000668   MA S, DUAN Z, SHAO Y, HUANG Z, LIU Y, TANG X (Civil Engineering and Architecture Dep, GuangXi Univ, Nanning- 530 004, China, Email: hzcslg@163.com) : Sheltering effect of vertical twin tunnel excavation for different horizontal distances on the ground and pipelines. Sadhana 2021, 46, 48.

Subway tunnels are often designed as twin or multiline overlapping tunnels. The sheltering effect from the upper tunnel on the excavation of the lower tunnel is obvious. However, the mechanism of this sheltering effect has not been examined via detailed systematic research. Therefore, in this paper, centrifugal model tests on the excavation of vertical twin tunnels under typical sheltering conditions were carried out. Then, relevant numerical simulations were conducted, focusing on the change law of the ground and pipeline settlements and the principal stress and shear strain of soil under different sheltering conditions. Combining the results of the centrifugal model tests and relevant numerical simulations, for twin tunnels in an overlapping arrangement, the maximum ground settlement is caused by the excavation in the sequence of the upper tunnel first. However, for twin tunnels in a shouldering arrangement, the opposite sequence is caused by the sheltering effect. Sheltering effect is most prominent when the twin tunnels are in an overlapping arrangement. When the horizontal distance between the twin tunnels is 1DT, the ground settlement caused by excavation in the different sequences is the same. It is a critical state in which the sheltering effect is balanced with a disturbance effect. When the horizontal distance is from 1DT to 1.8DT, the sheltering effect gradually decreases, and the disturbance effect dominates as the distance increases. When the horizontal distance is more than 1.8DT, the sheltering effect basically disappears, and only the disturbance effect exists. Finally, the sheltering coefficient C is proposed, which is related to the horizontal distance between the twin tunnels. By introducing the stochastic medium theory, an equation is proposed, which can quantitatively predict the ground settlement by excavation under sheltering effects at different horizontal distances.

20 illus, 3 tables, 23 ref

000666   KARTHEESWARAN A, JOTHI T J S, ARACKAL R S (Mechanical Engineering Dep, National Institute of Technology, Kerala- 673 601, Email: tjsjothi@nitc.ac.in) : Visualisation studies on plane jets at low reynolds numbers. Sadhana 2021, 46, 50.

Flow visualisation of plane jets in the Reynolds number (Re) range of 90 to 750 is carried out experimentally, considering water as fluid. A conventional rectangular nozzle with the exit dimensions of 20 mm 9 2 mm is used. Various visualisation experiments are carried out using a colour dye mixed or injected with the jet flow. Images are processed using image processing software to estimate the characteristics of the jets. Besides, to assess the growth of the shear layer in free jets, a nozzle with an extension of its base wall by 5 mm is considered. The resulting images indicate that the mean spread rate of a turbulent plane jet is around 0.152. In the case of laminar jets, a vortex street with large size vortices is observed at lower Reynolds numbers. The Strouhal number of the vortices formed in the laminar jet is observed to increase with an increase in the Reynolds number. The amplitude of the oscillations of a laminar jet column at Re & 90 is observed to increase with an increase in the axial distance. The dissipation and spread rates are lower for smaller Reynolds number laminar jet. The flow emerging from a nozzle with an extended base-wall is found to be asymmetric along its nozzle centreline, attributed to the delay in the shear layer formation at the wall side.

13 illus, 4 tables, 23 ref

000429   SINGH A P, CHATTERJEE K (Civil Engineering Dep, Indian Institute of Technology Roorkee, Roorkee- 247 667) : Effect of soil–wall friction angle on behaviour of sheet pile wall under surcharge loading. Proc Natl Acad Sci India Sect A Phys Sci 2021, 91(1), 169-79.

In this study, a solution is derived in the framework of the limit equilibrium approach for the design of cantilever sheet pile walls under both static and seismic conditions in cohesionless soil with uniform surcharge load located at the top of the wall. The proposed method satisfies the horizontal force equilibrium and moment equilibrium about toe simultaneously. From the results of the study, it is highlighted that the application of surcharge load increases the magnitude of bending moment along the depth of the sheet pile wall and deflection at the top of the wall. Further, the increase in plastic zone due to mobilisation of earth pressure is also observed. A parametric study is done by varying the soil–wall friction angle and magnitude of uniform surcharge load acting on the backfill of the cantilever sheet pile walls. From the results, it is observed that as the soil–wall friction angle increases, the maximum bending moment, deflection, depth of plastic zone and settlement adjacent to sheet pile wall decrease. Further, the increase in the magnitude of uniform surcharge increases the maximum bending moment, deflection, depth of plastic zone and settlement adjacent to sheet pile wall.

17 ref

000428   RANJAN N, SINGH R, AHUJA I P S (Production Engineering Dep, Guru Nanak Dev Engineering Coll, Ludhiana) : Mechanical, rheological and thermal investigations of biocompatible feedstock filament comprising of PVC, PP and HAp. Proc Natl Acad Sci India Sect A Phys Sci 2021, 91(1), 159-68.

In the present work, mechanical, rheological and thermal investigations for biocompatible feedstock filament wire (comprising of polyvinyl chloride and polypropylene and hydroxyapatite particles) have been conducted. The feedstock filament wire has been prepared (in-house) by twin-screw extrusion for commercial fused deposition modeling. This study also highlights the combined optimization of various mechanical properties (like peak load, break load, Young’s modulus and shore hardness) of the feedstock filament. The results have been supported by thermal analysis based upon differential scanning calorimetry, composite material morphology based upon scanning electron microscope analysis and rheological analysis based upon melt flow index.

27 ref

000425   JADAM T, RAHUL, DATTA S, MAHAPATRA S S (Mechanical Engineering Dep, National Institute of Technology, Rourkela- 769008, Odisha) : Electro-discharge machining (edm) of superalloy inconel 718 using triangular cross-sectioned copper tool electrode: emphasis on topography and metallurgical characteristics of the edmed work surface. Proc Natl Acad Sci India Sect A Phys Sci 2021, 91(1), 123-34.

A case experimental research towards investigating aspects of electro-discharge machining on Inconel 718 superalloy using copper tool electrode (triangular cross section) has been delineated herein. Based on three controllable process variables, viz. peak discharge current, pulse duration and gap voltage, experiments have been carried out to investigate their effects on surface crack density and white layer thickness observed onto the top surface of the EDMed end product. Additionally, EDS analysis has been carried out to investigate the extent of carbon enrichment incurred onto the machined surface caused by pyrolysis of the dielectric media. XRD tests have been carried out to compare metallurgical features (various phases/precipitates present, extent of grain refinement, crystallite size and dislocation density) of the EDMed work surface with respect to as-received Inconel 718. Results, thus obtained, have also been compared to those of micro-indentation hardness test data.

10 ref

000660   KIM C, LIU Z, LEE J (Mechanical Engineering Dep, Korea Univ of Technology and Education, Chungcheongnam-do 31253, Republic of Korea, Email: jlee@koreatech.ac.kr) : Effects of injection pressure and length-diameter ratio on the velocity and cavitation inside injector nozzle. Sadhana 2021, 46, 56.

Computational investigation was conducted to understand the effects of various parameters on nozzle flow and cavitation in a diesel fuel injector for a diesel engine. The effects of injector parameters were simulated for different conditions including the injection pressure, the outlet pressure, the position of the needle lift, and the length of the nozzle. Results show that some parameters have obvious influence on cavitation associated with nozzle flow. When the outlet pressure was constant, the velocity through the nozzle increased with the injection pressure, resulting in the cavitation at the injection pressure over 120 MPa. When the injection pressure was constant, the velocity inside nozzle decreased with the outlet pressure. As the needle tip moved closer to the bottom of minisac, the velocity inside nozzle decreased and the cavitation did not take place. The length of the nozzle hole had little effect on the velocity at inlet, but it affected the velocity distribution at outlet.

13 illus, 17 ref

000658   PRIYANKA R, SIVAPRAGASAM M (Aerospace Engineering Dep, M S Ramaiah Univ of Applied Sciences, Bangalore- 560 058, Email: sivapragasam.aae.et@msruas.ac.in) : Multi-fidelity surrogate model-based airfoil optimization at a transitional low Reynolds number. Sadhana 2021, 46, 58.

The aerodynamic design optimization of an airfoil is carried out at a transitional low Reynolds number in the framework of multi-fidelity surrogate modeling. Two multi-fidelity surrogate-based optimization methodologies are proposed. The first method involves the co-Kriging surrogate model with prediction-based high-fidelity model update strategy. The second method uses the Kriging model of the low-fidelity function, and subsequent co-Kriging modeling with high-fidelity infills done using the gradient-free trust-region approach. The high-fidelity solutions are obtained by solving the Reynolds-averaged Navier-Stokes equations with the flow transition modeled by the $\mathrm{\gamma }$-Re_$\theta$ model. The low-fidelity solutions are obtained by a panel code in conjunction with the eN method. The proposed optimization methodologies are applied to two different objective functions in the transitional low Reynolds number regime, namely, (i) maximization of lift coefficient, and (ii) maximization of endurance factor. Significant improvements in each of the objective functions are obtained using both these methodologies.

