017467   Chaubey S (Physics Dep, Motilal Nehru National Institute of Technology, Allahabad-211 004, Email: chaubey55@yahoo.com) : Critical assessment of flory's approach for estimating miscibility gap in binary monotectic systems. Indian J Engng Mater Sci 2009, 16(5), 364-6.

Flory's solution approach, which gives expression for the free energy of mixing of binary alloys whose constituent atoms differ largely in size, has been used to find the required model parameters in terms of which expressions for critical temperature (T_c) and critical composition (X_c) have been derived. Model parameters are capable of describing the thermodynamic behavior of the liquid phase and are useful in constructing the miscibility gap in binary monotectics,. Within the limits fairly good agreement has been observed between theoretically calculated and experimentally observed values of X_c and T_c along with the reasonable data for the various thermodynamic functions at the desired temperature in four binary monotectic systems chosen for the present study.

1 illus, 10 ref

017466   Calik A;Taylan F;Sahin O;Ucar N (Mechanical Education Dep, Technical Education Faculty, Suleyman Demirel Univ, Isparta, Turkey, Email: nazmucar@yahoo.com) : Comparison of mechanical properties of boronized and vanadium carbide coated AISI 1040 steels. Indian J Engng Mater Sci 2009, 16(5), 326-30.

Comparison of mechanical properties of medium carbon steel AISI 1040 for vanadium carbide coated (VCC) and boronized conditions has been studied by means of microhardness, tensile and impact tests. For the treated steels, the boriding and vanadizing processes have been carried out in the same conditions, i.e., at a temperature of 1210 K for 4 h. The thickness of diffusion layer has been measured as 5 um and 100 μm for the VCC and the boronized steels, respectively. In laboratory conditions, the VCC steels show considerably higher strength and surface hardening with respect to the untreated and the boronized steels. At the same time, Charpy V-notch impact tests have also been carried out for the steels with and without surface hardening. It is concluded that coating is effective in improving the mechanical performance of AISI 1040 steels.

4 illus, 2 tables, 30 ref

017465   Bounazef M;El Abbas Adda bedia (Hydrology and Materials Laboratory, Sidi Bel Abbes Univ, Algeria) : Effect of the porous bentonite-AlCrNi material in the turbine efficiency preservation. Int J theor appl mech 2008, 3(2-3), 149-60.

In order to increase the turbine gas efficiency and its power, the clearances between rotaring blades and the interior casing should be as small as possible. To obtain that, one sprays a sacrificial material on the casing by the thermal blowtorch flame-powder process and one obtains a coating layer. During the blades rotation, they scrape the (Al₂O₃.4SiO₂.H₂O-Na-Ca-Mg)-AlCrNi coating and tear off a fine layer in small remains. It creates itself a functional gap between the blades and the casing seal. The combustion gases do not escape through the clearance, and contribute consequently in the power production. The aim of this work is to investigate the behaviour of a particular sacrificial material, the Bentonite-metallic phase and its effect on the turbine blades wear during inter-reaction between them under experimental conditions of operating rotor blades. For this purpose, we use a Sulzer Metco abradability test. To determine this problem, we carried out several tests by changing 4 functional parameters. They are the incursion speed within the seal coating, the linear blades speed, the blades depth incursion inside the casing seal and the operating temperature. The obtained results are shown in form of graphs and maps, and the comments explain when there is the blades wear or material transfer, and the different effects observed on the coating surface.

7 illus, 4 tables, 13 ref

017464   Baredar P;Sethi V K;Pandey M (NO, Laxmi Narain College of Technology, Bhopal, Email: prashant_baredar@yahoo.com) : Power productivity enhancement and reliability analysis using hybrid system of solar, wind and biomass. J Envir Res Dev 2007, 2(1), 70-5.

Every country has her dreams to become self-dependent in the power sector. Solar, wind and biomass energy can be encashed to fulfill the desired requirement of power supply. The whole world is trying for searching new means of power generation. In India the efforts are being done in this direction. Various sources of energies are utilized for producing electrical power being such as solar, wind and biomass. They are being used either independently or collectively. Day after new innovative ideas are being added to this field. For reliable supply of power in remote locations or inaccessible rural areas it will be possible and sometimes necessary to design and setup Hybrid system, which combines the advantages of two or more different technologies, to take care of base load requirements. An integrated Hybrid System Solar, Wind and Biomass would ensure that power supply could be maintained at an optimum level during adverse condition like cloudy days (for PV system), low wind conditions (for wind electric generators) and non-availability of Biomass in rainy season. An effort is made in this direction to obtain reliability analysis of proposed hybrid system.

3 illus, 1 table, 11 ref

017463   Bansal V;Bansal M C;Dhawan S K (Polymeric & Soft Materials Section, National Physical Laboratoy (CSIR), Dr K S Krishnan Road, New Delhi-110 012, Email: skdhawan@mail.nplindia.ernet.in) : Charge transport and ammonia sensing response in poly (aniline-co-1-amino-2-naphthol-4-sulphonic acid). Indian J Engng Mater Sci 2009, 16(5), 355-63.

Reports the synthesis of tubes of poly (aniline-co-1-amino-2-naphthol-4-sulphonic acid) using para toluene sulphonic acid as a dopant. The copolymers have the conductivity of the order of 0.348 S/cm to 0.198 S/cm depending on the ratio of the co-monomers present in the feed ratio. The morphology of the copolymers was studied by scanning electron microscope. Electrical conduction have been studied in the temperature range from 300 K to 30 K. Charge transport has been attributed as tunnelling in the range 30 K to 70 K. Above 70 K, charge transport is represented by Mott's three-dimensional variable hopping. The copolymer has been found to be a better ammonia vapour sensing material and can be used for detection for varying concentration.

8 illus, 1 table, 36 ref

017462   Bakwad K M;Pattnaik S S;Devi B S;Panigrahi B K;Gollapudi S V R S (ETV and ECE Dep, National Institute of Technical Teachers, Training and Research, Chandigarh) : Bacterial foraging optimization technique cascaded with adaptive filter to enhance peak signal to noise ratio from single image. IETE J Res 2009, 55(4), 173-9.

