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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Mitigating municipal solid waste fouling in biofuel conversion via screw surface modifications

Here, municipal solid waste (MSW)'s 40–60 % carbon content makes it a feedstock for biofuel production via pyrolysis. One challenge in the conversion process is MSW fouling due to thermal decomposition. The accumulated deposit on the injection screw often leads to plugging and constriction. This study examined the morphology and composition of the MSW fouling deposit and conducted a thermal simulation to understand the temperature gradience of the injection screw. Surface modifications including smoothening and anti-adhesion coating were proposed for the injection screw to address the deposit problem. For evaluating the candidate mitigations, a bench-scale fouling test was developed with the gas environment, temperature, and sliding speed relevant to the contact interface between the MSW particles and the screw. Results suggested that a smoother screw surface could reduce the grip and a non-metallic coating with a lower surface energy could decrease adhesion, consequently leading to less fouling. Specifically, reducing the roughness from 2 to 0.6 and then to 0.2 μm proportionally decreased the amount of deposit, and the diamond-like-carbon, CrN, and NiCr–CrC composite coatings effectively hindered the fouling process. This study provides fundamental insights into the MSW fouling and proof-of-concept of potential mitigations through the screw surface modification.

09 BIOMASS FUELS↗
DOE OSTI2023

HIV-1 protease inhibitors with a P1 phosphonate modification maintain potency against drug-resistant variants by increased interactions with flap residues

Protease inhibitors are the most potent antivirals against HIV-1, but they still lose efficacy against resistant variants. Improving the resistance profile is key to developing more robust inhibitors, which may be promising candidates for simplified next-generation antiretroviral therapies. Here, in this study, we explored analogs of darunavir with a P1 phosphonate modification in combination with increasing size of the P1′ hydrophobic group and various P2′ moieties to improve potency against resistant variants. The phosphonate moiety substantially improved potency against highly mutated and resistant HIV-1 protease variants, but only when combined with more hydrophobic moieties at the P1′ and P2′ positions. Phosphonate analogs with a larger hydrophobic P1′ moiety maintained excellent antiviral potency against a panel of highly resistant HIV-1 variants, with significantly improved resistance profiles. The cocrystal structures indicate that the phosphonate moiety makes extensive hydrophobic interactions with the protease, especially with the flap residues. Many residues involved in these protease-inhibitor interactions are conserved, enabling the inhibitors to maintain potency against highly resistant variants. These results highlight the need to balance inhibitor physicochemical properties by simultaneous modification of chemical groups to further improve resistance profiles.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Methodology to evaluate design modifications intended to eliminate frosting and high discharge temperatures in air-source heat pumps (ASHPs) in cold climates

Air-source heat pumps (ASHPs) operating in cold climates experience problems with frosting and high refrigerant temperatures. These problems increase energy consumption, and their severity depends on the climatic conditions. In the present paper, a methodology for identifying the prevailing problem between frosting and high discharge temperatures is presented. Three performance indices, the frosting index (FI), the discharge index (DI), and the total loss index (TLI), are proposed to quantify the impacts of frosting and high discharge temperatures on the annual performance of ASHPs in different climatic conditions. The FI and DI show which problem (frosting or high discharge temperature) dominates, and the TLI indicates the combined effect of frosting and high discharge temperatures on the performance of an ASHP. A thermodynamic model of an ASHP coupled with the TRNSYS building simulation tool is used to estimate the performance of an ASHP and the proposed loss indices to estimate the impact of both frosting and high discharge temperatures for 45 cities in Canada. The results can be extended to other parts of the world that experience similar climatic conditions The results reveal that in cities in ASHRAE climatic zones 5 and 6 (classified as cold regions) where the ambient air temperatures are predominantly between -15 °C to 6 °C, ASHPs are heavily impacted by frosting. The problem of high discharge temperatures in ASHPs is predominant in cities in climate zones 7 and 8 (classified as very cold and subarctic regions) where the temperatures are frequently below -20 °C in winter. Among the cities considered, St. John, NL has the highest fraction of heating hours experiencing frosting (90 %), where the annual increase in energy consumption due to frosting is 13.5 % of the annual heating energy consumption. The highest annual increase in energy consumption due to high discharge temperatures is in Isachsen, NU (zone 8), where the increase is 30 % of the annual heating energy consumption. Based on the proposed indices, another index called the performance gain index (PGI) is created, which can be used as a first step to assess the energy-saving potential of design modifications applied to ASHPs to solve the problems of frosting and high discharge temperatures. The PGI will aid in developing climate specific ASHPs. One possible design modification is the use of a two-stage ASHP with an economizer. It is observed that the two-stage ASHP with economizer can mitigate high discharge temperatures and improve performance in very cold and subarctic regions (zones 7 and 8). However, it is not as beneficial in zones 5 and 6, where the impact of high discharge temperatures on performance is minimal and frosting dominates. Finally, a case study, using the PGI to evaluate the economic and environmental effectiveness of a two-stage ASHP with economizer is presented for the city of Saskatoon.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Microwave-driven synthesis and modification of nanocarbons and hybrids in liquid and solid phases

