005744   Mandal R;Mitra P;Chowdhury S;Chowdhury S P; Chowdhury S;Pal S K (Dep of Electl Engng, Jadavpur Univ, Kolkata-700 032) : Application of eigenvalue analysis for improvement of small signal stability of a multi machine system. J Instn Engrs-Pt EL 2006, 87(June), 13-18.

Eigenvalue-based method has been applied for the analysis and improvement of small-signal stability of both unregulated and regulated multi-machine system. A 9-bus system has been considered as the test system. Initially, the mathematical models for AVR and PSS of the generator are developed. Afterwards, the differential equations are linearised around the operating point. Thereafter, the state space model of the system with generator and PSS is formed and the eigenvalues are calculated from that slate matrix. The participation factors are calculated for the unregulated system from the eigenvalues and eigenvectors and the highest participation of the machine in the particular mode of instability is determined from the absolute values of the participation factors. Now, the PSS is added to that particular machine for enhancement of small-signal stability of the system. The same eigenvalue-based approach is then applied for the regulated system and the stability of the system is determined from eigenvalue analysis. Finally, it is shown that application of PSS has greatly contributed for the improvement of small-signal stability of the system by converting the positive real part of the eigenvalue of that particular mode to negative.

3 illus, 8 tables, 10 ref

005743   Mallikarjuna J M;Ganesan V (Dep of Mechanical Engng Internal Combust Engines Lab, Indian Inst of Technol Madras, Chennai-600 036) : Optimization of inlet valve closure timing and clearance volume of a SI engine for better performance at part loads-a numerical and experimental approach. Indian J Engng Mater Sci 2006, 13(4), 307-21.

Computer simulation and experimental investigations on a single cylinder, four-stroke, spark ignited engine are carried out to optimize inlet valve closure timing and clearance volume for better part-load performance. The simulation procedure involves thermodynamic and global modeling techniques. Many sub-models have been used for predicting heat transfer, friction and gas exchange processes. Unburned hydrocarbons, carbon monoxide and nitric oxide emissions are also predicted. Experiments have been conducted on a single cylinder, air-cooled, four-stroke, spark-ignited engine. In this work, by varying inlet valve closure timing (IVCT) and clearance volume, geometric expansion ratio (GER) of engine alone is varied, while effective compression ratio (ECR) is kept constant, thereby GER/ECR ratio is altered. For modified engine, GER/ECR ratio is varied from 1.25 to 2. Experiments have been conducted for two effective compression ratios, viz., 7 and 8 at a speed of 1200 rpm. Performance and exhaust emission characteristics have been measured at different loads and GER/ECR ratios. The predicted performance and emission characteristics are compared with measured values and the agreement between the two is found to be good. It is observed that, for modified engine, considerable improvements have been found in the reduction of pumping losses (about 25.8 to 56%), increase in the brake thermal efficiency (about 13.6 to 25%), and reduction in unburned hydrocarbon emissions (about 18.5 to 58%). Finally, for modified engine, it is found that GER/ECR ratio of 1.5 gives the best performance compared to standard engine for both compression ratios.

23 illus, 1 table, 41 ref

005742   Maiti K;Sil A (Dep of Metall and Mater Engng, Indian Inst of Technol, Roorkee-247 667, Email: asi11fmt@iitr.ernet.in ) : Preparation of rare earth oxide doped alumina ceramics, their hardness and fracture toughness determinations. Indian J Engng Mater Sci 2006, 13(5), 443-50.

Alumina based ceramics doped with rare earth oxide (Y₂O₃) of 500 ppm, 1000 ppm and 2000 ppm were prepared by following ceramic powder processing and solid state sintering at 1500°C for different soaking time periods of 3 h, 6 h and 9 h. Microstructural investigations on all the samples were carried out. Hardness measurements were conducted using Vickers Indentation technique. Fracture toughness of the samples was estimated by inducing radial cracks by various indentation loads on the samples. The measured hardness values were found to lie between 139 MPa and 1444 MPa, while the fracture toughness values lie in the range 1.65-5.76 MPa m^1/2.

8 illus, 2 tables, 11 ref

005741   Li Y;Hou B (Dep of Mar Corros, Inst of Ocenaology Chin Acad of Sci, Qingdao 266 071, P.R. China, Email: ytli98@163.com) : Corrosion fatigue of welded joints of steel for marine platform. Indian J Engng Mater Sci 2006, 13(5), 467-70.

Experiments on the corrosion fatigue behaviour of welded joints of the steel for marine platform in air and seawater, and of Tthe joints in seawater with cathodic protection, yielded data for linear regression to obtain fatigue life curves (ΔS-N_f). The laws of corrosion fatigue in welded joints of test steel are discussed with reference to those of A₅₈₇ and A₁₃₁ steel. In these experiments, the fatigue damage occurring at all welded joints around the weld interface resulted in the cracks and fractures. The fatigue life of the specimens in seawater with cathodic protection is longer than that in seawater without protection.

7 illus, 4 tables, 8 ref

005740   Leonavicius M;Krenevicius A;Suksta M;Stupak S;Bazaras Z (Dep of Strength of Mater, Vilnius Gediminas Tech Univ, Sauletekio ave 11, LT-10223 Vilnius, Lithuania, Email: marsu@fm.vtu.It) : Experimental and analytical investigation of loosening and shakedown of the threaded joints. Indian J Engng Mater Sci 2006, 13(5), 411-6.

In a tight threaded joint subjected to cyclic bending the regularities of crack formation and propagation possess specific features compared to joints subjected to the cyclic tension. The investigation results of tightening dependence on the number of cycles of threaded joints made of various steels show that a fatigue crack forms and propagates, plastic deformations develop or a structure element adapts oneself to a cyclic effect. In threaded joints subjected to tension and cyclic bending there is a link established between loosening and the fracturing process parameters such as the configuration and depth of crack. Due to such non-elastic deformation dangerous states may occur leading to deterioration of bolts. One of such states is characterised by a progressing accumulation of deformations resulting in the changes in the geometry of constructive elements. The approximate kinematic theorem has been used for the estimation of the bolt shakedown parameters in case of tension and bending.

5 illus, 14 ref

005739   Kumar V;Giri V K;Saxena S C (Dep of Electl Engng, Indian Inst of Technol, Roorkee-247 667) : Telemedicine in context to Indian health scenario. J Instn Engrs-Pt CP 2006, 87(May), 38-45.

