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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

A space radiation shielding model of the Martian radiation environment experiment (MARIE)

The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. Onboard the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20-500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

NASA Center JSC↗
DOE OSTI2015

Experimental and theoretical study of organometallic radiation-protective materials adapted to radiation sources with a complex isotopic composition

The significance of optimizing the content of components of a radiation-protective material, which is determined by the isotopic composition of radioactive contamination, depending on the reactor type, operating time, and other factors is demonstrated. The results of computational and experimental investigation of the gamma-radiation attenuation capacity of homogenous radiation-protective materials with different fillers are reported.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2014

Black Carbon Radiative Forcing over the Tibetan Plateau

We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. Our best estimate of the annual BC snow albedo forcing in the Plateau is 2.9 W m-2 (uncertainty: 1.5–5.0 W m-226 ). We find that BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing and coated BC increases the forcing by 30-50% compared with uncoated BC, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. Our best estimate of the annual BC DRF at the top of the atmosphere is 2.3 W m-2 (uncertainty: 0.7–4.3 W m-230 ) in the Plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network (AERONET) observations. The BC forcings are attributed to emissions from different regions.

black carbon↗
DOE OSTI2015

Claudin-3 expression in radiation-exposed rat models: A potential marker for radiation-induced intestinal barrier failure

Highlights: • Irradiation increased intestinal bacterial translocation, accompanied by claudin protein expression in rats. • Neurotensin decreased the bacterial translocation and restored claudin-3 expression. • Claudin-3 can be used as a marker in evaluating radiation induced intestinal injury. - Abstract: The molecular events leading to radiation-induced intestinal barrier failure are not well known. The influence of the expression of claudin proteins in the presence and absence of neurotensin was investigated in radiation-exposed rat intestinal epithelium. Wistar rats were randomly divided into control, irradiation, and irradiation + neurotensin groups, and bacterial translocation to the mesenteric lymph node and expression of claudins were determined. Irradiation led to intestinal barrier failure as demonstrated by significant bacterial translocation. In irradiated terminal ilea, expression of claudin-3 and claudin-4 was significantly decreased, and claudin-2 expression was increased. Administration of neurotensin significantly reduced bacterial translocation and restored the structure of the villi as seen by histologic examination. Among the three subtype of claudins, only claudin-3 expression was restored. These results suggest that the therapeutic effect of neurotensin on the disruption of the intestinal barrier is associated with claudin-3 alteration and that claudin-3 could be used as a marker in evaluating radiation-induced intestinal injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

A Dose-Volume Analysis of Radiation Pneumonitis in Non-Small Cell Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy

Purpose: To examine the rates and risk factors of radiation pneumonitis (RP) in non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT). Methods and Materials: Dosimetry records for 251 patients with lymph node-negative Stage I-IIB NSCLC and no prior chest radiation therapy (RT) treated with SBRT were reviewed. Patients were coded on the basis of the presence of at least Grade (G) 2 RP using the Common Toxicity Criteria version 2 criteria. Radiation doses, V5, V10, V20, and mean lung dose (MLD) data points were extracted from the dose-volume histogram (DVH). Results: Median PTV volume was 48 cc. Median prescribed radiation dose was 60 Gy delivered in three fractions to the 80% isodose line. Median age at treatment was 74 years. Median follow-up was 17 months. RP was reported after treatment of 42 lesions: G1 in 19 (8%), G2 in 17 (7%), G3 in 5 (2%), and G4 in 1 (0.4%). Total lung DVHs were available for 143 patients. For evaluable patients, median MLD, V5, V10, and V20 were 4.1 Gy, 20%, 12%, and 4%, respectively. Median MLDs were 4 Gy and 5 Gy for G0-1 and G2-4 groups, respectively (p = 0.14); median V5 was 20% for G0-1 and 24% for G2-4 (p = 0.70); median V10 was 12% in G0-1 and 16% in G2-4 (p = 0.08), and median V20 was 4% in G0-1 and 6.6% in G2-4 (p = 0.05). G2-4 RP was noted in 4.3% of patients with MLD {<=}4 Gy compared with 17.6% of patients with MLD >4 Gy (p = 0.02), and in 4.3% of patients with V20 {<=}4% compared with 16.4% of patients with V20 >4% (p = 0.03). Conclusion: Overall rate of G2-4 RP in our population treated with SBRT was 9.4%. Development of symptomatic RP in this series correlated with MLD and V20.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