Over the past 20 years, nanocarbons have become more significant as nanostructured fillers in composites and, more recently, as functional elements in a brand-new class of hybrid materials. Microwave-assisted synthesis and processing is a burgeoning subject matter in materials research with significant strides in the realm of nanocarbon during the last decade. Here, the review examines recent approaches to producing various nanocarbons using microwaves as energy sources, the characterization of such materials for various applications, and their results. The underlying factors supporting the increased performance of such materials or their composites are analyzed and reaction mechanisms are presented wherever necessary. In particular, the recently developed and verified approaches to produce porous carbon materials, CNTs and fibers, carbon nanospheres, carbon dots, CQDs, reduced graphene oxide, nanocarbon hybrid materials, and the purification and modification of CNTs are discussed. The reduction of graphene oxide and the preparation of graphene derivative hybrids using solid-state and liquid-state routes such as polyopl, mixed solvents, ionic liquids, and microwave-assisted hydrothermal/solvothermal methods are analyzed in detail. In addition, the principles of microwave heating in liquid and solid states, the use of metals particles as arcing agents or catalysts, and carbonaceous materials as internal or external susceptors during synthesis and modifications are presented in detail.

25 ENERGY STORAGE↗
DOE OSTI2026

Quantifying market volume sensitivity to material property modifications in polyhydroxybutyrate: A parametric analysis approach

Polyhydroxybutyrate (PHB), a biodegradable biopolymer, represents a promising alternative to petroleum-based thermoplastics. However, despite consistent market growth, PHB faces persistent commercialization challenges that limit widespread adoption. Existing research has focused predominantly on optimizing PHB production processes, leaving a critical gap in understanding which material property modifications would most effectively enhance market competitiveness. This study addresses this gap by systematically analyzing the relationship between polymer material properties and market performance using U.S. market data from 2008 to 2021 for 21 thermoplastic polymers across 19 material properties. We employed principal component regression to identify property modifications that could maximize market volume while reducing CO 2 emissions. Our parametric analysis revealed that two specific material properties – Hardness Shore A and Sheet Extrusion Temperature – significantly influence PHB marketability across different price points. Market simulations demonstrated that a 10% increase in Hardness Shore A could increase PHB market volume by 431.5 million kg while reducing emissions by 188.7 kg CO 2 . A similar 10% increase to Sheet Extrusion Temperature could yield a 297.5 million kg volume increase and a 99.2 kg CO 2 reduction in emissions. Critically, this approach is agnostic to the specific methods required to achieve these property changes, instead providing material scientists with quantitative, data-driven targets for R&D prioritization. Here, this framework offers a novel methodology for evaluating biopolymer competitiveness and supporting strategic decisions to accelerate PHB market adoption and contribute to decarbonization of the plastics industry.

