bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Deposition of Metallic Lead Particle Film
Authors: Cheng Jin , Zou Xiao Ping , Meng Xiang Min , Yang Gang Qiang , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

The preparation of metallic lead films by electrochemical deposition was reported. Although primary deposits at fresh state (also referred to as fresh deposits) were indeed metallic lead films, the fresh lead films could be rapidly oxidized to lead oxide in air. To obtain long stable metallic lead films, the key process is how to prevent the oxidization of fresh lead films. Our studies indicate that the washing of fresh metallic lead films in absolute alcohol is a simple but effective method to protect the lead films from the oxidization for an extended period of more than 20 days.
Effect of Ni Addition on In Situ WC-Cr3C2 Cermet Coating by Laser Controlled Reactive Synthesisuse
Authors: Li Wen Ge , Wu Qian Lin
Published: August 2010

WC-Cr3C2 cermet coating on carbon steel was fabricated by laser controlled reactive synthesis and exhibited the metallurgical bonding at the interface between coating and substrate. Experimental results show that addition of Ni results in a significant change on phases and microstructure of coating. Ni addition remarkable improves resistance to thermal shock of coating. This is accounted for by increasing planar crystal zone of the coating due to Ni addition, which decreases stress concentration at the interface.
Self-Organization of Macromolecules in Novel TPU-Clay Nanocomposites
Authors: Mondal Manas , Chattopadhyay Pijush Kanti , Setua D.K. , Das N.C. , Chattopadhyay S.
Published: August 2010

Nanoscale and crystalline morphology of TPU nanocomposites bearing MMT and laponite clays were studied. Laponite was dual modified using ionic and covalent modifications by different silanes. TPU-clay nanocomposites having variegated modified clays, prepared by solution casting, were characterized using TEM, SAXS, variable temperature XRD (VTXRD), and MDSC. TEM show the uniform clay dispersion in MMT nanocomposites as compared to laponite composites. SAXS showed satisfactory fitment of Guinier eqn. at lower q values. Fitment of Porod eqn. is inferior owing to contribution of internal microstructures and interfacial roughness. VTXRD (1400C to 250C at constant cooling rate) and MDSC studies revealed crystalline morphology development in annealed samples that can be related to the aspect ratio, microstructure, and functional grs of clays. The overall crystallinity development is less effected in laponite based composites.
Thermal Relaxations of Polymers Revealed by Reversing and Non-Reversing Coefficient of Thermal Expansion
Authors: Shanks Robert A.
Published: August 2010

Reversible and irreversible events can be resolved) using modulated temperature DSC and TMA. Each technique has advantages, those for TMA include longer times and slower scan rates that allow greater approach to material equilibrium. The thermal expansion coefficient and glass transition temperature can be isolated from relaxations and structural changes. Modulated temperature thermomechanometry (mT-TM) is used to characterize amorphous thermoplastics including PS, PMMA, PC and PPO, and the results including annealing, heating and cooling.
Effect of Process Condition in the Centrifugal Casting on the Mechanical Behavior of Cr Heat Resisting Steel
Authors: Chung Hyup Jae , Rhee Kyong Yop
Published: August 2010

In the present study, the effects of forging or ring-mill processing on the tensile properties of B7B4 were investigated. Tensile specimens were fabricated including centrifugal casting (Case 1), centrifugal casting + forging (Case 2), and centrifugal casting + ring-mill (Case 3). Tensile tests were performed at room temperature. An optical microscope and a scanning electron microscope (SEM) were used to examine the changes in the microstructures of the specimens prepared by the three processes. The results showed that the moduli of elasticity and yield stresses of B7B4 prepared by the three processes had no much difference. The elongations of Case 2 and Case 3 were 30% higher than that of Case 1. SEM images revealed that the orientation and fine structure were affected by the forging and ring-mill processes.
Evaluation and Preparation of PET Aluminum Foil/PLA Nonwoven Compound Fabric as Electromagnetic Shielding Effectiveness Protective Clothing
Authors: Lin Chin Mei , Huang Yu Tien , Yang Yi Chang , Lin Ching Wen , Lou Ching Wen , Lin Jia Horng
Published: August 2010

This study designed a flexible electromagnetic resistant fabric it is not only apt to make protective clothing, but also simple process dependence on its application. Polylactide fiber (PLA) and the low melting polylactide fiber (LMPLA) were blended to fabricate nonwoven matrix. Then polyester (PET) aluminum foil inserted between two layers of PLA nonwoven matrix to fabricate a compound matrix by needle punching. Afterward, physical properties and electromagnetic shielding effectiveness of different layers compound matrix were be evaluated.The result indicated that Tensile strength of sample B was 189.16 N; tear strength of sample C was 579.43 N. Burst strength of sample B which was laminated five-layers compound matrix had best burst strength, 3326.18 N, and excellent electromagnetic shielding effectiveness, over 90 dB.
Study for Bubble Dynamics of Nucleate Boiling in Narrow Channels
Authors: Guo Lei , Zhang Shu Sheng , Cheng Lin
Published: August 2010