Proposes a new approach to enhance peak signal to noise ratio of highly corrupted image affected by impulse noise. The proposed technique is implemented using an adaptive median filter and the bacterial foraging optimization (BFO) technique. The adaptive median filter is used to identify pixels affected by noise and replace them with median value to keep the information uncorrupted. The BFO technique minimizes errors between adaptive median filter output image and noisy image to maintain an error percentage of 0.0001. It has been observed that results of the proposed method are superior to conventional methods in terms of perceptual image quality as well as clarity and smoothness in edge regions of the resultant image. This technique can remove the salt-and-pepper noise of highly corrupted images with a noise as high as 90%.

4 illus, 4 tables, 10 ref

017461   Azni M;Pyndiah R;Mokrani K;Guilloud F (Electronics Dep, Bejaia Univ, 06000 Bejaia, Algeria) : Joint source and channel coding for real time H.264 coded video transmission using mobile hand-held devices. IETE J Res 2009, 55(4), 154-61.

A joint source channel coding scheme for robust real time transmission of H.264/AVC coded video over noisy channels and under bandwidth limitations. A new method of rate adaptation to the allowed maximum channel transmission rate which does not assume source rate control in the source coder has been proposed. This keeps system complexity reasonable and improves the perceived decoded video quality. These are desirable features for two-way video-conferencing using mobile hand-held devices. Data partitioning is used to code the source data. Then, unequal error protection is applied at the network abstraction layer. For robustness, we use joint optimization of forward error correction at the transmitter and error concealment at the source decoder. A low complexity and efficient algorithm of channel code rate allocation to the network abstraction layer units is then developed. Simulation results show that the perceived decoded video quality is improved for small levels of signal-to-noise ratio.

7 illus, 1 table, 21 ref

017460   Azadh A;Saberi M;Ghorbani S (Industrial Engineering and Center of Excellence for Intelligent Experi, College of Engineering, Tehran Univ, Iran, Email: aazadeh@ut.ac.ir) : ANFIS algorithm for improved forecasting of oil consumption: a case study of USA, Russia, India and Brazil. J scient ind Res 2010, 69(3), 194-203.

This paper proposed an adaptive network-based fuzzy inference system (ANFIS) algorithm for oil consumption forecasting based on monthly oil consumption (January 2001 - September 2006) in USA, Russia, India and Brazil. Using mean absolute percentage error (MAPE), efficiency of different ANFIS models was examined. Proposed algorithm used Autocorrelation Function (ACF) to define input variables irrespective of trial and error method (TEM). Algorithm for calculating ANFIS performance is based on its closed and open simulation abilities.

6 illus, 6 tables, 28 ref

017459   Anbazhagan P;Sitharam T G (Civil Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: anbazhagan@civil.iisc.ernet.in) : Estimation of ground response parameters and comparison with field measurements. Indian Geotech J 2009, 39(3), 245-70.

Design of seismic resistant structures requires an estimation of the site amplification during expected earthquakes and also the response spectrum at the ground surface. This paper summarizes the results of site specific ground response analysis for Bangalore and comparison of predominant frequency of the soil column with experimentally measured predominant frequency by ambient noise survey. The subsurface soil profile was assessed from carefully selected 170 borelogs out of the available 850 bore logs in the study area of 220 km^{2. The response spectrum and amplification have been evaluated for each soil layer at corresponding borehole locations based on one-dimensional ground response analysis. The estimated peak acceleration at ground surface varies from 0.088g to 0.66g. The natural period of the soil column, peak spectral acceleration (PSA) and frequency at peak spectral acceleration at each borehole location have been evaluated and through interpolation they are presented in the form of maps. The period of the soil column varies from 0.01s to 0.45s, PSA varies from 0.2 to 2.5g and frequency at PSA varies from 3.2Hz to 20Hz. The northern and eastern parts of the city are in the low SA zone for all the frequencies. Period of soil column calculated using site response study and the predominant frequency estimated from field experimental studies are comparable.}

19 illus, 3 tables, 24 ref

017458   Anantharamulu N;Radha Velchuri;Sarojini T; Madhavi K;Prasad G;Vithal M (Chemistry Dep, Osmania Univ, Hyderabad-500 007, Email: muga_vithal@osmania.ac.in) : Preparation, characterization and conductivity studies of NaAlSb(PO₄)₃ and HAlSb(PO₄)₃. Indian J Engng Mater Sci 2009, 16(5), 347-54.

NaAlSb(PO₄)₃ and HAlSb(PO₄)₃ are prepared by solid-state and metathesis reactions respectively. They are characterized by powder XRD, IR and solid-state ³¹P-MAS NMR spectroscopy. These two compounds crystallize in the hexagonal NASJCON structure with the space group of R 3 c. Their infrared spectra exhibit characteristic vibrational bands of PO₄ tetrahedra. The ³¹P-MAS NMR spectra of NaAlSb(PO₄)₃ and HAlSb(PO₄)₃ are characterized by a symmetric single peak around 9 ppm suggesting only one type of phosphorous in the hexagonal lattice. The activation energies for conduction and relaxation are more for NaAlSb(PO₄)₃ compared to the values of HAlSb(PO₄)₃. The isothermal conductivity of NaAlSb(PO₄)₃ is higher than the conductivity of HAlSb(PO₄)₃. The imaginary parts of the impedance, (Z") and electric modulus (M") against log frequency show single peaks in both Z" and M"spectra.

7 illus, 7 tables, 33 ref

017457   Anand D;Bedi R;Chandra R;Tiwari S K (Mechanical Engineering Dep, Dr B R Ambedkar National Institute of Technology, Jalandhar, Email: bediraman74@gmail.com) : Hygrothermal ageing on properties of polyester/glass composites. J scient ind Res 2010, 69(3), 204-7.

This study presents hygrothermal degradation of unidirectional glass fiber reinforced polyester composites (GFRPC). Water absorption of GFRPC immersed in distilled water (DW) at RT and river water (RW) at different temperatures was studied. Water absorption of GFRPC immersed in distilled water increased with time and temperature except for samples immersed in river water at 60°C. Moisture absorption (%) in GFRPC increased with increase in fiber content. Degradation of properties [loss tangent (tan δ), glass transition temperature (T_g) and storage modulus (E')] was determined after moisture saturation and drying of specimens using dynamic mechanical analyser (DMA). E' and T_g decreased after moisture absorption for all specimens. T_g showed an almost complete recovery after drying in most cases, whereas E' reduced permanently after hygrothermal conditioning.

