bluuebunny/crossref_metadata_2025 huggingface dataset:
Content Based Image Retrieval Based on Log Gabor Wavelet Transform
Authors: Agarwal Megha , Maheshwari Rudra Prakash
Published: December 2011

This paper proposes a novel approach of content based image retrieval based on Log Gabor Wavelet Transform (LGWT). It is observed that LGWT better represents an image compared to Gabor Wavelet Transform (GWT). Experimental results illustrate the comparative analysis of proposed retrieval system and the retrieval system based on GWT feature descriptor. It is verified that LGWT based retrieval system improves the average precision and average recall (55.46% and 32.03% respectively) from GWT based retrieval system (50.61% and 31.63% respectively). All the experiments are performed on Corel 1000 natural image database.
Fingerprint Matching Based on Orientation Feature
Authors: Kumar Ravinder , Chandra Pravin , Hanmandlu M.
Published: December 2011

This paper presents a fast and reliable algorithm for fingerprint verification. Our proposed fingerprint verification algorithm is based on image-based fingerprint matching. The improved orientation feature vector of two fingerprints has been compared to compute the similarities at a given threshold. Fingerprint image has been aligned by rotating through an angle before feature vector is computed and matched. Row and Column variance feature vector of orientation image will be employed. The algorithm has been tested on the FVC2002 Databases. The performance of algorithm is measured in terms of GAR and FAR. At a threshold level of 1.1 % and at 5.7% FAR the GAR observed is 97.83%. The improved Feature vector will lower imposter acceptance rate at reasonable GAR and hence yields better GAR at lower FAR. The proposed algorithm is computationally very efficient and can be implemented on Real-Time Systems.
Rule Extraction from Privacy Preserving Neural Network: Application to Banking
Authors: Naveen Nekuri , Ravi V. , Rao C. Raghavendra
Published: December 2011

In the last two decades in areas like banking, finance and medical research privacy policies restrict the data owners to share the data for data mining purpose. This issue throws up a new area of research namely privacy preserving data mining. In this paper, we proposed a privacy preservation method by employing Particle Swarm Optimization (PSO) trained Auto Associative Neural Network (PSOAANN). The modified (privacy preserved) input values are fed to a decision tree (DT) and a rule induction algorithm viz., Ripper for rule extraction purpose. The performance of the hybrid is tested on four benchmark and bankruptcy datasets using 10-fold cross validation. The results are compared with those obtained using the original datasets where privacy is not preserved. The proposed hybrid approach achieved good results in all datasets.
An ID-Based Signature Scheme from Bilinear Pairing Based on Ex-K-Plus Problem
Authors: Mishra Shivendu , Yaduvanshi Ritika , Rai Anjani Kumar , Singh Nagendra Pratap
Published: December 2011

In an ID-Based cryptosystem, identity of users are used to generate their public and private keys. In this system private key is generated by trusted private key generator (PKG). Unlike traditional PKI, this system enables the user to use public keys without exchanging public key certificates. With the exploitation of bilinear pairing, several secure and efficient ID-Based signature schemes have been proposed till now. In this paper, we have proposed an ID-Based signature scheme from bilinear pairing based on Ex-K-Plus problem. The proposed scheme is existentially unforgeable in the random oracle model under the hardness of K-CAA problem. Our scheme is also unforgeable due to hardness of ex-k-plus problem and computationally more efficient than other existing schemes.
Web-Base Group Decision Support System for Information Security Decision Making in Case of Indian E-Government Systems
Authors: Gaigole Mayur , Khere Nilay
Published: December 2011

This paper presents a web base multicriteria group decision support system for evaluating information security policy decision making with respect to Indian e-government system. This study first proposes a rational-political group decision-making model which identifies three uncertain factors involved in a group decision-making process: decision maker’s roles in a group reaching a satisfactory solution, preferences for alternatives and judgments for assessment criteria. Based on the model, a linguistic term oriented multi criteria group decision-making method is developed. The method uses general fuzzy number to deal with the three uncertain factors described by linguistic terms and aggregates these factors into a group satisfactory decision that is in a most acceptable degree of the group. Moreover, this study implements the method by developing a web-based group decision support system. This system allows decision makers to participate a group decision-making through the web, and manages the group decision-making process as a whole, from criteria generation, alternative evaluation, opinions interaction to decision aggregation. An information security decision making problem is presented to demonstrate the effectiveness of the approach.
Image Processing Method Based on GIS System for Better Disaster Manag Ement
Authors: Mahor Sanjivani , Shrivastava Nishant , Dubey Ashutosh K.
Published: December 2011

A geographic information system (GIS), or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location(s). GIS is the merging of cartography, statistical analysis, and database technology, natural resource management, precision agriculture, photogrammetric, urban planning, emergency management, navigation, aerial video, and localized search engines.Today the concept of GIS is widely used in different areas of research and mankind. The disaster management systems are most based on GIS today, and the core idea of those systems is the past earthquake experiences. Remote sensing image processing can help government assess earthquake damage quickly. Taking this technology integrated with the quondam system can improve the assessment’s precision of this kind of system. In this paper, we discuss a method which quickly evaluates the earthquake damage. Firstly, we discuss different cases and quick evaluation of earthquake damage by means of GIS based system. Secondly, analyzes the result by quick assessment. Thirdly, integrating the image processing module with the old system to get the new system, in which the assessment’s precision can be improved.
Monitoring Compliance and Elastic Modulus in a Bioreactor for Optimal Control of Vascular Tissue Growth
Authors: Couet Frédéric , Meghezi Sébastien , Levesque Lucie , Mantovani D.
Published: December 2011

