041313   BAJAJ R, DIXIT A R, TIWARI A K, CHAUHAN N K (Mechanical Engineering Dep, Indian Institute of Technology (ISM), Dhanbad - 826 004, Email: rajeshbajaj@jssaten.ac.in) : Machining performance enhancement of EN-31 diesteel using MWCNT mixed rotary EDM. Indian J Eng Mater Sci 2020, 27(2), 309-19.

The present study investigates the influence of adding multi-wall carbon nanotube (MWCNT) into the dielectric fluid of  electric discharge machining (EDM) in terms of material removal rate (MRR), surface roughness (SR) and surface topology of EN-31 die steel using Cu electrode. A customized rotary electrode set-up has been developed to compare the performance improvement of powder mixed rotary electrical discharge machining (PMREDM) as compared to powder mixed electrical discharge machining (PMEDM) and conventional EDM. The present study attempts to investigate the optimization of process parameters of MWCNT mixed rotary EDM of EN-31 die steel using response surface methodology (RSM) and genetic algorithm (GA) in terms of MRR and SR. The optimization results show that MWCNT mixed rotary EDM shows highest value of MRR (9.72 mm³/min) and lowest value of SR (R_a = 2.03 µm), which are approximately 46.17 % higher and 45.43 % lower than conventional EDM values respectively. Further, various combinations of optimal values of MRR and SR and their corresponding input parameters setting have been shown in pareto table created by multi-objective optimization GA technique available in MATLAB. Finally, field emission scanning electron microscope (FESEM) analysis of MWCNT mixed rotary EDM and EDM surfaces is carried out which revealsthat MWCNT mixed rotary EDM shows better surface topography as compared to EDM process.

10 illus, 6 tables, 36 ref

041312   KUMAR M (Mechanical Engineering Dep, Malaviya National Institute of Technology, Jaipur - 302 017, Rajasthan, Email: mukeshyss@gmail.com) : Application of hybrid AHP-TOPSIS technique in analyzing the braking performance sensitivity of organic-ceramic fibrous reinforced friction composites. Indian J Eng Mater Sci 2020, 27(2), 300-8.

In this research work, brake pad friction composite materials based on binary and ternary combinations of ceramic-organic fibres have been realized, following evaluation of braking performance parameters on Krauss friction testing machine adopting ECE R-90 regulations and PVW-32 standard test protocol.  The obtained experimental performance data has been further used for the assessment of performance based ranking using hybrid AHP-TOPSIS technique.  The order of relative weights or priority order of performance defining criteria as obtained by AHP is µ-Performance (µ_p) ~ Stability Coefficient (α) > % µ-Recovery > Wear (g) > % µ-Fade > DTR (°C) > Friction Fluctuations (∆µ) > Variability Coefficient (γ). The consistency verification highlights that λ_max = 8.0391, consistency index = 0.0045579, and consistency ratio (CR) = 0.00323 << 0.1 (upper bound limit for acceptance of CR). The aramid fibre 5-7.5 wt.% in combination with other fibres 25-22.5 wt.% (for binary combination) and 12.5/12.5 - 11.25/11.25 wt.% (for ternary combinations) has been found to impart the best overall performance level relative to other combos of the friction composites under investigation. The sensitivity analysis of performance defining criteria's and ranking orders of the compositions in the respective formulations gives robust/stable observations as the weights changes from ± (10-20) %. The hybrid AHP-TOPSIS technique in-conjunction-with sensitivity analysis might sever as an effective tool in the decision making whenever there are finite material alternatives and finite performance determining criteria having conflicting nature.

1 illus, 7 tables, 26 ref

041311   SHUAI T, ZHENKUN M, BO S (Liaoning Univ of Science and Technology, Anshan 114051, China, Email: tian_shuai129@126.com) : Anchoring the CFRP strengthening of concrete bridge decks: A comparison of methods. Indian J Eng Mater Sci 2020, 27(2), 288-99.

Debonding failures are a common problem in concrete bridge decks strengthened with adhesively attached carbon-fibre reinforced polymer (CFRP) strips. Accordingly, in this study, rectangular concrete slabs strengthened with CFRP have been experimentally evaluated to simulate the strengthening of T-beam and box girder slabs. The resulting static load data have been used to compare the effects of four different anchoring methods in terms of crack distribution, deflection, reinforcing steel strain curve, and CFRP strain distribution. The most suitable bridge deck strengthening anchoring method has been then identified and analysed using extant strengthening design methods. The results show that the most practical anchoring method is the use of open CFRP strips attached with concentrated adhesive. The findings of this study indicate that when strengthening T-girder bridges, more than two CFRP anchorage strips should be evenly spaced within the extension of the anchorage length, while for box girder bridges, even more evenly spaced strips should be used. This research and its conclusions can be used as a reference for the improved design of bridge deck strengthening.

10 illus, 2 tables, 22 ref

041310   ZUNO-SILVA J, KEDDAM M, ORTIZ-DOMÍNGUEZ M, ELIAS-ESPINOSA M, ARENAS-FLORES A, CERVANTES-SODI F, REYES-RETANA J A (USTHB, Bab-Ezzouar, Algiers, Algeria, Email: keddam@yahoo.fr) : Growth kinetics of Fe₂B layers formed on the AISI 4150 steel by different approaches. Indian J Eng Mater Sci 2020, 27(2), 277-87.

In the present work, the AISI 4150 steel has been pack-borided in the temperature range of 1123-1273 K for a treatment time of 2 to 8 h. The mixture of powders containing 20 % B₄C, 10 % KBF₄ and 70 % SiC has been used for producing a single boride layer (Fe₂B) at the surface of AISI 4150 steel. The presence of Fe₂B phase has been confirmed by XRD analysis. The SEM observations have been done to investigate the morphology of boride layers and measure their thicknesses. The cohesion of boride layers has been evaluated by using the Daimler-Benz Rockwell-C indentation technique. The borided sample at 1173 K for 8 h has shown a best cohesion of boride layer to the substrate in comparison to the sample treated at 1173 K during 2 h. Kinetically, different approaches have been used to estimate the boron diffusion coefficients in the Fe₂B layers and to predict the value of Fe₂B layer thickness obtained at 1253 K for a treatment time of 2.5 h. The estimated values of activation energies for boron diffusion in AISI 4150 steel have been in the range of 193.45 to 199.74 kJ mol^-1. These values of activation energies have been depended on the diffusion models used. In addition, a good agreement has been observed between the experimental value of Fe₂B layer thickness obtained at 1253 K for 2.5 h with the predicted values from these different diffusion models.

9 illus, 4 tables, 68 ref

041308   LÓPEZ-VÁSQUEZ A, PATAQUIVA-MATEUS A, DELGADO-NINO P (Chemical Engineering Dep, Nacional de Colombia Univ, Manizales 170003, Colombia, Email: aflopezv@unal.edu.co) : Microspheres based on black sand mineral as a photocatalyst for photocatalytic hydrogen production under UV light. Indian J Eng Mater Sci 2020, 27(2), 256-66.

Frequently, black sand from coastal deposits is a magnetic ore with a complex structure that is composed principally by iron, titanium and silica oxides, and metals such as vanadium, chromium, nickel, strontium, etc. This material could be used in oxidation/reduction processes as a photocatalyst doped naturally. However, its surface area low and the mass transfer constraints caused by the cluster formation in bulk reaction due to its magnetic character, limits the photocatalytic performance. Microspheres of black sand have been prepared by a simple associating method with alginate-Na and calcined under oxidizing atmosphere at 1100 °C. These have been characterized by XRF spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area analysis, XRD diffraction, N₂ adsorption/desorption measurements, FT-IR spectroscopy, differential thermal thermogravimetric analysis, and UV-Vis spectrophotometry. The catalytic activity for photocatalytic hydrogen production from EDTA solutions under UV light irradiation, using the response surface methodology in order to determine the optimum conditions of the process, has been tested. At calcination temperature, rounded microspheres with rough surface, have had apparent density different from the raw material and although the specific surface of the microspheres decreased owing to surface sintering, the chemical composition has been similar compared with the starting material. Due to their buoyancy in the suspension, the hydrogen production due to the contact between photons that entered into suspension and the as-prepared microspheres, has been favored.

11 illus, 4 tables, 59 ref

041307   KUMAR A, GULATI V (Mechanical Engineering Dep, Shree Guru Gobind Singh Tricentenary Univ, Gurugram - 122 505, Haryana, Email: ajay.kumar30886@gmail.com) : Optimization and investigation of process parameters in single point incremental forming. Indian J Eng Mater Sci 2020, 27(2), 246-55.

Single point incremental forming (SPIF) process is an innovative and dies-less forming technique to produce various useful shapes for small batch size economically. This process exempts expensive and complex tooling which is used in traditional sheet forming processes. Study of forming force and thickness reduction of the components formed by SPIF process would help the process engineers to provide some guidelines regarding the implementations of this process to mainstream of manufacturing industries. In this work, seven impact factors of this process have been exploited to optimize SPIF process using Taguchi method as a design of experiment (DoE) technique. The objective of current work is to optimize the forming forces and thickness reduction of the formed conical frustums for a given set of factors for operation sustainability. The predictive models have also been generated for estimating optimal characteristics of the process. The predictive model estimated the response characteristics of the SPIF process effectively and accurately.

