SEARCH · Search NASA

Results for “swelling”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26

All sources NASA NTRS DOE OSTI

NASA NTRS2011

Increased Intracranial Pressure and Visual Impairment Associated with Long-Duration Spaceflight

Although humans have been flying in space since the 1960s, more recent missions have revealed a new suite of physiological adaptations and consequences of space flight. Notably, 60% of long-duration crewmembers (ISS/MIR) and >25% of short-duration (Shuttle) crewmembers have reported subjective degradation in vision (based on debrief comments) (Gibson 2011). Decreased near-visual acuity was demonstrated in 46% of ISS/Mir and 21% of Shuttle crewmembers, resulting in a shift of up to 1-2 diopters in their refractive correction. It is likely that the recently revealed ophthalmic changes have been present since the first days of human space flight, but have been overlooked or attributed to other causations. The reported changes in vision have occurred at various time points throughout missions, with ranging degrees of visual degradation. Although some cases resolved upon return to Earth, several astronauts have not regained preflight visual acuity, indicating that the damage may be permanent. While observing these changes over the years, without other overt symptomology and with the given age range of the flying population, this has largely been attributed to an expected hyperopic shift due to aging. However, the availability of onboard analysis techniques, including visual acuity assessments, retinal imagery, and ultrasounds of the eye and optic nerve tracts, along with more detailed post-flight techniques, has led to the recent recognition of a wider syndrome. Along with vision changes, findings include flattening of the globe, swelling of the optic disc (papilledema), choroidal folds in the retina, swelling of the optic nerve sheath, and visual field defects. It is widely hypothesized that this constellation of findings may be explained by an elevation of intracranial pressure (ICP). Out of the 60% of long-duration astronauts that have reported a subjective degradation in vision, a subset (currently 10 astronauts) have developed this syndrome. The National Aeronautics and Space Administration (NASA) has made it a high priority to understand this syndrome and provide mitigation techniques to protect crewmembers from visual impairment. While there are many possible factors that could contribute to intracranial hypertension associated with spaceflight, the relative contribution of these, as well as the processes by which eye damage occurs as a result of intracranial hypertension, are not fully understood. The observed pathophysiological phenomena are extremely complex and it is likely that multiple factors contribute to their incidence, rather than one simple mechanism. This paper will define and examine the findings in detail, and expound upon the potential contributing factors and their relative contribution to this syndrome.

Marshall-Bowman, Karina↗

NASA NTRSDate not supplied

Preliminary Results From GMAO’s JEDI Based Ocean/Sea-ice Data Assimilation System

Preparations for GMAO’s transition to next generation coupled DA framework includes MOM6 for the ocean and CICE6 for sea ice, alongside assembling the data assimilation systems. The coupled DA system will primarily rely on the Joint Effort for Data Assimilation Integration (JEDI) and involves the use of the Sea-ice Ocean and Coupled Analysis (SOCA) package. The early stages of the work involved developing a coupled, cycling (ocean-only) DA workflow named “Swell”. Some other highlights from this transdisciplinary work: Collaborated with NOAA/EMC to ensure direct comparisons using the same observations and time (July -September 2021) during model development. Conducted in-kind work with the JCSDA to improve various JEDI components. Swell coupled DA framework will be used to assimilate observations from NASA’s PACE and SWOT missions

Dorukhan Ardag↗

DOE OSTI2020

In situ observation of short- and long-timescale material property evolution under extreme conditions

Directly observing the evolution of material performance in-situ under extreme conditions remains a great challenge. Emergent behavior, such as the transition from incubation to steady state void swelling, is often difficult to capture in these conditions. To fill this gap, transient grating spectroscopy (TGS) has been used to collect multi-property information in-situ under high temperature exposure to ion beam irradiation. This all-optical method returns elastic and thermal transport properties with second-scale time resolution. Here, recent work using this methodology to track the evolution of Ni-based solid-solution alloys using the in situ ion irradiation TGS (I3TGS) beamline will be described. Tracking material property evolution during long exposure times (hours) provides a clear indication of when void swelling has occurred. On short timescales (seconds to minutes), observing rapid changes in thermoelastic properties as defect generation is initiated allows a unique window into bulk transient defect populations which are otherwise difficult to observe.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Method for sealing a void in a well using a smart gel sealant

Embodiments of the disclosure include swellable smart gel sealants. In certain embodiments, the smart gel sealants reversibly swell when exposed to a certain trigger, such as temperature or pH. In specific embodiments, the smart gel is disposed within voids in a well and triggered to swell in order to seal the voids. One application of the smart gel sealant is to seal the casing of a well against the leakage of gas, such as CO2.

