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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Investigating the ecological fallacy through sampling distributions constructed from finite populations

Correlation coefficients and linear regression values computed from group averages can differ from correlation coefficients and linear regression values computed using individual scores. This observation known as the ecological fallacy often assumes that all the individual scores are available from a population. In many situations, one must use a sample from the larger population. In such cases, the computed correlation coefficient and linear regression values will depend on the sample that is chosen and the underlying sampling distribution. The sampling distribution of correlation coefficients and linear regression values for group averages will be identical to the sampling distribution for individuals for normally distributed variables for random samples drawn from infinitely large continuous distributions. However, data that is acquired in practice is often acquired when sampling without replacement from a finite population. Our objective is to demonstrate through Monte Carlo simulations that the sampling distributions for correlation and linear regression will also be similar for individuals and group averages when sampling without replacement from normally distributed variables. These simulations suggest that when a random sample from a population is selected, the correlation coefficients and linear regression values computed from individual scores will not be more accurate in estimating the entire population values compared to samples when group averages are used as long as the sample size is the same.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilution system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Successes and Lessons Learned in the Design, Construction and Use of a Tool for Sampling the WR-1 Reactor Core - 1900z

Whiteshell Laboratories, located in Manitoba, Canada, provided research facilities for the Canadian nuclear industry since the early 1960's. The facility was centered on an organically cooled, heavy water moderated nuclear reactor in the world, Whiteshell Reactor 1 (WR-1). WR-1 was safely shut down in 1985, de-fueled and drained, and has been in a safe Storage with Surveillance (Deferred Decommissioning) state until present day. In support of an Environmental Assessment for proposed In Situ Decommissioning of WR-1, detailed characterization information regarding the reactor core components (calandria, calandria tubes, pressure tubes) was necessary to verify inventory estimates and neutron activation models produced circa 1992. The Fuel Channels of WR-1 (pressure tubes) were expected to be the most activated components of the reactor core, and to account for about 60% of the reactor core inventory. The interior surface of the fuel channel is also the most readily accessible surface within the reactor core. As such the decision was made to collect a sample of one of each of 3 Fuel Channel material types (Stainless Steel, Zr-2.5Nb, Ozhenite) for comparison to modelled estimates of neutron activation of various core materials. The expected dose rates from the samples were between 5 and 100 mSv (500-10,000 mrem) on contact based on a 200 mg sample. Sampling the Fuel Channels required verification the Fuel Channel was drained of organic coolant, removal of residual organic coolant from the Fuel Channel wall, removal of material from the interior surface of the Fuel Channel at the centerline of flux (∼25' below the operator position), and extraction of that material from the core. Several options for existing tooling and technologies, including hydraulic scrapers, and horizontal drill technologies, were looked at for their applicability to WR-1. While suitable approaches to higher radiation field sample collection, they were overly complex, costly and time consuming for the configuration at WR-1. In an effort to reduce costs, and to simplify the sampling process, a specialized and simple tool was developed to mechanically scrape a small sample of the interior wall of the Fuel Channels, collect the sample into a vial, and remove the sample from the core for analysis. The tool was designed, constructed, tested and implemented in the field entirely by Canadian Nuclear Laboratories Staff. The tool required no powered components, or electronic guidance or measurements; and was designed and constructed for a fraction of the cost of other commercially available technologies for sample collection within reactor cores. The samples were successfully collected without any injuries, contamination events or equipment failures. The tool remains operational in the event additional sampling is required. This paper provides additional details of the design, construction, testing and use of the tool and the successes and lessons learned during the various stages of design and implementation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

K‐band luminosity–environment relation in three different galaxy samples of the Sloan Digital Sky Survey III

