011095   Lachiram;Soni J S (Defence Electronics Research Laboratory, DRDO, Hyderabad-500 005, Email: lachiram@gmail.com) : Optimization of process parameters to enhance performance of the microwave horn antennas by improving surface finish - using taguchi's robust design methodology. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 53-60.

Horn antennas are extremely popular in micro and millimeter wave region and are effectively used in the aerospace and electronic warfare applications. These high frequency horn antennas demand close tolerances and surface finish on internal surfaces. The objective of this work is to demonstrate the optimization of the machining parameters of end milling process to achieve the better surface finish using Taguchi's robust design methodology. In this method, four control factors viz. speed, feed, depth of cut and tool diameter were investigated for the given work material. The presented work was to study the cogency and acceptability of Taguchi's methodology in manufacturing of microwave horn antenna. The quality characteristic identified was surface roughness. Experiments carried out using L'₁₆ Orthogonal Array with four different levels of control factors. The test results were analyzed using 'smaller-the-better' criteria for S/N ratio in order to optimize the process. The experimental results were analyzed, conformed and successfully used to achieve good surface finish on internal surface of microwave horn antenna. The enhancement in performance of the antenna was observed by carrying out the electrical tests. The influence of surface roughness on the electrical performance of antenna was verified by electrical testing.

3 illus, 8 tables, 8 ref

011094   Krishnapur P P;Raghuram T;Khilariawal T;Azaj Ahmed Bhat;Padaki V C (NO, Defence Bio-Engineering & Electromedical Laboratory, Bangalore-560 093) : Reliability assessment through fault tree analysis of combat free fall oxygen system. J Aerospace Qual Relaibility 2007, 3(1), 27-36.

Combat Free Fall (CFF) oxygen system is designed to protect high altitude parajumpers from Hypoxia and Decompression Sickness arising due to the extreme climatic conditions and low barometric pressure encountered at high altitudes. It consists of three subsystems, viz Dilution Demand Oxygen Regulator (DDOR), which dilutes Oxygen with ambient air and maintains proper concentration of oxygen in the breathing gas, Personal Bailout Oxygen System (PBOS) and Pre-Breather Console (PBC), which forms the sources of oxygen to DDOR. To analyse various causes which can result in a catastrophic system failure, a Fault Tree Analysis (FTA) was carried out. FTA is a top down deductive method of analysing the causes or the combination of causes which lead to system failure. FTA results in a graphical representation of various failure events which are interconnected by logic gates. This paper describes the qualitative FTA carried out on CFF oxygen system considering "No Oxygen to Parajumper" as the top event.

8 illus, 5 ref

011093   Krishna Raju V;Dash S K;Prakasha Rao P J V K S;Nanjunda Swamy T S (System Reliability Group, ISRO Satellite Centre, Bangalore-560 017, Email: vkraju@isac.gov.in) : Electrical, electronic and electromechanical parts evaluation by real time X-ray imaging technique. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 114-19.

Effective usage of Advanced Real Time X-Ray Imaging System for evaluation of Electrical, Electronic and Electromechanical parts by Non-destructive Technique. A complex aerospace system requires highly reliable Electrical, Electronic and Electromechanical parts for their application and parts will be evaluated for quality and process related defects before using for onboard application. The advanced Real-Time X-ray system provides image in the order of 5 μm spatial resolution with magnified image on real time. The information provided during the evaluation is vital for acceptance of the parts during incoming inspection, Destructive Physical Analysis and also failure investigation during Failure Analysis. The Non-destructive Technique conducted on Electrical, Electronic and Electromechanical parts using Real time X-Ray system helps selection and usage of defect free parts to meet reliability goal of the mission. This paper also presents case studies and corrective action taken after evaluation process.

12 illus, 1 table, 3 ref

011092   Kar M;Datta K K;Goswami S K (Dep of Electronics and Communication Engineering, Heritage Institute of Technology, Kolkata-700 032) : Simple linear design methodology for two loop lateral missile autopilot. J Instn Engrs-Pt EL 2008, 89(Sept), 4-7.

A methodology for linear design of two-loop lateral missile autopilot has been proposed. The design approach enables to obtain admissible control gains satisfying the stability margin specifications, from a simple set of parametric equations involving the missile system. The parametric equations developed help in assessing the significance of each parameter on system performance. The step-by-step design methodology for the proposed algorithm has been given in details and illustrated with numerical examples using four different types of missile data.

5 illus, 5 tables, 8 ref

011091   Iqbal A (Dep of Electrical Engineering, Aligarh Muslim University, Aligarh-202 002, U P) : Analysis of space vector pulse width modulation for a five-phase voltage source inverter. J Instn Engrs-Pt EL 2008, 89(Sept), 8-15.

Multi-phase ac motor drives are now-a-days considered for various applications due to numerous advantages that they offer when compared to their three-phase counterparts. Analyses different space vector pulse width modulation (S VPWM) schemes for a five-phase voltage source inverter (VSI) used for five-ph machine drive. Model of a five-phase VSI is presented in terms of space vectors. The existing technique utilising only large space vectors are elaborated further in terms of analytical expressions of leg voltage method is also presented utilising both large and medium space vectors to obtain sinusoidal output ph voltages. Analytical expressions of leg voltages are developed for both methods. A detailed perform a comparison based on simulation and experimental results of different methods is also reported.

12 illus, 2 tables, 10 ref

011090   Ingle S;Reddy S;Venkatesh K;Prakasha Rao P J V K S;Nanjundaswamy T S (SRG, ISAC, Bangalore, Email: nswamy@isac.gov.in ) : Meeting the quality requirements for hybrid microcircuits for international spacecraft program-ISRO's experience. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 11-20.

Hybrid Microcircuits used for onboard application are realized from the facility line which is Line Certified and Line Qualified as per the ISRO standard. Prior to realizing the hybrid microcircuits for onboard applications, the circuit designs are verified for de rating requirements, the generated hybrid microcircuit layouts are verified against lay out guidelines, the proto type sample evaluated and awarded go ahead for realization of particular type hybrid microcircuit. The samples from first production of all Hybrid microcircuits developed go through Circuit Type Qualification (CTQ). Subsequent production of that hybrid microcircuit is subjected to screening tests as per the requirement of ISRO standard. As a business venture, ISRO has entered into a few contracts for providing satellite to international customers. The international spacecraft project required that the hybrid microcircuits strictly adhere to the requirements of ECSS Q 60-0A. As a part of documentation requirements, the information on the kitted hybrid microcircuits is listed as the Declared Component List (DCL). On each hybrid microcircuits, the batch is separately provided in the Parts Approval Document (PAD) and is approved by the customers after due verification. To ensure quality of hybrid microcircuits to the international customers, the add on parts that go into the hybrid microcircuits is required to meet the requirements spelt out in ECSS specification, hundred percent precap visual inspection for all kitted hybrid microcircuits, destructive physical analysis on life test samples on each batch of hybrid microcircuits. Radiation tolerance demands of the hybrid microcircuits include meeting Enhanced Low Dose Radiation Specification requirements for all critical dice that are proposed to be used on the spacecraft. This paper provides the experiences during the process of meeting hybrid microcircuit quality requirements to the international customers. This paper also compares the existing practices of screening qualification of hybrid microcircuits vis-a-vis the approach demanded by international satellite customers.