Two different types of channels are investigated which have I- and Z-shaped cross-sections with a width of 2mm. Using the numerical simulation method, the influence of wall contact angle to the process of bubble generating and growth up is studied, and the relationship between different channel shapes and pressure drop is also investigated. In the calculation process, the effects of gravity, surface tension and wall adhesion are taken into account. It is found that wall contact angle has a great influence to the morphology of bubbles. The smaller the wall contact angle is, the rounder the bubbles are, and the shorter the bubbles take to departure from the wall, otherwise, the bubbles are more difficult to depart. The variation of contact angle also has effect upon the heat transfer coefficient, the greater the wall contact angle is, the larger bubble-covered area is, thus the wall thermal resistance gets higher, and the heat transfer coefficient becomes lower. The role of surface tension in the process of boiling heat transfer is much larger than the gravity in narrow channels. The generation of bubbles dramatically disturbs the boundary layer, and the bubble bottom micro-layer can enhance the heat transfer. The heat transfer coefficient of Z-shaped channels is larger than that of I-shaped channels, while the pressure drop of the former is obviously higher.
The Effect of Thickness on the Magnetic Anisotropy and Magnetic Properties of Single-Layered FePt Films by In Situ Annealing
Authors: Chen Sheng Chi , Sun T.H. , Chang C.L. , Shen Chih Long , Lin G.P. , Huang K.T. , Ou S.L. , Kuo Po Cheng
Published: August 2010

The FePt films with various thicknesses of 5 to 50 nm are deposited on Si(100) substrate without any underlayer by in-situ annealing at substrate temperature (Ts) of 620°C. A strong (001) texture of L10 FePt film is obtained and presents high perpendicular magnetic anisotropy as the film thickness increases to 30 nm. Further increasing the thickness to above 30 nm, the (111) orientation of L10 FePt is enhanced greatly, indicating that the quality of perpendicular magnetic anisotropy degrades when the FePt film is thicker than 30 nm. The single-layered FePt film with thickness of 30 nm by in-situ depositing at 620°C shows good perpendicular magnetic properties (perpendicular coercivity of 14.0 kOe, saturation magnetization of 473 emu/cm3 and perpendicular squareness of 0.96, respectively), which reveal its significant potential as perpendicular magnetic recording media for high-density recording.
An Investigation on the Local Structure of Silicon: Liquid to Undercooled Regime
Authors: Dalgıç Seyfettin , Colakogullari Mutlu
Published: August 2010

We present the modelled local structure for undercooled silicon beginning from its liquid state, ~1730K to ~1550K. The modelling procedure was achieved by using reverse Monte Carlo (RMC) modelling technique fitting to x-ray static structure factors. The calculated radial distribution functions satisfied experimental observes either liquid or undercooled region. To make a detailed analysis on the modelled local environment we have focused on the distributions both average numbers of atoms within first coordination shell and bond angles whereas the uniqueness of model is discussible. In order to construct model that is more close to nature, the minimum and maximum bond lengths and the average coordination number constraints could have been used. The predicted results using RMC technique show that there is a possible structural transition and it slightly transforms into covalent-like bounded open network structure from its metallic structure, while decreasing temperature.
Determination of Number of Layers and Stacking Sequence of Composite Bicycle Frame
Authors: Jung Hyung Jin , Lee Jin Ah , Kim Ka Yeon , Chun Heoung Jae
Published: August 2010

Due to the high specific strength, high specific modulus and good fatigue characteristics, carbon/epoxy composite bicycle frame can have superior performance to aluminum bicycle. As the strength of composite frame varies according to the number of layers and stacking sequence, it is necessary to determine the appropriate number of layers and stacking sequence for designing light weight composite frame. The frame is divided into six parts, i.e. head tube, seat tube, top tube, bottom tube, seat stay, and chain stay parts. Since different stress levels are generated among the different parts, different numbers of layer with different stacking sequences are considered for each part. Three different loading conditions, i.e. horizontal loading, vertical loading, and pedal loading, are considered in the analysis. The superb stacking sequence and number of layers of the composite frame with the lowest failure index were determined which satisfy the three different loading conditions.
Fracture Failure Analysis of Twin Rolling Casting Magnesium by Hot Compression
Authors: Wang Shou Ren , Yang Li Ying , Ma Ru , Guo Pei Quan
Published: August 2010

The flow stresses of AZ41M and ZK 60 wrought magnesium alloys under the deformation conditions of twin rolling casting and hot compression (TRC-HC) at different temperature and strain rates were studied. The deformation behavior and failure mechanism of them were discussed. The microstructure evolutions were analyzed by OM and EBSD technique. The results indicated that AZ41M and ZK 60 have different strain-stress curve under the same conditions. Working hardening results in occurrence of cracks in or around the shear bands. The recrystallized, equiaxed and fined grains in shear bands attribute to recovery and recrystallization, grains refinement causes local working hardening as well as decreases of crack tip driving forces. The stresses concentrate in shear bands causing cracks initiation and propagation. Casting defects to be the nucleus of cracks is another failure mode. With the increases of strains, dislocations rearrange forming sub-grains, the low angle grain boundaries (LAGBs) continuously evolved into high angle grain boundaries (HAGBs).
Progressive Damage Analysis of Laminated Composites Using Element Free Galerkin Method
Authors: Hosseini-Toudeshky Hossein , Mazaheri Torei F. , Mohammadi Bijan
Published: August 2010