The aim of this work is to examine the environmental dependence of K‐band luminosity in the Main, Low Redshift (LOWZ), and Constant Mass (CMASS) galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10). Overall, the environmental dependence of K‐band luminosity is very mild. In two volume‐limited Main samples with the luminosity −20.5 ≤ M r ≤ −18.5 and −22.5 ≤ M r ≤ −20.5, respectively, we find that the environmental dependence of K‐band luminosity in the luminous volume‐limited Main galaxy sample still can be observed, but this dependence in the faint volume‐limited Main galaxy sample is very weak. Considering the disadvantages of the use of volume‐limited samples, we apply the apparent magnitude‐limited Main galaxy sample, divide the Main galaxy sample of the SDSS DR10 into subsamples with a redshift binning size of Δ z =0.01, and then analyze the environmental dependence of K‐band luminosity of subsamples in each redshift bin. Such a method also is used in the LOWZ and CMASS galaxy samples. K‐band luminosity of the Main galaxies shows substantial correlation with the local environment in many redshift bins. In the LOWZ galaxy sample, K‐band luminosity of galaxies shows substantial correlation with the local environment only in the redshift region 0.16 ≤ z ≤ 0.21, while K‐band luminosity of CMASS galaxy sample is only weakly correlated with the local environment. Statistical results also show that in the apparent magnitude‐limited main galaxy sample and the LOWZ galaxy sample, environmental dependence of K‐band luminosity becomes weak with increasing redshift.

Deng, X. ‐F.↗
DOE OSTI2015

Low surface brightness galaxies selected from the 40% sky area of the ALFALFA H i Survey. I. Sample and statistical properties

The population of low surface brightness (LSB) galaxies, which are objects with central surface brightnesses at least one magnitude fainter than the night sky, is crucial for understanding the extremes of galactic formation and evolution of the universe. As LSB galaxies are mostly rich in gas (H i), the α.40 Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) sample is one of the best survey combinations to select a sample of them in the local universe. Since the sky backgrounds are systematically overestimated for galactic images by the SDSS photometric pipeline, particularly for luminous galaxies or galaxies with extended LSB outskirts, in this paper, we above all estimated the sky backgrounds of SDSS images accurately in both the g and r bands for each galaxy in the α.40 SDSS DR7 sample, using a precise method of sky subtraction. Once subtracting the sky background, we did surface photometry with the Kron elliptical aperture using the SExtractor software and fitted geometric parameters with an exponential profile model using the Galfit software for each galactic image in the α.40 SDSS DR7 sample. Based on the photometric and geometric results, we further calculated the B-band central surface brightness, μ{sub 0}(B), for each galaxy and ultimately defined a sample of LSB galaxies consisting of 1129 galaxies with μ{sub 0}(B) > 22.5 mag arcsec{sup −2} and the axis ratio b/a > 0.3 from the 12,423 α.40 SDSS DR7 galaxies. This H i-selected sample of LSB galaxies is a relatively unbiased sample of gas-rich and disk-dominated LSB galaxies, which is complete both in H i observation and the optical magnitude within the limit of the SDSS DR7 photometric survey. This LSB galactic sample spans from 22.5 to 28.3 in μ{sub 0}(B) with a fraction of 4% fainter than 25.0 mag arcsec{sup −2} in B-band central surface brightness and distributes from −27.0 to −12.3 mag in absolute magnitude in the B band (M(B)), including the 43 faintest galaxies (M(B) > −17.3 mag). This sample is a blue LSB galactic sample, of which 98% are bluer than 0.75 mag in B–V color. As for 21 cm H i properties, our LSB galactic sample has a median M{sub H i}/L{sub B} = 0.87, and a large portion (95%) has high mass of H i (M(H i) > 10{sup 7.7}M⊙), which supports galaxies in this LSB galactic sample being mostly gas-rich. Additionally, we statistically investigated the environment of our LSB galaxies and found that up to 92% of the total LSB galaxies have less than eight neighboring galaxies, which provides strong evidence that LSB galaxies prefer to reside in the low-density environment.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of different material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken prior to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

The Effect of Rolling As-Cast and Homogenized U-10Mo Samples on the Microstructure Development and Recovery Curves

