Increase Material Efficiency Research Articles

Achieving European Union strategic autonomy: circularity in critical raw materials value chains

Abstract Why is it important to understand the potential of circular economy for security? With the green transition in full swing and vulnerabilities in value chains as a consequence of the COVID–19 pandemic and Russian aggression towards Ukraine, this question has never been more timely. Titanium metal constitutes a poignant case, as it is a critical raw material essential for the strategic civil aerospace and defence sectors. In addition, circular economy solutions constitute a viable solution to mitigate import dependencies in the case of this particular raw material. The European Union, with one of the largest aviation industries globally, is dependent on titanium imports from Russia and the United States. The latter, in turn, (re)imports titanium scrap from EU aviation manufacturing to increase material efficiency and reduce costs through recycling. Based on extensive stakeholder interviews across several countries and quantitative trade data, this article presents a first-time analysis of how, in the case of the titanium value chain, circular economy solutions can support the EU Open Strategic Autonomy (OSA) objectives, as enshrined in the 2023 Critical Raw Materials Act. We suggest that in order for the EU to achieve both the OSA and decarbonization objectives, it is essential to prioritize the establishment of recycling facilities as part of reshoring of the mid-value titanium industry. With the prospect of Ukraine becoming an EU member state, this strategy could be complemented by investments into the decarbonization of the upstream value chain in Ukraine while meshing it further with the EU industrial base. We argue that such reshoring could be best achieved through careful intergovernmental and industrial negotiations between the US and EU stakeholders within the formerly established channels for aviation dispute resolutions and within the framework of Ukraine's postwar reconstruction and potential EU accession.

ELEMENTerial – Construction System Study for CLT Offcuts

The ELEMENTerial research project focuses on the development of an innovative design and construction system for Cross-Laminated Timber (CLT) offcuts. CLT construction, while offering advantages for automation, raises concerns about offcut waste, which constitute 5-10% of the material production in Estonian CLT timber industry. This research highlights the importance of aligning timber construction with circular economy principles by effectively utilising offcuts. The study focuses on the development of a design method, creating a versatile and holistic construction system that breaks away from traditional orthogonal designs. Algorithmic tools are employed to streamline the design process and to help manage the complexities of working with smaller elements. The outcomes include a geometric strategy, offering variable configurations for assembly in walls, floors, ceilings and openings. The research demonstrates the potential to automate and pre-rationalise the design process, providing design freedom beyond orthogonal constraints and shell structures. The applications range from shelters to facade systems, building extensions to potentially large-scale construction systems. This study offers environmental benefits and design flexibility in the construction industry. It holds a potential to guide the sector towards reduced waste and increased material efficiency, fostering sustainability and economic value from waste materials. The prospects for future research include further automation, refinement of connection details, and efficiency in production and material usage.

Mapping construction sector greenhouse gas emissions: a crucial step in sustainably meeting increasing housing demands

This paper examines the tension between needing to build more infrastructure and housing and simultaneously reduce greenhouse gas emissions (GHG) to avoid the most catastrophic impacts of climate change. This study uses an Environmentally Extended Input-Output approach to conduct a high-resolution top-down analysis of Canada’s national construction GHG emissions. Our findings highlight that Canada’s current construction practices cannot accommodate the construction required to restore housing affordability by 2030 without substantial environmental consequences. On a consumption life cycle basis, the construction sector was responsible for approximately 90 Mt CO2e in 2018, equivalent to over 8% of Canada’s total GHG emissions, while delivering less than a third of Canada’s annual housing needs. Residential construction was responsible for the largest share (42%) of total construction emissions. Overall, 84% of emissions are from material manufacturing and 35% of construction emissions are imported, underscoring the need for a comprehensive regulatory framework addressing both domestic and imported emissions. Under current construction practices (i.e. current material use patterns and emissions intensities), meeting Canada’s 2030 housing affordability and climate commitments requires an 83% reduction in GHG emissions per construction product (i.e. per home) compared to the 40% economy-wide reduction promised in Canada’s international reduction commitments. Mitigating the GHG gap between emission caps and housing demand calls for changes in the ratio of housing to other infrastructure (e.g. fewer roads, less fossil fuel infrastructure), new construction approaches (e.g. increasing material efficiency) and/or disproportionally allocating climate budget to construction. The implications of our study extend beyond Canada, offering valuable insights for other growing countries with climate goals. The results emphasize the urgency in considering and establishing sectoral GHG budgets for construction and for transformative changes in the construction sector to meet national GHG emission reduction commitments.

