The environmental consciousness of customers and the emergence of stricter environmental regulations has pushed industries to think about environmental management by means of reverse logistics (RL) implementation. In order to implement RL systems, a careful analysis of barriers that hinder the reverse flow must be taken. However, most existing research on the barriers for RL implementation is focused on developed countries. Among the most important emerging economies, Brazil, the largest Latin America economy, faces challenges such as a deficient logistics infrastructure and the recently enacted National Policy on solid waste. To bridge this gap, this paper identifies and evaluates the barriers for RL in the Brazilian context. An eleven-step research methodology is proposed. First, literature was thoroughly reviewed. fuzzy Delphi method (FDM) was used to obtain the critical list of barriers by experts and industrial managers’ opinions. Then, analytic hierarchy process (AHP) questionnaires were answered by electrical–electronic equipment (EEE) industry sector experts in order to obtain the priority ranking of barriers. This paper contributes with a compilation of the RL barriers from a systematic literature review process, a list of most common RL barriers accepted by Brazilian organizations, and a priority ranking of RL barriers for the electrical-electronic industry sector in Brazil. The “Economic related issues” category of barriers seems to be the first priority. The financial burden of tax and the uncertainty related to economic issues appear to be major obstacles for RL implementation.

Identification and analysis of reverse logistics barriers using fuzzy Delphi method and AHP

Drastic improvement in mechanical properties and weldability of 316L stainless steel weld joints by using electromagnetic vibration during GTAW process

An iterated greedy algorithm with optimization of partial solutions for the makespan permutation flowshop problem

A comparison of residual stresses in multi pass narrow gap laser welds and gas-tungsten arc welds in AISI 316L stainless steel

Numerical simulation and experiment analysis of angular distortion and residual stress in hybrid laser-magnetic welding

In laser welding, typical welding penetration depths are in the order of 1–2 mm/kW laser power. The multipass laser welding technique, based on the narrow-gap approach, is an emerging welding technology that can be applied to thick-section welds by using relatively low laser power, but the process is more complicated since it is necessary to introduce filler wire to narrow-gap weld configurations. The aim of this work was to understand significant process parameters and their interactions in order to control the weld quality in ultra-narrow-gap (1.5 mm gap width) laser welding of AISI grade 316L stainless steel. A 1-kW IPG single-mode fiber laser was used for welding plates that were 5 to 20 mm in thickness using the multiple-pass narrow-gap approach. Design of experiments and statistical modelling techniques were employed to understand and optimise the processing parameters. The effects of laser power, wire feed rate, and welding speed on the weld homogeneity, integrity, bead shape, gap bridgability and surface oxidation were studied. The results were evaluated under different optimising constraints. The results show that the models developed in this work can effectively predict the responses within the factors domain.

Understanding the process parameter interactions in multiple-pass ultra-narrow-gap laser welding of thick-section stainless steels

Measurement and modelling of the residual stresses in autogenous and narrow gap laser welded AISI grade 316L stainless steel plates

Laser welding of metals typically has a weld penetration of 1-2 mm/kW laser power. Therefore laser welding of thick section materials would require very high power lasers. In this paper we report an investigation into multi-pass laser welding of 316L stainless steel sheets of 5-10 mm thickness, based on narrow gap (1.5 mm) approach using a 1 kW single mode fibre laser. A filler wire of 316L with a 0.8 mm diameter was used in the welding process. The integrity of the weld, microstructure and heat affected zones, as well as weld bead geometry, and mechanical properties were examined. The effect of laser welding parameters on these properties is discussed.

A. S. Elmesalamy

Papers

Understanding the process parameter interactions in multiple-pass ultra-narrow-gap laser welding of thick-section stainless steels

Measurement and modelling of the residual stresses in autogenous and narrow gap laser welded AISI grade 316L stainless steel plates

Narrow gap laser welding of thick section stainless steel