14 illus, 4 tables, 48 ref

000657   REDDY K N, KUMAR A, NAGENDRA R, VELAGA (Industrial and Systems Engineering Dep, Indian Institute of Technology, West Bengal- 721 302, Email: knreddy@iitkgp.ac.in) : Scenario-based two-stage stochastic programming for a hybrid manufacturing-remanufacturing system with the uncertainty of returns, quality and demand. Sadhana 2021, 46, 59.

This paper addresses the optimization of make-to-order hybrid manufacturing - remanufacturing system to make capacity and inventory decisions jointly along with production decisions. The proposed system considers a common production facility and the same assembly/disassembly line to perform manufacturing and remanufacturing operations simultaneously. The current study takes into account an environment where new and remanufactured (reman) products competing to each other that is, the common demand stream for both products but different selling prices. Furthermore, the relative capacity consumed by remanufacturing over the manufacturing is explained in two ways, namely less capacity intensive case and more capacity intensive case. Differently, from previous studies, we consider a scenario with a discounted selling price for reman products, shortage penalty costs, lost sales, disposal and uncertainty in demand, amount and yield of returns. Hence, to handle those uncertainties, a scenario-based stochastic programming model in a two-stage setting is presented. In the first stage, the raw material inventory and production capacity levels are planned and in the second stage, the production, inventory and disposal decisions are determined by balancing overage and underage costs. The results indicate that net values associated with new and reman products can be decisive in choosing either manufacturing or remanufacturing

4 illus, 5 tables, 24 ref

000656   SHANG H, ZHANG L, CHEN X, GUO P, ZHANG H (Chongqing Univ, Chongqing- 400 044, People’s Republic of China, Email: zhangli20@cqu.edu.cn) : Experimental investigation about effect of double-spark plug ignition on cyclic variation and knocking for SI engine. Sadhana 2021, 46, 60.

In order to analyze the effect of the double-spark plug ignition (DSI) on the heat release rate, cyclic variation in combustion and engine knocking, four different single- and double-spark plug ignition strategies are used for testing. Combustion diagnosis results show that when the DSI strategy is used, it can effectively promote the combustion process, increase the maximum combustion pressure, shorten the combustion duration and reduce the coefficient of cyclic variation (COV). Under low load condition, the effects are more pronounced. Test data reveals the following phenomenon. With the DSI strategy, both the cyclic variation in the early period of rapid-burning and in the later period of rapid-burning are reduced, especially in the early period of rapidburning. Then, the cyclic variation rate of the combustion duration is significantly reduced. Since the burning rate in the early period of rapid-burning is greatly accelerated, knocking tendency of the DSI engine is more obvious than that of the single-spark SI engine. The potential to improve engine performance and fuel economy by the DSI strategy largely depends on the optimization of the spark advance. Based on the optimization of the ignition timing of the DSI strategy S_28&28, the break mean effective pressure (BMEP) is improved by about 5%- 6% compared to the original 158FMI engine.

12 illus, 7 tables, 17 ref

000655   SAYYAD F, SENANAYAKE R (Mechanical Engineering Dep, Lincoln Univ, Petaling Jaya, Malaysia, Email: fbsayyad@gmail.com) : Experimental investigation on surface roughness of electroless Ni–B– TiO2 nanocomposite coatings. Sadhana 2021, 46, 61.

Magnesium and its alloys like AZ91 are used for various automotive, military and aviation applications. Nanocomposite coatings on AZ91 show significant improvement in the surface properties like wear resistance, hardness and corrosion properties. Electroless coatings have unique physicochemical and mechanical properties, for which they are being used increasingly. Most applications of the electroless coatings are based on their wear and corrosion resistance. However, the characteristic like luminescence has a great potential in defence and aerospace applications. In this research, surface roughness of AZ91 magnesium alloy due to nanocomposite coating processes of ENi–B–TiO₂ is experimentally investigated. It has been observed that as concentration of second-phase (TiO₂) particles increases, the surface roughness of coatings also increases.

4 illus, 2 tables, 15 ref

000654   CHATTERJEE D, GARAI S (CSIR-Central Mechanical Engineering Research Institute, Durgapur- 713 209, Email: d_chatterjee@cmeri.res.in) : Estimation of critical rotation rates for suppression of steady separation bubble behind a circular cylinder. Sadhana 2021, 46, 62.

An effort has been made in this paper to numerically estimate the critical rotational speeds for which the steady separation bubble completely disappears behind a circular cylinder. The cylinder is subjected to an unconfined free stream flow, however, fictitious confining boundaries are considered for computational convenience. The Reynolds numbers computed from the free stream flow velocity are considered in the range of 10–40. In this range of Reynolds number, the flow around a stationary circular cylinder remains steady and separated with the formation of a recirculation zone through counter-rotating vortices (separation bubble) behind the body. Rotational motion is provided to the cylinder that causes stabilization of the flow field. The separation bubble vanishes and an attached type flow feature is observed. The rotational speeds at which the recirculating zone behind the cylinder completely vanishes in the said range of Reynolds number are considered as the critical rotation rates. The aerodynamic coefficients are obtained for the specific operating conditions and a regime diagram is produced depicting the separated and the attached flows.

8 illus, 1 table, 17 ref

000653   DUBEY A K (ABES Engineering Coll, Ghaziabad- 201 009, Email: anildudenish@gmail.com) : Optimized hybrid learning for multi disease prediction enabled by lion with butterfly optimization algorithm. Sadhana 2021, 46, 63.

As there is a rapid growth in healthcare systems and biomedical data. Machine learning algorithms are utilized in many researches for predicting the risk of the diseases. The major intuition of the present paper is to plan for a novel methodology for multi-disease prediction using deep learning. The overall prediction methodology involves several steps such as ‘‘(a) Data Acquisition, (b) Optimal Feature selection, (c) Statistical feature Extraction, and (d) prediction’’. In the initial step, the medical datasets of diverse diseases is gathered from multiple benchmark sources. Further, the optimal feature selection is applied to the available set of attributes. This is accomplished by hybridizing two meta-heuristic algorithms such as Lion Algorithm (LA), and Butterfly Optimization Algorithm (BOA). In these prediction algorithms, the hidden neuron count of NN and DBN is finely tuned or optimized by the same hybrid Lion-based BOA (L-BOA). The experimental evaluation of various medical datasets validates that the prediction rate of the developed model outperforms several traditional methods.

10 illus, 16 tables, 50 ref

000652   RAI A, MITRA M (Aerospace Engineering Dep, Indian Institute of Technology, Kharagpur- 721 302, Email: mira@aero.iitkgp.ac.in) : A hybrid physics-assisted machine-learning-based damage detection using Lamb wave. Sadhana 2021, 46, 64.

This research presents a hybrid physics-aided multi-layer feed forward neural network (MLFFNN) model to improve damage detection under Lamb wave responses. Here, a damage parameter database (DPD) is created from the complex responses of a thin aluminum plate generated using finite-element (FE) simulations. A double pulse-echo transducer configuration is implemented over the 1.6 mm thick aluminum plate with notchlike defect, which generates only A₀ mode in the plate structure and records damage-specific S₀ mode. Sixty-six FE simulations are conducted, each representing a distinct damage scenario in terms of damage location and Lamb wave frequency. Artificial noise is added to compensate environmental interference. Orthogonal matching pursuit was performed to improve the sparsity of the signal. Thereafter, the damage-specific features are extracted from the sparsed S₀ signal to construct DPD for all 66 FE simulations. The fully developed DPD is deployed to train an MLFFNN supervised by a robust Levenberg–Marquardt algorithm. A set of initial tests are conducted for higher damage-depth to plate-thickness ratio with 1.0 mm notch depth, and the fully trained MLFFNN predicts the damage location with 99.94 % accuracy. The proposed algorithm achieves a good level of generalization, including the cases of overlapping echoes and cluttered responses due to multiple reflections for the given damage scenarios.

17 illus, 2 tables, 25 ref

000649   SOWMIYA M, THILAGAR S H (Electrical and Electronics Engineering Dep, Anna Univ, Chennai- 600 025, Email: sowmiyavision2020@gmail.com) : Design and performance analysis of a dual stator multiphase induction motor using finite element method. Sadhana 2021, 46, 67.