1 table, 3 ref

011089   Hema K S;Ravishankar B N;Jagdish Kumar M N; Sankaran S (Aeronautical Development Establishment, DRDO, Bangalore-560 075, Email: bhat.hema@gmail.com) : Air coupled ultrasonic C-scanning of syntactic foams and sandwich composites with incorporated defects. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 120-7.

Air coupled ultrasonic C-scanning was employed on epoxy syntactic foams and their sandwiches having intentionally introduced defects. Glass microballoons filled Syntactic Foam with introduced defects like through crack, surface crack, loose packing of dough, foreign entities etc. was fabricated using epoxy resin system. Syntactic foam Sandwich sample using glass/epoxy skins was also fabricated with additional defect in the form of debonding between the core and the skin. The developed Syntactic Foam and Syntactic foam Sandwich materials were scanned at ultrasonic frequencies 120 kHz and 400 kHz. The higher frequency scan was able to resolve all the defects that are present in Syntactic Foam. In contrast, defects in Syntactic foam Sandwich were clearly identified at lower frequency scan, since the higher frequency scan revealed additional micro level inhomogeneities which are inherently present. This study amply illustrated the possible use of this technique for Non Destructive Testing to assess the quality of such syntactic foams and sandwich structures used for aerospace applications.

4 illus, 2 tables, 15 ref

011088   Durga Rao K;Sanyasi Rao V V S;Gopika V;Ghosh A K (NO, Bhabha Atomic Research Centre, Mumbai) : Dynamic reliability modeling using monte carlo simulation. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 144-50.

Traditional Fault Tree analysis is widely used for reliability and safety assessment of complex engineering systems. The behavior of components of complex systems and their interactions such as sequence and functional dependent failures, spares and dynamic redundancy management, and priority of failure events cannot be adequately captured by traditional Fault Trees. Dynamic Fault Tree extend traditional Fault Tree by defining additional gates called dynamic gates to model these complex interactions. Markov models are used in solving dynamic gates. However, state space becomes too large for calculation with Markov models when the number of gate inputs increases. In addition, Markov model is applicable for only exponential failure and repair distributions. To address these difficulties, Monte Carlo simulation based approach is used in this work to solve dynamic gates. A case study on Reactor regulation system of NPP is carried out to demonstrate the application of simulation based Dynamic Fault Tree approach to large scale problems.

5 illus, 1 table, 17 ref

011087   Dasgupta S;Ravi Sekhar K;Sankaran S (Aeronautical Development Establishment, DRDO, Bangalore-560 075, Email: samudradg@gmail.com) : Quality control issues: the other side of carbon nanotubes. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 1-10.

Bulk commercial production ventures of nanomaterials in general and Carbon Nanotubes in particular are emerging rapidly owing to increasing number of potential application areas including those in structural composites, electrical / thermal conductivity applications, energy storage systems, semiconductor devices etc. This development is posing a whole new set of questions hitherto unasked regarding the quality control (QC) aspects of these Carbon Nanotubes. The present paper attempts to review this critical issue related to the Carbon Nanotubes beyond the glitter and glamour of their fantastic applications and promises. Though grossly underestimated in the scientific literature till now, these issues may delay or even derail the nanotube bandwagon unless addressed in due time. The paper also shares the authors' hands-on preliminary experiences with quality check of incoming Carbon Nanotube raw materials, the challenges encountered and the lessons learnt in the process.

9 illus, 3 tables, 17 ref

011086   Dasgupta S;Nakra K B S (Aeronautical Development Establishment, DRDO, Bangalore-560 075, Email: kbsankra@gmail.com) : AS 9100 & beyond: in search of excellence in aerospace. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 90-101.

Paper charts the journey of aerospace industry in the path of 'Quality' beyond the milestone of ISO 9001. While the aerospace sector has already embraced the ISO 9001 standards to ensure conformance of its processes to the minimum requirements defined in the Quality Management Systems, the additional criticalities involved in the sector have also led to the evolution of a series of industry specific 'Aerospace Standards' (AS 9100). Today, this series of standards are used and supported by the world's leading aerospace companies as well as throughout their supply chains. But the continual quest for improvement in quality as part of the journey towards 'Excellence' is prompting the industry leaders to consider the adoption of popular 'Business Excellence Models'. Various Business Excellence Models have evolved in the last decade based on different quality awards like the Malcom Baldridge National Quality Award in USA, the Deming's Award in Japan, the European Quality Award in Europe, the Ramkrishhna Bajaj National Quality Award, the Golden Peacock National Quality Award, the CII-Exim Bank Award and the Rajiv Gandhi National Quality Award in India. The present paper briefly summarizes and compares some of the existing Business Excellence Models and their adaptability to the aerospace domain. It also discusses the possibility of tailoring one of the National Quality Award criteria to address the industry specific concerns of aerospace including the additional safety and reliability requirements, supply chain management and R&D intensiveness.

4 illus, 1 table, 13 ref

011085   Chandra Bose A S;Viswanadh G K (Civil Engineering Dep, Govt Polytechnic, , Warangal, Email: smilesubhashbose@yahoo.com) : Analysis of metrological drought using GIS. Int J Envir Dev 2008, 5(2), 219-26.

Meteorological drought severities in the study area were assessed in terms of percentage deviation used by the Indian Meteorological Department (IMD) from the long-term historical data from 1996 to 2006. Monthly drought severity trends for the year 2006 were projected in terms of various thematic maps using ArcGIS 9.2 software. In the study, G-5 sub basin i.e. 'Middle Godavari' sub basin of River Godavari has been considered upto Kaddam reservoir to analyze meteorological drought at each rain gauge sub area. Eight rain gauge stations Khanapur, Kaddam, Neredigonda, Boath, Ichchora, Utnoor, Inderavelli and Bazarhatnoor were identified in and around the study area. Daily rainfall data was collected for all ten rain gauge stations in the study area for a period' of 1996 to 2006 from Bureau of Economics and Statistics, Khairathabad, Hyderabad. Thiessen network was developed for each rain gauge station using Arc GIS 9.2 software. Normal rainfall has been recorded in Khanapur, Kaddam, Neredigonda, Boath, Ichchora, Utnoor, lnderavelli and Bazarhatnooras 881.12 mm, 990.89 mm, 822.27 mm, 1031.96 mm, 1041.99 mm, 1089.66 mm, 1210.49 mm, and 946.97 mm respectively. In the sub basin, highest rainfall was recorded at Inderavelli rain gauge station as 1210.49 mm and lowest is 822.27 mm at Neredigonda rain gauge station.

12 illus, 4 tables, 4 ref

011084   Chanda R S;Banerjee R;Bhandari S;Nath S (NO, Institute of Jute Technology, Kolkata-700 019) : Optimal machine scheduling using fuzzy linear programming. J Instn Engrs-Pt CP 2008, 89(Nov), 17-21.

A fuzzy linear programming based solution approach has been proposed for optimal machine scheduling problem. In the proposed approach, errors in the demand of various products during the next production period are considered to be fuzzy in nature. In conventional linear programming approach it is assume that there is no error in the expected demand of various products. To obtain an optimal solution under fuzzy conditions a fuzzy linear programming approach has been proposed. In the proposed method, expected demand of products and profit has been expressed by fuzzy set notations. The proposed fuzzy lineú programming formulation is then transformed to an equivalent conventional linear programming problem and solutions have been obtained by solving this transformed linear programming problem. The propose method has been applied to a profit maximization related machine scheduling sample problem f illustration.