An overview of the Indian health scenario and some of the on going projects in the area of telemedicine has beem presented. Recently, very serious efforts have been made to implement the tele monitoring projects by government, public and private sector organizations in India. The issues of the future integration of telemedicine activities within the national health service, that promises better access to health care with higher efficiency and mobility at lower cost, has been discussed. Though most of the on going telemedicine projects have been developed mainly for offline (store and forward) telemonitoring, some of them hold promise for their online/real time telemonitoring implementation in near future. The suitability of the systems has been overviewed for transmission control protocol (TCP), internet protocol (IP), local area network (LAN) and wide area network (WAN). The bandwidth, latency, availability, security and ubiquity, which are essential requirements and posing challenges in effective implementation of telemedicine projects, have also been discussed.

^iia2 illus, 3 tables, 28 ref

005738   Kumar N (Dep of Electl Engng, Delhi Coll of Engng, Delhi) : Development of a new scheme for damping torsional modes in a series compensated power system. J Instn Engrs-Pt EL 2006, 87(June), 23-8.

A new scheme for damping torsional modes in a series compensated power system has been developed. The proposed scheme utilizes the effectiveness of combined reactive power and frequency (CRPF) SVS auxiliary controller in co-ordination with an induction machine-damping unit (IMDU) coupled to the T-G. shaft. The studies are conducted on a system having a similar spread of torsional modes as the first IEEE benchmark model. The scheme stabilizes all the torisonal modes over a wide operating range of power transfer. SVS is installed at the middle of transmission line to optimize the power transfer capability. Also the optimal location of IMDU along the T-G shaft has been determined by performing eigenvalue analysis. It is found that locating IMDU after the IP turbine yields the maximum damping effect.

7 illus, 4 tables, 7 ref

005737   Kanchan P K;Nagabhushana M N;Nanda P K (NO, Cent Rd Res Inst, Mathura Road, New Delhi-110 020) : Overloading of commercial vehicles on Indian roads-two recent case studies. Indian Highw 2006, 34(1), 35-42.

14 illus, 7 tables, 6 ref

005736   Kamel M A;Satish Chandra;Praveen Kumar (Public Works Dep, Mansoura Univ, Mansoura, Egypt) : Modified AASHTO method for design of geogrid reinforced flexible pavements. Indian Highw 2006, 34(1), 49-55.

4 illus, 6 tables, 8 ref

005735   Jha S N;Chopra S (NO, Cent Inst of Post Harvest Engng and Technol, Ludhiana-141 004) : Selection of bricks and cooler pads for construction of evaporatively cooled storage structures. J Instn Engrs-Pt AG 2006, 87(June), 25-8.

Evaporative cooling is an efficient and economical means for reducing temperature and increasing the relative humidity of an enclosure, and has been extensively tried for enhancing the shelf life of horticultural produce. The evaporative cooled storage structure has proved to be useful for short term, on-farm storage of fruits and vegetables in hot and dry regions. Cooling performance of this structure depends on the construction materials used. The effect of various types of bricks and cooler pads on absorption and evaporation of water from their surfaces, at different ranges of temperature and relative humidity (RH) were studied to select the suitable one. The clay and sand lime brick and cooler pads made of 'partal' wood shavings were found to be most effective and economical for design of evaporatively cooled storage structures.

5 illus, 9 ref

005734   Janki Ram G D;Reddy A V;Rao K P;Reddy G M;Rao K P (Regional Cent for Military Airworthiness (Materials), , Kanchanbagh, Hyderabad, Email: jankiram_gabbita@yahoo.co.in) : Effect of magnetic arc oscillation on microstructure and properties of inconel 718 GTA welds. Trans Indian Inst Metals 2006, 59(1), 85-97.

In an effort to control Nb segregation and Laves formation in Inconel 718 gas tungsten arc welds, transverse magnetic arc oscillation was employed. At optimum arc oscillation conditions, considerable fusion zone microstructural refinement and reduction in interdendritic Nb segregation were achieved, with consequent reduction in the amount of Laves phase and improvement in its morphology. These improvements in weld microstructure were shown to result in significant improvement in weld tensile and stress rupture properties in direct aged condition. Use of post-weld solution treatment improved the weld properties to some extent in both unoscillated and oscillated welds, but the oscillated welds maintained their superiority over unoscillated welds in post-weld solution treated and aged condition also.

7 illus, 5 tables, 26 ref

005733   Jaja D T (Urban and Regional Plann Dep, Rivers St Univ of Sci and Technol, Port Harcourt, Nigeria) : Earth fill estimates in the planning of maintenance of earth roads ravaged by sheet erosion - case of Umuokoro road in Isiala Ngwa, Nigeria. Indian Highw 2006, 34(3), 37-44.

Umuokoro road is an earth road 1.75 km in length on a hilly terrain. It is subject to seasonal erosion annually as a result of seasonal rains, surface run off and soil wash. Quantified actual volume of fill required to replenish soil wash losses to effect maintenance. Precipitation data was sourced and obtained from Nigeria Metrological Services. Road length and gradients of surface profile were obtained from taping and running an open traverse survey witgh leveling insgtruments. Seasonal soil wash losses were quantified with Universal Soil Loss Equation, field survey and precipitation data as variables. Volume of soil lost to erosion signifies fairly and accurately, volume of material required in fill replenishment.

8 tables, 14 ref

005732   Jain N S;Kamlesh Kumar;Mishra D (Ministry of Shipp Rd Transp & Highw Dep of Rd Transp & Highw Dept of R, , New Delhi) : Development of road safety audit methodology for existing roadway sections and preparation of road safety audit manual. Indian Highw 2006, 34(2), 69-72.

005731   Jagtap R N;Ambre A H (Dep of Polym Engng and Technol, Inst of Chem Technol (UICT) Univ of Mumbai, Matunga, Mumbai-400 019, Email: jagtap_68@yahoo.com) : Overview literature on atomic force microscopy (AFM): basics and its important applications for polymer characterization. Indian J Engng Mater Sci 2006, 13(4), 368-84.

Atomic force microscopy (AFM) is a relatively new technique used for the surface characterization of polymers. It is capable of producing images of a non-conducting polymer surface without any chemical etching or staining. The unique feature of this technique as compared to other microscopy techniques is that we can study the mechanical properties of the polymer surface and it also does not involve the use of electron beam radiation that damages the polymer surface. Describes the various applications of atomic force microscopy like evaluation of mechanical properties, determining the chemical composition, studying photo-oxidative degradation of polymers, measuring the surface adhesion forces, studying the thermal phase transitions in polymers and determining the molecular weight and polydispersity index of polymer brushes. These applications have been elucidated with suitable examples.

