bluuebunny/crossref_metadata_2025 huggingface dataset:
Software Design
Authors: Misra Rachita , Panigrahi Chhabi Rani , Panda Bijayalaxmi , Pati Bibudhendu
Published: September 2015

This chapter on “Software Design” emphasizes the role of modeling, prototyping, and simulation in software design. The chapter introduces the principles of software design, issues and challenges. Modeling techniques used in procedural and object oriented methodologies is presented along with the Unified Modeling Language (UML). The suitability of prototyping, as a design artifact and a simulation method is briefly discussed. Software processes such as Rapid Application Development (RAD), Rational Unified Process (RUP) and Agile methodologies which influence the design process have been discussed and recommended. The chapter then deals with Design Metrics for Quality Analysis, Software Risk Analysis and Threat Modeling for design of secure software. Finally, some of the recent research topics such as Model Driven Architecture (MDA), Model Driven Development (MDD), Meta Object Facility (MOF), and Model Driven Testing (MDT) have been covered.
Numerical Modeling of RC Bridges for Seismic Risk Analysis
Authors: Delgado Pedro Silva , Arêde António , Pouca Nelson Vila , Costa Aníbal
Published: September 2015

The main purpose of this chapter is to present numerical methodologies with different complexities in order to simulate the seismic response of bridges and then use the results for the safety assessment with one probabilistic approach. The numerical simulations are carried out using three different methodologies: (i) plastic hinge model, (ii) fiber model and (iii) damage model. Seismic response of bridges is based on a simplified plane model, with easy practical application and involving reduced calculation efforts while maintaining adequate accuracy. The evaluation of seismic vulnerability is carried out through the failure probability quantification involving a non-linear transformation of the seismic action in its structural effects. The applicability of the proposed methodologies is then illustrated in the seismic analysis of two reinforced concrete bridges, involving a series of experimental tests and numerical analysis, providing an excellent set of results for comparison and global calibration.
How to Support Strategic Decisions in Territorial Transformation Processes
Authors: Bottero Marta , Ferretti Valentina , Mondini Giulio
Published: September 2015

Territorial transformations can be regarded as a multifaceted concept which includes socio-economic, ecological, technical, political and ethical perspectives. Decision problems in the domain of territorial transformations represent “weak” or unstructured problems since they are characterized by multiple actors, many and often conflicting values and views, a wealth of possible outcomes and high uncertainty. This paper addresses decision problems in the context of urban and territorial planning projects using the Multi Attribute Value Theory (MAVT), a particular kind of Multiple Criteria Decision Analysis method and it provides an application on a real case located in the city of Torino (Italy).
Semantic Based Annotation for Surveillance Big Data Using Domain Knowledge
Authors: Xie Feng , Xu Zheng
Published: September 2015

Video surveillance technology is playing a more and more important role in traffic detection. Vehicle's static properties are crucial information in examining criminal and traffic violations. Image and video resources play an important role in traffic events analysis. With the rapid growth of the video surveillance devices, large number of image and video resources is increasing being created. It is crucial to explore, share, reuse, and link these multimedia resources for better organizing traffic events. With the development of Video Surveillance technology, it has been wildly used in the traffic monitoring. Therefore, there is a trend to use Video Surveillance to do intelligent analysis on vehicles. Now, using software and tools to analyze vehicles in videos has already been used in smart cards and electronic eye, which helps polices to extract useful information like plate, speed, etc. And the key technology is to obtain various properties of the vehicle. This paper provides an overview of the algorithms and technologies used in extracting static properties of vehicle in the video.
The Information Gap amongst the Generations and the Implications for Organizations
Authors: Kiser Angelina I. T. , Washington Ronald
Published: September 2015

The ubiquitous nature of technology today fosters the perception that its use as a means of information sharing and gathering occurs equally across resources. There is however a digital divide which commonly refers to the socio-economic, ethnic, educational, and cultural inequality of access and use of digital technologies in society today. Less clear in the literature is as Digital natives and Immigrants age and enter the workforce, how their age will affect their use of technology as a social and information gathering resource (Herring, 2008). Will advances in mobile technologies and age extend the digital divide or will they continue to be technology zealous? Based on data analyzed from wave 6 of the World Values Survey (WVS) a significant difference exists between the generations in the use of different information sources used for information gathering and sharing as they age.
Biocompatible Implanted Dielectric Sensors for Breast Cancer Detection
Authors: Svoboda Noah P. , Sabouni Abas
Published: September 2015

This article describes the development of a method for a biocompatible sensor device for the intent of in-vivo breast tissue dielectric properties measurements. This article focuses on a specific type of sensor that utilizes an LC circuit with an inter-digital capacitor (IDC) with small size and high sensitivity for early stage breast cancer detection. To meet this objective an IDC was optimized in terms of contrast and miniaturized size via simulation techniques. For experimental testing, a scaled-up prototype inter-digital capacitor and spiral square inductor sensor was fabricated, and tested with known media, such as distilled water and glycerol. The results suggest that there is a need for further development, such as fabrication and testing for the biocompatible, miniaturized sensor for breast tissue application.
Fast Data Processing for Large-Scale SOA and Event-Based Systems
Authors: Tilly Marcel , Reiff-Marganiec Stephan
Published: September 2015

