bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of Kenaf Filled Unplasticized Polyvinyl Chloride Composites
Authors: Abdrahman Mohd Firdaus , Zainudin E.S.
Published: February 2011

Combination of lignocellulosic fiber with thermoplastic is leading to the new areas of research in plastic composite field. Due to the problem of petroleum shortages and encouragement for reducing the dependence on fossil fuel products, thus increased the people interest in maximizing the utilize of renewable materials like kenaf fiber. By adding optimum natural fiber to thermoplastics could provide some cost reduction to the world of plastic industry as well as to dominance the agro-based industry. With a view to identifying the effect of fiber content and effect of coupling agent in kenaf fiber reinforced unplasticized poly (vinyl chloride) (UPVC) composite on the mechanical properties, the fiber and matrix mixture were mixed with poly [methylene poly (phenyl isocyanate)] (PMPPIC) using thermal mixing process followed by compression molding technique for the composite preparation that required for tensile characteristic (ASTM D638). The fiber loading were 10%, 20%, 30%, and 40% in weight. Since the kenaf fiber and UPVC are chemically different, the compatibility and dispersability of kenaf fiber in UPVC can be improved by lowering the surface energy of the fiber to make it less polar, consequently more similar to the plastic matrix. Generally, PMPPIC act as a bonding agent that facilitates the optimum stress transfer at the interface between fiber and matrix which gives an optimal mechanical performance of kenaf fiber reinforced UPVC composites. Meanwhile, the addition of 30% fiber contents with PMPPIC was successful to enhance the tensile properties and the efficiency of PMPPIC was verified using Fourier Transform Infra-Red (FTIR) spectroscopy.
Mechanical and Thermal Properties of Polyamide 6 Nanocomposite Toughened with Epoxidised Natural Rubber-25
Authors: Navid Nematzadeh , Mat Uzir Wahit , Azman Hassan , Shaya Mahmoudian
Published: February 2011

Polyamide (PA6) is an engineering plastic with wide range of applications and the development in the field of montmorillonite (MMT) filled polymer nanocomposites has resulted in the development of PA6/MMT nanocomposites. However, MMT filled PA6 nanocomposites are notch sensitive and brittle at low temperatures, which posed as a major setback for many of its applications. The main objective of this study is to enhance the toughness of PA6/MMT (100/4) nanocomposites with epoxidised natural rubber-25 (ENR25). The ENR-25 content in the composites ranged from 15 to 30 wt%. The PA6/ENR/MMT nanocomposites were extruded and injection molded into tensile and impact test samples. The addition of ENR25 into PA6/MMT nanocomposites improved the impact strength of the nanocomposites while tensile modulus and tensile strength decreased with increasing ENR25 content. The thermal properties of PA6/ENR/MMT nanocomposites were also investigated via thermal gravimetric analysis (TGA). Both T10% and derivative thermal analysis (DTA) determined the lower thermal stability of PA6/MMT nanocomposites after addition of ENR.
Comparative Study of Fiber Metal Laminates (FMLs) and Aluminum Skins for Polypropylene (PP) Honeycomb Core Sandwich Structure under Low Velocity Impact Loads
Authors: Hazizan Md Akil , Tan C.Y.
Published: February 2011

In this study, the impact responses of sandwich structure with both FML and aluminum skins were compared. The force-time histories from the low-velocity drop weight impact tester were recorded under various impact energies. Energy absorbed from the two types of sandwich structures under various impact energies were also calculated by measuring its initial velocity before impact from a series of recorded high speed camera pictures and force-time histories. Based on results obtained, pure aluminum skins with PP honeycomb core that being impacted by lower impact energies shows higher absorbed energies as compared to FML skins. However with higher impact energies the FML skins shows improvement over the aluminum with higher energy absorption capacity. Damages created were also being characterized under optical microscope for further investigation.
Impedance Characteristics of Electrospun Nylon-6/TiO2 Nanocomposite for Humidity Sensor
Authors: Hosseinmardi Alireza , Keyanpour-Rad M. , Hesari F. Alikhani
Published: February 2011

Resistive relative humidity (RH) sensors were fabricated by nano composites of nylon-6 and titanium dioxide nanopowders. The results indicated that these sensors can be fabricated as a reliable, low cost and fast response instruments. Different percentages of nylon-6 and TiO2 were studied and average diameters of the resultant nanofibers were found the 80 to 120 nm. The nano composite of nylon-6/TiO2 nanofibers was electrospun on the interdigital gold electrode on the glass substrate. It was found that the impedance of the mat ranged from 107 Ω to 102 Ω while the relative humidity was increased from 11% RH and 97.3% at room temperature. Transition electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the morphology of the nano composite.
A New Self Healing Method in Composite Laminates Using the Hollow Glass Fiber
Authors: Nademi Majid , Mozaffari Ali , Farrokhabadi Amin
Published: February 2011