9 illus, 9 tables, 29 ref

041306   KATARIA M, MANGAL S K (Mechanical Engineering Dep, Gautam Buddha Univ, Greater Noida, Uttar Pradesh - 201 308, Email: mukulkataria89@rediffmail.com) : Excellence of Al-metal matrix composite fabricated by gas injection bottom pouring vacuum stir casting process. Indian J Eng Mater Sci 2020, 27(2), 234-45.

The present study has envisaged an advance technique, gas injection bottom pouring vacuum stir casting process, for the casting of metal matrix composite (MMCs). This process has been eliminated several manual processing steps of conventional stir casting hence concerns about the workers’ safety and its bottom pouring mechanism & vacuum mould chamber improve the properties of the fabricated MMC. An Al/(10wt % Al₂O₃) MMC has been fabricated by the proposed technique and characterized for the mechanical and microstructural properties. An experimental plan based on Taguchi L₁₆ orthogonal array has also been used to investigate the factors affecting the wear behaviour. The fabricated Al-MMC has a density of 2.65 gm/cc, micro-hardness of 73.3 HV, tensile strength of 220 MPa and wear rate of 0.0137736 mm³/m, implying in substantial improvements from the matrix Al-alloy. A comparative study with the available literature has been carried out to investigate the possibilities of the proposed method in today’s manufacturing world. The results concluded that the fabricated MMC has significantly enhanced the properties of MMCs when compared to the existing casting techniques. From the results of present study, it has been suggested to employ the process in industrial & allied applications and especially in the research institutes where the researchers are not very skilled for the casting operations.

10 illus, 5 tables, 52 ref

041305   KEDDAM M, MAKUCH N, KULKA M, MIKLASZEWSKI A (USTHB, Algiers, Algeria, Email: keddam@yahoo.fr) : Mechanical properties and kinetics of boride layers on AISI D2 steel produced by plasma paste boriding. Indian J Eng Mater Sci 2020, 27(2), 221-33.

In the present study, the AISI D2 steel has been treated by the plasma paste boriding process using a gas mixture of 70 % H₂-30 % Ar with 70 % of borax and 30 % SiC. The boriding treatment has been carried out at 700, 750 and 800 °C for an exposure time of 3 to 7 h. The plasma paste borided samples have been investigated by various techniques such as scanning electron microscopy, optical microscopy, XRD analysis, micro-hardness Vickers and the rockwell-C adhesion tests. The fracture toughness has also been measured on the plasma paste borided samples under different values of indentation load. From a kinetic point of view, the boride layers have obeyed the parabolic growth law. The value of boron activation energy for AISI D2 steel has been estimated as 130 kJ mol^–1 using our experimental results. In addition, this obtained activation energy has been compared to the literature data.

14 illus, 6 tables, 29 ref

041304   ASLAN Z, KIRATLI S (Mechanical Engineering Dep, Sivas Cumhuriyet Univ, Sivas 58140, Turkey, Email: zuleyaslan@cumhuriyet.edu.tr) : Experimental determination of residual flexural strength and critical buckling load of impact-damaged glass/epoxy laminates. Indian J Eng Mater Sci 2020, 27(2), 209-20.

The main objective of this research is to find experimentally the effect of impact damage on the flexural strength of glass fiber/epoxy laminated composite materials at two different test conditions. The other objective is to determine the critical buckling load of laminated composite material after impact loading. Thus, the loss of flexural and buckling performances of the damaged material has been established by comparison with the undamaged material. Initially, angle-ply laminated composite plates with rectangular shaped have been subjected to impact load at different energy levels by using a drop-weight testing machine and impact damage has been created. To find the residual flexural strength, four-point bending tests have been carried out. Four-point bending specimens have been cut from the damaged area of the middle of the laminated plates and have been positioned in two different ways according to the face subjected to the impact. For buckling tests, a unidirectional compression load has been applied to the impacted specimens with the size of 100 mm x150 mm. According to the four-point bending test results, the flexural strengths of the specimens subjected to impact at 10 J and 30 J have decreased approximately 25 and 42 %, respectively. Similarly, the reductions in critical buckling loads of specimens subjected to impact at 10 J and 40 J are approximately 16 and 32 %, respectively. Consequently, the impact load significantly reduces the flexural and buckling performances of laminated glass/epoxy composites. Furthermore, the positioning of the four-point bending test specimen affects the flexural strength.

13 illus, 2 tables, 30 ref

041302   MAZURCHEVICI A D, NEDELCU D, POPA R (Technical Univ of Iasi, Iasi, Romania, Email: nedelcu1967@yahoo.com) : Additive manufacturing of composite materials by FDM technology: A review. Indian J Eng Mater Sci 2020, 27(2), 179-92.

The additive manufacturing known also as “3D printing” or “rapid prototyping” is a present manufacturing method (compared to classic manufacturing methods) where layers of material are deposited at a time (successively) until a finished product is obtained. Depending on the phenomenon, material (in solid, liquid or powder state) used by the 3D printing equipment, a solid part, can be achieved using processes as: binder jetting,extrusion, material jetting, direct energy, vat photo-polymerization and powder bed fusion. In the present paper, we have summarized some knowledge regarding the 3D printing technologies, fused deposition modeling (FDM) prototyping method, and different types of test regarding PLA material properties (tensile test, flexural test). The FDM technology has registered benefits as cost, product quality, functionality and manufacturing time, continuously optimized and adopted by more and more companies, research institutes and consumers.

17 illus, 4 tables, 33 ref

041301   WANG H, ZHANG Z, QIAN H, SONG G, WANG J, FAN F (Harbin Institute of Technology, Harbin 150000, China, Email: 16B933030@hit.edu.cn) : On the axial bearing capability of construction steel tube considering the uniform corrosion effect. Indian J Eng Mater Sci 2020, 27(2), 168-78.

To study the law of corrosion on the mechanical properties of the components used in spatial steel structures and obtain the load-carrying capability of circular steel tubes under varying degrees of corrosion, experiments on a periodic spray have been designed to study the accelerated corrosion and axial loading of tubes without a protective layer. The experiment results show that the yield and ultimate load-carrying capacities of the components are heavily influenced by the corrosion, the latter being more sensitive to corrosion, and that a good functional relationship exists between the weight loss ratio and the load-carrying capability of the corrosive components. In addition, a finite element model of a circular steel tube experiencing corrosion has been established using ANSYS with an equivalent cross-section reduction method to simulate of the experiment results. The simulation results agree well with the experiment results, which effectively indicates that the corrosion of the steel tube components obeys the uniform corrosion law. And the equivalent cross-section reduction method also possesses good reliability. The results of the study provide a technical reference for research on the mechanical properties of larger building components such as circular steel tubes experiencing corrosion.

22 illus, 5 tables, 28 ref

041300   SHARMA M, GOYAL D K, KAUSHAL G (Mechanical Engineering Dep, I. K. Gujral Punjab Technical Univ, Kapurthala - 144 603, Email: erdeepakgoyal81@gmail.com) : Tribological investigation of HVOF-spray Cr₃C₂-25NiCr and WC-10Co-4Cr coated turbine steel under varied slurry erosion conditions. Indian J Eng Mater Sci 2020, 27(2), 150-67.

In this work, high velocity oxy fuel (HVOF) method based spray coatings namely Cr₃C₂-25NiCr and WC-10Co-4Cr have been deposited on AISI304 turbine steels. An attempt has been made to analyze the coatings under accelerated slurry erosion conditions by employing a laboratory-developed slurry erosion testing set-up. The testing has been performed under varied conditions of slurry concentration, impact velocity and impact angle using the Taguchi approach. The microstructure of coating powder, erodent particles and deposited coatings have been studied using a scanning electron microscope (SEM) analysis. Erosion tests indicated that HVOF-spray Cr₃C₂-25NiCr and WC-10Co-4Cr coatings have been deposited on AISI304 steel exhibited significant improvements in the erosion resistance of AISI304 steel. The possible reason for such behaviour could be higher microhardness of HVOF-spray coatings in comparison with AISI304 bare steel. From SEM images of the samples taken prior and post slurry erosion tests, it has been observed that Cr₃C₂-25NiCr coating exhibited mixed (ductile and brittle) behaviour, though the WC-10Co-4Cr coating mostly demonstrated ductile behavior under conditions for erosion from the slurry. Apart from that, an attempt has been made to develop a functional equation based on the regression approach which could be employed to assess the erosion wear rate under a set of conditions. The predicted erosion wear results under varied conditions are in close relationship to experimental values.

25 illus, 9 tables, 32 ref

041299   SINGH R, SINGH B, GUPTA M, TARANNUM H (Plastics & Composites Div, CSIR-Central Building Research Institute, Roorkee – 247 667, Email: singhb122000@yahoo.com) : Composite building materials from natural fibers/ agro-forest residues. Indian J Eng Mater Sci 2020, 27(2), 137-49.

Interest in using renewable resources such as natural fibers and agro-forest residues as reinforcements/fillers in polymer matrices has grown considerably for making wood alternatives in view of their low cost, easy availability, saving in energy and pollution free-production. In this paper, an overview on the global perspective of natural fiber reinforced composites has been outlined with reference to their applications in buildings. Researches carried out on polymer composites based on natural fibers and agro-forest residues are briefly reviewed in terms of their physico-mechanical properties and performance characteristics. During fabrication, 30-50 wt % sisal/jute fibers in laminates/sheets, 50-60 wt % rice husk in extruded/injection moldings and ~95 wt % pine needles in boards have been used. The sandwich composites used in the doors ( jute laminate face, and polyester-urethane foam core) have a density of 500-610 kg/m³ and exhibited ~1.5 % weight loss when exposed to termites according to ASTM D 3345. Based on the results, sisal/jute composite panels/ door shutters, shuttering plates, rice husk/plastic profile frames and pine needle composite boards have been successfully manufactured at pilot plant scale. Techno-economics and sustainability issues related to these composites have also been discussed in order to develop confidence among users and entrepreneurs. A comparative assessment between the properties of these newly developed products and commercial specification gives a clear guideline for users about their suitability in large scale adaptation in practice.

