024680   HAYTA M, ERTOP M H (Food Engineering Dep, Kastamonu Univ, Kastamonu, Turkey, Email: muge_ertop@hotmail.com) : Evaluation of microtextural properties of sourdough wheat bread obtained from optimized formulation using scanning electron microscopy and image analysis during shelf life. J Food Sci Technol 2018, 55(1), 1 - 9.

The aim of this study was to evaluate the microtextural properties of optimized wheat bread formulation consisting sourdough (A) prepared with two different fermentation methods [spontaneous fermentation (F1) versus starter of lactic acid bacteria added fermentation (F2)], instant active dry yeast (B) and wheat bran (C) during shelf life.The optimized levels for F1 were 11.45 g 100 g^-1 for sourdough, 1.10 g 100 g^-1 for dry yeast and 1.58 g 100 g^-1 for wheat bran and for F2 6.99 g 100 g^-1 for sourdough, 1.02 g 100 g^-1 for dry yeast and 38.84 g 100 g^-1 for wheat bran. The addition of sourdough significantly decreased the diameters of starch granules of sourdough breads, and affected shape and surface apparance of starch granules. The retrogradation phenomena during storage was explained with the change of interaction between starch granules and protein matrix. The F1 fermentation method was found to be more effective in terms of bread textural properties examined.

3 illus, 3 tables, 22 ref

024679   KEMAL M, JABASINGH S A, YIMAM A, KUMAR J A (Process Engineering Div, Addis Ababa Univ, Ethiopia, Email: anu3480@gmail.com) : Extraction and characterization of oil from Ethiopian Mangifera indica seed kernels. J Sci Ind Res 2018, 77(2), 131-5.

High population growth demands alternative sources for producing valuable products from waste materials. One such waste material in Ethiopia is mango seed kernel and the oil extracted from the mango seed kernel, have immense application in the cosmetics industry. The main aim of this research is to determine the optimum operating condition for the extraction of oil from the mango seed kernel.

2 illus, 1 table, 17 ref

024678   SINGH T P, SINGH J, SINGH K (Mechanical Engineering Dep, Sant Longowal Institute of Engineering & Technology, Punjab- 148 106, Email: jagtarsliet@gmail.com) : Enhancing the abrasive wear resistance of rotary blade material (AISI 30MnCrB4) by cryogenic treatment. J Sci Ind Res 2018, 77(2), 92-7.

The present study investigates the abrasion wear behaviour of AISI 30MnCrB4 boron steel rotavator blades heat treated under conventional heat treatment (CHT) and deep cryogenic treatment (DCT) processes. For conventional heat treatment, the boron steel blades were oil quenched from 820 ̊C followed by tempering at 200 ̊C. However, the deep cryogenic treatment was carried out at -196 ̊C followed by the controlled heating at 2 ̊C/min to room temperature for a soaking time of 10 hours. The abrasion wear performance of the treated steels was carried out using dry sand rubber wheel (DSRW) test rig under different wear testing conditions using loam sand and sandy loam sand. The experimental results revealed that after deep cryogenic treatment the wear resistance of the boron steel is improved by 26.47 % and 24.07 % for loam sand and sandy loam sand respectively as compared to the conventionally heat treated steel.

3 illus, 1 table, 26 ref

024677   SEHGAL A K, SAXENA M, PANDEY S, MALHOTRA R K (Indian Oil Corporation Ltd, Faridabad, Email: sehgalak@indianoil.in) : Improving performance of compressed natural gas fueled passenger car engine by addition of hydrogen. J Sci Ind Res 2018, 77(1), 61-5.

Hydrogen is a clean fuel that can be used as sole fuel or blends with compressed natural gas (CNG) in the spark ignition engines. Blending of hydrogen in CNG improves the burning velocity and calorific value of CNG. Engine tests were carried out using CNG and optimized fuel blend of 18 % HCNG for comparing the engine performance and emissions behavior. Marginal improvement in engine performance (up to 2 %) and significant reduction in emissions with 18 % HCNG compared to neat CNG. The brake specific fuel consumption was 5 % lesser compared to CNG. Replacement of methane by hydrogen in the 18 % HCNG blend reduced the HC emissions by ~20 % and NOx emissions was increased by ~ 10-20 % compared to CNG. 18 % HCNG decreased the methane emissions up to 25 % compared to CNG. The investigation showed that 18 % HCNG has given better performance and emissions compared to CNG.

3 illus, 3 tables, 16 ref

024676   SAHA B K, MANDAL S K (CSIR-Central Mechanical Engineering Research Institute, Durgapur, Email: subrata.mandal72@gmail.com) : Design of innovative pulse thresher. J Sci Ind Res 2018, 77(1), 50-4.

In manual pulse thresher, input rotary motion is converted into reciprocating motion of beaters. Due to indefinite swing angle of beaters usual four bar linkage cannot be used for this purpose. In this proposed investigation, a novel mechanism has been designed to overcome the problem of indefinite swing angle as is necessary for meaningful operation of manual pulse thresher. Here, Grash of mechanism has been modified to generate the desired kinematics. At first, particular four bar linkage satisfying Grash of’s criteria has been designed considering definite swing angle of beaters, followed by a suitably designed slot has been incorporated into the coupler design to obtain indefinite swing angle. This modified linkage mechanism has been tested successfully to generate variable (may vary even on every cycle) swinging of beaters while taking rotary motion as input.

4 illus, 6 ref

024675   GIRINATH B, MATHEW A, BABU J, THANIKACHALAM J, BOSE S S (Mechanical Engineering Dep, St. Joseph’s of Engineering & Technology Coll, Choondacherry- 686 575, Email: jalumedi.babu@gmail.com) : Improvement of surface finish and reduction of tool wear during hard turning of AISI D3 using magnetorheological damper. J Sci Ind Res 2018, 77(1), 35-40.

Smart materials are the materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli such as stress, temperature, moisture, pH, electric or magnetic fields. Magneto-rheological fluids are smart fluids, which can change their viscosity when a magnetic field is applied. That is, the liquid material will change to a semi-solid under the influence of the magnetic field. Hard turning has gained popularity in machining industries as an alternative to conventional cycle of turning, heat treatment and then finishing for assembly of high wear resistant parts. Vibration developed during the hard turning is the major reason for poor surface finish of the parts produced by this process. The present investigation aims at developing the magneto rheological damper for suppressing the tool vibration and promoting better surface finish. Experiments were conducted on AISI D3 steel of HRC 60 turned with multicoated hard metal inserts with sculptured rake face geometry. This study also presents multivariate loss function for multi criteria optimization of surface finish and tool wear. Experimental results revealed that use of MR damper reduced the surface roughness by three times when compared with that of not using MR damper. Results also revealed that the optimum parameters to improve the surface finish and reduce the tool wear simultaneously are cutting speed 120 m/min and feed rate 0.08 mm/rev.

3 illus, 3 tables, 10 ref

024674   AMARAPU R B, REDDY P V (Engineering Mathematics Dep, ANITS(A), Visakhapatnam, Andhra Pradesh, Email: rameshamarapu.maths@anits.edu.in) : Efficient identity-based parallel key-insulated signature scheme using pairings over elliptic curves. J Sci Ind Res 2018, 77(1), 24 - 8.

Many cryptographic schemes were designed under the assumption that the private keys involved in the system are perfectly secure. If the private key of a signer is exposed then security of the system is totally lost. Key-insulation mechanism minimizes the damage caused by the exposure of private keys in cryptographic schemes. To deal with the key-exposure problem in ID- based schemes, private keys have to be updated at very short intervals; but it will increase the risk of helper key exposure. In order to improve the security and efficiency of key insulation mechanism in ID-based signatures, in this paper, we proposed an ID-based parallel key insulated signature scheme. This scheme uses the bilinear pairings over elliptic curves and is provably secure in the ROM model with the assumption that the CDH problem is intractable. This scheme is strong key- insulated and allows frequent key updates without increasing the risk of helper key exposure and hence improve the security of the system. Also our IDPKIS Scheme reduces the computational, communicational complexity and hence the scheme can be deployed on inexpensive, lightweight and mobile devices.

