Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “REFRACTORY”

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.

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

At least 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Transcatheter Arterial Embolization With Spherical Embolic Agent for Pulmonary Metastases From Renal Cell Carcinoma

Purpose: This retrospective study aimed to evaluate the safety and local efficacy of transcatheter arterial embolization (TAE) with superabsorbent polymer microspheres (SAP-MS) in patients with pulmonary metastases from renal cell carcinoma (RCC). Methods: Sixteen patients with unresectable pulmonary metastases from RCC refractory to standard therapy were enrolled to undergo TAE with the purpose of mass reduction and/or palliation. The prepared SAP-MS swell to approximately two times larger than their dry-state size (100-150 {mu}m [n = 14], 50-100 {mu}m [n = 2]). Forty-nine pulmonary nodules (lung n = 22, mediastinal lymph node n = 17, and hilar lymph node n = 10) were selected as target lesions for evaluation. Local tumor response was evaluated 3 months after TAE according to Response Evaluation Criteria in Solid Tumors (RECIST; version 1.1). The relationship between tumor enhancement ratio by CT during selective angiography and local tumor response was evaluated. Results: The number of TAE sessions per patient ranged from 1 to 5 (median 2.9). Embolized arteries at initial TAE were bronchial arteries in 14 patients (87.5 %) and nonbronchial systemic arteries in 11 patients (68.8 %). Nodule-based evaluation showed that 5 (10.2 %) nodules had complete response, 17 (34.7 %) had partial response, 15 (30.6 %) had stable disease, and 12 (24.5 %) had progressive disease. The response rate was significantly greater in 22 lesions that had a high tumor enhancement ratio than in 27 lesions that had a slight or moderate ratio (90.9 vs. 7.4 %, p = 0.01). Severe TAE-related adverse events did not occur. Conclusion: TAE with SAP-MS might be a well-tolerated and locally efficacious palliative option for patients with pulmonary metastases from RCC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Microwave Ablation (MWA) for the Treatment of a Solitary, Chemorefractory Testicular Cancer Liver Metastasis

We present a case of a patient with stage IIIC metastatic seminoma with a persistent chemorefractory liver lesion. The patient was deemed a poor surgical candidate due to the tumor’s aggressive biology with numerous other liver lesions treated with chemotherapy and a relatively high probability for additional recurrences. Further chemotherapy with curative intent was not a feasible option due to the fact that the patient had already received second-line high-dose chemotherapy and four cycles of third-line treatment complicated by renal failure, refractory thrombocytopenia, and debilitating neuropathy. After initial failure of laser, microwave ablation of the chemorefractory liver metastasis resulted in prolonged local tumor control and rendered the patient disease-free for more than 35 months, allowing him to regain an improved quality of life.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

23 Lung Metastases Treated by Radiofrequency Ablation Over 10 Years in a Single Patient: Successful Oncological Outcome of a Metastatic Cancer Without Altered Respiratory Function

An 82-year-old man, who was diagnosed in 2002 with an oncocytic (Hürthle cell) thyroid carcinoma, was initially treated by local surgery and was refractory to radioiodine treatment. The patient had successive secondary recurrences from 2006 onwards. Metastases were suspected due to an elevation of thyroglobulin in serum. Hypermetabolic nodules were targeted using FDG PET as well as CT-guided radiofrequency ablations. Thyroglobulin levels decreased following each procedure. 10 years later, tolerance and efficacy are excellent; 23 lung metastases have been treated during 11 sessions without current relapse. Respiratory function and quality of life are not altered. This report illustrates how radiofrequency ablation can be efficiently integrated into the long-term management of poorly aggressive oligometastatic cancer, in combination with other local and/or systemic therapies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Recurrence of Lower Urinary Tract Symptoms Following Prostate Artery Embolization for Benign Hyperplasia: Single Center Experience Comparing Two Techniques

