027146   SCHMIDT F C, SILVA A C C, ZANOELO E, LAURINDO J B (Chemical Engineering Dep, Federal Univ of Parana, PR 81531-980, Brazil, Email: franciny@ufpr.br) : Kinetics of vacuum and air cooling of chicken breasts arranged in stacks. J Food Sci Technol 2018, 55(6), 2288-97.

The aim of this study was to compare the vacuum and air cooling of cooked chicken breast samples arranged in stacks with one, two and three layers (1 kg per layer). The cooling rate obtained with vacuum cooling was approximately three times faster than that of air cooling. Moreover, a more homogeneous cooling was obtained with vacuum cooling, with similar temperature reductions for samples at different positions of the stack. On the other hand, vacuum cooling led to mass losses of 11–12 %, while air cooling led to losses of 7–8 %. The counts of mesophiles and psychrophiles of the vacuum-cooled samples were lower than those observed for air-cooled samples after ten days of product storage. Thus, the results presented in this work illustrate the potential benefits and disadvantages of the vacuum cooling technique as compared to the air cooling, especially for the processing of small meat cuts.

4 illus, 2 tables, 37 ref

027145   KALPANADEVI C, SINGH V, SUBRAMANIAN R (Food Engineering Dep, CSIR-Central Food Technological Research Institute, Karnataka - 570 020, Email: subbu@cftri.res.in) : Influence of milling on the nutritional composition of bran from different rice varieties. J Food Sci Technol 2018, 55(6), 2259-69.

The nutritional composition of bran from four rice varieties namely, Jyothi/IR64, Basmati and Agonibora representing high amylose, intermediate amylose and waxy, respectively were evaluated with friction and abrasive mills at different degrees of milling (DOM). Fat and protein content of the bran inversely correlated to amylose content of rice variety. The fat and fibre contents reduced with increased DOM due to increasing starch influx from the endosperm. Abrasive milling produced bran with higher protein content and total dietary fibre, resulting in superior quality bran, while friction milling led to higher fat. Agonibora bran was found to be superior in terms of nutritional quality. Industrial milling resulted in higher protein content in bran, and Jyothi variety had a better amino acid profile.

1 illus, 5 tables, 34 ref

027142   RANA S S, PRADHAN R C, MISHRA S (Food Process Engineering Dep, National Institute of Technology, Odisha- 769 008, Email: pradhanrc@nitrkl.ac.in) : Variation in properties of tender jackfruit during different stages of maturity. J Food Sci Technol 2018, 55(6), 2122-9.

This research was conducted on two varieties of tender jackfruit [hard (HV) and soft variety (SV)]. The tender jackfruit was divided into four stages (i.e. Stage 1, 2, 3 and 4) and their physical, mechanical, chemical and textural properties were determined for both the varieties. Physical properties like weight, length, diameter, geometric mean and arithmetic mean diameter were increases with increase in size for both the varieties. There was a significant increase in TSS in both the varieties (HV: 1.5 ± 0.02 to 5.1 ± 0.03; SV: 2.7 ± 0.05 to 7.1 ± 0.05 o Brix) from stage 1 to 4 because of ripening of fruit. The hardness, fracturability and springiness increases with maturity but on the counterpart, there is a decrease in adhesiveness, cohesiveness, chewiness and gumminess. The nutritional properties and the energy (kj) values were inevitable increases whereas vitamins content was decreases from stage 1 to 4 in both the varieties. The measured properties will be helpful in planning, design and fabrication of post-harvest processing equipment for tender jackfruits.

6 tables, 26 ref

027141   NOH G, OH H (Ajou Univ, South Korea, Email: hyoh79@gmail.com) : A field study on concurrent spare parts recommendation in an airborne weapon system. Def Sci J 2018, 68(3), 282-9.

As the complexity of weapon systems has grown exponentially during the past few years, initial operation capability has been a crucial factor for military forces. Concurrent spare parts (CSPs) is the quantity of spare parts ensuring initial operating period specified by demanding forces acquiring newly deployed weapon systems. Because of the growth of system complexity, recommending precise CSP is not trivial. The Republic of Korea developed an improved CSP recommendation system and deployed the system for naval weapon systems. In this paper, we increase the prediction accuracy of CSP up to 23.1 per cent and 7.16 per cent higher in terms of budget constraint and operational availability (A_o) constraint. The main improvement is achieved by facilitating simulations using the real field data from Korean air force. Also, we propose two validation approaches and show the possibility of extension to the general weapon systems. From the experimental study, we show that the CSP recommendation system can be deployed for navy and air force

7 illus, 3 tables, 19 ref

027140   RAMAMURTHY N V, VINAYAGAM B K, ROOPCHAND J (DRDO-Combat Vehicles Research and Development Establishment, Chennai - 600 054, Email: nvram2001@gmail.com) : Comfort level refinement of military tracked vehicle crew through optimal control study. Def Sci J 2018, 68(3), 265-72.

Military tracked vehicle and crew are modelled together in this paper as integrated man-machine lumped parameter model, by integrating the simplified 5 degrees of freedom (DoF) tracked vehicle model, including seat and 4 DoF human bio-dynamic model, thus resulting in a 9 DoF simplified vehicle-occupant model. Then the natural frequency of major mass segment namely the chassis mass is obtained through simulation study, for a known road input. The value obtained is compared with that of an earlier research work, for validation of said man-machine model. Then focusing our study locally at crew seat location, parameters of crew seat suspension for ride comfort are optimised using the optimal digital state space controller designed for this purpose by implementing it in a 2 DoF occupant - seat suspension model and its Simulink model constructed. Simulation results illustrate the attainment of the goal by meeting the controller design requirements.

5 illus, 2 tables, 23 ref

027139   HUTTER M, LICHOROBIEC S, SCUREK R (VSB - Technical Univ of Ostrava, Czech Republic, Email: marek.hutter@vsb.cz) : Application of water cumulative charges as a water spouts for intensive flame extinguishing. Def Sci J 2018, 68(3), 260-64.

Shape cumulative charge is a set of explosive components that uses directional energy accumulation. The water cumulative charges are filled with water, which forms a water-directed beam that has the ability to effectively counteract the intense flame that is induced by gaseous flammable gas or liquid from the damaged gas duct and extinguishes it. Study contains description of the experimentally constructed cumulative charge as well as the analysis of results of experiments carried out in real conditions. Based on the facts gained from the experiments we can conclude that the cumulative water charge has a significant potential and possibilities to extinguish an intense flame.

9 illus, 1 table, 9 ref

027138   HEDAYATI E, VAHEDI M (Mechanical Engineering Dep, Islamic Azad Univ, Saveh, Iran, Email: hedayati.uast.ac@gmail.com) : Evaluating impact resistance of aluminum 6061-T651 plate using smoothed particle hydrodynamics method. Def Sci J 2018, 68(3), 251-59.

Performing various experimental, theoretical, and numerical investigations for better understanding of behavioural characteristics of metals under impact loading is of primary importance. In this paper, application of smoothed particle hydrodynamics (SPH) method in impact mechanics is discussed and effective parameters on impact strength of an aluminum plate are investigated. To evaluate the accuracy of smoothed particle hydrodynamics method for simulating impact, Recht and Ipson model is first provided thoroughly for both Rosenberg analytical model and smoothed particle hydrodynamics method, and then plots of initial velocity-residual velocity and initial velocity-absorbed energy for target of aluminum 6061-T651 are presented. The derived information and simulation results expresses that the maximum error percentage of smoothed particle hydrodynamics method in compared with Rosenberg analytical model is within an acceptable range. Therefore, the results of smoothed particle hydrodynamics method verify the Rosenberg analytical model with high accuracy. Results reveal that higher initial impact velocity decreases the time of projectile penetration, and so penetration depth and length as well as the local damage rate of plate increases.

8 illus, 3 tables, 33 ref

027137   SANWALE J, SINGH J D (Aircraft Upgrade Research & Design Centre, Nasik- 422 207, Email: sanwalejitu@gmail.com) : Aerodynamic parameters estimation using radial basis function neural partial differentiation method. Def Sci J 2018, 68(3), 241-50.