1 table, 14 ref

024673   CASAS W J P, VIGANICO C E H (Federal do Rio Grande do Sul Univ, CEP 90050-170, Brazil, Email: walter.paucar.casas@ufrgs.br) : Dynamic assessment of freight rail vehicles passing through a jog aperiodic irregularity. J Sci Ind Res 2018, 77(1), 18 - 23.

Many factors may cause accidents with rail vehicles. The main ones are related with the vehicle-load dynamics, rundown tracks and unsafe operations. In order to evaluate the railway vehicle dynamics, a multibody system was implemented to model a railway boxcar with 24 DOFs. Based on the system’s excitation, the vehicle behavior can be evaluated in several operating conditions, and the dynamic system is solved with the Runge-Kutta method for numerical integration. When comparing results from a known model to the ones from the developed program, Dynamic Analysis of Railroad Cars (DARC), a consistent correlation is found. When passing over a jog type aperiodic irregularity, the boxcar of 100 t suffers a vertical acceleration of the car body equivalent to 0.38 g and thus lowers load on the wheels for an instant. Hence, it is possible to conclude that this irregularity is severe. Considering that AAR establishes a minimum value of 10 % of load over the wheel for traffic conditions, the obtained results show there would not be derailment, as the minimum load obtained on the wheel is of 44 % in relation to the static load value.

4 illus, 3 tables, 24 ref

024672   LEE Y H, LIM M H, LEE Y L, LEE Y Y, TAN C S, MOHAMMAD S, MA C K (Teknologi Malaysia Univ, Johor Bahru- 813 10, Malaysia, Email: shahrin@civil.my) : Compressive strength of lightweight foamed concrete with charcoal as a sand replacement. Indian J Engng Mater Sci 2018, 25(1), 98-108.

Foamed concrete, a high performance concrete with lightweight properties and strength-enhancing additive have drawn the attention of researchers towards a sustainable life style. This paper presents a study of the compressive strength of various charcoal-filled lightweight foamed concrete (LFC), where waste materials, water-reducing agent and strength enhancement additives are introduced to the mix design in order to obtain further lightweight concrete. Five series of experimental tests were carried out, where Series 1 tested optimum ratio of silica fume and superplasticizer, Series 2 depicted the design mix of sand replacement with charcoal, Series 3 described the mix for additives, Series 4 illustrated effect of aggregate size for charcoal and different densities, as well as Series 5 was the conventional design mix ratio. The fresh and harden densities have been recorded while the shrinkage of LFC had also been observed during the casting and curing period. From the results, the mixture with silica fume replacing the cement was found to have a lower compressive strength as compared to mixtures with a full portion of cement. The strength reductions ranged between 62 to 80 % for the mix with no superplasticizer and 29 to 82 % for the mix with superplasticizer, which was obtained from the 20 to 50 % of cement replacement with silica fume. Foamed concrete with superplasticizer achieved 66 % of higher compressive strength. However, concrete expansion and spalling were discovered at the later concrete age of Series 5 which degraded the concrete strength. From this study, it was found that charcoal with low specific gravity is a suitable for full sand replacement in foamed concrete prior to the treatment that can lower its alkalinity.

6 illus, 8 tables, 31 ref

024671   KUMAR S, PANNEERSELVAM K (Production Engineering Dep, National Institute of Technology, Tiruchirappalli- 620 015, Email: kps@nitt.edu) : Investigations on dry sliding wear behaviour of nylon-6 and GFR nylon-6 composites using Taguchi technique. Indian J Engng Mater Sci 2018, 25(1), 89-97.

Polymer materials have replaced the metals due to intrinsic lubrication property, superior wear resistance, excellent strength and stiffness to weight ratio, chemical resistance, corrosion resistance and low processing cost. In food and chemical industry polymers are widely used in gear and other sliding machining elements because excellent chemical resistance and good lubrication properties. So In this paper, tribological properties of nylon-6 and glass fiber reinforced (GFR) nylon 6 composites are investigated. Nylon-6 and GFR nylon-6 are injection molded for the fabrication of pins and tested for coefficient of friction and specific wear rate against steel disc under dry condition on a pin-on-disc configuration. The coefficient of friction and specific wear rate are studied at varying glass fiber content (0, 10, 20 and 30 wt %), different sliding velocity (0.5, 1.0, 1.5 and 2.0 m/s), applied load (5, 10, 15 and 20 N), and constant sliding distance (1000 m) under atmospheric condition of temperature and humidity. The disc specimen is made of AISI D2 steel. Process parameters are optimized by taguchi technique. Scanning electron microscope is used further for the study of wear mechanism of worn surface of specimens.

15 illus, 9 tables, 19 ref

024670   LI F-G, YU S-R, CHU H-C, MING-YUAN, LIU E-Y (China Univ of Petroleum, Qingdao- 266 580, China, Email: leego113@163.com) : Heat treatment effect on the damping capacities of Mg₂Si/AZ91D composites. Indian J Engng Mater Sci 2018, 25(1), 85-8.

10 wt % of fly ash cenospheres (FAC) powder fragments with average size of 200 μm were added to the AZ91D Mg alloy slurry to prepare Mg₂Si/AZ91D composites by stirring casting method. Then solution treatment was carried out for the composites. The effects of the solution treatment at 420°C on the morphology of Mg₂Si particles and damping capacities were discussed. The results showed that after the solution treatment, the distribution of Mg₂Si particles in the composite becomes more uniform, and the damping capacities are higher than those of as-cast composite. The results of damping capacity revealed that damping of composites at room temperature is dependent on strain, and can be explained by G-L dislocation theory. At elevated temperatures, interface damping becomes a new contributor to the damping capacity. After the solution treatment, the distribution of Mg₂Si particles in the composite becomes more uniform, and the damping capacities are higher than those of as-cast composite.

4 illus, 3 tables, 9 ref

024669   ARASU I V, CHOCKALINGAM K (Mechanical Engineering Dep, Sethu Institute of Technology, Kariapatti- 626 115, Email: arasu_23@yahoo.com) : Impact of post processing parameter on mechanical properties and surface roughness of selective laser sintered sand mold casting part. Indian J Engng Mater Sci 2018, 25(1), 78-84.

Rapid casting (RC) is an advanced manufacturing technology in additive manufacturing (AM) processes to produce casting parts rapidly. Selective laser sintering (SLS), that is used to produce sacrificial sand mould for casting metal parts in the foundry industry, is regarded as the RC. In this paper the impact of post curing time (PCT), post curing temperature (PCTP), coating (COAT) on the SLS sand mould to the assessment of surface roughness and mechanical properties of the final part produced have been examined. The Taguchi’s L8 orthogonal array is selected for the experiments and findings are evaluated using analysis of variance (ANOVA) .The experimental results show that the parameter PCTP has a significant effect on the mechanical properties and COAT on surface roughness. Surprisingly, the uncoated mould casting parts exhibit good surface finish than coated mould parts, due to the smaller diameter holes caused an uneven coating on the mould. The microstructure and bonding of the sintered moulds are observed by SEM analysis. Findings also suggest that machining will be always required to decrease the surface roughness.

10 illus, 8 tables, 21 ref

024668   CHANDRAMOHAN P, BHERO S, OBADELE B A, OLUBAMBI P A, RAVISANKAR B (Metallurgy Dep, Johannesburg Univ, South Africa- 2028, Email: pcmohu@yahoo.co.in) : Effect of built orientation on direct metal laser sintering of Ti-6Al-4V. Indian J Eng Mater Sci 2018, 25(1), 69-77.

