bluuebunny/crossref_metadata_2025 huggingface dataset:
Shape Factors for Irregular Glass Reinforced Plastic Pipes – An Analytical and Numerical Approach
Authors: Ismail Ikram K. , Seibi Abdennour
Published: February 2011

This paper presents the development of a mathematical model based on curved beam theory of composite pipes with irregular shapes under diametral loading. The analytical solution was validated through finite element models of the same pipe shapes under similar loading conditions. Four shapes (circular, elliptical, rectangular, and egg shaped pipes) were considered in this study. The analytical and finite element results were used to estimate the shape factor defined by the ratio of the maximum tangential stress of an irregular shape over the maximum tangential stress for a circular pipe. Comparison of the load-deflection curves for the four different shapes revealed that the egg pipe is the stiffest among the rest of the pipes while the square shape is the most flexible one. The analytical solution and finite element results were used to determine the shape factor for the four pipe shapes taking into account the circular pipe as the base shape. Both results were in good agreement and can be used as design guidelines for the irregular shapes without resorting to the conduct of any further testing.
Optimizing Processing Parameters and Fiber Size for Kenaf Fiber Reinforced Thermoplastic Polyurethane Composite
Authors: El-Shekeil Y.A. , Sapuan S.M. , Zainudin E.S. , Khalina Abdan
Published: February 2011

In this study, composite of Themoplastic polyurethane (TPU) reinforced with short fiber (Hibiscus Cannabinus) kenaf (KF) were prepared via melt blending method using Haake Polydrive R600 internal mixer. Effect of various processing temperatures, times and speeds on tensile strength was studied, together with effect of various fiber sizes on tensile, flexural properties and impact strength. Optimum blending parameters were 190°C, 11 min, and 40 rpm for temperature, time and speed, respectively. Using the optimum processing parameters TPU-KF composites with different fiber sizes were prepared. Composite sheets were prepared by hot press machine at 190 °C for 10 min. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Tensile and flexural strength were best for fibers between 125-300 micron. Impact strength showed an increasing trend with increasing fiber size.
Producing Particleboard Using of Mixture of Bagasse and Industrial Wood Particles
Authors: Tabarsa Taghi
Published: February 2011

In this study feasibility of using of mixture of bagasse and industrial wood particles for producing single and three layer particleboard . The aim of this study was to consider bagasse as partially substitute particleboard industry raw material. Variables were type of board at two levels (single and three layer), percentage of added bagasse to industrial particles at 4 levels (20%,30%, 40% and 50%) , and press temp. at two levels (165OC and 180 OC ). In producing three layer particleboard wood and bagasse particles were separated and placed in different layers so that bagasse particles were located in the face layers and wood particles were placed in the core of board. But in one layer particleboard bagasse and wood particles were used in the form of mixture. Effect of variables on physical and mechanical properties of particleboard were determined. Results showed that in three layer particleboard physical and mechanical properties were better than single layer particleboard. Increasing press temperature caused improvement in particleboard properties in most cases due to intermeshing and increasing softening wood and bagasse particles. The optimum treatment in this study was found to be adding 50% bagasse and press temperature of 180 OC.
Studies on Development, Bioactivity and Corrosion Behaviour of Nanostructured Titania/Hydroxyapatite Composite Layer on Cp Ti
Authors: Venkateswarlu K. , Nagumothu Rameshbabu , Bose Arumugam Chandra , Muthupandi V. , Subramanian S.
Published: February 2011

Nanostructured titania/hydroxyapatite (HA) composite layer was developed on commercially pure titanium (Cp Ti) implant material by plasma electrolytic processing (PEP) technique in order to improve its bioactivity and corrosion resistance under physiological conditions. The phases present in the developed composite layer were studied by X-ray diffraction (XRD) technique. The surface morphology and thickness of the composite layers were observed by scanning electron microscopy (SEM). The corrosion characteristics of the developed layer were studied by potentiodynamic polarization scan under simulated body fluid (7.4 pH Hanks solution) and simulated osteoclast (4.5 pH) conditions. The in-vitro bioactivity of the composite layers was studied by using Kokubu’s simulated body fluid (SBF) solution. The X-ray diffractograms reveal the presence of anatase TiO2 and HA phases in the developed layer. The SEM results confirm the pore-free morphology of the implant material surface and the thickness of the developed composite layer was observed to be 110 ± 5 µm for 12 min of PEP. The potentiodynamic polarization study shows an improved corrosion resistance and the in-vitro bioactivity test results indicate enhanced apatite forming ability of PEP treated Cp Ti surfaces compared to that of the untreated Cp Ti, under simulated body fluid conditions.
Finite Element Analysis of Fibre Reinforce Concrete Beam Subject to High Temperature by Using EURO-Code Models
Authors: Awad Ziad K. , Yusaf Talal F.
Published: February 2011

