A framework for the integration of Green and Lean Six Sigma for superior sustainability performance

Evidence suggests that Lean, Six Sigma and Green approaches make a positive contribution to the economic, social and environmental (i.e. sustainability) performance of organisations. However, evidence also suggests that organisations have found their integration and implementation challenging. The purpose of this research is therefore to present a framework that methodically guides companies through a five stages and sixteen steps process to effectively integrate and implement the Green, Lean and Six Sigma approaches to improve their sustainability performance. To achieve this, a critical review of the existing literature in the subject area was conducted to build a research gap, and subsequently develop the methodological framework proposed. The paper presents the results from the application of the proposed framework in four organisations with different sizes and operating in a diverse range of industries. The results showed that the integration of Lean Six Sigma and Green helped the organisations to averagely reduce their resources consumption from 20 to 40% and minimise the cost of energy and mass streams by 7–12%. The application of the framework should be gradual, the companies should assess their weaknesses and strengths, set priorities, and identify goals for successful implementation. This paper is one of the very first researches that presents a framework to integrate Green and Lean Six Sigma at a factory level, and hence offers the potential to be expanded to multiple factories or even supply chains.     

Equilibrium on line method (ELM) for imposition of Neumann boundary conditions in the finite point method (FPM)

Equilibrium on line method (ELM) for imposition of Neumann boundary conditions in the finite point method (FPM) is presented. In contrary to weak‐form‐based methods, strong‐form‐based methods such as the FPM are often unstable and less accurate, especially for problems governed by partial differential equations with Neumann (derivative) boundary conditions. In this paper, a truly meshless approach for imposition of Neumann boundary conditions in the FPM is proposed and adopted for 2D elasticity analyses. In the proposed method, equilibrium on lines on the Neumann boundary conditions is satisfied as Neumann boundary condition equations. Numerical studies show that this method for imposition of Neumann boundary is simple to implement and computationally efficient and also leads to more stable and accurate results. Copyright © 2006 John Wiley & Sons, Ltd.     

An AHP-based multi-criteria model for assessment of the social sustainability of technology management process: A case study in banking industry

The abrupt development of technology has confronted different industries' managers with crucial decision points. The scope of their decisions' impact goes beyond their companies' borders. Sustainable assessment of technology investigates the economic, environmental, and social effects of technologies on firms and their environment. Nonetheless, the technology management process includes different steps (such as technology acquisition and exploitation) which need a comprehensive decision-making tool toward sustainable development targets. This paper aims to propose an integrated decision-making model to investigate the social sustainability of the technology management process. Considering three main steps of the technology management process (technology selection, technology acquisition, and technology exploitation), we constructed our model utilizing the Analytic Hierarchy Process (AHP) as one of the most popular decision-making tools. In order to evaluate the efficiency of the model, we implemented it for E-banking technologies in one of the oldest banks of Iran (Iran's AgriBank). The results indicated that internet banking, internal R&D, and internal exploitation are the best decision alternatives among the technology management process from the social sustainability perspective. The results were validated by calculating the Consistency Rate (CR) and performing scenario-based sensitivity analysis.     

Modelling and simulation of the electric slag remelting guide vane casting (ESRC) process and its application

Modelling and experiment work is carried out for a large stainless steel casting with variable cross-section and a curved surface which is produced by the electric slag remelting casting process. The casting is part of a hydraulic runner generator at a power station of a big river.

Mathematical models of the heat transfer and melted rate from an expendable metallic electrode were established. The melted rate is related to some important parameters, such as electric current and voltage, temperature and the flow rate of the cooling water in a crystallizer. Electrode melting, the moving pattern of the melted pool and the slag pool and the melt solidification in the metal pool were simulated.

In order to make the enmeshment of the variable curved surface of the casting, a co-operation method of extended constructive solid geometry (CSG) from 9 to 21 uniform geometry with B-Spline surface functions is developed. By this method the guide vane casting is enmeshed. The boundary condition between the steel casting and the crystallizer cooled by water was measured.