2 illus, 3 tables, 8 ref

011083   Bhogendra Rao P V R R;Kamakshi Prasad V (Defence Research & Development Laboratory, DRDO, Hyderabad, Email: bhogendra@drdl.drdo.in) : View case driven run-time software architecture for graceful degradation for aerospace applications. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 46-52.

The software for aerospace applications is required to meet strict real-time deadlines and is safety- and mission-critical in nature. Graceful degradation is often an implicit requirement for software of these systems. The design of software for such systems is not as trivial as it is for the business applications. Though a lot of research has taken place in Object-Oriented Design of software for Real-Time systems and mapping of design models to implementation models, these methodologies are applicable to systems which are less complex and do not address the requirement of graceful degradation in the design process itself. However, in practice, the size of the software for aerospace applications is growing and the run-time architecture of software for these applications is becoming increasingly complex. In this paper, we present a generic approach for mapping the design models to run-time architectures resulting in a scalable one that offers graceful degradation. This method is applied in development of a communication interface subsystem of C4I complex and shall be presented as a case study.

3 illus, 11 ref

011082   Bhattacharjee P (Defence Research & Development Laboratory, DRDO, Hyderabad, Email: pradeep9_rqa@yahoo.com) : Structural reliability assessment of pressure vessel. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 159-63.

The Reliability of an aerospace structure is very important. The conventional design practices do not take account of variabilities such as material, process and applied load, moreover simple factor of safety cannot be related to reliability of a structure. This paper discusses methodologies that use probabilistic method. Reliability design analysis of a pressure vessel is considered in this paper. The design problem demonstrated illustrates the application of the method.

2 illus, 4 tables, 5 ref

011081   Bhardwaj J (Centre for Air Borne System, DRDO, Bangalore-560 037, Email: jitesh.bhardwaj@gmail.com) : Application of quality function deployment in product design and development. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 70-77.

Quality Function Deployment (QFD) is a customer-driven formal technique for deriving a product specification by listening to the voice of the customer, identifying and incorporating those needs in design and production of goods and services. QFD aims to listen carefully to Voice(s) of customer (VOC) and these VOC drive the product design and development process. Centre for Airborne Systems (CABS) is a Defence R&D laboratory under Ministry of Defence and involved in research and development of airborne force multipliers. There is a frequent requirement of ATR chassis in different projects of CABS and DRDO. ATR chassis plays an important role in mission-critical applications. An attempt has been made to design, develop and standardize the ATR chassis by using QFD technique. VOC was collected for ATR chassis and converted to technical specifications. Subsequently House of quality was prepared to select an optimal solution to achieve those technical specifications. Based on those solution(s), the final design of ATR chassis was prepared.

5 illus, 3 tables, 14 ref

011080   Behera S;Das S P;Doradla S R (Dep of Electrical Engineering, University College of Engineering, Burla, Sambalpur-768 018) : Hardware implementation of modified SVM technique for soft - switching converter. J Instn Engrs-Pt EL 2008, 89(Sept), 22-7.

The conventional space vector modulation (CSVM) technique for PWM technique for an inverter is well documented in the literature. It cannot be applied in its present form for implementing soft-switching will quasi-resonant dc-link inverter. The conventional SVM is modified to allow soft- switching of the inverter power switches. The hardware circuit for this new technique is also presented. Relevant simulation and the experimental results are also presented to demonstrate the performance of the soft-switching inverter with modified SVM technique.

5 illus, 8 ref

011079   Behera P K;Malolan B;Tribikram Sahoo;Babu M R M (NO, Advanced Systems Laboratory, Hyderabad-500 058) : Quality assurance of pressure vessels by acoustic emission examination techniques. J Aerospace Qual Relaibility 2007, 3(1), 59-68.

Paper looks retrospectively at experiences with the Acoustic Emission (AE) monitoring of new pressure vessels during initial proof pressure test. Conventional Non - Destructive Testing methods may not always reveal the information required to assess the integrity of the vessel. In such situations, acoustic emission technique can be used for detecting the potential delects in pressure vessels before they become catastrophic. For applying this technique the pressure vessel usually requires a mechanical stimulus like pressurisation. Such stimulation produces stresses in the structure. During the pressurisation of the vessel, AE from discontinuities and from other areas of stress concentration can be detected and located. This technique has been used to assess the quality of a rocket motor casing made of 15 CDV6 steel and a filament wound R-Glass epoxy canister during proof pressure testing. AE Testing and result analysis was carried out according to standard procedures. During the tests, AE signals were recorded and post analysis was done to understand the response from the material. The amplitudes of the AE signals that were generated during the reloading cycle were below the amplitudes corresponding to crack growth. Moreover, during the hold at highest pressure of the second cycle, no signals were generated. This may be used as an indicator for checking the soundness of the vessels. Any active flaw shall exhibit AE activity even during pressure holds. Quality assurance of the systems was done in accordance with a set of acceptance criteria based on specimen level tests and available literature.

13 illus, 1 table, 8 ref

011078   Ashok Ponram R;Hari Prasad B;Ramu M (Defence Research & Development Laboratory, DRDO, Hyderabad, Email: ashokponram@rediffmail.com) : Evaluation of dynamic error of coordinate measuring machine. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 37-45.

Coordinate Measuring Machines (CMMs) are extensively used in product development due to its flexibility and high accuracy. Dynamic errors degrade the accuracy of CMMs during high speed measurement. Hence, CMMs are operated at low speed to achieve high accuracy. In the past 50 years, there was a drastic reduction in machining time due to the newer processes. In order to be commensurate with manufacturing time, there is a necessity to operate the CMMs at high speed. During the high speed operation of CMMs, vibration and inertial effects cause dynamic errors to a larger extent. As dynamic errors are of random nature, it is impossible to eliminate them. Detailed study on dynamic errors show that compensation of dynamic errors are possible to certain degree. Deals with evaluation of dynamic errors of DRDL Zeiss (WMM850) CMM due to axis accelerations. The dynamic errors are evaluated theoretically using finite element analysis and error data assessment model is obtained by performing non-linear regression. The theoretical results are compared with experimental results obtained from laser interferometer. The study shows a significant increase in dynamic errors during high accelerations.

14 illus, 4 tables, 9 ref

011077   Arun Kumar G;Srivivasan P S S (Engineering Services, ITC Infotech Ltd, , ITC Infotech Park, Bangalore-600 005, Email: garun55@gmail.com) : Design of force and displacement amplifying compliant mechanisms-a multicriteria optimization approach. J Coop Univ Res Ind Enterpr 2009, 2(3), 23-32.

It is desirable to amplify the force or displacement of an actuator or .transducer in many Micro Electro Mechanical System related applications. Devices that amplify force or mechanical advantage (MA) typically achieve this at the expense of geometric advantage (GA). Likewise, devices that amplify geometric advantage do so at the expense of mechanical advantage. The authors in this paper propose a device topology based on a four-link mechanism with compliant segments in place of hinges. Finite element analysis and optimization were used to develop a set of solutions quantifying the force / displacement trade-off for a variety of loading conditions. Depending on these conditions, a device topology based on a four-link mechanism is capable of multiplying force inputs and displacement inputs. The two objectives (mechanical and geometric advantages) of the device are considered jointly in a multicriteria optimization problem. The efficient design of the proposed device improves the objectives. The outcome of the work will be useful for all type of Strain actuators and automotive industry .

