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At least 199 records · Page 11

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NASA NTRS1987

Atmospheric H2O2 measurement: comparison of cold trap method with impinger bubbling method

Collection of atmospheric H2O2 was performed by a cold trap method using dry ice-acetone as the refrigerant. The air was drawn by a pump into a glass gas trap immersed in the dry ice-acetone slush in a dewar flask at a flow rate of 2.5 l min-1 for approximately 2 h. Collection efficiency was > 99% and negligible interferences by O3, SO2 or organic matter with the collected H2O2 in the trap were observed. This method was compared with the air impinger bubbling method which has been previously described (Kok et al., 1978a, b, Envir. Sci. Technol. 12, 1072-1080). The measured total peroxide (H2O2 + organic peroxide) values in a series of aim samples collected by the impinger bubbling method (0.06-3.7 ppb) were always higher than those obtained by the cold trap method (0.02-1.2 ppb). Laboratory experiments suggest that the difference in values between the two methods probably results from the aqueous phase generation of H2O2 and organic peroxide in the impinger solution by a reaction of atmospheric O3 with olefinic and aromatic compounds. If these O3-organic compound reactions which occur in the impinger also occur in aqueous droplets in the atmosphere, the process could be very important for aqueous phase generation of H2O2 in clouds and rainwater.

NASA Discipline Exobiology↗

NASA NTRS2003

In Situ Remediation of Polychlorinated Bephenyls Using Palladium Coated Iron or Magnesium

The remediation of polychlorinated biphenyls (PCBs) and other chlorinated synthetic aromatic compounds are of great concern due to their toxicity and persistence in the environment. When released into the environment, PCBs are sorbed to particulate matter that can then disperse over large areas. Although the US Environmental Protection Agency (EPA) has banned the manufacture of PCBs since 1979, they are still present in the environment posing possible adverse health affects to both humans and animals. Thus, it is of utmost importance to develop a method that remediates PCB-contaminated soil, sediments, and water. The objective of our research was to develop an in-situ PCB remediation technique that is applicable for the treatment of soils and sediments. Previous research conducted at the University of Central Florida (UCF) proved the feasibility of using an emulsified system to dehalogenate a dense non-aqueous phase liquid (DNAPL) source, such as TCE, in the subsurface by means of an in-situ injection. The generation of a hydrophobic emulsion system drew the DNAPL TCE, through the oil membrane where it diffused to the iron particle and underwent degradation. TCE continued to enter, diffuse, degrade and exit the droplet maintaining a concentration gradient across the membrane, thus maintaining the driving force of the reaction.

Geiger, Cherie L.↗

NASA NTRS2004

Vibrational Spectroscopy at Cryogenic Temperatures: From the Laboratory to the Ends of the Universe

Polycyclic aromatic compounds (PAC) have been the subject of astrophysical interest for nearly two decades. Indeed, there is now evidence that these compounds are among the most abundant interstellar molecules, comprising perhaps 10 - 30% of all the carbon in our galaxy. Ranging in size from as few as 20 to as many as hundreds or thousands of carbon atoms, these molecules are enormous by interstellar standards and impact a wide range of astrophysical phenomena including: the near- and mid-infrared emission spectrum of a wide range of astronomical objects; the ultraviolet/visible/near-infrared absorption of the diffuse medium that permeates our galaxy; and the heating and cooling mechanisms of interstellar clouds. Nevertheless, until recently a lack of laboratory spectroscopic data on PAC under astrophysically relevant conditions (i.e. isolated, ionized molecules; ionized molecular clusters, etc.) has hindered critical evaluation and extension of this model. Fortunately, the last decade has seen an explosion of experimental and theoretical techniques aimed specifically at addressing these issues. Here, we begin with a brief review of the evidence for the existence and abundance of interstellar PAC. From there, we move on to an overview of the general spectroscopic characteristics of the range of isolated, neutral and ionized PAC that we have studied over the last decade. Finally, we will conclude with a consideration of the astrophysical implications and applications of interstellar PAC. Our discussion will revolve primarily around the observed interstellar infrared emission spectra and the ability of the laboratory spectra of varying combinations of PAC to accommodate both the global appearance and the region-to-region variability of this emission. Careful models based on sound laboratory spectroscopic data such as these now have the potential to provide insight into the structure, abundance, and ionization state of the interstellar PAC population. That, in turn, will provide direct insight into the processes of carbon nucleation, growth and evolution as matter is processed through the interstellar medium.

