bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Strained Silicon by Electron Back Scattering Pattern Compared with Raman Measurement and Edge Force Model Calculation
Authors: Tomita Motohiro , Kosemura Daisuke , Takei Munehisa , Nagata Kohki , Akamatsu Hiroaki , Ogura Atsushi
Published: February 2011

Global and local strained-Si samples, namely strained-Si on insulator (SSOI) wafer and a Si substrate with a patterned SiN film were each evaluated by electron backscattering pattern (EBSP). In the EBSP measurements for SSOI, biaxial tensile stresses (biaxial tensile strains and compressive strain perpendicular to the surface) were obtained, whose values were consistent with those obtained by UV-Raman spectroscopy. One-dimensional stress distributions in the Si substrate with the patterned SiN film were obtained by EBSP, UV-Raman spectroscopy with a deconvolution method, and edge force model calculation. The results were well consistent with each other. EBSP allows us to measure stress and strain in the patterned SiN sample with 150-nm wide space. Furthermore, anisotropic biaxial stress including shear stress was also obtained by EBSP.
Energy Band Engineering of Metal Nanodots for High Performance Nonvolatile Memory Application
Authors: Pei Yan Li , Hiraki Tatsuro , Kojima Toshiya , Fukushima Takafumi , Koyanagi Mitsumasa , Tanaka Tetsu
Published: February 2011

In this work, high density and small size metal nanodots (MND) with different work-functions were fabricated as a floating gate of nonvolatile memory (NVM) devices by self-assembled nanodot deposition (SAND). The energy band engineering of NVM was demonstrated through controlling MND work-function. For single MND layer floating gate NVM, the retention time was improved by choosing high work-function MND. Furthermore, we proposed a new type NVM with a double stacked MND floating gate. Here, the high work-function MND are placed on the top layer and the low work-function MND are placed on the bottom layer. A large memory window and long retention time were obtained. However, the thermal electron excitation is dominant for the electron discharge process during retention. How to reduce the defects in MND layer is important for further improving of memory characteristics.
Structural Change during the Formation of Directly Bonded Silicon Substrates
Authors: Kato Tetsuji , Ueda Takaya , Ohara Yuji , Kikkawa Jun , Nakamura Yoshiaki , Sakai Akira , Nakatsuka Osamu , Zaima Shigeaki , Toyoda Eiji , Izunome Kouji , Imai Yasuhiko , Kimura Shigeru , Sakata Osamu
Published: February 2011

The use of Si(011)/Si(001) direct silicon bonding (DSB) substrates is a key element of future complementary metal-oxide-semiconductor device technology. In the conventional bonding process, it is necessary to remove interfacial SiO2 to achieve direct atomic bonding. In this study, using X-ray microdiffraction and transmission electron microscopy, we investigate the structural changes caused by oxide out-diffusion annealing (ODA). It is revealed that crystallinity of the bonded Si(011) layer is degraded after low temperature ODA and gradually recovered with an increase in the ODA temperature and annealing time, which is well correlated with the interfacial SiO2/Si morphology. Characteristic domain textures depending on the ODA temperature are also detected.
Si Nanodot Device Fabricated by Thermal Oxidation and their Applications
Authors: Takahashi Yasuo , Jo Ming Yu , Kaizawa Takuya , Kato Yuki , Arita Masashi , Fujiwara Akira , Ono Yukinori , Inokawa Hiroshi , Choi Jung Bum
Published: February 2011

Small single-electron devices (SEDs) consisting of many Si nanodots are fabricated on a silicon-on-insulator (SOI) wafer by means of pattern-dependent oxidation (PADOX) method. We investigated SEDs from two kinds of viewpoint. One is how to fabricate the nanodots, especially coupled nanodots, which are important to achieve quantum computers and single-electron transfer devices. The other is demonstration of new applications that tolerate the size fluctuation. In order to achieve multi-coupled nanodots, we developed an easy method by applying PADOX to a specially designed Si nanowire which has small constrictions at the ends of the wire. We confirmed the double-dot formation and position of the Si nanodots in the wire by analyzing the measured electrical characteristics. To achieve high functionality together with low-power consumption and tolerance to size fluctuation, we developed nanodot array device which has many input gates and outputs terminals. The fabricated three-input and two-output nanodot device actually provide high functionality such as a half adder and a full adder.
Capture/Emission Processes of Carriers in Heterointerface Traps Observed in the Transient Charge-Pumping Characteristics of SiGe/Si-Hetero-Channel pMOSFETs
Authors: Tsuchiya Toshiaki , Yoshida Keiichi , Sakuraba Masao , Murota Junichi
Published: February 2011

Transient phenomena related to carrier capture/emission processes in interface traps were observed in the the charge pumping (CP) characteristics of SiGe/Si hetero-channel pMOSFETs, i.e., the CP characteristics were found to depend on the on/off time of the gate pulse. From these observations, time constants for the processes both in SiGe/Si heterointerface traps and in gate-oxide interface traps were derived. The time constant is considered to depend on the energy level of the interface traps that are present over a wide range within the energy gap. Therefore, these phenomena provide an interesting way of evaluating the discrete energy levels of interface traps in nanometer-scale devices containing only a few traps.
Discrete Dopant Effects on Threshold Voltage Variation in Double-Gate and Gate-All-Around Metal-Oxide-Semiconductor Field-Effect-Transistors
Authors: Mori Nobuya , Kamakura Yoshinari , Mil'nikov Genaddy , Minari Hideki
Published: February 2011

