bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Castor Oil Polyurethane Reinforced with Lignin and Cellulose from Sugarcane Straw
Authors: Câmara Mileo Patrícia , De Oliveira Matheus F. , Luz Sandra M. , Rocha George J.M. , Gonçalves Adilson Roberto
Published: August 2010

The search for materials from renewable sources such as vegetable oil-based polymers, polyurethane based on castor oil represents a promising alternative in researches. Using castor oil polyurethane as matrix for composites reinforced with lignin and cellulose from sugarcane straw is in tune with economical and environmental interests. The objective of this work was the evaluation of the changes on the structure and thermal behavior of castor oil polyurethane composites reinforced with lignin and cellulose from sugarcane straw. The cellulose and lignin were extracted from the straw by acid hydrolysis and then they were milled. For the production of the polyurethane, the mass reason between polyol (castor oil) and diisocyanate was 1.5:1.0. Reinforcement of the matrix was done changing the concentration of cellulose and lignin. SEM micrographs of fractured surfaces of the obtained composites and thermal analysis (TGA) were done. No lignin could be seen in SEM micrographs, what suggests a blend material behavior. The addition of cellulose fibers (30%) and lignin (40%) to the polyurethane matrix has caused an increase of the stiffness in the resulting composite when compared with the pure matrix. Above these rates, stiffness decreases. The presence of lignin or cellulose fibers in polyurethane matrix seems to increase mechanical properties of the composite, and also introduce better thermal stability than the pure matrix. Its presence might also bring other significant synergetic properties to the final composite, what has currently been studied. At the same time, the blend behavior of Polyurethane-Lignin composites has been investigated.
Experimental Evaluation for Mechanical Property of Unidirectional Banana Reinforced Polyester Composites
Authors: Gohil Piyush P. , Shaikh A.A.
Published: August 2010

Development of composite materials requires reinforcement and matrix in which fiber is finest suitable material for reinforcement which improves properties of materials. The use of high strength fiber leads to birth of advanced composites, which are mainly used, for high strength application or aerospace application. However, the use of medium strength and low strength fiber available in nature are also having enough potential for other application where high strength are not critical but it can provide a feasible range of alternative materials to suitable conventional material. Several billion tons of fillers and reinforcements are used annually in the plastics industry, and there is a huge potential market for recyclable, energy efficient and more environmentally friendly composite materials. The present work examines the different types of natural fiber available for the development potential composites. The attempts are already made for jute, flax and sisal natural fibers provides data from literature but there is lack of experimental data availability for unidirectional natural fiber composite like cotton, pineapple, banana fiber reinforced unidirectional composite. It is decided to carry out the systematic experimental study for the effect of volume fraction of reinforcement on longitudinal strength as well as elastic modulus using developed mould-punch set up and testing aids. The testing is carried out as per ASTM D3039/3039M-08. Specimen failure inspection was carried out through Scanning Electron Microscope (Model: Hitachi S-3400N). The comparative assessment of obtained experimental results with predictive models forms an equally important constituent of present work.
Properties of Esterificated Wood with Oxalic Acid and Cetyl Alcohol
Authors: Wang Xiang Jun , Zhang Ming Hui , Wang Xi Ming
Published: August 2010

Two-step for wood esterification with oxalic acid and cetyl alcohol is developed in this study. The esterified wood powder was investigated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results show that ester groups substituted parts of the original alcoholic hydroxyl groups, and crystallization occurred during the modification. In addition, surface wettability, moisture adsorption and water absorption tests for wood specimen have showed that the modification improves the moisture and water resistance.
Fluorescence Properties of Pr3+ Doped Calcium Fluoroborate Glasses
Authors: Suresh Kumar J. , Pavani K. , Sasikala T. , Jamalaiah B.C. , Jayasimhadri M. , Jang Ki Wan , Rama Moorthy L.
Published: August 2010

Calcium fluoroborate glasses doped with trivalent praseodymium ions have been prepared using melt quenching technique with the molar composition (42-x) B2O3 + 20 CaF2 + 15 CaO + 15 BaO + 8 Al2O3 + x PrF3 (x = 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0). Absorption, fluorescence and lifetime spectra were recorded for the title glasses. Judd-Ofelt intensity parameters Ωt (t = 2, 4 and 6) have been determined for the measured oscillator strengths of the absorption bands by including and excluding the 3H4 → 3P2 hypersensitive transition. From the intensity parameters spontaneous emission probabilities (AR), excited state radiative lifetimes (τR) and branching ratios (βR) were calculated. Fluorescence quenching is observed in all the peaks and is explained by energy transfer mechanisms. Using the fluorescence spectra stimulated emission cross section (σe) for all emission transitions have been estimated. Energy transfer processes were also explained to emphasize the quenching of fluorescence intensity of certain emission transition. Based on the results, the utility of Pr3+ doped calcium fluoroborate glasses as laser active materials as well as wave guides in the visible region is discussed.
Lead Oxide Plate Precipitates from Lead Nitrate Solution
Authors: Yang Gang Qiang , Zou Xiao Ping , Meng Xiang Min , Cheng Jin , Lü Xue Ming , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan
Published: August 2010

