical plastic wastes in the environment. It is known that biodegradable polymers have advantages such as being biocompatible, biodegradable, natural, renewable and have similar mechanical properties compared to conventional polymers. Poly(hydroxybutyrate) (PHBs) are biodegradable polyesters produced naturally by bacteria. PHBs are highly crystalline polyester, which are brittle and prone to thermal degradation during processing. In the past, attempts have been made to reduce the degree of the brittleness of the PHB by copolymerization with hydroxyhexanoate (HHx) or hydroxyvalerate (HVx) co-monomers. Among PHB copolymers: poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHB-co-HHx), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) have improved the flexibility and mechanical properties more than other PHBs. This chapter aims to emphasize the potential on the compatibilization of biodegradable polymer blends with the presence of maleated compatibilizers derived from the host or guest polymers.

In this paper, we present a class of approximating matrices as a function of a scalar parameter that includes the Davidon-Fletcher-Powell and Broyden-Fletcher-Goldfarb-Shanno methods as special cas...

The current study drives at identifying the environmental and economic impacts of rice loss. The analytical method is used to extract the research hypotheses and hypotheses will be tested through the analytical study on rice grains and the rice straw and their losses in the period 2000 to 2015. The development of area, productivity, and production of rice grain in Egypt are analyzed in the same period. Results of study indicate at testing hypotheses through the statistical analysis that the reddens (acre) area of rice in Egypt has decreased to register 0.42% average annually. Productivity of rice grains in Egypt has decreased to represent 0.25% tons/per year with shortage rate 0.617% of year average. It is evident that rice production is decreasing annually with 63.000 tons/per year and shortness rate 1.08% of year average. The loss of rice grains has developed in Egypt to reach 9065 thousand tons annually i.e. 7.35% of the year average; taking into consideration that the price per one ton of rice grains in 2015 has been 3100 pounds. Regarding the productivity of rice straw, it is decreasing registering 0.0028 tons/per year and shortness rate 0.128% of year average. The rice straw production in Egypt is decreasing, registering 33.9 tons/per year and shortness rate 1.05% of year average; taking into consideration that the utilized amount of rice straw in Egypt represents 45% of the produced amount of the straw. Results conclude that there exists a significant statistical relationship between the cultivated area of rice and the amount of loss on the Republic of Egypt’s level. The study recommends that Ministry of Agriculture should focus on establishing more research in agricultural loss, setting also a standard accurate approaches for estimating this loss and providing the necessary accurate data concerning the involved information of the loss estimation. There should be also coordination between Ministry of Agriculture and the State Agency for Environment Affairs to combat rice straw burning, moving and storing it instead to encourage investment in field of recycling rice straw.

The purpose of this study is to understand the influence of four grasping techniques recommended by Saracen Archery and associated forearm muscles activation on traditional archer’s shooting performance. Each archer has shot 6 arrows in each grasping technique to the target, EMG activities of muscle Flexor Digitorum Superficialis (MFDS) and muscle Extensor Digitorum (MED) were collected in bow arm during aiming phase. The shooting performance was indicated by the distance from arrow hitting point on the target to the bull’s eye. The results revealed that each subject has specific grasping technique to obtain the best shooting performance. The grasping technique that generated the best performance is not as recommended by Saracen Archery. All subjects indicated that the best shooting performance was obtained when MED activated more than MFDS.

Previous studies have examined the role of arm swing for various types of jumping technique, but none have been found to study about the gender differences in term of the role of arm swing on forward and backward jump. This study aimed to compare the jumping performance between male and female for forward and backward jump. Seven male and seven female subjects performed four trials of forward and backward jump with (FJA, BJA) and without arm swing (FJ, BJ) respectively. Qualisys Track Manager System, EEGO Sports, Visual3D and MATLAB software was used to record and analyze the performance. According to the result, the triceps brachii muscle is the most active muscle compared to other muscles during jumping. The normalized vGRF showed significant correlation with jump height when jumping forward and backward (p

This study investigated the effect of carrying unstable load on thoracic kinematics while walking on a curved path. Three-dimensional spinal kinematics were defined as the rotations between thoracic and the Virtual laboratory coordinate system (Tho/Virtual lab) which consisted of lateral bending (LB), flexion/extension (FE) and axial rotation (AR) in the frontal plane, sagittal plane and transverse plane, respectively. Eight healthy young adults (4 males and 4 females) performed loads carrying and walking on one meter radius curved path. Spinal kinematics was determined at the left leg heel strike and just before the right toe off during the curved path walking. As a result, a significant main effect of load intensity was found only on FE of (Tho/Virtual lab) at both left leg heel strike and right leg toe off. The study concluded that an increase in the load intensity of unstable load from 10% of body weight likely to generate more thorax extension.