Aerodynamic parameter estimation involves modelling of force and moment coefficients and computation of stability and control derivatives from recorded flight data. This problem is extensively studied in the past using classical approaches such as output error, filter error and equation error methods. An alternative approach to these model based methods is the machine learning such as artificial neural network. In this paper, radial basis function neural network (RBF NN) is used to model the lateral-directional force and moment coefficients. The RBF NN is trained using k-means clustering algorithm for finding the centers of radial basis function and extended Kalman filter for obtaining the weights in the output layer. Then, a new method is proposed to obtain the stability and control derivatives. The first order partial differentiation is performed analytically on the radial basis function neural network approximated output. The stability and control derivatives are computed at each training data point, thus reducing the post training time and computational efforts compared to hitherto delta method and its variants. The efficacy of the identified model and proposed neural derivative method is demonstrated using real time flight data of ATTAS aircraft. The results from the proposed approach compare well with those from the other.

8 illus, 1 table, 43 ref

027149   ZHANG W, WANG H, XU J, LIU G, XIE H, YANG L (Guilin Univ of Electronic Technology, Guilin 541004, People’s Republic of China, Email: wh65@guet.edu.cn) : Rectifying resistance-switching behaviour of Ag/SBTO/STMO/p⁺-Si heterostructure films. Bull Mater Sci 2018, 41(3), 70.

The Sr_0.88Bi_0.12TiO₃/SrTi_0.92Mg_0.08O₃ (SBTO/STMO) heterostructure films were prepared on p⁺-Si substrates by sol–gel spin-coating technique, and the films had good crystallinity and uniform grain distribution. The heterostructure films with a structure of Ag/SBTO/STMO/p⁺-Si exhibited a bipolar, remarkable resistance-switching characteristic, and R_HRS/R_LRS ∼10⁴. More importantly, the heterostructure films showed rectifying characteristic in the low resistance state (LRS), and the rectification ratio can reach 10² at ±1 V. The dominant resistive-switching conduction mechanism of high resistance state (HRS) was Ohmic behaviour, and the LRS changed to space charge-limited current (SCLC).

6 illus, 19 ref

027148   SEMNANI D, POURSHARIFI N, BANITABA N, FAKHRALI A (Textile Engineering Dep, Isfahan Univ of Technology, Iran, Email: d_semnani@cc.iut.ac.ir) : Electrospun polyvinylidene pyrolidone/gelatin membrane impregnated with silver sulfadiazine as wound dressing for burn treatment. Bull Mater Sci 2018, 41(3), 72.

Nanofibrous membranes used for burn treatment have become widely popular due to their large surface area and high porous structure. In this study, electrospinning was used to fabricate a blended nanofibrous membrane of polyvinylidene pyrolidone (PVP) and gelatin, to use as wound dressing. The physical and mechanical properties of this novel membrane were investigated using SEM, FTIR and tensile tests. Results showed that poor mechanical properties of gelatin, which are preferred in medical applications for curing burns as they allow for antigen activity and skin repair, can be enhanced by adding PVP in the solution. Silver sulfadiazine (AgSD), an antibacterial agent, was also impregnated into the PVP/gelatin nanofibrous structure during electrospinning. The membrane thus fabricated showed antibacterial activities against both the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. AgSD release behaviour of fabricated samples indicated short-term drug delivery. It was concluded that the proposed drug-loaded membrane can be used as wound dressing, specifically, in treating skin burns.

6 illus, 3 tables, 31 ref

027147   NIAKII M H, FEREIDOON A, AHANGARI M G (Mechanical Engineering Dep, Mazandaran Univ, 57416-13534 Babolsar, Iran, Email: ghorbanzadeh.morteza@gmail.com) : Effect of basalt, silica sand and fly ash on the mechanical properties of quaternary polymer concretes. Bull Mater Sci 2018, 41(3), 69.

The aim of this study is to manufacture quaternary polymer concretes (PCs) and optimize the weight percentages of the epoxy resin, ultrafine fly ash, silica sand and basalt aggregates. For this, we first manufactured binary PCs of epoxy/basalt, epoxy/silica sand and epoxy/fly ash and then studied the mechanical properties such as compressive, flexural and splitting tensile strength. The mixture design method was used as an approach for design of experiment to reduce the number of tests and optimize the mechanical strength of the PC. The best weight percentages of the PC components were 25 (epoxy), 5 (fly ash), 52.5 (silica sand) and 17.5 (basalt). The compressive, flexural and splitting tensile strength of the quaternary PC were equal to 94.1, 39.0 and 11.8, which were 3.76, 11.1 and 6.5 times higher than those of ordinary Portland cement, respectively. Finally, a scanning electron microscopy test was implemented to study the microstructure of the PC.

11 illus, 6 tables, 31 ref

027144   WAHAB R, MOKHTAR N, GHAMI R S M, SULAIMAN M S, SAMSI H W (Technology Sarawak Univ Coll, Sibu- 96000, Sarawak, Malaysia) : Changes in strength characteristics and durability on 4-year-old tropical bamboo Gigantochloa scortechinii through heat treatment. Asian J Sci Technol 2018, 9(5), 8227-33.

The effect of heat treatment on tropical bamboo Gigantochloa scortechinii on the physical, strength and durability were studied. Matured bamboo culms of 4-year-old culms were harvested and subjected to high-temperature condition using palm oil as a heating media. Two group of samples; green and air dried were used in the studies. The temperature applied were 140 °C, 180 °C and 220 °C with an exposure duration of 30, 60 and 90 min respectively. The results show the heat treated bamboo retained most of their original physical and strength properties after undergoing the heat treatments process. Green or air-dried bamboo culms can be dried to an MC of 6-7 % within 2 to 3 hours of treatment. The basic densities of bamboo were found to improve slightly by the heat application. The overall strength properties of the heat treated bamboo were found to decrease. The modulus of elasticity in bending strength was reduced between 2-33 % in the green condition and between 6-9 % in the air-dried condition. For the modulus of rupture in bending strength, the value was reduced between 1-23 % in green condition and between 4-16 % in air-dried condition. The compression strength was reduced in the range between 2-3 % in green and 2-35 % in air-dried conditions. The shear strength was reduced in the range between 16-24 % in green and between 12 to 24 % in air-dried conditions.

11 tables, 23 ref

027143   SREENQMMA B, KUMAR U, SAI N L, NAGA R M, NAGESWQARA R V (Chemical Engineering Dep, Andhra Univ, Visakhapatnam– 530 003) : Mass transfer in circular pipe using square grooved cleaved disc as Turbulence promoter. Asian J Sci Technol 2018, 9(05), 8160-4.

The present study comprises of the evaluation of mass transfer rates at the outer wall of the electrochemical cell. Mass transfer coefficients were evaluated from the measured limiting currents technique. The study covers the influence of various diameters of the disc (D_d), thickness of disc (T_d) and positions of disc (h). The results have revealed that the mass transfer coefficient increases with increase in velocity, diameter of the disc (D_d), thickness of disc (T_d) and decreases with increase in distance of disc from entrance of the test section (h). Within the range of variables covered, the augmentations achieved in mass transfer coefficients were up to 2.08 fold over the tube flow in absence of a promoter. Mass transfer rates were analyzed with mass transfer roughness function and roughness Reynold`s number. The correlation achieved is J_D = 128.40(Re⁺)^-0.9753 ($\mathrm{\varphi }$1)^0.9224($\mathrm{\varphi }$2)^0.1785 ($\mathrm{\varphi }$3)^0.4109.

9 illus, 20 ref

025847   RAO T P, PRASAD P R, SUJATHA V (Chemical Engineering Dep, Andhra Univ, Visakhapatnam- 530 003, Email: pentaraotamarba@gmail.com) : Process intensification with coaxially placed entry region vanes assembly turbulence promoter in homogeneous flow. Indian Chem Eng 2018, 60(2), 162–78.