14 illus, 2 tables, 75 ref

005730   Hongliang G;Guoming Y (Mechanical Engng Coll, Donghua Univ, Shanghai, China-200 051, Email: ghl0407@sohu.com) : A novel motion regulation of the heald frame on looms. Indian J Fibre Text Res 2006, 31(3), 467-9.

Eight-order polynomial motion has been proposed which optimizes the heald frame's dynamical performances. Compared to the simple harmonic and 7-order polynomial motion regulations, this motion regulation is proved to be more advantageous. The motion regulation improves the dynamic performance of heald frame. It is found to be suitable for high speed looms.

^ssc1 illus, 1 table, 4 ref

005729   Gupta V P (NO, , Badaun Pilibhit Circle, P.W.D., Bareilly-243 001) : Economic maintenance and improvement of bridges and culverts. Indian Highw 2006, 34(2), 13-28.

Adeaquate maintenance and improvement works of bridges and cultiverts are seldom done in Indian and other countries too. This is very necessary to avoid fast decay of service life and to avoid sudden collapses etc. often seen on roads, television and read in newspapers. Due to many reasons, repair of bridges and culverts get neglected a lot. Sudden failure, collapses closes the roads for years resulting intolerable inconvenience to the nearby population. All the narrow, weak and partially damaged even fully damaged, bridges and culverts can be rehabilitated, strengthened and widened to the required, anticipated traffic using available parts of doundation, piers, abutments and superstructure etc., as already done in a lot of bridges and culverts in the past. Timely maintenances and improvement works of bridges and culverts shall result in huge saving at national level, whose utilization shall result in construction of many more needed roads, bridges and culverts which shall be the real engineering skill. Various rational approaches, suggestions and illustrations to achieve manifold economy in maintenance and improvement works of bridges and culverts requiring dedication and determination has been presented.

11 photos, 18 ref

005728   Gupta P K;Pagalthivarthi K V (Dep of Mechanical Engng, MVGR Coll of Engng, Vizianagaram, Email: kvp@am.iitd.ernet.in) : Comparative study of the effect of model lift coefficients on particle trajectory. Indian J Engng Mater Sci 2006, 13(4), 293-306.

Objective of the present work is to (i) study the influence of different model lift coefficients, (ii) evaluate the importance of particle rotation, and (iii) compare the present computed results with two-way coupling results (in open literature) on the particle trajectory in dilute two-phase gas-solid horizontal channel flow. A hybrid Eulerian-Lagrangian method is employed where the Reynolds averaged Navier-Stokes (RANS) equations with k-<101> closure are used to model the fluid phase, and the particulate phase is treated via Lagrangian approach. Particle-wall collision is modeled using impulse-momentum equations. Five different models of lift coefficients (and/or lift forces) are selected from the open literature to evaluate the influence of lift force on the particle. The effect of shear lift is relatively very small as compared to lift due to particle rotation. Particle rotational velocities of the order of magnitude as high as 10⁴-10⁵ rad/s are encountered due to particle-wall collision. Results of computed particle trajectories with simplified assumptions agree closely with (i) the simulated results of FLUENT® (Version 6.1) with one-way and two-way coupling, and (ii) of other authors using two-way coupling. In terms of particle lift (and trajectory), the simulated results of FLUENT® with one-way coupling are in agreement with the literature than two-way coupling.

14 illus, 3 tables, 26 ref

005727   Gnanadass R;Venkatesh P;Palanivelu T G;Padhy N P (Dep of EEE, Pondichery Engng Coll, Pondichery-605 014) : Assessment of available and economic transfer capability for practical power systems with capacity benefit and transmission reliabilty margins. J Instn Engrs-Pt EL 2006, 87(June), 19-22.

Assessment of available and economic transfer capability with capacity benefit and transmission reliability margins of practical power systems in deregulated environment has been described. It is a measure of unutilized capability of transmission system subjected to wheeling transactions without violating transmission constraints at given time and load. Capacity benefit margin is incorporated by reserving powers in five transmission lines. The transmission reliability margin is implemented by making any one of the transmission lines as out of order at a time. The calculation of economic transfer capability (ETC) with margins that allows the feasible transactions without affecting utilities economy and network constraints in deregulated environment has been proposed. Optimal generation and cost of generating units have been evaluated using evolutionary programming without violating transmission constraints, which has been tested using Newton Raphson power flow algorithm. The proposed computation procedure of transfer capabilities with margins has been tested and analysed on IEEE-30 bus system. Simultaneous bilateral and multilateral wheeling transactions have been carried out in the test system for the assessment of available transfer capability (ATC). The solutions obtained are quite encouraging and useful in the present deregulated environment.

2 illus, 1 table, 18 ref

005726   Giriraj B;Raja V Prabhu Raja;Gandhinadhan R; Ganeshkumar R (Dep of Mechanical Engng, PSG Coll of Technol, Coimbatore-641 004, Email: giri_4656@yahoo.com) : Prediction of tool wear in high speed machining using acoustic emission technique and neural network. Indian J Engng Mater Sci 2006, 13(4), 275-80.

High speed machining (HSM) provides a lot of perks like higher productivity, better surface finish and good accuracy but with the limitation of rapid tool wear rate. On-line tool wear monitoring is therefore essential lor a fully automated high speed machining process. Acoustic emission (AE) technique has proven to be a better tool wear monitoring method owing to its sensitivity, quick response time and consistency. This work deals with the formulation of methodology and conduct experiments for predicting the tool wear in high speed machining using acoustic emission technique and artificial neural network (ANN). Taguchi's design of experiments has been used to optimize the number of experiment. The experimental observations are used to train an artificial neural network to predict the progressive tool wear. The outcome of the work includes the selection of optimum cutting parameters for minimum tool wear, identification of the percentage contribution of individual parameters towards tool wear and the prediction of tool wear using artificial neural network with a maximum deviation of 4%.

5 illus, 7 tables, 9 ref

005725   Edalati K;Akhlaghi F;Edalati A (Dep of NDT Nuclear Saf and Radiat Prot Technological Cent, AEOI, Tehran, P.O. Box: 14155 1399, Iran, Email: Edalatik@yahoo.com.au) : Influence of SiC and FeSi as silicon carriers on the characteristics of gray cast iron. Trans Indian Inst Metals 2006, 59(1), 65-72.