Glass fibre composite reinforcement bars have been used in the reinforced concrete structures as a powerful solution of the steel corrosion problem. This research work aims to use a 3D finite element method and EURO – code models to simulate a concrete beam reinforced with fibre composite bars under the effects of high temperature. The behaviour of the structure is very complex due to load combination and different material response. The applied load was an external mechanical load and a thermal load. The material response was considered as thermal expansion, cracking, crushing, yielding and changing of material properties with the temperature increase. The FE element was modified to allow temperature distribution and material properties changing to throw thickness of the concrete beam. In addition, the geometrical non – linearity is considered in the analysis due to the large deflection of the structure. The prediction results were compared with the available experimental results, and it gives a well correspond.
Responses of Aging Treatment to the Behavior of Aluminum Alloy with Addition of 0.02% Zirconium Element
Authors: Zakaria Mohd Syukry , Ismail Ahmad Badri
Published: February 2011

Response of aging treatment on aluminum alloy towards its hardness has been investigated. Alloy used on this research was develop base on a US patent 4121951 that is use to produce aluminum cable with excellent strength and conductivity [1]. Solutioninzing treatment was carried out to the alloy at 520 °C for 2 hours. Alloy then were artificial aged at 180 °C, 200 °C and 220 °C for various periods up to 10 hours. Natural aging also has been carried out for 2 weeks right after solution quenching. By referring to the results, hardness increase as the aging time increase until it reaches the maximum peak and then decreases as the result of overaging. Hardness of artificial aged alloy then was compared with 99.99% pure aluminum, as-cast and naturally aged alloy. Alloy aged at 180 °C for 2 hours give the highest value of hardness which is 34.26 Hv followed by naturally aged alloy and pure aluminum with 30.92 Hv and 15.2 Hv. The effect of different time of artificial aging gives significant change in hardness in order to improve the strength of aluminum alloy. Minor addition of zirconium during the aluminum processing will probably cause by the precipitation of Zr particles towards the aluminum matrix [2], thus increase the strength even these particulate cannot be detected by XRD. These particles will retard the grain movement and also stable upon heating due the low solubility of zirconium in aluminum matrix.
Critical Speeds for Carbon/Epoxy Composite Rotors in Spacecraft Energy Storage Applications
Authors: Varatharajoo Renuganth , Mustapha Faizal , Abdul Majid Dayang Laila Abang , Zahari Rizal , Kahle Ralph
Published: February 2011

A numerical investigation to optimize the carbon/epoxy multi layer composite rotor is performed for the spacecraft energy storage application. A high-speed double and triple layer rotor design is proposed and different composite materials are tested to achieve the most suitable recipe. First, analytical rotor evaluation was performed in order to establish a reliable numerical composite rotor model. Subsequently, finite element analysis is employed in order to optimize the double and triple layer composite rotors. Then, the modal analysis was carried out to determine the rotor natural frequencies. The rotor stress distributions and the rotor mode shapes show that a safe operational regime below 46, 000 rotations per minute is achievable.
Sandwich Composites of Glass Fibre Panel and Polyurethane/Coconut Coir Foam Core (GFRP - PUC)
Authors: Azmi M.A. , Abdullah Hasan Zuhudi , Idris Maizlinda Izwana
Published: February 2011

In this work, sandwich composite properties were investigated by addition of coconut coir (CC). Fibres in the polyurethane foam cores ranges from 0 to 20 wt.%. Glass fibre reinforced epoxy panels were used as a skin and polyurethane foam as a core, these materials adhesively bonded to keep the whole structure attached with each other. Sandwich composite skins and core-skin bonding were attained via adhesive bonding technique. While polyurethane foam reinforced by coconut coir fibres were manufactured by using one shot process and polyurethane moulding method. Sandwich composite panels with different coir fibres compositions were subjected to the density test, weight per area test and flexural testing in order to investigate their physical and mechanical properties. From the experimental results and analysis, it was found that the sandwich composites with 10 wt.% of coir fibres offer higher mechanical properties.
A Semi-Energy Finite Strip Method for Post-Buckling Analysis of Relatively Thick Anti-Symmetric Cross-Ply Laminates
Authors: Hajikazemi Mohammad , Ovesy Hamid Reza , Sadr-Lahidjani Mohammad Homayoun
Published: February 2011

In the current paper, a new semi-energy finite strip method is developed based on the concept of first order shear deformation theory (FSDT) in order to attempt the post-buckling solution for relatively thick composite plates subjected to uniform end-shortening. The main advantage of the semi-energy finite strip method (FSM) is that it is based on the closed form solution of von Karman’s compatibility equation in order to derive the analytical shape functions for the in-plane displacements fields. The developed finite strip method is applied to analyze the post buckling behavior of a relatively thick anti-symmetric cross-ply composite plate with clamped out-of-plane boundary conditions at its loaded ends. The results are discussed in detail and compared with those obtained from finite element method (FEM) of analysis. The study of the results has provided confidence in the validity and capability of the developed finite strip in handling post-buckling problem of relatively thick laminated plates.
Water Retention in Kenaf/Polypropylene Composites due to Repeated Immersion and Drying Conditions
Authors: Haniffah W.H. , Khalina Abdan , Sapuan S.M.
Published: February 2011