The entry region vane turbulence promoters are inserted at the downstream of a circular electrolytic cell and limiting current data are measured at the copper micro electrodes fixed on an electrode support. The effect of flow rate of the electrolyte, effect of velocity on mass transfer at the wall, effects of geometric parameters diameter of the vane (d_v) from 0.02 m to 0.04 m, the angle of the vane (γ) from 15° to 60°, sectorial angle (α)/number of the vanes (N) from 4 to 8, diameter of the annular rod of mass transfer is investigated. The electrolyte was equimolal potassium ferricyanide, potassium ferrocyanide and excess sodium hydroxide. Limiting current data had been obtained for the reduction of potassium ferricyanide ion. The mass transfer correlation is based on the law of the wall similarity. The effect of each parameter was studied in terms of friction factor. A model was developed for mass transfer. The correlation may be extended to a wider range of parameters by virtue of the law of the wall. The experimental data on mass transfer was modelled in terms of mass transfer function and Reynolds number geometric parameters.

12 illus, 1 table, 18 ref

025842   OJO O O, TABAN E (Kocaeli Univ, Kocaeli, Turkey, Email: ojooladimeji90@yahoo.com) : Hybrid multi-response optimization of friction stir spot welds: Failure load, effective bonded size and flash volume as responses. Sadhana 2018, 43(6), 98.

Friction stir spot welding (FSSW) is a multi-input multi-response process. Effective multi-response optimization of welds is desirable to create welds with a balance of quality responses. In order to eliminate the subjectivity (uncertainty and engineering judgment) with the existing multi-response Taguchi-based Grey relational analysis, principal component analysis (PCA) was integrated into it. The PCA helps in determining the effective optimal weighting values required for the estimation of Grey relational grade (GRG). As a result, tool rotational speed, plunge depth and dwell time were employed as input parameters while failure load (FL), expelled flash volume (EFV) and effective bonded size (EBS) of conical pin friction stir spot-welded joint of AA2219-O alloy were the chosen output responses. EFV was minimized while FL and EBS of the joints were maximized using this hybrid multi-response approach. From the analysis of variance of GRG and its response graphs, the significant parameters and their levels were obtained. Experimental results confirmed the effectiveness and robustness of this method. In addition, three critical zones were observed on the fracture surfaces of joints, namely, tool impelled unbonded zone, partially bonded zone and effective bonded/nugget zone. The weld nugget failed by circumferential nugget shear mode.

6 illus, 15 tables, 36 ref

025840   KULKARNI P, DHOBLE A, PADOLE P (Mechanical Engineering Dep, Visvesvaraya National Institute of Technology, Nagpur - 440 010, Email: pravin.kul@gmail.com) : A review of research and recent trends in analysis of composite plates. Sadhana 2018, 43(6), 96.

The use of advance composite materials is increasing in various industrial applications such as renewable energy, transportation, medical devices, etc. As the demand for stability under high mechanical, thermal, electrical and combined loads is increasing, research is being focused on developing newer types of composites and developing analytical and numerical methods to study composite plates as well. The present work is aimed to provide a comprehensive review of research in the structural analysis of composite plates along-with research trends in the last 15 years. The article first presents the evolution of plate theories comparing their formulations, applicability and discusses some key papers, results and conclusions. Evolution of research from the equivalent shear deformation theories (ESL) such as first order theory and higher order theories based on various shape strain functions e.g., polynomial, trigonometric to layer-wise, zigzag and displacement potential theories is presented. The comparative analysis of various solution approaches is done based on a review of research work in the structural analysis of plates. This is followed by review of meshless analysis methods for composite materials highlighting problem domains where conventional finite element analysis (FEA) approach has limitations. This article also presents a discussion on the new methods of plate analysis such as region-by-region modeling, hierarchic modeling and mixed FE and neural network based modeling. An attempt has been done in this article to focus on research trends in the last 15 years.

3 illus, 4 tables, 178 ref

025839   BHAJANA V V S K, DRABEK P, JARA M (Kalinga Institute of Industrial Technology Unv, Bhubaneswar - 751 024, Email: kumarbvvs@yahoo.co.in) : Design and analysis of a full bridge LLC DC-DC converter for auxiliary power supplies in traction. Sadhana 2018, 43(6), 95.

This paper focuses on an 8 kW LLC resonant full bridge DC-DC converter topology using a high frequency transformer for auxiliary power supply systems in traction. The full bridge DC-DC converter with the LLC resonant network has been tested under hard switching and zero current switching conditions with 100 kHz switching frequency. In addition to this, an observation made for the effect of dead time variation of the power switches to improve the overall system efficiency. This paper describes the efficiency of the ZCS full bridge converter by considering different input power levels and also compared with hard switched topology. This paper presents the operating principles, simulation analysis, and experimental verification for 3 kW to 8 kW LLC resonant full bridge converter with 1200 V/40 A IGBTs, and its efficiency comparison.

13 illus, 3 tables, 11 ref

025837   SCHMIEDEKE P, BHUIYAN M A S, REAZ M B I, REAZ T G, CHANG T G, CRESPO M L, CICUTTIN A (Electrical and Electronics Engineering Dep, Xiamen Univ Malaysia, Sunsuria, 43900 Sepang, Selangor, Malaysia, Email: arifsobhan.bhuiyan@xmu.edu.bd) : A fully integrated high IP1dB CMOS SPDT switch using stacked transistors for 2.4 GHz TDD transceiver applications. Sadhana 2018, 43(6), 94.

A transmit/receive (T/R) switch is an essential module of every modern time division duplex (TDD) transceiver circuit. A T/R switch with high power handling capacity in CMOS process is difficult to design due to capacitive coupling of radio frequency signals to the substrate. This paper proposes a single-pole-doublethrow (SPDT) T/R switch designed in a standard Silterra 130 nm CMOS process for high-power applications like RFID readers. The results reveal that, in 2.4 GHz ISM band, the proposed switch exhibits a very high input P1dB of 39 dBm with insertion loss of only 0.34 dB and isolation of 40 dB in transmit mode but 1.08 dB insertion loss and 30 dB isolation in receive mode. Stacked thick-oxide triple-well transistors, resistive body floating and negative control voltages are used to achieve such lucrative performance. Moreover, the chip size of the designed switch is only 0.034 mm² as bulky inductors and capacitors are avoided. The Monte-Carlo and corner analyses confirm that the performance of the switch is also quite stable and reliable.

9 illus, 3 tables, 24 ref

025836   PRABHAKAR D K, PAL S (Computer Science and Engineering Dep, Indian Institute of Technology (Indian School of Mines), Dhanbad - 826 004, Email: dinesh.nitr@gmail.com) : Machine transliteration and transliterated text retrieval: A survey. Sadhana 2018, 43(6), 93.

Users of the WWW across the globe are increasing rapidly. According to Internet live stats there are more than 3 billion Internet users worldwide today and the number of non-English native speakers is quite high there. A large proportion of these non-English speakers access the Internet in their native languages but use the Roman script to express themselves through various communication channels like messages and posts. With the advent of Web 2.0, user-generated content is increasing on the Web at a very rapid rate. A substantial proportion of this content is transliterated data. To leverage this huge information repository, there is a matching effort to process transliterated text. In this article, we survey the recent body of work in the field of transliteration. We start with a definition and discussion of the different types of transliteration followed by various deterministic and non-deterministic approaches used to tackle transliteration-related issues in machine translation and information retrieval. Finally, we study the performance of those techniques and present a comparative analysis of them.

1 illus, 5 tables, 128 ref

025835   GANJI P R, SINGH R N, V R K RAJU, RAO S S (Mechanical Engineering Dep, National Institute of Technology, Warangal - 506 004, Email: ganjiprabhakar@gmail.com) : Design of piston bowl geometry for better combustion in direct-injection compression ignition engine. Sadhana 2018, 43(6), 92.