The purpose of the present study is to obtain the least strength reduction and uttermost healing efficiency in a typical [(90/0)/(90/0)Hollow/90/(0/90) Hollow/90/(0/90) Hollow/(0/90)] self-healing laminate. It has been done using a hollow glass fiber (HGF) with a given diameter and an individual method to distribute the HGF in the host laminate. The results of three-point bend flexural strength testing indicated that for the investigated distribution, the inclusion of HGF imparts little reduction in undamaged strength (4%) which is due to the non-integrity of self-healing laminate related to the host laminate. After healing it was found that the laminate had a residual strength of 97% compared to the undamaged control and 100% compared to an undamaged self healing laminate.
Preliminary Review of Biocomposites Materials for Aircraft Radome Application
Authors: Haris M.Y. , Laila D. , Zainudin E.S. , Mustapha Faizal , Zahari Rizal , Halim Zahurin
Published: February 2011

An aircraft radome usually refer to radar transparent, dome-shape structures which protects radar antennas on aircraft from aerodynamic loading, weather as well as impacts from bird strikes. Materials that are used for small aircraft radome usually have low dielectric constant and high toughness. Current composite material using high strength fibers such as glass fiber, carbon and aramid are commonly used in aerospace structures. However, the need for biodegradable materials has prompted the usage of natural fibers. Natural fibers have comparable mechanical properties such as low weight, low cost, renewable and biodegradable. In this preliminary work, comprehensive reviews of biocomposites materials are discussed in term of their properties for the purpose of evaluation for aircraft radome application. The present review will cover five local natural fibers namely bamboo, banana, kenaf, oil palm and pineapple leaf fiber.
Fatigue Delamination Analysis of Composite Laminates with a Central Hole Using Interface Elements
Authors: Hosseini-Toudeshky Hossein , Jasemzadeh A. , Mohammadi Bijan
Published: February 2011

In this paper a solid like interface element along with a fatigue constitutive law is used to study the damage behaviour of holed composite laminates under cyclic loading. For this purpose a user element routine and a material routine was developed include the interface element and to handle the formulation of progressive fatigue damages. The developed procedure is used to predict delamination initiation and growth in mixed-mode condition for a typical composite laminate. The obtained results for damage and stresses are compared with the available results in the literature.
Mechanical Properties of Composite Panels from Rice Husk
Authors: Abu Bakar Nur Afidah , Muhammed Suhaimi
Published: February 2011

The study involving utilization of agricultural residue is gaining attention. This is an attempt to investigate the possibility of producing composite panels from rice husk (RH), an abundant source of agricultural residues. Composite panels were produced by mixing 1mm of rice husk with a commercial binder called urea formaldehyde at different density levels namely 650kg/m3, 700kg/m3 and 750kg/m3. Two types of resin content (10% and 12%) were used. Mechanical strength tests were performed on the panels conforming to British Standard (BS EN 310). Results obtained indicated that the modulus of elasticity (MOE) increased up to 1753.98MPa at 750kg/m3 density level with 12% resin content. Similarly, modulus of rupture (MOR) increased up to 8.08MPa with increase in panel density and amount of resin content. Thus, the potential of producing reasonably good composite panels from rice husk for specific end usage is very promising.
Synthesis of MWCNT-Alumina Hybrid as Composite Reinforcement Using Nickel Catalyst
Authors: Abdul Kudus Muhammad Helmi , Hazizan Md Akil , Mohamad Hasmaliza
Published: February 2011

This work focuses on synthesis of MWCNT-alumina hybrid compound via methane decomposition process using nickel catalyst. The catalysts prepared through in situ process by using nickel salt and aluminium powder which then calcined at 900oC followed by methane decomposition process to grow MWCNT on alumina surface. The Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM) images confirmed the formation of MWCNT with homogenous dispersion on alumina particles.
A Review on the Performance of Adhesive Bonding in Polymer Composite Joints
Authors: Abdul Razak S.N. , Othman A.R.
Published: February 2011

Past and on-going research works on adhesive bonding in composite and sandwich were reviewed. Discussion was emphasized on critical failure mechanisms (e.g. mechanism of peel fracture) to enhance the performance of the bonding. This paper also focused on the application of good adhesive bonding in the application of sandwich structures. Debonding between skin and core is one of the failure mechanisms that should be given more attention in fabrication of sandwich structures. Incorporating fillet in composite bonding is one of the alternative ways to reduce the stress concentration at the edges of overlap length and to produce high peel strength for bonding. Basic understanding of the designs, theories and manufacturing of adhesive bonding were also presented. Several important parameters in the design such as the strain energy release rate (SERR) and formation of fillet also discussed. The analysis of SERR using virtual crack closure technique (VCCT) has also been highlighted to achieve high strength of adhesive bonding, providing the key element for optimization of the delamination resistance in maximizing energy absorption during fracture. Significant challenges or limitations in improving and optimizing the design were also highlighted.
Nonlinear Free and Forced Vibrations of Symmetric Laminated Panels
Authors: Shooshtari Alireza , Razavi Soheil , Bargh Hadi Ghashochi , Sadr-Lahidjani Mohammad Homayoun
Published: February 2011

In this paper, free and forced vibrations of symmetric laminated composite plates are studied analytically by using a perturbation method where the analytical results for transverse displacement are compared with the numerical results. The external force is taken to be harmonic in time and having uniform amplitude.
The Partial Replacement of Halloysite Nanotubes (HNTs) and Precipitated Silica by Recycled Poly(ethylene Terephthalate) Powder on Cure Behavior, Tensile Properties and Morphology of Natural Rubber Composites
Authors: Nabil H. , Hanafi Ismail , Azura A.R.
Published: February 2011