Goodman, Harvey Edwin↗

DOE OSTI2022

Method for sealing a void in a well using smart gels

Embodiments of the disclosure include swellable smart gel sealants and methods of using smart gel sealants. In certain embodiments, the smart gel sealants reversibly swell when exposed to a certain trigger, such as temperature or pH. In specific embodiments, the smart gel is disposed within voids in a well and triggered to swell in order to seal the voids. One application of the smart gel sealant is to seal the casing of a well against the leakage of gas, such as H2S.

Roback, Robert Clifford↗

DOE OSTI2024

Elongate SiC fuel elements

An elongate fuel element is described that has a silicon carbide cladding enclosing a fuel, such as UO 2 , wherein the fuel is dimensioned relative to the cladding to define gaps at each lateral end of the enclosure sufficiently large such that upon swelling in use, the fuel does not increase the strain on the cladding beyond the limits of the claddings strain tolerance. The lateral gaps at the ends of the fuel allow lateral expansion during swelling that reduces the strain on the cladding.

Long, Yun-Bo↗

DOE OSTI2024

Demonstration and Verification of Thermo-Mechanical Bowing in a Limited Free-Bow SFR Concept Using MOOSE

Core bowing due to thermal gradients and irradiation induced swelling and creep introduces significant reactivity feedback effects in liquid metal-cooled fast spectrum reactors. During startup, normal operations, and transient events, differential thermal and flux gradients cause expansion, creep, and swelling, which results in bowing in preferential directions depending on local material properties and load-pad and restraint-ring design. The bowing phenomenon produces negative reactivity during accident conditions provided the restraint system has been properly designed to optimally guide the deformation outwards in the active core region. Under the Department of Energy Nuclear Energy Advanced Modeling and Simulation program, a Multiphysics Object Oriented Simulation Environment (MOOSE)-based multiphysics approach to model core bowing is being developed. The present work expands on previous modeling of simpler International Atomic Energy Agency (IAEA) verification problems with these tools by modeling IAEA Verification Problem 4, which involves a symmetric sector of a reactor core with ducted assemblies undergoing differential thermal expansion due to thermal gradients bowing outward with duct-to-duct contact. This model is available on the National Reactor Innovation Center Virtual Test Bed repository. This example was verified against benchmark participant results, which includes bowing deformation evaluation and duct-to-duct interactions at load pads with mechanical contact.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2020

Sorption-induced polymer rearrangement: approaches from molecular modeling

With the growing need for chemical separation and chemical storage solutions, polymeric adsorbents have emerged as a promising class of candidate materials because of their potentially tunable sorption properties, membrane structure and relatively cost consciousness. Moreover, the developing field of polymeric membrane materials has shown particular success at integrating both experimental and computational studies. However, these material systems are known to suffer from varying degrees of induced membrane structural rearrangement upon adsorbate uptake, and thus many polymeric membrane performance metrics are often considered to degrade with an increasing number of ‘guest’ species. In this mini–review, we highlight methodology tradeoffs and provide insights into atomistic molecular simulations used to study adsorption with flexible frameworks, which have the potential to predict separation, storage or catalytic capabilities a priori to experimental efforts. Specifically, molecular simulation methods that have been applied to provide predictions of polymeric membrane properties that have included consideration for sorbate–induced polymer chain rearrangement, swelling and/or plasticization are reviewed. Here, the examples and methodologies described provide demonstrations of the applicability of simulations as an approach to understand adsorption–based phenomena at an atomistic/molecular level, and as a tool to carry out screening studies aimed at efficiently providing analysis for a diversity of polymeric adsorbent–adsorbate systems.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Sustainable Use of Chloroprene Rubber Waste as Blend Component with Natural Rubber, Epoxidized Natural Rubber and Styrene Butadiene Rubber