In this paper, a simple and controllable method to fabricate - and -PbO is reported. Lead nitrate as precursor was dissolved in 50ml distilled water, and was heated to 80oC. Sodium chloride was added into the lead nitrate aqueous solution. During the process, -PbO deposition will be obtained when we add lead nitrate solutions with KOH pellets without chloride anion. When we add lead nitrate solutions with KOH pellets with a little chloride anion, there will produce -PbO deposition. Our results indicate that the concentration of chloride anion and temperature of reaction solution affects the crystal morphologies and modifications of lead monoxide plate precipitates from lead nitrate solution and we can selectively and controllably produce - or -PbO by this way.
Study on Synthesis and Performances of Casein Resin Grafting Modified by Caprolactam/Acrylic Esters/Vinyl Acetate/Organic Silicone
Authors: Ma Jian Zhong , Xu Qun Na , Gao Dang Ge
Published: August 2010

Casein was grafting modified by caprolactam, acrylic esters, vinyl acetate and organic silicon,in order to improve the film-forming defects of casein such as hard, brittle and excessive moisture absorption performance,etc.In this paper, emulsion properties and film-forming performances were taken as the main indexes to inspect the influence of the type and dosage of organic silicon on the final modified casein resin ,results showed that modified casein could be granted more superior water resistance, smoothness and softness with introducing a relative more amount of A-151. Meanwhile, the structure of modified casein were characterized by FT-IR and TEM, results indicated that: grafting copolymerization between casein and grafted monomers did happen actually.
Mechanical Properties of Epoxy Clay Nanocomposites
Authors: Ghafarloo Sahar , Kokabi Mehrdad
Published: August 2010

Achievement of exfoliated structure of polymer/ Clay nanocomposites is of particular interest for the improvement of mechanical properties. In this work, the morphology and mechanical properties of epoxy/ clay nanocomposites has been investigated. Diglycidyl ether of bis-phenol A (DGEBA) epoxy resin (EPON828) and Jeffamine D400 curing agent was used. To obtain perfect dispersion, nanoclay (Cloisite 30B) was sonicated in acetone. The mixture was then mixed with polymer. Afterwards, the curing process was performed by addition of curing agent and degassing. Disappearing of peaks in X-Ray diffraction patterns of nanocomposites containing less than 5wt% nanoclay, is a good evidence of perfect dispersion of layered silicates in matrix, i.e. formation of exfoliated morphology. Based on tensile test results, it is deduced that as the amount of nanoclay increases, the elastic modulus and elongation at break of the nanocomposites containing 1wt% and 5wt% nanoclay increases by 12% and 31%, respectively. Therefore, obtaining perfect dispersion of layered silicates in epoxy matrix and exfoliated morphology, results in better mechanical properties of the nanocomposites.
Preparation and Evaulation of Degradable Poly(lactic acid) Composite Dressings
Authors: Lou Ching Wen , Lu Chao Tsang , Wen Shih Peng , Lin Ching Wen , Chao Chieh Yu , Lin Jia Horng
Published: August 2010

Chitosan and sodium alginate are two prominent biomaterials because they have some unique properties such as good biocompatible and biodegradable. In this study, sodium alginate was as swelling and moisture retention layer; Chitosan was antibacterial layer.Polylactic acid (PLA) blended in different weight ratios with low melting point polylactic acid (LMPLA) to fabricate nonwoven fabric which reinforced by needle punching and hot pressing. Afterward, chitosan/ sodium alginate compound solution were treated by UV light in order to form cross-linking. Then chitosan/ sodium alginate compound solution coated on the PLA nonwoven fabric to make PLA composite dressings. The mechanical properties of chitosan/ sodium alginate membrane and dressing were measured. The optimum parameters of chitosan/sodium alginate composite membrane was treated by UV light for five minutes and the volume ratio of chitosan (3 wt %) and sodium alginate (1 wt %) solution was 8:2. After we coated chitosan/sodium alginate solution on PLA nonwoven fabric, the Tensile strength, and tear strength were upgraded by 80 % and 98 %; its air permeability and flexibility length, however, dropped by 18 % and 60 %, respectively.
Preparation of Poly(diallydimethyl ammonium chloride) (PDDA)/Au Nanocomposite Film by In Situ Electrochemical Reduction and its Electrocatalytic Properties
Authors: Shi Hong Wei , Zhang Li , Wang Cong , Zhang Ke Ying
Published: August 2010

Nanocomposite films containing Au nanoparticles were fabricated by alternating adsorption of poly(diallydimethyl ammonium chloride) (PDDA) and HAuCl4 using layer-by-layer self-assembly technique and subsequent in situ electrochemical reduction of the AuCl4- ions. The composition and properties of the composite films were characterized by ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV).The UV-vis characteristic absorbances of PDDA and Au increase almost linearly with the number of bilayers, which suggests a progressive deposition with almost an equal amount of the PDDA and Au in each cycle. X-ray photoelectron spectroscopy further confirms the presence of the main components (such as PDDA and Au) of the nanocomposite films. Furthermore, the nanocomposite films also exhibit good electrocatalytic activity for the oxidation of ascorbic acid (AA), which may be used in electrochemical biosensors.
Simultaneous Synthesis and Densification of Nanostructured NbSi2-SiC-Si3N4 by Rapid Sintering
Authors: Shon In Jin , Kang Hyun Su , Bae Soo Kyung , Ko In Yong
Published: August 2010

A dense nanostructured 5NbSi2-SiC-Si3N4 composite was synthesized by the high-frequency induction-heated combustion synthesis (HFIHCS) method within 1 minute in one step from mechanically activated powders of 4NbN, NbC and 14Si. A highly dense 5NbSi2-SiC-Si3N4 composite with relative density of up to 98% was produced under the simultaneous application of a pressure of 80 MPa and the induced current. The average grain size and mechanical properties (hardness and fracture toughness) of the composite were investigated.
Studies on Preparation and Properties of Novel Gel Polymer Electrolyte
Authors: Wang Cun Guo , Yuan Wei Na , Lu Nai Qun
Published: August 2010