Based on the above new content the solidification simulation software ESRC3D is developed. Using it to simulate the whole process of ESRC with different parameters, instead of exploring the technological parameters of casting production by the trail-and-error method, the optimized parameters from the simulation for production of the large stainless steel castings with variable cross-section and a curved surface, such as the guide vane castings, have been used to produce them. Economic benefit and good quality of castings are obtained. Guide vane castings are widely applied to the hydraulic runner generator at numerous river power stations.     

Estimating the regional economic impacts of retiring agricultural land: methodology and an application in California

This report is of a study to assess the efficiency and sustainability impacts of a seed-based technology for pigeonpea in semi-arid central India. The problem of integrating environmental assessment with economic and social impact assessment arises from an artificial separation of the social and natural sciences, and the ‘disciplinization’ of the social sciences. Thus sustainability must be defined in a way that pre-empts the need to integrate results obtained from different approaches. Sustainability assessment then is a dynamic not a static framework. It involves changes in labor requirements, in soil and agro-climatic conditions, and in notions and perceptions of efficiency and profitability with differential social and economic impacts. This approach requires a methodology that uses a combination of techniques — survey research, case study, and rapid/participatory rural appraisals — with the flexibility of adjustment and adaptation during the course of research.     

Optimization of the process variables of roller compaction,on the basis of granules characteristics (flow,mechanical strength,and disintegration behavior): an application of SeDeM-ODT expert system

The objective of the study was application of SeDeM-ODT expert system for optimization of process variables for roller compaction and for the preparation of granules with better flow, compressibility, and disintegration behavior. In the present study, granules were prepared at pre-determined (on the basis of factorial design) process variables and characterized using SeDeM-ODT expert system. Compatibility of ribavirin with excipients (microcrystalline cellulose, tablettose-80, cross carmellose sodium, and magnesium stearate) was evaluated by binary mixture approach, using FTIR. According to the SeDeM-ODT expert system, granules were characterized for various parameters related to flow, compressibility and disintegration behavior and Index of Good Compressibility and Buccodispersibility (IGCB) was calculated. The process variables resulting in highest IGCB value were considered as optimum. Ribavirin was found compatible with all the excipients used in the study and characteristics peaks were present in FTIR spectra after subjecting to stress conditions (75% relative humidity at 45?±?5?°C) for 30?days. Both Ribavirin powder and Ribavirin containing powder blend had poor flow and compressibility while disintegration behavior was good due to higher water solubility. Screw speed of 35?rpm and roller speed at 12?rpm resulted in granules with acceptable characteristics. The IGCB value (5.63) of the granules was highest of all, indicating its better characteristics. SeDeM-ODT expert system presents a more practical picture of the granules and also predicts the mechanical strength and disintegration behavior of the tablets prepared from the granules. By proper optimization of screw and roller speed, efficiency of the process can be improved.     

Detection of interferences in an additive manufacturing process: an experimental study integrating methods of feature selection and machine learning

Additive manufacturing becomes a more and more important technology for production, mainly driven by the ability to realise extremely complex structures using multiple materials but without assembly or excessive waste. Nevertheless, like any high-precision technology additive manufacturing responds to interferences during the manufacturing process. These interferences – like vibrations – might lead to deviations in product quality, becoming manifest for instance in a reduced lifetime of a product or application issues. This study targets the issue of detecting such interferences during a manufacturing process in an exemplary experimental setup. Collection of data using current sensor technology directly on a 3D-printer enables a quantitative detection of interferences. The evaluation provides insights into the effectiveness of the realised application-oriented setup, the effort required for equipping a manufacturing system with sensors, and the effort for acquisition and processing the data. These insights are of practical utility for organisations dealing with additive manufacturing: the chosen approach for detecting interferences shows promising results, reaching interference detection rates of up to 100% depending on the applied data processing configuration.     

