bluuebunny/crossref_metadata_2025 huggingface dataset:
Bluetooth Based 12- Channel Temperatures Data Acquisition System
Authors: Yaseen Amer Atta
Published: December 2011

The trend in industrial control has been to reduce the communications wiring across a plant. Eliminating the cabled connection between a sensors and a host computer enhances the performances and the manageability of a data acquisition system. Through the use of Bluetooth technology the data acquisition components can be paired with a wide variety of pre-existing devices. This makes the host computer portable, cheaper and versatile. Data is collected from the sensors by a microcontroller with an attached Bluetooth module, which transmits the data to a host computer for processing. Costs are reduced by making use of pre-existing processing power and display on the host computer. Depending on the application the data can be processed in any way required on the host computer. This paper describes the practical design of Bluetooth based 12- Channel temperatures acquisition system which contains remote temperature sensors connected to a microcontroller which controls also the Bluetooth module transmission, and a computer connected to a Bluetooth adapter. In this way, the sensors data are collected and processed by the microcontroller, transmitted via Bluetooth to a host computer which monitoring and recording the temperatures measurements.
A Novel Approach to Secure Communication Using Audio Steganography
Authors: Srivastava Mayank , Rafiq Mohd Qasim
Published: December 2011

The digital information revolution has brought important changes in our society and life. Nowadays, large amount of data is transmitted over the network and if the data that is being transmitted is important, one should use secure technique like steganography to transmit it. Steganography is a method of hiding a secret message in a cover media such as text, image, audio etc. in a way that hides the existence of the secret data. This paper introduces new method for audio steganography. The proposed method works on the basis of low bit blind encoding scheme which is used to embed secret data into non-silent samples of wav audio file. Robustness and performance of the proposed scheme is investigated by performing experiments on different audio signals.
Communication and Control through Words and Power
Authors: Issac Reji M.
Published: December 2011

Cognition and Communication are two processes that are interrelated through the sciences Noology and Electronics. Cybernetics is the art and science of understanding, which connects these two sciences together. In an age where human rights are inclusive of transformation of a human as a Cyborg, man and machine are closely working together, where machine intelligence means connecting machines with Noosphere. As we all know the basic difference between human beings and animals are with respect to thinking, where humans are more endowed with divine qualities and powers, which are controlled through the Words. Humans are also involved in the creation of the Words through their creative abilities. This paper aims to describe an idea about the communication and control through an invisible media known as Noosphere, where exchange of Words, generation of Words, rearrangement of Words, elimination of Words and modification of Words are done in the Heart and we inform the world about the invention of the Word. We use a methodology of analogous comparison with the communication through the Electromagnetic waves over a perfect conductor, where the media is a perfect conductor of words known as Holy Spirit. It also uses an analogy with electrons. This paper can be considered as a key paper related with Control, Cybernetics, Noology and Electronics, which gives the ultimate in all communication technologies and the ultimate status of Noosphere prophesied by intellectuals, through which Cybernetics can be raised to its original thought as the Science of Government, without any fear about unscrupulous Governments. This paper discusses how power is controlled through words and explains the weirdness in Control, Electronics, Computer Communications, and the Cyberspace communications. The communication system developed through this media can be called as Sky Mail or S-MAIL.
An Advanced Security and Data Integrity Protocol for Vehicular Ad-Hoc Networks
Authors: Farooq Mohd. Umar , Pasha Mohammad , Khan Khaleel Ur Rahman , Atif Mahboob Ul Haq
Published: December 2011

MANETS is a kind of ad-hoc network which is continuously changing and not predictable. The nodes in this kind of network are mobile and reorganize themselves randomly. Mobility of these nodes keeps changing from time to time. These nodes are connected using wireless connections to form an ad-hoc network called VANETS. In VANETS (vehicular ad-hoc network) the mobile nodes are vehicles which are equipped with their own resources to carry out the communication (like power, software etc). This paper deals with analyzing the vulnerabilities of VANETS and achieving data integrity and security by providing some authentic means of communication and standards. It describes a protocol which provides prevention against malicious node and how the network reacts in the presence of the malicious node. Using the concept of reliability tables, the paper describes a methodology to dynamically re-create a new route whenever a malicious node is interfaced thus achieving data integrity and security.
Ultrasonic Setup for Testing Hydrogels: Preliminary Experiments on Collagen Gels
Authors: Irastorza Ramiro M. , Achilli Matteo , Amadei Marta , Blangino Eugenia , Drouin Bernard , Mantovani D.
Published: December 2011