Functional vascular tissue engineering aims to produce blood vessels in vitro in a controlled environment named bioreactor. In order to control the growth and remodeling of vascular tissues, suitable measurements should be made on the construct in situ, i.e. during the growth. These measurements will feed the controller with information in order to take efficient control decisions. The non-destructive measurement of compliance or elastic modulus in vitro is a potential indicator of the vascular construct maturity. This work shows that compliance and elastic modulus are related: they can be estimated during the growth of constructs in a bioreactor, and thus provide useful feedback information to the controller.
Rheological Studies of an Injectable Radiopaque Hydrogel for Embolization of Abdominal Aortic Aneurysms
Authors: Fatimi Ahmed , Coutu Jean Michel , Cloutier Guy , Lerouge Sophie
Published: December 2011

Several embolizing agents have been tested for minimally invasive treatment of intracranial aneurysms, and more recently to prevent or treat persistent blood flow (endoleaks) in abdominal aortic aneurysms. However, frequent recurrence of endoleaks was seen in most studies, suggesting that current embolization agents are not satisfying yet. Here we report rheological studies of a radiopaque chitosan hydrogel as an embolizing agent. The aim is to provide an agent that would be visible during x-ray based guided interventions. In this study, a commercial contrast agent (iopamidol) was associated to chitosan at different concentrations and its influence on the rheological behavior of chitosan thermogel was evaluated. The resulting hydrogels have a homogenous coherent structure. The addition of iopamidol leaded to an initially more viscous solution. To have a good visibility of hydrogel via x-ray, an optimum iopamidol concentration of 20% v/v was chosen. The addition of 20% v/v iopamidol increased the gelation time. The use of a high βGP concentration constitutes a solution to overcome the slowing down of gelation by 20% v/v iopamidol. Formulations containing around 16-20% βGP provides viscous solutions which rapidly gel and could be promising injectable radiopaque hydrogels for embolization.
Synthesis and Characterisation of New Superelastic and Low Elastic Modulus Ti-Nb-X Alloys for Biomedical Application
Authors: Ramarolahy A. , Castany Philippe , Gloriant Thierry , Prima Frédéric , Laheurte P. , Eberhardt André , Patoor E.
Published: December 2011

Ti-Nb based alloys are well known to their good mechanical properties, shape memory effect, superelasticity, as well as good biocompatibility. The Ti-24Nb (at%) binary alloy presents a shape memory behavior and low elastic modulus. Our study is focused on the improvement of their mechanical properties by adding a third alloying element (oxygen, nitrogen or silicon). Addition of 0.5 at% of N or O modifies drastically the mechanical behavior of Ti-24Nb alloy that exhibits superelastic behavior instead of shape memory one. On the other hand, addition of 0.5 at% of Si increased yield strength of the Ti-24Nb shape memory alloy.
Improvement of Collagen Hydrogel Scaffolds Properties by the Addition of Konjac Glucomannan
Authors: Weska Raquel Farias , Achilli Matteo , Beppu Marisa Masumi , Mantovani D.
Published: December 2011

Collagen gels have been investigated for a number of applications in tissue engineering because of their excellent biological properties. However, their limited mechanical behavior represents a major bottleneck for clinical use, especially for vascular tissue engineering. The targeting of their mechanical properties may be envisaged by the addition of other biopolymers, such as konjac glucomannan (KGM), a neutral high-molecular weight polysaccharide extracted from the tubers ofAmorphophallus konjac, which has already been studied for biomedical applications due to its biocompatibility and biodegradable activity. In the present study, reconstituted collagen gels were prepared at pH 10 and room temperature, by mixing collagen with NaOH, NaCl and 0.05 to 0.2% of KGM. Collagen fibrillogenesis was monitored by spectrophotometric analysis at 310 nm. Gel samples were analyzed by compression tests, FTIR and SEM. Comparing to the control, the addition of KGM reduced the half-time (t1/2) of gelation fromca. 3 h to 2 h and the mechanical tests showed increases in the compressive strain energy of up to 3 times, and in compressive modulus of almost 4 times. Scanning electron images of collagen gel samples with KGM revealed the presence of micro-domains of KGM in the collagen matrix, revealing a phase separated scaffold for vascular tissue engineering.
Microstructure and Superconductive Property of MgB2/Al Composite Materials
Authors: Mizutani Manabu , Tokai Daisuke , Matsuda Kenji , Nishimura Katsuhiko , Kawabata Tokimasa , Hishinuma Yoshimitsu , Aoyama Shigeki
Published: December 2011

