003381   JOSHI K N, PATIL B T (Fr. Conceicao Rodrigues Coll of Engineering, Bandra, Mumbai) : Effect of illumination systems on statistical texture parameters based clustering and discrimination of machined surfaces using machine vision. Mapan - J Metrol Soc India 2019, 34(2), 197–205.

Inspection of surface quality using machine vision is based on the principle of surface characterization using texture parameters deduced from intensity values of images captured by the system. Illumination system plays significant role in deciding the performance and robustness of machine vision by controlling quality of image acquisition. This paper presents an experimental study of the effect of various illumination systems on image acquisition. Images of flat machined surfaces under five different illumination setups: ambient light, dark field, partial bright field with spotlight, partial bright field with tubelight and partial bright field with diffuse surface light; are grouped into three surface classes based on first and second order statistical texture parameters. The result showed that partial bright field with diffuse surface light provides maximum performance during image acquisition providing highest clustering accuracy. The images under this optimum setup are further analyzed using multiple discriminant analysis for determining the parameters significantly contributing to discrimination. The results showed that average height departure, root mean square, maximum peak to valley, skewness based on line samples; maximum peak to valley, skewness, kurtosis for surface and gray level co-occurrence matrix based contrast, correlation, energy, homogeneity effectively contributed to characterization of texture for discrimination.

32 ref

003352   ALI A, SI Q, YUAN J, SHEN C, YUAN S, CAO R (Jiangsu Univ, Zhenjiang, Jiangsu Province, China) : Experimental study of the performance characteristics, internal flow and noise characteristics of washing machine mini pimp under gas-liquid two-phase flow. Int J Multidiscip Res Dev 2019, 6(5), 69-73.

The upper drainage method is often used in drum type washing machines by using a miniature drainage pump. With the decrease in water level, the pump undergoes in the state of gas-liquid mixed transportation, empty discharge, at the end of drainage and produce unsteady flow. This unstable flow not only results in the deterioration of pump performance but also induces larger vibration and noise, which affects the quality of the equipment seriously. In order to explore the internal flow characteristics of the drainage pump during the empty discharge period, pump performance test was processed under pure water condition as well as under different air void fraction. The results show that head drop slowly with the increase of flow rate and the pump exhibits low efficiency. But the efficiency of the model pump is in good agreement with the value recommended by the manufacturer and the influence of gas on the drainage pump is smaller when the gas content is 1%. As the gas content increases, the slope of the flow-head descending curve becomes larger, and the influence of gas content on the pump performance increases with the increase of flow rate. Besides, the overall and local results of internal flow field and gas phase distribution are obtained and analyzed.

7 illus, 1 table, 16 ref

003358   CHIMI (Civil Engineering and Architecture Dep, Royal Univ of Bhutan, Phuentsholing, Bhutan) : Wastewater treatment in CST using DEWAT System. Int J Multidiscip Res Dev 2019, 6(5), 35-41.

With development of country and rapid increase in population, the demand for fresh water intakes has increased drastically. At the same time the production of kitchen and sewerage wastewater has increased proportionately. Therefore, the expenditure incurred due to fresh water supply and the disposal of wastewater has increased annually. Moreover, due to lack of proper wastewater treatment system, untreated wastewater has been discharged directly to the nearby environment polluting the environment and also posing the significant risk to the public health. Therefore these rapid urbanization has demanded for more sustainable and alternative methods of wastewater treatment system that can be implemented at a decentralized level besides the conventional and mechanized sewage treatment systems and septic tanks. This paper analysis the feasibility of Decentralized Wastewater Treatment System (DEWATS) to produce a highly efficient, viable, sustainable and eco-friendly, low cost solution for managing community wastewater in the hostel complex of the College of Science and Technology (CST) campus, Royal University of Bhutan.

5 illus, 6 tables, 30 ref

003623   SHEDEED H A, FARRAG B, ELWAKEEL E A, EL-HAMID I S A, EL-RAYES M A-H (Animal and Fish Production Dep, Alexandria Univ, Alexandria 21545, Egypt, Email: emankeel@yahoo.com) : Propolis supplementation improved productivity, oxidative status, and immune response of Barki ewes and lambs. Vet World 2019, 12(6), 834-43.

The present study was conducted to study the effect of propolis administration on bio-hematological parameters, antioxidant enzyme activities, and productivity of Barki ewes during late pregnancy and lactation under the arid conditions. Twenty-five pregnant Barki ewes were fed the basal diet (n=12, control) and the basal diet plus propolis (5 g/kg diet, n=13) for 1 month before parturition and continued 2 months after parturition. Milk yield and milk composition, hematological constituents, antioxidant enzyme activities, thyroid hormones, and lambs birth and weaning weights, and antioxidants were determined. Significant (p<0.05) increase in white blood cells in the propolis group compared to control was observed. Mean corpuscular hemoglobin (Hb) (MCH) and corpuscular Hb (MCH concentration %) were decreased (p<0.05) in propolis compared to control group. Milk yield was increased (p<0.05) in the propolis group compared with control and continued to increase with the advancement of lactation. Milk fat and milk total solids increased (p<0.05) in the propolis group than the control. Plasma immunoglobulin A (IgA) was increased (p<0.05) in propolis compared to control with no effect in IgM and IgG. Superoxide dismutase, hydrogen peroxide (HP), and nitric oxide were decreased (p<0.01) in the propolis group compared to control. Weaning weight for lambs born to ewes fed propolis was increased (p<0.05) at week 8 after birth compared with control lambs. Malondialdehyde and HP activities were decreased (p<0.01) in lambs born to propolis ewes compared to control. Crude Chinese propolis (5 g/d) supplementation improved milk yield, milk composition, and the antioxidant enzymes in Barki ewes and immune functions, growth performance and antioxidant status in their lambs under arid conditions.

5 illus, 6 tables, 47 ref

003422   UPPAL N, PAPPU A, PATIDAR R, GOWRI V S (Advanced Materials and Processes Research Institute, Bhopal 4620646, Email: gowrisorna@yahoo.com) : Synthesis and characterization of short sisal fibre polyester composites. Bull Mater Sci 2019, 42(3), 132.

Natural fibres have the potential to replace synthetic fibres for making polymer composites because of their good engineering properties. Sisal fibres obtained from the leaves of the sisal plant exhibit high strength among various other natural fibres, but have not been yet fully explored. Nevertheless, the impact of sisal fibre in polymer composites depends on sisal fibre extraction process, characteristic of fibre, fibre binder ratios, synthesizing technique, etc. In the present study, a detailed experimental protocol was conducted for sisal cultivation, fibre extraction, processing and development of composite boards/panels and assessed the impact of incorporation of chopped strand sisal fibre mat on the mechanical behaviour of polyester composites. The results revealed that the diameter of sisal fibre harvested after 5 years of its cultivation varied from 275 to 475µm with a tensile strength of 121–337 MPa; tensile modulus of 2.59–10.47 GPa; elongation at break varied from 3.37 to 10.86%. It is imperative to note that the mechanical properties of sisal composites significantly improved with the incorporation of chopped strand sisal fibre mat (preform). The tensile, flexural and impact strengths of composites developed using chopped short sisal fibre mat (preform) were 45.87 ± 3.2, 102.29 ± 9, 33,954 ± 5288 J m⁻², respectively. The findings of the study revealed the effectiveness of sisal fibre as reinforcing materials in polyester composites for use in building construction products and automotive applications.

9 illus, 2 tables, 42 ref

003350   AHMAD N, BHARATHAM H, HAMID Z A, PERIMAL E K, GEORGE P (Kebangsaan Malaysia Univ, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia, Email: hema@ukm.edu.my) : Functional performance evaluation of an alginate/nano-cockle shell powder nanobiocomposite bone scaffold with BMP-2. Bull Mater Sci 2019, 42(3), 130.