The Influence of silicon carbide and ferrosilicon as silicon sources on the cooling curve, microstructure and chill depth of hypoeutectic gray cast irons in different holding times, pouring temperatures and carbon equivalents has been studied. It is concluded that addition of SiC to the melt resulted in increased temperature of austenite formation and eutectic transformation. Results of microstructural studies revealed that SiC addition resulted in a more uniform distribution of type A graphite and refined eutectic cells and has little effect on graphite size. These observations were attributed to the pre-inoculation behavior of SiC in gray cast iron. Also for SiC treated cast irons with carbon equivalents higher than 3.7%, decreased hardness and chill depth were observed. The graphitization potential of SiC treated cast irons showed higher carbon equivalents as compared with FeSi treated cast iorn metals.

9 illus, 3 tables, 18 ref

005724   Dutta S K;Sah R (NO, , , Email: skdmet@yahoo.com) : Smelting Reduction Technologies. Trans Indian Inst Metals 2006, 59(1), 17-38.

For the past hundred years or so blast furnaces (BF) have played a major role in producing pig iron because of their high efficiency, mass production, and high degree of gas utilization. Blast furnace ironmaking is still the dominant process for the production of iron from ore. Such a long and sustainable track record arises out of continuous development in design, intensification of process technology, state-of-art instrumentation and control system including artificial intelligence system. But its dependence on metallurgical coal and prepared burden has driven steelmakers worldwide to look for alternative processes to avoid dependence on scarce metallurgical coal and reduce process steps like cokemaking and agglomeration, to minimize capital investment involved and reduce harmful impact on environment. Smelting reduction (SR) technologies are coming up to offer such alternatives to blast furnace ironmaking. With a comprehensive review of various promising smelting reduction (SR) processes, their development and present status. It also discusses about the characteristics of foaming slag, foaming index and form life.

^iia7 illus, 3 tables, 55 ref

005723   Dua A;Sarkar P K;Choudhry S (Sch of Plann and Architecture, , New Delhi) : Traffic diversion scheme during construction of Delhi metro at Connaught Place Area, New Delhi. Indian Highw 2006, 34(3), 23-35.

Study was undertaken to workout a traffic diversion scheme as a part of traffic management plant at Connaught Place area keeping in view the closure of the radial road 4 during the construction of North-South corridor of Metro System. After having conducted a detailed reconnaissance survey coupled with a collection of primary data, nature and magnitude of traffic flow in the one-way pattern of Connaught Place road network was assessed. In order to prepare a feasible traffic diversion plan in contest of closure of radial road 4, five alternative proposals were worked out and evaluated after simulating the traffic on road network. Finally alternative proposal-I proved to be feasible and implementable as compared to the other alternative proposals.

8 illus, 4 tables, 2 ref

005722   Daunys M;Taraskevicius A (NO, Kaunas Univ of Technol, Kestucio 27, Kaunas, 44025, Lithuania, Email: mykolas.daunys@mf.ktu.It) : Investigation of low cycle fatigue crack opening size and closure stress. Indian J Engng Mater Sci 2006, 13(5), 417-25.

In the recent years, a number of studies on the fatigue crack opening and crack closure load have been carried out. Investigation serves as an intermediate point to complete a failure prediction model with a more practical value for determination of leak before the break (LBB) problem in pressure vessels and pipes. An attempt has been made to solve this problem by using analytical, numerical and experimental methods. Method of linear fracture mechanics at analytical investigation by using the analogy between the stress strain state at stress concentrator and the crack tip and strain intensity factor is adapted to the nominal elastic-plastic loading. Investigation has showed that numerical results are in good agreement with the experimental results. However, the proposed analytical model satisfactorily matches with the experiment in the middle of the crack, which is acceptable for LBB conception, and incorrect at the crack tip, which is non-acceptable for the fracture mechanics conception.

10 illus, 8 ref

005721   Das S S;Srivastava V;Singh P (Dep of Chem, D D U Gorakhpur Univ, Gorakhpur-273 009, Email: ssdas2002@rediffmail.com) : Ionic transport in sodium phosphate glasses doped with chlorides of Co, Cd and Ag. Indian J Engng Mater Sci 2006, 13(5), 455-61.

Several samples of sodium phosphate glasses doped with different concentrations of chlorides of cadmium and cobalt along with samples of undoped sodium phosphate glass have been prepared. Sodium phosphate glasses doped with varying amounts of AgCl have also been prepared to see the role of Ag⁺ ion in modifying the conductivity of sodium phosphate glass. These glasses have been characterized by elemental analysis, X-ray diffraction, IR spectra, differential scanning calorimetry, transference number measurements and electrical conductivity studies. All the glasses are found to be essentially ionic conductors. The undoped sodium phosphate glass has low σ value in comparison to the doped ones. The values of ionic conductivity in Na₂O-P₂O₅-CdCl₂ and Na₂O-P₂O₅-CoCl₂ glasses are maximum for 1% CdCl₂ and 5% CoCl₂ doped ones respectively. However, in the case of Na₂O-P₂O₅-AgCl glass the σ values go on increasing with the increasing concentrations of the dopant AgCI and the following sequence is observed. σ (-CdCl₂)<60>σ (-AgCl) result have been explained on the basis of changes in the structure of sodium phosphate glass matirx by the addition of different dopant cations, viz; Cd²⁺, Co²⁺ and Ag⁺.

2 illus, 2 tables, 47 ref

005720   Das J K;Chowdhury S P;Chowdhury S;Choudhuri S (Damodar Valley Corporation (DVC), , Kolkata-700 054) : A knowledge based study of over voltages during restoration of a real utility. J Instn Engrs-Pt EL 2006, 87(June), 47-52.

Steady state and transient models of transmission lines at different voltage levels to simulate the over voltages during initial switching operations has been described. Simulation of resonance over voltages which may occur during initial system build-up stage has also been done with the help of EMTP model of 3ε dc transmission lines. A knowledge base termed as over voltage knowledge base (OVKB) is formed with the results obtained from simulation studies of different kinds of over voltages for a real utility. OVKB records are used to help the operating engineers for selecting proper switching paths during actual restoration operations.