The deluge of intelligent objects that are providing continuous access to data and services on one hand and the demand of developers and consumers to handle these data on the other hand require us to think about new communication paradigms and middleware. In hyper-scale systems, such as in the Internet of Things, large scale sensor networks or even mobile networks, one emerging requirement is to process, procure, and provide information with almost zero latency. This work is introducing new concepts for a middleware to enable fast communication by limiting information flow with filtering concepts using policy obligations and combining data processing techniques adopted from complex event processing.
Numerical Simulation of Magnetic Field-Assisted Material Removal in Micro-EDM
Authors: Manesh K.K. , Narayanan Aswathi A.
Published: September 2015

In the present paper, a two dimensional numerical model has been developed using the finite element method (FEM) for predicting the material removal mechanism in micro EDM process in single spark with the assistance of magnetic field. The work piece material selected for the present study is grade 5 titanium material. The model developed by not considering magnetic field, first calculates the temperature distribution in the work piece material using the commercial software ANSYS. The crater shape is developed using the simulated temperature profiles to estimate the volume of material removed in a single spark, by considering the melting point and vaporization temperature. The model has been validated by comparing the theoretical MRR with the experimental results which is already established. The use of magnetic field which can provide an additional Lorentz force in the melt pool could aid in ejection of material from the discharge crater, thereby improving MRR. This concept is established through the coupling of magnetic and structural fields.
Multi-Point Injection Minimum Quantity Lubrication Machining
Authors: Banerjee Nilanjan , Sharma Abhay
Published: September 2015

This paper presents a study on minimum quantity lubrication wherein the metal working fluid is injected individually at multiple points in cutting zone, namely, rake face, back of chip and at flank face. A special attachment is developed for injecting aerosol at all possible combinations of one, two, or three forgoing points of injection. A case study on machining of Ti-6Al-4V showing effect of injection schemes on cutting force and surface roughness is presented. Comparison of multi-point injection with dry and flood cooling indicates reduction in cutting force and surface roughness while using different combinations of fluid injection.
Effects of Heat Treatment on the Tensile Properties of Flow-Formed AA6082 Aluminum Alloy Tube
Authors: Podder Bikramjit , Mondal Chandan , Gopi G. , Ramesh Kumar K.
Published: September 2015

The present study reports the effect of the heat treatment on the tensile properties of the reverse flow-formed AA6082 Aluminum alloy tube. Tensile specimens obtained after each forming pass have been subjected to three different heat-treatment conditions viz., as-flow formed (AFF), as-flow formed followed by artificial aging (170°C/6h) and HT (solutionizing + 170°C/6h) treatments. Characterization of the tensile properties reveals that as-flow formed condition (followed by natural aging) gives the best combination of yield strength, UTS and percentage of elongation. The variations in tensile properties are correlated with microstructure of the materials.
Effect of Heat Treatment on the Microstructure of Gravity Cast and Squeeze Cast Al-Si-Mg Alloy
Authors: Krishnan Arjun Bala , Selvaraj Kavin , Geethakumari Akhil Madhusoodhanan , Manickam Ravi
Published: September 2015

The present work deals with the effect of solutionising heat treatment on the features of Al-7Si-0.3Mg (A356) alloy in terms of microstructural modifications and hardness. The microstructure of sand cast and gravity cast alloys are coarse which results in lower strength compared to the alloys cast using modern casting techniques such as squeeze casting which is used for the fabrication of near-net-shaped castings. The influence of enhanced cooling rate on the hardness and microstructure of the squeeze casting technique has been exploited in the present study. In order to optimise the heat treatment process, the microstructure of the gravity and squeeze cast alloys were compared after solution treatment. The quantitative analysis of the microstructure was carried out using an image analyser attached to the optical microscope. The aspect ratio, particle count and circularity of eutectic silicon and SDAS are measured. The squeeze cast alloy is found to have finer microstructure with enhanced properties compared to the gravity cast alloy.
Effect of Heat Treatment on the Mechanical Properties of Copper-Beryllium Alloy (C17200)
Authors: Alisha S. , Venkateswaran T. , Amruth M. , Chakravarthy P. , Sivakumar D.
Published: September 2015

Owing to high elastic modulus and good strength, copper beryllium alloys are widely used in many engineering applications. The addition of beryllium to copper makes the alloy respond to aging treatment and thus develops very high strength. Conventional heat treatment cycles are available for copper-beryllium to obtain peak ageing hardness condition. Present study has focused on developing a heat treatment cycle to obtain synergetic combination of moderate strength and good toughness for the C17200 copper-beryllium alloy. Ageing curves have been generated for varying temperature and time. Detailed mechanical properties (hardness, impact, tensile) evaluation at room temperature and sub-zero temperatures have been carried out for the selected samples. Modified heat treatment cycle resulted in higher toughness with adequate strength. Optical microscope (OM) and transmission electron microscope (TEM) analysis were carried out to understand the precipitation behavior. Also, measurements of coefficient of thermal expansion (CTE) and thermal conductivity were carried out on the aged samples.
Effect of Post Weld Heat Treatment on Mechanical Properties of 17-4-PH Stainless Steel Welds
Authors: Prabhakar A. Sam , Agilan M. , Venkateswaran T. , Sivakumar D. , Venkatakrishnan P.G.
Published: September 2015