In this article, halloysite nanotubes (HNTs) and precipitated silica were replaced by recycled polyethylene terephthalate powder (R-PET) in natural rubber composites. Five different compositions of NR/HNTs/R-PET and NR/Silica/R-PET composites [i.e. 100/20/0, 100/15/5, 100/10/10, 100/5/15, and 100/0/20 parts per hundred rubber (phr)] were prepared on a two-roll-mill. Comparison of the curing behavior, tensile properties, and morphological characteristics of natural rubber composites was studied. The results indicated that the replacement of HNTs and silica by R-PET decreased the tensile strength, tensile modulus, and elongation at break of composites, but NR/Silica/R-PET composites showed the lower trend than that NR/HNTs/R-PET did. The negative effect of these properties could be explained by the decrement of crosslink density, R-PET is unable to be transferred the stress due to the weal rubber-fillers interactions, and the reducing of ductility of rubber matrix. The curing results revealed that, with replacement of HNTs and Silica by R-PET, the scorch time (ts2) and cure time (tc90) were decreased. Scanning electron microscopy investigation of tensile fracture surfaces conﬁrmed that co-incorporation of NR/HNTs/R-PET would improve the dispersion of R-PET and enhanced the interactions between fillers and NR matrix rather than NR/Silica/R-PET composites.
Mathematical Model for Axial Crushing of Hybrid Square Tubes
Authors: Akbarshahi H. , Sadighi Mojtaba , Shakeri Morteza , Mirzaei M.
Published: February 2011

In this paper, to investigate energy absorption capability of hybrid (metal-composite) square tubes under axial loading, a new theory is proposed based on collapse mode of metal square tubes and considering off-axis strength of each layer of composite. An expression is derived for mean crushing load and folding wave length in terms of mechanical properties and geometrical dimensions of metal tube and composite prepregs wrapped around it. To validate the theoretical model, predicted values for mean crushing load are compared with experimental and numerical results that show reasonably good agreement.
Rheology and Processing of Ni Based Nano-Composite Pastes for Electronic Assembly
Authors: Durairaja R. , Chiawea L. , Leong Kau Chee , Chu Wong Mee , Suan Liang Meng
Published: February 2011

Lead-free solder paste printing process accounts for majority of the assembly defects in the electronic manufacturing industry. In the stencil printing process, the solder paste must be able to withstand low and high shear rates, which results in continuous structural breakdown and build-up. The study investigates the effect of nickel additional to the thixotropic behaviour of lead-free Sn/Ag/Cu solder pastes using the structural kinetic model. A hysteresis loop test and constant shear test is utilized to investigate the thixotropic behaviour of the pastes using parallel plate rheometry in temperature 30 oC. In this study, the shear rates were increased from 0.01 s-1 to 10s-1 and the second curve was a result of decreasing shear rate from 10s-1 to 0.01s-1. For the constant shear test, the samples were subjected to two constant shear rates of 0.1s-1 and 1s-1. The constant shear rate test was designed to study the structural breakdown and build-up of the paste materials. From this investigation, hysteresis loop test was shown to be an effective test method to differentiate the extent of structural recovery in the solder pastes. The results of the structural parameter values obtained from the kinetic model showed a good correlation to the breakdown and build-up of the paste structure.
Flexural Performance of Strengthened RC Beams with CFRP Laminates Subjected to Cyclic Loading
Authors: Hawileh Rami , Abdallah Jamal A. , Al-Tamimi Adil K.
Published: February 2011

Seismic retrofitting of reinforced concrete (RC) beams by means of carbon fiber reinforced polymer (CFRP) composites is one of the state-of-the-art techniques that have been widely practiced lately. Such external strengthening schemes seem to enhance both stiffness and strength of RC beams when subjected to static and cyclic loading. Extensive research investigation has been carried out for beams subjected to monotonic static loading while limited research data is available for beams subjected to cyclic loadings. Therefore, this study is initiated and its aim is to present the results of full scale experimental testing of RC beams under four-point-bending loading and subjected to monotonic and cyclic loading histories up to failure of the specimens. An unstrengthened RC beam was tested monotonically to serve as a bench-mark. The remaining two externally strengthened RC beams with different anchorage schemes were tested under cyclic loading. The strengthening test matrix included beams bonded with a unidirectional CFRP plate that covers 90% of the beam's soffit length, with one or two unidirectional layers of CFRP wraps at anchorage locations along the beam's length. The anchorage locations were at the edges of the CFRP plate and at the middle of the beam's span. The results presented herein show an increase in the overall strength for the strengthened beams over the unstrengthened ones. The different failure modes and the resulting ductility of the tested specimens are also discussed. This study is considered to be the first part of an extensive program that aims to investigate the different parameters that govern the external strengthening techniques of RC beams when subjected to cyclic loading.
Large Deflection Behavior of Relatively Thick Functionally Graded Plates under Pressure Loads Using Higher Order Shear Deformation Theory
Authors: Sadr-Lahidjani Mohammad Homayoun , Hajikazemi Mohammad , Ramezani-Oliaee Mona
Published: February 2011

