Anish Sachdeva

Security risk assessment: Applying the concepts of fuzzy logic

Chemical process industries (CPI) handling hazardous chemicals in bulk can be attractive targets for deliberate adversarial actions by terrorists, criminals and disgruntled employees. It is therefore imperative to have comprehensive security risk management programme including effective security risk assessment techniques. In an earlier work, it has been shown that security risk assessment can be done by conducting threat and vulnerability analysis or by developing Security Risk Factor Table (SRFT). HAZOP type vulnerability assessment sheets can be developed that are scenario based. In SRFT model, important security risk bearing factors such as location, ownership, visibility, inventory, etc., have been used. In this paper, the earlier developed SRFT model has been modified using the concepts of fuzzy logic. In the modified SRFT model, two linguistic fuzzy scales (three-point and four-point) are devised based on trapezoidal fuzzy numbers. Human subjectivity of different experts associated with previous SRFT model is tackled by mapping their scores to the newly devised fuzzy scale. Finally, the fuzzy score thus obtained is defuzzyfied to get the results. A test case of a refinery is used to explain the method and compared with the earlier work.

Planning and optimizing the maintenance of paper production systems in a paper plant

Manufacturing and production plants operate physical assets that deteriorate with usage and time, thus, maintenance actions are required to restore the assets back to their original predetermined operational conditions. But since, organizational resources are limited and scarce. The objective of an effective maintenance program is to minimize total cost of inspection and repair, and equipment downtime. In this paper, we describe a new multi-criteria optimization framework for deriving optimal maintenance schedules for preventive maintenance which considers availability, maintenance cost and life cycle costs as the criteria for optimization. The Simulink toolbox of the Matlab has been interfaced with Genetic algorithm for optimization. After getting solution, Stochastic Petri nets has been used to model the system and find out the effect of optimized maintenance schedules on system performance. The application of the proposed framework has been discussed on a practical case of a paper plant.

Selection of logistic service provider using fuzzy PROMETHEE for a cement industry

Purpose – The purpose of this paper is to develop a method to select the best alternative in a multi‐criteria decision making (MCDM) environment when the decision is taken by a group of members in an uncertain environment.Design/methodology/approach – In this paper, Fuzzy Preference Ranking Organization Method for Enrichment Evaluations (Fuzzy PROMETHEE) technique has been used for MCDM problems. The team of decision makers is constituted to integrate their opinion. The analysis is done using Geometrical Analysis for Interactive Aid (GAIA) plane, available in Decision Lab 2000 software, which provides valuable help in understanding the conflicts among criteria.Findings – The selection of best alternative is done on the basis of generally conflicting criteria. Fuzzy PROMETHEE technique has been proposed and the same is demonstrated using Decision Lab 2000 software. This software can be used for as many criteria as possible and also in a fuzzy environment, where the crisp data for criteria comparison are no...

Reliability analysis of pulping system using Petri nets

Purpose – This paper aims to propose a methodology based on Petri nets to evaluate the reliability characteristics of the pulping system of a paper industry in a realistic working environment. The effects of occurrence of failure/course of actions and availability of repair facilities on system performance have been investigated.Design/methodology/approach – Stochastic Reward Nets (SRN), an extension of Petri nets, are applied to model the interactions among the active/standby units of the system and reliability parameters have been evaluated using Monte Carlo simulation.Findings – The methodology adopted in this paper provides a better understanding of the behavior of the system under varying operating conditions. Reliability analysis of a pulping system of a paper industry presented in this paper will help the management in deciding upon the maintenance strategy to be adopted to improve the performance of the system and consequently reduce the operation and maintenance cost.Originality/value – The appli...

