This paper presents a new method for the automated design of the conformal cooling system for injection molding technology based on a discrete multidimensional model of the plastic part. The algorithm surpasses the current state of the art since it uses as input variables firstly the discrete map of temperatures of the melt plastic flow at the end of the filling phase, and secondly a set of geometrical parameters extracted from the discrete mesh together with technological and functional requirements of cooling in injection molds. In the first phase, the algorithm groups and classifies the discrete temperature of the nodes at the end of the filling phase in geometrical areas called temperature clusters. The topological and rheological information of the clusters along with the geometrical and manufacturing information of the surface mesh remains stored in a multidimensional discrete model of the plastic part. Taking advantage of using genetic evolutionary algorithms and by applying a physical model linked to the cluster specifications the proposed algorithm automatically designs and dimensions all the parameters required for the conformal cooling system. The method presented improves on any conventional cooling system design model since the cooling times obtained are analogous to the cooling times of analytical models, including boundary conditions and ideal solutions not exceeding 5% of relative error in the cases analyzed. The final quality of the plastic parts after the cooling phase meets the minimum criteria and requirements established by the injection industry. As an additional advantage the proposed algorithm allows the validation and dimensioning of the injection mold cooling system automatically, without requiring experienced mold designers with extensive skills in manual computing.

This paper presents a new procedure for the building information modeling (BIM) characterization of structural topologies manufactured with plastic materials and fused deposition modeling (FDM) additive technology. The procedure presented here transforms the architectural geometry into an expanded three-dimensional model, capable of directly linking the topology of the plastic structure with the technological, functional and economic requirements for working in advanced construction 4.0 environments. The model incorporates a new algorithm whose objective is to recognize the topological surface of the plastic structural part obtaining in a fully automated way the FDM manufacturing time as well as the manufacturing cost. The new algorithm starts from the voxelized geometrical surface of the architectural model, calculating the manufacturing time from the full geometric path traveled by the extruder in a voxel, the extruder’s speed, the print pattern and the layer height. In this way it is possible to obtain a complete digital model capable of managing and analyzing the plastic architectural object in an advanced BIM 4.0 environment. The model presented in this paper was applied to two architectural structures designed for a real urban environment. The final structural geometries have been obtained through topological processes in order to reduce the raw plastic manufacturing material and to improve the plastic structure strength. The architectural elements have been validated structurally by the means of numerical simulations, following the scenario of loads and boundary conditions required for the real project. The displacement maps point to a maximum value of 0.5 mm according to the project requirements. The Von Mises stress fields indicate maximum values of 0.423 and 0.650 MPa, not exceeding in any case the tensile yield strength of the thermoplastic material.

One of the polymeric materials used in the most common 3D printers is poly(ethylene terephthalate) glycol (PETG). It represents, in world terms, around 2.3% of polymeric raw material used in additive manufacturing. However, after processing this material, its properties change irreversibly. A significant amount of waste is produced around the world, and its disposal is usually destined for landfill or incineration, which can generate an important issue due to the high environmental risks. Polymer waste from 3D printing, hereinafter 3DPPW, has a relatively high calorific value and adequate characteristics to be valued in thermochemical processes. Gasification emerges as an innovative and alternative solution for recovering energy from 3DPPW, mixed with residues of lignocellulosic origin, and presents some environmental advantages compared to other types of thermochemical treatments, since the gasification process releases smaller amounts of NOx into the atmosphere, SOx, and CO₂. In the case of the study, co-gasification of olive pomace (OLB) was carried out with small additions of 3DPPW (10% and 20%) at different temperatures. Comparing the different gasifications (100% OLB, 90% OLB + 10% 3DPPW, 80% OLB + 20% 3DPPW), the best results for the synthesis gas were obtained for the mixture of 10% 3DPPW and 90% olive pomace (OLB), having a lower calorific value of 6.16 MJ/m³, synthesis gas yield of 3.19%, and cold gas efficiency of 87.85% for a gasification temperature of 750 °C. In addition, the results demonstrate that the addition of 3DPPW improved the quality of syngas, especially between temperatures of 750 and 850 °C. Including polymeric 3D printing materials in the context of the circular economy and extending their life cycle helps to improve the efficiency of subsequent industrial processes, reducing process costs in general, thanks to the new industrial value acquired by the generated by-products.

The global production of polymer materials has exploded in the last few decades. Their mechanical properties, erosion and corrosion resistance, good performance as insulation materials, and their ease and flexibility of manufacturing have made polymers one of the most widely used materials in the industry and in daily life. Several institutions and governments are beginning to raise serious environmental and ecological concerns with international impact soon, due to the increasing level of polymer production, which does not seem to be slowing down. It is necessary for the scientific community to make efforts in the development and evaluation of new methodologies to enable the inclusion of these types of materials in the circular economy of various production sectors. This is important in order to reduce the ecological impact caused by the current global production level of polymers. One of the most used methods for the recovery of polymeric materials is energy valorization through thermochemical processes. An example of this is thermal gasification using fuels composed of biomass and a mixture of polymeric waste from electrical and electronic equipment (WEEE). Through this thermochemical process, high-energy value synthesis gas, with a high concentration of hydrogen, is obtained on one hand, while waste products in the form of chars, ashes and slag are generated on the other hand. This manuscript presents a detailed study methodology that begins with chemical analysis of the raw material and includes subsequent analysis of mechanical results for the revaluation of these residual inert by-products, using them as partial substitutes in cement clinker to produce building mortars. This described methodology influences directly in the LCC (Life Cycle Costing) of final designed products in plastic and extend material life cycle Plastic materials are here to stay, so the study and optimization of polymer waste recovery processes are vital in achieving the Sustainable Development Goals (SDGs) set by the European Union in terms of efficiency and sustainability. It is also the only possible way to create an environmentally sustainable future world for future generations. After applying the described methodology, the mechanical test results show that the modified mortars exhibit established behaviour during the hardening time and similar strength growth compared to commercial mortars. The maximum mechanical strengths achieved, including compressive and flexural strength, make modified mortars a viable choice for several applications in the civil engineering sector.