11 illus, 1 table, 6 ref

005719   Das D;Kaimal K N G (Div of Chem, Bhabha Atom Res Cent Trombay, Mumbai-400 085, Email: dasd@barc.gov.in) : Release behavior of gaseous and volatile fission products in irradiated thoria based fuel materials. Metals Mater Process 2006, 18(1), 47-52.

Transport behaviors of the gaseous, and volatile fission product species, xenon, iodine and tellurium in thoria and urania based fuels are presented. The high temperature (1000-1800K) transport coefficients of Xe, I, and Te derived from the results of post irradiation annealing study on the trace-irradiated samples of high grain density are compared for the two types of fuel matrices. The transport kinetics of Xe, I, and Te are found to be drastically low in thoria as compared those in urania. The results are discussed considering the nature of fuel matrix and the transporting species.

6 illus, 2 tables, 8 ref

005718   Chaudhary R R;Pradeep Kumar;Sri Chand (Dep of Chem Engng, Indian Inst of Technol Roorkee, Roorkee-247 667) : Catalytic wet air oxidation of toxic nitrogen containing compounds (pyridine) from wastewater. J scient ind Res 2006, 65(9), 757-9.

Cu-Co/C (heterogeneous) and CuSO₄ (homogeneous) were used as calalysts for wet air oxidation to remove nitrogen containing toxic organic compounds from wastewater. For this purpose, a model compound, pyridine, was treated in a high-pressure batch autoclave at mild conditions of temperature and pressure. Copper and cobalt are relatively inexpensive catalytic material and have shown higher conversion efficiencies. Both CuSO₄ and Cu-Co/C have optimum activity at an initial pH 4 of the pyridine solution. After 2 h of reaction time, % conversion with CuSO₄ (75.1 %) was more in comparison to Cu-Co/C (71.8%) using 5 mg/l catalyst concentration at 160°C and 9 bar total pressure.

5 illus, 6 ref

005717   Chakraborty P S;Majumder G;Sarkar B (Dep of Adult Continuing Educ and Ext, Jadavpur Univ, Kolkata-700 032, Email: p_s_c2001@yahoo.com) : An approach to manage constraint resource and outsourcing decision. J scient ind Res 2006, 65(8), 625-31.

Constrained resources in manufacturing organization lead managers to take decision on outsourcing of some products. Compares the possible solution between normal accounting, theory of constraints (TOC) and extended TOC to decide production outsourcing. This paper is a real life implementation of linear programming with TOC philosophy, which is easier to follow with very few parameters required for verification. Extended TOC model is simple and helps managers to make faster decision in outsourcing problem with maximum throughput.

2 illus, 7 tables, 17 ref

005716   Cengiz A;Ucar M (Dep Mechanical Educ, Sch of Tech Educ Kocaeli Univ, 41100 Kocaeli, Turkey, Email: ucarm@kou.edu.tr ) : Determination of the effect of temperature and relative humidity on the friction coefficient of V-belt mechanism. Indian J Engng Mater Sci 2006, 13(5), 405-10.

In the V-belt drive system, temperature and humidity are the most effective parameters affecting the slippage. This study is done in two stages. Firstly, experimently study has been carried out and the effect of temperature, relative humidity on the slippage between V-belt and pulley has been analyzed. At the second stage, non-linear regression analysis has been carried out to get a prediction equation for edtermining of friction foefficient gbetween V-belt and pulley at the different temperature and humidity. In the analysis MATLAB Statistics Toolbox was used. At the result of the analysis the prediction equation has been obtained with 0.995 correlation coefficient. It has been that invrease of temperature and humidity leads to decrease in the coefficient of friction (slippage raises). In high humidity conditions, slip quantity rapidly when temperature is 60-80°C.

2 illus, 3 tables, 11 ref

005715   Bhosale S S;Mandal J N (Civ Engingerring Dep, IIT Bombay, Mumbai, Email: ssbhosale@iitb.ac.in) : Reflection cracking on asphalt overlays. Indian Highw 2006, 34(3), 11-22.

^iia7 illus, 69 ref

005714   Bhim Singh;Singh B P;Dwivedi S (Dep of Electl Engng, IIT Delhi Hauz Khas, New Delhi-110 016) : A state of art on different configurations of permanent magnet brushless machines. J Instn Engrs-Pt EL 2006, 87(June), 63-73.

Highest efficiency, fast dynamic response and high power density of permanent magnet brushless (PMBL) machines are resulting in their wide spread applications. There are various type of these machines including permanent magnet synchronous motors (PMSM), permanent magnet brushless dc motors (PMBLDM) and hybrid doubly salient motors. A comprehensive review of different configurations of PMBL machines, their rotor geometries and application potential, state of art and recent trends in PMBL machines. A classified list of more than one hundred research publications on the subject is appended for quick reference.

28 illus, 2 tables, 126 ref

005713   Bharat Singh (Wat Resour Dev Training Cent, Indian Inst of Technol, Roorkee, Uttaranchal) : An attempt to assess the water requirements and availability in the area between river Sutlej and Yamuna. Wat Energy int 2006, 63(3), 29-31.

Recently the problem of water distribution in the Punjab-Haryana area has been attracting country wide attention. The problem has been reviewed and discussed primarily from legal and constitutional view point. Claims about water need have been made qualitatively and severe shortages, present or anticipated, claimed without furnishing substantive proofs. An attempt is being made to look at the problem from a professional, water resource engineer point of view, though, it is realized that final decision has to be in consonance with the legal position and also acceptable to the Governments and people of the two States.

1 table, 2 ref

005712   Bharasi N S;Shaikh H;Venugopal S;Parida F C; Kannan S E;Khatak H S (Div of Corros Sci and Technol, Indira Gandhi Cent for Atom Res, Kalpakkam-603 102, Email: hasan@igcar.ernet.in) : Assessment of material damage due to sodium fire. Trans Indian Inst Metals 2006, 59(1), 139-47.

This work details the effect of sodium fire on the microstructural stability, corrosion behaviour and mechanical properties of mild steel (MS). In the two test runs liquid sodium of 5.5 kgs (test run I) and 15 kgs (test run II) inventories were dumped into two different MS test trays. Measurements of corrosion rate indicated high corrosion rates which doubled from 47 μm.h^-1 (16668 mpy) in test run I to 101 μm.h^-1 (33375 mpy) in test run II. Microstructural and X-ray diffraction (XRD) examination revealed that the ferrite + carbide microstructure remained stable with no other precipitates forming during the reheating of MS. Significant increase in grain size of MS was observed on exposure to sodium fire in test run II. Mechanical properties evaluation indicated no change in hardness, ductility and ultimate tensile strength (UTS). However, significant drop in upper and lower yield points was observed on exposure to test run II.

