003991   Kuhl A;Brodersen S (NO, , ) : New bearing generation for seal-less pumps. Indian Pumps 2005, 37(1), 15-8.

High on the wish list of every plant owner are an increase in plant safety, a combination of lower, maintenance costs and longer maintanance intervals, and the highest possible degree of availability. This is why seal-less canned motor pumps and mag-drive pumps are increasingly taking the place of traditional pumps fitted with mechanical seals. Zero-leakage pumps units are normally designed with product-lubricated plain bearings. Because of its dependable sliding properties and a high degree of corrosion resistance, silicon carbide (SiC) is the preferred bearing materials. Today, there are a number of SiC-based materials whose properties make them all more or less suitable as product-lubricated pump bearing materials. To take full advantage of the strengths of technical ceramics, there is need for special, ceramic-based designs. At KSB, this has resulted in a patented bearing design.

12 illus

003990   Khanna R;Singh K;Saxena R (Department of Electronics and Communication Engineering, Thapar Institute of Engineering and Technology, Patiala-147 004) : Fractional fourier transform based beamforming for next generation wireless communications systems. IETE Tech Rev 2004, 21(5), 357-66.

Today's mobile communication systems are primarily designed to provide cost efficient wide area coverage for a limited number of users with moderate bandwidth. The future telecommunication will provide the same services in a wireless fashion as provided by fixed network these days and thereby requiring high bandwidths. It is expected that future telecommunication users will be neither willing to sacrifice functionality for the added value of mobility nor to pay more for it - mainly because he will hardly be using any other stationary telecommunication devices. Third generation mobile systems proposals such as UMTS and IMT-2000 only partially address these requirements by providing mobile internet services, with up to 2 Mbps in certain areas. Thus future mobile and wireless applications will require significantly higher data rates and significantly reduced costs per transmitted bit as compared to third generation systems. These requirements on data rate, link quality, spectral efficiency, and mobility cannot be met with conventional beamforming. Therefore new beamforming techniques are essential to increase the spectral efficiency of wireless communication systems. Provides the results achieved through use of a new technique Fractional Fourier transform (FRFT) based beamforming which is especially useful in moving and accelerating source problem. The conventional Minimum Mean Squared Error (MMSE) beamforming in the frequency domain or spatial domain becomes a special case of optimal beamforming with FRFT. The advantage of the proposed optimum FRFT domain beamformer is the practical consideration that the synthesis or analysis of the FRFT can be implemented with the same complexity as the conventional Fast Fourier Transform (FFT).

5 illus, 7 tables, 21 ref

003989   Kansal M L;Arora G;Verma S (Water Resources Development Training Centre, Indian Inst of Technol, Roorkee-247 667) : Optimal location of chlorine booster stations in an urban water distribution network. J Indian Wat Wks Ass 2005, 37(1), 25-36.

Conventionally, sufficient amount of chlorine dosage is added into finished water just before it leaves the water treatment plant, so as to maintain a minimum residual disinfectant concentration even at the farthese demand nodes of the distribution network. Problems associated with this practice include : elevated level of disinfectants that can adversely affect human health, negative economic impacts due to chemical overdosing, elevated levels of carcinogenic disinfection by products (DBPs), and taste and odour problems. An alternative to this practice is to place chlorine booster stations at minimal strategic locations in the distribution system to limit the dosage of chemical at the treatment plant but maintain sufficient residuals at the farthest nodes of the network. The study presents a methodology based on linear and mixed integer programming techniques for identifying locations and number of chlorine booster stations to minimise both number of stations and chlorine dosage.

2 illus, 3 tables, 11 ref

003988   Jain V K;Franz J H (Electrical Engineering Department, Indian Institute of Technology, New Delhi-110 016) : Some design issues in infrared wireless networks. IETE Tech Rev 2004, 21(5), 335-43.

Some issues involved in the design of optical wireless networks are highlighted. Merits and demerits of such networks over the RF networks are given. Sources of noise in indoor optical wireless networks, transmission techniques and modulation schemes used in these networks are discussed.

4 illus, 12 ref

003987   Hasan Md;Arora P;Singhal M;Abbasi S A (Department of Electronics Engineering, Aligarh Muslim University, Aligarh-202 002) : VHDL modeling and FPGA based implementation of a memory efficient Huffman decoder. IETE Tech Rev 2004, 21(6), 371-7.

Very High Speed Hardware Description language (VHDL) based modeling of a memory efficient Huffman Decoder using two-bit clustering technique and Field Programmable Gate Array (FPGA) based implementation are presented here. The two-bit clustering technique not only improves memory efficiency but also helps in reducing symbol search time. For an experimental video data with Huffman codes for 32 symbols extended up to 13 bits, the entire memory space is shown to be reduced to a mere 52 words as compared to a normal 2¹³ = 8192 words i.e., an improvement in efficiency from 0.39<37> to 61.5<37>. The hardware design and rigorous logic and timing simulation have been carried out with the help of High level design and gate level tools. The technology independent nature of VHDL modeling helps in the realization of the design into any technology. The design and implementation has all the inherent advantages of FPGA and has applications in areas where data compression is desirable such as HDTV etc.

4 illus, 3 tables, 6 ref

003986   Gupta P;Paul A K;Bhattacharya S;Neogi N; Mukerjee D (R & D Centre for Iron & Steel, SAIL, Ranchi-834 002) : Design of digital controller for tension control of coiler drive in tandem cold rolling mill. Steel India 2004, 27(1), 10-4.