The American Society for Radiation Oncology's 2010 Core Physics Curriculum for Radiation Oncology Residents

Purpose: In 2004, the American Society for Radiation Oncology (ASTRO) published its first physics education curriculum for residents, which was updated in 2007. A committee composed of physicists and physicians from various residency program teaching institutions was reconvened again to update the curriculum in 2009. Methods and Materials: Members of this committee have associations with ASTRO, the American Association of Physicists in Medicine, the Association of Residents in Radiation Oncology, the American Board of Radiology (ABR), and the American College of Radiology. Members reviewed and updated assigned subjects from the last curriculum. The updated curriculum was carefully reviewed by a representative from the ABR and other physics and clinical experts. Results: The new curriculum resulted in a recommended 56-h course, excluding initial orientation. Learning objectives are provided for each subject area, and a detailed outline of material to be covered is given for each lecture hour. Some recent changes in the curriculum include the addition of Radiation Incidents and Bioterrorism Response Training as a subject and updates that reflect new treatment techniques and modalities in a number of core subjects. The new curriculum was approved by the ASTRO board in April 2010. We anticipate that physicists will use this curriculum for structuring their teaching programs, and subsequently the ABR will adopt this educational program for its written examination. Currently, the American College of Radiology uses the ASTRO curriculum for their training examination topics. In addition to the curriculum, the committee updated suggested references and the glossary. Conclusions: The ASTRO physics education curriculum for radiation oncology residents has been updated. To ensure continued commitment to a current and relevant curriculum, the subject matter will be updated again in 2 years.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy

Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models. Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free tri-iodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with {alpha}/{beta} = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion. Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D{sub 50} estimated from the models was approximately 44 Gy. Conclusions: The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Combining Physical and Biologic Parameters to Predict Radiation-Induced Lung Toxicity in Patients With Non-Small-Cell Lung Cancer Treated With Definitive Radiation Therapy

Purpose: To investigate the plasma dynamics of 5 proinflammatory/fibrogenic cytokines, including interleukin-1beta (IL-1{beta}), IL-6, IL-8, tumor necrosis factor alpha (TNF-{alpha}), and transforming growth factor beta1 (TGF-{beta}1) to ascertain their value in predicting radiation-induced lung toxicity (RILT), both individually and in combination with physical dosimetric parameters. Methods and Materials: Treatments of patients receiving definitive conventionally fractionated radiation therapy (RT) on clinical trial for inoperable stages I-III lung cancer were prospectively evaluated. Circulating cytokine levels were measured prior to and at weeks 2 and 4 during RT. The primary endpoint was symptomatic RILT, defined as grade 2 and higher radiation pneumonitis or symptomatic pulmonary fibrosis. Minimum follow-up was 18 months. Results: Of 58 eligible patients, 10 (17.2%) patients developed RILT. Lower pretreatment IL-8 levels were significantly correlated with development of RILT, while radiation-induced elevations of TGF-ss1 were weakly correlated with RILT. Significant correlations were not found for any of the remaining 3 cytokines or for any clinical or dosimetric parameters. Using receiver operator characteristic curves for predictive risk assessment modeling, we found both individual cytokines and dosimetric parameters were poor independent predictors of RILT. However, combining IL-8, TGF-ss1, and mean lung dose into a single model yielded an improved predictive ability (P<.001) compared to either variable alone. Conclusions: Combining inflammatory cytokines with physical dosimetric factors may provide a more accurate model for RILT prediction. Future study with a larger number of cases and events is needed to validate such findings.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Retrospective Cohort Study of Bronchial Doses and Radiation-Induced Atelectasis After Stereotactic Body Radiation Therapy of Lung Tumors Located Close to the Bronchial Tree

