IR@CMERI - The Central Mechanical Engineering Research Institute (CSIR)
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On learning-based approaches in power electronics engineering curriculum: A high switching inchworm motor drive case study
No full textIn industrial electronics domain, power electronics students should have an optimum hardware competence. This study presents the application of computer-aided design and experimental hands-on exposure for efficient teaching of power electronics engineering curriculum. Application design of the proposed research centers around effective model of high switching frequency driver circuit for a capacitive piezoelectric inchworm motor based on learning techniques. The sample space comprise 50 undergraduate students, divided into two equal groups, Group A and Group B. Outcome validations testify the pivotal role of the designed course for the optimized piezoelectric driver hardware circuit design with near equivalent characteristics as obtained in simulation model. An evaluation survey was carried out to find if there is a change in attitude of students toward power electronics and allied subjects after attending the program. At the end of the course, opinion of the students were recorded and it was found that the attitude of the students who took the course differed significantly. The differentiation was in favor of the group having undertaken the course with a 91.5% positive response
Catalytic conversion of CO2 to biofuel (methanol) and downstream separation in membrane-integrated photoreactor system under suitable conditions
No full textA heterogeneous photocatalyst has been developed using sono-chemical assisted sol-gel method by maintaining aweight ratio of 1:2:3 for hydrogen exfoliation graphene, titanium oxide andcopper sulphateand exhaustively characterized. Rigorous experimentations have been done using newly developed heterogeneous photocatalyst for efficient capturing and maximum conversion of carbon di oxide to methanol by mutual effects of governing conditions, like as catalyst dose, pH, CO2 flow rate and temperature. Optimization study has been carried out employing a statistical approach of response surface methodology which reveals the maximum methanol productivity and yield. Approximately, 134 g/Lh of productivity and 40 mg/gcatof yield were found after 3 h of illumination under UV in an annular type Pyrex reactor at an optimum catalyst dosage of 10 g/L, CO2 flow rate of 3 L/m, pH of 3, and process temperature of 50 °C. By the judicial integration of flat-sheet cross flow microfiltration membrane module for catalyst separation and recycle, a steady state permeate flux 145 L/m2h was achieved at an applied pressure of 3 bar and cross-flow feed rate of 700 L/h
Lubrication of dry sliding metallic contacts by chemically prepared functionalized graphitic nanoparticles
No full textUnderstanding the mechanism of precision sliding contacts with thin, adherent solid nano lubricating particle films is important to improve friction and wear behavior and ensure mechanical devices have long service lifetimes. Herein, a facile and multistep approach for the preparation of graphene oxide (GO) is presented. Subsequently, surface modification of as-synthesized GO with octadecyl amine (ODA) is performed to prepare hydrophobic GO-ODA and with 6-amino-4-hydroxy-2-naphthalenesulfonic acid (ANS) to prepare amphoteric GO-ANS through a nucleophilic addition reaction. X-ray diffraction and ultraviolet-visible, Fourier transform infrared, and Raman spectroscopy provide significant information about the reduction of oxygen functionalities on GO and the introduction of new functionalities in GO-ODA and GO-ANS. The effects of particle functionalization for the improved control of particle adhesion to the tribocontact have been studied. Wettability and thermal stability were determined using the water contact angle, and atomic force microscopy and differential scanning calorimetry (DSC) were used to characterize particle adhesion to the tribocontact. The tribological performances of the particles have been investigated using macro- and micro-tribometry using pin/ball-on-disc contact geometries. The influence of particle functionalization on the contact pressure and sliding velocity was also studied under rotating and reciprocating tribo-contact in ambient conditions. With an increase in the contact pressure, the functionalized particles are pushed down into the contact, and they adhere to the substrate to form a continuous film that eventually reduces friction. Amphoteric GO-ANS provides the lowest and most steady coefficient of friction (COF) under all tested conditions along with low wear depth and minimal plastic deformation. This is because particles with superior wetting and thermal properties can have better adherence to and stability on the surface. GO-ANS has a superior ability to adhere on the track to form a thicker and more continuous film at the interface, which is investigated by field emission scanning electron microscopy, energy dispersive spectroscopy, and Raman analysis
Optimal driving based trip planning of electric vehicles using evolutionary algorithms: A driving assistance system