09 BIOMASS FUELS↗
DOE OSTI2022

In-plane and through-plane dielectric properties of graphene oxide membrane: Effect of Al 3 + modification

A graphene oxide (GO) membrane can be used in structural dielectric capacitors and planar micro-supercapacitors as a dielectric separator material due to its excellent through-plane and in-plane dielectric properties. The ability to tailor the dielectric properties of the GO membrane is crucial for dielectric applications. We believe this to be the first demonstration describing how Al 3+ ions impact the dielectric properties of the GO membrane through cation to oxygenated functional groups interactions. In this work, the Al 3+ -modification to the GO membrane was realized through a facile pre-coordination method followed by layer-by-layer assembling. The influence of Al 3+ on the GO membranes’ through-plane and in-plane dielectric properties (dielectric constant and dielectric loss) was investigated in the frequency range from 0.01 Hz to 10 5 Hz. Plane-to-plane and edge-to-edge Al 3+ coordination with the functional group on the basal plane or edge of the GO sheets was proposed to understand the metal ion's impact on the dielectric properties. The results demonstrated that the Al 3+ modification was an effective strategy to tailoring the GO membranes’ dielectric properties in a low frequency regime and further suggested the possibility of designing dielectric GO membranes with controllable dielectric performance. At a low frequency range (0.01–1 Hz), the addition of Al 3+ increased the through-plane dielectric constant and decreased the in-plane dielectric constant. In terms of dielectric loss, unmodified GO membranes exhibited a higher in-plane dielectric loss than the through-plane dielectric loss. Al 3+ -modified GO membranes exhibited increased through-plane dielectric loss and decreased in-plane dielectric loss compared to the unmodified GO membranes.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Nuclear modification of $\Upsilon$ states in pPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

Production cross sections of Image 1, Image 2, and Image 3 states decaying into Image 4 in proton-lead ( p Pb ) collisions are reported using data collected by the CMS experiment at s NN = 5.02 TeV . A comparison is made with corresponding cross sections obtained with p p data measured at the same collision energy and scaled by the Pb nucleus mass number. The nuclear modification factor for Image 1 is found to be Image 5. Similar results for the excited states indicate a sequential suppression pattern, such that Image 6. The suppression of all states is much less pronounced in p Pb than in PbPb collisions, and independent of transverse momentum Image 7 and center-of-mass rapidity Image 8 of the individual Image 9 state in the studied range Image 10 and Image 11. Models that incorporate final-state effects of bottomonia in pPb collisions are in better agreement with the data than those which only assume initial-state modifications.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Observation of nuclear modification of energy-energy correlators inside jets in heavy ion collisions

Energy-energy correlators are constructed by averaging the number of charged particle pairs within jets, weighted by the product of their transverse momenta, as a function of the angular separation of the particles within a pair. They are sensitive to a multitude of perturbative and nonperturbative quantum chromodynamics phenomena in high-energy particle collisions. Using lead-lead data recorded with the CMS detector, energy-energy correlators inside high transverse momentum jets are measured in heavy ion collisions for the first time. The data are obtained at a nucleon-nucleon center-of-mass energy of 5.02 TeV and correspond to an integrated luminosity of 1.70 nb −1 . A similar analysis is done for proton-proton collisions at the same center-of-mass energy to establish a reference. The ratio of lead-lead to proton-proton energy-energy correlators reveals significant jet substructure modifications in the quark-gluon plasma. The results are compared to different models that incorporate either color coherence or medium response effects, where the two effects predict similar substructure modifications.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Dexmedetomidine preconditioning ameliorates lung injury induced by pulmonary ischemia/reperfusion by upregulating promoter histone H3K4me3 modification of KGF-2

