Experimental and computational studies of imidazolium based ionic liquid 1-methyl- 3-propylimidazolium iodide on mild steel corrosion in acidic solution

Corrosion inhibitive property of ionic liquid 1-Methyl-3-propylimidazolium iodide (MPII) on Mild Steel in 1 M H2SO4 was investigated by experimental and computational Studies. The inhibition efficiency of inhibitor MPII at various concentrations, temperature and time duration were studied by gravimetric measurements, potentiodynamic polarization techniques, electrochemical impedance spectroscopy (EIS), surface studies and computational studies. The results from potentiodynamic polarization studies revealed that inhibitor 1-Methyl- 3-propylimidazolium iodide acts as a mixed type inhibitor with a high inhibition efficiency of 91% at 298 K. Adsorption of the inhibitor on the surface of mild steel follows the Langmuir adsorption isotherm. The mechanism of adsorption was also validated by quantum chemical studies. Morphology and topography of the Mild Steel surface with and without the inhibitor were investigated by SEM. Thermodynamic parameters for adsorption like adsorption equilibrium (${K}_{{\rm{ads}}}$), ${\rm{\Delta }}{H}_{{\rm{ads}}},$ ${\rm{\Delta }}{S}_{{\rm{ads}}},$ Free energy of adsorption i.e. ΔGads were also calculated so as to project the mechanism of adsorption. Computational data obtained from the Density functional theory (DFT) were used to acquire detailed theoretical insights. Appreciably Electrochemical impedance spectroscopy, Molecular dynamic simulation and quantum chemical calculation confirms the interaction of inhibitor with metal which leads to increases in inhibition efficiency

A Novel Methodology for Spark Gap Monitoring in Micro-EDM Using Optical Fiber Bragg Grating

Micro-electric discharge machining (micro-EDM) is the most considerable micro-manufacturing process used to engineer miniaturized features on any high temperature resistive hard material. The machining parameters of micro-EDM are very stochastic in nature. The spark gap measure acts as a vital parameter that correlates with other process parameters for enhancement of the material removal rate (MRR) in micro-EDM. The real-time actual measurement of the spark gap between the electrodes is highly challenging and is limited due to the small gap measure. This article is about the development of a novel sensing technique for spark gap measurement, based on a fiber Bragg grating (FBG) sensor. The sensing system is developed on a cantilever structure bonded with the FBG sensor, for performing accurate spark gap measurements with the displacement measurement of the tool electrode. The deflection on the cantilever during spark gap generation is translated into strain variations, as monitored by the FBG bonded over it. Experimental trials are conducted on the micro-EDM setup with the cantilever beam-based displacement sensing with a sensitivity of 10 μm/pm. Real-time spark gap data obtained by FBG are in the range of 1.1-18.6 μm and are validated against a precision measuring instrument. This sensing technology employed for micro-EDM spark gap measurement establishes a novel technique in the micro-machining field and formulates a smart system

Catalytic conversion of CO2 to biofuel (methanol) and downstream separation in membrane-integrated photoreactor system under suitable conditions

A 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

A review on synthesis of zirconia toughened alumina (ZTA) for cutting tool applications

Zirconia 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

Optimal driving based trip planning of electric vehicles using evolutionary algorithms: A driving assistance system

The 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

Investigation of the mechanical performance of carbon/polypropylene 2D and 3D woven composites manufactured through multi-step impregnation processes

In this work, pre-impregnation techniques including Dr. Ernst Fehrer (DREF) spinning and electrostatic powder coating were used to negate the poor impregnation of highly viscous thermoplastics. The DREF spun hybrid yarns and electrostatic spray coated towpregs were woven into 2D and 3D fabrics and subsequently consolidated to yield two variations of 2D and four variations of 3D composites including 3D angle inter-lock and 3D orthogonal weave. The 2D composites possessed higher tensile and flexural strength than the 3D composites. However, better notch impact properties were observed for 3D orthogonal weave. The closer wrapping in 3D orthogonal slightly improves the shock absorption capability of the composite than the angle interlock composite. Composites made from powder coated towpregs performed better than composites made from DREF spun hybrid yarns, minimizing the effect of the weave pattern. Porosity was a common feature of composites manufactured from DREF spun yarns as observed from micro-CT images