Large deflection analysis of thin and relatively thick rectangular functionally graded plates is studied in this paper. It is assumed that the mechanical properties of the plate, graded through the thickness, are described by a simple power law distribution in terms of the volume fractions of constituents. The plate is assumed to be under lateral pressure load. The fundamental equations for rectangular plates of FGM are obtained using the classical laminated plate theory (CLPT), first order shear deformation theory (FSDT) and higher order shear deformation theory (HSDT) for large deflection and the solution is obtained by minimization of the total potential energy.
Mechanical Vibration Technique for Enhancing Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite
Authors: Sayuti Mohd , Sulaiman Shamsuddin , Baharudin B.T. Hang Tuah , Arifin Mohd Khairol A. , Suraya S. , Esmaeilian Gholamreza
Published: February 2011

The effects of subjecting solidifying particulate reinforced aluminium alloy matrix composite to various sources of vibration on the resulting casting quality, a mechanical vibration technique for inducing vibration resulting in enhanced mechanical properties, such as impact properties is devised. TiC particulate reinforced LM6 alloy matrix composites are fabricated by different particulate weight fraction of titanium dioxide and microstructure studies were conducted to determine the impact strength and density, respectively. Preliminary works show that the mechanical properties have been improved by using vibration mold during solidification compared to gravity castings without vibration.
Effect of Quartz-Silicon Dioxide Particulate on Tensile Properties of Aluminium Alloy Cast Composites
Authors: Sayuti Mohd , Sulaiman Shamsuddin , Baharudin B.T. Hang Tuah , Arifin Mohd Khairol A. , Vijayaram T.R. , Suraya S.
Published: February 2011

This paper describes an experimental investigation of the tensile properties of quartz-silicon dioxide particulate reinforced LM6 aluminium alloy composite. In this experimental, quartz-silicon dioxide particulate reinforced LM6 composite were fabricated by carbon dioxide sand moulding process with variation of the particulate content on percentage of weight. Tensile tests were conducted to determine tensile strength and modulus of elasticity followed by fracture surface analysis using scanning electron microscope to characterize the morphological aspects of the test samples after tensile testing. The results show that the tensile strength of the composites decreased with increasing of quartz particulate content. In addition, this research article is well featured by the particulate-matrix bonding and interface studies which have been conducted to understand the processed composite materials mechanical behaviour. It was well supported by the fractographs taken using the scanning electron microscope (SEM). The composition of SiO2 particulate in composite was increased as shown in EDX Spectrum and Fractograph.
Immediate and Long-Term Deflection of Carbon Fiber Reinforced Polymer (CFRP) Concrete Beams
Authors: Ahmed Ehsan , Sobuz Habibur Rahman
Published: February 2011

This study presents the results of immediate and long-term deflections of reinforced concrete beams strengthened with carbon fiber reinforced polymer (CFRP) laminates under sustained loading The test parameters were sustained load and different degrees of strengthening scheme for both cracked and un-cracked sections of beams. The applied sustained load was 56% and 38% of the ultimate static capacities of the un-strengthened beams for cracked and un-cracked section respectively. The long term deflections of CFRP strengthened beams at six month were on average 1.42 times the immediate deflections for un-cracked beams and 1.45 times the immediate deflections for cracked beams. The experimental results indicate that the long-term deflection of cracked beam shows significantly higher value compared to that of un-cracked beams. A comparison of time dependent deformation between analytical and experimental results shows closer agreement for the un-cracked beam sections. More conservative theoretical estimation is observed in the case of cracked beam section in spite the inclusion of tension stiffening effect. Finally, factors affecting the long-term deflection of strengthened beams are discussed to get better understanding on the long term behaviour of strengthened beams.
Free Vibration Analysis of Symmetrically Laminated Fully Clamped Skew Plates Using Extended Kantorovich Method
Authors: Fallah Ali , Kargarnovin Mohammad Hossein , Aghdam Mohammad Mohammadi
Published: February 2011

In this paper, free vibration analysis of thin symmetrically laminated skew plates with fully clamped edges is investigated. The governing differential equation for skew plate which is a fourth order partial differential equation (PDE) is obtained by transforming the differential equation in Cartesian coordinates into skew coordinates. Based on the multi-term extended Kantorovich method (MTEKM) an efficient and accurate approximate closed-form solution is presented for the governing PDE. Application of the MTEKM reduces the governing PDE to a dual set of ordinary differential equations. These sets of equations are then solved with infinite power series solution, in an iterative manner until convergence was achieved. Results of this study show the fast rate of convergence of the MTEKM. Usually two or three iterations are enough to obtain reasonably accurate results. The frequency parameters of laminated composite plates are obtained for different skew angles and lay-up configuration for different composites laminates skew plates. Comparisons have been made with the available results in the literature which show the accuracy and efficiency of the method.
Thermal Buckling Analysis of Moderately Thick Plates Using Functionally Graded Strips
Authors: Nassirnia Mohammad , Ovesy Hamid Reza , Ghannadpour Seyyed Amir Mahdi
Published: February 2011