Recycling of rubber waste and finding the effective methods to extend its use are one of major challenges nowadays. The potential approach to reduce rubber waste is to blend it with virgin rubber, perhaps with synergistic advantages. In this study, chloroprene rubber waste (CRw) is used as blend component in binary blends with natural rubber (NR), epoxidized natural rubber with 50 mol% epoxidation level (ENR50), and styrene butadiene rubber (SBR). The effects of blend ratio [95/5, 85/15, 75/25, 65/35 and 50/50 (phr/phr)] on the properties were studied. The results indicate that CRw prolongs scorch and curing times, due to the differences in unsaturation contents and cure incompatibility. The maximum torque (M{sub H}), minimum torque (M{sub L}), and torque difference (M{sub H}–M{sub L}) in all cases increased with CRw content in the blend. Because CRw has a crosslink precursor, crosslink density also increased with CRw content. This is clearly confirmed by the combination of swelling resistance, crosslink density and dynamic mechanical properties observed. SEM micrographs showed mostly rough surface and tearing areas for low CRw contents in the blends. The blends also showed less crack paths with increasing CRw content over 50 phr. Further increase in CRw content obviously enhanced the thermal stability of the blends, with elevated decomposition temperatures in TGA results.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Hopes Beyond PET Recycling: Environmentally Clean and Engineeringly Applicable

Disposal of plastics in the environment has become a core of anxiety in developing countries, while in the developed countries the focus has additionally been placed on design and manufacture of emerging products from plastic wastes—a somewhat vague yet promising horizon. Central to environmental concerns are poly(ethylene terephthalate) (PET) wastes, mainly from post-consumer bottles. Because of a considerable drop in molecular weight in the course of recycling, recycled PETs are not suitable for engineering uses. An efficient yet reasonably green synthesis route is employed here to convert PET wastes into polyurethane, and then carbon nanotubes (CNTs) was added at different levels to obtain nanocomposites with high mechanical properties. The effects of isocyanate (NCO)/hydroxyl (OH) molar ratio and CNTs content on the morphology, physical and mechanical properties were discussed. Chemical/physical crosslink density was calculated from initial slope of stress–strain curves, Mooney–Rivlin plots, strain-hardening modulus, rubbery-plateau storage modulus and swelling data. High tensile strength (300 MPa) and breaking elongation (160%) of polyurethane/CNTs nanocomposites born from PET wastes seemed promising. Microscopic analyses by AFM, SEM, and TEM gave useful information about distribution of CNTs in polyurethane. Lastly, structural changes were correlated to mechanical properties improvement.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Experimental Validation of the Horikx Theory to be Used in the Rubber Devulcanization Analysis

The waste rubber and end-of-life tires management has become a serious environmental problem. It is well known that the best way to carry out the disposal of these wastes is through recycling by devulcanization. Therefore, in the last decades, many methods have been developed to perform this treatment. Nevertheless, the degree and quality of the achieved devulcanization is still difficult to evaluate. The Horikx theory is an approach often used for this purpose. Hence, in this work, the validity of this theory was experimentally checked. The theoretical curve that represents crosslink scission was experimentally built for sulfur-cured natural rubber, sulfur-cured natural rubber reinforced with carbon black, sulfur-cured ethylene propylene diene monomer rubber and peroxide-cured ethylene propylene diene monomer rubber. Several samples with vulcanization (or devulcanization) degree ranging from 0 to 100% were processed, and the corresponding soluble fractions and crosslink densities were measured by the swelling test. The experimental results were in good agreement with the theoretical predictions, independently of the studied material, fact that confirms the validity of the Horikx approach. This finding will contribute to improve the waste rubber devulcanization, and therefore to progress in the environmental protection.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

DOE OSTI2022

Measurement and modeling of methane diffusion in hydrocarbon mixtures

Methane (CH 4 ) dissolution and diffusive mass transfer in liquid hydrocarbon mixtures is of key interest in the context of enhanced oil recovery from tight shales. In this paper, we have studied CH 4 dissolution and diffusion in normal alkane mixtures at a temperature of 50 ⁰C and at pressures of ~8 MPa. For the measurement of CH 4 dissolution/diffusion in bulk liquid hydrocarbon mixtures, we have utilized a high pressure and temperature, constant-volume diffusion (CV-D) setup. Here, we have studied CH 4 diffusion in mixtures with three long-chain normal alkanes: decane (C 10 ), dodecane (C 12 ) and hexadecane (C 16 ). We have measured CH 4 solubility and diffusion in its binary mixtures with each of these three normal alkanes, as well as in ternary and quaternary mixtures. During the experiments, the swelling of the liquid mixture due to CH 4 dissolution was measured in situ via a cathetometer and was subsequently integrated into the data analysis. A key conclusion from this study is that the solubility and transport properties of the multicomponent mixtures can be predicted accurately from binary mixture measurements using an appropriate Equation of State (EOS) and Wilke’s simplification of the classical Maxwell-Stefan (MS) diffusion theory. This observation can facilitate accurate prediction of diffusive mass transfer in more complex liquid hydrocarbon mixtures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Nuclear response of additive manufactured GRCop-84 copper for use in Lower hybrid launchers in a fusion environment

