028563   NAZEMIPOUR A, MANZURI M T (Computer Engineering Dep, Sharif Univ, Tehran, Iran, Email: manzuri@sharif.edu) : Mems gyroscope raw data noise reduction using fading memory filter. J Sci Ind Res 2018, 77(10), 553-8.

Nowadays, MEMS sensors are widely used in systems such as autonomous vehicles, but they still suffer from high stochastic errors such as Angle random walk (ARW) noise, which causes failure in real-signals and produces an error in the position and attitude of mobile systems. So far, many filters are developed to reduce the amount of noise in the output of the MEMS sensors. The computational overhead, the rate of noise reduction, and the phase-delay of the filter are the most important characteristics of choosing a suitable filter. In this paper, a low pass filter based on the alpha-beta filter with a very low computational overhead is proposed to reduce the amount of noise. In order to find the optimal filter gain, the improvement in the positioning is selected as a criterion, which is a tradeoff between the amount of noise reduction and the phase delay of the filtered signal. In this work, the KITTI database is used to evaluate the proposed filter. The results show that the proposed filter reduces the sensor’s noise and improves the positioning of the moving car, significantly.

3 illus, 16 ref

028558   MANISHEKAR R, SIVAKUMAR P, LAKSHMIKANDHAN K N (CSIR-Structural Engineering Research Centre, Chennai - 600 113, Email: rmanisekar17@yahoo.co.in) : Behaviour of distressed RC beams retrofitted by external prestressing using trapezoidal tendons. J Sci Ind Res 2018, 77(9), 520-4.

Rectangular RC beams were tested before and after retrofitting by external Prestressing. RC beams of 150 mm x 275 mm section and 4 m length were subjected to monotonically increasing static two-point load and the cracks were induced to a limit such that the strain in reinforcing steel was around 85 % of the yield strain. Retrofitting by external Prestressing using trapezoidal tendons was done while the member was subjected to superimposed dead weight of a bridge girder, equivalent to 25 % of the ultimate load of the beam. Retrofitted beams were tested by monotonically increasing two-point load. It was observed that ultimate flexural capacity of the beam is increased by 59 %. Around 10 % of loss was observed due to the friction between tendon and deviators. An analytical model is developed and compared with experimental results.

4 illus, 11 ref

028546   EL-DEEB N, EL-ADAWL, SHARAF M, EL ENSHASY H A (Bioprocess Engineering Dep, Teknologi Malaysia Univ, Johor Bahru Johor, Malaysia, Email: henshasy@ibd.utm.my) : Targeting pro-inflammatory cytokines and chemokine as potential novel strategy in adjuvant development for anti- HCV therapy. J Sci Ind Res 2018, 77(9), 510-5.

Hepatitis C virus (HCV) is the main cause of chronic liver disease, cirrhosis and hepatocellular carcinoma (HCC) worldwide. The risk for the development of HCC increases with the severity of liver inflammation and fibrosis. Inflammatory cytokines are critical components of the immune system and influence cellular signaling. In this study, we demonstrated that TNF-α, IL-2 & IL-8 levels were significantly elevated in PBMC– HCV in-vitro model. We tested the hypothesis whether Epicatechin (EC) and/or 6-gingerol (GING) could inhibit such elevation in those cytokines or not. We found that both compound could significantly inhibit the inflammatory cytokines and the use of combined treatment is more effective than single treatment (EC or GING), assuming a possible synergistic effect. In conclusion, the use of anti-inflammatory compounds such as EC and GING as combined treatment may offer a pharmacological approach of targeting TNF-α, Il-2 and IL-8 production, which may provide a potential novel strategy for the development of anti-HCV therapy.

3 illus, 1 table, 26 ref

028556   KUPPUSWAMY C L, RAGHAVENDIRAN T A (Satyabhama Univ, Chennai, Tamil Nadu, Email: clkuppuswamy@gmail.com) : FPGA implementation of carrier disposition PWM for closed loop seven level diode clamped multilevel inverter in speed control of induction motor. J Sci Ind Res 2018, 77(9), 504-9.

This work proposes FPGA implementation of Carrier Disposition PWM for closed loop seven level diode clamped multilevel inverter in speed control of induction motor. VLSI architecture for carrier Disposition have been introduced through which PWM signals are fed to the neutral point seven level diode clamped multilevel using which the speed of the induction motor is controlled. This proposed VLSI architecture makes the power circuit to work better with reduced stresses across the switches and a very low voltage and current total harmonic distortion (THD). The output voltages, currents, torque & speed characteristics for seven level neutral point diode clamped multilevel inverter for AC drive was studied. It has observed the proposed scheme introduces less distortion and harmonics. The results were validated using real time THD meters.

3 illus, 3 tables, 5 ref

028536   AZEEM, BADRUDDIN I A, GHAZALI N N, IDRIS M Y I, ANQI A E, SALMAN AHMED N J, KAMANGAR S, AL-RASHED A A A A (Mechanical Engineering Dep, King Khalid Univ, PO Box 394, Abha 61421, Kingdom of Saudi Arabia, Email: irfan_magami@rediffmail.com) : Effect of size and location of solid on conjugate heat transfer in porous cavity. Indian J Pure Appl Phys 2018, 56(10), 792-801.

The highlight of this article is the influence of a solid over heat transfer characteristics in a square porous cavity. The solid placed inside the porous medium is fraction of the whole domain whose size is varied at 5 different locations of the cavity such as left ( = 0 ), center ( = 0.5), right ( = 1), mid of left and center ( = 0.25), mid of center and right ( = 0.75) wall of cavity. The equations that govern the physical phenomenon have been simplified using popular numerical technique such as finite element method. These simultaneous equations are solved for the solution variables such as temperature and the stream function. The physical domain is divided into smaller segments with the help of triangular elements. The left and right vertical surfaces of cavity are maintained at hot and cold temperature T_h and T_c such that T_h>T_c.

8 illus, 1 table, 47 ref

028577   SIT S K, GUPTA B, SAHOO S (Electronics & Communication Engineering Dep, National Institute of Technology-Jamshedpur, Jharkhand - 831 014, Email: swagatdebmsit@yahoo.co.in) : Dielectric relaxation of benzonitrile and tetramethyl urea with N, methylformamide in C₆H₆ under 9.885 GHz electric field. Indian J Pure Appl Phys 2018, 56(9), 684-95.

Dielectric relaxation of binary (jk) polar mixtures of benzonitrile and tetramethyl urea (TMU) with N,methylformamide (NMF) dissolved in benzene (i) for different weight fractions w_jk’s of polar solutes and mole function x_j’s of NMF at 25, 30, 35 and 40 °C have been studied in terms of relaxation time τ_jk and dipole moment µ_jk from conductivity measurement of solution under 9.885 GHz electric field using Debye Model. Solute-solvent and solute-solute association have been predicted from plot of τ_jk and µ_jk against x_j’s of NMF up to x_j=0.5 and beyond x_j=0.5 to x_j= 1.0, respectively. Estimated τ and µ from both the proposed methods agree with the reported values. Theoretically µ’s have been calculated from bond angles and bond moments of polar groups due to existence of inductive, mesmeric and electromeric effect arising out of microscopic inhomogeneity in them. Molecular dynamics of polar mixtures have been ascertained from Eyring rate equation to establish Debye relaxation mechanism for all systems.

8 illus, 3 tables, 22 ref

028551   JAGADESH P, RAMACHANDRAMURTHY A, MURUGESAN R (Civil Engineering Dep, Coimbatore Institute of Technology, Coimbatore – 641 014, Email: jaga.86@gmail.com) : Overview on properties of sugarcane bagasse ash (SCBA) as pozzolan. Indian J Geo-Mar Sci 2018, 47(10), 1934-45.

This review paper will explore the detailed information on the Sugar Cane Bagasse Ash (SCBA) historical experimental studies, morphological aspects, chemical and physical properties of SCBA along with some fresh and hardened SCBA blended concrete properties. Importance of this overview is to understand the variation of SCBA properties with respect to geological variation, sugarcane cultivation methods and production of ashes methods. Based on the SCBA test properties, the characterization of SCBA at different parts of the world are reviewed and recommendations are suggested that it can be used as pozzolan suitable for marine environment construction.