In the current study, the critical buckling of functionally graded plates (FGPs) subjected to thermal loads is evaluated using the finite strip method based on the first order shear deformation theory (FSDT). The material properties of these plates are assumed to vary in the thickness direction of the plate according to the power law distribution in terms of volume fractions of the constituents. The plates’ boundary conditions are assumed to be simply supported in all the edges or clamped in side edges and simply supported on the ends. The fundamental eigen-buckling equations for the plates are obtained by discretizing the plate into some strips, called functionally graded strip (FGS). The solution is obtained by the minimization of the total potential energy as well as solving the eigenvalue problem. The effects of material gradient index, aspect ratio and different thermal loadings (i.e. uniform temperature rise and nonlinear temperature change across the thickness) on the critical buckling temperature difference will be presented in some graphical forms.
The Effect of Bentonite Clay on Green Compression Strength for Tailing Sands from Old Tin Mines in Perak State, Malaysia for Making Green Sand Casting Mould
Authors: Abdullah A. , Sulaiman Shamsuddin , Baharudin B.T. Hang Tuah , Arifin Mohd Khairol A. , Vijayaram T.R.
Published: February 2011

Clay has an important role in making green sand casting mould beside water. Clay acts as binders, holding the sand grains together. Water is needed to activate the clay bond. Without the addition of water on clay, no strength would be achieved on sand mould, as the sand and clay would be just two dry materials. Bentonite clay was used in this study. Adequate clay content with suitable moisture in moulding sand is important for optimum strength and casting quality. Too little or too much clay will not give proper strength. Green compression strength is one of the mechanical properties to be considered for making green sand casting mould. The green compression strength of foundry sand is the maximum compressive strength that a mixture is capable of sustaining when prepared, rammed and tested according to standard procedure. For this study, test is conducted according to Foundry Sand Testing Equipment Operating Instructions from Ridsdale and Dietert. Result from this study indicates that tailing sand has potential for making green sand casting mould in term of green compression strength. Other factors that must be considered are permeability and shatter index.
Effect of Electron Beam Irradiation (EB) on Gas Barrier Property of HDPE/EPDM Nanocomposites
Authors: Jamal N.A. , Anuar Hazleen , Razak Shamsul Bahri A.
Published: February 2011

In this study, electron beam irradiated (EB) was applied as a crosslinker agent for both pristine high density polyethylene (HDPE) and HDPE/ ethylene propylene diene monomer (EPDM) nanocomposite systems. The doses rate for EB irradiated technique were varied between 50, 100, 150 and 200 kGy. The nanocomposites systems were first prepared via melt intercalation method with different organophilic montmorillonite (OMMT) loadings. It was found that, with 4 vol% organophilic montmorillonite (OMMT) loading, the barrier resistance of nanocomposite against oxygen transmission was significantly enhanced by EB irradiation dose rate of 100 kGy. The oxygen transmission for nanocomposite was reduced by 23.48%. The interplanar spacing, d-spacings of OMMT in nanocomposites were monitored using x-ray diffraction (XRD) and the extent of delamination was examined by transmission electron microscope (TEM). The wide angle of XRD patterns showed the increased interplanar spacing, d of clay layers, indicating enhanced compatibility between polymer matrix and OMMT with EB irradiation. TEM photomicrographs illustrated the mixed intercalated and partial exfoliated structures of the nanocomposites with the irradiation process.
Flexural Performance of RC Beams Strengthened with Different Reinforcement Ratios of CFRP Laminates
Authors: Sobuz Habibur Rahman , Ahmed Ehsan
Published: February 2011

In this paper, experimental study is carried out to evaluate the flexural performance of reinforced concrete beams strengthened with different ratios of carbon fibre reinforced polymer (CFRP) laminates. Four rectangular reinforced concrete beams strengthened with different reinforcement ratios of CFRP laminates are tested to failure under transverse bending on a simply supported span of 1.9 m. The increase of ultimate strength provided by the bonded carbon fiber is assessed and failure mode is identified. The results indicated that the flexural capacity of beam was significantly improved as the layers of laminates increased. It is concluded that the attachment of CFRP laminates has substantial influence on the performance of CFRP strengthened beams. However, de-bonding of CFRP laminates from the concrete surface is still a concern for the case of multi-layer strengthening of beam. Based on the observed results, recommendations are made to prevent the premature de-bonding failure of strengthened beams.
Investigation of Phase Transformation and Structure Evolution of Electrospun Copper Oxide Nanofibers during Thermal Annealing
Authors: Khadem Dariush Jafar , Yaakob Zahira , Shahgaldi Samaneh , Wan Daud Wan Ramli , Majlan Edy Herianto
Published: February 2011

One-dimensional nanostructures, like nanofibers, nanobelts, nanotubes, nanorods have been regarded as a new class of nanomaterials that have been attracted as the most promising building blocks for verity applications in the last few years. As one type of important structures with intensive research efforts have been devoted to the production and investigation of the metal oxides. Metal oxide nanofibers have different potential to play an essential role in a series of application such as optics, nanoelectronics, catalysts, sensors, storage, optoelectonics, and full cell. Copper oxide nanostructures is a promising semiconductor material with potential applications in photochemical, electrochemical, electrochromic especially in water splitting, catalysts, and fabrication of photovoltaic devices. In this paper electrospinning method via sol-gel was used to fabricate copper oxide nanofibers. Copper oxide nanofibers with different morphology were synthesized by different calcinations temperature. In this paper, effective parameters such as voltage, concentration of precursor and different calcinations temperature were characterized by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).
The Influence of Mercerised Kenaf Fibres Reinforced Polylactic Acid Composites on Dynamic Mechanical Analysis
Authors: Talib Rosnita A. , Tawakkal Intan Syafinaz Mohamed Amin , Khalina Abdan
Published: February 2011