The cheaper plant materials such as wheat straws and corn stalks, which contain a lot of celluloses, were used to synthesize the new GPE by graft copolymerization with acrylic acid (AA). A kind of thinner film was prepared by coating the mixture of above precursor with polyvinyl alcohol (PVA). The new polymer film was expected to have larger uptake of standard liquid electrolyte. Therefore, its ionic conductivity could reach to 6.7×10-3 S•cm-1, which was near to the conductivity of liquid electrolyte (~10-3 S•cm-1). So the lithium batteries containing the new GPE could have better charge-discharging efficiency with larger current density. The new GPE was also expected to be degradable as it was made of plant stem materials.
Study on the Crystallization and Morphology of HDPE-g-GMA Modified PA66/UHMWPE Blends
Authors: Zhao Zi Nian , Zhang Wen Hua , Lei Gang Qiang
Published: August 2010

By means of melt compounding method, the Glycidyl methacrylate (GMA) grafted HDPE modified Polyamide 66 (PA66) with ultra high molecular weight polyethylene (UHMWPE) blends were prepared via the co-rotating twin screw extruder．The effects of different UHMWPE/HDPE contents on properties of PA66/UHMWPE blends were investigated．Meanwhile, the mechanical properties such as tensile and impact strength etc. were investigated. By using the differential scanning calorimetry (DSC) and scanning electron microscope (SEM), the crystalline and morphology of PA66/UHMWPE blends were analyzed. The results show that UHMWPE toughened PA66 samples exhibit significantly enhanced impact strength and elongation at break comparison with natural PA66. The samples of PA66 with 30% of UHMWPE/HDPE (mass ratio 3/7) blends show impact strength about 2 times and elongation at yield 7 times more than those of natural PA66．The behavior of HDPE-g-GMA shows an effective compatibilizer for PA66/UHMWPE blends, when the mass ratio of PA66/(UHMWPE/HDPE) at 70:30, the blend indicates the best comprehensive property. The investigation on crystallization and morphology of PA66 and their blends show that the behaviors of melting about the two components are independent either PA66 or UHMWPE/HDPE. There are independent melting behaviors, meanwhile, interacted each other between PA66 and UHMWPE. Due to the good compatibility which HDPE-g-GMA contributed, the homogenous PA66/UHMWPE blends could be achieved. The photographs of SEM analysis indicate that the interface action of PA66 and polyethylene is enhanced by compatibilizer HDPE-g-GMA.
Study on the Preparation and Properties of EVA-G-PU/OMMT Nanocomposites
Authors: Zhang Yu Qing , He Yu Xin , Zhang Li , Li Jun Xian
Published: August 2010

A new type of EVA-g-PU/OMMT nanocomposites was synthesized through the method of chemical modification and melt intercalation. FTIR testing showed that the PU prepolymer was grafted on EVA main chains successfully. The structures of EVA-g-PU/OMMT nanocomposites were characterized by X-ray diffraction (XRD) and by high-resolution transmission electron microscopy (HRTEM). The enhanced storage modulus of EVA-g-PU/OMMT nanocomposites was characterized by dynamic mechanical analysis (DMA). The thermal stabilities of EVA/clay nanocomposites were also studied by thermal gravimetric analysis (TGA). Mechanical testing showed that the tensile strength and tear strength of EVA-g-PU/OMMT nanocomposites were far superior to pure EVA.
Synthesis of Magnetic TiO2 Nanoparticles as Bactericidal Photocatalyst
Authors: Chin Ching Ju Monica , Chang Yu Jie , Weng Guo Jie , Shen Chia Yu
Published: August 2010

The magnetic photocatalysts can provide both a high specific surface area and an alternative for recovering used catalyst from treated water by the application of a magnetic field. In this study, the Fe3O4 nanoparticles were synthesized by co-precipitation. After chemical co-precipitation of ferric and ferrous solution under alkaline condition, the suspension of magnetite nanoparticles were then mixed with TEOT (Titanium (Ⅳ) ethoxide) for sol-gel coating. The separated MPCs (magnetic photocatalyst nanoparticle) were then dried and calcined in 400oC. Magnetic properties of MPCs were identified by superconducting quantum interference device magnetometer (SQUID). The bactericidal ability of synthesized MPCs was evaluated by counting the residual numbers of E. coli after irradiation under a light intensity of 1.0 mW/cm2 at 365 nm. The results show that the MPCs were both anatase and had good crystallinity with clear peaks and insignificant noises after calcination. The SQUID test also reveals that calcination only affects the magnetic susceptibility of the MPC nanoparticles slightly (< 8%). The bactericidal ability of the synthesized MPCs was compared with the commercial TiO2 nanoparticle DegussaTM P25; P25 provided a faster inactivation rate for E. coli in water than MPCs did at the same dosage. The calculated photocatalytic bactericidal rate by P25 is about 3.6 times faster than that by MPCs synthesized in this work. However, the bactericidal rate of magnetic TiO2 synthesized in this work was 5 times than that of other MPCs in the literature. The particles size and surface area of MPCs from this work were about 135 nm and 210 m2/g, respectively. The MPCs from this work have much smaller size and larger surface area; hence there are more active sites for bactericidal reaction.
Fabrication and Characterization of RF Plasma Polymerized Thin Films from 3,7-Dimethyl-1,6-octadien-3-ol for Electronic and Biomaterial Applications
Authors: Bazaka Kateryna , Jacob Mohan V. , Shanks Robert A.
Published: August 2010