This paper reports on the comprehensive characterisation of heat treated kenaf fibre (KF) and its composites. The kenaf fibres were modified by heating for 2.5–12.5 h inside a drying oven. Heat treatment produces an increase in the crystallinity index and fibre strength of KF. The highest value of KF strength was recorded by applying heat treatment of 10 h on KF. The heat treatment results in the partial removal of impurities/extractives on the KF surface which is detected by scanning electron microscopy and X-ray photoelectron spectroscopy. Atomic force microscopy results signify the decrease of roughness, the increase in peak area density and the increase of the adhesion force on the surface area of heat treated KF. The effect of the heat treatment in enhancing the interface bonding characteristics between the KF and unsaturated polyester matrix can be reflected by the interlaminar shear strength (ILSS) and dynamic mechanical analysis value of the composites. The flexural properties of the compo...

A compression-molded green composite material comprising of bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] and short kenaf fibers (KF) was prepared in the present study. Accordingly, P(3HB-co-3HHx) was produced by the Cupriavidus necator Re2058/pCB113 using the palm oil as the sole carbon source, while the polyhydroxyalkanoate (PHA) copolymer with ∼99% purity was recovered from the bacterial cells using a newly reported solvent-free biological recovery method. Experimental results showed that P(3HB-co-3HHx) containing 30 wt % KF possessed the highest flexural strength and similar or better comparable mechanical performance compared to that of the low density polyethylene (LDPE), LDPE/KF composites and high density polyethylene (HDPE). Water absorption and soil burial tests were also performed to evaluate the durability of the P(3HB-co-3HHx)/KF composites. As compared to that of the pristine P(3HB-co-3HHx), it was determined that P(3HB-co-3HHx)/KF composites demonstrated higher water absorption percentage and showed higher percentage of weight loss during the soil degradation study. Burkholderia sp., Streptomyces sp., Amycolatopsis sp. and Streptacidiphilus sp. that involved in the biodegradation of P(3HB-co-3HHx)/KF composites during the soil degradation study were successfully isolated and characterized. These species had the capability to degrade the composite material in vitro.

The hygrothermal effect on unsaturated polyester composites containing 30% by volume of untreated and alkali treated nonwoven kenaf fiber along with neat resin have been studied. The kinetics of water uptake was investigated by immersing neat resin and composites at room temperature, 60°C and 90°C. Alkali treatment significantly reduced the water uptake and the diffusivity of composite at all aging temperatures; thereby the alkali treated kenaf fiber composites showed better durability of flexural properties. Elevated temperatures aging promoted the severe degradation of samples, and subsequent drying could not restore the flexural properties.

During the sedimentation process, the acoustic impedance transfer function of the liquids through which the pulse propagates has variable acoustic impedance. This acoustic impedance that characterizes a liquid during centrifugation is determined by the pulse–echo configuration results in conjunction with the subsequent experimental results. The system transfer function obtained in this fashion has been shown to agree with a direct measurement of the same function in a reference set-up. Based on laboratory experiments and the derived model, determination of separation efficiency with a high accuracy range of measurements is produced. The value of having a model of this type for a complete system is that one can then examine in detail how changes in the transfer function of the medium affect the system performance; estimates of the effects of system changes can also be made without performing costly experimental validation studies.