6 illus, 1 table, 15 ref

011076   Appavu Raj R;Marndi R;Bhagat A K L (NO, Integrated Test Range Chandipur, Balasore-756 025) : Qualification tests during development of GPS based flight safety decision system for on-board application. J Aerospace Qual Relaibility 2007, 3(1), 19-24.

Main objective of the test range is to provide safe and reliable launch facility and to provide accurate time find space position information data to the designers/users for performance evaluation of Rockets, Missiles and other airborne vehicles. The prime goal of flight safety is to minimize the potential hazard to life and properties associated with test-launching of flight vehicles under development. It has been accomplished by Real time monitoring of flight vehicle's trajectory and health status by Range Safety Officer (RSO). In order to strengthen the Ilight safety decision making process, on board GPS based Decision Support System (DSS) is required, which aims at providing the present position flight vehicle with respect to Impact limit line. This paper presents the philosophy of flight safety decision making process, proposed on board GPS hardware configuration in brief. It emphasizes on the qualification tests and standard of GPS/DGPS for on board applications. Dynamic simulations and qualification tests in operating and non operating environments aspects of GPS for on board application are also discussed here.

1 illus, 3 ref

011075   Anil Kumar P;Varma D N;Narasimha Rao T; Jagadisan K (ENTEST, RCI, DRDO, Hyderabad) : Structural dynamic analysis and design optimization of electronic bay of terminal guidance system for an air borne vehicle. J Aerospace Qual Relaibility 2009, 3-5(2,1-2,1), 173-8.

The evaluation of dynamic characteristics of an electronic bay of terminal phase guidance system is an essential activity to assess and prove the reliability of the system under dynamic environments. Structural dynamic analysis of electronic bay is carried out in order to assess the design adequacy against the functional requirements. The minimum factor of safety available for all the structural members is observed to be 5 and this lowest factor of safety is corresponding to the severe loading condition. The factor of safety available i.e. 5 against the severe loading condition is observed to be much higher than the recommended value of factor of safety (typically 1.5) due to over design of the electronic bay. Based on this observation the pre-analyzed configuration of the electronic bay is weight optimised within the constraints. The weight optimised configuration exhibited slight reduction in factor of safety from 5 to 4.8. Random vibration response analysis revealed the reduction in response level from 18.6 g_rms to 15 g_rms for weight-optimised configuration when compared to pre-analyzed configuration. Based on this study weight optimised configuration which is meeting the design requirement is recommended for fabrication.

9 illus, 5 tables

011074   Alamelu N;Dananjayan P (Dep of Electrical Engineering, Pondicherry Engineering College, Pondicherry-605 014) : Adaptive band based power control for MC-CDMA system using fuzzy genetic algorithm. J Instn Engrs-Pt CP 2008, 89(Nov), 11-16.

In multi-carrier code division multiple access (MC-COMA) system, the data is transmitted through severe orthogonal sub-carriers and the QoS of a mobile station depends on the strength of each sub-carrier. The base station estimates the received signal to interference noise ratio (SINR) values for each sub-carrier and compares it with the reference INR, which is different for each sub-carrier. The power control command for each sub-carrier is sent to the mobile station and the transmitting power of each user adjusted accordingly. A novel application of fuzzy logic control theory combined with genetic algorithm the sub-channel power control in MC-COMA system has been described in this paper. This technique improves the performance with less outage probability and enhances the traffic capacity of the MC-COM system with reliable QoS.

5 illus, 2 tables, 19 ref

011073   Agrawal V K;Bhalwar R (Rohilkhand Medical College, Pilibhit Bypass Road, Bareilly-243 006, Email: vijenderagrawal@yahoo.co.in) : Household water purification: low-cost interventions. Med J Armed Forces India 2009, 65(3), 260.

Numerous studies have shown that improving the microbiological quality of household water by point-of-use treatment reduces diarrhoea and other waterborne diseases. The most promising and accessible of the technologies for household water treatment are filtration with ceramic filters, chlorination with storage in an improvised vessel, solar disinfection in clear bottles by the combined action of UV radiation and heat, thermal disinfection (pasteurization) in opaque vessels with sunlight from solar cookers or reflectors and combination systems employing chemical coagulation-flocculation, sedimentation, filtration and chlorination. However each of these technologies have limitations and effectiveness can be increased by use of two or more treatment systems in succession for improved treatment and the creation of multiple barriers. In particular those treatments that provide no residual disinfectant, such as boiling, solar treatment, UV disinfection with lamps and filtration could be followed by chlorination to provide a multibarrier approach. Water purifiers based on multiple interventions such as filtration/ultra filtration/ activated carbon adsorption / UV rays disinfection are available in the market which can be used to purify the water at point of use. Water purifiers based on single interventions like candle filters, resins filters or ultraviolet lamp can be used in most places being supplied water after purification. Troops on operational move can purify water by fabric/resins filtration and chlorine disinfection or by flocculent-disinfectant.

1 table, 21 ref

010068   Yesilce Y;Catal H H (Civil Engineering Dep, Dokuz Eylul Univ, Engineering Faculty, 35160, Buca, Izmir, Turkey, Email: yusuf.yesilce@deu.edu.tr) : Free vibration of semi-rigid connected reddy-bickford piles embedded in elastic soil. Sadhana 2008, 33(6), 781-801.

The literature on free vibration analysis of Bernoulli-Euler and Tim-oshenko piles embedded in elastic soil is plenty, but that of Reddy-Bickford piles partially embedded in elastic soil with/without axial force effect is fewer. The soil that the pile partially embedded in is idealized by Winkler model and is assumed to be two-layered. The pile part above the soil is called the first region and the parts embedded in the soil are called the second and the third region, respectively. It is assumed that the behaviour of the material is linear-elastic, that axial force along the pile length to be constant and the upper end of the pile that is semi-rigid supported against rotation is modelled by an elastic spring. The governing differential equations of motion of the rectangular pile in free vibration are derived using Hamilton's principle and Winkler hypothesis. The terms are found directly from the solutions of the differential equations that describe the deformations of the cross-section according to the high-order theory. The models have six degrees of freedom at the two ends, one transverse displacement and two rotations, and the end forces are a shear force and two end moments. Natural frequencies of the pile are calculated using transfer matrix and the secant method for non-trivial solution of linear homogeneous system of equations obtained due to values of axial forces acting on the pile, total and embedded lengths of the pile, the linear-elastic rotational restraining stiffness at the upper end of the pile and to the boundary conditions of the pile. Two different boundary conditions are considered in the study. For the first boundary condition, the pile's end at the first region is semi-rigid connected and not restricted for horizontal displacement and the end at the third region is free and for the second boundary condition, the pile's end at the first region is semi-rigid connected and restricted for horizontal displacement and the end at the third region is fixed supported. The calculated natural frequencies of semi-rigid connected Reddy-Bickford pile embedded in elastic soil are given in tables and compared with results of Timoshenko pile model.