In a coiler, diameter builds up during coiling operation. In order to coil a strip with fixed tension, the motor torque has to increase with the increase in coil diameter. Controlling tension during cold rolling of strip in a tandem cold mill is an important parameter for improvement of quality of cold rolled products. This paper deals with the design aspect of a digital coiler drive to maintain constant tension between last stand and coiler. The scheme has been implemented in the coiler drive of tandem mill-1 of cold rolling mill, Bokaro Steel Plant.

1 illus, 3 tables, 4 ref

003985   Govindan K R (NO, , Kavoori Consultants, New No: 22, Old No: 45, Janakiram Street, West Mambalam, Chennai-600 033) : Harmonics in lighting systems. Energy Fuel Users J 2005, 54(1), 21-5.

2 illus, 2 tables

003984   Ghosh S;Sahay S K;Das G (National Metallurgical Laboratory, , Jamshedpur-831 007) : Effectiveness of ball indentation technique for evaluating mechanical properties of micro alloyed steel. J Metall Mater Sci 2004, 46(2), 95-105.

Ball indentation technique (BIT) has been employed to evaluate a few mechanical properties (YS, UTS, n, K and hardness) of four micro alloyed steels at room temperature. The design of the set-up for BI experimentation in the laboratory ' scale has been established. To perform and control the test, software on BASIC has been developed. This software also helps to store the load-depth data obtained through a linear variable differential transducer (LVDT). Software on FORTRAN has been developed to analyse the BI results. Different experimental parameters such as indenter speed, diameter of the indenter. minimum size of the specimen required and the BI test procedure have been optimised. The present work is performed on different category of micro alloyed steels for making an attempt to evaluate mechanical properties from small amount of (5X5X2 mm^[3] test specimen. One welded micro alloyed steel has also been considered for the present investigation for finding out point to point variation of mechanical properties. The grain sizes of the four micro alloyed steels are also determined for calculating the strain hardening exponent (n) values. The mechanical properties of the alloys are determined through conventional mechanical test and they were compared with BI obtained test results. The BI test results show a good agreement with those from conventional standard test method.

11 illus, 3 tables, 20 ref

003983   Fernstrom G B (NO, , Pacific Gas and Electric Co) : Steps to successful lighting programs. Energy Fuel Users J 2005, 54(1), 7-11.

From information programs to financial incentives, collective efforts and "technology-push" programs, there are many ways utilities can encourage consumers to use more efficient residential lighting.

003982   Elango A (Dept of Mechanical Engg, A C College of Engineering and Technology, Karaikudi-630 004) : Corrosion behaviour of diffusion coatings deposited by slurry chromising, electro plating and aluminium spraying onto mild steel panel. J Metall Mater Sci 2004, 46(2), 123-33.

Diffusion coatings on metallic surfaces to improve the surface properties like corrosion resistance and wear resistance without affecting their core properties. It is found that chromium plating followed by diffusion annealing in the temperature range of 700-800<144>C results in considerable improvement of corrosion resistance of the carbon steel substrate. Aluminium spray followed by diffusion annealing at 400<144>C improves both the surface hardness level and the corrosion resistance of the untreated carbon steel substrate.

16 tables, 6 ref

003981   Desai M G (Department of Chemical Engineering, Government Engineering College, Gandhinagar-382 011) : Treatment of waste pickling liquor from S.S. rolling mill. Indian chem Engr 2005, 47(2), 122-6.

Describes treatment method for pickling liquor used to wash and dean the S.S. patas (plates) during heat treatment. The process at the end gives red pigment grade iron oxide. The process involves neutralisation with ammonium hydroxide, followed by air oxidation in spray reactor, separation in three-phase separator, drying and calcination. The side stream generated contains ammonium sulphate. The pickling liquor from Dwarka Steel (P) Ltd., Kalol (N.G.) was used for the treatment. The use of spray reactor along with three-phase separator in the pilot scale operation considerably reduced the total time of the process and gave uniform and consistent quality of the oxide.

5 illus, 2 ref

003980   De Almeida A T (NO, , ) : Understanding power quality. Energy Fuel Users J 2005, 54(1), 15-20.

The home electronics revolution and the growing number of utility programs promoting compact fluorescent lamps are ushering the issue of power quality into the residential sector.

6 illus

003979   Chennakesava Reddy A;Sundar Rajan S (Department of Mechanical Engineering, JNTU College of Engineering, Kukatpally, Hyderabad-500 072, Email: dr_acreddy@yahoo.com) : Influence of ageing, inclusions and voids on ductile fracture mechanism in commercial Al-alloys. Bull Mater Sci 2005, 28(1), 75-9.

The objective of the paper is to study the effect of ageing, inclusions and voids on the mechanism of fracture and resultant toughness. It has been found that the voids are initiated at only a fraction of the larger inclusions present. The initiation of voids at small particles in the ductile fracture process appears to have little effect on fracture toughness. The strain hardening capacity has a marked effect on void size, and is an indicator of fracture toughness in the commercial Al alloy.

9 illus, 11 ref

003978   Chande A;Dhekane S;Hemachandra N;Rangaraj N (Modelytics India Pvt. Ltd., , Ist Floor, Sudha Complex, No. 24, WOC Road, Basaveswaranagar, Bangalore-560 079, Email: nh@iitb.ac.in) : Perishable inventory management and dynamic pricing using RFID technology. Sadhana 2005, 30(2-3), 445-62.

In price-sensitive markets, price promotions coupled with an appropriate item replenishment strategy can be effective in controlling the total costs of servicing the market. In supply chains that handle perishable products, inventory management is already a complex problem and the management of products in a dynamic-pricing environment is even more challenging. Monitoring and control of time-sensitive products can be facilitated by the application of radio frequency identification (RFID) technology, which enables non-contact, real-time data collection and efficient interfacing with the management control system in the supply chain. The paper describes an integrated framework for inventory management and pricing in a discrete time (periodic review and ordering) framework, and describes an efficient algorithm, including a new approximation, for the related optimization problem, Authors then propose a suitable architecture for the application of RFID technology in this context, to realize the potential benefits.