Precipitation hardening stainless steel (17-4-PH) of 3 mm thick sheet was welded by gas tungsten arc welding (GTAW) process using a matching composition filler wire of ER 630. The welds were subjected to various post weld heat treatment (PWHT) cycles viz., H900, H1025 and H1150. Tensile properties (UTS, 0.2% YS, and % EL.), hardness survey across the weld and detailed optical microscopy have been carried-out on as-welded and after different PWHT conditions samples. Results showed that H900 heat treatment condition attained higher mechanical properties than H1025 and H1150.
Thermo Mechanical Fatigue Testing of GTD 111 Superalloy for Use in Gas Turbine Blades
Authors: Patel Brijesh , Kaurase Kalpit P. , Bisen Anil M.
Published: September 2015

Design of Turbo machinery is complex and efficiency is directly related to material performance, material selection is of prime importance. Temperature limitations are the most crucial limiting factors to gas turbine efficiencies. This paper presents the life of GTD 111 applied to gas turbine blade based on LCF and TMF test results. The LCF tests were conducted under various strain ranges based on gas turbine operating conditions. In addition, IP (in-phase) and OP (out of-phase) TMF tests were conducted under various strain ranges. The paper will focus light on above issues and each plays an important role within the Gas Turbine Material literature and ultimately influences on planning and development practices. It is expected that this comprehensive contribution will be very beneficial to everyone involved or interested in Gas Turbines.
Wettability and Bond Shear Strength of Sn-9Zn Lead-Free Solder Alloy Reflowed on Copper Substrate
Authors: Tikale Sanjay , Sona Mrunali , Prabhu K.N.
Published: September 2015

Lead-free solders are environment friendly and are in great demand for microelectronic applications. In the present study, Sn-9Zn lead free solder alloy was solidified on Cu substrate for different reflow times from 10 to 1000s. The influence of reflow time on wetting, formation of intermetallic compounds (IMCs) and bond shear strength was studied using dynamic contact angle analyzer, bond tester and scanning electron microscopy. The results indicate that, the wettability of the solder alloy increased with increase in reflow time. Microstructure study revealed the presence of Cu5Zn8 and CuZn5 IMCs at the interface. The thickness of an IMC increased with increase in the reflow time. The mean thickness of about 11μm for Cu5Zn8 IMC layer was observed for the reflow time of 1000s. The thickness of CuZn5 layer increased up to a reflow time of 100s and decreases thereafter. The bond shear strength increased up to 100s and decreased with increase in reflow time. The decrement in shear strength at higher reflow time is mainly due to excessive thickness of Cu5Zn8 IMC layer and diffusion of Sn from bulk solder towards the substrate. The excessive thick IMC layer exhibited pre micro-cracks led to the brittle failure of bond under the influence of shear stress.
Evaluation of Mechanical Properties of the Rocket Thrust Chamber Material under Flight Conditions
Authors: Anoop C.R. , Bejoy John , Tharian Thomas , Venkitakrishnan P.V.
Published: September 2015

Thrust chamber of rocket engines often operate under conditions of rapid heating environments with temperatures approaching the melting points of the materials involved. Therefore, for the optimum design of rocket engines, it is necessary to obtain the properties of thrust chamber materials under actual operating conditions. The heating rates and loading rates in conventional (laboratory) tensile stress-strain tests, which are intended to evaluate the high temperature tensile properties of the materials, are usually very low compared to that actually encountered in rocket engines. The heating rates in conventional stress-strain tests are of the order of 0.4K per second to 0.5K per second only, whereas the combustion and aerodynamic heating rates in rockets and re-entry vehicles will usually exceed 100K per second. In this context, a very important beginning has been made to experimentally determine the high temperature tensile properties of KC20WN (a cobalt based superalloy) used in earth storable liquid rocket engine thrust chamber under conditions of rapid rates of heating which actually exists during flight. These investigations have shown that the elevated temperature strength of KC20WN depends upon the heating rate (or heating time) and can be considerably higher for rapid-heating conditions than for conventional heating conditions.
Static and Localized Strain Analysis of High Hardened Linear Model Mock-Up Bearing for Fast Breeder Reactor
Authors: Babu S. , Manisekar K.
Published: September 2015

This paper investigates the impact of strain sensitivity on the linear model mock-up bearing (LMMB) using digital image correlation (DIC) technique. This work addresses the lack of norms, standards, reference of elastic/plastic deformation of bearings elements. Towards that, experimental set-up was designed and fabricated with a set of LMMB (AISI4140) with commercially purchased steel balls (AISI52100) to study the raceway relative approach and localized strain rate on steel ball, wherein raceway relative approach is measured using LVDT & screw gauge and results are compared with DIC results. These data are very much useful in design and development of large diameter slewing bearing for fast breeder reactor and also these results can be used to optimize the number of ball, load, and tolerance on bearing.
Development of High Nitrogen Stainless Steel for Cryogenic Applications
Authors: Anil Kumar V. , Gupta R.K. , Karthikeyan M.K. , Gino Prakash F. , Ramkumar P.
Published: September 2015