Prediction of fatigue life with interspersed mode-I and mixed-mode (I and II) overloads by an exponential model: Extensions and improvements

The current work is an extension of the authors’ earlier work and presents a life prediction methodology under interspersed mode-I and mixed-mode (I and II) overloads. The important controlling parameter in the model is ‘specific growth rate’ (m). It depends on two crack driving forces i.e. stress intensity factor range and maximum stress intensity factor as well as material parameters i.e. fracture toughness, Young’s modulus, and yield stress. The dependence of ‘m’ on these parameters is correlated through a dimensionless parameter ‘l’. It is observed that the present model predicts the end life of post-overload period well in case of 7020 T7 and 2024 T3 Al-alloys.     

Bio-composites of kenaf fibers in polylactide: Role of improved interfacial adhesion in the carding process

Bio-composites comprised of kenaf fiber reinforced polylactide are fabricated by carding followed by treatment with a 3-glycidoxypropyl trimethoxy silane and hot-pressing. The effects of the silane coupling agent on composite properties was highly beneficial leading to increased moduli and heat deflection temperatures as well as reduced water swelling. Swelling is found to increase with increasing kenaf loading levels but to decrease with increasing coupling agent concentrations. Mechanical properties of the bio-composites at tempertaures above the glass transition are vastly improved in comparison to the base PLA polymer. As little as 10 wt.% kenaf fiber in PLA provides a heat distortion temperature in excess of 140 °C when combined with the coupling agent. The thermal stability towards degradation is slightly decreased relative to the base PLA and the ash content is increased. Thermal properties such as the glass transition, melting temperature, and percent crystallinity of the matrix PLA are largely unaffected by incorporation into the composites. Evidence of successful reaction of the silane with the kenaf fibers is provided by FTIR and implied by decreased swelling in water. A prototypical automotive headliner is fabricated as a means of demonstrating the viability of the present bio-composites in real manufacturing processes.     

Simulation of the cabling process for Rutherford cables: An advanced finite element model

In all existing large particle accelerators (Tevatron, HERA, RHIC, LHC) the main superconducting magnets are based on Rutherford cables, which are characterized by having: strands fully transposed with respect to the magnetic field, a significant compaction that assures a large engineering critical current density and a geometry that allows efficient winding of the coils. The Nb₃Sn magnets developed in the framework of the HL-LHC project for improving the luminosity of the Large Hadron Collider (LHC) are also based on Rutherford cables. Due to the characteristics of Nb₃Sn wires, the cabling process has become a crucial step in the magnet manufacturing. During cabling the wires experience large plastic deformations that strongly modify the geometrical dimensions of the sub-elements constituting the superconducting strand. These deformations are particularly severe on the cable edges and can result in a significant reduction of the cable critical current as well as of the Residual Resistivity Ratio (RRR) of the stabilizing copper. In order to understand the main parameters that rule the cabling process and their impact on the cable performance, CERN has developed a 3D Finite Element (FE) model based on the LS-Dyna® software that simulates the whole cabling process. In the paper the model is presented together with a comparison between experimental and numerical results for a copper cable produced at CERN.     

Characterization of 3C-SiC micro-pillars on Si(100) substrate grown by vapor-liquid-solid process

Cubic silicon carbide (3C-SiC) micro-pillars were fabricated on Si (100) substrate by vapor-liquid-solid (VLS) process. The microstructure and residual stress of the micro-pillars were investigated by electron microscopy and micro-Raman spectroscopy, respectively. The selected area diffraction pattern of the SiC micro-pillar indicated that the micro-pillar was 3C-SiC single crystal. The residual stress of about 0.3 GPa in the micro-pillar calculated from Raman spectrum indicated that the VLS grown 3C-SiC micro-pillars had good crystalline quality.     

辐射降解法制备低聚水溶性壳聚糖之二:批量制备工艺研究

对不同生产厂家的食品级大分子壳聚糖原料进行了对比分析,确定了原料的质量要求.进行了批量制备研究,确定了生产流程和生产工艺条件,建立了一种制备低聚水溶性壳聚糖的新方法.     

