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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 1,747 records · Page 97
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A Mixed Fracture-Matrix Model for Evaluating Well Orientation and Completion Options for the Utah FORGE Site

Orientation and completion for well pairs that have been subjected to multi-zonal stimulation play a critical role in the long-term performance of an Enhanced Geothermal Reservoir. Here we present the development of a methodology to rapidly and efficiently numerically simulate mixed fracture-matrix flow systems for evaluation of well design and completion options. An example evaluation based on a small fracture network representative of FORGE Well 16(A and B)-78(32) follows a discussion of the theory and model validation.

15 GEOTHERMAL ENERGY↗
DOE OSTI2022

DCIF (Directional Cooling-Induced Fracturing) Westerly Granite AE Borehole Damage Effect Test (Task 3-0)

Directional Cooling-Induced Fracturing (DCIF) experiments were conducted on three rectangular Westerly granite blocks (width=depth=4.0", height=2.0") which were preheated to 200, 400, and 600 degree C to induce damage (microcracks) with varying degrees. Liquid nitrogen was poured in a small, 1"-diameter copper cup attached to the top of the sample, and the resulting acoustic emissions (AEs) and temperature changes on the surface of the sample were monitored. The experiments were conducted under one selected biaxial stress (5.8MPa). The obtained AEs were used to determine the microcracking source locations and amplitude, and the associated moment tensors. The onset time of the AEs was correlated with the cooling temperature, which was used to show that the temperature at the onset of microcracking is not affected significantly by the preexisting damage, compared to the impact of the stress in the sample. Included in this submission are the animations of the AE locations and graphics displaying the measured temperature-AE activity changes for samples with different degrees of microcrack damage.

15 GEOTHERMAL ENERGY↗
DOE OSTI2018

The influence of Preslip Sealing on the Permeability Evolution of Fractures and Faults

The evolution of permeability on fractures and faults during the full earthquake cycle is shown to be sensitive to sealing during the repose phase. We explore the combined effect of static loading followed by fracture reactivation on permeability evolution via slide-hold-slide experiments. During the hold periods, permeability exhibits a slow but continuous reduction. The permeability decay is consistent with power law compaction of the aperture coupled with cubic law flow. With increasing hold periods, permeability evolves following reactivation from net reduction to net increase with the magnitude of the permeability change dependent on the hold period. This implies that the tight interlocking of asperities during interseismic repose primes the fault for permeability enhancement following reactivation. The inferred mechanism is via shear dilation with the probable involvement of unclogging. This result identifies that preslip sealing during repose is an essential component in the cyclic permeability evolution throughout the seismic cycle.

58 GEOSCIENCES↗
DOE OSTI2016

Combined Microwave Ablation and Cementoplasty in Patients with Painful Bone Metastases at High Risk of Fracture

PurposeTo retrospectively evaluate the effectiveness of computed tomography-guided percutaneous microwave ablation (MWA) and cementoplasty in patients with painful bone metastases at high risk of fracture.Materials and MethodsThirty-five patients with 37 metastatic bone lesions underwent computed tomography-guided MWA combined with cementoplasty (polymethylmethacrylate injection). Vertebrae, femur, and acetabulum were the intervention sites and the primary end point was pain relief. Pain severity was estimated by visual analog scale (VAS) before treatment; 1 week post-treatment; and 1, 6, and 12 months post-treatment. Functional outcome was assessed by improved patient walking ability. Radiological evaluation was performed at baseline and 3 and 12 months post-procedure.ResultsIn all patients, pain reduction occurred from the first week after treatment. The mean reduction in the VAS score was 84, 90, 90 % at week 1, month 1, and month 6, respectively. Improved walking ability occurred in 100 and 98 % of cases at the 1- and 6-month functional outcome evaluations, respectively. At the 1-year evaluation, 25 patients were alive, and 10 patients (28 %) had died because of widespread disease. The mean reduction in the VAS score and improvement in surviving patients’ walking ability were 90 and 100 %, respectively. No patients showed evidence of local tumor recurrence or progression and pathological fracture in the treated sites.ConclusionOur results suggest that MWA combined with osteoplasty is safe and effective when treating painful bone metastases at high risk of fracture. The number of surviving patients at the 1-year evaluation confirms the need for an effective and long-lasting treatment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Effects of Facet Joint Injection Reducing the Need for Percutaneous Vertebroplasty in Vertebral Compression Fractures