6 illus, 6 tables, 71 ref

041298   SKONECZNY W (Silesia Univ, Bankowa 12 40 007 Katowice, Poland, Email: Wladyslaw.Skoneczny@us.edu.pl) : Effect of the base material condition on the structure and properties of Al₂O₃ oxide layers. Indian J Eng Mater Sci 2020, 27(1), 128-32.

The paper presents a new method for modelling oxide layers for tribology related needs. The most recent world trends in the machine-building sector, in particular with reference to piston machines, are heading towards reducing their lubrication and cooling. Hence, a question arises, what the upper layer of a ceramic material should be like in order to maintain low wear and low frictional resistance. An oxide layer for tribological needs has been formed on an AlMg₂ alloy as a result of hard anodizing in SAS electrolyte. This electrolyte enables the control of oxide layer production parameters, which allowed obtaining for the tests an oxide coating with a wide range of changes in porosity and micro-hardness µHV. Anodizing has been carried out by means of the direct-current method, using a stabilized feeder, GPR-25H30D, for a constant electrical charge density of 180 Amin/dm². A lead plate has been acted as the cathode in the anodizing process. By means of a scanning electron microscope (SEM), the surface morphology and structure, and the chemical composition of the layers have been analyzed.

4 illus, 12 ref

041297   FANGHUI H, XUAN Z, JUANHONG L (Civil Engineering Dep, Science & Technology Beijing Univ, Beijing, China, Email: hanyang-1120@163.com) : Relationship between the late-age hydration and strength development of cement-slag mortars. Indian J Eng Mater Sci 2020, 27(1), 120-7.

The relationship between the late-age hydration and strength development of cement-slag mortars have been investigated by measuring the compressive strengths and the non-evaporable water contents. The results show that the late-age strength increases with increasing the slag content. Increasing the fineness of slag makes greater contribution to the late-age strength improvement at high water to binder ratio than that at low water to binder ratio. At lower water to binder ratio, the increasing rates of compressive strength and non-evaporable water content are smaller. There is a linear relationship between the increasing rate of compressive strength and the increasing rate of non-evaporable water contents. The slope is almost the same for all the samples at constant water to binder ratio and decreases with decreasing the water to binder ratio.

5 illus, 2 tables, 25 ref

041296   RAI P (Mining Engineering Dep, Indian Institute of Technology (BHU), Varanasi - 221 005, Email: prai.min@itbhu.ac.in) : A comparative investigation of inter-row delay timing vis-a-vis some rock properties on high sandstone benches. Indian J Eng Mater Sci 2020, 27(1), 112-9.

The inter-row delay timing plays a pivotal role in any blast round as it not only influences the mechanism of fragmentation, but also offers a vast potential in improving the overall results of fragmentation. It is in this perspective that the current study presents a comparative investigation of the influence of inter-row delay timing on fragmentation in two different strength sandstone formation in large-scale, multi-row blast rounds of a two surface coal mines in India. The investigations are based on full-scale field blasts. The study highlights the role of p-wave velocity and brittleness vis-à-vis impedance to shock wave propagation during the initial as well as final stages of rock breakage. Given this, the role of shattering effect (in stronger sandstone formations) and heaving effect in weaker strength sandstone has been clearly established in the rock breakage mechanism. Furthermore, the study also suggests that for weaker sandstone, longer inter-row delay timing (15-25 ms/m of effective burden) yields the best fragment size results. Similarly, for stronger sandstone formation, shorter inter-row delay timing (10-17.85 ms/m of effective burden) yields the best fragment size results.

5 illus, 3 tables, 13 ref

041294   DANDAPAT N, GHOSH S (Bio-ceramics and Coating Div, CSIR- Central Glass and Ceramic Research Institute, Kolkata - 700 032, Email: sumana@cgcri.res.in) : Effect of alumina impurity on microstructure and properties of alumina based conventionally brazed joints. Indian J Eng Mater Sci 2020, 27(1), 96-103.

Mo-Mn metallization of alumina ceramics of different purity has been performed at 1400 °C for 10 min in moist hydrogen and nitrogen atmosphere. Nickel coating has been applied onto the metallized alumina ceramics at 1000 °C for 1 h in a reducing hydrogen atmosphere. Finally, metallized and nickel coated alumina ceramics has been brazed with another metallized and nickel coated alumina ceramics using CuAg filler alloy at 900 °C for 10 min in a vacuum furnace at 1×10-6 Torr pressure. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis has been carried out for phase analysis, microstructural investigation and elemental composition analysis. The adhesive strength of the metallizing layer and brazing strength of the joint have been measured by pull down breaking strength method. SEM study has shown that the width of the interfacial reaction region between the metallizing layer and substrate enhances with increasing the impurity content in the alumina ceramics. It has been observed that the adhesive strength of the metallizing layer depends on the interfacial reaction layer thickness. The adhesive strength of the metallizing layer has been increased with increasing the thickness of interfacial reaction layer. High adhesive strength of the metallizing layer as well as brazing strength has beenachieved for alumina ceramics with high impurity content.

9 illus, 1 table, 21 ref

041292   DEHKORDI Y G, ANARAKI A P, SHAHANI A R (Mechanical Engineering Dep, Shahid Rajaee Teacher Training Univ, Tehran 16758 136, Iran, Email: ali_pourkamali@sru.ac.ir) : Investigation of the effective parameters on welding residual stress in GTAW of aluminum cylindrical shell. Indian J Eng Mater Sci 2020, 27(1), 77-86.

The present work aims to study the influence of different geometrical, technological, and material parameters on residual stress in tungsten inert gas butt-welded aluminum cylinder. In order to present a simple analytical model to estimate the welding residual stress, the Taguchi L18 array has been employed with one 6-level factor and four 3-level factors. A 3D coupled thermo-mechanical finite element model considering temperature-dependent material properties has been developed to determine the welding residual stress in all experiments. The numerical model has been validated using the hole-drilling method. Using statistical analysis, the order of factors based on their effect on residual stress has been determined as yield strength, length, thickness, heat input, and finally diameter. The residual stress increases with an increase in yield strength, diameter, and heat input, while decreases with an increase in thickness. Contribution of each parameter on residual stress has been specified using variance analysis; yield strength with 99.6 % contribution is the most significant factor, while diameter has insignificant impact. Finally, high accuracy equations have been proposed to calculate the welding residual stress.

13 illus, 7 tables, 36 ref

041291   SUBRAMANIAN N, SOLAIYAN E (Vellore Institute of Technology, Chennai - 600 127, Email: naga.jothis2014phd1138@vit.ac.in) : GGBFS & M-sand impact on workability and strength properties of fly-ash based geopolymer concrete. Indian J Eng Mater Sci 2020, 27(1), 67-76.

This study involves the application of replacement material to cement which eliminates the carbon-dioxide emissions. Cement production industries alone give out 5 to 8 % of greenhouse gas into the atmosphere globally. Naturally, geopolymer concrete emits very low greenhouse gas compared to ordinary portland cement (OPC). Therefore, geopolymer concrete is greatly ecological and alternative material for OPC. This research has been intended to study the impact on workability and mechanical properties of fly ash based geopolymer concrete using ground granulated blast furnace slag (GGBFS) along with manufactured sand (M-Sand) under ambient curing condition. The work has been executed to explore compressive strength of G30 grade geopolymer concrete along with split tensile, flexural strength and its workability. The result shows that there has been increased strength and decreased workability with higher GGBFS & M-sand. Further, it shows the optimum percentage replacement of 20 % of GGBFS & 50 % of M-sand has been yielded G30 grade geopolymer concrete easily. Based on the investigation, better strength has been achieved by full replacement of natural sand with M-sand. Statistical analysis such as simple linear & multi variables regression has been carried out and formulas have been anticipated to find relationship between the mechanical properties of geopolymer concrete while increasing percentage of GGBFS.

8 illus, 4 tables, 41 ref

041289   MOONA G, WALIA R S, RASTOGI V, SHARMA R (Delhi Technological Univ, New Delhi - 110 042, Email: moonag@nplindia.org) : Tribological characterization of eco-designed aluminium hybrid metal matrix composites. Indian J Eng Mater Sci 2020, 27(1), 47-57.

