020881   Chawla A;Mukherjee S (Transportation Research and Injury Prevention Program, Indian Institute of Technology Delhi, New Delhi-110 016, Email: achawla@mech.iitd.ernet.in) : Motoecycle safety device investigation: a case study on airbags. Sadhana 2007, 32(4), 427-43.

The standard for assessing the effectiveness of safety measures for motorcycle riders defined in ISO 13232 is unique and it incorporates evaluation by computer simulation supplemented by full-scale crash tests. Describes the process of using FE (Finite Element) simulations to investigate safety options for motorcycle riders. The experience of developing finite element models acceptable as per ISO 13232 standards has been described. The variation in dummy head accelerations on impact with inflating airbags has been studied in an environment acceptable as per ISO 13232 standards. Based on the simulations, it may be concluded that inflating airbags in motorcycles do not pose a significant injury threat.

16 illus, 1 table, 41 ref

020880   Chatterji S;Rao C S;Nagsarkar T K (NITTTR, , Chandigarh) : Fuzzy logic based thyristor controlled dynamic brake. J Instn Engrs-Pt EL 2008, 88(Mar), 22-7.

Thyristor controlled dynamic brake (TCDB)has been one of the effective controllers for improving transient stability of power systems. In the present paper Multi-layer Fuzzy Logic Technique has been applied to control the switching of TCDB used for enhancing transient stability of power system. Sim illation results of transient stability studies employing Multi-layer Fuzzy Logic Switching control of TCDB for a single - machine infinite bus system and a multi - machine system are presented in this paper. Simulation results for the proposed device - Fuzzy Logic based Thyristor Controlled Dynamic Brake (FLTCDB) indicate that this scheme provides better switching control strategy as compared to the conventional TCDB for identical working conditions.

5 illus, 6 tables, 11 ref

020879   Barshilia H C;Rajam K S (Surface Engineering Div, National Aerospace Laboratories, Bangalore-560 017, Email: harish@css.nal.res.in) : Performance evaluation of reactive direct current unbalanced magnetron sputter deposited nanostructured TiN coated high-speed steel drill bits. Bull Mater Sci 2007, 30(6), 607-14.

The stainless steels, in general, are considered to be difficult-to-machine materials. In order to machine these materials the surface of the tool is generally coated with physical vapour deposition (PVD) hard coatings such as titanium nitride (TiN), titanium aluminum nitride (TiAlN), etc. The adhesion is of vital importance for the performance of tools coated with PVD coatings. Proper surface treatments (in situ and ex situ) are required to achieve highly adherent PVD coatings on tools. We have deposited nanostructured TiN coatings on high-speed steel (HSS) drill bits and mild steel substrates using an indigenously built semi-industrial four-cathode reactive direct current (d.c.) unbalanced magnetron sputtering system. Various treatments have been given to the substrates for improved adhesion of the TiN coatings. The process parameters have been optimized to achieve highly adherent thick good quality TiN coatings. These coatings have been characterized using X-ray diffraction, nanoindentation and atomic force microscopy techniques. The performance of the coated HSS drill bits is evaluated by drilling a 13 mm thick 304 stainless steel plate under wet conditions. The results show significant improvement in the performance of the TiN coated HSS drill bits.

10 illus, 2 tables, 15 ref

020878   Ballal M S;Khan Z J;Sonolikar R L (Maharashtra State Electricity Transmission Company Limited, Bhusawal, Dist: Jalgaon) : ANN approach for the incipient faults detection in single phase induction motor. J Instn Engrs-Pt EL 2008, 88(Mar), 10-5.

Emerging technology of artificial neural networks has successfully been applied in a variety of areas such as, fault detection, control, signal processing, and many others applications. This paper presents an artificial neural network (ANN) methodology for the detection of incipient faults in induction motor. The ANN based detector a voids the problems associated with traditional incipient fault detection schemes by employing readily available information, such as, motor intake current, rotor speed, and stator winding temperature. The two types of ANN based incipient fault detectors are developed, i.e, conventional and higher order ANN fault detector. The results of the evaluation indicates that the higher order ANN based incipient faults detector provides more accurate results.

5 illus, 2 tables, 15 ref

020877   Arya L D;Koshti A (Electrical Dep, Engineering, SGSITS, Indore, Madhay Pradesh) : Static load models using artificial neural networks. J Instn Engrs-Pt EL 2008, 88(Mar), 28-3.

Describes load models based on the particular form decided by the type of artificial neural network used. Load model identification has been performed using functional link network and back propagation rule based feed forward network. A case study has also been reported. Load models as obtained by FLN and BPANN has been compared with exponent type load model as obtained by leas square estimation method.

2 illus, 3 tables, 12 ref

020876   Aliev M K;Saboor A (Faculty of Engineering, Materials Engineering Dep, Tarbiat Modares Univ, P.O. Box 14115-143 Tehran, Iran, Email: sabour02@yahoo.com) : Pulsed nanocrystalline plasma electrolytic boriding as a novel method for corrosion protection of CP-Ti (Part 1: Different frequency and duty cycle). Bull Mater Sci 2007, 30(6), 601-5.

Potentiodynamic polarization and electrochemical impedance spectroscopy were employed to test borided CP-Ti, treated by a relatively new method called pulsed plasma electrolytic boriding. The results show excellent corrosion resistance for modified CP-Ti. The effect of frequency and duty cycle of pulsed current was investigated. It was found that pulse frequency and duty cycle affect the size and porosity of nanocrystalline borides and by controlling these effective parameters, surface modification can render the CP-Ti material extremely corrosion resistant as a biomaterial.

7 illus, 2 tables, 11 ref

020875   Abbas Ahmadi (Chemistry Dep, Islamic Azad Univ, Karaj Branch, Karaj, Iran, Email: abbas_ahmady_3957@yahoo.com) : Effect of quinizarin dye on the aluminum corrosion by Pseudomonas aeruginosa. Asian J Chem 2007, 19(2), 975-80.

Effect of an organic dye (quinizarin), on resistance of aluminum plates to MIC was studied. An overnight culture of Pseudomonas aeruginosa in a chemically defined medium was inoculated in each test tube containing artificial seawater plus various prepared aluminum plates and investigated by various electrochemically methods consisting: Cyclic and AC voltammetry and scanning electron microscopy. The results obtained showed that the growth of the P. aeruginosa in the medium containing quinizarin dye had not significantly difference with that of the control medium. Scanning electron microscopy micrographs and electrochemical impedance measurements showed that the amounts of the bacteria on the surface of coloured plate were more than that of on uncoloured plates, however, the corrosion rate in the later plates was more than coloured plates. It seems that quinizarin dye is useful for inhibiting of aerobic corrosion of aluminum materials by P. aeruginosa.

4 illus, 13 ref

019789   Vijaykumar M (NO, Defence Metallurgical Research Laboratory, Kanchanbagh-500 058, Email: muvikanale@rediffmail.com ) : Process technology for making sintered ceramic cores. Metals Mater Process 2007, 19(1-4), 225-40.