The use of direct metal laser sintering for fabrication of three-dimensional engineering parts is fast gaining momentum in the engineering industries. This process consolidates metallic powders by using a laser source. In this study, the effect of built direction (horizontal and vertical) on the microstructure, mechanical properties and corrosion resistance of Ti-6Al-4V alloy printed using direct metal laser sintering (DMLS) technology was investigated. Results show that microstructure of Ti-6Al-4V surface have few pores. The melt pool of vertically built parts revealed the presence of fine cellular-dendritic martensite. Microhardness of vertical built specimens was relatively higher than the horizontal built specimens which could be due to the presence of vanadium carbide. Fractography analysis revealed that horizontal built specimens displayed higher ductility than the vertical built. For horizontal built sample, the corrosion current densities in 3.5 % NaCl and 1 M HCl solutions are significantly lower when compared with that of 1 M H₂SO₄, which might be because of stable oxide layer formation. Generally, horizontal build parts yield relatively better mechanical properties and corrosion resistance supported by ideal microstructure. In case of vertical built-up, it is better to limit to a maximum height of 40 mm for the set parameters.

11 illus, 1 table, 22 ref

024667   ISLAM M M, KIM H, KO T J (Mechanical and Automotive Engineering Dep, Andong National Univ, Gyeongbuk- 760 749, South korea, Email: hckim@anu.ac.kr) : Simulation of surface patterns imprinted by wheel grinding which dressed by rounded tools. Indian J Eng Mater Sci 2018, 25(1), 59-68.

Surfaces having more precise pattern are effective for lubrication, friction or drag, being designed by engineers and incorporated into the components specification. Therefore, it is very important to develop such precise surface patterns in a repeatable and economically viable way. The aim of this research work is to develop rounded groove surface pattern model by grinding with the grooved wheel based on dressing. In order to grooving of grinding wheel, a rounded tip dresser is used instead of sharp tip dresser. The developed grooved wheel geometry model can be integrated with a grinding process model for simulating rounded groove surface patterns. A computer based simulation program is developed using Matlab according to proposed mathematical model to display 3D geometry of the patterned surface. The simulation results of resulting surface pattern with rounded groove can be realized by interactively inputting parameters in to the developed software. An experiment has been carried out for the verification of the simulation results and it is found that the simulation results agree well with the experiment. The simulation results could be used to predict the rounded groove surface patterns by the given grinding parameters.

17 illus, 3 tables, 36 ref

024666   RASHEED M S, ABIDI M H, AL-AHMARI A M (Abu Dhabi Vocational Education Training Institute, Abu Dhabi, UAE, Email: mabidi@ksu.edu.sa) : Effect of electrode material in micro-electrical discharge machining of micro-holes drilled in shape memory alloys. Indian J Eng Mater Sci 2018, 25(1), 42-58.

Machining of advanced engineering materials is a major problem faced by the industry. Electrical discharge machining (EDM) provides a solution to this problem, and it is utilized for machining of such electrically conductive materials. Micro- EDM (μEDM) technology is used to drill micro-holes in various components in the aerospace industry and automotive industry. Such holes need to have good surface finish and good dimensional accuracy. It is difficult to maintain a high accuracy and good surface finish at such a minute level. Therefore, this work tries to solve this issue by conducting an experimental study in which micro-holes are drilled in the Ni-Ti shape memory alloy (SMA) and stainless steel (SS) using μEDM. The effect of the electrode material on micro-holes is investigated. Surface characteristics and dimensional accuracy of the machined micro-holes are evaluated based on micrographs obtained by scanning electron microscopy (SEM). The results reveal that the material removal rate (MRR), surface finish, and dimensional accuracy are significantly affected by the machining parameters (i.e., discharge energy (pulse voltage and capacitance) in R–C circuit during machining), tool electrode material, and type of hole to be drilled (through hole or blind hole). In addition, fine surface finish is also dependent on the electrical and thermal properties of the electrode material.

18 illus, 4 tables, 43 ref

024665   KUMAR P, SINGH G, JAIN V, GUPTA D (Shivalik Coll of Engineering, Dehradun- 248 197, Email: gurmeet.singh@thapar.edu) : Optimization of process parameters for improving drilling quality and machining performance of abrasive assisted drilling on AISI D2 steel. Indian J Eng Mater Sci 2018, 25(1), 33-41.

This research is concerned with optimization of roughness and material removal rate, as a result of AISI D2 steel drilling with abrasive assisted high speed steel drill. Experimentation include drilling of AISI D2 steel with supply of Sic and Al₂O₃ abrasive slurry having mesh size 800, 1200 and 1500 with slurry concentration of 20, 25, and 35 %. The drilling parameters namely orthogonal types array of abrasive, for surface abrasive roughness mesh and size, material spindle removal speed, rate. slurry Analysis concentration of variance and feed is employed rate were to optimized find the percentage using L18 contributions of each control parameters. The results show that the type of abrasives and abrasive mesh size are the most significant factors which affect the roughness of drilled hole walls. The material removal rate affects significantly by feed rate and type of abrasive. The performance in the conventional drilling can be effectively improved by using hybrid drilling.

5 illus, 12 tables, 27 ref

024664   GUNEN A, KANCA E, DEMIR M, CAVDAR F, MISTIKOGLU S, CAM G (Materials Engineering Dep, Iskenderun Technical Univ, Hatay, Turkey, Email: aligunen2013@gmail.com) : Microstructural and mechanical properties of friction stir welded pure lead. Indian J Eng Mater Sci 2018, 25(1), 26-32.

The present study focuses on the applicability of friction stir welding to pure Pb plates. The joint performances are evaluated by optical microscopy, microhardness measurements, notch impact tests and three point bending tests. The effects of the tool rotational speed (1500, 2000 and 2500 rev/min) and welding speed (72, 100 and 125 mm/min) on the joint performance are determined. The results indicate that the welded joints exhibit similar or higher mechanical properties than those of the base material. Optimal joint performance was achieved with a rotational speed of 1500 rev/min and welding speed of 100 mm/min.

5 illus, 2 tables, 53 ref

024663   DAS P K, KUMAR N, CHAKRABORTI P (Mechanical Engineering Dep, National Institute of Technology, Agartala- 799 046, Email: pankaj_642004@yahoo.co.in) : Loading effect on friction behavior of ordered/disordered graphite in ambient and inert condition. Indian J Eng Mater Sci 2018, 25(1), 19 - 25.

Load dependent friction behavior of structurally ordered and disordered graphite is measured in ambient and nitrogen gas atmosphere. Friction coefficient is significantly less in graphite in order as compared to disorder in ambient atmosphere. This behavior is attributed to structural defects in graphite lattice. However, under nitrogen gas, friction coefficient graphite is significantly high irrespective of structural order or disorder of graphite. This typical behavior is mainly attributed by chemical reactivity of graphite surface which is high in nitrogen gas and not much influenced by structural ordering/disordering. In both types of graphite, steep increase in friction coefficient is observed at high load. This is explained by reasonable increase in contact area and followed by the Johnson−Kendall−Roberts (JKR) model.

5 illus, 36 ref

024662   SUBRAMMANIAN A, SENTHIIL P V, JABARAJ D B, JAYAPRAKASH J (St Peters Univ, Chennai- 600 054, Email: prakash221271@gmail.com) : Effect of process parameters on the mechanical performance of resistance spot welded joints of AISI 409M ferritic stainless steel. Indian J Eng Mater Sci 2018, 25(1), 11 - 8.

In this study, the effect of process parameters on mechanical performance of the resistance spot welded joints of AISI 409M ferritic stainless steel sheets is investigated. Mechanical performance of the spot weld is evaluated in terms of output quality characteristics, such as load carrying capacity and energy absorption capacity. Important process variables, such as current, time, electrode force and holding time were varied separately and corresponding output parameters, which decide the mechanical performance of the spot welded joint have been analysed. Weld nugget geometrical parameters such as nugget size and surface indentation have also been analysed with respect to various process variables. It has been found that peak load and energy absorption capacity are in direct relationship with welding current as well as welding time, in expulsion free welds. Surface indentation increases with increase in current and welding time. It has also been observed that increasing electrode force results in slight reduction of both tensile shear strength and energy absorption capacity. The effect of holding time on mechanical performance of the resistance spot welded joint is found to be almost insignificant. Regression-based relations are developed to correlate the mechanical performance of the spot welds with nugget size.

