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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 55 records · Page 3

Chemical sensors for space applications

The payload of the Space Station Freedom will include sensors for frequent monitoring of the water recycling process and for measuring the many biochemical parameters related to onboard experiments. This paper describes the sensor technologies and the types of transducers and selectors considered for these sensors. Particular attention is given to such aspects of monitoring of the water recycling process as the types of water use, the sources of water and their hazards, the sensor systems for monitoring, microbial monitoring, and monitoring toxic metals and organics. An approach for monitoring water recycling is suggested, which includes microbial testing with a potentiometric device (which should be in first line of tests), the use of an ion-selective electrode for inorganic ion determinations, and the use of optic fiber techniques for the determination of total organic carbon.

Bonting, Sjoerd L.↗

Assessment of Different Application Grades of Post-Consumer Recycled (PCR) Polyolefins from Material Recovery Facilities (MRFs) in the United States

The recycling of plastics has been gaining traction in the following years as many companies, organizations, and governments are pushing toward a more circular economy. However, plastic recycling rates are still small compared to those of plastic production, especially for polyolefins, such as high-density polyethylene (HDPE) and polypropylene (PP). With the goal of finding applications for recycled plastic resin, recyclers can face some challenges associated with the heterogeneity in the polymer properties of plastic waste streams, which could hinder the full potential of recycling due to the lack of a consistent feedstock. Here, this study assessed how an additional sorting step of recycled HDPE and PP streams, separating them into two categories based on the previous application, impacts the recycled polymer properties, such as physical, molecular, and thermal. It was demonstrated that manually separating HDPE articles previously processed by extrusion blow molding (EBM) or injection molding (IM) and PP articles by thermoforming (TF) or IM could yield recycled resins with more consistent properties, considering the significant differences between them. This highlights that an additional sorting step would allow recyclers to target more premium or currently unattainable plastic processing applications with postconsumer recycled (PCR) resins, which could significantly promote an increase in plastic recycling rates. Nevertheless, the development of new technologies is needed to automate this extra sorting step, as with the increase in scale manual sortation could not be feasible and cost-effective, reducing the attractiveness of using PCR resins in comparison to virgin ones.

36 MATERIALS SCIENCE↗

Multiscale porous elastomer substrates for multifunctional on-skin electronics with passive-cooling capabilities

In addition to mechanical compliance, achieving the full potential of on-skin electronics needs the introduction of other features. For example, substantial progress has been achieved in creating biodegradable, self-healing, or breathable, on-skin electronics. However, the research of making on-skin electronics with passive-cooling capabilities, which can reduce energy consumption and improve user comfort, is still rare. Herein, we report the development of multifunctional on-skin electronics, which can passively cool human bodies without needing any energy consumption. This property is inherited from multiscale porous polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) supporting substrates. The multiscale pores of SEBS substrates, with characteristic sizes ranging from around 0.2 to 7 µm, can effectively backscatter sunlight to minimize heat absorption but are too small to reflect human-body midinfrared radiation to retain heat dissipation, thereby delivering around 6 °C cooling effects under a solar intensity of 840 W∙m -2 . Other desired properties, rooted in multiscale porous SEBS substrates, include high breathability and outstanding waterproofing. The proof-of-concept bioelectronic devices include electrophysiological sensors, temperature sensors, hydration sensors, pressure sensors, and electrical stimulators, which are made via spray printing of silver nanowires on multiscale porous SEBS substrates. The devices show comparable electrical performances with conventional, rigid, nonporous ones. Also, their applications in cuffless blood pressure measurement, interactive virtual reality, and human–machine interface are demonstrated. Notably, the enabled on-skin devices are dissolvable in several organic solvents and can be recycled to reduce electronic waste and manufacturing cost. Such on-skin electronics can serve as the basis for future multifunctional smart textiles with passive-cooling functionalities.

42 ENGINEERING↗

Manganese Oxidation during Vegetation Burning

Redox recycling of manganese (Mn) plays a key role in organic matter decomposition and nutrient cycling in terrestrial vegetated ecosystems, and it is expected to be changed by fires. This study revealed how Mn is oxidized during vegetation burning, by characterizing the chemical speciation of Mn in fire ash from wildland fires and laboratory burning and evaluating the factors governing its average oxidation state (AOS) and speciation. Manganese in wildland fire ash from different ecosystems showed variable AOS that ranges from 2.5 to 3.3. Laboratory burning experiments showed that Mn oxidation was primarily controlled by fire thermal intensity (temperature × duration) and burning completeness. As heating time increased from 5 min to 5 h at 550 and 700 °C, Mn AOS in the lab-burned vegetation ash increased from 2.7 to 4.0 and the oxidation rate was faster at higher temperature. Diverse Mn species can present in wildland fire ash and differ structurally from biogenic Mn oxides. The oxidized Mn species enable fire ash to mediate oxidative degradation of catechol, demonstrating its potential in mediating organic matter decomposition. This study revealed a new paradigm of Mn redox recycling, as compared to the microbe-mediated Mn redox cycling in the absence of fires.