The current computational fluid dynamics (CFD) study presents the effect of piston bowl geometry on the performance and emissions of a direct-injection diesel engine. Different piston bowl profiles, namely, hemispherical combustion chamber (HCC), shallow depth combustion chamber (SCC) and toroidal combustion chamber (TCC), have been created with a baseline compression ratio of 17.5. CONVERGE^TM CFD code coupled with the SAGE combustion model was used for numerical analysis. It is observed that the TCC piston bowl geometry renders better air–fuel mixture inside the cylinder, which leads to a homogeneous charge. Further, numerical experiments are carried out to analyze suitable TCC piston bowl geometry by varying the depth of the bowl. Out of all the cases, the case with 1.26 mm decrease in depth of bowl from the baseline (TCC) design gives better emissions and performance characteristics.

20 illus, 4 tables, 29 ref

025834   SONIKA, NEEMA D D, PATEL R N (Electronics and Communication Engineering Dep, Chhatrapati Shivaji Institute of Technology, Chhattisgarh - 491 001, Email: sonika444@gmail.com) : Design and implementation of sigma-delta digital to analog converter. Sadhana 2018, 43(6), 91.

This paper presents the design and implementation of a 16-bit sigma–delta digital to analog converter (DAC) for audio applications. In order to achieve high-order noise shaping without the stability problem inherent in the design of higher order loop, cascade structure may be used. One of the drawbacks in a multi-bit cascaded sigma delta modulator is the un-cancelled noise and the nonlinearity error. The idea of the proposed architecture is to present an improved version of cascaded multi-bit sigma–delta modulator to overcome these problems. Simulation results verify the superiority of the proposed modulator. Sampling rate conversion plays a predominant role in the signal processing and has a strong influence on the overall complexity and cost of efficient sigma–delta DAC. In this paper a technique to examine filter architectures that can be effectively applied in the interpolator design is also presented; the sigma–delta modulator design is implemented on a field programmable gate array (FPGA) for verification purpose and results are presented.

17 illus, 6 tables, 10 ref

025833   SINGH S, REPAKA R (Mechanical Engineering Dep, Indian Institute of Technology Ropar, Rupnagar - 140 001, Email: ramjee.repaka@gmail.com) : Numerical investigation of convective cooling in minimizing skin burns during radiofrequency ablation of breast tumor. Sadhana 2018, 43(6), 90.

Skin burns is one of the most common complications reported during treatment of early-stage breast cancer with radiofrequency ablation (RFA) technique. In this regard, the present study aims to analyze the efficacy of forced convection surface cooling in minimizing the skin burns during RFA of breast tumor. The study considers a heterogeneous three-dimensional numerical model of breast that has been constructed based on the anatomical details available in the literature. A spherical tumor of 1.5 cm has been embedded in the numerical model of breast to represent in-situ tumor in its early stage. A programmable temperature-controlled RFA has been performed by incorporating the closed-loop feedback PID controller into the numerical model. The thermo-electric analysis has been performed using a finite element based commercial solver COMSOL Multiphysics to obtain the temperature distribution by incorporating the coupled electric field distribution, Pennes bioheat equation and Arrhenius rate equation. The temperature dependent electrical and thermal conductivities of both the tissue and tumor along with damage dependent perfusion rate have been incorporated to achieve better correlation with the clinical RFA. The numerical simulation results revealed that, there is a significant reduction in the temperature at outer periphery of breast with increase in convective heat transfer coefficient. Further, the effects of variation in surface cooling on temperature distribution, input voltage requirement and treatment time required for complete tumor necrosis have been studied. The simultaneous application of forced convective surface cooling along with RFA could play a vital role in addressing the most common complication of skin burns during treatment of breast cancer.

8 illus, 2 tables, 26 ref

025832   BEKAL C, SHETTY R, SHENOY S (Aeronautical and Automobile Engineering Dep, Manipal Univ, Manipal, Email: satish.shenoy@manipal.edu) : Numerical investigation of influence of number of stent cells and type of link on expansion and haemodynamic behaviour of balloon-expandable coronary stent. Sadhana 2018, 43(6), 88.

Coronary stents are tubular, mesh-like structures used to force open clogged artery. Mounted on an inflatable balloon, stent compresses calcified plaque inside atherosclerotic artery with an inflating device, which transfers the load through the compliant balloon, thus maintaining the patency of lumen. One of the contributors for success of angioplasty is type of stents, which mainly differs in its geometrical design. A clinician recommends a stent based on comparative advantages. An ideal stent should be flexible to manoeuver through tortuous artery, easy to expand, provide good scaffolding to the vessel, have less radial recoil and foreshortening, possess uniformity in expansion and induce minimum alteration in physiological blood flow dynamics. In a stent these parameters are in competition with each other and are optimized by trade-offs. The present work tries to sequentially investigate the effect of number of stent cells and type of links on the expansion and haemodynamics behaviour through computational analysis based on finite element and finite volume techniques. The study compares performance within same classes of designs rather than comparing the designs that are completely different form each other. Results show that more number of stent cells in longitudinal direction considerably decrease the radial recoil, but increase the foreshortening effect. Restenosis-prone zones are localized around the stent struts and are predominant during end of systolic phase of cardiac cycle. Shorter links are preferred for better recoil and favourable distribution of wall shear stress while longer links are preferred for favourable foreshortening.

16 illus, 6 tables, 49 ref

025831   AGARWAL V, KUMAR P (Thapar Institute of Engineering and Technology, Patiala - 147 001, Email: vaibhavagg123@gmail.com) : UNLization of Punjabi text for natural language processing applications. Sadhana 2018, 43(6), 87.

During the last couple of years, in the field of Natural Language Processing, UNL (i.e., Universal Networking Language) immense research activities have been witnessed. This paper illustrates UNLization of Punjabi Natural Language for UC-A1, UGO-A1, and AESOP-A1 with IAN (i.e., Interactive Analyzer) tool using X-Bar approach. This paper also discusses the UNLization process in depth, step-by-step with the help of tree diagrams and tables.

18 illus, 9 tables, 54 ref

025830   BALAPRAKASH V, GOWRISANKAR P, RAJKUMAR R, SUDHA S (Hindusthan College of Arts and Science, Coimbatore - 641 028, Email: km.balaprakash@gmail.com) : Preparation and characterization of aluminum doped zinc oxide (AZO) nanorods. Sadhana 2018, 43(6), 86.

Aluminum doped Zinc Oxide (AZO) nanorods with 1at. % aluminum content were prepared by Solgel spin coating technique. The structural and topographical properties are studied using X-Ray Diffraction (XRD) technique and Atomic Force Microscopy (AFM), respectively. Higher intensity Zinc Oxide (ZnO) peak (002) is observed in 1at. % aluminum doped nanorod with 50 s spin coated sample underwent 300⁰ C of annealing temperature. Morphologic, compositional and crystallographic information of the samples are predicted using Transmission Electron Microscopy (TEM), the 600 nm long nanorod with an aspect ratio of 10 is obtained for 20 s and 50 s spin coating time.

4 illus, 11 ref

025829   MISRA H, JAIN A K (Electrical Engineering Dep, Indian Institute of Technology Delhi, New Delhi - 110 016, Email: himanshu00129@gmail.com) : Harmonics reduction in standalone DFIG-DC system by shunt active filter controlled in stator flux reference frame. Sadhana 2018, 43(6), 85.

The presence of diode rectifier in standalone Doubly Fed Induction Generator-Direct Current (DFIGDC) system leads to considerable current, voltage and torque harmonics and requires reactive power from the machine. A unique shunt active filter arrangement is proposed for addressing these requirements. The DC Link of DFIG-DC itself acts as input to shunt active filter and there is no requirement of creating and regulating a separate one. Since the stator flux reference frame is known in FOC of DFIG-DC system; the same can be used as PLL for the generation of current references for harmonics and reactive compensation in active filter control scheme. Hence, the AC voltage sensing is not needed in the proposed active filter control. In this paper, it is shown that current, voltage and torque harmonics are reduced with the help of shunt active filter, which have lower rating compared to the rotor side converter. The proposed scheme is verified by detailed experiments on a 5.5 kW slip-ring induction machine.