Improvement in bone tissue engineered scaffolds plays an important role in determining the healing outcome. This study aims to investigate the functional performance of previously developed nanobiocomposite bone scaffolds using bone morphogenetic protein-2 (BMP-2) for comparative analysis. The structural morphology and porosity of the scaffolds were analysed using scanning electron microscopy prior to dividing them into two groups, BMP-2 treated and control, for the surface mineralization study, in vitro and in vivo evaluation. The surface mineralization study showed the presence of plate-like calcium and phosphorus apatite crystallites in both groups indicative of the mineralization process. Osteoblasts (MC3T3-E1 subclone 4) cultured on the scaffold showed changes in the surface morphology with the presence of mineralization elements and the extensive presence of collagen fibres in BMP-2 scaffolds compared to the control. This was supported by a significant increase in calcium and alkaline phosphatase (ALP) activity showing enhancement in osteoconductiveness. In vivo studies conducted on 20 male ICR albino mice through subcutaneous dorsum implantation of scaffolds for 2 and 4 weeks showed a significant increase in the histological score for inflammatory cells, scaffold degradation and neovascularization at week 4 compared to week 2 for the BMP-2 scaffold. These findings are supported by a significant decrease in ALP activity indicative of scaffold mineralization. There were no significant differences between BMP-2 and control scaffolds within the period of this study. In conclusion, the functional performance of the scaffolds was mildly accelerated in BMP-2 compared to the control scaffold which showed promising properties in supporting osteogenesis without the use of any promoting factors.

11 illus, 1 table, 20 ref

003402   PHAIJIT S, SUKLUENG M, MARTHOSA S, NIYOMWAS S, VOO N Y, KUMAR A (Prince of Songkla Univ, HatYai, Songkhla 90110, Thailand, Email: montri.su@psu.ac.th) : A novel micro-solid oxide fuel cell (µ-SOFC) for detecting methane content in biogas. Bull Mater Sci 2019, 42(3), 129.

A novel micro-solid oxide fuel cell (µ-SOFC), with a rectangular saw-tooth shape, was designed with a 50 wt% BYCF + 50 wt% GDC₁₀ cathode and a 60 wt% NiO + 40 wt% GDC₁₀ anode deposited on a GDC₁₀ electrolyte substrate by the spray pyrolysis technique. µ-SOFC receives methane only (CH₄) as fuel gas from one side. The fuel gas was applied at a flow rate of 0.2 l min⁻¹. The power density obtained was 1.0 µW at 800◦C. Voltage levels generated by the µ-SOFC at 40–99.99% CH₄ was highly accurate representing the quantity of CH4. Low accuracy was observed at 10–30% of CH₄. Therefore, µ-SOFC is an application of SOFC technology to be a sensor for economically detecting CH₄ in a biogas system, while being capable of operating in humid conditions at high temperatures.

11 illus, 2 tables, 38 ref

003424   VANMATHI M, ISMAIL M M, KUMAR M S (B S Abdur Rahman Crescent Institute of Science and Technology, Chennai - 600 048, Email: vanmsen@yahoo.co.in) : Optimization of RF sputtering process parameters on electrical resistivity, deposition rate and sensitivity of Al-doped ZnO thin films grown on Si substrate using grey-Taguchi technique. Bull Mater Sci 2019, 42(3), 123.

Increasing environmental pollution globally demands gas sensors for monitoring urban air quality, fire and exhaust from automobiles. The need for high performance gas sensors requires a good control over sensing material structure. This paper studies the suitability of Al-doped ZnO thin films for development of CO gas sensors. Deposition of Al-doped ZnO thin films on Si substrates by the radio frequency sputtering technique was carried out to study the influence of process parameters. The process parameters selected for the analysis were power, deposition time, substrate temperature and working pressure. An orthogonal array L16 (4⁴), signal-to-noise ratio and analysis of variance (ANOVA) were performed to optimize the electrical resistivity, deposition rate and sensitivity of the thin films using the Taguchi method. Grey relational grade (GRG) was performed to obtain multiple-performance characteristics of the thin films by optimizing the process parameters. GRG analyses identified the process parameters: power 150 W, deposition time 35 min, substrate temperature 25^◦C and working pressure 1.5 Pa showed optimal multiple-performance characteristics. ANOVA analyses indicate that power and substrate temperature show significant effect compared with other parameters. Thin films at the annealing temperature (450^◦C) showed a decrease in electrical resistivity and an increase in sensitivity. At the sensor operating temperature of 150^◦C, Al-doped thin films exhibited the lowest resistivity 3.76 × 10⁻³ Ω-cm and the highest sensitivity of 59%. The optimal multiple-performance characteristic of thin film sample identified is found suitable for CO gas-sensing applications.

11 illus, 12 tables, 57 ref

003423   VANDANA B, SYAMALA P, VENUGOPAL D S, IMRAN SK S R K, VENKATESWARLU B, JAGANNATHAM M, KOLENCÍK M, RAMAKANTH I, DUMPALA R, SUNIL B R (Mechanical Engineering Dep, Bapatla Engineering Coll, Bapatla 522101, Email: bratnasunil@gmail.com) : Magnesium/fish bone derived hydroxyapatite composites by friction stir processing: Studies on mechanical behaviour and corrosion resistance. Bull Mater Sci 2019, 42(3), 122.

Magnesium (Mg)-based biomaterials are widely investigated for degradable implant applications. Developing Mg-based composites is one of the strategies adopted to increase the bioactivity and to reduce the degradation rate of Mg. In the present study, hydroxyapatite (fHA) has been produced from fish bones and incorporated into pure Mg sheets by friction stir processing (FSP). Microstructures of the composites clearly revealed the grain refinement in the stir zone up to 10 μm from the starting size of 2000 μm. Measurements of microhardness also indicated the effect of a smaller grain size and the presence of fHA on increasing the hardness in composites. Interestingly from the tensile tests, mechanical properties, such as yield strength and ultimate tensile strengths were measured as they decreased for the composite due to the presence of fHA particles. However, the observed % elongation of the composite was similar to that of a natural bone. From the electrochemical tests, the composite exhibited an enhanced corrosion performance. From the results, it can be concluded that the cost-effective Mg–fHA composites can be developed by FSP for degradable scaffold applications in biomedical fields.

9 illus, 3 tables, 53 ref

003385   KHUSHBOO, AZAD P (Electronics and Communication Engineering Dep, Maharaja Surajmal Institute of Technology, New Delhi 110058, Email: puneet.azad@msit.in) : A triboelectric energy harvester using human biomechanical motion for low power electronics. Bull Mater Sci 2019, 42(3), 121.

This article presents the conversion of human biomechanical motion into useful electricity using triboelectricity. Nylon, polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are selected as triboelectric materials for charge generation and aluminium/copper is selected as an electrode during vertical and sliding motions. Output voltage, energy density and power are computed across different capacitors and resistors. The maximum d.c. voltage is found to be 9.56 V across a 1 µF capacitor using a combination of nylon and PTFE during vertical motion. Also, the maximum energy density across a 100 µF capacitor is 492.47 µJ cm⁻³ and the maximum power across a 4.63 M resistor is 6.2 µW. Such portable systems can harvest human biomechanical energy while walking or exercising and can act as an infinite lifetime energy source for conventional low power electronics.

7 illus, 2 tables, 26 ref

003405   PUROHIT K, MURTY V V S, DIXIT R C, SHARMA A (Govt. Holkar Science Coll, Indore 452017, Email: kpurohit022@gmail.com) : Development of an acetanilide/benzoic acid eutectic phase change material based thermal energy storage unit for a passive water heating system. Bull Mater Sci 2019, 42(3), 119.

In the present work, two organic phase change materials (PCMs) are used to develop a new eutectic PCM for sharp melting point with high latent heat of fusion. Optimized eutectic can be suitable for a passive water heating system (PWHS). The binary eutectic PCMs consisting of different compositions of acetanilide and benzoic acid are prepared and optimized at a composition of 30:70 by weight percentage. Optimized samples are characterized by using differential scanning calorimetry (DSC), Fourier transform infrared spectrophotometry and field-emission scanning electron microscopy. The results of DSC showed that melting temperature and latent heat of the optimized eutectic PCM is found to be 75.56^◦C and 193.56 J g⁻¹. A negligible change in melting temperature and latent heat of fusion of the optimized eutectic based PCM after 100 accelerated heating and cooling cycles is observed. The prepared eutectic PCM is employed as a thermal energy storage (TES) system for PWHS. The experimental results of a eutectic PCM based TES system for the PWHS show that the use of eutectic helps in enhancing the maximum utility of solar energy during off-shine hours.

7 illus, 4 tables, 48 ref

003376   HASSANZADEH-AGHDAM M K, JAMALI J (Mechanical Engineering Dep, Ayandegan Institute of Higher Education, P.O. Box 76963, Tonekabon, Iran, Email: mk.hassanzadeh@gmail.com) : A new form of a Halpin–Tsai micromechanical model for characterizing the mechanical properties of carbon nanotube-reinforced polymer nanocomposites. Bull Mater Sci 2019, 42(3), 117.