36 MATERIALS SCIENCE↗

Utilization of Ultrasonication as a Method of Reducing Organic and Inorganic Contamination in Post‐Consumer Plastic Film Waste

Post-consumer plastic film waste often carries organic and inorganic contaminants that challenge recycling processes and affect the quality of recycled products. An effective contaminant removal procedure through washing such single-used plastic films (SUPFs) can address environmental and waste management concerns. This study compares the efficiency of different washing techniques in reducing SUPF contamination. To evaluate the efficacy of each washing technique, film samples collected from material recovery facilities are individually exposed to friction, ultrasonic-assisted, and a combination of both washes. Thermal analysis indicates that the polymers' melting temperature, crystallization temperature, and crystallinity remain unaffected by the washing methods, demonstrating method aptness. Confocal laser scanning microscope images show that washing results in a cleaner sample surface. 91% ash reduction during the combined wash treatment indicates a high method efficiency compared to the individual friction and ultrasonic wash procedures. This is further validated by reducing characteristic contaminant IR bands (3600–3000, 1750–1600, and 1100–1000 cm −1 ). Elements of concern such as Cd, Cr, Hg, and Pb in SUPFs after each washing technique applied conform with regulations (<100 ppm) for packaging products. This research shows the novel ultrasonic washing reduces more contamination than friction with shorter wash times and no surfactants.

42 ENGINEERING↗

Exobiochemistry

Exobiochemistry is the putative biochemistry of extraterrestrial life. It suggests the possible energy and material bases of extraterrestrial life and could help detect it. The diverse biochemistry of Earth indicates that a wide range of exobiochemistry is possible on other planets. An exobiochemistry will probably use the same energy sources as Earths ecology, light, biological organic material, and more rarely abiotic chemicals. Extraterrestrial life will be based on familiar chemical principles and probably capture, store, and release energy using oxidation-reduction reactions. Extraterrestrial life will give chemical indications of its existence. Key elements will be concentrated, stored, and recycled, altering their availability and isotopic composition. Any significant departure from chemical equilibrium would be good evidence for exobiochemistry, but an integrated system of departures from the expected equilibrium would be better. Exobiochemistry can be expected to include closed biogeochemical cycles of the major life supporting elements and may well show the complex dynamic close-coupled interactions that characterize the terrestrial biosphere. Terrestrial biochemistry provides a basis for generalization and extrapolation but it does not set bounds on exobiochemistry. In exobiochemistry we can expect: 1. closed chemical cycles that recycle materials, nutrients, and catalysts, 2. organisms with complementary metabolisms that cooperate to close the chemical cycles, 3. a high probability of a carbon and water chemistry, but some possibility of a non-carbon or non-water chemistry in extreme environments, and, 4. life similar to bacteria more prevalent than higher plants and animals.

Jones, Harry↗

Biofilms and the survival of opportunistic pathogens in recycled water

Microorganisms are likely to develop an organic film on pipes, water reservoirs and filters used for waste water reclamation during extended missions in space. These biofilms can serve to protect and concentrate potentially pathogenic microorganisms. Our investigation has emphasized the survival strategy of opportunistic pathogenic bacteria in distilled water. Pseudomonas aeruginosa and Staphylococcus aureus were used as test organisms. Cultures were incubated at 10 degrees, 25 degrees, and 37 degrees C. No viable Staphylococcus cells were detected after the first week of incubation. P. aeruginosa, however, survived in distilled water up to 5 months at all three temperatures tested. The starved cells were able to form a biofilm layer on stainless steel. The cells exhibited a negative surface charge. The charge may be involved in the adhesion of this bacterium to metal substrata. We are currently investigating the importance of adhesion in the survival of this and other potential human pathogens found in water recycling systems.

