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The main objective of this experimental work is to analyze and measure the form tolerances namely flatness and squareness while machining a meso deep hole in EDM on Inconel-718 material plate.

The experiments were performed on 15 amps rated SPARKONIX-EDM as per DOE (design of experiments). Kerosene was used as a dielectric along with constant pressure of 0.2 kg/cm² for all trial runs. The currents T_on and T_off were selected as process constraints to conduct experimental trials. The MRR, EWR, machining time and form tolerances were considered as output responses. The experimental outcomes were optimized by hybrid optimization using Taguchi and GRA (grey relational analysis) method.

The EDM process parameters for Ni-based super alloy namely Inconel-718 had optimized by using GRA method coupled with Taguchi method. The optimum solution has been calculated for MRR, EWR, machining time and form tolerances namely squareness and flatness. The optimized parameters for the output responses in EDM process are Peak current (Ip) 12 Amps, 400 µs T_on (pulse on time) and 10 µs T_off (pulse off time). An attempt had also been made to attain Max. and Min. Evaluation of MRR and form tolerances, respectively. The attained optimum outcomes had also been examined through a real experiment and established to be satisfactory.

This article will facilitate the defense, aerospace and EDM industries to improve their productivity with closer tolerances.

The optimized parameters by multi-parametric optimization showed the considerable improvement in the process and will facilitate the defense, aerospace and EDM industries to improve their productivity with closer tolerances.

The purpose of this paper is to examine the performance parameters of WEDM to improve the productivity and material removal rate (MRR) with a high surface finish of high chromium-high carbon dies steel.

The experiments were performed on AGIE CUT 220 CNC WEDM. High chromium-high carbon dies steel (D3) was used in the form of a rectangular plate. The workpiece and the brass wire having diameter ɸ 0.25 mm had linked up with +ve and –ve polarity in the DC power source, respectively. De-ionized water having a conductivity level of 0.6 µs/cm was used as the dielectric medium. The dielectric fluid was flushed from the top and bottom nozzles and material was submerged in the dielectric.

The WEDM process parameters for D3 die steel had optimized by using Grey relational analysis method couples with Taguchi method. The optimum solution has been calculated for MRR, cutting speed (Cs), machining time and surface roughness (SR) (Ra value). A fuzzy logic model using Matlab was developed for the prediction of performance parameters, namely MRR, cutting speed (Cs), machining time (M/c time) and SR with respect to changes in input parameters.

The fuzzy model shows the 96.19 percent accuracy between the experimental values and the predicted values.

The optimized parameters by multi-parametric optimization method showed considerable improvement in the process and will facilitate the WEDM, tool and die industries, defense and aerospace industries to improve the productivity with the higher surface finish.

This manuscript represents valid work and the authors have no conflict of interests. The attained optimum outcomes had also been examined through a real experiment and established to be satisfactory.

Maps the strategic 50‐year journey of Singapore Airlines (SIA) to identify the underlying factors that account for its extraordinary success and world‐class stature. Both longitudinal and comparative research methodologies were employed. For the former, the approach taken was to systematically research SIA’s historical development over the entire 50‐year time period. SIA was studied from its very beginning and through all phases of its development to the present day. For the latter, SIA was compared with and benchmarked against other airlines. Its unique and successful product/service differentiation strategy, epitomised by the ephemeral Singapore Girl, has turned out to be enduring and difficult‐to‐match over the past 25 years and still shows no signs of letting up.

The purpose of this paper is to explore Singaporeans’ view to a multicultural neighbourhood, specifically, their views on the Ethnic Integration Policy (EIP), a housing policy that promotes residential desegregation, and whether this policy has engendered a positive perspective to residential diversity.

A grounded theory approach is used to answer the following research questions: how do Singaporeans feel about residential diversity? Does the EIP influence attitudes to residential segregation in Singapore? What do these attitudes mean for governments and policymakers around the world? The research involved focus group discussions with 27 Housing and Development Board real estate agents, in order to tap onto their vast network of clients and better understand the prevailing sentiments on the ground.