6 illus, 4 tables, 66 ref

028567   RAGUNATH S, VELMURUGAN C, KANNAN T, THIRUGNANAM S (SVS Coll of Engineering, Coimbatore - 642 109, Email: ragunathsundaram@gmail.com) : Evaluation of tensile, flexural and impact properties on sisal/glass fiber reinforced polymer hybrid composites. Indian J Eng Mater Sci 2018, 25(5), 425-31.

The effective utilization of natural fibers is the main objective of the present research work. But natural fibers alone is not to meet the required strength properties. Hence, one more artificial material is to be added for obtaining required strength. The study undergone on sisal- glass fiber reinforced polymer composites, it is developed by heat compression moulding techniques and their mechanical properties such as tensile, flexural and impact strength are evaluated experimentally under the ASTM standards. The binding properties, internal crack and fiber alignments are examined by morphological test. It is observed that, the tensile strength of sisal/glass fiber composites produce 255.80 MPa. It is approximately same strength (260.10 MPa) of artificial fiber composites. Hence, the use of artificial fibers are minimized by addition of natural fiber which reduces cost of materials and utilization of natural resources. From the SEM test, fiber misalignments are over loading of fibers on composites leads decline in strength. The moisture and wax content of natural fiber may decrease hardness value (23.0 RHN).

4 illus, 9 tables, 32 ref

028535   ABDELKRIM A L, OMAR A (Amar Telidji de Laghouat Univ, Algeria, Email: l.allaoui@lagh-univ.dz) : Corrosion resistance of borided layers obtained on XC38 steel. Indian J Eng Mater Sci 2018, 25(5), 421-4.

Many works were made on the mechanical characterization of borided layers, but studies on the corrosion resistance of these layers are limited. In this work, an evaluation of corrosion resistance of boride coatings on XC38 steel in specific acid and basic solutions (HCl 1N, H₂SO₄ 1N, H₃PO₄ 1N, NaOH 1N, and KOH 1N) was carried out. The formation of iron boride layers (FeB and Fe₂B) on the material surface was obtained in solid medium by pack cementation process. Boriding treatment at 900 °C for 4 h in a powder mixture consisting of 90 % SiC, 5 % B₄C and 5 % NaBF₄ allow to boride layer of about 160 microns thickness. The corrosion behavior was evaluated by weight loss curves after total immersion tests. The results obtained show that in general, corrosion resistance of borided layers is improved compared to that of XC38 steel without Boriding. This improvement varies from one medium to another, and the best improvements were obtained in acidic environments, particularly in sulphuric acid.

9 illus, 10 ref

028584   ZHANG W W, QIN C F, SHI K X, XU R H (Nanchang Hangkong Univ, Nanchang - 330063, China, Email: zdw@ustc.edu) : Fluorescence stress sensing with SrSiAlN₃:Eu²⁺ phosphor-silicone composite. Indian J Eng Mater Sci 2018, 25(5), 417-20.

An experimental piezospectroscopic system was built to study the stress sensing properties of SrSiAlN₃:Eu²⁺ phosphor-silicone composite. A novel technique named barycenter technique was used to analyze the stress-dependent spectra, and accordingly stress sensing functions were obtained. Shape and area of the sample surface on which compressive stress was applied didn’t affect the sensitivity. Stress tests on the experimental setup showed good repeatability for sensing applications. The barycenter technique gave linear stress sensing functions in this research, and finally the determined sensitivity was 0.20 nm/MPa averagely. This sensitivity is one thousand times larger than the piezospectroscopic coefficient of ruby.

3 illus, 1 table, 17 ref

028544   DHANAWADE A, KUMAR S (Mechanical Engineering Dep, S V National Institute of Technology, Surat - 395 007, Email: skbudhwar@med.svnit.ac.in) : Multi-performance optimization of abrasive water jet machining of carbon epoxy composite material. Indian J Eng Mater Sci 2018, 25(5), 406-16.

Carbon epoxy composite material is widely used in naval, aerospace, transportation, structural applications. Traditional machining of carbon epoxy composite is difficult due to improper surface features and kerf geometry, delamination, high tool wear, etc. In the present paper, research work involved in multi-performance optimization of abrasive water jet machining (AWJM) of carbon epoxy composite is described. Taguchi approach and analysis of variance are used to experimentally investigate the influence of process parameters on surface roughness and kerf taper. Four AWJM process parameters namely hydraulic pressure, traverse rate, stand-off distance and abrasive mass flow rate are considered for this study. It is found that two parameters, hydraulic pressure and traverse rate are most significant to control surface roughness and kerf taper. Analysis of scanning electron microscope images of machined surface of work-piece has been carried out to evaluate its microscopic features. The process is optimized for minimum surface roughness and kerf taper using Taguchi based grey relation analysis approach. Confirmation tests are carried out to verify improvement in the response characteristics using optimum set of AWJM process parameters.

12 illus, 9 tables, 16 ref

028547   GHAVIDEL A K, SEYEDZAVVAR M, SHABGARD M (Khazar Univ, Baku, Azerbaijan, Email: mseyedzavvar@khazar.org) : Effect of molybdenum disulfide nanofluid application as coolant in milling process of Al8Si3Cu aluminum alloy. Indian J Eng Mater Sci 2018, 25(5), 397-405.

This paper represents the results of application of molybdenum disulfide nanofluid as coolant in milling process of Al8Si3Cu aluminum alloy. During the experiments, the effects of dry, flood-cooling and MoS₂ nanofluid cooling conditions on cutting temperature and surface roughness of work-piece in milling process were investigated. The cutting speed, feed rate and depth of cut were considered as the input parameters in the range between 80 and 315 mm/min, 80-160 m/min and 0.2 to 0.8 mm, respectively. It was found that the application of molybdenum disulfide nanofluid as a lubricant significantly reduced the surface roughness of work-piece in end milling process. The present of nanoparticles as additives in the coolant was proved to reduce the deterioration of surface quality caused by activated adhesion during cutting operation. This is confirmed by reduction in cutting temperature in milling using MoS₂ nanofluid as compared with dry and flood cooling milling processes. The lowest surface roughness was found to be equal to 0.173 μm at cutting speed of 80 m/min, feed rate of 80 mm/min, and depth of cut of 0.2 mm in end milling process using MoS₂ nanofluid cooling condition. Based on the results, the maximum reduction in surface roughness in end milling process of Al8Si3Cu aluminum alloy with application of MoS₂ nanofluid lubrication in comparison to dry and flood cooling conditions were recorded as 91 and 87.7 %, respectively. In addition, cutting temperatures were reduced in milling process with MoS₂ nanofluid lubrication by 56.8 % and 35.3 % as compared with that of dry and flood cooling conditions, respectively.

11 illus, 2 tables, 34 ref

028575   SHUNMUGESH K, PANNEERSELVAM K (Production Engineering Dep, National Institute of Technology, Tiruchirappalli - 620 015, Email: kps@nitt.edu) : Multi-performance optimization of micro-drilling using Taguchi technique based on membership function. Indian J Eng Mater Sci 2018, 25(5), 383-90.

Carbon fibre reinforced polymers (CFRP) tends to be employed in the manufacture of aerospace industry, construction and costly sports cars, wherever robust and lightweight materials are needed. The present aims to evaluate and optimize the micro-drilling machining process on carbon fibre reinforced polymer composite material in terms of multiple performance characteristics of circularity and cylindricity errors. Micro-drilling tests based on Taguchi L₂₇ orthogonal array are carried out on CFRP laminates under varying cutting conditions of spindle speed, feed rate and drill diameters. The process outcomes are assessed in-terms of circularity and cylindricity errors. The influence and percentage contribution of process parameters are examined by analysis of variance (ANOVA). Taguchi methodology supported by membership function is used for the optimization of the multiple responses transformed to the output of signal-to-noise (S/N) ratio. The scope of the experimental design is to minimize circularity and cylindricity errors simultaneously. Confirmation tests are performed to verify the effectiveness of the proposed hybrid approach.

7 illus, 6 tables, 24 ref

028542   DAS A, SARKAR S, KARANJAI M, SUTRADHAR G (Mechanical Engineering Dep, A P C Ray Polytechnic, Jadavpur, Kolkata - 700 032, Email: dasarunangsu@gmail.com) : An experimental investigation into the role of sintering temperature on the metal removal rate of titanium powder metallurgy products through Taguchi method. Indian J Eng Mater Sci 2018, 25(5), 377-82.