Over the past several years Pacific Northwest National Laboratory (PNNL) has been actively involved in supporting the U.S. Department of Energy National Nuclear Security Administration Office of Material Management and Minimization (formerly Global Threat Reduction Initiative). The U.S. High- Power Research Reactor (USHPRR) project is developing alternatives to existing highly enriched uranium alloy fuel to reduce the proliferation threat. One option for a high-density metal fuel is uranium alloyed with 10 wt% molybdenum (U-10Mo). Forming the U-10Mo fuel plates/foils via rolling is an effective technique and is actively being pursued as part of the baseline manufacturing process. The processing of these fuel plates requires systematic investigation/understanding of the pre- and post-rolling microstructure, end-state mechanical properties, residual stresses, and defects, their effect on the mill during processing, and eventually, their in-reactor performance. In the work documented herein, studies were conducted to determine the effect of cold and hot rolling the as-cast and homogenized U-10Mo on its microstructure and hardness. The samples were homogenized at 900°C for 48 h, then later annealed for several durations and temperatures to investigate the effect on the material’s microstructure and hardness. The rolling of the as-cast plate, both hot and cold, was observed to form a molybdenum-rich and -lean banded structure. The cold rolling was ineffective, and in some cases exacerbated the as-cast defects. The grains elongated along the rolling direction and formed a pancake shape, while the carbides fractured perpendicularly to the rolling direction and left porosity between fractured particles of UC. The subsequent annealing of these samples at sub-eutectoid temperatures led to rapid precipitation of the ' lamellar phase, mainly in the molybdenum-lean regions. Annealing the samples above the eutectoid temperature did not refine the grain size or the banded microstructure. However, annealing the samples led to quick recovery in hardness as evidenced by a drop in Vickers hardness of 20%. Hot rolling was performed at 650 and 800°C. The hot-rolling mill loads (load separation force) were approximately 40 to 50% less than the cold-rolling for the same reduction and thickness. It was observed that hot rolling the samples with 50% or more reduction in thickness were responsible for dynamic recrystallization in the hot-rolled samples and led to grain refinement. Unlike the cold-rolled samples, the hot-rolled samples did not fracture the carbides and appeared to heal the casting defects. The recovery phenomenon was similar to the cold-rolled samples above the eutectoid temperatures, but owing to the refined grain size, the precipitation of the lamellar phase was far more rapid in these samples and the hardness increased more rapidly than in the cold rolled sample when heated below the eutectoid temperature. The data generated from these rolling efforts has been used to make the process modeling efforts more robust and applicable to all USHPRR partner rolling mills. The flow stress for cold rolling the samples was determined to be between 170-190 ksi, with frictional forces between 0.2 and 0.4 for the PNNL mill. The measured roll separation forces and those simulated using finite element methods for hot and cold rolling for the PNNL rolling mill were in good agreement.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Data Validation Package June 2016 Groundwater and Surface Water Sampling at the Old and New Rifle, Colorado, Processing Sites September 2016

Sampling Period: June 14–17 and July 7, 2016. Water samples were collected from 36 locations at New Rifle and Old Rifle, Colorado, Disposal/Processing Sites. Planned monitoring locations are shown in Attachment 1, Sampling and Analysis Work Order. Duplicate samples were collected from New Rifle locations 0216 and 0855, and Old Rifle location 0655. One equipment blank was collected after decontamination of non-dedicated equipment used to collect one surface water sample. See Attachment 2, Trip Report for additional details. Sampling and analyses were conducted as specified in the Sampling and Analysis Plan for U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated, http://energy.gov/lm/downloads/sampling-and- analysis-plan-us-department-energy-office-legacy-management-sites). New Rifle Site Samples were collected at the New Rifle site from 16 monitoring wells and 7 surface locations in compliance with the December 2008 Groundwater Compliance Action Plan [GCAP] for the New Rifle, Colorado, Processing Site (LMS/RFN/S01920). Monitoring well 0216 could not be sampled in June because it was surrounded by standing water due to the high river stage from spring runoff, it was later sampled in July. Monitoring well 0635 and surface location 0322 could not be sampled because access through the elk fence along Interstate 70 has not been completed at this time. Old Rifle Site Samples were collected at the Old Rifle site from eight monitoring wells and five surface locations in compliance with the December 2001 Ground Water Compliance Action Plan for the Old Rifle, Colorado, UMTRA Project Site (GJ0-2000-177-TAR).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Soil Sample Workplan in Support of the Site 300 Explosives Waste Treatment Facility Ecological Risk Assessment Pursuant to the Hazardous Waste Facility Permit (Part V, Special Condition #14 a-f)