Quantum-transport simulations of current-voltage characteristics are performed in ultra-small double-gate and gate-all-around metal-oxide-semiconductor field-effect-transistors (MOSFETs) with a single attractive ion in the channel region. The ion induces a threshold voltage shift, whose origin is attributed to an ion-induced barrier lowering (IIBL). An analytical expression for the IIBL in ultra-small MOSFETs is derived. The analytical expression for the IIBL consists of two terms: a term related to the potential curvature at the potential top and a correction term due to the screening effects. The analytical model reproduces reasonably well the stimulated IIBL in the subthreshold region.
Interconnect Design Challenges in Nano CMOS Circuit
Authors: Masu Kazuya , Amakawa Shuhei , Ito Hiroyuki , Ishihara Noboru
Published: February 2011

In the conventional scaling scheme, interconnect delay cannot be reduced and the global interconnect delay become worse if the length of the wire is not scaled. The conventional approaches of global interconnect design are (1)introduction of inverse scaling concept where the upper metal layers have larger cross sections than lower metal layers, (2)insertion of repeaters, and (3) architecture level approach of multi/many core. In order to improve global interconnect delay even in aggressively miniaturized circuit, we have developed the transmission lien interconnect. This paper describes the novel analytical interconnect length distribution and discussion on future interconnect design direction. Then, recent our developments of the transmission line interconnect are described and performance comparison with another global wiring scheme such as optical interconnection is discussed.
Electronic Structure and Spin-Injection of Co-Based Heusler Alloy/ Semiconductor Junctions
Authors: Itoh Hiroyoshi , Honda Syuta , Inoue Junichiro
Published: February 2011

The electronic structures of Co-based Heusler alloys with nonstoichiometric atomic compositions as well as those at the interface of semiconductor junctions are investigated using first principles band calculations. It is shown that the electronic structure of a Co-based Heusler alloy is half-metallic, even for nonstoichiometric but Co-rich compositions, whereas the half-metallicity is lost for Co-poor compositions. It is also shown that magnetic moments at the interface of Co2MnSi/ Si junctions are sensitive to the growth direction and interface structure of the junctions. Efficient spin-injection into Si can be achieved by using a (111)-oriented Co-rich Heusler alloy and controlling the layer-by-layer stacking sequence at the interface.
Nanosize Electronics Material Analysis by Local Quantities Based on the Rigged QED Theory
Authors: Senami Masato , Ikeda Yuji , Hara Takaaki , Tachibana Akitomo
Published: February 2011

In this article, we propose two analysis method using novel local quantities. One method is related to the dynamics of electron spin. This is described by novel quantities, the spin torque and the zeta force. These quantities govern the dynamics of the spin of electrons, and hence can clarify the essential description of the dynamics of electron spin. The other method is related to the conductivity of nanosize materials. For this method, we introduce external and internal local conductivities. A microscopic viewpoint is important for the analysis of nanosize material. As a first step, we show the validity and usefulness of our methods. The zeta force clarifies how the local torque works on the electron spin in molecules. The external and internal local conductivities show how electrons pass through nanosize materials and how electrons are locally accelerated in the materials.
Atomically Controlled Plasma Processing for Group IV Quantum Heterostructure Formation
Authors: Sakuraba Masao , Sugawara Katsutoshi , Murota Junichi
Published: February 2011

By low-temperature epitaxial growth of group IV semiconductors utilizing electron-cyclotron-resonance (ECR) plasma enhanced chemical vapor deposition (CVD), atomically controlled plasma processing has been developed in order to achieve atomic-layer doping and heterostructure formation with nanometer-order thickness control as well as smooth and abrupt interfaces. In this paper, typical recent progress in plasma processing is reviewed as follows: (1) By N and B atomic-layer formation and subsequent Si epitaxial growth on Si(100) without substrate heating, heavy atomic-layer doping was demonstrated. Most of the incorporated N or B atoms can be confined in about a 2-nm-thick region of the atomic-layer doped Si film. (2) Using an 84 % relaxed Ge buffer layer formed on Si(100) by ECR plasma enhanced CVD, formation of a B-doped highly strained Si film with nanometer-order thickness was achieved and hole mobility enhancement as high as about 3 was observed in the highly strained Si film.
Effects of Direct Current and Pulse Electrodeposition Parameters on the Properties of Nano Cobalt Coatings
Authors: Allahkaram Saeed Reza , Towhid N. , Cheraghi M. Siadat
Published: February 2011