A new Dual Stator Multiphase Phase Induction Motor (DSMIM) configuration is proposed and described in this paper. Steady state equivalent circuit of DSMIM is developed and its performance parameters are calculated. The efficiency curves plotted under different excitation modes of the machine assists in operating it at a better efficiency for wider load range. Thus, the proposed configuration can be utilized in Electric Vehicles (EV) to efficiently support a sudden load change during acceleration, cruising and uphill driving patterns. A Finite Element Method (FEM) based design of the machine is done using MAGNET software. The electromagnetic performance of DSMIM is analyzed through the flux patterns obtained at different excitation modes. Its electromechanical performance is studied by analyzing the current, torque and speed developed under load driven conditions. The article also proposes an ideology behind the mechanical arrangement of DSMIM for fabrication. The simulation results are included to illustrate the performance of DSMIM. The results are compared and validated with the analytical results obtained through equivalent circuit approach.

18 illus, 5 tables, 40 ref

000647   KUMAR M, SATSANGI P S (Production and Industrial Engineering Dep, Punjab Engineering Coll, Chandigarh- 160 012, Email: mnjbrd.02@gmail.com) : A study on machining performance of wire electric discharge grinding (WEDG) process during machining of tungsten alloy micro-tools. Sadhana 2021, 46, 69.

In this experimental study, tungsten alloy micro-tools of high aspect ratio are machined through wire electric discharge grinding (WEDG) method using the step machining technique on a hybrid micro-electrodischarge machine to achieve high productivity and finish. Tungsten alloy micro-tools are widely used in the fabrication of miniature products. The precise and economical machining of the tungsten material with an optimum level of accuracy and surface properties is a challenge because of its exceptional characteristics like hot hardness, high strength, low wear, and corrosion rate. The material removal rate (MRR) and surface roughness (Ra) responses are studied during machining of micro-tools, selecting the variability of applied voltage, circuit capacitance, and spindle speed during machining for a constant-aspect-ratio micro-tool. Both voltage and capacitance are found to be influencing parameters for MRR and surface roughness. Higher voltage and capacitance values tend to increase MRR and roughness values on the machined micro-tool. Further, the parametric conditions are also identified for higher MRRs and lower surface roughness (Ra) values after employing the hybrid Taguchi design of experimentation methodology. Surface topography of the machined surface studied by energy-dispersive spectroscopy (EDS) reveals the presence of pyrolytic carbon and oxygen elements. Field emission scanning electron microscopy (FESEM) images show a little waviness across the machined surface. A mathematical model is developed to evaluate the correlation among governing parameters for machining response and validated by confirmation experiments. The machining procedure can be further developed to fabricate more predominant fluted micro-tools for difficult-to-machine tungsten material.

7 illus, 6 tables, 27 ref

000646   AROTE A, BADE M, BANERJEE J (Mechanical Engineering Dep, Sardar Vallabhbhai National Institute of Technology, Surat- 395 007, Email: jbaner@med.svnit.ac.in) : Properties of blended advection schemes for hyperbolic conservation laws. Sadhana 2021, 46, 70.

The fidelity of an advection-dominant numerical solution is significantly affected by the order of approximation applied for the given scalar. Numerical schemes that apply this approximation are generally prone to dissipative and dispersive errors while capturing sharp discontinuities in the scalar values. Hence, the present study introduces the Fromm-scheme-based blending formulation for two blended schemes that demonstrate the accuracy and monotonicity while capturing the discontinuity in the numerical solution. The present study demonstrates the spectral analysis for the stability and accuracy of these blended schemes. The proposed blended schemes are applied to the pure advection problems and are compared to their constituent higher-order schemes and other blended schemes. Furthermore, these schemes are also applied over the lid driven cavity and one-dimensional dam break problems to estimate their performance over an unknown velocity field.

15 illus, 4 tables, 24 ref

000645   DHARMIK B Y, LAUTRE N K (Mechanical Engineering Dep, Visvesvaraya National Institute of Technology, Nagpur- 440 010, Email: nfl_123@rediffmail.com) : Experimental evaluation on weld zone of thin–laminated stacked sheets post-GTA weld of CRNO electrical steel. Sadhana 2021, 46, 71.

Electric motor industries widely use cold-rolled non-oriented (CRNO) electrical steel sheets (ESSs) as the magnetic core. The sheets are of low carbon–silicon, thin (0.5 mm), and laminated and joined as a stack with gas tungsten arc (GTA) welding. A weld zone is affected by the welding heat and dependent on welding current (30–110 A). The fusion zone (FZ) and heat-affected zone (HAZ) of the weld zone are analyzed for variation in the base metal (BM) and microstructural properties using a scanning electron microscope (SEM) and optical microscope (OM). The effects of weld depth, weld width, stress–strain relationship, filler material, and grain size are investigated with a weld current change. Tensile and micro-hardness testing in FZ and HAZ revealed a change of failure in zones, maximum fracture load, and micro-hardness. The effect of grain size and completely ferritic phases (a-phase and c-phase) in the weld zone is also studied. All the properties variations are compared and correlated to the input welding heat on the thin–laminated, non-grain-oriented stack on ESS.

15 illus, 6 tables, 32 ref

000644   PODDER D, CHAKRABORTY S, MANDAL U K (Production Engineering Dep, National Institute of Technology, Agartala- 799 046, Email: debashis5645@gmail.com) : RSM analysis of impact property and characterization of Al6063-CuTiO₂-ZrO₂ composites fabricated by stir casting process. Sadhana 2021, 46, 72.

Aluminum Metal Matrix Composites (AMMCs) are nowadays well-acknowledged engineering materials which have been widely used in the field of automotive and aerospace industries mainly due to its unique properties. Thus, aluminium 6063 alloy has been chosen as base matrix along with copper to prepare the composite where copper has been added as it enhances the thermal and electrical properties. In this present study, stir casting technique has been used to fabricate an aluminium-copper composite by adding titanium dioxide and zirconium dioxide as reinforcements. The effect of different process parameters like percentage of reinforcement, different particle sizes of Zirconium Dioxide (ZrO2) and Titanium Dioxide (TiO2) mixed particulates, percentage of copper, percentage of brick powder, cooling time, percentage of binder and stirring time on impact property have also been studied. Experimental results have been analyzed by signal to noise ratio (SN ratio) plot and analysis of variance (ANOVA) and a response surface model (RSM) has also been used to predict the impact property and to estimate the influencing factors too. Further, the response surface model has been validated by conducting the experiments on the fabricated composites for impact property. The result shows very less variation with the experimental result. The micro-structural properties have also been analyzed by optical microscope, X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Scanning Electron Microscopy (SEM) and X-ray elemental mapping techniques. The results show an analogous distribution of particles along with the better impact and micro-structural properties.

9 illus, 8 tables, 41 ref

000643   VIGNESH M, RAMANUJAM R (Vellore Institute of Technology, Vellore- 632 014, Email: mvignesh4592@yahoo.in) : Statistical modelling and analysis of material removal rate and surface roughness during wire electrical discharge hybrid turning (WEDHT) process. Sadhana 2021, 46, 73.

The non-traditional machining process is highly recommended for machining difficult-to-cut materials with increased hardness, toughness, work hardening effect, and poor thermal diffusivity, etc. Wire electrical discharge machining (Wire-EDM) is one of the above said processes used to machine material which are electrically conductive. One of the variants of Wire-EDM process is wire electrical discharge hybrid turning (WEDHT) process, in which, the work material is made to rotate during material removal resulting in cylindrical components manufacturing. This process follows the principle of sparking and erosion for material removal with moving wire as a tool electrode. In the present study, WEDHT process is performed on Ti-6Al-4V alloy, which has applications in the areas of biomedical, marine, chemical, aerospace, etc. 27 experiments are performed using diffusion annealed zinc coated brass wire as the tool electrode by varying servo feed, pulse ON time and wire feed rate at three different levels to study the surface quality and material removal as the output performances. Atomic force microscopy (AFM) technique gives a 3D profile of the machined surface and measures the surface roughness. These measured 3D results are validated once again in 2D surface profile meter. The factor effects of all three input parameters are analyzed individually and analysis of variance (ANOVA) for all the performance responses are studied to know the most contributing factor in deciding the surface roughness (SR) and material removal, respectively. The regression analysis is performed for the response measures and the model parameters are analysed for goodness of fit using residual plot. Pulse ON time contributes more in deciding the SR and material removal rate (MRR) of the component followed by servo feed and wire feed rate. The interaction effects of the parameters are found to be insignificant.

4 illus, 7 tables, 20 ref

000642   BALLAV S, SARKAR G A, PARUI S K (Electronics and Telecommunication Engineering Dep, Indian Institute of Engineering Science and Technology, Howrah- 711 103, Email: ballav.suparna@gmail.com) : High-selective filtering dielectric resonator antenna by integrating band-rejection resonators in feedline. Sadhana 2021, 46, 74.