Concept for an innovative screw coupling system production process

The article presents the concept of an innovative approach to the production of a screw coupling system, a key element in rail vehicles. The use of ready-made components from various subsuppliers, combined with new quality control methods, offers an opportunity for a significant reduction in cost and production time while increasing the efficiency and flexibility of the process. Key stages of the production process are highlighted, from the selection of semifinished products, through quality control, to the final assembly and validation. The applied strategies can minimise waste, increase material efficiency, and have a positive impact on the environment. This study constitutes a significant contribution to the development of sustainable production in the railway industry, with an emphasis on organisational, process, and product innovations.

A quantitative framework to support the decision between traditional, selective, and hybrid assembly

High-technological products often consist of several components, each with varying feature values that are critical to the assembly’s quality. As traditional manufacturing involves random selection of components, strict tolerance ranges are typically set to limit their feature variability, increasing scrap rates and lowering material efficiency. By smartly combining components based on their measured features, selective and hybrid assembly allow for more relaxed tolerances and more efficient use of raw materials without affecting the final product’s quality. However, the increased logistical complexity involves additional operational costs, complicating the choice for the best strategy.This study presents a decision-making model for selecting from traditional, selective, and hybrid assembly. The model is formulated by first defining the cost functions for the corresponding expected assembly cost, and then analytically determining the optimal choice boundaries between the three methods based on the involved process parameters. Estimation methods for the instance-specific process parameters are then discussed before validating the model with a fully elaborated case study.Results confirm the need for a quantitative framework to support an informed choice as this strongly depends on the involved parameter values. This study aims to pave the way towards more sustainable manufacturing by supporting practitioners to identify the conditions whereby intelligent assembly methods, in addition to allowing for scrap reduction and increased material efficiency, also represent the most cost-effective option.

Effect of depositional strategy on surface roughness of Al-5%Mg wall fabricated via Cold Metal Transfer based Wire Arc Additive Manufacturing

Cold Metal Transfer (CMT) based Wire Arc Additive Manufacturing (WAAM) is the future-driven novel technology for fabricating complex metal components, having advantages like high deposition rates, increased material efficiency, lesser lead time, low heat input, and low cost. Despite of above advantages, the CMT-WAAM process possesses few limitations in terms of producing metal components with high geometrical accuracy. Al-Mg alloys are particularly appealing for their lightweight and exceptional mechanical properties, making them attractive for various industrial applications such as marine, automobile, aerospace, etc. In this study, an Al-5%Mg alloy single wall has been built through CMT-WAAM using Current at 110A, Travel Speed (TS) of 7 mm/sec, and Gas Flow Rate (GFR) of 15L /min. The effect of unidirectional and bidirectional deposition direction on the surface quality of the fabricated sample has been investigated. Surface roughness (Ra) tests were conducted at three different zones (upper, middle, and bottom) of the specimen wall before the machining operation using a taylor hobson surtronic tester. It is concluded from the results that the S2 wall (unidirectional) has more Ra value than the S1 wall (bidirectional) in all zones due to the presence of a humping defect which results in more waviness over the S2 wall’s surface. In the bidirectional strategy, the roughness value reduces by 8.567 % (upper zone), 9.95 % (middle zone), and 13.019 % (bottom zone) than the unidirectional strategy. Thereby establishing that the deposition direction tends to build WAAM wall with a better surface finish.