The two major considerations when Singaporeans choose a flat are its price and location. Within the confines of these two factors, however, other considerations like race, nationality and the socio-economic makeup of a neighbourhood will influence their decisions.

These considerations can be condensed into the factors of constrained choice and voluntary segregation. By limiting the impact of voluntary segregation, the EIP can be credited with bridging the racial divide. However, with constrained choice being unaddressed by the policy, the emerging formation of a class divide is an unintended consequence.

Because almost all developed economies are culturally plural, understanding Singapore’s approach to residential desegregation offers insights as to how other countries may learn from the Singapore experience in managing and encouraging multiculturalism, especially since ethnic residential concentration can reduce the formation of strong social relationships.

The purpose of this paper is to analyze and optimize the roller burnishing process parameters using the design of experiments and grey relational analysis (GRA).

In this experimental work, the carbide burnishing tool has been selected for the machining of AISI-1040 high carbon steel to get better product quality and satisfactory machining characteristics. The material surface condition while machining, burnishing tool speed, feed rate, depth of penetration and No. of passes have been selected as process constraints to conduct experimental trials.

The surface roughness (SR) and surface hardness were considered as output responses. The experimental outcomes optimized by multi-parametric optimization showed considerable improvement in the process. The roller speed and number of passes are the most significant parameters for surface hardness, whereas the surface condition and roller penetration depth have the most significance on SR.

The GRA method shows the 0.03376 improvement in grey relational grade between the experimental values and the predicted values.

The experimental outcomes optimized by multi-parametric optimization showed the considerable improvement in the process and will facilitate steel industries to enhance and improve productivity while burnishing high carbon steel (AISI-1040).

This research represents valid work, and the authors have no conflict of interests.

In many of today’s manufacturing industries, such as automobile, aerospace, defence, die and mould making, medical and electrical discharge machining (EDM) has emerged as an effective material removal process. In this process, a series of discontinuous electric discharges is used for removing material from the workpiece in the form of craters generating a replica of the tool into the workpiece in a dielectric environment. Appropriate selection of the tool electrode material and combination of input parameters is an important requirement for performance enhancement of an EDM process. This paper aims to optimize an EDM process using single-valued neutrosophic grey relational analysis using Cu-multi-walled carbon nanotube (Cu-MWCNT) composite tool electrode.

This paper proposes the application of grey relational analysis (GRA) in a single-valued neutrosophic fuzzy environment to identify the optimal parametric intermix of an EDM process while considering Cu-MWCNT composite as the tool electrode material. Based on Taguchi’s L9 orthogonal array, nine experiments are conducted at varying combinations of four EDM parameters, i.e. pulse-on time, duty factor, discharge current and gap voltage, with subsequent measurement of two responses, i.e. material removal rate (MRR) and tool wear rate (TWR). The electrodeposition process is used to fabricate the Cu-MWCNT composite tool.

It is noticed that both the responses would be simultaneously optimized at higher levels of pulse-on time (38 µs) and duty factor (8), moderate level of discharge current (5 A) and lower level of gap voltage (30 V). During bi-objective optimization (maximization of MRR and minimization of TWR) of the said EDM process, the achieved values of MRR and TWR are 243.74 mm³/min and 0.001034 g/min, respectively.

Keeping in mind the type of response under consideration, their measured values for each of the EDM experiments are expressed in terms of linguistic variables which are subsequently converted into single-valued neutrosophic numbers. Integration of GRA with single-valued neutrosophic sets would help in optimizing the said EDM process with the Cu-MWCNT composite tool while simultaneously considering truth-membership, indeterminacy membership and falsity-membership degrees in a human-centric uncertain decision-making environment.

Magnesium alloys are becoming prominent as an alternative to the permanent biomedical implants. In present work, electric discharge drilling (EDD) process has been investigated and optimized for ZM21 Mg alloy that can be used for producing perforated bone implants having geometrically precise micro holes.