Austenitic stainless steels are extensively used as structural materials for various aerospace systems. Nitrogen containing stainless steels have special role due to their austenite stabilization tendency down to subzero temperatures, improved strength and resistance to sensitization. Primary processing of nitrogen containing cryogenic grade stainless steel 202 has been carried out through two different melting routes viz. (1). conventional melt route of electric arc furnace (EAF) melting followed by vacuum oxygen decarburization (VOD) & vacuum degassing (VD) and other one through (2). vacuum induction melting (VIM) followed by ESR. Chemical analysis and macrostructure analysis was carried out on the samples drawn from these billets. Homogenization and thermomechanical processing parameters were selected and the same were followed for the ingots made through both the melt routes. Mechanical properties evaluation (including tensile properties at subzero temperature of 77K) and micro structure characterization of the products realised from all the two melt routes were carried out.
It is observed that, both the melt routes could result in achieving the required aerospace quality of alloy with respect to the chemical composition, metallurgical and mechanical properties. This paper confirms that any of the melt routes studied herein can be adopted according to availability of the facilities. The process development and characterization of the steels processed by conventional EAF+ VD & VOD and VIM+ESR melt routes is presented in this paper.
Effect of Microalloying Elements on Mechanical Properties in the High Strength Low Alloy Steel
Authors: Mandal P.K. , Kant Ravi
Published: September 2015

The effect of microalloying elements in Ti-Nb-V containing high strength low alloy (HSLA) steel has been investigated in the present study. The addition of low alloying elements (such as Ti, Nb and V) and distinct heating treatment processes has been used to improve the mechanical properties of HSLA steel. The effect on the microstructure and mechanical properties of normalizing treatment (at 950°C) of as forged steel has been investigated. The microstructural characterization of microalloyed HSLA steel is carried out by using different techniques such as optical microscopy, scanning electron microscopy (SEM) etc. The hardness, tensile testing and Charpy V notch impact tests are performed to study the mechanical behaviour of the alloy. It has been concluded that the precipitation strengthening mechanism for the improvement of impact toughness due to secondary precipitates such as TiN, Ti(C, N), VN etc.
Experimental Investigation and Micro-Structure Study of Interface of Explosive Welded SS304 and AA6061 Plates
Authors: Upadhyay Abhishek , Sherpa Bir Bahadur , Kumar Sandeep , Srivastav Niraj , Dinesh Kumar Pal , Agarwal Arun
Published: September 2015

The explosive welding is a non-conventional technique gaining popularity due to its ability to join dissimilar metals. The technique is very successful in achieving area joining by using the controlled energy of explosives which creates a metallurgical bond between two similar or dissimilar materials. This paper explains the technique of explosive welding for joining SS304 and AA6061 using pure aluminum (2 mm) as an interlayer. The joining was done in two stages. The explosive used is a mixture of Trimonite and salt having velocity of detonation (VOD) in the range of 1500-1600 m/sec. Ultrasonic testing showed good bonding over more than 80%. Micro-hardness variations as compared to parent materials have been evaluated along with microstructure study done to analyze the interface characteristics. SEM/EDS also have been used to check the presence of any possible brittle phases. Both the interfaces are found to be laminar, continuous, uniform and free from micro-cracks.
Solder Joint Reliability of Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys Solidified on Copper Substrates with Different Surface Roughnesses
Authors: Satyanarayan  , Prabhu K.N.
Published: September 2015

In the present work, the bond strength of Sn-0.7Cu, Sn-0.3Ag-0.7Cu, Sn-2.5Ag-0.5Cu and Sn-3Ag-0.5Cu lead free solders solidified on Cu substrates was experimentally determined. The bond shear test was used to assess the integrity of Sn–Cu and Sn–Ag–Cu lead-free solder alloy drops solidified on smooth and rough Cu substrate surfaces. The increase in the surface roughness of Cu substrates improved the wettability of solders. The wettability was not affected by the Ag content of solders. Solder bonds on smooth surfaces yielded higher shear strength compared to rough surfaces. Fractured surfaces revealed the occurrence of ductile mode of failure on smooth Cu surfaces and a transition ridge on rough Cu surfaces. Though rough Cu substrate improved the wettability of solder alloys, solder bonds were sheared at a lower force leading to decreased shear energy density compared to the smooth Cu surface. A smooth surface finish and the presence of minor amounts of Ag in the alloy improved the integrity of the solder joint. Smoother surface is preferable as it favors failure in the solder matrix.
Structure and Hardness of Friction Stir Welds out of High-Strength Non-Heat Hardenable Cast and Wrought Aluminum Alloys
Authors: Ilyasov Rafis , Predko Pavel , Avtokratova Elena , Konkevich Valentin , Sitdikov Oleg , Markushev Michael
Published: September 2015

Optical and electron microscopy analyses of friction stir welds out of commercial cast and deformable Al-Mg-x alloys have shown the typical onion-like macrostructure consisting of alternating layers of both the alloys. Maximum microhardness of ~120 Hv has been found in the center of the welds owing to strong grain refinement and exceeding values for both the initial alloys. Mechanisms of structure transformations, as well as hardness changes in the nugget and thermo-mechanically affected zones are discussed.
Development of Titanium Alloy Hemispherical Forging for Pressure Vessel of Launch Vehicle
Authors: Gupta Rohit Kumar , Anil Kumar V. , Chauthai Abhay R. , Ramkumar P.
Published: September 2015