Effect of Printing Orientation on Product Quality and Overall Process Efficiency: an Experimental Investigation

Additive Manufacturing (AM) technologies, also known as 3D printing, are increasingly used to produce usable and appealing end products. Besides allowing greater design freedom, 3D printing can increase material efficiency and drastically reduce production time. However, processes are still lacking in the quality of products. Among dozens of parameters that can influence the printing process, the study analyses the impact of the printing orientation (PO) on the product's geometrical accuracy and the process's overall efficiency. An experimental analysis has been designed and executed. A Fused Deposition Modelling (FDM) machine has been used to print the specimens. In particular, the experimental results showed the influence of PO on the geometrical characteristics of the specimens (bending angle, torsion angle, deviations, flatness tolerance and thickness). Moreover, the variability of production time, cost and resource consumption by varying PO has been investigated. As expected, the worst geometrical performance is shown by upright specimens. Furthermore, the ANOVA analysis underlines that only the orientation of the specimen with respect to the Z-axes (flat, on-edge and up-right) is statistically significant for the geometrical accuracy of the specimens. The method ELECTRE I has been used as Multi Criteria Decision-Making Method to rank the build configurations according to the resulting product's geometrical accuracy, the process performance and decision-maker’s priorities.

Synthesis, characterization, and lead removal efficiency of orange peel powder and orange peel powder doped iron (III) oxide-hydroxide

Lead contamination in wastewater causes toxicity to aquatic life, the environment, and water quality, and it causes many human dysfunctions and diseases. Thus, it is necessary to remove lead from wastewater before discharging it into the environment. Orange peel powder (OP) and orange peel powder doped iron (III) oxide-hydroxide (OPF) were synthesized, characterized, and investigated lead removal efficiencies by batch experiments, adsorption isotherms, kinetics, and desorption experiments. The specific surface area of OP and OPF were 0.431 and 0.896 m2/g, and their pore sizes were 4.462 and 2.575 nm, respectively which OPF had a higher surface area than OP, whereas its pore size was smaller than OP. They were semi-crystalline structures that presented the specific cellulose peaks, and OPF also detected the specific iron (III) oxide-hydroxide peaks. The surface morphologies of OP and OPF were irregular and porous surfaces. Carbon (C), oxygen (O), calcium (Ca), O–H, C–H, C=C, C–O, C=O, and –COOH were observed in both materials. The pHpzc of OP and OPF were 3.74 and 4.46. For batch experiments, OPF demonstrated a higher lead removal efficiency than OP because of spending less on material dosage than OP, and OPF demonstrated high lead removal by more than 95% while OP could remove lead at only 67%. Thus, the addition of iron (III) oxide-hydroxide helped to increase material efficiency for lead adsorption. Both materials corresponded to the Freundlich model relating to physiochemical adsorption, and they also corresponded to a pseudo-second-order kinetic model relating to a chemisorption process. Moreover, both materials could be reusable for more than 5 cycles for lead adsorption of more than 55%. Therefore, OPF was potential material to apply for lead removals in industrial applications.

The synthesis, characterizations, and lead adsorption studies of chicken eggshell powder and chicken eggshell powder-doped iron (III) oxide-hydroxide

The contamination of lead in wastewater causes water quality problems, which is toxic to aquatic organisms and environment, so wastewater treatment is required before discharging to receiving water. Chicken eggshell powder (CP) and chicken eggshell powder-doped iron (III) oxide-hydroxide (CPF) were synthesized, characterized, and investigated lead removal efficiencies by batch experiments, adsorption isotherms, kinetics, and desorption experiments. The specific surface area and pore volume of CPF were higher than CP, whereas the pore diameter size of CPF was smaller than CP. The phase structures of both materials demonstrated semi-crystalline phases with presenting peaks of calcium carbonate. Their surface morphologies were irregular, rough, and uneven surfaces. In both materials, they detected carbon, calcium, oxygen, OH, NH, CO, CO, and CH. The point of zero charges (pHpzc) of CP and CPF were 4.47 and 4.83. For batch experiments, CPF demonstrated a higher lead removal efficiency than CP because of spending less material dosage and contact time than CP, and both materials had high lead removals at a lead concentration of 50 mg/L by more than 95 %. Thus, the addition of iron (III) oxide-hydroxide helped to increase material efficiency for lead adsorption. CP corresponded to the Langmuir model while CPF corresponded to the Freundlich model. In addition, both materials corresponded to a pseudo-second-order kinetic model relating to a chemisorption process. Moreover, both materials could be reusable for more than 5 cycles for lead adsorption of more than 77 %. Therefore, CPF was a potential material to apply for lead removals in industrial applications.