Planning of experiments has been carried out in accordance to the Taguchi mixed L18 orthogonal array (OA). The hole overcut (HO), circularity at entrance (Cent) and circularity at exit (Cext) of drilled micro holes were measured as response characteristics during experimentation corresponding to different settings of EDD input parameters. For optimizing multiresponse characteristics, the hybrid approach of grey relational analysis, regression analysis and particle swarm optimization has been implemented.

It is found from hybrid approach that brass electrode along with Ip; 3 Amp, Ton; 50 µs and Toff; 52 µs outperformed over all other parametric settings against the collective result of response characteristics. The experimental values of response characteristics at suggested optimized setting are HO: 93.48 µm; Cent: 0.988 and Cext: 0.992, respectively.

The optimization of EDD process for developing perforated Mg alloy bone implants, using hybrid approach is still missing.

It has been forecast that before the turn of the millennium air travel in Asia will account for 40 percent of global travel rising to 50 percent by 2010. The International Air Transport Association also forecast world international scheduled passenger numbers to grow by an average of 7.1 percent annually to 2000, to reach 522 million. Air wars over Asia are hotting up, with some of the world’s biggest airlines engaged in intense competition over Asian skies – potentially the richest and most lucrative air travel market on Planet Earth, notwithstanding the 1997 currency turmoil. This article looks at how competition in the Asia Pacific air travel industry was played out in the 1990s. A glimpse of what is to come can be drawn from the several tough skirmishes seen thus far in the 1990s.

In the present study, wire electro-discharge machining (WEDM) of Inconel 625 (In-625) is performed with the machining parameter such as spark-on time, spark-off time, wire-speed, wire tension and servo voltage. The purpose of this study is to find the most favorable machining parameter setting with respect to WEDM performance such as material removal rate (MRR) and surface roughness (RA).

Taguchi’s L27 orthogonal array has been used to design the experiments with varying machining parameters into three-level four factors. A hybrid multi-optimization technique has been purposed with grey relation analysis and fuzzy inference system integrated with teaching learning-based optimization to achieve optimum machinability (MRR and RA in present case). The obtained result has been compared with two evolutionary optimization tools via a genetic algorithm and simulated annealing.

It has been found that proposed hybrid technique taking minimum computational time, provide better solution and avoid priority weightage calculation by decision-makers. A confirmation test has been performed at single and multi-optimal parameter settings. The decision-makers have been chosen to select any single or multi-parameter setting as per the industry’s demand.

The proposed optimization technique provides better machinability of In-625 using zinc-coated brass wire electrode during WEDM operation.

Although the Singapore model of ethnic integration through its public housing programme is well known, the formula for replicating its success elsewhere remains underexplored. This study aims to identify the criteria for successful transplantation, specifically by identifying the housing tenure types that are most amenable to the implementation of the Singapore model.

Through a comparative study of two common law jurisdictions – Singapore and England – this article highlights the differences in their housing landscapes and how such differences impact upon the adoption of ethnic integration policies through housing. The article also unpacks, through a cross-disciplinary lens, the concepts of public housing and housing tenures, drawing heavily on socio-legal and housing literature.

The authors observe that the implementation of ethnic integration policies is best justified and most easily achieved in leasehold estates that exhibit a strong tenurial relationship with the state retaining a more than notional role. Public housing in Singapore being an exemplar of this model, the implementation of its ethnic integration policy is relatively straightforward. By contrast, the shrinking public housing sector in England means that adoption of a similar policy would have limited reach. Even then, the political–legal environment in England that promotes home ownership is potentially hostile to the adoption of such policy as it may be seen as an infringement of private property right.

The cross-jurisdiction comparison is supplemented by an interdisciplinary analysis that seeks to bridge differences in the categorisation of tenure in housing and law literatures so as to promote cross-disciplinary dialogue.