The assessment of mechanical properties of highly hydrated natural materials remains a challenge because, in general, their mechanical evaluation implies invasive and finally destructive methods. Acoustic-based tests may represent the appropriate tools to investigate the mechanical properties of such materials, particularly collagen gels, whose acoustic properties are poorly understood. The objective of this work is to develop two experimental setups for the assessment of acoustic properties of such a hydrogels. In the first one, a typical pulse echo reflectometer was implemented. The acoustic parameters were measured at controlled temperature in an especially designed chamber. In the second one, the previous configuration was combined with a setup for compressive tests, allowing to interrogate simultaneously both the acoustic and mechanical properties of the sample under test. The frequency of the acoustic transducer was 10MHz. The acoustic and mechanical properties of collagen gels prepared according to different experimental conditions (pH and collagen concentration) were evaluated. The first set of experiment was useful to accomplish estimation of the speed of sound, attenuation and acoustic impedance. The second one allowed us to monitor the speed of sound during the evolution of the compression test. This approach could be a potential tool to study the changes in hydrogels mass density and bulk compressibility.
Polysaccharides Grafting on Fluorocarbon Films Deposited by Plasma on 316L Stainless Steel for Long Term Stable Stent
Authors: Michel Eléonore , Chevallier P. , Barrère Amélie , Letourneur Didier , Mantovani D.
Published: December 2011

Metallic intravascular stents are medical scaffolds commonly used to heal diseased arteries and to restore blood flow in vessels after a balloon angioplasty. Although clinical complications occurs (mainly in-stent-restenosis, representing 30-40% of cases within six months after angioplasty), this clinical procedure reduces the risk of restenosis. In order to improve the long-term clinical performances of stents, different coatings, bioactives or not, are investigated. However, the adhesion of the coating within the substrate is often weak and delamination after stent deployment could be observed. Therefore, our approach was to consider a plasma fluorocarbon film deposit on stainless steel substrates, improving adhesion and providing protection against the stent corrosion, as a carrier for the subsequent grafting of a polysaccharide (dextran). Indeed, a copolymer made of dextran and metacrylate has already demonstrated interesting results toward cell proliferation and appropriate mechanical properties regarding stent deployment. Hence, the aim of this project is to covalently graft the copolymer of dextran-methacrylate to plasma-aminated fluorocarbon film. In this study, dextrans were functionalized in order to conjugate them to amino groups. Two different ways of functionalization were investigated: by carboxylmethylation reaction and by periodate oxidation. Characterizations were performed by FTIR, for organic syntheses and by XPS for the subsequent grafting on the surface. Coatings topography and stability were also investigated. Preliminary results suggest the use of polysaccharides grafted by plasma on fluorocarbon films to provide a stable stent surface.
Influence of Mixing Parameters on the Density and Compaction Behavior of Carbon Anodes Used in Aluminum Production
Authors: Azari Kamran , Alamdari Houshang , Ammar Hany , Fafard Mario , Adams Angelique , Ziegler Donald
Published: December 2011

The current study investigates the effects of mixing parameters on the quality of anode paste and green anode used in aluminum electrolysis. Four mixing times and four mixing temperatures were applied to prepare anode pastes using calcined petroleum coke and coal tar pitch, as raw materials. The volume of the pores in the paste was used as the indicator for mixing effectiveness. A compression test was applied to the pastes to study the compactability of these pastes and to investigate the effect of mixing parameters on density of the green samples. It was shown that mixing parameters influence the size, volume and surface area of paste porosity and also its compaction behaviour.
Improving Friction Stir Welding between Copper and 304L Stainless Steel
Authors: Imani Yousef , Givi M.K. Besharati , Guillot Michel
Published: December 2011

As a solid-state welding technology, friction stir welding (FSW) can join dissimilar materials with good mechanical properties. In this paper, friction stir welding between 304L stainless steel and commercially pure copper plates with thicknesses of 3 mm was performed. A number of FSW experiments were carried out to obtain the optimum mechanical properties by adjusting the rotational speed to 1000 rpm and welding speed in the range of 14-112 mm/min and with an adjustable offset of the pin location with respect to the butt line. Microstructural analyses have been done to check the weld quality. Cross-sectioning of the welds for metallographic analysis in planes perpendicular to the welding direction and parallel to the weld crown was also performed. The mechanical properties of the welds were determined using a combination of conventional microhardness and tensile testing. From this investigation it is found that the offset of the pin is an essential factor in producing defect free welds in friction stir welding of copper and steel.
The Effects of Heat Treatment and Cold Working on the Microstructure of Aluminum Alloys Welded by Friction Stir Welding (FSW) Technique
Authors: Mohammadtaheri M. , Haddad-Sabzevar M. , Mazinani Mohammad
Published: December 2011

The application of hot deformation during Friction Stir Welding (FSW) gives rise to produce a weld nugget consisting usually of dynamically recrystallized grains whose size is substantially lower than that of the base material. In the present study, several specimens with different conditions were first prepared using 2024 and 5083 aluminum alloys, which were then welded with FSW method. The microstructures of weld nugget in both series of specimens were examined using optical and scanning electron microscopes. The specimen of 2024 with anneal (O) and artificial aging (T6) conditions, and type 5083 with anneal (O), 30% and 50% cold work conditions were friction stir welded. Grain size distribution, hardness and temperature profiles in the welded zones were determined in order to obtain the relationship between the grain structure and the hardness profile in these regions. In each alloy, the average grain size in the weld nuggets was identical. The hardness of nugget zones in each alloy was the same due to their similar microstructures. According to the results obtained in this investigation, the initial microstructure showed no considerable effect on final microstructure and hardness of the weld nuggets, which this effect may be attributed to continuous dynamic recrystallization phenomenon.
Consolidation of Ti Powder by a Compression Rotation Shearing System at Room Temperature - Effect of Pivot Rotation Speed on Consolidation
Authors: Nakayama Noboru , Kato S. , Takeishi Hiroyuku , Miki Hiroyuki
Published: December 2011

