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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 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Insights into riming and aggregation processes as revealed by aircraft, radar, and disdrometer observations for a 27 April 2011 widespread precipitation event: Insights into Riming and Aggregation

Our study presents aircraft spiral ascent and descent observations intercepting a transition to riming processes during widespread stratiform precipitation. The sequence is documented using collocated scanning and profiling radar, including longer-wavelength dual polarization measurements and shorter-wavelength Doppler spectra. Riming regions are supported using aircraft measurements recording elevated liquid water concentrations, spherical particle shapes, and saturation with respect to water. Profiling cloud radar observations indicate riming regions during the event as having increasing particle fall speeds, rapid time-height changes, and bimodalities in Doppler spectra. These particular riming signatures are coupled to scanning dual polarization radar observations of higher differential reflectivity (ZDR) aloft. Moreover, reduced melting layer enhancements and delayed radar bright-band signatures in the column are also observed during riming periods, most notably with the profiling radar observations. The bimodal cloud radar Doppler spectra captured near riming zones indicate two time-height spectral ice peaks, one rimed particle peak, and one peak associated with pristine ice needle generation and/or growth between -4°C and -7°C also sampled by aircraft probes. We observe this pristine needle population near the rimed particle region which gives a partial explanation for the enhanced ZDR. The riming signatures aloft and radar measurements within the melting level are weakly lag correlated (r~0.6) with smaller median drop sizes at the surface, as compared with later times when aggregation of larger particle sizes was believed dominant.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Dose‐response relationships between internally‐deposited uranium and select health outcomes in gaseous diffusion plant workers, 1948‐2011

Objective To examine dose‐response relationships between internal uranium exposures and select outcomes among a cohort of uranium enrichment workers. Methods Cox regression was conducted to examine associations between selected health outcomes and cumulative internal uranium with consideration for external ionizing radiation, work‐related medical X‐rays and contaminant radionuclides technetium ( 99 Tc) and plutonium ( 239 Pu) as potential confounders. Results Elevated and monotonically increasing mortality risks were observed for kidney cancer, chronic renal diseases, and multiple myeloma, and the association with internal uranium absorbed organ dose was statistically significant for multiple myeloma. Adjustment for potential confounders had minimal impact on the risk estimates. Conclusion Kidney cancer, chronic renal disease, and multiple myeloma mortality risks were elevated with increasing internal uranium absorbed organ dose. The findings add to evidence of an association between internal exposure to uranium and cancer. Future investigation includes a study of cancer incidence in this cohort.

Yiin, James H.↗
DOE OSTI2012

Application of Surface Analysis Methods to Nanomaterials: Summaryof ISO/TC 201 Technical Report: ISO 14187:2011 -Surface Chemical Analysis- Characterization of Nanomaterials

ISO Technical Report (TR) 14187 provides an introduction to (and examples of) the information that can be obtained about nanostructured materials using surface-analysis tools. In addition, both general issues and challenges associated with characterising nanostructured materials and the specific opportunities and challenges associated with individual analytical methods are identified. As the size of objects or components of materials approaches a few nanometres, the distinctions among 'bulk', 'surface' and 'particle' analysis blur. This Technical Report focuses on issues specifically relevant to surface chemical analysis of nanostructured materials. The report considers a variety of analysis methods but focuses on techniques that are in the domain of ISO/TC 201 including Auger electron spectroscopy, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and scanning probe microscopy. Measurements of nanoparticle surface properties such as surface potential that are often made in a solution are not discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2012

A Surgeon's View on Endarterectomy and Stenting in 2011: Lest We Forget, It's All About Preventing Stroke

It has been nearly 60 years since Felix Eastcott published his seminal paper on carotid reconstruction, which paved the way for carotid endarterectomy (CEA) and then carotid artery stenting (CAS) to assume prominent roles in the prevention of stroke. Yet the ensuing 60 years has witnessed repeated cycles of challenges to practice, professional mistrust, conflicts of interest, dogmatic retention of traditional management strategies, inappropriate corporate interventions, and a general failure to adapt to new evidence. Even the performance of large-scale randomised trials has been associated with rancour and a lack of consensus. This article reviews the history of invasive interventions in the treatment of carotid disease and makes a plea to both the surgical and interventional communities that the fundamental priority must always be the prevention of stroke. It concludes with an appeal for colleagues to collaborate to determine how best to treat patients during the hyperacute period after the onset of symptoms and to identify a smaller cohort of asymptomatic patients who are truly at high risk for stroke in whom to target CAS or CEA.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Unconventional Energy Resources: 2011 Review