Lignocelluloses based natural fibers composites are very prone to water absorption due to OH functional group within cellulose and hemicelluloses of natural fibers. In this work, the water retention in the kenaf/polypropylene (kenaf /PP) composite due to repeated immersion and drying are studied. The composites (40%, 50%, 60% and 70% fiber loading) are immersed in the water and then dried in room condition (24°C and 48 % humidity) for 4 cycles (1 cycle is 10 days of immersion and drying). The parameters are 8\2 (imply 8 days immersion\ 2 days drying), 6\4, 4\6 and 2\8 per cycle. Continuous immersion (100% immersion) is used as a reference of water absorption behavior of the composite. The results for 70% fiber loading under minimum drying days of 8\2, shows that the water retention reduced to 36% from the water absorbed and further drying only reduced to 31%. When the experiment are repeated for several cycles, 70% fiber loading composites shows a decreasing pattern in water retention at the second cycle whereas 40% fiber loading composite showing an increasing pattern. Duration of immersion\drying does play an important role in the amount of water retention in the composite. The water retention of the composites either show an increasing or decreasing pattern depending on kenaf fiber loading and repetition of the immersion\drying for several cycles.
The Effect of Aging Temperature on Mechanical Properties of Banana Pseudostem Fiber Reinforced Polymer Composite
Authors: Zain Siti Nur Zafirah M. , Ismarrubie Z.N. , Zainudin E.S.
Published: February 2011

Polymer composites using natural fibers as the reinforcing agents have found their use in many applications. The initial development of polymer composite based on high density polyethylene (HDPE) with banana pseudostem fiber was studied based on the effect of non-aging and aging treatments. Tensile, flexural and impact tests were performed to investigate the mechanical properties of banana pseudostem fiber reinforced composite. Flexural and impact test results show that the specimen strength improved after aging treatment was applied. However, the tensile test results gave a reverse effect on the strength of the composite after aging. The specimen became more brittle when the composite was exposed to the aging temperature.
Boundary Condition Effects on the Parametric Stability of Moderately Thick Laminated Cylindrical Panels
Authors: Fazilati Jamshid , Ovesy Hamid Reza
Published: February 2011

A Reddy type, third order shear deformation theory of shells is applied to the development of two versions of finite strip method (FSM), namely semi-analytical and spline methods, to predict the parametric stability and instability regions in the case of cylindrical moderately thick composite laminated panels. The structures are assumed to be under harmonic in-plane loads in the context of the so-called parametric loading. The linear strain terms are expressed in terms of the Koiter-Sanders theory of shallow shells. In order to demonstrate the capabilities of the developed methods in predicting parametric behavior of the subject structures, some representative results are obtained and compared with those in the literature wherever available.
Viability of Synthetic Fibers to Replace Steel Wire Mesh in Composite Metal Decks Construction
Authors: Al-Toubat Salah , Ousman Hussein , Barakat Samer , Rieder Klaus Alexander
Published: February 2011

Composite metal decking has become one of the prevalent forms of Fast Track Construction for multi-story steel buildings. The in-plane stiffness of composite metal decks however is of considerable importance as they typically act as a diaphragm in lateral-load- resisting systems and thus attract a large in-plane shear. The diaphragm action or the in-plane shear capacity of composite metal decks remained a concern for structural engineers and designers. The present work aims to investigate the in-plane shear behavior of fiber reinforced composite metal decks and compare it to that reinforced with welded wire mesh. A comprehensive experimental program involving testing large scale slabs was conducted. Steel decking of trapezoidal profile with a sheet thickness of 0.9 mm was used to construct the composite slabs. Conventional WWF mesh reinforcement and synthetic macro fibers at different reinforcing rates were considered in the test program. The slabs were tested under monotonically increasing in-plane shear force until failure. Load-deflection responses were plotted and cracking pattern and sequence were recorded. The test results show that fibers provide comparable deck behavior as that with steel mesh. Both imparted similar ultimate in-plane shear capacity and enhanced the ductility and the post peak behavior of the composite metal decks relative to the control slab. The results demonstrate the viability of synthetic macro fibers to replace the steel mesh in this type of composite flooring systems.
Optimization of Injection Parameters Using 16µm Stainless Steel Powder (SS316L) at 63 Vol. %, 63.5 Vol. % and 64 Vol. % Powder Loading by Taguchi Method for Metal Injection Molding
Authors: Chua Abdullah Muhammad Ilman Hakimi , Sulong Abu Bakar , Muhamad Norhamidi , Abdullah Mohd Fazuri , Che Haron Che Hassan
Published: February 2011

In this paper, injection molding parameters are optimized using the L18 Taguchi orthogonal array for mechanical strength and surface quality of the green part. The feedstock used consists of stainless steel powder (SS316L) with the powder loading of 63 vol. %, 63.5 vol. % & 64 vol. %. The binder compositions used are polyethelene glycol (PEG-73 wt.%), polymethyl methacrilate (PMMA-25 wt.%) and stearic acid (4 wt.%). Mould temperature, injection temperature, injection pressure, injection time, holding time and powder loading ware selected as signal factors using Taghuci’s method based on literature, where these parameters were significant in MIM. Results showed that the optimum parameters are: mold temperature at 650C, injection temperature at1450C, injection pressure at 650 bar, injection flow rate at 20 m3/s, holding time at 5 s and powder loading of 64 vol.%. Analysis of Variance (ANOVA) result shown that mold temperature is the most influence in order to produce good green part’s surface quality while powder loading give the best result for green part’s strength.
The Influence of Recycled Poly(ethylene Terephthalate) Powder on Fatigue Life, Thermal Stability, and Morphology of Halloysite Nanotubes (HNTs) and Precipitated Silica Filled Natural Rubber Composites
Authors: Nabil H. , Hanafi Ismail , Azura A.R.
Published: February 2011