3 illus, 5 tables, 28 ref

010067   Wang X;Pan E (Civil Engineering Dep, Akron Univ, OH 44325-3905, USA, Email: xuwang@uakron.edu) : Analytical solutions for some defect problems in 1D hexagonal and 2D octagonal quasicrystals. Pramana J Phys 2008, 70(5), 911-33.

Study some typical defect problems in one-dimensional (1D) hexagonal and two-dimensional (2D) octagonal quasicrystals. The first part of this investigation addresses in detail a uniformly moving screw dislocation in a ID hexagonal piezoelectric quasicrystal with point group 6mm. A general solution is derived in terms of two functions ϕ1, ϕ2, which satisfy wave equations, and another harmonic function 933. Elementary expressions for the phonon and phason displacements, strains, stresses, electric potential, electric fields and electric displacements induced by the moving screw dislocation are then arrived at by employing the obtained general solution. The derived solution is verified by comparison with existing solutions. Also obtained in this part of the investigation is the total energy of the moving screw dislocation. The second part of this investigation is devoted to the study of the interaction of a straight dislocation with a semi-infinite crack in an octagonal quasicrystal. Here the crack penetrates through the solid along the period direction and the dislocation line is parallel to the period direction. We first derive a general solution in terms of four analytic functions for plane strain problem in octagonal quasicrystals by means of differential operator theory and the complex variable method. All the phonon and phason displacements and stresses can be expressed in terms of the four analytic functions. Then we derive the exact solution for a straight dislocation near a semi-infinite crack in an octagonal quasicrystal, and also present the phonon and phason stress intensity factors induced by the straight dislocation and remote loads.

1 illus, 21 ref

010066   Waghmare A C;Padole P M;Askhedkar R D (Mechanical Engng Dep, KDKCE, Nagpur, Maharashtra) : Multi-objective optimization of setting of resistance spot welding machine using Taguchi,s quality loss function. Indian Weld J 2008, 41(2), 48-56.

Resistance Spot Welding (RSW) is widely used in the industry particularly automobile industry as a predominan technique for sheet metal assembly. Although used for several decades, RSW has a major problem of large variatio in weld quality. For setting RSW machine parameters, welding operators in the industry, generally use trial and err method for getting the desired quality (Weld Indentation, Weld Strength or there combinations) of the weld. With the change in work-shift, each time the machine parameters are reset, thereby wasting time & material an adversely affecting the productivity. It appears that optimum setting in the parameters of RSW machine ma improve the quality of the product. Reports the experimental Multi Objective Optimization of setting of RSW machine using Taguchi's Quali Loss Function, to get the desired quality of the weld. Also the results of multi-objective optimization are compar with the results of single objective optimization.

4 illus, 16 tables, 10 ref

010065   Verma A;Dhingra S;Soni M K (Institute of Instrumentation Engineering, Kurukshetra Univ, Kurukshetra-136 119, Email: verma.avnesh@rediffmail.com) : PID controller of FPGA fed IGBT based inverters, for induction motor in industrial application. VOYAGER 2009, 8(1), 26-9.

Deals with the PID (Proportional Integral Derivative) behavior of the IGBT (Insulated Gate Bipolar Transistor) based inverter. IGBT inverter has been fed through FPGA (Field Programmable Gate Array) controller through SVPWM (space-vector pulse width modulation). The simulation has been carried out using MATLAB with different P & I values. An algorithm for the control of a three-phase induction motor by V/Hz (Voltage/ Frequency) control, driven through space-vector pulse width modulation (SVPWM) technique to drive a voltage source inverter (VSI) has been used The study indicates the effect of PID behavior on the performance of inverter used to run the induction motor control. Further the output response has been find out at different modes and stages of inverter.

5 illus, 9 ref

010064   Veluswamy R;Sivaraman P;Easwaran N; Krishnamurthy M;Rao A S L K (Indira Gandhi Centre for Atomic Res, Central Workshop Div, Kalpakkam) : Salvation of S.S. Surge tank for HTHP loop. Indian Weld J 2008, 41(2), 17-22.

As constituents of nuclear industry, we all know the significance of the stringent specification to the practical level on the manufacture of nuclear components. More so for the primary system of High Temperature High Pressure Loop (HTHP) situated at Water & Steam Chemistry Division (WSCD). The pressurizing of the system is done by heating through immersion heaters provided in the surge tank. The surge tank, at its rated condition, has steam on the top, above the water level. The surge tank has got a150 NB size nozzle at the bottom dished end. A 1500 # flange is welded to this nozzle. The heater unit of the surge tank is connected to this flange. The heater unit consists of a 150 NB, 1500 # blind flange (tube sheet) with eight number of SS U-type immersion heater pins welded to it. Welding of stainless steel heater pin is a demanding task. The task becomes even greater when the job involves welding of 16 pins with a triangular pitch of 25 mm, such as those for the high temperature & pressure loop. Actually, the tank was manufactured by a private firm. During final leak testing, it was found that there were leaks through the heater pins to sleeve welding in three of the heater pins. They could not rectify the leak. Subsequently, the rectification of the weld was referred to CWD. A novel technique was developed and due care was taken to weld the heater pins. The tank was successfully salvaged and tested hydrostatically at 170 bars and pneumatically at 7 bars. The method of fabrication of heater assembly, problems anticipated, problems encountered and measures taken to solve them are deaIt with.

13 illus, 2 tables

010063   Tung S H;Shih M H;Sung W P (Civil and Environmental Engineering Dep, National Univ of Kaohsiung, Kaohsiung 811, Taiwan, Email: shtung@nuk.edu.tw) : Development of digital image correlation method to analyse crack variations of masonry wall. Sadhana 2008, 33(6), 767-779.

The detection of crack development in a masonry wall forms an important study for investigating the earthquake resistance capability of the masonry structures. Traditionally, inspecting the structure and documenting the findings were done manually. The procedures are time-consuming, and the results are sometimes inaccurate. Therefore, the digital image correlation (DIG) technique is developed to identify the strain and crack variations. This technique is non-destructive for inspecting the whole displacement and strain field. Tests on two masonry wall samples were performed to verify the performance of the digital image correlation method. The phenomena of micro cracks, strain concentration situation and non-uniform deformation distribution which could not have been observed preciously by manual inspection are successfully identified using DIC. The crack formation tendencies on masonry wall can be observed at an earlier stage by this proposed method. These results show a great application potential of the DIC technique for various situations such as inspecting shrinkage-induced cracks in fresh concrete, masonry and reinforced concrete structures, and safety of bridges.

13 illus, 8 ref

010062   Szewczyk R;Bienkowski A;Salach J (NO, Industrial Research Institute for Automation and Measurements, Al. Jerpzolimskie 202, 02-486 Warszawa, Poland, Email: rszewczyk@onet.pl) : Temperature dependence of the magnetoelastic characteristics of cores for force sensors utilizing Fe₇₀Ni₈Si₁₀B₁₂ amorphous alloy. Pramana J Phys 2008, 71(3), 591-7.

This paper presents the results of investigation on the influence of temperature on magnetoelastic characteristics of the two ring-shaped cores, made of Fe₇₀Ni₈Si₁₀B₁₂ amorphous alloy. The cores were annealed for 1 h at 350 and 400°C, respectively. The compressive force F was applied perpendicular to the direction of the magnetizing field H in the sample. Special cylindrical backing enables application of the uniform compressive stress σ to the wound ring sample. A resistive furnace heated the experimental set-up. Results presented in the paper indicate a significant influence of the temperature on the magnetoelastic characteristics of FeroNigSiioBiz amorphous alloy. Information about the magnetoelastic characteristics of this material may be useful in the magnetoelastic sensor development. Also this will create new possibilities in the development of physical model of magnetoelastic effect.