FSPL and 2-Ray models are inaccurate to be used in conjugation with foliage models to predicted total path loss in vegetation environments and it has (38.20% and 65.74%) MPAE.The path loss model based COST235 and FSPL was the best performance to the empirical measurements, but it's still not optimum due to that the MAPE was 10.69%.New empirical path loss model (LRCFM) for mango greenhouse has MAPE about 2.75% as compared to other models. Signal propagation losses in protected environments are investigated using wireless sensor networks (WSNs) based on the IEEE 802.15.4 standard of operating frequency, 2.425GHz. In this research, various empirical measurements were conducted to examine the effects of each part of a tree on path loss using different transceiver heights. A new linear path loss regression curve-fitting model (LRCFM) was derived based on the regression technique of computing the total path loss inside the greenhouse environment. The greatest vegetation effects appear within 1.5m tree height; in this research, this height was adopted to study and analyse vegetation models in a mango greenhouse. This research proves that path loss prediction based on free space path loss (FSPL) and two-ray (2-Ray) propagation models is inaccurate in predicting loss in certain environments, as these approaches are simplistic and optimistic. Thus, most known foliage models used in conjugation with FSPL and 2-Ray are inaccurate in predicting the total path loss in a greenhouse environment. The analytical and empirical results prove that the new derived model, the LRCFM, is the best candidate compared to other foliage models. The mean absolute percentage error (MAPE) of the total path loss based on the new LRCFM model was 2.7% compared to the 10.69% of the well-known models.

Currently, there is a significant drive to switch to more sustainable and renewable materials, whilst still reducing weight and cost and maintaining reliability. In addition, with some renewable materials, end-of-life vehicle issues are more easily addressed because the materials are biodegradable or easily recycled. Natural fibres such as flax fibre (FF)have several advantages that have made them particularly attractive to the automobile industry. These include relatively good mechanical strength, low density better thermal and acoustic insulation and low cost. The aim of this study was to produce optimised Nonwoven Flax Fibre Reinforced Acrodur (NWFA) biocomposites. Response surface methodology (RSM) was employed to study the effect of processing conditions such as moisture content, curing temperature and curing time on flexural strength and modulus. The optimized conditions was analyzed using Analysis of Variance (ANOVA) and the optimized value for the maximum flexural strength of NWFA biocomposites was found at 25% moisture content, 1700C curing temperature and 180 seconds curing time. Maximum flexural strength and modulus of 44.83 MPa and 4.70 GPa were attained. From the analysis of variance (ANOVA) technique, namely the Box–Behnken method, curing temperature significantly affects the strength of NWFA biocomposites, followed by the moisture content and curing time. The P-value of the model of the experiment is less than 0.05 and the determination coefficient (R2) is nearly 1 suggesting that the model is significant and implies on the precision and processability in the production.

Mobile Ad Hoc Network (MANET) is a set of mobile nodes that communicate with each other to configure an immediate network without utilizing any of infrastructure, the centralized access point or centralized administration in multiple hop manner. There are a lot of routing protocols have been proposed in MANET which are different from each other in the performance and the mechanism. Therefore, the performance study of those protocols in different scenarios is needed. This paper presents the performance comparison between Dynamic Source Routing (DSR), Ad hoc on demand distance Vector Routing (AODV) as reactive routing protocols and Destination Sequenced Distance Vector (DSDV) as a proactive routing protocol to precisely determine which protocol is more effective. Network Simulator (NS) version 2.35 has used to simulate and evaluate the performance of these protocols in terms of the packet delivery ratio, average throughput, average end-to-end delay, and packet loss ratio with respect to the variable number of nodes.

The study aimed to asssess the effect of simulated leg length discrepancy (LLD) to the gait variability. A total of 10 normal subjects walked at self-selected normal walking pace with simulated LLD of 0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 cm on 3m walkway with embeded force plates. The simulated LLD were applied on the left leg in a randomly selected order. Additionally, the subjects performed walking with and without additional 2 kg of carrying backpacks load. The Centre of Pressure (CoP) was computed using the ground reaction forces and moment collected from the two force plates. The standard deviation of anterior-posterior and medial-lateral COP displacement was used to determine the gait variability. In conclusion, changes on the LLD height led to an increases of gait variability which indirectly affect a person’s stability during walking.

Biobased toughened thermosetting polymer blend was prepared by incorporating epoxidized soybean oil (ESO) into a petroleum-based epoxy (DGEBA) in different composition ratios. The mechanical properties (tensile and flexural tests) of the ESO/DGEBA thermoset blends were determined. Thermal properties of the blends were characterized using thermogravimetric analysis. The result showed that, the tensile and flexural properties decreased with increasing of ESO content. However, a slight increase in the strength properties was observed at 10% of ESO content. A significant enhancement in impact strength proves the role of ESO acting as a plasticizer in the blends as well as improve the toughness properties of ESO/DGEBA thermoset blend. As the ESO content increase, the thermal stability of ESO/DGEBA thermoset blend has decreased might be due to reduced cross-linking density of the epoxy network. Further investigations on morphological properties were also done to correlate the mechanical properties of ESO/DGEBA thermoset blend.

