001008   GHANATI P, SAFAEI B (Mechanical Engineering Dep, Tsinghua Univ, Beijing 100084, China, Email: saf16@mails.tsinghua.edu.cn) : Elastic buckling analysis of polygonal thin sheets under compression. Indian J Phys 2019, 93(1), 47–52.

In this work, we have studied elastic buckling of regular hexagonal thin sheets made of homogeneous and isotropic materials under in-plane hydrostatic and uniaxial compression, with internal supports, translational and rotational elastic edge supports, and a combination of free, simple-support and clamped boundary conditions. An energy method called Rayleigh–Ritz was utilized and the kinematic hypotheses of the classical thin plate buckling theory were applied. Displacement conditions were applied to edges and internal supports by employing proper basic P-Ritz functions. This approach gives an approximate analytical response that was calculated with Maple software and validated by previous researches. Moreover, the results were compared to numerical results obtained from ANSYS software. The findings revealed that besides having the advantages of other analytical methods, the Rayleigh–Ritz method is easy to use and straightforward to apply different constraints on boundaries and internal points; however, increasing the number of edges and constraints adds significantly the burden of calculation.

4 illus, 3 tables, 28 ref

000991   BOUKORTT N, HADRI B (Electrical Engineering Dep, Kuwait Univ, 13060 Kuwait, Kuwait, Email: nboukortt@unime.it) : Bifacial n-PERC solar cell characterization. Indian J Phys 2019, 93(1), 33–9.

This paper investigates the outdoor bifacial n-type silicon passivated emitter rear cell (PERC) and the influence of the contact resistance and temperature dependence on the output properties by using Silvaco TCAD tools. PERC is considered as an effective solution to increase the energy yield and reduce the levelized costs of electricity in a real PV system. This paper presents a comparison between bifacial n-PERC and standard n-PERC cell technology. This investigation at 300 K leads to achieve the following results J_sc = 43.93 mA/cm², V_oc = 0.763 V, FF = 80.44 %, P_max = 269.77 W/m^-2 , and η = 26.97 % for AM1.5 spectra and with only 20 % albedo which are close to and improved with those found in different research works. This technology provides a better electrical control over the cell and thus leads to valuable improvements in photovoltaic devices performance.

9 illus, 3 tables, 41 ref

001006   GANDHI A, VELLAIYAN S, SUBRAMANIAN V S, SHANMUGAM T , MURUGESAN K, SUBRAMANIAN K (All India Institute of Medical Sciences, New Delhi - 110 029, Email: vsmani_arun@yahoo.com) : Commissioning of portal dosimetry using a novel method for flattening filter‑free photon beam in a nontrue beam linear accelerator. J Can Res Ther 2019, 15(1), 223-30.

The aim of this study is to commission and validate the portal dosimetry (PD) system using an indirect method for flattening filter free (FFF) photon beam of the upgraded c‑series linear accelerator. Varian Medical System clinacs with amorphous‑silicon portal imager panel (aSi‑1000) do not have PD for FFF beams. Recently, our c‑series linear accelerator was upgraded to deliver 6MV FFF (6MVFFF) photon beam with the highest dose rate of 1400 monitor unit (MU)/min. The study, therefore, focuses on the commissioning and validation of PD for the 6MVFFF beam. An indirect method was implemented to predict the portal dose for FFF beam in Eclipse as the treatment planning system does not have direct prediction algorithm for FFF beam (version. 11). Dosimetrical characteristics of aSi‑electronic portal imaging device (EPID) were evaluated for 6MVFFF beam and validation of PD for 6MVFFF beam was performed for open fields along with pretreatment quality assurance of intensity‑modulated radiation therapy(IMRT), volumetric‑modulated arc therapy(VMAT), and stereotactic radiosurgery (SRS) techniques for 30 patients planned with 6MVFFF beam. ASi‑EPID saturates between 100 and 130 cm source to detector distance (SDD) for 6MVFFF beam and resolved at more than 140 cm SDD. The squared correlation coefficient (R²) for MU linearity was found to be 1 (R² = 1), and instantaneous dose response linearity at different SDD’s was found to be 0.999 (R² = 0.999) for the 6MVFFF beam. Maximum gamma area index (GAI) for 3 % dose difference and 3 mm distance‑to‑agreement criteria for IMRT, VMAT, and SRS/stereotactic radiotherapy plans was 97.9% ± 0.3 %, 96.3 % ± 0.5 %, and 98.2 % ± 0.2 %, respectively. The results reveal that this novel method can be used to commission portal dosimetry for 6MVFFF beam as it is a convenient, faster, and accurate method.

8 illus, 1 table, 14 ref

001021   KARBAF M, YAZDI M H H, GHORBANI M, ABDOLLAHI S (Biomedical Engineering and Medical Physics Dep, Shahid Beheshti Univ of Medical Sciences, Tehran, Iran, Email: mhdghorbani@gmail.com) : Assessment of radiation leakage from treatment applicator of Siemens primus plus and siemens artiste linear accelerators. J Can Res Ther 2019, 15(1), 216-22.

The purpose of this study is to measure radiation leakage of Siemens Primus Plus and Siemens Artiste linear accelerators in electron mode and to compare the leakage level with that recommended by the International Electrotechnical Commission (IEC) standard. In this assessment, Siemens Primus Plus linear accelerator with 10 cm × 10 cm, 15 cm × 15 cm, and 25 cm × 25 cm applicators was used. The radiation leakage in lateral and vertical directions was measured for Siemens Primus Plus and Siemens Artiste linear accelerators. Data derived from radiation leakage measurement for Siemens Primus Plus and Siemens Artiste linear accelerators in lateral direction from the field edge and in vertical direction from the applicator were reported. The radiation leakage data were then compared with the IEC standard to evaluate in‑air field leakage. Comparing the radiation leakage level from fields with the IEC standard for two applicators, the maximum that was occurred for 12 MeV electron beam and applicator size of 10 cm × 10 cm in Siemens Artiste linear accelerator was 2.3%, which is less than the IEC’s recommended limit of 10 %. It is concluded that the leakage amount is much less than the specified limit and that both of the linear accelerators have high level of safety. Considering the measurement stage, it also needs to be noted that the beam angle affected the radiation leakage level from field edge, and in 25° angle, it is higher than in 0° angle. Comparing radiation leakage from the right side of the field for the two linear accelerators, the amount of leakage for Siemens Primus Plus linear accelerator is more than Siemens Artiste linear accelerator.

7 illus, 3 tables, 10 ref

001025   KESAVAIAH D C, REDDY K R, REDDY G P (Humanities & Science Dep, K G Reddy Coll of Engineering & Technology, Rangareddi- 501 504) : MHD rotating fluid past a moving vertical plate in the presence of chemical reaction. Int J Info Computing Sci 2019, 6(2), 142-54.

The present paper an analysis of MHD effects on unsteady free convection heat and mass transfer over a moving isothermal vertical plate in a rotating fluid in the presence of chemical reaction is presented. An exact solution is obtained for the axial and transverse components of the velocity by defining a complex velocity. The governing partial differential equations are solved by using perturbation technique. The effects of velocity, temperature and concentration profiles for different parameters on the plate are discussed with graphically by using Matlab.

9 illus, 2 tables, 12 ref

001011   GORANE P S, PANCHAL A C, PATIL G R, CHAVAN V R, LAVHE G Y (Mechanical Engineering Dep, G. S. MOZE COE, Pune, Maharashtra) : Power generation through bag. Int J Info Computing Sci 2019, 6(1), 123-9.

The need of today’s world is non-renewable source of energy which is available on earth. The need is increasing, to overcome this there is requirement of more energy source. Man has been utilizing and optimizing KE. Currently working also illustrates the principle of piezoelectric crystal and various sources of vibration.“The idea of energy source is applicable to sensors and transducers that are placed and operated for long time process to replace the sensor module batteries. Sensors are commonly called self sensors.”Piezoelectric transducer, which is an electromechanical, undergoes mechanical vibrations therefore it produces electricity. power source has many applications in agriculture, home application and street lighting and as energy source for sensors in remote locations.

3 illus, 10 ref

000989   BHOSALE S D, SHINDE U B (Electronics and Telecommunication Engineering Dep, CSMSS. Chh. Shahu Coll of Engineering, Aurangabad, Maharashtra, Email: drshindeulhas@gmail.com) : Feature extraction for Marathi compound character using KNN classifier. Int J Info Computing Sci 2019, 6(1), 99-104.