In present experimental investigation, wear characteristics of Al 7075-T6/Eggshell/SiC/Al₂O₃ hybrid composites (Al 7075-T6 as base metal with eggshell particles wt. % 0.5, 1and 1.5, average particle size ~ 60 µm, SiC particles wt. % 1, 1.5 and 2, average particle size ~ 65 µm and Al₂O₃ particles wt. % 1.5, 2 and 2.5, average particle size ~90 µm) synthesized through electromagnetic stir casting route have been studied at various specimen temperatures under dry and lubricated test conditions. Wear investigations have been conducted on pin-on-disk rotary tribometer at a constant load of 20 N for a sliding speed of 2m/s and sliding distance of 2 km. Tribological attributes of synthesized composites have been evaluated as the function of reinforcements content and mechanical stirring time, as per the design of experiment according to Taguchi L9 orthogonal array. Experimental study has shown that at 30 ^ºC pin temperature under dry wear condition, among the developed hybrid composites, specimen S8 demonstrated a maximum relative decrease of 60 % in wear loss while with lubrication the wear loss has been relatively decreased by 89 % as compared to the base metal (specimen S0). At elevated pin temperature of 70 ^ºC under dry wear condition, the hybrid composite specimen S8 exhibited maximum relative reduction of 82 % in wear loss whereas under lubricated condition the wear loss has been relatively reduced by 82 % in comparison of their unreinforced counterpart (specimen S0). With exceedingly augmented tribological attributes, the current study strongly rationalizes high temperature wear resistant applications of synthesized aluminium hybrid composites with a total reinforcement weight percentage of 4.5 % only (specimen S8). 

25 illus, 4 tables, 19 ref

041287   BALASUBRAMANIAM V, RAJKUMAR D, RANJITHKUMAR P, NARAYANAN C S (Mechanical Engineering Dep, M.A.M. School of Engineering, Trichy - 621 105, Email: profdrajkumar@gmail.com) : Comparative study of mechanical technologies over laser technology for drilling carbon fiber reinforced polymer materials. Indian J Eng Mater Sci 2020, 27(1), 19-32.

More researchers have been worked to increase the quality of the machined composite materials. In this paper, a comparative experimental study of mechanical techniques over the laser techniques has been performed in the drilling process by using the carbon fiber reinforced polymer (CFRP). In order to identify the best process among the mechanical drilling (MD) and laser drilling (LD) technology various analysis methods like normality analysis, control chart analysis, and process capability analysis have been performed. Process capability index analysis for case study 1 and interval plot analysis for case study 2 have been employed to evaluate the best process comparatively. Experiments have been performed in a vertical machining center (VMC) and CO₂ laser. The final results revealed that the MD process is the best technology for drilling CFRP. Therefore, this work has been important for small-scale industries.

15 illus, 7 tables, 23 ref

041286   NIKOLOVA M, NIKOLOV D, YANKOV E, DERIN B, TOPALSKI S (Material Science and Technology Dep, Ruse A. Kanchev Univ, Studentska Str., 7017 Ruse, Bulgari, Email: mpnikolova@uni-ruse.bg) : Vacuum Oxy-nitro carburizing of tool steels: Structure and mechanical reliability. Indian J Eng Mater Sci 2020, 27(1), 5-18.

AISI H10, H11, H21, and D2 have been vacuum oxy-nitrocarburizing at 570 °C in cycling gas flow manner. Metastable diagram calculations belonging to Fe-N-C and Fe-N-C-X systems (X = Cr, Mo, W), have been performed by using “phase diagram” module of FactSageto predict the steels’ phase compositions. The reactive diffusion of both N and C into the tempered martensite has been discussed on the base of different chemical composition, size, and distribution of phases in the microstructure. The compound layers consisted mainly of not pre-saturated and poreless ε-carbonitride and magnetite (Fe₃O₄). In D2 steel, nitrogen diffusion caused a complete transformation of the primary carbides in 50 μm depths from the surface affecting the growth of grain boundary carbides. In contrast to the sharp compound/diffusion layer interface of H10, H11, and D2 steels, in H21 carbon and nitrogen were deeply absorbed in the diffusion layer while chromium strongly increased underneath the surface. The vacuum process enhanced the hardness and decreased the friction coefficients down to 0.13-0.15 at 100 N normal load for all samples. Since the compound layer thickness was relatively small for all tool steels, the phase composition and structure of the diffusion layers were found to be crucial for the scratch wear performance.

12 illus, 4 tables, 30 ref

041240   PENTEADO M M, TRIBST J P M, PIVA A M D O D, ARCHANGELO K C, BOTTINO M A, BORGES A L S (Dental Materials and Prosthodontics Dep, São Paulo State Univ, SP - 12245000, Brazil, Email: amodalpiva@gmail.com) : Influence of different restorative material and cement on the stress distribution of ceramic veneer in upper central incisor. Indian J Dent Res 2020, 31(2), 236-40.

Considering new ceramic systems, doubts about the appropriate combination of ceramics and cement are common. To evaluate the influence of the elastic modulus (E) of cement agents associated with different indirect veneers on the stress distribution using finite element analysis. The finite element analysis was applied to evaluate the stress distribution on the structures. For that, a computer‑aided design software was used for a three‑dimensional (3D) modeling of an upper central incisor with preparation for an indirect veneer. The model was imported into the analysis software in STEP (Standard for Exchange of Product data) format. Tetrahedral elements formed the mesh. Solids were considered isotropic, linearly elastic, homogeneous, and with ideal contacts. Load application (100N, 45°) occurred on the lingual face. Cement agents have their E classified as low, intermediate, and high. The ceramic materials used were a hybrid ceramic, a zirconia reinforced lithium silicate and a lithium disilicate. It was observed that none of the factors significantly influenced the stress concentration in dentine. Groups with high E cementing agent showed the highest stress peaks. The E of restorative material was significant for the stress generated in the veneer, and groups with hybrid ceramic presented more homogeneous stress results. The higher E of the cement agent and the ceramic, the higher the stress concentration, suggesting that hybrid ceramic associated with low elastic modulus resinous cement has superior biomechanical behavior.

3 illus, 1 table, 38 ref

042947   RAJENDRAN D K, RAJAGOPAL V, ALAGUMANIAN S, KUMAR T S, PRABHAKARAN S P S, KASILINGAM D (Mechanical Engineering Dep, National Institute of Technology Goa, Goa, Email: varthini.jaku@gmail.com) : Systematic literature review on novel corona virus SARS-CoV-2: a threat to human era. Indian J Virol 2020, 31(2), 161–73.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the seventh-generation coronavirus family causing viral pandemic coronavirus disease (COVID-19) across globe affecting millions of people. The objectives of this study are to (1) identify the major research themes in COVID-19 literature, (2) determine the origin, symptoms and modes of transmission of COVID, (3) recommend the intervention and mitigation strategies adopted by the Governments globally against the spread of COVID-19 and the traumatization among the public? and (4) study the possible drugs/treatment plans against COVID-19. A systematic literature review and comprehensive analysis of 38 research articles on COVID-19 are conducted. An integrated Research focus parallel-ship network and keyword co-occurrence analysis are carried out to visualize the three research concepts in COVID-19 literature. Some of our observations include: (1) as SARSCoV-2’s RNA matches * 96 % to SARS-CoV, it is assumed to be transmitted from the bats. (2) The common symptoms are high fever, dry cough, fatigue, sputum production, shortness of breath, diarrhoea etc. (3) A lockdown across 180 affected counties for more than a month with social-distancing and the precautions taken in SARS and MERS are recommended by the Governments. (4) Researchers’ claim that nutrition and immunity enhancers and treatment plans such as arbidol, lopinavir/ritonavir, convalescent plasma and mesenchymal stem cells and drugs including remdesivir, hydroxychloroquine, azithromycin and favipiravir are effective against COVID-19. This complied report serves as guide to help the administrators, researchers and the medical officers to adopt recommended intervention strategies and the optimal treatment/drug against COVID-19.

8 illus, 4 tables, 49 ref

042918   SHYAM P , MOHAMMAD M S (Biotechnology Dep, National Institute of Technology, Warangal, Telangana, Email: shyamperugu@nitw.ac.in) : A review analysis of insomnia: Age, gender, career, and efficient behavior methods perspectives. Indian J Sleep Med 2020, 15(2), 26–9.

Insomnia is one of the sleep disorders. Most of the people neglect the symptoms of insomnia. Our aim is to analyze an overall all together at one-step review of defining insomnia, types of insomnia, symptoms of insomnia, other diseases relating to insomnia, factors, diagnosis, and treatments of insomnia is performed for the scope of innovative method for solving the problem. Literatures were reviewed to analyze the insomnia statistically in terms of gender, age, and career. It is observed that women at their postmenopause state are the most prone to insomnia, and the rate of insomnia is high in elderly people. Working at stress, noise, nighttime, and family work imbalance was having impact. Factors indicating insomnia, effect of insomnia in other diseases as circadian rhythm disturbances, diabetes, and breast cancer were observed. The pathways involved, protein involved were analyzed, and it was observed as melatonin plays a key role in the inhibition of sleep induction. Treatments available are explored and enriched treatment with less side effects and good efficacy is needed.

2 illus, 24 ref

042901   SAREMI P (Transport Systems Dep, Engineering Sapienza Univ, Italy) : The role of the transportation system in the development of the tourism industry in developing countries. Indian J Sci Res 2020, 11(1), 61-75.