MgB2has the higher critical temperature of superconducting transition (TC: 39K) among the intermetallic compound superconductive materials, however, MgB2is hard for practical use because of its unworkable and lower critical current density (JC) in a high magnetic field than Nb-based superconductive materials. We have developed the original method of three-dimensional penetration casting (3DPC) to fabricate the MgB2/Al composite materials. In the composite material we made, MgB2particles dispersed to the matrix uniformly. Thus, these composite materials can be processed by machining, extrusion and rolling. TheTCwas determined by electrical resistivity and magnetization to be about 37～39K. In this work, we made composite material with ground MgB2particle with the purpose of extruding thinner wires of composite material, successfully produced φ1mm wire and changed the matrix from pure Al to Al-In alloy.JCof composite materials with the matrix of Al-In alloy was calculated from the width of the magnetic hysteresis based on the extended Bean model. The result was better than that of MgB2/Al composite material without Indium. Microstructures of these samples had been confirmed by SEM observation.
Microstructure of the New Route Wire Fabrication of V3Ga Compound Superconducting Wire Using High Ga Content Cu-Ga/V Precursor Composite Material
Authors: Murakami Satoshi , Mizutani Manabu , Matsuda Kenji , Nishimura Katsuhiko , Kawabata Tokimasa , Hishinuma Yoshimitsu
Published: December 2011

Our co-worker, Hishinuma et. al. has established a new route Powder-In-Tube (PIT) process using a high Ga content Cu-Ga compound in order to improve the superconducting property of the V3Ga compound wire. In this study, we investigated microstructure of this high Ga content Cu-Ga/V composite superconducting wire. The different contrasts of matrix, V-Ga phase and Cu-Ga core were observed by SEM observation in cross section of 19 multifilamentary wire. And V-Ga phase was confirmed by SEM mapping. The area fraction of V-Ga phase increased when Ga content increased from 30% to 50%. Thin film sample with V-Ga phase for TEM was fabricated by FIB and observed by TEM in detail. Selected area diffraction pattern was obtained for V matrix, V-Ga phase and Cu-Ga core. The ratio of V to Ga for V-Ga phase was probably V3Ga according to the EDS result. There was a linear interface between V matrix and V-Ga phase, while the interface between Cu-Ga core and V-Ga phase was not linear. On the other hand, there were some granular grains observed in V-Ga phase wear Cu-Ga core.
Fabrication of W-12wt%Cu Composites by Powder Metallurgy Method: Activated Sintering
Authors: Samei Javad , Green Daniel E. , Stoilov Vesselin
Published: December 2011

One of the most challenging areas in engineering of composite materials is the fabrication of high quality microstructures. This issue is complicated for tungsten composites due to its high melting temperature and this leads to limitations in terms of possible processing techniques. This research investigates the fabrication of W-12%wtCu composites based on powder metallurgy techniques. Due to the very large difference between the melting point of tungsten and copper, there is no common sintering temperature range for them. In this work, 0.5%Wt nickel was added as an activator to decrease the sintering temperature of tungsten using an activated sintering effect. The effects of pressure, sintering time and temperature in solid state and liquid phase conditions were also investigated. While solid state hot pressing did not result in appropriate microstructures, the liquid phase hot pressing provided high quality samples with a relative density of 98.0%.
Investigation of Friction Stir Welding of Stainless Steel Using a Stop-Action-Technique
Authors: Pfeiffer Christian , Weinberger Thomas , Schröttner H. , Mitsche Stefan , Enzinger Norbert
Published: December 2011

Especially for aluminium and its alloys friction stir welding (FSW) has become an established welding process. In contrast FSW for steel is still challenging and in basic research. Some reasons are the high price of the tungsten based tools, the durability of the tools and the low welding speeds. For further development of the process, it is necessary to understand the metallurgical changes in the stirred material during welding. In this work, a 4mm thick stainless steel plate (1.4301) was welded with different types of tungsten-alloyed tools. A so called stop-action-technique was used at the end of the weld and the sheet was quenched immediately to prevent metallurgical changes caused by slow cooling. During the process, the temperatures on the top of the welded plate, close to the tool shoulder (10 mm beside the weld centre line) and at the bottom of the plate, directly below the weld centre were measured. On the bottom side, the temperature was also measured 35mm in front of the end of the weld to compare the differences in the cooling rate. The measured peak temperatures ranged from 330°C on top to about 1200°C on the bottom of the specimen. Moreover rotational speed was varied up to 1200 RPM to test the possibility to reduce the process forces and spindle torque. In addition the influences of the welding process parameters on the microstructural changes were investigated. E.g. the average grain size was measured which ranged from 6 to 12 µm in the stirzone.
Effect of Grain Refinement on Residual Strain and Hot Tearing in B206 Aluminum Alloy
Authors: D'Elia Francesco , Ravindran Comondore , Sediako Dimitry
Published: December 2011

Aluminum-copper alloy B206 has an excellent potential for use in automobiles as suspension knuckles and control arms. The main shortfall of this alloy however, is its high susceptibility to hot tearing. Grain refinement has been shown to reduce hot tearing severity in Al alloys. In the present study, Ti-B grain refiner was added at two levels (0.02 and 0.05 wt% Ti) to B206 to investigate the effect on hot tearing. Residual lattice strain was measured for each condition using neutron diffraction. Equiaxed fine grains significantly reduced hot tears in the alloy, and this resulted in a lower magnitude of residual strain along the casting.
HRTEM Observation of Early Stage of Precipitation in Mg-Gd-Y Alloys
Authors: Nakagawa Daisuke , Kawabata Tokimasa , Matsuda Kenji , Ikeno Susumu
Published: December 2011