Titanium alloy Ti6Al4V is used for manufacturing pressure vessels of launch vehicle in view of its excellent corrosion resistance and fabrication characteristics. This material also offers advantage of good strength to weight ratio necessary for space application. This paper describes the experience gained in the technology development of hemispherical forgings of titanium alloy Ti6Al4V. To achieve α-β microstructure and mechanical properties in the final product, hot working of the alloy from the stage of forging of cast ingots to finish working was carried out in the (α-β) region. The manufacturing parameters are established through state-of-the-art technology and capabilities. Process technology for processing of the hemispherical dome has been established and the same has been presented here.
Effect of Cooling Rate on Mechanical and Microstructural Characterization of Friction Stir Welded 316 L Austenitic Stainless Steel Joints
Authors: Shashi Kumar S. , Murugan N. , Ramachandran K.K.
Published: September 2015

The present investigation is carried out to investigate on mechanical and metallurgical properties of Friction stir (FS) / Underwater Friction stir (UFS) welded 3 mm thick AISI 316 L stainless steel joints. Experiments were carried out at a tool rotational speed of 700 rpm, welding speed of 45 mm/min and axial force of 12 kN. Defect free joints were confirmed by visual inspection. A marginal rise of about 4.5 % increase in the joint strength is achieved in water cooling than by gas cooling technique. Reduced peak temperature in water cooled joint led to better grain refinement in the weld nugget enhancing FSW tool life. No sign of secondary phase precipitation was observed in the weld joints which was confirmed by Energy Dispersive Spectroscopy (EDS) spectrums and micro etchants like Groesbeck and modified Murakami reagents in the weld nugget.
Microstructure and Superplasticity of an Al-Mg-Sc-Zr Alloy Processed by ECAP and Subsequent Cold Rolling
Authors: Avtokratova Elena , Sitdikov Oleg , Mukhametdinova Oksana , Markushev Michael , Narayana Murty S.V.S. , Prasad M.J.N.V. , Kashyap Bhagwati Prasad
Published: September 2015

The feasibility has been demonstrated for achieving high-strain-rate superplasticity with elongations beyond 2000% in Al-Mg-Sc-Zr alloy with the partially recrystallized structure, produced by warm equal-channel angular pressing to strain of e~3 only. Subsequent alloy ambient temperature rolling up to e~1.6 enhanced the superplastic elongations and moved the optimum of superplasticity toward the higher strain rates.
Study of Microstructure and Wear Behavior of T6 Heat Treated as Cast Al-25Mg2Si-2Cu Alloy
Authors: Sondur D.G. , Goudar D.M. , Mallapur D.G. , Rudrakshi G.B.
Published: September 2015

In the present investigation, microstructural characteristics and dry sliding wear behaviour of T6 heat treated conventionally cast Al-25Mg2Si-2Cu alloy have been discussed. The as cast alloy was subjected to solutionizing at 500°C for 5h and isothermal aging treatment at 190°C for different aging times. The micro structural characterization was studied using Scanning Electron Microscope with EDS analysis. The microstructure of as cast alloy consists of intermetallics of coarse block like sharp edged β-(Mg2Si), θ-(Al2Cu) and Q-(Al-Mg-Cu-Si) in the form of Chinese scripts and needles distributed randomly in the Al-matrix. The microstructure of heat treated alloy shows spheroidization of β phase and fine precipitation of θ-(Al2Cu) and Q phases. The dry sliding wear test was carried out using pin-on-disc machine. Age hardened alloy exhibits high wear resistance and minimum coefficient of friction over the entire range of applied loads and sliding velocities. Furthermore, high wear resistance was observed in the under aged condition compared to over ageing conditions.
Thermal Expansion Behaviour of Inconel-690 by In Situ High Temperature X-Ray Diffraction
Authors: Ramachandran D. , Kirubaharan A.M. Kamalan , Rabel Arul Maximus , Kuppusami P.
Published: September 2015

Ni-Cr-Fe based alloy Inconel 690 is widely used in power plant, marine, chemical and nuclear applications due to its excellent mechanical properties, resistance to thermal creep deformation, good thermal stability and resistance to corrosive and oxidizing environments. In order to study the microstructure of the alloy and the precipitates formation during thermal exposure, the alloy was subjected to in-situ high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1273K. Results of high temperature XRD patterns show (111), (200), (220) and (311) reflections confirming the stability of fcc structure in the temperature of investigation. With increase in the temperature, a shift in peak positions towards lower 2θ values due to lattice expansion was noticed. The average thermal expansion coefficient (TEC) of the alloy increased from 1.33 x 10-5 K-1 to 1.53 x 10-5 K-1 in the temperature range 298-1273 K. Scanning electron microscopy indicates austenitic grains of sizes in the range 100-150μm and chromium carbide precipitate at grain boundaries after the HT-XRD heat treatment.
Effect of Sb, Sn and Pb Additions on the Microstructure and Mechanical Properties of AZ91 Alloy
Authors: Boby Arun , Srinivasan Amirthalingam , Pillai Uma Thanu Subramonia , Pai Bellambettu Chandrasekhara
Published: September 2015

This article presents the effect of individual addition of Sb, Sn and Pb on the precipitation sequence at room as well as high temperature tensile properties of AZ91 alloy. The results show grain refinement, formation of Mg3Sb2 and Mg2Sn phases when Sb and Sn are added to AZ91 alloy. Lamellar precipitate is significantly suppressed while Pb added. Improved room and high temperature tensile properties are observed in Sb and Sn addition. Maximum tensile properties are noticed with AZ91 alloy having 0.5 wt.% Sb addition.
Processing and Characterization of Inconel 625 Nickel Base Superalloy
Authors: Gupta R.K. , Anil Kumar V. , Gururaja U.V. , Shivaram B.R.N.V. , Maruti Prasad Y. , Ramkumar P. , Chakravarthi K.V.A. , Sarkar P.
Published: September 2015