Highlights: • DexP alleviates I/R-induced lung injury and endothelial barrier dysfunction in mice. • DexP reduces the inflammatory response and increases KGF-2 expression in I/R. • DexP regulates the H3K4me3 modification of KGF-2 promoter histone. • DexP promotes KGF-2 expression by downregulating the expression of JMJD3. • DexP has the potential to be used as a means of treating I/R-induced lung injury. Keratinocyte growth factor (KGF)-2 has been highlighted to play a significant role in maintaining the endothelial barrier integrity in lung injury induced by ischemia-reperfusion (I/R). However, the underlying mechanism remains largely unknown. The aims of this study were to determine whether dexmedetomidine preconditioning (DexP) modulates pulmonary I/R-induced lung injury through the alteration in KGF-2 expression. In our I/R-modeled mice, DexP significantly inhibited pathological injury, inflammatory response, and inflammatory cell infiltration, while promoted endothelial barrier integrity and KGF-2 promoter activity in lung tissues. Bioinformatics prediction and ChIP-seq revealed that I/R significantly diminished the level of H3K4me3 modification in the KGF-2 promoter, which was significantly reversed by DexP. Moreover, DexP inhibited the expression of histone demethylase JMJD3, which in turn promoted the expression of KGF-2. In addition, overexpression of JMJD3 weakened the protective effect of DexP on lung injury in mice with I/R. Collectively, the present results demonstrated that DexP ameliorates endothelial barrier dysfunction via the JMJD3/KGF-2 axis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Phosphoproteomics Modifications in Women with Rheumatoid Arthritis─Application of Web-Based Software to Enhance Data Visualization

Individuals with rheumatoid arthritis (RA) are at increased risk of functional disability, cardiovascular disease, and obesity, all of which are influenced by dysregulated skeletal muscle. Here, this pilot study aims to identify phosphoproteomics changes in RA skeletal muscle and visualize modifications through development of a web-based app designed to promote user-friendly data interpretation and visualization. NanoLC–MS/MS analysis was performed on vastus lateralis biopsies from three women with RA and matched healthy controls. Differential analysis was performed using the Limma R package. Kinase substrate enrichment analysis (KSEA) predicted changes in kinase activity. RA muscle displayed 35 upregulated and 60 downregulated phosphosites, including the cytoskeletal proteins TTN (Ser33201, Ser33013, Ser20925), NEB (Ser2219, Thr254, Ser33013, Ser20925), FLNA (Ser1459), and LASP1 (Ser146). Compared to healthy controls, KSEA predicted decreased activity of several kinases in RA muscle, including PRKACA and CDKs. All such changes were visualized by use of our web-based app. Overall, phosphoproteome analysis reveals signaling alterations in RA skeletal muscle linked to cytoskeletal proteins, representing candidate disease biomarkers; these modifications can be explored through use of our web-based software.

phosphoproteomics↗
DOE OSTI2021

Observation of the modification of quantum statistics of plasmonic systems

Abstract For almost two decades, researchers have observed the preservation of the quantum statistical properties of bosons in a large variety of plasmonic systems. In addition, the possibility of preserving nonclassical correlations in light-matter interactions mediated by scattering among photons and plasmons stimulated the idea of the conservation of quantum statistics in plasmonic systems. It has also been assumed that similar dynamics underlie the conservation of the quantum fluctuations that define the nature of light sources. So far, plasmonic experiments have been performed in nanoscale systems in which complex multiparticle interactions are restrained. Here, we demonstrate that the quantum statistics of multiparticle systems are not always preserved in plasmonic platforms and report the observation of their modification. Moreover, we show that optical near fields provide additional scattering paths that can induce complex multiparticle interactions. Remarkably, the resulting multiparticle dynamics can, in turn, lead to the modification of the excitation mode of plasmonic systems. These observations are validated through the quantum theory of optical coherence for single- and multi-mode plasmonic systems. Our findings unveil the possibility of using multiparticle scattering to perform exquisite control of quantum plasmonic systems.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Structural modification of fentanyls for their retrospective identification by gas chromatographic analysis using chloroformate chemistry