4 illus, 6 tables, 28 ref

003977   Chakraborty A K;Ramulu M;Raina a K;Choudhury P B;Haldar A;Sahoo P;Bandopadhyay C (NO, Central Mining Research Institute, Regional Centre, 3rd Floor, MECL Complex, seminary Hills, Nagpur-440 006, Email: cmrirc@satyam.net.in) : Rock fragmentation system analysis applying cause-effect relationship. J Mines Metals Fuels 2005, 53(3-4), 47-54.

Rock engineering system (RES) approach highlighting the cause-effect relationships among the subsystems was proposed by Hudson. The concept is applied with little modifications in the paper to obtain the influence and the interactions of various subsystems in rock fragmentation system in the light of the observations made in three large opencast coal mines in India. The inferences should provide an insight to the rock fragmentation system and scopes to improve its efficiency.

10 illus, 6 tables, 3 ref

003976   Byrne J (NO, , ) : Energy-efficient lighting for the home. Energy Fuel Users J 2005, 54(1), 1-6.

The guide can help consumers find their way through the wide array of energy-efficient lighting choices available today.

003975   Biswas P R;Godiwalla K M;Dev S C (National Metallurgical Laboratory, , Jamshedpur-831 007) : Physical modelling of particle distribution for stir cast metal matrix composite using sand-water and sand - aqueous CaCl₂ slurry system. J Metall Mater Sci 2004, 46(2), 67-93.

Suspension characteristics of particle is a very important aspect in many industrial processes such as waste water treatment, composite making by stir cast technique, mineral and chemical engineering processes. In some cases, homogeneous mixing is desirable, in other cases, either floatation or sedimentation is desirable. Although apparently the phenomenon seems to be very simple, but tailoring the particle movement as desired is not easy. The complexity arises because the particle suspension characteristics depends upon a number of factors viz. particle shape, size and size distribution, specific gravity, its concentration; nature of liquid i.e. its specific gravity, viscosity and surface tension; vessel and stirrer geometry and also the design and process variables. Moreover various forces such as gravity, buoyancy, centrifugal, viscous drag and frictional forces due to collision of particles jointly act on a particle under dynamic rotating motion of the fluid. There is a tendency of hindered settling of particles when its amount is relatively higher than a critical value. In the present study, sand-water slurry system was taken and stirred by a propeller type of stirrer in a cylindrical shaped perspex vessel of diameter 0.10m x 0.15m height, the average particle size being 200 microns of mostly sub-angular to rounded shape. Some studies were also done using a bigger vessel of diameter 0.20 m x 0.30 m height with sand-water and sand-aqueous CaCl₂ (density 1330 Kg/m³) systems. Various factors such as particle size and distribution, its amount, speed of rotation and power input to stirrer, its location in the vessel, direction of rotation of stirrer were varied and their influences on air-entrainment, piping, layering (single phase zones of particles), sedimentation and overall particle distribution were investigated which is a different approach in comparison with the earlier investigations. The distribution was assessed qualitatively (visually and photographically through perspex) and quantitatively by measuring the concentration and sieve analysis of the samples drawn from different locations along the height of the slurry column. Finally a suspension model in terms of particle size distribution was made under various conditions studied. The degree of uniformity of particle distribution is found to be strongly dependent upon stirrer speed as well as the distance between the vessel bottom and the stirrer base. Particle distribution was found to be better in sand-aqueous CaCl2 slurry than in sand-water system. This suspension model can be extended to metallic system considering non-dimensional parameters such as Reynolds Number, Archemides Number, Lyaschenko Number, Froude Number. Up-scaling is also possible using various similitude criteria.

8 illus, 6 tables, 37 ref

003974   Bhanja S K;Mandal A B;Johri T S (NO, Central Avian Research Institute, Izatnagar-243 122) : Standardization of injection site, needle length, embryonic age and concentration of amino acids for in ovo injection in broiler breeder eggs. Indian J Poult Sci 2004, 39(2), 105-11.

In the first experiment, the injection site (broad and narrow) and needle length (11 and 24 mm) for in ovo injection was evaluated on 7th and 14th day of embryonic age. Where 160 standard size fertile eggs were distributed in 8 groups, 4 groups of eggs were injected with AA solution (20 naturally occurring amino acids) to see the effect on hatchability and chick weight at hatch and other 4 groups were injected with the Indian ink to assess the deposition of AA in the developing embryo. In the second experiment the embryonic age for in ovo injection (0,7 and 14th d) and concentration of amino acids (0,0.25 and 0.50 <37> of egg amino acids) were studied in a 3x3 factorial design. When injected with 24 mm needle at both end, either on 7th or 14th day of incubation in majority cases the ink was deposited in the yolk sac of the embryo. Where as with 11 mm needle, when injected at broad end, either on 7th or 14th day of incubation the ink was deposited partly in the air cell and chorio-allantoic cavity, whereas, at narrow end ink was deposited in the albumen of the egg with minimum contact to embryo. Hatchability was poor when AA was injected at broad end with 11 mm needle and at narrow end with 24 mm needle (8.0, 6.25 vs 90.0<37> in control, respectively). Irrespective of concentration of AA, the in ovo injection on 0th (29.0<37>) and 7th (37.3<37>) day had lower hatchability as compared to that on 14th day of embryonic age (81.5<37>) and control (78.0<37>). When chick to egg weight ratio, was compared there was significant difference between concentrations of AA (P<60>0.011) and days of injection (P<60>0.043). AA injected on 14th day had 2.1 <37> higher chick weight as compared to un-injected control.