The present work is undertaken to investigate and characterize the machining characteristics (such as metal removal rate, etc) of uni-axially pressed titanium sintered powder metallurgy components. Powder is uni-axially pressed at designated pressure of 840 MPa to form cylindrical samples and the green compacts are sintered at 0.001 mbar for about 4 h with sintering temperature varying from 1350 °C to 1450 °C. Machining experiments are conducted at different parameters in a CNC operated wire-cut EDM. The metal removal rate (MRR) of the machined surface was measured critically. The influence of pulse-on time, pulse-off time and sintering temperature on the MRR of the sintered preforms has been investigated thoroughly. The maximum MRR was achieved at 10 μs of pulse-on time, 11 μs of pulse-off time and sintering temperature of 1450 °C.

9 illus, 8 tables, 12 ref

028543   DESHPANDE Y V, ANDHARE A B, PADOLE P M, SAHU N K (Mechanical Engineering Dep, Visvesvaraya National Institute of Technology, Nagpur - 440 010, Email: deshpandeyv@rknec.edu) : Application of advanced algorithms for enhancement in machining performance of Inconel 718. Indian J Eng Mater Sci 2018, 25(5), 366-76.

Inconel 718 is the most promising nickel-based alloy finding wide usage in engineering applications because of its good mechanical properties. However, this alloy is difficult to machine and results in poor surface quality after machining. Optimization of parameters is essential for improving machining performance of this costly and hard to cut material. The research discusses estimation of optimum parameters using teaching-learning based optimization (TLBO) and compares them to those obtained by genetic algorithm (GA) in turning of Inconel 718. The parameters cutting speed, feed rate and depth of cut are selected as independent variables. The experiments are designed using central composite design of response surface methodology for the modelling of turning process. Surface roughness, tool flank wear and cutting temperature are selected as response parameters for minimization. The adequacy of modified models developed by response surface methodology are tested and then utilized for formulation of multi-objective optimization function. The function is solved by GA and TLBO. After comparing optimization results, the best algorithm is used for confirmation test. Convergence of TLBO algorithm is much faster as compared to GA even though there is very little difference in the optimum values of parameters.

7 illus, 7 tables, 47 ref

028574   SAXENA S, DUTTA B K (CSIR - Advanced Materials Processes Research Institute, Bhopal - 462 026, Email: san_bpl@yahoo.com) : Experimental and numerical evaluation of geometric variation of critical SZW in 20MnMoNi55 steel. Indian J Eng Mater Sci 2018, 25(5), 357-65.

In the present investigation variation of SZWc due to thickness, relative crack size and geometry has been explored in 20MnMoNi55 material using both experimental and numerical techniques. The results showed dependency of critical SZW on thickness and its independency on relative crack size. The critical SZW determined using SE(B) fracture specimen is 17-18 % lower than C(T) and A(T) specimens. The numerical critical SZW methodology predicted the experimental results well. Importance of integral average stress measure parameter while defining minimum thickness criteria is also shown in the results.

12 illus, 2 tables, 31 ref

028554   KHIRATKAR V, AEPURU R, PANDA H S (Materials Engineering Dep, Defence Institute of Advanced Technology, Pune -411 025, Email: hspanda3@gmail.com) : Morphology-controlled ultrafine BaTiO₃-based PVDF-HFP nanocomposite: Synergistic effect on dielectric and electro-mechanical properties. Bull Mater Sci 2018, 41(4), 107.

Perovskite-based flexible nanocomposites were realized by dispersing BaTiO₃ and modified monodisperse BaTiO₃ in PVDF–HFP matrix. BaTiO₃ was modified in situ by the addition of carbon solution, which was prepared electrochemically by using graphite rod. Structural characterization revealed that the decrease in tetragonality due to reduction in particle size of modified BaTiO₃ than unmodified BaTiO₃. The controlled morphology of treated-BaTiO₃ nanoparticles was well dispersed in polymer matrix and exhibited effective dielectric constant. High active surface area of modified BaTiO₃ suggested strong interfacial polarization, reduced dielectric loss and induced relaxation as compared to PVDF–HFP/BT nanocomposite. The experimental dielectric behaviour was fitted with theoretical Maxwell–Garnet model and composites followed up to 20 wt.% filler. The polarization effect was further proven by electric modulus studies of nanocomposites in broad frequency (0.1 Hz–1 MHz) and temperature (−40 to 130 °C). The results suggested that the shift in relaxation peaks towards higher frequencies with increase in filler content in polymer matrix. Further, a flexible-pressure sensing device was fabricated and evaluated for real applications.

12 illus, 36 ref

028580   TÜMKAYA M A, KARAASLAN M, SABAH C (Electrical and Electronics Engineering Dep, Middle East Technical Univ–Northern Cyprus Campus, Turkey, Email: sabah@metu.edu.tr) : Metamaterial-based high efficiency portable sensor application for determining branded and unbranded fuel oil. Bull Mater Sci 2018, 41(4), 91.

In this study, we have developed an efficient metamaterial (MTM)-based portable fuel oil sensor in order to distinguish branded and unbranded fuel-oil samples. Electromagnetic properties of the fuel-oil samples are experimentally obtained and these data are defined in numerical analysis to design and test the performance of MTM sensor. Then, simulated MTM-based sensor structure is fabricated and measured to observe the efficiency and agreement to numerical results. Numerical and experimental studies are conducted in the microwave frequencies of 10–11 GHz. The experiment results are in accordance with the simulation ones. It can be seen from the results that the proposed MTM-based sensor can be implemented into the sensor industry for distinguishing the branded and unbranded fuel oil for several frequency regions.

7 illus, 1 table, 23 ref

028570   SABAH C, MULLA B, ALTAN H, OZYUZER L (Electrical and Electronics Engineering Dep, Middle East Technical Univ, Mersin 10, Turkey, Email: sabah@metu.edu.tr) : Cross-like terahertz metamaterial absorber for sensing applications. Pramana- J Phys 2018, 91(2), 17.

In this work, a new multiband terahertz metamaterial absorber is designed and characterised by numerical simulation method. In addition, the utilisation of the proposed absorber as a sensor is also investigated. The dielectric and thickness sensing characteristics are analysed. The proposed multiband metamaterial absorber has the ability for utilising the terahertz region up to 2 THz. According to the results, it is found that the proposed absorber is capable of sensing unknown materials and material thickness with any of its five absorption bands. The sensitivity of the proposed sensor is 6.57 GHz/unit sensitivity for dielectric sensing and 7.66 GHz/μm for thickness sensing.

8 illus, 2 tables, 31 ref

028578   TAMBA V K, KINGNI S T, KUIATE G F, FOTSIN H B, TALLA P K (Telecommunication and Network Engineering Dep, Dschang Univ, Bandjoun, Cameroon, Email: vkamdoum@gmail.com) : Coexistence of attractors in autonomous Van der Pol-Duffing jerk oscillator: Analysis, chaos control and synchronisation in its fractional-order form. Pramana- J Phys 2018, 91(1), 12.

In this paper, a Van der Pol–Duffing (VdPD) jerk oscillator is designed. The proposed VdPD jerk oscillator is built by converting the autonomous two-dimensional VdPD oscillator to a jerk oscillator. Dynamical behaviours of the proposed VdPD jerk oscillator are investigated analytically, numerically and analogically. The numerical results indicate that the proposed VdPD jerk oscillator displays chaotic oscillations, symmetrical bifurcations and coexisting attractors. The physical existence of the chaotic behaviour found in the proposed VdPD jerk oscillator is verified by using Orcad-PSpice software. A good qualitative agreement is shown between the numerical simulations and the PSpice results. Moreover, the fractional-order form of the proposed VdPD jerk oscillator is studied using stability theorem of fractional-order systems and numerical simulations. It is found that chaos, periodic oscillations and coexistence of attractors exist in the fractional-order form of the proposed jerk oscillator with order less than three. The effect of fractional-order derivative on controlling chaos is illustrated. It is shown that chaos control is achieved in fractional-order form of the proposed VdPD jerk oscillator only for the values of linear controller used. Finally, the problem of drive–response synchronisation of the fractional-order form of the chaotic proposed VdPD jerk oscillators is considered using active control technique.