Sintered ceramic cores are used for introducing cooling channels during casting of equiaxed, directionally solidified or single crystal superalloy components used in gas turbine engines. Process technology for making these cores was identified as one of the critical technologies in the Gas Turbine Engine Development project, and a major effort was mounted in the early 1990s by DMRL, Hyderabad to indigenize this technology. After examining the various options available, a generic ceramic powder shaping process based on Ceramic Injection Moulding technique was chosen. This paper provides an overview of the work in DMRL on the total process technology for making the cores including the development of processing methodologies and equipment facilities needed for the purpose.

18 illus, 2 tables, 19 ref

019788   Venugopal Rao A;Krishna Kumar R;Mohandas T; Madhusudhan Reddy G (NO, Defence Metallurgical Research Laboratory, PO: Kanchanbagh, Hyderabad-500 058, Email: venu_hyderabad@hotmail.com) : Some critical issues in the finite element analysis of friction welding. Metals Mater Process 2007, 19(1-4), 127-36.

Friction welding is an important solid-state joining process for similar and dissimilar metallic materials in the automotive industry for the manufacture of parts such as drive shafts and bimetallic valves. It is also used in the fabrication of critical aeroengine components such as compressor discs. Experimental measurement of the process variables is very difficult due to the rapid heating-rates and complex metal-flow patterns caused by the high strain-rates in friction welding. Hence, Computer-aided-analysis techniques such as Finite Element (FE) analysis are the only techniques presently available to understand the heat generation and temperature-deformation patterns. This paper highlights the methodology followed and the typical issues involved in the numerical analysis of the process using ABAQUS FEM software. The correlation of the FEM output with experimental observations on welding of stainless steel AISI 304 rods is also discussed.

5 illus, 10 ref

019787   Venkateswaran N;Radhakrishnan S R; Sathyanarayanan P L (NO, Combat Vehicles Research & Devfelopment Centre, Chennai-600 054) : Performance improvement of cooling system in T72 bridge layer tank. Def Sci J 2008, 58(1), 77-85.

Modern armoured fighting vehicles (AFVs) are provided with compact and efficient cooling systems. Any increase in volume warrants the protection which, in turn, increases the weight and size of the vehicle. In a combat vehicle, space is at premium. The AFVs (battle tanks) used by the Indian Army were found to be overheating when operated in deserts at very high-ambient temperatures of 323K. (50 °C). This imposes severe restrictions in operating the tanks for prolonged time in deserts. The various subsystems of the cooling pack were investigated scientifically and an optimised solution was arrived at, implemented and proved successful in the subsequent desert trials. This paper deals with the details of investigations, modifications, and the results of studies on bridge layer tank (BLT-T72).

8 illus, 6 ref

019786   Venkateswara Rao N;Bansal B S;Ankalu K;Dutta A;Srinivas M;Muraleedharan K;Balamuralikrishnan R;Malakondaiah G (NO, Defence Metallurigical Research Laboratory, Kanchanbagh, Hyderabed-500 058, Email: bmk_pgh@yahoo.com) : Continuous casting and controlled rolling of a micro-alloyed hsla steel DMR-249A. Metals Mater Process 2007, 19(1-4), 261-71.

To make DMR-249A steel cost effective, continuous casting followed by controlled rolling route has been developed in association with SAIL. Through extensive laboratory trials, an optimum controlled rolling cycle adaptable to Indian steel plants was worked out. Plates of microalloyed HSLA steel, DMR-249A, with thickness varying from 8mm to 18mm have been processed through BSP, SAIL by controlled rolling of continuously cast slabs. Samples from these plates were subjected to microstructural and mechanical properties evaluation. While plates of 8, 10 and 12mm thickness were found to possess the required yield strength as well as sub-zero impact toughness, the thicker plates (14, 16 and 18mm thickness) exhibited a large scatter in the sub-zero impact toughness. Careful analysis of the grain size distribution in the samples revealed interesting differences between the thinner (8, 10 and 12mm) and the thicker (14, 16 and 18mm thickness) plates. The observed scatter in the sub-zero impact toughness values for the thicker plates might be attributed to these differences. Through Ca-Si treatment and further improvements in the rolling practice, the acceptable product range in the second heat could be extended to plates of thickness up to16mm. Thus, the size limitation of 9.5m (L) x 2.5m (W) imposed by the existing heat treatment facility in the country has been overcome for plates up to 16mm thickness. Bulk production of sheets and plates of DMR-249A steel has since been stabilized at the steel plants of SAIL and large quantities have been supplied to shipyards.

9 illus, 1 tables, 5 ref

019785   Venkataraman B;Das D K;Murthy J K N;Alam M Z (NO, Defence Metallurgical Research Laborataory, Kanchanbagh, P.O, Hyderabad-500 058, Email: b_venkata_raman@yahoo.co.in) : Tribology and oxidation resistant coatings for aero-engine applications. Metals Mater Process 2007, 19(1-4), 347-62.

Surface modification in an aero-engine is inevitable considering severe and hostile environment causing surface damages such as wear, erosion and oxidation. Over the years, DMRL has been involved in addressing various aspects related to coatings for tribology and oxidation resistance for aero-engine applications. Extensive studies have been carried out on wear resistant carbide coatings and abradable coatings used for tribological applications and Pt-AI coatings used for oxidation resistance. The present article presents some perspectives from DMRL on these aspects.

16 illus, 3 tables, 35 ref

019784   Venkat;Das N;Singh S;Sriramamurthy A M (NO, Defence Metallurgical Research Laboratory, Hyderabad-500 058, Email: vyakatpure@yahoo.co.in) : Development of investment shell moulds for precision casting of gas turbine aerofoils. Metals Mater Process 2007, 19(1-4), 203-23.

Defence Metallurgical Research Laboratory has indigenously developed investment casting in DMRL shell molding technology for precision casting of a variety of critical gas turbine components. Ceramic shell molds are built layer by layer through repeated dipping of wax pattern assemblies in slurry of suitable composition of binder-ceramic powder filler followed by stuccoing ceramic grains on every slurry coat. We started in early nineteen eighties with ethyl silicate binder that was available in the country indigenously. Later it was switched to colloidal silica binder instead of ethyl silicate, since the later was incompatible with in-mold innoculant cobalt aluminate. Zircon filler loaded with colloidal silica binder was optimized at around 4.8 kg/liter corresponding to highest green modulus of rupture of 5.860 MPa after drying. Number of coats and grades of stuccoing sands were optimized as per component size, surface finish, geometry, edge-radius and macro-structural requirement. Shell drying parameters such as time, temperature, humidity variation and circulation of air velocity were optimized to avoid first coat cracking and lifting up and improve casting quality. Ceramic core support during injection in wax pattern and casting through optimum platinum pinning were established to achieve respectable casting yield of thin walled columnar grained aerofoil castings. Wax cluster and shell mold integrity was improved through optimum cluster design and clustering fixtures. Shell firing in air was restricted to 950°C in order to avoid micro-cracks resulting from SiO2 phase transition while cooling below 350°C. Mid-chord bulging of columnar-grained aerofoil castings was circumvented through optimum introduction of ultra-fine Al₂O₃ into ceramic slurry to convert binder SiO₂ into mullite and improve mold refractoriness thereby. These molds have proved themselves up to about 1500°C of directional solidification (DS) processing. Shell molds requiring 1550-1600°C DS processing temperature for 3rd generation superalloy single crystal castings have also been developed by employing low sodium content binders with 20% SiO2 content (against 30% SiO2 of earlier binder) and special additives to have adequate mold permeability and collapsibility along with improved refractoriness.

