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DOE OSTI2012

Using Comparative Genomics for Inquiry-Based Learning to Dissect Virulence of Escherichia coli O157:H7 and Yersinia pestis

Genomics and bioinformatics are topics of increasing interest in undergraduate biological science curricula. Many existing exercises focus on gene annotation and analysis of a single genome. In this paper, we present two educational modules designed to enable students to learn and apply fundamental concepts in comparative genomics using examples related to bacterial pathogenesis. Students first examine alignments of genomes of Escherichia coli O157:H7 strains isolated from three food-poisoning outbreaks using the multiple-genome alignment tool Mauve. Students investigate conservation of virulence factors using the Mauve viewer and by browsing annotations available at the A Systematic Annotation Package for Community Analysis of Genomes database. In the second module, students use an alignment of five Yersinia pestis genomes to analyze single-nucleotide polymorphisms of three genes to classify strains into biovar groups. Students are then given sequences of bacterial DNA amplified from the teeth of corpses from the first and second pandemics of the bubonic plague and asked to classify these new samples. Learning-assessment results reveal student improvement in self-efficacy and content knowledge, as well as students' ability to use BLAST to identify genomic islands and conduct analyses of virulence factors from E. coli O157:H7 or Y. pestis. Each of these educational modules offers educators new ready-to-implement resources for integrating comparative genomic topics into their curricula.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2022

January 2022 Operational Highlights

The Indexing Lab is now complete and includes classified and unclassified computers, safes and work stations. Staff capture metadata and catalog materials, including classified reports, directors’ correspondence and Rocky Flats materials to ensure the holdings are discoverable and retrievable. Access protocols were updated for products related to the LANL Annual Assessment in the Online Vault (OLV) classified repository. The Annual Assessment is a yearly analysis of the weapons systems in the nation’s nuclear stockpile. The Standardization Quality Assessment (SQA) for the Online Vault (OLV) classified repository was completed and contained no findings. Beta testing, or customer validation, began for the metrics database that generates metrics reports and visualizations from NSRC customer projects.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS2002

Calibration and Data Retrieval Algorithms for the NASA Langley/Ames Diode Laser Hygrometer for the NASA Trace-P Mission

This paper describes the procedures and algorithms for the laboratory calibration and the field data retrieval of the NASA Langley / Ames Diode Laser Hygrometer as implemented during the NASA Trace-P mission during February to April 2000. The calibration is based on a NIST traceable dewpoint hygrometer using relatively high humidity and short pathlength. Two water lines of widely different strengths are used to increase the dynamic range of the instrument in the course of a flight. The laboratory results are incorporated into a numerical model of the second harmonic spectrum for each of the two spectral window regions using spectroscopic parameters from the HITRAN database and other sources, allowing water vapor retrieval at upper tropospheric and lower stratospheric temperatures and humidity levels. The data retrieval algorithm is simple, numerically stable, and accurate. A comparison with other water vapor instruments on board the NASA DC-8 and ER-2 aircraft is presented.

Podolske, James R.↗

NASA NTRS2012

NASA Thesaurus Data File

The NASA Thesaurus contains the authorized NASA subject terms used to index and retrieve materials in the NASA Aeronautics and Space Database (NA&SD) and NASA Technical Reports Server (NTRS). The scope of this controlled vocabulary includes not only aerospace engineering, but all supporting areas of engineering and physics, the natural space sciences (astronomy, astrophysics, planetary science), Earth sciences, and the biological sciences. The NASA Thesaurus Data File contains all valid terms and hierarchical relationships, USE references, and related terms in machine-readable form. The Data File is available in the following formats: RDF/SKOS, RDF/OWL, ZThes-1.0, and CSV/TXT.