ObjectiveTo evaluate the effects of facet joint injection (FJI) reducing the need for percutaneous vertebroplasty (PVP) in cases of vertebral compression fracture (VCF).Materials and MethodsA total of 169 patients who were referred to the radiology department of our institution for PVP between January 2011 and December 2014 were retrospectively evaluated. The effectiveness of FJI was evaluated by the proportion of patients who cancelled PVP and who experienced reduced pain. In addition, by means of medical chart and MRI review, those clinical factors (age, sex, history of trauma, amount of injected steroids and interval days elapsed between VCF and FJI) and MR image factors (kyphosis angle, height loss, single or multiple level of VCF, burst fracture, central canal compromise, posterior element injury) that were believed to be significant for the effectiveness of FJI were statistically analysed.ResultsIn the 26 patients with FJI prior to PVP, six (23 %) patients cancelled PVP with considerable improvement in reported pain. In the 20 patients with PVP after FJI, improvement in pain after FJI was reported by six patients, resulting in a total of 12 patients (46 %) who experienced reduced pain after FJI. Clinical factors and MR image factors did not show any statistically significant difference between those groups, divided by PVP cancellation and by improvement of pain.ConclusionAfter FJI prior to PVP, about one quarter of patients cancelled PVP due to reduced pain and overall about half of the patients experienced reduced pain.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Multiscale cohesive zone model for propagation of segmented crack fronts in mode I+III fracture

Quasistatic crack propagation in mixed-mode I+III fracture is widely observed to be unstable, the instability being characterized by the segmentation of the parent crack into a periodic array of daughter cracks shaped as flat facets rotated towards the principal stress axis. While there has been recent progress to characterize this instability, no global theory is presently available to describe all aspects of the propagation of the segmented front, including both “local” features like the angle of rotation of the facets and the ratio of their width to their spacing, and “global” ones like the effective energy-release-rate of the segmented crack front and the tendency of the facets to coarsen. This paper embarks on the development of such a theory, based on the assumption that the spacing of the facets is much smaller than their length, and asymptotic matching of outer and inner solutions for the mechanical fields on scales comparable to the facet length and spacing, respectively. Here, the inner problem is shown to reduce to a 2D linear elastic fracture mechanics problem in the plane perpendicular to the crack propagation axis. The solution of this problem is used to develop an effective cohesive zone description of the crack front on a scale much larger than the facet spacing. Such a description leads to a system of 1D integral equations for the outer mechanical fields on the cohesive zone, which may be solved numerically. Numerical examples are given that notably illustrate the prediction of the effective energy-release-rate of the segmented crack front in terms of the various geometrical parameters; this energy-release-rate is predicted to be smaller for a segmented front than for the parent planar front, with the conclusion that segmentation acts as a toughening mechanism. Implications upon the phenomenon of facet coarsening are also briefly discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Evolution of damage and failure in an additively manufactured 316L SS structure: experimental reinvestigation of the third Sandia fracture challenge

The third Sandia Fracture Challenge (SFC3) was a benchmark problem for comparing experimental and simulated ductile deformation and failure in an additively manufactured (AM) 316L stainless steel structure. One surprising observation from the SFC3 was the Challenge-geometry specimens had low variability in global load versus displacement behavior, attributed to the large stress-concentrating geometric features dominating the global behavior, rather than the AM voids that tend to significantly influence geometries with uniform cross-sections. This current study reinvestigates the damage and failure evolution of the Challenge-geometry specimens, utilizing interrupted tensile testing with micro-computed tomography (micro-CT) scans to monitor AM void and crack growth from a virgin state through complete failure. This study did not find a correlation between global load versus displacement behavior and AM void attributes, such as void volume, location, quantity, and relative size, which incidentally corroborates the observation from the SFC3. However, this study does show that the voids affect the local behavior of damage and failure. Surface defects (i.e. large voids located on the surface, far exceeding the nominal surface roughness) that were near the primary stress concentration affected the location of crack initiation in some cases, but they did not noticeably affect the global response. The fracture surfaces were a combination of classic ductile dimples and crack deviation from a more direct path favoring intersection with AM voids. Even though the AM voids promoted crack deviation, pre-test micro-CT scan statistics of the voids did not allow for conclusive predictions of preferred crack paths. This study is a first step towards investigating the importance of voids on the ductile failure of AM structures with stress concentrations.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Coupled THM Modeling of Hydroshearing Stimulation in Tight Fractured Volcanic Rock