Ti has high strength, good corrosion resistance, is lightweight and shows good biocompatibility. It has thus been used extensively for mechanical and medical structural components. On the other hand, the disadvantages of Ti include a high melting point, ease of oxidization at high temperatures, low specific heat and low thermal conductivity. There are three specific problems associated with Ti metallurgy. The first is that powder metallurgical processing requires high temperatures and a high vacuum, the second is that samples produced by existing powder metallurgy techniques have a low density, and the third is the occurrence of burning because of a local temperature rise during the cutting process. Therefore, in the present work, a new high-speed, room-temperature molding process involving compression rotation shearing was developed. This method can be used for solidification of metal powders by enforced plastic flow and breaking of oxide films. Therefore, no external heat is required and the molding time is short. The proposed method represents an easy approach to consolidating high melting point metallic materials.
Effect of Al and Mn Contents on Microstructure in AM-Series Magnesium Alloys
Authors: Tsuchiya Taiki , Watanabe Katsumi , Matsuda Kenji , Kawabata Tokimasa , Sakakibara Katsuya , Yamaguchi Tomoyasu , Saikawa Seiji , Ikeno Susumu
Published: December 2011

Magnesium alloys containing aluminum have been used for industrial materials due to their lightweight and recyclability. And the Mg-Al based alloys are usually used for the industrial production. The Mg17Al12 phase is reported as the precipitate formed in the Mg-Al alloys during aging after the solution heat treatment, which is the discontinuous precipitate in the grain boundary and continuous precipitate in the matrix. The Mg-Al alloys are divided into AZ-series alloys with the addition of Zn, and AM-series alloys with the addition of Mn, respectively. AM-series and AZ-series Mg-Al alloys have been used for industrial products widely, particularly for AM-series alloys because of better toughness and impact absorption properties than AZ-series alloys. However, there is few report about the effect of Al and Mn contents on age-hardening behavior and microstructure of AM-series alloys. The propose of this study is to investigate the difference of the age-hardening behavior and microstructures of AM-series alloys using hardness test and scanning electron microscopy (SEM) observation.
Study of Micro Droplet Impingement Process of Molten Lead-Free Solder by Inkjet Printing Process
Authors: Wu Cheng Han , Lin Hsiao Lan , Hwang Weng Sing
Published: December 2011

An investigation of molten metal droplet impingement on substrate was conducted. Micro droplets of molten lead-free solder; Sn_3.0wt%Ag_0.5wt%Cu, were ejected at 230°C by using a piezoelectric inkjet printing process. The droplets were squeezed out from nozzle with orifice diameter of 50 µm by applying a voltage pulse of bipolar waveform. In this study, micro droplets with various velocities were deposited onto flat substrate. Spread factors of solders are at the range of 1.23-1.25. With the aid of numerical simulation, interfacial heat transfer coefficients between molten solders and substrate were observed to rise with droplet impact velocity. Though analyzing the data of simulation results, the mathematical relation between interfacial heat transfer coefficient and potential and kinetic energy shows the trend of direct proportion.
Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling
Authors: Xiao B. , Palmiere Eric J. , Howe A.A. , Carey H.C.
Published: December 2011

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology, widely applied in HSLA steel plate production. However, there are still certain limitations, especially for thicker plate. The rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during finishing. Intermediate Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time, can restrict austenite grain growth, and can also improve the subsequent strain penetration in thick plate with further metallurgical benefits. Multi-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of IFC. Clearly it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens, and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate thickness. However, some aspects of the gradients were addressed with tests using cold platens. The results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.
FE Simulation of Metal Orthogonal Cutting Processes Based on 3D Adaptive Remeshing Procedure
Authors: Zhang Jie , Cherouat Abel , Borouchaki Houman
Published: December 2011

Metal orthogonal cutting process involves complex geometry deformation and mate-rial characteristics as large thermal-visco-plastic ow include ductile damage. Simultaneously,the contact with friction occurs in the same zone. To build the nite element model for metalcutting, the nite element mesh will be severely distorted at the region with high gradientof stress/strain/temperature eld. In this paper, a Adaptive remeshing procedure which inte-grates the 3D OPTIFORM mesher, ABAQUS/Explicit solver and eld node-node eld transferalgorithm are proposed to solve these problems. The thermal-mechanical simulation for metalorthogonal cutting is realized to demonstrate our numerical simulation approach. Some simu-lation results are illustrated include continuous chip forming process, thermal-mechanical elddistribution and cutting force in di erent rank angles, cutting speeds and friction conditions.
Analysis on Behavior of Hydrogen in Ion-Plated Pure Aluminum
Authors: Iwahashi Hideki , Itoh Goroh , Saitoh Katsuhiro , Shikagawa Takahiro
Published: December 2011