13 illus, 1 table, 25 ref

024661   GURAU C, GURAU G, SAMPATH V (Galati Univ, Galati, Romania, Email: gheorghe.gurau@ugal.ro) : Structural study and phase transformation of Cu-Al-Ni shape memory alloy produced by severe plastic deformation. Indian J Eng Mater Sci 2018, 25(1), 5 - 10.

Martensitic transformation and mechanical behavior are investigated on extremely brittle Cu-13Al-4Ni shape memory alloy subjected to severe plastic deformation (SPD) by high speed high pressure torsion (HSHPT). The HSHPT process involves high pressure coupled with torsional deformation of the alloy, at which large rotation speed (1795 rpm) of the upper punch generates heat by friction. The experiments are carried out in a Bridgman cell right from room temperature. The disc-shaped Cu-Al-Ni samples produced by this technique have diameter between 20 and 29 mm and thickness until 0.16 mm, depending on the extent of deformation. Microstructural analyses are performed on the alloy that had undergone processing by optical, scanning electron as well as transmission electron microscopy. The microstructural investigations show that increasing the degree of deformation leads to gradual grain refinement. The microstructural changes are correlated with the Vickers hardness of the alloy. The alloy processed by HSHPT shows reversible martensitic transformation without the necessity for post-deformation annealing and phase transformation stability after 10 thermal cycles, too.

6 illus, 1 table, 31 ref

024660   ONEY O (Mining Engineering Dep, Eylul Campus, Usak-64200, Turkey, Email: ozcan.oney@usak.edu.tr) : Optimization of operating parameters of graphite flotation circuit using box-behnken design. Indian J Chem Technol 2018, 25(2), 170-8.

Flotation is a continuous process, therefore conventional tree analysis tests do not fit to determine the quantity and quality of the products. Hence, it is necessary to incorporate flotation circuits. The present study presents optimization of three stage graphite flotation circuits. Response Surface Methodology (RSM) is used to determine the optimum flotation conditions. In addition, the relationship between process variables (diesel oil dosage, methyl isobutyl carbinol dosage and sodium silicate dosage) and the responses (weight, carbon content and recovery) has been investigated. Analysis of variance has been performed to check the suitability and significance of the quadratic models. The results are found to be compatible withproposed models (R² ˃0.97) which lead to obtain 13.48 weight % of clean graphite, 78.91 % carbon content and 54.55 % carbon recovery fromthree-stage flotation circuit.

4 illus, 7 tables, 23 ref

024659   JOHNSON S C, THIRUGNANAM G S (Excel Engineering Coll, Tamil Nadu- 637 303, Email: glorylydiajohn@gmail.com) : Innovative methods for improving performance of transmission line tower foundations against corrosion in marine environment. Indian J Geo-Mar Sci 2018, 47(01), 200-3.

In the study a few innovative methods for rehabilitation of transmission line tower foundations based on laboratory investigations have been presented. Protective methods like O-ring provision in the stub angle concrete interface, various levels of protective methods including nano penetrant coatings to combat the crevice corrosion, has been suggested for field applications in marine environment.

3 illus, 5 ref

024658   MOHAMED A, KCHAOU H, ABID M S, DRISS Z (Sfax Univ, Sfax-3038, Tunisia, Email: aymenenis@gmail.com) : Impact of stern design on hydrodynamic drag of AUV's hull. Indian J Geo-Mar Sci 2018, 47(01), 89-95.

Identification of hydrodynamic parameters of the bare hull model is a paramount step in AUV design. CFD investigation using ANSYS Fluent basing on K-ω SST turbulence model and a different mesh density is established for the velocity ranging from 0.4 m/s to 1.4 m/s. The numerical calculation of the drag coefficient with y+=√ 2 are revealed in good agreement with experimental data from towing tank tests of Jagadeesh et al despite the low Reynolds regime. Thus, the comparison between different afterbody models shows the significant effect of the stern design on the hydrodynamic drag of the vehicle and the onset of flow separation around the stern part.

12 illus, 1 table, 12 ref

024657   LEE T-H, NGUYEN D-D (Civil Engineering Dep, Vinh Univ, Vinh 460 000, Vietnam, Email: duan468@gmail.com) : Seismic vulnerability assessment of a continuous steel box girder bridge considering influence of LRB properties. Sadhana 2018, 43(1), 14.

Bridges are one of the most crucial facilities of transportation networks. Therefore, evaluation of the seismic vulnerability of bridge structures is perpetually regarded topic for researchers. In this study, we developed seismic fragility curves for a continuous steel box girder bridge considering the effect of different levels of mechanical properties of lead rubber bearing (LRB) devices including initial stiffness and yield strength on the seismic performance of such structure. A powerful framework for an earthquake engineering simulation, OpenSees, is used to perform nonlinear analyses of the bridge model. In order to construct fragility curves for this structure, a set of 20 ground acceleration records is adopted and various scales of the peak ground acceleration (PGA) from 0.1 to 1.6 g are considered. Besides, a series of damage state of the bridgeis defined based on a damage index, which is expressed in terms of the column displacement ductility ratio. Fragility analyses result reveals that reducing the initial stiffness of LRBs reduces the seismic vulnerability of bridge piers and vice versa. Meanwhile, the changes of the yield strength of LRBs have trivially effected on the seismic behaviour of the bridge piers. On the other hand, the short pier has performed more susceptibly than those of the high pier in both seismically-isolated and non-isolated bridge cases. Lastly, the results in this research also indicate that the bridge structures equipped with seismic isolation devices (e.g. LRBs) significantly mitigated the damages due to earthquakes.

18 illus, 8 tables, 21 ref

024656   ANOOP K V, SINGH O P (Mechanical Engineering Dep, Indian Institute of Technology, Kanpur-208 016, Email: singhompal083@gmail.com) : The build-up and characterization of nuclear burn-up wave in a fast neutron multiplying medium. Sadhana 2018, 43(1), 11.

A study has been carried out on the build-up and characterization of nuclear burn-up wave in fast neutron multiplying media. The focus of the study is more on the transient part of the burn-up wave though the steady state is also studied. The characteristics of the transient part are expressed in terms of new parameters, i.e., Transient Length (TL) and Transient Time (TT) elapsed in establishing the asymptotic burn-up wave. The TT and TL are defined, respectively, as the time and length needed to establish 95 % and 99 % of the asymptotic neutron flux propagating in the media. From these parameters, the transient wave velocity is determined. The characteristics of asymptotic part of the wave are determined in terms of wave velocity, Full Width at Half Maximum (FWHM) and Full Width at 10 % Maximum (FW10M) of neutron flux distribution in the space. A parametric study is also carried out to investigate the sensitivity of these parameters to some of the physical parameters of the ignition zone and the breeder zone of the reactor. The characterization parameters would be very meaningful to understand the transient characteristics of the self-sustaining nuclear burn-up wave and in evaluating the quality of the wave by the researchers working in the field of nuclear burn-up wave build-up and propagation.

9 illus, 4 tables, 26 ref

024655   RAHMAN N I A, DAWAL S Z M, YUSOOF N, KAMIL N S M (Mechanical Engineering Dep, Malaya Univ, Kuala Lumpur-50603, Malaysia, Email: izzahrahman@um.edu.my) : Anthropometric measurements among four Asian countries in designing sitting and standing workstations. Sadhana 2018, 43(1), 10.