HRTEM observation was performed to clarify the early stage of precipitation in Mg-Gd-Y alloy aged at 473 K. The hardness increased with increasing aging time after quenching. The hardness increased slowly at early stage of aging, increased rapidly, and then reached to peak hardness. At as-quenching and the early stage of aging, the weak spots appeared at a half 100Mgin SAED pattern. The intensity of these weak spots changed to higher with increasing aging time. Monolayers on {100}Mgplanes and β” phase existed at this aging stage. Monolayers, β” phase, the precipitates with five layers corresponding the feature of (020)β’plane and β’ phase co-existed after the rapidly increasing of hardness. In the peak aged specimen at 473 K, both of β” and β’ phases co-existed and β’ phase were formed dominantly.
On the Onset of Dynamic Recrystallization in Steels
Authors: Varela-Castro Gonzalo , Cabrera Jose María , Prado J.M.
Published: December 2011

The knowledge of the flow behavior of metallic alloys subjected to hot forming operations is of particular interest for designers and engineers in the practice of industrial forming processes simulations (i.e. rolling mill). Nowadays dynamic recrystallization (DRX) is recognized as one of the most relevant and meaningful mechanisms available for the control of microstructure. This mechanism occurs during hot forming operations over a wide range of metals and alloys and it is known to be as a powerful tool which can be used to the control of the microstructure and properties of alloys. Therefore is important to know, particularly in low stacking fault energy (SFE) materials, the precise time for which DRX is available to act. At constant strain rate such time is defined by a critical strain, εc. Unfortunately this critical value is not directly measurable on the flow curve; as a result different methods have been developed to derive it. Focused on steels, in the present work the state of art on the critical strain for the initiation of DRX is summarized and a review of the different methods and expressions for determining εc is included. The collected data is suitable to feeding constitutive models.
Effect of Mo and Ni on Phase Separation in Fe-Cr=Mo-Ni Quaternary Alloys
Authors: Yang Ling Ling , Saito Yoshiyuki
Published: December 2011

Numerical simulation of phase separation in Fe-Cr-Mo and Fe-Cr-Ni ternary alloys and Fe-Cr-Mo-Ni quaternary alloys were performed with use of the Cahn-Hilliard equation for ternary and quaternary alloys. A new numerical model based on the Gauss-Seidel and Newton Raphson methods was utilized to obtain efficient and accurate solution.
Surface Modification and Functionalization of Oxide Nanoparticles for Superhydrophobic Applications
Authors: Brassard Jean Denis , Sarkar Dilip K. , Perron Jean
Published: December 2011

Oxide nanoparticles have tremendous technological applications in the present days in diverse fields. In this study, the surface modification and functionalization of hydrophilic silica (SiO2) and zinc oxide (ZnO) nanoparticles were performed to obtain superhydrophobicity. Monodispersive nanoparticles of SiO2were prepared by Stöber process using tetraethoxysilane (Si (OC2H5)4) as a precursor and ammonium hydroxide as a catalyst in a ethanolic solution. The surface modification of the silica nanoparticles were performed using fluoroalkylsilane (FAS-17: C16H19F17O3Si) molecules to obtain fluorinated silica nanoparticles of diameter varying from 50nm to 300nm. On the other hand, surface modification of zinc oxide (ZnO) nanoparticles was performed using stearic acid (C18H36O2) molecules to obtain methylated ZnO nanoparticles. These functionalized nanoparticles were characterized both in the form of powder as well as thin films. The bonding characteristics of FAS-17 molecules with SiO2and stearic acid molecules with ZnO were investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Nanostructured thin films of these functionalized oxide nanoparticles exhibit superhydrophobicity with contact angles over 150° with water roll-off properties. Such functionalized oxides nanoparticles, therefore, can be easily incorporated in coatings and paints for various applications in emerging technologies like biomedical applications, anti-corrosion, anti-icing, drag reduction and energy consumption reduction.
Evaluation of Residual Stress in SPR Joint by Neutron Diffraction
Authors: Haque Rezwanul , Beynon John H. , Kirstein Oliver , Wong Yat Choy , Durandet Y.
Published: December 2011

The feasibility of measuring residual stresses in Self-Pierce Riveted (SPR) joints by neutron diffraction was evaluated in this study. Despite the small dimensions involved, meaningful results were obtained. It was observed that residual stress in the rivet head was higher in the centre and lower at the edge. For the SPR joints examined, the maximum value of residual stress evaluated was 550MPa, compressive and occurred in the rivet leg. Stresses in material adjacent to the rivet wall and at a distance of three times the rivet radius from the rivet axis were not significant. The results are discussed with respect to the physical events involved during SPR.
Submicrocrystalline Structures and Tensile Behaviour of Stainless Steels Subjected to Large Strain Deformation and Subsequent Annealing
Authors: Shakhova Iaroslava , Belyakov Andrey , Kaibyshev Rustam , Kimura Yuuji , Tsuzaki Kaneaki
Published: December 2011

Tensile behaviour of two steels with submicrocrystalline structures, i.e. a 304-type austenitic steel and an Fe-27%Cr-9%Ni austenitic-ferritic steel, was studied. The starting materials were subjected to large strain rolling and swaging to a total strain of ∼4 at ambient temperature. The severe deformation resulted in a partial martensitic transformation and the development of highly elongated austenite/ferrite (sub) grains aligned along the deformation axis. In the cold worked state, the transverse grain/subgrain size was about 100 nm in the 304-type steel and about 150 nm in the Fe-27%Cr-9%Ni steel. The grain refinement by severe plastic deformation resulted in increase of ultimate tensile strength to 2000 MPa and 1800 MPa in 304-type and Fe-27%Cr-9%Ni steels, respectively. The phase transformation and recrystallization took place concurrently upon annealing, leading to the development of submicrocrystalline structure consisting of austenite and ferrite grains. No significant softening took place under annealing at temperatures below 600°C. The tensile strength was 1920 MPa in 304-type steel and 1710 MPa in Fe-27%Cr-9%Ni steel after annealing at 500°C for 2 hours.
Functional Properties of Nanostructured Ti-Ni SMA Produced by a Combination of Cold, Warm Rolling and Annealing
Authors: Facchinello Yann , Brailovski Vladimir , Georges Thomas , Prokoshkin Sergey
Published: December 2011