4 illus, 6 tables, 13 ref

003973   Babu G S;Malakondaiah K (Department of Instrumentation & University Science Instrumentation Cen, Sri Krishnadevaraya University, Anantapur-515 003) : Microcomputer based system for measurement of potassium ion. IETE Tech Rev 2004, 21(6), 403-8.

A computer based potassium ion measuring system is designed and constructed. A precision wide bandwidth dielectrically isolated FET input operational amplifier (OPA602) is used as high input impedance unity gain amplifier for measuring potassium ion concentration. An interfacing circuitry, along with the necessary software to the personal computer, so as to use the computer for measurement has been developed. Automatic temperature compensation along with temperature display is incorporated. The system is reasonably successful in measuring the potassium ion concentration with an accuracy of <145>1<37>.

4 illus, 3 tables, 9 ref

003972   Atkinson B A (NO, , ) : Whatever happened to the E-Lamp?. Energy Fuel Users J 2005, 54(1), 12-4.

In an effort to build a better light bulb, three manufacturers are producing or developing electrode-less induction lamps. But, so far, these lamps have not made it into the residential market.

1 illus

003971   Anbazhagan V;Nagalakshmi R;Raja A (WRI, BHEL, Tiruchirappalli) : Comparison of toughness of GMAW and SMAW of ferritic stainless steel welds. WRI Jl 2004, 25(2), 5-15.

In growing industrial application the ferritic stainless steel (FSS) are widely utilised in components. Due to the weld thermal cycling, grain coarsening takes place in heat affected zone (HAZ) and weld zone, as a result the weld metal exhibit loss of ductility and toughness. This problem is usually addressed through the control of grain size and improvement on tensile elongation and impact toughness. This paper describes how this can be improved in shielded- metal arc welding (SMAW) with CR43Cb (E430+Nb addition) electrode and gas metal arc welding (GMAW) with ER430 filler wire. Mechanical testing, metallography, fracture surface study using scanning electron microscope (SEM). and corrosion tests were carried out to study the improvement of grain refinement effects and toughness.

26 illus, 11 tables, 16 ref

003970   Abhyankar S L (NO, , , Email: infor@indianpumps.org) : Maintenance and troubleshooting of pumps - some common and uncommon tips. Indian Pumps 2005, 37(1), 5-8,12.

There are different methods used by maintenance engineers for proper functioning of pump in process industries. If the maintenance staff at a plant are more busy doing troubleshooting and repairs, it is not very commendable. Trouble-free life of a pump is influenced through all stages of selection, installation and operation of pumps. The article offers various simple, hands-on tips for proper maintenance of pumps.

003969    (NO, , ) : Energy efficiency in an apartment building in Canada. Energy Fuel Users J 2005, 54(1), 26-9.

In 1995, a non-profit cooperative began a retrofit project of a 15-story, 112-unit high-rise apartment building located in Toronto, Canada. The retrofit was required to bring the 30-year-old building and its components up to the requirements of the Ontario Ministry of Housing and the Fire Marshal's Act of Ontario, Some of the changes were designed to improve energy efficiency; others were undertaken for independent reasons such as the rehabilitation of the building envelope, which were also expected to affect energy efficiency.

2 tables

002864   Yomo H;Nguyen C H;Kyritsi P;Nguyen T D;Ramjee Prasad (Cent for TeleInFrastructure (CTIF), Aalborg Univ, Niels Jemes Vej 12, DK-9920 Aalborg, Denmark) : PHY and MAC performance evaluation of IEEE 802.11a WLAN over fading channels. IETE J Res 2005, 51(1), 83-94.

The paper presents an overview of physical (PHY) and medium access control (MAC) layers for IEEE 802.11a, which is a standard of-a broadband high-speed wireless local area network (WLAN). IEEE 802.11 a uses 5 GHz frequency band and its PHY is based on orthogonal frequency division multiplexing (OFDM). Evaluated the OFDM-based PHY and MAC performance of IEEE 802.11 a under various practical wideband channel models, which are abstracted from actual propagation measurements. The effects of different transmission modes defined in PHY on the IEEE 802.11 system performance are investigated. Also discussed the impact of link adaptation, which attempts to choose the best-suited transmission mode according to channel conditions, on the overall system performance.

10 illus, 5 tables, 21 ref

002863   Venkatesh T N;Sarasamma V R;Rajalakshmy S; Sahu K C;Govindarajan R (Flosolver Unit, Natn Aerospace Laboratories, PB 1779, Bangalore-560 017, Email: tnv@flosolver.nal.res.in ) : Super-linear speed-up of a parallel multigrid Navier-Stokes solver on flosolver. Curr Sci 2005, 88(4), 589-93.

In parallel computing, scalability is an important issue and getting linear speed-ups is difficult for most codes. Superlinear speed-up has been achieved on an eight-processor Flosolver system for a multigrid Navier-Stokes code. The physical problem solved, the parallelization method, the speed-ups obtained and possible explanations for this result are discussed.

4 illus, 4 tables, 8 ref

002862   Vengadesan S;Nakayama A (Dep of Appl Mechanics, Indian Inst of Technology-Madras, Chennai-600 036, Email: vengades@iitm.ac.in) : Evaluation of LES models for flow over bluff body from engineering application perspective. Sadhana 2005, 30(141), 11-20.

Three SGS stress closure LES models are evaluated for turbulent flow over a square cylinder. Emphasis is placed on solving engineering-application-type problems on affordable computer resources and within reasonable turnaround times. Results are compared with available experimental data and previously published workshop results. Numerical strategies are kept the same for all the cases. Results are also discussed keeping in view limitations of LES methodology of modelling for practical problems and current developments. It is concluded that a one-equation model for subgrid kinetic energy is the best choice.