The potential of using cellulose to reinforce the thermal stability of kenaf derived cellulose (KDC)/polylactic acid (PLA) composite was investigated in this study. The cellulose was derived from kenaf bast fibre which was chemically treated via chlorination and mercerisation processes. The composites with various loadings of cellulose (dry weight basis) ranging from 0% to 60% were produced by melt mixing and compression moulding. Dynamic mechanical properties namely storage modulus (E’), loss modulus (E”) and tan δ of the KDC/PLA composites and the commercial PLA were analysed and compared as a function of temperature. ESEM micrographs demonstrated that the mercerisation of kenaf fibres have successfully removed the lignin and hemicellulose, thus producing cellulose which can be observed by its rougher surface and greater size reduction than the raw fibre. The DMA results demonstrated that the storage modulus of 60% KDC/PLA composite is twice higher than the commercial PLA and the rest of the composites within a high temperature range (above 80°C). The glass transition temperatures (Tg) generated from the loss modulus curves exhibit that the peak of the loss modulus was shifted to higher temperature as the percentage of the cellulose loading was increased. These results show a better thermal stability of the composites when incorporated with the cellulose.
Influence of Processing Aids and Hydroxyapatite as Fillers on Flow Behaviour and Mechanical Properties of Ultra High Molecular Weight Polyethylene/High Density Polyethylene Composites
Authors: Ahmad Mazatusziha , Wahit Mat Uzir , Kadir Mohammed Rafiq Abdul , Dahlan Khairul Zaman Mohd
Published: February 2011

In this study, blends of ultra high molecular weight polyethylene/high density polyethylene/polyethylene glycol (UHMWPE/HDPE/PEG) and the composites containing Hydroxyapatite (HA) as reinforcement filler were prepared via single screw extruder nanomixer followed by compression moulding. PEG (2phr) was used as processing aid and HA loadings were varied from 10 to 50 phr. HDPE and PEG were introduced to improve the extrudability of UHMWPE. Rheological behavior was studied via capillary rheometer while flexural and izod impact tests were conducted in order to investigate the mechanical properties of the blends and composites. Melt viscosity of the blends was found to decrease with increasing shear rate indicating a pseudoplastic behaviour. Incorporation of PEG shows a synergism effect on the reduction of blends viscosity. Blend of 40% UHMWPE/ 60% HDPE/ 2 phr PEG was chosen as the optimum blend composition with a balance properties in terms of the mechanical properties and processability. The incorporation of HA fillers from 10 to 50 phr into the blend resulted in the increase of flexural modulus and flexural strength with a slight decline of impact strength values. It can be concluded that the composites having adequate strength and modulus within the range of cancellous bone properties were succesfully developed to be used as biomedical implant devices.
Feasibility of Manufacturing a Medium Density Fibreboard Made of 4-Year Old Rubber Tree RRIM 2020 Clone
Authors: Saffian Harmaen Ahmad , Harun Jalaluddin , Tahir Paridah Md , Khalina Abdan
Published: February 2011

This research was conducted to study the feasibility of producing medium density fibreboard (MDF) from 4-year old rubberwood clone RRIM 2020. The 4-year old rubberwood is obtained from different planting densities, which is 500, 1000, 1500 and 2000 trees/ha and were processed to produce MDF. The MDF is analyzed in term of its mechanical properties (static bending and densities to comply with JIS A 5905-2006 Standard (Type 30, MOR > 30.0 MPa and MOE > 2500 MPa and Type 25, MOR > 25.0 - 30.0 MPa and MOE > 2000 - 2500 MPa). MDF made from 25 year trees clone, PB260 which come from the same clone was used as a control. The results showed that the PB260 and the 4-year old rubberwood clone with planting densities of 500 trees/ha satisfied the requirement of Type 30, and the remaining passed at Type 25. It shows that it is feasible to produce an MDF using the 4-year old rubberwood clone.
Curing Characteristics and Mechanical Properties of Rattan Filled Natural Rubber Compounds
Authors: Muniandy Komethi , Hanafi Ismail , Othman Nadras
Published: February 2011

Rattan for its potential as a new type of filler was investigated in natural rubber (NR) compounds. Natural rubber (NR) compounds were prepared by the incorporation of rattan at different loadings into a natural rubber matrix with a laboratory size two roll mill. The effect of rattan loading as filler on curing characteristics, tensile properties, morphological properties using scanning electron microscopy (SEM) and rubber–filler interaction of rattan filled natural rubber compound were studied in the filler loading range of 0 to 30 phr. The results indicate that the scorch time (ts2) and cure time (t90) shorten with increasing filler loading, whereas the maximum torque (MH) showed an increasing trend. As the filler loading increases, the tensile strength and elongation at break decreases whilst tensile modulus; stress at 100 % elongation and stress at 300 % elongation increased. The rubber filler interactions of the rubber compound decreased with increasing filler loading. SEM studies indicate that the increasing rattan loading weakens the rubber-rattan interactions.
Evaluation of Physical and Mechanical Properties of Paulownia Wood Core and Fiberglass Surfaces Sandwich Panel
Authors: Sobhani Maryam , Khazaeian Abolghasem , Tabarsa Taghi , Shakeri Alireza
Published: February 2011