4 illus, 6 tables, 13 ref

005711   Basu M;Chattopadhyay P K;Chakrabarti R N; Ghoshal T K (Dep of Electl Engng, Jadavpur Univ, Kolkata 700 032) : Economic emission load dispatch with non-smooth fuel cost and emission level functions through an interactive fuzzy satisfying method and evolutionary programming technique. J Instn Engrs-Pt EL 2006, 87(June), 41-6.

Evolutionary programming based fuzzy satisfying method for solving economic emission load dispatch problem with non-smooth fuel cost an emission level functions has been presented. The problem treats economic and emission as competing objectives for optimal dispatch, which requires some form of conflict resolution to arrive at a solution. Assuming that the decision maker (DM) has imprecise or fuzy goals for each of the objective functions, the multiobjective problem is transformed into a minimax problem, which is then handled by the evolutionary programming technique. The solution methodology can offer a global or near-global non-inferior solution for the DM. Numerical results for a sample test system have been presented to demonstrate the performance and applicability of the proposed method.

2 illus, 4 tables, 21 ref

005710   Basu M;Chakrabarti R N;Chattopadhyay P K; Ghoshal T K (Dep of Electl Engng, Jadavpur Univ, Kolkata 700 032) : Simulated annealing based optimal long term scheduling of variable head multi reservoir power system. J Instn Engrs-Pt EL 2006, 87(June), 35-40.

A method for optimal long-term scheduling of a hydro-power system based on simulated annealing technique has been presented. The proposed method maximizes total expected benefits, ie, benefits from energy generated by a hydro-power system over the planning horizon plus the expected benefit from the water left in storage at the end of that period while taking into account the stochasticity of the river inflows and satisfying the various constraints such as environmental, physical, legal, contractual constraints etc. The algorithm is demonstrated by its application to a test system. The results obtained have been compared to those found by linear and dynamic programming method.

1 illus, 6 tables, 17 ref

005709   BaskaranA;Narayanasamy R (Production Engng Dep, Natn Inst of Technol, Tiruchirappalli-620 015, Email: narayan@nitt.edu) : Effect of various stress ratio parameters on cold upset forging of irregular shaped billets using white grease as lubricant. Indian J Engng Mater Sci 2006, 13(4), 281-92.

To investigate the effect of various stress ratio parameters on cold upset forging of commercially pure aluminium solid billets of irregular shaped billets using white grease as lubricant applied on both sides. Samples with two different aspect ratios (ratio of height to diameter) namely, 0.5, 0.75 and 1.0 with different bla ratios (ratio of minor to major diameter) namely 0.6 and 0.7 were prepared and cold forged. Cold deformation experiments were carried out in an incremental step and at the end of each step, dimensions such as height, contact and bulged diameters being measured. The calculations were made with the assumption that the radius of curvature of the barrel followed the form of a circular arc. Analysis of the experimental data showed that there exists a relationship between the measured barrel radiys and various stress ratio parameters namely, (F128><115>₀/(F128><115>_z), ((F128><115>_m/(F128><115>_z), ((F128><115>_eff/(F128><115>_z), and ((F128><115>_m/(F128><115>_eff) developed under plane stress condition. An attempt has also been made to relate the percentage height reduction with respect to the stress ratio parameters namely, (F128><115>₀/(F128><115>_z), ((F128><115>_m/(F128><115>_z), ((F128><115>_eff/(F128><115>_z), and ((F128><115>_m/(F128><115>_eff) developed under plane stress condition and found to have an increasing trend with enhanced level of deformation.

13 illus, 16 ref

005708   Banerjee S;Sah D N (Div of Post Irradiation Examination, Bhabha Atom Res Cent, Mumbai-400 085, Email: sup@barc.gov.in ) : Safety studies on PHWR fuel pin. Metals Mater Process 2006, 18(1), 85-94.

Oxidation of zircaloy fuel cladding by steam during a postulated loss of coolant accident (LOCA), may lead to its embrittlement and failure. Therefore preserving the mechanical integrity of cladding during such events is a reactor-licensing requirement from safety point of view. However the behavior of fuel during postulated LOCA conditions is not fully understood and little or no experimental data is available on Indian pressurized heavy water reactor (PHWR) fuel pins. Safety assessment relies heavily on codes, which use excessive conservatism to cover the unknown factors. Therefore, the availability of experimental database can significantly reduce such uncertainties associated with the existing codes and define design limits, and the fuel failure criteria. Keeping this necessity in view, a steam oxidation facility is being developed. In the mean time, initial experiments have been conducted in air on some fuel pins to study the effect of severe oxidation. Leistikow et.al. carried out oxidation of zircaloy-4 in pure nitrogen, oxygen and air in the temperature range 900-1150°C.

9 illus, 1 table, 3 ref

005707   Bakshi S;Chattopadhyay K;Kumar S (Dep of Metal, Indian Inst of Sci, Bangalore-560 012) : Novel technique of processing functionality graded material in age-hardenable Al-alloys. Trans Indian Inst Metals 2006, 59(1), 73-84.

New processing route for establishing functional property gradient in age-hardenable Al-alloy systems is devised and the feasibility of this process route is demonstrated. Two age-hardenable Al-alloys, namely, Al-5Zn-1Mg and Al-4.6Cu alloys are used as model alloy systems. The processing method involves producing a microstructural gradient in the initial homogeneous material without altering the composition of the bulk. Transmission electron microscopic studies at different layers of FGMs confirm the evolution of graded microstructure across the specimen cross-section. The established microstructural gradient in the material leads to a property gradient in terms of hardness and thereby yield strength for both the alloy systems, which is confirmed through hardness measurements.

15 illus, 1 table, 11 ref

005706   Atre A A;Kumar V (Dr. A.S. Coll of Agric Engng, M P K V, Rahuri-413 722) : Innovation diffusion model for real time stream flow forecasting. J Instn Engrs-Pt AG 2006, 87(June), 16-18.