Today, tourism is one of the most important tools for economic growth and foreign Currency absorption for developing countries. Different countries around the world are taking various steps to advance their tourism industry, thereby boosting economic growth and job creation. Tourism is also a source of nutrition in the economy and is considered as economic stimulus. The tourism industry is expanding rapidly and this industry has become one of the largest businesses in the world. The Bright horizons, new destinations, new groups of tourists and developing types of tourism all and all promise the expansion of this industry. Also, the tourism industry is the result of travel and people's stay outside in their normal environment. Tourism is essentially achieved by moving people from their place of origin and permanent residence to faraway places. The development and expansion of the tourism industry depends on the development of transportation facilities. Infrastructure is important in the development of tourism, especially tourism transportation development has a major impact on growth of this industry. Providing appropriate, convenient and fast, safe, secure and affordable transportation is a prerequisite for tourism advancement because tourists consider two factors in their decisions, cost and time, and to access tourist destinations, choosing the type of transportation system or providing the right system affects these two factors. Tourism in developing countries is a major industry that contributes significantly to the national income both from local and international tourism. Transportation is a key element in developing the economy of these countries. Transportation advancement plays a crucial role in tourism development and sustainability worldwide and in developing countries. This paper focuses, assessing the existing transportation system conditions and their contribution to a sustainable tourism industry in developing countries. Results indicated that major modifications to the existing transportation system are needed to achieve a sustainable tourism industry in these countries. Tourism planning in developing countries should take into consideration the physical system of transport as a major component of the tourism development master plan. The purpose of this study is to investigate the development of transportation and its effects on the tourism industry and the research method is descriptive and review based study. The findings of this study can be key to the importance of tourism industry for the country's economy and the need to pay attention to the role of transportation in air, road, sea and its impact on tourism and tourism industry. The findings of this study show the key importance of the tourism industry for the country's economy and the need to pay attention to the role of transportation in air, land, water and communication lines and its impact on tourism and tourism industry.

32 ref

042899   JALALI M, SAREMI P (Industrial Engineering Dep, Asrrar Higher Education Institute, Mashhad, Iran) : A study on the impact of energy conversion technologies on food waste from macromolecules on the environment. Indian J Sci Res 2020, 11(1), 45-56.

Now days declining resources, increasing consumption, and inaccurate in energy consumption have led to global environmental crises. One of the best solutions is to use alternative fuels. Food waste can be used to supply alternative fuels. These wastes have degradable organic materials, which their releasing into the environment into the environment can cause many problems. The three major macro molecules in food, i.e. sugars, lipids, and proteins, can influence the production of clean energy through conversion processes. Starch, cellulose, hemicellulose and pectin from sugars, fatty acids from lipids and released amino acids from protein can be used from suitable raw materials in food processing to produce energy. Biogas, bioethanol and biodiesel energy processes are performed by anaerobic digestion, fermentation and chemical conversion processes, respectively. Food processing lines use a lot of energy to convert raw materials into final products, so the food industry is one of the seven most energy consuming industries. In this industry, in addition to high energy consumption, a large amount of solid and liquid waste is also produced. These wastes mainly contain biodegradable organic materials, the discharge of which causes significant environmental problems in the environment. Normally, a large amount of food waste is buried in a landfill, but liquid waste is dumped into rivers, lakes or oceans, or discharged into sewage. Recently, strict environmental regulations have severely restricted the discharge of solid and liquid wastes from food processing into the environment. Therefore, the disposal of these wastes is one of the major problems in the food industry, increased fuel prices and high energy consumption costs in the food industry, has strengthened the use of waste from these industries to produce cheap and clean energy in the form of biodiesel, biogas, bio-oils and synthetic gases. This article reviews the most important methods of converting waste and food waste into various forms of Energy and the impact of energy conversion technologies from waste of food macromolecules on the environment.

7 illus, 21 ref

042869   LAKSHMI E, MADHU G (Safety and Chemical Engineering Dep, Cochin Univ of Science and Technology, Kerala) : Evaluation and modelling of dissolved oxygen and re-aeration rate in river Periyar, South India. Indian J Sci Res 2020, 10 (2), 1-14.

Fresh water resources are one of the important resources for protecting and sustaining life on earth. Conservation of these resources has become an important priority for any nation to survive and progress. Rivers around the world are very much polluted and stressed of overuse. Adequate amount of dissolved oxygen is very much important for the growth of aquatic life and overall health of the river. Management of dissolved oxygen in the river requires long term continuous and scientific assessment. Modelling dissolved oxygen in the river and forecasting the future trend will support in understanding the characteristics of the river which further will help in planning management strategies. Periyar river is one of the most polluted rivers in Kerala, South India. River is abused by discharges from industries along the Eloor-Edayar stretch. Statistical evaluation using linear regression analysis and QUAL2K software was used for modelling dissolved oxygen in the river. Dissolved oxygen was predicted for year 2030 using WEAP water quality model. Models were calibrated using 2008 and 2013 data. Re-aeration rate of the river was also evaluated and its change with increasing surface water temperature. From the dissolved oxygen model developed using statistics and QUAL2K, it was found that both models can be used for modelling and prediction of variables in Periyar river. With the rising temperature, the re-aeration rate in the river was found to increase. The results from the paper could be used for planning management strategies for the river with the changing climate scenario.

4 illus, 8 tables, 100 ref

042868   LUCKY , ARYA H (Mechanical Engineering Dep, SLIET Longowal, Punjab -148 106, Email: luckysaklani94@gmail.com) : Improvement of low temperature impact toughness through flux modification for submerged arc welded low carbon steel E350 plates. Indian J Sci Technol 2020, 13(25), 2582–92.

To analyse the effects of rutile (TiO₂) and Alumina (Al₂O₃) on impact toughness properties of Submerged arc welded joints for low temperature applications. Al₂O₃ and TiO₂ have been added to F7AZ/PZ-EL8 Submerged arc welding (SAW) flux in varying quantities and the base material used for joining is low carbon structural steel having E350 grade. To verify the effect of these elements by flux modification, the Charpy V-Notch impact tests, scanning electron microscope (SEM) fractography and visible light microscopy (VLM) have been conducted. Charpy V-Notch impact testing and analysis have shown that there is considerable improvement in the impact properties of welds with the addition of 20 % TiO₂ and 20 % Al₂O₃ in the 80 % of flux as separate constituents i.e., when these elements have been added in the flux in separate form or two new modified fluxes were prepared, where one is doped with alumina and other is with rutile. Fractography of welds with addition of 20 % alumina in 80 % F7AZ/PZ-EL8 SAW fluxes are having best impact properties at lower temperature and addition of 20 % rutile also as almost effective as alumina in flux. consequently, mode of failure is ductile fracture with dimples as a result of good amount of acicular ferrite microstructure. Analysis of previous studies implicated that there is lack of significant studies in the low temperature impact properties of low carbon steel submerged arc welds. Present study shows that the significant improvement in the toughness properties of welds at lower temperature of -40 ^◦C can be achieved through flux modification, it would ensure the application of Low carbon steel structures at lower working temperature. The applications may be pressure vessels, ships or containers.

9 illus, 6 tables, 13 ref

042858   MEENA S (Civil Engineering Dep, Jai Narain Vyas Univ, Jodhpur - 342 011, Rajasthan, Email: sanu.iitb@gmail.com) : Impact of novel Coronavirus (COVID-19) pandemic on travel pattern: A case study of India. Indian J Sci Technol 2020, 13(24), 2491–501.

The outbreak of coronavirus disease 2019 (COVID-19) has been declared a pandemic by the World Health Organisation (WHO). The outbreak not only affects human health but also travel psychology. In order to understand the impact of coronavirus on the travel pattern of Indian people, this study adopts descriptive research techniques to compare travel scenarios during the normal situation, pre-lockdown, and till the COVID-19 pandemic end. The questionnaire included the information for socio-demographic characteristics of the respondents, travel pattern during the normal situation, pre-lockdown and post-lockdown period. The respondent has to perceive the post-lockdown situation and give their responses accordingly. The questionnaire also has some policy-related questions on the five-point Likert scale. The results of this study are based on online survey responses from 3148 individuals. It is observed that during the prelockdown period, people are more dependent upon the personal mode of transportation and the use of shared mobility dropped (35 % compare to the normal situation) significantly because of the high risk of virus transformation from close contact with unknown people and it is expected that, after the end of lockdown period, people will reduce their non-mandatory trips and higher income group will try to avoid travelling in public transport, taxi and other mass transport. This pandemic situation shows us the advantage of walk and bicycle (22 % of growth was observed during pre-lockdown), as these modes provides a great way to stay healthy and also an efficient way to support social distancing and reduce the load on public transport. The high percentage of uses of private vehicle (like cars and two-wheeler) will increase congestion on roads and it will lead to more air pollution. The findings of this study will help transport planner and policymakers to plan effective policy strategies to facilitate smooth transportation service during this pandemic situation. The author also recommend the public transport systems to come up with technological upgradation to reduce the contacts in terms of vehicular space (seat arrangements) and automated ticketing and overcrowd warning signals.

11 illus, 4 tables, 8 ref

042847   ISLAM T, KARIM M R , CHAION M H , DUTTA S , HOSSAIN M A (Textile Engineering Dep, Jashore Univ of Science and Technology, Jashore - 7408, Bangladesh, Email: mti@just.edu.bd) : Effect of chemical dosing amount in conventional cotton fabric pretreatment process. Indian J Sci Technol 2020, 13(23), 2345–54.

The objective of the study is to analysis the effect of chemicals on different physical properties and color fastness of treated cotton samples with standard rating values. Five single baths are used for the pretreatment process with five different dosages such as 1g/L, 1.5 g/L, 2 g/L, 2.5 g/L, 3 g/L of NaOH and H₂O₂. After that, reactive dyeing was performed for these five samples with a standard recipe. With the gradual increment of NaOH and H₂O₂ dosages, the absorbency and whiteness index of pretreated samples were improved and for that particular reason bursting strength was degraded. On the other hand, for dyed samples, a little variation was observed in color fastness to wash and rubbing but the changes in the color shade of every sample were observable.

