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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Enter TCM and Associated Equipment into Stage One Mockup

The scope of the FY17 milestone involved entering the TCM into stage one mockup at the Materials and Fuels Complex (MFC) and completing initial testing. While the TCM head was designed and partially fabricated in FY16, the ancillary equipment and software for standalone operation at the IMCL still required development. The tasks required to prepare the TCM for stage one mockup included: 1 – develop cell feedthroughs for both optical and electrical signals, 2 – design and construction of a film thickness monitor, 3 – drafting an equipment qualification plan, 4 – develop an integrated equipment rack to house lasers and instrumentation, and 5 – develop coding instrumentation software for controlling the TCM.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Synthesis and Characterization of a Novel pH-Sensitive Aluminum Crosslinked Carboxymethyl Tragacanth Beads for Extended and Enteric Drug Delivery

Carboxymethyl tragacanth (CM-TG) with a DS of 1.2 was synthesized and characterized for drug delivery using diclofenac sodium as a model drug. The mixture of CM-TG and drug was ionically crosslinked using aluminum chloride to form drug-loaded beads. The concentrations of 10 and 20% w/w solution of CM-TG were found to produce beads with acceptable qualities. The beads exhibited pH-dependent swelling. The highest swelling was observed at pH 6.8 which evidences the possibility to release the drug in the colon. FT-IR and TGA confirmed carboxymethylation of tragacanth and the absence of drug-polymer interaction. The diclofenac sodium entrapment efficiency was 30–35% while the loading varies from 4.5 to 18% w/w based upon the drug-polymer ratio. The beads could extend the drug release up to 180 min at pH 6.8. The pH-responsive CM-TG hydrogel beads are biocompatible and could be exploited as a new excipient in developing enteric release formulations.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Decreased proliferative, migrative and neuro-differentiative potential of postnatal rat enteric neural crest-derived cells during culture in vitro

A growing body of evidence supports the potential use of enteric neural crest-derived cells (ENCCs) as a cell replacement therapy for Hirschsprung's disease. Based on previous observations of robust propagation of primary ENCCs, as opposed to their progeny, it is suggested that their therapeutic potential after in vitro expansion may be restricted. We therefore examined the growth and differentiation activities and phenotypic characteristics of continuous ENCC cultures. ENCCs were isolated from the intestines of postnatal rats and were identified using an immunocytochemical approach. During continuous ENCC culture expansion, proliferation, migration, apoptosis, and differentiation potentials were monitored. The Cell Counting Kit-8 was used for assessment of ENCC vitality, Transwell inserts for cell migration, immunocytochemistry for cell counts and identification, and flow cytometry for apoptosis. Over six continuous generations, ENCC proliferation potency was reduced and with prolonged culture, the ratio of migratory ENCCs was decreased. The percentage of apoptosis showed an upward trend with prolonged intragenerational culture, but showed a downward trend with prolonged culture of combined generations. Furthermore, the percentage of peripherin{sup +} cells decreased whilst the percentage of GFAP{sup +} cells increased with age. The results demonstrated that alterations in ENCC growth characteristics occur with increased culture time, which may partially account for the poor results of proposed cell therapies. - Highlights: • Differences were identified between primary and daughter ENCCs. • Daughter ENCCs had reduced proliferation, migration and differentiation. • Daughter ENCCs also had increased apoptosis. • These altered characteristics warrant further investigation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Combination of exogenous cell transplantation and 5-HT{sub 4} receptor agonism induce endogenous enteric neural crest-derived cells in a rat hypoganglionosis model