2 tables, 8 ref

017456   Alamelumangai V;Natarajan S P (Electronics and Instrumentation Engineering, Annamalai Univ, Annamalainagar, Chidambaram-608 002, Email: almjai@yahoo.com) : Tuning methods of multi-loop controller for a multivariable process. Indian J Sci Technol 2010, 3(2), 131-8.

All chemical processes in process industries usually have two or more controlled outputs requiring two or more manipulated variables generally called Multi Output (MIMO) process. In this paper an attempt is made to review the practical difficulty in applying control strategies for a multivariable process. The control strategies considered here are multi-loop PID control, multi-loop IMC-PID control and multi loop H_∞-PID control. These strategies are reviewed by applying them to the quadruple tank process which is the bench mark multivariable process.

18 illus, 4 tables, 10 ref

017455   Akkurt A (Faculty of Industrial Arts Education, Gazi Univ, Golbasi, Ankara, Turkey, Email: aakkurt@gazi.edu.tr ) : Surface properties of the cut face obtained by different cutting methods from AISI 304 stainless steel materials. Indian J Engng Mater Sci 2009, 16(6), 373-84.

AISI 304 stainless steel which is widely used almost in all industrial applications is accounted for approximately 50% of the world's stainless steel production and consumption. Because of its aesthetic view in architectures, resistance against corrosion and chemicals, it became as the most preferred material. Today several methods for machining of AISI 304 stainless steel are available. Most of these methods result in loss of superior properties of the stainless steel material and makes it to act like other ordinary materials within the machined zones. In this study, specimens taken from the AISI 304 material are cut by the cutting methods which are commonly used in machining. The resulting surface properties of these specimens are compared with original materials with respect to different methods. Finally mechanical and metallurgical properties of the cut face obtained by each method are examined. The results show that cutting with abrasive water jet gives the most favorable result while oxygen cutting gives the worst.

11 illus, 4 tables, 21 ref

017454   Aggarwal G;Kachhwaha S S;Mishra R S (Science & Technology Dep, , New Mehrauli Road, New Delhi-110 016, Email: sskachhwaha@rediffmail.com) : Parametric study of induced draft counter flow rectangular cooling tower based on exergy analysis. J scient ind Res 2010, 69(4), 284-92.

Study presents development of a simple and efficient mathematical model, in which energy, draft and pressure equations are solved simultaneously. Model was validated with experimental data collected from an induced draft counter flow rectangular cooling tower of a refrigeration plant (capacity, 220 tonnes) in a dairy industry at Ambala (India). Model predictions and experimental data match satisfactorily. In a parametric study, wet bulb temperature of inlet air plays a significant role on air and water outlet temperatures, evaporation loss, fan power, thermal efficiency, exergy destruction and second law efficiency.

3 illus, 2 tables, 18 ref

017453   Aggarwal A;Singh H;Kumar P;Singh M (Mechanical and Automation Engineering Dep, Maharaja Agrasen Institute of Technology, Rohini, Delhi-110 085, Email: aman_aggarwal28@yahoo.co.uk) : Optimizing feed and radial forces in CNC machining of P-20 tool steel through Taguchi's parameter design approach. Indian J Engng Mater Sci 2009, 16(1), 23-32.

The objective of the paper is to obtain an optimal setting of CNC machining process parameters (cutting speed, feed rate, depth of cut, nose radius and cutting environment) resulting in optimal values of the feed and radial forces while machining P-20 tool steel with TiN coated tungsten carbide inserts. The effects of the selected process parameters on the chosen characteristics and the subsequent optimal settings of the parameters have been accomplished using Taguchi's parameter design approach. The analysis of the results shows that the optimal settings for low values of feed and radial forces arc high cutting speed, low feed rate and depth of cut, small nose radius and cryogenic cutting environment.

10 illus, 6 tables, 17 ref

016485   Yun J G;Lee J D;Park B G (NO, Inter-University Semiconductor Research Center and School of Electric, San 56-1, Sillim-dong, Gwanak-ku, Seoul 151-742, Republic of Korea) : Various flash memory devices of novel design. IETE Tech Rev 2009, 26(4), 247-57.

Various novel flash memory devices for both NOR and NAND types are reviewed. In NOR-type flash memory devices, 2-bit/cell devices and their technology trends are addressed. Furthermore, multi-site charge-trapping schemes with more-than-2-bit/cell operation are also studied in the fin SONOS (silicon oxide-nitride oxide semiconductor) flash memory having independent double gates and the stacked vertical-channel NOR flash memory. In the NAND-type flash memory, devices having extended word-lines are investigated. As well as the short-channel effect, fluctuation and process limitation issues are considered for the highly scaled devices. Some future perspectives, including a stacked array, are discussed for high-density NAND flash memories.

14 illus, 17 ref

016484   Yeole S N;Harode S M;Nadre R G (Family Resource Management Dep, College of Home Science, Marathwada Agricultural University, Parbhani Maharashtra) : Designing and testing of low cost cooling dervices for storage of vegetables in summar. Asian J Home Sci 2009, 3(2), 126-9.

Based on the principle of evaporative cooling five low cost cooling devices were designed using low cost and easily available materials which could be utilized by the rural masses and economically backward class. Five different models of 40 cm x 40 cm x 60 cm size and the storage capacity of 96 liters were made. The vegetables selected for storage in the devices were lady's finger, cluster beans, spinach, each 350 gms and coriander leaves 50 gms. The experiment was carried out for subsequent seven day during summer season. The other observation regarding temperature, relative humidity and physiological characteristics of the stored vegetables were assessed by the selected panel members using score card by applying 5 point scale. Average temperature drop inside the devices was to the extent of 10°C to 12°C than that of room temperature. The lowest minimum temperature was noted in B model. Maximum relative humidity was high in all models, higher being in B model. Ranging from 81 % to 91 %. Average physiological weight losses were observed minimum in B model in all vegetables on third day the losses were 1.42 to 10 per cent in spinach. Moisture losses were observed in model A.E. and minimum in model B in all selected vegetables. Average vitamin 'C' losses were maximum in model E followed by A comparatively per cent losses were minimum in B, C, D, model. Physical characteristics maximum score of color, texture, aroma and overall freshness in model B. Based on the ranking of mean score B model (Exterior materials gunny bag with coal) secured first rank for all the characteristics. Indicating best performance in the storage of selected vegetables in peak summer. Statistical analysis proved highly significant different in all the models.