Rebound effects following technological advancement? The case of a global shock in ferrochrome supply

Novel recycling technologies aim at increasing material efficiency by turning former waste products into valuable reclaimed resources. A key question is whether such technologies really reduce primary resource consumption or instead stimulate aggregated market demand. In this study the consequences of a positive shock in ferrochrome supply to the global stainless steel value chain is assessed quantitatively. This new source might be unlocked by technology under development for the recovery of chromium from carbon and stainless steel slags. The aim of this study is to quantitatively assess the income and substitution effects of reclaimed ferrochrome along a part of the stainless steel value chain. The impact of the supply shock is analysed by means of a vector autoregression (VAR), a dynamic model where lagged values of all included variables estimate current state of the system. Additionally, the VAR model is extended to a structural vector autoregression (SVAR) to account for contemporary effects as well. Both the VAR and SVAR model indicate that additional ferrochrome supply leads to an increase in aggregated supply of stainless steel, in combination with a substitution effect between ferrochrome and nickel. The extended SVAR model additionally highlights that contemporaneous effects do play an important role as well to capture the direct rebound effect in the ferrochrome market when working with quarterly data. In other words, an additional supply of reclaimed ferrochrome triggers a complex combination of interactions and consequences, yet it does not necessarily lead to a lower overall material consumption. The main contributions of this paper are the assessment of direct rebound effects of supplying reclaimed metals along the value chain and the demonstration that quantifying the effects of circular strategies is feasible.

Snap-interlock module system: Exploring an alternative architectural construction method

Responding to the rise of temporary architecture motivated by fast changing cultural and societal interests, construction methods must be adapted to meet the needs of reconfigurable systems. The prototype of Snap-Interlock Module System (SIMS) proposed in this study aims to integrate the simplicity of dry stacking as a primitive construction method through a coordinated joint system in order to increase material efficiency and structural integrity. This study explores a method of stacking blocks using unique interconnecting mechanisms without bonding agents to allow for reconfigurability. The considered unit of SIMS is configured to have four legs with integrated hooks on both top and bottom, allowing each block to snap into four adjacent blocks on either end. The centerpiece is designed such that each block can individually possess geometric versatility toward organic growth of the whole system. Larger assemblies of SIMS blocks can create full-scale structures without the use of bolting, welding, or other bonding agents. Finite element analysis demonstrates that the explored interlocking motion falls into the elastic range of the considered steel and confirms that structural integrity can be secured at the building scale as well. In order to test the proof-of-concept, 1:3 scaled Polylactic Acid (PLA) blocks are 3D printed and assembled into a 2.5 m tall portal frame, leading to a full-scale structural model executed with six full-scale steel blocks. The assembly and disassembly of both prototype structures are easily executed by a single individual. Despite the limitations of the chosen fabrication methods and material choices, the study promises diverse applications in the changing urban context and contributes to the broader sustainability of our built environment via an alternative and reconfigurable construction method.

Robust lightweight design and digital twins considering manufacturing quality variation and sustainability requirements

In this paper, robustness optimization of a fatigue-critical welded structure with measured misalignments and a generic robust design procedure are presented. The motivation for considering uncertainties, robustness and multi-criteria decision making in engineering design comes from the increasing sustainability requirements. Lightweight design of vehicles can reduce CO2 emissions and increase energy and material efficiency, but often the fatigue of welds limits the weight reduction. The manufacturing quality affects the fatigue strength of welds, and by quantifying the manufacturing quality and using robust design methodology the increasing sustainability requirements can be met, while also considering the technical and economical constraints. The surrogate model representing the relationship between the actual, measured geometry and the fatigue life can be used as the digital twin during operation.

May material bottlenecks hamper the global energy transition towards the 1.5 °C target?