Compound character recognition of Handwritten Devanagari is one of the challenging tasks due to its complexity as compare to many other scripts as the language is challenging for recognition. Compound characters itself complex in structure in Marathi compared to other languages. It is written with combination of two or more characters in alphabets. The character may be formed with different sequence of combinations of basic characters, such as vowels and consonants for Marathi alphabets. The recognition of compound characters makes this task more challenging for recognition. The frequency of occurrence of compound characters in Marathi language is more as compared to other languages derived from devanagari script as more compound letters are included in Marathi. The various researchers used different classification techniques such as Neural Network, Soft Computing, Seventh Central Moment, SVM Classifier, wavelet transformation etc and derived various results. The paper presents a novel approach for recognition of unconstrained Marathi compound characters. The recognition is carried out using multistage feature extraction and classification scheme. This character tends to touch each other in different forms and so the segmentation of compound characters is difficult task because of high error rate and higher complexity. This paper, shows a similar investigation of Devanagari character recognition utilizing various feature techniques. In this paper we are using OCR method for recognition of compound text and then converting the recognized text.

6 illus, 22 ref

001010   GORANE P S (Mechanical Engineering Dep, G.S.Moze Coll of Engineering, Pune-411045, Maharashtra) : Design and fabrication of river cleaning machine. Int J Info Computing Sci 2019, 6(1), 30-46.

This project emphasis on design and fabrication of the river waste cleaning machine. The work has done looking at the current situation of our national rivers which are dump with crore liters of sewage and loaded with pollutants, toxic materials, debris etc. The government of India has taken charge to clean rivers and invest huge capital in many river cleaning projects like “Namami Gange”, „‟Narmada Bachao‟‟ and many major and medium projects in various cities like Ahmadabad, Varanasi etc. By taking this into consideration, this machine has designed to clean river water surface. Nowadays almost all the manufacturing process is being atomized in order to deliver the products at a faster rate. Automation plays an important role in mass production. In this project we have fabricated the remote operated river cleaning machine. The main aim of the project is to reduce the man power, time consumption for cleaning the river. In this project we have automated the operation of river cleaning with help of a motor and chain drive arrangement. Some needs of automation are described below. Here using RF transmitter and receiver are to control the cleaning machine. Automation can be achieved through computers, hydraulics, pneumatics, robotics, etc., of these sources, pneumatics form an attractive medium for low cost automation.

2 illus, 11 tables, 23 ref

001057   PAZHERI F R, OTHMAN M F, OTTUKULOTH S (Electrical Inspectorate Dep, Kozhikode, Kerala - 673 020, Email: fpazheri@hotmail.com) : Power station scheduling with energy storage. J Inst Eng India Ser B 2019, 100(1), 77–83.

Power utilities are encouraged to convert existing conventional power plant into hybrid power plant by installing available renewable power units and energy storage facilities in order to meet the rapid increase in power demand. Energy storage facilities (ESF) in such hybrid power plant ensure a consistent level of renewable penetration throughout the operation period. However, a proper scheduling model for such hybrid power plant is essential in order to achieve a significant savings in fuel cost. The unit commitment and economic dispatch scheduling for a hybrid system consisting of thermal, renewable energy source and ESF-based units are modeled and illustrated in this paper. The data of Neyveli Thermal Power Station II are considered here to demonstrate the importance and applicability of the proposed scheduling approaches. Dynamic programming method is used to find feasible states of the generation units, while sequential quadratic programming algorithm is used for economic dispatch of committed units. The proposed approach is novel, timely useful as reported by the analysis of results.

2 illus, 5 tables, 35 ref

001073   SAHOO P K, SATPATHY P K (Electrical Engineering Dep, Gandhi Institute for Education and Technology, Odisha - 752 060, Email: satpathy.pks@gmail.com) : Detection and classification of transmission line congestion by feed forward and radial basis function neural networks. J Inst Eng India Ser B 2019, 100(1), 69–75.

A novel scheme for detection and classification of transmission line congestion in power systems using feed forward and radial basis function neural networks is presented. In the detection stage, the neural network is trained to learn the complex mapping between various nonlinear multi-objective input functions and the specified target in order to arrive at the desired goal of identifying the lines being overloaded or congested. The cases indicating line congestion during the detection stage are presented to the radial basis function neural network for classification of the congested lines as per their degree of severity. The results obtained from MATLAB-based case study conducted on the IEEE 30-bus test system infer that the proposed feed forward neural network with Levenberg– Marquardt backpropagation scheme offers the fastest convergence as compared to other types of backpropagation schemes and the conventional approach as well. Further, the radial basis function neural network shows convincingly faster convergence during the severity classification stage.

5 illus, 4 tables, 21 ref

001027   KUMAR A W, VERMA H K, SINGH S (Electrical Engineering Dep, National Institute of Technology, Jammu & Kashmir - 190 006, Email: waheed.kumar83@gmail.com) : Incremental power improves relay selectivity to transmission line faults. J Inst Eng India Ser B 2019, 100(1), 61–8.

A research work published in 2014 reported a novel relaying principle for protection of transmission lines using signum function of instantaneous power flows at the two ends of the line. Subsequently, a detailed study of this relaying principle to evaluate its selectivity (sensitivity to detect all internal faults and stability on external faults and no-fault condition) was carried out and results were reported in another paper. The present paper reports a considerable improvement in the relay selectivity by using signum function of incremental powers at the two ends of the line. This principle of fault detection and classification has been tested by simulating a 230 kV, 50 Hz five-bus system in PSCAD/EMTDC. The various parameters of the study include dc offset, line load, location and type of fault and fault resistance. Various fault resistance values ranging from 0.01 ohm (solid fault) to 1000 ohms have been taken for simulation. The study has been carried out on two types of lines: a line between a source bus and a load bus, and a line connected between two source buses, and for two line lengths, namely 100 km and 200 km. Results of this detailed study are presented in the paper. The final outcome of the study is that the relay is able to detect all internal faults with all fault resistance values and all line loads. However, it operates on some external faults near the load bus, that is, has some transient overreach, for the first type of line. This tendency of operating on external faults is also lower than that with the instantaneous power-based relay.

4 illus, 2 tables, 8 ref

001054   PAI P, PRATYUSHA P L, NAIDU V P S (CSIR-National Aerospace Laboratories, Bangalore, Karnataka, Email: vpsnaidu@gmail.com) : Geo-localization of target in 3-dimensional coordinate using SRTM data. J Inst Eng India Ser B 2019, 100(1), 53–60.

This paper deals with Estimation of 3-Dimensional Geo-Location Coordinate (Latitude, Longitude and Elevation) of a given target location using the image of a Target captured from a Gimballed Camera mounted on an Unmanned Aerial Vehicle (UAV). The 2-Dimensional Geo-Location Coordinate (Latitude and Longitude) is estimated by the application of Geo-Location Algorithm based on the knowledge of target pixel location in the image. The Target Elevation is estimated by Elevation Estimation Algorithm using the 2-Dimensional Geo-Location Coordinate of target and Elevation Database such as NASA Shuttle Radar Topography Mission (SRTM) Database, National Geospatial-Intelligence Agency (NGA) SRTM Database and Advanced Space borne Thermal Emission and Reflection Radiometer Global Digital Elevation Model Version 2. This paper illustrates the Target Geo-Location Coordinate Estimation for two different experimental setup: UAV Simulation Setup and a Real Time Setup. The Geo-Location Estimation result obtained from the Simulation Setup is found to have localization error around 0.3 m, while the estimates from the Real Time Setup are found to have a higher localization error of around 2.3 m. The elevation result obtained using Elevation Estimation Algorithm for SRTM 1-Arc Second database is proved to be more accurate but this comes with a downside of having longer processing time when compared with other databases. NGA 3-Arc Second database provides the result with the shortest computation period.

11 illus, 7 tables, 10 ref

000984   ARTHUR B P B, BHASKARAN U (Electrical and Electronics Engineering Dep, Anna Univ, Chennai - 600 025, Email: blessing_arthur2007@yahoo.com) : Accurate determination of magnetic flux in axial flux induction machine using multi-slice approach and basic design equations. J Inst Eng India Ser B 2019, 100(1), 41–51.

The objective of this paper is to predetermine the magnetic circuit parameters of an Axial Flux Induction Machine (AFIM) viewed as a de-coiled version of radial flux induction machine. The geometry of AFIM leads to variation in basic design parameters like pole pitch etc. along the radius necessitating a compliant design equation which accommodates such variations. The magnetic circuit is seen as many parallel paths along each slide with varying geometry and the air gap flux is more accurately determined. Results are comparable with 3D-FEA simulation and match the experimental data obtained with a prototype 2.5 kW machine.