In the present work, a new form of a Halpin–Tsai (H–T) micromechanical model is proposed to characterize the elastic modulus and tensile strength of carbon nanotube (CNT)-reinforced polymer nanocomposites. To this end, three critical factors, including random dispersion, non-straight shape and agglomerated state of the CNTs are appropriately incorporated into the H–T model. A comparison of the model predictions with some experiments on the CNT/polymer nanocomposites serves to verify the applicability of the proposed approach. It is found that the present predictions are in good agreement with the available experimental data. The results clearly reveal that for a more accurate prediction of the mechanical properties of the CNT/polymer nanocomposites, considering the random orientation, waviness and agglomeration of CNTs into the polymer matrix is critically essential. Also, some parametric studies are carried out to show the effects of volume fraction, non-straight shape, aspect ratio, mechanical characteristics and non-uniform dispersion of CNTs as well as matrix properties on the elastic modulus and tensile strength of CNT/polymer nanocomposites. The results reveal that it is necessary to eliminate the agglomeration and use the straight CNTs if the full potential of CNT reinforcement is to be realized.

9 illus, 58 ref

003362   EBADI S V, FAKHRALI A, SEMNANI D (Textile Engineering Dep, Isfahan Univ of Technology, Isfahan 845156-83111, Iran, Email: d_semnani@cc.iut.ac.ir) : Systematic investigation of parameters of an electrospinning process of poly(acrylic acid) nanofibres using response surface methodology. Bull Mater Sci 2019, 42(3), 115.

In this study, response surface methodology (RSM) based on the central composite design (CCD) was used for modelling the electrospinning process of polyacrylic acid (PAA) nanofibres, so as to assess simultaneously the effect of the most important electrospinning parameters (concentration of polymer solution, applied voltage, distance between the nozzle and collector and flow rate of solution) on the diameter of electrospun PAA nanofibres. The surface morphology was studied by scanning electron microscopy (SEM). The average diameter of PAA nanofibres obtained was from 233 to 1210 nm from SEM images with different process parameters. The results showed that the solution concentration, the applied voltage and the distance between the nozzle and collector are, in that order, the most important parameters affecting the diameter of nanofibres. The flow rate, however, showed no significant effect on the nanofiber diameter. The RSM model predicted that under optimal electrospinning conditions (solution concentration of 3 w/v %, voltage of 16 kV, electrospinning distance of 15 cm and flow rate of 1.75 ml h⁻¹), the nanofibres would be 262 nm in diameter, which was proved to be very close to the actual measured value. Therefore, the obtained results demonstrated the good performance of the RSM model in investigating the effect of electrospinning variables and predicting the diameter of PAA nanofibres. PAA nanofibres have great potential in applications such as sensors and biosensors, removal of heavy metals and contaminants, muscle tissue engineering, etc. and the use of thinner nanofibres leads to their improved performance in these applications.

7 illus, 3 tables, 49 ref

003388   LI R-S, LI F, XIN D-Q, LUO J-J, CHEN S, ZHANG Y (Xijing Univ, Xijing Road, Xi’an 710123, People’s Republic of China, Email: 20170213@xijing.edu.cn) : A molecular dynamics simulation of energetics and diffusion of point defects in a Au–Ag alloy. Bull Mater Sci 2019, 42(3), 113.

For revealing an aging mechanism for self-irradiation in a Pu–Ga alloy, we carried out a molecular dynamics (MD) simulation on a substitutional material, i.e., Au–Ag alloy. In this work, we estimate physical and microscopic properties of the Au–Ag alloy containing various point defects using a MD method, in particular, formation energy for point defects, migration energy for point defects diffusion into interstitial sites, and diffusion coefficient for the Au–Ag alloy containing point defects, such as vacancy, He atom and He-vacancy (He-V) cluster. The results indicate that volumetric heat capacity and linear expansion coefficient would decrease due to the various point defects, and He atom has the most remarkable influence on the physical properties of the Au–Ag alloy for point defects considered in this work. The formation energy of Au and Ag self-interstitial atom indicates that Octa1 is the most stable site, and structural stability of octahedral (Octa) interstitial sites for the He atom obeys Octa1 > Octa2 > Octa4 > Octa3. For the HenVm cluster, the formation energy of the defect structure is most stable at n = m. The diffusion coefficient of the He-V cluster is relatively smaller, showing that vacancy defects would further decrease atomic diffusion. An influence of various point defects on the diffusion velocity in the Au–Ag alloy obeys the He-V cluster > He > vacancy > Ag > Au.

11 illus, 10 tables, 28 ref

003407   RAJA D B P, RETNAM B S J (Aeronautical Engineering Dep, Noorul Islam Centre for Higher Education, Kanyakumari 629180, Email: binoaero87@gmail.com) : Effect of short fibre orientation on the mechanical characterization of a composite material-hybrid fibre reinforced polymer matrix. Bull Mater Sci 2019, 42(3), 111.

Polymer matrix composites (PMCs) are widely used materials in aerospace structures, boat hulls, automotive parts, etc. Since the progression of PMCs, a single fibre composite lags the addition of one or more fibres prepared as a hybrid composite which can be used to enhance their mechanical properties. Hybrid bamboo/glass fibres as the alternative replacement for polyester composites have been fabricated with ±60^◦ orientation, and coconut shell powder in micro and nanosized particles was added as the filler materials. Mechanical properties such as tensile, flexural, and impact strength, hardness number, and fatigue behaviour were investigated. The fractured surfaces of the composites were observed by scanning electron microscopy analysis. The test results reveal that the bamboo fibres in combination with glass fibres show an enhancement in their mechanical properties like strength and stiffness, and are suitable for aerospace applications.

13 illus, 1 table, 16 ref

003392   MALEK S, BAGHSHAHI S, SARRAF-MAMOORY R, NEMATI A (Materials Science and Engineering Dep, Imam Khomeini International Univ, Qazvin 3414896816, Iran, Email: baghshahi@eng.ikiu.ac.ir) : Gel combustion synthesis of fluorine-doped tin oxide and its characteristics: Applying D-optimal factorial design of experiment. Bull Mater Sci 2019, 42(3), 109.

Fluorine-doped tin oxide (FTO) nano-powders were synthesized by a gel combustion method. To analyse the effect of processing factors and their interactions and to achieve an equation for nano-powder particle size in terms of code factors, D-optimal factorial design was used. Stannous chloride penta-hydride, ammonium fluoride and citric acid were used to synthesize the FTO nano-powders. The structure, morphology and composition of the synthesized powders were characterized by X-ray diffraction, field emission scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The results revealed the formation of homogenous FTO nano-powders with an average particle size of 20 nm and equiaxed morphology in the concentration of precursor 0.2, citric acid to precursor molar ratio of 1 and pH of 0.5. The average particle size increased as the concentration of the precursor, citric acid to precursor molar ratio and pH increased from 0.2 to 1, 1 to 3 and 0.5 to 3, respectively. Citric acid to precursor molar ratio, concentration of the precursor and the pH had the most significant effect on the synthesis of the FTO nano-powders, respectively.

9 illus, 6 tables, 26 ref

003393   MEHRABI M, SHARIFPUR M, MEYER J P (Mechanical and Aeronautical Engineering Dep, Pretoria Univ, Pretoria 0002, South Africa, Email: mohsen.sharifpur@up.ac.za) : Electrical conductivity and pH modelling of magnesium oxide–ethylene glycol nanofluids. Bull Mater Sci 2019, 42(3), 108.

Nanofluids as new composite fluids have found their place as one of the attractive research areas. In recent years, research has increased on using nanofluids as alternative heat transfer fluids to improve the efficiency of thermal systems without increasing their size. Therefore, the examination and approval of different novel modelling techniques on nanofluid properties have made progress in this area. Stability of the nanofluids is still an important concern. Research studies on nanofluids have indicated that electrical conductivity and pH are two important properties that have key roles in the stability of the nanofluid. In the present work, three different sizes of magnesium oxide (MgO) nanoparticles of 20, 40 and 100 nm at different volume fractions up to 3 % of the base fluid of ethylene glycol (EG) were studied for pH and electrical conductivity modelling. The temperature of the nanofluids was between 20 and 70^◦C for modelling. A genetic algorithm polynomial neural network hybrid system and an adaptive neuro-fuzzy inference system approach have been utilized to predict the pH and the electrical conductivity of MgO–EG nanofluids based on an experimental data set.