Nickel-based superalloy Inconel 625 is widely used in aeronautical, aerospace, chemical, petrochemical and marine applications due to its good mechanical properties, weldability and resistance to high temperature corrosion on prolonged exposure to aggressive environments. It is a solid solution strengthened medium strength superalloy, which contains chromium, molybdenum and niobium as alloying additions.
Considering the chemistry and specification requirements of the alloy, it was processed through vacuum induction melting (VIM) process followed by electro slag remelting (ESR) route to obtain alloy with controlled gas and inclusion contents. Homogenisation cycle was selected and was carried out at 1170°C temperature to obtain uniformity in chemistry and microstructure. Chemical homogeneity was confirmed through analysis of samples from top, middle and bottom of the secondary ESR ingot. Hot working range was decided considering the flowability of superalloy and the same was carried out under close monitoring of temperature and with specified amount of reduction per stroke. Intermediate reheating and reduction during forging was noted to be an important aspect so to avoid cracking during forging. Processing parameters were established to obtain forgings of different thicknesses with sound ultrasonic quality. Microstructure analysis revealed single phase austenitic grain structure with ASTM grain size no. 4-7, confirming that material has undergone sufficient amount of mechanical working. Mechanical testing was carried out and the mechanical properties were found to be meeting the requirement. Present paper provides details of melting process selection, thermomechanical processing and characterization of the superalloy to achieve the targeted mechanical properties.
Microstructure Development in Cold-Rolled Al-Mg-Sc-Zr Alloy under Furnace and Short Electric Pulse Annealing
Authors: Ilyasov Rafis , Sitdikov Oleg , Avtokratova Elena , Markushev Michael
Published: September 2015

Effects of furnace and short electric pulses (SEP) annealing with current density of ~104 A/mm2 on the microstructure of the cold-rolled 01570c aluminum alloy, containing high densities of Al3(Sc,Zr) dispersoids, were investigated. The high potential of the SEP annealing to process fine-grained sheets from aluminum alloys with high additions of transition metals has been shown.
Characterization of Different Adhesives for Bonding Thermal Protection System (TPS) on a Space Crew Capsule
Authors: Swain Digendranath , Karthigai Selvan S. , Rajesh Kumar G. , Abhilas J.O. , Thomas Binu P. , Philip Jeby
Published: September 2015

This paper demonstrates a unique application of DIC wherein the structural performance and structural integrity have been evaluated together almost in real-time. The results obtained from the ground level tests, simulating the bonding between the TPS to the base structure of a space crew module, are reported to find the adequacy of two different adhesives prior to actual bonding. The test objective was to characterize the adhesives based on the structural performance (deflection and strain behavior) of the TPS and conduct health monitoring in real-time (i.e. abort the test whenever the TPS fails). The dual objective could be met using DIC in a full-field and non-contact manner, which was essential due to the limitations of the contacting type measurements.
Experimental Study on the Effect of Mechanical Stirring in Semisolid Processing of Aluminum Alloys at Thixo-Temperatures
Authors: Kishore M.V. , Hanumantha Rao D. , Manzoor Hussain Mohammed
Published: September 2015

Semisolid metal processing (SSMP) is a relatively new technology for production of near net shaped components. This process is carried out at a temperature range between its liquidus and solidus temperature. At thixo-temperatures, the metal exists as a mixture of solid and liquid phases in the slurry form. Thixotropy is a time-dependent shear thinning property where the metal is thick at static conditions but will flow when subjected to shear stress. The present research work focuses to identify the process parameters in SSMP. A mechanical stirring process was employed to obtain the desired microstructure required for SSMP. Process parameters such as stirring time and stirring speed were considered. The effect of addition of grain refiner to the molten alloy on the microstructure was also studied.
Hot Pressing and Characterization of ZrB2-SiC-MoSi2 Composite
Authors: Venkateswaran T. , Agilan M. , Sivakumar D. , Pant Bhanu
Published: September 2015

Transition metal diborides, especially zirconium and hafnium diboride are potential ceramic material for ultra high temperature applications above 1800°C. These borides are characterized by high melting point, formation of high melting point oxides, good oxidation resistance and excellent thermo-mechanical properties. In this present exploration, zirconium diboride (ZrB2) has been selected for its moderate density (6.09 gm/cc) and better oxidation resistance compared to high density hafnium diboride (11.2 gm/cc). The developed ZrB2 composite in the present study contains 10 wt. % SiC and 10 wt. % MoSi2 as sintering additives. SiC and MoSi2 were added to improve the thermal shock resistance and sinterability of the ultra high temperature ceramics (UHTCs). Vacuum hot pressing was carried out at 1800°C for a holding period of 30 minutes and applied pressure of 30 MPa. Attractive feature of this ZrB2 composite is good machinability due to better electrical conductivity and complicated shapes can be realized easily through electro discharge machining (EDM) process. Detailed XRD phase analysis and microstructural investigation of the polished and fractured composites was carried out using SEM. Mechanical and thermal properties tests have been carried out for the optimized ZrB2 composite material.
Alumina Powder Dispersions in Molten Urea for the Preparation of Macroporous Alumina Ceramics by Freeze Casting
Authors: Vijayan Sujith , Narasimman Rajaram , Prabhakaran Kuttan
Published: September 2015