This paper demonstrates a completely new technique to obtain high-selective filtering response of a rectangular dielectric resonator antenna (DRA). The proposed filtering antenna mainly composed of a rectangular DRA driven by a stair shaped slot on the ground plane and a feed line with multiple bandstop characteristics. Two pairs of band-rejection resonators with dissimilar resonant frequencies is integrated in the 50 Ohm microstrip line to generate four transmission zeros on either side of passband which offers the filtering response for the rectangular DRA. Just by inserting two identical pair of band-rejection resonators in feed below the ground plane, the proposed DRA exhibits a consistent broadside gain response in passband with skirt selectivity at both upper and lower band-edge with four radiation nulls. Three distinct resonance frequencies of TE111 mode are excited in close proximity within the DRA due to the different loading effect of band-rejection resonators in the feed, enhancing the operating bandwidth of antenna to 11.8 %.

11 illus, 1 table, 27 ref

000641   KAR A, SENGUPTA M (Electrical Engineering Dep, Indian Institute of Engineering Science and Technology, Howrah, West Bengal, Email: abhishekkar1986@gmail.com) : Design, analysis and experimental validation of a variable frequency. Sadhana 2021, 46, 75.

This paper proposes a novel, reliable, efficient and cost-effective implementation of partial soft switching in a silicon carbide (SiC)-based variable-frequency phase-modulated resonant transition converter (PMRTC) used in manual metal arc welding (MMAW) applications at a peak power of 1.3 kW. The switching frequency (f_sw) of the converter is increased from 100 kHz at no load to around 150 kHz for a rated power of 1.0 kW. Such an approach is not found in the existing literature. At such frequencies, a significant proportion of the output filter inductance is contributed by the inherent self-inductance of the output ‘‘lead cables’’. The switching losses in the semiconductor devices are reduced at no-load condition by reduction of the operating frequency. Load regulation is achieved at 150 kHz by implementing phase-shifted PWM technique. Implementation of partial soft switching without using additional components is another significant contribution of this work. The reduced size and weight of the filter inductor in turn reduces the overall size, weight and cost of the system but puts a restriction on the output lead cable length, which is another salient finding of this work. Since at high frequency the transformer model changes, design and finite-element method (FEM)-based simulation of the transformer are also presented in this paper. Loss calculations at 100 and 150 kHz are discussed. The entire converter is fabricated in the laboratory. Experimental and simulated results are found to be in excellent agreement.

25 illus, 3 tables, 46 ref

000640   KHARE S, SAHA U K (Mechanical Engineering Dep, Indian Institute of Technology, Guwahati- 781 039, Email: shivang.khare@ntnu.no) : Rocket nozzles: 75 years of research and development. Sadhana 2021, 46, 76.

The nozzle forms a large segment of the rocket engine structure, and as a whole, the performance of a rocket largely depends upon its aerodynamic design. The principal parameters in this context are the shape of the nozzle contour and the nozzle area expansion ratio. A careful shaping of the nozzle contour can lead to a high gain in its performance. As a consequence of intensive research, the design and the shape of rocket nozzles have undergone a series of development over the last several decades. The notable among them are conical, bell, plug, expansion-deflection and dual bell nozzles, besides the recently developed multi nozzle grid. However, to the best of authors’ knowledge, no article has reviewed the entire group of nozzles in a systematic and comprehensive manner. This paper aims to review and bring all such development in one single frame. The article mainly focuses on the aerodynamic aspects of all the rocket nozzles developed till date and summarizes the major findings covering their design, development, utilization, benefits and limitations. At the end, the future possibilities of development are also recommended.

25 illus, 9 tables, 131 ref

000581   LONG P T, DAT D V, TAN L V (Industrial Univ, Ho Chi Minh City- 70000, Vietnam, Email: levantan@iuh.edu.vn ) : Modeling synthesis amorphous magnesium silicate for adsorption of lead, cadmium and arsenic on well-developed surface area in aqueous solution. Rasayan J Chem 2021, 14(1), 608-15.

In this work, a well-developed surface area amorphous magnesium silicate was synthesized and seriously optimized the preparation process by Box-Wilson Design Model. Therein, the amorphous nature of magnesium silicate after being synthesized was confirmed by the X-ray diffraction method, the presence of functional groups was determined by Fourier-transform infrared spectroscopy and the surface area was analyzed by Brunauer–Emmett–Teller method. The synthesized material was then applied to simultaneously adsorb Pb, Cd and As from three water types: the simulated polluted water, the real wastewater and real polluted well water. According to the obtained results, magnesium silicate was synthesized at optimum conditions that have a special surface area of 454 m² /g, a pore volume of 0.325 mL/g and an average particle size of 116 μm. The synthesized magnesium silicate is excellently capable of simultaneous Pb, Cd, As adsorption in three types of water samples. The total content of these heavy metals was adsorbed in a simulated polluted water sample, wastewater sample and well water sample is 4.76 mg/g, 3.34 mg/g and 3.72 mg/g in sequence. Besides, the synthesized magnesium silicate can also adsorb other heavy metal ions such as Cr, Cu, Fe, Zn, Mn.

5 illus, 7 tables, 15 ref

000564   KARAMAN N, MANGESTIYONO W, MURYANTO S, JAMARI J, BAYUSENO A P (Mechanical Engineering Dep, Diponegoro Univ, Semarang, Indonesia, Email: apbayuseno@gmail.com ) : Morphology of barite precipitated from induced flow vibration and the presence of chemical additives. Rasayan J Chem 2021, 14(1), 466-72.

Crystallization of barite (BaSO₄) in industrial processes has been intensively investigated for the production of fine particles. In this way, crystallite size and morphology are important characteristics determining the quality product of barite. The effects of the mechanical vibration and the presence of chemical additives in the solution chemistry on the properties of barite particles were examined in this study. Barite crystal was formed through the experiments of the vibrated pipes of water flowing and adding chemical additives (formic, tartaric, oxalic, and acetic acids). The crystal morphology of barite in the different crystallographic directions corresponding to the X-ray diffraction (XRD) patterns was examined. Here, barite morphology with rosettes was predominantly observed by SEM. The study demonstrated that barite with nano-crystalline was successfully precipitated from the chemistry solution. Barite particles gradually decreased in size when crystallographic planes increased with 2$\theta$-values. No significant variation of barite crystal morphologies was found, but rosette- fine crystals might transform into granular nanocrystals when induced by vibration. Importantly, the mechanical vibration and chemical additives with acids in the solution chemistry influenced the morphology of barite. In practical terms, the induced mechanical vibration and the added acids could be an important unit operation for the production of barite with controlled morphology.

2 illus, 1 table, 44 ref

000535   FIRDAUS F E, DACHYAR M (Chemical Engineering Dep, Jayabaya Univ, Jakarta- 13210, Indonesia, Email: flora_elvistia@yahoo.com ) : Polyvinyl chloride into epoxy matrix in the production of bamboo composite. Rasayan J Chem 2021, 14(1), 233-40.

The serious discussion about the continuity of natural resources has led to regenerate interest regarding biomaterial with the focus on renewable raw materials as the replacement of synthetic materials. Natural fiber composite (NFC) is gaining the attention of researchers and academicians due to its role to resolve the current ecological and environmental problems. Bamboo fiber has demonstrated its hydrophilicity which was similar to distinct natural fibers, it absorbs a meaningful amount of moisture. Adding filler polyvinyl chloride (PVC) to epoxy matrix covered the weaknesses adhesion of bamboo-matrix, showed the suitability of thermoplastics to a thermosetting matrix to the ultimate mechanical property of bamboo composite.

6 illus, 3 tables, 34 ref

000528   SUMATHI R, SRIRAM G (Civil & Structural Engineering Dep, Sri Chandrasekharendra Saraswathi ViswaMahaVidyalaya, Kanchipuram - 631 561, Email: sumathiram72@gmail.com) : Tree leaves as bio indicators for monitoring atmospheric heavy metals in Kanchipuram town. Rasayan J Chem 2021, 14(1), 179-85.

Environmental pollution from heavy metals has tremendously increased across the world. The sudden expansion of industrial activities and rapid growth in population lead to the increased concentration of pollutants in the Kanchipuram town, hence it is very essential to monitor their concentration in the ambient air. Tree leaves have been used as a feasible tool to measure and observe the heavy metals level in this region. In this research, selected tree leaves were sampled from the different locations of the town and heavy metal such as Iron, Lead, Copper, Zinc, Aluminum, Cadmium, Arsenic, Chromium and Manganese deposited on them were analyzed by Inductively coupled plasma mass spectrometry. Among nine metals selected for the analysis Iron and Aluminum were in higher concentration in all the selected sites from all the samples and Copper, Zinc, Manganese were in lowest concentration in some of the samples collected from a few sites. Lead, Cadmium, Chromium and Arsenic were not identified in any samples collected at all sites. This experimental analysis clearly indicated that the absorption capacity of heavy metals differs from species to species and with sampling locations. The emission of heavy metals was from various man made activities and it should be controlled by stringent rules and regulatory measures. Hence this study proved the tree species chosen should acted as an effective tool for Iron, Aluminum and Manganese in the ambiance environment.