Finish Hard Turning of Continuous and Interrupted Surfaces with Cubic Boron Nitride (CBN) and Coated Carbide Tools

In this article, cubic boron nitride (CBN) and coated carbide tools were used for finish turning of hardened steel with continuous and interrupted surfaces. The objective of this work is to investigate the conditions under which carbide tools can give optimal results in terms of both tool wear and surface integrity of the machined surface in comparison to costly CBN tools. The turning performance was evaluated in terms of maximum flank wear of the tools as well as surface integrity issues of the machined surface like white layer formation, microhardness decrease, and surface roughness increase. The results indicated that the longest tool life was achieved with CBN tool, but the accumulated machining time of all the four cutting edges in carbide tool was comparable with that of CBN tool. Significant affect of surface interruptions on tool life of carbide tool was observed, while life of CBN tool was not much affected by surface interruptions. The surface integrity achieved with carbide tools was comparable with that of CBN tools. The surface roughness value observed with both tools was below 1.6 µm. No white layer was observed while turning the interrupted and fully interrupted surfaces with both tools.

Trust among supply chain partners: a review

Purpose – The primary purpose of this paper is to develop a context‐dependent, multi‐perspective and multilevel concept called “trust” among supply chain members (SCM); second, to classify trust; third, to classify available literature and finally, to propose areas for future research. The field related to trust among supply chain partners has historically been collected through studies in micro‐ functional areas. While some effort towards producing a broader organizational perspective has been made, nonetheless, trust in SCM continues to be largely eclectic, with little consensus on its conceptualization and research methodological bases. This paper seeks to clarify aspects of this emerging perspective.Design/methodology/approach – A total of 100 papers/articles were systematically perused and analyzed.Findings – A number of key findings emerged: the field is a relatively “new” one for supply chain management; several disciplines claim ownership of the field; consensus is lacking on the definition of the...

Optimization and Analysis of Shrinkage in Selective Laser Sintered Polyamide Parts

Decreasing shrinkage during selective laser sintering process improves quality and functionality of the product. A model has been purposed to predict the shrinkage in terms of process parameters such as laser power, scan spacing, bed temperature, hatch length, and scan count. Face centered central composite design response surface methodology was employed to develop a model, and the adequacy of the model was verified using analysis of variance. The experiments were conducted on duraform polyamide material by using vanguard HS SLS machine by 3D systems. The effects of the different process parameters on shrinkage were analyzed and optimized.

Optimization and Analysis of Mechanical Properties for Selective Laser Sintered Polyamide Parts

Selective laser sintering (SLS) is one of the widely used rapid prototyping (RP) processes. The main challenge of this process is to choose the correct working parameters to attain the desired shape, size, and strength of different products. Therefore, this article pertains to an experimental study carried out to understand mechanical properties of selective laser sintered polyamide parts. Experiments were established based on face-centered central composite design (CCD) of response surface methodology (RSM). The effect of various process parameters on different properties (i.e., ultimate tensile strength, % elongation, yield strength, and Youngs modulus) was analyzed. Analysis of variance was employed to check the adequacy of the developed models. Furthermore, the optimal combination of these process parameters has been evaluated. Considering ultimate tensile strength, % elongation, yield strength, and Youngs modulus simultaneously, the optimum values of different process parameters have been obtained as: laser power, 32 W; scan spacing, 0.17 mm; bed temp, 178°C; and scan count, 2.

Maintenance criticality analysis using TOPSIS

In this paper, a multi factor decision making approach is presented for prioritizing failures causes for the digester of pulping system of a paper mill as an alternative to traditional approach of failure mode and effect analysis (FMEA). The approach is based on the ‘technique for order preference by similarity to ideal solution’ (TOPSIS). The priority ranking is formulated on the basis of six parameters (failure occurrence, non detection, maintainability, spare parts, economic safety and economic cost). The Shannons entropy concept is used for assigning objective weights to maintenance parameters.

A methodology to determine maintenance criticality using AHP

The aim of this paper is to develop a new maintenance decision strategy by integrating the criticality of various factors related to failure and repair of a component/subsystem as an alternative to traditional approach of Failure Mode and Effect Analysis (FMEA). The methodology presented is based on Analytical Hierarchical Process (AHP) technique which will provide an aid to the maintenance managers/analysts to formulate an efficient and effective priority ranking of the various components/failure modes based on a number of maintenance issues. The principles of the theory and an actual case from a paper industry is undertaken to illustrate the use of the proposed methodology.