Papers by Keyword: Sustainability

Abstract: Aluminum components production is associated with significant greenhouse gas emissions due to both raw material extraction and energy-intensive manufacturing processes. In particular, the melting phase required high thermal energy and conventional energy sources (e.g. fossil fuels, national grids...) can result in relevant environmental impacts. This study evaluates the environmental sustainability of four different energy supply systems for aluminum die casting through a comparative Life Cycle Assessment (LCA). Four scenarios were analyzed: natural gas, national grid electricity, photovoltaic (PV) electricity with battery storage, and PV-powered hydrogen production with metal-hydride storage. A cradle-to-gate approach was adopted, including energy production, storage, raw materials extraction, tool manufacturing, casting operations and finishing. The environmental impacts were modelled using SimaPro, and Global Warming Potential (GWP) was calculated according to the Intergovernmental Panel on Climate Change (IPCC) methodology. The results show that renewable-based solutions represent the most sustainable alternatives, with impact reductions up to 62% compared with traditional approaches. PV electricity with battery storage achieves the lowest unitary impacts (0.15 kg CO₂ eq/kWh). Hydrogen produced from PV electricity also provides significant reductions relative to natural gas and grid electricity and offers high operational flexibility. The metal-hydride storage system shows slightly lower impacts than battery storage, due to its long service life and minimal hydrogen losses. These results highlight the potential of renewable energy and green hydrogen as alternative energy carriers for industrial production.

Abstract: The growing demand for high-performance, sustainable micro-moulded components requires integrated approaches to material and process selection. The study presents a Life Cycle Engineering (LCE) framework for the integrated selection of materials and manufacturing technologies for micro-injection molds, combining Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and multi-criteria decision models. The methodology implements multicriteria cost impact maps and ternary LCA–LCC–technical performance model, allowing for result normalization and sensitivity analysis with respect to criterion weighting. The framework is applied to molds fabricated from steel, aluminium alloy, polyether-ether-ketone (PEEK), and high-temperature resin, using both subtractive and additive processes, with topological optimization. Mass reductions of up to 22% achieved through optimization translate into cost and environmental impact savings of 30–45% during production and use phases, although with potential service life reductions of up to 50% for polymeric materials. LCA and LCC analyses highlight production and use as the dominant life cycle phases, with end-of-life (EoL) impacts being comparatively minor. Sensitivity analysis shows that: (i) cost-prioritized scenarios select optimized steel molds; (ii) scenarios prioritizing lightweight design and environmental performance select advanced polymers and additive manufacturing; (iii) balanced scenarios identify PEEK as the optimal solution. The proposed framework enables the concurrent selection of material and technology aligned with design objectives and geometric optimization, providing quali-quantitative support for sustainability-oriented industrial decision-making across the life cycle.

Abstract: The use of composite materials and specifically of Fiber Reinforced Polymers (FRP) is continuously increasing in structural applications due to their high strength-to-weight ratio. From an environmental perspective, composites still face relevant challenges due to impactful petroleum-based matrices and large amounts of waste generated during manufacturing processes. This study proposes the reuse of FRP machining waste as filler in Masked Stereolithography (M-SLA) 3D printing. Scraps from FRP laminates, obtained during drilling operations, were incorporated into a photocurable resin and used to print tensile and flexural specimens with increasing filler contents (0–5 wt%) and mechanical characterization tests were carried out. A cradle-to-grave Life Cycle Assessment (LCA) was performed to quantify the potential environmental benefits associated with the reduced use of virgin resin. Results show that the use of recycled FRP waste leads to a loss of tensile strength and stiffness (up to 61% and 21% respectively) but it also provides a reduction in Global Warming Potential (about 2% at 5 wt% filler). This demonstrates that the proposed strategy can improve the sustainability of 3D-printed components, especially for non-structural applications.

Abstract: This work focuses on the pultrusion of pre-consolidated tapes made of virgin polypropylene reinforced with glass fiber. A specially designed laboratory-scale pultrusion line was used, consisting of a heating/forming mold, a cooling mold, and the pulling system. A life cycle assessment was conducted to evaluate the environmental impact of producing a pultruded composite material with a constant cross-section of 100 mm² and a length of one meter. The cradle-to-gate approach was chosen to model the pultrusion process, which involves the three stages mentioned above. The analysis was performed using the CML 2016 method in the LCA for Experts (Sphera) software. The data used in this work to model the cradle-to-gate scenario are mainly derived from experimental measurements taken during the pultrusion process using sensors and from the literature. The specific Energy Consumption (SEC) was calculated for both operational conditions (1.41 MJ/m at v120 to 0.905 MJ/m at v180). Despite the defects found, the samples taken from the pultruded profile showed significant interlaminar shear strength (120 mm/min of 83.7 ± 9.6 MPa compared to 63.5 ± 17.3 MPa at 180 mm/min).