2 tables, 6 ref

016483   Vivekanandan N (Central Water and Power Research Station, , P.O. Khadakwasla Reseaerch Station, Pune-411 024) : Comparative study of flood estimates using six statistical distributions. Indian J Pwr River Valley Dev 2008, 58(7-8), 138-44.

Gives details of a study involving the use of six statistical chstributions for estimation of flood for different return periods for the rivers Godavari at Perur, Narmada at Mortakka, Tapi at Hope Bridge and Vamsadhara at Srikakulam sites. Goodness of fit tests like Anderson-Darling, Chi-square and Kolmogorov-Smirnov were used for checking the adequacy of fitting of distributions to the recorded data. Diagnostic analysis involving D-index was used for evaluating the suitability of the probability distribution for the data under study. The paper presents the Log Pearson Type III to be the best suited, among six statistical distributions studied, for modelling of flood data for Godavari, Narmada and Vamsadhara rivers while Pearson Type III for river Tapi. The probability plots of observed and estimated flood/discharge using six statistical distributions for different return periods are developed and presented.

4 illus, 10 tables, 10 ref

016482   Verma C;Abegaonkar M P;Basu A;Koul S K (Centre for Applied Research in Electronics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016) : Effect of lossy dielectric overlays on the read-range of UHF RFID tags. IETE J Res 2009, 55(2), 68-72.

Effect of a lossy overlay on the read-range of UHF RFID tags is studied. The design of the tag antenna is optimized for long read-ranges and then the effects of a lossy overlay (cover) on its properties are studied. The tags are simulated with and without the lossy overlay material. The input impedance of tag antenna, power transmission coefficient and read-range are calculated and compared for the two cases of with and without overlay. Further, optimization of tag with lossy dielectric overlay is carried out. It is observed that even with the overlay of a lossy dielectric, read-range up to 9 m can be obtained by properly matching the antenna with the RFID IC.

4 illus, 5 tables, 6 ref

016481   Venketesh P;Venkatesan R (Computer Science and Engineering Dep, PSG College of Technology, Peelamedu, Coimbatore-641 004) : Survey on applications of neural networks and evolutionary techniques in web caching. IETE Tech Rev 2009, 26(3), 171-80.

Web caching has been used extensively to enhance content delivery to the clients by minimizing client-observed latency, reducing network bandwidth usage and improving scalability of the network. Caching performance can be improved by designing good replacement policies, prefetching techniques, clustering of web users and proper placement of proxy caches in the network. Discusses the various approaches that were designed based on neural networks, genetic algorithms and fuzzy logic to optimize the performance of web caching. The approaches discussed here proved to be more effective in solving the problems as compared to the conventional techniques that were used earlier in this problem domain. Neural networks and evolutionary algorithms can be considered for further exploration in the various issues related to web caching and content delivery.

4 illus, 27 ref

016480   Vankayala Kiran;Srinivasan S (Inorganic and Physical Chemistry Dep, Indian Institute of Science, Bangalore-560 012) : Short review on direct borohydride fuel cells. J Indian Inst Sci 2009, 89(4), 447-54.

Direct borohydride fuel cells (DBFC) use aqueous alkaline sodium borohydride (NaBH₄) as anode fuel to generate electric power with either oxygen or hydrogen peroxide as oxidant. The DBFCs are projected to be very handy for portable power appliances such as laptops and mobile phones in addition to their use in extreme conditions such as underwater and portable military applications. Discusses the progress in DBFC research based on electrode materials and membranes.

^iia4 illus, 2 tables, 53 ref

016479   Tanbeer S K;Ahmed C F;Jeong B S (Computer Engineering Dep, Kyung Hee University, 1 Seochun-dong, Kihung-gu, Youngin-si, Gyonggi-do, 446-701, Republic of Korea) : Efficient single-pass algorithm for mining association rules from wireless sensor network. IETE Tech Rev 2009, 26(4), 280-9.

With advances in technology, use of wireless sensor networks (WSNs) has widely increased in recent decades. In general, WSNs produce a large amount of data in the form of streams. Recently, data-mining techniques have received a great deal of attention for their utility in extracting knowledge from WSN data. Mining association rules on the sensor data provides useful information for different applications. Even though there have been some efforts to address this issue in WSNs, they are not suitable when the user might not have enough opportunity to scan the database multiple times, which is highly common in the WSN environment. Proposes a new tree-based data structure called sensor pattern tree (SP-tree) to generate the set of all association rules from WSN data with one scan over the sensor database. The SP-tree is constructed in frequency-descending order, which facilitates an efficient mining using the frequent pattern (FP)-growth-based mining technique. The experimental results show that SP-tree outperforms related algorithms in finding association rules from WSN data.

6 illus, 1 table, 17 ref

016478   Sudha S;Suresh G R;Sukanesh R (NO, Sona College of Technology, Salem-5) : Speckle noise reduction in ultrasound images using context-based adaptive wavelet thresholding. IETE J Res 2009, 55(3), 135-43.

In medical imaging, image denoising has become a very essential exercise all through the diagnosis. Compromise between the preservation of useful diagnostic information and noise suppression must be respected in medical images. One of the ultimate goals of an imaging modality is to provide the clinician with the best possible information needed to make an accurate diagnosis. Ultrasound images suffer from an intrinsic artifact called speckle. Speckle degrades spatial and contrast resolution and obscures the underlying anatomy. Thus, it seems sensible to reduce speckle artifacts before performing image analysis, provided the image that might distinguish one tissue from another is preserved. The main goal of this thesis was the development of novel methods for suppression of speckle in medical ultrasound images in the wavelet domain. Authors have adopted weighted variance for estimating the threshold and multiscale product scheme for thresholding the coefficients. To employ the wavelet interscale dependencies, the adjacent wavelet subbands are multiplied. Multiplying the adjacent wavelet scales would sharpen the important structures while reducing noise. In the multiscale products, edges can be efficiently discriminated from noise. Then, an adaptive threshold was calculated and imposed on the products, instead of on the wavelet coefficients, to identify important features. Fundamentally speckle noise is a signal-dependent one, and so weighted variance of each background pixel was taken into account while calculating threshold. Experiments show that the proposed scheme better suppresses noise and preserves edges than other wavelet-denoising methods. Experiments with synthetic and real ultrasound imagery show that the proposed method improves the signal-to-noise ratio and preserves edge clarity.