The aim of the present study is evaluation of the element-free Galerkin method (EFGM) in progressive damage analyses of composite laminates. For this purpose, an orthotropic EFGM formulation is employed which is based on the first-order shear deformation theory (FSDT). In progressive damage analysis, the Hashin’s type failure criteria and their degradation rules are used. The obtained damage results from EFGM are compared with the experimental and FEM results.
Electrical, Thermal and Positron Lifetime Spectroscopy Studies on Multi-Walled Carbon Nanotube Reinforced High Density Polyethylene/Carbon Black Nanocomposites
Authors: Jeevananda T. , Palanna O.G. , Lee Joong Hee , Siddaramaiah  , Ranganathaiah C.
Published: August 2010

The present study investigates the effect of the carboxylated multi-walled carbon nanotube (0~3 wt %) content on the electrical and thermal properties of high density polyethylene/carbon black/carboxylated multi-walled carbon nanotube (HDPE/CB/c-MWNT) hybrid nanocomposites. The room temperature electrical resistivity and positive temperature coefficient (PTC) intensity of the nanocomposites significantly improved with the addition of c-MWNT. However, the heat of fusion decreases as the amount of c-MWNT increases. Further, the microstructural parameters such as the fractional free volume (Fv) and free volume hole size (Vf) of the nanocomposites shows appreciable changes around the percolation threshold. Secondly, the PALS results seem to correlate well with the electrical and thermal properties of the composites.
Viscoelastic Characterization of Fiber-Reinforced Elastomeric Composites at Finite Strain
Authors: Tahaye Abadi Mohammad
Published: August 2010

A viscoelastic model is developed to describe the mechanical response of fiber-reinforced elastomeric composites at large deformation. A continuum approach is used to model the macroscopic mechanical behavior of elastomeric materials reinforced with unidirectional fibers, in which the resin and fibers are regarded as a single homogenized anisotropic material. The anisotropic viscoelastic constitutive model is developed considering transient reversible network theory. An efficient computational algorithm based on micromechanical modeling is proposed to relate the material parameters of constitutive model to the mechanical properties of composite constituents at finite strain. The microstructure is identified by a representative volume element (RVE) and it is subjected to large deformation with considering the conformity of opposite boundaries. The material parameters of the viscoelastic constitutive law are determined based on the response of heterogeneous microstructure which is examined under different loading conditions.
Carbon Nanostructures of Multiple-Branched Fibers Obtained from Alcohol Flames
Authors: Cheng Jin , Zou Xiao Ping , Yang Gang Qiang , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

A set of Y-shaped carbon nanofibers obtained from ethanol flames is reported. The set of Y-shaped carbon nanofibers includes four types of morphologies. No catalyst particles could be found at the junction of Y-shaped carbon nanofibers. The growth mechanism of the multiple Y-junction carbon nanofibers is discussed.
Carbon Nanotubes Grown by Ethanol Catalytic Combustion with an Additive of Thiophene
Authors: Wei Cui Liu , Zou Xiao Ping , Cheng Jin , Yu Zhao Xian , Yang Gang Qiang , Lü Xue Ming , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

Combustion method is a simple method to synthesize carbon nanotubes(CNTs), which employs flames of carbon-contained reactant to synthesize CNTs. It has been proved that combustion method is an effective method to synthesize carbon nanotubes and carbon nanofibers. In this paper, we reported the synthesis of CNTs by using ethanol catalytic combustion with an additive of thiophene, which employed ethanol as carbon source and fuel, nitrate as catalyst precursor, stainless steel as substrate, and thiophene as accelerant. Compared with previous reports on the synthesis of CNTs by ethanol catalytic combustion, great yield of CNTs were obtained with adding thiophene in ethanol. The reproducibility of the synthesis of CNTs in the case of adding thiophene in ethanol was greatly improved.
Controlling Physical Properties of Cementitious Matrixes by Nanomaterials
Authors: Cwirzen Andrzej
Published: August 2010

The majority of concrete used nowadays is based on matrixes formed by hydrating Portland cement. Latest developments in nanosciences introduced a new generation of nano-sized materials possessing often remarkable mechanical and physical properties. These materials can be also used to improve or alter the characteristics of the binder matrixes based on Portland cement. The results showed that mechanical properties such as compressive and flexural strength can be increased by up to 50% by addition of for example 0.23wt% of carbon nanotubes. Carbon nanotubes and carbon nanofibres and/or nanosilica appeared to improve also the frost resistance. Other properties, such as autogenous shrinkage decreased significantly after addition of carbon nanofibres. Nanosilica enabled an immense densification of the hydrated binder matrix, which in turn improved for instance the durability and mechanical properties.
Effects of Concentration of Electrolyte on the Synthesis of PbO Nanostructure by Electrochemical Deposition
Authors: Sun Zhe , Zou Xiao Ping , Cheng Jin , Meng Xiang Min , Wei Cui Liu , Yang Gang Qiang , Lü Xue Ming , Feng Hong Ying , Yang Yuan
Published: August 2010

In this paper, we report a simple method to fabricate lead oxide nanostructure by electrochemical deposition. In our experiment, the electrolyte was lead nitrate aqueous solution containing some drops of concentrated hydrochloric acid. ITO was employed as both cathode and substrate. The controlled current that was supplied by a direct current power supply passed through the electrolyte to deposit the PbO nanostructure on the surface of ITO at room temperature. The morphology of lead oxide was affected by the concentration of electrolyte. So the impact of the electrolyte concentration on the synthesis of PbO nanostructure was discussed. The as-synthesized products were characterized by scanning electron microscopy and X-ray diffraction. Our results indicate that different PbO nanostructure could be formatted with different electrolyte concentration at current densities in the range of 5-10mA/cm2.
Electrochemical Deposition of Lead Oxide Nanorods
Authors: Cheng Jin , Zou Xiao Ping , Meng Xiang Min , Yang Gang Qiang , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