The aim of this study was to investigate the effects of direct current (DC) and pulse current (PC) parameters on the properties of cobalt (Co) coatings electrodeposited from a chloride acidic bath. The effects of peak current density, frequency and duty cycle on the surface morphology, crystal size, thickness, current efficiency, and preferred orientation of the deposits were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental thickness of the deposit was lower for pulse plating compared to that of DC plating. The current efficiency was comparatively higher for pulse plating. Less porosity and fine grains were formed by pulse plating. From XRD analysis, the calculated grain sizes of nano and micro Co coatings were around 65nm and 430nm, respectively. The results showed that, with an increase in duty cycle, grain sizes would increase, too. As pulse frequency was increased to 50Hz, grain sizes would also decrease. However, at higher frequencies, grain sizes would increase again.
An Investigation on Relative Post-Buckling Stiffness Variations of Symmetrically Cross-Ply Laminates
Authors: Ghannadpour Seyyed Amir Mahdi , Ovesy Hamid Reza , Hajikazemi Mohammad
Published: February 2011

In this paper, the theoretical developments of an exact finite strip for the buckling and initial post-buckling analyses of symmetrically cross-ply laminates are presented. The so-called exact finite strip is developed based on the concept that it is effectively a plate. In the development process, the Von-Karman’s equilibrium equation is solved exactly to obtain the buckling loads and the corresponding form of out-of-plane buckling deflection modes. The investigation of thin flat plate buckling behavior is then extended to an initial post-buckling study with the assumption that the deflected form immediately after the buckling is the same as that obtained for the buckling. The post-buckling study is effectively a single-term analysis, which is attempted by utilizing the so-called semi-energy method. In this method, the Von-Karman’s compatibility equation governing the behavior of symmetrically laminated composite plates is used together with a consideration of the total strain energy of the plate. Through the solution of the compatibility equation, the in-plane displacement functions are developed in terms of the unknown coefficient in the assumed out-of-plane deflection function. These in-plane and out-of-plane deflected functions are then substituted in the total strain energy expressions and the theorem of minimum total potential energy is applied to solve for the unknown coefficient. The developed method is subsequently applied to investigate the relative post-buckling stiffness variations of some representative thin symmetric cross-ply laminates for which the results are also obtained through the application of a semi-analytical finite strip method.
Tensile Properties and Micromorphologies of Sawdust and Chipwood Filled Epoxy Composites
Authors: Hisham S. , Faieza A.A. , Ismail N. , Sapuan S.M. , Ibrahim M.S.
Published: February 2011

In this study, waste wood product obtained from the timber industry originating from various type of wood has been investigated. Research work carried out on the three different sizes of fiber derived from the sawdust (SW) and chip wood (CW). The SW and CW fiber and epoxy resin were blended together respectively using hand tools machine, all specimens of fiber composite were prepared accordance to the ASTM standards. Tensile and morphological properties provide an excellent measure of the degree of reinforcement provided by the fiber to the composite. The tensile modulus increased with the filler size from coast to rough of composites both SW and CW but decreases steadily with the wood–fiber size from rough to soft content. Statistical analysis using one way and two ways analysis of variances (ANOVA) showed that the differences of results obtained from those SW and CW fiber composite samples are significant, which confirm a very firm mechanical performance of the composites through tensile tests. This shows the producing a good quality of SW and CW fibres composite which maybe used for home furniture utilities.
Manufacturing High Performance Wood Composite Panel from Paulownia
Authors: Rafighi Ali , Tabarsa Taghi
Published: February 2011

Regarding conservation policies of natural forests and environmental concerns forced wood composite panel manufacturers to consider using other lingo-cellulosic resources. Plantation fast growing species such as poplar, eucalyptus , paulownia and others is already started in many countries. Fast growing trees usually produce light wood with low strength so manufacturer has low certainty on using them for manufacturing wood composite panel. This study oriented toward examination of application of paulownia wood particle for manufacturing wood composite panel. In this study, specific press pressure at two levels (30 bar and 40 bar) , and press time at two levels (8 and 12 minutes) were used as independent variables. 12 experimental panels were made in laboratory. Mechanical properties such as MOR, MOE and IB were evaluated. Results showed that panels made at press pressure of 40 bar and press time of 12 minutes presented the highest MOR (41.28 MPa) and MOE (4128 MPa) but the highest IB (1.14 MPa) was observed in composite panels made at press pressure of 30 bar and press time of 8 minutes. Based on EN Standard MOR of Particleboard ranged from 12 to 15 MPa and MOE ranged from 2500 to 3000 MPa and IB ranged from 0.4 to 0.6 MPa . Comparing Above mentioned values with EN values it can be seen that Mechanical properties of wood composite panels made from paulownia are much higher than EN standard. These results are very good ground to focus on fast growing species such as paulownia to compensate wood raw material shortcoming in wood industry.
Kenaf Nanofiber/Polylactic Acid (PLA) Nanocomposite
Authors: Lasat Agnes Surai , Khalina Abdan , Ibrahim Nor Azowa
Published: February 2011