Purpose: To evaluate the dose–response relationship between radiation-induced atelectasis after stereotactic body radiation therapy (SBRT) and bronchial dose. Methods and Materials: Seventy-four patients treated with SBRT for tumors close to main, lobar, or segmental bronchi were selected. The association between incidence of atelectasis and bronchial dose parameters (maximum point-dose and minimum dose to the high-dose bronchial volume [ranging from 0.1 cm{sup 3} up to 2.0 cm{sup 3}]) was statistically evaluated with survival analysis models. Results: Prescribed doses varied between 4 and 20 Gy per fraction in 2-5 fractions. Eighteen patients (24.3%) developed atelectasis considered to be radiation-induced. Statistical analysis showed a significant correlation between the incidence of radiation-induced atelectasis and minimum dose to the high-dose bronchial volumes, of which 0.1 cm{sup 3} (D{sub 0.1cm3}) was used for further analysis. The median value of D{sub 0.1cm3} (α/β = 3 Gy) was EQD{sub 2,LQ} = 147 Gy{sub 3} (range, 20-293 Gy{sub 3}). For patients who developed atelectasis the median value was EQD{sub 2,LQ} = 210 Gy{sub 3}, and for patients who did not develop atelectasis, EQD{sub 2,LQ} = 105 Gy{sub 3}. Median time from treatment to development of atelectasis was 8.0 months (range, 1.1-30.1 months). Conclusion: In this retrospective study a significant dose–response relationship between the incidence of atelectasis and the dose to the high-dose volume of the bronchi is shown.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Lung Texture in Serial Thoracic Computed Tomography Scans: Correlation of Radiomics-based Features With Radiation Therapy Dose and Radiation Pneumonitis Development

Purpose: To assess the relationship between radiation dose and change in a set of mathematical intensity- and texture-based features and to determine the ability of texture analysis to identify patients who develop radiation pneumonitis (RP). Methods and Materials: A total of 106 patients who received radiation therapy (RT) for esophageal cancer were retrospectively identified under institutional review board approval. For each patient, diagnostic computed tomography (CT) scans were acquired before (0-168 days) and after (5-120 days) RT, and a treatment planning CT scan with an associated dose map was obtained. 32- × 32-pixel regions of interest (ROIs) were randomly identified in the lungs of each pre-RT scan. ROIs were subsequently mapped to the post-RT scan and the planning scan dose map by using deformable image registration. The changes in 20 feature values (ΔFV) between pre- and post-RT scan ROIs were calculated. Regression modeling and analysis of variance were used to test the relationships between ΔFV, mean ROI dose, and development of grade ≥2 RP. Area under the receiver operating characteristic curve (AUC) was calculated to determine each feature's ability to distinguish between patients with and those without RP. A classifier was constructed to determine whether 2- or 3-feature combinations could improve RP distinction. Results: For all 20 features, a significant ΔFV was observed with increasing radiation dose. Twelve features changed significantly for patients with RP. Individual texture features could discriminate between patients with and those without RP with moderate performance (AUCs from 0.49 to 0.78). Using multiple features in a classifier, AUC increased significantly (0.59-0.84). Conclusions: A relationship between dose and change in a set of image-based features was observed. For 12 features, ΔFV was significantly related to RP development. This study demonstrated the ability of radiomics to provide a quantitative, individualized measurement of patient lung tissue reaction to RT and assess RP development.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Late Side Effects After Image Guided Intensity Modulated Radiation Therapy Compared to 3D-Conformal Radiation Therapy for Prostate Cancer: Results From 2 Prospective Cohorts