Abstract: Additively manufactured Nitinol components often exhibit rough surfaces and defects that affect functional performance. This study investigates the feasibility of electropolishing Nitinol in a deep eutectic solvent (ethaline). Linear sweep voltammetry was used to identify anodic potentials suitable for controlled dissolution, and electropolishing was performed at selected potentials. Surface evolution was analysed by SEM, EDX, optical microscopy, and confocal microscopy. Electropolishing in ethaline effectively reduced surface scratches and produced more homogeneous surfaces without altering alloy composition. Higher applied potentials (12.5 V) resulted in complete removal of surface scratches and visually homogeneous surfaces, whereas lower potentials (6 V) mainly reduced the visibility of surface scratches. Compared to conventional inorganic electrolytes, the process exhibits a lower dissolution rate, offering a safer and more controllable approach.

Abstract: This study applies Life Cycle Assessment (LCA) using OpenLCA software in accordance with ISO 14040/14044 standards. A two-story school building was modeled with reinforced concrete and structural steel systems, both designed using ETABS. The study looks at a two-story school building over several phases, such as getting materials, making them, building them, using them, and then getting rid of them. Key performance indicators such as carbon emissions, energy consumption, recyclability, and construction waste are analyzed. Results reveal that concrete structures emit 27% less CO₂ and consume 55% less energy than steel systems, though steel offers superior recyclability (98%). The results show that steel structures may be recycled and used again and again, whereas reinforced concrete uses substantially less energy and carbon. The study proposes the use of hybrid systems that combine concrete slabs and foundations with steel superstructures to actualize these results. It also proposes employing materials that are good for the environment, such fly ash and recycled aggregates, and establishing national databases to assist people choose products. These suggestions are a practical way to get Iraq to embrace green building laws and practices.

Abstract: In order to improve the mechanical performance and sustainability of road rehabilitation operations, this research sought to examine the effects of adding sugarcane bagasse ash and polyester fibers to Babylon soil on certain geotechnical parameters. Throughout the course of the experiment, soil was amended using ash alone, with and without polyester fibers, and finally with a mix of the two additives. Particularly, the results demonstrated a considerable improvement in the soil's surface bearing capacity, unconfined compressive strength, and ideal moisture content. The maximum dry density dropped even more, as one would anticipate when dealing with less dense materials than thick soil particles. The study indicates that a 20% polyester to 15% ash ratio is the optimal ash to polyester ratio. This study adds to the growing body of information suggesting that using recycled materials might enhance soil behavior. If this holds, it may reduce environmental damage by allowing newly constructed infrastructure in areas with poor soil to be replaced with recycled materials.

Abstract: Environmental worries have increased due to the sharp rise in single-use plastics in healthcare institutions, especially with relation to medical plastic waste. This study explores the viability of using low-cost, small-scale technology to recycle such trash into goods with added value. Samples of medical plastic, such as vials, syringes, and bottles of intravenous solution, were gathered at Al-Shamiya General Hospital, sanitized, and mechanically destroyed. Two processing units were created: a 3D printing filament extruder and a manual injection molding machine. While the injection molding machine generated molded components based on the applied mold design, the extruder successfully produced filaments suitable with fused deposition modeling. The technical feasibility of converting sterilized medical plastics into useful products for everyday use and healthcare was validated by experimental results. The results highlight the potential of decentralized recycling strategies to lessen the environmental impact of medical waste, promote circular economy principles, and decrease plastic pollution, so long as stringent safety and sterilizing measures are followed.

Abstract: This study presents a comprehensive cost-benefit analysis of formwork systems commonly used in the Nigerian construction industry. The research evaluated the economic viability and overall impact of traditional timber and prefabricated steel formwork systems in Nigeria construction projects. The study employs a quantitative method through data collection from questionnaires and Life Cycle Cost (LCC) analysis. The findings indicated that fabricated steel formwork is durable, cost-effective, and promotes environmental sustainability compared to traditional timber formwork. The initial cost of timber formwork was found to be 19.76% cheaper than the fabricated steel formwork. However, the LCC analysis suggests that the cost of timber formwork is 5% higher than that of fabricated steel formwork. Therefore, this research provides actionable recommendations for construction stakeholders to optimize formwork selection, enhance economic efficiency, and promote sustainable construction practices in Nigeria’s construction industry.

Abstract: The partial substitution of cement with ground blast furnace slag (GGBS) and silica fume (HS) in the concrete mix has the potential to reduce the carbon footprint associated with cement production. The objective of this study is to evaluate the feasibility of this partial replacement as a strategy to promote greater sustainability in construction. The research looks at four replacement percentages with different ratios: 10% HS, 10% GGBS, a combination of 10% GGBS and 10% HS, and 13% GGBS with 10% HS. The results indicate that the mixtures obtained not only reach but exceed the required strength of f´c=280 kg/cm² and have a reduced carbon footprint compared to conventional concrete. This highlights the environmental benefits of using industrial by-products as partial replacements in concrete manufacturing, helping to mitigate the negative impacts of cement production.