In this paper, the influence of recycled polyethylene terephthalate powder (R-PET) on fatigue life, thermal properties and micro-fracture surfaces of halloysite nanotubes (HNTs) and silica filled natural rubber composites have been studied. The total amount of hybrid filler in each formulation was kept constant at 20 parts per hundred rubber (phr). The final properties of HNTs/R-PET and Silica/R-PET compounds are considered separately and comparatively. Results indicated that the fatigue life of the natural rubber composites decreased with the replacement of these two fillers by R-PET powder. This observation might be due to the R-PET itself, which reduces the interfacial adhesion and wettability between rubber matrix and fillers. By replacing of HNTs and silica with R-PET powder, the thermal degradation of natural rubber composites was shifted to a lower temperature and the char residues was decreased, in which HNTs/R-PET composites expressed the higher temperature and char residues than silica/R-PET composites. This findings may be due to the HNTs/R-PET has less volatile matter than silica/R-PET that might enhance the degradation temperature of the natural rubber composites. SEM micrographs also exhibited weak interfacial adhesion when these two fillers were replaced with R-PET powder in NR composites.
Optimizing Processing Parameters for Hybridized Kenaf/PALF Reinforced HDPE Composite
Authors: Aji I.S. , Zainuddin E.S. , Khalina Abdan , Sapuan S.M.
Published: February 2011

This work is aimed at achieving optimum processing parameters for Kenaf/PALF/HDPE. Processing parameters like temperature, speed of rotor and duration of composite mixing in an internal mixer were examined. Oven conditioned and unconditioned specimen were prepared and tested. The best tensile strength and tensile modulus were obtained at an optimum processing parameters of 190oC, 40rpm, and 15min for temperature of processing, speed of rotor and duration of mixing respectively, while 190oC, 40rpm and 20min gave the best flexural strength and 190oC, 40rpm and 25min for flexural modulus. Conditioning of composite tends to reduce its tensile modulus while increasing its strength and flexural modulus. All samples were produced at only 10w%(mass) of fibre in the composite at 1:1 and less than 0.3mm fibre ratio and length respectively. Utilization of these parameters according to end requirement can help in achieving optimum mechanical properties on hybridized composites.
A Novel Phenol – Based Composite Production: Features and Characterization
Authors: Ganji Marzieh , Tabarsa Taghi
Published: February 2011

The aim of this study is to investigate on manufacturing new tannin phenol-formaldehyde resin as adhesive in paulownia composite. For this purpose, renewable tannin was introduced in the classic adhesive formulation in order to supply a part of phenol–formaldehyde (PF). Variables were substituted tannin with phenol at two levels (0%, 10 % and 20%) and press temperature (150Co and 170Co). plywood panels were manufactured in laboratory. Mechanical (MOR and MOE and) and physical (TS and WA) properties of panels were evaluated according to ASTM standard. Data collected based on factorial design and using SPSS software were analyzed. The Results showed that substitution tannin with phenol had slight effect on mechanical properties but when press temperature increased mechanical properties were improved. Physical properties of plywood panels bonded with tannin–PF resins (20:80) were better than plywood panels PF made.
Friction Forces between Sheet Molding Compound Charge and Mold Cavity Surface in Compression Molding
Authors: Shokrieh Mahmood M. , Mosalmani Reza
Published: February 2011

In this study, three relevant friction ‎forces: constant friction force, hydrodynamic friction force and coulomb friction force are ‎considered between sheet molding compound (SMC) charge and contact surface of the mold. The power ‎law model is implemented to propose a model for prediction of hydrodynamic friction as the dominant friction of the SMC compression molding. The proposed model ‎is simple and does not need any extra experimental parameters. Finally, a model has been developed to predict the molding pressure under non-isothermal conditions. The obtained results of the model are in a very good agreement with the experimental data.
Characterization of Tantalum Carbide Reinforced Copper Composite Developed Using Mechanical Alloying
Authors: Salleh Emee Marina , Hussain Zuhailawati
Published: February 2011

The effects of the consolidation pressure on the properties of novel Cu-15vol% TaC composite was investigated. The copper-based composite has been prepared using a high energy planetary mill via in-situ route. A mixture of copper, tantalum and graphite powder was mechanically alloyed for milling time of 8 hours at speed of 400 rpm. The as-milled powder was consolidated by cold pressing under various pressure (i.e. 100, 200, 300 and 400 MPa) at room temperature and sintered in argon atmosphere at 900 °C for an hour. TaC phase was formed in copper matrix after sintering process. An increase in consolidation pressure resulted in an increase in hardness, electrical conductivity and density of the composites. The changes of bulk properties of the in-situ Cu-TaC composite were correlated to the formation of TaC phase and a reduction of porosity which led to an increasing in densification.
The Effect of Chitosan Loading on the Properties of Chitosan Filled Epoxidized Natural Rubber Compounds
Authors: Shaari S.M. , Hanafi Ismail , Othman Nadras
Published: February 2011