Enteric neural crest-derived cells (ENCCs) can migrate into endogenous ganglia and differentiate into progeny cells, and have even partially rescued bowel function; however, poor reliability and limited functional recovery after ENCC transplantation have yet to be addressed. Here, we investigated the induction of endogenous ENCCs by combining exogenous ENCC transplantation with a 5-HT{sub 4} receptor agonist mosapride in a rat model of hypoganglionosis, established by benzalkonium chloride treatment. ENCCs, isolated from the gut of newborn rats, were labeled with a lentiviral eGFP reporter. ENCCs and rats were treated with the 5-HT{sub 4} receptor agonist/antagonist. The labeled ENCCs were then transplanted into the muscular layer of benzalkonium chloride-treated colons. At given days post-intervention, colonic tissue samples were removed for histological analysis. ENCCs and neurons were detected by eGFP expression and immunoreactivity to p75{sup NTR} and peripherin, respectively. eGFP-positive ENCCs and neurons could survive and maintain levels of fluorescence after transplantation. With longer times post-intervention, the number of peripherin-positive cells gradually increased in all groups. Significantly more peripherin-positive cells were found following ENCCs plus mosapride treatment, compared with the other groups. These results show that exogenous ENCCs combined with the 5-HT{sub 4} receptor agonist effectively induced endogenous ENCCs proliferation and differentiation in a rat hypoganglionosis model. - Highlights: • Survival and differentiation of exogenous ENCCs in treated colons. • With longer times post-intervention, the number of ENCCs and their progeny cells gradually increased. • Exogenous ENCCs combined with the 5-HT4 receptor agonist ffectively induced ENCCs proliferation and differentiation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Thermally Significant Fluid Seepage Through Thick Sediment on the Juan de Fuca Plate Entering the Cascadia Subduction Zone

We use heat flux measurements colocated with seismic reflection profiles over a buried basement high on the Juan de Fuca plate ∼25 km seaward of the deformation front offshore Oregon to test for the presence of hydrothermal circulation in the oceanic crust. We also revisit heat flux data crossing a buried basement high ∼25 km seaward of the deformation front ∼150 km north, offshore Washington. Seafloor heat flux is inversely correlated with sediment thickness, consistent with vigorous hydrothermal circulation in the basement aquifer homogenizing temperatures at the top of the basement. Heat flux immediately above the summit of the basement highs is greater than expected solely from conduction. Fluid seepage at rates of ∼2.6–5.4 cm yr −1 in a 1–1.5 km-wide conduit through ∼800–1,300 m thick sediment sections above these basement highs can explain these observations. Observations of thermally significant fluid seepage through sediment >225 m thick on oceanic crust are unprecedented. High sediment permeability, high fluid overpressure in the basement, or a combination of both is required to drive fluid seepage at the observed rates. We infer that rapid seepage occurs because the basement highs rise above the low permeability basal sediment with their tops protruding into the base of high permeability Nitinat or Astoria Fan sediment. Seepage from basement highs penetrating into the submarine fans can affect the thermal state of crust entering the subduction zone.

58 GEOSCIENCES↗
DOE OSTI2024

Genotypic analyses of IncHI2 plasmids from enteric bacteria

Incompatibility (Inc) HI2 plasmids are large (typically > 200 kb), transmissible plasmids that encode antimicrobial resistance (AMR), heavy metal resistance (HMR) and disinfectants/biocide resistance (DBR). To better understand the distribution and diversity of resistance-encoding genes among IncHI2 plasmids, computational approaches were used to evaluate resistance and transfer-associated genes among the plasmids. Complete IncHI2 plasmid (N - 667) sequences were extracted from GenBank and analyzed using AMRFinderPlus, IntegronFinder and Plasmid Transfer Factor database. The most common IncHI2-carrying genera included Enterobacter (N = 209), Escherichia (N = 208), and Salmonella (N = 204). Resistance genes distribution was diverse, with plasmids from Escherichia and Salmonella showing general similarity in comparison to Enterobacter and other taxa, which grouped together. Plasmids from Enterobacter and other taxa had a higher prevalence of multiple mercury resistance genes and arsenic resistance gene, arsC, compared to Escherichia and Salmonella. For sulfonamide resistance, sul1 was more common among Enterobacter and other taxa, compared to sul2 and sul3 for Escherichia and Salmonella. Similar gene diversity trends were also observed for tetracyclines, quinolones, β-lactams, and colistin. Over 99% of plasmids carried at least 25 IncHI2-associated conjugal transfer genes. These findings highlight the diversity and dissemination potential for resistance across different enteric bacteria and value of computational-based approaches for the resistance-gene assessment.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Disturbance of hibernating bats due to researchers entering caves to conduct hibernacula surveys