PurposeTo compare recurrence of lower urinary tract symptoms (LUTS) recurrence at 12 months following original prostate artery embolization (oPAE) or “proximal embolization first, then embolize distal” (PErFecTED) PAE for benign prostatic hyperplasia (BPH).Materials and Methods105 consecutive patients older than 45 years, with prostate size greater than 30 cm{sup 3}, International Prostate Symptom Score (IPSS) ≥ 8, quality of life (QoL) index ≥ 3, and refractory status or intolerance of medical management were prospectively enrolled between June 2008 and August 2013. The study was IRB-approved, and all patients provided informed consent. Patients underwent oPAE or PErFecTED PAE and were followed for at least 12 months. Technical success was defined as bilateral embolization and clinical success (non-recurrence) was defined as removal of the Foley catheter in patients with urinary retention, IPSS < 8 and QoL index < 3 at 12 months of follow-up. Nonparametric statistics were used to compare the study groups due to the size of the study population and distributions of clinical data.Results97 patients had 12-month data and were categorized as oPAE without recurrence (n = 46), oPAE with recurrence (n = 13), PErFecTED without recurrence (n = 36), or PErFecTED with recurrence (n = 2). Recurrence was significantly more common in oPAE patients (χ{sup 2}, p = 0.026). Unilateral embolization was significantly associated with recurrence among patients who underwent oPAE (χ{sup 2}, p = 0.032).ConclusionsBoth oPAE and PErFecTED PAE are safe and effective methods for treatment of LUTS, but PErFecTED PAE is associated with a significantly lower rate of symptom recurrence.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Clinical Outcomes of Transcatheter Arterial Embolisation for Chronic Knee Pain: Mild-to-Moderate Versus Severe Knee Osteoarthritis

Purpose: This retrospective study was conducted to compare the clinical outcomes of transcatheter arterial embolisation for chronic knee pain in patients with mild-to-moderate versus severe knee osteoarthritis. Materials and Methods: This study included patients (n = 41) who were refractory to conservative treatments and who underwent transcatheter arterial embolisation using imipenem/cilastatin sodium between June 2017 and July 2018. A total of 71 knees, including 30 bilateral cases, were treated and categorised into two groups according to the Kellgren–Lawrence grade: mild-to-moderate osteoarthritis (n = 59, Kellgren–Lawrence grade 1–3) and severe osteoarthritis (n = 12, Kellgren–Lawrence grade 4). The clinical outcomes were measured by the visual analogue scale score. Results: There were no significant differences in age, body mass index or baseline visual analogue scale scores between the two groups. The mean visual analogue scale scores in the mild-to-moderate osteoarthritis group were significantly decreased at 1 day, 1 week, 1 month, 3 months, and 6-months (5.5 at baseline vs. 3.2, 3.1, 2.9, 2.2, and 1.9, after treatment; all P = .00). These improvements were maintained at a mean of 10 ± 3 months (range 6–19 months) post-treatment. The visual analogue scale scores were significantly decreased in the severe osteoarthritis group for 1 month post-treatment (6.3 at baseline vs. 4.1, 4.1, and 4.4 at 1 day, 1 week, and 1 month; all P < .01). However, a decrease in pain was not statistically significant from 3 to 6 months (5.4 and 5.9 at 3 months and 6 months, respectively). Conclusion: Transcatheter arterial embolisation effectively relieved pain in patients with mild-to-moderate osteoarthritis. In patients with severe osteoarthritis, pain severity decreased for 1 month but gradually increased to the initial severity score within 3 months. Level of Evidence: 4, Case series.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

58 GEOSCIENCES↗
DOE OSTI2022

Boundary characterization using 3D mapping of geometrically necessary dislocations in AM Ta microstructure