Poly(linalool) thin films were fabricated using RF plasma polymerisation. All films were found to be smooth, defect-free surfaces with average roughness of 0.44 nm. The FTIR analysis of the polymer showed a notable reduction in –OH moiety and complete dissociation of C=C unsaturation compared to the monomer, and presence of a ketone band absent from the spectrum of the monomer. Poly(linalool) were characterised by chain branching and a large quantity of short polymer chains. Films were optically transparent, with refractive index and extinction coefficient of 1.55 and 0.001 (at 500 nm) respectively, indicating a potential application as an encapsulating (protective) coating for circuit boards. The optical band gap was calculated to be 2.82 eV, which is in the semiconducting energy gap region.
Mechanical, Thermal and Morphological Behaviors of Coconut Shell Powder Filled Pu/Ps Biocomposites
Authors: Roopa S. , Siddaramaiah
Published: August 2010

Castor oil based polyurethane (PU) interpenetrating polymer network (IPN) has been prepared by using castor oil, toluene diisocyanate and styrene monomer. The coconut shell powder (CSP) particulate filler with different weight ratios viz., 0, 5, 10, 20 and 30 wt % were incorporated into polyurethane/polystyrene (PU/PS, 90/10) IPN. The effects of CSP particulate filler loading on the physico - mechanical and thermal properties of PU/PS IPN biocomposites have been studied. From the tensile behavior, it was noticed that a significant improvement in tensile strength and tensile modulus with increase in CSP filler content. It was found that the degradation of all composites takes place in two steps. Degradation kinetic parameters were obtained for the composites using Broido (BR), Coats–Redfern (CR) and Horowitz-Metzger methods (HM). The damping property reduced after the incorporation of CSP filler. Morphology of the cryo-fractured composites was studied using scanning electron microscopic technique (SEM).
Damping Capacity of SiCp/AZ61 Composites
Authors: Yan Hong , Xin Huang , Hu Qang
Published: August 2010

Magnesium matrix composites SiCp/ AZ61 reinforced with SiC particulates was fabricated by stirring-melt casting technique. The damping properties of the composites have been studied with dynamic mechanical thermal analysis and micro-structural observation. The results show that matrix grains introduced SiC particulates were refined obviously at room temperature and the properties of SiCp/ AZ61 composites were improved comparison to AZ61 alloy. Meanwhile, the improvement of damping properties can be explained by G-L dislocation pinning theory. The damping characterization is explained with the increasing of quantities of the grain-boundaries for the introducing of SiC particles and the ease of interface slipping in temperature.
Structure-Property Relationship of Castor Oil Based Chain Extended Polyurethane/Starch Biocomposites
Authors: Siddaramaiah  , Gowda Manjula Koregala Sidde , Lee Joong Hee
Published: August 2010

Polyurethane (PU)/starch biocomposites have been prepared with different weight fractions of starch (viz., from 0 to 40 wt %). The fabricated PU/starch composites were characterized by mechanical properties and thermal (DSC and TGA) behaviors. Microcrystalline parameters were calculated using X-ray profile. Water uptake and its effect on mechanical properties have been evaluated.
Curing Kinetics and Rheology of Diglycidyiether of Bisphenol-A Modified by Poly(ethylene glycol) Flexible Chains
Authors: Yao Da Hu , Sun Kyung Bok , Li Peng , Lee Joong Hee
Published: August 2010

The curing reaction of the system bisphenol-A glycidol ether epoxy resin modified by poly (ethylene glycol) (PEO) and flexible amine (D-230) as curing agent has been studied by means of differential scanning calorimetry (DSC) and thermal scanning rheometry. The curing kinetic parameters have been calculated from the non-thermal DSC curve. The kinetic analysis suggests that the two-parameter autocatalytic model is more appropriate to describe the kinetics of the curing reaction of the system. Increasing the PU content leads to an increase in the heat of curing and has a little effect on the kinetic parameters apparent activation energy (Ea), pre-exponential factor (A), and order of the reaction (m and n). The rheological properties were measured by isothermal curing evolution. Introduction of PEO flexible chains delayed the polymerization. It has been confirmed that the introduction of PEO chains in the structure of the epoxy resin increases the mobility of the molecular segment of the epoxy networks and results in the decrease in glass transition temperature.
Evaluation on the Sound Absorption and Mechanical Property of the Multi-Layer Needle-Punching Nonwoven
Authors: Tai Kou Cheng , Chen Pai , Lin Ching Wen , Lou Ching Wen , Tan Hsiu Mei , Lin Jia Horng
Published: August 2010

In this research, we used the special needle punching process to improve the disadvantages of the ordinary needle punching process. First, we manufactured the single-layer needle punching nonwoven by the ordinary needle punching process and then nonwovens were laminated followed by needle punching. We carried on this manufacturing processing until the multiple needle-punching nonwoven reached the certain thickness and area weight which were both limited in the ordinary needle punching process. The combination of two manufacture techniques as multiple thermal bonding and multiple needle-punching freed the single needle-punching from the limit of the expected thickness and area density. In this research, we tested the mechanical properties and sound absorption of the multi-layer needle-punching nonwoven and multi-layer thermal bonding nonwoven. According to the results, the tensile strength is higher than the multi-layer thermal bonding nonwoven; however, there was no distinct difference between the multi-layer needle-punching nonwoven and multi-layer thermal bonding nonwoven on the sound absorption performance.
A Generic Model for Predicting the Permeability of Fiber Mats
Authors: Dong Chen Song , Tang Tuong Yung
Published: August 2010