8 illus, 2 tables, 20 ref

016477   Sinha N N;Munichandraiah N (Inorganic and Physical Chemistry Dep, Indian Institute of Science, Bangalore-560 012) : Effect of particle size on performance of cathode materials of Li-ion batteries. J Indian Inst Sci 2009, 89(4), 381-92.

Beginning with the `frog-leg experiment' by Galvani (1786), followed by the demonstrations of Volta pile by Volta (1792) and lead-acid accumulator by Plante' (1859), several battery chemistries have been developed and realized commercially. The development of lithium-ion rechargeable battery in the early 1990s is a breakthrough in the science and technology of batteries. Owing to its high energy density and high operating voltage, the Li-ion battery has become the battery of choice for various portable applications such as note-book computers, cellular telephones, camcorders, etc. Huge efforts are underway in succeeding the development of large size batteries for electric vehicle applications. The origin of lithium-ion battery lies in the discovery that Li^{+-ions can reversibly be intercalated into/de-intercalated from the Van der Walls gap between graphene sheets of carbon materials at a potential close to the Li/Li+ electrode. By employing carbon as the negative electrode material in rechargeable lithium-ion batteries, the problems associated with metallic lithium in rechargeable lithium batteries have been mitigated. Complimentary investigations on intercalation compounds based on transition metals have resulted in establishing LiCoO₂ as the promising cathode material. By employing carbon and LiCoO₂, respectively, as the negative and positive electrodes in a non-aqueous lithium-salt electrolyte, a Li-ion cell with a voltage value of about 3.5 V has resulted. Subsequent to commercialization of Li-ion batteries, a number of research activities concerning various aspects of the battery components began in several laboratories across the globe. Regarding the positive electrode materials, research priorities have been to develop different kinds of active materials concerning various aspects such as safety, high capacity, low cost, high stability with long cycle-life, environmental compatibility, understanding relationships between crystallographic and electrochemical properties. Discusses the published literature on different positive electrode materials of Li-ion batteries, with a focus on the effect of particle size on electrochemical performance.}

4 illus, 188 ref

016476   Shivareddy M S;Vishwanadh G K (Civil Engg Dep, TRR College of Engg., Patancheru, Hyderabad-502 319, Email: ms_shivareddy39@yahoo.co.in) : Hydraulic exponents for an egg-shaped tunnel section. Indian J Pwr River Valley Dev 2008, 58(7-8), 131-7.

Studies method of evaluation of the hydraulic exponents which vary with depth is proposed for a standard egg-shaped tunnel section. The results of the profile computations based on the step-by-step method are compared with the corresponding results of the direct integration method which uses the hydraulic exponents. The results find direct application in hydraulic engineering practice, where flow profile lengths are needed for design purposes

6 illus, 1 table, 14 ref

016475   Sheela T;Raja J (NO, Sathyabama University, Chennai, Email: sheela_saiit@yahoo.com) : Maximization of throughput by effective queue management scheme for high speed network. Indian J Sci Technol 2009, 2(3), 28-31.

New algorithm is proposed to control the congestion in the network based on the minimum drop ratio. Explicit Control Protocol (XCP) is adopted for high speed network, where the queue threshold is assigned to be 85% of the queue size. At the time of congestion, whenever the queue size reaches the threshold value, a new buffer is initialized which is half the queue size. This mechanism thus prevents the drop of packets and hence the drop ratio is minimized and throughput is maximized. Performance of bandwidth utilization, throughput and drop ratio is presented.

8 illus, 17 ref

016474   Sharma P;Koul S K (Centre for Applied Research in Electronics (CARE), Indian Institute of Technology, Hauz Khas, New Delhi-110 016) : Design and development of millimeter-wave micromachined patch antennas. IETE J Res 2009, 55(1), 40-9.

Reports design, development and fabrication of high-performance Ka-band micromachined patch antennas using monolithic microwave integrated circuit (MMIC)-compatible process technology. The main emphasis of this is to use radio frequency (RF) sputtering as the potential metal-dielectric film deposition process for rapid prototyping of many antenna structures in the absence of access to a well-established MEMS foundry. The fabricated antennas exhibited 4%-5% of impedance bandwidth, which is much wider than the one fabricated on bulk high-index substrates.

18 illus, 12 ref

016473   Shaikh M Z;Kodad S F;Jinaga B C (EEE Dep, Aurora's Engineering College, Bhongir, Hyderabad, Email: mzshaikh2003@yahoo.co.in) : Optimized high-sensitivity capacitive MEMS for blood pressure treatment. Indian J Sci Technol 2008, 1(4), 1-4.

High-sensitivity capacitive pressure transducer with active processing circuit on the chip has been demonstrated and evaluated. The transducer configuration has been optimized by computer-aided simulation and design to achieve highest sensitivity for a given maximum dimension. The measured sensitivity of the devices is in the range of 50-150 MV/V mmHg, which is approximately one order of magnitude higher than the sensitivity of the piezoresistive pressure transducer of comparable size. Theoretical analysis also shows that sensitivity of the order of 1000 pV/V mmHg is also possible using the capacitive approach if the dimension of the device can be enlarged and the full-scale pressure range is lowered.

5 illus, 9 ref

016472   Sarvaiya J N;Pandey P C;Pandey V K (Electronics Engineering Dep, SVNIT, Surat-395 007) : Impedance detector for glottography. IETE J Res 2009, 55(3), 100-5.

Impedance glottography, or electroglottography, is a noninvasive technique for monitoring the variation of the degree of contact between the vibrating vocal cords during voice production. Electrical impedance is sensed using a pair of electrodes placed on either side of the larynx, by injecting a low-level high-frequency current. A wide-band impedance detector circuit has been developed using a precision rectifier based on voltage feedback clamping amplifier and approximately linear-phase lowpass filter. The circuit can be used for obtaining electroglottogram signal for diagnosis of vocal fold disorders.

7 illus, 17 ref

016471   Sappal A S;Patterh M S;Sharma S (NO, University College of Engineering, Punjabi University, Patiala, Punjab, Email: sappal73as@pbi.ac.in) : Mathematical modeling of power amplifier with memory effects. Indian J Sci Technol 2009, 2(3), 22-3.