4 illus, 1 table, 29 ref

002861   Velmurugan R;Karthikeyan K (Dep of Aerospace Engng and Composite Technol Cent, Indian Inst of Technol Madras, Chennai-600 036) : The reinforcement effect of nanoclay on the damping characteristics of hybrid laminated composities. J Aerospace Sci Technol 2005, 57(3), 345-53.

The hybrid nanocomposite (HNC) laminates are processed by reinforcing the chopped strand mat glass fiber and organically modified montmorillonite clay (OMT) in the polyester matrix. The different percentage by weight (1, 2, 3, and 5%) of OMT are mixed by high speed shear mixer into the polyester matrix and then the HNC laminated are fabricated by introducing pre-mixed polyester-clay into the CSM by hand lay-up technique. A tensile test result reveals that nanoclay in polyester matrix significantly improved the tensile modulus and strength of HNC. The results also indicate that increasing the amount of nanoclay beyond 2% by weight reduces the mechanical properties but surpassing the basic glass fiber filled system. The reinforcing effect of clay enhances the flexural modulus and strength. Considerable improvement in impact energy absorption is seen from the impact test. Dynamic mechanical analysis shows that incorporation of nanoclay improves the storage modulus and loss tangent of HNC. Free vibration tests and logarithmic decrement methods are used to predict the dynamic characteristics such as natural frequency, and damping factor for the first four modes of different clay concentrations. Dynamic results show that second phase nanoscale dispersion between the matrix and E-glass fiber significantly enhances the internal damping of hybrid composites.

15 illus, 2 tables, 20 ref

002860   Vasagam R M (Dr MGR Educ and Res Inst, Deemed Univ, Periyar E V R High Road, NH4 Highway, Maduravoyal, Chennai-600 095) : Pathways for Indian aerospace programmes: next 25 years. J Aerospace Sci Technol 2005, 57(3), 299-300.

002859   Uzunoglu M (Yildiz Tech Univ, Electrical-Electronics Fac Electl Engng Dep, 34349, Besiktas, Istanbul, Turkey, Email: uzunoglu@yildiz.edu.tr) : Harmonics and voltage stability analysis in power systems including thyristor-controlled reactor. Sadhana 2005, 30(141), 57-67.

In the study, non-sinusoidal quantities and voltage stability, both known as power quality criteria, are examined together in detail. The widespread use of power electronics elements cause the existence of significant non-sinusoidal quantities in the system. These non-sinusoidal quantities can create serious harmonic distortions in transmission and distribution systems. Harmonic generation of a static VAR compensator with thyristor-controlled reactor and effects of the harmonics on steady-state voltage stability are examined for various operational conditions.

9 illus, 1 table, 16 ref

002858   Trivedi A;Mehra D K (Electron and Computer Engng Dep, Indian Inst of Technol, Roorkee, Email: adityat67@rediffmail.com) : Space-time adaptive MMSE multiuser receiver structures for wideband CDMA systems. IETE J Res 2005, 51(1), 39-48.

In the paper authors propose computationally efficient space-time multiuser adaptive minimum mean square error (MMSE) receivers using affine projection adaptive (APA) filtering algorithm for asynchronous wideband code division multiple access systems (W-CDMA) in multipath channels. It is found that APA algorithm outperforms normalized least mean square (NLMS) algorithm in convergence characteristics with significant reduction in computational complexity as compared to recursive least square (RLS) algorithm. Three adaptive multiuser receiver architectures are considered, all employ chip-matched filter (CMF) at their front end. In the first two architectures perfect estimation of time delay of individual user is assumed and one CMF is employed per user. The difference between two architectures is that, in the first the samples collected from CMFs are cross-coupled and in the second architecture samples collected for individual users are not combined. In the third architecture, there is no need to estimate the time delay, but fractional sampling is used. It is shown that first architecture outperforms the other two architectures by virtue of its diversity advantage. It is also shown that by exploiting the spatial diversity (using multiple antennas at the receiver) significant improvement can be achieved in the output signal to interference and noise ratio (SINR).

2 illus, 1 table, 21 ref

002857   Suresh R;Venkateswara Rao G (Structural Engng Grp, Vikram Sarabhai Space Cent, Trivandrum-695 022) : Simple analytical solution for active vibration control of intelligent composite and sandwich plates. Indian J Engng Mater Sci 2005, 12(3), 196-206.

Simple analytical formulation of laminated composite plates with integrated piezoelectric layer, used as sensor and actuators for the vibration suppression of intelligent composite and sandwich plates is presented. The first order shear deformation theory is employed to account for the transverse shear deformation. The equations are transformed into the state space form and solved by the linear quadratic regulator (LQR) based control algorithm. The effect of the state and control parameters on the system response is studied. The effect of the thickness ratio of the intelligent plate is also investigated.

16 illus, 15 ref

002856   Sundararajan J K;Maheshwari V;Koilpillai D R (Dep of Electl Engng, Indian Inst of Technol, Madras, Chennai-600 036) : Throughput enhancement in WCDMA using the generalized rake receiver. IETE J Res 2005, 51(1), 19-25.

In a multipath fading channel, when there are many interfering CDMA signals, the multipath causes loss of orthogonality between different signal leading to intracell interference. The Generalized RAKE receiver, proposed recently in the literature, is based on the concept that this interference is not white but colored. Therefore, unlike the conventional RAKE receiver, GRAKE tries to match to the channel as well as whiten the interference. The GRAKE gives a typical improvement of 1-3 dB in SNR for a moderate increase in complexity. In this paper, authors quantify the benefits of using the GRAKE in place of the RAKE in a WCDMA downlink under realistic conditions as specified in the 3GPP standards. The comparison is made both in the presence and absence of channel coding. After performing channel coding, the block error rate and hence the system throughput is evaluated for both receivers in a 144 kbps test case. It is demonstrated that the GRAKE provides significant improvement in BER performance, which translates to higher data throughput, as well as increased capacity.