7 illus, 3 tables, 24 ref

000518   ELEWA R E, FAYOMI O S I, AFOLALU S A, ADEMUYIWA F T (Mechanical Engineering Dep, Covenant Univ, Ota, Nigeria, Email: ojo.fayomi@covenantuniversity.edu.ng) : Material selection and corrosion assessment of galvanized roofing sheet: Potentiodynamic investigation, mathematical modeling and simulation. Rasayan J Chem 2021, 14(1), 111-24.

Galvanised roofing sheet is widely used in the construction and building industry. However, the challenge caused by corrosion under service failure has led to this present work. This study presents the experimental investigation and simulated prediction of the selective material in 3.5 % NaCl condition. The corrosion resistance properties were examined using the potentiodynamic polarization technique and COMSOL. The mathematical modeling and simulation analyzed when done with model geometry in a single electrolyte domain and predicted for 1, 6 and 12 months for a sample labeled A-E. The results show that sample C provide lower corrosion deformation among all sample under investigation with Rp of 234.24 Ω, and CR of 0.51052 mm/y and corr value of -1.2837 (V) compare to sample A with higher corrosion rate of 2.9085 mm/yr and corr of -1.489 (V).

22 illus, 1 table, 24 ref

000509   KAMALANANDHINI M, ANNADURAI R, DHEEPAK S, DEEPAK P, METILDA J E (Civil Engineering Dep, SRM Institute of Science and Technology, Kattankulathur- 603 203, Email: nandhinimohan90@gmail.com) : Assessment of hydrological drought condition and its impact on water quality-a case study in parts of Chengalpattu District, Tamil Nadu, India. Rasayan J Chem 2021, 14(1), 51-7.

Irregular rainfall leads to over-exploitation of groundwater. The shortage of groundwater is a significant concern, and it contributes to the occurrence of hydrological drought. The study is proposed to measure the severity of the hydrological drought. Chengalpattu district located in Tamilnadu, India was identified as the study area because this district received irregular rainfall in the recent past. The hydrological drought assessment was performed with 30 years of rainfall data and the water quality data for the study area. Standardized Precipitation Index and Interpolation techniques were considered as measures of hydrological drought. Rainfall forecasting was done to identify the trend of rainfall over the next 30 years after studying the historical trend. Furthermore, the Water Quality Index was computed in multiple locations to categorize the water quality. Interpolation technique was used for ranging the water quality into nine classes. The result from the standardized precipitation index indicates, the study area is subjected to the occurrence of hydrological drought. The result from the water quality index indicates, there is no impact on the water quality due to the occurrence of a drought event.

13 illus, 1 table, 15 ref

000185   AL-GH S A (Electrical Engineering Dep, Albaha Univ, Albaha, Kingdom of Saudi Arabia, Email: sasg2000@gmail.com) : Effect of leaves and acids types on the electrical absorbance of dye sensitized solar cell (DSSC) using nanostructured zinc oxide. Orient J Chem 2021, 37(1), 181-6.

Solar energy is the most promising sources of energy in KSA due to the constant high solar radiation throughout the year. This was not used effectively due to the solar cells rising costs. Nano solar cells are the promising alternative in comparison to silicon solar cells due to its lower cost. Leaves of green cabbage and orange plant used as sensitizers. The effect of extracted temperatures, and immersed periods on the energy conversion efficiency was studied. Among the previous dyes, orange showed the best efficiency. The Nano dye sensitized solar cells (NDSSC’s) performance improved through controlling the extraction solution temperature and both the pre-treatments of the nano zinc oxide glass substrate and its post-treatments films using hydrochloric, phosphoric and nitric acids. The max conversion efficiency is 0.141 at 60o C and 0.11 at 45o C for both orange and green cabbage respectively. The pre-treatment of the FTO with HCL, HNO3 and H3 PO4 showed an efficiency improvement of 214 %, 180 % and 140 % at 8 h using orange leaves dye, and 207 %, 184 % and 152 % respectively at 6 hrs using green cabbage.

12 illus, 23 ref

000162   AGRAWAL A K, GUPTA A A, VORA M K (Mechanical Engineering Dep, Indian Institute of Technology (BHU), Varanasi- 221 005) : Optimal pricing and lot-sizing policies under promotional expense for some Veblen products. Opsearch 2021, 58(1), 83-108.

The desire for social status motivates people to possess rare and exclusive luxury products. People like to consume expensive product and service in order to associate themselves with the elite class and build a distinct image of self in society. The demand of luxury products increases with the increase in the price. This phenomenon is also known as Veblen effect, and products with such characteristics are called Veblen products. The demand for products, in general, is positively influenced by promotional expenses. Research suggests that the promotional effort may provide an opportunity to charge more of selling price without sacrificing the demand. With this aspect, the paper focuses on determining the optimal sales price, lot-size as well as promotional expenses for Veblen products. The promotional expense for the two different markets; niche as well as the mass market has been considered. A mathematical model has been proposed for obtaining the optimal price, lot-size and promotional expenses for such product. Some illustrative numerical examples have been taken for both the markets and solved with the help of LINGO optimization software. The sensitivity analysis was also carried out and observed that ordering cost and holding cost rate has almost no impact on optimal inventory policy, but the unit cost has. The proposed formulation of the considered problem is a non-linear integer programming mathematical model and is thus NP-hard. Therefore, genetic algorithm and teaching–learning-based optimization (TLBO) based heuristics have been proposed for solving the problem in a computationally efficient manner. However, these methods were found to take more CPU time compared to LINGO optimization software. TLBO takes the highest CPU time but is rendering solutions like the ones from LINGO.

55 ref

000160   JAIN P K, QUAMER W, PAMULA R (Computer Science and Engineering Dep, Indian Institute of Technology, Dhanbad- 826 004, Jharkhand) : Sports result prediction using data mining techniques in comparison with base line model. Opsearch 2021, 58(1), 54-70.

Sports prediction is one of the recent growing areas of interest entailing good prediction accuracy. Coaches require models in order to assess their players, analyse opponent teams and formulate winning strategies. Generation of comprehensive statistical data in sports has enabled data mining (DM) techniques to be applied to it in order to extract underlying predictive information. In this paper, an approach based on data mining is proposed for result prediction in sports. The work includes pre-processing of data, feature extraction, attribute selection and application of DM algorithms as a learning strategy. To validate our proposed model, a case study concerning prediction of the results of Indian Premier League (IPL) matches is illustrated. The constructed models are based on the performance of teams in past matches, player performance indices, opposition team information and external factors, and therefore, relevant features are engineered to indicate the same. The best prediction accuracy was found to be 70.58 %.

22 ref

000159   KUMAR K, SINGH S, BANWAIT S S (Mechanical Engineering Dep, National Institute of Technical Teachers Training and Research, Chandigarh- 160 019) : Optimum design and selection of wire rope for hot rolling shop applications. Opsearch 2021, 58(1), 29-53.

Optimal selection of wire rope for various industrial applications is a multidisciplinary procedure. In this paper, optimum selection of wire rope for winch trolley in hot rolling shop is comprehensively demonstrated using finite element analysis. Powerfoam wire rope can be operated at lower D/d ratio and have 2.5 times longer service life as compared to their stranded conventional counterpart. The parameter-based geometric models of commercially available multi-layer wire ropes of 1 + 6 + 6 strand construction are designed using modelling software, SolidWorks, and procedure is followed by finite element analysis on ANSYS. The service life of wire rope is a function of factor of safety. Finally, cost analysis is delivered for optimum selection of wire rope, as an economical insight of the study.

47 ref

000147   CHOUDHARY M P, CHARAN H D, ACHARYA B (Civil Engineering Dep, Rajasthan Technical Univ, Kota- 324 010, Email: choudhary_mp@yahoo.co.in) : A novel approach for disposing agriculture waste, minimizing air pollution and amending soil through biochar production and application. Nat Environ Pollut Technol 2021, 20(1), 243-9.

The burning of crop residues (traditionally called ‘Parali’) has recently become a hot topic in India because it is presumed to be one of the reasons for abnormally high levels of air pollution in New Delhi, the capital city of India, after harvesting of Kharif crops during winter months. During the process of finding out a feasible solution for quick disposal of agricultural waste in a safer way, a novel method has been developed by the authors in which crop residue is converted into a useful product, biochar, which can be applied back to the fields for amendment of soil. It not only reduces the introduction of harmful gases into the environment but also improves the physical and chemical properties of the soil. This method is very simple and can be adopted by an individual farmer without much investment and technical skills. Many studies have been conducted on the factors involved in the production and use of biochar as a soil amendment; but in India, not much work has been carried out yet, as it is relatively a new concept in terms of using biomass for biochar production and application. Although biochar is not a new product, it has drawn the attention of researchers and other stakeholders in the near past because of its usefulness in improving the physical and chemical properties of the soil and at the same time reducing greenhouse gas emission, which is one of the biggest challenges for the modern world to protect the environment.