The study of chitosan loading onto epoxidized natural rubber compounds were prepared by incorporation of chitosan into epoxidised natural rubber matrix using a two-roll mill. The effects of chitosan loading on the curing characteristics, tensile properties and morphology of the compounds were investigated. Results indicated that slight changes in curing time (t90), and scorch time (tS2) of the compounds with the incorporation of chitosan. An increment is observed in the maximum torque, tensile modulus and durometer hardness of the compounds while tensile strength and elongation at break declines with chitosan loading.
Influence of Mixed-Mode Ratio on Delamination Fracture Toughness and Energy Release Rate of Glass/Polyester Laminates
Authors: Khoramshahi Astiaj , Choupani Naghdali
Published: February 2011

Glass fiber reinforced materials are particularly attractive for transportation industries because of their high strength/mass ratio and their low cost compared to other materials. Therefore, the composite material system used in this study consists of polyester resin layers reinforced with E-glass fabrics. In this paper, the effect of mixed-mode loading on fracture parameters of glass reinforced polyester composite specimens is investigated both experimentally and numerically. Geometric factors were calculated for modified Arcan specimen using finite element analysis. The finite element results indicated that for loading angles close to pure mode-II loading, a high ratio of mode-II to mode-I fracture is dominant and there is an opposite trend for loading angles close to pure mode-I loading. According to experimentally measured fracture toughness for glass/polyester, the opening-mode and shearing mode interlaminar critical strain energy release rates, were found. Results indicated that the interlaminar cracked specimen is tougher in shear loading condition and weaker in tensile loading conditions.
Experimental and Numerical Investigation of the Mixed-Mode Delamination of PAN Based Carbon/Epoxy Composite Using Modified Arcan Fixture
Authors: Ziaee M. , Choupani Naghdali
Published: February 2011

The present research examines analytically and experimentally the mode-I and mode-II and mixed mode-Interlaminar fracture toughness of PAN based carbon/epoxy composite. A modified Arcan fixture, well-suited for the study of the behavior of used composite assemblies, was developed in order to focus on the analysis of the fracture behavior of the material. The edge effects are minimized by using an appropriate design of the substrates so that experimental results give reliable data. Also the mode-I and mode-II stress intensity factors were computed for different crack lengths and load orientation angles using finite element analysis. The numerical results show that the modified Arcan specimen is able to provide pure mode-I, pure mode-II and any mixed mode loading conditions. It is shown that the results obtained from the fracture tests are consistent very well with mixed mode fracture theories. Obtained results indicated that fracture toughness and stress intensity factor for sliding mode enhanced up when the loading angle increased. Mechanism of fracture and toughening were examined by using scanning electron microscopy.
Acoustic Emission Localization in a Composite Stiffened Panel Using a Time Reversal Algorithm
Authors: Ciampa Francesco , Meo Michele
Published: February 2011

This research work presents an in-situ imaging method for the localization of the impact point in complex anisotropic structures with diffuse field conditions, using only one passive transducer. The proposed technique is based on the time reversal approach applied to a number of waveforms stored into a database containing the experimental Green’s function of the medium. The present method exploits the benefits of multiple scattering, mode conversion and boundaries reflections to achieve the focusing of the source with high resolution. The optimal re-focusing of the back propagated wave field at the impact point is accomplished through a “virtual” imaging process, which does not require any iterative algorithms and a priori knowledge of the mechanical properties of the structure. The robustness of the time reversal method is experimentally demonstrated on a stiffened composite panel and the source position can be retrieved with a high level of accuracy (error less than 3%). The simple configuration, minimal processing requirements and computational time (less than 1 sec) make this method a valid alternative to the conventional imaging structural health monitoring systems for the acoustic emission source localization.
Multiscale Modeling of Hybrid Composite Structures
Authors: Růžička Milan , Had Jiří , Kulíšek Viktor , Uher Ondřej
Published: February 2011

A novel type of hybrid composite structure has been developed, experimentally investigated and used for many practical applications. The main supporting elements of composite structures are formed by the stamping process of partially cured and axially-oriented carbon fibre rods. This system can fill relatively thick parts of cross sections of beams without risk of delamination. Typical macroscopic sub-cells are formed in the transversal cross section of the part due to this technology. An advantage of this final 3D composite structure is its high shear strength and stiffness in comparison with thick unidirectional composite parts. To absorb the dynamic energy and increase the damping, a rubber-cork layer can be inserted during production, before the final pressing and curing of the whole part. The final stiffness property of the whole 3D composite is obtained from multiscale modeling. It is based on an averaging process and a homogenization technique in FEA. A parametric study was carried out to determine the influence of the size, orientation and thickness of the cell border winding layer on the components of the global elastic material matrix. A comparison of a numerical analysis prediction with experimental results shows acceptable agreement of the elastic modules. A mezzo scale model can be applied for designing a real part on a macro scale.
Microstructure Characterisation of Ag2O3-Bi2O3 Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs)
Authors: Dedikarni Dedikarni , Muchtar Andanastuti , Muhamad Norhamidi , Wan Daud Wan Ramli
Published: February 2011