A new empirical model for predicting the permeability of fiber mats is presented in this paper. Permeability data were collected from the NIST reinforcement permeability database and categorized according to the material architecture. It is seen from the data that for each category, permeability is proportional to fiber volume fraction. In order to describe the behavior of permeability vs. fiber volume fraction, the location, scale and shape parameters were introduced for each material category. The model was validated against the experimental data and good agreement was found.
Block Copolymers on a Physically or Chemically Patterned Substrate
Authors: Kim Jaeup U.
Published: August 2010

Patterned substrates are good candidates to enhance the arrangement of nanodomains in block copolymer thin films. Here, I theoretically demonstrate the possibility to self-assemble block copolymers on top of physically or chemically patterned substrates. The presence of substrate pattern not only enhances the alignment of polymers, but also induces novel new morphologies which were not present in the bulk phase diagram.
Effects of Graphene on a Resin Transfer Molding Process Using Bisphenol A Based Epoxy Resin
Authors: Nguyen Huu Hieu , Lee Dae Woo , Troung Quang Trung , Yun Seong Woo , Choi Chi Hoon , Kang Hyun Min , Lee Sang Moo , Lee Dai Soo , Choi Soo Hyoung
Published: August 2010

Resin transfer molding is a popular process to fabricate polymer composites reinforced with a large amount of glass or carbon fibers. In general, fiber reinforcements are put in a mold, and a liquid resin such as epoxy resin is injected into the mold after preheating. For successful production of polymer composites via a resin transfer molding process, the filling and curing stages of the liquid resin as well as the mold design should be optimized. Recently, polymer composites reinforced with nanoparticles are attracting attention of researchers in academia and industries because efficient reinforcement can be achieved by small loading of nanoparticles such as carbon nanotubes and exfoliated clays. In this work, as an effort to develop light weight automotive parts, graphenes were investigated as a nano size reinforcement of epoxy resin for resin transfer molding. Graphenes were prepared from graphites by microwave irradiation. Addition of graphenes to bisphenol A based epoxy resins such as YD-128 from Kukdo Chemical results in an increase in viscosity and shear thinning behavior, affecting the filling process. The curing of epoxy resins is also affected by graphenes. In order to develop a model for simulation of the filling and curing of epoxy resins containing different amounts of graphenes in the resin transfer molding, FLUENT and MATLAB have been used in this study, which are a finite element based computational fluid dynamics analysis tool and a general purpose numerical analysis tool, respectively. The effects of graphenes on the mold filling pattern and curing profile are discussed for the resin transfer molding of bisphenol A based epoxy resins.
Numerical Simulation of Flash Butt Welding of High Manganese Steel Crossing with Carbon Steel Rail
Authors: Li Yan Guo , Zhang Fu Cheng
Published: August 2010

A flash butt welding model of a high manganese steel crossing was established using the thermal coupled finite element method (FEM). The model considers comprehensively the physical parameters of materials, which change with temperature, as well as the burning material caused by the splutter during welding process. The temperature field of the flash butt welding joint and the cooling curves of the high manganese steel crossing at various locations near the welding seam were simulated. Comparisons with actual welding specimens of high manganese steel crossing indicated that flash butt welding model of the high manganese steel crossing is reasonable, and the temperature field distribution near the welding seam after flash butt welding can thus be appropriately evaluated by the simulation results.
A Convenient Method for Preparing Well-Dispersed Er2Zr2O7 Nanocrystals
Authors: Tong Yu Ping , Zhang Rui Zhu , Zhao Shun Bo , Li Chang Yong
Published: August 2010

Well-dispersed fluorite Er2Zr2O7 nanocrystals have been successfully prepared by a convenient salt-assistant combustion method. The effects of calcinations temperature and salt category on the characteristics of the products were investigated by XRD and TEM. The thermal treatment temperature has an important effect on crystal size and lattice distortion of the nanocrystals. The experiment showed that the introduction of salt in the combustion synthesis process resulted in the formation of well-dispersed Er2Zr2O7 nanocrystals. The average size was 30 nm and was in agreement with the XRD result, which indicated that the nanocrystals were uniform in particle size distribution. Moreover, the possible formation process in the salt-assisted combustion synthesis was also analyzed.
Aggregation Characteristics of Cu and Ag Nanoparticles in Presence of Starch as the Polymer Stabilizer
Authors: Sinha Indrajit , Singh Manjeet , Mandal Rajiv Kumar
Published: August 2010

This presentation deals with the aggregation characteristics of Cu and Ag nanoparticles in presence of starch as the polymer stabilizer. Uncontrolled aggregation of the destabilized nanoparticles offers problem for applications based on surface plasmon activity. Polymer or small molecule surfactants are used to control nature of aggregation of nanoparticles produced by chemical reduction synthesis routes. Different growth models such as diffusion limited cluster aggregation (DLCA), reaction limited cluster aggregation (RLCA) proposed to explain the formation of fractal colloidal aggregates do not account for aggregate formation in presence of polymer or small molecule surfactants. We shall be discussing the role of starch on the aggregation characteristics of copper and silver nanoparticles formed by chemical reduction in aqueous conditions. The effect of NaOH concentration and consequently the pH on such aggregation kinetics during such synthesis is delineated. We use small angle x-ray scattering (SAXS) to quantitatively understand different aspects of aggregation behavior.
Consolidation and Mechanical Properties of Nanostructured SiC from Mechanically Activated Powder by High-Frequency Induction-Heated Sintering
Authors: Shon In Jin , Kang Hyun Su , Park Na Ra , Ko In Yong
Published: August 2010