Recent advances in selective laser melting (SLM) 3D printing technology allow additive manufacture of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr 2 Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, in configurations unachievable with conventional machining. Tensile strength and thermal conductivity are compared to other competing high conductivity copper alloys for fusion use. Swelling and conductivity at 100 DPA when exposed to the Hanford Fast Flux Test Facility neutron spectrum is predicted in the 1–2 % and 65-70% IACS range, respectively, by comparison to copper alloys with similar precipitate and grain size. Finally, self-similar ion irradiation of a GRCop-84 target at 430 °C to 20 DPA resulted in no noticeable void formation in FIB cross sections or TEM lamella.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2024

A coarse-grained model of clay colloidal aggregation and consolidation with explicit representation of the electrical double layer

The aggregation of clay minerals in liquid water exemplifies colloidal self-assembly in nature. These negatively charged aluminosilicate platelets interact through multiple mechanisms with different sensitivities to particle shape, surface charge, aqueous chemistry, and interparticle distance and exhibit complex aggregation structures. Experiments have difficulty resolving the associated colloidal assemblages at the scale of individual particles. Conversely, all-atom molecular dynamics (MD) simulations provide detailed insight on clay colloidal interaction mechanisms, but they are limited to systems containing a few particles. We develop a new coarse-grained (CG) model capable of representing assemblages of hundreds of clay particles with accuracy approaching that of MD simulations, at a fraction of the computational cost. Our CG model is parameterized based on MD simulations of a pair of smectite clay particles in liquid water. A distinctive feature of our model is that it explicitly represents the electrical double layer (EDL), i.e., the cloud of charge-compensating cations that surrounds the clay particles. Our model captures the simultaneous importance of long-range colloidal interactions (i.e., interactions consistent with simplified analytical models, already included in extant clay CG models) and short-range interactions such as ion correlation and surface and ion hydration effects. The resulting simulations correctly predict, at low solid-water ratios, the existence of ordered arrangements of parallel particles separated by water films with a thickness up to ~10 nm and, at high solid-water ratios, the coexistence of crystalline and osmotic swelling states, in agreement with experimental observations.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2025

Synthesis of multicomponent oxygen evolution reaction coatings via block copolymer templating with vapor- and solution-phase precursors

Porous mixed transition metal oxide heterostructures are promising electrocatalysts due to their high surface area. However, achieving conformal multicomponent oxide coatings with controlled nanoscale architectures remains challenging. Here, we report a synthesis strategy that integrates solution-based swelling infiltration (SBI) with gas-phase sequential infiltration synthesis (SIS) in a block copolymer template to fabricate porous, high-surface-area, conformal mixed-oxide electrocatalytic coatings. In this approach, a PS75-P4VP25 block copolymer (BCP) film is first infiltrated with transition metal acetylacetonate precursors via SBI, followed by exposure to gas phase precursors of ZnO via SIS process. Thermal annealing of the infiltrated BCP films converts them into all-inorganic Fe–ZnO, Fe–Co–ZnO, and Fe–Ni–ZnO coatings. Electrochemical testing on 70 nm thick conformal coatings demonstrates promising oxygen evolution reaction (OER) activity in alkaline media, with mass-specific current densities up to 1.0 × 10 5 mA/g at an overpotential of 330 mV (vs. RHE) at ultralow loading (~0.005 g/cm 2 ). Among the compositions, Fe–Co–ZnO and amorphous Fe–Ni–ZnO show the best OER performance, delivering current densities of 2.00 and 3.04 mA/cm 2 , respectively, compared to 1.52 mA/cm 2 for Fe–ZnO.. This work establishes SBI–SIS as a versatile route for fabricating nm-thin, high-performance multicomponent oxide heterostructures on cost-efficient supports, enabling efficient catalyst utilization in electrochemical energy conversion application.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Emulation of fast reactor irradiated T91 using dual ion beam irradiation