Alumina powder dispersions in molten urea medium were prepared using ammonium poly (acrylate) dispersant. The dispersant concentration for achieving very good dispersion of the powder was optimized through rheological measurements. The optimum dispersant concentration for alumina powder dispersion in molten urea (1.25 wt.% of alumina) is higher than that required in aqueous medium (0.35 wt%). The dispersions with alumina loading as high as 55 vol.% having low viscosity could be achieved in molten urea medium at 135 °C. The viscosity and yield stress of the alumina powder dispersions in molten urea is low enough for casting.
Processing of Porous Ceramics Using Aluminium Derived Binders and Sacrificial Porogen Leaching Method
Authors: Resmi V.G. , Sree Manu K.M , Deepa J.P. , Lakshmi V. , Rajan T.P.D. , Pavithran C. , Pai B.C.
Published: September 2015

Porous ceramics was successfully fabricated by a sacrificial porogen leaching method using in-situ synthesised aluminium based binders by reaction bonding at low sintering temperatures of 600-1000°C. Porous ceramics with porosity in the range of 27 to 65% were obtained by leaching technique. Interconnected bimodal pores were produced by both stacking of starting particles and leach out of salt. During sintering, the aluminium binder experienced metal to ceramic transformations and act as good binder.
Computer Simulation of Low Pressure Casting Process Using Flow 3DTM
Authors: Viswanath Abhilash , Sivaraman Savithri , Pillai Uma Thanu Subramonia
Published: September 2015

The calibre of low pressure casting (LPC) process in meeting the demands for improved quality and aesthetics for thin walled components has been widely accepted in casting industries. In spite of numerous advantages, the process is still being used very less to its potential. The basic reason has been the difficulty in determining various processing parameters associated which can be circumvented effectively by numerical simulation. In the present work, the commercial CFD code FLOW 3DTM, has been used to simulate the mould filling and solidification during the LPC process.
Effects of Heat Generation on Microstructure and Hardness of Cu/SiCp Surface Composite Processed by Friction Stir Processing
Authors: Cartigueyen S. , Mahadevan K.
Published: September 2015

In this investigation, copper (Cu) based surface composites reinforced with silicon carbide (SiC) particles were fabricated using friction stir processing (FSP) route. FSP was carried out considering three-factor three-level Box-Behnken design to study the effects of process parameters on peak temperature and hardness of Cu/SiCp surface composites. Microstructural evaluation using optical microscope (OM) revealed that SiCp were uniformly distributed and well – bonded with copper matrix at an adequate heat input conditions. The microhardness of the surface composites were remarkably enhanced than that of base metal. Regression models have been developed for predicting peak temperature and microhardness of processed surface composites and the same were in good agreement with experimental results.
Quantitative Feeder Design for Metal Castings
Authors: Madhan Kumar P. , Jacob Elizabeth , Savithri S. , Suneeth G.S.
Published: September 2015

Casting simulation packages are used to check a design for its castability. A better starting design should need fewer simulation cycles to arrive at a defect-free component thus cutting computation and manpower costs. Quantitative design of the feeding system is done by an analysis of the solidification pattern of the 3D model of the cast component. A clustering algorithm uses the solidification time/temperature data from the simulation to divide the casting into 3D feeding sections. The sections are created by following hotspots surrounded by areas of decreasing solidification time. Feeders are built by the feeder design module of AutoCAST casting design software. The initial simulation as well as the efficacy of the rigging is tested through the advanced simulation module FLOW+ of AutoCAST X. An industrial case study illustrates the software pipeline in a virtual foundry trial.
Studies on High Temperature Evolution of Polymer Derived Nano SiC Ceramics
Authors: Sasikala T.S. , Devapal Deepa
Published: September 2015

Borosiloxane oligomers, which give ceramic residue in the range of 70-78% (at 900°C) in inert atmosphere, were synthesized through the condensation of boric acid with allyltriethoxysilane without using any catalyst. The effect of concentration of the reactants on the processibility, yield and thermal stability of the product obtained was studied. All oligomers were pyrolysed at 900°C followed by ceramic conversion after sintering at 1500°C and 1650°C in inert atmosphere and were characterized by XRD and spectroscopic techniques. Mixture of α and β-SiC are formed after sintering the samples at 1650°C for 3 hours in inert atmosphere.
Characterization of Metal-PCMs for Thermal Energy Storage Applications
Authors: Sudheer R. , Prabhu K.N.
Published: September 2015

In recent years phase change materials have emerged to be ideal energy storage materials for their higher energy density over sensible heat storing materials. Use of phase change materials (PCM) have been successfully implemented at lower temperature applications with various organic compounds. On the other hand, high temperature applications have been solely dominated by various salts, their eutectics and mixtures as phase change materials. This work discusses the suitability of metals and alloys for thermal energy storage applications as the phase change material. Metals offer superior thermal conductivities with considerable energy density compared to salts. Here, two alloys namely, Sn-0.3Ag-0.7Cu (SAC) solidifying over 212-224°C and ZA8 (Zn-8%Al) solidifying over 378-405°C have been studied. Thermal analysis of PCMs using Computer Aided Cooling Curve Analysis (CA-CCA) and DSC technique were performed to predict the solidification path. In addition to this, Newtonian technique was employed to estimate the latent heat of fusion for these phase change materials. Cooling rate curves and Fraction Solid curves offered a better insight into their ability to receive and discharge heat over the concerned temperature range.
A Novel Process for the Preparation of a Nickel Foam
Authors: Mehatab Nabi S. , Sagar Babu N. , Vijayan Sujith , Prabhakaran Kuttan
Published: September 2015