13 illus, 50 ref

028579   TANG Y, ABDOLMOHAMMADI H R, KHALAF A J M, TIAN Y, KAPITANIAK T (Electrical Engineering Dep, Golpayegan Univ of Technology, Golpayegan, Iran, Email: abdolmohammadi@gut.ac.ir) : Carpet oscillator: A new megastable nonlinear oscillator with infinite islands of self-excited and hidden attractors. Pramana- J Phys 2018, 91(1), 11.

In this paper, we design a new two-dimensional nonlinear oscillator with infinite number of coexisting limit cycles distributed in a plane. One-third of these limit cycles are self-excited attractors while two-third of them are hidden attractors. Modifying this new system to its forced version, we obtain a new nonlinear system with infinite number of coexisting torus attractors and limit cycle attractors.

7 illus, 56 ref

027178   KUMAR T (Processing and Food Engineering Dep, Acharya N.G. Ranga Agricultural Univ, Guntur, Andhra Pradesh, Email: tankeshkumar3@gmail.com) : A review on ohmic heating technology: Principle, applications and scope. Int J Agric Environ Biotechnol 2018, 11(4), 679-87.

Ohmic heating is a novel and alternating thermal processing technology wherein food materials are heated by passing electric current through materials. Ohmic heating has extreme potential for achieving rapid and uniform heating in foods, providing microbiologically safe and high quality foods. Ohmic heating presents a wide range of potential applications including pasteurization, sterilization, aseptic processing, cooking, thawing, blanching, evaporation, extraction, fermentation, and in the military field or long-duration space missions. This review discusses the brief history, basic principle, some process parameters, applicable food products, potential commercial applications and current industrial status of ohmic heating in food industry throughout the world. The review also highlights the scope and work done on ohmic heating in India. The corrosion problems in electrodes and heterogeneous heat generation rate and distribution are interesting area for further research. Ohmic heating is a good comparable with the other ideal technologies like microwave heating, radio-frequency heating and induction heating. More and intensive investigations are required to assess performance and to reduce the overall cost of ohmic heating for viability of commercial application of this technology also in developing countries like India.

72 ref

027177   GUPTA A K, CHAUHAN Y K, MAITY T (Mining Machinery Engineering Dep, Indian Institute of Technology, Dhanbad- 826 004, Email: ankurradikal@gmail.com) : Experimental investigations and comparison of various MPPT techniques for photovoltaic system. Sadhana 2018, 43(8), 132.

This paper deals with Matlab/Simulink and experimental investigations of various maximum power point tracking (MPPT) techniques namely incremental conductance (Inc), perturb and observation (P&O), constant voltage control (CVC) method, and introduction of a novel reference power (Pref) method for extracting the maximum power from the solar photovoltaic (PV) system. The complete system model along with these MPPT methods are developed in Matlab/Simulink and simulation results are obtained during sudden increase in irradiation of 1000 W/m² , and verified experimentally. These MPPT methods are also implemented on Inverse-Sepic converter, which claims to extract maximum power from the PV system. Various experimental observations are taken to access the performance of these MPPT techniques such as settling time of the full load current under sudden exposure of irradiation level of 1000 W/m² , performance during step increase in irradiation level (from 500 W/m² to 1000 W/m² ) and vice versa. Extensive results are taken to compare these methods. The proposed Pref method is found to have lowest settling time to stabilize the load current as 520 ms, whereas, Inc method takes 1.24 s. Further, the efficiency of Inverse-Sepic converter with Pref method achieves the highest efficiency of 95.26 %, whereas, it extracts lowest efficiency on same input as 90.77 % with P&O method. The overall performance of the proposed Pref method is found to be superior as compared to other discussed MPPT methods as verified by experimental results.

13 illus, 5 tables, 29 ref

027176   CHATTERJEE S, MAHAPATRA S S, MONDAL A, ABHISHEK K (Mechanical Engineering Dep, National Institute of Technology, Rourkela- 769 008, Email: mahapatrass2003@gmail.com) : An experimental study on drilling of titanium alloy using CO₂ laser. Sadhana 2018, 43(8), 131.

Laser drilling is a popular method as it eliminates the problem of chatter and vibration due to the absence of physical contact between the tool and workpiece. Tool breakage, a common phenomenon that occurs due to bending of the tool in making of slender holes using conventional drilling, can also be avoided. However, quality of the hole measured in terms of circularity, taper and spatter area is the major concern during laser drilling. The present investigation attempts to find out the optimum parametric setting during drilling of Ti6Al4V using CO₂ laser in order to achieve quality holes. Experiments have been conducted to assess the influence of machining parameters, viz. flushing pressure, laser power and pulse frequency, on the performance characteristics such as taper of kerf, heat-affected zone (HAZ) and spatter area. Taguchi’s L₉ orthogonal array has been used to design the experimental layout as it reduces the experimental cost and time. Analysis of variance has been performed to assess the effect of machining parameter on the performance characteristics. It has been observed that laser power has significant influence on taper of kerf, HAZ and spatter area. Based on desirability approach, the study suggests that all the performance characteristics can be simultaneously optimized at flushing pressure of 40 Pa, laser power of 2250 W and pulse frequency of 1600 Hz. The study also presents a numerical model to simulate the laser drilling process. Since comparison of experimental and numerical model shows a relative error within 10%, adequacy of the numerical model for assessment of quality characteristics of laser drilled holes is justified.

23 illus, 11 tables, 45 ref

027175   TRIVEDI S, PRASAD R (Chemical Engineering and Technology Dep, Indian Institute of Technology (BHU), Varanasi- 221 005, Email: suvernatrivedi@gmail.com) : A four-way catalytic system for control of emissions from diesel engine. Sadhana 2018, 43(8), 130.

The pollution caused by diesel-fuelled vehicles has become a subject of global concern. Presently, various separate technologies such as diesel oxidation catalyst, diesel particulate filter, selective catalytic reduction and ammonia selective catalytic reduction are used to control these pollutants. The four-way catalytic (FWC) system integrates all the separate control systems into a single compact unit. FWC technique using a combination of oxidation–reduction catalysts under various strategies has been investigated to simultaneously remove CO, HC, PM and NOx emitted from diesel engines. An oxidation catalyst (La_0.6K_0.4CoO₃) was prepared by two different methods (sol–gel and co-precipitation). The reduction catalysts: Ag/Al₂O₃ and Cu-ZSM5 were synthesized by impregnation and ion-exchange method, respectively. The FWC was characterized by N₂- sorption, X-ray diffraction, Fourier transform spectroscopy and scanning electron microscopy. The catalytic activities of FWC containing double-layer of catalysts were evaluated in a fixed-bed-tubular-reactor. The highest catalytic activity resulted by the two-layered system of La_0.6K_0.4CoO₃ (sol–gel) + Cu-ZSM5 showing 100 % NO conversion to N₂ at 415 $°$C, maximum-temperature of soot-combustion at 410 $°$C, complete C₃H₈ conversion at 450 $°$C and 100 % CO conversion at 388 $°$C. Maximum NO conversion was maintained up to 427 $°$C; conversion started decreasing with further increase in temperature and 75.4 % conversion remained up to 450 $°$C. The performance of double-layered-catalytic-system was as follows: La_0.6K_0.4CoO₃(sol–gel) + Cu-ZSM5 >La_0.6- K_0.4CoO₃(sol–gel) + Ag/Al₂O₃>La_0.6K_0.4CoO₃(co-ppt) + Ag/Al₂O₃>La0.6K0.4CoO₃(co-ppt) + Cu-ZSM5.

15 illus, 6 tables, 32 ref

027174   THAKUR S K, KUMARI S K, KUMAR Y (Variable Energy Cyclotron Centre, Kolkata- 700 064, Email: thakur@vecc.gov.in) : Design and performance analysis of a crowbar-less high voltage power supply based on PSM technique. Sadhana 2018, 43(8), 129.

A high voltage power supply (HVPS) of rating -40 kV, 5 A is designed and developed based on pulse step modulation (PSM) technique for inductive output tube based RF amplifier. The commercial availability of such power supplies are very limited and that to at a very high cost. In future also, we shall need several PSM based HVPS of various ratings, so in-house development of a high voltage power supply is important to reduce the cost to less than half and also for easy maintenance. The present development is aimed to utilise a modern technique meeting all the important criteria, i.e., solid state based modular construction, crowbar-less design, reliable operation, voltage regulation with higher efficiency, fast response and most importantly easy to service. This paper deals with the design and development of HVPS rated at -40 kV, 5 A by using DSP TMS320F28335 as the main controller along with algorithms for the control system, interlocks and protections, test results, etc.