Source record↗

DOE OSTI2018

Coupled Approximation of U.S. Driving Speed and Volume Statistics Using Spatial Conflation and Temporal Disaggregation

The advent of mobile devices with embedded global positioning systems has allowed commercial providers of real-time traffic data to develop highly accurate estimates of network-level vehicle speeds. Traffic speed data have far outpaced the availability and accuracy of real-time traffic volume information. Limited to a relatively small number of permanent and temporary traffic counters in any city, traffic volumes typically only cover a handful of roadways with inconsistent temporal resolution. This work addressed this data gap by coupling a commercial dataset of typical traffic speeds (by roadway and time of week) from TomTom to the U.S. FHWA's Highway Performance Monitoring System database of annual average daily traffic (AADT) counts by roadway. This work is technically novel in its solution for establishing a national crosswalk between independent network geometries using spatial conflation and big data techniques. The resulting product is a national dataset providing traffic speed and volume estimates under typical conditions for all U.S. roadways with AADT values.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2016

The Alaska Arctic Vegetation Archive (AVA-AK)

The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation data with 25-m or better precision. Species cover data and header data are stored in a Turboveg database. A standardized Pan Arctic Species List provides a consistent nomenclature for vascular plants, bryophytes, and lichens in the archive. A web-based online Alaska Arctic Geoecological Atlas (AGA-AK) allows viewing and downloading the species data in a variety of formats, and provides access to a wide variety of ancillary data. We conducted a preliminary cluster analysis of the first 16 datasets (1,613 plots) to examine how the spectrum of derived clusters is related to the suite of datasets, habitat types, and environmental gradients. Here, we present the contents of the archive, assess its strengths and weaknesses, and provide three supplementary files that include the data dictionary, a list of habitat types, an overview of the datasets, and details of the cluster analysis.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2012

Code Qualification of Structural Materials for AFCI Advanced Recycling Reactors

This report summarizes the further findings from the assessments of current status and future needs in code qualification and licensing of reference structural materials and new advanced alloys for advanced recycling reactors (ARRs) in support of Advanced Fuel Cycle Initiative (AFCI). The work is a combined effort between Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL) with ANL as the technical lead, as part of Advanced Structural Materials Program for AFCI Reactor Campaign. The report is the second deliverable in FY08 (M505011401) under the work package 'Advanced Materials Code Qualification'. The overall objective of the Advanced Materials Code Qualification project is to evaluate key requirements for the ASME Code qualification and the Nuclear Regulatory Commission (NRC) approval of structural materials in support of the design and licensing of the ARR. Advanced materials are a critical element in the development of sodium reactor technologies. Enhanced materials performance not only improves safety margins and provides design flexibility, but also is essential for the economics of future advanced sodium reactors. Code qualification and licensing of advanced materials are prominent needs for developing and implementing advanced sodium reactor technologies. Nuclear structural component design in the U.S. must comply with the ASME Boiler and Pressure Vessel Code Section III (Rules for Construction of Nuclear Facility Components) and the NRC grants the operational license. As the ARR will operate at higher temperatures than the current light water reactors (LWRs), the design of elevated-temperature components must comply with ASME Subsection NH (Class 1 Components in Elevated Temperature Service). However, the NRC has not approved the use of Subsection NH for reactor components, and this puts additional burdens on materials qualification of the ARR. In the past licensing review for the Clinch River Breeder Reactor Project (CRBRP) and the Power Reactor Innovative Small Module (PRISM), the NRC/Advisory Committee on Reactor Safeguards (ACRS) raised numerous safety-related issues regarding elevated-temperature structural integrity criteria. Most of these issues remained unresolved today. These critical licensing reviews provide a basis for the evaluation of underlying technical issues for future advanced sodium-cooled reactors. Major materials performance issues and high temperature design methodology issues pertinent to the ARR are addressed in the report. The report is organized as follows: the ARR reference design concepts proposed by the Argonne National Laboratory and four industrial consortia were reviewed first, followed by a summary of the major code qualification and licensing issues for the ARR structural materials. The available database is presented for the ASME Code-qualified structural alloys (e.g. 304, 316 stainless steels, 2.25Cr-1Mo, and mod.9Cr-1Mo), including physical properties, tensile properties, impact properties and fracture toughness, creep, fatigue, creep-fatigue interaction, microstructural stability during long-term thermal aging, material degradation in sodium environments and effects of neutron irradiation for both base metals and weld metals. An assessment of modified versions of Type 316 SS, i.e. Type 316LN and its Japanese version, 316FR, was conducted to provide a perspective for codification of 316LN or 316FR in Subsection NH. Current status and data availability of four new advanced alloys, i.e. NF616, NF616+TMT, NF709, and HT-UPS, are also addressed to identify the R&D needs for their code qualification for ARR applications. For both conventional and new alloys, issues related to high temperature design methodology are described to address the needs for improvements for the ARR design and licensing. Assessments have shown that there are significant data gaps for the full qualification and licensing of the ARR structural materials. Development and evaluation of structural materials require a variety of experimental facilities that have been seriously degraded in the past. The availability and additional needs for the key experimental facilities are summarized at the end of the report. Detailed information covered in each Chapter is given.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2015