The purpose of this study was to determine some physical and mechanical properties of sandwich panels manufactured from the core of Paulownia wood and surfaces of multilayer of fiberglass and resins. Paulownia was selected among Hardwoods because of its s low density (0.26 g/cm3) and high strength/weight ratio. Eight treatments were used for experiments: Two kinds of fiberglass (needle and combination of the needle and curtain type), two various resins (polyester and epoxy) and two core thicknesses (9mm and 19mm). Physical properties including density, resistance to water absorption, Dimensional stability, and Mechanical Properties such as internal bonding, compressive and bending strength of panels were measured following ASTM Standard. The results indicated that panels with 19 mm thick core had lower density (0.5g/ cm3) compared to the 9mm thick panels (0.7g/cm3). Bigger volume of wood in the core of panels with higher thickness was the main reason of this result. The experimental results showed that thickness of wood was effective on the modulus of rupture, modulus of elasticity, and compressive strength, significantly. Epoxy resin presented higher internal bond compared to the polyester resin. The two kind of fiberglass (needle one and the combination of needle and curtain type) didn’t have noticeable differences on mechanical properties. It also was found that Paulownia is a promising species for manufacturing sandwich panel.
Investigation on the Microwave Properties of Kenaf and Rice-Husk Fiber Reinforced Pla Composite Utilizing One-Port Coaxial Transmission Line Reflection Method
Authors: Zawawi Nor'aini Ahmad , Ismail Alyani , Khalina Abdan , Mahdi Mohd Adzir
Published: February 2011

The paper investigates the microwave properties of natural fiber reinforced biodegradable plastic composites in order to recognize their potential as alternatives to common printed circuit board (PCB) for electronic communication industries. Thus, the paper reports on measured dielectric properties for two new composites under study: Kenaf/Poly Lactic Acid (PLA) and rice husk/PLA and their results are compared. The sample is made from equal weight percentage loading (50%wt - 50%wt) of kenaf and PLA. Another sample has also equal weight percentage loading (50% wt - 50%wt) of rice husk and PLA. The complex dielectric permittivity (ε = ε' – jε'') and loss tangent (tan δ) of the two samples of natural fibers plastic composites have been studied in the frequency range of 500 MHz to 10 GHz. The dielectric permittivity is measured by scattering parameter (S-parameter) using a Vector Network Analyzer (VNA). The concentration dependence of permittivity and loss tangent is analyzed for each sample. It is observed that from 500 MHz to 3.32 GHz, real permittivity (ε') values are consistent throughout the wide frequency range, at approximately 3.3. However, the permittivity seems to decrease at higher frequencies starting from 3.35 GHz for both samples, down to 2.5 at 10 GHz. Measured results show that kenaf/PLA mixture has higher permittivity (ε') than the rice husk/PLA composite across the wide frequency range. Meanwhile, loss tangent (tan δ) is low and remains similar for both types of fiber compositions.
Effects of Thickness on Fracture Toughness of Carbon/Polyester Composite
Authors: Heydari Mohammad Hossein , Choupani Naghdali
Published: February 2011

The aim of this paper is to evaluate interlaminar fracture toughness and non dimensional stress intensity factors of woven Carbon-Polyester composite based on numerical and experimental methods. A modified version of Arcan specimen was employed to conduct a mixed-mode fracture test using a special loading device. By changing the loading angle, α, from 0° to 90°, mode-I, mode-II and all mixed-mode data were created. The finite element analysis was performed with Abaqus software. The interaction j-integral was used to separate the mixed mode stress intensity factors and energy release rate at the crack tip under different loading conditions and different thickness of specimens. The results of fracture toughness tests revealed that the interlaminar fracture of composite is strong under the shearing-mode loading but weaker to the opening- mode loading. It can be seen that by increasing the thickness of the composite specimen, non dimensional stress intensity factors for pure mode I (α=0°) and pure mode II (α=90° ) loading conditions were decreased.
Impact Damage Detection in a Stiffened Composite Wing Panel Using Digital Shearography and Thermosonics
Authors: De Angelis Giovanni , Meo Michele , Almond D.P. , Pickering S.G. , Polimeno U.
Published: February 2011

There has been a growing interest in the use of composites especially in structural application ranging from aerospace to automotive and marine sectors. However, their performances under impact loading represent one of the major concerns as impacts may occur during manufacture, normal operations and maintenance. This paper presents two novel NDT techniques, thermosonics and digital shearography (DISH) to detect and assess barely visible impact damage (BVID) produced on a stiffened composite wing panel by unknown low energy impacts. Thermosonics is based on synchronized infrared imaging and ultrasonic excitation. Despite the apparent simplicity of the experimental setup, thermosonics involves a number of factors, e.g. acoustic horn location, horn crack proximity, horn-sample coupling etc., that significantly tend to influence both the degree and the period of the excitation. Then, a numerical-experimental procedure for the assessment of the size and depth of delamination by digital shearography (DISH) is proposed. The flaw detection capabilities of DISH have been evaluated by measuring the dynamic response of the delaminated area to applied stresses. The shearographic methodology is based on the recognition of the (0 1) resonance mode per defect. A simplified model of thin circular plate, idealized above each impacted area, is used to calculate the natural frequency of vibrating delamination. The numerical difference between experimental resonance frequencies and those computationally obtained is minimized using an unconstrained optimization algorithm in order to calculate the delamination depth. The results showed that thermosonics is a quick and effective method to detect and localize BVID damage while the combined shearography and optimization methodology was able to size and localize delamination due to low velocity impacts.
Optimum Condition of Manufacturing Wood-Based Composite from Mixture of Wood Particles/Walnut and Almond Shells
Authors: Pirayesh Hamidreza , Khazaeian Abolghasem , Khanjanzadeh Hossein , Bahrinejad Arian
Published: February 2011