11 illus, 1 table, 12 ref

027173   REDDY M S, NEERAJA D (Vellore Institute of Technology, Vellore- 632 014, Email: 13phd0169@gmail.com) : Aluminum residue waste for possible utilisation as a material: A review. Sadhana 2018, 43(8), 124.

Recycling and reutilization of industrial waste and by-products are subjects of great importance today in any sector and more so in cement and concrete technology. Aluminium is the most widely used nonferrous metal in the world. During the production of aluminum, a huge amount of waste is produced, known as dross, which is used for recycling and re-extraction of remaining aluminum. The dross is found to be toxic and hazardous waste for the environment and hence recycling or locking up of this waste is very crucial. The dross is mainly composed of oxides and aluminum and in the recycling, salt process is employed to recycle aluminum from the dross. This paper examines various forms of production of aluminum scrap, treatment methods, and typical application of aluminum residue. Brief description on waste management aspects is provided in this paper. The important observations made from the review studies are summarized.

7 illus, 2 tables, 33 ref

027172   BORKAR V S, JAIN A V (Electrical Engineering Dep, Indian Institute of Technology, Mumbai- 400 076, Email: borkar.vs@gmail.com) : Reinforcement learning, Sequential Monte Carlo and the EM algorithm. Sadhana 2018, 43(8), 123.

Using the expression for the unnormalized nonlinear filter for a hidden Markov model, we develop a dynamic-programming-like backward recursion for the filter. This is combined with some ideas from reinforcement learning and a conditional version of importance sampling in order to develop a scheme based on stochastic approximation for estimating the desired conditional expectation. This is then extended to a smoothing problem. Applying these ideas to the EM algorithm, a reinforcement learning scheme is developed for estimating the partially observed log-likelihood function. A stochastic approximation scheme maximizes this function over the unknown parameter. The two procedures are performed on two different time scales, emulating the alternating ‘expectation’ and ‘maximization’ operations of the EM algorithm. We also extend this to a continuous state space problem. Numerical results are presented in support of our schemes.

4 illus, 14 ref

027171   SAMUEL B A, MUKHERJEE R (Indian Institute of Technology, Chennai- 600 036, Email: antonysamuelb@gmail.com) : A study of the unsteady aerodynamics of a wing at high angles of attack using decambering to model separated flow. Sadhana 2018, 43(8), 121.

An Unsteady Vortex Lattice Method is developed and validated. It is coupled with a decambering methodology to account for viscous effects on the aerodynamic coefficients. Two additional methodologies to select a unique solution when multiple solutions arise have been proposed. The transient nature of the aerodynamic loads of a suddenly moving wing at different angles of attack is examined. Sudden jumps are observed in the C_L(t) at post-stall angles of attack. The jumps are followed by the presence of asymmetric solutions, which then decline with time and a change in the solution state. Higher angles of attack see an increasing number of jumps.

18 illus, 14 ref

027170   SANGEETHA M, BHASKAR V, MUTHAMIZHCHELVAN C, MURALI K (Electrical and Computer Engineering Dep, San Francisco State Univ, San Francisco, Email: vcharan@gmail.com) : BER performance analysis of compound chaotic sequence (CCS)-based NR-DCSK system under multipath fading channel. Sadhana 2018, 43(8), 120.

This paper presents the performance analysis of compound chaotic sequence (CCS)-based noisereduction differential chaos shift keying (NR-DCSK) system under multipath Rayleigh fading channel conditions.The special characteristics of chaotic sequences are their deterministic randomness behaviour that adds security andmultipath immunity to the data when used as a carrier in communication systems. In this paper, the chaoticsequences are generated by combining the outputs of chaotic maps, such as logistic map, Chebyshev map, Bernoullishift map, tent map, etc., leading to new complex sequences known as CCSs. This sequence possesses morerandomness, overcomes severe interference levels encountered during transmission and provides higher multipathimmunity compared with those of pseudo-noise (PN) codes. Since NR-DCSK is a spread spectrum technique, itsperformance in wireless multipath fading channels has important considerations. The CCS is used as a carrier inNR-DCSK systems, which leads to improved bit error rate (BER) performance. Comparisons of simulation resultsto theoretical BER expressions of additive white Gaussian noise (AWGN) and Rayleigh fading channels have beencarried out to test the efficiency of the proposed CCS-based NR-DCSK system.

8 illus, 4 tables, 14 ref

027169   JAKIC J, LABOR M, MARTINAC V (Split Univ, Croatia, Email: nina@ktf-split.hr) : The relationship between phase composition and conditions of sintering seawater derived magnesium oxide. Sadhana 2018, 43(8), 119.

This study has focused on the favourable effect of the TiO₂ addition (1, 2 and 5 wt %) on the reduction of B₂O₃ content during activated sintering of magnesium oxide from seawater at temperatures of 1400, 1500 and 1700 $°$C for the duration of 1, 2 and 4 h. A mathematical model of dependence between the B₂O₃ mass fraction in the sintered sample, the temperature of isothermal sintering, the isothermal sintering time and the mass fraction of TiO₂ added have been proposed. Magnesium oxide was obtained from seawater by substoichiometric precipitation, with the addition of 80 % of dolomite lime as the precipitation agent. New phases formed in magnesium oxide samples were examined by the XRD and SEM/EDS analysis. The results indicate that during activated sintering of seawater-derived magnesium oxide with a TiO₂ addition, reactions of formation of Ca₂B₂O₅, CaTiO₃ and Mg2TiO₄ took place simultaneously. The thermodynamics analysis of experimental results, based on the Onsager reciprocity relations (symmetry relations), was applied and phenomenological coefficients were calculated to describe the interference of these three irreversible processes.

4 illus, 4 tables, 16 ref

027168   PARVEEZ M, DHIMAN A, HARMAIN G A (Chemical Engineering Dep, Indian Institute of Technology, Roorkee- 247 667, Email: amitdfch@iitr.ac.in) : Aiding buoyancy driven flow and heat transfer features of converging and diverging trapezoidal cylinders. Sadhana 2018, 43(8), 118.

Numerical computations have been carried out to explore the influence of mixed convection heat transfer from heated trapezoidal geometries of two different configurations namely converging and diverging cylinders in a vertical domain. The recirculation length of the diverging cylinder is found to be more than that of the converging cylinder for all values of Re (5 to 40) considered in this study and this length decreases after introducing buoyancy effect. Drag coefficients decrease with increase in Re for a fixed Ri. However, drag increases for the increasing values of Ri (values considered up to 1). The drag coefficient is found to be the smaller for diverging cylinder than that of converging one. Local Nusselt number shows significant increase as Re and Ri values increase, which results in enhanced heat transfer. Keeping Ri fixed and increasing the value of Re results in the augmentation of heat transfer and is around 15 % at Re = 5 and 23 % at Re = 40 for Ri = 0 for a square cylinder with respect to diverging cylinder. Under the influence of aiding buoyancy, the values of average Nusselt number (Nu) for the diverging cylinder are higher compared to that of converging cylinder. A correlation expressing functional relationship of Nu with Re and Ri has also been generated.

11 illus, 6 tables, 22 ref

027167   ARULMURUGAN B, AGILAN M, JEROME S, ARIVARASU M, MANIKANDAN M, SRIKANTH A, ARIVAZHAGAN N (Vellore Institute of Technology (VIT), Vellore- 632 014, Email: mano.manikandan@gmail.com) : Investigation of metallurgical and mechanical properties of 21st century nickel-based superalloy 686 by electron beam welding technique. Sadhana 2018, 43(8), 117.