9 illus, 24 ref

025828   SARDOUEI M M, MORTEZAPOUR H, NAEIMI K J (Biosystems Engineering Dep, Shahid Bahonar Univ of Kerman, Kerman, Iran, Email: mohammadimasoud.s90@gmail.com) : Temperature distribution and efficiency assessment of different PVT water collector designs. Sadhana 2018, 43(6), 84.

The aim of this work was to study different hybrid photovoltaic-thermal (PVT) collectors. Numerical simulation of the collectors was carried out using a 3-dimensional computational fluid dynamic (CFD) model. A set of experiments was conducted using a box-type PVT collector to validate the obtained computed data. Simulation results for water outlet temperature, especially at the lower flow rates, were closer to the measured data compared with average module surface temperature. Based on the simulation results, the spiral flow designs of heat exchanger provided the most uniform temperature distribution for module surface and the highest temperature gradient was observed with the direct flow designs. A hot zone was generated on the module surface of the direct flow box-type collector and the results indicated that the hot zone was considerably declined using cross-fins inside the box-type heat exchanger. The highest heat transfer to the ambient occurred with the spiral flow design and the box type heat exchanger presented a relatively low heat losses. The cross-fined box type and the spiral flow designs of the PVT collector had the highest electrical efficiencies at the different test conditions.

10 illus, 5 tables, 40 ref

025827   ZARALI F, YAZGAN H R, DELICE Y (Industrial Engineering Dep, Sakarya University, 38300 Kayseri, Turkey, Email: fzarali@erciyes.edu.tr) : A new solution method of ant colony-based logistic center area layout problem. Sadhana 2018, 43(6), 83.

In today’s world, logistic centers not only play an important roles in sustaining the nation’s economy, they also significantly contribute to the economic and social development of the regions in which they are located. The layout of the center is crucial in ensuring that such important centers are both efficient and productive. To achieve this, this study focuses on the development of a logistic center layout that is integrated with the ant colony optimization algorithm. To this end, the logistic center area layout was developed by applying the developed algorithm to an actual logistic center planned to be constructed. The efficiency of the suggested algorithm was tested in accordance with the benchmark problems in the literature. In addition, a case study was carried out to illustrate the effectiveness of the proposed approach. The obtained results revealed that the suggested algorithm provided more efficiency than other layouts.

11 tables, 32 ref

025826   PRASHANTHA B G, GOWDA M S G, SEETHARAMU S, NARASIMHAM G S V L (Industrial Engineering and Management Dep, JSS Academy of Technical Education, Bangalore - 560 060, Email: bgpsandur@gmail.com) : Design and analysis of acoustically-driven 50 W thermoacoustic refrigerators. Sadhana 2018, 43(6), 82.

The design of loudspeaker-driven 50 W cooling power thermoacoustic refrigerators operating with helium at 3 % drive-ratio and 10 bar pressure for a temperature difference of 75 K using the linear thermoacoustic theory is discussed. The dimensional normalization technique to minimize the number of parameters involved in the design process is discussed. The variation in the performance of the spiral stack-heat exchangers’ at 75 % porosity as a function of the normalized stack length and center position is discussed. The resonator optimization is discussed, and the optimized one-third-wavelength (tapered, small diameter tube and divergent section with hemispherical end), and one-fourth-wavelength (tapered and divergent section with hemispherical end) resonator designs show 41.3 % and 30.8 % improvements in the power density compared to the published 10 W designs, respectively. The back volume gas spring system for improving the performance of the loudspeaker is discussed. The one-third-wavelength and one-fourth-wavelength resonator designs are validated using the DeltaEC software, which predicts the cold heat exchanger temperature of - 3.4 C at 0.882 COP, and - 4.3 C at 0.841 COP, respectively.

6 illus, 10 tables, 23 ref

025825   YADAV A K, CHANDEL S S (Electrical and Electronics Engineering Dep, National Institute of Technology, South Sikkim - 737 139, Email: amit1986.529@rediffmail.com) : Formulation of new correlations in terms of extraterrestrial radiation by optimization of tilt angle for installation of solar photovoltaic systems for maximum power generation: Case study of 26 cities in India. Sadhana 2018, 43(5), 81.

This paper deals with finding of optimum tilt angle for installation of optimized solar photovoltaic system in India. The optimization of tilt angles is performed using measured solar radiation data for 26 cities in India. The tilt angle is changed from 0 ⁰ to 90 ⁰ at step of 1⁰ to find out optimum tilt angle for which monthly average solar radiation is maximum. It was found that the optimum tilt angle varies between 0 ⁰ and 63 ⁰ throughout the year in India. The monthly optimum tilt angle is maximum in December for all cities in India. It is found that increase in maximum solar radiation at monthly optimum tilt angle in comparison to latitude based tilt angle and annual optimum tilt angle varies from 5.85 % to 8.08 % and 5.95 % to 8.34 %, respectively, showing monthly optimum tilt angle is beneficial for maximum power generation for different cities in India. The novelty of this study is new correlations of optimum tilt angle in terms of extraterrestrial radiation are developed for estimating monthly optimum tilt angle for installation of photovoltaic systems at different sites in India. The root mean square error in correlation equations varies from 0.1256 to 0.9771.

4 illus, 5 tables, 45 ref

025824   CHEN B, ZHANG L, CHEN X, ZHANG Q (Chongqing Univ, Chongqing 400044, People’s Republic of China, Email: 20153201011@cqu.edu.cn) : Thermodynamic and numerical analysis of intake air humidification of a turbocharged GDI engine. Sadhana 2018, 43(5), 79.

Reducing the temperature and increasing the specific heat capacity of working medium of gasoline engines are the most efficient methods of mitigating knock tendency. The charge cooling effect of intake air humidification is helpful for decreasing the initial temperature of intake air, and the increase of the specific heat capacity of working medium can reduce the temperature rise in the in-cylinder process. This study established a mathematical model of intake air humidification of gasoline engines, and analyzed the effects of the technique on the thermodynamic process of a turbocharged gasoline engine with Ricardo WAVE Code. The results indicated that the intake air humidification is an isenthalpic process; the vapor influences the working process of the engine by altering the thermodynamic parameters of the working medium. A decrease in the initial temperature and adiabatic index and an increase in the specific heat capacity of working medium lowered the incylinder temperature and pressure, hence suppressing the knock occurrence. After the humidification of intake air, the engine performance slightly increased, and the thermal efficiency showed different levels of improvements at all the working conditions.

15 illus, 2 tables, 18 ref

025823   KUMAR P, PANDA S K (Mechanical Engineering Dep, Indian Institute of Technology Patna, Patna, Email: pintu.pme13@iitp.ac.in) : A review on properties and microstructure of micro-extruded product using SPD and as-cast material. Sadhana 2018, 43(5), 77.

Micromanufacturing has wide application in the development of micro-products, but these methods are limited in developing desired properties such as dimensional tolerance, surface texture and electromechanical properties. Deformation is one of the techniques where such limitations on micro-products can be overcome based on the principle of grain refinement theory. The product developed through subtractive and additive method reveals coarse grain microstructure, whereas ultrafine grains (UFGs) are observed in the severe plastic deformation (SPD) process. Equal-channel angular pressing (ECAP) is one of the best SPD techniques to produce UFG up to a nanometre. As-cast micro-extruded product that contains coarse grains seems to be inhomogeneous, having wide deviation of physical and mechanical properties throughout its volume. ECAP-based micro-extruded product is homogeneous and has uniform physical and mechanical properties. The present review paper discusses about the influence of die geometry, die strength, specimen selection, frictional condition, temperature condition and other boundary conditions on the properties of as-cast and ECAPed extruded material. Similarly, size and direction of grain can alter the mechanical properties based on requirements and type of applications.