An increasing interest has been being taken in hydrogen as a clean energy for solving the global environmental problems. In order to use the hydrogen in safety, investigation on the hydrogen behavior is required. Although hydrogen microprint technique (HMPT) has been known to be effective to investigate the hydrogen behavior, the low detection efficiency for hydrogen was reported. Ion-plating (IP) was reported to increase the detection efficiency in HMPT emitted from the specimen by plastic deformation. On the other hand, no such increase was found for hydrogen permeating through the specimen ion-plated with substrate heating in the previous study by the authors. In the present study, the sheet samples of pure aluminum with 99.99% purity were dehydrogenated and subjected to (a) holding in the IP chamber, (b) bombardment with Ar ions, (c) substrate heating after the bombardment and (d) holding in air. Hydrogen behavior in these samples has been investigated by means of thermal desorption spectroscopy (TDS). The amount of desorbed hydrogen was evidently larger in the conditions of (a) and (b) than in (d). However, the amount of desorbed hydrogen was decreased by the substrate heating (c) to the same level as in (d).
Temperature Changes during Deformation of Polycrystalline and Nanocrystalline Nickel
Authors: Chan T. , Backman David , Bos R. , Sears T. , Brooks I. , Erb Uwe
Published: December 2011

Commercially available polycrystalline nickel (grain size: 30 µm) and electrodeposited nanocrystalline nickel (grain size: 30 nm) were analyzed for the effect of stress-induced heat generation during plastic deformation at room temperature. Tensile coupons in conformance to ASTM E8 standard were tested at a strain rate of 10-1/s to record the amount heat dissipated using a high resolution infrared detector. The maximum temperature increases recorded for nanocrystalline and polycrystalline nickel close to sample fracture were 58°C and 70°C, respectively. Grain growth in nanocrystalline nickel due to stress-induced heat generation is unlikely since the maximum temperature during deformation is below the previously reported onset temperature for grain growth in nanocrystalline nickel.
Synthesis and Characterization of Organic-Inorganic Layered Perovskite Compounds Using Fullerene Derivatives
Authors: Hamaguchi Ayumi , Yoshizawa-Fujita Masahiro , Takeoka Yuko , Rikukawa Masahiro
Published: December 2011

Layered perovskite (RNH3)2PbI4 (R = organic cation), which contained the fullerene derivatives, [ethyl-3-tert-butoxycarbonylaminopropyl (1,2-methanofullerene C60)]-61,61-di carboxylate iodide (EAF-I) and di [3-tert-butoxycarbonylaminopropyl (1,2-methanofullerene C60)]- 61,61-dicarboxylate diiodide (DAF-I2) in the organic layers were fabricated and compared with previously reported perovkite compound containing N-methyl-2-(4-aminophenyl)-fulleropyrrolidine iodide (AmPF-I). Because the solvent solubilities of EAF-I and DAF-I2 to N,N-dimethylformamide (DMF) were higher than AmPF-I, the film processability of EAF-I and DAF-I2 was improved compared with AmPF-I. The X-ray diffraction patterns proved the construction of the perovskite structure in (EAF)2PbI4 and (AmPF)2PbI4 cast films. EAF was well-organized and closer-packing than AmPF in the perovskite structure. For the diamine-type fullerene, DAF-I2, it is difficult to form layered structure by spin-coated or cast methods. New sharp X-ray diffraction peaks were observed for DAF-I2 films dipped in PbI2 solution. The intercalations and formation of perovskite structure of (DAF)PbI4 were studied.
Synthesis and Characterization of Polythiophenes Having Phosphonate Ester Groups
Authors: Katagiri Maki , Yoshizawa-Fujita Masahiro , Takeoka Yuko , Rikukawa Masahiro
Published: December 2011

Polythiophene derivatives containing a phosphonate ester group, poly [3-(3-diethyl-phosphonate) propoxythiophene] (PEPPT), were synthesized by Rieke and oxidative polymerization methods. These PEPPTs were soluble in polar organic solvents such as methanol, DMF, and chloroform. Thehead-to-tailratio of PEPPT (Rieke) was estimated to be 98 % by1H NMR spectroscopy, while that of PEPPT (Oxidative) was estimated to be 53 %. The maximum absorption peak of PEPPT (Rieke) was observed at 596 nm, which was 46 nm longer than that of PEPPT (Oxidative) in CHCl3solutions. This result suggests that the planarity of PEPPT (Rieke) is higher than that of PEPPT (Oxidative) due to the high regioregularity of the side chains. The estimated band gap of PEPPT was 1.60 eV for Rieke-synthesized derivatives. The XRD peak of PEPPT(Rieke) was observed at 5.14º (17.2 Å) and that of PEPPT (Oxidative) was not clearly observed, suggesting that PEPPT(Rieke) has self-organized properties to form a layered structure.
Strain Hardening in Polycrystalline and Nanocrystalline Nickel
Authors: Tang B.T.F. , Erb Uwe , Brooks I.
Published: December 2011