In this study, different combinations of cold and warm rolling routes are compared to determine the processing conditions that will best allow the production of nanostructured Ti-Ni shape memory alloy, while reducing mechanical damage from rolling and enhancing the material texture. The processed alloy is characterized using stress-free strain recovery and constrained stress recovery techniques, both in static and cyclic regimes. The results of such a comparative functional characterization of nanostructured Ti-Ni alloy obtained by five different manufacturing routes are discussed.
Influence of the Hot Rolling Process on the Mechanical Behaviour of Martensitic Steel
Authors: Asadi Mehdi , Palkowski Heinz
Published: December 2011

The increased demand for advanced high-strength steels (AHSS) is driven mainly by the need of the automotive industry to reduce weight and to improve safety. Beside good ductility and high strength, those steels have a high bake hardening (BH) effect, giving additional contribution to the strength of structural parts, subjected to the paint baking process. In this paper results are presented gained from hot rolled martenstitic steels. For the simulation of changing conditions within the final hot rolling process the specimens were hot deformed using different schedules changing reductions and temperatures been selected according to the non-recrystallization temperature By controlling the deformation temperature and the amount of strain below non-recrystallization during the thermomechanically controlled process it was possible to refine the martensitic steel structure, resulting in an improved strength and BH behaviour. A wide spectrum of mechanical properties could be obtained. The best strength and BH levels were recorded where the deformation was applied belowTnRXat the highest amount of strain.
Investigation of the Substructure Evolution within Grains of Different Orientations during Recrystallization in a Commercial Al Alloy
Authors: Sukhopar Olga , Kuzmina M. , Gottstein Günter
Published: December 2011

In the present study, the substructure within grains of different orientations was investigated by means of EBSD technique. A 70% cold rolled commercial AA8079L alloy was annealed at two temperatures, 280°C and 320°C, for short times from 2 to 60 seconds. The subgrain size within the deformed grains of different orientations was measured. The results revealed no pronounced difference in subgrain size right after cold deformation. During further annealing at both investigated temperatures, Cube grains showed the highest recovery rate. It is concluded that the Cube oriented nuclei require an incubation time which is, obviously, much smaller than for grains of other orientations.
’Quenching and Partitioning’ - An In Situ Approach to Characterize the Process Kinetics and the Final Microstructure of TRIP-Assisted Steel
Authors: Rieger Thomas , Herrmann Klaus , Carmele Dagmar , Meyer Stephan , Lippmann Thomas , Stark Andreas , Bleck Wolfgang , Klemradt Uwe
Published: December 2011

The ‘Quenching and Partitioning’ (Q&P) concept aims to increase the strength level of conventional TRIP-assisted advanced high strength steel (AHSS) by replacing ferritic constituents by tempered martensite. The Q&P heat treatment process involves austenitization and interrupted quenching followed by carbon partitioning from martensite to austenite at elevated temperatures. The final microstructure is traditionally investigated at room temperature after metallographic preparation by microscopy and x-ray analysis with laboratory tubes. Besides other disadvantages the established characterization methods are not adequate to observe the development of the microstructure during Q&P treatment. In the present work the microstructural evolution during Q&P processing was monitored by in-situ diffraction experiments using very hard (100 keV) synchrotron x-ray radiation. Debye-Scherrer rings were recorded as a function of time and temperature during the heat treatment in a state-of-the-art dilatometer (type Bähr DIL805AD) at the Engineering Materials Science beamline HARWI-II (HZG outstation at Deutsches Elektronensynchrotron (DESY), Hamburg). The diffraction patterns contain quantitative information on the phases present in the sample (for more details cf. Abstract Carmele et al, this conference). The evolution of the austenite phase fraction during the partitioning treatment at the quench temperature (1-step Q&P) is discussed exemplarily for a Si-based TRIP steel with additions of Ni.
Investigation on Properties of Bentonite Type in Cold Bonded Pelletization of Flue Dust
Authors: Chen Guan Jhou , Hwang Weng Sing , Liu Shih Hsien , Chou Jaw Min
Published: December 2011

In the integrated steel mills fabrication processes, the by-product of flue dust and electrostatic precipitator dust were found to be rich with large amounts of iron and carbon content and it could be recycled as a raw material for blast furnaces. In this study, we use the “Cold-bonded Pellet; CBP” technique to prepare the recycling samples for subsequent processing. Therefore, this study investigated under a fixed amount of bentonite added, the choice of different types of bentonite on the powder granulation performance and strength of particle duration effects, bentonite used as a basis for adjustment. The results showed that Bentonite samples of the granulation efficiency increase, relative to its yield and the rate of sticky increase. In general, CBP particle compressive strength increased, duration have increased, and found that curing condition B are large than the A method. In addition, by particle size analysis results show that, bentonite average particle size of 11-12μm have better compressive strength. Comprehensive assessment of granulation and mechanical properties, of which A label in four Bentonite can be preferred.
Microstructural Control of a Zn-Al Eutectoid Alloy by Hot-Rolling
Authors: Loc Nguyen The , Itoh Goroh , Yi Yi , Motohashi Yoshinobu , Sakuma Takaaki
Published: December 2011