Simulation has become a key issue in analyzing, optimizing and designing wireless systems. A mathematical model for the power amplifier is implemented in Simulink to extend the RF Blockset to model wideband applications such as WCDMA. This model for the power amplifier implements a modified Saleh model. Saleh model is a quasi memory-less nonlinear model, and is converted into a straightforward and easy to implement model with memory effects.

9 illus, 4 tables

016470   Saikrishna C N;Ramaiah K V;Allam Prabhu S; Bhaumik S K (Materials Science Div, National Aeropsace Laboratories, Council of Scientific and Industrial, Bangalore-560 017, Email: subir@ccs.nal.res.in) : On stability of NiTi wire during thermo-mechanical cycling. Bull Mater Sci 2009, 32(3), 343-52.

Use of NiTi wire as thermal actuator involves repeated thermal cycling through the transformation range under a constant or fluctuating load. The stability of the material under such conditions has been a concern for the past many years. Experimental results show that for a given alloy composition, the repetitive functional behaviour of NiTi wire is largely dependent on the processing schedule/parameters and the stress-strain regime of thermo-mechanical cycling (TMC). Among the various processing parameters, retained cold work in the material and the shape memory annealing temperature/time have significant influence. It has been shown in the study that for a stable functional behaviour, the material needs to be tailored through judicious selection of these parameters. Study also shows that, after processing, the material requires an additional stabilization treatment for ensuring minimal variation in the repetitive functional response upon TMC.

14 illus, 2 tables, 20 ref

016469   Sahu A K;Sridhar P;Pitchumani S (NO, Central Electrochemical Research Institute (CECRI), Madras Unit, CSIR Complex, Chennai-600 013) : Mesoporous carbon for polymer electrolyte fuel cell electrodes. J Indian Inst Sci 2009, 89(4), 437-45.

Features the importance of mesoporous carbon as a constituent in the gas diffusion layer for easy reactant permeation and water removal in polymer electrolyte fuel cells. The utility of mesoporous carbon as catalyst support to enhance Pt utilization is also crucial in order to reduce Pt usage to meet both cost and Pt availability constraints. Attempts to provide an overview of the strategy and benefit of using mesoporous carbon to meet the specific requirements of emerging technological applications, such as fuel cells.

^iia2 illus, 135 ref

016468   Roy T;Banerjee D;Kar S (NO, Institute of Radio Physics and Electronics, University of Calcutta, 92, A.P.C. Road, Calcutta-700 009) : Multiple-inclusion magnetic structures useful for millimeter-wave left-handed metamaterial applications. IETE J Res 2009, 55(2), 83-9.

Analytical model equations have been derived from the fundamental principles for effective relative permeability of circular multiple-inclusion magnetic structures like multiple split-ring resonators, spiral resonators and labyrinth resonators, useful for LHM applications. Tailoring of their resonant frequency, their bandwidth and their effective negative permeability is investigated. Thereafter, a suitable structure for operation at millimeter-wave frequency has been explored. When such microstructures are used in a periodic array, the dependence of resonant frequency and bandwidth on the lattice parameter has further been studied.

8 illus, 1 table, 7 ref

016467   Roy A;Mondal J;Mittal K C (Accelerator and Pulse Power Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: aroy@barc.gov.in) : RF properties of 700 MHz, Beta = 0.42 elliptical cavity for high current proton acceleration. Pramana J Phys 2008, 71(6), 1279-89.

BARC is developing a technology for the accelerator-driven sub critical system (ADSS) that will be mainly utilized for the transmutation of nuclear waste and enrichment of U^{233. Design and development of super conducting medium velocity cavity has been taken up as a part of the accelerator-driven sub critical system project. We have studied RF properties of 700 MHz, 13 0.42 single cell elliptical cavity for possible use in high current proton acceleration. The cavity shape optimization studies have been done using SUPERFISH code. A calculation has been done to find out the velocity range over which this cavity can accelerate protons efficiently and to select the number of cellscavity. The cavitys peak electric and magnetic fields, power dissipation P_c, quality factor Q and effective shunt impedance ZT2 were calculated for various cavity dimensions using these codes. Based on these analyses a list of design parameters for the inner cell of the cavity has been suggested for possible use in high current proton accelerator.}

1 illus, 1 table, 16 ref

016466   Rout K;Mohapatra M;Anand S (NO, Institute of Minerals and Materials Technology, Bhubaneswar-751 013) : Lead, cadmium and zinc adsorption on low grade bauxite ore. Indian J envir Prot 2009, 29(1), 30-5.

Low grade bauxite ore is not exploited for alumina production. To investigate a possibility to utilize such ore for remediation of heavy metal ions from aqueous solutions, the present study was taken up. A typical sample containing 26.1 % AI and 18.9 % Fe was used. The major crystalline phases were gibbsite, alumina and goethite. Experimental parameters, such as time, metal ion concentration, amount of adsorbent and pH were varied to generate adsorption data for Pb(lI), Cd(II) and Zn(II) on low grade bauxite. The adsorption equilibrium reached within one hour. Pb(II) adsorption increased with the increase in pH from 2 to 4.5 and remained unaffected with further increase in pH values to 5.25. In case of Cd(II) and Zn(ll) adsorption, the increase was only upto a pH of 3. The adsorption kinetics was found to follow pseudo-second-order model for all the three metal ions. The amounts of Pb(lI), Cd(ll) and Zn(II) adsorbed were 64.35,38.77 and 65.86 mg/g, respectively by keeping the initial metal ion concentration of 300 mg/L. Freundlich isotherm model fitted well to the experimental equilibrium data.

9 illus, 3 tables, 11 ref

016465   Renganathan S;Karthik V;Velan M;Dharmendira Kumar M;Raajenthiren M (Chemical Engineering Dep, Anna University, Alagappa College of Technology, Chennai-600 025) : Antimicrobial activity of Cicca acida against various environmental pathogenic bacterial and fungal species. Indian J envir Prot 2009, 29(1), 44-8.

The main objective of this study is to reveal the antimicrobial activity of Cicca acida against various bacterial and fungal species. Antimicrobial assay was carried out by disiffusion technique. The plant extract of Cicca acida was tested against various bacterial, such as Bacillus subtilis and pseudomonas aeruginosa and fungal species, such as Aspergillus niger, Rhizopus oryzae and Saccharomyces cerevisiae. The plant extracts of Cicca acida showed inhibitory activity against both bacterial and fungal strains. The maximum zone of inhibition for fungal species of Aspergillus niger was observed as 10.0±2.0 mm in ethanol extract. The inhibition effect of antimicrobial agent in Cicca acida was found to be more on the Aspergillus niger when compared to all other microbes studied.