8 illus, 5 tables, 31 ref

003408   RAMYA V, GANGWAR A, SHAW S K, MUKHOPADHYAY N K, PRASAD N K (Metallurgical Engineering Dep, Indian Institute of Technology (Banaras Hindu Univ), Varanasi - 221 005, Email: nandkp.met@iitbhu.ac.in) : Fe/Fe₃O₄ nanocomposite powders with giant high magnetization values by high energy ball milling. Bull Mater Sci 2019, 42(3), 93.

The present work reports on the relatively higher saturation magnetization values of Fe/Fe₃O₄ nanocomposites. For example, the nanocomposites of Fe obtained after milling for 10 h with 5, 10 and 15 wt % of Fe₃O₄ had displayed saturation magnetization values of 210, 238 and 216 Am² kg⁻¹, respectively, in contrast to 218 Am² kg⁻¹ of bulk Fe. Similarly, the maximum magnetization values for the nanocomposites after 20 and 30 h of milling were 215 and 190 Am² kg⁻¹ for the sample containing 5 and 15 wt % of Fe₃O₄, respectively. The values of HC and Mr suggest that nanocomposites exhibit soft ferromagnetic behaviour. The ball milling also reduced the crystallite and particle size of Fe from microndimension to nanometres. This was confirmed from X-ray diffraction, transmission electron microscopy and scanning electron microscopy analyses. The crystallite size of pure Fe decreased to 35, 20 and 19 nm, respectively, for the samples having 5, 10 and 15 wt% of Fe₃O₄ after 10 h of milling. The crystallite size decreased further with increased milling time.

8 illus, 1 table, 32 ref

003414   SAVAS S (Materials Science and Engineering Dep, Erciyes Univ, 38039 Melikgazi, Kayseri, Turkey, Email: ssavas@erciyes.edu.tr) : Effect of different parameters on the tribological performance of polypropylene/thermoplastic polyurethane blends under dry sliding conditions. Bull Mater Sci 2019, 42(3), 92.

In this study, polypropylene/thermoplastic polyurethane (PP/TPU) blends (weight ratios of 75/25 and 25/75) were produced by melt blending, and a maleic anhydride-grafted polypropylene (PP-g-MA) copolymer was used as a coupling agent. The effect of the concentration of the coupling agent (5–11 phr), TPU concentration (25–75 %), normal load (2–4 N) and sliding velocity (60–72 rpm) on the wear properties of the blends were characterized through a pin-on-disc abrasive wear test. A 2⁴ full-factorial experimental design was chosen to screen the significant factors and their interactions influencing the tribological performance of the blends. After the tests, the morphology of the worn surface of the samples was observed using scanning electron microscopy. Shore D hardness tests were also conducted and the relationships between these behaviours were analysed on the basis of the findings. According to the wear test results, the factors that have the greatest effect on the wear rates are as follows: normal load, TPU concentration, sliding velocity and PP-g-MA concentration, respectively. The wear rate of the blends increases by increasing the normal load, TPU concentration and sliding speed, and slightly decreases by increasing the PP-g-MA concentration. As expected, the wear and hardness results showed the apparent superiority of the PP₇₅/TPU₂₅ blends over the PP₂₅/TPU₇₅ blends, because of the higher content of rigid segments in the blends.

7 illus, 4 tables, 30 ref

003372   GÜLLÜ H H (Electrical and Electronics Engineering Dep, Atilim Univ, Ankara 06830, Turkey, Email: hasan.gullu@atilim.edu.tr) : Investigation of electrical properties of In/ZnIn₂Te₄/n-Si/Ag diode. Bull Mater Sci 2019, 42(3), 89.

In/ZnIn₂Te₄/n-Si/Ag diode structure was fabricated by the thermal deposition of a ZnIn₂Te₄ thin film on n-Si wafer substrate with Ag metal back contact. The structural characteristics of the film were investigated in terms of composition, X-ray diffraction and topographic measurements. The diode structure was completed by evaporating In metal on the film surface as a top contact. The diode parameters as saturation current, barrier height, ideality factor and series resistance values were determined from the semi-logarithmic forward bias current–voltage characteristics of the diode. According to the assumption of the thermionic emission model, the ideality factor was found higher than unity and it was also observed that the barrier height and ideality factor showed a temperature-dependent profile resulting from the nonideality in the current–voltage behaviour of the diode. As a result, the model was modified by considering inhomogeneous barrier formation and Gaussian distribution was expected to be dominant on 1.37 eV mean barrier height with a deviation of 0.18. In addition, the voltage dependence of these Gaussian diode parameters was investigated. The forward and reverse bias capacitance and conductance measurements showed that there was a slight change in capacitance values with frequency whereas the conductance values decreased with increase in frequency. In addition to the current–voltage analysis, the distribution of density of interface states and the values of series resistance were evaluated as a function of bias voltage and frequency.

9 illus, 1 table, 54 ref

003395   NGUYEN T-T, DUONG Q-D (Le Quy Don Technical Univ, Ha Noi 100000, Viet Nam, Email: trungthanhk21@mta.edu.vn) : Optimization of WEDM process of mould material using Kriging model to improve technological performances. Sadhana 2019, 44(6), 154.

Improving the technical performance of the wire electro-discharge machining (WEDM) process is an effective solution to decrease manufacturing costs. This paper addresses a multi-response optimization to simultaneously improve the cutting area rate CAR and decrease the kerf width AKW, while the average surface roughness ASR is predefined as a constraint. The processing conditions considered include the pulse-on time T_on, the current I, the voltage V and the wire speed S. A WEDM machine was adopted in conjunction with the Box– Behnken matrix to conduct experimental trials for machining of SKD61 steel. Highly nonlinear relationships between machining parameters and technological outputs were developed using the Kriging models. Finally, an archive-based micro-genetic algorithm (AMGA) was used to resolve the trade-off analysis among three responses and determine the optimal values of the processing factors. The results showed that a set of feasible solutions can be determined for the low kerf width as well as the surface roughness and the high cutting area rate. The selection of optimum parameters could help the WEDM operators to save the machining costs and time. The combination of the Kriging model and AMGA could be considered as an intelligent approach for modelling WEDM processes and predicting optimal results.

10 illus, 7 tables, 35 ref

003351   ALAM M P, SINHA A N (Mechanical Engineering Dep, National Institute of Technology Patna, Ashok Rajpath - 800 005, Patna, Email: parwez.me13@nitp.ac.in) : Fabrication of third generation Al–Li alloy by friction stir welding: A review. Sadhana 2019, 44(6), 153.

Aerospace industry stimulates research for new materials to reduce the weight of it thereby reduction of fuel consumption. Aluminium–Lithium alloys have become a good alternative due to its inherent properties. Nevertheless, joining of these materials by traditional welding is difficult. Friction stir welding process considered as an ideal joining process for these materials due to low heat input. This paper reviews the fabrication of the latest generation of Al–Li alloy by friction stir welding. In addition, it also presents and discusses the effect of process parameters on microstructure, mechanical properties and precipitate distribution in friction stir welded joint of Al–Li alloy.

10 illus, 3 tables, 111 ref

003367   ERSOY H V (Mechanical Engineering Dep, Yildiz Technical Univ, 34349 Istanbul, Turkey, Email: ersoyhv@yahoo.com) : Effect of magnetic field on the time-dependent flow due to a disk with non-torsional oscillation and a Newtonian fluid at infinity rotating about distinct axes. Sadhana 2019, 44(6), 152.

This work aims to study the effect of magnetic field on the time-dependent flow of an insulated disk executing non-torsional oscillation in its own plane and a Newtonian fluid at infinity while they are initially rotating at the same speed about two vertical axes. It is shown that the presence of a magnetic field causes a resistive force and the required time to reach the periodic state becomes shorter. Further, it is demonstrated that there is an excellent agreement between the exact solution that is appropriate for all values of time and the periodic solution that is valid after the periodicity of the flow starts.

4 illus, 12 ref

003356   CHAKRABORTY S S, DUTTA S (CSIR-Central Mechanical Engineering Research Institute, Durgapur - 713 209, Email: ss.chakraborty@cmeri.res.in) : Estimation of dilution in laser cladding based on energy balance approach using regression analysis. Sadhana 2019, 44(6), 150.