The Zn-Al eutectoid alloy has been well known as a typical superplastic metallic material with small grain sizes. In the present study, controlling conditions in hot rolling such as temperature, total number of passes, reduction in a pass, etc. have been investigated in a ZnAl eutectoid alloy to obtain finegrained microstructures. Homogenized ingot specimens were hotrolled by a total rolling reduction of 90% with different pass schedule. Microstructural observation on the final sheet showed that nearly equiaxed finegrained microstructure with grain size of about 2µm was formed when the ingot was waterquenched after homogenization.
Micropatterning Polymer Materials to Improve Endothelialization
Authors: Boivin Marie Claude , Chevallier P. , Turgeon Stéphane , Lagueux Jean , Laroche Gaetan
Published: December 2011

Several studies have shown that 65 % of expanded poly (tetrafluoroethylene) (ePTFE) vascular prostheses had to be explanted within 10 years of implantation in humans. The reasons for these explantations relied on thrombosis formation and poor hemocompatibility of synthetic polymers. It has been shown that surface modification of ePTFE arterial prostheses could enable their endothelialization therefore improving their biocompatibility and hemocompatibility. Indeed, endothelial cells naturally cover the biological blood vessel wall and consequently, an endothelial layer constitutes the best achievable hemocompatible surface. In this context, our strategy consisted in micropatterning cell adhesion (RGD) and proliferation (WQPPRARI) peptides on the surface of plasma-functionalized PTFE, therefore enabling covalent conjugation of the peptides. Basically, the technology consisted in spraying a solution of the adhesion peptide, therefore leading to 10 µm-diameter RGD spots semi-randomly distributed over the sample and covering 20 % of the whole polymer surface. In a second step, proliferation peptide was applied to the remaining surface by soaking, therefore covering the unreacted surface. The 20 % coverage was obtained by using an x-y table, programmed to move from side to side of the surface on x value, with an increment on y value that has been calibrated.
Superhydrophobic Surface Elaboration Using Plasma Polymerization of Hexamethyldisiloxane (HMDSO)
Authors: Foroughi Mobarakeh L. , Jafari R. , Farzaneh M.
Published: December 2011

This study concerns the elaboration of a superhydrophobic coating on an aluminium alloy substrate by means of surface anodization and plasma polymerization. First, anodizing was used to create a micro/nanostructured aluminium oxide layer on the aluminium alloy substrate. Then, the resulting rough surface was coated with a plasma-polymerized hexamethyldisiloxane (HMDSO) film. The effects of several processing parameters such as input RF power (30 to 60 W) and deposition time (5 to 35 min), on the hydrophobic properties of the resulting films were investigated. Fourier Transform Infrared Spectrometry (FT-IR) analysis showed the important effect of the plasma power charge on the intensity of Si-CH3band which effectively influences the hydrophobic character of the coating. The static contact angle of the superhydrophobic film was also evaluated at low temperature, which showed that hydrophobicity of the coating was reduced at low temperature. Keyword: Plasma polymerization, Hexamethyldisiloxane, Superhydrophobicity, Icephobicity, Anodizing
Microwave Joining of Natural Fiber Reinforced Green Composites
Authors: Singh Inderdeep , Bajpai P. K. , Malik D. , Madaan J. , Bhatnagar N.
Published: December 2011

Natural fiber based bio-composites are gaining prime importance these days because of their high strength to weight ratio and environmental benefits. An increase in the application spectrum of these materials necessitates cost effective high quality processing in order to meet the stringent design requirements. In the present investigation, fully biodegradable natural fiber (grewia optiva) reinforced poly lactic acid (PLA) composite has been developed. The tensile strength of the composite has been found to increase by 75% of that of the neat polymer. The developed composites have been joined using the adhesive bonding and the microwave joining. The tensile shear strength of the joint has been experimentally evaluated and it has been found that the bond strength of adhesively bonded specimen (4.9% of the parent material strength) is substantially lower as compared to microwave joined specimen (62.85% of the parent material strength). The process of microwave joining has also been simulated using standard Multiphysics software and the results were in close agreement with the experimentally recorded values.
Preparation and Characterization of High Performance LLDPE/Graphene Nanocomposites
Authors: Kuila Tapas , Jung Bong Joo , Yi Xiao Fei , Lee Joong Hee
Published: December 2011

The nanocomposites containing linear low density polyethylene (LLDPE) and dodecyl amine (DA) modified graphene (DA-G) as nanofiller have been prepared by solution-mixing method and characterized. Transmission electron microscopy analysis of the nanocomposites exhibits homogeneous dispersion of graphene in the LLDPE matrix. Thermal stability of the nanocomposites with 1 wt.% DA-G are superior as compared to neat LLDPE. Gas barrier properties of the nanocomposites are also much better than that of the neat LLPDE. Co-efficient of thermal expansion values of the nanocomposites decreases with the addition of functionalized graphene. Keywords: Functionalized graphene; UV-Vis spectra; Nanocomposites; Gas barrier property; Mechanical property
Life Cycle Monitoring of Curved Composite Parts Using Embedded Fiber Bragg Grating Sensors
Authors: Takeda Nobuo , Minakuchi Shu , Umehara Takahide , Yusaku Ito
Published: December 2011