1 table, 26 ref

016464   Ravikumar M K;Niranjana E;Sundar Rajan A; Banerjee A;Gaffoor S A;Shukla A K (Solid State Structural Chemistry Unit, Indian Institute of Science, Bangalore-560 012) : Electrical-energy storage in hybrid ultracapacitors. J Indian Inst Sci 2009, 89(4), 455-63.

There are several ways of storing electrical energy in chemical and physical forms and retrieving it on demand, and ultracapacitors are one among them. Presents the taxonomy of ultracapacitor and describes various types of rechargeable-battery electrodes that can be used to realize the hybrid ultracapacitors in conjunction with a high-surface-area-graphitic-carbon electrode. While the electrical energy is stored in a battery electrode in chemical form, it is stored in physical form as charge in the electrical double-layer formed between the electrolyte and the high-surface-area-carbon electrodes. Discusses various types of hybrid ultracapacitors along with the possible applications.

^iia4 illus, 1 table, 41 ref

016463   Raju B V S S N;Deergha Rao K (NO, Research and Training Unit for Navigational Electronics, Osmania Univ, Hyderabad-500 007) : Robust multiuser detection in synchronous chaotic modulation systems. IETE J Res 2009, 55(2), 54-62.

In reality, many wireless channels exhibit marked departure from Gaussian noise assumption, causing significant performance loss when linear multiuser detectors, which are optimum in the case of Gaussian noise, are used for detection of code division multiple access signals. Proposes a new influence function-based M-estimator and its application to the problem of robust multiuser detection of code division multiple access signals in chaotic modulation systems, in which user data are modulated by an analog chaotic series rather than periodic binary spreading sequences, against non-Gaussian background noise. The solution to this robust detection problem is not in closed form and requires an iterative procedure, which is a limitation in its practical use. However, it causes a little attendant increase in computational complexity in practical applications. Robustness analysis and simulation results show that the proposed detector offers significant performance gains over least-squares and Huber M -estimator-based detectors in chaotic modulation systems in non-Gaussian noise.

10 illus, 1 table, 14 ref

016462   Rajaji L;Kumar C (NO, Sathyabama University, Chennai-600 119, Email: rajajiloganathan@yahoo.co.in) : Neural network controller based induction generator for wind turbine applications. Indian J Sci Technol 2009, 2(2), 70-4.

Presents the analysis and simulation of stand-alone wind driven doubly fed induction generator using nueral network controller. With constant frequency, the machine is capable of generating constant voltage irrespective of speed and load variations. The variable speed wind turbines plays important role in wind energy market globally. Specially, the pitch regulated wind turbines with doubly fed induction generator (DFIG) systems are more popular and well proven technology across the world.

16 illus, 8 ref

016461   Quddusa Sultana;Sunehra D;Sarma A D; Somasekhar Rao P V D (R & T Unit for Navigational Electronics, Osmania University, Hyderabad-500 007) : Comparative analysis of the techniques for estimation of GPS DOP over Indian region. IETE J Res 2009, 55(1), 28-34.

Estimation of Dilution of Precision (DOP) plays an important role in aviation, terrestrial and marine navigation applications. Results due to four techniques to estimate DOP namely, Kihara's method, `all-in-view' SVs, `best-5' SVs and `best-4' SVs are investigated. Experiments are performed using Novatel (DL-4plus) GPS receiver and the collected data is used for the analysis. Bancroft algorithm is used to find preliminary position of the receiver. Using this position of the receiver and satellite coordinates, DOP is estimated. Comparative analysis of the specified techniques is performed. For most of the time, DOP values due to `all-in-view' SVs are found as the best.

8 illus, 2 tables

016460   Prem Kumar T;Sri Devi Kumari T;Manuel Stephan A (Electrochemical Power Systems Div, Central Electrochemical Research Institute, Council of Scientific and, Karaikudi-630 006) : Carbonaceous anode materials for lithium-ion batteries. J Indian Inst Sci 2009, 89(4), 393-424.

Graphites and hard carbons are the mainstay of anode materials in practical lithium-ion batteries. With their dominance beginning to be threatened by other alternative anode materials such as silicon and intermetallics, continual research is directed at exploring known carbonaceous materials as well as at synthesizing new carbon-based anodes. After a review of lithium storage mechanisms in various carbon forms, the study explores avenues for crossovers between chemistry and materials science for tailoring carbonaceous materials that can cater to increasing power demands of emerging technologies. Suggests opportunities and problem areas in anodes based on carbon composites as well as novel carbonaceous materials such as kish graphites, carbon nanotubes, nanofibers, curved carbon lattices and graphenes that are expected to prolong the legacy of carbon in lithium-ion batteries.

^iia23 illus, 356 ref

016459   Popescu C;Angeles M D L;Soto C;Martinez Lastra J L (NO, Institute of Production Engineering, Tampere University of Technology, Korkeakoulunkatu 6, 33101 Tampere) : Runtime modeling of flow for dynamic deadlock-free scheduling in service-oriented factory automation systems. IETE Tech Rev 2009, 26(3), 203-12.

Changes in equipment and production demand cannot be predicted at the design stage. Therefore, decision taking mechanisms must rely on real time information collected from the shop floor. To perform scheduling and routing optimization, not only modifications in values of parameters of interest, but also in the flow itself must be accounted for. Addresses this problem and proposes a method to formally model, at runtime, the flow within a service-oriented manufacturing line. The resulting representation assists deadlock-free dynamic scheduling of the system.

5 illus, 34 ref

016458   Pawan Kumar;Kolhe K P;Kolhe P R;Datta C K (Mechanical Engineering Dep, Delhi College of Engineering, Delhi) : Optimizing pulsed GTAW process parameters for bead geometry of titanium alloy using taguchi method. Asian Sci 2009, 4(1-2), 78-82.