31 illus, 3 tables, 100 ref

025822   SINGH J, SINGH R, SINGH H, VERMA A K (Engineering Dep, Guru Nanak Dev Engineering Coll, Ludhiana - 141006, Email: Rupindersingh78@Yahoo.Com) : Investigations for mechanical properties and biocompatibility of SS-316L implant prepared as rapid investment casting for batch production. Sadhana 2018, 43(5), 76.

In this work, a detailed procedure for the development of biomedical implant (SS-316L) by combining fused deposition modeling (FDM), chemical vapor smoothing (CVS), silicon molding (SM) and investment casting (IC) for batch production has been outlined. In spite of being biocompatible and bioactive within the body, the implant must possess good surface quality and dimensional accuracy along with sufficient hardness in order to reduce the wear inside the body. So in this research work, investigations have been made on the surface finish, dimensional accuracy and hardness of the implants by varying two controllable factors of the IC process (drying time of primary coating and mould thickness). The tolerance grades for the selected dimension of the casted implants were within the allowable range as defined in UNI EN 20286-I (1995) standard of ISO. The process capability indices (Cp and Cpk) values greater than 1.33 for the surface hardness and radial dimension indicated that the proposed process is statistically controlled. Further, in order to evaluate the biocompatibility, an in vitro study was conducted to ensure the attachment of mouse embryonic fibroblasts cells (NIH-3T3) to the casted samples. The results of invitro study indicated that samples were capable of supporting cell adhesion and cell proliferation and hence can be used for tissue engineering.

12 illus, 4 tables, 49 ref

025821   PRAJAPATI P, BADHEKA V J, MEHTA K (Mechanical Engineering Dep, Pandit Deendayal Petroleum Univ, Gandhinagar- 382 007, Email: kush2312@gmail.com) : An outlook on comparison of hybrid welds of different root pass and filler pass of FCAW and GMAW with classical welds of similar root pass and filler pass. Sadhana 2018, 43(5), 75.

In the present study, gas metal arc welding and flux cored arc welding were applied on SA516 Gr70 carbon steel material. Two different hybrid passes were applied, wherein flux cored wire and solid wire were applied to root pass and filler pass one by one and vice versa. Besides, two more welds of similar electrode root pass and filler pass of flux cored arc welding and gas metal arc welding were acquired. The comparative analysis was carried out in terms of macrostructure and microstructure examination, tensile testing, hardness variations, and impact testing for these classical welds and hybrid welds. The results reveal that, hybrid welds lead to better impact properties relative to classical welds. Maximum angular distortion of 2.66 was reported with classical weld of gas metal arc welding with solid wire root pass and same filler pass. The maximum impact toughness of 49 J/m³ was reported for flux cored root pass and solid wire filler pass at the weld zone. Maximum tensile strength of 596 MPa was reported for hybrid weld of solid root pass and flux cored filler pass. Microstructures are reported with the presence of different acicular ferrite and grain boundary ferrite. Maximum acicular ferrite of 61 % was reported with classical weld of flux cored arc welding.

8 illus, 5 tables, 16 ref

025820   RONALD J A, MENON A, PRASAD A M, MENON D, MAGENES G (Civil Engineering Dep, Indian Institute of Technology, Chennai- 600 036, Email: ajetsonronald@yahoo.co.in) : Modelling and analysis of South Indian temple structures under earthquake loading. Sadhana 2018, 43(5), 74.

The gopuram (multi-tiered entrance gateway) and the mandapam (pillared multi-purpose hall) are two representative structural forms of South Indian temples. Modelling and seismic analysis of a typical 9-tier gopuram and, 4- and 16-pillared mandapam of the 16th century AD Ekambareswar Temple in Kancheepuram, South India, are discussed. The seismic input is based on a probabilistic seismic hazard analysis of the archaeological site. Two modelling strategies, namely lumped plasticity and distributed plasticity modelling, and three analysis approaches, namely linear dynamic, non-linear, static and dynamic analyses were adopted for the seismic assessment of the gopuram. Unlike slender masonry towers, the vulnerable part of the gopuram could be at the upper levels, which is attributable to higher mode effects, and reduction in cross section and axial stresses. Finite element and limit analysis approaches were adopted for the assessment of the mandapam. Potential collapse mechanisms were identified, and the governing collapse of lateral load, calculated based on limit theory, was compared with the seismic demand as a safety check. Simple relations, as a means of rapid preliminary seismic assessment, are proposed for the mandapam.

21 illus, 7 tables, 37 ref

025819   RAMESHCHANDRA P SHIMPI, SHETTY R A, GUHA A (Aerospace Engineering Dep, Indian Institute of Technology, Mumbai - 400 076, Email: rpshimpi@aero.iitb.ac.in) : A single variable shear deformable nonlocal theory for transversely loaded micro- and nano-scale rectangular beams. Sadhana 2018, 43(5), 73.

In this paper, a simple single variable shear deformable nonlocal theory for bending of micro- and nano-scale rectangular beams is presented. To incorporate small size effects, the theory uses Eringen’s nonlocal differential constitutive relations. The theory has only one fourth-order governing differential equation involving a single unknown variable. The governing equation and the expressions for the bending moment and shear force of the present theory are strikingly similar to those of nonlocal Euler-Bernoulli Beam Theory (EBT) formulated based on Eringen’s nonlocal elasticity theory. The theory assumes that the axial and lateral displacements have bending and shear components such that the bending components do not contribute towards shear force, and the shear components do not contribute towards bending moment. Also, the chosen displacement functions of the theory give rise to a realistic parabolic transverse shear stress distribution across the beam cross-section. Efficacy of the proposed theory is demonstrated through bending of simply supported, cantilever and clamped-clamped micro- and nano-scale beams of rectangular cross-section. The numerical results obtained by using the present theory are compared with those predicted by other nonlocal first-order and higher-order shear deformation beam theories. The results obtained are quite accurate.

4 illus, 39 ref

025818   NAVAMANI J D, JEGATHEESAN R, VIJAYAKUMAR K (EEE Dep, SRM Univ, Kattankulathur- 603203, Email: divyateddy1@gmail.com) : Reliability study of high gain DC-DC converters based on RRPP I-IIA configuration for shipboard power system. Sadhana 2018, 43(5), 71.

This paper examines the family of high gain DC-DC converter derived from I-IIA configuration, primarily based on Reduced Redundant Power Processing (RRPP). The primary intention of this study is to determine the best topology for high voltage applications. The steady-state analysis of the proposed topologies is investigated and verified. The denominators of the voltage conversion ratio are observed to be similar for all the derived topologies, and they are in quadratic form. A comprehensive assessment is done based on voltage gain, voltage stress across storage element, switch stress voltage, switch utilization factor and inductor value. The best topology is identified and analyzed thoroughly in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Also, its performance evaluation and reliability study are also carried out. The advantage of that topology is validated using theoretical and simulation results. Finally, 40 W prototype is developed to verify the results.

16 illus, 5 tables, 19 ref

025817   GOSTIMIROVIC M, KOVAC P, SEKULIC M (Production Engineering Dep, Novi Sad Univ, Serbia, Email: maring@uns.ac.rs) : An inverse optimal control problem in the electrical discharge machining. Sadhana 2018, 43(5), 70.

Electrical discharge machining (EDM) is a thermal material removal process by means of electrical discharge. Because of the stochastic nature of the EDM process, electro-thermal energy conversion in the discharge zone is still not well understood. In this paper, an inverse optimal control problem was used for analysis and optimization of energy conversion processes in order to improve machining efficiency. Modeling and identification of a thermal process were conducted using the inverse heat transfer problem based on the known temperature within a workpiece. In addition to the temperature field, this approach allows the determination of unknown heat flux density distribution on the workpiece surface. By using the heat flux, the inverse optimal control problem based on minimizing a Tikhonov functional allows to obtain the optimal heat source parameters (discharge power and discharge duration) on the discharge energy. In this context, the concept of inverse problem allows reliable determination of the optimal discharge energy to achieve the highest possible productivity with the desired quality. The performance of prediction of the heat affected zone compared to the experimental results showed a good agreement, which confirms the validity of the inverse method compared to the reported models.