13 illus, 10 tables, 22 ref

001087   SMITHA M S G, SATYARAMESH P V, SUJATHA P (Electrical and Electronics Engineering Dep, Jawaharlal Nehru Technological Univ, Ananthapuramu - 515 002, Email: msgsmitha@gmail.com) : Usage based transmission cost allocation to wheeling transactions in bilateral markets. J Inst Eng India Ser B 2019, 100(1), 23–31.

Transmission cost allocation among market participants in restructuring of power industry has become an important task in view of bilateral transaction framework. This paper presents a usage based methodology of transmission cost allocation in deregulated power system under open access. A new methodology for allocating transmission cost to wheeling transactions considering Z_bus and contractual obligations made among suppliers and buyers is proposed in this paper. The usage coefficients are defined by taking the quantum of bilateral agreements made in the electricity markets so as to obtain fair utilization of transmission network. Accordingly this new approach calculates the utilization of each line by the generators and loads considering their contract obligations in the open access environment. The transmission costs are allocated among the transactions by using the converged load flow solution in this methodology. In this paper the allocation of the transmission costs mainly emphasize both technical and measure of ‘extent use’ of transmission resources. The proposed method has been illustrated with the help of a sample 6 bus (test) system, IEEE 118 bus system and comparison is done with analytical method for six bus system.

2 illus, 11 tables, 13 ref

001001   DHEEPANCHAKKRAVARTHY A, SELVAN M P, MOORTHI S (Electrical and Electronics Engineering Dep, National Institute of Technology, Tiruchirappalli - 620 015, Email: srimoorthi@nitt.edu) : Alleviation of power quality issues caused by electric arc furnace load in power distribution system using 3-phase four-leg DSTATCOM. J Inst Eng India Ser B 2019, 100(1), 9–22.

Electric Arc Furnaces (EAFs) play an essential role in the production of superior quality steel, using metal scrap as raw material. However due to its non-linear electrical characteristics, it creates lot of power quality problems in the 3-phase 4-wire power distribution system. In this paper, time domain based hyperbolic EAFs model is considered as an unbalanced, time-varying non-linear load and the power quality issues created by EAF are considered. A four-leg distribution static compensator (FL-DSTATCOM) is utilized for elimination of current harmonic and 3-phase current imbalance. Simultaneously, it nullifies the current flow in the neutral conductor, compensate the reactive power and rectify the poor PF which are caused by the EAFs in the power distribution system. The FL-DSTATCOM injects reactive and harmonics components of furnace current extracted using synchronous reference frame theory. In order to evaluate the compensation capability of FL-DSTATCOM under static and dynamic furnace loading conditions, the digital simulation is carried out using MATLAB/SIMULINK. The simulation results demonstrate that the FL-DSTATCOM is capable of making the supply current balanced and sinusoidal. It also helps in maintaining the power factor at point of common coupling near to unity and reduces the supply neutral current very close to zero.

9 illus, 2 tables, 27 ref

001062   PUSHPA Y G, NAGARAJU V, GOBINATH G (Central Power Research Institute, Bangalore - 560 080, Email: Pushpa063@gmail.com) : An improved pollution testing methodology for polymeric insulators: Analysis on surface coating and flashover voltage under solid layer test. J Inst Eng India Ser B 2019, 100(1), 1–8.

Polymeric insulators have found application worldwide in outdoor insulation system due to their better pollution performance. Since there are no standard laboratory test methods to analyse pollution performance of polymeric insulators, selection and dimensioning of proper insulator is still confusion for engineers and utilities. IEC and CIGRE working groups have recently suggested a test method for solid layer pollution testing of polymeric insulators. The uniformity of pollutant coating over hydrophobic insulator surface was not consistent with CIGRE Round Robin Test procedure. In this research work, a method of soaking the insulators in water as a part of preconditioning before actual pollutant spray was adopted and uniformity of coating was compared with CIGRE round robin test procedure. Critical analysis has been made on the loss and recovery of hydrophobicity characteristics on silicone insulators and its ability to transfer the hydrophobicity to pollution layer were observed and recorded over a period of 15 days with the proposed coating method. Solid layer pollution test was carried out on 66 kV long-rod insulators with the proposed test procedure and the results were compared with CIGRE procedure. 50 % Flashover Voltage (U_50%) of the insulator was determined before and after withstand test for both the test methods and standard deviation was calculated. The variation in the flashover voltage values has been calculated before and after withstand test. From the results, it’s been observed that, the hydrophobicity character was not influenced to the pollution layer in the given recovery period but the recovery time had an impact on flashover voltage. The deviations in flashover voltage value compared before and after withstand tests, found to be within 5 % for both CIGRE procedure and modified test procedure.

15 illus, 2 tables, 23 ref

001058   PAZHUHANFAR Y, EGHBALI B (Materials Science and Engineering Dep, Sahand Univ of Technology, Tabriz, Iran, Email: eghbali@sut.ac.ir) : Effect of processing parameters on microstructure and mechanical properties of AL6061/B₄C metal matrix composite fabricated by using stir casting, post-accumulative roll bonding and aging treatment. Trans Indian Inst Met 2019, 72(2), 545–58.

In the present research, Al6061-based composites reinforced with micron-sized B₄C particles were fabricated by the combination of stir casting and postprocessing via accumulative roll bonding (ARB) and aging treatment. Microstructural evolutions of processed samples were investigated using optical and scanning electron microscopy. Also, mechanical properties were studied by micro-hardness measurements and room temperature tensile testing. From obtained results, it was concluded that the as-cast composites had a lower tensile strength and elongation compared with accumulative roll-bonded counterparts. Post-processing by accumulated roll bonding decreased the deficiencies aroused during stir casting and improved particle distribution. It was observed that increasing ARB cycles decreased the particle-free zones and particle clusters.

13 illus, 1 table, 33 ref

000994   CHEN Y, FENG Y, WANG L, GUO E, WANG L, JIA G (Harbin Univ of Science and Technology, Harbin- 150 040, People’s Republic of China, Email: fyc7806067@163.com) : Effect of cooling rate on solidification behavior and microstructure evolution of As-Cast Mg–5Al–2Ca–2Sm alloy. Trans Indian Inst Met 2019, 72(2), 533–43.

In the present work, the Mg–5Al–2Ca–2Sm alloy was fabricated in stepped type sand mold, the cooling rate varied from 0.3 to 3.5 °C/s. The solidification behavior and microstructure evolution of Mg–5Al–2Ca–2Sm alloy were carried out by computer-aided cooling curve thermal analysis method, optical microscope (OM), X-ray diffraction analysis, scanning electric microscope and transmission electron microscope. The experimental results showed that the nucleation temperature of α-Mg phase decreased with increasing cooling rate. In addition, the grain size of α-Mg phase in Mg–5Al–2Ca–2Sm alloy were 95.47 ± 1.2 μm, 88.65 ± 1.5 μm, 71.24 ± 1.7 μm and 42.35 ± 1.3 μm, which were responds to the cooling rates of 0.3 °C/s, 0.5 °C/s, 1.2 °C/s and 3.5 °C/s, respectively. There were both Al₂Sm (particle structures) and (Mg, Al)₂Ca (lamella structure) phases in the Mg–5Al–2Ca– 2Sm alloy under different cooling rates. However, there were Mg₂Ca (blocky structure) in the samples cooled in 0.5 °C/s and 0.3 °C/s. The solidification sequence of precipitated phase in Mg–5Al–2Ca–2Sm alloy could be obtained as: Al2Sm → a-Mg → (Mg, Al)2Ca → Mg2Ca. Furthermore, the volume fraction of precipitated phase increased with the cooling rate. The volume fraction of precipitated phase in Mg–5Al–2Ca–2Sm alloy were 11.86 ± 0.7 %, 13.05 ± 1.2 %, 16.19 ± 0.8 % and 20.77 ± 0.9 %, which were responds to the cooling rates of 0.3 °C/s, 0.5 °C/s, 1.2 °C/s and 3.5 °C/s, respectively.

16 illus, 24 ref

001041   MISHRA A, GAUTAM S, SHARMA T (Mechanical Engineering Dep, Sharda Univ, Greater Noida, Uttar Pradesh, Email: 6akanksha2@gmail.com) : Gasification of Jhama Coal using statistical design of experiment. Trans Indian Inst Met 2019, 72(2), 523–31.