Porous Ag-Bi2O3 composite cathodes on stainless steel (SS) substrate, an excellent mixed-ionic conductor that can be used as cathode material for the intermediate temperature solid oxide fuel cell (IT-SOFC) has been developed using the slurry painting method. Characterisation of the composite cathode includes the thermal analysis, morphology, and porosity of the porous cathode. Thermal analysis of the dried slurry was conducted in order to determine the heating schedule for eliminating the organic components using thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The TGA and DSC analyses confirmed the organic vehicle was fully decomposed below 418oC and the formation of composite cathode oxide phase took place beyond 600oC. The microstructure of the thermally treated cathode was analysed using SEM and XRD. The SEM results showed that the grain size of the cathode increased with the increase of temperature during thermal treatment and the X-ray diffraction (XRD) analyses confirmed the presence of δ-Bi2O3 phase on the cathode. Porosity was obtained using the Archimedes method. The Ag2O3-Bi2O3 cathode on stainless steel substrates was found to have a porosity of 53%, 51%, 39% and 28% upon 1, 2, 3, and 4 coatings, respectively, as well as thermal treatment at 800°C for 1 hour.
Effect of Compression with Oscillatory Torsion Processing on Structure and Properties of Cu
Authors: Rodak Kinga , Pawlicki Jacek , Radwański Krzysztof , Molak Rafal M.
Published: February 2011

In this study, commercial Cu was subjected to plastic deformation by compression with oscillatory torsion. Different deformation parameters were adopted to study their effects on the microstructure and mechanical properties of Cu. The deformed microstructure was characterized by using scanning electron microscopy (SEM) equipment with electron backscattered diffraction (EBSD) facility and scanning transmission electron microscopy (STEM). The mechanical properties were determined on an MTS QTest/10 machine equipped with digital image correlation. Can be found, that process performed at high compression rate and high torsion frequency is recommended for the refining grain size. The size of structure elements: average grain size (D) and subgrain size (d) reached 0.42 m and 0.30 m respectively, and the fraction of high angle boundaries was 35%, when the sample was deformed at a torsion frequency f= 1.6 Hz and compression rate v=0.04 mm/s. Deformation at these parameters leads to an improvement in strength properties. The strength properties are about two times greater than the initial state.
Ultrafine Grained Copper Alloys Processed by Continuous Repetitive Corrugation and Straightening Method
Authors: Głuchowski Wojciech , Stobrawa Jerzy , Rdzawski Zbigniew , Malec Witold
Published: February 2011

A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with ultrafine grain size of a copper matrix. This study was aimed to investigate mechanical properties, electrical conductivity and microstructure in strips of precipitation strengthened copper alloys processed by continuous repetitive corrugation and straightening (CRCS). Tests were performed with the copper alloy strips using original die set construction installed on tensile testing machine. The microstructure was investigated using optical and electron microscopy (TEM and SEM equipped with EBSD). Proposition of semi industrial application of this method have been also presented. The CRCS process effectively reduced the grain size of a copper alloy strips, demonstrating the CRCS as a promising new method for producing ultra fine grained metallic strips.
Novel Temperature Sensor Fabricated with Oxide and Metal
Authors: Jeon Ho Sik , Cho Seung Hyun , Heo Yang Wook , Bae Byung Seong
Published: February 2011

Resistance of metal depends on temperature. Therefore, the metal can be used as a temperature sensor with a reference resistor. The reference resistor is connected serially and the voltages of the sensor metal are measured after applying DC voltage. However, it is not easy to keep the reference resistance constant while measuring temperatures. We studied the temperature dependence of resistance of oxide material to apply it to the bridge type temperature sensor which is insensitive to the environmental temperature. We made bridge type temperature sensor with oxide material and metal. The novel temperature sensor does not need a reference resistor, and composed of oxide and metal. Therefore, we could remove error induced by environmental temperature variation. Moreover, the novel bridge type temperature sensor provides higher sensitivity than conventional sensor structure. By different thermal coefficient of the oxide material, it was possible to remove an external reference resistance. The proposed bridge type temperature sensor is a self-reference temperature sensor which is insensitive to the environmental temperature.
Magnetic Nanotubes as an Element in Biocomposites
Authors: Kalska Szostko Beata , Brancewicz Ewa , Orzechowska E. , Mazalski Piotr , Wojciechowski T.
Published: February 2011

In this work magnetic nanorods have been synthesized by electrodeposition inside the nanotubes fixed to anodic alumina oxide (AAO). The used templates have the pore diameter of 120 nm. In the first step different combinations of 3d elements oxide nanotubes such as: CoO, NiO, NiFe2O4, CoFe2O4 and Fe3O4, have been successfully fabricated inside the nanopores by wetting chemical deposition followed by thermal decomposition. Oxide/Fe, wires were obtained in the next step by electrodeposition The morphology of obtained structures were studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The magnetic properties of the nanostructures were determined on the base of behavior of the structures in external magnetic field. Local magnetic moment orientation is not strictly determined up to now. The potential biological application as an enzyme carrier was tested.
Influence of Grain Refining on Abrasive Wear of Submicrocrystalline Al-Si Alloys
Authors: Dybiec Henryk , Motyka Maciej
Published: February 2011