An innovation diffusion model for forecasting number of adopters of a new product, with internal and external influence was presented by Bass. An analogy of innovation diffusion with stream flow has been presented along with the procedure, developed for k-day ahead forecasts of cumulative stream flow. The daily stream flow data of Godavari river at Gangapur dam site for 21 years (1979-1999) were used for application of the developed model for 1 day to 6-day ahead forecasts of cumulative and daily stream flow. The performance of the model was tested using seven different statistical indices. The coefficient of efficiency for the model ranged from 0.9866 to 0.9994 indicating that the model is highly acceptabte. The model needs estimation of only three parameters and the forecasting does not need complicated computing procedure, besides the advantage of updating forecasts as new data become available.

2 tables, 10 ref

005705   Arya L D;Titare L S;Choube S C (Dep of Electl Engng, S G S I T S, Indore, M P) : Voltage security monitoring and control using back propagation algorithm based artificial neural networks. J Instn Engrs-Pt EL 2006, 87(June), 29-34.

A technique for obtaining settings of PV-buses so as to maintain desired level of security has been described. Desired level of voltage security has been maintained using a probabilistic insecurity index (PISI) based on voltage stability consideration. A back propagation algorithm (BPA) based network is trained to represent the system as ANN model. This model for any operating condition gives the value of insecurity index. Using this network, another network is trained to give the settings of PV-buses so as to have a threshold value of probabilistic insecurity index. This second network is known as controller network. Controller network has been obtained for a standard IEEE 6- bus, 7-line test system.

4 illus, 4 tables, 14 ref

005704   Ansari M S;Singh B;Navathe C P (High Pwr Laser Electron Lab, Raja Ramana Cent for Advd Technol, Indore-452 013, Email: msa@cat.ernet.in) : Low jitter variable delay generator for regenerative amplifier in a table top terawatt femto second laser system. Indian J Engng Mater Sci 2006, 13(4), 269-74.

Describes the design and development of a pulse selector circuit, two different low cost techniques for generation of low jitter variable delays and a high band width line driver for use in the regenerative amplifier stage of a table top Terawatt femto second laser chain. The pulse selector stage selects one pulse from a high frequency laser oscillator, injects it into the regenerative amplifier and ejects it after a preset delay. Two different schemes for the delay generator described here are based on the IC AD 9501 and ECL mono shots. These can provide variable delay in the range of 2.5-800 ns. Jitter in the set delay for the circuit based on ECL mono shot is found to be 800 ps. Whereas, jitter for the circuit based on AD9501 is dependent on the set delay and varies between 500 ps to 2.2 ns over the entire delay range of 2.5-800 ns.

7 illus, 5 ref

005703   Albert S K;Matsui M;Watanabe T;Hongo H;Kubo K;Tabuchi M (Mater Joining Sect Indira Gandhi Cent for Atom Res, , Kalpakkam-603 102, Email: shaju@igcar.ernet.in) : Creep behaviour of weld joints and simulated HAZs of a high Cr ferritic steel. Trans Indian Inst Metals 2006, 59(1), 47-55.

Creep tests were carried out on 11Cr-0.5Mo-2WCuVNb steel weld joints and simulated HAZs produced by heat treatment and using a weld simulator. For weld joints, the fracture occurred in the fine grained heat affected zone (FGHAZ); with rupture life considerably lower than that of the base metal. Rupture life was found to depend on width of HAZ and groove angle of the weld joint. HAZ specimens simulated by heat treatment had uniform microstructure. Their creep properties varied widely with temperature of simulation and creep strength was minimum for simulation temperatures corresponding to fine grained HAZ (FGHAZ) in a weld joint. In general, the rupture life of the simulated FGHAZ was found to be lower than that of the weld joint. For HAZ simulation by weld simulator, simulation temperature was uniform only for short length at the center of the specimen and hence, the microstructure of the specimen varied along its length and fracture of the specimen during creep testing occurred at the fine grained zone formed in the specimen during simulation. Rupture life did not vary much with the simulation temperature; it was close to that obtained for FGHAZ specimen simulate by heat treatment. Multiaxial stress state formed in the weld joint during testing due to existance of different HAZs, base metal and weld metal, which very widely in their properties appears to affect the fracture behaviour of the weld joints in addition to the low creep strenth of the FGHAZ. As the stress state is altered by the HAZ width and groove angle, these parameters also influence the rupture life of the weld joint.

10 illus, 2 tables, 15 ref

005702   Akbas A;Ergun M (Vocational Sch of Tech Sci, Marmara Univ 34722 Goztepe-Kadikoy, Istanbul, Turkey, Email: mergun@ins.itu.edu.tr) : Freeway traffic flow control by lumped parameter system approach. Indian J Engng Mater Sci 2006, 13(4), 322-32.

Freeway traffic flows can be controlled by lumped parameter system approach owing to the space discretized system models. Such a control model incorporating a coordinated ramp metering mechanism is proposed in this study. The nonlinear state equations representing the traffic system dynamics are derived from the conservation law in difference equations form. The control model is obtained by a feedback linearization approach, so that the target density of the controller is chosen as the critical density of the traffic system. Simulation based test studies have been done in a VISSIM simulation environment in order to compare the data obtained by the shock wave modified feedback linearization method to the non-modified type, with respect to the uncontrolled system performance. Test results show that the main-link flow performance is increased sufficiently by the proposed control model.

14 illus, 15 ref

005701   Aisien F A;Hymore F K;Ebewele R O (Dep of Chem Engng, Univ of Benin, Benin City, Nigeria, Email: afaisien2002@yahoo.com) : Application of ground scrap tyre rubbers in asphalt concrete pavements. Indian J Engng Mater Sci 2006, 13(4), 333-8.

Laboratory scale evaluation of the feasibility of using ground rubber from scrap tyres in dry process hot-mix asphalt concrete used for road pavement was investigated. The rubber to asphalt ratio (by weight) of the specimens that was initially kept constant at 0.2 was subsequently varied from 0.1 to 0.5 using different rubber particle sizes. Some specimens were cured at ambient temperature, while others were soaked in water inside a curing tank, for a period of 28-days in the laboratory. The Marshall method was used to prepare both conventional and rubberized asphalt concrete specimens. The indirect tensile testing machine was used in the measurements of mechanical properties of all specimens. The results from the study show that the rubberized asphalt concrete mix has much better mechanical properties than the conventional one: the tensile strength of the specimens for example, increased from 1.82 x 10³ to 2.04 x 10³ kPa as the rubber to asphalt ratio increased from 0.1 to 0.3. Similar trends were observed in compressive and tensile moduli. The mechanical properties of rubberized specimens cured in air and those soaked in water were not significantly different (P<62>0.05). However, the conventional concrete especially those soaked in water showed inferior mechanical properties. The rubber particle size of 0.60 mm had the best mechanical properties while that of particle size 2.36 mm has the poorest mechanical properties.