In the present investigation, an attempt has been made to explore the effect of ash content on the gasification characteristics of Jhama coal. The two levels of ash content were selected for this study. The samples were obtained by gravity separation of Jhama coal. These two samples (clean Jhama coal: low ash and reject Jhama coal: high ash) were subjected to gasification at different temperatures for different time intervals, and carbon dioxide gas was used as a gasifying agent. The effect of temperature and residence time on gasification of two samples with different ash contents has been investigated. The values of activation energy of low-ash and high-ash Jhama coal samples have been obtained in the range of 51–66 kJ/mol and 37–43 kJ/mol, respectively. In addition, design of experiments was performed using response surface methodology (RSM) under 2³ full factorial designs. RSM-based empirical models were developed for low-ash and high-ash Jhama coal samples to correlate process variables to the response of interest.

11 illus, 5 tables, 42 ref

001053   OZTOPRAK N , YENI C E, KIRAL B G (Mechanical Engineering Dep, Dokuz Eylul Univ, Izmir-35390, Turkey, Email: nahit.oztoprak@deu.edu.tr) : Dissimilar friction stir butt welding of AA6061-T6 and AA6061/ SiCp composite: Microstructural characteristics, impact toughness, hardness, strength under transverse impact. Trans Indian Inst Met 2019, 72(2), 511–21.

Impact response of dissimilar friction stir welded (FSWed) joints between a monolithic alloy and metal matrix composite has not been yet reported and thus requires a detailed investigation. Therefore, an exhaustive research on the microstructure, microhardness, tensile properties, fracture toughness and failure response under transverse impact of the FSWed AA6061-T6/AA6061 + SiCp joint was conducted within the study. The plates of size 300 × 120 × 3.2 mm³ were friction stir butt welded using a tool rotational speed of 1000 rpm, welding speed of 80 mm/min, tilt angle of 1^o and a penetration depth of 0.2 mm into the upper surface of the workpieces. The obtained results indicated that there is no defect in the weld zone of the FSWed dissimilar joint. Microhardness distribution across the mid-thickness of the joint demonstrated superior Vickers hardness within the nugget zone compared to that of AA6061-T6. In addition, tensile rupture took place away from the weld region on the advancing side in the joint for all transverse tensile test specimens. It was also demonstrated that the FSW process resulted in a significant enhancement in fracture toughness compared to those of the base materials. Furthermore, weld nugget of the joint withstood the applied transverse impact energies ranging between 2.5 and 7.5 J.

17 illus, 3 tables, 45 ref

001031   LV Y, CHEN D, TANG J, LI J, YANG D, CHEN B (Soochow Univ, Suzhou- 215 021, China, Email: chend@suda.edu.cn) : Recovery of iron from pyrite cinder with reduction–magnetic separation process in presence of sodium salt. Trans Indian Inst Met 2019, 72(2), 501–10.

This paper investigated the iron recovery form pyrite cinder with the coal-based reduction–magnetic separation process in the presence of sodium sulfate additive. The functional mechanism of sodium sulfate, reduction behavior of pyrite cinder, and separation mechanism of iron mineral and gangue were investigated through discussing the influences of sodium sulfate dosage, reduction temperature, reduction time, and grinding fineness and analyzing the reduced briquette and magnetic concentrate by using X-ray diffraction, optical microscope and scanning electron microscope and energy-dispersive spectrometer (SEM–EDS). The results show that sodium sulfate can improve the occurrence state and embedded relationship of gangue. Furthermore, the sodium sulfate can promote the interconnection of metallic iron grains, which intensifies the separation of iron mineral and gangue. Under the conditions of pyrite cinder briquette containing 3% Na₂SO₄, reducing at 1050 ^oC for 80 min, the grinding fineness of 76.8 % less than 45 lm, and magnetic field intensity of 73 mT, the iron grade of magnetic concentrate and iron recovery rate were 92.02 % and 98.63 %, respectively.

15 illus, 4 tables, 23 ref

000988   BASKORO A S, MUZAKKI H, KISWANTO G, WINARTO W (Mechanical Engineering Dep, Indonesia Univ, Depok- 16424, Indonesia, Email: ario@eng.ui.ac.id) : Mechanical properties and microstructures on dissimilar metal joints of stainless steel 301 and aluminum alloy 1100 by microresistance spot welding. Trans Indian Inst Met 2019, 72(2), 487–500.

Aluminum and stainless steel are metals that have some mechanical property advantages. Welding technology has been developed to join both different and dissimilar metals applied in a construction. The property advantages have been used to improve the performance of a construction. However, welding performance still creates a problem as a result of properties’ differences in metals. This study investigated the mechanical properties of a steel-aluminum joint with the thickness of less than 1 mm, welded by resistance spot welding (RSW); it is called a micro-RSW. Mechanical properties of the joint were analyzed by tensile test and were measured at the fracture area on the tensile test specimen. Moreover, it also analyzed intermetallic microstructure in the nugget or welding joint. Welding time of 8 CT was an optimum parameter on a welding process to get the maximum load. The fractographic structure of a stainless steel-aluminum joint showed a brittle nugget. Moreover, the fracture area on the aluminum side was larger than that of the stainless steel. Intermetallic compound (IMC) was created by melting and joining it through the heat input in the welding process. IMC in SS301-AA1100 nugget affected a brittle joint.

16 illus, 4 tables, 33 ref

001072   SAFDARIAN R (Mechanical Engineering Dep, Behbahan Khatam Alanbia Univ of Technology, Khoozestan, Iran, Email: safdarian@bkatu.ac.ir) : Failure prediction of superheater tubes in rotary tube bending process using GTN damage model. Trans Indian Inst Met 2019, 72(2), 475–86.

Superheater tubes are one of the main parts of boilers which are subjected to high temperature and stress. Fracture is one of the main defects which happen during the forming process of these tubes. In the present study, tube rotary draw bending (RDB) process is used for forming of superheater tube. Gurson–Tvergaard–Needleman (GTN) damage model is used for fracture prediction in the numerical simulation of tube RDB. Response surface methodology is coupled with the finite element to identify the GTN parameters. For this purpose, different sets of GTN parameters are used to simulate the uniaxial tensile test in the Abaqus software. Effect of GTN parameters is investigated on the predicted stress–strain curve of the uniaxial tensile test in the numerical simulation. The bestidentified GTN parameters are used in the finite element simulation of tube RDB of superheater tube. Results indicate that there is an appropriate agreement between the predicted fracture location of the numerical and experimental sample after RDB.

11 illus, 6 tables, 29 ref

000981   AGNIHOTRI A, SINGH P K, MISHRA R, MAZUMDAR D (Materials Science and Engineering Dep, Indian Institute of Technology, Kanpur, Uttar Pradesh, Email: dipak@iitk.ac.in) : Steady-state materials and enthalpy balance: Applications to ferroalloy production and industrial-scale validation. Trans Indian Inst Met 2019, 72(2), 455–73.

Steady-state material and enthalpy balance models for ferroalloy production in submerged arc furnace (SAF) have been developed. Two different types of ferroalloys, used commonly in the steel industry, namely high-carbon ferromanganese and high-carbon silicomanganese, were considered, and appropriate mass and energy conservation expressions were developed considering input, output and losses of various entities to/from two different 33 MVA SAFs. Several plant-specific parameters, such as material loss due to handling, off-gases, hot metal, slag and off-gas temperatures as well as heat losses from the SAFs, were incorporated in order to develop a predictive material and energy balance framework. Embodying types of feed materials, their composition and amount together with product composition along with relevant thermodynamic data, and amount of metal and slag produced in the two processes were estimated. Similarly, external power required to produce a given amount of ferroalloy was calculated by coupling material balance with an appropriate energy balance calculation scheme. It was demonstrated that estimates of hot metal production, slag generation and external electrical energy requirement were in reasonable agreement with industrial operating data. A graphical user interface was also developed to carry out material and energy balance calculations efficiently.

8 illus, 7 tables, 11 ref

001079   SHARMA S K, MAHESHWARI S, SINGH R K R (Mechanical Engineering Dep, Thapar Institute of Engineering and Technology, Punjab - 147 004, Email: satishsharma847@gmail.com) : Modeling and optimization of HAZ characteristics for submerged arc welded high strength pipeline steel. Trans Indian Inst Met 2019, 72(2), 439–54.