Abstract The one-step breakdown and derivatization of a panel of nine fentanyls to yield uniquely tagged products that can be detected by Electron Ionization Gas Chromatography-Mass Spectrometry (EI-GC-MS) is presented. The method involves the treatment of the synthetic opioids with 2,2,2-trichloroethoxycarbonyl chloride (TrocCl) at 60 °C for 3 h in dichloromethane and furnishes two products from one fentanyl molecule that can be used to retrospectively identify the original opioid. Parameters that were studied and fully optimized for the method included temperature, solvent, nature of scavenging base and reaction time. One of the two resulting products from the reaction bears the trichloroethoxycarbonyl (Troc) tag attached to the norfentanyl portion of the original opioid and greatly aids in the opioid detection and identification process. The methodology has been applied to the chemical modification of a panel of nine fentanyls and in all cases the molecular ion peak for the Troc-norfentanyl product bearing the distinctive trichloroethyl isotopic signature can be clearly observed. The method’s LLOD was determined to be 10 ng/mL while its LLOQ was found to be 20 ng/mL. This methodology represents the first application of chloroformates in the chemical modification of this class of synthetic opioids that are notoriously inert to common derivatization strategies available for GC–MS analysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Unusual electrical conductivity driven by localized stoichiometry modification at vertical epitaxial interfaces

Precise control of lattice mismatch accommodation and interfacial cation diffusion is critical to modulate correlated functionalities in epitaxial heterostructures, particularly when the interface composition is positioned near a compositional phase transition boundary. Here we select La 1-x Sr x MnO 3 (LSMO) as a prototype phase transition oxide and establish vertical epitaxial interfaces with NiO for exploring the strong interplay between strain accommodation, stoichiometry modification, and localized electron transport across the interface. It is found that localized stoichiometry modification overcomes the dead layer problem plaguing LSMO and leads to strongly directional conductivity, as manifested by a more than three orders of magnitude difference between out-of-plane and in-plane conductivity. Comprehensive atomic scale structural characterization and transport measurements reveal that this emerging behavior is created by a compositional change produced by preferential cation diffusion that pushes the LSMO phase transition from insulating into metallic within an ultrathin interface region. This study explores the nature of unusual electrical conductivity at vertical epitaxial interfaces and highlights the beneficial role of controllable cation diffusion that enables emerging functionalities for a broad range of potential applications such as memristors, spintronic devices, and novel nanoelectronic devices using strongly correlated materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Post-polymerization modification of polymethacrylates enabled by keto–enol tautomerization

We report a post-polymerization modification strategy to functionalize methacrylic copolymers through enol-ester transesterification. A new monomer, vinyl methacryloxy acetate (VMAc), containing both enol-ester and methacryloyl functionality, was successfully copolymerized with methyl methacrylate (MMA) by selective reversible addition–fragmentation chain transfer (RAFT) polymerization. Post-polymerization modification of pendent enol esters proceeded through an “irreversible” transesterification process, driven by the low nucleophilicity of the tautomerization product, to result in high conversion under mild conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Enabling electrochemical N 2 reduction to NH 3 in the low overpotential region using non-noble metal Bi electrodes via surface composition modification

The electrochemical N 2 reduction reaction (ENRR) that can produce NH 3 using water as the hydrogen source at ambient temperature and pressure can be an exciting alternative to the Haber–Bosch process. The major challenge for electrochemical NH 3 production is the competing hydrogen evolution reaction (HER), which seriously limits the faradaic efficiency (FE) for NH 3 production. To date, noble metal electrocatalysts that are inactive for the HER have mainly been investigated for the ENRR. Studies reporting a FE greater than 10% for NH 3 production using non-noble metal catalysts in the low overpotential region (E ≤ 0.2 V vs. RHE) are very rare. This study reports effective electrochemical surface modification strategies that drastically increase the ENRR activity of a non-noble Bi electrode in the low overpotential region and achieve a FE for NH 3 production as high as 13.2% at -0.2 V vs. RHE in pH 7.5 phosphate buffer. Finally, the effect of each of the surface modifications on the activity for the ENRR and the electrode stability during the ENRR were systematically elucidated, which may be used to develop general strategies to enhance the ENRR activities of other non-noble metal electrodes in the low overpotential region.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Enhanced charge carrier extraction and transport with interface modification for efficient tin-based perovskite solar cells