Electron Beam Welding (EBW) was performed on the highly corrosion resistance superalloy 686. The present research work investigates the metallurgical and mechanical properties of the weld joint fabricated by Electron Beam Welding technique, and the results are compared with the base metal. Optical and Scanning Electron Microscope (SEM) analysis were carried out to study the structural properties of the weld joint. The fine equiaxed dendritic structure was revealed in the Center Fusion Zone (CFZ). The columnar dendrite was noticed in the Transition Fusion Zone (TFZ). Energy-dispersive X-ray spectroscopy (EDS) analysis results show that segregation of Mo and W were noticed in the sub-grain boundary. X-ray diffraction analysis (XRD) confirmed the presence of Mo and W rich phases in the weldment. Tensile testing was carried out to evaluate the strength and ductility of the weld joint. The result revealed that the weld strength was equal to the base metal strength. The presence of Mo and W-rich intermetallic phase reduced the ductility and toughness of the weld joint compared to base metal. Bend test confirmed the defect-free weld joint that was achieved in the Electron Beam Welding technique. The corrosion rate of base metal and EBW weldment are calculated in the synthetic seawater environment with the help of Potentiodynamic polarization experiment, and corrosion rate is measured with Tafel’s interpolation technique. The corrosion test result shows that the resistance of EBW weldment is lesser than base metal corrosion resistance because of the microsegregation of alloying elements in the interdendritic region.

13 illus, 2 tables, 18 ref

027166   GUPTA V K, THAKKAR J J (Indian Institute of Technology, Kharagpur- 721 302, Email: vishal.vishu.kumar@gmail.com) : A quantitative risk assessment methodology for construction project. Sadhana 2018, 43(7), 116.

It is observed that most of the infrastructure projects fail to meet their cost and time constraints, which will lead to a low return on investment. The paper highlights that the present risk management tools and techniques do not provide an adequate basis for response selection in managing critical risks specific to infrastructure projects. This paper proposes a risk quantification methodology and demonstrates its application for an industrial construction project. A case study is used to present an application of the proposed risk management methodology to help organisations efficiently choose risk response strategy and allocate limited resources. The research adopts an integrated approach to prioritize risks using Group Technique for Order Preference by Similarity to Ideal Solution (GTOPSIS) and to quantify risks in terms of overall project delays using Judgemental Risk Analysis Process (JRAP), and Monte Carlo Simulation (MCS). A comparison between the results of qualitative risk analysis using GTOPSIS and quantitative risk analysis i.e., JRAP and MCS is presented. It is found that JRAP along with MCS could provide some powerful results which could help the management control project risks. The crux of this paper is that the risks are highly dependent on project schedule and the proposed methodology could give a better risk priority list because it considers slackness associated with the project activities. The analysis can help improve the understanding of implications of specific risk factors on project completion time and cost, while it attempts to quantify risks. In turn, this enables the project manager to devise a suitable strategy for risk response and mitigation.

1 illus, 13 tables, 56 ref

027165   MAHIMA S, MOORTHI P V P, BAHURUDEEN A, GOPINATH A (Civil Engineering Dep, Birla Institute of Technology and Science, Pilani, Email: bahurudeen.civil@gmail.com) : Influence of chloride threshold value in service life prediction of reinforced concrete structures. Sadhana 2018, 43(7), 115.

Extensive studies have been reported on the development of service-life prediction of reinforced concrete structures in the last two decades. Service life of a reinforced concrete structure is dependent on the corrosion process, specifically chloride threshold value. Chloride threshold value is a distinctive property and is dependent on several factors such as the supplementary cementitious material used, presence of surface cracks, water to binder ratio, type of steel reinforcement, exposure conditions, measurement methods, etc. Although chloride threshold value is an influential parameter in service-life prediction, a definitive chloride threshold value considering these factors is not reported in the existing literature and standards. Moreover, values adopted in many analytical tools for service life predictions based on the type of steel reinforcement alone are not appropriate and leads to inaccurate calculations. There is a gap in the available literature in understanding the selection of suitable chloride threshold values to be adopted for a specific system. Therefore, it is imperative to study the variation of chloride threshold value with exposure conditions as well as other influencing parameters, to achieve proper service life prediction. In the paper, several influencing parameters on chloride threshold value and its significance on prediction method are comprehensively reviewed. Moreover, suitable recommendations are highlighted for Indian and international standards at the later part of the study.

1 illus, 9 tables, 116 ref

027164   TAFTI M H K, SADEGHZADEH S M (Electrical Engineering Dep, Islamic azad univ, Iran, Email: dr.karimitafti@gmail.com) : Dye sensitized solar cell efficiency improvement using TiO₂/nanodiamond nano composite. Sadhana 2018, 43(7), 113.

This paper aims to demonstrate the efficiency and recombination improvement of Dye-sensitized solar cells (DSSCs) by introducing of a Nanodiamond (NDs)-TiO₂ nano composite. The main challenge in the proposed application is to find the optimal wt.% of ND in TiO₂. The experimental tests were conducted to compare the developed NDs/TiO₂ cell with one of pure TiO₂ nanoparticles prepared in the same conditions. It was observed that short circuit current density, power conversion efficiency, fill factor and electron life time enhanced with increasing ND content. The best performance was obtained with 1 wt.% ND content; with a current density of 12.11 mA/cm² and light-to-electricity conversion efficiency of 4.95 %. The improvement in efficiency of 18.7 % was obtained as the standard DSSC was compared with that of pure TiO₂.

5 illus, 2 tables, 24 ref

027163   DEMIR I,SEVIM O, KALKAN I (Civil Engineering Dep, Kirikkal Univ, Turkey, Email: ozersevim@kku.edu.tr) : Microstructural properties of lithium-added cement mortars subjected to alkali-silica reactions. Sadhana 2018, 43(7), 112.

Little comparative research has been done on the efficiency of lithium additives to reduce the alkali–silica reaction (ASR) expansion. To reduce the ASR effects of reactive aggregate, different mortar bars were obtained by adding lithium additives (Li₂SO₄, LiNO₃, Li ₂CO₃, LiBr and LiF) to the mixing water by the following mass percentages of cement: 0 %, 0.5 %, 1 %, 1.5 %, 2 %, 2.5 % and 3 %. The ASR expansions of the mortar bars at 2, 7 and 14 days were identified according to ASTM C 1260-14. The morphology of the specimens subject to the ASR effect was analysed using a scanning electron microscope, and their chemical composition was analysed by electron dispersion spectroscopy. Among all specimens, the lowest level of 14-day ASR expansion was obtained in mortar bars with 3 % Li₂CO₃ additive.

10 illus, 4 tables, 34 ref

027162   SUBRAMANIAN G H, NAGARJUN C V S, KUMAR K V S, KUMAR B A, SRIKANTH V, SRIKRISHNAN A R (Aerospace Engineering Dep, Amrita Vishwa Vidyapeetham, Coimbatore, Email: ar_srikrishnan@cb.amrita.edu) : Mixing enhancement using chevron nozzle: Studies on free jets and confined jets. Sadhana 2018, 43(7), 109.

This paper reports an experimental study focused on the impact of chevrons (serrations on the trailing edge of the nozzle) on the mixing process of an incompressible jet issuing from a convergent nozzle. The study also explores enhancement of the mixing performance by a novel approach to geometry modification. Profiles of mean velocity were used to characterize the extent of mixing. For a comparative assessment, studies were carried out with a base line circular nozzle, a conventional chevron nozzle and an improvised tabbed chevron nozzle. Flow visualization studies were carried out for jets issuing from chevron nozzles and the results corroborate well with quantitative measurements. The impact of confinement on mixing of jets issuing from chevron nozzles is also studied. The results show that the proposed geometry modification can significantly improve the rate of mixing in the range of Reynolds numbers considered in the study. In confined jets, presence of chevrons was found to accelerate the process of jet break-down.

16 illus, 4 tables, 30 ref

027161   GNANASEKARAN N, BALAJI S (Mechanical Engineering Dep, National Institute of Technology, Surathkal, Email: gnanasekaran@nitk.edu.in) : Inverse approach for estimating boundary properties in a transient fin problem. Sadhana 2018, 43(7), 108.

A solution methodology is proposed for an inverse estimation of boundary conditions from the knowledge of transient temperature data. A forward model based on prevalent time-dependent heat conduction fin equation is solved using a fully implicit finite volume method. First, the inverse model is formulated and accomplished for time-invariant heat flux at the fin base, and later extended to transient heat flux, base temperature and average heat transfer coefficient. Secondly, the Nusselt number is then replaced with Rayleigh number in the forward model to realistically estimate the base temperature, which varies with respect to time, based on in-house transient fin heat transfer experiments. This scenario further corroborates the validation of the proposed inverse approach. The experimental set-up consists of a mild steel 250$\times$150$\times$6 mm³ fin mounted centrally on an aluminium base 250$\times$150$\times$8 mm³ plate. The base is attached to an electrical heater and insulated with glass-wool to prevent heat loss to surroundings. Five calibrated K-type thermocouples are used to measure temperature along the fin. The functional form of the unknown parameters is not known beforehand; sensitivity studies are performed to determine suitability of the estimation and location of sensors for the inverse approach. Conjugate gradient method with adjoint equation is chosen as the inverse technique and the study is performed as a numerical optimization; subsequently, the estimates show satisfactory results.