A supplier selection model: a comparison of fuzzy logic and the analytic hierarchy process

This paper aims to compare two tools for decision makers that intend to support the decision of the selection of the appropriate supplier. Suppliers are crucial to both the efficiency and effectiveness of the performance of companies. A critical success factor of these companies is the selection of the appropriate supplier. A methodology is proposed to optimise the evaluation process based on different criteria. The proposed approach extends the one proposed by Ordoobadi (2009 Ordoobadi, SM. 2009. Development of a supplier selection model using fuzzy logic. Supply Chain Management: An International Journal, 14(4): 314–327. [Crossref], [Web of Science ®] , [Google Scholar], Development of a supplier selection model using fuzzy logic. Supply Chain Management: An International Journal, 14 (4), 314–327) who proposed the application of fuzzy logic (FL) where we use the same example case study in order to compare the analytic hierarch process (AHP) with FL. In this paper we demonstrate how we can achieve the same objective of expressing human assessments in the form of linguistic expressions by using AHP. Moreover, we demonstrate the capability to run a sensitivity analysis which helps to understand the causal relationships among the different factors. We demonstrate how this capability can help us to explain and predict the different relationships among criteria and alternatives. Moreover, we provide a measure that is able to capture the consistency of the decision maker's preferences. In our approach we provide a single unit of scale that is not only capable of ranking suppliers but also provides an understanding of the difference in scale between different suppliers which can then help to allocate resources accordingly. These facilities are not offered by Ordoobadi (2009 Ordoobadi, SM. 2009. Development of a supplier selection model using fuzzy logic. Supply Chain Management: An International Journal, 14(4): 314–327. [Crossref], [Web of Science ®] , [Google Scholar]). The proposed approach here can help companies to identify the best supplier in changing environments. The paper describes a decision model that incorporates a decision maker's subjective assessments and applies a multiple criteria decision making technique to manipulate and quantify these assessments. Unlike many similar studies, two techniques have been performed on the same case study in order to improve our understanding of the differences in the proposed techniques.     

Design resilience in the fuzzy front end (FFE) context: an empirical examination

This study provides a detailed understanding of the flexibilities that affect performance of innovation projects in the fuzzy front end (FFE) stage. We use the ambidextrous theory approach along with theories on flexibility to propose key drivers of design resilience in innovation projects. A set of six in-depth case studies across a variety of contextual settings is used to investigate important sources of flexibilities that contribute to design resilience. The effects of different design flexibility on the firms’ design resilience are examined. Specifically, an in-depth examination of ‘within case’ trends suggested key design flexibilities to be further examined in the ‘across case’ analyses. Our findings provide valuable insights about the enabling design flexibilities and contextual effects of design resilience in the FFE stage of innovation projects. Based on the findings from the case studies, four sources of design flexibility emerged that vary in terms of their influence on design resilience: (1) iterative learning, (2) modularity, (3) engineering change management and (4) design reuse. Patterns from the ‘across case’ analyses were then used to isolate specific types of design flexibilities that are important for design resilience and organisational resilience. We also provide categorisation of these drivers of design resilience in the context of passive flexibility and active flexibility practices. One of the major contributions of the study is that it provides a detailed categorisation of design resilience in relation to organisational resilience.     

Optimisation of the process control in a semiconductor company: model and case study of defectivity sampling

This article studies the skip, under some assumptions, of process control operations. The case of one tool, one enhanced buffer and one metrology tool of a monotonic parameter is analysed. This article presents circumstances in which control plan can be optimised due to the buffer's behaviour. After discussing the industrial issue of defectivity, this article presents a literature review followed by the model and steps towards industrial development. Then demonstrator, which is applied at a case study of defectivity sampling, is presented. A test of over a 300-mm wafer fabrication data set shows serious improvements – around 35% of defectivity controls have been skipped compared to the static sampling plan.     