Purpose: Technical developments in the field of external beam radiation therapy (RT) enabled the clinical introduction of image guided intensity modulated radiation therapy (IG-IMRT), which improved target conformity and allowed reduction of safety margins. Whether this had an impact on late toxicity levels compared to previously applied three-dimensional conformal radiation therapy (3D-CRT) is currently unknown. We analyzed late side effects after treatment with IG-IMRT or 3D-CRT, evaluating 2 prospective cohorts of men treated for localized prostate cancer to investigate the hypothesized reductions in toxicity. Methods and Materials: Patients treated with 3D-CRT (n=189) or IG-IMRT (n=242) to 78 Gy in 39 fractions were recruited from 2 Dutch randomized trials with identical toxicity scoring protocols. Late toxicity (>90 days after treatment) was derived from self-assessment questionnaires and case report forms, according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG-EORTC) scoring criteria. Grade ≥2 endpoints included gastrointestinal (GI) rectal bleeding, increased stool frequency, discomfort, rectal incontinence, proctitis, and genitourinary (GU) obstruction, increased urinary frequency, nocturia, urinary incontinence, and dysuria. The Cox proportional hazards regression model was used to compare grade ≥2 toxicities between both techniques, adjusting for other modifying factors. Results: The 5-year cumulative incidence of grade ≥2 GI toxicity was 24.9% for IG-IMRT and 37.6% following 3D-CRT (adjusted hazard ratio [HR]: 0.59, P=.005), with significant reductions in proctitis (HR: 0.37, P=.047) and increased stool frequency (HR: 0.23, P<.001). GU grade ≥2 toxicity levels at 5 years were comparable with 46.2% and 36.4% following IG-IMRT and 3D-CRT, respectively (adjusted HR: 1.19, P=.33). Other strong predictors (P<.01) of grade ≥2 late toxicity were baseline complaints, acute toxicity, and age. Conclusions: Treatment with IG-IMRT reduced the risk of late grade ≥2 complications, whereas GU toxicities remained comparable. This clinically relevant observation demonstrates that IMRT and image-guidance should therefore be the preferred treatment option, provided that margin reduction is implemented with caution.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

The Effect of Biologically Effective Dose and Radiation Treatment Schedule on Overall Survival in Stage I Non-Small Cell Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy

Purpose: To determine the effect of biologically effective dose (BED{sub 10}) and radiation treatment schedule on overall survival (OS) in patients with early-stage non-small cell lung cancer (NSCLC) undergoing stereotactic body radiation therapy (SBRT). Methods and Materials: Using data from 65 treatment centers in the United States, we retrospectively reviewed the records of T1-2 N0 NSCLC patients undergoing SBRT alone from 2006 to 2014. Biologically relevant covariates, including dose per fraction, number of fractions, and time between fractions, were used to quantify BED{sub 10} and radiation treatment schedule. The linear-quadratic equation was used to calculate BED{sub 10} and to generate a dichotomous dose variable of <105 Gy versus ≥105 Gy BED{sub 10}. The primary outcome was OS. We used the Kaplan-Meier method, the log–rank test, and Cox proportional hazards regression with propensity score matching to determine whether prescription BED{sub 10} was associated with OS. Results: We identified 747 patients who met inclusion criteria. The median BED{sub 10} was 132 Gy, and 59 (7.7%) had consecutive-day fractions. Median follow-up was 41 months, and 452 patients (60.5%) had died by the conclusion of the study. The 581 patients receiving ≥105 Gy BED{sub 10} had a median survival of 28 months, whereas the 166 patients receiving <105 Gy BED{sub 10} had a median survival of 22 months (log–rank, P=.01). Radiation treatment schedule was not a significant predictor of OS on univariable analysis. After adjusting for T stage, sex, tumor histology, and Eastern Cooperative Oncology Group performance status, BED{sub 10} ≥105 Gy versus <105 Gy remained significantly associated with improved OS (hazard ratio 0.78, 95% confidence interval 0.62-0.98, P=.03). Propensity score matching on imbalanced variables within high- and low-dose cohorts confirmed a survival benefit with higher prescription dose. Conclusions: We found that dose escalation to 105 Gy BED{sub 10} and beyond may improve survival in NSCLC patients treated with SBRT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Prognostic Factors and Patterns of Locoregional Failure After Surgical Resection in Patients With Cholangiocarcinoma Without Adjuvant Radiation Therapy: Optimal Field Design for Adjuvant Radiation Therapy