20 illus, 2 tables, 29 ref

027160   AVCI M, AYDIN O (Mechanical Engineering Dep, Karadeniz Technical Univ, Turkey, Email: mavci@ktu.edu.tr) : Analysis of extended micro-Graetz problem in a microtube. Sadhana 2018, 43(7), 105.

In this numerical study, hydrodynamically developed but thermally developing forced convection in a microtube subjected to a step change in the wall heat flux is analysed using a finite-volume method. The slip velocity and temperature jump conditions at the wall and the axial conduction in the fluid are included in the analysis. The combined effects of the Peclet number and the Knudsen number on the local Nusselt numbers as well as on the wall and bulk temperatures are determined in the continuum and slip flow regimes (0 $\le$ Kn $\le$ 0.1). In the entrance region, large reductions are observed in the Nusselt number with decreasing Peclet number or increasing Knudsen number. The results also show that the thermal length increases with decreasing Peclet number.

7 illus, 31 ref

027159   PANWAR N, CHAUHAN A (Mechanical Engineering Dep, Institute of Engineering and Technology Univ, Chandigarh- 160 014, Email: drchauhan98@gmail.com) : Optimizing the effect of reinforcement, particle size and aging on impact strength for Al 6061-red mud composite using Taguchi technique. Sadhana 2018, 43(7), 101.

Aluminium 6061-red mud composite has been successfully casted by using stir casting. Fairly uniform distribution of red mud reinforcement has been observed by SEM micrographs. The presence of red mud particles inside the matrix has been confirmed by energy dispersive spectroscopy. Impact testing has been done on impact testing machine with a range of 1–300 J (Charpy), 1–175 (Izod) and least count of 0.5 J. Impact strength shows a decreasing trend with increase in percentage reinforcement, aging time and is increased with increase in particle size. ANOVA analysis found that the effect of particle size and aging time are significant but the effect of percentage reinforcement has not been found significant. From the analysis, it can be observed that the particle size influences the impact strength most followed by aging time and percentage reinforcement. Optimum value of impact strength has been predicted by using Taguchi technique and confirmed experimentally by confirmation experiment results.

6 illus, 6 tables, 26 ref

027158   SARAVANAN V, UMESH C K (Mechanical Engineering Dep, B.N.M. Institute of Technology, Bangalore, Email: saravanan.venkatesh@gmail.com) : Numerical comparison for thermo-hydraulic performance of pin fin heat sink with micro channel pin fin heat sink. Sadhana 2018, 43(7), 100.

Cooling of miniature size electronic components has become a challenge for designer in the development of integrated circuits. Micro pin fin heat sink and Micro channel pin fin heat sink are thermal management techniques for effective cooling. The paper presents comparison of fluid flow and heat transfer characteristics for micro pin fin heat sink and micro channel pin fin heat sink with unfinned micro channel heat sink. A three-dimensional heat sink with water as coolant subjected to constant heat flux 10 W/cm², for Reynolds number ranging between 100 and 900 was considered for the study. Extended surfaces of different shapes namely, square and circular with staggered arrangement was considered for both micro pin fin heat sink and micro channel pin fin heat sink. Two non-dimensional parameters namely Nusselt number and thermal performance index were employed to access the performance of heat sink. Results indicate that the microchannel pin fin heat sink has highest nusselt number and friction factor over the whole Reynolds number range. Results also revealed that formation of secondary vortices enhances heat transfer in micro channel heat sink with square pin fin compared to micro channel heat sink with circular pin fin. However, pin fin heat sink has better thermal performance index compared to Micro channel pin fin heat sink and is more preferable when heat dissipation is compared with pressure drop penalty. The Governing equations for fluid and solid domain were solved using FLUENT to study flow and heat transfer characteristics.

21 illus, 4 tables, 29 ref

027157   HUSSAIN K T I, JOTHI T S J (Mechanical Engineering Dep, National Institute of Technology, Kerala- 673 601, Email: tjsjothi@nitc.ac.in) : Vortex ring propagation and interactions studies. Sadhana 2018, 43(7), 99.

This paper experimentally investigates the vortex ring propagation and interactions with thin cylindrical and flat surfaces. Dye-based visualization technique is adopted for the interaction studies. Vortex rings are generated from a circular nozzle of 19 mm diameter with the stroke length ratios (length of the fluid slug to nozzle diameter, L_N/D_N) of 1 to 5, and ejection velocities in the range of 0.05 to 0.2 m/s. Vortex interaction studies are carried out with two different bodies; firstly, with the circular cylinders having the diameters of 0.2, 0.6, 1.5 and 2.5 mm, and secondly with a flat solid surface. Results indicate that the trails in the vortex ring start following at L_N/D_N = 4. The influence of the initial velocity is found to be insignificant on the vortex ring diameter, however, found to depend on stroke length ratio. Vortex-cylinder interaction studies indicated that vortex velocity decreases with increase in cylinder diameter after the interaction. Reconnections of vortex rings are observed in lower cylinder diameter cases. In case of vortex ring interaction with the flat surface, stretching of the vortex core is observed leading to a considerable increase in the vortex ring diameter.

16 illus, 25 ref

027156   KUNDU S, VISWANADHAM B V S (Civil Engineering Dep, Indian Institute of Technology Bombay, Mumbai - 400 076, Email: saptarshikundu123@gmail.com) : Numerical studies on the effectiveness of dynamic compaction in loose granular deposits using shear wave velocity profiling. Indian Geotech J 2018, 48(2), 305-15.

Over the past few decades, Dynamic compaction (DC) has gained popularity as an effective improvement technique for geomaterials in view of its simplicity, low-environmental impact and cost effectiveness. The low carbon footprint associated with this ground remediation method addresses the adverse ecological threats imposed on the environment and society due to unsustainable geotechnical engineering practices encountered in the face of rapid urbanization. In the literature, studies related to numerical modelling of DC are limited, and the existing databases are founded on field trials, past experience and empirical equations. Further, till date, numerical evaluation of improvement in soil strength post DC is restricted primarily to change in relative density of soil samples before and after impact, whereas, in the field, shear wave velocity (V_s) profiling is frequently adopted as a monitoring technique for measuring the degree and depth of improvement. This necessitates a quantitative correlation between the DC design parameters (tamper radius, energy and momentum) and the available shear wave profile data measured in the field for effective design and execution of DC methodology. In order to overcome the above mentioned research gaps, an elasto-plastic soil model with Drucker–Prager failure criteria is incorporated in the present study using FE software ABAQUS. The response of the soil model to large strains developed during multiple tamper drops on dry sand is investigated numerically, and validated with the results of a centrifuge model test, and numerical analyses published in literature. Further, the shear wave velocity of soil samples is assessed numerically based on the value of shear modulus, and subsequent improvement in model soil due to impact (66 % in the present case) is studied to arrive at a better practical application. The results are compared with physically observed field data, and are found to corroborate well. Subsequent parametric studies are carried out by varying the design parameters related to DC, which indicates that the degree and depth of improvement of soil in terms of V_s increases substantially (about 40 %) with an increase in momentum and decreasing tamper radius (about 60 %), whereas, energy imparted has comparatively lesser impact on improvement. A method is eventually proposed with design equations to calculate the improvement after DC in field based on V_s profiling, depending on momentum and radius of tamper. Further, structural requirements coupled with V_s profile data computed in the ground remediated by DC can help in avoiding construction of expensive deep foundations in sites exhibiting poor subsoil profiles, thereby economizing the project. In addition, the above concept ensures sustainability in engineering practices by enabling land-reclamation and utilization of sites exhibiting locally available compressible soils for infrastructure construction and foundation support.