Here, we use the TOUGH-FLAC simulator for coupled thermo–hydro-mechanical modeling of well stimulation for an Enhanced Geothermal System (EGS) project. We also analyze the potential for injection-induced fracturing and reactivation of natural fractures in a porous medium with associated permeability enhancement. Our analysis aims to understand how far the EGS reservoir may grow and how the hydroshearing process relates to system conditions. We analyze the enhanced reservoir, or hydrosheared zone, by studying the extent of the failure zone using an elasto-plastic model, and accounting for permeability changes as a function of the induced stresses. For both fully saturated and unsaturated medium cases, the results demonstrate how EGS reservoir growth depends on the initial fluid phase, and how the reservoir extent changes as a function of two critical parameters: (1) the coefficient of friction, and (2) the permeability-enhancement factor. Furthermore, while well stimulation is driven by pressure exceeding the hydroshearing threshold, the modeling also demonstrates how injection-induced cooling further extends the effects of stimulation.

15 GEOTHERMAL ENERGY↗
DOE OSTI2012

A High Vacuum Fracture Facility for Molecular Interactions

The objective of this program was to examine, via experiment and atomistic and continuum analysis, coordinated noncovalent bonding over a range of length scales with a view to obtaining modulated, patterned and reversible bonding at the molecular level. The first step in this project was to develop processes for depositing self-assembled monolayers (SAMs) bearing carboxylic acid and amine moieties on Si (111) surfaces and probe tips of an interfacial force microscope (IFM). This allowed the adhesive portion of the interactions between functionalized surfaces to be fully captured in the force-displacement response (force profiles) that are measured by the IFM. The interactionswere extracted in the form of traction-separation laws using combined molecular and continuum stress analyses. In this approach, the results of molecular dynamics analyses of SAMs subjected to simple stress states are used to inform continuum models of their stress-strain behavior. Continuum analyses of the IFM experiment were then conducted, which incorporate the stress-strain behavior of the SAMs and traction-separation relations that represent the interactions between the tip and functionalized Si surface. Agreement between predicted and measured force profiles was taken to imply that the traction-separation relations have been properly extracted. Scale up to larger contact areas was considered by forming Si/SAM/Si sandwiches and then separating them via fracture experiments. The mode 1 traction-separation relations have been extracted using fracture mechanics concepts under mode 1 and mixed-mode conditions. Interesting differences were noted between the three sets of traction-separation relations.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Near-Surface Layer Perforations as Precursors to Fracture in Accumulative Roll Bonding of a Multilayered Metal Composite

We use micro-computed tomography (µ-CT) to characterize the sizes, shapes, and locations of layer perforation (LP) defects in laminates of copper (Cu) and tantalum (Ta) processed by accumulative roll bonding (ARB). One—termed Cu/Ta—was processed from an initial stacking of seven alternating Cu and Ta sheets, with the exterior sheets being Cu. In the other—termed Ta/Cu—the exterior sheets are Ta. Cu/Ta remained intact during processing and exhibits an approximately uniform spatial distribution of LPs. By contrast, Ta/Cu fractured by longitudinal splitting. LPs in this latter sample are concentrated near the sample surfaces. Moreover, their density increases with decreasing distance to the fracture surface. Furthermore, these findings show that materials undergoing ARB may remain intact, despite profuse formation of LPs, provided that the LPs are uniformly distributed. However, a non-uniform distribution of LPs is correlated with longitudinal splitting.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Image-Based Fracture Surface Defect Characterization Methods for Additively Manufactured Ti-6Al-4V Tested in Fatigue

Abstract Fatigue initiation in additively manufactured samples/parts often occurs at processed-induced defects such as lack-of-fusion (LoF), keyhole, or other morphological/microstructural defects that have unique characteristics and measurable qualities. Attempts at identifying and minimizing such defects have utilized optimized processing conditions along with in situ and ex situ characterization that includes metallography and/or X-ray computed tomography (XCT). This paper highlights the benefits of using fracture surface analyses to detect and quantify defects that may not be detected by metallography/XCT due to sectioning and resolution limits. In addition to using manual quantification of fatigue initiating LoF and keyhole defects on fracture surfaces, image-based machine learning using convolutional neural networks such as U-Net were also used to automate the process. Statistical analyses were used to identify the extreme cases of defects that initiated and accelerated fatigue and to model the distribution of defect size and shape characteristics to distinguish the type of defect. Initial results show agreement between trained machine learning models and ground truth data in defect segmentation, and the distributions of defect characteristics are distinguishable to particular process-induced defect types.