A novel process for the preparation of a nickel foam from nickel oxide has been studied. The solid organic foam prepared by the thermo-foaming of a nickel oxide powder dispersion in molten sucrose is heat treated at the 1000 °C in an inert atmosphere to produce the nickel foam. The nickel foam produced has interconnected cellular structure with porosity ~ 94%.
A Comparative Analysis of Orientation on the Shape Memory Effect of Fabric Reinforced Shape Memory Polymer Composites
Authors: Mohanakrishnan D. , Sureshkumar M.
Published: September 2015

Shape memory polymer composites (SMPC) are a new kind of smart materials where many researches have been carried out. In SMPC, shape memory polymers serves as a matrix material and particles or fibers act as reinforcements. As structural applications demand structures to withstand load and stiffness, particles reinforced SMPC does not serve for it. Therefore fiber/fabric reinforced SMPC used widely for such applications. SMPC’S changes its shape during a typical thermo-mechanical cycle and retracts to its original shape upon external stimulus (temperature). Molecular mechanism is the driving force of these SMP’s. SMP consists of 1.molecular switches and 2. netpoints. This project deals with Epoxy shape memory resin (Matrix material) and fabrics such as Glass, Kevlar and Carbon (Reinforcements).A Comparative analysis was carried out to find which combination gives the best results by bend test. Different orientations were tried for bidirectional fabrics such as (0/90)3, (0/45)3, ((0/90)/(±45)/(0/90)) specimens. Finally it was concluded that Carbon fabric which has the orientation of (0/90/±45/0/90) gives better shape memory performance.
Computer Simulation of Centrifugal Casting Process Using FLOW-3D
Authors: Aneesh Kumar J. , Krishnakumar K. , Savithri S.
Published: September 2015

Centrifugal casting process is one of the potential manufacturing techniques used for producing functionally graded materials viz., composite materials or metallic materials which have high differences of density among constituents. In this process, the fluid flow plays a major role and understanding the complex flow process is a must for the production of defect-free castings. Since the mold spins at a high velocity and the mold wall being opaque, it is impossible to visualise the flow patterns in real time. Hence, in the present work, the commercial CFD code FLOW-3DTM, has been used to simulate the mold filling sequence for a simple hollow cylindrical casting during vertical centrifugal casting process. Effect of various spinning velocities on the fill pattern during vertical centrifugal casting process is being investigated.
Kalonji Seed Extract Mediated Green Synthesis of ZnO Nanopowders: Photocatalytic, Antibacterial and Antioxidant Activities
Authors: Kavyashree D. , Anandakumari R. , Nagabhushana H. , Basavaraj R.B. , Raja Naik H. , Lingaraju K.
Published: September 2015

ZnO nanoparticles (NPs) with different morphologies were synthesized via green route using Kalonji seed extract (KSE) as fuel. The formation of ZnO nanostructures (NSs) were characterized by XRD, SEM, UV-vis. The influence of KSE concentration on the morphology, UV visible absorption, and photocatalytic activity of ZnO NPs were investigated. The various morphologies of ZnO NPs probed for the photocatalytic degradation of Methylene blue (MB). The enhanced photocatalytic activities of ZnO nanoflower was attributed to small crystallite size, more surface defects, wide band gap and capability for reducing the electron-hole pair recombination. In addition, ZnO NPs showed significant antibacterial activity against Gram –ve bacterial strain Klebsiella aerogenes when compared to Gram +ve bacterial strain Staphylococcus aureus.
Highly Active TiO2-MoS2 Composite for Visible Light Photocatalytic Applications
Authors: Mohamed Mukthar Ali S.M.Y. , Sandhya K.Y.
Published: September 2015

Efficient visible light active TiO2-Molybdenum sulphide (TiO2-MoS2) composites were prepared by solvothermal methodfrom titanium isopropoxide and commercial MoS2 using N-methyl 2-pyrrolidone (NMP) and isopropanol (IPA) solvent mixture. Extended absorption band edge and enhanced visible light absorbance are supplemented intothe TiO2-MoS2 composites by this method. While TiO2 shows ~48% visible light photodegradation of rhodamine B (RhB) the TiO2-MoS2(0.24) exhibits~74% of degradation. In addition to the visible light enhancement, very high surface area and reduced charge transfer resistance at the interfaces are attributed to the enhanced activity of the composite.
Influence of Reactivity of Sheath Metals on the Superconducting Properties of NdFeAsO0.6F0.4 Wires
Authors: Pillai Mohan Aswathy , Jayakumari Babu Anooja , Varghese Neson , Upendran Syamaprasad
Published: September 2015

The influence of reactivity of different sheath metals such as Ag, Fe, Cu, Ni and SS on the superconducting properties of NdFeAsO0.6F0.4 wires has been investigated. The observed structural and superconducting properties of the metal sheathed wires conclude that among the five candidates Ag and Fe are technically compatible to be used as sheath materials in terms of reactivity. However, the best superconducting properties such as TC and transport JC were exhibited by Ag sheathed NdFeAsO0.6F0.4 wires.