An anthropometric database for sitting and standing dimensions for Malaysian operators was developed based on the measurements from 146 male and 168 female participants (18–45 years old). The anthropometric data were subsequently compared to those from three selected Asian countries, focussing on the sitting and standing posture dimensions. Thirty-six anthropometric dimensions were selected for comparison based on common availability among the four countries. The results indicated that the Indonesians were the tallest (male: 172 cm, female: 159 cm) among the four countries, whereas the Filipinos were the shortest for both male and female (male: 167 cm, female: 153.9 cm). Filipinos and Malaysian data were almost similar and appear to have the smallest values for eye height (male: 155 cm, female: 143 cm) and elbow height (male: 104 cm, female: 96 cm). The knowledge of variations in the population is useful in designing sound workstations and facilities for the betterment of the industrial environment.

5 illus, 4 tables, 26 ref

024654   PRIYANKA C, NITHYA V, BHASKAR V (Electrical and Communication Engineering Dep, San Francisco State Univ, CA 94132, USA, Email: priyankachandrashekar391@gmail.com) : k?l fading channels: a finite state Markov modelling approach. Sadhana 2018, 43(1), 7.

Finite state Markov channel (FSMC) is the automatic choice for accurate modelling of slow fading channels with memory. FSMC model for a k–l fading channel is investigated in this paper. Small-scale variations of the fading signal under Line-Of-Sight conditions are represented by k–l fading distributions. Here, FSMC is constructed by partitioning the fading amplitude into several regions. Each region corresponds to a particular state in the Markov model. The transition among these channel states characterizes the physical fading process. Performance measures such as steady-state probability, state-transition probability, level crossing rate and state-time duration corresponding to the k–l fading channel are derived, plotted and analysed. Finally, numerical results prove that FSMC modelling provides an effective way to reflect the nature of the k–l fading channel.

4 illus, 17 ref

024653   TATTE Y, AWARE M (Electrical Engineering Dep, Visvesvaraya National Institute of Technology, Nagpur- 440 010, Email: ytatte@gmail.com) : Torque ripple reduction in direct torque controlled five-phase induction motor using modified five-level torque comparator. Sadhana 2018, 43(1), 6.

The five-phase induction motor inherently has the minimal torque ripple. However, when it is controlled by direct torque control (DTC) technique, the torque ripple increases due to the presence of a hysteresis torque comparator. The classical five-level torque comparator is presented in the previous literatures to control the torque ripple. However, this comparator has the drawback of wrong selection of zero voltage vectors inside the inner band on the positive side of the comparator, which enables the torque ripple to increase and dc-link utilization to decrease. In this paper, in order to reduce the torque ripple and to increase the dc-link utilization, a modified five-level torque comparator is proposed, which selects either medium or small voltage vectors instead of zero voltage vectors inside the inner band on the positive side of the comparator. In addition to torque ripple reduction and improvement in dc-link utilization, the proposed comparator significantly improves the quality of phase current. All the available 32 voltage vectors are selected through the proposed five-level torque comparator based on the location of x–y stator flux in order to eliminate the x–y stator flux so as to obtain reduced distortion in the phase current. By employing all the available voltage vectors, the freedom of utilization of all voltage vectors in the five-phase induction motor DTC drive is availed. The proposed five-level torque comparator is compared to its classical five-level counterpart through simulation and experimental results in order to validate the proposed DTC strategy.

15 illus, 4 tables, 14 ref

024652   FRANCIS B, VISWANATH S, ARIGOVINDAN M (Electrical Engineering Dep, Indian Institute of Science, Bangalore 560012, Email: francisbibingeorge@gmail.com) : Scattered data approximation by regular grid weighted smoothing. Sadhana 2018, 43(1), 5.

Scattered data approximation refers to the computation of a multi-dimensional function from measurements obtained from scattered spatial locations. For this problem, the class of methods that adopt a roughness minimization are the best performing ones. These methods are called variational methods and they are capable of handling contrasting levels of sample density. These methods express the required solution as a continuous model containing a weighted sum of thin-plate spline or radial basis functions with centres aligned to the measurement locations, and the weights are specified by a linear system of equations. The main hurdle in this type of method is that the linear system is ill-conditioned. Further, getting the weights that are parameters of the continuous model representing the solution is only a part of the effort. Getting a regular grid image requires resampling of the continuous model, which is typically expensive. We develop a computationally efficient and numerically stable method based on roughness minimization. The method leads to an algorithm that uses standard regular grid array operations only, which makes it attractive for parallelization. We demonstrate experimentally that we get these computational advantages only with a little compromise in performance when compared with thin-plate spline methods.

13 illus, 2 tables, 38 ref

024651   KRAJANGSOD S, CHOTIKAMAS S, TAWAI A, SRIARIYANUN M (The Sirindhorn International Thai-German Graduate School of Engineerin, Bangkok -10800, Thailand, Email: macintous@gmail.com) : Measurement and thermodynamic modelling of Erythritol solubility in aqueous solvents. Oriental J Chem 2018, 34(1), 265-75.

Purification process of erythritol in industrial production are currently composed of multiple steps. To improve the purification efficiency and to operate the working condition precisely, the solubility property of erythritol should be monitored. In this study, the erythritol solubilities in aqueous solvents including methanol, ethanol and 2-propanol were experimentally measured by using the gravimetric method within the temperature range of 273.15 K to 283.15.15 K (with 2 K interval) and 283.15 K to 323.15 K (with 10 K interval). The experimental results showed that erythritol solubility increased due to the increase of temperature but decrease of mass fraction of organic solvent. The solubility was also depended on polarities of solvents. The lowest solubility was obtained when using aqueous ethanol. To generate solubility model of erythritol, Apelblate equation, Buchowski-Ksiazaczak λ h equation and Van't Hoff model were applied to explain correlation and behavior of erythritol solubility. Based on statistical analysis, Apelblate equation obtained the best correlation to the experimental data compared to Buchowski-Ksiazaczak λ h equation and Van't Hoff model. The solubility model with the estimated parameters could be further applied for optimizing purification processes of erythritol in industries.

4 illus, 6 tables, 16 ref

024650   SORGER V J, AMIN R, KHURGIN J B, MA Z, DALIR H, KHAN S (Electrical and Computer Engineering Dep, George Washington Univ, DC -20052, United States of America, Email: sorger@gwu.edu) : Scaling vectors of attoJoule per bit modulators. J Optics 2018, 20(1), 14012.

Electro-optic modulation performs the conversion between the electrical and optical domain with applications in data communication for optical interconnects, but also for novel optical computing algorithms such as providing nonlinearity at the output stage of optical perceptrons in neuromorphic analog optical computing. While resembling an optical transistor, the weak light– matter-interaction makes modulators 105 times larger compared to their electronic counterparts. Since the clock frequency for photonics on-chip has a power-overhead sweet-spot around tens of GHz, ultrafast modulation may only be required in long-distance communication, not for short on-chip links. Hence, the search is open for power-efficient on-chip modulators beyond the solutions offered by foundries to date. Here, we show scaling vectors towards atto-Joule per bit efficient modulators on-chip as well as some experimental demonstrations of novel plasmonic modulators with sub-fJ/bit efficiencies. Our parametric study of placing different actively modulated materials into plasmonic versus photonic optical modes shows that 2D materials overcompensate their miniscule modal overlap by their unity-high index change. Furthermore, we reveal that the metal used in plasmonic-based modulators not only serves as an electrical contact, but also enables low electrical series resistances leading to near-ideal capacitors. We then discuss the first experimental demonstration of a photon-plasmon-hybrid graphene-based electro-absorption modulator on silicon. The device shows a sub-1 V steep switching enabled by near-ideal electrostatics delivering a high 0.05 dB V⁻¹ μm⁻¹ performance requiring only 110 aJ/ bit. Improving on this demonstration, we discuss a plasmonic slot-based graphene modulator design, where the polarization of the plasmonic mode aligns with graphene’s in-plane dimension; where a push–pull dual-gating scheme enables 2 dB V⁻¹ μm⁻¹ efficient modulation allowing the device to be just 770 nm short for 3 dB small signal modulation. Lastly, comparing the switching energy of transistors to modulators shows that modulators based on emerging materials and plasmonic-silicon hybrid integration perform on-par relative to their electronic counter parts. This in turn allows for a device-enabled two orders-of-magnitude improvement of electrical-optical co-integrated network-on-chips over electronic-only architectures. The latter opens technological opportunities in cognitive computing, dynamic data-driven applications systems, and optical analog computer engines including neuromorphic photonic computing.