The work hardening behavior of electrodeposited nanocrystalline (grain size: 100 nm) and fully annealed polycrystalline nickel (grain size: 160 µm) was examined by hardness indentation analysis. First, plastic strain was introduced into the materials through large Rockwell hardness indentations. A series of Vickers micro-hardness traces below and away from the Rockwell indentation then measured the change in hardness as a function of distance from the plastic zone. The results showed that polycrystalline nickel exhibited considerable strain hardening, with micro-hardness values closest to the Rockwell indentation averaging twice the hardness value of the bulk material. On the other hand, for the nanocrystalline nickel the Vickers micro-hardness values changed only by a few percent indicating a limited strain hardening capacity.
Rheo-Extrusion of Hypereutectic Al-14.8Si-4.5Cu-1.1Mg Alloy
Authors: Mori Nanako , Uetani Yasuhiro , Dohi Masayoshi , Matsuda Kenji , Ikeno Susumu
Published: December 2011

Rheo-extrusion of hypereutectic Al-14.8%Si-4.5%Cu-1.1%Mg (in mass%) alloy which is considerably difficult to hot-extrude was tried using semi-solid slurry with fine solid granules and almost finely dispersed primary Si particles, made by a newly developed rotor process. Trials of rheo-extrusion at the constant extrusion ratio of 36 using this semi-solid slurry were carried out at the different conditions of the extrusion temperature and the ram speeds ranging from 520 to 560oC and from 5 to 20mm/s, respectively. Under the all rheo-extrusion conditions, this semi-solid slurry could easily be rheo-extruded to the round bars of 6mm diameter with sound surface at much lower extrusion force than that of hot-extrusion at very low extrusion ratio. In addition, the characteristic age-hardening behavior which is thought to be essential for the rheo-extrusion process has been found out, namely the peak hardness values of aged bars rheo-extruded at 520 and 540oC were considerably higher, 30HV at maximum, than that of a gravity casting.
Deformation Induced Pearlite Transformation and Spheroidization: Effect of Alloying Additions
Authors: Caruso Matteo , Verboomen Hector , Godet Stéphane
Published: December 2011

The aim of this research is to investigate the effect of Cr and Al (strong ferrite formers) on the strain-induced γ-to-pearlite transformation in eutectoid steels. The microstructure evolution during the hot deformation of three eutectoid steel grades was investigated using hot torsion testing. More specifically, the steels were deformed to strain levels varying from ε = 0,5 to ε = 1,5 at their specific Ar1 temperature. Hot deformation of the undercooled austenite leads to strain-induced γ-to-pearlite transformation and to the almost instantaneous spheroidization of the formed carbides. The corresponding microstructures consist of submicronic cementite particles and ferritic grains that are 1-5 μm in size. It is shown that 1,5% Cr addition and 0,5% Al addition increase the equilibrium transformation temperature but slower significantly the kinetics of the strain-induced transformation and consequently reduce the kinetics of cementite spheroidization and of ferrite recrystallization.
Microstructure and Deformation Behavior of a Hot Forged 9%Cr Creep Resistant Steel
Authors: Fedorova Irina , Yanushkevich Zhanna , Belyakov Andrey , Kaibyshev Rustam
Published: December 2011

The tempered microstructure and the creep behaviour were studied in an ultra low carbon 9%Cr martensitic creep resistant steel. The starting material was forged at 1050°C followed by air cooling and then tempered at a temperature of 750°C for 3 hours. This treatment resulted in the mean transverse lath size of about 240 nm; the dislocation density in lath interiors comprised 4 × 1014 m-2. The tempered martensite lath structure (TMLS) is characterised by homogeneous precipitation of numerous MX-type carbonitrides and a small amount of relatively coarse M23C6–type carbides. Three kinds of MX carbonitrides were observed in the tempered lath martensite structure. Those were plate-shaped particles with longitudinal size of about 15 nm and thickness of 3 nm; round-shaped particles of about 10 nm in diameter; and relatively large almost equiaxed particles with mean size of about 90 nm. The large MX particles were resulted from incomplete dissolution of such carbonitrides at 1050°C, while the nanoscale particles homogeneously precipitated during the tempering. The creep tests conducted at 650°C showed that the studied steel demonstrated superior creep resistance. Namely, the rupture time was about an order as long as that for P92-type creep resistant steel.
Effect of Microstructure on Formation of Ductile Fracture Surface in Steel Plate
Authors: Fukahori Tomoaki , Suzuki Shinichi , Yamada Naoya , Aramaki Masatoshi , Furukimi Osamu
Published: December 2011

In recent years, high strength steel plates for building and pipelines have been required to improve ductile fracture properties, assuming ground deformation in earthquake-prone region. The ductile fracture is performed by the result from coalescence of micro-voids followed by the nucleation and growth [1]. Fractured surface morphology reflects the void coalescence process, so it is important to consider the relationship between the fracture surface morphology and the micro-voids formation beneath the fractured surface to consider the ductile fracture properties. The voids nucleate sites are mainly particles such as inclusions or precipitates, and grain boundries. These voids grow and coalesce according to three modes. The first mode is directly coalescence of voids followed by growth [2]. The second one is the coalescence of voids caused by shear deformation followed by internal necking between voids [3]. The third one is the coalescence of voids caused by micro-voids nucleation in shear band between two larger voids [4]. It is expected that these modes influence local elongation property which is one of the indices for ductile fracture property through the formation of fractured surface. In this study, local deformation energy which is measured by load-displacement curve in tensile test is examined by focusing the voids nucleation, growth and coalescence, for high tensile strength plates of TS480-830MPa which is controlled by the microstructure through the cooling rate of heat treatment. The deformation energy is useful to consider the ductile fracture property of steel plates which have a different tensile strength.
Topological Analysis of Martensite Morphology in Dual-Phase Steels
Authors: Sato Naoko , Ojima Mayumi , Morooka Satoshi , Tomota Yo , Adachi Yoshitaka
Published: December 2011