No full textThe existing driving assistance systems (DAS) are not capable to manage the electric vehicle (EV) problems namely insufficiency of charging stations and inadequate range. A novel DAS is presented here to extend the range and overcome other EV drawbacks by suggesting the driver an optimal driving strategy (ODS) continuously throughout trip performing. ODS is decided by solving a multi-objective optimization problem (MOOP), subsequently adopting a multi-criterion decision making technique. Implementation of the DAS in real application requires both better optimization results and low computational time. A study was carried out to investigate the DAS performance with four contending evolutionary algorithms (EAs), NSGAII (a non-dominated sorting multi-objective genetic algorithm), PESA (Pareto envelope-based selection algorithm), PAES (Pareto archived evolution strategy), and SPEA 2 (Strength Pareto evolutionary algorithm). After an initial investigation of EA performances based on different matrices, NSGAII and PESA were found to be most suitable. The natures of decision variables in the Pareto-optimal solutions were analyzed. After an extensive analysis based on different micro-trip structures, it was found that without considering the computational time, PESA solutions possess better convergence and diversity properties than NSGAII solutions. Various approaches were adopted to minimize DAS computation time considering both NSGAII and PESA without significantly compromising the solution’s optimality
Physico-mechanical properties of tamarind pod shell-based composite
No full textThe main objective and novelty of this study is to investigate the effect of particle size and alkali treatment on physical, mechanical properties of tamarind pod shell (TPS)-reinforced epoxy composites. The treated and untreated composites were fabricated with different particle sizes with TPS content of 10 wt%. The mechanical, physical, and morphological properties of specimens were investigated. It was revealed that the density and mechanical properties of the treated and untreated composites increased with the decrease in the particle size; whereas, the water absorption percentage and void content decreased for the same. The treated composite with the particle size of 75 μm exhibited the maximum tensile, flexural, and compressive strength. Further, the multiscale finite element (FE) model was developed using the Digimat-FE software to simulate the tensile behavior of composites with different particle size. The simulation results revealed that the stress concentration level was more in the vicinity of the voids, and the higher stress concentration was observed in the matrix phase with the increase in particle size. Also, it was found that the predicted results from the multiscale FE model showed a good agreement with the experimental results. The results suggested that the TPS filled epoxy composites have potential utility in the fields of automotive interior panels, particulate board panels, household goods, packaging materials, building partitions, and many other applications
Within-journal self-citations and the Pinski-Narin influence weights
No full textThe Journal Impact Factor (JIF) is linearly sensitive to self-citations because each self-citation adds to the numerator, whereas the denominator is not affected. Pinski and Narin (1976) Influence Weights (IW) are not or marginally sensitive to these outliers on the main diagonal of a citation matrix and thus provide an alternative to JIFs. Whereas the JIFs are based on raw citation counts normalized by the number of publications in the previous two years, IWs are based on the eigenvectors in the matrix of aggregated journal-journal citations without a reference to size: the cited and citing sides are normalized and combined by a matrix approach. Upon normalization, IWs emerge as a vector; after recursive multiplication of the normalized matrix, IWs can be considered a network measure of prestige among the journals in the (sub)graph under study. As a consequence, the self-citations are integrated at the field level and no longer disturb the analysis as outliers. In our opinion, this independence of the diagonal values is a very desirable property of a measure of quality or impact. As an example, we elaborate Price’s (1981b) matrix of aggregated citation among eight biochemistry journals in 1977. Routines for the computation of IWs are made available at http://www.leydesdorff.net/iw
A review on synthesis of zirconia toughened alumina (ZTA) for cutting tool applications
No full textZirconia toughened alumina (ZTA) are among those materials which have high demand in the manufacturing industries, due to its application as cutting tool material for machining of high strength steel alloys. The properties such as high hardness, high wear resistance, chemical inertness at room temperature, high hot hardness, rapture strength, moderate heat resistance and compressive strength make its application superior than other cutting tool materials. The said superior properties of ZTA have been achieved when particles of yttria stabilized zirconia are uniformly dispersed inside alumina matrix. Therefore, to achieve the desired properties of ZTA, the first step is to develop well homogenized powders. The powders are developed through various synthesis processes such as sol-gel, hydro thermal synthesis, solvo thermal synthesis, co precipitation and chemical vapour deposition (CVD). Hence, an in-depth literature review has been made towards the synthesis processes of ZTA. The synthesized powders of ZTA are used to fabricate cutting inserts using powders metallurgy processes. Therefore, a rigorous analysis has been carried out towards the development of cutting inserts using ZTA powders. A subsequent analysis has also been made to show the effect of additive inside ZTA matrix on the performance of cutting inserts