Kenaf fiber was treated with alkaline to reduce lignin content and tested under Fourier transform infrared spectroscopy (FTIR). FTIR result showed that peak at 1146 cm-1 which is acetyl group of lignin was reduced in treated fiber while disappearing of carbonyl group in treated kenaf fiber at 1750cm-1 was significantly shown compared to untreated kenaf fiber. Treated fiber undergoes mechanical size decrement process by high pressure homogenizer with 500bar pressure and 60 passes. Transmission Electron microscopy (TEM) was used to determine size and distribution of fiber. Moreover, morphology of nanofiber was observed under scanning electron microscope (SEM). Nanofiber (3%, 5%, 8% and 10%) was mixed with PLA using internal mixer and then compressed with hot pressed to produce specimen for tensile test. Tensile strength and tensile modulus of nanocomposite with 10% of nanofiber increased by 30% and 85% respectively compared to pure PLA.
Tensile and Thermal Conductivity Properties of Epoxy Nanocomposites Thin Film by Spin Coating Technique
Authors: Voo T.V. , Mariatti M. , Sim L.C.
Published: February 2011

This work aims to enhance thermal conductivity of thin film without compromising the other properties of polymer. In this study, three types of fillers in nano size with high thermal conductivity properties were studied; silicon nitride, boron nitride and synthetic diamond. The contents of fillers were varied between 0-2 vol. %. Epoxy nano-composite solution filled with high thermal conductivity fillers was spun at 1500-2000 rpm to produce thin film in the thickness of 40-60 µm. Thermal conductivity properties were measured by using hot disc technique. It was found that the thermal conductivity increases as filler loading increases. The mechanical properties of the thin film epoxy composites were determined by using tensile test (ASTM D882). As predicted, the tensile modulus was found increasing with the addition of fillers and reasonable agreements were obtained from the SEM images of the fracture surfaces.
Effect of Filler Loading and Coupling Agent on Tensile and Impact Properties of Polypropylene with Oil Palm Ash Composites
Authors: Ibrahim M.S. , Faieza A.A. , Sapuan S.M. , Tahir S.M.
Published: February 2011

The purpose of this research is to investigate the effect of filler loading and using coupling agent on tensile and impact properties of thermoplastic polypropylene composite with oil palm ash (OPA) powder. This research is intended to discover the dependant various effect of loading percentage weight of filler OPA and coupling agent maleated anhydrate polypropilene (MAPP) on tensile and impact properties of thermoplastic composite. This materials is weighed as OPA loading percentage 0%, 1%, 3%, 5% and 7% while the loading percentage of coupling agent MAPP 0%, 3%, 6%, 10% and 12% affect the mechanical properties of thermoplastic composite. Mixture process has been carried out using double-screwed extruder machine at constant speed and temperature,while board manufacturing of PP/OPA composite are made used hot press and cold press machine. Loading OPA and MAPP effect on polypropylene composite were tested through mechanical testing , specifically for tensile and impact properties. All testing methods are predicated from ASTM's standard (American Society for Testing and Material). Results showed lower OPA content and highest MAPP in ratio giving the highest tensile and impact strength of the composite.
Multisphere Ceramic Composite Concept and its Numerical Study of the Ballistic Response
Authors: Stanislawek Sebastian , Morka Andrzej , Niezgoda Tadeusz
Published: February 2011

Numerical investigations were performed to determine the influence of the spherical convex shape ceramic - alumina composite in reference to the standard double layer panel. All versions of the target were verified in an impact test including influence upon the position of the AP (Armor Piercing) 7,62x51HHS impact. The crucial parameter which was used for this verification was change in time of the PROJECTILE kinetic energy. The problem has been solved with the usage of the modeling and simulation methods as well as finite elements method implemented in LS-DYNA software. Space discretization for each option was built by three dimension elements guarantying satisfying accuracy of the calculations. For material behavior simulation specific models including the influence of the strain rate and temperature changes were considered. Projectile’s core made of HHS and aluminum plate material were described by Johnson-Cook model and ceramic target with Johnson-Holmquist model. In the studied panels the area surrounding back edges was supported by rigid wall. The obtained results show interesting properties of the new structures considering their ballistic resistance. However only certain places were chosen for tests, the protection ability against projectile attack is in general higher than the reference model. What is particularly interesting during the 6.6mm from the sphere center impact the sphere surface trajectory deviation effect is present. A projectile is not stopped here by material strength but the front layer shape. Moreover it can be assumed that this phenomenon will take place on majority of points on the sphere surface. Despite this fact, a ceramic multi sphere layer is less susceptible to overall destruction, depending on the impact point. The results of those numerical simulations can be used for designing of modern armor protection systems against hard kinetic projectiles.
Effects of Impregnation Time on Physical and Tensile Properties of Impregnated Sugar Palm (Arenga pinnata) Fibres
Authors: Ishak M.R. , Leman Zulkiflle , Sapuan S.M. , Rahman M.Z.A. , Anwar U.M.K.
Published: February 2011