Synthesis of PbO nanorods on an ITO glass by electrochemical deposition was reported. Compared with previous report on the electrochemical deposition of PbO nanorods on stainless steel substrates, massive PbO nanorods were obtained with good reproducibility. The PbO nanorods have a length of several tens of micrometers and a diameter of about 100-200nm. The process for electrochemical deposition of PbO nanorods on ITO glass was investigated.
Estimation of Cure and Thermal Degradation Kinetics of Epoxy/Organoclay Nanocomposite
Authors: Lee Jae Young , Choi Bum Choul , Lee Hong Ki
Published: August 2010

Polymer nanocomposite was synthesized through the intercalation and exfoliation of organoclay in an epoxy matrix. The epoxy matrix was composed of diglycidyl ether of bisphenol A (DGEBA, epoxy base resin), 4,4'-methylene dianiline (MDA, curing agent) and malononitrile (MN, chain extender) and organoclay was prepared by treating the montmorillonite with octadecyltrimethylammonium bromide (ODTMA). The intercalation of the organoclay was estimated by wide angle X-ray diffraction (WAXD) and transmission electron microscope (TEM) analyses. In order to measure the cure rate of DGEBA/MDA (30 phr)/MN (5 phr)/Organoclay (5 phr), differential scanning calorimetry (DSC) analysis were performed at the heating rates of 5, 10, 15 and 20 oC/min, and the data was interpreted by Kissinger equation. Thermal degradation kinetics of the epoxy nanocomposite was also studied by thermogravimetric analysis (TGA). The epoxy sample was decomposed in the TGA furnace at the heating rates of 5, 10, 15 and 20 oC/min with nitrogen atmosphere of 50 ml/min. The TGA data was introduced to the Ozawa equation and the degradation activation energy was calculated according to the degradation ratio. The activation energy for cure kinetics was 43.3 kJ/mol and that for thermal degradation was 171.5 kJ/mol.
Exfoliation of Graphite via Edge-Functionalization with Carboxylic Acid-Terminated Hyperbranched Poly(ether-ketone)s
Authors: Jeon In Yup , Bae Seo Yoon , Baek Jong Beom
Published: August 2010

Because the complete restoration of graphene oxide into graphene is unsuccessful, the “direct” exfoliation of graphite into graphene is still remaining challenge. Here, we report in-situ grafting of carboxylic acid-terminated hyperbranched poly(ether-ketone) (HPEK) onto the edge of graphite to afford “edge-functionalized” HPEK grafted graphite (HPEK-g-graphite). The HPEK plays as a macromolecular wedge to exfoliate graphite. The degree of exfoliation of the resultant HPEK-g-graphite was estimated by wide-angle x-ray diffraction (WAXD), transmission electron microscopy (TEM). Due to the macromolecular wedge effect, the resultant HPEK-g-graphite was dispersible well in common organic solvents. Hence, HPEK-g-graphite could be potentially useful for graphene-based materials.
Gas Sensing Properties of Chemically Synthesized V2O5 Thin Films
Authors: Dhayal Raj A. , Mangalaraj D. , Ponpandian N. , Yi Junsin
Published: August 2010

Nanostructured vanadium pentoxide films have been synthesized by using a sol–gel technology from V2O5 powder and hydrogen peroxide. The V2O5 powder was dissolved in hydrogen peroxide solution, agitated and heated up to 65oC to form gel by the dissociation of the peroxide complexes. The obtained gel was deposited by dip coating technique and dried in air at room temperature. Structural, morphological and compositional analyses were carried out on the prepared samples using X-Ray Diffractometer (XRD), Raman spectrometer and scanning electron microscopy (SEM). The as-prepared films show an amorphous nature, while those annealed at 400oC exhibit orthorhombic structures. The films seem to have grain like structures on annealing which are expected to help the gas sensing properties of the V2O5 films. The annealed films were connected with copper electrodes and used as sensing element. The change in the resistance of the sensing element with respect to the test gas concentration was measured by noting down the resistance at each concentration. Sensitivity of the material linearly increased with different concentrations of ethanol and ammonia. It is clearly seen that the material has more sensing response for ethanol when compared to that of ammonia.
Environmental Effects on Mechanical Properties of Modified and Unmodified Carbon Nanotube/Epoxy Resin Nanoomposites
Authors: Chen Wei Jen , Ho Kung Wei , Li Yi Luen , Shen Ming Yuam , Chiang Chin Lung , Yip Ming Chuen
Published: August 2010

The composites of mechanical and thermal properties of modified and unmodified Carbon nanotube /epoxy resin nanocomposites tested under various circumstances is a major investigation in this study. Identification of functional groups of CNT surface using Fourier transforms infrared spectroscopy (FTIR) was done to male sure if the means of modification adopted in this study is successfully. The tensile and flexural strengths of modified CNT-containing nanocomposites with the amount of modified CNT around 0.75 Phr tested under room temperature circumstance increase 10.96 % and 21.44 % respectively. These two strengths of nanocomposites tested under high temperature circumstance increase 14.55 % and 10.80 % respectively. Additionally, both strengths of nanocomposites tested under high temp.-high humidity circumstance increase 11.65 % and 23.53 % respectively. According to the test results using pyris diamond thermomechanical analyzer (TMA) coefficient decreases 39.81 % with increasing the content of modified CNT and meanwhile glass transition temperature increases 4.15 %. Because of above-mentioned effect, a modified CNs-containing nanocomposite possesses great thermo stability. Overall, No matter what circumstance (high temperature or high temp.-high humidity circumstances) nanocomposites expose to, and no matter whether CNT are modified or not, CNT do significantly enhance mechanical and physical properties of composite.
Growth of Arrayed ZnO Nanorods from Aqueous Solution at 60°C
Authors: Yang Gang Qiang , Zou Xiao Ping , Meng Xiang Min , Teng Gong Qing , Cheng Jin , Su Yi , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