14 illus, 2 tables, 23 ref

000139   ZHOU W (Engineering Management Dep, Wenhua Coll, Wuhan- 430 074, China, Email: whut_zwf@126.com) : Carbon emission estimation of prefabricated buildings based on life cycle assessment model. Nat Environ Pollut Technol 2021, 20(1), 147-52.

As a typical secondary industry in China, the building industry promotes China’s construction and development significantly. The urban construction scale is expanding continuously with the increase of the urbanization rate. However, resources needed for construction and influences of construction on the ecological environment are enormous, which further cause resource consumption and environmental destructions. Therefore, changing the traditional mode of construction and promoting the development of prefabricated buildings vigorously are conducive to realize the goal of environmental protection and resource conservation. In this study, a life cycle assessment model for prefabricated buildings was constructed based on the basic data of resource and energy consumption in the production stage, transportation stage, and field installation stage. The total carbon emission of a prefabricated building in Wuhan City was estimated, and specific energy conservation and emission reduction measures were proposed. Results show that prefabricated buildings have become a major manifestation of the industrialization of construction, represented by America, Germany, and Japan. In the case study, the total carbon emission of prefabricated components in the project is 3277.66 t, in which the carbon emissions in the production stage, transportation stage, and field installation stage account for 86.58%, 12.37%, and 1.05%, respectively. Based on the above research results, the further decrease in carbon emissions of prefabricated buildings by promoting the development of building energy efficiency and prefabricated buildings, accelerating R&D and innovation of prefabricated building technologies, and strengthening training to designers related with installation of prefabricated buildings is suggested. Research conclusions have important significance in various aspects, such as providing case-based references and guidance to the carbon emission reduction of prefabricated buildings and supply basic data to decrease carbon emission caused by the production of building materials, developing new environmentally friendly materials to relieve the impact of carbon emissions from the building industry on the environment, realizing energy conservation and emission in the field of construction, and promoting the sustainable development of prefabricated buildings.

1 illus, 2 tables, 13 ref

000138   RANJAN M, SINGH P K, SRIVASTAV A L ( Civil Engineering Dep, Indian Institute of Technology, Varanasi, Email: manish040533@gmail.com) : Application of hydrous bismuth oxide for arsenic removal from aqueous solutions. Nat Environ Pollut Technol 2021, 20(1), 133-45.

The present study is devoted to arsenic sorption on hydrous bismuth oxide (HBO) through batch and column studies. Advantage of the adsorbent includes arsenic removal in addition to the simultaneous removal of nitrate and fluoride from aqueous solution. Both the forms of arsenic tested by adsorbent in which affinity for arsenic (V) was found better than arsenic (III). Langmuir isotherm and pseudo-secondorder kinetic models were found a fit with the experimental data. Calculation of adsorption energy and increased level of chloride in treated water indicated the possible role of physical adsorption and ion exchange phenomenon in arsenic(V) sorption. A fixed bed column study gave 615 mL of treated water [As (V) < 0.01mg/L] from 0.085 mg/L arsenic (V) spiked influent with a sorption potential of 13.1-19.6 μg/g. XRD and EDS analyses confirmed the adsorption of arsenic (V) and the presence of chloride in the exhausted bed of adsorbent. The thermodynamic parameter has shown the endothermic and spontaneous process of adsorption.

9 illus, 4 tables, 83 ref

000029   PRASAD V, DAS D (ECE Dep, Assam Univ, Silchar) : Design of voltage level shifter using CNTFETs. Natl Acad Sci Lett 2021, 44(2), 139-42.

Level shifters (LSs) are used to interface with different voltage domains. In this work, a voltage LS is presented for different ranges of input–output voltage conversion. This design presents a high-speed, energy-efficient and robust dual-supply level converter based on multi-threshold carbon nanotube FETs (CNTFETs). The chirality of CNTs is suitably chosen to adjust the threshold voltage of CNTFETs. The proposed circuit is capable of shifting the input voltage level from the deep sub-threshold (0.25 V) to the above-threshold domain (0.45 V) and above-threshold (0.45 V) to nominal voltage domain (0.9 V). The results of the simulation are obtained based on the MOSFET-like CNTFET model at 32 nm technology node. The proposed circuit exhibits an average propagation delay of ∼∼63 ps and ∼∼32 ps, for two different voltage levels, respectively, and dissipates lesser static power than the existing circuits based on CNTFET.

10 ref

000028   JUN Z, CONGXIAO B, XING L (Electronic Engineering Dep, Tsinghua Univ, Beijing- 100 084, China) : Which switch to collect statistics in software-defined networks. Natl Acad Sci Lett 2020, 44(2), 133-7.

Many monitoring methods have been proposed, due to that network measurement is essential in Software-Defined Networking. However, periodically or adaptively collecting statistics from software switches using per-flow queries incurs significant communication cost and thus increases the loads of switches. In this letter, we propose OpenCost, an approach to decide which switch to collect statistics in Software-Defined Networks based on nonlinear integer programming (NLIP). Simulation results show that OpenCost can reduce the communication cost by 55% in average. OpenCost is an approach based on nonlinear integer programming algorithm, which can be used to reduce communication cost induced by network measurement in Software-Defined Networking. Experiments show that OpenCost can be beneficial to save operating cost for Internet service provider.

11 ref

000027   AGGARWAL S (Electronics and Communication Engineering Dep, MANIT, Bhopal) : Application of gaussian q-function approximations in fluctuating beckmann fading model. Natl Acad Sci Lett 2020, 44(2), 125-31.

This letter is an application of various exponential-based approximations to Gaussian Q-function, which are used to derive a generalized closed-form solution for the symbol error probability (SEP) over recently introduced Fluctuating Beckmann fading model. This model covers all the other important fadings like Gaussian, Rayleigh, Rician, Nakagami-m, η−μη−μ, κ−μκ−μ, shadowed Rician and κ−μκ−μ distributions as special cases. The SEP expression is mathematically effortless and requires elementary power function computations only.

17 ref

000009   SINGH P, KIM B W, JUNG S-Y (Electronic Engineering Dep, Yeungnam Univ, Gyeongbuk- 38541, Republic of Korea) : DS-OOK for terahertz band nanonetworks. Natl Acad Sci Lett 2021, 44(1), 43-6.

This study proposes a method for modulation and multiple access based on Direct Sequence On–Off Keying (DS-OOK) for the pulse-based communication in the Terahertz (THz) band. Using the unique properties of OOK as a modulation scheme, direct sequence could be employed as a mechanism to distinguish between distinct users transmitting simultaneously. Moreover, this scheme does not require coordination between transmitter and receiver and can be implemented in both ad hoc and infrastructure-based networks. The performance of the scheme is analyzed in terms of bit error rate for different spreading codes. Simulation results show that the choice of a proper spreading code plays a critical role in employing DS-OOK for THz band communication and could enhance the multiple-access performance even with a large number of interfering users.

6 ref

044204   MOIRANGTHEM L, PRAVEEN N (Life Science Dep, CHRIST (Deemed to be Univ, Bangalore - 560 029, Karnataka, Email: lutrilee@gmail.com) : Phytochemical analysis and antioxidant activity studies of leaf of Brassica juncea var. Rugosa through sequential solvent extraction. Int J Pharm Sci & Res 2020, 11(1), 343-51.

To find out different qualitative and quantitative phytochemical properties, it’s in-vitro antioxidant properties and peroxidase activity of Brassica juncea var. Rugosa (record tro- 50197928) with fresh and sequential solvent extracts. Methods: The leaf sample of Brassica juncea var. rugosa was collected from Manipur and the sample was dried. The dried powder was extracted using Soxhlet with the sequential solvent of non-polar to polar. Preliminary phytochemical analysis for proteins, carbohydrates, phenols, alkaloids, flavonoids, tannins, saponins, steroids, terpenoids, and quantitative estimation for total proteins, carbohydrates, alkaloids, phenols, flavonoids, and tannins. In-vitro, antioxidant activity was analyzed by using DPPH assay. Peroxidase activity was also checked. Results: The plant extracts showed the presence of a considerable amount of total alkaloids, total phenols, total flavonoids, total tannins, total proteins, total carbohydrates. The plant extracts also showed high antioxidant and peroxidase activity. Conclusions: From the study, we can conclude that the plant Brassica juncea var. rugosa has many important secondary metabolites and it has a potential for strong antioxidants.