10 illus, 66 ref

024649   DENG K, SERMENT-MORENO V, WELTI-CHANES J, PAREDES-SABJA D, FUENTES C, WU X, TORRES J A (Food Science and Technology Dep, Oregon State Univ, Oregon- 97331, USA, Email: o.vichko.te@gmail.com) : Inactivation model and risk-analysis design for apple juice processing by high-pressure CO₂. J Food Sci Technol 2018, 55(1), 258-64.

The article describes some probiotic properties of fermented product made of natural association of Tibetan kefir grains cultivated in Ukrainian household (UTKG); also, the effect of UTKG microbiota on the growth of pathogenic microbiota and sensitivity to antibiotics was studied. It was found that the test-cultures of oppurtunistic pathogens (Staphylococcus aureus, Bacillus mesentericus, and Mycobacterium luteum) were sensitive; bacteriostatic zone of the test-culture ranged from 21 to 25 mm, and highly sensitive (Proteus vulgaris and Aspergillus niger) bacteriostatic zone exceeded 25 mm to probiotic bacteria of fermented product. UTKG microbiota is also moderately sensitive to multiple antibiotics that allows defining the obtained fermented milk product as functional with therapeutic properties. During the study of the influence of different NaCl and bile concentrations on acidactivity of UTKG it was found that active acid formation occurred at the concentrations up to 4 % NaCl in cultivation medium (boiled milk) and at 20 % bile and 0.45 % phenol. It proves microbial association to be capable of withstanding adverse gastrointestinal conditions and continue developing.

1 illus, 3 tables, 36 ref

024648   ELAMVAZHUDI B, VELMURUGAN V, GOPALAKANNAN S (Mechanical Engineering Dep, IFET Coll of Engineering, Villupuram- 605 108, Email: elamvazhudib@yahoo.in) : Mechanical characteristics of conch shell polymer matrix composites. Bull Pure Appl Sci- Sect F 2018, 37F(1), 101-9.

Innovative materials have found many applications in many areas of daily life for quite some time. Conventional materials like glass, boron nitrate, silicon carbide and metallic binders belong to the group of ceramic matrix composite materials. Substantial development in the field of polymer composites has been achieved in recent years, so that they could be introduced into the most important applications. These new innovative materials open up unlimited possibilities for modern material science and development. With this in mind, in this work a new polymer matrix composite material is developed with the conch shell material called as aragonite and epoxy resin. Test specimens prepared by in situ fabrication method with different volume percentage of conch shell particles. Mechanical characteristics such as tensile strength, impact strength and hardness values were determined. In addition, microstructural analysis reveals that conch shell materials have a crossed-lamellar microstructure and the angle between two second-order lamellae is 70–90°. Fracture morphologies indicate that crack deflection is the major toughening mechanisms.

12 illus, 1 table, 11 ref

024647   ELAMVAZHUDI B, MADHESWARAN K, GOPALAKANNAN S (Mechanical Engineering Dep, IFET Coll of Engineering, Villupuram- 605 108, Email: elamvazhudib@yahoo.in) : Investigation of dynamic characteristics on GFRP composites with egg shell particles. Bull Pure Appl Sci- Sect F 2018, 37F(1), 93-100.

New engineering functional materials are required to the designers for many valid reasons which are stronger, lighter or less expensive compared with traditional materials. Polymer composite is the essential engineering material in the field aerospace, automobile and defense applications. In this research work, Glass fiber reinforced polymer composites with egg shell particles modified epoxy laminates were fabricated and dynamic mechanical characteristics were analyzed. Egg shell particles are dispersed with different volume fractions (0 %, 5 %, 7 %, 9 %) by mechanical stirring and ultra-sonication method. Laminates were prepared with hand layup method. Dynamic mechanical characteristics were examined by impulse excitation technique under fixed- free boundary conditions. In addition, mechanical properties such as impact strength and hardness of the composites were also determined

8 illus, 3 tables, 12 ref

024646   ARUN A, VELMURUGAN, PRAVEEN KUMAR T (IFET Coll of Engineering, Tamil Nadu- 605 108, Email: sudagar19@gmail.com) : Production of bio-oil from banana peduncle by thermal cracking process. Bull Pure Appl Sci- Sect F 2018, 37F(1), 88-92.

Depletion of the conventional fuel has been increases day by day, due the more utilization and lesser production. As the world has to think the alternative way for the energy resources. At this situation search for an alternative fuel research has been increased. Among various researches the waste material into useful energy (gas, oil) has became an important research and various techniques were involved. Thermo chemical method is one of the techniques of convert the waste into useful energy. In this work Banana peduncle (BP), which is consider as an agricultural solid waste. Banana peduncle (BP) is considered as the raw material for the pyrolysis process. Based on the Thermo gravimetric analysis pyorlysis experiment is carried out find its maximum oil yield temperature. The other products during the pyolysis are char and gas. The pytoltyic oil is analysed by using FTIR to find the various components present in it.

4 illus, 2 tables, 7 ref

023688   BHARADWAJ P, JOHN V (Electrical Engineering Dep, Indian Institute of Science, Bangalore- 560 012, Email: bharadwaj@ee.iisc.ernet.in) : Linearised model for PV panel power output variation with changes in ambient conditions. Sadhna 2017, 42(12), 2183–87.

In closed loop control of PV systems it is important to model the small signal variation of PV panel array output with ambient conditions, namely irradiation and temperature. Changes in these conditions act as a disturbance to the system, but this disturbance needs to be reflected in terms of the quantity being controlled, which can be the PV panel current or the real power. In this work a linearised model is derived to relate the change in system input, namely: irradiance and temperature, with its output, namely: array current and power. The proposed model is experimentally verified with tests run on PV panels, when they are subjected to varying irradiation and temperature conditions in the laboratory. The experimental results confirm the accuracy of the linearised PV panel model.

3 illus, 3 tables, 17 ref

023687   MUTHURAJ M, NITHYAPRIYA K (Civil Engineering Dep, Coimbatore Institute of Technology, Coimbatore- 641 014, Email: m_p_muthuraj@rediffmail.com) : Experimental studies on multicellular GFRP bridge deck panels under static and fatigue loading. Sadhna 2017, 42(12), 2171–81.

This paper presents the experimental investigations carried out on hand lay-up prototype multicellular glass fibre reinforced polymer (GFRP) composite bridge deck panels under static and fatigue loading. Various sustainability aspects with regard to GFRP structural members were discussed. The aspects include (i) social development; (ii) environmental protection; and (iii) economic development. The GFRP material properties were evaluated by using (i) micromechanics; (ii) simplified composite micromechanics equations (Chamis); (iii) carpet plots; and (iv) equations proposed by Tsai–Hahn. GFRP members with various cross sections were tested to decide the better performance under flexural loading and found that GFRP with hollow section performs better. For the optimised cross-section dimensions, six multi-cellular GFRP composite bridge deck panels of size 1250 mm x 333 mm x 150 mm (l x b x d) were fabricated by hand lay-up process and tested for static and fatigue loading. It was observed from the experiment that during testing the bridge deck panel, no load shedding was observed even though the resin started cracking. At ultimate load, there was a loud cracking sound and the specimen load shedding occurred suddenly. Factor of safety for load and deflection was computed. From the fatigue experiments, it is observed that the percentage reduction in stiffness is approximately 12% for 500,000 cycles.

13 illus, 8 tables, 24 ref

023686   RODRIGUEZ-PRIETO A, CAMACHO A M, SEBASTIAN M A (Manufacturing Engineering Dep, Coll of Industrial Engineers, Spain, Email: alvaro.rodriguez@invi.uned.es) : Quantitative analysis of prediction models for hot cracking in industrial stainless steels using standardized requirements. Sadhna 2017, 42(12), 2147–55.