8 illus, 2 tables, 32 ref

027155   LAKSHMIKANTHAN P, SUGHOSH P, BABU G L S (Indian Institute of Science, Bangalore, Email: gls@civil.iisc.ernet.in) : Studies on characterization of mechanically biologically treated waste from Bangalore city. Indian Geotech J 2018, 48(2), 293-304.

The paper presents results of a comprehensive study on characterization of mechanically biologically treated waste generated in Bangalore, India. Physical,biochemical and engineering characteristics of the waste are presented. The methodology to separate the components of consolidation which includes primary, secondary and biodegradation strains is reviewed. A laboratory scalean aerobic bioreactor depicting the behaviour of the waste in a bioreactor landfill was studied for 370 days and the settlement, gas generation and leachate characteristics were monitored. Study on characterization of waste indicates an organic content of 54 % and carbon, nitrogen and hydrogenin the range of 19.28, 1.64 and 11.07 % respectively. Around 20–26 % of settlement and 15 L of landfill gas/kg of dry waste was observed in laboratory scale bioreactor studies. Both laboratory and small scale bioreactor test results indicate that the MSW has high biodegradable content and biomethane potential. It is prone to large settlements and has shear strength parameters comparable to those published in literature. The behaviour of waste under given conditions can be understood from the above studies and the results provide valuable data necessary for designing MSW treatment scheme which includes waste to energy systems and bio reactor landfill with gas and leachate collection systems.

14 illus, 7 tables, 33 ref

027154   VIEIRA C S, PEREIRA P M (Porto Univ, 4200-465 Porto, Portugal, Email: cvieira@fe.up.pt) : Use of mixed construction and demolition recycled materials in geosynthetic reinforced embankments. Indian Geotech J 2018, 48(2), 279-92.

The use of construction and demolition (C&D) recycled materials in the construction industry represents an important step towards a more sustainable future and, simultaneously, represents a new market opportunity to be explored. In the last years, several case studies relating to the application of C&D recycled materials have emerged, mainly, in base and sub-base layers of the roadway infrastructures and in concrete production. This papers deals with the use of fine mixed recycled aggregates as filling material of geosynthetic reinforced embankments.The physical, mechanical and environmental characterization of C&D recycled materials is presented and discussed, as well as, the direct shear behaviour of two C&D materials/geosynthetic interfaces. The C&D recycled material was collected from a Portuguese recycling plant and comes from non-selected C&D wastes. One geogrid and one high strength geotextile were used to assess the interfaces behaviour. The environmental characterization of the C&D recycled material, carried out through laboratory leaching tests, has not shown any environmental concerns. Direct shear test results have revealed that the increase in C&D recycled material moisture content can measurably reduce the interface shear strength. The shear strength of the C&D material/geosynthetic interface has improved with the degree of compaction increase. The coefficients of interaction reached for C&D material/geosynthetic interfaces, akey factor in the design of geosynthetic reinforced structures, compare well with those found in the literature for soil/geosynthetic interfaces.

14 illus, 6 tables, 56 ref

027153   DATTA M, PATEL M, BHOWMIK R, RAMANA G V, SHAHU J T (Civil Engineering Dep, Indian Institute of Technology, New Delhi- 110 016, Email: riyabhowmik89@gmail.com) : Sustainability of landfills in urban areas: Two case studies for enhanced utilization of limited land area. Indian Geotech J 2018, 48(2), 267-78.

Sustainability of landfills is ensured by minimization of waste reaching landfill sites and eventual mining of stabilized waste from landfills (after severalyears) for re-use. Till such a scenario is achieved, expansion of landfill capacities is needed in urban areas. Non availability of additional disposal sites within or near urban areas necessitates enhancement of capacities of landfills on existing limited land areas. This paper presents two case studies on enhancement of capacities of hazardous waste(HW) landfills where 35–50 % more waste has been accommodated on the existing footprint of the landfills.The first case study pertains to design, construction and stability analysis of a new phase of HW landfill, which occupies the existing air space between two completed phases of the HW landfill. The special considerations for the integration of liner and cover components of the new phase with that of the corresponding components of the completed phases to attain complete containment have been highlighted. The second case study pertains to stability analyses conducted to increase utilization of airspace on top of a landfill by increasing its height to more than double of its existing value. This study highlights that interface shear parameters between components of the cover and liner system govern the stability of the landfill slopes, and that use of textured geomembranes is desirable not only in the cover, but also in the basal lining systems.

17 illus, 6 tables, 13 ref

027152   REDDY S B, KRISHNA A M, REDDY K R (Civil Engineering Dep, Madanapalle Institute of Technology and Science, Andhra Pradesh- 517 325, Email: balireddys@mits.ac.in) : Sustainable utilization of scrap tire derived geomaterials for geotechnical applications. Indian Geotech J 2018, 48(2), 251-66.

Use of scrap tire derived (STD) geomaterials in geotechnical engineering applications has received growing interest to prevent creation of wastes and conserve natural resources towards achieving sustainability. STD geomaterials and their mixtures with soils are being used in highway embankments, retaining walls, landfills and other applications as lightweight fill, backfill, compressible inclusion, vibration absorber, and drainage material. The use of STD geomaterials in these applications has been affirmed by characterization of the engineering properties based on laboratory tests and performance assessment based on physical model studies. This paper provides are view of engineering properties of STD geomaterials and their mixtures with soil (predominantly sand) based on published studies. Further, laboratory model and field studies on typical applications of STD geomaterials/mixtures such as retaining walls, foundations, embankments,and landfills are discussed. Overall, STD geomaterial alone or sand mixed with optimal STD content of 30–40 % by weight has been shown to be effective for geoengineering applications.

19 illus, 8 tables, 71 ref

027151   SHIN E C, PARK J J, KANG J K (Civil and Environmental Engineering Dep, Incheon National Univ, Incheon- 22012, Republic of Korea, Email: ecshin@inu.ac.kr) : Stability analysis of underground tunnel for 2nd perimeter highway construction work in Incheon. Indian Geotech J 2018, 48(2), 235-50.

Construction of underground tunnel for highway in the urban area is a challenge to overcome many problems such as subsidence of residential houses and commercial buildings, broken of utilities lines, and vibrating and noise due to rock blasting. This paper presents the analysis of stability of 5.6 km long underground tunnel both partially completed tunnel and planed tunnel section, and the cause of tunnel collapse due to sinkhole. Several methods applied to analyze the stability of tunnel by the monitoring the instrumented data; settlement of ground, ground water level, and lateral and vertical displacement of internal face of tunnel. Soil investigation was also conducted to identify the exact soil layer characteristics and strength of soil and rock, and stratification of soil ground. The rock core was obtained and evaluated for the specimens from the 50 m long horizontal pre-boring process.The numerical analysis was carried out for the stability of tunnel in terms of internal displacement of tunnel, shotcrete bending compressive stress, and rock bolt axial force. GPR survey was also conducted for detection of sinkhole along the route of underground highways.

14 illus, 9 tables, 19 ref

027150   LEE M, BASU D (Civil and Environmental Engineering Dep, Waterloo Univ, Waterloo, ON N2L 3G1, Canada, Email: dipanjan.basu@uwaterloo.ca) : An integrated approach for resilience and sustainability in geotechnical engineering. Indian Geotech J 2018, 48(2), 207-34.

Excessive consumption of energy and natural resources and generation of pollutants are the main reasons why sustainable practices should be strongly advocated in geotechnical engineering. Resilience, on the other hand, isalso important as it improves the ability to cope with uncertain yet extreme events that may occur over the long life cycle of geotechnical infrastructure. There has been increasing recognition that sustainability needs to be incorporated and practiced in geotechnical engineering, but little attention has been paid on incorporating resilience although sustainability and resilience share similar objectives and values. A geotechnical infrastructure may not be truly sustainable if it is not resilient against extreme events and climate change because undesirable consequences caused by the failure of geotechnical infrastructure make the system unsustainable. It is important that the concepts of sustainability and resilience are concurrently considered to ensure that resilience in geotechnical infrastructure is developed while sustainable practices are performed. This paper presents an overview of the key concepts of sustainability and resilience with a particular emphasis on resilience in order to understand the differences and connections between the two. The quantitative and qualitative assessment methods of resilience are also discussed. An integrated assessment framework for the quantification of resilience and sustainability of geotechnical infrastructure is proposed, which is developed based on the driver-pressure-state-impact-response (DPSIR) framework.

17 illus, 13 tables, 96 ref