Heat affected zone (HAZ) is the most critical part of welded pipe in oil and gas pipelines as HAZ shows more susceptibility toward embrittlement and weld cracking. It happens because microstructural changes occur due to high heat of welding. Heat input and preheating temperature together control the cooling time of weld which in turn determines the weld microstructure and its mechanical properties. Therefore, in the present study, effect of heat input as well as preheating temperature on the characteristics of the HAZ in submerged arc-welded high-strength low alloy (HSLA) pipeline steel was studied. Hardness and area of HAZ were observed and analyzed as HAZ characteristics. Heat input of the process was varied by changing the voltage, welding speed, wire feed rate and contact tube to work distance. Experiments were designed using central composite rotatable design (CCRD) approach, and using response surface methodology (RSM), process modeling was done. For the purpose of single- as well as multi-characteristic optimization, desirability approach was used. Relationship of heat input and critical cooling rate with HAZ characteristics and its microstructure was also revealed. Inclusion of preheating temperature led to significant improvement in the HAZ characteristics of the weld.

11 illus, 8 tables, 31 ref

001095   VIGNESHKUMAR M, VARTHANAN P A, RAJ Y M A (Mechanical Engineering Dep, Sri Krishna Coll of Engineering and Technology, Coimbatore, Tamil Nadu, Email: vigneshkumarmech@gmail.com) : Finite element-based parametric studies of nugget diameter and temperature distribution in the resistance spot welding of AISI 304 and AISI 316L sheets. Trans Indian Inst Met 2019, 72(2), 429–38.

Resistance spot welding (RSW) of dissimilar metals is prominent in automobile industries to utilize the material properties of both the metals. RSW of dissimilar austenitic stainless steel sheets (AISI 304/316L) is investigated in this paper by varying the process parameters such as welding current and weld time at three different levels. Tensile shear test and macrostructural examinations are carried out to analyze the performance of spot welds. A three-dimensional model is also developed using commercial finite element analysis software ABAQUS FEA to predict the nugget diameter and thermal distribution profile through simultaneous structural electrothermal analysis with temperature-dependent material properties. The generated model is validated by comparing the predicted nugget diameter with experimental nugget diameter. Experimental results show good coherence with the simulation results, and the macrostructure of the spot-welded joints indicates successful welding of dissimilar sheets with defect-free fusion zone.

14 illus, 2 tables, 20 ref

001004   EL-SADEK M H, FOUAD O A, MORSI M B, EL-BARAWY K (Pyrometallurgy Dep, Central Metallurgical R&D Institute (CMRDI), Cairo, Egypt, Email: mohamedhussien2002@hotmail.com) : Controlling conditions of fluidized bed chlorination of upgraded titania slag. Trans Indian Inst Met 2019, 72(2), 423–7.

Titanium tetrachloride with 98 % purity was successively synthesized by chlorination of upgraded titania slag (88 % TiO₂, 2.9 % Fe₂O₃) using chlorine gas in the presence of activated charcoal at 1173–1373 K in a fluidized bed chlorinator. The different parameters affecting the chlorination processes such as carbon source, carbon amount, temperature and time of chlorination were studied. Moreover, kinetics of chlorination of upgraded titania slag was studied. The results showed that the chlorination of upgraded titania slag was mainly controlled by diffusion of chlorine gas with calculated apparent activation energy of 11.9 kJ/mole.

7 illus, 4 tables, 12 ref

001063   RAGHU K, BALACHANDRAN G, RAVICHANDAR D (JSW Steel Limited, Salem, Tamil Nadu, Email: karthick.ragu@jsw.in) : Microstructure and mechanical properties in warm forged 27MnSiVS6 microalloyed steel. Trans Indian Inst Met 2019, 72(2), 411–21.

The mechanical properties and microstructure of warm forged 27 MnSiVS6 steel was evaluated at temperatures between 850 and 760 ºC. The strength values showed enhancement by about 50 MPa, while the impact toughness was almost doubled. The microstructure showed increase in ferrite content with decreasing warm forging temperature, and the ferritic grains showed finer grain structure. While the increased ferrite content resulted in limiting the strength enhancement, the fineness of the grain structure led to a significant enhancement in impact toughness. The ductile-to-brittle transition temperature was pushed to a significantly low temperature in the warm forged steel compared to the hot-rolled steel. The microstructure evolution at various stages of processing was brought out.

9 illus, 5 tables, 12 ref

000986   BALACHANDRAN G, MENAKA K, RAVICHANDAR D (JSW Steel Limited, Salem - 636 453, Email: g.balachandran@jsw.in) : Influence of manganese and boron alloying and processing conditions on the microstructure and the mechanical properties of 0.4 % carbon steels. Trans Indian Inst Met 2019, 72(2), 401–9.

The performance of three steels with 0.4 % carbon content was evaluated in the warm forging condition and benchmarked against the as-hot-deformed and hardening and tempering condition. The steels include a plain carbon steel S45C, a carbon-manganese steel 40Mn5 and a carbon-manganese-boron-alloyed steel 15B41. Such lean alloyed steels are preferred by automotive companies for component manufacture. In the as-hot-rolled condition, the steel with a ferrite pearlite microstructure shows, a good strength and lowest impact toughness. In the hardened and tempered condition at 650 ºC, a tempered mawrtensite microstructure with a moderate improvement in strength and significant enhancement in impact toughness, than the hot-rolled steel, is obtained. The steel subjected to warm forging at 760 ºC, shows a ferrite pearlitic microstructure with a moderate improvement in strength but with the highest impact toughness level. The microstructure evolution at the various processing conditions has been brought out and correlated with the mechanical properties. The relative merits in processing the steels at the different processing conditions show that warm forging is an effective means to achieve the highest strength toughness combination in a ferrite pearlitic matrix.

2 illus, 5 table, 16 ref

001102   YOUSEFI M, MOFRAD N S B, KERAHROODI M S A, BARIKBIN H S, MOUDI M (Energy and Mechanical Engineering Dep, Shahid Beheshti Univ, Tehran, Iran, Email: masoud_yousefi@hotmail.com) : Effect of the supplementary aging process on the microstructure and mechanical properties of Mg–5Sn and Mg–5Sn–0.5Zn alloys. Trans Indian Inst Met 2019, 72(2), 383–99.

This paper presents a novel aging process consisting of two stages: an aging at 250 ºC for 12 h and a supplementary aging at 70 ºC for 18 h. The ingots of Mg– 5Sn and Mg–5Sn–0.5Zn alloys were solution heat-treated for 24 h at 480 C and then quenched in water. Afterward, aging treatments were performed. To compare the effects of this process on age hardening response of both alloys, other aging treatments were performed at 200 ºC for 60 h and at 280 ºC for 12 h. The age hardening responses were measured by the Vickers hardness test. The structure of specimens was investigated by XRF, DSC, XRD, and FESEM. Also, mechanical properties were determined by tensile test and Charpy impact test. Although by using supplementary aging process, maximum hardness of these alloys is not very different in comparison with single- as well as double-aging processes, the necessary times of aging processes are significantly lower than those at around 90 %, 85 %, and 50 %. After the aging process, the microstructure of Mg–5Sn and Mg–5Sn–0.5Zn alloys consists of α-Mg, nano-metric particles of Mg₂Sn, and GPzones. In Mg–5Sn alloy, after supplementary aging process, the yield strength, ultimate tensile strength, and elongation increase to 151.2 MPa, 221.2 MPa, and 8 % sequentially. In Mg–5Sn–0.5Zn alloy, the YS, UTS, and elongation increase to 154 MPa, 224 MPa, and 7 %, respectively. The impact energy in both alloys is 6.63 J and 7.05 J, respectively.

18 illus, 4 tables, 47 ref

001037   MANDAL G K, KAMARAJ A, HUMANE M M, MINJ R K, DAS S K, RAMANA R B V, VENUGOPALAN T (CSIR-National Metallurgical Laboratory (NML), Jamshedpur, Jharkhand, Email: srhsbioboy@yahoo.co.in) : Development of speciality grade wire by controlling the inclusions in high-carbon steel using synthetic slag treatment. Trans Indian Inst Met 2019, 72(2), 369–81.

The high-carbon wire rods essentially permit controlled traces of the aluminium and calcium dissolved in the molten steel bath due to the generation of un-deformable complex oxide inclusions. These inclusions can be controlled by treating the liquid steel with suitable synthetic slag. In the present investigation, slag with suitable composition was synthetically prepared based on the thermodynamic study. After melting the plant wire rods, synthetic slag was added in the bath and slag–metal reactions were carried out at around 1600 ºC for a pre-specified period. Experimental results showed significant improvement in inclusion rating of hot-rolled specimens prepared by induction melting for the residence time of about 30 min across the slag–metal reaction. It thus depicts that slag–metal reaction residence time of 15 min is rather less than the residence time of 30 min for any significant improvement in inclusion rating under identical reactions across the slag–metal interface.