The Department of Toxic Substances Control issued the Final Hazardous Waste Facility Permit to Lawrence Livermore National Laboratory, Site 300 in 2017. As part of the continual process to ensure waste treatment emissions are not impacting ecological receptors, LLNL analyzed soil samples in the vicinity of the Explosive Waste Treatment Facility (EWTF) Burn Units (i.e., Burn Cage and Burn Pan) and the Detonation Pad. Soil samples were analyzed by EPA Solid Waste 846 Methods for furans, explosives, metals, and semi-volatile compounds. In all samples, furans, explosives, and semi-volatile organic compounds were not detected. Metals were detected at concentrations below background levels. This soil sample plan will sample the same four downwind areas of the Burn Units and the same downwind areas of the Detonation, as well as including four new sample locations. The four new locations will be located to the northeast and southwest of the Burn Units and Detonation (as shown in Figure 3). The constituents to be analyzed are in Tables 7 and 8. Perchlorate was not identified as a constituent of concern in the 2007 Soil Sampling Plan. However, for this plan, all soil samples will be analyzed for perchlorate. Nitrate and all CAM17 metals have been added to the sampling plan to comply with DTSC comments received in correspondence dated June 4, 2021. After completion of the sampling event, a soil sample report will be submitted to DTSC in accordance with requirements specified in the Hazardous Waste Facility Permit, Part V, Special Conditions 16 a-f. This proposed soil sampling plan will be fully implemented no later than one year after receiving DTSC approval, in accordance with the Hazardous Waste Facility Permit, Part V, Special Condition 15.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2022

Characterization of Tank 11H Samples from Tank Closure Cesium Removal 1A (TCCR 1A) Batch 1

Savannah River Mission Completion (SRMC) is currently operating the Tank Closure Cesium Removal 1A (TCCR 1A) process to remove 137 Cs from tank waste supernate using an ion exchange process. The TCCR 1A unit processes dissolved salt fed from Tank 10H through a series of ion exchange columns containing crystalline silicotitanate (CST, IONSIV TM R9120-B, 30x60) and the effluent is then discharged to Tank 11H. In support of the TCCR 1A program, SRNL analyzed samples taken from Tank 11H (without tank mixing) before, during, and at the completion of TCCR 1A Batch 1 processing. Tank 11H serves as the receipt tank for the filtered and cesium removed product from the TCCR 1A system. Processing of Batch 1 commenced on January 13, 2022 and completed on February 17, 2022, after processing approximately 70,100 gallons. A pre-production sample was collected from the heel remaining in Tank 11H just before Batch 1 processing began. In addition, five interim surface samples were collected from Tank 11H during processing, and both a surface and a variable depth sample (VDS, ~7” from tank bottom) were collected just after processing completed. Analysis of all samples included density and gamma spectroscopy, in addition to a more comprehensive suite of analytes for the pre- and post-production samples. The density of the pre-production sample was the highest of all samples measured and was then observed to decrease for the first two interim samples, followed by becoming fairly consistent for the remainder of the samples (~1.3 g/mL). The density of 1.3 g/mL is similar to the density measured for one of the three Tank 10H qualification samples (HTF-10-21-126). The 137 Cs activity was found to decrease as additional decontaminated effluent from the TCCR columns was added to Tank 11H during processing; however, an increase in activity was observed during periods of no processing which can be attributed to leaching of 137 Cs from the known solids in Tank 11H. The Cs isotope concentrations in the Tank 11H postproduction surface sample were determined to be 99.7-99.8% lower than the concentrations measured in the Tank 10H feed as measured by mass spectrometry.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