18 illus, 8 tables, 10 ref

019783   Velmurugan R;Gupta N K (NO, Indian Institute of Technology Madras, Chennai-600 036) : Perforation of layered composite plates by impactors of different nose shapes. Def Sci J 2008, 58(2), 227-37.

Conical and hemispherical nose-shaped cylindrical impactors have been used in drop weight impact experiments on 3.1 mm CSM-polyester laminated plates. Based on experimental results, various failure mechanisms and energy absorbed in different failure modes are identified and calculated. It is found that the damage area beyond a certain value of impact energy does not increase. The perforation geometry is the same as that of the impactor irrespective of increased crack length, and complete rotation of petals takes place at impactors radius. It is also observed that the crack length increases with decrease in contact area. But, when the nose is sharp (5 mm hemispherical nose), there is no extended crack beyond perforated region. Blunt nosed (truncated conical impactor with 10 mm nose dia) impactors cause more number of petals/cracks than 10 mm hemispherical nosed impactor and less than 5 mm hemispherical nosed impactor. The petals formed by a cylindrical impactor with 40 mm hemispherical nose are unequal in size, whereas in the case of conical impactors, these are equal. At lower energies, blunt nosed impactors cause more delamination than the hemispherical ones, and at higher energy, it is the reverse. It is found that there exist many visible concentric circular ring hinge mechanisms at the top surface of plates.

6 illus, 4 tables, 17 ref

019782   Uma R N;Manjula G;Meenambal T (Civil Engineering Dep, V.L.B. Janakiammal College of Engineering and Technology, Coimbatore-42) : Determination of reaction rates and activation energy in aerobic composting processes for yard waste. J envir Sci Engng 2007, 49(2), 103-08.

The reaction rates and activation energy in aerobic composting processes for yard waste were determined using specifically designed reactors. Different mixture ratios were fixed before the commencement of the process. The C/N ratio was found to be optimum for a mixture ratio of 1:6 containing one part of coir pith to six parts of other waste which included yard waste, yeast sludge, poultry yard waste and decomposing culture (Pleurotosis). The path of stabilization of the wastes was continuously monitored by observing various parameters such as temperature, pH, Electrical Conductivity, C.O.D, VS at regular time intervals. Kinetic analysis was done to determine the reaction rates and activation energy for the optimum mixture ratio under forced aeration condition. The results of the analysis clearly indicated that the temperature dependence of the reaction rates followed the Arrhenius equation. The temperature coefficients were also determined. The degradation of the organic fraction of the yard waste could be predicted using first order reaction model.

3 illus, 7 tables, 11 ref

019781   Tripathy U K;Kalam A;Dash R (Mathematics Dep, Univ College of Engineering, Burla, Sambalpur-768 018) : Unsteady flow of a non Newtonian fluid past along a rotating porous disk. Ultra Scient phys Sci 2007, 19(3)M, 511-16.

An approximate analysis of the unsteady flow of a non- Newtonian fluid along a rotating porous disk has been carried out. The suction velocity on the wall of the disk is assumed to be time dependent and assuming the rigid body rotation, the equation of motion has been formulated. This equation is solved by the method of Kelley using Fourier series analysis. It is noticed that the velocity components are affected by the terms of order δ² and not by the term of order 5. It is also noted that the flow field is considerably influenced by the non-Newtonian parameter. The effects of other parameters over flow field have been depicted through graphs.

6 illus, 10 ref

019780   Thangadurai G R S;Chandran B S S;Babu V; Sundararajan T (NO, Defence Research & Development Laboratory, Hyderabad-500 058) : Numerical modelling of liquid ramjet combustors. Def Sci J 2008, 58(1), 3-14.

The liquid fuel ramjet system employing a subsonic side-dump combustor is simulated in the study, and the predictions are compared with the available experimental data. The complex combustion phenomenon in a ramjet combustor has been carried out using probability density function (PDF) approach. The complexity arises because of the mixing of fuel and air streams, and the burning of the resultant mixture, within the confined space of the combustion chamber. The predicted numerical results have been validated with the results available in open literature for a two-dimensional case and with in-house experimental data for a three-dimensional case. The methodology allows different designs to be evaluated quantitatively based on the performance metrics such as combustion efficiency, flame stability, etc.

11 illus, 12 ref

019779   Suter M;Benipal G S (NO, Indian Institute of Technology Delhi, New Delhi-110 016) : Aging maxwell constitutive model for concrete. Def Sci J 2008, 58(2), 220-6.

Fully-hydrated concrete not involved in any reaction has been observed to exhibit aging creep. Both the solidification theory and the dissolution-precipitation theory are incapable of predicting such a behaviour. The microprestress theory proposed for this purpose is based upon an ambiguous physical mechanism. In this paper, a constitutive model motivated by Drozdov's adaptive link mechanism has been proposed. The model is capable of predicting aging creep, recovery and relaxation for linear elastic concrete subjected to diverse load histories and temperatures. The theoretical significance of the proposed aging Maxwell model has been critically evaluated.

16 ref

019778   Subramanyam D;Ravindranath K;Varma S V K (Mechanical Engineering Dep, S.V.U. College of Engineering, Tirupati, Email: prasannadsm@yahoo.co.in) : Steady free convective flow of viscous conducting fluid through a circular pipe with constant heat source and NDT variation. Ultra Scient phys Sci 2007, 19(3)M, 639-46.

In the work, Authors have studied the steady laminar magneto hydro dynamic free convective flow of a viscous in compressible fluid in a circular pipe by the consideration of NDT variation. A uniform magnetic field is applied in the azimuthal direction. The solutions for velocity, temperature and Nusselt member have been obtained by using perturbation technique and results are discussed graphically.

9 illus, 18 ref

019777   Srinivas M;Balan K P;Kolla H H;Sharma R; Pavani P V R;Jagtap N B;Narender Y;Sai Madhav M (Structural and Failure Analysis Group, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500 058, Email: sameeramukthi@hotmail.com) : Failure analysis of turbine blade. Metals Mater Process 2007, 19(1-4), 137-42.