9 illus, 7 tables, 13 ref

042846   MAHAPATRA P, ARORA G , AGGARWAL M , SINGH S , MANOCHA R (Mechanical Engineering Dep, Manav Rachna Univ, Faridabad, Email: prateekmh03@gmail.com) : Impact behaviour analysis of a newly designed go-kart chassis. Indian J Sci Technol 2020, 13(23), 2336–44.

The main objective of this study is to propose a new design of go-kart chassis and to assess the ability to bear the front, rear and side impacts on this proposed design. Another goal of this study is to make this design with different materials and also to test them in different loading conditions. To determine the safest material for the proposed Go-Kart chassis design based on the results obtained. A new and lighter go-kart chassis model is proposed in this study. A 3D go-kart chassis was modelled and its Finite Element Analysis was carried out on Autodesk fusion 360 software. Global test standards were used to simulate the impact behavior on go-kart chassis. In addition, this Go-kart chassis design was also made from three different materials i.e., AISI-4130, Al-6061 and CFRP composite. These Go-kart chassis were tested under different loading conditions. A comparative study of the obtained results was also carried out. The results of simulations performed under different conditions, showed this design has demonstrated adequate resistance against deformation in front, back and side impact tests. In every situation, factor of safety was more than one. Therefore, it can be inferred that the proposed design was completely safe under testing conditions. Under different loading conditions, the design made up of CFRP composite was safest among all the materials used. However, detailed modelling and simulation studies are needed before testing it in real-life conditions. Go-kart type of small vehicles are primarily used for recreational and racing purposes which are mainly powered by batteries as well as low capacity engines. The lower weight and better design of the chassis have the ability to improve their performance to a great extent. 

4 illus, 6 tables, 8 ref

042838   MEMON M A, BHUTTO G M , BURIRO E A (Electrical Engineering Dep, Quaid-e-Awam Univ of Engineering, Pakistan 67480, Email: engr.mam@quest.edu.pk) : Sizing of dc-link capacitor for a grid connected solar photovoltaic inverter. Indian J Sci Technol 2020, 13(22), 2272–81.

To determine the optimum size of a dc-link capacitor for a grid connected photovoltaic inverter. Dc-link capacitors are considered as one of the sensitive parts of the grid connected photovoltaic systems and needs effort to design a reliable and optimal size capacitor as its reliability is concerned with the overall system reliability. The double line frequency power flows between the input and outside of a Φ grid connected PV system which produces voltage ripples at the capacitor and dc link. This voltage ripple increases temperature of passive components and dc source which affects the MPP operation of the photovoltaic modules and the system life. Therefore, it is essential to limit the voltage ripples at the input side of the system. The easiest way to limit the double frequency ripple voltage is to connect a capacitor in parallel to the PV module and the inverter which buffers the double line frequency power and supply a constant power to the inverter. This study proposed a general method for sizing a dc-link capacitor for a Φ grid connected voltage source inverter. It is seen that the capacitance is inversely proportional to the nominal dc and ripple voltage. Thus an increase in the nominal system voltage decreases the size of the capacitor and at the same time increases the voltage ripple. Therefore to limit voltage ripple within permissible limits and to ensure better system performance the dc-link capacitor must be appropriately sized. The simulations based on 3kW grid connected PV system are carried out in DIgSILENT Power Factory software. A capacitor of 410µF is needed to be connected in parallel with a 3kVA inverter having an nominal input voltage of 370V and maintaining a voltage ripple under 8.5 %. Novelty: After determining optimized dc-link capacitor size we will limit the voltage ripple under permissible limits and hence improves the system efficiency and life of the grid connected PV system.

6 illus, 4 tables, 30 ref

042836   CHAI M K, TAN Y H , WONG L S (Engineering Dep, Tenaga Nasional Univ, Kajang, 43000, Selangor, Malaysia, Email: mkchai@uniten.edu.my) : Macronutrient effect on biomass of microalgae in biofuel production: A review. Indian J Sci Technol 2020, 13(22), 2245–63.

This review is focused on the effect of macronutrients (nitrogen, carbon and phosphorus) on biomass production of microalgae especially concerned with biofuel. The keyword search included "microalgae cultivation", "nitrogen sources", "phosphorus sources", "organic carbon", "biodiesel", "biofuel", "carbon dioxide", "inorganic carbon", "macronutrient deprivation", "macronutrient limitation", "lipid" and "organic waste" to search the published journals in ScienceDirect, Scopus, Springer, and Google Scholar. The search was performed from December 2019 until Mac 2020 to collect all the journals and books that are published between 2006 and 2020. The effect of each macronutrient (nitrogen, carbon and phosphorus) on microalgal growth of the control and the samples were compared using biomass productivity, concentration and biochemical content in each published article. Review shows that nitrogen has more pernicious effect than other macronutrients on most microalgal growth and lipid production. The concentrations and types of macronutrients have remarkable effects on the growth of microalgae; hence these criteria must be chosen scrupulously to achieve the desired biomass and metabolite production. In order to improve the biomass and biochemical productivity in concomitant with the cost reduction, replacement of cheap organic waste, genetic engineering of microalgae and two-stage hybrid system have been suggested to simultaneously maximize the biomass and biochemical production. The future research should focus on other biochemical contents such as carbohydrates, proteins and pigment to achieve the biorefinery context which can increase the profit. Besides, economic factor such as factorial design should be included in the future research to obtain the best combined factors with the maximum profit and minimal cost.

2 illus, 3 tables, 124 ref

044826   SINGH P, GEORGE P J, RAMTWEKE P W, PAUL A (Molecular and Cellular Engineering Dep, Sam Higginbottom Univ of Agriculture, Allahabad, Uttar Pradesh) : Performance of Bollgard I with different plant spacing and in presence of refuge crops. J Pharmacogn Phytochem 2020, 9(2), 78-81.

Different biotic and abiotic factors affect the growth and yield of Bt cotton. Appropriate agronomic practices like plant density and presence of refuge crops have profound effect on the development and final outcome of the crop. A field experiment was conducted to assess the performance of Bollgard I variety (cotton 1007-9810 BGI) of Bt cotton under different plant spacing (30 x 30 cm, 60 x 60 cm and 80 x 80 cm) and in presence of 50% refuge nBt cotton (cotton Mahesh) which is a different cultivar, at Horticulture Research Farm, Department of Horticulture, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad (Uttar Pradesh). It was noted that plant height was found significantly higher in closer spacing whereas monopodial branches plant-1 (1.73, 1.60), sympodial branches plant-1 (16.66, 12.33), bolls plant-1 (20.33, 17.44), average boll weight plant-1 (3.30, 3.23), seeds plant-1 (452.99, 411.66) and lint weight (g) plant-1 (17.61, 14.02) were recorded higher in 80 x 80 cm followed by 60 x 60 cm, and 30 x 30 cm. Comparison of Bt yield attributes with refuge nBt from the field trial containing 50 % refuge nBt cotton recorded maximum yield attributes in Bt cotton.

2 tables, 21 ref

042821   VARSHINI A G P, KUMARI K A (Dr.Mahalingam Coll of Engineering and Technology, Pollachi, Coimbatore, Email: priyavarshini.a.g@gmail.com) : Predictive analytics approaches for software effort estimation: A review. Indian J Sci Technol 2020, 13(21), 2094–103.

In Software Effort Estimation (SEE), predicting the amount of time taken in human hours or months for software development is considered as a cumbersome process. SEE consists of both Software Development Effort Estimation (SDEE) and Software Maintenance Effort Estimation (SMEE). Over estimation or under estimation of software effort results in project cancellation or project failure. The objective of this study is to identify the best performing model for software Effort Estimation through experimental comparison with various Machine learning algorithms. Software Effort Estimation was addressed by using various machine learning techniques such as Multilinear Regression, Ridge Regression, Lasso Regression, ElasticNet Regression, Random Forest, Support Vector Machine, Decision Tree and NeuralNet to recognize best performing model. Datasets used are Desharnais, Maxwell, China and Albrecht datasets. Evaluation metrics considered are Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Square Error (RMSE) and R-Squared. Experiments on various machine learning algorithms for software Effort Estimation determines that Support Vector Machine produced the best performance comparatively with other algorithms.

4 illus, 6 tables, 28 ref

042818   KHAN M A, KHAN M Z , KHAN H , HANZLA M , JAMAL M , KHALID T , ULLAH N (Electrical Engineering Dep, FICT, BUITEMS, Quetta, Pakistan, Email: engineerabbaskhan111@gmail.com) : Garbage collector robot. Indian J Sci Technol 2020, 13(20), 2065–70.

The primary aim is to introduce a way in which garbage could be collected and disposed efficiently; To analyze the problem of garbage disposal at a school, restaurant, office, hotel, production plant or any other suitable location; To design and develop a system for solving the problem; To test and maintain the implemented system. Our project is divided into two main parts. We are designing a system that collects garbage automatically through line. For which we are designing an arena so that the machine will follow the specific path and also manually by using Arduino and Bluetooth module. The machine can be controlled by software which will give command to the robotic jaw to collect the stationary waste. It also has the characteristic to get controlled by voice command which makes the robot to collect the garbage according to the given command. We have designed a semi-autonomous garbage collector robot which can do multiple functions. This robot has one robotic arm in which it can pick the garbage and dispense it in main basket attached to the robot. The camera placed on robot helps the administrator to remotely monitor the robot while collecting garbage. The prototype has an electronic mechanism by which the robot can dispense it collected garbage to the dispensing point. This robot has installed batteries in which there is no fuel or electricity required to complete the operation.