Validation of the National Solar Radiation Database (NSRDB) (2005-2012): Preprint

Publicly accessible, high-quality, long-term, satellite-based solar resource data is foundational and critical to solar technologies to quantify system output predictions and deploy solar energy technologies in grid-tied systems. Solar radiation models have been in development for more than three decades. For many years, the National Renewable Energy Laboratory (NREL) developed and/or updated such models through the National Solar Radiation Data Base (NSRDB). There are two widely used approaches to derive solar resource data from models: (a) an empirical approach that relates ground-based observations to satellite measurements and (b) a physics-based approach that considers the radiation received at the satellite and creates retrievals to estimate clouds and surface radiation. Although empirical methods have been traditionally used for computing surface radiation, the advent of faster computing has made operational physical models viable. The Global Solar Insolation Project (GSIP) is an operational physical model from the National Oceanic and Atmospheric Administration (NOAA) that computes global horizontal irradiance (GHI) using the visible and infrared channel measurements from the Geostationary Operational Environmental Satellites (GOES) system. GSIP uses a two-stage scheme that first retrieves cloud properties and then uses those properties in the Satellite Algorithm for Surface Radiation Budget (SASRAB) model to calculate surface radiation. NREL, the University of Wisconsin, and NOAA have recently collaborated to adapt GSIP to create a high temporal and spatial resolution data set. The product initially generates the cloud properties using the AVHRR Pathfinder Atmospheres-Extended (PATMOS-x) algorithms [3], whereas the GHI is calculated using SASRAB. Then NREL implements accurate and high-resolution input parameters such as aerosol optical depth (AOD) and precipitable water vapor (PWV) to compute direct normal irradiance (DNI) using the DISC model. The AOD and PWV, temperature, and pressure data are also combined with the MMAC model to simulate solar radiation under clear-sky conditions. The current NSRDB update is based on a 4-km x 4-km resolution at a 30-minute time interval, which has a higher temporal and spatial resolution. This paper demonstrates the evaluation of the data set using ground-measured data and detailed evaluation statistics. The result of the comparison shows a good correlation to the NSRDB data set. Further, an outline of the new version of the NSRDB and future plans for enhancement and improvement are provided.

14 SOLAR ENERGY↗

DOE OSTI2022

Harnessing structural stochasticity in the computational discovery and design of microstructures

This paper presents a deep generative model-based design methodology for tailoring the structural stochasticity of microstructures. Although numerous methods have been established for designing deterministic (periodic) or stochastic microstructures, a systematic design approach that allows the unified treatment of both deterministic and stochastic microstructure design domains has yet to be created. The proposed methodology resolves this issue by learning a unified feature space that embodies diverse structural patterns with continuously varying stochasticity levels. A highly diverse microstructure database is established to incorporate various types of deterministic and stochastic microstructure patterns. A property-aware deep generative model is proposed to learn a unified feature space of the structural characteristics, as well as the relationship between structure features and properties of interest. Autoencoder (AE), Variational Autoencoder (VAE), and Adversarial Autoencoder (AAE) are compared to understand their relative merits in the property-aware learning of the unified feature space. Microstructural designs with tailorable stochasticity and properties are obtained by searching the unified feature space. Multiple design cases are presented to demonstrate the capability of designing microstructures for structural stochasticity and properties. Furthermore, the proposed method is employed to create stochastically graded structures, which manipulate the mechanical behaviors by varying the local stochasticity of the structure.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Thermodynamic assessment of lithium halide reciprocal salt systems for energy applications