An Adaptive Frequency-Fixed Second-Order Generalized Integrator-Quadrature Signal Generator Using Fractional-Order Conformal Mapping Based Approach
No full textThe frequency-fixed second-order generalized integrator-based quadrature signal generator (FFSOGI-QSG) has been widely used in grid synchronization applications. The major limitations of using this technique are the unequal amplitudes of in-phase and quadrature-phase signals under grid frequency variation, which causes double-frequency oscillatory and offset errors in FFSOGI-based phase-locked loop output. To overcome the issues, in this letter, a modified complex analysis of FFSOGI-QSG using fractional-order-based conformal mapping approach has been presented, and an adaptive FFSOGI-QSG (AFFSOGI-QSG) is proposed. The proposed AFFSOGI-QSG can adapt itself to the grid frequency variations through the adjustment of single tuning parameter, i.e., fractional-order gain. The proposed structure is also found to inherit the simplicity of the FFSOGI-QSG without changing the order of the system while demonstrating an improved disturbance rejection capability under various grid disturbances. Performance of the proposed AFFSOGI-QSG is finally validated against some well-known SOGI-QSGs using numerical results obtained from the MATLAB and experimental results from the dSPACE DS1104 hardware
Sensing of ethanol and other alcohol contaminated ethanol by conducting functional poly(o-phenylenediamine)
No full textPoly(o-phenylenediamine) with amine (–NH2) functional group substitutions was chemically synthesized from the monomer o-phenylenediamine using ammonium persulfate oxidant in sulphuric acid medium. The synthesized polymer was soluble in organic solvent like dimethyl sulfoxide (DMSO), dimethyl formamide, etc. The sensing layer was fabricated by a simple drop coating method using the polymer solution in DMSO and the layer was doped with sulfuric acid doping using optimized doping conditions. An average resistance of the doped polymer layer was observed as 2–5 MΩ. The doped conducting polymer layer was used as chemiresistor for the successful sensing of ethanol and methanol or isopropanol contamination in ethanol. The response of doped polymer layer was examined under continuous flow of methanol, ethanol, isopropanol, ethanol/methanol, and ethanol/isopropanol with air mixture at room temperature (25 ± 3 °C) and room humidity (65 ± 5%). The sensing mechanism for doped functional poly(o-phenylenediamine) through –NH2 group substitutions was explored with the help of various standard characterizations
A TG-FTIR investigation on the co-pyrolysis of the waste HDPE, PP, PS and PET under high heating conditions
No full textThe present study relates to the investigation of degradation of polymers such as HDPE, PP, PS and PET individually and in mixed forms. Eleven different mixture combinations were analyzed via TG Analysis to determine their degradation behavior individually and in mixed forms. FTIR analysis of the raw polymers was performed to investigate the presence of different functional groups in the sample. Online TG-FTIR analysis was performed to investigate the functional groups present in the volatiles fractions during single component pyrolysis and the interaction of polymers during co-pyrolysis was analyzed, compared and reported. Also, a real-world post consumer mixed waste was also analyzed and compared. During the co-pyrolysis of HDPE with PP and PS, the degradation of PP was delayed whereas PS reduced the degradation temperature of HDPE. In the case of degradation of PS with PP and PET, the increase in degradation temperature was reported whereas, in the case of PET and HDPE mixture, the degradation temperature of HDPE was reduced. During the interaction of PP and PET mixed degradation, PET degradation temperature was delayed. During the FTIR analysis a large amount of alkanes, alkenes, aromatics groups were observed during the degradation of HDPE, PP and PS whereas in case of PET the presence of oxygenated groups is observed. During the mixed degradation, the presence of PET in the sample caused the formation of oxygenated groups by reducing the absorption intensity of other groups or by disappearing the groups. Compounds such as benzoic acid, CO and CO2 was detected during the degradation of PET whereas in other polymers a large amount of methane or methylene group is observed. Overall during the degradation of mixed polymer mixture presence of PET played a vital role in the formation of light gas fractions. Even though a numerous investigation on co-pyrolysis of polymers were available, there is still not sufficient information of interaction of polymers with each other, especially with PET. This article attempts to fill this gap