Additive manufacturing (AM) of high strength metallic materials produces microstructures and defects that deviate substantially from those created through conventional manufacturing methods. It has recently been demonstrated that with application of extreme energy densities, a high-temperature refractory metal, tantalum (Ta), can be printed to a fully dense state with exceptionally low porosity. Here we employ a combination of three-dimensional electron backscattered diffraction (EBSD) TriBeam technology and crystallographic geometrically necessary dislocation (GND) theory to characterize the microstructure and defect boundaries of this unusual AM product. Two-dimensional (2D) EBSD and these three-dimensional (3D) measurements indicate that the microstructure of AM Ta is highly oriented <111> along the build direction, yet at the same time contains large crystallographic orientation gradients that span mm’s across the build. Crystallographic GND density analysis of the 3D microstructure reveals that highly misoriented subboundaries exist within this strongly textured microstructure that have large dislocation densities of 1×10 16 m –2 , just as large as those comprising the high-angle grain boundaries (HAGBs) in the same material. The 3D crystallographic GND density mapping reveals these subboundaries are part of a complex, finely spaced network that extends throughout the entire microstructure. Here, the orientation of these boundaries can be related to the scan strategy used during printing. TEM measurements corroborate an extremely high dislocation density at the microscale and indicate a cell-like dislocation network structure existing in the AM Ta at the sub-μm scale.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Rapid fusion method for determination of plutonium isotopes in large rice samples

A new rapid fusion method for the determination of plutonium in large rice samples has been developed at the Savannah River National Laboratory (Aiken, SC, USA) that can be used to determine very low levels of plutonium isotopes in rice. The recent accident at Fukushima Nuclear Power Plant in March, 2011 reinforces the need to have rapid, reliable radiochemical analyses for radionuclides in environmental and food samples. Public concern regarding foods, particularly foods such as rice in Japan, highlights the need for analytical techniques that will allow very large sample aliquots of rice to be used for analysis so that very low levels of plutonium isotopes may be detected. The new method to determine plutonium isotopes in large rice samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with TEVA Resin cartridges. The method can be applied to rice sample aliquots as large as 5 kg. Plutonium isotopes can be determined using alpha spectrometry or inductively-coupled plasma mass spectrometry (ICP-MS). The method showed high chemical recoveries and effective removal of interferences. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory plutonium particles are effectively digested. The MDA for a 5 kg rice sample using alpha spectrometry is 7E-5 mBq g{sup -1}. The method can easily be adapted for use by ICP-MS to allow detection of plutonium isotopic ratios.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2015

Rapid fusion method for the determination of Pu, Np, and Am in large soil samples

A new rapid sodium hydroxide fusion method for the preparation of 10-20 g soil samples has been developed by the Savannah River National Laboratory (SRNL). The method enables lower detection limits for plutonium, neptunium, and americium in environmental soil samples. The method also significantly reduces sample processing time and acid fume generation compared to traditional soil digestion techniques using hydrofluoric acid. Ten gram soil aliquots can be ashed and fused using the new method in 1-2 hours, completely dissolving samples, including refractory particles. Pu, Np and Am are separated using stacked 2mL cartridges of TEVA and DGA Resin and measured using alpha spectrometry. The method can be adapted for measurement by inductively-coupled plasma mass spectrometry (ICP-MS). Two 10 g soil aliquots of fused soil may be combined prior to chromatographic separations to further improve detection limits. Total sample preparation time, including chromatographic separations and alpha spectrometry source preparation, is less than 8 hours.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Rapid method to determine 89 Sr/ 90 Sr in large concrete samples

Here, a new rapid method has been developed that provides high quality low-level measurements of 89,90 Sr in concrete samples with an MDA (Minimum Detectable Activity) of <1 mBq g -1 . The new method is fast, meets new decommissioning regulatory limits and is robust even if refractory particles are present. The method utilizes a rapid fusion to ensure total dissolution of samples and rapid preconcentration and separation of 89,90 Sr from 5-10 g concrete samples. When, the 89 Sr/ 90 Sr ratio is high, Sr can be isolated from up to 5g concrete samples, total 89/90 Sr measured, and then 90Sr determined via 90 Y separated after a period of ingrowth. Another approach allows the immediate determination of 90 Sr in 10 g concrete aliquots without waiting for 90 Y ingrowth, in instances where the shorter lived 89 Sr is unlikely to be encountered.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2022

Gamma-ray spectrometry analysis methods for radioisotope dissolution and mixing for nuclear forensics applications