Laser cladding is a complex manufacturing process involving more than 19 variables related to laser source, workpiece movement, powder-substrate material combinations, clad geometry, powder flow dynamics, shrouding gas flow and so on. Significant research efforts have been directed to analytical-numericalempirical modelling of laser cladding and also in-process monitoring and control of the process. Still, due to complicated physics there is a dearth of simple analytical model for estimation of dilution in laser cladding. Its experimental measurement requires suitable micrographs of the clad cross section perpendicular to the clad path. This is a time-consuming and destructive way of measurement. Numerical models are time consuming to evaluate and hence not suitable for fast decision making or real-time control implementation. The analytical models available, despite having many approximations, are a little complicated, require fair amount computer programming and often need suitable prior guessing of range of output parameters for adjustment of constant values in the models. This poses some challenges for use and having an intuitive guidance, for a beginner/ unskilled operator. Besides, their complexity may erect barrier in the way of their implementation for real time monitoring and control. This work proposes a simple linear regression model, formed based on energy balance approach, to estimate dilution in laser cladding. After fitting to a set of data, within a suitable process parameterwindow, for a particular clad-substrate material combination, this model can estimate dilution as a function of input/easily measureable parameters, viz. laser power, scan speed, clad width and clad height. The model fitted well to the experimental data taken from literature.

2 illus, 2 tables, 21 ref

003379   JOS B C, HARIMANIKANDAN M, RAJENDRAN C, ZIEGLER H (Management Studies Dep, Indian Institute of Technology Madras, Chennai - 600 036, Email: bobincherian@gmail.com) : Minimum cost berth allocation problem in maritime logistics: New mixed integer programming models. Sadhana 2019, 44(6), 149.

The berth allocation problem (BAP) involves decisions on how to allocate the berth space and to sequence maritime vessels that are to be loaded and unloaded at a container terminal involved in the maritime logistics. As the berth is a critical resource in a container terminal, an effective use of it is highly essential to have efficient berthing and servicing of vessels, and to optimize the associated costs. This study focuses on the minimum cost berth allocation problem (MCBAP) at a container terminal where the maritime vessels arrive dynamically. The objective comprises the waiting time penalty, tardiness penalty, handling cost and benefit of early service completion of vessels. This paper proposes three computationally efficient mixed integer linear programming (MILP) models for the MCBAP. Through numerical experiments, the proposed MILP models are compared to an existing model in the literature to evaluate their computational performance. The computational study with problem instances of various problem characteristics demonstrates the computational efficiency of the proposed models.

4 tables, 21 ref

003371   GIRISHA V A, JOSHI M M, KIRTHAN L J, BHARATISH A, HEGDE R (Mechanical Engineering Dep, RV Coll of Engineering, Bengaluru 560 059, Email: bharatisha@rvce.edu.in) : Thermal fatigue analysis of H13 steel die adopted in pressure-die-casting process. Sadhana 2019, 44(6), 148.

The thermal fatigue of die casting die steels causes reduction in tool life and seriously affects the surface conditions such as microstructure, hardness, surface finish and residual stresses. The improvement of die life by suitably modifying the die design assumes utmost importance for die designers. In this regard, a key issue is the size and location of cooling channels relative to the surface of the die, which affect the thermal stresses and fatigue life of dies. This paper focuses on thermal fatigue analysis of pressure-die-casting die steel H13 and analyses the effect of coolant channel location on temperature distribution and fatigue parameters such as life, damage, equivalent alternating stress and biaxiality using ANSYS Workbench 15.0 finite-element package. Increase in wall thickness (location of coolant channel from base) caused an increase in temperature and decrease in die life, which led to increase in volume porosity and hence crack initiation. The optimum coolant channel location from the base is obtained as 1 mm, which corresponds to minimum normal stress of 149.1 MPa, fatigue life of 4.1 x 10⁵ cycles, fatigue damage of 2436.9 and equivalent alternating stress of 100.62 MPa.

13 illus, 3 tables, 18 ref

003420   THILLAINAYAGI R, KUMAR K S (Aerospace Engineering Dep, Anna Univ, Chennai 600044, Email: thillaimit@gmail.com) : Hybrid bi-dimensional empirical mode decomposition based enhancement technique for extreme low contrast UAV thermal images. Sadhana 2019, 44(6), 147.

The performance of automatic target detection and classification systems are typically affected by reduced contrast quality introduced by external interferences. In particular for Unmanned Aerial Vehicle (UAV) captured thermal surveillance images, the effect is more evident. This advises the use of contrast enhancement technique as a solution to enhance the reduced contrast of hot regions for efficient target detection. In this paper, a simple and novel enhancement technique based on singular value decomposition (SVD) using Bi-Dimensional Empirical Mode Decomposition (BEMD) is proposed to enhance the hot regions in extreme low contrast thermal images captured by UAV. In the first step, the technique decomposes the thermal image into Intrinsic Mode Functions (IMFs) and residue by using BEMD. In the second step, it applies Contrast Limited Adaptive Histogram Equalization (CLAHE) in the residue for local contrast enhancement and then calculates the singular value matrix. In the third step, residue component is rescaled for further improvement of hot regions using scaling factor. In the fourth step, a detail enhanced IMF components are generated using gray scale transformation. Finally, the contrast enhanced residue undergoes Inverse BEMD (IBEMD) together with the detailed enhanced IMFs for enhanced image generation. Experimental results demonstrate that the proposed technique effectively enhances the contrast and details in the image with less visual artefacts than other state-of-the-art techniques.

8 illus, 4 tables, 26 ref

003389   LIAO Y, LI H (Electronic Science and Technology of China Univ, Chengdu, China, Email: lhm3551@qq.com) : Deep echo state network with reservoirs of multiple activation functions for time-series prediction. Sadhana 2019, 44(6), 146.

In this paper, an improved deep echo state network is proposed, named as multiple activation functions deep echo state network (MAF-DESN), where states are activated by multiple activation functions. A sufficient condition for MAF-DESN is given to guarantee that MAF-DESN possesses the echo state property. Finally, the MAF-DESN is applied to chaotic time-series predictions and compared to other ESN deformation models and popular LSTM. Simulation results show that under same network size condition, MAF-DESN possesses stronger explanatory power in chaotic far-infrared laser predictions (R-square=0.9537, others≤0.6487), and better fitting ability in daily foreign exchange rates (MAE=0.0040, others≥0.0047) and chaotic far-infrared laser (MAE=3.4042, others≥4.9021). In high-dimension-input task, MAF-DESN improved the performance when the results were compared (R-square=0.4274, others≤0.3975 and MAE=5.2221, others≥7.6876), while the train time of MAF-DESN did not increase when compared to DESN.

10 illus, 5 tables, 30 ref

003386   KUMAR M, GAUTAM S S, DIXIT P M (Mechanical Engineering Dep, Dr. B R Ambedkar National Institute of Technology, Jalandhar 144011, Email: kumarm@nitj.ac.in) : A non-linear ductile damage growth law at elevated temperature. Sadhana 2019, 44(6), 145.

Continuum damage mechanics (CDM) model is commonly used for the prediction of ductile fracture. For numerical simulation of ductile fracture in impact or high-temperature problems, the damage growth law that incorporates the effect of high temperature is needed. Experimentally, it has been observed that damage growth decreases with temperature. However, the damage growth law at high temperature is not easily available in the literature. In the present work, a damage growth law at high temperature is proposed for steel, based on the experimental measurement of damage carried out at IIT Kanpur.

30 illus, 17 tables, 28 ref

003391   LOU Z, WANG X, WANG Y, WANG X, XU C, WANG Z (Dalian Univ of Technology, Dalian 116023, Liaoning, China, Email: louzf@dlut.edu.cn) : Precision assembly method of a kind of small interference fitting parts. Sadhana 2019, 44(6), 144.

Interference fitting parts are widely used in many engineering applications. Press-fit method is commonly used for assembling interference fitting parts, but most of press-fit instruments cannot meet assembly requirements of small precision parts for poor accuracies of positioning, alignment and pressing displacement’s measurement. In this paper, the press-fit method of a kind of small precision interference fitting parts was introduced. In order to achieve a reasonable assembly of the interference fitting parts, the influence of aligning error and positioning error on assembly accuracies were analyzed by finite element method (FEM). Furthermore, the relation between pressing force and displacement were also analyzed to obtain a reasonable range of force–displacement curves, which can be used for assembly quality estimation. An automatic press-fit instrument was developed. Through analyzing relation between pressing force and the instrument’s elastic deformation, press-fit displacement error was compensated to increase assembly accuracy. A kind of machine vision device with upper and lower CCDs was used to detect relative situation of parts, and calibration method of the machine vision device was proposed. The assembly experiments showed that press-fit force–displacement curve was consistent with the predicted values. The parts’ relative position deviation was less than ±5 μm, and parallelism deviation was less than 10 μm, which meet the requirements of the assembly accuracy index.