In this paper, a systematic analysis of different methods of d-ferrite estimation is carried out based on the well-known relationship between d-ferrite content and hot cracking in stainless steels. Additionally, the influence of certain chemical requirements on d-ferrite stabilization and their relationship to hot cracking is evaluated by the application of a deterministic algorithm based on stringency levels. The results obtained from the application of the stringency level method and prediction diagrams permit the selection of the best option among materials according to their standardized specifications. In addition, the advantage of this integrated method is that we can evaluate particular elemental influences and assign relative weightings to create a database for materials selection.

4 illus, 8 tables, 52 ref

023685   KAWALE S, CHANDRAMOHAN V P (Mechanical Engineering Dep, National Institute of Technology, Warangal- 506 04, Email: vpcm80@gmail.com) : CFD simulation of estimating critical shear stress for cleaning flat soiled surface. Sadhna 2017, 42(12), 2137–45.

Turbulent water jet impingement on surfaces has several applications in cleaning processes and heat transfer equipment. This work aims to find the effect of variation in inlet jet Reynolds number on variation wall shear stress and pressure on surfaces encountered in equipment used in food processing industries, particularly in the dishwasher domain. Computational fluid dynamics simulation of turbulent water jet for Re [6000 is performed in ANSYS Fluent. Simulations are run using the volume of fluid Eulerian multi-phase model with the standard k-e turbulence modeling. Discretisation is carried out by the implicit unsteady solver scheme, and the SIMPLE algorithm is chosen to solve the set of equations. Shear stress at Re = 6300 is validated with experimental results. There is drastic variation in the static pressure and wall shear stress with Reynolds number. Critical jet exit velocity required for effective cleaning of flat plate is found to be 3 m/s.

10 illus, 17 ref

023684   MISHRA R N, MOHANTY K B (Electrical Engineering Dep, National Institute of Technology, Rourkela- 769 008, Email: rabimishra2014@gmail.com) : Implementation of feedback-linearization-modelled induction motor drive through an adaptive simplified neuro-fuzzy approach. Sadhna 2017, 42(12), 2113–35.

A simple modified version of neuro-fuzzy controller (NFC) method based on single-input, reduced membership function in conjunction with an intuitive flux–speed decoupled feedback linearization (FBL) approach of induction motor (IM) model is presented in this paper. The proposed NFC with FBL remarkably suppresses the torque and speed ripple and shows improved performance. Further, the modified NFC is tuned by genetic algorithm (GA) approach for optimal performance of FBL-based IM drive. Moreover, the GA searches the optimal parameters of the simplified NFC in order to ensure the global convergence of error. The proposed simplified NFC integrates the concept of fuzzy logic and neural network structure like a conventional NFC, but it has the advantages of simplicity and improved computational efficiency over the conventional NFC as the single input introduced here is an error (speed and torque) instead of two inputs, error and change in error, as in the conventional NFC. This structure makes the proposed NFC robust and simple as compared with conventional NFC and thus, can be easily applied to real-time industry application. The proposed system incorporated with different control methods is also validated with extensive experimental results using DSP2812. The effectiveness of the proposed method using FBL of IM drive is investigated in simulation as well as in experiment with different working modes. It is evident from the comparative results that the system performance is not deteriorated using the proposed simple NFC as compared to the conventional NFC; rather, it shows superior performance over PI-controller-based drive.

17 illus, 1 table, 19 ref

023683   MISRA H, JAIN A K (Electrical Engineering Dep, Indian Institute of Technology, New Delhi- 110 016, Email: himanshu00129@gmail.com) : Control of AC–DC grid side converter with single AC current sensor. Sadhna 2017, 42(12), 2099–12.

Conventionally, two AC side current sensors are needed in vector control of grid side converter for AC–DC bidirectional power conversion. The present paper proposes a technique where the control can be achieved with the use of only one AC side current sensor. The control principle utilises the information of unsensed second current sensor for its estimation, which is embedded and readily available in conventional control technique itself. In the proposed method, the grid side d–q axis reference currents of the current controllers are used for estimation of b-axis component of grid current, while the a-axis component of grid current is calculated by one AC side current sensor. Effect of voltage unbalance on the control is also studied in this paper. The proposed control is validated with detailed simulation and experimental observations for both steady-state and transient conditions. The proposed control gives satisfactory performance.

16 illus, 1 table, 19 ref

023682   COMERT S E, YAZGAN H R, SERTVURAN I, SENGUL H (Industrial Engineering Dep, Sakarya Univ, Turkey, Email: serape@sakarya.edu.tr) : A new approach for solution of vehicle routing problem with hard time window: An application in a supermarket chain. Sadhna 2017, 42(12), 2067–80.

In this study, a vehicle routing problem with hard time windows (VRPHTW) that appears to meet demands of customers’ service within time intervals in a supermarket chain is solved. In VRPHTW, to reach a solution by an exact method is quite difficult and sometimes impossible if number of constraints is large enough (i.e., NP-hard), and solution time of a VRPHTW grows exponentially. As the size of the problem grows, a near optimal solution can be found using a heuristic method. A hierarchical approach consisting of two stages as ‘‘cluster-first route-second’’ is proposed. In the first stage, customers are assigned to vehicles using three different clustering algorithms (i.e., K-means, K-medoids and DBSCAN). In the second stage, a VRPHTW is solved using a MILP. The main contribution of the article is that the proposed hierarchical approach enables us to deal with a large size real problem and to solve it in a short time using the exact method. Finally, the proposed approach is employed on a supermarket chain. An instance of the algorithm is demonstrated to illustrate the applicability of the proposed approach and the results obtained are highly favourable.

4 illus, 13 tables, 68 ref

023681   KARMAKER T, DAS R (Civil Engineering Dep, Thapar Univ, Patiala- 147 004, Email: tapas1976@gmail.com) : Estimation of riverbank soil erodibility parameters using genetic algorithm. Sadhna 2017, 42(11), 1953-63.

Determination of the erodibility parameters, such as critical shear stress and erodibility coefficient, are necessary before estimating the annual bank erosion (or bank retreat) at river reaches. However, in many cases, the river site is inaccessible making it difficult to assess the soil parameters either by in situ tests or by laboratory experiments. In this study, Genetic Algorithm (GA)-based optimisation technique was used to estimate the erodibility parameters of middle reaches of the Brahmaputra River in India. Two approaches were followed. At first, erodibility parameters were estimated using daily stage records at a selected site. Secondly, based on the annual observed bank erosions (bank retreat) from satellite images, erodibility parameters were estimated in three different river reaches. All these results were compared with that from a previous study using in situ jet tests. Annual bank erosions (bank retreat) were estimated using the median values of the erodibility parameters. The results agree well with the average observed annual bank erosion of these river reaches. In addition, the effects of measurement errors and optimisation algorithms on the parameter estimation were analysed. Sensitivity analysis of the parameters in GA was evaluated and it was found that GA can be utilised in the data-scarce regions to estimate the average erodibility parameters.

8 illus, 5 tables, 35 ref

023680   SHIH M, TUNG S (Civil and Environmental Engineering Dep, National Univ of Kaohsiung, Taiwan- 54561, Email: shtung@nuk.edu.tw) : A method for correcting radial distortion based on verifying the planarity of specimens. Sadhna 2017, 42(11), 1943-52.

Image distortion is inevitable when an image is captured through a lens. While the digital image measurement technique is getting popular, image distortion problem can result in significant error. A new distortion correction method is proposed in this study. The proposed method is based on the fact that a flat surface should keep flat when it is measured using three-dimensional (3D) digital image measurement technique. The 3D digital image measurement technique adopted in this research is the simplified 3D digital image correlation (DIC) method. Because radial distortion has a more noticeable influence than other types of distortions, this method deals only with radial distortion. A few experiments are carried out in this study to verify the correctness of this method and its accuracy. Both simulated data and actual image data are adopted in these experiments. The results show that this method can achieve a good accuracy. The standard deviations caused by random errors are about the same order as the random errors. It also shows that this method is suitable for both large and small distortion conditions.