The rapid sintering of nanostuctured SiC hard materials was investigated with high-frequency induction heating sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and prohibition of grain growth in nanostuctured materials. A dense nanostructured SiC hard material was produced with simultaneous application of 500 MPa pressure and induced current within 2 minutes. The effect of the ball milling times on the sintering behavior, grain size and mechanical properties of binderless SiC was investigated.
Electromagnetic Shielding Properties of Super Fiber-Reinforced Composites
Authors: Yang Hua , Yamanaka Atsuhiko , Ni Qing Qing
Published: August 2010

Electromagnetic shielding effect material is needed because electronic devices suffer electromagnetic interference. Otherwise, in many engineering designs such as antenna fairings, sonar cover and stealth aircraft, materials with good electromagnetic penetration are desired. High performance fiber-reinforced composites have high specific strength and mechanical properties, and there is therefore a need to develop an electronics enclosure with optimum shielding by using a combination of particular fiber reinforcements and a polymer matrix. This paper describes the development of high-performance fiber-reinforced composites that use four high strength fibers (super fibers), Dyneema SK60 (an ultra-high molecular weight polyethylene fiber), Zylon HM (poly-p-phenylenebenzobisoxazole fiber), Technora T-241J (aramid fiber) and Torayca T800HB (carbon fiber). These super fibers were fabricated by compression molding and their shielding effectiveness (SE) was tested. The results showed that the newly developed Dyneema fiber, Zylon fiber and Technora fiber composites exhibited low electromagnetic shielding properties of 1.3~2.3 dB at a frequency of 0.5~18 GHz. Furthermore, the Torayca fiber composite has high electromagnetic shielding properties of 10.2~20.7 dB at the same frequency. It is expected that these high-strength composites with optimum SE can be obtained by controlling the electromagnetic shielding properties from hybrid multi-fiber structures.
Hydrogen Storage Behaviors of Ni-Loaded Activated Carbon Nanotubes
Authors: Lee Seul Yi , Park Soo Jin
Published: August 2010

In this work, nickel (Ni)-loaded activated carbon nanotubes (ACNTs) were prepared for hydrogen storage applications. The process was conducted by chemical activation method at 900oC with KOH:CNTs ratios (4:1, g/g). And then, Ni-loaded ACNTs were also formulated to investigate the hydrogen storage characteristics as a function of Ni content. The microstructures of the Ni-loaded ACNTs were characterized by XRD and TEM measurements. The textural properties of the samples were analyzed using N2 adsorption isotherms at 77 K. The BET, D-R, and BJH equations were used to observe the specific surface areas, the micropore, and mesopore structures, respectively. The hydrogen storage capacity of the Ni-loaded ACNTs was measured at 298 K at a pressure of 100 bar. It was found that the hydrogen storage capacity of Ni-loaded ACNTs was enhanced in proportion to the Ni content, with Ni-5-ACNTs exhibiting the largest hydrogen storage capacity. Therefore, it could be concluded that the significantly created micropores on CNTs by chemical activation had an effect on hydrogen storage behaviors as well as the Ni particles played an important role in hydrogen storage characteristics due to the hydrogen spillover effect.
Influence of Potassium Chloride on the Electrochemical Deposition of ZnO Plate Films
Authors: Lü Xue Ming , Zou Xiao Ping , Cheng Jin , Yang Gang Qiang , Wei Cui Liu , Sun Zhe , Feng Hong Ying , Yang Yuan , Teng Gong Qing , Meng Xiang Min
Published: August 2010

KCl is usually used as the supporting electrolyte in electrochemical deposition of Zinc oxide materials. Besides the role of supporting electrolyte, it can also influence the morphology of the fabricated materials. In this work, ZnO and zinc hydroxide chloride hydrate (Zn5(OH)8Cl2•H2O) mixture with platelet-like morphology were electrochemically deposited directly on ITO-coated glass substrates at 65°C. The electrolyte was 0.1M Zn(NO3)2•6H2O with KCl concentration varied from 0 to 3.2M. It was found that only ZnO thin film was obtained when the concentration of KCl was below 0.02M. Plates structure appeared as the concentration of KCl increased to 0.04M. Plentiful plates were obtained when the concentration of KCl was 0.05M-0.2M. From the X-ray diffraction, it was confirmed that the plate films was the mixture of ZnO and Zn5(OH)8Cl2•H2O. The plates showed perfect single crystal structure confirmed by selected area electron diffraction. Zn and Zn5(OH)8Cl2•H2O were obtained when the concentration of KCl was above 0.8M.
Magnetic Properties of Single-Layered Fe100-xPtx Films by Rapid Thermal Annealing
Authors: Shen Chih Long , Sun T.H. , Chang C.L. , Chen Sheng Chi , Lin G.P. , Huang K.T. , Ou Sin Liang , Kuo Po Cheng
Published: August 2010