Martensite morphology such as connectivity or dispersivity in ferrite (F)/martensite (M) dual-phase (DP) steels was investigated from topological viewpoint to reveal the effect of the martensite morphology on the mechanical properties. Topological analysis permits evaluation of the microstructural connectivity and dispersivity by measuring the number of handles, independent bodies and genus, etc. The topological analysis was performed on three-dimensional (3D) reconstructed images of the microstructure with different connectivity, dispersivity, volume fraction and hardness of martensite in DP steels that were prepared by changing the intercritical annealing temperature. The connectivity and the volume fraction of martensite increased while the dispersivity and hardness of it decreased with increasing annealing temperature. The effect of connectivity and dispersivity as well as volume fraction and hardness, in particular, on work hardening behavior was individually evaluated at a given strain.
Bubble Structures, Fishscaling Resistance and Adhesion of Vitreous Enamel to Low Carbon Steel
Authors: Zhang Ai Wen , Jiao Si Hai , Jiang Zheng Yi , Wei Dong Bin
Published: December 2011

The bubble structures, fishscaling resistance, adhesion and its mechanism of vitreous enamel to low carbon steels were evaluated by microscopic methods. The results show that the microalloying elements deteriorates the adhesion but suppress the fishscaling tendency, the enamel-steel interface adhesion could be explained as mainly the mechanical interlocking and chemical bonding during the firing process; the lower carbon substrate causes higher proportion of bigger bubbles in the enamel layer and subsequently causes the lower fishscaling susceptibility.
Effect of Electric Field Treatment on Vacancy of Inconel 718 Superalloy at 1073 K
Authors: Wang Yao , Wang Lei , Zhang Xin Yu , Li Yan Long , Liu Yang , Chao Yue Sheng
Published: December 2011

Effect of electric field treatment with different intensities on vacancy of Inconel 718 aged at 1073 K was investigated. The positron annihilation lifetime (PAL) and corresponding concentration of vacancies were measured by positron annihilation technique. It was found that atomic vibration at lattice site can be promoted by an external electric field performed on Inconel 718 superalloy during aged at elevated temperature. Some atoms owing the higher vacancy formation energy or larger radius will jump out from the normal lattice sites and form defects, which is leading to the increase of PAL of monovacancy. Under continuous effect on electric field, monovacancies will transform to three-dimensional vacancies of lower energy and vacancy clusters. Moreover, the vacancy concentration of Inconel 718 superalloy can be improved evidently by electric field treatment, and the average PAL of vacancies can be up to 6.3% when the electric field intensity is up to 8 kV/cm, which is very useful for controlling the microstructures evolution and properties of the superalloy, such as solute redistribution and precipitations.
Preparation of Photocatalytic TiO2 Filter by Chemical Surface Treatment from Ti Non-Woven Fabric
Authors: Kondo Masaki , Asaoka Teruo
Published: December 2011

Photocatalytic titanium dioxide (TiO2) filter was prepared by hydrothermal treatment in NaOH (8M) at 80°C followed by ion exchange in HCl (0.1M), and calcination at 400°C from Ti non-woven fabric (NIKKO TECHNO, Ltd.). Ti non-woven fabric is made of metallic Ti fibers. The surface area of the fabric is several times larger than flat Ti plate, so the TiO2 filter prepared from it should have high degradation ability of organic pollutants by photocatalyst. And we thought it could be applied for the filter to purify air or water. The sample was investigated by scanning electron microscope (SEM), and energy dispersive x-ray spectrometer (EDS). The photocatalytic activity of the sample was evaluated by degradation of methylene blue (MB) solution. The change of concentration of MB solution was measured by ultraviolet visible spectrometer (UV-vis). After the hydrothermal treatment, micro network structure layer was formed on the surface of Ti. The structure was maintained after heat treatment. The elements of the layer after heat treatment were Ti and O. The sample exhibited the degradation ability of MB solution. We tried to hybridize of the TiO2 filter and hydroxy apatite (HAp : Ca10(PO4)6(OH2) ) to improve degradation efficiency by adsorption ability of HAp. The hybrid material of them were prepared by soaking the TiO2 filter into simulated body fluid (SBF) at 37.5°C for 1~7d. Then, HAp particles were formed on the surface of the TiO2 filter. But the degradation ability was lower than non-hybrid sample.
Biology Inspired Superhydrophobic Surfaces
Authors: Victor J. J. , Facchini D. , Palumbo G. , Erb Uwe
Published: December 2011