4 illus, 1 table, 8 ref

002855   Srivastava R B;Awasthi M;Upreti M C;Mathur G N (NO, Defence Mater & Stores Res & Dev Establishment, Kanpur-208 013) : Biosusceptibility evaluations of protective sealants used in aircraft fuel tanks. Indian J Engng Mater Sci 2005, 12(3), 241-7.

Microbial attack on coatings used in aircraft fuel tanks has important implications because such coatings or sealants must remain intact for effective corrosion protection. In general, all the polysulphide based sealants under test were found to be very effective against individual cultures, viz. sulphate reducing bacteria (SRB) and Aureobasidium pullulans. However, when the cultures were introduced collectively (viz. mixed and combination), growth or microorganisms resulted in degradation of coatings to a greater extent. Analysis of electrochemical data reveals that sealant RDL-854 can be used as a broad-spectrum sealant as it was found effective not only against single cultures but also when cultures were introduced collectively.

5 illus, 3 tables, 9 ref

002854   Singhvi R;Venkatesan C (Dep of Aerospace Engng, Indian Inst of Technol Kanpur, Kanpur-208 016) : Modeling of piezo stack actuators and their application in active vibration control. J Aerospace Sci Technol 2005, 57(3), 306-22.

This paper presents the vibration control of a highly simplified two degree of freedom model of a helicopter. The vibration control study has been performed using both active and passive vibration control schemes. In the case of active vibration control, the feedback mechanism affects the stiffness of the system; wheres in passive vibration control, the absorber mass affects the inertia of the system. The active control is achieved using a combination of piezo stack sensor and actuator mechanism. A finite element model for the piezo stack mechanism has been developed to obtain a relation between deformation, applied/induced potential and externally applied mechanical load. The results of this study indicate that inclusion of sensor and actuator units increase the natural frequency of the system due to increase in stiffness of the system. It is observed that in the case of active vibration control, the frequency response of acceleration of the system is highly sensitive to small variations in the magnitude of gain around its optimum value and insensitive to changes in excitation frequency; whereas in passive vibration control, the frequency response does not exhibit any significant change in the characteristics with respect to the variation in the absorber mass, while it is highly sensitive to changes in operating frequency.

13 illus, 3 tables, 14 ref

002853   Shivakumara P;Kumar G H;Guru D S;Nagabhushan P (Dep of Stud in Computer Sci, Manasagangotri Univ of Mysore, Mysore-570 006, Email: hudempsk@yahoo.com) : A novel technique for estimation of skew in binary text document images based on linear regression analysis. Sadhana 2005, 30(141), 69-85.

When a document is scanned either mechanically or manually for digitization, it often suffers from some degree of skew or tilt. Skew-angle detection plays an important role in the field of document analysis systems and OCR in achieving the expected accuracy. Considers skew estimation of Roman script. The method uses the boundary growing approach to extract the lowermost and uppermost coordinates of pixels of characters of text lines present in the document, which can be subjected to linear regression analysis (LRA) to determine the skew angle of a skewed document. Further, the proposed technique works fine for scaled text binary documents also. The technique works based on the assumption that the space between the text lines is greater than the space between the words and characters. Finally, in order to evaluate the performance of the proposed methodology compares the experimental results with those of well-known existing methods.

12 illus, 6 tables, 22 ref

002852   Shetty S D;Shetty P;Sudhaker Nayak H v (Dep of Mechanical Engng, Manipal Inst of Technol, Manipal-576 104, Email: prakash.shetty@manipal.edu) : Inhibition of corrosion of mild steel in hydrochloric acid by N-cyclohexyl-N'- phenyl thiourea. Indian J chem Technol 2005, 12(4), 462-5.

Inhibition of corrosion of mild steel in 0.01-0.1 N HCl solutions by N-cyclohexyl-N'-phenyl thiourea (CPTU) has been studied using potentiodynamic polarization technique. Results obtained reveal that CPTU performs excellently as anodic inhibitor for mild steel in HCl solution. The inhibitor functions through adsorption following Temkins' adsorption isotherm. The influence of parameters like temperature, hydrochloric acid concentration and inhibitor concentration on the corrosion of mild steel has also been studied.

1 illus, 2 tables, 15 ref

002851   Sheela G;Muralidharan V S;Pushpavanam M (Cent Electrochem Res Inst, , Karaikudi-630 006, Email: malathypush@yahoo.com) : Corrosion behaviour of electrochemically joined aluminum and stainless steel. Indian J chem Technol 2005, 12(4), 466-71.

Two dissimilar metals viz., aluminum and stainless steel (SS) were joined electrochemically by heavy nickel deposition. Potential-time behavior, Tafel extrapolation method and galvanic coupling experiments were conducted to study the corrosion behavior of the three individual metals in 5% aqueous sodium chloride acidified with acetic acid, alone and in combination. The systems behaved differently in simple immersion test and on coupling with each other. In simple immersion test, nickel and SS were nobler to aluminum. Coupling of aluminum and nickel (bi-metallic) resulted in dissolution of both metals, the rate of nickel being lower. Potentiodynamic polarization experiments showed that the aluminum-SS bi-metallic system has the highest corrosion rate than aluminum-Ni or SS-nickel. Aluminum exhibits pitting type corrosion when coupled to nickel. Experiments with electroplated specimens and SEM analysis confirmed that in aluminum-nickel couple both metals corrode, the corrosion of nickel being considerably lower. Formation of elemental nickel on aluminum surface also confirmed the above result.