In this paper, zinc oxide nanorods were prepared on many different substrates in the aqueous solution without adding alkali solution at 60°C. A layer of ZnO particles as the seeds for the growth were not needed to be coated on the substrates beforehand. A higher uniform and denser packed array of hexagonal ZnO nanorods forms on the glass substrate than that on the other substrates in our experiments. This technique is applicable for the preparation and patterning of functional ZnO films at low temperature. The growth mechanisms of the as-synthesized ZnO nanorods were also proposed.
Iron-Filled Carbon Nanotube Arrays Obtained by Floating Catalyst Chemical Vapor Deposition
Authors: Cheng Jin , Zou Xiao Ping , Yang Gang Qiang , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

In this paper, we report the synthesis of Fe-filled carbon nanotube arrays by floating catalyst chemical vapor deposition, which employed ferrocene as both catalyst precursor for carbon nanotube growth and the iron source for iron filling. We obtained Fe-filled carbon nanotube arrays perpendicular to the surface of the quartz substrates by floating catalyst chemical vapor deposition. We also conducted controlled experiments at different temperatures. Our results indicated that a higher synthesis temperature is needed for synthesizing Fe-filled carbon nanotube arrays. Magnetic property measurements revealed that the Fe-filled carbon nanotubes exhibited a high average coercivity of about 589.97G.
One-Step Process for the Exfoliation and Surface Modification of Graphene by Electrochemical Method
Authors: Li Peng , Bae Seon Hyeong , Zan Qing Yuan , Kim Nam Hoon , Lee Joong Hee
Published: August 2010

SDBS modified graphene was prepared by electrochemical method using Sodium dodecylbenzenesulfonate (SDBS) as electrolyte and graphite rod as electrode. The anode graphite rod was corroded and deposited at the bottom of the electrolyte solution. The obtained graphene was characterized by Atomic force microscopy (AFM), Raman and Fourier transform infrared spectra (FT-IR). AFM images indicated that most of the layers had the thickness of less than 2 nm, suggesting the fromation of single layer of graphene. The resulting graphene showed very good dispersion stability both in water and in organic solvents (ethanol, acetone).
Preparation and Characterization of an Alginate/Clay Nanocomposite for Optoelectronic Application
Authors: Sultan M. Tipu , Rahman Md. Arifur , Islam Jahid M.M. , Khan Mubarak Ahmad , Rahman Nazia , Alam Noor A. , Hakim A.K.M.A. , Alam M. Mohibul
Published: August 2010

Sodium Alginate/bentonite clay composites of different compositions were prepared by solution casting method. The electrical properties (Conductivity, Dielectric constant) of the composites were investigated by standard methods with Impedance Analyzer. The electrical properties were found to improve with the incorporation of bentonite clay. The thermal, physical and mechanical properties of sodium alginate/bentonite clay composite were investigated by Thermo-Mechanical Analyzer (TMA), X-ray Deffraction (XRD), and Universal Testing Machine respectively. . Tensile Strength (TS) and Elongation at break (Eb) of 2% clay containing composite film were found to be 7.6 MPa and 55% respectively. The XRD demonstrates the enhancing crystallinity of sodium alginate/bentonite clay composite with the increasing clay content. TMA results showed a higher thermal stability in the composite. Water absorption properties of the sodium alginate/clay composite were studied and found to decrease with the increase of clay content. . The inter action between sodium alginate and bentonite clay were studied by Fourier transform infrared spectroscopy (FT-IR). All of the results indicate that the developed composite is promising for use in a wide variety of optoelectronic applications.
Preparation of SiC/SiO2 Core-Shell Coaxial Nanostructure
Authors: Wang Yu Lian , Zhu Guang , Zou Xiao Ping , Cheng Jin
Published: August 2010

A simple direct synthesis method was used to synthesis SiC/SiO2 core–shell coaxial nanocables by thermal evaporation of the mixture powders of silicon monoxide and active carbon at 1300°C and condensation on Si substrate without assistance of any catalyst. The SiC core typically has diameters of 10-40 nm and is covered by a uniform layer of 2-10nm thick amorphous SiO2. A double vapor–solid growth process is proposed for the formation of this novel structures based on detailed structural characterizations. The cable nanostructures may find applications as building blocks in nanomechanical or nanoelectronic devices.
Properties and Rapid Consolidation of Nanostructured Fe3Al Compound by High Frequency Induction Heating
Authors: Shon In Jin , Kim Tae Wan , Doh Jung Mann , Yoon Jin Kook , Na Kwon Il , Ko In Yong
Published: August 2010