This paper reports on comprehensive characterization of wettability and interfacial properties of kenaf fibers (KF) and its unsaturated polyester (UPR) composites fabricated by resin transfer molding (RTM). KF were chemically modified by immersing in 6% NaOH concentration for 1, 2, 3, 4, and 5 h to enhance the interaction between KF and UPR. FTIR spectral data showed the chemical changes in KF after treatment which induced the modification of physical and wettability characteristics of KF. The changes in crystalinity index (CrI) and thermal stability of KF content were analyzed using X-ray diffraction (XRD) and thermogravimetry (TGA) techniques, respectively. Scanning electron microscope (SEM) shows a cleaner KF surface upon KF treatment and atomic force microscopy (AFM) signify an increasing in available fiber–matrix specific contact area. Wettability of KF was investigated by means of surface energy measurement using Washburn contact angle principle via Owens–Wendt–Rabel–Kaelble (OWRK) method. Surface energy was found to increase with longer soaking time. The effect of soaking time of alkaline treatment in enhancing the interface bonding characteristic between the KF and UPR matrices can be reflected by the ILSS value of the composites. The highest value of ILSS was recorded by 3 h treated KF composite. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

In the present study, mechanical and water absorption properties of the nonwoven kenaf fiber (KF)/unsaturated-polyester composites manufactured by resin transfer molding were investigated. Nonwoven KF mats with an aerial density of 1350 g/m2 were treated with a 6% NaOH solution for 3 h. The influence of the fiber treatment on the properties of the composites was investigated with Fourier transform-infra red (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM), and dynamic contact angle technique (DCAT). Mechanical properties measurements were conducted via determination of flexure and fracture toughness. A general trend was observed whereby alkalized KF composites gave superior mechanical properties compared to as-received KF composites. The XRD and DCAT results indicated an enhancement of the crystallinity index and surface energy of the alkali-treated KF. SEM and AFM of the treated KF showed the removal of impurities and a reduction of roughness on the KF surface with alkalization. Water immersion induced a drastic loss of the mechanical properties of the composites albeit better retention of properties was observed in the case of alkalized KF composites. The fracture surfaces were inspected by SEM which confirmed the quality of the interface. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

This paper focuses on the study of the effect of chemical treatments of fibres by alkalization on the flexural and impact properties of epoxy matrix composites reinforced by kenaf fibre (KF) produced via resin transfer moulding (RTM) technique. The reinforcement consists of KF nonwoven fiber mat fabricated using needle punching method. Prior to punching process, KF are subjected to alkali treatments with Sodium hydroxide (NaOH) at 3, 6 and 9% for a period of 3h at room temperature. The composites were reinforced with kenaf nonwoven mat at 40% by volume. Effect of alkaline treatment concentration to wettability of KF towards epoxy resins are measured by means of contact angle and surface energy analysis. Influences of alkaline treatment on the flexural properties are studied to determine the optimum conditions of alkaline treatment. As concentration of NaOH in alkaline treatment increased, the experimental results show that the flexural properties of composites increases. For 6% NaOH treatment, the flexural strength and flexural modulus improved by 7.88 MPa to 81.38 Mpa and from 4.79 GPa to 5.41GPa compared to untreated fibre composites. However, as the concentration of NaOH increase to 9%, the bending properties reduced significantly.

The interfacial and mechanical properties of nonwoven kenaf fibre (KF) reinforced acrylic based polyester composites fabricated by resin impregnation process were studied. Different types of treatments were applied to KF, i.e. alkali treatment with NaOH at concentration of 6% (at room and elevated temperature of 60°C) and heat treatment at 140°C for 10h. FT-IR spectral data showed the chemical changes in KF that induced the modification of physical and interfacial characteristics of KF. Alkali treated KF was found to have smaller diameter but higher density. Significant increase in the crystallinity index of treated KF contributed to the improved fibre strength. AFM analysis revealed the exposure of cellulose micro-fibril network and the increase in the area peak density value of treated KF. Surface energy of KF and surface tension of acrylic resin were obtained through Owens–Wendt–Rabel–Kaelble (OWRK) equation and Du Nouy ring approach, respectively, for the interfacial properties determination. The improved wettability of alkali treated KF was confirmed as higher surface energy of the fibre was recorded exceeding the surface tension of acrylic resin, thereby imparting better flexural properties and dynamic mechanical behavior, but conversely deteriorating the fracture toughness of the reinforced composites. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