Estimating population changes of bats is important for their conservation. Population estimates of hibernating bats are often calculated by researchers entering hibernacula to count bats; however, the disturbance caused by these surveys can cause bats to arouse unnaturally, fly, and lose body mass. We conducted 17 hibernacula surveys in 9 caves from 2013 to 2018 and used acoustic detectors to document cave-exiting bats the night following our surveys. We predicted that cave-exiting flights (i.e., bats flying out and then back into caves) of Townsend’s big-eared bats (Corynorhinus townsendii) and western small-footed myotis (Myotis ciliolabrum) would be higher the night following hibernacula surveys than on nights following no surveys. Those two species, however, did not fly out of caves more than predicted the night following 82% of surveys. Nonetheless, the activity of bats flying out of caves following surveys was related to a disturbance factor (i.e., number of researchers × total time in a cave). We produced a parsimonious model for predicting the probability of Townsend’s big-eared bats flying out of caves as a function of disturbance factor and ambient temperature. That model can be used to help biologists plan for the number of researchers, and the length of time those individuals are in a cave to minimize disturbing bats.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Centrifugal sedimentation immunoassays for multiplexed detection of enteric bacteria in ground water

Water-born pathogens pose significant threat to the global population and early detection plays an important role both in making drinking water safe, as well as in diagnostics and treatment of water-borne diseases. We present an innovative centrifugal microfluidic platform (SpinDx) for detection of bacterial pathogens using bead-based immunoassays. Our approach is based on binding of pathogens to antibody-functionalized capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk and quantification by fluorescence microscopy. Our platform is fast (20 min), sensitive (10 3 CFU/mL), requires minimal sample preparation, and can detect multiple pathogens simultaneously with sensitivity similar to that required by the EPA. We demonstrate detection of a panel of enteric bacteria (Escherichia coli, Salmonella typhimurium, Shigella, Listeria, and Campylobacter) at concentrations as low as 10 3 CFU/mL or 30 bacteria per reaction.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Magnetization around mix jets entering inertial confinement fusion fuel

Engineering features are known to cause jets of ablator materials to enter the fuel hot-spot in inertial confinement fusion implosions. The Biermann battery mechanism wraps them in a self-generated magnetic field. Here we show that higher-Z jets have an additional thermoelectric magnetic source term that is not present for hydrogen jets, verified here through a kinetic simulation. It has similar magnitude to the Biermann term. We then include this in an extended magneto-hydrodynamic approach to post process an xRAGE radiation-hydrodynamic implosion simulation. The simulation includes an accurate model for the capsule fill tube, producing a dense carbon jet that becomes wrapped in a 4000 T magnetic field. A simple spherical carbon mix model shows that this insulates the electron heat conduction enough to cause contraction of the jet to an optically thick equilibrium. The denser magnetized jet hydrodynamics could change its core penetration and therefore the final mix mass, which is known to be well correlated with fusion yield degradation. Fully exploring this will require self-consistent magneto-hydrodynamic simulations. Experimental signatures of this self-magnetization may emerge in the high energy neutron spectrum.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Enhancing the Resistance of Spectral Characteristics of Interference Coatings to Deviation in Parameters of Layers Entering into Their Composition

A new method of enhancing the resistance of spectral characteristics of interference coatings to deviations in parameters of layers entering into their composition is presented. The spectral characteristic that can be obtained using this method for the energy transmittance (or reflectance) of an experimentally manufactured coating is maximally close to the characteristic of the synthesized coating. A way to use several samples for monitoring the thickness of layers during the process of their formation with the aim to reduce the deviation of optical layers during manufacturing of interference coatings is presented.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Enteric infection coupled with chronic Notch pathway inhibition alters colonic mucus composition leading to dysbiosis, barrier disruption and colitis