A dense nanostuctured Fe3Al was consolidated by high frequency induction heated sintering method within 2 minutes from mechanically synthesized powders of Fe3Al and milled powders of 3Fe+Al. The consolidation was accomplished under the combined effects of a induced current and mechanical pressure. The grain size, sintering behavior and hardness of Fe3Al sintered from horizontally milled Fe+Al powders and high energy ball milled Fe3Al powder were compared.
Keywords: Combustion synthesis; Nanomaterials; Mechanical properties; Rapid sintering
Fabrication and Properties of 1-3-2 Piezoelectric Composites
Authors: Huang Shi Feng , Xu Dong Yu , Chang Jun , Liu Ya Mei , Cheng Xin
Published: August 2010

In this paper, the 1-3-2 piezoelectric composites were fabricated by the cut-filling technique using P(MN)ZT piezoelectric ceramic as functional materials and polymer as matrix. The effects of ceramic volume fraction on the electrical properties of the composites were studied. The results indicate that as the ceramic volume fraction increases, the piezoelectric stain factor d33 increases evidently, while the piezoelectric voltage factor g33 decreases. Besides, the planar electromechanical coupling factor Kp and mechanical quality factor Qm of the composite are also less than those of the pure ceramic, while the thickness electromechanical coupling factor Kt is larger than that of the ceramic.
Sintering and Mechanical Properties of Dense Hydroxyapatite Nanocomposites
Authors: Monthien Chanoknan , Silikulrat Kanjana , Rujijanagul Gobwute , Tunkasiri Tawee , Punyanitya Sittiporn , Raksujarit Anirut
Published: August 2010

During recent years, there have been efforts in developing nanocrystalline bioceramics, to enhance their mechanical and biological properties for use in hard tissue engineering applications. In this work, we study the effects of some sintering additive nanopowders dopants on the properties of the sintered HA structures. Calculated quantities of silica nanopowders are incorporate as dopants into dried HA nanopowder. The mixing powders are uniaxially compacted and then sintered at 1200°C by rate-controlled sintering method in air. Compositional, microstructural, morphological and mechanical characterizations are carried out on sintered HA samples.
Synthesis and Controlled Growth of ZnO Nanorods Based Hybrid Device Structure by Aqueous Chemical Method
Authors: Suresh Kumar P. , Sundaramurthy J. , Mangalaraj D. , Rajarathnam D. , Srinivasan M.P.
Published: August 2010

In the present work, vertical ZnO nanorods (NRs) were grown onto ITO substrates by a simple two step chemical process at relatively low temperature by using successive ionic layer absorption and reaction method (SILAR) and chemical bath deposition (CBD) method. The investigated on n- ZnO/ p-Polythiophene heterojunction device have been fabricated with ZnO nanorods. Structural analysis reveals that the grown ZnO NRs exhibit (002) reflection with higher intensity, indicating that the ZnO NRs grown in c-axis orientation. FESEM image shows the surface morphology of grown ZnO nanorods was of hexagonal wurtzite structure whose diameter varies from 200 nm to 1μm. Room temperature Photoluminescence exhibited strong UV emission at ∼386 nm and a negligible green band confirms the presence of very low concentration of oxygen vacancies in the well-aligned ZnO nanorods. The current–voltage (I –V) characteristics of the heterojunctions show good rectifying diode characteristics. These results indicate that hybrid device fabricated from solution process is a promising approach for future light-emitting diodes (LEDs) devices.
Synthesis of Well-Aligned Multi-Walled Carbon Nanotubes by Floating Catalyst Chemical Vapor Deposition
Authors: Cheng Jin , Zou Xiao Ping , Yang Gang Qiang , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

Well-aligned multi-walled carbon nanotube (MWNT) arrays were grown by floating catalyst chemical vapor deposition (CVD) on quartz substrate. The MWNTs in arrays had a uniform diameter of 30-50nm and high degree of graphitization. We find that catalyst nanoparticles with different sizes can be separated and deposit at different position by carrier gas flow under gravity effect in floating catalyst CVD. It is one of the main reasons that lead to the growth of well-aligned MWNTs.
ZnO Nanorod Arrays and Nanowires by Hydrothermal Growth
Authors: Su Yi , Zou Xiao Ping , Meng Xiang Min , Teng Gong Qing , Yang Gang Qiang , Lü Xue Ming
Published: August 2010

We are reporting here on an inexpensive and facile fabrication method for ZnO nanorod arrays by hydrothermal growth at low temperature (90°C). In our experiment, ZnO nanostructures were grown on glass substrate using an equimolar (0.1M) aqueous solution of Zn(NO3)2•6H2O (zinc nitrate hexahydrate) and C6H12N4 (HMTA) as precursors solution, and using ammonia solution to controlling the pH levels. It enable easily obtained arrayed ZnO nanorods on substrate, and nanowires which grown on nanorod arrays were identified after about 1 month in the air. The growth process of nanorods and the formation mechanism of nanowires were investigated.
Thermal Insulation Test of RCCW with Inner Insulating Layer
Authors: Zhao Shun Bo , Zhao Shan , Yang Su , Ma Xiao Lu
Published: August 2010

To improve the durability of external thermal insulation plate on walls, the new reinforced concrete composite wall(RCCW) with inner insulating layer of polystyrene panel was developed. The paper introduces the thermal insulation tests of the RCCWs by the protection chest method, and studies the method for eliminating the effect of heat-bridge on the test results of conduct heat coefficient of the RCCW. The results show that the test value of conduct heat coefficient of the RCCW was obviously affected by the heat-bridge in specimen caused by the connected concrete such as support and concrete cover around the polystyrene panel, the practical value can be obtained by mean of taking off the percent of heat-bridge effect.
Ultrasonic Propagation Imaging for Wind Turbine Blade Quality Evaluation
Authors: Lee Jung Ryul , Shin Hye Jin , Chia Chen Ciang , Jeong Hyo Mi , Yoon Dong-Jin
Published: August 2010