3 illus, 1 table, 8 ref

042812   AKTER N , REPON M R, RASHID M A , SHIDDIQUE M N A (Textile Engineering Dep, Khwaja Yunus Ali Univ, Sirajganj, Bangladesh, Email: reazmbstu.te@gmail.com) : Performance analysis of spandex incorporated single jersey fabrics for sportswear. Indian J Sci Technol 2020, 13(20), 1998–2009.

The main objective of this study is to substantiate the effects of spandex on the properties of plain jersey fabric as compared to the commercial knit sports wear. Three single jersey plain knitted fabric samples were produced with full feeder spandex (4.45%), half feeder spandex (2.22 %), and without spandex. 34/1 Ne cotton yarn and 20D spandex were used. Standard test methods were followed to analyze the fabric properties. ASTM D 3774: 2004, ISO 6330:2012, ISO 12945-2, ISO 12947-1:1998 and ISO 13938- 1:1999 methods were used to measure the variation between cotton and cotton/spandex plain jersey fabric, different physical properties in particular GSM, width, abrasion resistance, pilling, bursting strength, and shrinkage of the specimens. The physical, dimensional, and mechanical properties of cotton/spandex plain jersey knitted fabrics were investigated. The results were compared between knitted fabrics made from 100 % cotton and spandex with cotton. The effect of spandex percentage was also studied. A significant effect was observed on the physical, dimensional, and mechanical behaviors of single jersey fabric. Results revealed that the GSM, shrinkage, abrasion resistance, and bursting strength increased and the width reduced with the increased amount of spandex percentage. No apparent effect on the pilling resistance was observed. The manufactured spandex incorporated knitted fabrics can be found in a wide range of applications. The main endeavor is to use for active sportswear. 

11 illus, 7 tables, 21 ref

042810   RAMESHBABU R, SURESH G R (Electronics and Communication Engineering Dep, St. Peter's Institute of Higher Education and Research, Chennai, Tamil Nadu, Email: rrameshbabu15@gmail.com) : Design of adaptive feedback control for new 3D chaotic system and its digital implementation on FPGA. Indian J Sci Technol 2020, 13(20), 1977–90.

In this research work, digital circuit implementation on FPGA of an adaptive feedback control methodology for a new 3 – D chaotic system is proposed. The chaos synchronization is achieved using adaptive feedback control method. The new adaptive controllers are designed to achieve the chaos synchronization for the identical new chaotic system. The FPGA implementation of chaos synchronization using numerical methods induces artificial suppression in the chaotic system or chaotic behavior can be dead in very short-time. In this research work, the FPGA implementation of chaos synchronization is achieved with the help of automatic code generator like System generator in Matlab simulink. The adaptive feedback control for identical new chaotic system is coded with VHDL with 32 bit fixed point number, 12 for the entire and 20 for the fraction. In this paper, we designed a new 3D chaotic system and its chaotic behavior is verified using Lyapunov exponents, stability analysis and Poincare map. The complete synchronization for proposed chaotic system is achieved using adaptive feedback control methodology. The digital circuit realization of adaptive feedback control for the synchronization of identical chaotic system based on FPGA is achieved for the various applications of digital information systems. Simulation results and FPGA outputs illustrate the effectiveness of our proposed method. The digital implementation of adaptive feedback control has many engineering applications such as digital data transmission, digital modulation, video encryption, digital cryptosystem etc. 

11 illus, 2 tables, 39 ref

042809   RAVINDRA S, SIDDESH G K (Electronics and Communication Engineering Dep, Dayananda Sagar Coll of Engineering, K.S.Layout, Bengaluru, Email: ravindraece@dayanandasagar.edu) : System capacity evaluation for mobility management in LTE-advanced D2D networks. Indian J Sci Technol 2020, 13(20), 1965–76.

This study aims to evaluate the system capacity for mobility management in Long Term Evolution-Advanced (LTE-A) Device to Device (D2D) networks with suitable handover schemes. This paper introduces power control mechanisms for 5G based on the distance between D2D terminals. Interference is a major issue which reduces the performance of D2D communication. The proposed system introduces an algorithm based on greedy algorithmic approach for interference mitigation with easy handover for system capacity estimation. The implementation is carried out using LabVIEW platform and results are analyzed. The existing mobile communication approaches transfer calls through base stations irrespective of the distance between the mobile terminals. User mobility is an important factor for D2D communication and proper selection of mobility patterns that helps in increasing the energy efficiency and throughput by reducing interference. Efficient utilization of these mobility patterns are shown in the proposed method for developing an optimal time efficient mobility aware caching mechanism with lower complexity. In the recent works, less importance has been given for users' contact time duration while they are moving with different speeds. The simulation results show an enhancement in the system capacity of approximately 480 bits/Hz for 50 devices and 290 bits/Hz for 20 D2D users. The simulation results prove that the proposed approach gives better performance than the existing methods. 

11 illus, 1 table, 28 ref

044786   ARUNA S T, LATHA S, LAKSHMI R V (Surface Engineering Div, National Aerospace Laboratories, Bangalore- 560 017, Email: aruna_reddy@nal.res.in) : Multifunctional properties of electrodeposited nickel composite coating containing nanosized monoclinic zirconia particles. J Met Mater Sci 2020, 62(1-2), 77-91.

Nickel-based composite coatings containing ceramic particles as the distributed phase have been widely used in aerospace and automotive industries. In the present work, a Ni-composite coating containing nanosized monoclinic zirconia (ZrO2 ) powder is prepared by solution combustion (SC) method. The SC method is modified to get phase pure white zirconia powder by using the mixture of fuels approach. Since the synthesized powder contained agglomerated particles, the powder is ball milled and dispersed in a nickel sulphamate bath. The Ni and Ni-ZrO₂ coatings are electrodeposited at 0.75 A/dm² for 6 h. The Ni-ZrO₂ composite coating exhibits a microhardness of 750 KHN(50 gf) as against 270 KHN(50 gF) observed for plain Ni coating. The Ni-ZrO₂ coating exhibits improved corrosion resistance and wear resistance compared to plain nickel coating as confirmed by potentiodynamic polarization and continuous salt spray tests. The as-deposited hydrophobic Ni-ZrO₂ coating transforms to superhydrophobic upon depositing a thin layer of fluoroalkyl silane on the coating. Thus, the synthesized zirconia particles when incorporated in the Ni matrix impart multifunctional properties to the electrodeposited Ni coating.

10 illus, 6 tables, 37 ref

042803   ANITA JESSIE J , DANISH P, GANESH S , RAINA C S (Civil Engineering Dep, Model Institute of Engineering and Technology, Jammu -181 122, Jammu and Kashmir, Email: danish.civ@mietjammu.in) : Implementation of paper mill waste as partial replacement material. Indian J Sci Technol 2020, 13(19), 1901–7.

The objective of the study was to study the compressive strength of the partially replaced paper mill waste in cement. The concrete cube specimen were prepared for compressive strength test. In this study, the cement has been replaced with 20 %, 30 %, 40 % and 50 % of hypo sludge. The specimens were cured for two different ages (7 days and 28 days) and tested for compressive strength. The quadratic polynomial prediction equation was proposed using Response Surface Methodology (RSM). The prediction model was developed using the experimental output results. Thus, the prediction model facilitates the further research work to be conducted by researchers on paper mill waste replacement. The rate analysis was also further carried out to show the cost effectiveness of using the waste replacement in cement. The test was conducted on the compressive strength (7 days and 28 days) of control specimen (0 %) and partial replacement of 20 %, 30 %, 40 % and 50 % of cement using the hypo sludge. Thus, 20 % replacement of cement using hypo sludge has shown good compressive strength than the control specimen. The cost of 20 % paper mill waste was less when compared to the cost of control specimen. The compressive strength of 20 % partial replacement of paper mill waste in cement can be used in further construction. The prediction model can be used to predict the future compressive strength of partially replaced paper mill waste concrete.

6 illus, 4 tables, 12 ref

042800   BALAJI K, WESSLEY G J J (Aerospace Engineering Dep, Karunya Institute of Technology and Sciences, Coimbatore - 641 114, Tamil Nadu, Email: jims_john@karunya.edu) : Experimental investigations on the performance of a modified co-flow jet aerofoil. Indian J Sci Technol 2020, 13(19), 1873–81.

To study the performance of a Modified Co Flow Jet (MCFJ) aerofoil with a converging nozzle located at the leading edge so as to reduce the pumping power. The experimental investigations are conducted on a base aerofoil and a modified CFJ (MCFJ) aerofoil in a subsonic tunnel at various angle of attack (AOA). The output performance parameters like coefficient of Lift (CL), Coefficient of drag (CD) and Lift are obtained for both the aerofoil and the results are compared. The result shows that the stalling angle of the MCFJ aerofoil advanced by 5 ^◦ providing better flow characteristics than the baseline aerofoil. The lift increases up to 43 % during the critical angle of attack of 25 ^◦ in the MCFJ aerofoil. In the present study, a convergent nozzle is placed near the leading edge of the CFJ aerofoil which effectively controls the mass flow rate of the flow during all phases of flight, thereby resulting in improved aerodynamic performance. This novel concept can be used for improved aerodynamic performance of MCFJ aerofoil with reduced pumping power. Also, it is possible to obtain improved performance of CFJ Method at all phases of flight by controlling the flow velocity by using the convergent nozzle.