The Effect of Rolling As-Cast and Homogenized U-10Mo Samples on the Microstructure Development and Recovery Curves

Over the past several years Pacific Northwest National Laboratory (PNNL) has been actively involved in supporting the U.S. Department of Energy National Nuclear Security Administration Office of Material Management and Minimization (formerly Global Threat Reduction Initiative). The U.S. High-Power Research Reactor (USHPRR) project is developing alternatives to existing highly enriched uranium alloy fuel to reduce the proliferation threat. One option for a high-density metal fuel is uranium alloyed with 10 wt% molybdenum (U-10Mo). Forming the U-10Mo fuel plates/foils via rolling is an effective technique and is actively being pursued as part of the baseline manufacturing process. The processing of these fuel plates requires systematic investigation/understanding of the pre- and post-rolling microstructure, end-state mechanical properties, residual stresses, and defects, their effect on the mill during processing, and eventually, their in-reactor performance. In the work documented herein, studies were conducted to determine the effect of cold and hot rolling the as-cast and homogenized U-10Mo on its microstructure and hardness. The samples were homogenized at 900°C for 48 h, then later annealed for several durations and temperatures to investigate the effect on the material’s microstructure and hardness. The rolling of the as-cast plate, both hot and cold, was observed to form a molybdenum-rich and -lean banded structure. The cold rolling was ineffective, and in some cases exacerbated the as-cast defects. The grains elongated along the rolling direction and formed a pancake shape, while the carbides fractured perpendicularly to the rolling direction and left porosity between fractured particles of UC. The subsequent annealing of these samples at sub-eutectoid temperatures led to rapid precipitation of the α + γ ' lamellar phase, mainly in the molybdenum-lean regions. Annealing the samples above the eutectoid temperature did not refine the grain size or the banded microstructure. However, annealing the samples led to quick recovery in hardness as evidenced by a drop in Vickers hardness of 20%. Hot rolling was performed at 650 and 800°C. The hot-rolling mill loads (load separation force) were approximately 40 to 50% less than the cold-rolling for the same reduction and thickness. It was observed that hot rolling the samples with 50% or more reduction in thickness were responsible for dynamic recrystallization in the hot-rolled samples and led to grain refinement. Unlike the cold-rolled samples, the hot-rolled samples did not fracture the carbides and appeared to heal the casting defects. The recovery phenomenon was similar to the cold-rolled samples above the eutectoid temperatures, but owing to the refined grain size, the precipitation of the lamellar phase was far more rapid in these samples and the hardness increased more rapidly than in the cold rolled sample when heated below the eutectoid temperature. The data generated from these rolling efforts has been used to make the process modeling efforts more robust and applicable to all USHPRR partner rolling mills. The flow stress for cold rolling the samples was determined to be between 170-190 ksi, with frictional forces between 0.2 and 0.4 for the PNNL mill. The measured roll separation forces and those simulated using finite element methods for hot and cold rolling for the PNNL rolling mill were in good agreement.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV S3, HV S3A and HV-S3B Exhaust Systems

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilution system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 µm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Immunophenotype Discovery, Hierarchical Organization, and Template-Based Classification of Flow Cytometry Samples

We describe algorithms for discovering immunophenotypes from large collections of flow cytometry samples and using them to organize the samples into a hierarchy based on phenotypic similarity. The hierarchical organization is helpful for effective and robust cytometry data mining, including the creation of collections of cell populations’ characteristic of different classes of samples, robust classification, and anomaly detection. We summarize a set of samples belonging to a biological class or category with a statistically derived template for the class. Whereas individual samples are represented in terms of their cell populations (clusters), a template consists of generic meta-populations (a group of homogeneous cell populations obtained from the samples in a class) that describe key phenotypes shared among all those samples. We organize an FC data collection in a hierarchical data structure that supports the identification of immunophenotypes relevant to clinical diagnosis. A robust template-based classification scheme is also developed, but our primary focus is in the discovery of phenotypic signatures and inter-sample relationships in an FC data collection. This collective analysis approach is more efficient and robust since templates describe phenotypic signatures common to cell populations in several samples while ignoring noise and small sample-specific variations. We have applied the template-based scheme to analyze several datasets, including one representing a healthy immune system and one of acute myeloid leukemia (AML) samples. The last task is challenging due to the phenotypic heterogeneity of the several subtypes of AML. However, we identified thirteen immunophenotypes corresponding to subtypes of AML and were able to distinguish acute promyelocytic leukemia (APL) samples with the markers provided. Clinically, this is helpful since APL has a different treatment regimen from other subtypes of AML. Core algorithms used in our data analysis are available in the flowMatch package at www.bioconductor.org. It has been downloaded nearly 6,000 times since 2014.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