We report the production of surrogate nuclear explosive debris involves the dissolution of irradiated fissile material, elemental isolation, and recombination based on required fission product ratios. Gamma-ray spectrometry is used following each step to assess the radioactive fission product inventory. A high-purity germanium detector is used to measure each sample, and the detector efficiencies are determined prior to sample measurements. Through radiochemical techniques, elements are isolated and recombined into samples with specific fission product ratios. As a result, a matrix-based approach can account for imperfect chemical separations to calculate the proper mixture volumes to obtain intended volatile-to-refractory fission product ratios, or R-values.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2026

Ra-226 extraction and purification from simulated uranium tailings

Growing demand for Ac-225 has outstripped current production, increasing interest in alternative production routes. Furthermore, these often rely on irradiations of Ra-226, yet Ra-226 supplies are also limited. Uranium tailings provide an abundant source of Ra-226, though separation from these complex matrices remains challenging. A laboratory-scale process was developed to recover Ra-226 from simulated U-tailings. After acid leaching, Ra remained adsorbed on refractory oxides and silicates. An additional CaCl₂ leach of the residue raised recovery to ~ 64%. Subsequent purifications, including precipitation, ion-exchange, and extraction chromatography (TK101), achieved chemical yields up to 73 ± 7%, producing 7.68 ± 0.1 µCi of high-purity Ra-226.

and nuclear chemistry↗
DOE OSTI2025

Metasomatic Alteration of Type 3 Ordinary and Carbonaceous Chondrites

Metasomatism refers to the process during which a pre-existing rock undergoes compositional and mineralogical transformations associated with chemical reactions triggered by the reaction of fluids which invade the protolith. It changes chemical compositions of minerals, promotes their dissolution and precipitation of new minerals. In this paper, we review metasomatic alteration of type 3 ordinary (H, L, LL) and carbonaceous (CV, CO, CK) chondrites, including (i) secondary mineralization, (ii) physicochemical conditions, (iii) chronology ( 53 Mn- 53 Cr, 26 Al- 26 Mg, 129 I- 129 Xe) of metasomatic alteration, (iv) records of metasomatic alteration in H, O, N, C, S, and Cl isotopic systematics, (v) effects of metasomatic alteration on O- and Al-Mg-isotope systematics of primary minerals in chondrules and refractory inclusions, and (vi) sources of water ices in metasomatically altered CV, CO, and ordinary chondrites, and outline future studies.

129I-129Xe chronology↗
DOE OSTI2019

Fabrication, Analysis of Microstructure and Oxidation Resistance of Cemented C/C Composites by Laser

Cylindrical carbon–carbon composites have been cemented using a CO{sub 2} laser actuated by a raster scanning mirror system in a four-step sequence. Complete and homogenous surface cementation as well as thermal stability of the composites was sought after and achieved. The line of heat created from the laser beam impinged parallel to the axis of the pre-coated cylinder, while suspended from one end and slowly rotated. Four slurry compositions, all containing chloride salts from refractory elements, some combined with silicon, were pre-deposited by air spraying it over each specimen and then laser treated sequentially. Confined heat sublimed the chlorine ions resulting in silicide compounds that reacted with the carbon substrate to form a bonding layer. Microstructure characterization was performed using scanning electron microscopy, energy-dispersive spectroscopy and x-ray diffraction, immediately after the cementation was consolidated and after heat treated under argon. Preliminary oxidation weight loss tests were performed up to 1423 K under argon and air, revealing a 9.8 and 30.6% weight reduction, respectively, after 9 h of exposure. Cemented specimens were then coated with a glass overcoat layer that allowed them to perform moderately better against oxidation achieving up to a 28% weight loss after 20 h at 1273 K in air.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Interdiffusion between Zr Diffusion Barrier and U-Mo Alloy