This study demonstrated fiber-optic-based life cycle monitoring of an L-shaped carbon fiber reinforced plastic (CFRP) part. Fiber Bragg grating (FBG) sensors were embedded in the corner of the L-shaped specimen during the laminate lay-up process, and was then utilized to monitor the local strain change during the cure process, the demolding, the assembly, and a subsequent bending test. FBG spectral changes induced were comprehensively presented and discussed from the viewpoint of the mechanical and thermal deformation of the specimen. Internal state of the L-shaped part was successfully monitored throughout its life, confirming effectiveness of life cycle monitoring by embedded fiber-optic-based sensors for developing highly-reliable composite structures.
Effect of Tool Angle on Friction Stir Welding of Aluminum Alloy 5052: Role of Sheet Thickness
Authors: Reddy P. Jayachandra , Kailas Satish V. , Srivatsan Tirumalai S.
Published: December 2011

The technique of friction stir welding (FSW) does offer several advantages over conventional welding techniques. In this paper is presented the results of an investigation aimed at understanding the effect of tool angle on welding of sheets of commercially pure aluminum and aluminum alloy AA5052-H32 having different thickness. The present study demonstrates the feasibility of using friction stir welding (FSW) for joining two different thickness sheets of commercially pure aluminum (t = 1.5 mm and t = 2.0) with sheets of aluminum alloy 5052-H32 having thickness of 1.6 mm and 2 mm. It was found that the tool angle does play a major role in the welding of sheets having different thickness. Formation of the FSW zone was analyzed both macroscopically and microscopically. The tensile properties of the joints were evaluated and correlated with the formation and presence of the FSW zone. From this study it was found that the tool angle for commercially pure aluminum having a thickness of 1.5 mm and 2.0 mm is 2.580. The tool angle is 1.910 for the sheets of AA 5052-H32 having a thickness of 1.6 mm and 2 mm. The joint efficiency of the friction stir welded AA 5052-H32 was 87.5 pct. when compared to the base material. The hardness was also observed to drop in the region of the weld. Key words: Friction stir welding, tool angle, aluminum alloy (AA5052-H32), Hardness, macrostructure, microstructure.
Evaluation of Surface Quality during Electrical Discharge Machining of Inconel 718 with Powder Metallurgy Electrodes
Authors: Beri Naveen , Maheshwari S. , Sharma C.
Published: December 2011

In recent years, researchers have reported powder metallurgy processed electrodes as alternative tooling for electrical discharge machining (EDM). The present experimental study evaluates the quality of machined surface during electrical discharge machining (EDM) of Inconel 718 alloy steel with powder metallurgy (PM) processed electrodes. The investigated process parameters were polarity, electrode type, peek current, pulse on time, duty cycle, gap voltage, retract distance and flushing pressure. The surface quality was measured in terms of surface roughness (Ra). An orthogonal array L36 (21X 37) based on Taguchi methodology was applied to plan and design experiments. Experimental data was statistically analyzed using analysis of variance (ANOVA) and optimum condition was achieved for evaluation criteria. It was concluded that polarity, electrode type, peek current, have significant effect on surface quality and minimum Ra is obtained with CuW2080 electrode at minimum current and negative polarity. Deposition of tungsten with CuW2080 (80%W 20%Cu) electrode was confirmed by energy dispersion spectrum (EDS) of the machined surface.
Optimization of the Process Parameters for Drilling of Metal Matrix Composites (MMC) Using Taguchi Analysis
Authors: Singh Sarbjit , Singh Abhishek , Singh Inderdeep , Dvivedi Akshay
Published: December 2011

Drilling of MMCs is considerably difficult due to the presence of extremely hard reinforcement which causes rapid tool wear and influences the cutting forces and quality characteristics. The present investigation aims at studying the effect of drilling parameters (cutting speed, feed rate and the drill point geometry) on the output responses such as, thrust force (TF), specific cutting pressure (SCP) and surface roughness (SR). Taguchi’s technique has been applied to obtain an optimal setting for drilling process parameters for optimizing the output quality characteristics.
Deformation Mechanism Maps for Al-Cu-Mg Alloys Micro-Alloyed with Tin
Authors: Robi P.S. , Banerjee Sanjib , Srinivasan A.
Published: December 2011

High temperature deformation behavior of Al–5.9%Cu–0.5%Mg alloy and Al–5.9%Cu–0.5%Mg alloy containing 0.06 wt.% of Sn was studied by hot compression tests at various temperatures and strain rates. Addition of trace amounts of Sn into the Al–Cu–Mg alloy system resulted in a significant increase of flow stress for all conditions of temperature and strain rate. 100% and 89% of the flow stress values during hot deformation could be predicted within ± 10% deviation values for the aluminum alloys with and without Sn content, respectively, by artificial neural network (ANN) modeling. From the deformation mechanism maps and microstructural investigation, the safe process regimes for hot working of the base alloy was identified to be at (i) very low strain rate (< 0.003 s−1) at temperature < 450 °C, and (ii) high temperature (> 400 °C) with strain rate > 0.02 s−1. For the micro-alloyed alloy, it was at low strain rates (< 0.01 s-1) for the entire temperature range studied. Flow softening for both alloys was observed to be at low strain rates and was identified to be due to dynamic recrystallization (DRX). The metallurgical instability during deformation was identified due to shear band formation and/or inter-crystalline cracking.
Cutting Model in Machining of Al/SiCp Metal Matrix Composite
Authors: Nikouei Sayed Mohamad , Yousefi R. , Kouchakzadeh Mohammad Ali , Kadivar M.A.
Published: December 2011