9 illus, 8 tables, 14 ref

023679   JELIA P R, AGRAWAL A, SINGH R K, JOSHI S S (Mechanical Engineering Dep, Indian Institute of Technology, Mumbai- 400 076, Email: ssjoshi@iitb.ac.in) : Design of textured surfaces for super-hydrophobicity. Sadhna 2017, 42(11), 1915-27.

Although the Cassie–Baxter and Wenzel equations predict contact angles for relative dimensions of micro-pillars on textured surfaces, the absolute pillar dimensions are determined by trial and error. Alternatively, geometries of natural super-hydrophobic surfaces are often imitated to design textured surfaces. Knowing the limitations of both the approaches, this work presents a constraint minimization model on the basis of Cassie– Baxter equation to determine the absolute dimensions of square micro-pillars on a textured surface so as to maximize the contact angle. The constraints are derived based on the limiting physical conditions at which spontaneous breakdown of super-hydrophobicity takes place. The single-droplet numerical simulations on textured surface gave the duration for which super-hydrophobicity is sustained. The model demonstrated that the round edged pillars, arising out of fabrication imperfections, reduce the height of the pillars without significantly compromising on the contact angle. The measurement of contact angle on the fabricated textured surfaces was found to be in agreement with the model predictions when the fabricated pillars had fairly uniform dimensions. The proposed approach is sufficiently general that its application can be extended to design other textured surfaces.

18 illus, 5 tables, 23 ref

023678   DURU C, ANI C (Electronic Engineering Dep, , Nigeria, Email: chinedu.duru@unn.edu.ng) : A statistical analysis on the leak detection performance of underground and overground pipelines with wireless sensor networks through the maximum likelihood ratio test. Sadhna 2017, 42(11), 1889-99.

Leaks in pipelines of the oil and gas industry are an economic and environmental problem that needs to be detected early and effectively. Wireless sensor networks (WSNs) have been researched as one of those technologies to be used in the remote monitoring of pipeline infrastructure. The idea of using tiny sensor nodes on pipelines seemingly provides industries with effective and reliable real-time monitoring, and better coverage density per area. The benefits are apparent in the deployment of WSNs for pipeline monitoring. However, what really lacks is an actual comparison in the detection performance between deployment in overground pipelines and underground pipelines. Extensive research has been going on the use of wireless underground sensor networks for a number of applications. This paper attempts to provide a statistical insight on the concepts of leak detection performance of WSNs when deployed on overground and underground pipelines. The approach in the study employs the hypothesis testing problem to formulate a solution on the detection plan. Through the hypothesis test, the maximum likelihood ratio scheme is used to provide an optimal performance analysis of the detection idea. The test also takes into consideration the signal to noise ratio performance of the two settings of underground and overground and is crucial in bringing up a conjecture on the performance of detection. As would be shown in the paper, thresholds, determined by probability, are the key in ensuring a good detecting performance for the WSN.

12 illus, 2 tables, 41 ref

023677   WAGHMARE M, REDDY K T V (Electronics and Telecommunication Engineering Dep, Sardar Patel Institute of Technology, Mumbai- 400 058, Email: madhavi@gmail.com) : A novel structure of photonic crystal fibre for dispersion compensation over broadband range. Sadhna 2017, 42(11), 1883-7.

This paper studies a novel structure of photonic crystal fibre (PCF) for dispersion compensation at broadband wavelengths. The application of broadband is investigated using a design model based on combination of modal properties and dispersion compensation. The newly designed PCF with defect introduced is recorded over transmission spectrum range 146.7–256.98 THz, i.e., 1.16–2.04 lm. The modal characteristics and dispersion compensation of 2D PCF with circular air holes defect introduced are investigated and compared to those of conventional hexagonal 2D PCF. Changes in bandwidth behaviour are also observed by changing refractive index and geometric parameter of PCF.

6 illus, 2 tables, 16 ref

023676   SINGH R, CHAUDHARY H, SINGH A K (Mechanical Engineering Dep, Malaviya National Institute of Technology, Jaipur- 302 017, Email: ramanpreet.gurdutta@hotmail.com) : A new hybrid teaching-learning particle swarm optimization algorithm for synthesis of linkages to generate path. Sadhna 2017, 42(11), 1851-70.

This paper proposes a novel hybrid teaching–learning particle swarm optimization (HTLPSO) algorithm, which merges two established nature-inspired algorithms, namely, optimization based on teaching– learning (TLBO) and particle swarm optimization (PSO). The HTLPSO merges the best half of population obtained after the teacher phase in TLBO with the best half of the population obtained after PSO. The population so obtained is used subsequently in learner phase of TLBO. To validate the proposed algorithm, five constrained benchmark functions are considered to prove its robustness and efficiency. The proposed algorithm is applied to synthesize four-bar linkage for prescribed path. It is found that the HTLPSO performs better than other single nature-inspired algorithms for path synthesis problem in mechanism theory. Hence, HTLPSO may prove to be an important tool for mechanism design to follow the prescribed path.

12 illus, 6 tables, 40 ref

023675   SONG P, JIE-SHEW, ZHOU T, YANG T L, NI G (Coll of Chemistry and Chemical Engineering, Yinchuan- 750 021, Email: yang_tl@nxu.edu.cn) : Synthesis of [N-bis(4-methyl benzene-diamino formyl) methyl phosphonic acid] and its europium (III) complex and its application as DNA electrochemical sensor. Indian J Chem Technol 2017, 24, 608-15.

The new tripod ligand [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex (Eu(pic)3L) have been synthesized and characterized by TG-DSC, IR spectroscopy, UV-vis spectroscopy, elemental and molar conductance analysis. The experimental results show that the ligand forms the 1:1 complex with europium picrate. The results of UV-vis spectroscopy and cyclic voltammetry indicate that there are intercalation interaction between DNA and Eu(pic)3L. When the Eu(pic)3L is regarded as DNA hybridization probe and used in the study of DNA electrochemical sensor, no obvious electrochemical signal response could be found with Eu(pic)3L under the effect of modified electrodes single-strand DNA testing. However, obvious electrochemical signal response is found when it is under the effect of double-stranded DNA testing. It indicates that the biosensor can discriminate well between the complementary sequences from the base-mismatched and the non-complementary sequences. So Eu(pic)3L can be used as a biosensor to discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences.

10 illus, 24 ref

023674   PADMAVATHY K S, MURALI A, MADHU G, SAHOO D K (Chemical Engineering Dep, Government Engineering College, kerala- 680 009, Email: padma426@gmail.com) : Adsorption of hexavalent chromium (Cr(VI)) from wastewater using novel chitosan/halloysite clay nanocomposite films. Indian J Chem Technol 2017, 24, 593-600.

Nano composite films have been prepared in the laboratory by impregnating halloysite nanoclay on chitosan matrix. The functional groups present in the composite films have been investigated using Fourier transform infrared spectroscopy (FTIR) and morphological structure of the synthesized films are analysed using scanning electron microscopy (SEM). Thermo gravimetric analyser (TGA) is used for investigating the thermal stability of the composite. The films are used for adsorption of hexavalent chromium from wastewater. Optimum pH for adsorption is 3.0 and all other experiments are conducted at pH 3.0. It has been observed that adsorbent dosage required is very less when compared to pure chitosan as adsorbent. The adsorption capacity is also very high when compared with pure chitosan for removal of Cr (VI) under the same conditions. The equilibrium studies have been conducted and data is fitted to the Langmuir equation. The kinetic studies reveal that the adsorption mechanism is pseudo second order. The study shows that the chitosan/halloysite clay can be used as a promising adsorbent for hexavalent chromium uptake from wastewater.

5 illus, 22 ref