Soundness of wind turbine blade plays paramount role in supplying cheap and reliable wind energy. To ensure that blades are sound and free from inherent manufacturing defects, easy and reliable quality evaluation before delivering blades for installation is crucial. We propose an ultrasonic amplitude imaging method based on Ultrasonic Propagation Imaging (UPI) system for this purpose. The system utilizes a scanning Q-switched continuous wave laser as ultrasonic wave generator. Various acousto-ultrasonic sensors, either contact or non-contact type, could be adopted as ultrasonic receiver. The system was tested on a blade section made of glass fiber reinforced plastic sandwiched with balsa wood. The leading edge of the specimen with a kissing disbond was inspected. A PZT-based sensor attached temporarily on the outer surface of a blade was used for ultrasonic reception to demonstrate that this imaging method is applicable even for the blades without integrated sensor. The amplitude map clearly showed the disbond defect with the kissing features. The location, shape, and size of the defect evaluated from the result agree excellently with the actual defect. The result proved that the proposed method works well for the quality evaluation of wind turbine blades. Inheriting the advantages of UPI technology, i.e. focusing-free characteristics, acceptance of large laser incident angle up to 60°, and rapid scanning without needing an expensive scan gantry, this system is suitable for automatic quality evaluation of blades with different geometry. On top of that, this system does not require any reference data, making it a flexible quality evaluation system suitable for different methods of blade production flow.
Aggregation, Isomerization and Thermo-Optic Property of Azobenzene Polyelectrolyte
Authors: Qiu Feng Xian , Yang Dong Ya , Zhang Qing , Cao Guo Rong
Published: August 2010

A novel azobenzene polyelectrolyte (ABAPE) was synthesized based on chromophore 4-(4’-nitrophenylazo) naphthol (NPAN), epoxychloropropane and α-methacrylic acid. The ABAPE was characterized by FT-IR and UV-vis spectroscopy. The aggregation behaviors of ABAPE were investigated based on different pH values by the UV-vis spectroscopy. The isomerization behavior of the ABAPE in DMAC solution was studied by 256 nm UV irradiation light. Attenuated total reflection (ATR) method was adopted and carried out the measurement of refractive index of the thin film. The thermo-optic coefficient (dn/dT) was -2.9228×10-4°C-1 and was bigger than inorganic materials such as silica glass, zinc silicate glass, borosilicate glass and the organic materials of polystyrene and PMMA. These results showed that the polyelectrolyte could be used to carry out optical storage and thermo-optic switch.
Aircraft Wing Inspection Based on Anomalous Wave Propagation Imaging
Authors: Lee Jung Ryul , Chia Chen Ciang , Shin Hye Jin , Kim Jong Heon , Park Chan Yik
Published: August 2010

Non-destructive evaluation (NDE) and structural health management (SHM) with the ability to evaluate the severity of a damage are important to ensure the reliability of a structure. We propose a local non-destructive evaluation (NDE) system based on Anomalous Wave Propagation Imaging (AWPI) method. When possible damage is flagged during the lifecycle of the structure, the proposed system will be launched for automatic damage evaluation. This technology was demonstrated on a CFRP skin-spar-stringers wingbox integrated with an AE sensor. 17 mm diameter impact damage was made between the stringers using hammer strike from outer surface of the skin. Based on the impact location determined by other global structural health monitoring system, the AWPI automatically inspects an area 400×400 mm2 with the impacted location enclosed. Anomalous Wave Propagation Movie (AWPM) was generated as inspection result. As contrast to its predecessor, the AWPM shows only the damage induced ultrasonic wave (anomalous wave), making the damage detection an intuitive decision making process. Precise damage localization was performed by identifying the location of area with anomalous wave propagation in the AWPM. Besides, the size of the area with anomalous wave agreed well with the size of impact damage, which demonstrated that damage size quantification is possible using the proposed system. Being sensitive only to anomalous wave, it is expected that this NDE system is exceptionally suitable not only for aircraft structures such as wingbox with stiffeners, but also for other complex engineering structures.
Determination of Vibration Source Locations in Laminated Composite Plates Using Lamb Wave Analysis
Authors: Du Chao , Ni Qing Qing , Natsuki Toshiaki
Published: August 2010

Signals propagate on plate-like structures as ultrasonic guided waves, and analysis of Lamb waves has been widely used for on-line monitoring. In this study, the wave velocities of symmetric and anti-symmetric modes in various directions of propagation were investigated. Since the wave velocities of these two modes are different, it is possible to compute the difference in their arrival times when these waves propagated the distance from the vibration source to sensor. This paper presents an evaluation formulation of wave velocity and describes a generalized algorithm for locating a vibration source on a thin, laminated plate. With the different velocities of two modes based on Lamb wave dispersion, the method uses two sensors to locate the source on a semi-infinite interval of a plate. The experimental procedure supporting this method employs pencil lead breaks to simulate vibration sources on quasi-isotropic and unidirectional laminated plates. The transient signals generated in this way are transformed using a wavelet transform. The vibration source locations are then detected by utilizing the distinct wave velocities and arrival times of the symmetric and anti-symmetric wave modes. The method is an effective technique for identifying impact locations on plate-like structures.
Development of Sensor Integrated Composite Wing Structure
Authors: Choi Mi Jin , Kim Jin Seong , Kim Young Kyu , Kim Jong Hoon , Choi Ko Woon , Park Chan Yik , Kim Jong Heon
Published: August 2010