13 illus, 5 tables, 23 ref

001076   SAMEER M D, BIRRU A K (Mechanical Engineering Dep, National Institute of Technology, Manipur, Imphal, Email: anilbirru@gmail.com) : Investigations on microstructural evolutions and mechanical properties of dual-phase 600 steel and AA6082-T6 aluminum alloy dissimilar joints fabricated by friction stir welding. Trans Indian Inst Met 2019, 72(2), 353–67.

In this research work, dual-phase 600 steel grade and AA6082-T6 aluminum alloy dissimilar flat plates of thickness 2 mm were fabricated by using friction stir welding. Three tool rotational speeds of 560, 710 and 900 rpm, three tool traverse speeds of 24, 32 and 40 mm/ min, three tool offsets of 0.8, 1.3 and 1.8 mm and constant tool tilt angle of 0.5 were used to obtain the defect-free welds. Macrostructure, microstructure evolutions, tensile strength, microhardness tests were carried out to assess the welding properties of dissimilar steel and aluminum welded joints. The highest tensile strength of 240 MPa with the joint efficiency of 85% of the base metal was obtained when the parameters were set to tool rotational speed of 710 rpm, traverse speed of 40 mm/min, tool tilt angle of 0.5 and tool pin offset of 1.3 mm using a tungsten carbide tool. The highest microhardness of 246 HV was obtained in the stir zone. Scanning electron microscopy was used to study the joint interface structure. The presence of Fe₅Al₈ and FeAl intermetallic compounds was confirmed by energy-dispersive X-ray and X-ray diffraction analysis.

19 illus, 4 tables, 50 ref

001029   KUNSHAN X, FENG M, QIU X (Yantai Univ, Yantai, China, Email: 17911162@qq.com) : Distinguishing welding defects from the stress concentration zone using metal magnetic memory field parameters. Trans Indian Inst Met 2019, 72(2), 343–51.

In this study, we propose a technique for differentiating MMMT signals from the welding defects and stress concentration zones by evaluating changes in the intensity of the magnetic memory signal and gradient of its change. The results demonstrate that the average and maximum values of the magnetic field intensity gradient vary relative to the presence of a welding defect zone; this gradient can be seen as the area under the magnetic field intensity curves. These parameters can be considered as a basis for distinguishing welding defects from the stress concentration zone. Finally, we present diagnosis and damage determinations of various welding defects and stress concentrations and propose a connection to magnetic and non-magnetic defects. The technique presented here can be potentially used to enhance the MMMT application for better diagnosis and understanding of welded joints and failure mechanisms.

8 illus, 3 tables, 36 ref

001014   HONG L-K, CHENG R, AI L-Q, SUN C-J (North China Univ of Science and Technology, Tangshan- 063 210, China, Email: 176535527@qq.com) : Mechanism of carbon diffusion in the iron sheet during gas– solid decarburization. Trans Indian Inst Met 2019, 72(2), 335–42.

To investigate the diffusion of carbon in the iron sheet during gas–solid decarburization in a weak oxidative atmosphere (Ar + H2 + H2O), the microstructures of iron sheets following decarburization were observed through SEM. The carbon gradient following decarburization in the iron sheet along the thickness direction was detected in this study. The results showed that the iron sheet along the thickness direction following decarburization consisted of three layers: the L1 layer (ferrite phase) that was near the surface, the L2 layer (cementite phase) that was between the L1 + L3 layers, and the L3 layer (cementite + ferrite + graphite phase) that was in the center of the sample. The depth of the decarburization layer (L1 + L2) showed a good linear relation with the square root of the decarburization time. The carbon gradient in iron sheet along the thickness direction was of ladder type during decarburization. The carbon content in the center of iron sheet was influenced by the decarburization time or the temperature. The carbon migration in iron sheet consisted of stable carbon decomposition and free carbon diffusion. The carbon migration in the S2 stage of iron sheet was the controlling step of the entire decarburization process.

8 illus, 1 table, 18 ref

001052   OZCAN A, YILMAZ D, KOC N, GASAN H (Eskisehir Osmangazi Univ, Eskisehir-26480, Turkey, Email: d.yilmaz@ogu.edu.tr) : Effect of calcium hexaborate pentahydrate as a lubricant additive in commercial engine oil. Trans Indian Inst Met 2019, 72(2), 327–33.

Boron-based compounds can be widely used in tribological applications such as lubricants, anti-wear additives and in addition to this, these compounds, especially borates, are environment friendly, easily available and cheap materials. In particular, nanoparticles are used as additives or lubricants to prevent friction and wear on steels. Nano-sized lubricants with novel unique properties such as wear resistance, low friction coefficient and high load capacity can be used as tribological materials. In this study, different amounts of platelet ladder-like calcium hexaborate pentahydrate (CaB₆O₁₀5H₂O) nanoparticles were used as a lubricant additive to characterize the effect of CaB₆O₁₀5H₂O on tribological properties of AISI 52100 steel. Synthesized calcium hexaborate pentahydrate nanoparticles were dispersed with different concentrations (0.1 %, 0.5 % and 1.0 % wt.) in commercial engine oil, and tribological tests were conducted using ball-on-disk geometry. The morphology of surface was studied using scanning electron microscopy (SEM). Coefficient of friction was decreased by about 26.6 % with the contribution of 1.0 % wt. of CaB₆O₁₀5H₂O into the commercial engine oil (SAE10W40).

11 illus, 3 tables, 28 ref

001081   SINGH A, PARAMESWARAN P, THIRUMURUGESAN R, PANDA A K, MURUGESAN S, CHANDRAMOULI S (Physical Metallurgy Div, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102, Email: akash@igcar.gov.in) : Development and characterization of MgO coatings on 316L stainless steel. Trans Indian Inst Met 2019, 72(2), 319–25.

The present work deals with the development of MgO coatings on ASTM 316L stainless steel using pulsed laser deposition technique employing KrF excimer laser (λ = 248 nm). Two important process variables, namely oxygen partial pressure and substrate temperature, were varied to get uniform coatings. The process parameters were optimized based on the microstructure and uniformity of the coatings, which had the direct bearing on the performance of the coating. Structural, morphological and microstructural characterizations of the coatings were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy. While XRD studies confirmed the phase purity and the strain associated with the coating and the substrate, SEM studies revealed the microstructural integrity and morphology of the coatings in addition to establishing the chemistry of coatings. Field testing of the coatings for their sodium compatibility, particularly in aggressive conditions of incineration, confirmed the successful performance of the coatings.

11 illus, 2 tables, 17 ref

001013   HAJISAFARI M, CHAKERIZADE A, FALLAH M, DARBAND G B (Metallurgical and Materials Engineering Dep, Islamic Azad Univ, Yazd, Iran, Email: hajisafari1001@iauyazd.ac.ir) : Characterization of Zn–Mn phosphate coating deposited by cathodic electrochemical method. Trans Indian Inst Met 2019, 72(2), 307–17.

Electrophosphating is a novel method that is used for accelerating the low-temperature phosphating bath. In this study, Zn–Mn phosphate coating was fabricated on mild steel substrate using the cathodic electrochemical method. Afterward, the effect of electrolyte pH and applied current density was investigated on coating properties. Microstructure, phase analysis and corrosion resistance of coating were evaluated using SEM, X-ray diffraction, potentiodynamic, immersion test and electrochemical impedance spectroscopy tests, respectively. Results indicated that the metallic and nonmetallic phases are present in the coating fabricated by the cathodic electrochemical method. The results of the corrosion evaluation tests indicated that the best coating resistance is obtained at pH = 2.5 and 20 mA/cm² applied current density, due to compact phosphate layer of the coating. By further increase in pH and applied current density, the coating with poor corrosion resistance is formed due to high porosity of coating obtained at these conditions.

12 illus, 2 tables, 28 ref

000992   CARTIGUEYEN S, MAHADEVAN K (Mechanical Engineering Dep, Karaikal Polytechnic Coll, Puducherry - 609 609, Email: scartigueyen@rediffmail.com) : Effects of thermal conditions on microstructure and mechanical properties of Cu–SiCp Surface nanocomposites by friction stir processing route. Trans Indian Inst Met 2019, 72(2), 289–305.

In the present investigation, surface-level nanocomposites were prepared by friction stir processing (FSP) using 50 nm-sized SiC particles with a cluster of blind holes as particulate deposition technique on a 6-mmthick pure Cu plate. Effects of thermal conditions during FSP by three process parameters in three levels using response surface methodology on microstructure and mechanical properties were studied. Regression models were developed for various responses, and ANOVA tool was used to check the adequacy of the developed models. The results showed that the peak temperature achieved during FSP played a vital role in deciding the microstructure of Cu–SiC nanocomposites and the corresponding mechanical properties. FESEM-based microstructural characterizations revealed a uniform dispersion of SiC and its well bonding with the copper matrix. Nanocomposite layers exhibited superior microhardness and dry sliding wear characteristics than the matrix metal. FSP was identified as a low energy consumption route for the successful fabrication of surface-level Cu/SiCp nanocomposites.