System and method for extracting a sample from a surface

A system and method is disclosed for extracting a sample from a sample surface. A sample is provided and a sample surface receives the sample which is deposited on the sample surface. A hydrophobic material is applied to the sample surface, and one or more devices are configured to dispense a liquid on the sample, the liquid dissolving the sample to form a dissolved sample material, and the one or more devices are configured to extract the dissolved sample material from the sample surface.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Post-Closure Environmental Sampling and Inspection at the Amchitka Island, Alaska, Site - 17251

In the 1960's and early 1970's, three underground nuclear tests were conducted on Amchitka Island, Alaska. In 1965, the US Department of Defense-in conjunction with the US Atomic Energy Commission (AEC)-conducted the first of these nuclear tests, Long Shot, to provide data that would improve US capabilities for detecting underground nuclear explosions. In 1969, AEC conducted the second test, Milrow, to explore the feasibility of detonating a much larger device. In 1971, AEC conducted the third test, Cannikin, which was the largest underground test ever conducted by the US. The Long-Term Surveillance Plan (LTSP) for the Amchitka, Alaska, Site details how the US Department of Energy Office of Legacy Management (LM) intends to fulfill its mission to protect human health and the environment at and around the Amchitka Island site. The LTSP calls for monitoring to be performed every 5 years, at least during the initial phase of the project. The purpose of the monitoring is to develop a baseline of activity concentrations for selected radionuclides in biota, water, and soil, both on Amchitka Island and at the reference location on Adak Island, approximately 322 kilometers (200 miles) northeast of Amchitka. In addition to the environmental monitoring activities, seven mud pit caps that contain diesel-contaminated soils are inspected. The plan for biological and water sampling (both seawater and freshwater) during the May 2016 sampling event was developed through close coordination with the primary stakeholders, including the Alaska Department of Environmental Conservation, the Aleutian Pribilof Islands Association, and the US Fish and Wildlife Service. The environmental sampling in 2016 is a continuation of LM's evaluation of Amchitka Island's environment. Previous results from similar monitoring programs in 2004 and 2011 indicate that the environment is not being impacted by radionuclide migration and uptake from the underground nuclear testing conducted beneath Amchitka Island; consequently, subsistence and commercial-catch seafood is safe for human consumption. The collection of biota samples (rockfish, Irish lords, greenling, and rockweed) for cesium-134 ({sup 134}Cs), cesium-137 ({sup 137}Cs), plutonium-239 ({sup 239}Pu), plutonium-240 ({sup 240}Pu), and freshwater and seawater samples for {sup 134}Cs, {sup 137}Cs, and tritium ({sup 3}H) was the primary objective of the 2016 sampling effort. Rockfish, Irish lords, and greenling are resident, nonmigratory fish species that spend their entire life cycle in the marine environment, and rockweed is an inter-tidal species that may concentrate cesium. The seawater samples were collected primarily to determine if leakage from the Long Shot detonation could be detected and, secondarily, to compare with the background seawater samples collected from Adak Island. Cesium isotopes are also being analyzed to better understand the potential impact that the Fukushima-Daiichi release might have on the Amchitka and Adak environments. The target detection limits used for the 2016 sampling are lower than those used in previous studies. The lower detection limits make it possible for LM to delineate background activity levels for the radionuclides of interest. Data from the 2016 sampling event go beyond assessing food safety and focus on detecting leakage from the underground nuclear explosions. Additionally, the baseline activity concentrations obtained for the reference area (Adak Island) will enable identification of quantitative statistical trends in the results of future sampling programs. Sampling programs conducted in 2021 and beyond will have an objective to assess the statistical trends of radioactivity levels in the Amchitka Island environment. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Challenges to Collection of High Quality Samples of Saltstone - 17468

