Abstract
Resource efficiency is a crucial step for manufacturing companies to improve their operations performance and to reduce waste generation. However, there is no guarantee of a zero waste scenario and companies need to look for new strategies to complement their resource efficiency vision. Therefore, it is important to enroll in an industrial symbiosis strategy as a means to maximize industrial value capturing through the exchange of resources (waste, energy, water and by-products) between different processes and companies. Within this, it is crucial to quantify and characterize the waste, e.g. to have clear understanding of the potential industrial symbiosis hot spots among the processes. For such characterization, it is proposed to use an innovative process efficiency assessment approach. This empowers a clear understanding and quantification of efficiency that identifies industrial symbiosis hot spots (donors) in low efficiency process steps, and enables a plausible definition of potential cold spots (receivers), in order to promote the symbiotic exchanges. (C) 2018 The Authors. Published by Elsevier B.V.

Abstract
Design-for-X (DfX) approaches are of great importance to support sustainable development of new products, since the goal of DfX practices is to improve life cycle cost, life cycle environmental performance, increase design flexibility, manufacturing efficiency, etc. Therefore DfX supports a better decision-making process whenever a new complex product is being developed. In this work the new Lean Design-for-X (LDfX) approach is presented embracing the principles of Lean Product Development and Modular Design, for a systematic applicability by design engineers and product managers, assessing the effectiveness and efficiency of a given product design. An LDfX index metric, ranging between 0-100%, and original scorecard were created for consistent decision support for the comparison of different design concepts or products, integrating different "X" domains. The approach was applied in a real design study of a machine tool (press-brake), integrating Ecodesign principles, Design for Structural Optimization and Modular Design. (C) 2018 The Authors. Published by Elsevier B.V.

Abstract
The MAESTRI Total Efficient Framework (MTEF) is a recent holistic concept that congregates four complementary dimensions: Efficiency Framework; IoT Platform; Management System and Industrial Symbiosis. MTEF promotes the development of strategies for continuous performance improvement towards a more sustainable manufacturing. The Efficiency Framework supports the integrated assessment of operations efficiency and eco-efficiency, being measured by a new concept: Total Efficiency Index (TEI). The simultaneous assessment of the environmental, economic and efficiency performance of complex production systems is only possible with a digitalized production system, which is aligned with Industry 4.0 paradigm. Thus, with TEI original dashboards and graphical diagram, both static and dynamic assessments of efficiency vs. eco-efficiency can be analyzed. This paper details the fundaments of the Efficiency Framework and TEI, and presents an application case study from the metalworking sector, where the achieved results are discussed for the new concept validation. (C) 2018 The Authors. Published by Elsevier B.V.

Abstract
Similitude theory is a branch of engineering science concerned with establishing the necessary and sufficient conditions of similarity among phenomena, and has been applied to different fields such as structural engineering, vibration and impact problems. Testing of subscale models is still nowadays a valuable design tool, helping engineers to accurately predict the behavior of oversized prototypes through scaling laws applied to the obtained experimental results. However, several limitations and difficulties still persist when applying the similitude theory through the current methodologies to complex structures. This manuscript presents an original modular approach. The objective is to improve how the similitude theory is applied through the governing equations, overcoming part of the identified constraints. The major achievement is that, with the new approach, the similitude theory can be applied to complex structures through differential equations of its simple substructures, even if the governing equations for the whole structure are not available. A stiffened plate is selected to demonstrate the use of the modular approach and the accuracy of the scaled model testing. To that end, the modular approach has to be firstly applied to the generalized simple plate and beam. Even though the simplifying assumptions are minimized in the substructure governing equations, the modular, approach is able to avoid the expected increase in the mathematical effort and complexity of the process of applying the similitude theory. In a second step, a relation is established between the scaling relationships derived for each simple structural element of the complex prototype.

Abstract
The irregular strip packing problem consists of cutting a set of convex and non-convex two-dimensional polygonal pieces from a board with a fixed height and infinite length. Owing to the importance of this problem, a large number of mathematical models and solution methods have been proposed. However, only few papers consider that the pieces can be rotated at any angle in order to reduce the board length used. Furthermore, the solution methods proposed in the literature are mostly heuristic. This paper proposes a novel mixed integer quadratically-constrained programming model for the irregular strip packing problem considering continuous rotations for the pieces. In the model, the pieces are allocated on the board using a reference point and its allocation is given by the translation and rotation of the pieces. To reduce the number of symmetric solutions for the model, sets of symmetry-breaking constraints are proposed. Computational experiments were performed on the model with and without symmetry-breaking constraints, showing that symmetry elimination improves the quality of solutions found by the solution methods. Tests were performed with instances from the literature. For two instances, it was possible to compare the solutions with a previous model from the literature and show that the proposed model is able to obtain numerically accurate solutions in competitive computational times.

Abstract
Portuguese footwear industry has improved dramatically to become one of the main world players. This work is part of a project in cooperation with a large footwear company, operating a new automated assembly equipment, integrating various lines. Balancing such lines implies going from an almost manual preparation executed by experienced operators, to a planning supported by optimisation systems. These complex mixed-model lines have distinctive characteristics, which make balancing a unique problem. The paper proposes the ASBsm – Assembly System Balancing Solution Method, a new method that integrates a constructive heuristic and an improvement heuristic, which takes inspiration from Tabu Search. The solutions obtained, based on real instances, are quite encouraging when compared with other effected factory solutions. Consequently, the balances obtained by ASBsm are now being implemented and articulated with sequencing methods. © IFIP International Federation for Information Processing 2017.