8 illus, 4 tables, 9 ref

002850   Sharma P;Kukreja P;Choudhary V;Narula A K (Sch of Basic and Appl Sci, GGS Indraprastha Univ, Kashmere Gate, Delhi-110 006, Email: aknarula1@rediffmail.com) : Curing and thermal behaviour of epoxy resin in the presence of aromatic imide-amines. Indian J Engng Mater Sci 2005, 12(3), 259-64.

Paper describes the synthesis and characterization of aromatic imide-amines obtained by reacting pyromellitic di-anhydride (P)/or benzophenone 3,3', 4,4'-tetracarboxylic dianhydride (B) (1 mol) with excess of 4,4'-diaminodiphenyl ether [E]/or 4,4'-diaminodiphenyl methane [M]/or 4,4'-diaminodiphenyl sulfone [S] and their use as curing agents for diglycidyl ether of bisphenol-A (DGEBA). Structural characterization of imide-amines was done using FTIR, ¹H-NMR, ¹³C-NMR spectroscopy and elemental analysis. These aromatic imide-amines were used as curing agents in order to investigate the effect of structure on the curing and thermal behaviour of diglycidyl ether of bisphenol-A (DGEBA). Curing behaviour of DGEBA in the presence of stoichiometric amounts of aromatic imide-amines was investigated by differential scanning calorimetry (DSC). A broad exothermic transition in the temperature range of 180-230°C was observed in all the samples. The peak exotherm temperature (T_p) was lowest in case of imide-amines based on B and M and highest in case of imide-amines based on P/or B and S. Thermal stability of the isothermally cured resins was investigated using dynamic thermogravimetry in nitrogen atmosphere. The char yield was highest for resin cured with imide-amines based on B and E.

7 illus, 3 tables, 18 ref

002849   Shankar Kumar K R;Chockalingam A (Dep of Electl communication Engng, Indian Inst of Sci, Bangalore-560 012, Email: achockal@ece.iisc.ernet.in) : Performance analysis of parallel interference cancellation in multicarrier DS-CDMA systems. IETE J Res 2005, 51(1), 27-37.

In the paper, Authors has presented and analyzed the performance of a parallel interference cancellation (PIC) scheme for multicarrier (MC) direct-sequence code-division multiple-access (DS-CDMA) systems. At each cancellation stage in the proposed PIC scheme, on each subcarrier, a weighted sum of the soft outputs of the other users in the current stage is cancelled from the soft output of the desired user (rather than making hard bit decisions of the other users and regenerating and canceling the interfering signals) to form the input to the next stage. At the last stage, the interference cancelled outputs from all the subcarriers are maximal ratio combined (MRC) to form the decision statistic. The scheme has the advantage of not requiring the amplitude estimates of the other users. Authors derive analytical expressions for the bit error rate (BER) at different stages in the proposed PIC scheme on Rayleigh fading channels. Analytical results are found to agree well with the simulation results. The results show that the proposed PIC scheme offers better interference suppression capability than the conventional matched filter (MF) receiver. Authors also obtain bounds on the coded BER of the proposed PIC scheme for a convolutionally coded multicarrier DS-CDMA system where the PIC-MRC output feeds a soft decision Viterbi decoder.

9 illus, 29 ref

002848   Shalini;Sharma T;Saxena V K;Upadhyay A L N (Dep of Fuel and Miner Engng, Indian Sch of Mines, Dhanbad-826 004) : Reduction of iron ore pellets with non-coking coal. J Instn Engrs-Pt MM 2005, 86(April), 34-6.

In the study an attempt has been made to study the reduction behaviour of iron ore pellets with non-coking coal under isothermal condition in the temperature range of 900°C to 1050°C. The variables (parameters) studied are reduction temperature, reduction time and quality of coal. Relatively higher degree of reduction was obtained with low ash coal than the high ash coal Eduction of iron ore pellets in packed bed of coal is governed by the diffusion of carbon used or carbon monoxide produced during reduction. Diffusion control model for reduction is applicable in this case and the value of activation energy is 59.386 kJ/mole.

4 illus, 3 tables, 8 ref

002847   Sarkar S K;Bandyopadhyay N R;Sahu P K;Maji B (Dep of Electron and Telecommunication Engng, Jadavpur Univ, Kolkata-700 032) : Parameter optimisation for better low dimensional alloy semi-conducting materials. J Instn Engrs-Pt MM 2005, 86(April), 29-33.

Neural network algorithms are best known for their abilities to adapt to the changing characteristics of the surrounding environment by adjusting system parameter values. In the present work artificial neural network is employed to predict the various system parameters for In_0.53Ga_0.47. As alloy semiconducting material to make it suitable for high frequency applications. A feed forward back propagation network has been used for this purpose.

4 illus, 4 tables, 18 ref

002846   Roy T K (Dep of Metallurgy and Mater Engng, Dr. M N Dastur Sch of Mater Sci and Engng Bengal Engng and Sci Univ, Shibpur-711 103) : The steel -sun: rise so far and beyond. J Instn Engrs-Pt MM 2005, 86(April), 1-15.

18 illus, 15 tables, 26 ref

002845   Roy a (Nuclear Sci Cent, , Aruna Asaf Ali Marg, PO Box 10502, New Delhi-110 067) : First beam acceleration with niobium-based superconducting linear accelerator at NSC. Curr Sci 2005, 88(4), 549-50.

1 ref

002844   Rastogi R (Dep of Inf Technol, , ) : Indian electronics industry - geographical spread. Elect Inf Plann 2004, 31(9-12), 211-49.