Three-dimensional phase field simulation of spheroidal grain formation during semi solid processing of Al-7Si-0.3 Mg alloy

The present study reports development and application of a three dimensional phase field (PF) model, to investigate the microstructure evolution mechanism responsible for generation of spheroidal primary Al grains, associated with cooling slope processed semi solid slurry of A356 aluminium alloy. The cooling slope rheoprocessing technique involves solidification of flowing melt on an inclined slope surface, where gravity assisted fluid flow and shearing action between the flowing melt and the slope surface causes formation of near spherical primary solid fragments, and subsequent isothermal globularisation of the evolving primary solid. The present PF model implements a seed density based nucleation model. The seed density requirements to simulate microstructure evolution for different simulation/melt treatment conditions of cooling slope processing have been estimated based on initial experimentation. The simulated micrograph of slope exit state i.e, at the end of cooling slope processing has been used to estimate the number density and average size of constituent α-Al grains of the generated slurry, at slope exit state. The values obtained are fed subsequently as input parameters to simulate post slurry generation isothermal globularisation process. The model predictions are validated experimentally, thus establishing its capability to predict the characteristics of semisolid slurry at different stages of cooling slope rheoprocessing, in terms of solid content (volume fraction), diameter, density, and shape factor (sphericity) of nucleated primary Al grains

Letter to the Editor: Comments on the paper of Batagelj—on fractional approach to analysis of linked networks

We examine the role of count conservation when derived network matrices are obtained from linked network matrices using an outer product decomposition. It is seen that a full counting operation conserves the count of pathways between nodal variables while a fractional counting operation conserves the count of the nodal variable. We use the cases of co-referencing (bibliographic coupling) and co-citation with a simple citation network to illustrate the ideas

Tribological Property Investigation of Self-Lubricating Molybdenum-Based Zirconia Ceramic Composite Operational at Elevated Temperature

Three mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with 0.5 wt% of magnesium oxide (MgO) and 6 wt% of molybdenum (Mo) were prepared by the pressureless sintering process, and the friction and wear behavior of the ceramic composite were studied against the alumina disc. Tribological tests were carried out both at room temperature as well as at an elevated temperature (500 °C). The result revealed that a substantial reduction of ∼50% in the friction coefficient and ∼31% reduction in the wear rate were achieved while 6 wt% Mo was added into the 3Y-TZP matrix operational at 500 °C. No significant tribological influence was observed with the addition of Mo at the normal operating temperature. The minimum coefficient of friction and low specific wear rate were achieved because of the formation of MoO3 in between the mating surfaces at elevated temperature. The worn surfaces were characterized by means of field emission scanning electron microscopy (FESEM). The formation of MoO3 phases was identified by wear debris analysis which was performed with the help of X-ray photoelectron spectroscopy (XPS)

Pretreatment of polysaccharidic wastes with cellulolytic Aspergillus fumigatus for enhanced production of biohythane in a dual-stage process

Biological pretreatment of polysaccharidic wastes (PWs) is a cost-effective and environmentally friendly approach to improve the digestibility and utilization of these valuable substrates in dual-stage biohythane production. In order to reduce the prolonged incubation time and loss of carbohydrate during the pretreatment of PWs with Aspergillus fumigatus, a systematic optimization using Taguchi methodology resulted in an unprecedented recovery of soluble carbohydrates (362.84 mg g−1) within 5 days. The disruption and fragmentation of lignocellulosic structures in PWs, and possible saccharification of cellulose and hemicellulose components, increased its digestibility. A dual-stage biohythane production with pretreated PWs showed increased yield (214.13 mL g−1 VSadded), which was 56% higher than the corresponding value with the untreated PWs. This resulted in 47% higher energy recovery as biohythane in pretreated biomass compared to untreated biomass. Optimized fungal pretreatment is, therefore, an effective method to improve the digestibility of PWs and its subsequent conversion to biohythane