Hudgins, Douglas M.↗

NASA NTRS2006

Contaminant Removal From Natural Resources

A zero-valent metal emulsion containing zero-valent metal particles is used to remediate contaminated natural resources, such as groundwater and soil. In a preferred embodiment, the zero-valent metal emulsion removes heavy metals, such as lead (pb), from contaminated natural resources. In another preferred embodiment, the zero-valent metal emulsion is a bimetallic emulsion containing zero-valent metal particles doped with a catalytic metal to remediate halogenated aromatic compounds, such as polychlorinated biphenyls (PCBs), from natural resources.

Clausen, Christian A.↗

NASA NTRS2006

A Novel Method for Remediation of PCBs in Weathered Coatings

Polychlorinated biphenyls (PCBs) are a group of synthetic aromatic compounds with the general formula C 12H1oCl that were historically used in industrial paints, caulking material and adhesives, as their properties enhanced structural integrity, reduced flammability and boosted antifungal properties. Although the United States Environmental Protection Agency (USEPA) has banned the manufacture of PCBs since 1979, they have been found in at least 500 of the 1,598 National Priorities List (Superfund) sites identified by the USEPA. Prior to the USEPA's ban on PCB production, PCBs were commonly used as additives in paints and asphalt-based adhesives that were subsequently applied to a variety of structures. Government facilities constructed as early as 1930 utilized PCB-containing binders or PCB-containing paints, which are now leaching into the environment and posing ecological and worker health concerns. To date, no definitive in situ, non-destructive method is available for the removal of PCBs found in weathered coatings or on painted structures/equipment. The research described in this paper involves the laboratory development and field-scale deployment of a new and innovative solution for the removal and destruction of PCBs found in painted structures or within the binding or caulking material on structures. The technology incorporates a Bimetallic Treatment System (BTS) that extracts and degrades only the PCBs found on the facilities, leaving the structure virtually unaltered.

Brooks, Kathleen B.↗

NASA NTRS2006

The Ability of AMSTAR Dechlorination Solution to Remove and Degrade PCBs from Contaminated Surfaces

Polychlorinated biphenyls (PCBs) are a group of synthetic aromatic compounds with the general formula C12H(10-x)Cl(-x) that were historically used in industrial paints, caulking material and adhesives, as their properties enhanced structural integrity, reduced flammability and boosted antifungal properties. Although the United States Environmental Protection Agency (USEPA) has banned the manufacture of PCBs since 1979, they have been found in at least 500 of the 1,598 National Priorities List (Superfund) sites identified by the USEPA. Prior to the US EPA's ban on PCB production, PCBs were commonly used as additives in paints and asphalt-based adhesives that were subsequently applied to a variety of structures. Government facilities constructed as early as 1930 utilized PCB-containing binders or PCB-containing paints, which are now leaching into the environment and posing ecological and worker health concerns. In 2006, a commercially available product known as AMSTAR Dechlorination Solution was tested at NASA's Kennedy Space Center for its ability to remove and degrade PCBs from structural materials. This evaluation was requested by the Environmental Security Technology Certification Program (ESTCP) evaluating the ability of NASA's Bimetallic Treatment System (BTS) to remove and degrade PCBs from structural materials. The results of the laboratory testing are to be used to determine if a side-by-side field-scale test comparing BTS to AMSTAR was warranted. A recommended sampling and analysis testing program was submitted to ESTCP that included triplicate screening of AMSTAR's PCB dechlorination capabilities on a variety of surfaces including glass, bare metal, and painted metal coupons. The test procedures, analytical techniques and results obtained are presented in this interim report to ESTCP.