2 illus, 9 tables, 36 ref

044203   MANAN A R , KANAN G G, NIRAJ Y V, NISHIT D P (Ramanbhai Patel Coll of Pharmacy, Anan - 388 421, Gujarat, Email: mananraval.ph@charusat.ac.in) : Estimation of withaferin – a from Ashwagandhadi lehya using hplc. Int J Pharm Sci & Res 2020, 11(1), 334-42.

Ashwagandhadi lehya is an Ayurveda formulation, official in Ayurvedic Formulary of India and used as aphrodisiac, tonic, rejuvenating agents etc. It is one of the major components of Ashwagandhadi lehya is Withania somnifera which contain Withaferin –A. The study was undertaken to develop an analytical method using HPLC to estimate Withaferin - A, being a marker from, methanolic extract of Ashwagandhadi lehya as one of the quality parameters. Method development involved simple sample preparation without any purification, as well as isocratic separation of Withaferin-A. The method was subjected to validation involving establishing linearity, precision, accuracy, specificity, and robustness.Optimized mobile phase was acetonitrile: water (45: 55 v/v) contained 1 % v/v glacial acetic acid. The column used was Phenomenex (250 × 4.6 mm, 5 µm) with flow rate set at 1 ml/min and chromatogram was recorded at 216 nm. The studies showed that peak corresponding to Withaferin – A within concentration range of 1-75 µg/ml was found to be correlated with respective concentration with correlation coefficient (r2 ) 0.99802 ± 0.0004. The developed analytical method was found precise, while accuracy was established using standard addition method. The average recovery was 95.59 %, when determined at three different spiking levels (50 %, 100 % & 150 %), in the preanalyzed sample solution. LOD was found to be 0.3 µg/ml and LOQ was 0.1 µg/ml. Robustness study suggested that increase in acetonitrile proportion, increased RT as well as increase in flow rate negatively impacted up on RT. The content of Withaferin-A was estimated as 0.03 ± 0.001 mg % w/w. The results obtained from the studies showed that method was found to be accurate, precise and validated for estimation of Withaferin-A from Ashwagandhadi lehya.

3 illus, 6 tables, 38 ref

044202   KUMAR N, SINGH A , SHARMA D K, KISHORE K (Dr. R. M. L. Institute of Pharmacy, Shahjahanpur - 242 401, Uttar Pradesh, Email: neerajsitm@yahoo.com) : Wound healing activity of methanolic extract of Arnebia benthamii. Int J Pharm Sci & Res 2020, 11(1), 328-33.

Arnebia benthamii (synonym - Microtomia benthamii) commonly known as Ratanjot or Laljari found in western Himalayan region and used as wound healer roots by local vaids and tribes. The roots of Arnebia benthamii contain a red dye that is used in various health disorders like fungal infection, inflammation, fever and coloring/flavoring agent in Indian curries. To estimate wound healing potential of root extract of Arnebia benthamii, percentage wound contraction, wound area, epithelization time, tensile strength and wound index were measured in 13 days of wound healing study. The results showed highly significant wound healing in excision as well as incision wound healing models (P<0.01). The Arnebia benthamii extract-treated wounds showed about 41 % higher wound contraction rate and 44 % increased tensile strength in comparison with negative control animals. The epithelization time decreased by 43 % and wound index value decreased by 89 % in comparison to negative control animals which indicated that methanolic root extract of Arnebia benthamii is very helpful in faster and high-quality wound healing (P < 0.05).

5 illus, 1 table, 18 ref

044201   GUPTA M, SASMAL S T , DUTTA R (Dravyaguna Dep, Institute of Post Graduate Ayurvedic Education and Research, Kolkata - 700 009, West Bengal, Email: mradu_gupta@hotmail.com) : Standardization of the hydro-alcoholic extract of ayurvedic vaginal formulation (na) by using chromatography (hptlc, hplc) and spectroscopy (uv-vis & ftir & gc-ms) methods. Int J Pharm Sci & Res 2020, 11(1), 312-27.

The research herbal formulation prepared by mixing dried stem barks of Azadirachta indica A. Juss. and Saraca asoca Roxb. in equal amounts is standardized through pharmacognostic and phytochemical studies for assessing its efficacy in the treatment of leucorrhoea/vaginitis/ excessive white discharge. Pharmacognostical analysis revealed total ash value of 9.43 % having 1.89 % acid insoluble ash, 4.62 pH and 7.70 % moisture content and presence of nitrogen and halogens. Flavonoids, tannins, carbohydrates, glycosides, saponins and fixed oils were found present in the hydro-alcoholic extracts. The results also showed a high concentration of flavonoids compounds (43.37 µg quercetin equivalent/mg) and high phenolic content (101.22 µg gallic acid equivalent/mg). UV-Visible spectroscopy scanning showed a prominent peak at 277 nm in the hydro-alcoholic extract. HPTLC analysis at 254 nm, 277 nm, and 330 nm indicated the presence of tannic acid, gallic acid, quercetin and catechol. Similarly, HPLC analysis at 277 nm suggested the presence of gallic acid, tannic acid and catechol. FTIR analysis exhibited the presence of N-H stretching, C-H stretching, N-H bending, N-O asymmetric stretching, C-C stretching, C-H rocking, C-N stretching, C-O stretching, C-H wagging, C-N stretching, C-Cl stretching, C-H bending and C-Br stretching functional groups suggesting the presence of amines/amides, alkenes, nitro group, aromatics, alcohol/ carboxylic acids/esters/ethers, alkyl halides, and aliphatic/ aromatic amines. Eluted chemicals during GC-MS revealed the presence of nimbiol; 13- Methoxypodocarpa-8, 11,13-trien-3-one; Podocarpa-8, 11, 13-triene, 14- isopropyl-13-methoxy; 8-Chloro-5-quinolinecarboxylic acid; and 7-Chloro-2- cyclohexyl-4[3H]quinazolinone which has antimicrobial, antibacterial, antiinflammatory, antifungal and analgesic properties validating the efficacy of the research formulation.

14 illus, 11 tables, 15 ref

044201   GUPTA M, SASMAL S T , DUTTA R (Dravyaguna Dep, Institute of Post Graduate Ayurvedic Education and Research, Kolkata - 700 009, West Bengal, Email: mradu_gupta@hotmail.com) : Standardization of the hydro-alcoholic extract of ayurvedic vaginal formulation (na) by using chromatography (hptlc, hplc) and spectroscopy (uv-vis & ftir & gc-ms) methods. Int J Pharm Sci & Res 2020, 11(1), 312-27.

The research herbal formulation prepared by mixing dried stem barks of Azadirachta indica A. Juss. and Saraca asoca Roxb. in equal amounts is standardized through pharmacognostic and phytochemical studies for assessing its efficacy in the treatment of leucorrhoea/vaginitis/ excessive white discharge. Pharmacognostical analysis revealed total ash value of 9.43 % having 1.89 % acid insoluble ash, 4.62 pH and 7.70 % moisture content and presence of nitrogen and halogens. Flavonoids, tannins, carbohydrates, glycosides, saponins and fixed oils were found present in the hydro-alcoholic extracts. The results also showed a high concentration of flavonoids compounds (43.37 µg quercetin equivalent/mg) and high phenolic content (101.22 µg gallic acid equivalent/mg). UV-Visible spectroscopy scanning showed a prominent peak at 277 nm in the hydro-alcoholic extract. HPTLC analysis at 254 nm, 277 nm, and 330 nm indicated the presence of tannic acid, gallic acid, quercetin and catechol. Similarly, HPLC analysis at 277 nm suggested the presence of gallic acid, tannic acid and catechol. FTIR analysis exhibited the presence of N-H stretching, C-H stretching, N-H bending, N-O asymmetric stretching, C-C stretching, C-H rocking, C-N stretching, C-O stretching, C-H wagging, C-N stretching, C-Cl stretching, C-H bending and C-Br stretching functional groups suggesting the presence of amines/amides, alkenes, nitro group, aromatics, alcohol/ carboxylic acids/esters/ethers, alkyl halides, and aliphatic/ aromatic amines. Eluted chemicals during GC-MS revealed the presence of nimbiol; 13- Methoxypodocarpa-8, 11,13-trien-3-one; Podocarpa-8, 11, 13-triene, 14- isopropyl-13-methoxy; 8-Chloro-5-quinolinecarboxylic acid; and 7-Chloro-2- cyclohexyl-4[3H]quinazolinone which has antimicrobial, antibacterial, antiinflammatory, antifungal and analgesic properties validating the efficacy of the research formulation.

14 illus, 11 tables, 15 ref

044200   SHARMA P, TAILANG M (Pharmaceutics Dep, Shri Ram Coll of Pharmacy, Morena - 476 444, Madhya Pradesh, Email: pankajsharma223@gmail.com) : Design, optimization and evaluation of buccal drug delivery system of propranolol for hypertension treatment. Int J Pharm Sci & Res 2020, 11(1), 301-11.