7 tables

002843   Perumal R V (Liquid Propulsion Systems Cent (LPSC), Vikram Sarabhai Space Cent, Thiruvananthapuram-695 022) : Launch vehicle technology development and perspectives. J Aerospace Sci Technol 2005, 57(3), 301-5.

6 illus

002842   Patel S K;Dattaguru B;Ramachandra K (Gas Turbine Res Establishment, , CV Raman Nagar, Bangalore-560 093) : Experimental and numerical prediction of surface crack growth in fatigue in finite width plate. J Aerospace Sci Technol 2005, 57(3), 323-31.

In the thick components such as gas turbine disks, the cracks usually manifest in the form of part-through or embedded elliptical cracks. The shape of surface crack varies during the crack propagation and significantly affects the fatigue life predictions, of the surface cracked components. Crack propagation of semi-elliptical cracks in a finite width specimen of a gas turbine material subjected to fatigue load has been studied experimentally and numerically. The numerical simulation was accomplished, by first extending the applicability of available stress intensity factor empirical equation for semi-elliptical cracks to finite width solid. Using this empirical equation for stress intensity factor, the effect of change in the crack shape on the crack propagation life is simulated by numerical models. Also, in order to include the effect of crack closure in the numerical prediction of growth of surface cracks, a ratio of crack closure factor between depth and surface locations of a semi-elliptical crack was obtained by experiments. The experimental observations were used in correlating the numerical predictions for crack shape progression and crack propagation life.

13 illus, 1 table, 23 ref

002841   Pandey R (Dep of Electron and Commun Engng, Natn Inst of Technol, Kurukshetra-136 119, Email: rajoo_pandey@rediffmail.com) : Blind antenna beamforming in DS-CDMA systems using nonlinear networks. IETE J Res 2005, 51(1), 69-74.

The capacity of code division multiple access (CDMA) systems is limited by interference and can therefore be increased by techniques that suppress interference. Adaptive techniques using multiple antennas are generally used for interference suppression in the receiver. Blind adaptive schemes are attractive as they do not require any training sequence. Most of the commonly used blind algorithms optimize some cost functions that are generally non-convex and nonlinear functions, of tap weights, when implemented using linear filters. Therefore the use of nonlinear structure that can form nonconvex decision regions is more suitable for this purpose. In this paper a blind antenna beamformer using constant modulus algorithm (CMA) has been implemented, where the beamforming network has complex nonlinear functions. Simulation results indicate better performance than the linear filters in terms of signal to interference and noise ratio (SINR).

7 illus, 15 ref

002840   Navin D P;Murthy D S R (NO, Structural Engng Res Cent, CSIR Campus, Taramani, Chennai-600 113) : Probabilistic study for fracture strength of through-wall cracked pipes. J Instn Engrs-Pt MM 2005, 86(April), 24-8.

Fracture strength of piping components used in primary heat transport system of nuclear power plants is of great importance to ensure safety against improbable accidental loads. The net-section plastic collapse moment is used to calculate the maximum moment capacity of pipes having flaws/cracks. A probabilistic study has been carried out on the results of 73 experiments conducted on through-wall circumferential cracked pipes to obtain a reliable estimate of maximum moment capacity. Frequency distribution of experimental maximum moment of pipes normalised by their net-section plastic collapse moments was studied and a best-fit was found using goodness-of-fit test. Based on the study, a reduction factor has been suggested for the net-section plastic collapse moment to predict the maximum moment capacity for 95% percentage of confidence.

3 illus, 3 tables, 13 ref

002839   Nataraj M;Arunachalam V P;Dhandapani N (Dep of Mechanical Engng, Government Coll of Technol, Coimbatore-641 013, Email: m_natanuragct@yahoo.com) : Optimizing diesel engine parameters for low emissions using Taguchi method: variation risk analysis approach. Indian J Engng Mater Sci 2005, 12(3), 169-81.

Experimental study has been carried out to simultaneously optimize several diesel engine designs and operating parameters for low exhaust emissions using Taguchi method. A single cylinder (DPF make) diesel engine equipped with a high pressure, cam driven mechanical injector has been used in this experiment. The effects of changes in engine design/operating parameters-nozzle spray holes, piston-to-head clearance, nozzle protrusion, injection control pressure, start of injection timing and swirl level on diesel engine emissions have been investigated at two engine operating conditions, i.e., 40% of maximum load and 80% of maximum load using Taguchi design of experiment methods. Emissions are quantified and optimum parameter setting has been arrived. Measurement of exhaust emissions for the optimized engine showed that CO, HC and smoke emissions are significantly lower than those obtained for the baseline engine. Taguchi method has been found to be a useful technique for the simultaneous optimization of several engine parameters and also for predicting the effect of various design parameters on diesel exhaust emissions.

5 illus, 12 tables, 11 ref

002838   Latheswary S;Valsarajan K V;Sadasiva Rao Y V K (Dep of Civil Engng, Coll of Engng, Trivandrum-695 016) : Analysis of smart composite plates - a finite element approach. J Aerospace Sci Technol 2005, 57(3), 354-64.

A 4 noded finite element with seven degrees of freedom per node, based on higher-order shear deformation theory, is used for the analysis of smart composite plates. This model does not include voltage electric potential as a degree of freedom and is valid for both surface-mounted and embedded piezoelectric elements either distributed or placed in patches. The effect of actuator voltage on the static and dynamic behaviour of such plates is studied. It is seen that the reduction in deflection is proportional to the actuator voltage and the actuator voltage does not have significant influence on the frequency of vibration. An active control of vibration is achieved by suitably amplifying the voltage sensed by the sensor.

15 illus, 25 ref