In this study, the surface structure of a self-cleaning, superhydrophobic leaf was examined using electron microscopy and optical methods, and its wetting properties were measured using a contact angle goniometer. Using the micro/nanostructural surface features of this leaf as a blueprint, an inexpensive surface structuring technique was developed by modifying the surface of nanocrystalline nickel to create a template. These templates were then pressed into softened polyethylene at elevated temperatures and pressures, thereby transferring the structured surface to the polymer samples. All templates and pressed polymers were characterized in the same manner as the leaves. This method increased the wetting angle for polyethylene from 96° to 151° and reduced the tilt angle from 38° to <5°.
Formation of Deformation-Induced Divorced Eutectoid Pearlite above the Ae1
Authors: Basabe Vladimir V. , Jonas John J. , Ghosh Chiradeep
Published: December 2011

A 0.21% C plain carbon steel was deformed in torsion to strains of ε = 0.15-3.0 at a strain rate of ε ̇= 4.5 s-1 over the temperature range 722-822°C in a 5%H2-Ar gas atmosphere. The experimental parameters were varied in order to study the formation of ferrite and pearlite by dynamic transformation (DT) in the intercritical region. This transformation was observed right up to the highest experimental temperature (822°C). The pearlite formed by DT contained cementite spheroids whose size distribution evolved during isothermal holding after deformation. In the first stage, corresponding to the first 800 s of holding, spheroid coarsening took place. When the holding time exceeded 800 s, the spheroids dissolved and the pearlite reverted into the original parent austenite. The results indicate that pearlite can form by DT at temperatures well above the Ae1 and that the reverse static transformation is much slower than the forward dynamic transformation.
Behavior of Hydrogen in Electrolytically Charged Aluminum
Authors: Tsutsumi Tomohiro , Watakabe Takahito , Itoh Goroh
Published: December 2011

Investigation on the behavior of hydrogen is needed to spread the use of hydrogen fuel cell vehicles. Hydrogen microprint technique (HMPT) has been known as an effective method to investigate the hydrogen behavior by visualizing the microscopic location of hydrogen in relation to the microstructure. In the present study, the behavior of electrolitically charged hydrogen in 6061 and 7075 aluminum alloys with T6-temper has been investigated by means of HMPT. Both in the two alloys, hydrogen was detected on constituent particles and in the matrix. Total amount of detected hydrogen was markedly larger in 7075 than in 6061, although the distribution in depth direction far narrower and the fraction of hydrogen detected in the matrix with respect to that on the constituent was larger. These fact was presumed to be caused by the difference in the fine precipitates between the two alloy formed during final aging treatment.
Degradation Mechanism of Tungsten Electrode for Fusing Joining
Authors: Ishii Sho , Itoh Goroh , Mukae Shingo , Itoh Nobuhide
Published: December 2011

Lifetime of tungsten electrodes for fusing was investigated in relation to their microstructure. Tungsten electrodes with two types of microstructures (recrystallized equi-axed and unrecrystallized fibrous) were subjected to repeated welding tests where work material was a tough pitch copper. Surface appearance of the electrodes after the test was observed with an SEM. Circumferential edge cracks were observed in the equi-axed electrode, which were presumed to be initiated by plastic flow of the work material. Although cracks were formed in the center of both types of electrodes, the total length of them is longer in the equi-axed electrode. Therefore, the lifetime was expected to be longer in the fibrous electrode than the equi-axed.
Friction Stir Welding of Al-Li AA2199: Parameters, Precipitates and Post Weld Heat Treatment
Authors: Ivanov Rosen , Boselli Julien , Denzer Diana , Larouche Daniel , Gauvin Raynald , Brochu Mathieu
Published: December 2011

The aerospace industry strives to develop materials allowing an increase in payload and reducing fuel consumption. Al-Li alloys, with their low density and high strength are currently in use for such applications and have potential for additional applications. When compared to composites, utilizing Al-Li alloy products is cost effective for aerospace companies as they do not need to redesign pre-existing fabrication facilities. The joining of these alloys by conventional methods is limited by segregation of alloying elements and the formation of oxides during high temperature exposure. This study focuses on solid state joining method that has the potential to generate low heat and be defect free - Friction Stir Welding (FSW). AA2199 sheets were joined by FSW. Process variables included table force, tool rotation speed and weld travel speed. A post weld heat treatment (PWHT) was applied to improve the mechanical properties by precipitation of strengthening phases. An increase in hardness of the weld zone from 95HV to 125HV upon PWHT was recorded for selected welding conditions. The type and morphology of second phase precipitates is deemed responsible for this effect. It is suggested that the high temperature and high strain levels characteristic of welds with fast tool rotation allow for the dissolution of precipitates during welding. The re-precipitation of these second phases during PWHT allowed the welds to recover strength to the level of the base material.
Determination of Global and Local Tensile Behaviours of Laser Welded Ti-6Al-4V Alloy
Authors: Abu Syed Humaun Kabir , Cao Xin Jin , Gholipour Baradari Javad , Wanjara Priti , Cuddy Jonathan , Birur Anand , Medraj Mamoun
Published: December 2011