4 illus, 13 ref

010061   Sundaram M M;Ananthasuresh G K (Mechanical Engineering, Indian Institute of Science, Bangalore-560 012, Email: meenaskhi@mecheng.iisc.ernet.in) : Gustave eiffel and his optimal structures. Resonance 2009, 14(9), 849-65.

The eponymous tower, as noted by its chief architect Alexandre Gustave Eiffel himself, overshadows his other structural marvels. It is not just the beauty of the Tower that ought to impress an onlooker but also its optimality. Eiffel, excelled in using the material in the most optimal way in many of his structures that include more than 42 bridges and many buildings built in various parts of the world. We also draw an analogy between Nature's designs and Eiffel's designs in the way the material is arranged hierarchically with different shapes at different scales. We consider the Maria Pia Bridge and the Eiffel Tower to illustrate this point and highlight their optimal characteristics. We argue that the structural designs of Eiffel & Co. have an aesthetic appeal that emerges from the economic use of material with their roots in rigorous engineering principles.

11 illus, 8 ref

010060   Suboh S M;Rahman I;Arshad M;Mahyuddin M N (Underwater Robotics Research Group (URRG), School of Electrical and Electronic Engineering, Universiti Sains, Malaysia, Email: surina_ee@yahoo.com) : Modeling and control of 2-DOF underwater planar manipulator. Indian J Mar Sci 2009, 38(3), 365-71.

This study investigates the performance of the fuzzy model reference adaptive control method applied on a 2-dof underwater planar manipulator (MIMO system). Takagi-Sugeno fuzzification is chosen for the fuzzy system and the proportional-integral update law is used in the adjustment mechanism to obtain a fast parameters adoption. The present study consists the proposed controller performance in response to the need to control the manipulator with the added terms in the dynamic equation, i.e., hydrodynamic effects brought about by ocean drift. In the presence of the hydrodynamic and hydrostatic effects of sea water, the performance of the controller is analyzed in terms of servo tracking at each of the manipulator joints. The simulation results demonstrate that the actual joint trajectories of the manipulator for both joints asymptotically follow the desired trajectories defined by the reference model even though the plant is subjected to external disturbances and input variations.

10 illus, 9 ref

010059   Soori U;Arshad M R (Underwater Robotics Research Group, School of Electrical and Electronic Engineering, Universiti Sains, Malaysia, Email: umairsoori.1m07@student.usm.my) : Underwater crowd flow detection using Lagrangian dynamics. Indian J Mar Sci 2009, 38(3), 359-64.

Crowd flow in an underwater scene is used to study fish schooling characteristics. The hydromechanics of fish schooling is quite complicated because it varies in the types of fish underwater. Fish schooling detection contributes toward the study of their locomotion, perception and behavior. For this scenario, we opted to use Lagrangian particle dynamics had been applied to examine the trajectories of an individual particle in the flow. The mathematical algorithm of the Lagrangian Coherent Structure (LCS) is the Finite-time Lyapunov Exponent (FTLE) field the divergence of the particles. The FTLE field is a boundary that divides the flow with respect to its distinct flow dynamics. The algorithm can also do real-time video analyses which can easily be implemented in Autonomous Underwater Vehicles (AUVs). The system is efficient enough to perform the detection of fish schooling as a group flow.

4 illus, 13 ref

010058   Sonmez T (Faculty of Forestry, Artvin Univ, Artvin-08000, Turkey, Email: sonmez_turan@yahoo.com) : Generalized height-diameter models for Picea orientalis L.. J envir Biol 2009, 30(5), 767-72.

The purpose of this paper is to compare major models for height estimation of Picea orientalis L trees based on the individual tree diameter and certain other stand variables. The data were collected from 440 trees of pure and even-aged P. orientalis stands that are located nearArtvin in the northeastern part of Turkey. The data from 406 trees were used for model development and the remaining data were reserved for model validation. A total of 17 non-linear models were fitted to 406 trees. Mean square errors and R^{2 values for the 17 models showed that some models reduced similar height estimation. The model [8] gave the best height estimates for P. orientalis with the highest R2 (0.8703) and the lowest mean square error (5.47). Validation of the models using independent data sets showed that model [8] and [16] gave the best height predictions for this particular dataset.}

4 illus, 5 tables, 28 ref

010057   Sonaje N P;Waikar M L (NO, Shivaji Univ, Kolhapur-416 012, Email: nitinsonaje@yahoo.co.in) : Application of mathcad for hydrological analysis using kostiakov's method. Asian J chem envir Res 2009, 2(1-2), 57-63.

Use of mathematical software packages provides a platform that supports iterative design and parametric analysis through a flexible, transparent interface combined with extensive computing power. This enables a user to develop analytical and design equations that are based on fundamental theories, rather than relying on the black box approach of most commercial design packages. Mathcad offers the hydrologist, computer software that can be customized to meet almost any mathematical need. In a Mathcad, files can be written for any type of design problem and resulting end product represents the typewritten equivalent of hand calculations. The array of mathematical features and capabilities is unrivaled by spreadsheet and formulae are on display, for all to see and check. A solution for analysis of Kostiakov's equation with possible combinations of parameters is presented. The ease of incorporating Mathcad for the intended application is evident and this paper put forth the fact that same is just like undertaking manual analysis using bookish formulae enhanced by technical capabilities of computation owing to customization and transparency attributes of Mathcad. This facilitates easier automation of analysis and design checking processes. The case-study of adoption of Mathcad discussed in paper offers an affordable answer to practical problem of computer efficiency in hydrological analysis.

4 illus, 1 table, 10 ref

010056   Sivakumar Babu G L;Singh V P (Civil Engineering Dep, Indian Institute of Science, Bangalore-560 012) : Numerical analysis of performance of soil nail walls in seismic conditions. ISET J Earthquake Technol 2008, 45(1-2), 31-40.

Evidences from the field and full-scale laboratory tests suggest that soil nail walls perform remarkably well under seismic conditions. In this study an attempt has been made to study the performance of a soil nail wall supporting a vertical cut of 8 m height under seismic conditions. The wall is designed in conventional manner by using the allowable stress design procedure. The response of the wall is then simulated numerically by using a finite element analysis. Seismic data from Bhuj and Uttarkashi earthquakes is used for the pseudo-static and dynamic analyses. To assess the performance of the soil nail wall, parameters such as maximum lateral displacements, development of nail forces, important failure modes of soil nail walls, have been studied under both static and seismic conditions. Results of the numerical analyses indicate that the use of soil nail walls is desirable to impart stability to the retaining systems under seismic conditions.

5 illus, 4 tables, 16 ref

010055   Singh S R;Malik A K (Mathematics Dep, D.N. College, Meerut, Uttar Pradesh, Email: shivrajpundir@yahoo.com) : Two warehouses model with inflation induced demand under the credit period. Int J appl mathl Analysis Applic 2009, 4(1), 59-70.