NASA Discipline Life Support Systems↗

Comparison of aerobically-treated and untreated crop residue as a source of recycled nutrients in a recirculating hydroponic system

This study compared the growth of potato plants on nutrients recycled from inedible potato biomass. Plants were grown for 105 days in recirculating, thin-film hydroponic systems containing four separate nutrient solution treatments: (1) modified half-strength Hoagland's (control), 2) liquid effluent from a bioreactor containing inedible potato biomass, 3) filtered (0.2 micrometer) effluent, and 4) the water soluble fraction of inedible potato biomass (leachate). Approximately 50% of the total nutrient requirement in treatments 2-4 were provided (recycled) from the potato biomass. Leachate had an inhibitory effect on leaf conductance, photosynthetic rate, and growth (50% reduction in plant height and 60% reduction in tuber yield). Plants grown on bioreactor effluent (filtered or unfiltered) were similar to the control plants. These results indicated that rapidly degraded, water soluble organic material contained in the inedible biomass, i.e., material in leachate, brought about phytotoxicity in the hydroponic culture of potato. Recalcitrant, water soluble organic material accumulated in all nutrient recycling treatments (650% increase after 105 days), but no increase in rhizosphere microbial numbers was observed.

NASA Discipline Life Support Systems↗

Emiliania huxleyi —Bacteria Interactions under Increasing CO 2 Concentrations

The interactions established between marine microbes, namely phytoplankton–bacteria, are key to the balance of organic matter export to depth and recycling in the surface ocean. Still, their role in the response of phytoplankton to rising CO 2 concentrations is poorly understood. Here, we show that the response of the cosmopolitan Emiliania huxleyi (E. huxleyi) to increasing CO 2 is affected by the coexistence with bacteria. Specifically, decreased growth rate of E. huxleyi at enhanced CO 2 concentrations was amplified in the bloom phase (potentially also related to nutrient concentrations) and with the coexistence with Idiomarina abyssalis (I. abyssalis) and Brachybacterium sp. In addition, enhanced CO 2 concentrations also affected E. huxleyi’s cellular content estimates, increasing organic and decreasing inorganic carbon, in the presence of I. abyssalis, but not Brachybacterium sp. At the same time, the bacterial isolates only survived in coexistence with E. huxleyi, but exclusively I. abyssalis at present CO 2 concentrations. Bacterial species or group-specific responses to the projected CO 2 rise, together with the concomitant effect on E. huxleyi, might impact the balance between the microbial loop and the export of organic matter, with consequences for atmospheric carbon dioxide.

54 ENVIRONMENTAL SCIENCES↗

Polypeptide-based batteries toward sustainable and cyclic manufacturing

Mass demand for lithium-ion batteries (LIBs) consumes enormous resources, thus having a great impact on the battery supply chain. Here, it is essential to create a sustainable manufacturing cycle for LIBs. Recently in Nature, Wooley and collaborators reported an all-polypeptide organic radical battery, demonstrating the potential of sustainable, recyclable metal-free batteries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Non-catalytic oxidative depolymerization of lignin in perfluorodecalin to produce phenolic monomers

We demonstrate for the first time non-catalytic, oxidative cracking with molecular oxygen (O 2 ) to depolymerize native lignin into oxygenated phenolic monomers. Maximum monomer yield of 10.5 wt% was achieved at 250 °C after only 10 min of reaction and included vanillin, syringaldehyde, vanillic acid, and syringic acid. High rates of oxidation are attributed to the use of perfluorodecalin as solvent. Perfluorodecalin is a perfluorocarbon (PFC), characterized by their chemical stability and exceptionally high solubility for O 2 . Monomer yields were typically five-fold higher in perfluorodecalin compared to solvents more commonly employed in lignin conversion, such as methanol, butanol, acetonitrile, and ethyl acetate. Phenolic monomer production in perfluorodecalin favors high temperatures and short reaction times to prevent further oxidation of the produced monomers. Lignin oil obtained under oxidative conditions in perfluorodecalin showed lower molecular weight and smaller polydispersity compared to other solvents. Increasing the reaction time further decreased the molecular weight, while increasing reaction time in an inert atmosphere increased the molecular weight of the lignin oil. High concentrations of O 2 in perfluorodecalin not only increased lignin depolymerization but suppressed undesirable condensation reactions. Depolymerization is likely initiated by thermally induced homolytic cleavage of ether linkages in lignin to form phenoxy and carbon-based radicals. These radicals bind with O 2 as a radical scavenger and further react to form phenolic monomeric products rather than repolymerizing to large oligomers. The PFC process was scaled from 5 mL to 250 mL without any loss of yield. Because most organic compounds are not soluble in perfluorodecalin, recycling is easily achieved via liquid–liquid separation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

System and method for extracting ethanol from a fermentation broth

The present invention is directed to a system and method for producing an organic compound using fermentation wherein multiple components of the system are recycled within the system. The system and method allow for extraction of a high concentration of the organic compound from the fermentation broth in a continuous system that allows recycling of the biomass, aqueous fermentation broth and extraction solvents. The system and method are particularly well adapted for producing and extracting ethanol.