This report contains nine unconventional energy resource commodity summaries prepared by committees of the Energy Minerals Division (EMD) of the American Association of Petroleum Geologists. Unconventional energy resources, as used in this report, are those energy resources that do not occur in discrete oil or gas reservoirs held in structural or stratigraphic traps in sedimentary basins. These resources include coal, coalbed methane, gas hydrates, tight gas sands, gas shale and shale oil, geothermal resources, oil sands, oil shale, and uranium resources. Current U.S. and global research and development activities are summarized for each unconventional energy commodity in the topical sections of this report. Coal and uranium are expected to supply a significant portion of the world's energy mix in coming years. Coalbed methane continues to supply about 9% of the U.S. gas production and exploration is expanding in other countries. Recently, natural gas produced from shale and low-permeability (tight) sandstone has made a significant contribution to the energy supply of the United States and is an increasing target for exploration around the world. In addition, oil from shale and heavy oil from sandstone are a new exploration focus in many areas (including the Green River area of Wyoming and northern Alberta). In recent years, research in the areas of geothermal energy sources and gas hydrates has continued to advance. Reviews of the current research and the stages of development of these unconventional energy resources are described in the various sections of this report.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2011

2011 Status of the Automatic Alignment System for the National Ignition Facility

Automated alignment for the National Ignition Facility (NIF) is accomplished using a large-scale parallel control system that directs 192 laser beams along the 300-m optical path. The beams are then focused down to a 50-micron spot in the middle of the target chamber. The entire process is completed in less than 50 minutes. The alignment system commands 9,000 stepping motors for highly accurate adjustment of mirrors and other optics. 41 control loops per beamline perform parallel processing services running on a LINUX cluster to analyze high-resolution images of the beams and their references. This paper describes the status the NIF automatic alignment system and the challenges encountered as NIF development has transitioned from building the laser, to becoming a research project supporting a 24 hour, 7 day laser facility. NIF is now a continuously operated system where performance monitoring is increasingly more critical for operation, maintenance, and commissioning tasks. Equipment wear and the effects of high energy neutrons from fusion experiments are issues which alter alignment efficiency and accuracy. New sensors needing automatic alignment assistance are common. System modifications to improve efficiency and accuracy are prevalent. Handling these evolving alignment and maintenance needs while minimizing the impact on NIF experiment schedule is expected to be an on-going challenge for the planned 30 year operational life of NIF.

42 ENGINEERING↗
DOE OSTI2012

Response to “The value of CCS public opinion research” by Fleishman et al. (2011)

Fleishman et al have submitted a critique of a paper previously published in this same journal by Malone, Dooley and Bradbury. This submission represents our response to the critique by Fleishman et al. This submission reiterates our position that polling the public writ large as to the value of CCS research is not a technically sound way of understanding how CCS technologies might deploy in the future.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Quality Assurance Peer Review Chart Rounds in 2011: A Survey of Academic Institutions in the United States

Purpose: In light of concerns regarding the quality of radiation treatment delivery, we surveyed the practice of quality assurance peer review chart rounds at American academic institutions. Methods and Materials: An anonymous web-based survey was sent to the chief resident of each institution across the United States. Results: The response rate was 80% (57/71). The median amount of time spent per patient was 2.7 minutes (range, 0.6-14.4). The mean attendance by senior physicians and residents was 73% and 93%, respectively. A physicist was consistently present at peer review rounds in 66% of departments. There was a close association between attendance by senior physicians and departmental organization: in departments with protected time policies, good attendance was 81% vs. 31% without protected time (p = 0.001), and in departments that documented attendance, attending presence was 69% vs. 29% in departments without documentation (p < 0.05). More than 80% of institutions peer review all external beam therapy courses; however, rates were much lower for other modalities (radiosurgery 58%, brachytherapy 40%-47%). Patient history, chart documentation, and dose prescription were always peer reviewed in >75% of institutions, whereas dosimetric details (beams, wedges), isodose coverage, intensity-modulated radiation therapy constraints, and dose-volume histograms were always peer reviewed in 63%, 59%, 42%, and 50% of cases, respectively. Chart rounds led to both minor (defined as a small multileaf collimator change/repeated port film) and major (change to dose prescription or replan with dosimetry) treatment changes. Whereas at the majority of institutions changes were rare (<10% of cases), 39% and 11% of institutions reported that minor and major changes, respectively, were made to more than 10% of cases. Conclusion: The implementation of peer review chart rounds seems inconsistent across American academic institutions. Brachytherapy and radiosurgical procedures are rarely reviewed. Attendance by senior physicians is variable, but it improves when scheduling clashes are avoided. The potential effect of a more thorough quality assurance peer review on patient outcomes is not known.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Data mining in earth system science (DMESS 2011).

From field-scale measurements to global climate simulations and remote sensing, the growing body of very large and long time series Earth science data are increasingly difficult to analyze, visualize, and interpret. Data mining, information theoretic, and machine learning techniques - such as cluster analysis, singular value decomposition, block entropy, Fourier and wavelet analysis, phase-space reconstruction, and artificial neural networks - are being applied to problems of segmentation, feature extraction, change detection, model-data comparison, and model validation. The size and complexity of Earth science data exceed the limits of most analysis tools and the capacities of desktop computers. New scalable analysis and visualization tools, running on parallel cluster computers and supercomputers, are required to analyze data of this magnitude. This workshop will demonstrate how data mining techniques are applied in the Earth sciences and describe innovative computer science methods that support analysis and discovery in the Earth sciences.

54 ENVIRONMENTAL SCIENCES↗