Light weight nano/submicrocrystalline materials are promising group of constructional materials combining low density with high mechanical properties. However, their potential application requires extensive testing of functional properties, e.g. tribological ones, which may be significant and determine their practical use. Available information on abrasive wear and friction coefficients in nano/submicrocrystalline materials is rather poor. Therefore the aim of this paper is to fill the gap in the literature in this field. The AlSi12Fe5Cu3Mg alloy (RS422) produced by rapid solidification and plastic consolidation with grain size of basic phase components in the range from 50 nm to 300 nm was examined. Microstructure and mechanical properties of the materials were determined. Abrasive wear tests, static and kinematics friction coefficients measurement were carried out under the surface condition including dry, wet and oil lubricant. The results have been compared to the values of similar quantities determined in the same conditions for conventionally produced alloy AlSi11FeCuMn (AK11). Substantial increase of friction coefficients for RS442 comparing to AlSi11FeCuMn material was found, however, abrasive wear for nano/submicron grained materials were low in comparison to conventional one. Considerable increase of abrasive wear at water presence and very weak attrition at oil lubrication was observed. Relationship between structure and mechanical properties of tested materials was analyzed.
Viscosity of Sn-Cu Solders Investigated by Molecular Dynamics
Authors: Ding Rui Fang , Pan Xue Min , Wei Guang Ling
Published: February 2011

The self-diffusion coefficient of Cu in Sn-1.5wt.%Cu and Sn-2wt.%Cu lead-free solders was investigated using molecular dynamics simulations based on a modified embedded-atom method from 503 K to 773 K. Then the viscosity of the solders was calculated using the selfdiffusion coefficient values, and the results were in good agreement with the experimental data. Two segments, a low-temperature zone and a high-temperature zone, were found on both η–T and lnη–1/T plots, where η is the viscosity and T is the absolute temperature. Through analysis, we infer that the viscosity mutation was attributed to the remarkable structure transition.
Synthesis and Performance of Perovskite YMnxFe1-xO3 Photocatalyst
Authors: Zhang Hui , Lü Xiao Meng , Ding Jian Lin , Xie Ji Min , Yan Chang Hao
Published: February 2011

Using Y2O3, Mn(CH3COO)2·4H2O as raw materials and glacial acetic acid as solvents, YMnxFe1-xO3 precursors (x= 0, 0.05, 0.1, 0.3, 0.5) have been prepared under 80°C water bath conditions. Perovskite YMnxFe1-xO3 samples were achieved after calcination over 900 °C for 4 h. Structure of the samples was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Ultraviolet obvious diffuse reflection(UV-vis DRS), and Field-emission scanning electron microscopy (FESEM). Photocatalytic activity of the samples was also investigated. Results showed that all the samples with stable perovskite structure had high light absorption in visible-light region, suggesting good visible light harvesting. SEM image showed that the samples were sponge-like and porous agglomerates. Photodecoloration activity of 100 mL Rhodamine B (10 mg/L) was 16~56 % under illumination for 150 min. Oxygen vacancies of the perovskite may explain the high activity of x = 0.1 sample.
Synergy Effect of Ce/N Co-Doping on Anatase TiO2 Photocatalysts from First Principles Calculation
Authors: Yao Xiao Jie , Yao Man , Wang Xu Dong
Published: February 2011

Recent experiments have indicated that TiO2 co-doped with cerium (Ce) and nitrogen (N) may show enhanced photocatalytic activity in the visible region with respect to TiO2 doped only with Ce. Prompted by these findings, we have investigated Ce-N co-doped TiO2 through a theoretical study. Density functional theory (DFT) calculations have been carried out with the generalized gradient approximation (GGA) to describe the electronic structure and photocatalytic activity of Ce-, N- and N/Ce-doped anatase TiO2; substitutional locations of Ce and N in the TiO2 lattice were considered: an O (Ti) atom is replaced by an N (Ce) atom. It was found that the Ce-N co-doped case narrows the band gap more significantly than the corresponding mono-doped anatase TiO2. These findings give the theoretical understanding for recent experimental results.
Adsorption of H2S and SO2 on Activated Carbon Fibers Modified by Ammonium Nitrate
Authors: He Da Song , Liu Cun Ping , Guo Sheng , Li Xiu Ying
Published: February 2011

The enhancement effect of using PAN-based carbon fibers surface modified by ammonium nitrate for removing SO2 and H2S in moist air at room temperature was characterized and investigated. The pore structure of the samples so prepared was examined by adsorption measurement. Surface groups introduced by treatment with ammonium nitrate was assessed by xray photoelectron spectroscopy. The results show that the amount of sulfur dioxide and hydrogen sulfide adsorbed with the treated carbon fibers are increased by 112% and 93% and ammonium nitrate treatment improved original carbon fibers adsorption performance, not only by introducing nitrogen surface groups, but also by extending the surface area.
A New Smart Damage Sensor Using Mechanoluminescence Material
Authors: Wang Wen Xue , Imai Yusuke , Xu C.N. , Matsubara T. , Takao Y.
Published: February 2011

This paper proposes a new smart sensor for the detection of damage in structures using mechanoluminescence (ML) material SrAl2O4:Eu (SAOE). SAOE is a kind of functional ceramics that can emit visual light when it is subjected to external mechanical action. The luminescence of SAOE is very high so that it enables us to view the visual light with naked eye. A smart film sensor is fabricated using SAOE powder and polymer. The effect of load frequency on the emitted visual light is investigated under cyclic loading conditions. Furthermore, detection of a crack and evaluation of the stress concentration and stress intensity factors are performed using SAOE film sensor. Experimental results demonstrate that the visual light emitted by SAOE film sensor has good correlation with the equivalent strain and stress.
Quantitatively Characterizing Damages on Steel Beams by Using PZT Impedance Method
Authors: Qiao Hai Yan , Li Ji Cheng , Lin Li , Li Xi Meng
Published: February 2011