Controversies in an information technology startup: A critical actor-network analysis of the entrepreneurial process

This article critically investigates the controversies involved in the entrepreneurial process of an IT venture using the Actor-Network Theory (ANT). While ANT and other processual approaches have been used to assess entrepreneurship, little emphasis has been placed on addressing the controversies involved in the entrepreneurial process. To overcome this bias, we used the Cartography of Controversies (CC), an ANT's applied method, to highlight the impacts of conflictual relationships on the organizing process of an IT venture. We based our analysis on a pluralistic corpus of primary data, including interviews, focus groups, field journals, and other documents. We found five main critical issues related to the entrepreneurial process, being them: sociodemographic biases, reproduction of economic and cultural inequalities, conflicts among organizational elites, disputes between owners and workers, and overdependence of startups on larger technological firms. In line with the ‘ANT and After’ literature, we demonstrated how the critical use of ANT sociological approach avoids excessively aggregated categories often present on other critical studies. Finally, we conclude that the critical use of ANT can contribute to more sophisticated and well-built forms of criticism, orienting the research empirically and considering the critical capacities of the actants themselves.     

Scrap value stream mapping (S-VSM): a new approach to improve the supply scrap management process

In this work, an innovative methodology to improve the Supply Scrap Management Process (SSMP), based on Value Stream Mapping (VSM), is presented. VSM is one of the best tools to map a process and eliminate its critical issues, that produces good results if applied to production processes, but can be ineffective for management processes as the SSMP. Therefore, the main objective of this work is to overcome this limitation. The proposed approach taking the name Scrap Value Stream Mapping (S-VSM) and integrates concepts from VSM and other Lean Production (LP) and World Class Manufacturing tools. It is structured in five steps. The definition of the process borders and the identification of categories of loss through the first four steps of Cost Deployment is the first step. Then, the SSMP is subdivided in its Accounting and Physical Streams and the current state is drawn. Next, wastes and critical issues are analysed and their root causes are determined using some of LP tools. In step four, improvements are proposed and the future state is drawn. Furthermore, potential savings, in terms of €, are estimated. In the last step, a methodology to monitor the effects of implemented improvements is defined. A case study taken from the application of the S-VSM within automotive company is presented.     

Encapsulation of titanium (IV) silsesquioxane into the NH4USY zeolite: Preparation, characterization and application

This work describes the encapsulation of titanium (IV) silsesquioxane into the supercavities of NH₄USY ultra stabilized zeolite, after chemical treatment. The modified zeolite was characterized by Fourier transform infrared spectra, Nuclear magnetic resonance, scanning electronic microscopy, X-ray diffraction and thermogravity. This encapsulated titanium (IV) silsesquioxane can adsorb Azure A chloride after treatment with H₃PO₄, without modifier leaching problems. In an electrochemical study, the cyclic voltammograms of the graphite paste modified electrode, shows two redox couples with formal potential (E⁰′) −0.1 V and 0.21 V to I and II redox couples respectively (v=700 mV s−1; Britton Robinson buffer (B-R) solution, pH 3) versus SCE ascribed to a monomer and dimmer of azure. This paper shows the use of ultra stabilized zeolite in the electrochemical field as host for molecules with nanometric dimensions.     

Phase I process monitoring: The case of the balanced one-way random effects model

Phase I is crucial for the success of the overall statistical process control (SPC) and monitoring regime. Shewhart-type charts are recommended in this phase because of their broader shift detection ability. In this paper, a Phase I Shewhart-type $\overline{X}$ chart is considered for the balanced random effects (also called a variance components) model. The proposed methodology takes proper account of the effects of parameter estimation and uses the false alarm probability (FAP) metric to design the chart. In the sequel, the corrected (adjusted) charting constants are calculated and tabulated. The constant can be found, on demand, from an accompanying R package. Motivations and illustrations with some real data are provided. Performance of the chart is examined in terms of in-control robustness and detection of nonhomogeneity (out-of-control). The proposed chart is shown to be easily adaptable to more general models, with more variance components and nested factors, and can accommodate various estimators of variance. Thus, it enables a broader Phase I process monitoring strategy, under normality, which can be applied within the ANOVA framework applicable for many DOE models. A summary and some recommendations are provided.     

Independence of thinned processes characterizes the Poisson process: An elementary proof and a statistical application

Let N, N ₁ and N ₂ be point processes such that N ₁ is obtained from N by homogeneous independent thinning and N ₂=N−N ₁. We give a new elementary proof that N ₁ and N ₂ are independent if and only if N is a Poisson point process. We also present an application of this result to test if a homogeneous point process is a Poisson point process.