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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 271 records · Page 15

Recycling Disassembled Automotive Plastic Components for New Vehicle Components: Enabling the Automotive Circular Economy

As the automotive industry increasingly relies on plastic components to meet fuel efficiency and emissions targets, the challenge of managing end-of-life vehicle (ELV) plastics continues to grow. Currently, more than 80% of ELV plastics in the U.S. are landfilled due to limited economic incentives and technical barriers to recycling. This study examines a mechanical recycling pathway for thermoplastic components disassembled from ELVs and assesses their usability for reintegration into new vehicle parts. Four representative materials were chosen based on material labels embedded in recovered parts and aligned with their virgin industrial equivalents: polypropylene (PP), 10% talc-filled PP (PP-T10), 20% talc-filled PP (PP-T20), and a 20% glass-/mineral-filled polyamide (PA6 + GF7 + MF13). The materials underwent shredding, drying, and injection molding before being characterized by particle size analysis, density measurement, thermal analysis (TGA, DSC), mechanical testing, and heat deflection temperature (HDT) evaluation. The results in this work indicated that minor differences in crystallinity were observed and small differences between model materials and ELV materials could have contributed to these changes. Mechanical testing revealed that neat polypropylene suffered a 15–20% reduction in stiffness and tensile strength, but talc-filled polypropylene and glass/mineral-filled nylon retained >90% of their modulus, strength, and heat deflection temperature values relative to virgin controls. Differences between virgin and ELV materials could have been attributed to use life degradation, contamination during use life, or even chemical/processing differences in model materials and ELV materials. However, these findings suggest that mechanically recycled, disassembled ELV plastics can retain sufficient structural performance to support circularity efforts in the automotive sector.

automotive recycling↗

Circular Perspective for Utilization of Industrial Wastewaters via Phytoremediation

Wastewater generated in municipal rendering facilities requires multi-step treatment, but it may also serve as a source of nutrients and water and thus may be valorized before or instead of the necessary wastewater treatment operations. In this work, wastewaters from a composting plant were utilized to support the growth of Miscanthus x giganteus, known as both a remediation plant and an energy biomass source. A pot experiment was established to compare the effects of different wastewater doses (0, 50, 100, and 200 mL per pot per week) on the miscanthus biomass yield, phytoextraction of heavy metals, biomass heat of combustion, and plant condition. The increase in the wastewater dose resulted in increases in both biomass yield (from about 44 to 139%) and biomass heat of combustion (from 7 to 17%) when compared to the control sample, with no adverse effects on plant physiological parameters. The highest concentrations of metals were found in miscanthus grown with the highest dose of wastewaters. It was found that higher wastewater dose correlates to both higher phytoextraction and phytorecovery of metals from plant substrate and wastewaters. The highest metal uptake was identified for Fe (431 mg·pot −1 ), followed by Al, Zn, Mn, Cu, Ni, Cr. The lowest metal uptake was noted for Pb, Co and Cd (0.88, 0.11, and 0.95 mg·pot −1 , respectively). The results indicate that miscanthus can be recommended for industrial wastewater treatment. In addition, due to high absorption efficiency of the substrate components, miscanthus can be used as a remediation tool, e.g., for the ecological stabilization of remediation of metal-polluted soils, especially in municipal facilities like rendering plants. This presents a circular perspective for the valorization of post-fermentation wastewaters with subsequent growth of energy crops, with other potential benefits for the environment, such as soil treatment, absorption of CO 2 , and air purification.

Miscanthus x giganteus↗

A Carbon Dioxide Refinery: The Core of a Sustainable Carbon-based Circular Economy

The atmospheric carbon dioxide (CO 2 ) accumulation (2–2.5 ppmv/year) is the result of the enormous gap between its emissions (37 Gton/year) and its capture, storage, and utilization (<500 Mton/year). Climate has been dramatically affected due to the failure of natural sinks, in working effectively. To address this Gton-scale gap, numerous uses and applications are needed particularly, those consuming vast volumes of this compound and/or rendering longevous products or long lifecycle services. Thus, carbon utilization (CU) can be seen as the step to close the carbon cycle. Among CU, R&D on CO 2 chemical conversion has proposed a variety of processes, with different degrees of developmental maturity. These chemical process technologies could be efficiently and effectively integrated into refineries to upgrade emitted CO 2 . A technology pipeline consisting of a database of these processes and the technology market status should be defined based on published scientific results and patents. Then, an innovative top-down methodology is proposed to eco-design configurations of that refinery, to warrant a sustainable carbon cycle (in terms of energy, environment, and economy) and to change the ways of producing fuels, chemicals, and materials. Additionally, the proposed methodology could be used to identify research and development gaps and needs, for orienting science and technology investments and measures. Hopefully, sustainable CO 2 refineries will be implemented to close the carbon cycle of a circular C-based economy and underpin a decarbonized chemical industry.

54 ENVIRONMENTAL SCIENCES↗

THERMAL STRESSES IN CIRCULAR DISCS.

Analyses are presented for the elastic buckling of a thin circular disc subjected to a steady-state, two-dimensional, radially- symmetrical temperature gradient. Ritz minimizing procedure were used to evaluate parameters for the critical temperature difference and for the mode of buckling. Numerical solutions were obtained on a digital computer for the boundary conditions of inner radius fixed and outer radius either free or fixed for discs with diameter ratios of 1.25 to 12. values for the range of diameter ratios tested.

THERMAL STRESS↗