Fe100-xPtx single-layered films with Pt contents (x) = 32~69 at.% were deposited on natural-oxidized Si(100) substrate by dc magnetron sputtering. Then the films were post-annealed at 700 °C for 3 min by a rapid thermal annealing (RTA) with a high heating ramp rate of 100 °C/sec. Experimental results show that FePt film presented (111) preferred orientation and tended to in-plane magnetic anisotropy as the content of Pt was 32 at.%. When the Pt content was increased to 55 at.%, (001)-textured FePt film was obtained and presented perpendicular magnetic anisotropy. Its out-of-plane coercivity (Hc⊥), saturation magnetization (Ms) and out-of-plane squareness (S⊥) reached to 12.7 kOe, 375 emu/cm3 and 0.8, respectively. These results reveal its significant potential as perpendicular magnetic recording media for high-density recording. Further increasing the Pt content to 69 at.%, the coercivity of FePt film was decreased drastically to below 1 kOe and tended towards in-plane magnetic anisotropy.
Magnetic Properties of Some Hydrated Transition Metal Oxide and Hydroxide Nanoparticles Synthesized in Different Media
Authors: Bagabas Abdulaziz A. , Ziq Khalil A. , Salem Ahmad F. , Addurihem Emad S.
Published: August 2010

Nanoscale particle size of metal oxides and hydroxides showed enhanced various physical properties and performance. We established a simple, cost-effective, room-temperature (RT) precipitation method for the preparation of the magnetic, first-raw transition metal (TM) hydrated oxide and hydroxide nanoparticles. This method is based on the use of the TM nitrate, as the metal source, and cyclohexylamine (CHA), as a precipitating agent, either in the water (H2O) or ethanol (EtOH) medium. We found that the precipitation medium and the identity of precipitated TM strongly affect the morphology, particle size, and magnetism of the product. The morphology varies from spherical, to rectangular, to rod shape; while the size varies in the range of 5-30 nm. All samples showed paramagnetic behavior with Curie temperatures span over a wide range (20-150K). Huge hysteresis looses has been observed for manganese (Mn) sample, prepared in H2O. The coercively (Hc) at 4.2K for this sample is about 1.5T, which is comparable to the strongest permanent magnets (Nd-based magnets) available at room temperature. The energy product (Hc*MR) is about 4.5*105 (emu/g)Oe.
Evaluation of Recycled Far-Infrared/Impact-Resistant Poly(propylene) Composite Plates
Authors: Lin Jia Horng , Kuo Tung Lung , Lin Ching Wen , Lin Chin Mei , Hsieh Chien Teng , Lou Ching Wen
Published: August 2010

In recent year, the environmental consciousness is awakening; hence, the plastic recycling and reusing techniques have drawn much attention. In this paper, impact-resistant polypropylene(IRPP) chips were mixed with nano far-infrared master batches polypropylene(NFMPP) chips in different weight ratios. Then the polypropylene composite plates were formed by using a single screw extruder. Afterward, this study also simulated the plastics recycling procedure from 1 to 6 times, respectively. The results shown the average far-infrared emissivity of polypropylene composite plates were 0.90±0.02ε. In the IZOD measurement, the impact strength of polypropylene composite plate which processed for six times dropped by 20% comparing to the composite plate processed only once.
Microstructure and Crystallization Mechanism of (GeSbSn)100-xFex Phase Change Optical Recording Films
Authors: Ou Sin Liang , Kuo Po Cheng , Ma Shih Hsien , Shen Chih Long , Chiang Don Yau , Tang Wei Tai
Published: August 2010

The (GeSbSn)100-xFex films (x = 0 ~ 12.9) were deposited on nature oxidized silicon wafer, and glass substrate by dc magnetron sputtering. The ZnS-SiO2 films were used as protective layers. The thickness of the (GeSbSn)100-xFex film is 100 nm. We have studied the effects of Fe addition on the crystallization kinetics, and microstructures of the GeSbSn recording film. The crystallization temperatures of (GeSbSn)100-xFex films with x = 0, 7.1, 9.1, and 12.9 were found to be 225 °C, 198 °C, 167 °C, and 165 °C, respectively. The crystallization activation energies of (GeSbSn)100-xFex films with x = 0, 7.1, 9.1, and 12.9 are about 1.74 eV, 1.15 eV, 0.81 eV, and 0.52 eV, respectively.
Onion-Like Carbon Transformed from Nanodiamond
Authors: Zou Qin , Wang Ming Zhi , Li Yan Guo
Published: August 2010

Onion-like carbon (OLC) was fabricated by annealing nanodiamond at temperatures ranging from 500°C to 1400°C. At 800°C, nanodiamond was completely transformed into amorphous carbon. At 900°C, OLC began appearing. As the annealing temperature increased from 1000°C to 1200°C, OLC particles size became larger and larger and the amorphous carbon coexisted in the center of the OLC particle became less and less. At 1400°C, all the amorphous carbon was transformed into the OLC.
Synthesis of a Range of Functional Oxide and Sulphide Nanoparticles by Biopolymer Stabilization and Enzymatic Treatment
Authors: Walsh Dominic , Kim Yi Yeoun , Neudeck Carolina
Published: August 2010

