Does the Integration of Lean Production and Industry 4.0 in Green Supply Chains Generate a Better Operational Performance?

Purpose – The tightening of environmental measures and policies in various countries around the world is forcing manufacturing companies, particularly those that make up the automotive industry, to improve their production processes, through the implementation of approaches such as lean production and industry 4.0 technologies, to reduce industrial waste. However, the literature indicates that the implementation of lean production and Industry 4.0 does not always lead to an improvement in the level of operational performance. Therefore, this study analyzes the effects of the implementation of lean production practices and Industry 4.0 on a green supply chain and the operational performance of manufacturing companies in the Mexican automotive industry. Methodology/design/approach - A theoretical research framework consisting of six hypotheses was developed and validated by applying PLS-SEM and using a sample of 460 companies from the Mexican automotive industry. Findings - The results show that the level of operational performance of manufacturing companies increases substantially with the implementation of lean production and industry 4.0 practices, as well as a green supply chain. Originality/value - This study contributes to the literature on lean production and Industry 4.0 by providing robust empirical evidence of the positive effects of implementing these approaches on the green supply chain and operational performance of manufacturing companies. Practical implications - Managers of manufacturing companies will be able to use the results of this study to improve their production systems and to demonstrate the effects of these practices on operational performance

Overview of recent TJ-II stellarator results

The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presented. ISSN:0029-5515 ISSN:1741-432

Enabling Materials By Dimensionality: From 0D to 3D Carbon-Based Nanostructures

This chapter is aimed at analysing the influence that dimensional scaling exerts on the electronic, optical, transport and mechanical properties of materials using both experiments and computer simulations. In particular, to climb the “dimensional ladder” from 0D to 3D, we analyse a specific set of all-carbon allotropes, making the best use of the versatility of this element to combine in different bonding schemes, such as sp2 and sp3, resulting in architectures as diverse as fullerenes, nanotubes, graphene, and diamond. Owing to the central role of carbon in future emerging technologies, we will discuss a variety of physical observables to show how novel characteristics emerge by increasing or decreasing the dimensional space in which particles can move, ranging from the charge transport in semiconductor (diamond) and semimetallic (graphite) samples to the stress-strain characteristics of several 2D carbon-based materials, to the gas absorption and selectivity in pillared structures and to the thermal diffusion in foams. In this respect, our analysis uses ab initio, multiscale and Monte Carlo (MC) methods to deal with the complexity of physical phenomena at different scales. In particular, the response of the systems to external electromagnetic fields is described using the effective dielectric model of the plasma losses within a Monte Carlo framework, while pressure fields are dealt with the ab initio simulation of the stress-strain relationships. Moreover, in this chapter we present recent theoretical and experimental investigations aimed at producing graphene and other carbon-based materials using supersonic molecular beam epitaxy on inorganic surfaces, starting from fullerene precursors. We mostly focus on the computational techniques used to model various stages of the process on multiple length and time scales, from the breaking of the fullerene cage upon impact to the rearrangement of atoms on the metal surface used to catalyse graphene formation. The insights obtained by our computational modelling of the impact and of the following chemical-physical processes underlying the materials growth have been successfully used to set up an experimental procedure that ended up in the production of graphene flakes by C60 impact on copper surfaces