Failure of a turbine blade was investigated in detail and presented in this paper. Visual examination revealed that the failure of the blade occurred in the aerofoil region 10 mm above the root platform with multiple cracks starting at leading edge and propagating towards trailing edge upto the centre of the air foil in the concave and convex sides. Stereomicroscopic examination showed chevron markings pointing towards the trailing edge suggesting that fracture might have initiated at the trailing edge. The light yellow colour in the centre of the fracture surface suggests that this portion of the crack surface has seen elevated temperature for long time. The fracture at the leading edge is slanted and brighter indicating that this portion has failed in the end. SEM examination has revealed fatigue fracture initiation regions close to the trailing edge on the concave side. On the convex side of the trailing edge fractographs show crack emanating from the interface between coating at the substrate. Fatigue striations were clearly observed on the fracture surface indicating that crack has propagated by fatigue to certain extent. On the leading edge side, the fracture occurred by overload as indicated by slanting of the fracture surface and shear dimples on the fracture surface. Microstructural examination in the unetched condition showed many cracks along the grain boundaries at the trailing edge, especially, on the concave side. The cracks were also seen through the coating given on the aerofoil. Metallographic examination of a longitudinal specimen cut through the fracture origin area revealed several oxide filled cracks below the fracture surface, which is characteristic of thermal fatigue cracks. it is also to be noted that these thermal fatigue cracks are intergranular and originated at the surface by fracture of surface oxide formed on the protective coating. Further, intergranular cracks were also observed below the protective coating. In the light of these observations, it may be concluded that the turbine blade failure occurred by a combination of thermal fatigue and stress rupture.

1 table, 12 ref

019776   Sridhara Rao D V;Saravanan G S;Muraleedharan K;Balamuralikrishnan R;Muralidharan R;Vyas H P (NO, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058, Email: dvsridhararao@yahoo.co.in) : Transmission electron microscopy characterization of electronic materials and device structures. Metals Mater Process 2007, 19(1-4), 171-79.

Transmission electron microscopy (TEM) is a powerful tool for characterization of electronic materials and device structures. We have established specimen preparation techniques for these materials and device structures. State-of-the-art TEM characterization techniques such as convergent beam electron diffraction (CBED), high resolution TEM (HRTEM) and energy filtered TEM (EFTEM) are being used in understanding materials and microstructural issues. We report in this paper some of our recent results in the area of characterization of low temperature grown GaAs, quantum well and quantum dot structures, and metal-semiconductor interface in metal semiconductor field effect transistor (MESFET) and high electron mobility transistor (HEMT) structures.

10 illus, 13 ref

019775   Singh M;sood D;Gupta R K;Kumar R;Gautam P C; Sewak B;Sharma A C;Mathew T (NO, Terminal Ballistics Research Laboratory, Sector-30, Chandigarh) : Dynamic yield strength of mild steel under impact loading. Def Sci J 2008, 58(2), 275-84.

Dynamic yield strength of mild steel is estimated when impacted by the steel balls launched by two stage-light gas gun in the velocity region 1900-5200 m/s. The ball impact provides a radial momentum to the target material resulting in a crater which spreads out until it is stopped by the target yield strength. The dynamic yield strength of target metal is calculated by incorporating the densities of ball and target material along with experimentally measured crater radius and impact velocity in modified Bernoulli's equation. The dynamic yield strength of mild steel has been found to be around 2000 MPa under high velocity impact, causing the material to deform at strain rates <62> 10⁶ s^-1. Impact phenomenon was also simulated on Autodyn 2-D using Euler processor. Simulation results reveal that the target material is subjected to the highest strain rate of 10⁵- 10⁶ s^-1 at the impact point and then decreases as the penetration progresses through the target. Predicted results of crater radius depth, and splash of material match with the experimental measurements.

10 illus, 3 tables, 14 ref

019774   Singh A K;Ram Mohan Rao C;Srinivasan K (NO, Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabed-500 058, Email: singh_ashok3@rediffmail.com) : Effect of mode of deformation on yield surface of commercial purity titanium. Metals Mater Process 2007, 19(1-4), 89-100.

Effect of mode of deformation on yield surface of commercial purity titanium has been investigated in detail using two different modes of deformation. The material has been unidirectionally railed up to 80% reduction. In order to understand the effect of modes of deformation by rolling, other specimens have also been subjected to 80% reduction by multi-step cross rolling. The yield surfaces have been constructed by Knoop hardness method. The results are compared with other titanium alloys. Finally, an attempt has been made to correlate the changes in yield surfaces due to mode of deformation by rolling and extent of rolling reduction with the development of texture.

12 illus, 19 ref

019773   Sengar S H;Kurchania A K (Renewable Energy Sources Dep, CTAE, Udaipur-313 001, Email: kurchania@redifmail.com) : Design development and testing of composite solar dryer cum cooker. J Fd Sci Technol 2007, 44(4), 357-7.

Solar dryer cum cooker (SDC) developed for drying and cooking food materials consisted of drying chamber, drying rays and two reflectors. Thermal performance test under stagnation condition and heat up condition were calculated for solar cooker. The efficiency for drying maize in solar dryer was 15.55%, in winter. The total cost of SDC was Rs. 2715.

3 illus, 1 table, 4 ref

019772   Satyanarayana D V V;Varma V K;Nagalakshmi G; Srinivasa Rao K;Sridhar T;Vikas Kumar (NO, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500 058, Email: dvvsn@rediffmail.com) : Creep and fatigue behaviour of a near α IMI-834 titanium alloy. Metals Mater Process 2007, 19(1-4), 101-10.

DMRL is actively involved in the development of advanced titanium and nickel based superalloys for aeroengine applications. Some typical results on Low Cycle Fatigue (LCF), Fatigue Crack Growth (FCG), creep and Creep Crack Growth (CCG) behaviour of the IMI-834 titanium alloy, currently being explored for compressor components of aeroengines, have been presented. The alloy exhibits cyclic softening at ambient temperature, especially at high strain amplitudes. The degree of cyclic softening was found to be increasing with increasing magnitude of the applied strain amplitude. Fatigue crack growth resistance of the alloy has been observed to decrease with a decrease in frequency and increase with temperature due to enhanced creep-fatigue interaction. The analysis of results indicate that FCG rates follow inverse square root relation with frequency and logarithmic variation with temperature. The path independent energy integral parameter, C*, correlates well with CCG data for both bimodal and/β microstructures under all test conditions. The alloy with fully transformed β microstructure exhibits better creep crack growth resistance as compared to bimodal ( α+ β) microstructure. Creep crack growth micro-mechanisms for both the microstructural conditions were identified.

12 illus, 17 ref

019771   Satheesh Kumar S S;Sathiyanarayanan S;Raghu T (NO, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad-500 058, Email: traghu5006@yahoo.com) : Processing of Ti-6Ai-4V into thin sheets/foils by pack rolling. Metals Mater Process 2007, 19(1-4), 253-59.