The PZT-based electro-mechanical (E/M) method was utilized to measure the impedance of a 1-D steel beam with cracks introducing and developing. Quantitatively assessment of cracks was made by using damage metrics Root Mean Square Deviation (RMSD) and Covariance (Cov). Changes in the coupled impedance of PZT and the beam (500mm×20mm×6mm) were investigated during the appearance and extension of cracks. With the depth of crack dc increasing from 0.6mm to 1.8mm, the peaks of impedance spectrum shifted to lower frequency in the frequency range of 182 kHz-370 kHz and the amplitude showed a decreasing tendency. Moreover, the initial crack brought more significant changes in impedance than that from the developing of cracks. The relationships between dc and RMSD/Cov were investigated. It was proved that RMSD and Cov were efficient in quantitatively presenting the extension of cracks on the 1-D beam.
Study on the Temperature-Sensitive Properties of Carbon Fiber-Reinforced Mortar
Authors: Liu Xiao Yan , Liu Ai Hua , Wei Feng , Yao Wu
Published: February 2011

Carbon fiber (~5mm long)-reinforced mortar is found to be an effective thermal sensor. In this paper, relations between temperature change and resistivity of carbon fiber- reinforced mortar (CFRM for short) with different carbon fiber contents (0.4%~1.2% by mass of cement) are studied. The results show that during the initial period, the resistivity decreases when the temperature increases (Negative Temperature Coefficient effect). After the temperature reaches a certain value, the resistivity increases when the temperature increases (Positive Temperature Coefficient effect). Besides, with the change of carbon fiber content, the transit temperature of NTC/ PTC effect also changes. Based on the experimental results, the CFRM shows a potential use as a thermal sensor. The mechanisms of temperature- sensitive properties and NTC/ PTC transition are also discussed.
Preparation and Characteristics of Integral Water Repellent Cement-Based Materials
Authors: Zhang Peng , Zhao Tie Jun , Wittmann F.H. , Li Shao Chun
Published: February 2011

Polymers are often applied in concrete for multiple purposes and aims. For instance, surface impregnation of concrete with silanes is a reliable technology to protect cement-based materials from ingress of aggressive solutions into the materials. An alternative method is to add silane emulsion into fresh concrete or mortar to produce integral water repellent materials. In this contribution integral water repellent concrete was prepared by adding 1 %, 2 %, 3 %, 4 % and 6 % of silane emulsion. The influence of silane emulsion on the compressive strength, porosity and pore size distribution, water capillary suction and chloride penetration have been investigated. The results indicate that addition of silane emulsion moderately reduced compressive strength of concrete. With 3 % of silane emulsion the reduction is about 10 %. The addition of silane emulsion hardly has influence on pore size distribution. Silane does not block the capillary pores, but only forms a hydrophobic film on the walls of capillary pores. Addition of silane emulsion reduces water capillary suction significantly. The reduction rate is higher than 89 %. Even the surface of integral water repellent concrete is abraded off 7 mm, the material still demonstrates high water repellency because the entire volume is hydrophobic. In addition, chloride penetration also can be reduced substantially.
The Fabrication of W-Cu Modified Layers on the Surface of the Continuous Casting Machine Mould Copper Plate by Infiltration
Authors: Ma Hai Tao , Huang Wen Ping , Wang Lai
Published: February 2011

In this paper, a new method named infiltration was applied to fabricate W-Cu surface modified layers of copper mould firstly in order to promote the life span of the continuous casting machine (CCM) mould. Our efforts concentrated on fabricating the W-Cu modified layers on the surface of mould copper plate by presintering and infiltration under inert gases. The W particle size and sintering temperature of W skeleton were adjusted to gain homogeneous microstructure of W-Cu modified layers. The results show that homogeneous microstructure of W-Cu modified layers can be obtained with the method of presintering and infiltration. For the excellent microstructure of W-Cu modified layers, the suitable tungsten particle size is 300 meshes and the optimal presintering temperature is about 1300°C. W-Cu modified layers have good bonding strength with copper substrate.
Preparation and Electrical Properties of the Polyimide/Multi-Walled Carbon Nanotubes (MWNTs) Nanocomposites
Authors: Zhang Ming Yan , Zhu Xiao Ying , Diao Peng He , Wang Wen Jia , Li Xiao Dong
Published: February 2011

The polyimide/multi-walled carbon nanotubes (MWNTs) nanocomposite films were prepared by means of ultrasonic blending and in-situ polymerization. MWNTs were modified with mixed strong acid in order to improve the chemical compatibility between polyimide matrix and MWNTs. The effects of the incorporation of MWNTs on the electrical property were researched in this study. The results showed that with the increase of the content of acid-modified MWNTs, the dielectric strength decreased gradually and had a sharp drop when the addition content was close to 0.6 wt%, the dielectric constant and the dielectric loss factor increased obviously. With the rise of the test frequency, the dielectric constant declined slowly and the dielectric loss factor increased. The corona resistance time of the nanocomposite films was all higher than that of the pure polyimide.