U-Mo alloys are being developed as low enrichment uranium fuels under the Reduced Enrichment for Research and Test Reactor (RERTR) program. Significant reactions have been observed between U-Mo fuels and Al or Al alloy matrix. Refractory metal Zr has been proposed as barrier material to reduce the interactions. In order to investigate the compatibility and barrier effects between U-Mo alloy and Zr, solid-to-solid U-10wt.%Mo vs. Zr diffusion couples were assembled and annealed at 600, 700, 800, 900 and 1000 °C for various times. The microstructures and concentration profiles due to interdiffusion and reactions were examined via scanning electron microscopy and electron probe microanalysis, respectively. Intermetallic phase Mo2Zr was found at the interface and its population increased when annealing temperature decreased. Diffusion paths were also plotted on the U-Mo-Zr ternary phase diagrams with good consistency. The growth rate of interdiffusion zone between U-10wt.%Mo and Zr was also calculated under the assumption of parabolic diffusion, and was determined to be about 103 times lower than the growth rate of diffusional interaction layer found in diffusion couples U-10wt.%Mo vs. Al or Al-Si alloy. Other desirable physical properties of Zr as barrier material, such as neutron adsorption rate, melting point and thermal conductivity are presented as supplementary information to demonstrate the great potential of Zr as the diffusion barrier for U-Mo fuel systems in RERTR.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Constitutive Model for the Time-Dependent Mechanical Behavior of 430 Stainless Steel and FeCrAlY Foams in Sulfur-Bearing Environments

The mechanical behavior of 430 stainless steel and pre-oxidized FeCrAlY open-cell foam materials of various densities was evaluated in compression at temperatures between 450 C and 600 C in an environment containing hydrogen sulfide and water vapor. Both materials showed negligible corrosion due to the gaseous atmosphere for up to 168 hours. The monotonic stress-strain response of these materials was found to be dependent on both the strain rate and their density, and the 430 stainless steel foam materials exhibited less stress relaxation than FeCrAlY for similar experimental conditions. Using the results from multiple hardening-relaxation and monotonic tests, an empirical constitutive equation was derived to predict the stress-strain behavior of FeCrAlY foams as a function of temperature and strain rate. These results are discussed in the context of using these materials in a black liquor gasifier to accommodate the chemical expansion of the refractory liner resulting from its reaction with the soda in the black liquor.

Constitutive Model↗
DOE OSTI2018

Advanced Real-Time Optical Imaging: Part I

Materials research is significantly assisted by information gathered from imaging. Images may be macroscopic or microscopic; different imaging techniques ranging from conventional microscopes to synchrotron tomography are selected for various research purposes and goals. While most materials imaging is performed in static environments at room temperature because of its appropriateness (or due to device limitations), simple optical imaging may transform into a powerful tool if it is dynamically captured during materials treatments, processing, or physical/chemical exposures. Real-time observations this way provide researchers with vital information on materials behaviors under controlled but various conditions. In the field of energy materials, it is not uncommon to require materials studies under high-temperature, high-pressure, and/or corrosive conditions. In gasifiers, for example, investigations of sensor alloy degradation, slag-refractory reactions, and coal agglomeration require samples to undergo severe environments where direct imaging would be difficult using conventional experimental methods. Finally, while post mortem analysis often provides critical information, interpretation may sometimes be complicated without confirming such occurrences under those conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Photo-controlled release of paclitaxel and model drugs from RNA pyramids

Stimuli-responsive release of drugs from a nanocarrier in spatial-, temporal-, and dosage-controlled fashions is of great interest in the pharmaceutical industry. Paclitaxel is one of the most effective and popular chemotherapeutic drugs against a number of cancers such as metastatic or nonmetastatic breast cancer, non–small cell lung cancer, refractory ovarian cancer, AIDS-related Kaposi’s sarcoma, and head and neck cancers. Here, by taking the advantage of RNA nanotechnology in biomedical and material science, we developed a three-dimensional pyramid-shaped RNA nanocage for a photocontrolled release of cargo, using paclitaxel as a model drug. The light-triggered release of paclitaxel or fluorophore Cy5 was achieved by incorporation of photocleavable spacers into the RNA nanoparticles. Upon irradiation with ultraviolet light, cargos were rapidly released (within 5 min). In vitro treatment of breast cancer cells with the RNA nanoparticles harboring photocleavable paclitaxel showed higher cytotoxicity as compared to RNA nanoparticles without the photocleavable spacer. The methodology provides proof of concept for the application of the light-triggered controlled release of drugs from RNA nanocages.

59 BASIC BIOLOGICAL SCIENCES↗