The aim of this study is to investigate the effect of impregnation time on physical and tensile properties of sugar palm (Arenga pinnata) fibres. The fibre was impregnated with phenol formaldehyde (PF) and unsaturated polyester (UP) with various impregnation times (0, 5, 10, 15, 20, 25 min) at constant impregnation pressure of 1000 mmHg, before it was released within 30 s. Significant improvement in physical properties was observed after being impregnated for 5 min especially for fibre impregnated with PF due to its low moisture content (MC) and water absorption (WA). However, no significant changes in specific gravity for both impregnated fibres were observed. Fibre impregnated with UP for 5 min shows notable improvement in tensile strength and better fibre toughness while the fibre impregnated with PF showed lower tensile strength and elongation at break and higher tensile modulus than un-impregnated fibre. Since the PF-impregnated fibre become brittle and results in lower fibre toughness as shown in the stress strain behavior, this causes for poor fibre properties. However, there was no significant difference (p≤0.05) between all impregnated fibres in physical and tensile properties after impregnation time was extended from 10 to 25 min. In general, by increasing time of impregnation did not give much effect in improving physical and tensile properties of fibres.
Effects of Impregnation Pressure on Physical and Tensile Properties of Impregnated Sugar Palm (Arenga pinnata) Fibres
Authors: Ishak M.R. , Leman Zulkiflle , Sapuan S.M. , Rahman M.Z.A. , Anwar U.M.K.
Published: February 2011

The aim of this study is to investigate the effect of impregnation pressure on physical and tensile properties of sugar palm (Arenga pinnata) fibres. The fibre was impregnated with phenol formaldehyde (PF) and unsaturated polyester (UP) with different impregnation pressures (1000, 900, 800, 700, 600 and 500 mmHg) at constant impregnation time of 5 min. Significant improvement in physical properties was observed due to reduction of moisture content (MC) and water absorption (WA) after being impregnated from 1000 to 500 mmHg while PF-impregnated fibre was showing more superior. Improvement in mechanical properties was also observed after being impregnated where much better tensile properties and toughness were found at UP-impregnated fibres while PF-impregnated fibres were found to be very much lower in toughness. This study concluded that in order to obtain a high toughness and better physical properties of sugar palm fibre, the fibre should be impregnated with UP resin with impregnation pressure of 600 mmHg.
Indentation Analysis of In-Plane Prestressed Composite Sandwich Plates: An Improved Contact Law
Authors: Hosseini Mehdi , Khalili Seyyed Mohammad Reza , Fard Keramat Malekzadeh
Published: February 2011

In this article a closed form solution is derived for the deformation response of a composite sandwich plate subjected to static indentation of a flat-ended cylindrical indenter. The facesheet deflection is several times the laminate thickness so that bending moments may be neglected and only membrane forces are considered in the facesheet. In contrast to the existing analytical model for the indentation of composite sandwich plates, in the present model, the stacking sequence of the facesheets can be completely arbitrary, so that the shear-extension coupling terms, i.e. and , can also be included in the analysis. Furthermore, in the present model the effects of the initial in-plane normal and shear stresses on the edges of the sandwich plate are also considered. An improved contact law is derived based on the minimum total potential energy principle. The elastic strain energy, the plastic work dissipated in crushing the core and the external work are calculated using an appropriate shape function for the facesheet deflection. The relations between the indentation load and the deflection and length of deformation are obtained by minimization of the total potential energy. Analytical predictions of the load-indentation response compare well with experimental results. The effects of stacking sequence, ply thickness, number of layers and initial in-plane forces on the load-indentation response are studied and discussed.
Vibration Analysis of Thick Arbitrarily Laminated Plates of Various Shapes and Edge Conditions
Authors: Pervez Tasneem , Al-Jahwari F.K.S. , Seibi Abdennour
Published: February 2011

Free vibration analysis of arbitrarily laminated plates of quad, penta and hexagonal shapes, which have combinations of clamped, simply supported and free edge conditions is performed. The finite element formulation is based on first and higher order shear deformation theories to study the free vibration response of thick laminated composite plates. A finite element code is developed incorporating shear deformation theories using an 8-noded serendipity element. The effect of plate shape, arbitrary lamination and different edge conditions on natural frequencies and mode shapes are investigated. A systematic study is carried out to determine the influence of material orthotropy and aspect ratio on free vibration response. For various cases, the comparisons of results from present study showed good agreement with those published in the literature.
Notch Effect on Discontinuous Fiber Reinforced Thermoplastic Composites
Authors: Haldar Amit Kumar , Senthilvelan S.
Published: February 2011

Increasing utilization of thermoplastic composites in the structural application necessitates understanding of damage tolerance characteristics. In this work, unreinforced, 20 % short, 20 % long glass fiber reinforced polypropylene were injection molded and considered. Test specimens with different notch sizes were tested under static as well as fatigue loading conditions. Under static load condition, short fiber reinforced and unreinforced test material exhibited notch strengthening effect; whereas long fiber reinforced material exhibited notch weakening effect. Failure morphology under fatigue condition exhibited the influence of notch size and length of reinforced fibers over performance. Significant difference between notched and unnotched specimens is observed at low cycle fatigue and very less difference in performance is observed at high cycle fatigue condition.
Analysis of Energy Absorption on Pultruded Composite Tube under Oblique Loading
Authors: Sulong Abu Bakar , Ariffin Abdullah Atiq , Sahari Jaafar , Suherman Hendra
Published: February 2011