Intestinal mucus layer disruption and gut microflora modification in conjunction with tight junction (TJ) changes can increase colonic permeability that allows bacterial dissemination and intestinal and systemic disease. In a previous study, we showed that Citrobacter rodentium (CR)-induced colonic crypt hyperplasia and/or colitis is regulated by a functional cross-talk between the Notch and Wnt/β-catenin pathways. In the current study, mucus analysis in the colons of CR-infected (10 8 CFUs) and Notch blocker Dibenzazepine (DBZ, i.p.; 10μmol/Kg b.w.)-treated mice revealed significant alterations in the composition of trace O-glycans and complex type and hybrid N -glycans, compared to CR-infected mice alone that preceded/ accompanied alterations in 16S rDNA microbial community structure and elevated EUB338 staining. While mucin-degrading bacterium, Akkermansia muciniphila (A. muciniphila) along with Enterobacteriaceae belonging to Proteobacteria phyla increased in the feces, antimi- crobial peptides Angiogenin-4, Intelectin-1 and Intelectin-2, and ISC marker Dclk1, exhibited dramatic decreases in the colons of CR-infected/DBZ-treated mice. Also evident was a loss of TJ and adherens junction protein immuno-staining within the colonic crypts that negatively impacted paracellular barrier. These changes coincided with the loss of Notch signaling and exacerbation of mucosal injury. In response to a cocktail of antibiotics (Metro- nidazole/ciprofloxacin) for 10 days, there was increased survival that coincided with: i) decreased levels of Proteobacteria , ii) elevated Dclk1 levels in the crypt and, iii) reduced paracellular permeability. Thus, enteric infections that interfere with Notch activity may pro- mote mucosal dysbiosis that is preceded by changes in mucus composition. Controlled use of antibiotics seems to alleviate gut dysbiosis but may be insufficient to promote colonic crypt regeneration.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Detection of a Space Capsule Entering Earth’s Atmosphere with Distributed Acoustic Sensing (DAS)

On 24 September 2023, the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer sample return capsule (SRC) entered Earth’s atmosphere after successfully collecting samples from an asteroid. The known trajectory and timing of this return provided a rare opportunity to strategically instrument sites to record geophysical signals produced by the capsule because it travelled at hypersonic speeds through the atmosphere. For this work, we deployed two distributed acoustic sensing (DAS) interrogators to sample over 12 km of surface-draped fiber-optic cables, as well as six collocated seismometer-infrasound sensor pairs, spread across two sites near Eureka, Nevada. This campaign-style rapid deployment is the first reported recording of an SRC re-entry with any distributed fiber-optic sensing technology. The DAS interrogators recorded an impulsive arrival with an extended coda which had features that were similar to recordings from both the seismometers and infrasound sensors. While the signal-to-noise ratio of the DAS data was lower than the seismic-infrasound data, the extremely dense spacing of fiber-optic sensors allowed for more phases to be clearly distinguished and the visualization of the continuous transformation of the wavefront as it impacted the ground. Unexpectedly, the DAS recordings contain less low-frequency content than is present in both the seismic and infrasound data. The deployment conditions strongly affected the recorded DAS data; in particular, we observed that fiber selection and placement exert strong controls on data quality.

58 GEOSCIENCES↗
DOE OSTI2015

IV Administered Gadodiamide Enters the Lumen of the Prostatic Glands: X-Ray Fluorescence Microscopy Examination of a Mouse Model

In our objective, we descibe how dynamic contrast-enhanced MRI (DCE-MRI) has become a standard component of multiparametric protocols for MRI examination of the prostate, and its use is incorporated into current guidelines for prostate MRI examination. Analysis of DCE-MRI data for the prostate is usually based on the distribution of gadolinium-based agents, such as gadodiamide, into two well-mixed compartments, and it assumes that gadodiamide does not enter into the glandular lumen. However, this assumption has not been directly tested. The purpose of this study was to use x-ray fluorescence microscopy (XFM) imaging in situ to measure the concentration of gadodiamide in the epithelia and lumens of the prostate of healthy mice after IV injection of the contrast agent. For our materials and methods, six C57Bl6 male mice (age, 28 weeks) were sacrificed 10 minutes after IV injection of gadodiamide (0.13 mmol/kg), and three mice were sacrificed after saline injection. Prostate tissue samples obtained from each mouse were harvested and frozen; 7-μm-thick slices were sectioned for XFM imaging, and adjacent 5-μm-thick slices were sectioned for H and E staining. Elemental concentrations were determined from XFM images. Our results show mean (± SD) baseline concentration of gadolinium of 0.01 ± 0.01 mM was determined from XFM measurements of prostatic tissue samples when no gadodiamide was administered, and it was used to determine the measurement error. When gadodiamide was added, the mean concentrations of gadolinium in the epithelia and lumens in 32 prostatic glands from six mice were 1.00 ± 0.13 and 0.36 ± 0.09 mM, respectively. In conclusion, our data suggest that IV administration of gadodiamide results in uptake of contrast agent by the glandular lumens of the mouse prostate. We were able to quantitatively determine gadodiamide distributions in mouse prostatic epithelia and lumens.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Gender Gaps in Mode Usage, Vehicle Ownership, and Spatial Mobility When Entering Parenthood: A Life Course Perspective