Quinn, Jacqueline E.↗

NASA NTRS2015

Interstellar and Solar System Organic Matter Preserved in Interplanetary Dust

Interplanetary dust particles (IDPs) collected in the Earth's stratosphere derive from collisions among asteroids and by the disruption and outgassing of short‐period comets. Chondritic porous (CP) IDPs are among the most primitive Solar System materials. CP‐IDPs have been linked to cometary parent bodies by their mineralogy, textures, C‐content, and dynamical histories. CP‐IDPs are fragile, fine‐grained (less than um) assemblages of anhydrous amorphous and crystalline silicates, oxides and sulfides bound together by abundant carbonaceous material. Ancient silicate, oxide, and SiC stardust grains exhibiting highly anomalous isotopic compositions are abundant in CP‐IDPs, constituting 0.01 - 1 % of the mass of the particles. The organic matter in CP‐IDPs is isotopically anomalous, with enrichments in D/H reaching 50x the terrestrial SMOW value and 15N/14N ratios up to 3x terrestrial standard compositions. These anomalies are indicative of low T (10‐100 K) mass fractionation in cold molecular cloud or the outermost reaches of the protosolar disk. The organic matter shows distinct morphologies, including sub‐um globules, bubbly textures, featureless, and with mineral inclusions. Infrared spectroscopy and mass spectrometry studies of organic matter in IDPs reveals diverse species including aliphatic and aromatic compounds. The organic matter with the highest isotopic anomalies appears to be richer in aliphatic compounds. These materials also bear similarities and differences with primitive, isotopically anomalous organic matter in carbonaceous chondrite meteorites. The diversity of the organic chemistry, morphology, and isotopic properties in IDPs and meteorites reflects variable preservation of interstellar/primordial components and Solar System processing. One unifying feature is the presence of sub‐um isotopically anomalous organic globules among all primitive materials, including IDPs, meteorites, and comet Wild‐2 samples returned by the Stardust mission.

Messenger, Scott↗

NASA NTRSDate not supplied

Time Resolved Visualization of A Liquid Jet in an RDE Using MHz Rate Diesel PLIF

The characterization of the dynamic response of liquid jets to transient detonation wave passage is critical for optimization and modeling of liquid fueled rotating detonation combustors. In this work, a rotating detonation combustor (RDC) is operated on hydrogen and air to sustain stable detonation waves that acts as a detonation driver and interact in a one-way coupled manner with a single liquid fuel jet that propagates into the combustion chamber with cycle periods of ~ 250 μs. Diesel is utilized as a realistic fuel surrogate with higher aromatic compounds to enable fluorescence excitation, using the 355 nm third harmonic output of a burst-mode Nd:YAG laser, imaged at rates up to 1 MHz. By optimizing the technique to accommodate orders of magnitude variations in the fuel density throughout the injection process, the PLIF data enable quantitative measurements including the refill time, the relative recovery between liquid and gaseous jets and jet trajectory across various momentum flux ratio. As the passage of the detonation wave imparts significant changes in the momentum flux ratio, the qualitative liquid break-up process and spatial distribution varies significantly in time. As the injection system recovers ~ 70% of the cycle period and return to a quasi-steady position and allow comparisons with theoretical jet trajectories. These data, enabled by ultra-high-speed PLIF imaging, represent some of the first detailed measurements for quantifying the dynamic response and recovery of liquid jets exposed to periodic detonations in an operating RDC.

Propulsion↗

NASA NTRSDate not supplied

Time Resolved Visualization of Liquid Jet Interaction With H2-Air Rotating Detonations Using MHz Rate Diesel PLIF

The characterization of the dynamic response of liquid jets to transient detonation wave passage is critical for optimization and modeling of liquid fueled rotating detonation combustors. In this work, a rotating detonation combustor (RDC) is operated on hydrogen and air to sustain stable detonation waves that acts as a detonation driver and interact in a one-way coupled manner with a single liquid fuel jet that propagates into the combustion chamber with cycle periods of ~ 250 μs. Diesel is utilized as a realistic fuel surrogate with higher aromatic compounds to enable fluorescence excitation, using the 355 nm thirdharmonic output of a burst-mode Nd:YAG laser, imaged at rates up to 1 MHz. By optimizing the technique to accommodate orders of magnitude variations in the fuel density throughout the injection process, the PLIF data enable quantitative measurements including the refill time, the relative recovery between liquid and gaseous jets and jet trajectory across various momentum flux ratio. As the passage of the detonation wave imparts significant changes in the momentum flux ratio, the qualitative liquid break-up process and spatial distribution varies significantly in time. As the injection system recovers ~ 70% of the cycle period and return to a quasi-steady position and allow comparisons with theoretical jet trajectories. These data, enabled by ultra-high-speed PLIF imaging, represent some of the first detailed measurements for quantifying the dynamic response and recovery of liquid jets exposed to periodic detonations in an operating RDC.