Lithium halides are of interest because of their unique applications as fuel or coolants in molten salt reactors (MSRs) and electrolytes in thermally activated batteries. Because iodine is an important fission product for MSRs, the Molten Salt Thermal Properties Database-Thermochemical (MSTDB-TC) is being expanded to include relevant iodide reciprocal salt systems. In this work, we assess the thermochemical properties of lithium halide pseudobinary systems based on reported experimental phase diagrams, eutectic temperatures, and enthalpies of mixing. Within the framework of the modified quasi-chemical model in the quadruplet approximation (MQMQA), extrapolations to the related pseudoternary and pseudoquaternary systems have been performed. The pseudoquaternary representations of phase equilibria, enthalpy, entropy, and heat capacity are represented in the resultant models. Of interest for generating source terms for accident analysis is the ability to compute the vapor pressures of the dominant iodide species for the systems at any composition. Here, an example of such calculations is provided for the LiF-LiI system at x LiI = 0.01 and x LiI = 0.70, in this case indicating that the LiI vapor species are predominant.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2014

The EB factory project. I. A fast, neural-net-based, general purpose light curve classifier optimized for eclipsing binaries

We describe a new neural-net-based light curve classifier and provide it with documentation as a ready-to-use tool for the community. While optimized for identification and classification of eclipsing binary stars, the classifier is general purpose, and has been developed for speed in the context of upcoming massive surveys such as the Large Synoptic Survey Telescope. A challenge for classifiers in the context of neural-net training and massive data sets is to minimize the number of parameters required to describe each light curve. We show that a simple and fast geometric representation that encodes the overall light curve shape, together with a chi-square parameter to capture higher-order morphology information results in efficient yet robust light curve classification, especially for eclipsing binaries. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for eclipsing binaries. We achieve similarly high retrieval rates for most other periodic variable-star classes, including RR Lyrae, Mira, and delta Scuti. However, the classifier currently has difficulty discriminating between different sub-classes of eclipsing binaries, and suffers a relatively low (∼60%) retrieval rate for multi-mode delta Cepheid stars. We find that it is imperative to train the classifier's neural network with exemplars that include the full range of light curve quality to which the classifier will be expected to perform; the classifier performs well on noisy light curves only when trained with noisy exemplars. The classifier source code, ancillary programs, a trained neural net, and a guide for use, are provided.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2016

THE METALLICITY EVOLUTION OF BLUE COMPACT DWARF GALAXIES FROM THE INTERMEDIATE REDSHIFT TO THE LOCAL UNIVERSE

We present oxygen abundance measurements for 74 blue compact dwarf (BCD) galaxies in the redshift range of [0.2, 0.5] using the strong-line method. The spectra of these objects are taken using Hectospec on the Multiple Mirror Telescope. More than half of these BCDs had dust attenuation corrected using the Balmer decrement method. For comparison, we also selected a sample of 2023 local BCDs from the Sloan Digital Sky Survey (SDSS) database. Based on the local and intermediate-z BCD samples, we investigated the cosmic evolution of the metallicity, star formation rate (SFR), and D{sub n}(4000) index. Compared with local BCDs, the intermediate-z BCDs had a systematically higher R23 ratio but a similar O32 ratio. Interestingly, no significant deviation in the mass–metallicity (MZ) relation was found between the intermediate-z and local BCDs. Besides the metallicity, the intermediate-z BCDs also exhibited an SFR distribution that was consistent with local BCDs, suggesting a weak dependence on redshift. The intermediate-z BCDs seemed to be younger than the local BCDs with lower D{sub n}(4000) index values. The insignificant deviation in the mass–metallicity and mass–SFR relations between intermediate-z and local BCDs indicates that the relations between the global parameters of low-mass compact galaxies may be universal. These results from low-mass compact galaxies could be used to place important observational constraints on galaxy formation and evolution models.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1992

Meteoroid, and debris special investigation group preliminary results: Size-frequency distribution and spatial density of large impact features on LDEF

All craters greater than or equal to 500 microns and penetration holes greater than or equal to 300 microns in diameter on the entire Long Duration Exposure Facility (LDEF) were documented. Summarized here are the observations on the LDEF frame, which exposed aluminum 6061-T6 in 26 specific directions relative to LDEF's velocity vector. In addition, the opportunity arose to characterize the penetration holes in the A0178 thermal blankets, which pointed in nine directions. For each of the 26 directions, LDEF provided time-area products that approach those afforded by all previous space-retrieved materials combined. The objective here is to provide a factual database pertaining to the largest collisional events on the entire LDEF spacecraft with a minimum of interpretation. This database may serve to encourage and guide more interpretative efforts and modeling attempts.