Advanced aerospace systems demand for the use of thin sheet/foil of titanium alloys for the fabrication of honeycombed structures, metallic thermal protection systems and so on for improved load carrying capacity combined with reduced weight. Pack rolling method is preferred to conventional rolling method to process thin sheets and foils out of titanium alloys because of their relatively narrow processing window and possible surface contamination during the elevated temperature processing. This method involves encapsulation of the metal in a protective jacket followed by elevated temperature processing by employing rolling mill. An exploratory study was taken up to process commercial Ti-6Ai-4V alloy into thin sheets by pack rolling. Ti-6AI-4V sheets of 5.5 mm thick with equiaxed alpha + transformed beta structure were encapsulated in mild steel pack and hot rolled in a two high reversing hot rolling mill. Pack rolling was carried out through a series of four stages to obtain a final thickness of less than 300 microns at a constant roll speed of 20 meter/minute. The temperature of processing in each stage was varied and extensive deformation was given to the material in each stage. The evolution of microstructure was studied, micro-hardness measurements were made and room temperature mechanical properties were evaluated.

6 illus, 5 tables, 9 ref

019770   Sar S K;Verma C;Pandey P K (Engineering Chemistry Dep, Centre for Environmental Science & Engineering Bhilai Institute of Tec, Chhattisgarh, Email: santoshar@hotmail.com) : Spectrophotometric determination of sodium lauryl sulphate as aprime anionic surfactant and contaminant in central east Chhattisgarh (Durg-Bhilai region). Rasayan J Chem 2008, 1(2), 236-45.

Surfactant-spectrophotometric method for Sodium Lauryl Sulphate (SLS) coupled with acridine orange (ACO) reagent has enhanced sensitivity for determining anionic surfactant (AS) contaminants, including dangerous chemicals incorporated in the ground and surface potable water through various industrial and domestic sources and has been utilized in a potentially reactive urbanized industrial site of Central East Chhattisgarh (Durg-Bhilai). This paper focuses on the potential application of the method, a patented technology, on domestic, potable, agricultural and industrial sewage waste in this potentially urbanized site (Durg-Bhilai) of Central India. The study identifies the major pollutant spots the source and the points of its spread that would be helpful in identifying not only the potential sources of contamination but also the reasons embarking the mobility of the surfactant spread. Further this work also tends to determine the viability of these potential applications as applied to a large area.

5 illus, 5 tables, 10 ref

019769   Sahoo P K;Dutta D (NO, Institute for Systems Studies & Analysed, Delhi-110 054) : Fuzzy decision aid for technology evaluation. Def Sci J 2008, 58(1), 103- 19.

Fuzzy set theory offers a possibility of handling the data and information involving the subjective characteristics of human nature in decision-making process, which is mostly true in the real-world. This paper presents a fuzzy decision theory method to evaluate the potential of project proposals submitted for final approval of corporate decision makers in any research and development organisation.

1 illus, 11 tables, 8 ref

019768   Roy S;James A R;Bysakh S;Subrahmanyam J (NO, Defence Metallurgical Research Laboratory, DRDO, Kanchanbagh, Hyderabed-500 058, Email: r_subir@yahoo.com) : Comparison of electrical properties of PLZT synthesized by two different methods: soft chemical approach and high energy mechanical milling. Metals Mater Process 2007, 19(1-4), 143-51.

Pb_0.93La_0.07Zr_0.60Ti_0.40O₃ powders were synthesized using two different methods: (i) auto-ignition of metal-polymer precursor gel followed by sintering and (ii) high energy (HE) mechanical milling of oxide powder mixture followed by calcination and sintering. The X-ray diffraction results of the as-burnt powder obtained by chemical synthesis showed the presence of rhombohedral lead lanthanum zirconate titanate (PLZT) with trace amounts of unreacted PbO. The average particle size calculated from transmission electron microscopy (TEM) micrograph of the as-burnt powder was 1.75nm. The powders obtained by mechanical milling showed the formation of the PLZT phase at room temperature along with peaks pertaining to un-reacted PbO. TEM studies on the HE milled PLZT powders revealed particles having a size in the range from 20-30 nm. The chemically synthesized PLZT sample with 94% theoretical density and grain sizes 0.4 -1.0μm showed very high dielectric permittivity -5000 at room temperature. The room temperature dielectric permittivity for the mechanically milled and sintered sample was measured to be ~ 1665. Both the samples underwent completely diffused phase transition at Curie point. The remnant polarization (Pr) of the mechano-chemically synthesized PLZT was found to be higher than (<126> 48 μC/cm²) than that for the chemically synthesized sample (<126>34.6μC/cm²). The value of planar coupling coefficient k_p of the former (0.54) was lower than that of the latter (0.67). The values of coercive fields for the two samples were comparable.

7 illus, 1 table, 25 ref 

019767   Risby M S;Wong S V;Hamouda A M S;Khairul A R; Elsadig M (Faculty of Engineering, Putra Univ, Malaysia-434 00 UPM Serdang Selangor) : Ballistic performance of coconut shell powder/twaron fabric against non-armour piercing projectiles. Def Sci J 2008, 58(2), 248-63.

Body armour technologists over the years are seeking to develop protective systems which are both effective and lightweight. However these hard armour materials are very expensive and have certain weight constraints. From this point of view, natural fibres and fillers have attracted the attention of researchers due to their low density with high specific strengths, abundance, availability, renewability and being environmental-friendly. This paper reports the potential use of coconut shell powder-epoxy composite (COEX) panel bonded with Twaron CT716 fabric as a hard armour material and the characteristics of its fracture imprints from a specific threat level when subjected to ballistic tests' (NIJ Standard 0108.01). It was observed that the imprint patterns on the particulate composite (COEX) could be identified according to effectiveness in impact energy dissipation. COEX/Twaron test panel was found to withstand impact equivalent to NIJ Level II1A using 9 mm FMJ ammunition but perforated at NIJ Level III of 7.62 mm FMJ bullet impacts. Test results showed that COEX panel do possess shock absorbance characteristics and can be utilised as an armour component in the hard-body armour system. Dependency on Twaron fabric layers as ballistic reinforcements has been reduced up to 3-time with 170 per cent improvement on energy-absorption capabilities when using COEX composite as the frontal component of the armour.

16 illus, 1 table, 25 ref

019766   Reddy P R S;Madhu V;Ramanjaneyulu K;Bhat T B; Jayaraman K;Gupta N K (NO, Defence Metallurgical Research Laboratory, Hyderabad-500 058) : Influence of polymer restraint on ballistic performance of alumina ceramic tiles. Def Sci J 2008, 58(2), 264-74.