8 illus, 1 tables, 31 ref

025816   AGHAJANI H F (Civil Engineering Dep, Azarbaijan Shahid Madani Univ, Iran, Email: h.farshbaf@azaruniv.ac.ir) : The effect of embedded gypsum streaks on the dissolution of dam foundation: A case study in Iran. Sadhna 2018, 43(5), 69.

Evaporative rocks are known to have a high susceptibility to dissolution in fresh water. Substantial evidence all over the world has shown that the dissolution of evaporative rocks in the foundations of dams and basins can lead to unfortunate disasters. In a basin located in Iran, owing to dissolution of evaporative rock in the foundation on the south side, some hazardous events, such as unexpected subsidence, ground collapse, and water escape from the reservoir, have been reported. Comprehensive geological and geophysical surveys along with detailed geotechnical investigations were performed in order to assess the reasons. By analyzing the site investigation results, it is recognized that even though the foundation of the basin is composed of impervious marl layer, the dissolution of thin streaks of gypsum embedded inside the marl layer provides interconnected paths for the flow of water into the lower depths of the foundation in order to reach to halite layer located inside the marl. The geophysical survey results indicate that the zone with defects is limited to the specific area of the basin where the halite layer is located relatively near the ground surface. However, if the reservoir is filled completely again, the dissolution front may advance to other zones of the basin, and more area of the basin ground may be affected by subsidence and other relevant phenomena.

16 illus, 2 tables, 20 ref

025815   NATARAJ C, KHAN S, HABAEBI M H (Electrical and Computer Engineering Dep, Asia Pacific Univ of Technology and Innovation, Malaysia, Email: chander@apu.edu.my) : Coil geometry models for power loss analysis and hybrid inductive link for wireless power transfer applications. Sadhana 2018, 43(5), 67.

This paper presents a hybrid inductive link for Wireless Power Transfer (WPT) applications. Achieving better power transfer efficiency over a relatively wider distance across coils is the prime objective in most of the WPT systems, but often suffers from power loss in the near field area of inductively coupled coils. One of the reasons for this power loss is the pattern of the magnetic field produced by the source coil used in the WPT system. Mostly the nature of magnetic field produced by the source coil is distributed radially over the coil, in which the produced magnetic field is not fully utilized. Achieving better efficiency and load current by reducing power loss is the main driving force of this work. One of the viable methods to reduce the power loss is by increasing the field intensity thereby redirecting the flux lines flow to be directional. With this aim, three coils such as solenoid, spiral and conical are designed and simulated to determine the magnetic field strength using Finite Element Method. The conical coil produces the highest self-inductance of 8.63 lH and a field strength of 1.542 Wb with the coil thickness of 3.20 mm. Then, WPT system is demonstrated with the inclusion of Maximum Power Point Tracking algorithm for improving efficiency. The schematic of flux generation of both in the transmitter and receiver sections are demonstrated and analyzed graphically. The efficiency of both simulation and experimental measurements are matched well with similar progression. The effect of parameters (angle, distance, and load resistance) on the efficiency is explored. The outcomes conclude that the inductive coupling has achieved 73 % (average case) power transfer wirelessly over a distance of 5 cm with an input voltage of 5 V and 5 MHz frequency.

10 illus, 2 tables, 24 ref

025808   TURGUT AK, AYDEMIR T, SAHA A, KARA A H (Transportation Engineering Dep, Yalova Univ, Yalova - 77100, Turkey, Email: akturgut@yahoo.com) : Propagation of nonlinear shock waves for the generalised Oskolkov equation and its dynamic motions in the presence of an external periodic perturbation. Pramana - J Phys 2018, 90(6), 0078.

Propagation of nonlinear shock waves for the generalised Oskolkov equation and dynamic motions of the perturbed Oskolkov equation are investigated. Employing the unified method, a collection of exact shock wave solutions for the generalised Oskolkov equations is presented. Collocation finite element method is applied to the generalised Oskolkov equation for checking the accuracy of the proposed method by two test problems including the motion of shock wave and evolution of waves with Gaussian and undular bore initial conditions. Considering an external periodic perturbation, the dynamic motions of the perturbed generalised Oskolkov equation are studied depending on the system parameters with the help of phase portrait and time series plot. The perturbed generalised Oskolkov equation exhibits period-3, quasiperiodic and chaotic motions for some special values of the system parameters, whereas the generalised Oskolkov equation presents shock waves in the absence of external periodic perturbation.

12 illus, 5 tables, 31 ref

025807   ABDOLMOHAMMADI H, KHALAF A J M, VIET-THANH PHAM, RAJAGOPAL S P K, JAFARI S (Biomedical Engineering, Amirkabir Univ of Technology, Iran, Email: sajadjafari@aut.ac.ir) : A new 4D chaotic system with hidden attractor and its engineering applications: Analog circuit design and field programmable gate array implementation. Pramana - J Phys 2018, 90(6), 0070.

Nowadays, designing chaotic systems with hidden attractor is one of the most interesting topics in nonlinear dynamics and chaos. In this paper, a new 4D chaotic system is proposed. This new chaotic system has no equilibria, and so it belongs to the category of systems with hidden attractors. Dynamical features of this system are investigated with the help of its state-space portraits, bifurcation diagram, Lyapunov exponents diagram, and basin of attraction. Also a hardware realisation of this system is proposed by using field programmable gate arrays (FPGA). In addition, an electronic circuit design for the chaotic system is introduced.

11 illus, 1 table, 66 ref

025805   DEMIR S M, YÜKSEK Y, SABAH C (Electrical and Electronics Engineering Dep, Middle East Technical Univ, Turkey, Email: sabah@metu.edu.tr) : Investigation of graphene-integrated tunable metamaterials in THz regime. Pramana - J Phys 2018, 90(5), 65.

A metallic fishnet metamaterial structure in sub-THz region is presented. The proposed structure is based on hexagonal resonators. Simulations have been performed by a 3D full-wave electromagnetic simulator and a negative refractive index has been observed at the frequency range between 0.55 and 0.70 THz with the help of the graphene layer. In order to observe the effect of the graphene layer, the metamaterial structure has been simulated and examined before and after graphene integration. Significant modification in the propagation properties has been observed after the graphene integration. Change in S-parameters with the size variation of hexagonal resonators and alteration in graphene thickness are also presented as a parametric study to show the tunability of the structure. Suitability of the metamaterial for sensor applications has been investigated. The proposed metamaterial structure is promising to be effectively used for tunability and sensor applications.

18 illus, 33 ref

025804   M AZIMI, GANJI D D, AZIMI A, RIAZI R (Chemical Engineering Dep, Chemical Engineering Coll, Iran, Email: meysam.azimi@gmail.com) : Analytical investigation of unsteady CuO nanofluid flow, heat and mass transfer between two parallel disks. Indian J Chem Technol 2018, 25(3), 281-6.

The heat transfer in the unsteady CuO nanofluid flow between two moving parallel disks has been investigated using analytical method called Galerkin Optimal Homotopy Asymptotic Method (GOHAM). The effect of Brownian motion on heat transfer enhancement has been shown. The analytical investigation is carried out for various governing parameters such as the squeeze parameter, Hartman number, Brownian motion and thermophoretic parameters. The results show that concentration is an increasing function of Brownian motion parameter while it is a decreasing function of the thermophoretic parameter.The comparison of obtained results with numerical solutions assures us about the validity and accuracy of the current study.

5 illus, 1 table, 12 ref

025803   EROL S, OZDEMIR M (Chemical Engineering Dep, Eskisehir Osmangazi Univ, Turkey, Email: mnozdemi@ogu.edu.tr) : Kinetics, equilibrium and thermodynamics studies on Cd(II) removal from aqueous solution by magnesite tailing. Indian J Chem Technol 2018, 25(3), 246-254.