32 illus, 6 tables, 15 ref

003416   SINGH G, SINGH R, SINGH S (Production Engineering Dep, Guru Nanak Dev Engineering Coll, Ludhiana - 141 006, Email: rupindersingh78@yahoo.com) : Partial dentures by centrifugal casting assisted by additive manufacturing. Sadhana 2019, 44(6), 143.

This research work focuses on preparation of partial dentures (as functional prototypes) by additive manufacturing (AM)-assisted centrifugal casting (CC). The master pattern for partial dentures was prepared on fused deposition modelling (FDM) set-up (established by AM technique at low cost). The final dentures as functional prototypes were prepared with a nickel–chromium (Ni–Cr)-based alloy by varying different proportions of Ni% (N) by weight %. The other input parameters were powder to water P/W ratio (W) and pH value (H) of water used for mixing the investment. The samples prepared were ascertained for dimensional deviation (Δd), surface finish (R_a) and micro-hardness (HV) as output parameters. Finally, multifactor optimization has been applied on output parameters of functional prototypes prepared. This study highlights that partial denture prepared with W-100/15, H-7 and N-61 % gives overall better results from mechanical properties and dimensional accuracy viewpoint. The results are also supported by photo-micrographic analysis.

8 illus, 10 tables, 42 ref

003400   PARIDA A K, MAITY K (Mechanical Engineering Dep, Indian Institute of Technology Delhi, Delhi, Email: asitzone4@gmail.com) : Hot machining of Ti–6Al–4V: FE analysis and experimental validation. Sadhana 2019, 44(6), 142.

Machining process is a nonlinear process where high stress, temperature and strain are generated in the primary and secondary shear zone. It is difficult to determine these parameters experimentally and also consumes time. In this study, finite-element method (FEM) is applied to hot machining of Ti–6Al–4V alloy using DEFORM software. The simulations are used to investigate the effect of heating temperature on cutting force, cutting temperature, stress, strain and chip morphology for various machining conditions. The predicted results are compared to results obtained in room temperature and hot machining conditions. From this analysis, it is observed that hot machining reduces the cutting force, and changes the chip morphology. To validate the simulation results, an experimental trial is performed and positive coherence is achieved.

12 illus, 1 table, 21 ref

003360   DHAKA A, CHAUHAN S, BHASKAR V, NANDAL A (Electrical Engineering Dep, Northwestern Polytechnic Univ, 47671 Westinghouse Drive, Fremont, CA 94539, USA, Email: vcharan@gmail.com) : Improving bounds on outage probability in correlated Rayleigh fading environment. Sadhana 2019, 44(6), 140.

In this letter, we propose a limiting criterion to improve the bounds on outage probability for n-correlated Rayleigh fading channel. We use a threshold-based limiting distribution to yield explicit bounds on probability. This work takes into consideration the effect of correlated noise signal to the receiver, which is a generalization based on the power and noise correlation vectors. The approach proposed in this paper is different from many other existing bounds and it provides strong information to improve the results for the bounds on the outage probability.

2 illus, 15 ref

003361   DOMINIC S, JACOB L (Electronics and Communication Engineering Dep, National Institute of Technology Calicut, Kozhikode - 673 601, Email: susandominic89@gmail.com) : Distributed interference-aware admission control and resource allocation for underlaying D2D communications in cellular networks. Sadhana 2019, 44(6), 138.

In this letter, we present a two-phase distributed resource allocation algorithm for a Device-toDevice (D2D) network underlaying a cellular network. In the first phase, D2D pairs learn resource block (RB) of the cellular user equipment (CUEs) to be used, while playing an interference minimization game. Each D2D pair is ensured an interference below an upper limit, which is chosen as the criterion for admission control. In the next phase, power allocation for the device pairs allocated to each RB is carried out to maximize their sum rate while ensuring a minimum rate to the CUEs using a pricing scheme. We perform simulations to evaluate the performance of the proposed scheme.

2 illus, 2 tables, 7 ref

003354   BHAT K G, LAXMINIDHI T, BHAT M S (Electronics and Communication Engineering Dep, National Institute of Technology Karnataka, Surathkal - 575 025, Email: kalpanabhat_ec@nitk.ac.in) : A compact 4-to-8-bit nonbinary SAR ADC based on 2 bits per cycle DAC architecture. Sadhana 2019, 44(6), 137.

A compact programmable-resolution successive approximation register (SAR) analog to digital converter (ADC) for biosignal acquisition system is presented. The ADC features a programmable 4-to-8-bit DAC that makes the ADC programmable with 2 bits evaluated in each clock cycle. At low resolution with relaxed noise and linearity requirements, use of an increased clock speed improves energy efficiency. A single DAC architecture is used to generate references for 2 bits per cycle evaluation for all resolutions. Nonbinary switched capacitor circuits, least sensitive to parasitics, are proposed for the use in DAC for reference generation. The choice of architecture and circuit design are presented with mathematical analysis. The post-layout simulation of designed ADC in 90 nm CMOS process has 1.2 MS/s sampling rate at 8-bit mode with a power consumption of 185 μW achieving an ENOB of 7.6. The active area of designed ADC is 0.06 mm² . The DAC resolution scaling and the use of variable sampling rate maximize efficiency at lower resolutions. Therefore, figure of merit (FOM) is degraded only by a factor of 4.7 for resolution scaling from 8 to 4 bits. This is a significant improvement over 16 x degradation expected from 8-bit to 4-bit resolution scaling by truncating the bits.

24 illus, 6 tables, 17 ref

003413   SAJID M, SADIQ M N, MAHMOOD K, ALI N (National Univ of Sciences and Technology, H-12, Islamabad, Pakistan, Email: noveelsheikh@gmail.com) : A Legendre wavelet spectral collocation method for analysis of thermal radiation and slip in the oblique stagnation-point flow of Walters-B liquid towards a stretching surface. Sadhana 2019, 44(6), 136.

A spectral collocation method based on Legendre wavelet is applied to analyse the slip and radiation effects in the flow of an elastico-viscous Walters-B fluid. The fluid is assumed to impinge obliquely on a stretching surface with linear stretching velocity. The governing system of equations is converted into dimensionless ordinary differential equations by invoking suitable similarity variables. The proposed iterative spectral technique for solving governing system of initial value problems is applied for obtaining the solutions. First, we extend Legendre wavelet and Legendre–Guass collocation points are computed for a large interval. The differential equations are converted into a system of algebraic equations. The approximate solution is obtained by solving these algebraic equations. The proposed algorithm is implemented to obtain numerical results for different values of the pertinent parameters. The proposed algorithm controlled the overshooting and undershooting in velocity profiles. The presence of stretching and slip enhances the velocity and reduces the temperature of the fluid within the boundary layer.

14 illus, 3 tables, 35 ref

003373   HABBU S, DALE M, GHONGADE R (Electronics and Telecommunication Dep, Vishwakarma Institute of Information Technology, Pune, Maharashtra, Email: mpdale@mescoepune.org) : Estimation of blood glucose by non-invasive method using photoplethysmography. Sadhana 2019, 44(6), 135.

This paper presents a system which estimates blood glucose level (BGL) by non-invasive method using Photoplethysmography (PPG). Previous studies have shown better estimation of blood glucose level using an optical sensor. An optical sensor based data acquisition system is built and the PPG signal of the subjects is recorded. The main contribution of this paper is exploring various features of a PPG signal using Single Pulse Analysis technique for effective estimation of BGL values. A PPG data of 611 individuals is recorded over duration of 3 minutes each. BGL value estimation is performed using two types of feature sets, (i) Time and frequency domain features and (ii) Single Pulse Analysis (SPA). Neural network is trained using above mentioned proposed feature sets and BGL value estimation is performed. First we validate our methodology using the same features used by Monte Moreno in his earlier work. The experimentation is performed on our own dataset. We obtained comparable results of BGL value estimation as compared with Monte Moreno, with maximum R² = 0.81. Further, BGL estimation using (i) Time and frequency domain features and (ii) Single Pulse Analysis (SPA) is performed and the resulting coefficient of determination (i.e., R² ) obtained for reference vs. prediction are 0.84 and 0.91, respectively. Clarke Error Grid analysis for BGL estimation is clinically accepted, so we performed similar analysis. Using Time and frequency domain feature set, the distributions of data samples is obtained as 80.6 % in class A and 17.4 % in class B. 1 % samples in zone C and Zone D. For Single Pulse Analysis technique (SPA) the distribution of data samples are 83 % in class A and 17 % in class B. The proposed features in SPA have shown significant improvement in R² and Clarke Error grid analysis. SPA technique with the proposed feature set is a good choice for the implementation of system for measurement of non-invasive glucometer.