10 illus, 2 tables, 12 ref

044781   ANANTHAPADMANABHAN S S, MISHRA G, PARIDA S (Metallurgical Engineering and Materials Science Dep, Indian Institute of Technology, Mumbai, Email: paridasm@iitb.ac.in) : A brief review on the development of self-healing, hydrophobic and antifouling epoxy coating. J Met Mater Sci 2020, 62(1-2), 1-15.

Epoxy coatings are the most used industrial coating system. While corrosion resistance through the barrier performance of the coating is well tested, the addition of multifunctionality is the new research objective. The responsiveness of the epoxy coating to the mechanical damage will not only add to its barrier performance but also delay the corrosion of the underlying metal. Such responsiveness of the coating is desired to manage the maintenance schedule. Various methods tested to add the “self-healing” attribute to the epoxy coatings are discussed. Surface modification to add hydrophobic character to the epoxy coating is also another functionality for value addition and is useful in many applications. For marine applications, fouling resistance is very important. Attempts made to develop anti-fouling epoxy coating are also reviewed. The brief review, giving a broad overview of the research trend, is intended to give a way forward in the development of the epoxy coating.

3 illus, 58 ref

042792   MEHTA P , KUMAR S, PATEL V , JOSHI A (Mechanical Engineering Dep, Gujarat Power Engineering and Research Institute, Mehsana - 384 460, Gujarat, Email: sumit.kumar@gperi.ac.in) : Mathematical modeling and performance assessment of solar air collector. Indian J Sci Technol 2020, 13(18), 1803–10.

The use of solar air heater in drying has been increasing in recent years, because of their simplicity and economic configuration. Design and testing of the corrugated solar collector have been carried out in the present study. The overall system was designed and tested at Gujarat Power Engineering and Research Institute, Mehsana, India (GPERI, 23 ^◦31'37.4"N72 ^◦23'14.1"E). Exergetic efficiency, thermal efficiency, and temperature outlet at the same mass flow rate and solar irradiance were the major parameters for the present study. The designed system was tested by varying the mass flow rate of 0.1075, 0.215, and 0.3225 m³ /sec. It was found that the temperature of the corrugated collector was maximum at 92 ^◦C at solar radiation of 750 W/m² . Whereas thermal efficiency was found to be 65.10 % the same radiation. It was depicted from the tests that the corrugated plate performs more efficiently than a flat plate collector due to surface roughness. It is a good practice in a region where solar radiation is higher all year to implement this type of arrangement for the utilization of any solar gadget, and to enhance its performance efficiency. it can be observed that collector outlet temperature in the semi-arid region of Gujarat was maximum at the minimum collector area. This should be the best design and thermal performance in a semi-arid climate.

5 illus, 1 table, 21 ref

042780   KARIM M R, ISLAM T , DUTTA S, HOSSAIN A , BAIN S (Textile Engineering Dep, Port City International Univ, Chittagong - 4225, Bangladesh, Email: rk09006@gmail.com) : Reuse of dye effluents into the fresh batch dyeing with the variation of chemical and dye percentages. Indian J Sci Technol 2020, 13(16), 1693–701.

To study the reuse of dye effluents in order to minimize the dyeing cost. In this study, the exhausted dye effluents were reused into 7 new dyeing baths along with 7 different percentages of dyes and chemicals to evaluate the color fastness properties as well as shade difference. Firstly, the exhausted dye effluents were collected from the dye bath of the standard sample after dyeing was completed. Then respectively added extra 80 %, 70 %, 60 %, 50 %, 40 %, 20 % and 0 % of the dyes and chemicals in the 7 different new baths where dye effluents of standard sample dyeing existed. After dyeing, all the 7 samples were collected and tested with ISO methods for the assessment of color fastness to Wash and color fastness to Rubbing. Moreover, all the samples were analyzed against the standard one with the help of a Spectrophotometer. From the overall testing reports, it had found that color fastness to wash and rubbing were satisfactory for all samples. But the CMC decision revealed that the sample which was treated along with the presence of an extra 80 % dyes and chemicals in dye effluents showed minimum shade difference from the standard sample. So, it can be said that about 20 % of dyes and chemicals can be saved by reusing dye effluents which can largely influence not only the environmental issues but also the cost-effectiveness of dyeing industries.

1 illus, 13 tables, 18 ref

040987   ANANDAKUMAR, BABU B M, SATISHKUMAR U, REDDY G V S (Soil and Water Engineering Dep, Agricultural Engineering Coll, Raichur - 584 104, Karnataka, Email: anandk624@gmail.com) : Comparative study between wavelet artificial neural network (WANN) and artificial neural network (ANN) models for groundwater level forecasting. Indian J Agric Res 2020, 54(1), 27-34.

Groundwater level fluctuation modeling is a prime need for effective utilization and planning the conjunctive use in any basin.The application of Artificial Neural Network (ANN) and hybrid Wavelet ANN (WANN) models was investigated in predicting Groundwater level fluctuations. The RMSE of ANN model during calibration and validation were found to be 0.2868 and 0.3648 respectively, whereas for the WANN model the respective values were 0.1946 and 0.1695. Efficiencies during calibration and validation for ANN model were 0.8862 per cent and 0.8465 per cent respectively, whereas for WANN model were found to be much higher with the respective values of 0.9436 per cent and 0.9568 per cent indicating substantial improvement in the model performance. Hence hybrid ANN model is the promising tool to predict water table fluctuation as compared to ANN model.

15 illus, 2 tables, 12 ref

042773   KHAN M A, KHAN M Z , BAZAI S E , AHMED S O , KHAN H , EJAZ N , ULLAH N (Electrical Engineering Dep, FICT, BUITEMS, Pakistan, Email: engineerabbaskhan111@gmail.com) : Motion based smart assistant for visually impaired people. Indian J Sci Technol 2020, 13(16), 1612–8.

The present paper deals with building a smart assistant with the aim of assisting the visually impaired people in mobility with confidence by realizing the nearby obstacles and also implement image processing techniques to recognize people. We use Raspberry Pi 4 which has increased computing performance and is interfaced to the picamera, GPS and GSM modules. Arduino pro mini with buzzer, ultrasonic sensors and vibration motors are used for obstacle detection. Certain libraries important for image processing are used such as OpenCV, Dlib, face detection (Haar cascades, HOG + Linear SVM, or CNNs), espeak for converting text to speech. Programming was implemented through Python and Arduino compiler. Analysis was carried out using the proposed system for the blind and visually impaired people who could move around comfortably with confidence and were also able to detect objects and recognize people. Hence the proposed system removes the use for the cumbersome white cane in exchange for small and handy modules which can be used in the form of wearables mounted on shoulders, hands and legs to detect the obstacles from multiple directions and provide for a comfortable wear. It was determined that the Raspberry pi 4 was incapable of running CNN detection for which ideally computer GPU was required, so HOG detection method was used instead. This project can be implemented mainly in the commercial field of helping visually impaired people with poor eyesight or being completely blind. Industrial applications can be devised and enhanced like robots and machineries along with Security, Identifying and Tracking.

5 illus, 22 ref

042770   TAHA F F, HATEM W A , JASIM N A (Civil Engineering Dep, Diyala Univ, Diyala, Iraq, Email: aliraqiafarah320@gmail.com) : Adoption of BIM technology to develop sustainable buildings in the Iraqi construction sector. Indian J Sci Technol 2020, 13(15), 1596–606.

This study aims to identify and assess sustainable design parameters based on the tools and strategies provided by Building Information Modeling (BIM)technology to improve building sustainability. This study idea was applied to one of the Iraqi construction projects in Diyala province, to achieve the aim of this study, we collected real data (CAD drawings, schedule of quantities) by an interview with professional engineers in the construction fields and after this, the project is simulated by using Autodesk Revit 2018 software. We made analysis and found the results of analysis by using Autodesk Insight 360 Cloud added to Revit 2018 that illustrate design parameters and its effect on energy use intensity. The use of BIM technology helps designers and architects to identify and assess sustainable design parameters in the early design stage that lead to improving the sustainability of the building. BIM technology is one of the modern and important technologies in the construction sector. Adopting BIM technology is very useful to develop sustainable buildings in the construction sector.

14 illus, 19 ref

042765   ANI K A, THOMPSON O E , MIKE G R (Chemical Engineering Dep, Nnamdi Azikiwe Univ, Awka, 5025, Anambra, Nigeria, Email: anikingsley16@yahoo.com) : Kinetics of crude oil degradation by an indigenous mixed culture isolated from palm oil mill effluent. Indian J Sci Technol 2020, 13(15), 1555–62.

To investigate the microbial growth kinetics and degradation of crude oil (CO) by mixed cultures isolated from palm oil mill effluent (POME). The scanning electron microscope was employed to examine the surface morphology of POME and the CO contaminated soil. Microbial count using the total viable count (TVC), mold, and coliform counts were investigated at different levels of CO contamination. The TVCs at 20, 40, and 60 mg/L of CO were 7.3x107 CFU/g, 6.8x106 CFU/g and 7.2 x 106 CFU/g, respectively. The concentration of the CO was utilized at 20 mg/L indicating that this concentration did not inhibit microbial growth. Based on the correlation coefficient (R2 ) values obtained for the four growth kinetic models, the Haldane model with R2 of 0.97 gave the best fit. Finally, the one way ANOVA and Tukey's honest significant difference (HSD) indicated the statistically significant effect (P< 0.05) of the initial CO concentration on microbial growth.

4 illus, 6 tables, 27 ref