Purpose: To identify prognostic factors and patterns of local failure in patients with cholangiocarcinoma (CCA), after surgical resection in the absence of adjuvant radiation, for optimal definition of target volumes encompassing the majority of local recurrences. Methods and Materials: A chart review was performed in patients who underwent resection for primary CCA (intrahepatic, hilar, and distal) between 1999 and 2014. Local failure was defined as recurrence in a theoretical reasonable postoperative radiation volume. This includes the cut surface of liver, biliary anastomosis, hilum, portal nodes, celiac nodes, peri-pancreatic nodes, gastro-hepatic nodes, and retroperitoneal nodes. Patients who received adjuvant radiation were excluded. Results: A total of 189 patients underwent surgical resection for CCA, of whom 145 patients had sufficient follow-up. Median follow-up was 41.6 months (95% confidence interval 35.4-48.7 months). Of the 145 cases, 102 were intrahepatic and 43 were hilar/distal CCA. Adjuvant chemotherapy was given in 38 cases (26%), of which 20 (54%) were gemcitabine-based. Eighty-six patients (59%) had a documented recurrence, of whom 44 (51%) had a locoregional component. Among patients who had a recurrence, 23 (27%) had a recurrence at the biliary anastomosis and/or cut liver surface. Twenty-eight patients (32.6%) had a recurrence in the regional lymph nodes, most prevalent in the portal (16.3%) and retroperitoneal (17.4%) lymph nodes. Univariable analysis identified tumor size, any vascular invasion, presence of satellites, stage/nodal status, and receipt of chemotherapy as significant prognostic factors of overall recurrence among intrahepatic patients. Presence of satellites, and stage 3/Nx status remained statistically significant in multivariable modeling. Conclusions: The areas at highest risk for locoregional recurrence after surgical resection for primary CCA are the biliary anastomosis/cut liver surface, portal lymph nodes, and retroperitoneal lymph nodes. Although these results need to be validated, adjuvant radiation should possibly cover these areas to maximize locoregional control.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

The Role of Radiation Therapy in Patients With Relapsed or Refractory Hodgkin Lymphoma: Guidelines From the International Lymphoma Radiation Oncology Group

Relapsed and refractory Hodgkin lymphoma (HL) challenges clinicians to devise treatment strategies that are effective and safe. This problem is particularly prominent in an era when de-escalation trials are designed to minimize therapeutic toxicities in both early- and advanced-stage disease. Radiation therapy is the single most effective treatment modality for HL, and its integration into salvage regimens, or its independent use in select patients, must be understood to maximize our success in treating these patients. The complexity of treating relapsed or refractory HL derives from the spectrum of primary treatment approaches currently in use that creates heterogeneity in both treatment exposure and the potential toxicities of salvage therapy. Patients can have relapsed or refractory disease after limited or aggressive primary therapy (with or without radiation therapy), at early or delayed time points, with limited or extensive disease volumes, and with varying degrees of residual morbidity from primary therapy. Their response to salvage systemic therapy can be partial or complete, and the use of consolidative stem cell transplantation is variably applied. New biologics and immunotherapeutic approaches have broadened but also complicated salvage treatment approaches. Through all of this, radiation therapy remains an integral component of treatment for many patients, but it must be used effectively and judiciously. The purpose of this review is to describe the different treatment scenarios and provide guidance for radiation dose, volume, and timing in patients with relapsed or refractory HL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Behavioral Determinants of Canadian Radiation Oncologists’ Use of Single Fraction Palliative Radiation Therapy for Uncomplicated Bone Metastases