Potentially scarce materials play an important role in many current and emerging technologies needed for a sustainable energy and mobility system. This paper examines the global demand for 25 potentially scarce materials that would result from an energy system that is compatible with the 1.5 °C target. It further analyses the risk for short- and mid-term material shortages. To determine the material requirements, an extensive prospective database was built up on the specific demand of these materials in key technologies. A second database describes the potential development of sub-technology market shares within a technology class. A material flow analysis model was used to determine the annual and cumulative material requirements as well as the recycling potential in the underlying scenario. The results show that production of all materials has to increase, in some cases significantly, in a short period of time to meet the demand for the energy and transportation system. In addition, the cumulative demand for some materials significantly exceeds current reserves and even resources. In particular, lithium (demand increase (DI) more than factor 10, cumulated demand (CD) exceeds reserves up to factor 2), cobalt (DI/CD: <7/<3), and nickel (CD/DI: <2.4/<1.4) for batteries, dysprosium (DI < 8) and neodymium (DI < 1.5) (for permanent magnets (wind turbines and electric motors), and iridium (DI < 2.9) as well as platinum (DI < 1.8) (fuel cells, electrolyzers) are affected. The construction of battery electric and fuel cell electric vehicles thus represents a major driver of the material demand. Depending on the material, shortages can be reduced or delayed by technology substitution, material recycling, technology lifetime extension, increased material efficiency, and a smaller future vehicle stock, but not entirely avoided. Hence, it can be expected that material bottlenecks will result in increasing material prices, at least in the short to medium term.

More than recycling – The potential of the circular economy shown by a case study of the metal working industry

The steel industry is responsible for a quarter of all industrial greenhouse gas emissions. So far, the environmental savings are mainly due to steel recycling. Besides recycling, the circular economy offers strategies to increase material efficiency and thus decrease the primary raw material demand. However, the potentials remain unexploited because circular economy concepts with a higher degree of circularity are not considered. The presented case study of an industrial machining knife illustrates how the production process can be improved by implementing various circular strategies. The environmental performance is analyzed by calculating and comparing the carbon footprint, the cumulative energy demand and the material footprint, and the material efficiency indicator. The results show that the implementation of the three overarching strategies of the circular economy - narrowing, closing, and slowing – contributes to a significant increase in material efficiency. The implementation also has a positive effect on the overall environmental performance. The circular production processes require less energy and resources and cause fewer emissions. Auxiliary processes such as additional transport routes are relevant, as they can reduce or even overcompensate for savings. These processes must be adequately considered and designed.

Topology Optimization and Fatigue Life Estimation of Sustainable Medical Waste Shredder Blade

There is an increased interest in designing cost-effective lightweight components to meet modern design requirements of improving cost and performance efficiency. This paper describes a significant effort to optimize the medical waste shredder blade through weight reduction by increasing material efficiency. The blade computer-aided design (CAD) model was produced through reverse engineering and converted to the finite element (FE) model to characterize von Mises stress and displacement. The obtained stress characteristics were introduced into the FE-SAFE for fatigue analysis. Furthermore, the FE model was analyzed through topological optimization using strain energy as the objective function while implementing the volume constraint. To obtain the optimal volume constraint for the blade model, several 3D numerical test cases were performed at various volume constraints. A significant weight reduction of 24.7% was observed for the 80% volume constraint (VC80). The FE analysis of optimal geometry indicated a 6 MPa decrease in the von Mises and a 14.5% increase in the fatigue life. Therefore, the proposed optimal design method demonstrated to be effective and easy to apply for the topology optimization of the shredder blade and has significantly decreased the structural weight without compromising the structural integrity and robustness.

Circular Economy and the triple bottom line in Norway

A more circular economy aims to reduce global material consumption, make the most out of our resources, and create a more sustainable economic system. In this paper, we analyze how different circular economy actions in Norway affect indicators in the three pillars of sustainable development: economic prosperity (measured by value added), social equity (measured by employment opportunities), and environmental protection (measured by greenhouse gas emissions). Based on priorities of the EU’s Circular Economy Action Plan and characteristics of the Norwegian economy, we have selected five value chains for analysis: electronics; textiles; construction and building; packaging and plastics; and metal efficiency. The results show that there is a substantial potential for increased value added and employment in Norway related to the circular transition, while at the same time mitigating greenhouse gas emissions. For increased material efficiency (plastic packaging, metals), employment gains can be substantial, while imports of metals and plastics decrease, resulting in lower upstream emissions, but higher Norwegian emissions. For consumer goods (textiles, electronics), the positive effects come about from shifting from a buy-and-discard model to a buy-repair/share/use longer model, resulting in increased employment in Norway and decreased imports, which potentially leads to lower emissions, but also lower employment globally. For re-use/re-purpose and recycling of building materials, emission-intense material extraction and processing activities are replaced by more labour intense activities, but has the largest potential of decreasing emissions within Norway.