The capability of structures to absorb as much amount energy, particularly in automotive structures to reduce the damages due to impact energy during collision attract attention of many reserachers. During the actual collision, the crash box is not only experienced axially crash, but also in oblique crash. In this study, an experiment was carried out to study the crashworthiness parameters and behaviour of pultruded fibre E-glass/polyester pultruded composite tubes under oblique loading. Quasi-static loadings were applied axially and oblique on the pultruded composite to investigate the response of force-displacement during progressive collapses. The pultruded wall thickness of 6 mm tubes were used and four oblique angles of 0˚, 5˚, 10˚ and 15˚ were selected to study their effect on crushing behaviours and collapse modes using compression moulding. All specimens were chamfer 45˚ on top end for purpose to work as a collapse trigger mechanism. The results showed that the energy absorption of the structures increasing with decrease of the loading angle.
Fatigue Life Prediction of Composite Materials: Artificial Neural Networks vs. Polynomial Classifiers
Authors: El Kadi Hany A.
Published: February 2011

Artificial neural networks (ANN) and polynomial classifiers (PC) have been successfully used to predict the fatigue failure of fiber reinforced composite materials. This includes predicting the behavior of the same material subjected to different loading conditions as well as predicting the fatigue behavior of different materials. In this work, the fatigue life prediction obtained using both methods will be compared. The effect of the various parameters influencing the prediction will be presented and the advantages and disadvantages of each of the methods will be discussed.
Nanotechnology in Pulp and Paper Industries: A Review
Authors: Mohieldin S.D. , Zainudin E.S. , Paridah M.T. , Ainun Z.M.
Published: February 2011

Cellulose and lignocellulose have great potential as nanomaterials because they are abundant, renewable, have a nanofibrillar structure, can be made multi¬functional and self-assemble into well-defined architectures. New methods for liberating these materials, including nanodimensional cellulose fibrils, macromolecules and nanominerals will be needed in order to use the techniques developed for other nanomaterials as platforms for creating new wood-based materials and products. Research findings showed promising results in application of nanotechnology at different aspects of papermaking. Electrospinning; chemical treatment followed by mechanical techniques; or mechanical isolation methods were applied by different research groups to prepare cellulose nanofibres.
Effect of Carbon Black and Fly Ash Fillers on Tensile Properties of Composites
Authors: Raja R. Satheesh , Manisekar K. , Manikandan V.
Published: February 2011

Fibre reinforced polymer composites play an incredible role in almost all spheres of day to day life and the field of carbon composites is one of the prime research area in recent decade. Polymers are mostly reinforced with fibre or fillers to obtain better mechanical properties. The properties of the polymer composites can be improved largely by varying the type of filler/fibre materials and its volume percentage. Composites properties depend on the size, shape and other physical properties of the reinforcements. A relative easy way to improve the mechanical properties of a polymer is the addition of filler materials. In all particulate filled systems, the adhesion between the matrix and filler plays a significant role in determining the key properties such as strength and toughness. The mechanical properties of composites are also influenced by the filler’s nature, size and distribution profile, aspect ratio, volume fraction, the intrinsic adhesion between the surfaces of filler and polymer. In this paper, the effect of filler material on mechanical properties of E-Glass fibre reinforced polymer has been studied out by varying filler materials. For these study three different types of specimens were prepared, viz FRP without filler material, the FRP with 10 volume percentages of carbon black and the FRP with 10 volume percentage of Fly ash as filler material. The polyester composites were fabricated by hand-layup method. Mechanical properties of the specimens are analyzed using computerized Universal Testing Machine as per ASTM D 638 standards. The resulting behavioral patterns of the FRP with filler material are listed and compared to those of the FRP without filler material. Mechanical properties such as ultimate tensile strength, percentage of elongation, yield strength, Poisson’s ratio and percentage reduction in area were found out.
Influence of Surface Modifications on Interfacial Interaction of Zeolite Filled Polymer Composites
Authors: Zaharri N. , Othman Nadras , Mohd Ishak Z.A.
Published: February 2011

Interfacial interaction in zeolite filled polymer composites was investigated in this study. Two types of polymer which are polypropylene (PP) and ethylene vinyl acetate (EVA) were used as matrix in the preparation of the composites. Moreover, different modifications of zeolite filled polymer composites such as zeolite surface treatment with vinyl silane and alkylammonium and also chemical crosslinking were done to improve the interfacial adhesion between zeolite and polymer matrix. The zeolite filled polymer composites were homogenized using Thermo Haake Polydrive internal mixer and then compression molded into sheets according to standard test specimen. Uniaxial tensile test was performed in order to evaluate the mechanical behavior of the composites. The obtained experimental data for ultimate stress was correlated with Pukanszky theoretical model. The experimental results for all systems of zeolite filled polymer composites showed a good fit to the Pukanszky model. Interfacial interaction for each system of zeolite filled polymer composites was theoretically evaluated by determining the parameter B through this model. The value of parameter B for all zeolite filled polymer composite systems differs significantly from one another thus suggesting the applicability of this Pukanszky model in characterizing the filler-matrix interfacial adhesion.
Optimal Design by Elitist-Genetic Algorithm for Maximum Fundamental Frequency of Fiber Metal Laminated Plates
Authors: Bargh Hadi Ghashochi , Sadr-Lahidjani Mohammad Homayoun
Published: February 2011