Entry into parenthood is a major disruptive event to travel behavior, and gender gaps in mobility choices are often widened during parenthood. The exact timing of gender gap formation and their long-term effects on different subpopulations are less studied in the literature. Leveraging a longitudinal dataset from the 2018 WholeTraveler Study, this paper examines the effects of parenthood on a diverse set of short- to long-term outcomes related to the three hierarchical domains of mobility biography: mode choice, vehicle ownership, spatial mobility, and career decisions. The progress of the effects is evaluated over a sequential set of parenting stages and differentiated across three subpopulations. We find that individuals classified as “Have-it-alls”, who start their careers, partner up, and have children concurrently and early, significantly increase their car uses two years prior to childbirth (“nesting period”), and they then relocate to less transit-accessible areas and consequently reduce their reliance on public transportation while they have children in the household. In contrast, individuals categorized as “Couples”, who start careers and partnerships early but delay parenthood, and “Singles”, who postpone partnership and parenthood, have less pronounced changes in travel behavior throughout the parenting stages. The cohort-level effects are found to be driven primarily by women, whose career development is on average more negatively impacted by parenting events than men, regardless of their life course trajectory. Early career decisions made by women upon entering parenthood contribute to gender gaps in mid- to longer-term mobility decisions, signifying the importance of early intervention.

Yang, Hung-Chia (ORCID:0000000161439904)↗
DOE OSTI2020

The Preservation of Super-Earths and the Emergence of Gas Giants after Their Progenitor Cores Have Entered the Pebble-isolation Phase

The omnipresence of super-Earths suggests that they are able to be retained in natal disks around low-mass stars, whereas exoplanets' mass distributions indicate that some cores have transformed into gas giants through runaway gas accretion at ≳1 au from solar-type stars. In this paper, we show that transition to runaway gas accretion by cores may be self-impeded by an increase of the grain opacity in their envelope after they have acquired sufficient mass (typically ~ 10M ⊕ ) to enter a pebble-isolation phase. The accumulation of approximately millimeter- to meter-sized pebbles in their migration barriers enhances their local fragmentation rates. The freshly produced submillimeter grains pass through the barrier, elevate the effective dust opacity, and reduce the radiative flux in the core's envelope. These effects alone are adequate to suppress the transition to runaway accretion and preserve super-Earths in the stellar proximity (~0.1 au), albeit entropy advection between the envelope and the disk can further reduce the accretion rate. At an intermediate distance (~1 au) from their host stars, the escalation in the dust opacity dominates over entropy advection in stalling the transition to runaway accretion for marginally pebble-isolated cores. Beyond a few astronomical unit, the transformation of more-massive cores to gas giants is reachable before severe depletion of disk gas. This requirement can be satisfied either in extended disks with large scale height via orderly accretion of migrating pebbles or through the mergers of oligarchic protoplanetary embryos, and can account for the correlated occurrence of long-period gas giants and close-in super-Earths.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1962

One-Dimensional Heat Conduction Through the Skin of a Vehicle upon Entering a Planetary Atmosphere at Constant Velocity and Entry Angle

Closed-form solutions of the one-dimensional heat-conduction equations for the flow of heat into a plate with a laminar boundary layer have been obtained for a configuration entering a planetary atmosphere with constant velocity and negative entry angle. The atmospheric density was assumed to obey an exponential law and the temperature was assumed constant initially. The solution is in the form of a Fourier series expansion which, for most practical applications, can be approximated by retaining only one term of the expression. The solution applies to the initial part of the entry before the maximum heating conditions are encountered.

SKIN TEMPERATURE↗