Materials Science↗
DOE OSTI2023

Long-term CRISPR locus dynamics and stable host-virus co-existence in subsurface fractured shales

Viruses are the most ubiquitous biological entities on Earth. Even so, elucidating the impact of viruses on microbial communities and associated ecosystem processes often requires identification of unambiguous host-virus linkages-an undeniable challenge in many ecosystems. Subsurface fractured shales present a unique opportunity to first make these strong linkages via spacers in CRISPR-Cas arrays and subsequently reveal complex long-term host-virus dynamics. Here, we sampled two replicated sets of fractured shale wells for nearly 800 days, resulting in 78 metagenomes from temporal sampling of six wells in the Denver-Julesburg Basin (Colorado, USA). At the community level, there was strong evidence for CRISPR-Cas defense systems being used through time and likely in response to viral interactions. Within our host genomes, represented by 202 unique MAGs, we also saw that CRISPR-Cas systems were widely encoded. Together, spacers from host CRISPR loci facilitated 2,110 CRISPR-based viral linkages across 90 host MAGs spanning 25 phyla. We observed less redundancy in host-viral linkages and fewer spacers associated with hosts from the older, more established wells, possibly reflecting enrichment of more beneficial spacers through time. Leveraging temporal patterns of host-virus linkages across differing well ages, we report how host-virus co-existence dynamics develop and converge through time, possibly reflecting selection for viruses that can evade host CRISPR-Cas systems. Together, our findings shed light on the complexities of host-virus interactions as well as long-term dynamics of CRISPR-Cas defense among diverse microbial populations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Evaluation of a cation-exchanging tracer to interrogate fracture surface area in enhanced geothermal systems

Column transport experiments were conducted at 225 °C and 300 °C using a crushed amphibolite schist from Fenton Hill, NM to evaluate lithium ion as a cation-exchanging tracer to interrogate fracture surface area in enhanced geothermal systems. Lithium exchange proceeded to equilibrium rapidly, and Li + selectivity doubled from 225 °C to 300 °C, with the selectivity at both temperatures being much greater than at room temperature. Also, cation exchange was deduced to be occurring primarily in a thin “rim zone” (<0.05 mm) on the rock surfaces. These results are all encouraging for using lithium ion to interrogate fracture surface area in enhanced geothermal systems.

15 GEOTHERMAL ENERGY↗
DOE OSTI2018

Avoiding Fracture in a Conversion Battery Material through Reaction with Larger Ions

Conversion and alloying electrode materials offer high specific capacity for emerging sodium- and potassium-ion batteries, but the larger volume changes compared to reaction with lithium are thought to limit cyclability. The reaction mechanisms of many materials with Na + and K + are unknown, however, and this knowledge is key for engineering mechanically resilient materials. Here, in situ transmission electron microscopy is used to uncover the nanoscale transformations during the reaction of FeS 2 electrode materials with Li + , Na + , and K + . Surprisingly, despite larger volume changes during the conversion reaction with Na + and K + , the FeS 2 crystals only fracture during lithiation. Modeling of reaction-induced deformation shows that the shape of the two-phase reaction front influences stress evolution, and unique behavior during lithiation causes stress concentrations and fracture. The larger volume changes in Na- and K-ion battery materials may therefore be managed through understanding and control of reaction mechanisms, ultimately leading to better alkali-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Deformation and Fracture Behaviors of Cylindrical Battery Shell During Thermal Runaway