Interface modification improves charge carrier extraction in tin-based perovskite solar cells. Tin-based perovskites have become the most promising non-lead perovskites due to their ideal band gap and low toxicity. Although the open circuit voltage of tin-based perovskite solar cells (TPSCs) continues to approach the theoretical value, the short-circuit current is still far from the theoretical value. Here, we describe an interface modification method by regulating the property of hole transport layer, PEDOT:PSS, which improves the surface molecular morphology and the energy level alignment of PEDOT:PSS/perovskite interface. Advanced GIWAXS and IR s-SNOM characterization are conducted to achieve multi-dimensional characterization of nanoscale surface morphology and chemical distribution of PEDOT:PSS. With the multi-attribute optimization, charge carrier extraction and non-radiative recombination are also improved. The resultant TPSCs exhibit a higher power conversion efficiency of 13.32% in compared with the control device of 10.50%, accompanied with an increase in the short-circuit current from 18.10 to 20.50 mA cm −2 and FF from 68.23% to 76.43%. This work demonstrates a reliable strategy for improving charge carrier extraction and device performance for lead-free TPSCs.

Zhao, Zhenzhu↗
DOE OSTI2025

Support modification by phosphonic acid ligands controls ethylene hydroformylation on single-atom rhodium sites

To investigate the ability of surface-bound ligands to control activity toward ethylene hydroformylation, we modified site-isolated Rh 1 /TiO 2 with a series of substituted benzyl phosphonic acids. We found that modification of the support by phosphonic acids reduced break-in times for hydroformylation by 4× and increased absolute hydroformylation activity by up to 18× compared to unmodified catalyst at 150 °C. All functionalized catalysts improved hydroformylation activity by at least 9× and improved selectivity by between 7× and 60× relative to the unmodified catalyst. Carbon monoxide probe–molecule spectroscopy indicated that the enhancements in activity among modified samples were due to changes in the local environment of the active Rh site. Specifically, the bite angle of adsorbed carbon monoxide, as determined from infrared spectra, correlated with hydroformylation activity. These findings demonstrate that Rh 1 active sites are highly sensitive to modification of the support with organic ligands.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Organo-catalyzed deamination of polystyrene sulfonamide for diverse post-polymerization modification of styrenic polymers

Post-polymerization modification allows for the incorporation of functional groups that would otherwise be incompatible with polymerization conditions, enhancing synthetic efficiency and facilitating the creation of complex polymer architectures for specialized applications, such as biomedical devices, electronics, and advanced coatings. Herein, we report a method inspired by late-stage functionalization of small molecules for the post-polymerization modification of aromatic polymers, specifically polystyrene (PS), under mild reaction conditions. First, PS was converted to polystyrene sulfonamide (PSSNH 2 ) with an 85% yield using established procedures. PSSNH 2 was subsequently transformed into a reactive sulfinate by deamination using an N-heterocyclic carbene (NHC) catalyst and benzaldehyde. The catalytic process was optimized by varying catalysts, solvents, bases, temperatures, and reaction times. The highest degree of deamination was 88% with a bicyclic NHC and K 2 CO 3 base in DMSO for 18 hours at 120 °C. The reactive sulfinate was then treated with various functional reagents, resulting in a library of aromatic polymers with different substituents with high degrees of functionalization ranging from 74% to 98%. Similarly, we modified expanded PS waste with trifluorobutyl iodide with a degree of functionalization of 72%, highlighting a new avenue for plastic upgrading. This approach could be used to rapidly generate functionalized polymers from PS with potential applications, including antibacterial properties and flame retardancy.

Shrestha, Tulaja [Univ. of Delaware, Newark, DE (U↗