Propulsion↗

NASA NTRSDate not supplied

Formation of Insoluble Organic Material from the Ultraviolet Irradiation of Laboratory Ice Photolysis Residues

We present preliminary results from the study of ice photolysis residues which were exposed to ultraviolet (UV)/extreme UV (EUV) photon radiation. The residues were produced from the simultaneous deposition and UV irradiation of ice mixtures of astrophysical interest (H2O, CH3OH, CO, NH3, without/with N2 and/or O2, and without/with small quantities of aromatic compounds) at 15–20 K using an H2 lamp, which emits 10.2-eV (121.6 nm) Lyman-α photons and a continuum at 7.5–8 eV (155–165 nm). After warm-up to room temperature and subsequent sublimation of volatile compounds, the refractory materials (residues) recovered at room temperature were analyzed with infrared (IR) microscopy and then further irradiated with UV/EUV photons at a synchrotron facility, on a beamline providing a broad-band photon beam in the 4–45-eV range with a ~1016 photons s-1 flux.2 The residues were UV/EUV irradiated with increasing photon doses ranging from ~1018 to ~1021 photons, i.e., covering 4 orders of magnitude and relevant to those experienced by ice-coated grains in the protosolar nebula.1. After UV/EUV irradiation, residues were analyzed with IR microscopy and the data compared to those before irradiation to identify changes in chemical composition as a function of the photon dose. UV/EUV-irradiated residues were also analyzed with other techniques such as nanoscale secondary-ion mass spectrometry (nanoSIMS) to the study the changes in isotopic composition, and scanning transmission electron microscopy to look at variations in structure and C bonding distribution. Results will be compared with data from extraterrestrial materials, in particular, meteoritic insoluble organic material (IOM) and interplanetary dust particles (IDPs).

Ices↗

DOE OSTI2020

Catalysts and process for liquid hydrocarbon fuel production

The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

White, Mark G.↗

DOE OSTI2022

Performance Advantaged ..beta..-Ketone Containing Polymers - Benefits in Manufacturing, Performance, and End-of-Life

Biomass derived chemicals can possess extended functionality, often in the form of heteroatoms like oxygen and nitrogen, that can enable performance advantaged properties in emergent materials. These performance advantages can manifest in multiple ways such as reduced manufacturing intensity, better performance, or enhanced end-of-life options. One illustrative example of this concept is ..beta..-ketoadipic acid (..beta..KA), a C6 dicarboxylic acid with a ketone in its backbone. ..beta..KA can be obtained via biological cultivation from aromatic compounds, sugars, and even waste plastics. When ..beta..KA is implemented into polymers, namely nylons, in place of adipic acid the overall material properties are increased. Specifically, the glass transition temperature (which is the measurement at which temperature a plastic softens) is increased by 69 degrees C and the water permeability is reduced by 20%. Molecular dynamic (MD) simulations reveal that the ..beta..-ketone in ..beta..KA leads to restricted movement across multiple backbone carbons when compared to adipic acid. Furthermore, MD simulations reveal that the ..beta..-ketone, when compared to no-ketone or an a-ketone, can lead to an increase in hydrogen bonding between neighboring chains. Both phenomena may help explain the molecular origin of the increases in polymer performance. When implemented into polyesters, namely PET, ..beta..KA can maintain the requisite performance while enabling enhanced degradation. Aside from performance advantages in thermomechanical performance, the production of ..beta..KA also is advantaged in its manufacturing. Although estimates for the minimum selling price (MSP) of ..beta..KA exceed adipic acid the manufacture of ..beta..KAwould reduce supply chain energy and GHG emissions by >50% and >30% respectively. Further TEA analysis reveals that the MSP of ..beta..KA is primarily driven by the feedstock cost while the capital expenditures are driven largely by fermentation costs. Overall, the work presented within will be illustrative of how biomass derived molecules, namely ..beta..KA, can manifest performance advantages across multiple benchmarks and may enable a path to market for biomass-derived materials.