In this study, the global and local tensile behaviours of laser welded 5.1-mm thick Ti-6Al-4V alloy were obtained at various welding speeds and defocusing distances using a digital image correlation (DIC) technique with a full field three-dimensional deformation measurement system. The local tensile properties including elastic modulus, yield stress, and maximum plastic strain were determined at various locations by assuming an iso-stress condition. It was found that the elastic modulus and yield stress were maximum in the fusion zone (FZ) and minimum in the heat-affected zone (HAZ). Porosity and underfill defects were the main reasons for the failures in the FZ and/or the HAZ. Maximum plastic strain at fracture was observed at the failure location in most cases.
Brazing of Cemented Carbides at Lower Temperatures
Authors: Yaoita Shinji , Watanabe Takehiko , Sasaki Tomohiro
Published: December 2011

Cemented carbides have been widely used for cutting tools because of their high hardness and abrasion resistance. Since the cemented carbides are so expensive, it is desirable to reuse a tool shank made of cemented carbides. For the reason, so far, a new blade of a tool has been brazed to used shanks. However, when cemented carbides are heated for brazing, heating inevitably causes the deterioration in the mechanical properties. This study was carried out to braze the cemented carbides at lower temperatures for reducing the deterioration of the shank. First of all, authors developed a new Ag-based brazing filler metal with a low melting point of about 605°C, and investigated the effects of the new Ag filler metal on the properties of a brazed joint. Moreover, Co element or Ni element was added into the Ag filler metal to make the bending strength of a brazed joint improved. The addition of Co element increased the bending strength of a joint and the strength was equivalent to that of a joint brazed at 750°C using a conventional Ag filler metal, but the addition of Ni element decreased the bending strength of a brazed joint.
Studies on Shielded Active Gas Forge Welded API 5CT L80 Material at Different Cooling Rates
Authors: Vinothkumar P. , Ganesan S.M. , Solberg Jan K. , Salberg B. , Moe P.T.
Published: December 2011

Shielded Active Gas Forge Welding (SAG-FW) is a solid state bonding process in which two mating surfaces are locally heated and forged together to form a bond. SAG-FW has so far mainly been used to join materials for pipe-line and casing applications. The present study has been conducted on an API 5CT L80 grade material in a prototype forge welding machine. Small-scale pipe specimens have been extracted from the wall of the production casing. The SAG-FW process is completed within a few seconds of heating and forging followed by controlled cooling. The microstructure of the weld is determined by the processing parameters. In this paper, microstructure results for SAG-FW processed L80 material have been obtained for a range of cooling rates and systematically compared with microhardness values. Microstructure observations at different regions of the weld have been made. Faster heating rate and controlled cooling resulted in a mixture of non equilibrium microstructures, but satisfactory mechanical properties have been obtained for optimized processing parameters.
Silk Fibroin: A Promising Biomaterial
Authors: Agostini de Moraes Mariana , Silva Mariana Ferreira , Weska Raquel Farias , Beppu Marisa Masumi
Published: December 2011

Silk fibroin (SF) is a protein fiber spun by Bombyx mori silkworm. SF fibers are about 10-25 μm wide in diameter and a single cocoon may provide over 1000 m of SF fibers. SF can present several conformations regarding protein secondary structure which ultimately define the structural properties of SF-based materials. For this reason, a rigorous control on its processing conditions shall be performed. It is known that SF has excellent properties to be used in biomaterials field, controlled release and scaffolds for tissue engineering. In addition, SF can be processed in several forms, such as films, fibers, hydrogels or microparticles. This work seeks to provide an overview on SF processing conditions, regarding the preparation of SF membranes (dense and porous), hydrogels and biocomposites, focusing on biomaterials application.
Assessing Heat-Treatment Effects on Bovine Cortical Bones by Nanoindentation
Authors: Lau Mei Ling , Lau Kin Tak , Ku Harry , Bhattacharyya Debes , Lee Joong Hee
Published: December 2011

Among different sterilization methods, heat-treatment of bone is recognized as one of the simple and practical methods to lower the human immunodeficiency virus (HIV) infection and overcome the risks of rejection and disease transfer from allograft and xenograft during bone transplantation. In order to best characterize the micro-structural mechanical property of bone after heat treatment, the nanoindentation technique was applied in this study to measure the localized elastic modulus and hardness for interstitial lamellae and osteons lamellae of bovine cortical bones at temperature 23°C (room temperature-pristine specimen), 37°C, 90°C, 120°C and 160°C, respectively. The elastic modulus (E) and hardness (H) of interstitial lamellae obtained higher values as compared with osteons lamellae which show that interstitial lamellae are more stiff and mineralized than osteons. Moreover, as a specimen pre-heat treated at 90°C, the E and H values of interstitial lamellae and osteons were closed to a pristine specimen. For a specimen pre-heat treated at 120°C, both interstitial lamellae and osteons obtained an increase in E and H values. As a specimen pre-heat treated at 160°C, the interstitial lamellae and osteons obtained a slight decrease in E and H values. These findings are correlated to results reported by other researchers [1, 2] that calcified collagen molecules starts to degenerate at about 120°C and complete at 160°C. Interestingly, when a specimen was pre-heat treated at 37°C, both interstitial lamellae and osteons obtained significant decreases in E values of 57% and 40%, respectively as compared to the pristine specimen; while in H values, there was a decrease of 27.4% and 15%, respectively. Thus, this paper will investigate the mechanical properties of bovine cortical bones under various temperature ranges by nanoindentation technique.