In this paper, fundamental frequency optimization of fiber metal laminated plates is studied using the combination of Elitist-Genetic algorithm (E-GA) and finite strip method (FSM). The design variables are the number of layers, the fiber orientation angles of inner composite layers, edge conditions and plate length/width ratios. The classical laminated plate theory (CLPT) is used to calculate the natural frequencies and the fitness function is computed with a semi-analytical finite strip method which has been developed on the basis of full energy methods. To check the validity, the obtained results are also compared with some other stacking sequences.
The Study of Biodegradable Thermoplastics Sago Starch
Authors: Zuraida Ahmad , Anuar Hazleen , Yusof Yusliza
Published: February 2011

The motivation of this work is to lessen the dependence on non-degradable plastic packaging which can lead to waste disposal problems. In this paper, the alternative biodegradable material developed by using local available sago starch in the present of biodegradable glycerol as plasticizer, as well as a set of composition added with citric acid as co-plasticizer is reported. Starch was added with 15-30 w/w% of glycerol to prepare workable bioplastics. The samples were characterized by Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and tested for mechanical properties. The results reveale that, the tensile strength of the bioplastic is increasing with the increasing of glycerol until the optimum amount of 30 w/w%. The similar trend is also observed upon the addition of the citric acid. The decrease of the strength after the optimum point, however is obvious in the specimens with the addition of citric acid which is about 50% lower than the specimen without citric acid.
Cotton Reinforced Biopolymer Matrix Composite: Effect of Curing and Aging Conditions on its Mechanical Properties
Authors: Zuraida Ahmad , Yusof Yusliza , Halim Zahurin , Fauziah M. Yusof
Published: February 2011

The attention in natural fiber reinforced biopolymer composite materials has been rapidly growing both in terms of industrial applications and basic research. This study investigated on the effect of aging time on mechanical properties and morphological structure of thermoset protein-based composites from egg albumen reinforced by natural cotton fibres. The cotton/albumen composites (CAC) were fabricated by hands lay-up technique with 10 w/w % of fiber content. The samples were cured and aged at room temperature for different aging time from 7 to 32 days. The cotton fibres have contributed in a significant improvement in mechanical strength and toughness of the composites. Tensile strength of the composites achieved the optimum strength of 9 MPa after 21 days of aging time and constant till 32 days. As the aging time increased, impact strength of the composites also improved to some value of 20 kJ/m2. Thereby after 21 days observation, the composites show an equilibrium moisture content of 6-9 wt%, and the strength remains stable at room condition with 50-60% relative humidity (RH). Morphology studied using SEM justify that the moisture content after aging time influenced mechanical properties of the composites.
Influence of Polyacrilonitrile (PAN) Concentration on the Mechanical and Physical Properties of Electrospun Fibres
Authors: Karim Siti Saniah Ab. , Sulong Abu Bakar , Azhari Che Husna , Hwei Ng Min , Yusof Mohd Reusmaazran
Published: February 2011

Electrospinning is direct process to produce polymer fibre with high specific surface area ratio. Apart from polymer fibre producing; electrospinning also can produce a continuous nano size of polymer fibre, which the benefit of this process is the fibre can be produced straight away with lower cost than conventional melt spinning process. Recently, successful attempts have been made to produce polymer fibre by adjusting the parameters of electrospinning such as the collector distance, needle size, polymer concentration voltage applied. From this study, the electrospun fibre was distributed randomly on collector plate surface. The diameter of the fibre produced increase as the polymer concentration was increased. The fibre distribution does not affected by the differ polymer concentrations electrospun, but there were polymer beads formed at the low polymer concentration in solvents. The fiber elongation value is the highest by polymer fiber of 9 wt % while the highest strength is by polymer fiber of 7 wt %. The polymer fibre with low concentration consequently showed the brittle characteristic.
The Behavior of Construction Waste Concrete
Authors: Doh Shu Ing , Koid C.H. , Ng G.Y. , Teo S.H. , Adilen Suil
Published: February 2011

Due to urbanisation and rapid development in Malaysia, the waste generated from the construction has increased tremendously. Such waste accumulation has been a major issue not only in Malaysia but also worldwide. In line with this, recycling construction as coarse aggregate can be introduced to solve two environmental aspects namely waste disposal crisis while protecting from depleted natural resources. In this study, three types of construction waste namely floor tiles, clay bricks and crushed concrete aggregate were used to replace coarse aggregate in concrete production. The effect of coarse aggregate replacement on the workability, compressive strength, and flexural strength Grade 30 concrete were investigated and discussed. The concrete specimens that made of crushed floor tiles, crushed bricks, and crushed concrete aggregate were termed as tile concrete (TC), brick concrete (BC) and crushed aggregate concrete (CAC). The result for all specimens has shown good workability with slump ranging from 51-85 mm. BC showed optimum brick replacement of 17% with the 28-day compressive strength of 36 N/mm2. TC and CAC on the other hand showed optimum result at 20% and 16% replacement with 28-day compressive strength of 31.43 N/mm2 and 31.25 N/mm2 respectively. It can be concluded that optimum result for BC, TC and CAC have achieve concrete G30. The flexural strength of BC, TC and CAC ranges from 3.03-4.49 N/mm2, 3.62-4.60 N/mm2, and 4.05-5.43 N/mm2.
Effect of Core Thicknesses on Impact Performance of Thermoplastic Honeycomb Core Sandwich Structure under Low-Velocity Impact Loading
Authors: Sawal Nurashikin , Hazizan Md Akil
Published: February 2011