ADVANCED PROPULSION SYSTEMS,BIOMASS FUELS↗

DOE OSTI2022

..beta..-Ketoadipic Acid Production in P. putida for Performance-Advantaged Nylons

Biomass derived chemicals can possess extended functionality, often in the form of heteroatoms like oxygen and nitrogen, that can enable performance advantaged properties in emergent materials. One illustrative example of this concept is ..beta..-ketoadipic acid (..beta..KA), a C6 dicarboxylic acid with a ketone in its backbone. ..beta..KA can be obtained via biological cultivation from aromatic compounds, sugars, and even waste plastics. When ..beta..KA is implemented into polymers, namely nylons, in place of adipic acid the overall material properties are increased. Specifically, the glass transition temperature (which is the measurement at which temperature a plastic softens) is increased by 69 degrees C and the water permeability is reduced by 20%. Molecular dynamic (MD) simulations reveal that the ..beta..-ketone in ..beta..KA leads to restricted movement across multiple backbone carbons when compared to adipic acid. Furthermore, MD simulations reveal that the ..beta..-ketone, when compared to no-ketone or an a-ketone, can lead to an increase in hydrogen bonding between neighboring chains. Both phenomena may help explain the molecular origin of the increases in polymer performance. Aside from performance advantages in thermomechanical performance, the production of ..beta..KA also is advantaged in its manufacturing. Although estimates for the minimum selling price (MSP) of ..beta..KA exceed adipic acid the manufacture of ..beta..KA would reduce supply chain energy and GHG emissions by >50% and >30% respectively. Further TEA analysis reveals that the MSP of ..beta..KA is primarily driven by the feedstock cost while the capital expenditures are driven largely by fermentation costs. Overall, the work presented within will be illustrative of how biomass derived molecules, namely ..beta..KA, can manifest performance advantages across multiple benchmarks and may enable a path to market for biomass-derived materials.

beta-ketoadipic acid↗

DOE OSTI2022

In vitro methods of chemical conversion using non-stereospecific glutathione lyases

Enzymes for depolymerizing lignin. The enzymes include dehydrogenases, β-etherases, and glutathione lyases. The dehydrogenases can comprise one or more or LigD, LigO, LigN, and LigL. The β-etherases can comprise one or more of LigE, LigF, LigP, and BaeA. The glutathione lyases can comprise any one or more of LigG and a number of non-stereospecific, optionally recombinant glutathione lyases derived from Sphingobium sp. SYK-6, Novosphingobium aromaticivorans, Escherichia coli, Streptococcus sanguinis, Phanerochaete chrysosporium , and other microorganisms. The enzymes can be combined in compositions and/or used in methods of processing lignin or other aromatic compounds in vitro.

Donohue, Timothy James↗

DOE OSTI2023

Catalysts and process for liquid hydrocarbon fuel production

White, Mark G.↗

DOE OSTI2026

Catabolism of lignin-related methoxylated compounds in white-rot fungi utilizes non-canonical oxidoreductases