Demands for improved aerial vehicle performance have led to the increasing use of composite materials. However, the mechanical behavior and failure modes of composites are not characterized as well as metals, and damages may be more difficult to detect. To overcome this, there is a demand to develop a structural health monitoring (SHM) system for composite aerial vehicles. This paper presents the development of sensor integrated composite wing structure, which is an essential part of SHM system. The composite wing structure was manufactured using an autoclave process, and Fiber Bragg Grating (FBG) optical sensor and piezoelectric (PZT) sensor were installed. The optimal number and location of each sensor system are determined based on the experimental results and Finite Element Analysis (FEA). Installation procedures for FBG and PZT sensor system are developed and validated using tension-tension fatigue tests over 106 cycles.
Ultrasonic Inspection of Fiber Reinforced Cement Based Composites after their Exposure to Fire Conditions
Authors: Pandermarakis Zacharias G. , Sotiropoulou Anastasia B. , Nikoloutsopoulos Nikolaos D.
Published: August 2010

Fiber reinforced cement based composites was exposed to high temperature conditions for up to 900oC and up to 2 hours and then they checked about their mechanical response and their convenience for ultrasonic wave transmission. Glass and polypropylene chopped fiber composites showed similar results. For low temperatures of exposure up to 300oC only a small variation of strength is appeared and a slight reduction of ultrasonic wave transmission. This is due to a corresponding water evaporation of wet not even hardened paste that is enclosed in small pores of cement composites. At the next stage and for temperature up to 800oC a steep drop of the mechanical strength of cement based composites is appeared. This reduction is accompanied by a corresponding decrease of ultrasonic wave velocity in the exposed specimens. The characteristic appearance of this stage is due to the dehydration process of calcium hydroxide that takes place at the temperature of about 400oC. At a third stage that starts from 800oC a total destruction of composite is appeared due to the decomposition of carbonate aggregates at 900oC. Typical sigmoidal curves were appeared according to temperature exposure, with that of ultrasonic wave transmission to be less steep, reaching values of 30% for an exposure of 900oC for 2 hours, whereas the mechanical strength for this level of exposure was less that 10% of the unexposed one.
Degradation of Volatile Acetone by a Photocatalytic Reactor with TiO2 Coated Sieve
Authors: Chang Chen Yu , Lee Yao Chuan , Lin Ching Hsing , Lee Jyh-Wei , Chang Yu Jie , Chen Jian Huan
Published: August 2010

The TiO2 thin films were coated on the 100 meshes stainless steel 304 (SS304) sieves by using the sol-gel method followed by a thermal treatment at 200oC. The prepared TiO2-coated sieves were then employed to setup a photocatalytic reactor for evaluating their abilities on the degradation of VOCs (volatile organic compounds). The UV lamp was enveloped with a cylinder TiO2-coated sieve and located in the center of the reactor. A VOCs diffusing tube was applied to yield acetone under water bath. The yielded gaseous acetone was enforced to pass through the TiO2-coated sieves and reacted by photocatalytic reaction. Both the inflow gas and off-gas were monitored by a PID (photoionization detector) sensor for calculating the treat efficiencies under various conditions. The results showed that the amorphous structure was observed on the TiO2 films after sol-gel method, whereas the crystalline anatase phase was found after annealing at 200oC. The SEM images showed that the surface morphology of TiO2 coated SS304 sieves was very similar to that of uncoated sieves, demonstrating a good uniformity and thin thickness of the sol-gel coating method derived in this work. It was observed that most volatile acetone (almost 100%) was removed after treated with the designed photocatalytic reactor under a high fed flow rate (0.5- 2.0 l/min). As compared with the control experiments (UV OFF test), the adequate photocatalytic abilities of this developed TiO2 coated sieves were demonstrated. With the advantages of high contacting area with VOCs, low headloss, durable substrate and easy maintenance, the TiO2-coated sieves possessed a high potential for applying on the photocatalytic degradation of indoor air pollutants.
Formation Mechanism and Properties of Polyvinylidene Fluoride (PVDF)/Nano-Silica Hybrid Membranes
Authors: Shen Hui Ling , Liao Hua , Xiao Chang Fa
Published: August 2010

By means of the wet phase inversion process, the PVDF/silica (SiO2) hybrid membranes with different content of nano-silica (nano-SiO2) were prepared. It was investigated that the pure water flux and retention based on egg albumin solution for different PVDF hybrid membrane samples. The pure water flux and porosity of PVDF/SiO2 hybrid membranes are enhanced simultaneously with increasing SiO2 content in PVDF composite system. When SiO2 content is around 7.5%, the phase separation rate of casting solution increases to peak value, meanwhile, the retention of hybrid membrane achieves the best effect. The SEM micrographs show that the quantity of finger-like pores of PVDF/SiO2 hybrid membranes decreases and the micropores becomes fine compared to PVDF membrane. The results of DSC indicate that there are almost no effects on the melting point, but enhancement the fusion enthalpy and the crystallinity of PVDF along with increasing the SiO2 content.