Low-velocity impact test on sandwich panels composed of aluminum face sheets and thermoplastic honeycomb cores have been performed to characterize the impact performance as a function of core thickness and drop heights. Impact parameters like maximum impact force, impact energy and impact damage area were evaluated and compared. Consequent damages were inspected visually on the impact surface as well as the rear surface. The experimental results found that panels with thicker core exhibited higher impact force than thinner core counterparts, allowing the panel to absorbed more energy. Higher degree of impact damage can be observed at elevated drop heights as most of the damage took the form of local core crushing, face sheet buckling and debonding between the face sheet and core,. Resulting damage area were different according to the core thickness as thicker core prone to absorbed more energy that lead to more damage propagation.
Parametric Study of Automotive Composite Bumper Beams Subjected to Frontal Impacts
Authors: Nursherida J. Mai , Barkawi Sahari B. , Nuraini A.A.
Published: February 2011

The parametric study of automotive composite bumper beam subjected to frontal impact is presented and discussed in this paper. The aim of this study is to analyze the effect of steel and composite material on energy absorption of automotive front bumper beam. The front bumper beams made of e-glass/epoxy composite and carbon epoxy composite are studied and characterized by impact modeling using LS-DYNA V971, according to United States New Car Assessment Program (US-NCAP) frontal impact velocity and based on European Enhanced Vehicle-safety Committee. The most important variable of this structure are- mass, material, and Specific Energy Absorption (SEA). The results are compared with bumper beam made of mild steel. Three types of materials are used in the present study which consists of mild steel as references material, Aluminum AA5182, E-glass/epoxy composite and carbon fiber/epoxy composite with three different fiber configurations. The beams were subjected to impact loading to determine the internal energy and SEA and to reduce mass of the conventional bumper beam. The in-plane failure behaviors of the composites were evaluated by using Tsai Wu failure criterion. The results for the composite materials are compared to that of the reference material to find the best material with highest SEA. LS-DYNA Finite Element Analysis software was used. The results showed that carbon fiber/epoxy composite bumper can reduce the bumper mass and has highest value of SEA followed by glass fiber/epoxy composite.
Effect of Sonication Time and Clay Loading on Nanoclay Dispersion and Thermal Property of Epoxy-Clay Nanocomposite
Authors: Adinoyi M.J. , Merah Necar , Gasem Zuhair M. , Al-Aqeeli N.
Published: February 2011

The development of nanoclay-epoxy nanocomposite material requires a suitable blending process to be employed. Amongst blending techniques, sonication has been one of the promising means for polymer-clay nanocomposite fabrication. In this study, epoxy-clay nanocomposites with 2, 4 and 5% clay loadings were fabricated using different sonication periods ranging from 5 to 60 minutes. The effect of sonication time and clay loading on the nanocomposite structure was investigated using Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Scanning Electron Micropscope (SEM) and Energy Dispersive Spectroscopy (EDS). Differential Scanning Calorimetry analysis indicated that while clay loading reduced the glass transition temperature (Tg), sonication time did not alter Tg significantly. Upon examining the structure of the resulting nanocomposites both exfoliation and intercalation structures were present, yet, neither structure was fully achieved; evident by the XRD patterns. Nonetheless, the predominant structures for most of the nanocomposites were intercalation. Intergallery spacing of the nanocomposites were enhanced with increased sonication time mainly at 2%wt loading; whereas further increase in nano-clay loading resulted in a reduction of the d-spacing. SEM analysis showed that clay agglomerates were present in the nanocomposites irrespective of the sonication time. However, the analysis revealed that dispersion of clay was better in the nanocomposite fabricated at higher sonication time. From the EDS analysis, the different sites in the nanocomposites’ microstructure were identified which were then correlated with the observation made in the fractographic analysis.
Variation of Mechanical Properties of Epoxy-Clay Nanocomposite with Sonication Time and Clay Loading
Authors: Adinoyi M.J. , Merah Necar , Gasem Zuhair M. , Al-Aqeeli N.
Published: February 2011

Epoxy-clay nanocomposites have recently gained considerable attention due to their interesting physical, thermal and mechanical properties. These properties, however, depend on a number of parameters such as the clay type, clay modifying agent, polymer matrix and the adopted mixing process. In the current work, epoxy-clay nanocomposites were prepared from Araldite GY6010 CRS and Nanomer I.30E nanoclay using different sonication (mixing) periods (5 to 60 minutes) and different concentrations of clay (2 to 5%wt). The effect of sonication time and clay loading on the tensile and hardness properties of the resulting nanocomposites were investigated. The results showed that the ultimate strength and fracture strain of the nanocomposites were below that of the neat epoxy, but the elastic modulus was generally enhanced by the addition of the nano-clay content. Increasing the sonication time enhanced the tensile strength on the expense of reducing the modulus of elasticity. Hardness of the nanocomposites did not show significant change with either the addition of clay or processing under different sonication times.