White-rot fungi (WRF) are the most effective lignin-degrading organisms in nature, making them essential to Earth’s carbon cycle. Lignin is a highly methoxylated, heterogeneous biopolymer derived from plants. However, the pathways WRF use to metabolize methoxylated aromatic monomericcompounds as carbon sources remain unidentified. Here, we employ a systems biology approach to elucidate the intracellular catabolism of vanillate – a monomethoxylated aromatic compound – in two white-rot fungi (WRF), Gelatoporia subvermispora and Trametes versicolor. We identified and biochemically validated a four-enzyme pathway that converts vanillate into ß-ketoadipate – a metabolite that enters central carbon metabolism. This pathway deviates from typical bacterial pathways, where vanillate is initially demethylated and ring-cleaved by intradiol dioxygenases; instead, oxidative decarboxylation occurs prior to ring cleavage by extradiol dioxygenases. Thus, we conducted an in-depth investigation of ring cleavage and further downstream catabolism by the identified fungal enzymes using biochemical and structural approaches. This revealed non-canonical enzymes, including a highly substrate-specific extradiol dioxygenase and a metal-free, promiscuous reductase, the latter capable of acting on catabolic intermediates derived from both methoxylated and non-methoxylated aromatic compounds. This work emphasizes the potential of WRF and their enzymes to advance lignin valorization and enhance our understanding of their role during wood decay.

dioxygenase↗

DOE OSTI2023

Systems Engineering of Rhodococcus opacus to Enable Production of Drop-in Fuels from Lignocellulose

Production of drop-in fuels from lignocellulose using Rhodococcus opacus PD630 (hereafter R. opacus) is a challenging goal. During the grant period we have pushed the field forward significantly in several areas of research. Towards the end goal of accelerating the adoption of R. opacus in biofuel production, during the grant period we have expanded the phenotypic characterization of R. opacus grown in single aromatic (model lignocellulosic) compounds or their mixtures, modeling the growth conditions in lignocellulosic biomass. Harnessing the power of adaptive evolution, we produced evolved R. opacus isolates with superior lignin valorization capabilities and identified differentially expressed genes and pathways after adaptation. We used next generation multi-omic techniques such as genomic, transcriptomic, and metabolomic analyses, to identify the catabolic pathways used by R. opacus to degrade aromatic compounds and funnel these degradation products into central metabolism, as well as the aromatic transport genes required for increased tolerance and utilization. Taking this information one step further, we identified endogenous transcription factors and regulatory mechanisms important for degradation of five model aromatic compounds. To accurately estimate R. opacus growth and consumption on model lignin compounds we pioneered the use of novel extraction procedures prior to GC-MS analysis. Alongside 13 C-metabolic flux analysis, we have elucidated the metabolic routes preferred by Rhodococcus opacus during aromatic compound degradation. Finally, we used in tandem lipidomics and high-resolution mass spectrometry to identify the modulation of mycolic acids and phospholipid membrane composition modification as a strategy for aromatic tolerance in R. opacus. Being a non-model organism, R. opacus lacks the breadth of tools and technical foundation which drive biofuel research in more well-understood microbes such as Escherichia coli. To reduce this burden for use, we designed and produced new tools for genomic manipulation and engineering in R. opacus. These engineering breakthroughs support efficient genomic editing, enabling gene overexpression, repression, and genetic alteration. Using these tools, we have generated synthetically engineered strains with increased lipogenesis and growth, both positive traits required for increased lignin valorization. Optimizing engineered strains for biofuel production from lignocellulose requires extremely sophisticated synthetic rewiring of metabolism. To facilitate systems-level reorganization of metabolism in R. opacus, we created a genome-scale model that accurately predicts metabolic flux and growth rates on the aromatic compound phenol. Lignin requires extensive pre-treatment before biological degradation by R. opacus. Towards an eventual goal of degrading real-world lignin, we developed new depolymerization processes to generate lignin breakdown products (LBP). We optimized LBP storage and composition analysis techniques, enabling accurate prediction of specific LBP compound integration into cell wall components. Overall, through the work funded by this grant we generated 20 manuscripts (17 published, 3 in review/preparation), methods for increased accuracy in metabolomics of aromatic compounds, multiple genetic tools for altering the R. opacus genome, genome scale models for predicting flux through metabolic pathways, as well as multi-omic data for community use. The work funded by this grant has increased the knowledge of aromatic degradation in bacteria and advanced our efforts to optimize R. opacus for lignin valorization.

09 BIOMASS FUELS↗

NASA NTRS1965

Organic compounds in carbonaceous chondrites.

Aromatic hydrocarbons in carbonaceous chondrites investigated by time-of-flight mass spectrometry and hypothesized as formed in solar nebula under thermodynamic equilibrium

AROMATIC COMPOUND↗