Thermal runaway is one of the catastrophic failure modes of lithium-ion cells. During thermal runaway in cylindrical cells, sidewall shell rupture has been identified as a contributing factor for thermal runaway propagation in battery packs. Herein, the deformation and fracture behaviors of the battery shell during thermal runaway are investigated based on in-situ and ex-situ characterization as well as physics-based modeling. The deformation and fracture modes of the battery shell with/without Carbon Fiber Reinforced Polymer (CFRP) sleeves are identified. In the simulation, the strain introduced by thermal expansion of the system is considered, as well as the thermal and strain rate effects on the plastic stage. The final cell shell modeling is validated by cell thermal runaway tests. Results reveal the quantitative relation between shell deformation behaviors and the pressure and temperature distribution. Both the experiment and model demonstrate the effectiveness of adding a tight-fitting CFRP sleeve around the cell in limiting the side-wall rupture of the shell. The use of CFRP tubes introduces a novel phenomenon in the context of uneven temperature distribution. Results shed light on the mechanistic analysis of a cell side-wall rupture during thermal runaway and provide essential guidance for the next-generation safe battery design.

battery casing↗
DOE OSTI2022

Continuous electrocoagulation-membrane distillation unit for treating hydraulic fracturing produced water

Hydraulic fracturing oil and gas produced water is frequently highly impaired. While it is often deep well injected, there is great interest in treating this water for beneficial uses. Given the complexity of these produced waters, multiple unit operations are necessary. Electrocoagulation has been considered as a promising pretreatment technology. Here electrocoagulation is considered as a pretreatment prior to membrane distillation. The focus of this work is on understanding the electrocoagulation process in order to design an integrated unit operation. Electrocoagulation is used to remove organic compounds that will foul the membrane leading to membrane failure during membrane distillation. Using aluminum or iron electrodes, half-cell reactions in the electrocoagulation cell and electrode potentials have been calculated. Electrocoagulation was conducted using a continuous electrocoagulation reactor with actual produced water using aluminum, iron or mixed aluminum and iron electrodes. Here, the results obtained here indicate that electrocoagulation can obtain good removal efficiency of total organic carbon (TOC) by using different reaction conditions. Removal of organic compounds is essential to minimize fouling during membrane distillation. Further the performance of the electrocoagulation process depends strongly on the quality of the feed water. Insoluble species were more effectively coagulated than dissolved organic species. Continuous electrocoagulation shows great potential as a scalable unit operation for pretreating hydraulic fracturing produced water.

42 ENGINEERING↗
DOE OSTI2016

Tensile deformation and fracture properties of a 14YWT nanostructured ferritic alloy

Here, a new larger heat of a 14YWT nanostructured ferritic alloy (NFA), FCRD NFA-1, was synthesized by ball milling FeO and argon atomized Fe-14Cr-3W-0.4Ti-0.2Y (wt%) powders, followed by hot extrusion, annealing and cross rolling to produce an ≈10 mm-thick plate. NFA-1 contains a bimodal size distribution of pancake-shaped, mostly very fine scale, grains. The as-processed plate also contains a large population of microcracks running parallel to its broad surfaces. The small grains and large concentration of Y–Ti–O nano-oxides (NOs) result in high strength up to 800 °C. The uniform and total elongations range from ≈1–8%, and ≈10–24%, respectively. The strength decreases more rapidly above ≈400 °C and deformation transitions to largely viscoplastic creep by ≈600 °C. While the local fracture mechanism is generally ductile-dimple microvoid nucleation, growth and coalescence, perhaps the most notable feature of tensile deformation behavior of NFA-1 is the occurrence of periodic delamination, manifested as fissures on the fracture surfaces.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Towards real-time forecasting of natural gas production by harnessing graph theory for stochastic discrete fracture networks

In this work, we compare hydrocarbon production curves obtained from a graph-based reduced-order model with the high-fidelity Discrete Fracture Network (DFN) predictions for a fracture network created using data from a real shale site. We observe that the bounds for the high fidelity DFN model lie within the bounds for the reduced order model, implying that the reduced-order model provides a conservative estimate. Moreover, we found that except for first-passage times and late arriving mass, the production curves from the reduced-order model predict transport accurately. However, it is to be noted that the results are inspite of trading a three-dimensional geometry for a reduced system in the form of a graph, one that is 500–1000 times faster in terms of computational efficiency (for this particular application). In addition, we also compare the production curves for large drawdown and small drawdown using our graph approach. The reduced-order model is successful in showing that the long term productivity is higher in case of small drawdown although the initial productivity is higher for large drawdown. Thus, this reduced-order model offers great potential in uncertainty quantification for production, as well as in providing operators with information to make real-time decisions for optimal production.

03 NATURAL GAS↗