The aim of this study was to manufacture wood based particleboard by using wood particles and agricultural residues of walnut and almond shells that have no economical value other than being used merely as low grade fuel and fodder and evaluating of its performance. This study was done at two stages; first determination of optimum press condition of producing boards from mixture of wood particles and walnut/almond shells and second stage was evaluation of the effect of different ratios of walnut/almond shells (10 and 30%) and the shell mesh size (≤ 0.7 and ≥ 2 mm) on their mechanical (modulus of rupture and modulus of elasticity and internal bonding) and physical (thickness swelling and water absorption) properties. The result of first stage of the study showed that of press pressure of 2.5 and 5 MPa, press temperature of 150 and 180 °C and press time of 5 and 10 minutes, optimum press condition of producing boards from mixture of wood particles and walnut/almond shells are press pressure of 2.5 MPa, press temperature of 180 °C and press time of 5 minutes. The result of second stage of the study showed no meaningful difference between mechanical and physical properties of composite boards containing 10 percent of walnut and almond shell with reference one (board A). Besides, the range of used almond and walnut mesh size had no meaningful differences.
Shell Mould Composite with Rice Husk
Authors: Harun Z. , Kamarudin N.H. , Badarulzaman Nur Azam , Wahab M.S.
Published: February 2011

For many years, precision investment casting foundries have periodically reported serious casting defects. One source is associated with the brittle ceramic shell mould which is very weak in tension and highly expose to the cracking mechanism. This situation not only lead to the appearance of defect in the end cast product but always attribute to the handling problem at the earlier stage in the investment casting industry. Due to this fact the strengthening mechanism of the brittle shell mold using reinforcement method was studied and investigated in this work. Rice husk was chosen as a reinforcement material as it contains silica element which can withstand high temperature of molten metal. Several testing procedures and characterization technique were carried out in order to measure the performance of the reinforced shell mould. Results show that the MOR value for the green reinforced shell mould is higher than the green body of non reinforced shell mould. Scanning electron microscope observations also show that the fiber alignment across the matrix structure increase the failure resistance and yet increase the strength of the shell mould green body. Furthermore, this reinforcement method using organic fiber leads to the pore enhancement and also leads to the new phase formation (zircon) in the fired reinforced body. Overall, this reinforcement method using rice husk increase the properties of the green and fired body of ceramic shell mould system.
Cotton Reinforced Biopolymer Matrix Composite: Effect of Ultraviolet (UV) on its Mechanical Properties
Authors: Zuraida Ahmad , Anuar Hazleen , Halim Zahurin , Abdul Majid Dayang Laila Abang , Fauziah M. Yusof
Published: February 2011

Research on the production of composites from natural fibers has an enormous attention from researchers due to environmental awareness, which focusing to produce compostable bio-based composites and renewable raw materials that can be safely disposed after their use without polluting the environment. This paper reports the study on the effect of the ultraviolet (UV) to the cotton/albumen composites (CAC). The CAC were prepared by using hands lay-up technique with 10 w/w % of cotton content and cured at room temperature for 14 days. The cured samples were cut before exposing to UV light up to 20 days. The increase in tensile strength was observed up-to 10 days of exposure before it is decreasing to about 15% after 20 days of exposure to UV. The morphological study through SEM micrograph shows that fibers breakage and the biopolymer matrix loss is more with longer duration of UV exposure.
Effects of Processing Temperature and Chemical Treatment on Tensile Strength of Kenaf Fiber - Reinforced Polypropylene Waste Composites
Authors: Judawisastra Hermawan , Falencia Fella , Abdullah Akbar H.D.
Published: February 2011

In this research, the influence of processing temperatures and fiber chemical treatments to mechanical properties of polypropylene (PP) waste – kenaf fiber composites was investigated. Results from experimental and theoretical calculation of composite tensile strength were compared. The composites were made of PP wastes and unidirectional kenaf fiber, and manufactured by hot press molding. The processing temperature variations were 175 oC, 185oC and 195 oC. The chemical treatment used were alkaline and permanganate treatment. Kenaf fiber – PP composites were successfully made with the void volume fraction less than 5%, maximum fiber volume fraction 48% and maximum longitudinal tensile strength 110 MPa or 238% higher than PP’s strength. For non- and alkali treated fiber composites, 185oC was the optimum processing temperature. Elevated processing temperature up to 195oC could decrease composite strength due to the degradation of fiber-matrix interface. The effect of permanganate treatment did not significantly affect the composites strength. However, the improvement of interfacial properties at elevated temperature was found by the use of permanganate treatment.