16 illus, 9 tables, 35 ref

001038   MANDATI S, MISRA P, SARADA B V, RAO T N (International Advanced Research Center for Powder Metallurgy and New M, Telangana - 500 005, Email: sarada@arci.res.in) : Copper chalcopyrites for solar energy applications. Trans Indian Inst Met 2019, 72(2), 271–88.

Solar photovoltaic (PV) technology is a reliable and environmental friendly alternative for electricity generation. There are a number of solar PV technologies at different maturity levels, ranging from well-established and commercialized silicon PV to still in conceptual and R&D phase quantum dot and organic/polymer solar cells. Chalcopyrite solar cells, named so because of the thin absorber layer of Cu-based chalcopyrite materials used in these cells, are one of the frontrunners in thin-film PV technology owing to their tunable direct bandgap, large absorption coefficient and long-term stability. Among all Cu-chalcopyrite materials, copper indium selenide (CISe) and copper indium gallium selenide (CIGSe) are most suitable for use as light-absorbing layer. Although CISe and CIGSe absorber-based PV modules are being produced commercially for several years now, the technology is yet to mature fully as there is still scope for improvement in efficiency, manufacturability and cost reduction. The present article discusses the status of CISe-/CIGSe-based thinfilm PV technology while primarily focusing on the absorber material. Different vacuum and non-vacuum methods for fabricating these materials are reviewed along with their merits/demerits and suitability to large-scale production. Current status of commercial maturity for CIGSe PV is discussed while providing general process details of selected industrial manufacturers. Existing bottlenecks for this technology are deliberated, and future directions for improvement in laboratory-scale efficiency and manufacturability are outlined.

10 illus, 1 table, 157 ref

001007   GAO C, SHEN M, LIU X, WANG L, CHEN M (Science and Technology Liaoning Univ, Anshan, Liaoning, People’s Republic of China, Email: lnassmg@163.com) : End-point prediction of BOF steelmaking based on KNNWTSVR and LWOA. Trans Indian Inst Met 2019, 72(1), 257–70.

Basic oxygen furnace (BOF) steelmaking plays an important role in steelmaking process. Therefore, research on BOF steelmaking modeling is very necessary. In this paper, a novel combination prediction model has been proposed, which consists of a time series prediction model and a compensation prediction model. Both models are established by k-nearest neighbor-based weighted twin support vector regression (KNNWTSVR) algorithm. By introducing Le´vy flight algorithm and inertia weight, an improved algorithm of whale optimization algorithm (WOA) called Le´vy flight WOA has been initially proposed to solve the optimization problem in the objective function of KNNWTSVR. The simulation results show that the proposed models are effective and feasible. Within different error bounds (0.005 % for carbon content model and 10 ºC for temperature model), the strike rates of carbon content and temperature both achieve 93 %, and a double strike rate of 86 % is obtained, which can provide a significant reference for real BOF applications, and the proposed method is also appropriate for the prediction models of other metallurgical applications.

7 illus, 6 tables, 33 ref

001026   KESHTIBAN P M, BASHIRZADEH F (Urmia Univ of Technology, Urmia, Iran, Email: pmkmech@gmail.com) : Experimental investigation of multi-pass ECMAP process. Trans Indian Inst Met 2019, 72(1), 239–44.

Discontinuous part production as one of the main defects of single-pass equal channel angular pressing process was almost solved by studies suggesting equal channel multi-angular pressing (ECMAP) process. In the suggested method, multiple pressing operations are performed continuously without bringing the sample out of the mold. Thus, more uniform pieces are produced with less time consumption. In the present study, ECMAP process on strip-type products was done frequently up to three passes. The microstructurally transformed samples after each pass were extracted and compared. Also, to assess possible improvements in mechanical properties, tensile tests were done on all samples. Furthermore, the microstructural evolutions for each pass were investigated by X-ray diffraction analysis. According to the obtained results, the strength of samples was increased up to 49 % in the first pass while it was raised by 45 % and 13 % for second and third passes, respectively. Moreover, 49, 33 and 34 % reduction in the grain size were revealed by metallographic outcomes after the first, second and third ECMAP passes, respectively.

5 illus, 1 tables, 13 ref

001035   MALLIPUDI S R, NALLU R (Mechanical Engineering Dep, Andhra Univ, Visakhapatnam - 530 003, Email: s2srinu@gmail.com) : Effect of scandium and zirconium additions on mechanical properties of Al–Mg–Mn alloy. Trans Indian Inst Met 2019, 72(1), 227–38.

The present study was carried out to investigate the effect of adding Sc–Zr to Al–Mg–Mn alloys on microstructure characteristics and mechanical properties. The investigated alloys, namely Al–4.2Mg–0.6Mn alloy, Al–4.2Mg–0.6Mn–0.2Sc–0.1Zr alloy, Al–4.2Mg–0.6Mn– 0.4Sc–0.1Zr alloy, and Al–4.2Mg–0.6Mn–0.6Sc–0.1Zr alloy, were produced by stir casting to form plates and treated with cold rolling. The results showed that the alloying with Sc in combination with Zr had a strong influence on the microstructural characteristics and mechanical properties with significant strengthening of the Al–Mg–Mn alloys.

17 illus, 4 tables, 38 ref

000996   DADRASI A, BEYNAGHI M, FOOLADPANJEH S (Mechanical Engineering Dep, Islamic Azad Univ, Shahrood, Iran, Email: ali.dadrasi@gmail.com) : Crashworthiness of thin-walled square steel columns reinforced based on fractal geometries. Trans Indian Inst Met 2019, 72(1), 215–25.

In this paper, the crashworthiness of steel thinwalled square columns was investigated. These structures were reinforced with three types of reinforcers. The first type was aluminum shells which were placed inside the steel columns based on a specific fractal geometry, and two other types were aluminum and polyurethane foams. All samples were placed under axial loading, and fractals were thinned out up to three stages. At each stage, the effectiveness of aluminum shells alone and also in the presence of polyurethane and aluminum foams has been investigated. Also, the effect of foams’ location and in or out of fractal geometry, was studied. The results showed that the presence of reinforcers with different geometries and materials improved the energy absorption. As the fractal geometry of the reinforcers becomes smaller, the energy absorption capacity increases. The presence of the foams well compensated the load–displacement diagram drop after the initial peak and made the energy absorption behavior more ideal. On the other hand, polyurethane foam showed a significant effect on buckling control so that in one of the samples it prevented buckling. Comparison of the studied samples showed that the energy absorption was better when polyurethane foam prevailed. The effect of the second-stage fractal geometry was almost twice the fractal geometry of the first stage. The best choice among the discussed examples was an absorbent in the second stage with foam, in which the polyurethane foam predominated. Finally, some results were validated.

31 illus, 1 table, 23 ref

001066   RAJU R, SIVALINGAM V, SUN J, NATARAJAN M, ZHAO Y (Research Centre for Aeronautical Component Manufacturing Technology, Jinan, China, Email: svkceg@gmail.com) : Experimental and Taguchi-based grey approach of laser metal deposition technique on nickel-based superalloy. Trans Indian Inst Met 2019, 72(1), 205–14.

Thin sections of Inconel 718 sample was treated with laser-based metal deposition using a CW CO₂ laser. The Taguchi-based grey relational approach was incorporated for determining the optimized process characteristics of the laser treatment. Laser scan speed was varied at a constant laser power in order to analyze the effect of cooling rate and the subsequent thermal gradient on the microstructure and other properties of the base alloy. The presence of γ' -(Ni₃Al, Ni₃Ti) and γ"-Ni₃Nb precipitates in the interdendritic boundaries was evidenced in the deposition zone. The increase in laser scan speed to 600 m/min changed the microstructure from coarse to fine grains, and a further increase to maximum laser power of 1.75 kW showed the transformation to still finer dendritic structure. Even though the fine dendritic structure, it also resulted in delamination of bonding layers which could be deleterious. X-ray diffraction spectrum revealed the precipitation of γ-NiCr, γ'-Ni₃Al and γ"-Ni₃Nb in the γ-Ni matrix and there was no evidence for the transformation of γ"-Ni₃Nb to ς-Ni₃Nb. It indicated that the selected laser parameter had the least possibility of influence in the formation of intermetallics after treatment. The significant effect of grain refinement improved the hardness by 15–20 %. The tensile test on Inconel 718 showed the Ni₃Nb precipitate particles initiated the interfacial failure and was encountered with ductile mode of fracture.