Improved Copper Circularity as a Result of Increased Material Efficiency in the U.S. Housing Stock.

Material efficiency (ME) can support rapid climate change mitigation and circular economy. Here, we comprehensively assess the circularity of ME strategies for copper use in the U.S. housing services (including residential buildings and major household appliances) by integrating use-phase material and energy demand. Although the ME strategies of more intensive floor space use and extended lifetime of appliances and buildings reduce the primary copper demand, employing these strategies increases the commonly neglected use-phase share of total copper requirements during the century from 23–28 to 22–42%. Use-phase copper requirements for home improvements have remained larger than the demand gap (copper demand minus scrap availability) for much of the century, limiting copper circularity in the U.S. housing services. Further, use-phase energy consumption can negate the benefits of ME strategies. For instance, the lifetime extension of lower-efficiency refrigerators increases the copper use and net environmental impact by increased electricity use despite reductions from less production. This suggests a need for more attention to the use phase when assessing circularity, especially for products that are material and energy intensive during use. To avoid burden shifting, policymakers should consider the entire life cycle of products supporting services when pursuing circular economy goals.

Supply of wood processing residues – a basic calculation approach and its application on the example of wood packaging

Waste reduction, recycling and increased material efficiency are key objectives in complex industrial ecology. The wood processing industry also aims at a more intensive resource recovery and usable residual volumes. Important volumes of wood processing residue potentials can be found at the EU level. However, to date no reliable calculation approach has been established. To fill the information gap, this study presents an approach for calculating the supply of wood processing residues. The methodological approach follows the concept of a material flow analysis. We quantify the material flows based on product-specific conversion factors and the coefficients of material efficiency. This paper intends to develop a calculation approach based on existing statistical data from official classifications such as Prodcom. We perform the calculation approach on standardised wood packaging products at the European level. The calculated supply of wood processing residues the European Union in 2018 was 29.7 million m³f with a total material input of about 70.8 million m³f and a production volume of 40.8 million m³f. A maximum volume of 29.6 million m³f sawnwood is used for the production of wooden containers. Quantification results can be further differentiated – e.g., the share of sawmill by-products. Hence, the calculation approach supports the visualisation and understanding of material flows within the forest-based sector. Wood processing residue coefficients resulting from product specific MFA can be repeatedly applied to annual production data of wood products, wood composites and wood supply chains. Thus, the quantification of wood processing residues improves the results of existing and future wood resource balances including cascade uses by increasing their level of detail.

Closed-loop systems to circular economy: A pathway to environmental sustainability?

The global society faces an existential threat if it fails to meet current and future material needs of its populations, while staying within the carrying capacity of our planet. An approach that has been put forwards to address this complex challenge is to aim to close our society's material flows through introduction of a Circular Economy (CE). This paper provides an extensive literature review to understand the evolution of material circularity concepts and strategies, and their potential for increasing material efficiency and reduce environmental impacts towards meeting the material needs of our societies in an environmentally sustainable manner. Based on the review it can be concluded that CE may have a strong potential to help address the challenge. However, this requires broadening the focus of CE from technical and economical to political and socio-cultural dimensions, adopting a whole-systems approach, aiming to redesign economic and social relations to not just reduce the impact humanity has on the environment but actually achieve a balance in human-nature relations with a planetary boundary thinking. Pursuing purely technical and economic avenues to implement CE for increasing material circulation and sustainable growth on the foundation of our current linear economic system, will not achieve its full potential. It will not be sustainable but continue to produce the challenges that we currently have.

Finite element analysis of a spring isolator

Composite material and vibration are the main research areas in which today’s industries are growing. Vibration isolator is a material which is used in mechanical industries to reduce vibration of machine by placing them at the bottom of small and heavy machineries under dynamic conditions. In designers and engineering life, composite materials help to increase material efficiency resulting in the reduction of cost and for utilization of resources as best as possible. Generally, composite materials are wide in automobile sectors, manufacturing industries. In this paper, study on isolator involves aluminium alloy and grey cast iron and compared the parameters and observed that the grey cast iron is observed the suitable material for vibration isolator. The design model was designed using CATIA and analyses have been performed using ANSYS Workbench.