15 illus, 4 tables, 32 ref

003401   PATTNAIK S, DHALIWAL B S, PATTNAIK S S (IKG Punjab Technical Univ, Jalandhar, Punjab, Email: sumanbhagat1199@gmail.com) : Impact analysis of mobile phone electromagnetic radiations on human electroencephalogram. Sadhana 2019, 44(6), 134.

The experimental study of electromagnetic interference of mobile phone radiations on brain waves is a contemporary research area and the ever-increasing use of mobile phones make it more imperative to explore the problem area in detail. Electromagnetic signal from mobile phones operating in Global System for Mobile (GSM) and wide band code division multiple access (WCDMA), has been considered in this paper and their interference impacts have been analyzed on the human electroencephalogram (EEG). The impact on brain waves i.e., delta, theta, alpha, beta and gamma waves are analyzed in five modes namely ideal mode i.e., when mobile phone is not in use, transmission mode and the receiving modes of second generation (2G) and third generation (3G) networks. The data has been acquired from 75 young and healthy students of a post graduate institute while the students were making their routine calls. The acquired EEG signal is analyzed using various parameters viz.; Approximate Entropy(ApEn), Largest Lyapunov Exponent (LLE), Hurst Exponent (HE), Correlation dimension (CD) and the power of the brain waves have also been analyzed. It has been found that due to mobile phone usage, there is variation in the nonlinear parameters and increase in the power of the alpha brain waves at T5O1 during 3GRx and decrease in alpha power at the P4O2 channel in all modes. It has been observed that the change at the right temporal region is more, the side to which mobile phone was held. The Statistical analysis has also been done using SPSS software which shows significant variations at some of the channels in different modes.

10 illus, 9 tables, 45 ref

003409   RANA A, DONGRE G, JOSHI S S (Mechanical Engineering Dep, Indian Institute of Technology Bombay, Mumbai - 400 076, Email: ssjoshi@iitb.ac.in) : Analytical modeling of exit Burr in drilling of Ti6Al4V alloy. Sadhana 2019, 44(6), 133.

Burrs affect precision components and cause assembly related problems, and in general, decrease manufacturing productivity. Drilling burr formation involves multiple stages that are influenced by variation in thrust forces, temperature, stress conditions, and deformation modes in the unsupported length of the workmaterial below the drill. Several of these have not been adequately investigated so far. Therefore, the objective of this work is to model the complex phenomena that occur just before the exit of the drill tip from the bottom surface of the hole, and up to the complete exit of the drill point from the work surface. Accordingly, two models have been developed: (i) to estimate onset of bending in conjunction with theory of plasticity, which leads to the formation of a small drill cap under the pressure of steady-state drilling thrust forces, and (ii) to evaluate exit burr size that involves stretching and bending of a thin layer below the drill tip, using the principle of energy conservation. It is observed that a fracture is initiated at the chisel edge corner resulting in the formation of a small drill cap. The exit burr size predicted by the model is within one standard deviation from the average burr height as determined from the experimental data.

15 illus, 3 tables, 35 ref

003394   NADH B P, MADHAV B T P, KUMAR M S (Electronics and Communication Engineering Dep, Antennas and Liquid Crystals Research Centre, Guntur, Email: btpmadhav@kluniversity.in) : Design and analysis of dual band implantable DGS antenna for medical applications. Sadhana 2019, 44(6), 131.

An implantable antenna is designed for body area network, industrial scientific and medical applications with low specific absorption rate (SAR). The proposed antenna with defected ground structure (DGS) is designed on the FR4 substrate as well as on polyimide substrate. The designed antenna providing dual band characteristics at (Industrial scientific and medical) ISM band of 2.5 GHz and location application for emergency services (LAES) band at 4.2 GHz. The electromagnetic radiation is evaluated using the specific absorption rate in three layered phantom models and the SAR values of the antenna are evaluated by placing the antenna at different levels. The antenna distance is varied inside the skin layer to 5 mm away from the threelayered model and observed the reduction in SAR, when moving away from skin tissue. The observed value of SAR satisfies the IEEE-C95-1-2005 standards at ISM operating band. The proposed antenna is tested on threelayered phantom model in simulation through HFSS and in the real time on artificial layers with the help of combinational analyzer (CNA) connection.

16 illus, 4 tables, 26 ref

003421   UKKEN M G, SIVAPRAGASAM A (M S Ramaiah Univ of Applied Sciences, Bangalore 560 058, Email: sivapragasam.aae.et@msruas.ac.in) : Aerodynamic shape optimization of airfoils at ultra-low Reynolds numbers. Sadhana 2019, 44(6), 130.

The flow over NACA 0008 airfoil is studied computationally in the ultra-low Reynolds number regime Re ∈ [1000, 10000] for various angles of attack α ∈ [0, 8]. The laminar flow separation occurs even at low angles of attack in this Reynolds number regime. The lift curve slope is far reduced from the inviscid thin airfoil theory value of C_l,α = 2π. Significant increase in the values of drag coefficient is seen with a decrease in Re. Lift-to-drag ratios are consequently very low. An adjoint-based aerodynamic shape optimization methodology is employed to obtain improved aerodynamic characteristics in the ultra-low Re regime. Three different objective functions are considered, namely, (i) minimization of drag coefficient, C_d, (ii) maximization of lift coefficient, C_l, and (iii) maximization of lift-to-drag ratio, (C_l/C_d). Significant improvement in each of the objective functions is obtained.

21 illus, 2 tables, 35 ref

003415   SEKAR K (Mechanical Engineering Dep, National Institute of Technology Calicut, Calicut - 673601, Email: sekar@nitc.ac.in) : Mechanical and tribological properties of Al7475-SiCp composites by stir casting method and wear rate modeling using RSM. Sadhana 2019, 44(5), 129.

The microstructure, mechanical and wear properties of the Al 7475-SiCp composites and to investigate the effects of SiC micro-particles reinforcement with alloy have been studied. Al 7475-SiCp composites have been developed by a stir casting method. The SiCp size in the range of 15–40 lm with weight.% of 0, 5, 10 and 15 were injected in molten Aluminum 7475 alloy in argon gas environment and stirrer using a mechanical method at 450 rpm to ensure uniform distribution of SiC particles. The mechanical properties such as hardness and compressive strength of the composites were found to be gradually improved with the addition of 5–15% SiCp reinforcement. The ultimate tensile and impact strength increased with 10% of SiCp reinforcement. For modeling the wear rate, the experiments were conducted in Pin-on Disc tribometer at room condition. A three-level central composite design with response surface methodology was used to reduce the experimental conditions and to predict the abrasive response of wear rate through the development of mathematical models. The model developed is efficiently predicted the rate of wear at 95% confidence level and the entire model validate with analysis of variance.

11 illus, 5 tables, 17 ref

003396   NIVITHA M R, ROY N, KRISHNAN J M (Civil Engineering Dep, Indian Institute of Technology Madras, Chennai, Email: jmk@iitm.ac.in) : Influence of refinery processing methods on ageing of bitumen. Sadhana 2019, 44(5), 128.

This investigation reports the influence of processing condition (air rectification and component blending) on ageing and stress relaxation behaviour in bitumen. FTIR spectra were recorded on two samples of bitumen at unaged, short-term aged and long-term aged conditions. Indices such as aliphaticity, aromaticity, carbonyl and sulphoxide calculated from the FTIR spectra were used in the analysis. It was seen that the ageing compounds in the air-rectified bitumen were higher at the end of the production process compared with the blended bitumen while the rate of oxidation compounds formed during short-term and long-term ageing was higher in the blended bitumen. In addition, a stress relaxation test was performed at 25 ^oC in the unaged, shortterm and long-term ageing conditions. Since the formation of ageing compounds leads to change in ‘stiffness’ and hence a change in the stress relaxation behaviour of the material, it is seen that the stress relaxation results are in line with the material behaviour as seen from the FTIR tests.

11 illus, 3 tables, 31 ref

003377   INAL S, ERKAN I, AYDINER K (Mining Engineering Dep, Gumushane Univ, Gumushane, Turkey, Email: ilkererkan@gumushane.edu.tr) : Determination of the wear performance of diamond saw blades using inductively coupled plasma. Sadhana 2019, 44(5), 127.