Nanoparticles of the metal oxides magnetite (Fe3O4), cobalt oxide (Co3O4), manganese oxide (Mn3O4) and the metal sulfides CuS, Cu1.96S, Ag2S and CdS were prepared using the biopolymer dextran as a stablising agent. The corresponding enzyme dextranase could then used remove the biopolymer coat to give nanoparticles stabilized by a remnant oligomer. A green and aqueous general route to functional nanoparticles is described.
Temperature Effects on Synthesis of Multi-Walled Carbon Nanotubes by Ethanol 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 study, we report the synthesis of carbon nanotubes by ethanol catalytic chemical vapor deposition, which employs ferrocene as the catalyst precursors and ethanol as carbon source. We obtained massive deposits. The deposits were characterized by scanning electron microscopy, transmission electron microscopy, and visual laser Raman spectroscopy. We discussed the effects of synthesis temperature on the synthesis of carbon nanotubes by floating catalytic chemical vapor deposition. Our results indicated that the synthesis temperature could affect not only on the graphitization degree, but also on the aligned growth of carbon nanotubes and the diameter of carbon nanotubes.
The Effect of Holding Time on the Mechanical Properties and Microstructure of Sintered NbC Composite
Authors: Kang Duck Soo , Woo Kee Do , Kim Sang Hyuk , Shon In Jin , Kim Ji Young , Park Sang Hoon
Published: August 2010

High frequency induction heated sintering (HFIHS) method is one of the rapid sintering methods. The advantage of rapid sintering method is that grain growth can be prevented during sintering at high temperature. Refinement of grains was known to increase the yield and flow stresses of crystals. The relation between the yield stress and the grain size is known as Hall-Petch relation. NbC-10vol.%Co, Ni and Fe composites were fabricated by HFIHS at 1060°C for 0 and 3 min as holding times under a pressure of 80MPa.The relative density of NbC-10vol.%Co, Ni and Fe composites which were sintered at 1060°C for 0min as holding time under 80MPa were 91.90%, 91.26% and 91.26%, respectively. These composites are difficult to use industrial parts due to low relative density. The longer sintering time was conducted for increasing relative density in this study. Nano-sized specimens, which were calculated grain size by full-width at half maximum (FWHM), can be obtained by HFIHS. The value of hardness and fracture toughness was investigated using 20kgf load Vickers indenter.
A Nondestructive Study on Fiber Layup and Porosity Level in CFRP Composite Laminates Using Ultrasonic Pitch-Catch Method
Authors: Im Kwang Hee , Park Je Woong , Hsu David K. , Kim Sun Kyu , Cho Young Tae , Yang Yong Jun , Yang In Young
Published: August 2010

A nondestructive technique would be very useful for evaluating the CF/Epoxy composite laminates. It is found that a pitch-catch signal was more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composites (damages, fiber orientation, low level porosity, ply waviness, and cracks). The depth of the sampling volume where the pitch-catch signal came from was relatively shallow with the head-to-head miniature Rayleigh probes, but the depth can be increased by increasing the separation distance of the transmitting and receiving probes. Also, a method was utilized to determine the porosity content of a composite lay-up by processing micrograph images of the laminate. The porosity content of a composite structure is critical to the overall strength and performance of the structure. The image processing method developed utilizes a free software package to process micrograph images of the test sample. The results from the image processing method are compared with existing data. Beam profile was characterized in unidirectional CFRP (Carbon fiber reinforced plastics) with using pitch-catch Rayleigh probes and the one-sided and two-side pitch-catch technique was utilized to produce C-scan images with the aid of the automatic scanner. Also, it is confirmed that the pitch-catch ultrasonic signal was corresponding with simulated results assuming in unidirectional CFRP composites.
Internal Defect Inspection of Composite Material Using Non-Contact UT
Authors: Song Kyung Seok , Na Sun Young , Kim Jae Yeol
Published: August 2010

The NAUT technique allows non-contact ultrasonic testing in air. If the NAUT technique can be applied, not only ultrasonic testing in air with no couplant would be possible, but also the stable transmission and reception of ultrasonic waves, which would thus enable ultrasonic testing of hot or cold materials, or rough surfaces of specimens that could not be tested with conventional-contact ultrasonic testing techniques. By trying NAUT for CFRP (carbon fiber-reinforced plastic) specimens, the applicability of NAUT in these areas was observed, and the results from the waveforms of parts of the specimens were analyzed. To verify the usefulness of NAUT, first, artificially defective specimens were tested to investigate the defect detection ability of NAUT; and second, a test was conducted to select the test conditions, the ultrasonic propagation characteristics, and the mode conversion by the material thickness. Both the spot welding and CFRP specimens showed good applicability of NAUT. For the spot welding specimen, the ultrasonic transmittance was highest at the spot-welded part, regardless of the thickness and location of the specimen. For the CFRP specimen, the waveforms of a defective part and a defect-free part were compared, and the existence of delamination was discovered through the increase and decrease in the amplitude. These findings confirmed the practicality (usefulness) of NAUT.
Measurement of Bridge Fundamental Frequency by Resistance Strain Gauges
Authors: Zhao Shun Bo , Chen Ji Hao , Yao Ji Tao , Pei Song Wei
Published: August 2010

Normally, the structural fundamental frequency can be got from the vibration tests by means of accelerometers or velocimeters linked with the dynamic signal measuring and analysis system. Based on the principle of reinforcement strain variation synchronized with the structural vibration, the paper introduces a new method to obtain the fundamental frequency of bridge by measuring the environmental dynamic strains of resistance strain gauges bonded on the reinforcing bars of bridge hinge and deck pavement. The real-time strain signals caused by vehicles passed on the bridge were recorded by the dynamic signal measuring and analysis system, and transformed into strain spectrum by fast Fourier transformation in which the fundamental frequency was got. The result was the same as that of velocimeter measuring. Therefore, the bridge fundamental frequency can be simply and accurately measured by the resistance strain gauges.