An optimization inventory policy for a deteriorating item with credit period with shortages and inflation induced demand under two-warehouse system have been presented. It is assumed that the deterioration rates of items in the two warehouses may be different. Authour presented special cases of this model. In one of the case we considered that the capacity of OW is infinite so there is no need of rented warehouse. In other case considers that shortage are allowed and completely backlogged.

3 illus, 3 tables, 10 ref

010054   Rohira K L;Raja A;Anabazghan V (Welding Research Institute, , BHEL, Tiruchirappalli-620 014) : Robot integrated time twin welding of automobile wheels. WRI Jl 2008, 29(4), 5.

"TIME TWIN" is a high performance GMAW process, provides increased deposition rate and excellent welding quality. When integrated with Robot, it further improves the productivity and flexibility of operation. The circumferential fillet joints involved in the automobile wheels were earlier welded by SAW process. As there were certain problems, manufacturers have switched over to conventional GMAW. In the present study robot integrated Time Twin welding is compared with the mechanized mode of Time Twin welding earlier carried out at WRI for welding of wheels. It is found that robot integrated welding Time Twin GMAW technique has the great potential to increase the productivity compared to the single wire & mechanized Time twin GMAW in welding of automobile wheels.

15 illus, 1 table, 5 ref

010053   Ravichandran G (NO, , Bharat Heavy Electricals Limited, Tiruchirappalli-620 014) : Analysis of bending distortion in welded panels using finite element method. WRI Jl 2008, 29(3), 10-16.

Distortion is an inevitable after effect of welding and is faced during the fabrication of various components. Control of distortion during the welding of long panels requires a thorough understanding of the various mechanisms involved. During the welding of panels containing tubes and fins, the build up of the panels can be attempted in two different ways viz. welding two tubes to a fin and welding of two fins to a tube. It has been known that the welding of two fins to a tube produces more distortion whereas welding of two tubes to a fin produces less distortion. This paper attempts to explain the mechanisms involved in the welding of long panels by analyzing a typical cross section of the panel. The transient thermal cycle involved during the welding between the tube to fin is analysed first using finite element method and the curvatures obtained during various time intervals are determined using equilibrium conditions. The displacements are determined from the curvature data for various time intervals. The residual stress build up is also analysed using the above condition. The finite element model employed, the welding conditions analysed and the thermal, displacement and residual stress results are presented in this paper.

10 illus, 8 ref

010052   Ravichandran G (Welding Research Institute, BHEL, Tiruchirappalli-620 014) : Comparison of the thermal cycles during laser welding and GTA welding using finite element method. WRI Jl 2008, 29(4), 20-6.

The thermal cycles during welding are caused by the localised heat input and have great influence on many phenomena which are experienced in welding namely the residual stress build up, distortion, microstructure and mechanical properties etc. Other than the geometric and material parameters, the thermal cycles are dependent not only on the heat input but also the heat source dimensions. In the case of laser beam welding process, the heat source is having a very small diameter and consequently the heat flux density is very high. On the other hand a conventional GTA process has a heat source spread over a large area and the heat flux density is very small. This results in a totally different pattern of thermal cycles in the two processes even though the heat input is the same for the two processes. In this study a thin carbon steel plate with a thickness of 2 mm is taken for analysis and a comparison of thermal cycles in the plate for laser beam welding and gas tungsten arc welding process has been made using finite element method. In-plane model which assumes that the thermal gradient in the thickness direction is negligible is employed in the analysis. The transient and steady state thermal results obtained in the two processes are presented.

5 illus, 1 table, 6 ref

010051   Rathinam A;Ravichandran G;Suresh S;Jinu G R; Sathiya P (Welding Research Institute, BHEL, Tiruchirappalli-620 014) : Experimental study of thermal fatigue in ASTM A 213 grade T-91 steel tube. WRI Jl 2008, 29(3), 17-29.

Steels for high temperature service are a vital part of the construction of power stations. For a long time the ASTM A 213 Gr T-22 steel tubes has been in use world wide in high capacity power stations with excellent operating behavior. The increase of operating steam parameters like pressure, temperature etc, are set a greater demand for the development of high strength steels. ASTM A 213 Gr T-91 material was evolved as an alternative to T-22 steel tubes. The present generation of T-91 steel tubes contains controlled additions of vanadium, niobium and nitrogen. These super heater tubes are subjected to alternating heating and cooling in power plants, causes crack and eventually fails. This phenomenon is termed as thermal fatigue. Thermal shock loading of operating pressure equipment is a common occurrence, particularly in thermal power stations. These tubes are subjected to the temperature of 600°C and producing steam at a temperature of 540°C and a pressure of 160 bar. In this paper a laboratory setup for reproducing thermal fatigue phenomenon were developed to determine the number of cycles to failure occur in tubes. Thermal fatigue tests were conducted in both base and SMAW welded tubes separately which were passed non-destructive tests. The tubes are subjected to thermal cycles from 800°C to room temperature. Oxy-acetylene torch was utilized as a heating source, whereas an improvised facility water bath was utilized for quenching purpose. The tests are carried out until open cracks were identified. Surface cracks are identified in the base metal tubes and weeded tubes after 85 and 53 cycles respectively. Dye penetrant test was carried out in the failed tubes. In base tube lot of longitudinal cracks are identified when compared to transverse cracks in the heating zone. The length of the longitudinal crack is about 14mm and small transverse cracks are also obtained. Similarly in weld tube transverse cracks are developed circumferentially in the weld region, where heat is applied. The length of transverse crack is about 43mm and small longitudinal cracks are also obtained. The tubes are then sectioned and subjected to optical microscopy. Cracks and cavities are observed in both the base and weld tubes. This study revealed that localised heating and cooling causes thermal fatigue which initiates cracks in the tubes.

26 illus, 4 tables, 17 ref

010050   Rao B N;Ashok Kumar R (Structural Engineering Div, Civil Engineering Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: bnrao@iitm.ac.in) : Effect of blow-holes on reliability of cast component. Sadhana 2008, 33(6), 733-51.

Presents a study on the effect of blow-holes on the reliability of a cast component. The most probable point (MPP) based univariate response surface approximation is used for evaluating reliability. Crack geometry, blow-hole dimensions, external loads and material properties are treated as independent random variables. The methodology involves novel function decomposition at a most probable point that facilitates the MPP-based univariate response surface approximation of the original multivariate implicit limit state/performance function in the rotated Gaussian space. Once the approximate form of the original implicit limit state/performance function is defined, the failure probability can be obtained by Monte Carlo simulation (MCS), importance sampling technique, and first- and second-order reliability methods (FORM/SORM). FORTRAN code is developed to automate calls to ABAQUS for numerically simulating responses at sample points, to construct univariate response surface approximation, and to subsequently evaluate the failure probability by MCS, importance sampling technique, and FORM/SORM.

7 illus, 1 table, 25 ref

010049   Ramaswamy A (Civil Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: ananth@civil.iisc.ernet.in ) : Alxandre gustave eiffel: an engineer scientist. Resonance 2009, 14(9), 840-48.