An experimental study has been carried out to evaluate the influence of confinement of alumina ceramic tiles through polymer restraint, on its ballistic performance. Tiles of 99.5 per cent purity alumina were subjected to ballistic impact against 7.62 mm armour piercing projectiles at velocities of about 820 m/s. The tiles of size 75 mm x 75 mm x 7 mm were confined on both faces by effectively bonding varying numbers of layers of polymer fabrics. These were then bonded to a 10 mm thick fibre glass laminate as a backing using epoxy resin. High performance polyethylene and aramid polymer fabrics were used in the current set of experiments for restraining the tiles. Comparative effects of confinement on energy absorption of tiles with varied number of layers of fabrics were evaluated. It was observed that by providing effective confinement to the tile, energy absorption could be doubled with increase in areal density by about 13 per cent. Photographs of the damage and the effects of restraint on improvement in energy absorption of ceramic tiles are presented and discussed.

14 illus, 3 tables, 10 ref

019765   Rao K S;Noferesti H (NO, Indian Institute of Technology Delhi, New Delhi-110 016) : Brittle failure in heterogeneous crystalline rocks. Def Sci J 2008, 58(2), 285-94.

In a novel attempt to go further in details of the brittle failure process, an extensive study covering both experimental and numerical aspects, has been performed at the Indian Institute of Technology Delhi. Dental plaster has been selected as the base model material to simulate the natural conditions. The specimens were tested in biaxial loading condition after proper curing. To numerically simulate the problem, the UDEC software was used and the effect of geometrical heterogeneity has been studied. A failure criterion is proposed based upon this study.

13 illus, 7 tables, 15 ref

019764   Rajasekharan T;Swaroop Raju P M;Pandey R K; Seshu Bai V;Pradyumna R;Baig M A (NO, Defence Metallurgical Research Laboratory, Hyderabed-500 058, Email: dr.rajasekharan@gmail.com) : Complex-shaped alumina products through rapid prototyping. Metals Mater Process 2007, 19(1-4), 41-6.

Reports fabrication of complex-shaped alumina components by a combination of the techniques of Rapid Prototyping (RPT) and gelcasting. Using the RPT technique, a mould was first fabricated. The mould was built directly from CAD data file, layer by layer. Unlike in the RPT experiments using lost-mould techniques reported in the literature, we developed a polymer mould, which can support larger samples, is easy to remove at a later stage and can allow the formation of finer features in the component with relative ease. The successful moulds were fabricated out of ABS polymer. An aqueous alumina slurry was then prepared and its properties were optimized in terms of solid loading and viscosity. The mould was then filled with the slurry. After allowing the slurry to set inside, the mould was removed and the green component was retrieved. The component was then debindered and sintered.

6 illus, 10 ref

019763   Pinnoji P K;Mahajan P (NO, Indian Institute of Technology Delhi, New Delhi-110 016) : Two wheeler helmets with ventilation and metal foam. Def Sci J 2008, 58(2), 304-11.

Three different two wheeler helmets were studied to investigate their dynamic performance. First is helmet with ABS shell, second is helmet with metal foam, and third is helmet with single groove in the liner foam for providing ventilation. Front and side impact analyses were carried out at 10 m/s velocity by using LS-DYNAT. Forces on the helmet and on the head due to impact were studied with function of time. Pressure and stresses in the brain were investigated and found not to change significantly due to the presence of groove in the liner foam, which was provided to improve the ventilation in helmets. The dynamic performance of a helmet with outer shell as metal foam was examined and compared with ABS material.

10 illus, 2 tables, 9 ref

019762   Palit M;Arout Chelvane J;Pandian S; Balamuralikrishnan R;Singh A K;Chandrasekaran V;Markandeyulu G (NO, Defence Metalurgical Research Laboratory, Hyderabed 500 058, Email: pands@sify.com) : Role of composition, microstructure and grain orientation in optimizing the Magnetostriction of Dy_0.7 Tb_0.3Fe_1.95 alloys. Metals Mater Process 2007, 19(1-4), 47-54.

Giant magnetostriction exhibited by Rfe₂ intermetallics makes them attractive materials for transducer and actuator applications. The R&D activity at DMRL, aimed at realizing large magnetostriction (~ 1300 microstrains) in this exotic material through process development and alloying additions, is described in detail in this paper. In the process development effort, the material preparation consists of pre-casting in required shape and size, followed by zoning in order to induce preferred grain orientation. An alloy of mixed rare earth composition (Dyo.7Tbo.3Fe1.95s) was cast in the form of 8 mm diameter cylindrical rods and subsequently zoned under vacuum at zoning speeds of 18, 36 and 72 cm/h. The zoned samples showed larger magnetostriction (1000 - 1300 microstrains) relative to the cast sample (500 microstrains). The magnetostriction was found to increase with increase in zoning speed from 18 to 72 cm/h. The zoned samples generally exhibited a mixed <110> and <112> texture and with the increasing zoning speed, the <112> texture appears to become stronger. A pro-peritectic (Dy,Tb)Fe₃ phase, found co-existing with the main (Dy,Tb)Fe₂ phase in the cast sample, was absent in the zoned samples. The prevalence of a high temperature gradient during zoning appears to be the reason for the suppression of the (Dy,Tb)Fe₃ phase, enabling the formation of (Dy,Tb)Fe₂ phase from the liquid by congruent solidification. The improvement realized in magnetostriction by zoning is attributed to (i) the development of preferred grain orientation of the (Dy,Tb)Fe₂ along <112> or <110> crystallographic direction, and (ii) the absence of the pro-peritectic (Dy.Tb)Fe₃ phase. As an alternative means of enhancing the magnetostriction, studies on alloying additions are also being pursued. Our recent investigation on B addition is briefly outlined here.

6 illus, 20 ref

019761   Mukhopadhyay A K (NO, Defence Metallurgical Research Laboratory, Hyderabad-500 058, Email: ashim_mukhopadhyay@yahoo.com) : High strength aluminium alloys for structural applications. Metals Mater Process 2007, 19(1-4), 1-26.

In this country, All alloys are finding increasing applications in the fields of both space and defence. It is important that the methods of selection for specific applications, the factors responsible for attaining improved properties and the major processing principles are known to both the producers as well as the potenlial users of these allays This article first describes the fundamental basis of high strength Al alloy design and thereafter it describes the specific role the alloy composition and the neat treatment and hence the resultant microstucture plays for properties such as strength, fracture toughness, stress corrosion cracking (SCC) resistance, fatigua crack initiation and propagation resistance, weldability and surface treatment processes in high sirength 7XXX series Al alloys.

26 illus, 11 tables, 35 ref

019760   Mohandas T;Reddy G M;Rajeswara Rao S V S N N D (NO, Defence Metallurgicla Research Laboratory, Kanchanbagh, Hyderabad-500 058, Email: thondapim@rediffmail.com) : Materials joining R & D at DMRL. Metals Mater Process 2007, 19(1-4), 273-95.