In the pursuit of green and more sustainable product, natural fibre reinforced composites originating from renewable resources has gained interest in recent years. These natural fibres exhibit good mechanical properties, low production costs, and good environmental properties. However, one of the disadvantages of natural fibre reinforced composites is their high flammability that limits their application in many fields. Within this research, the effect of sodium silicate on the flammability and thermal properties of flax reinforced acrylic based polyester composites has been investigated. Sodium silicate is applied as binder and flame retardant system in impregnation process of the natural flax fiber mats. The addition of sodium silicate significantly improved the flame retardant efficiency but reduced the degree of crosslinking of the composites.

The aim of this research is to present a numerical modeling of crack for human long bone specifically on femur shaft bone under mode I loading condition. Two – dimensional model (2D) of long bone was developed based on past research study. The finite element analysis and construction of the model are done using Mechanical APDL (ANSYS) v14.0 software. The research was conducted mainly based on two conditions that were at different crack lengths and different loading forces for male and female. In order to evaluate the stress intensity factor (KI) of the femur shaft of long bone, this research employed finite element method to predict the brittle fracture loading by using three-point bending test. The result of numerical test found that the crack was formed when the crack length reached 0.0022 m where KI values are proportional with the crack’s length. Also, various loading forces in range of 400 N to 1000 N were applied in an attempt to study their effect on stress intensity factor and it was found that th...

The present work studies the dependence of mechanical properties of kenaf fibre (KF) reinforced acrylic based polyester composites on the processing parameters. Prior to moulding, non-woven kenaf fibre (NWKF) with areal density of 1200 g/m2 was impregnated by acrylic based polyester resin using an impregnation line followed by a post-drying step. The flexural properties of the composites were investigated with respect to changes in impregnation and moulding conditions based on Design of Experiment (DOE) of Response Surface Methodology (RSM). RSM through Central Composite Design (CCD) was applied to develop a model of flexural properties with respect to the combination of processing variables. The mathematical regression models of the flexural properties were derived from the analysis of variance (ANOVA) to determine the model significance. All processing variables in linear terms exhibit significant effect on the flexural strength of the composites. Optimisation of the independent variables to maximise the flexural properties was estimated and verified.The present work studies the dependence of mechanical properties of kenaf fibre (KF) reinforced acrylic based polyester composites on the processing parameters. Prior to moulding, non-woven kenaf fibre (NWKF) with areal density of 1200 g/m2 was impregnated by acrylic based polyester resin using an impregnation line followed by a post-drying step. The flexural properties of the composites were investigated with respect to changes in impregnation and moulding conditions based on Design of Experiment (DOE) of Response Surface Methodology (RSM). RSM through Central Composite Design (CCD) was applied to develop a model of flexural properties with respect to the combination of processing variables. The mathematical regression models of the flexural properties were derived from the analysis of variance (ANOVA) to determine the model significance. All processing variables in linear terms exhibit significant effect on the flexural strength of the composites. Optimisation of the independent variables to maximise th...

Finite element modelling and analysis is an alternative way to study human fracture behaviour in biomechanics field compared to experimental test in laboratory. The aim of this study is to analyse the stress intensity factor (K) and strain energy release rate (J-integral) when three-point bending test and tensile test are applied on a two-dimensional (2D) cortical bone model developed by using finite element software with different applied loads and crack-to-width ratios. Two methods are used to to evaluate the values of K and J-integral which are Displacement Extrapolation Method (DEM) and CINT method. The values then been compared with other theoretical expression done by other researchers for validation purposes. It has been proved that by using CINT method, the error is very small compared to DEM method. As a result, stress intensity factor values increased as crack-to-width ratio increased and strain energy release rate also increased as crack-to-width ratio and loads increased. It can be concluded that finite element analysis can be used to study the fracture behaviour of human cortical bone. Therefore, researchers can easily study the behaviour of cortical bone using simulation instead of mechanical experiment.

