Structural equation modeling of sustainable manufacturing practices

The purpose of this research study is to study the sustainable manufacturing practices across industrial sectors and to identify the critical factors for its success implementation. In spite of the fact that sustainable manufacturing has been frequently promoted as a means of improving business competitiveness, small empirical evidence exists in the literature validating its positive link with organizational performance. Sustainable manufacturing practices enable the manufacturing organizations to survive in the competitive environment. For this purpose, empirical data are collected to measure the sustainable manufacturing practices prevailing across different industries located in Tamil Nadu, India. Structural equation modeling (SEM) technique is used to build the measurement and structural models. After that, statistical estimates are used to validate the built model. The data analysis enables the acceptance or rejection of the hypothesis that has been stated on the basis of structural model. The results show the correlation between sustainable manufacturing practices and organizational performance among the industries being surveyed.     

Al-decorated carbon nanotube as the molecular hydrogen storage medium

Al-decorated, single-walled carbon nanotube has been investigated for hydrogen storage applications by using Density Functional Theory (DFT) based calculations. Single Al atom-decorated on (8,0) CNT adsorbs upto six H₂ molecules with a binding energy of 0.201 eV/H₂. Uniform decoration of Al atom is considered for hydrogen adsorption. The first Al atom has a binding energy of 1.98 eV on (8,0) CNT and it decreases to 1.33 eV/Al and 0.922 eV/Al respectively, when the number of Al atoms is increased to four and eight. Each Al atom in (8,0) CNT-8Al adsorbs four H₂ molecules, without clustering of Al atoms, and the storage capacity reaches to 6.15 wt%. This gravimetric storage capacity is higher than the revised 2015 target of U.S Department of Energy (DOE). The average adsorption binding energy of H₂ in (8,0) CNT-8(Al+4H₂), i.e. 0.214 eV/H₂, lies between 0.20 and 0.60 eV/H₂ which is required for adsorbing and desorbing H₂ molecules at near ambient conditions. Thus, Al-decorated (8,0) CNT is proposed as a good hydrogen storage medium which could be useful for onboard automobile applications, at near ambient conditions.     

Application of ECQFD for enabling environmentally conscious design and sustainable development in an electric vehicle

Environmental consciousness is regarded as a vital concept for survival in the competitive market scenario. The need for infusing environmental consciousness during early stage of product design is important. This article reports a study which is focused on the application of Environmentally Conscious Quality Function Deployment (ECQFD) to an electric vehicle. ECQFD consists of four phases. ECQFD phases I and II are concerned with the identification important parts of electric vehicle that are vital for improving the environmental consciousness. ECQFD phases III and IV are used to analyze which design changes among the formulated design options of electric vehicle are most effective with regard to environmental improvement. The study results indicate that it could be applied in early product design and development stages for ensuring sustainability.     

Tools and techniques for enabling sustainability through lean initiatives

There has been a paradigm shift in the manufacturing systems. Lean manufacturing is a manufacturing system that is focused on the elimination of wastes thereby facilitating process streamlining and waste reduction. In the recent days, the need for environmental consciousness is very much realized. The environmental waste is regarded as the ninth waste. This article focuses on the exploration of various issues of sustainability using lean initiatives. Also, some of the strategies/techniques that would enable the achievement of sustainability objectives using lean initiatives are presented.     

H2 adsorption in Ni and passivated Ni doped 4 Å single walled carbon nanotube

Adsorption binding energies have been calculated for Nickel-doped single-walled carbon nanotubes (CNTs). Density Functional Theory (DFT) with double numerical polarization (DNP) has been used for finding the total energies of the structures. It is found that the Nickel doped CNTs show fluctuation in the binding energies of hydrogen adsorption which is overcome by passivating the Nickel atom with two hydrogen atoms. The density of states (DOS) and Mullikan atomic charge analysis have been carried to confirm the charge transfer from Ni to the carbon atoms of the CNT. The smallest CNT (diameter ≈ 4 Å) with the chirality of (5,0) has been taken for hydrogen adsorption studies. Geometry optimization shows that Ni atom prefers bridge site rather than the centre of the hexagon. The H₂ binding energies obtained in the present study reveal that desorption would take place above room temperature in Ni doped (5,0) CNTs.     

Thirty-criteria-based agility assessment: a case study in an Indian pump manufacturing organisation

The present market situation has become fragile, so in order to adopt and hence to sustain an organisation, it needs to evaluate itself, so as to identify its current strategic agile position. In today's trend agility exerted by manufacturing, organisation plays an important role. The present work has been conducted to assess the agility of the manufacturing organisation using a scoring approach. This paper presents a 30-criteria agility assessment model which could be utilised to measure agility and to identify the agile characteristics of organisation. Thus, weak factors were identified, and proposals are suggested so as to enhance the agility of the organisation.     

Leanness evaluation using IF–THEN rules

Lean manufacturing is a manufacturing system aimed at waste elimination thereby streamlining the process. Leanness is the performance measure of lean manufacturing. The measurement of leanness necessitates fuzzy logic, due of the existence of impreciseness and vagueness. The calculation of leanness using fuzzy logic manually is a time consuming and highly repetitive job. To overcome this, fuzzy logic-based inference method has been attempted in this research study. A conceptual model consisting of three levels namely enabler, criterion, and attributes has been developed. Then the linguistic variables are assigned and the membership functions are defined. Leanness level has been computed using IF–THEN rules based interface method. This is followed by gap analysis to identify the weaker criteria. Then suitable proposals have been derived to overcome these obstacles towards leanness improvement of the organization.     

Assessment of product sustainability and the associated risk/benefits for an automotive organisation

Incorporating environmental aspects into a product poses a greater challenge to the stakeholders. There are various environmental issues concerned with developing a product and often they are found to be conflicting. There exists a need to examine the environmental risks and benefits associated with any product so that improvements can be made in dealing with the end of life issues of any product. An easy to adopt evaluation model was described which allows this risk/benefit assessment to be made in a sequential manner throughout the life cycle of any product considering environmental characteristics. The major environmental risks/benefits are tabulated and presented graphically for ease of evaluation in order to improve the automotive product. A simple but effective way of sorting out design-oriented issues studied was also explained and suitable alternatives were suggested with the aim of reducing the environmental impact of the automotive product.     

Optimization of friction welding of tube-to-tube plate using an external tool by Taguchi method and genetic algorithm

Numerous advancements have been occurring in the field of materials processing. Friction welding is an important solid-state joining technique. In this research project, friction welding of tube-to-tube plate using an external tool (FWTPET) has been performed, and the process parameters have been prioritized using Taguchi??s L₂₇ orthogonal array. Genetic algorithm (GA) is used to optimize the welding process parameters. The practical significance of applying GA to FWTPET process has been validated by means of computing the deviation between predicted and experimentally obtained welding process parameters.