11 illus, 5 tables, 30 ref

001068   RAO M C K, MALGHAN R L, ARUNKUMAR S, RAO S S, HERBERT M A (Computer Science Engineering Dep, Madanapalle Institue of Technology and Science, Madanapalle - 517 325, Email: rashmi.malghan@gmail.com) : An efficient approach to optimize wear behavior of cryogenic milling process of SS316 using regression analysis and particle swarm techniques. Trans Indian Inst Met 2019, 72(1), 191–204.

The present work is an endeavor to carry out a machining using LN₂ in face milling operations and to produce the milling samples with excellent wear resistance property. The output response (wear rate) depends on appropriate choice of speed, feed, and depth of cut. The experimental data are conducted (collected) for SS316 as per central composite design. The present work exemplifies an employment of conventional and nonconventional strategies for optimizing the milling factors of cryogenically treated samples in face milling to achieve the desired wear (response). The results of nonlinear regression (desirability strategy) and nonconventional [particle swarm optimization, (PSO)] optimization techniques are compared, and PSO is found to outperform the desirability function approach. The present work even highlights the effect and results of LN₂ on wear in contrast to wet condition.

10 illus, 8 tables, 32 ref

001083   SINGH S, SINGH R, GILL S S (Production Engineering Dep, Guru Nanak Dev Engineering Coll, Ludhiana, Punjab, Email: rupinderkhalsa@gmail.com) : Investigations for surface hardness of aluminum matrix composites with hybrid reinforcement. Trans Indian Inst Met 2019, 72(1), 181–90.

This work focuses on the investigations of hybrid reinforcement of SiC/Al2O₃ as dual particle size and triple particle size (TPS) on the surface hardness of hybrid aluminum matrix composite (AMC) prepared with synergistic combination of fused deposition modeling, vacuum molding (V) process and stir casting. It was observed that TPS-based SiC resulted into highest microhardness of 45HV. Further, ANOVA revealed that the percentage contribution of particle size and type of reinforcement on surface hardness of AMC were 27.30 % and 48.72 %, respectively. The best parametric setting (of input parameters) for microhardness is: particle size—TPS, type of reinforcement—SiC, vacuum pressure—350 mm of Hg, sand grain size—70 (AFS no.), vibration time—4 s. and composition/proportion of reinforcement in Al matrix— 10%, respectively, and overall, 5.1 % improvement in microhardness was observed at proposed parametric setting. The presence of Al₂O₃/SiC responsible for the improvement in microhardness was supported by photomicrographs.

7 illus, 6 tables, 28 ref

001042   MISHRA D K, MERAJ M, BADJENA S K, PAL S (Metallurgical and Materials Engineering Dep, National Institute of Technology Rourkela, Rourkela - 769 008, Email: pals@nitrkl.ac.in) : Dislocation interaction and v-shaped growth of the distorted structure during nanoindentation of Cu₂₀Ni₂₀Al₂₀Co₂₀Fe₂₀ (high-entropy alloy)-coated copper: A molecular dynamics simulation-based study. Trans Indian Inst Met 2019, 72(1), 167–80.

In this paper, the deformation behavior of Cu₂₀Ni₂₀Al₂₀Co₂₀Fe₂₀ high-entropy alloy-coated singlecrystal Cu substrate which undergoes nanoindentation has been investigated under molecular dynamic simulation with embedded-atom method potential. The dynamic structural evolutions under nanoindentation are presented using centrosymmetry parameter analysis, common neighbor analysis and radial distribution function plots. In the initial level of nanoindentation, the interface deformation is greatly confronted by the confined V-shaped growth of the distorted structure. But the sudden discrete dislocation burst account for avalanche break-down in the interface layer, which further get influenced by the evolution of multiple dislocation nodes that is significantly governed by core spreading, extended misfit dislocation generation and relative rotation. In the meanwhile, the subsequent generation of dislocation locks, complicated multiple dislocation loops, dislocation junctions and limited cross-slip in wide stacking faults (SFs) hasten the work hardening and in turn slows down the deformation progress. On the other hand, the intermediate appearance of narrow SFs and slip bands significantly reduces the work hardening rate that increases the optimum fracture strain value of the specimen. Moreover, the overall increase in dislocation density and dislocation length leads to a significant growth in dislocation sources which leads to forest hardening in the later stage.

12 illus, 109 ref

001032   MADHURI V, GOBINATH R, BALACHANDRAN G (JSW Steel Ltd, Salem - 636 453, Email: g.balachandran@jsw.in) : Effect of carbon on the microstructure and mechanical properties in wire rods used for the manufacture of cold heading quality steels. Trans Indian Inst Met 2019, 72(1), 155–66.

Wire rod is an intermediate product, used in the manufacture of cold head quality steel. The quality of the wire rod in the as-hot-rolled condition, was evaluated in a series of carbon steels with and without boron content and at two different wire rod thicknesses. While the effect of boron on hardenability in the hardened and tempered condition is well studied, the effect of boron on the quality in the ferrite–pearlite condition is not well analysed. Hence the present study established that the addition of boron improved strength and ductility in carbon steels compared to steels without boron. The increased strength was attributed to the increased pearlite content and fineness of interlamellar spacing, and the strength was compared with Gladman’s equation and a theoretical equation. The roomtemperature flow curve evaluation showed a higher strain hardening exponent in boron-containing steel compared to the steel without it. The upset ratio, which measured the ability of the wire rod for the subsequent wire drawing operation, was found to decrease with carbon content for steels without boron, while it was found to marginally increase in boron-containing steels. The evaluations were substantiated with microstructures evaluated in different grades and thicknesses.

9 illus, 5 tables, 11 ref

001098   WIBOWO H, ILMAN M N, ISWANTO P T, MUSLIH M R (Mechanical Engineering Education Dep, Yogyakarta State Univ, Yogyakarta, Indonesia, Email: heri_wb@uny.ac.id) : Reducing distortion and residual stress using dynamically controlled low stress no distortion and its influence on fatigue crack growth properties of steel welded joints. Trans Indian Inst Met 2019, 72(1), 143–53.

The need for reducing weld distortion and residual stress in welded thin plate structures has led to the development of stress-relieving methods. In-process welding technique using dynamically controlled low stress no distortion (DC-LSND) has been increasingly utilized for reducing distortion. The present investigation aims to study the effect of DC-LSND on distortion, residual stress, strength and fatigue crack growth behavior in steel weld joints. The DC-LSND treatments were carried out by quenching the weld metal region behind the welding torch using cryogenic liquid nitrogen. The sequence of tests was performed including distortion measurement, microstructure examination, hardness test, tensile test, residual stress measurement and fatigue crack growth test combined with SEM examination. Results showed that DC-LSND treatments reduced out-of-plane distortions accompanied by increasing strength and a hardness value of the weld joints and these improved mechanical properties are associated with weld microstructures. The modified DC-LSND treatment is most effective in reducing out-of-plane distortion. Another important finding in this research is that DCLSND treatments improve fatigue crack growth performance of the weld joints which could be related to weld residual stress.

15 illus, 3 tables, 24 ref

001059   PENG Y, CAI L, CHEN H, BAO C (Southwest Jiao Tong Univ, Chengdu- 610 031, China, Email: lix_cai@263.net) : A theoretical model for predicting uniaxial stress–strain relations of ductile materials by small disk experiments based on equivalent energy method. Trans Indian Inst Met 2019, 72(1), 133–41.

In this study, a constitutive relation parameters (CRP) model for mini-Brazilian disk (MBD) experiment and small punch testing (SPT) experiment have been put forward according to equivalent energy method, which can be expediently used to determine the uniaxial stress–strain relationships of ductile materials by small disks. Moreover, the ultimate tensile stress of ductile materials can be determined via a classical derivation. In order to verify the CRP model, lots of finite element analyses were carried out by ANSYS 14.5 based on the imaginary power-law stress– strain relations generating different elasticity modulus, yield stress and strain hardening exponent, and the results indicate that the stress–strain relations determined from MBD and SPT experiments by CRP model are in excellent agreement with the relations with inputs from FEA. Further, two kinds of experiments on P92 and DP600 were conducted, respectively, and the stress–strain relationships and the corresponding ultimate stress determined by CRP model were in accord with the standard tension results.

16 illus, 4 tables, 28 ref