Exploring the walking of LLD are clinically helpful in understanding which LLD level contributed to the changes at the upper limb. The aim of this work was to determine which LLD level during single leg stance and double leg stance contributed to the spinal changes. Eighteen healthy male subjects were induced with 0.5 cm to 4.0 cm height of insoles with interval 0.5 cm accordingly and their spine motion during the stance phase was captured by 5 Oqus cameras and evaluated by using Qualisys Track Manager (QTM) software. The effect of LLD height on spinal kinematics were assessed using spinal curvature parameters which are the lateral bending angle at lumbar (LBAL), the shoulder-girdle and pelvic line bending angle (SPBA) and the shoulder-girdle line and pelvic line rotation angle (SPRA). 4 cm LLD height at double stance phase created a relatively larger LBAL when compared with normal walking. The influence of LLD on SPBA and SPRA was very minimal.

This paper presents the comparative study of design efficiency of two different designs of agarwood extracting oil machines by performing using the Design for Manufacturing and Assembly (DFMA) method. The DFMA method was used as it is a well-established technique for improving the efficiency of the product leading to minimizing production costs. It also shortens product development time by reducing the number of components in a product. The study used two different designs of agarwood extracting oil machines as a case study. The result shows that the percentage of the design efficiency of existing design model 1 is 9.25%, whereas it is 15% of redesign. Thus, the redesign model 2 is much better as compared to existing design model 1 in terms of its assembly operation and design efficiency. Therefore, the redesign model 2 is greener than existing design model 1. Therefore, the application of the DFMA method to enhance the development of a agarwood extracting product has been proven to be highly useful in the design work.

One way to accurately diagnose many human diseases is to conduct tests on a sample of blood. These tests are based on analyzing precisely the results of a blood plasma sample free from any other blood cells. This article develops a mathematical model for the separation efficiency of laboratory centrifuge controller. Multi-decay power pulses through a blood sample to determine separation efficiency that provides accurate attenuation measurements. Ultrasonic attenuation measurements were obtained for human blood-plasma of 1 ml volume for concentrations of 20%, 35%, 55%, 80% and 95% plasma by weight. The separation efficiency measurements were obtained for a time period of 5 min divided into 0.5 min. Attenuation measurements for separation efficiency greater than 95% may prove useful for process control to decrease spinning time and power consumption. The data shows the feasibility of producing a separation efficiency of 95% plasma for 0.35 ml of 1 ml blood for 3.1 min. It can be shown that such measurements may prove useful in reducing the centrifugation time with high separation precision.

Stress intensity factor, K and strain energy release rate, G have been obtained by using three point bending test in two-dimensional (2D) model of cortical bone in human thigh segment. The test is done in finite element analysis (FEA) with respect to continuum mechanics approach. The K and G values from the simulation gave almost similar values compared by using an equation established by A. F. Bower. The maximum error was 7.2 % while the minimum was only 1.2 %. From the graph obtained, the K and G values were increased when the ration of crack length and width, a/W of the model increased. In can also be proven that K is proportional to G in linear elastic Mode I model. There is lack of study in continuum mechanics area concerned on the use of numerical analysis of initiation and propagation cracks in human cortical bone. Thus, by using a finite element analysis or conceptual model when attempting to reduce the risk of injury and designing better devices on medical purposes serve as a logical starting point.

Problem statement: In this study, the behavior of small scale fading channel due to a moving sink node of a Wireless Sensor Network (WSN) or moving of surrounding objects is presented. Approach: Specifically, this research introduces the effects of multipath and scattering on the transmitted signal due to mobile sink node with in forest or closed field filled of reflectors and scatters. Signal propagation above the cross canopy suffer attenuation and variance in the strength of the received signal. Results: The density of leaves in the crop changes over tim e thus results in more signal obstacles and attenuation at receiver node. The sink node is considered to be in stationary sta tus or it moves with speed not more than 1 m sec -1 , while the sensor nodes of the WSN is preplanned i n a fixed position. Conclusion/Recommendations: The modeling of pass band transmitted signal fused in Rayleigh fading channel of stationary and moving st atus of a receiver are derived. The fluctuation of RF signal, average received signal level, outage probability and the Doppler shift effects are simulated and a detailed analysis is present. The a ppropriate spatial distribution of the network nodes and the exist of a LOS component will highly necessary between sensor nodes and the sink node in agricultural applications. Indeed power con sumption must well maintain so packet loss due to less power level can be overcome. Best posit ion found is center of the application field of the greenhouse for the sink node in stationary situ ation, while for movement situation the best height of the sink node is to be little above line level of the sensor nodes.