The Defence Metallurgical Research Laboratory (DMRL) is engaged in the development of materials keeping the present and future defence needs in view. The materials being developed are metallic alloys, intermetallics and metal-matrix composites. An understanding on the joining aspects of these materials is of paramount importance for their introduction into service as joining is inescapable in a vast majority of applications. For this reason the laboratory is actively pursuing research and development. The major joining processes, the laboratory is engaged in, are fusion welding, solid state welding and brazing. The areas of work include basic and applied research on microstructure-mechanical property correlations, weldability of materials involving cold and hot cracking studies, development of fillers and ballistic evaluation of welds, residual stress evaluation in welds etc. The welding studies are focused on aluminium alloys, titanium alloys, high and ultra-high strength steels, and metal-matrix composites. Development of vacuum- brazing technology for aluminium and stainless heat exchangers are some of the major development activities that the laboratory has successfully achieved.

34 illus, 15 tables, 70 ref

019759   Mohandas T (NO, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabed-500 058, Email: thondapm@rediffmail.com) : Ceramic-metal joining. Metals Mater Process 2007, 19(1-4), 69-87.

Ceramics have the unique properties of high dielectric strength, inertness in various environments and high temperature strength. For this reason they are employed in vacuum tubes, insulting devices, solid oxide fuel cells etc in combination with metals. Joining of this dissimilar combination is a requirement. Extensively used joining method is brazing. Since electrons in ceramics are covalent/ionic bonded to atoms, are not free to interact in an exchange reaction that is needed in brazing. To overcome this problem historically ceramics are metallised and brazed to metals employing brazing fillers used to braze metals. Current research trends are to employ brazing fillers containing active metals that react with ceramics to form bridge compounds enabling brazing of ceramics without the need to metallise the ceramics. Keeping these trends and the requirements of Defence Research and Development Organisation and other organisations in view the Defence Metallurgical Research Laboratory has focussed its attention in the development of active metal brazing alloys and in understanding the interfacial reactions responsible in the brazing of various ceramic-metal combinations. The studies have shown that the interfacial reactions are controlled by the amount of active metal in the brazing alloy as well as the ceramic-metal combination. Certain metal members exhibited preferential - affinity towards Ti, the active element in the brazing alloy calling for higher concentration of Ti in the brazing alloy or supplementing of titanium from the parent metal to enable the desirable active metal-ceramic interaction. The study has indicated that SiC austenitic stainless steel combination can be brazed with conventional fillers. Development of active metal brazing alloys and brazing studies to understand the interfacial reactions in different ceramic-metal combinations is covered in this article.

20 illus, 5 tables, 91 ref

019758   Mishra A;Rakshit S (NO, Centre for Artificial Intelligence & Robotics, Bangalore-560 093) : Fusion of noisy multi-sensor imagery. Def Sci J 2008, 58(1), 136-46.

Interest in fusing multiple sensor data for both military and civil applications has been growing. Some of the important applications integrate image information from multiple sensors to aid in navigation guidance, object detection and recognition, medical diagnosis, data compression, etc. While, human beings may visually inspect various images and integrate information, it is of interest to develop algorithms that can fuse various input imagery to produce a composite image. Fusion of images from various sensor modalities is expected to produce an output that captures all the relevant information in the input. The standard multi-resolution-based edge fusion scheme has been reviewed in this paper. A theoretical framework is given for this edge fusion method by showing how edge fusion can be framed as information maximisation. However, the presence of noise complicates the situation. The framework developed is used to show that for noisy images, all edges no longer correspond to information. In this paper, various techniques have been presented for fusion of noisy multi-sensor images. These techniques are developed for a single resolution as well as using multi-resolution decomposition. Some of the techniques are based on modifying edge maps by filtering images, while others depend on alternate definition of information maps. Both these approaches can also be combined. Experiments show that the proposed algorithms work well for various kinds of noisy multi-sensor images.

6 illus, 2 tables, 11 ref

019757   Meyers A;Xiao H;Bruhns O (NO, Ruhr-Univ, Bochum, Germany, ) : Finite eulerian elastoplasticity without strain. Def Sci J 2008, 58(2), 194-9.

In the last few decades a number of phenomenological models have been developed for describing elastoplastic materials undergoing finite deformations. They are different in structure, e.g., their formulation is related to the reference or to the actual configuration , i.e., it is a Lagrangean or Eulerian formulation or it may contain elastic and/or plastic deformations. This study has shown that the most simple and straightforward obtained constitutive relation is free from any notion of elastic or plastic deformation. Moreover, it is related to the actual configuration, and thus omits to the greatest possible extent, quantities containing unwanted geometric deformation informations.

27 ref

019756   Madhusudhan Reddy G;Gokhale A A (NO, Defence Metallurgical Research Laboratory, Hyderabad-500 058, Email: gmreddy_dmrl@yahoo.co.in) : On weld solidification cracking in aluminium-lithium alloys. Metals Mater Process 2007, 19(1-4), 297-305.

Solidification cracking susceptibility of AI-Li alloys 1420, 1441 (both of Russian origin), AA 2090, AA 2195 and AA 8090 were investigated with the aid of the Varestraint test. Metallographic examination of the test samples revealed that, in all the alloys, cracking proceeded along interdendritic boundaries with no evidence of crack 'healing' by liquid. The results indicated that alloys 1441, AA 2090 and AA 8090 were susceptible, while alloys 1420 and AA 2195 were resistant to solidification cracking. The cracking tendency was found to be related to the solidification temperature range, and the shape and distribution of the low melting eutectic phases.

10 illus, 3 tables, 28 ref

019755   Madhusudhan Reddy G;Biswas S;Mohandas T (NO, Defence Metallurgical Research Laboratory, dyderabad-500 058, Email: gmreddy_dmrl@yahoo.co.in) : Effect of electron beam oscillation on the microstructure, residual stresses and mechanical properties of TI-6AI-4V welds. Metals Mater Process 2007, 19(1-4), 307-20.

A Poor impact toughness is the main problem in the conventional electron beam welds of TI-6A1-4V. Beam oscillation welding technique has been investigated with a view to alleviate this problem. Microstructure and mechanical properties of the welds were evaluated in the as- welded and post weld heat-treated conditions. Beam oscillation in the electron beam welds exhibited improved impact toughness and ductility as compared to conventional welds. Post weld heat treatment in the sub-transus as well as super-transus regions led to improvement in impact toughness of conventional as well as beam oscillated welds. The observed impact toughness trends are well correlated to crack path deflection and deviation in that, increased crack path deviation results in enhanced toughness. In the as-welded condition residual stress was found to be compressive and is attributed to the predominantly martensitic microstructure. Post weld heat treatment that led to the decomposition of martensite to equilibrium α + β exhibited tensile residual stress as a result of accompanying volume expansion during α ' to α + β transformation.

19 illus, 4 tables, 12 ref

019754   Madhukar S S;Krupanidhi S (Bioinformatics Dep, Sathyabhama Univ, Old Mambalam Road Jappier Nagar, Chennai, Tamil Nadu, Email: krupanidhi.srirama@gmail.com) : ER model to illustrate the health informatic of copper. Curr Trends Biotechnol Pharm 2008, 2(3), 426-32.