6 illus, 3 tables, 24 ref

005700   Ahmed K S;Vijayarangan S (Dep of Production Engng, PSG Coll of Technol, Coimbatore-641 004, Email: sabil_k@yahoo.com ) : Elastic property evaluation of jute glass fibre hybrid composite using experimental and CLT approach. Indian J Engng Mater Sci 2006, 13(5), 435-42.

Elastic properties are the basic quantities that are required during design and optimization of a laminated structure. Though the literature on elastic properties of conventional single fibre composite is well published, the same is scanty in the case of natural and hybrid composites. This work is focused on evaluation of in-plane elastic properties of untreated woven jute and jute-glass fabric hybrid polyester composites, under tension. The specimens have been fabricated by hand-lay-up technique with different relative weight fraction of jute and glass fibre. Theoretically, the laminate elastic properties are predicted by using the classical lamination theory CLT and rule of hybrid mixture model. using the resin and fibre properties together with the volume fraction (micromechanics). Experimentally, the elastic properties have been evaluated by tension test in warp and weft direction and in-plane shear test as per ASTM standards. The results indicated that the Young's modulus in both warp and weft direction improve by the inclusion of glass fibre, where as Poisson's ratio is decreased. Prediction by CLT and model showed, close agreement with experimental values with a maximum deviation of about 20%. The possible causes for this deviation are discussed.

6 illus, 4 tables, 20 ref

005699   Agarwal R K;Jain S K;Panday P K (Steel Auth of India Limited Bhilai Steel Pl, , Bhilai-490 001, Email: bitdurg@sancharnet.in) : Destruction of polychlorinated biphenyl and utilization of waste heat in integrated steel plant. J scient ind Res 2006, 65(9), 753-6.

Hazardous waste management has become a matter of international priority. Use of polychlorinated biphenyl (PCB) as dielectric fluids in transformers and capacitors has been banned owing to its toxic hazards. Further, at 300-800°C, it can produce even more toxic compounds (polychlorinated dibezodioxins and dibenzofurans). Nonexistence of any viable disposal technology has resulted in huge stockpiles of PCB contaminated oil at various Indian industries. Reports destruction technology trial to destroy PCB by incineration in rotary kiln. This field trial was succesful in destroying PCB and utilizing generated heal energy for dolomite and limestone calcination. This hazardous waste was destructively utilized as fuel supplement during controlled incineration limiting stack emission within stipulated norms.

1 illus, 1 table, 9 ref

005698   Abraham M;Pulavendran S;Ramanujam A (NO, Cent Leath Res Inst, Adyar, Chennai-600 020) : Effect of lipid on protein degradation during anaerobic digestion. Indian J envir Prot 2006, 26(7), 599-609.

Inhibition effects of lipid on protein degradation during anaerobic digestion were extensively studied in bench scale reactor with different ratios of protein and lipid. Bench scale reactor with the working volume of 2.1L was used for the experiments. The different ratios of protein and lipid such as 70:30%, 80:20%, 90:10% and 1000:00% were fed daily (once in a day) to the reactors inoculated with the anaerobic sludge treating animal glue solid wastes. The ration containing 90% protein and 10% lipid worked well and its daily biogas production rate was 0.75L, whereas in the other ratios containing more than 10% lipid and 100% protein alone resulted in the accumulation of total volatile fatty acids (TVFA) and decrease in pH and the daily gas production was less than 0.35L/d at the end of the study period. And also, when the lipid increased, the hydrolysis/acidogesis of protein was not affected whereas TVFA conversion was severely affected. Although ammonical nitrogen (NH⁺₄-N) was more than 8000 mg/L in all the experiments, ammonia toxicity was not happened because of the prevalence of pH below 7.4. The wastes containing more than 10% lipid for example, tanning, slaughterhouse and poultry industries need more attention about the inhibition effects of long chain fatty acids (LCFA) resulting from the hydrolysis of lipid during anaerobic digestion.

6 illus, 22 ref

004715   Vikram Kumar;Jain V K (Natn Phys Lab, , New Delhi-110 012) : Potentialities and economic challenges in the area of MEMS. Elect Inf Plann 2006, 33(7-8), 159-66.

8 illus

004714   Venkataramaiah P;Krishnaiah G (Dep of Mechanical Engng, Srikalahasteeswara Inst of Technol, SRIKALAHASTI-517644) : Dynamic modeling of turbine blade with friction damper and study of the resonant response of blade. Bull pure appl Sci-Sect D 2006, 25(1), 1-8.

Work deals with dynamic modeling of turbine blade with friction damper and study of the resonant response of blade. A mathematical model for the combined blade with damper system is developed and numerical simulations are performed using the MATLAB programs. The resonant response of the turbine blade is attenuated through the use of friction damper and it is studied by the simulation.

5 illus, 17 ref

004713   Vaidyanathan S;Venkatesh T N;Mohan N Krishna (Dep of Mechanical Engng, Annamalai Univ, Annamalai Nagar-608 002) : Isentropic swirling flow through supersonic nozzles-part I (Free vortex flow). J Aerospace Sci Technol 2006, 58(1), 38-49.

Analytical model has been developed and an approximate solution for the free vortex swirling supersonic flow through nozzles. Earlier work by Mager, is potential flow based. In the present model swirl number has been redefined to confine the flow properties within the valid range. Flow properties are always determined by the total conditions (P0 and a0), nozzle profile and swirl intensity as in the case of one-dimensional flow. Integral form of the continuity equation has been used in order to satisfy the boundary conditions, since radial velocity component is ignored. For free vortex case, it has been shown that there exists a minimum radius along the length of the nozzle at which the density is zero and flow seems to be void causing reasonable blockage to the flow at throat. In defining the non-dimensional swirl number (β), axial velocitv at each section was employed for non-dimensionalozation as compared to Mager's definition of using a global constant to find swirl number (α). The variations of performance parameters of the nozzle such as co-efficient of discharge (Cd) thrust efficiency (η_s) and impulse efficiency (η_l) and flow field parameters such as density, pressure, velocity etc. are presented as a function of swirl numbers (α, β) and compared with the available experimental data. The swirl numbers (<97>, <98> are also correlated.

11 illus, 29 ref