09 BIOMASS FUELS↗

Electrochemically Initiated Depolymerization of Poly(Methyl Methacrylate)

Efficient depolymerization of polymers with all-carbon backbones under mild conditions would be valuable in chemically recycling commodity plastics. Poly(methyl methacrylate) (PMMA) is a commodity thermoplastic that is currently depolymerized under temperatures in excess of 400 °C. Herein, we lower the temperatures needed to achieve depolymerization of PMMA by performing radical generation and depropagation with orthogonal stimuli. This first demonstration of electrochemically initiated PMMA depolymerization relies on reduction of phthalimide esters that, upon subsequent decarboxylation, generate polymer-centered radicals. These radicals then spontaneously unzip the polymer back to its monomeric constituents at temperatures as low as 105 °C. We studied the mechanism and efficiency of this transformation as a function of phthalimide ester placement, incorporation density, and polymer molecular weight. We found that chain-end activation is effective for modest molecular weights but suffers diminished efficiency at higher degrees of polymerization. In contrast, pendent-group activation is more effective for depolymerizing higher molecular weight species. Integrating higher molar amounts of phthalimide ester pendants leads to more effective depolymerization, with >95% depolymerization in copolymers with 5 mol% phthalimide ester incorporation. We leveraged this understanding to create a custom electro-distillation apparatus that allowed us to simultaneously electrochemically depolymerize PMMA and directly distill methyl methacrylate in >22% yield, which could ultimately be repolymerized. These findings establish electrochemistry as a versatile and orthogonal stimulus for vinyl polymer depolymerization and provide a foundation for closed-loop electrochemical recycling of widely used plastics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

System and method for extracting ethanol from a fermentation broth

The present invention is directed to a system and method for producing an organic compound using fermentation wherein multiple components of the system are recycled within the system. The system and method allow for extraction of a high concentration of the organic compound from the fermentation broth in a continuous system that allows recycling of the biomass, aqueous fermentation broth and extraction solvents. The system and method are particularly well adapted for producing and extracting ethanol.

Abbas, Charles↗

Chapter 4: Chemical Recycling of PET

The circular economy of poly(ethylene terephthalate) (PET) today is dominated by collection, sorting, cleaning, melting, and re-processing of transparent bottles via mechanical recycling. This has a better environmental impact as assessed by Life Cycle Assessment (LCA) (e.g. uses less non-renewable energy and produces less greenhouse gases) than production of virgin resin and is the preferred method of recycling wherever possible. However, not all PET products can be recycled this way and there is forecast to be a large shortfall between supply of high quality recycled PET (rPET) and the demands of large users who have made commitments to use more recycled resin over the next 5 - 10 years. Consequently, there is renewed interest, and increased activity, in chemical recycling, where waste PET is depolymerized, and the monomer(s) are purified and repolymerized into resin equivalent to that from petroleum-derived raw materials. The LCA is likely to be not as favorable as traditional mechanical recycling, but will likely be better than virgin PET and the process can be applied to a broader range of lower value wastes and thus promises to dramatically increase the overall recycling rate. In this chapter we will review the processes used in chemical recycling of PET, with the VolCat process from IBM as a detailed case study, followed by descriptions of the alternative technologies and emerging players in the field.

chemical recycling↗

Multi-omics reveals nitrogen dynamics associated with soil microbial blooms during snowmelt

Snowmelt triggers a soil microbial bloom and crash that affects nitrogen (N) export in high-elevation watersheds. The mechanisms underlying these microbial dynamics are uncertain, making soil nitrogen processes difficult to predict as snowpack declines globally. Here, integration of genome-resolved metagenomics, metatranscriptomics and metabolomics in a high-elevation watershed revealed ecologically distinct soil microorganisms linked across the snowmelt time-period by their unique nitrogen cycling capacities. The molecular properties and transformations of dissolved organic N suggested that degradation or recycling of microbial biomass provided N for biosynthesis during the microbial bloom. Winter-adapted Bradyrhizobia spp. oxidized amino acids anaerobically and had the highest gene expression for denitrification during the microbial bloom. A pulse of nitrate was driven by spring-adapted Nitrososphaerales after snowmelt, but dissimilatory nitrate reduction to ammonia (DNRA) gene expression indicated significant nitrate retention potential. These findings inform our understanding of nitrogen cycling in environments sensitive to snowpack decline due to global change.

Sorensen, Patrick O↗