In this work, dual ion irradiations using 5 MeV defocused Fe 2+ ions and co-injected He 2+ ions were conducted on a ferritic-martensitic steel alloy, T91, in the temperature range of 406 °C–570 °C over a damage range of 14.6–35 dpa followed by characterization of the microstructure using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Dislocation loops were observed to increase in diameter and decrease in density with temperature until only network dislocations were observed at the highest temperatures of 520 °C and 570 °C. Swelling exhibited the expected bell-shaped trend with temperature following the number density of cavities, peaking at 460 °C and with a bimodal size distribution except at 520 °C and 570 °C. Nickel- and silicon-rich clusters formed under dual ion irradiations near the surface at all but the highest temperatures of 520 °C and 570 °C. Very little Cr and Si segregation was observed at lath boundaries while Ni enriched at all temperatures examined. Segregation of Cr and Ni appeared to saturate by 17 dpa, while Si enriched up to 35 dpa. The dislocation and cavity microstructures of dual ion irradiated T91 and T91 irradiated in the BOR-60 fast reactor matched extremely well using a temperature shift of +60–70 °C. However, segregation to grain boundaries and formation of nickel-silicon rich clusters were minimal in the dual ion irradiated T91 and less than that in T91 irradiated in the BOR-60 fast reactor.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Effects of temperature on helium bubble behaviour in Fe–9Cr alloy

In the present study, Fe–9Cr model alloys were irradiated by 275 keV He + ions at 500 to 800 °C to a peak damage level and implanted helium content of 0.5 dpa and 0.75 at% He, respectively. Effects of temperature on He bubble behaviour were studied by transmission electron microscopy (TEM) to reveal the temperature effects. The bubble spatial distribution changes from homogenous at 500 and 600 °C to heterogeneous at 700 and 800 °C, due to preferential bubble precipitation on dislocations and grain boundaries at high temperature. Faceted bubbles with low energy faces along the {001} planes were present at all four temperatures and are attributed to surface energy minimization. Bubble precipitation on the GBs became more pronounced with increasing temperature. Meanwhile, the cavity swelling increased with increasing temperature, from 0.59% at 500 °C to 8.21% at 800 °C with a sharp increase above 700 °C. By analysing the temperature dependence of bubble size and density, a transition temperature between low and high temperature regimes was obtained in terms of different activation energies which are related to different bubble nucleation and formation mechanisms.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Preparation of illite coated geomaterial microfluidic surfaces: Effect of salinity and heat treatment

Unique characteristics of clay (e.g., high surface area, deficiency in positive charges) make any clay abundant shales a good source of adsorbed gas. However, the presence of clay in porous media can also affect shale rock's producibility. The clay-water interaction can cause significant swelling and fines migration in the formation and impair the overall hydrocarbon recovery from shale. Geomaterial micromodels, developed by functionalizing traditional glass or PDMS surfaces with geomaterials (e.g., calcite, Quartz, clay), can represent the physicochemical properties of the natural porous media and have been used during the last few years to understand and evaluate the solid-fluid physicochemical interactions. Here, this study focuses on developing a clay-coated geomaterial surface and investigates the effect of base fluid's salinity on clay adsorption to the glass surface. Glass capillary tubes and straight channel borosilicate glass micromodels are coated with Illite clay to represent the pore-scale clay chemistry of Caney Shale, a Mississippian unconventional play in Southern Oklahoma, USA. 10 wt% of Illite clay slurries made with brines of four different salinities are used to coat the glass-capillary tubes to understand the effect of salinity in clay adsorption on the glass surface and overall coating quality. To achieve a stable coating and evaluate the impact of heat treatment on coating's stability, straight channel glass flow cells coated with Illite clay are heat-treated at low (25 °C) and high temperature (125 °C), and the results are compared with an untreated coated surface. Flooding tests were carried out with brines of different salinities on the coated surface to evaluate the stability of the coating. The experimental results indicated a strong relationship between the brine's salinity and the adsorption of clay particles on the glass surface. An increase in brine concentration resulted in improved adsorption of clay particles on the glass surface. Experiments involving heat treating the glass surface following the coating demonstrated significant improvement in the stability of the coating.

02 PETROLEUM↗