Prediction of shear plane angle is a way for prediction of the mechanism of chip formation, machining forces and so on. In this study, Merchant and Lee-Shaffer theories are used for prediction of shear plane angles and cutting forces in machining of Al/SiCpMMC with 20% of SiC as reinforcement particles. The experimental cutting forces are compared with the calculated cutting force based on shear plane angles extracted from Merchant and Lee-Shaffer theories. The variation of these cutting forces with cutting speed, feed rate and depth of cut has been discussed. The results showed that Merchant theory may be used as a good method for prediction of chip formation in machining of Al/SiCpMMC.
Study on the Relationship between the Hydrogen Bond and Damping Properties of Nitrile-Butadiene Rubber/Hindered Phenol Composites by Molecular Dynamics Simulation
Authors: Hu Tao , Bo Qiao , Zhao Xiu Ying , Wu Si Zhu
Published: December 2011

This work was try to study the relationship between the damping properties and the hydrogen bonds, fractional free volumes of nitrile-butadiene rubber (NBR)/hindered phenol (AO-80) composites from the microstructural point of view by combining the experimental and molecular simulation studies. The results indicated that the hydrogen bonds (HBs) were formed between AO-80 small molecules and NBR polymer chains. According to simulation results, because of the formed strongest HBs, highest binding energy and the smallest fractional free volume in the NBR/AO-80 composites with the blending ratio of 100/68, it contributed the maximum loss factor and highest modulus. It concluded that there was a suitable proportion of rubber blended with small hindered phenol molecules in the design of damping materials.
Compressive Behavior of Glass Fiber Reinforced Plastic Laminates with Drilled Hole
Authors: Rakesh P. K. , Singh Inderdeep , Kumar D.
Published: December 2011

The polymer matrix composites (PMCs) are increasingly being used in structural applications owing to their superior mechanical properties. The in-service performance of composite materials requires them to perform under a variety of loading environments. Although a lot of research work has been done towards the mechanical characterization of PMCs, a lot remains to be done in special cases such as characterization of glass fiber reinforced plastics (GFRP) laminates with drilled hole. It is an established fact that drilling in composite laminates causes damage around the drilled hole and the damage influences the mechanical behavior of GFRP laminates under different loading conditions. The present investigation aims at studying the compressive behavior of GFRP laminates with drilled holes. The holes have been drilled at various input parameters (cutting speed, feed rate and drill point geometry) and the effect of these parameters on the compressive behavior of the GFRP laminates has been investigated using statistically designed experiments. It has been found that the drilling parameters significantly affect the compressive behaviour of laminates with drilled holes.
Advances in Semiconductor Nanostructures for Photonic Applications
Authors: Yu Paul K.L. , Yu Edward T. , Wang De Li
Published: December 2011

In this paper we present the concept and demonstration of novel photovoltaic and electro-optic devices, and photoelectrochemical cells based on various semiconductor nanostructures, specifically compound semiconductor quantum wells and nanowires, and the use of plasmonic and related scattering effects from metal or dielectric nanoparticles to increase efficiency of optical absorption. Quantum-well solar cells were fabricated with scattering from metallic or dielectric nanostructures incorporated to direct incident photons into lateral, optically confined paths with high electromagnetic field intensity within relatively thin multiple-quantum-well regions to maximize quantum efficiency of photon absorption. The internal structure of quantum wells in quantum-well solar cells was also analyzed and characterized; the incorporation of a suitable potential step within each quantum well was explored for improvement in power conversion efficiency. Vertical nanowire arrays were engineered to optimize optical confinement within the nanowires, and core-shell heterostructures were employed to achieve broad-spectrum absorption while maintaining high open-circuit voltages. Large linear electro-optic effect is observed in the nanowire arrays. Branched nanowire photoelectrochemical cells were also made and characterized for their spectral incident photon-to-current conversion efficiency. These works have been sponsored by U.S. Department of Energy and National Science Foundation.
The Effects of Fiber Architecture and Fiber Surface Treatment on Physical Properties of Woven Sisal Fiber/Epoxy Composites
Authors: Srisuwan Sawitri , Chumsamrong Pranee
Published: December 2011

The aim of this work was to investigate the effects of fiber architecture and fiber surface treatment on flexural and impact properties of woven sisal fiber/epoxy composites. The woven sisal fibers with three different weave types including plain weave (P-weave), harness satin weave (S-weave) and right hand twill weave (R-weave) were used. For untreated fiber/epoxy composites, the fiber contents in the composite were 0, 5, 10 and 15% by weight (%wt). The untreated S-weave sisal fiber/epoxy composites showed the best overall properties and the composites with 15% fiber loading showed the highest properties. When compared to pure epoxy, flexural strength, flexural modulus and impact strength of the composite with 15% wt fiber increased by 4.5%, 60.6% and 150% respectively. Therefore, the composite of 15% wt silane treated S-weave and epoxy was prepared in order to study the effect of fiber surface treatment. The results showed that the composite containing 15% wt silane treated fiber possessed nearly the same properties with the untreated fiber/epoxy composite.