The main objectives of the present study were to design, optimization and evaluation of buccal drug delivery system of propranolol for hypertension treatment. Propranolol is non-selective β-adrenergic blockers. It shows first-pass metabolism so its bioavailability is decreased and its absolute bioavailability is only about 26 %. The buccal tablets of propranolol formulated, by using different mucoadhesive polymers such as sodium crosscarmilose sodium, PVP K30, and HPMC K15M. F8 was containing 18.18 % PVPK30, 10.90 % HPMC K15M showed desired drug release within 6 h to above batches. The dissolution profile of formulated batch F1 to F8 at the end of 6 h was found in the range of 83.03 to 94.69 % in phosphate buffer pH 6.8. From the results, it was found that formulation F8 was shown most similar dissolution profile because the similarity value was found to be above 90 %. The swelling index was found higher in formulation F9 80.15 % swelling observed because of higher concentration of PVP K30 and HPMC K15M. The results indicate that out of two bioadhesive polymers PVP k 30 along with HPMC K15M in different concentration with fraction batches code F1 to F9 having PVP K30 have shown more bioadhesive strength than HPMC K15M. Statistical optimization of propranolol tablet was done by design expert software, version 8.0.7.1. No significant changes were observed in the physical appearance, mucoadhesive strength and drug content of the formulations kept both at room temperature (RT) and accelerated conditions (45 °C, 75 % RH) for 1 month.

5 illus, 19 tables, 17 ref

044199   SAJINI R J, PREMAS, NIVEDITHA S, NITHYA S, PAVITHRA G M, NIVETHA V (Pharmaceutical Chemistry Dep, Sri Ramachandra Institute of Higher Education and Research, Chennai - 600 116, Tamil Nadu, Email: karthikjasmin0214@gmail.com) : Hplc method development and validation for estimation of rifabutin in bulk and capsule dosage form. Int J Pharm Sci & Res 2020, 11(1), 297-300.

A selective, accurate, HPLC method was developed by this study for the determination of rifabutin in bulk and capsule dosage form. This method was developed by SHIMADZU LC-2010 HT using C18 column in solvents methanol: acetonitrile: ammonium acetate buffer (50: 45: 05) as mobile phase. At 1.0 ml/min flow rate the mobile phase was pumped, and the sample was detected at 278 nm. For standard rifabutin the retention time was 4.8 min. The method was validated for analytical standards such as linearity, accuracy, precision, and robustness. In a wide range of 5-25 (µg/ml) the linearity was observed. The method was validated, and a recovery study indicates accuracy of this method.

5 illus, 5 tables, 15 ref

044198   PRASANNA J L , BABU A M S, JYOTHI C H, RAO T M (Pharmaceutics Dep, A. M. Reddy Memorial Coll of Pharmacy, Narasaraopet - 522 601, Andhra Pradesh, Email: nuniprabhuprasanna@gmail.com) : Method development for estimation of diclofenac sodium in a chocolate dosage form. Int J Pharm Sci & Res 2020, 11(1), 292-6.

A simple, rapid, precise, sensitive and reproducible Reverse Phase High-Performance Liquid Chromatography (RPHPLC) method has been developed for the quantitative analysis of Diclofenac sodium in the chocolate dosage form. Chromatographic separation of Diclofenac sodium was achieved on waters alliancee2695, by using waters symmetry C18, 150 mm × 4.6 mm, 3.5 µm, column and the mobile phase containing 0.1 % formic acid & ACN in the ratio of 30:70 % v/v. The flow rate was 1.0 ml/min; detection was carried out by absorption at 275 nm using a photodiode array detector at ambient temperature. The calibration curve was linear over the range of 5-75 µg/ml. The number of theoretical plates and tailing factor for Diclofenac sodium was NLT 2000 and were not more than two, respectively. The proposed method was validated according to ICH guidelines. The method was found to be simple, economical, suitable, precise, accurate & robust method for quantitative analysis of Diclofenac sodium and study of its stability.

5 illus, 6 tables, 14 ref

044196   SAWATDEE S, ATIPAIRIN A (Walailak Univ, Nakhon Si Thammarat, 80161, Thailand, Email: somchai086@hotmail.com) : Formulation and stability evaluation of cream containing Chromolaena odorata and Centella asiatica leaf extracts. Int J Pharm Sci & Res 2020, 11(1), 282-7.

Chromolaena odorata was extracted by ethanol/water. Centella asiatica was extracted by methanol. A cream containing C. odorata and C. asiatica extracts was formulated and evaluated for its physicochemical properties and stability. C. odorata and C. asiatica were extracted and their respective active compounds scutellarein tetramethyl ether and asiaticoside were determined as bioactive compounds using HPLC. Creams were prepared using 5 % C. odorata and 1 % C. asiatica extracts and tested for their appearance, pH, and viscosity. Stability was evaluated under accelerated conditions using six hot/cold cycles and after long-term storage at 30 $°$C/75 % RH for 3 months. The content of scutellarein tetramethyl ether in C. odorata extract was 0.13 ± 0.02 % w/w and the content of asiaticoside in the C. asiatica extract was 0.35 ± 0.04 % w/w. Contents of scutellarein tetramethyl ether and asiaticoside in the cream formulation were 98.25 ± 0.43 % and 102.16 ± 0.22 %, respectively. The cream formulations containing the extracts had a good appearance and were non-greasy and easily applied, with a pH value of 5.4 ± 0.1 and viscosity of 1604 ± 257 poises determined at shear rate 0.08 s-1 . No changes in physical and chemical properties occurred during storage. These findings indicate that this formulation of 5 % C. odorata and 1 % C. asiatica extract is stable and suitable for further testing as a topically applied product.

1 illus, 2 tables, 22 ref

044195   DARMWAL N, SINGH B K (Pharmaceutical Sciences Dep, Kumaun Univ Campus, Nainital - 263 136, Uttarakhand, Email: bksinghku@gmail.com) : High-throughput structure based virtual screening targeting cns for inhibited acetylcholinesterase reactivation. Int J Pharm Sci & Res 2020, 11(1), 275-81.

Organophosphorus (OP) nerve agents blocks acetylcholinesterase and do not allow the degradation of acetylcholine. Post-treatment of organophosphate poisoning involves the treatment with oxime reactivators as an antidote, which will dephosphorylate the phosphate bond between enzyme and nerve agent. Due to CNS permeability failure of these oximes, the introduction of low molecular non-oximes has become a challenging role for reactivation of inhibited acetylcholinesterase. In-silico high-throughput structure-based virtual screening and docking by using LOPAC database targeting CNS for inhibited acetylcholinesterase reactivation. For the identification of an active site of AChE enzyme and high throughput virtual screening, Inventus™ software was being used. ADME analysis for the selection of leads which can follow up Lipinski rule of 5 and CNS parameters for permeation. Further docking studies of selected lead candidates was done using Schrodinger software. By taking various CNS parameters into consideration hits were selected. For further refinement docking was performed, and the best lead obtained with glide XP docking score -11.656 Kcal/mol. The best lead candidates passed CNS permeation parameters range and have shown well binding with Acetylcholinesterase enzyme as that of standards.

1 illus, 2 tables, 16 ref

044194   BALARAK D , ZAFARIYAN M, CHANDRIKA K (Biotechnology Dep, Koneru Lakshmaiah Education Foundation, Guntur - 522 502, Andhra Pradesh, Email: kkchandrika@kluniversity.in) : Adsorption of ciprofloxacin from aqueous solution onto Fe₃o₄/ graphene oxide nanocomposite. Int J Pharm Sci & Res 2020, 11(1), 268-74.

In this research, ciprofloxacin adsorption (CIP) onto graphene oxide synthesized with Fe₃O₄ (Fe₃O₄-GO) was applied via various adsorbent dose, contact time, temperature and initial CIP concentration. The results showed that the percentage removal of CIP decreases from 98.1 to % 77.4, as the CIP concentration increases from 25 to 200 mg/L. Also, the amount of CIP adsorbed per unit mass of adsorbent increased from 49.25 to 309.6 mg/g with increasing in CIP concentration from 25 to 200 mg/L. The results showed that the adsorption was accurately represented by the pseudo-second-order model. Under different temperature, the CIP maximum adsorption on Fe₃O₄-GO calculated by pseudo-second-order kinetic model and were 197 mg/g (273 K), 191.6 mg/g (288 K), 182.2 mg/g (303 K) and 172.6 mg/g (318 K). Also, the results showed the existence of three steps during the adsorption process. The first stage was the transport of CIP molecule from the adsorbents external surface to the pores of the adsorbent internal structure. The second stage is the transport of CIP molecule from the adsorbent external surface to the pores of the adsorbent internal structure. The third stage is the adsorption of CIP molecule on the interior surface of the adsorbent. The results suggest that Fe₃O₄-GO could be employed as an effective material for the removal of CIP from aqueous solutions.

5 illus, 2 tables, 45 ref