Saw blades are one of the most used cutting tools. They compose the expensive parts of a cutting machine. Therefore, saw-blade wear is an important parameter governing the economy of the cutting process. Significant savings could be made when it is controlled effectively. In this study, a new methodology is employed for the determination of the saw-blade wear in the cutting of two types of marble. Wear of segments is determined by high-precision inductively coupled plasma method. Two types of marbles were used to investigate the wear performance of diamond-impregnated segments of circular saw-blade matrix. Taguchi mixed design L16 (4³ 2¹ ) is used as an experimental design and the results are evaluated statistically with Minitab. The results reveal that the specific wear rate (SWR) of Beige marble increases with the increase of the peripheral speed, traverse speed, depth of cut and down-cut mode operation. Additionally, it is demonstrated that the traverse speed and peripheral speed are the dominant cutting parameters affecting the SWR. It is also seen that similar trends are observed for Onyx marble (excluding peripheral speed). Finally, it is concluded that the proposed models can be effectively used for the estimation of the SWR.

4 illus, 8 tables, 38 ref

003363   ELSA M, KHORRAM A, OJO O O, PAIDAR M (Qazvin Science and Technology Park, Qazvin 34149-16818, Iran, Email: mortez.elsa@gmail.com) : Effect of bonding pressure on microstructure and mechanical properties of aluminium/copper diffusion-bonded joint. Sadhana 2019, 44(5), 126.

Pressure pulsation is notable for improving diffusion bonding process by breaking oxide layer present at the faying metal surfaces while an increased bonding pressure is envisaged to produce more compressive deformation (squeezing effect) on the reaction layer. This work aims at improving inter-atomic intersperse and mechanical properties of Al/Cu joint via the control of the bonding-compressive pressure. The bonding temperature (600 C) and time (60 min) were kept constant while the bonding pressure was varied between 5 and 12.5 MPa. The metallurgical and mechanical properties of the joint were studied. The results revealed that an oxide-free bond interface was produced in a pressure range of 5–12.5 MPa. The rise in the bonding pressure (5–12.5 MPa) increases the bond strength (78.39–108.47 MPa) and the diffusion depth (11.32–20.87 lm) between the Al/Cu interfaces. Five (5) distinctive regions having CuAl_2.4, Al_1.3Cu_3.1Sn, Al_2.5Cu_1.5Sn, CuAl_1.8 and AlCu_2.3Sn_1.4 phases were formed within the reaction layer due to the varying level of interspersing/inter-atomic diffusion. Maximum hardness increases with bonding pressure level towards the Cu side from 57 to 111 HV due to the precipitation of Al_2.5Cu_1.5Sn and AlCu_2.3Sn_1.4 phases.

9 illus, 3 tables, 26 ref

003412   SAHA P, SAMANTA P (National Institute of Technology Meghalaya, Shillong, Email: sahaprabir1@gmail.com) : Design and architecture of new 11:2 decimal compressors. Sadhana 2019, 44(5), 125.

Design and architectures of new 11:2 decimal compressors have been reported in this paper. Two design methodologies viz. delay and area optimized compressors have been introduced and implemented through tree structure of decimal number system. The architectures have been realized through vertical carry save addition algorithm, wherein to build up such addition of unconventional (4221 and 5211) binary coded decimal technique has been incorporated. Configurations of such compressors have been prototyped and transistor level implementation have been carried out to evaluate performance parameters like speed (propagation delay), power dissipation, area and area delay product. The architecture has been validated by Cadence virtuoso platform using 90 nm, 65 nm and 45 nm CMOS technology which provides useful statistics to determine the compressor’s performance parameters. The propagation delay of the delay optimized compressor equals to ~ 0.094 ns while the propagation delay of the area optimized compressor is ~ 0.124 ns using 90 nm CMOS technology at 1 V supply voltage. The reported architectures are ~ 24 % and ~ 41 % faster from its counterpart.

5 illus, 4 tables, 22 ref

003404   PRUSTY P, ROUT S, BARIK A K (Mechanical Engineering Dep, Engineering and Technology Coll, Bhubaneswar - 751 029, Email: ashokbarik.mech@gmail.com) : Heat transfer correlation for a triangular protruded surface with a cross-flow jet. Sadhana 2019, 44(5), 123.

In this paper, the fluid flow and heat transfer characteristics of a small rectangular channel fitted with triangular protrusions have been studied in a three-dimensional computational domain. A hybrid cooling strategy employing forced convection air stream with jet impingement on the protruded surface has been numerically studied by solving the conservation equations for mass, momentum, energy as well as turbulent kinetic energy and its dissipation rate in the frame work of finite volume method. The duct and nozzle Reynolds numbers and Prandtl number are varied in the range of 17,827 ≤ Re_Dh,duct ≤ 53,480, 5,135 ≤ Re_Dh,nz ≤ 12,044 and 0:7 ≤ Pr ≤12, respectively. The effects of the duct Reynolds number, nozzle Reynolds number and Prandtl number on heat transfer rate have been quantified. Extensive numerical computation has also been executed to collect the data for Nusselt number by varying each of the independent parameters. A non-linear regression analysis based on Lvenberg–Marquardt (L–M) method has been used to fit a correlation for Nusselt number utilizing the data captured from CFD analysis.

14 illus, 45 ref

003382   KABAKUS N, TORTUM A (Civil Engineering Dep, Ataturk Univ, 25240 Erzurum, Turkey, Email: nsirin@atauni.edu.tr) : Comparative analysis of trip generation models according to household characteristics for developed, developing and non-developed provinces in Turkey. Sadhana 2019, 44(5), 122.

Trip generation is the first step of transportation planning and trip distribution, stochastic separation, and assignment of traffic are done at the end of the finding of the values. In the scope of this study, the three provinces were selected from developed, developing, and non-developed provinces in Turkey and the field of the study was determined. In the determined provinces, trip generation models were generated according to the household characteristics by making household transportation surveys in the determined provinces. The aim of this study is to determine the trip generation of provinces of different categories according to the household characteristics related to the size and development situation of the provinces and to determine the factors affecting trip generation in these provinces. Besides, it is decided which one of the multiple linear, poisson, and negative binomial regression models is more appropriate for trip generation and Artificial Neural Networks model is compared with the most significant regression model. At the end of the analyses, Artificial Neural Network models have shown better performance among three different data sets. As a result, Artificial Neural Networks was proposed as an alternative method in the trip generation of the provinces.

7 illus, 8 tables, 27 ref

003378   JAVADI M A, HOSEINZADEH S, KHALAJI M, GHASEMIASL R (Islamic Azad Univ, Tehran, Iran, Email: Hoseinzadeh.siamak@gmail.com) : Optimization and analysis of exergy, economic, and environmental of a combined cycle power plant. Sadhana 2019, 44(5), 121.

In this study, a combined cycle power plant with a nominal capacity of 500 MW, including two gas turbine units and one steam turbine unit, is considered by a mathematical model. This study is carried out to optimize three objective functions of exergy efficiency, CO₂ emission and produced power costs. This multiobjective optimization has been carried out by using the Non-Dominated Sorting Genetic Algorithm (NSGA-II). The results indicate that the efficiency of the combined cycle power plant depends on the design parameters including gas turbine input temperature, compressor pressure ratio, and pinch point temperature. Furthermore, any change occurring in these settings may lead to noticeable changes in objective functions, so that the efficiency of this power plant is increased after optimization by up to 8.12 %, and its heat rate is correspondingly reduced from 7233 (kJ/kWh) to 7023 (kJ/kWh). Similarly, exergy destruction in the total system shows a reduction by 7.23 %.

8 illus, 6 tables, 50 ref

003410   RANJANI H G, PARAMASHIVAN D, SREENIVAS T V (Electrical Communication Engineering Dep, Indian Institute of Science, Bangalore, Email: ranjani@iisc.ac.in) : Discovering structural similarities among ragas in Indian Art Music: A computational approach. Sadhana 2019, 44(5), 120.

Indian Art Music has a huge variety of ragas. The similarity across ragas has traditionally been approached from various musicological viewpoints. This work aims at discovering structural similarities among renditions of ragas using a data-driven approach. Starting from melodic contours, we obtain the descriptive note-level transcription of each rendition. Repetitive note patterns of variable and fixed lengths are derived using stochastic models. We propose a latent variable approach for raga distinction based on statistics of these patterns. The posterior probability of the latent variable is shown to capture similarities across raga renditions. We show that it is possible to visualize the similarities in a low-dimensional embedded space. Experiments show that it is possible to compare and contrast relations and distances between ragas in the embedded space with the musicological knowledge of the same for both Hindustani and Carnatic music forms. The proposed approach also shows robustness to duration of rendition.

16 illus, 4 tables, 41 ref