Magnesite tailing for the removal of Cd(II) from aqueous solutions has been investigated using batch process. The effects of various parameters such as initial pH, adsorbent dosage, contact time and temperature on the removal of Cd(II) have been investigated. Kinetic models are applied to describe the adsorption kinetics of Cd(II) onto magnesite tailing. The adsorption kinetics follows well the pseudo second order kinetic model. The Langmuir, Freundlich and D-R isotherm models have been used for the analysis of adsorption equilibrium. The Langmuir isotherm model fits the equilibrium data. The monolayer adsorption capacity of magnesite tailing is found to be 38.46 mg/g at 45 °C. The thermodynamic parameters show that the adsorption process is feasible, spontaneous and endothermic. The Cd(II) - magnesite tailing interactions are confirmed by the Scanning electron microscope (SEM) and the Fourier transform infrared spectroscopy (FTIR). A single stage batch adsorber was designed for different adsorbent dosage using Langmuir isotherm. It is determined that approximately 99 % of Cd(II) from aqueous solution could be removed at a pH value of 6, an adsorbent dosage of 0.3 g / 50 mL solution, a contact time of 24 h, an initial solution concentration of 10 mg/L and a temperature of 25 °C. The results indicate that magnesite tailing could effectively be used for the removal of Cd (II) from aqueous solutions.

9 illus, 6 tables, 43 ref

025802   ASOKAN M A, VIJAYAN R, PRABHU S S (Mechanical Engineering Dep, Government Coll of Engineering, Vellore- 632 014, Tamilnadu, Email: asokan.ma@vit.ac.in) : A review on performance, emission and combustion characteristics of a diesel engine fuelled with various vegetable oil. Indian J Chem Technol 2018, 25(3), 225-34.

In the present scenario, world energy consumption is increasing rapidly every year because of the increasing trend of modernization and industrialization. Crude oil is the major source for producing energy, results in the degradation of the environment due to fossil fuel combustion. Moreover, the combustion products like carbon di-oxide (CO₂), sulphur di-oxide (SO₂), and nitrogen oxide (NOX) causes global warming. Crude oil depletes every year, to satisfy the energy demands, the crude oil is imported. The environmental problems caused by the indiscriminate use and scarcity of petroleum are the major factor to explore renewable energy resources. The idea of vegetable oil as a fuel to run diesel engines has been on the world stage over a century ago. Vegetable oil is an alternative fuel as a source of energy has been receiving great attention among the researchers because of its renewability, biodegradability, non-toxic and better quality of exhaust gas emissions. A lot of edible and inedible vegetable oils which canbe exploited for substitute fuel as diesel fuel, i.e., jatropha, karanja, rubber seed, cottonseed, palm oil, sun flower oil, rape seed oiland neemoils etc., has been selected and discussed the performance, combustion and emission characteristics of diesel engine under the various working conditions.

1 table, 53 ref

025801   BHATIA S, KAUR B, PHUTELA U G, KUMAR P (Processing and Food Engineering Dep, Punjab Agricultural Univ, Ludhiana- 141 004, Email: surekhabhatia@pau.edu) : Kinetic and thermodynamic behavior of partially purified cellobiase from Humicola fuscoatra MTCC 1409. Indian J Biochem Biophys 2018, 55(3), 163-72.

The study was undertaken with the objective to purify and characterize cellulases from thermophilic fungus Humicola fuscoatra in order to find out its potential to increase hydrolysis of lignocellulosic biomass especially paddy straw. Cellobiase, an important component of cellulase enzyme complex, was produced by solid-state fermentation on Mandel media under optimized conditions using rice straw as substrate and was partially purified by ammonium sulphate saturation followed by DEAE-cellulose chromatography. Two isoforms of cellobiase, C-I and C-II, which were most kinetically efficient at their optimum pH of 6.0 and temperature of 50 °C were identified after purification,. These isoforms were thermostable at a temperature range of 30–70 °C. Co²⁺, Zn²⁺, and Mn2+ activated whereas, EDTA and Hg²⁺ inhibited the activity of cellobiase. Na⁺, Mg²⁺, K⁺, and Fe²⁺ did not influence the activity of isoforms. The molecular weight of isoforms C-I & C-II was 48 and 44 kDa, respectively. Activation energy (Ea) values for C-I and C-II isoforms were 7.65 and 9.57 KJ/mol and corresponding enthalpy change (∆H) values were 16.27 and 11.49 KJ/mol, respectively. Change in entropy (ΔS) values at 50 °C for C-I and C-II were 0.098 KJ/K/mol and 0.085 KJ/K/mol, respectively. The pK values of ionizing groups in free enzyme and enzyme-substrate complex were between 4.3 and 6.8, indicating the possible precipitation of carboxyl groups of aspartate and glutamate and imidazolium group of histidine in the cellobiase catalyzed the hydrolysis of cellobiose by both isoforms.

5 illus, 5 table, 34 ref

025800   JIN D, TIAN D, GOU Z, LI J (Shenyang Univ of Chemical Technology, China, Email: jindan76@163.com) : New approach to fatigue life prediction of notched specimen under non-proportional loading. Indian J Eng Mater Sci 2018, 25(3), 271-5.

Neuber’s rule and Peterson’s formula are used to calculate the local strain and stress at the notch root based on the fatigue test results of notched specimens of Mod.9Cr-1Mo steel. The critical plane approach, Smith-Watson-Topper (SWT) approach, is used for the fatigue life prediction. It is shown that the prediction results to the notched specimens with smaller notch radius are conservative according to Neuber’s rule but non-conservative when using Peterson’s formula. A new approach to the fatigue strength reduction factor is proposed based on Peterson’s formula by considering the non- proportionality of strain path. With few exceptions, the predictions agree well with the experimental results, and most predictions are in a factor-2 scatter band.

6 illus, 2 tables, 26 ref

025799   AMUTHAKKANNAN P, MANIKANDAN V (Mechanical Engineering Dep, Kalasalingam Univ, Krishnankoil - 626 126, Email: pa_kanna@yahoo.co.in) : Free vibration and dynamic mechanical properties of basalt fiber reinforced polymer composites. Indian J Eng Mater Sci 2018, 25(3), 265-70.

In this study, the free vibration and dynamic mechanical properties of the surface modified basalt fiber reinforced polymer composites have been investigated. The surface modification of fiber has been carried out with 1N solution. Untreated, acid treated and base treated basalt fiber composites were prepared using Hand layup technique. Fourier transform infrared spectroscopes (FTIR) were used for the study of the effect of surface treatment on fibers. The natural frequencies and damping coefficient of the laminated composites have been analyzed using an impact hammer. The result showed better natural frequencies in the untreated basalt fiber composites than composites prepared with treated fiber. Dynamic mechanical analysis (DMA) was also carried out to find the mechanical properties of the composites as a function of temperature, in this analysis also, Untreated basalt fiber composite were found to possesses good storage modulus, loss modulus and damping factor.

6 illus, 1 table, 32 ref

025798   THIRUMALAIKUMARASAMY D, SHANMUGAM K, BALASUBRAMANIAM V (Manufacturing Engineering Dep, Annamalai Univ, Annamalainagar- 608 002, Email: tkumarasamy412@gmail.com) : Influence of spraying time on corrosion behavior of plasma sprayed alumina coatings on AZ31B magnesium alloy under salt fog environment. Indian J Eng Mater Sci 2018, 25(3), 257-64.

Effect of spraying time on the corrosion behaviour of uncoated and atmospheric plasma sprayed alumina (APS) coatings on AZ31B magnesium alloy in NaCl solutions of different spraying times, viz., 1 h, 4.5 h and 8 h has been examined. The corroded area was characterized by an optical microscope and X-ray diffraction. The results showed that the corrosion destruction of uncoated and coated samples was considerably affected by spraying time. The uncoated magnesium and alumina coatings were found to provide a better corrosion resistance in lower spraying time (1 h). However, the coatings and Mg alloy substrate were identified to be highly susceptible to localized damage, and could not provide an effective corrosion protection in higher spraying time (8 h). It was observed that the corrosion resistance of the ceramic coatings and base metal gets deteriorated with increasing the spraying times.

11 illus, 1 table, 30 ref