Selection of process parameters for obtaining optimal weld bead geometry of Ti-6Al-AV titanium alloy in the pulsed gas tungsten arc welding (GTAW) is presented. The bead geometry includes bead penetration, bead width and bead height. All these characteristics were considered together in the selection of process parameters using various Ar + He (Argon + Helium) mixtures as a shielding gas with sinusoidal AC wave and modified Taguchi method was used to analyse the effect of each welding process parameter on bead geometry properties. Experimental results were furnished to illustrate this approach.

2 illus, 8 tables, 7 ref

016457   Pasricha S;Sharma S (ECE Dep, Amity School of Engineering and Technology, Bijwasan, New Delhi-110 061, Email: shiavani.pasricha@gmail.com) : FPGA based design of Reed Solomon codes. Indian J Sci Technol 2009, 2(4), 48-52.

Presents a novel architecture design for forward error correction technique based on RS coding scheme for wireless applications. The design was created using System Generator for DSP tool from Xilinx and was simulated on Matlab/Simulink environment. The hardware description language source code for different blocks was generated and the design was subjected to severe functional and timing constraints using Xilinx Foundation series and ModelSim tools. Synplify Pro tool was finally used to synthesize the complete design. The overall architecture for RS Coder-Decoder was implemented on Xilinx Virtex-II XC2v250 device and consumed slices 1429 for the CODEC at a clock frequency of 90 MHz. The architecture design power consumption analysis was done using the Xilinx Xpower tool and it came out to be about 783 mW.

4 illus, 1 table, 12 ref

016456   Pasricha R;Sharma S (NO, CEC, Landran (Mohali)-140 307) : Linearization of volterra series mdoel power amplifier for wideband WCDMA base stations. Indian J Sci Technol 2009, 2(3), 32-3.

Digital pre-distortion techniques are widely used in linearization of RF power amplifiers. Lookup-table (LUT) type Adaptive Digital pre-Distortion (ADPD) is presented. In this algorithm, an output signal of the Power Amplifier (PA) is used as reference signal. It is used to update the coefficients of the LUT, so that characteristics of the PA, such as temperature dependence, do not have influence on the convergence performances. Simulation results have been presented.

5 illus, 6 ref

016455   Pandian G;Rama Reddy S (Electrical and Electronics Engineering Dep, Sathyabama University, Chennai, Email: pandian1960@yahoo.co.in) : Simulaion and analysis of multilevel inverter fed induction motor drive. Indian J Sci Technol 2009, 2(2), 67-9.

Presents the simulation of three phase nine level inverter fed induction motor drive. The poor quality of voltage and current of a conventional inverter fed induction machine is due to the presence of harmonics and hence there is significant level of energy losses. The nine level inverter is used to reduce the harmonics. The inverters with a large number of steps can generate high quality voltage waveforms. The nine levels can follow a voltage reference with accuracy and with the advantage that the generated voltage can be modulated in amplitude instead of pulse-width modulation. An active harmonic elimination method is applied to eliminate any number of specific higher order harmonics of multilevel converters with unequal dc voltages. The simulation of three phase nine level inverter fed induction motor model is done using Simulink.

7 illus, 12 ref

016454   Palanivelraja S;Chockalingam M P (Civil Engineering Dep, Annamalai University, Annamalainagar-608 002) : Multiple point source complex model-average concentrations for the user specified sampling period. Indian J envir Prot 2009, 29(1), 62-8.

A self-designed computer aieded Gaussian dispersion model, namely multiple point source complex model- Average concentrations for the user specified sampling period (MPC-AUSP) has been evolved and it is used for predicting the GLCs of short-term S02 concentrations in the ambient environment of NLC complex.

4 illus, 3 tables, 19 ref

016453   Onkar A B (Chandrapur Super Thermal Power Station, , Chandrapur-442 404) : Energy-environment implication by reducing specific engery consumption in thermal power plant. Indian J envir Prot 2009, 29(1), 53-61.

Energy audit is an essential part for developing energy saving devices. Presently energy is limited and substitutes are not sufficient. In the present study computerized model developed for the quick and efficient energy auditing with the help of C- language programme. it also suggest some alternate devices suitable for the case. It presents a mathematical model, which provides a simple but useful method of assessing the efficiency of motors under actual working conditions, and also outlines a procedure for estimating power saving by replacement of under loaded motors with smaller Kw motors.

15 illus

016452   Nayak S;Nandagiri L (Civil Engineering Dep, Anjuman Engineering College, Bhatkal-581 320, Email: ) : Characterization of small-scale groundwater irrigation schemes in a humid coastal region of southern India. J trop Agric 2009, 47(1-2), 37-42.

Small-scale groundwater irrigation schemes involving large diameter wells are prevalent in the coastal district of Uttar a Kannada, Kamataka State, India. A study was conducted to assess the characteristics of these large diameter open wells and the hydraulic properties of shallow aquifers. Field tests were conducted in 19 wells to assess their potential to supply irrigation water requirements of the region. Constant discharge pump tests indicated significant spatial variations in aquifer transmissivity (5.60 to 64.55 m^{2-day-1) and specific yield (0.063 to 0.95). Low transmissivity values signify poor potential of the aquifer to supply irrigation water needs. Exponential prediction models linking transmissivity and well specific capacity gave a good fit. Implications of spatial variability in aquifer parameters on irrigation development in the region are highlighted.}

5 illus, 2 tables, 15 ref

016451   Narayanan R M;Chuang J;Mohan K M (Electrical Engineering Dep, The Pennsylvania State University, University Park, PA 16802, USA) : Propagation effects on noise-modulated randomly polarized ultrawideband communication system. IETE Tech Rev 2009, 26(4), 303-8.

Noise-modulated ultrawideband covert communication system has been developed in order to conceal data sent over wireless channels. The modulated signal containing the coherent carrier is mixed with a sample of an ultrawideband (UWB) random noise signal. The frequency range of the UWB noise signal is chosen such that the lower sideband of the mixing process falls over its own frequency range. The frequency-converted noise-like signal and the noise key are simultaneously transmitted over orthogonal horizontal (H) and vertical (V) polarizations. At the receiver, both orthogonally polarized signals are amplified, mixed together in an upper sideband up-converter and demodulated. The H and the V polarized signals are affected differently due to the differential attenuation and phase shift in the propagation channel. Results of simulations to assess the impact of various propagation factors, such as frequency-selective fading and absorption, multipath, and differential attenuation on polarization channels on bit error rate (BER) performance, are presented. The primary cause of degradation in error performance is high multipath reflection.

8 illus, 10 ref