Effect is best remembered for engineering the tower that is a Paris landmark and bears his name. However, Eiffel has many other firsts to his credit. He was one of the first to experimentally obtain material properties of wrought iron that permitted him to proportion structural members in bridges and buildings that he built to sustain the service loads experienced by them. Having struggled to get a good estimate of wind forces on the many tall structures that he designed and constructed during his career, Eiffel was among the first to experimentally obtain data on fluid flow around an object and establish accurately the drag on a body dropped in air in his later years. He developed one of the earliest versions of the 'wind tunnel' that today plays a pivotal role in aerodynamic studies. This article traces the evolution of Alexandre Gustave Eiffel as an engineer and scientist.

6 ref

010048   Raju S P G (Aerospace Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: spg@aero.iisc.ernet.in) : Aerobasics - an introduction to aeronautics, 11. airplane stability and control. Resonance 2009, 14(11), 1071-91.

Stability and controllability of an airplane are essential qualities required for safely and effectively performing any flight. In this article we present the concepts of static and dynamic stability and their relation to controllability of an airplane. This leads us to the concept of handling qualities which are expressed in terms of the properties of transient motions of an airplane following a disturbance. It is difficult to design an airplane for satisfactory handling qualities over a wide range of flight conditions (altitude, flight speed, weight and centre of gravity). It is often advantageous to enhance the flying qualities by using an active control technology. Currently, this technology is implemented on many airplanes by using a fly-by-wire control system. Brief description of this type of control system and its advantages are presented.

15 illus, 4 ref

010047   Raju S P G (Aerospace Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: spg@aero.iisc.ernet.in) : Aerobasics-an introduction to aeronautics, Airplane performance. Resonance 2009, 14(9), 916-28.

Performance of an airplane defines its usefulness and is the primary reason for designing and manufacturing aircrafts. In this article we present simple methods for approximately evaluating the performance of an airplane in normal and accelerated flight conditions. Methods are presented for calculating maximum and minimum flight speed, maximum flight altitude, endurance range, etc. Some flight conditions involving acceleration like take-off, landing, pull-ups and turns are also considered.

9 illus, 2 ref

010046   Rajesh V;Vijaya Kumar Verma S;Nagarjan A S (Mathematics Dep, Narayana Engineering College, Andhra Pradesh, Email: v.rajesh_30@yahoo.com) : Unsteady MHD free convection and mass transfer flow of dissipative fluid with heat generation and thermal diffusion past and infinite vertical porous plate. Int J appl mathl Analysis Applic 2009, 4(1), 71-83.

Problem of MHD free convection and mass transfer flow of viscous conducting fluid past an infinite vertical porous isothermal plate in the presence of heat generation, thermal diffusion and viscous dissipation is studied numerically. The Problem is governed by a coupled nonlinear system of partial differential equations. This system is solved numerically by applying explicit finite difference method. The effects of Heat generation parameter H, Soret number S₀ are examined on Velocity, Temperature and Concentration. It is found that, as Soret number S₀ and Heat source parameter H increase, velocity increases and concentration increases up to certain stage and decreases later.

12 illus, 14 ref

010045   Raja A;Baskaran S;Rohira K L;Joseph A W (NO, , Bharat Heavy Electricals Limited, Tiruchirappalli-620 014) : Optimisation of FCAW parameters for overhead position welding of boiler component. WRI Jl 2008, 29(3), 5-9.

Manufacturing of boiler panels involve fillet welding of fins to tubes. Dedicated SPMs with multiple welding heads and tube feeding arrangements are employed for such jobs. Generally the welding is done from the top. After completion of welding from the top, the panel is tilted 180 degrees and then the welding operation is carried out on the other side. Modern systems developed for boiler panel welding have provision for simultaneous welding from both top and bottom side. In such machines multiple torches are available both at the top and bottom side of the panel. The torches at the top will be welding in down-hand position and those at the bottom will be welding in over-head position. When welding operation is carried simultaneously from both top and bottom, though higher welding speed is possible for the torches working at the top being down-hand position, the same speed would not be possible for the torches at the bottom. The bottom torches can operate only at slightly lower speed. Thus the welding speed will be limited by the welding speed possible for the torches located at the bottom of the panel. In this study the FCAW welding parameters have been optimized for overhead position. The study has been carried out using 1.2 mm diameter rutile type flux cored wire and CO₂ shielding gas. The parameter combination that gives maximum possible welding speed in over-head position while maintaining the required fillet size and penetration has been established using Design of Experiments approach.

10 illus, 1 table, 2 ref

010044   Rai R;Singh C S;Shrivastva B K (Mining Engineering Dep, IT-BHU, Varanasi-221 005) : Application of vetiver grass in slope stability. Indian Min Engng J 2007, 46(4), 27-30.

The Application of vegetation for erosion control and slope stabilization has been widely used in many countries. The different types of vegetation have been used for stabilization but the vetiver grass has many unique features which are ideal for it. The present paper deals with some quantitative parameters of vetiver grass given in literatures (Hengchaovanich, 1998) for slope stabilization and erosion control. Parametric studies were performed to assess the sensitivity of the stability of a slope to the variation in the key vegetation and soil parameters.

4 illus, 3 tables, 8 ref

010043   Rahim K I A;Othman A R;Arshad M R (USM Robotics Research Group, School of Electrical and Electrical Engineering, Universiti Sains Mala, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia, Email: khairulizman@yahoo.com) : Conceptioal design of a presure hull for an underwater pole inspection robot. Indian J Mar Sci 2009, 38(3), 352-8.

Conceptual design of a pressure hull design for an underwater pole inspection system is presented in this study. One of the critical elements in designing the pole-climbing robot is an enclosure for the electronic components that can sustain high pressure and with good protection for underwater application. Four main steps are required in designing the system: selection of the shape of the hull, material selection, hull thickness requirement based on depth limit and safety factor, and end closures design compatible with the hull and design requirements. This study suggests that the preferable material for the proposed structural construction of an underwater pressure hull is aluminum alloy 6061-T6. The methodological approaches applied in the design criteria include analytical calculation and a numerical method for results verification based on the circular cylindrical shape. This paper also proposes that these underwater structures should be able to operate up to 200 m depth.

7 illus, 4 tables, 17 ref

010042   Rachna S;Gupta S M;Bhattacharyya S (Laser Materials Development amd Devices Division, Raja Ramanna Centre for Advanced Technology, Indore-452 013, Email: sudipto_iisc@yahoo.com) : Impedance analysis of Bi_3.25La_0.75Ti₃O₁₂ ferroelectric ceramic. Pramana J Phys 2008, 71(3), 599-610.

AC impedance spectroscopy technique has been used to study electrical properties of Bi_3.25La_0.75Ti₃O₁₂ (BLT) ceramic. Complex impedance plots were fitted with three depressed semicircles, which are attributed to crystalline layer, plate boundary and grain boundary and all three were found to comprise of universal capacitance nature [C = C_0w^n-1]. Grain boundary resistance and capacitance evaluated from complex impedance plots have larger values than that of plate boundary and crystalline layer. The activation energies (Eg.) for DC-conductance in grain boundary, plate boundary and crystalline layer are 0.68 eV, 0.89 eV and 0.89 eV, respectively. Relaxation activation energies calculated from impedance plots showed similar values, 0.81 eV and 0.80 eV for crystalline layer and plate boundary, respectively. These activation energy values are found to be consistent with the E_a value of oxygen vacancies in perovskite materials. A mechanism is offered to explain the generation of oxygen vacancies in BLT eramic and its role in temperature dependence of DC-conductance study.

9 illus, 32 ref