A mainstay therapy for pain relief from uncomplicated bone metastases is external beam radiation therapy. Single fraction radiation therapy (SFRT) is more convenient and cost-effective, causes fewer acute side effects, and is equivalent to multiple fraction radiation therapy for pain relief. Despite these advantages, radiation oncologists seldom prescribe SFRT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

Tensile behavior of dual-phase titanium alloys under high-intensity proton beam exposure: radiation-induced omega phase transformation in Ti-6Al-4V

A high-intensity proton beam exposure with 181 MeV energy has been conducted at Brookhaven Linac Isotope Producer facility on various material specimens for accelerator targetry applications, including titanium alloys as a beam window material. The radiation damage level of the analyzed capsule was 0.25 dpa at the beam center region with an irradiation temperature around 120 oC. Tensile tests showed increased hardness and a large decrease in ductility for the dual a+ß-phase Ti-6Al-4V Grade-5 and Grade-23 extra low interstitial alloys, with the near a-phase Ti-3Al-2.5V Grade-9 alloy still exhibiting uniform elongation of a few % after irradiation. Transmission Electron Microscope analyses on Ti-6Al-4V indicated clear evidence of a high-density of defect clusters with size less than 2 nm in each a-phase grain. The ß-phase grains did not contain any visible defects such as loops or black dots, while the diffraction patterns clearly indicated ?-phase precipitation in an advanced formation stage. The radiation-induced ?-phase transformation in the ß-phase could lead to greater loss of ductility in Ti-6Al-4V alloys in comparison with Ti-3Al-2.5V alloy with less ß-phase.google scho

Tensile Test, titanium, acclerator, proton beam↗
DOE OSTI2025

Potential Effects of Climate Change and Solar Radiation Modification on Renewable Energy Resources

Solar radiation modification (SRM) is a possible deliberate approach to decrease or reflect incoming solar radiation with the goal of reducing global temperatures, which have increased over the last decades due to high atmospheric greenhouse gas concentrations. Stratospheric aerosol injection, specifically, has shown potential for successfully reducing global temperatures in climate model simulations. Despite the growing literature in the areas of climate change and SRM, their combined effects on renewable energy generation, a climate change mitigation strategy, have not been addressed. In this review paper, we synthesize previous literature on the possible effects of climate change and SRM on renewable energy resources (i.e., wind energy, solar energy, biomass energy, and hydropower), review the status of climate change and SRM research, and explore potential effects of SRM on renewable energy primarily in the Continental United States (CONUS), but with global perspectives as well. We discuss the research challenges and impacts of SRM on renewable energy and conclude by discussing the potential implications of SRM for renewables for SRM governance and policy. This work is not advocating for or against SRM. It is highlighting an important potential impact for future decision makers.

Kumler, Andrew [National Renewable Energy Laborato↗
DOE OSTI2021

Radiation-Enhanced Anion Transport in Hematite

The influence of radiation-induced (1 MeV energy H+ to ~0.1 dpa at 450°C), non-equilibrium point defect populations on mass transport is studied with an integrated campaign of experimental and theoretical methods. Using epitaxial thin films of hematite with embedded 18O tracer layers and nanoscale atom probe tomography measurements, it is shown that anion self-diffusion is enhanced by at least 2 orders of magnitude under irradiation compared to thermal diffusion alone. Complementary scanning transmission electron microscopy of vacuum annealed specimens, reveals associated microstructural changes in the oxide films, including local phase transformation to Fe3O4 and the development of nanoscale voids from vacancy coalescence. Point defect formation and migration energies were computed from density functional theory and applied within the context of chemical rate theory to analyze contributions from both interstitial and vacancy mechanisms to self-diffusion in thermal and irradiation conditions. Comparisons are made between calculated, literature and newly measured self-diffusion values, revealing good agreement on the magnitude of radiation-enhanced anion diffusion. Further, the model suggests a transition from vacancy to interstitialcy mechanisms at low temperatures and high oxygen activity, consistent with the varied activation energies reported from prior studies.

iron oxides, isotopic tracers, atom probe tomograp↗