The Savannah River Site (SRS) Saltstone Disposal Facility (SDF) is used to dispose of low-level radioactive liquid waste in the form of grout. The SDF is comprised of a series of concrete saltstone disposal units (SDUs) that receive the grout. The grout solidifies into a cementitious waste form known as saltstone. Properties of saltstone that influence contaminant release have been measured on simulant material but not on samples of emplaced saltstone because samples of emplaced radioactive saltstone are difficult to obtain, transport, and store in a manner that protects the properties of interest. Savannah River Remediation (SRR) initiated a project to obtain samples of emplaced saltstone such that the two critical properties, hydraulic conductivity and reduction capacity, are negligibly impacted by the sample collection effort. The sample collection project was established to manage sample collection efforts beginning with sample collection mock-up activities through field execution. The project focused on three phases: mock-up in a clean environment, development of equipment needed to maintain an inert environment during sample transport and laboratory storage, and coordination of Facility operations and support resources and schedules to support sample collection. A mock-up facility was constructed at SRS to mimic the SDU. Core drill equipment was tested, procedures developed, and operator training conducted using the mockup facility. Concurrent with mock-up activities, inert transportation and storage equipment was designed, manufactured, tested, and specific operating instruction included in the sample collection procedure. Inerting equipment minimized oxidation from the atmosphere as the samples were removed from the disposal unit, transported, and stored in the laboratory awaiting analysis. Coordination with the Saltstone Facility began during construction of the mock-up platform to collect current as-built information for platform construction. Baseline data was collected from the disposal unit vapor space to assess the potential for personnel exposure from chemical hazards associated with trapped vapors. Based on this data, mitigating actions were incorporated into the project scope. Finally, project and facility schedules were integrated to assure that facility non-processing windows, support personnel, equipment fabrication, and field preparation activities were in alignment and supportive of the overall sample collection objectives. During May 2014, 485 linear cm of approximately 5 cm diameter radioactive core material was successfully collected from three access ports in SDU Cell 2A, inerted, transported to the laboratory, and stored in an inert environment for analysis. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Improved Nested Sampling and Surrogate-Enabled Comparison With Other Marginal Likelihood Estimators

Estimating marginal likelihood is of central importance to Bayesian model selection and/or model averaging. The nested sampling method has been recently used together with the Metropolis-Hasting (M-H) sampling algorithm for estimating marginal likelihood. This study develops a new implementation of nested sampling by using the DiffeRential Evolution Adaptive Metropolis (DREAMzs) sampling algorithm. The two implementations of nested sampling are evaluated for four models of a synthetic groundwater flow modeling. The DREAMzs-based nested sampling outperforms the M-H-based nested sampling in terms of their accuracy, convergence, efficiency, and stability, which is attributed to the fact that DREAMzs is more robust than M-H for parameter sampling. The nested sampling method is also compared with four other methods (arithmetic mean, harmonic mean, stabilized harmonic mean, and thermodynamic integration) commonly used for estimating marginal likelihood and posterior probability of the four groundwater models. The comparative study requires hundreds of millions of model executions, which would not be possible without using surrogate models to replace the original models. Using the arithmetic mean estimator as the reference, the comparison reveals that thermodynamic integration outperforms nested sampling in terms of accuracy and stability, whereas nested sampling is more computationally efficient to reach to convergence. Here, the harmonic mean and stabilized harmonic mean methods give the worst marginal likelihood estimation. Accurate marginal likelihood estimation is important for accurate estimation of posterior model probability and better predictive performance of Bayesian model averaging.

54 ENVIRONMENTAL SCIENCES↗