Copper is an essential nutrient and acts as a cofactor for many enzymes and proteins. There arc sophisticated mechanisms balancing copper import and export to ensure required nutrient levels, while minimizing its toxic effects. Utilising the tools of data modeling and database design, the health informatics pertaining to Menkes and Wilson's diseases are evaluated and portrayed through conceptual modeling by adopting the Entity-Relationship (ER) modeling grammar. The envisaged ER model displayed five entity types, each with optional and mandatory attributes. The participation constraints and cardinality relationships among entity types constitute the core components of ER model as they render the model self-explanatory. These relationships between entity types are shown through templates (diamond-shaped) in ER model and they communicated intricate network and consequences of copper imbalance. The designed model provided information in nutshell about the molecular evidences such as the genes coding for copper-transporter proteins, the chromosomal location of such genes, the clinical symptoms and possible prophylactic measures. The scope for designing such models to conceptualize the concepts in biology is discussed as the data in biology is neither obsolete nor limited.

1 illus, 3 tables, 17 ref

019753   Lee M H;Chen T C (Chung cheng Institute Of Technology, National Defense Univ, Tao Yuan, Taiwan-335 09, R.O.C.) : Blast load input estimation of the medium girder bridge using inverse method. Def Sci J 2008, 58(1), 46-56.

Innovative adaptive weighted input estimation inverse methodology for estimating the unknown time-varying blast loads on the truss structure system is presented. This method is based on the Kalman filter and the recursive least square estimator (RLSE). The filter models the system dynamics in a linear set of state equations. The state equations of the truss structure are constructed using the finite element method. The input blast loads of the truss structure system are inverse estimated from the system responses measured at two distinct nodes. This work presents an efficient weighting factor γ applied in the RLSE, which is capable of providing a reasonable estimation results. The results obtained from the simulations show that the method is effective in estimating input blast loads, so has great stability and precision.

7 illlus, 15 ref

019752   Langdon G S;Nurick G N;Balden V H;Timmis R B (NO, University of Cape Town, Rondebosch-7701, South Africa) : Perforated plates as passive mitigation systems. Def Sci J 2008, 58(2), 238-47.

Results of tests on fully-clamped circular plates subjected to blast loading directed down a tube. Four series of tests were performed. In one set of experiments, the blast wave was allowed to progress unhindered down the tube to impinge upon the plate, and in the other tests, perforated plates were placed in the path of the blast wave to hinder progression down the tube, disrupting the blast and absorbing some of the kinetic energy. Results of the tests indicate that the perforated plates can be used as a form of passive mitigation.

8 illus, 1 table, 22 ref

019751   Kukudzhanov V N (NO, Russian Academy of Sciences, 119 526, Vernadskogo av.101, b.1, Moscow, Russia) : Multiscale coupled model of thermoelastoviscoplasticity and damage and its application for modelling metal forming processes. Def Sci J 2008, 58(2), 209-19.

The micromechanical model of damage and fracture of elastovisoplastic materials is suggested and applied to studying the processes of damage and fracture. The model describes the scale effect in processes of damage and localization of plastic strain in adiabatic shear bands. For the integration of the suggested equations the new splitting method was used. It was shown that it has significant advantages compare to existing iterative methods. The possibilities of the model suggested for the description of the plastic strain localization are illustrated by several examples.

2 illus, 18 ref

019750   Kashyap S K;Raol J R (NO, National Aerospace Laboratories, Bangalore-560 017) : Fuzzy logic applications in filtering and fusion for target tracking. Def Sci J 2008, 58(1), 120-35.

A fuzzy Kalman filter algorithm is developed for target tracking applications and its performance evaluated using several numerical examples. The approach is relatively novel. A comparison with Kalman filter and an adaptive tuning algorithm is carried out. The applicability and usefulness of fuzzy logic in data fusion is also demonstrated. The performance of both the extended Kalman filter and fuzzy extended Kalman filter is evaluated using real data of a manoeuvering target and it is found that fuzzy extended Kalman filter shows better performance as compared to extended Kalman filter.

33 illus, 3 tables, 8 ref

019749   Kaneko K (NO, Tokyo Univ of Science, 1-3 Kagurazaka, Tokyo-162-8601) : Inelastic deformation behaviour of polypropylent in large strain region and after cyclic preloadings. Def Sci J 2008, 58(2), 200-08.

Inelastic deformation behaviour of polypropylene in tensile large strain region and after axial pre-cyclings is investigated experimentally and analysed using the three-element model based on the overstress theory. In this experiment, cylindrical tubular specimen as well as solid bar specimen are used for torsional loading and volume change is measured to get the true stress-true strain curves. It is found that flow stress is almost constant in strain range of more than 0.1, Poisson's ratio varies depending on strains and the viscosity does not change even after cyclic preloadings in tension, torsion, and compression. The quasi-static stress-strain curve g is represented as a function of temperature. Good agreement can be obtained between predicted results based on obtained constitutive equations having the first invariant of stress (static pressure) effect and the experimental results on both the flow stress and relaxation.

16 illus, 17 ref

019748   Kamat S V;Srinivas M (NO, Defence Metallurgical Research Laboratory, Hyderabad-500 058, Email: samir.kamat64@gmail.com) : Fracture toughness behaviour of ductile material under mixed mide I/III loading. Metals Mater Process 2007, 19(1-4), 111-26.

Group in DMRL has extensively studied fracture toughness behaviour of ductile materials under mixed mode I/III loading. An overview of results and the understanding gained is presented. The salient features of the new experimental test technique that we have proposed which eliminates the need for fatigue pre-cracking and allows the determination of notch root radius independent fracture toughness of a ductile material under mixed mode I/Ill using a single specimen with a finite notch root radius are highlighted, Effect of mixed mode I/Ill loading on fracture toughness of several ductile materials are presented and trie results are rationalized in terms of the deformation field ahead of the crack tip and its effect on the operative fracture mechanism. The effects of stain rate, temperature and ageing on fracture toughness of ductile materials under mixed mode I/Ill loading are discussed and compared with their corresponding effects on fracture toughness under mode loading.

18 illus, 65 ref

019747   Jones N (Impact Research Centre, Univ of Liverpool, Liverpool L69 3GH) : Plasticity methods in protection and safety of industrial plant and structutal systems against extreme dynamic loading. Def Sci J 2008, 58(2), 181-93.

This paper provides an overview of the contributions that plastic methods of analysis can make to the protection of the public and the security of industrial plant against extreme dynamic loading events which involve explosive blast pressures or impact loadings from various projectiles. It is possible, by careful design, to absorb the external dynamic energies through large inelastic deformations of the structural members and specially designed energy-absorbing systems. Both the protection methods are examined briefly, together with some discussion on the dynamic properties of materials, including inelastic failure, and the impact perforation of ductile metal structures. Some phenomena are emphasised that are important for numerical finite-element schemes as well as theoretical methods of analysis.

6 illus, 63 ref