See, Thomas H.↗

NASA NTRS1999

Engineering Overview of a Multidisciplinary HSCT Design Framework Using Medium-Fidelity Analysis Codes

An objective of the HPCC Program at NASA Langley has been to promote the use of advanced computing techniques to more rapidly solve the problem of multidisciplinary optimization of a supersonic transport configuration. As a result, a software system has been designed and is being implemented to integrate a set of existing discipline analysis codes, some of them CPU-intensive, into a distributed computational framework for the design of a High Speed Civil Transport (HSCT) configuration. The proposed paper will describe the engineering aspects of integrating these analysis codes and additional interface codes into an automated design system. The objective of the design problem is to optimize the aircraft weight for given mission conditions, range, and payload requirements, subject to aerodynamic, structural, and performance constraints. The design variables include both thicknesses of structural elements and geometric parameters that define the external aircraft shape. An optimization model has been adopted that uses the multidisciplinary analysis results and the derivatives of the solution with respect to the design variables to formulate a linearized model that provides input to the CONMIN optimization code, which outputs new values for the design variables. The analysis process begins by deriving the updated geometries and grids from the baseline geometries and grids using the new values for the design variables. This free-form deformation approach provides internal FEM (finite element method) grids that are consistent with aerodynamic surface grids. The next step involves using the derived FEM and section properties in a weights process to calculate detailed weights and the center of gravity location for specified flight conditions. The weights process computes the as-built weight, weight distribution, and weight sensitivities for given aircraft configurations at various mass cases. Currently, two mass cases are considered: cruise and gross take-off weight (GTOW). Weights information is obtained from correlations of data from three sources: 1) as-built initial structural and non-structural weights from an existing database, 2) theoretical FEM structural weights and sensitivities from Genesis, and 3) empirical as-built weight increments, non-structural weights, and weight sensitivities from FLOPS. For the aeroelastic analysis, a variable-fidelity aerodynamic analysis has been adopted. This approach uses infrequent CPU-intensive non-linear CFD to calculate a non-linear correction relative to a linear aero calculation for the same aerodynamic surface at an angle of attack that results in the same configuration lift. For efficiency, this nonlinear correction is applied after each subsequent linear aero solution during the iterations between the aerodynamic and structural analyses. Convergence is achieved when the vehicle shape being used for the aerodynamic calculations is consistent with the structural deformations caused by the aerodynamic loads. To make the structural analyses more efficient, a linearized structural deformation model has been adopted, in which a single stiffness matrix can be used to solve for the deformations under all the load conditions. Using the converged aerodynamic loads, a final set of structural analyses are performed to determine the stress distributions and the buckling conditions for constraint calculation. Performance constraints are obtained by running FLOPS using drag polars that are computed using results from non-linear corrections to the linear aero code plus several codes to provide drag increments due to skin friction, wave drag, and other miscellaneous drag contributions. The status of the integration effort will be presented in the proposed paper, and results will be provided that illustrate the degree of accuracy in the linearizations that have been employed.

Weston, R. P.↗

NASA NTRS2003

Electron Probe MicroAnalysis (EPMA) Standards. Issues Related to Measurement and Accuracy Evaluation in EPMA

Electron-probe microanalysis standards and issues related to measurement and accuracy of microanalysis will be discussed. Critical evaluation of standards based on homogeneity and comparison with wet-chemical analysis will be made. Measurement problems such as spectrometer dead-time will be discussed. Analytical accuracy issues will be evaluated for systems by alpha-factor analysis and comparison with experimental k-ratio databases.

Carpenter, Paul↗

DOE OSTI2015

Implementation of Remaining Useful Lifetime Transformer Models in the Fleet-Wide Prognostic and Health Management Suite

Research and development efforts are required to address aging and reliability concerns of the existing fleet of nuclear power plants. As most plants continue to operate beyond the license life (i.e., towards 60 or 80 years), plant components are more likely to incur age-related degradation mechanisms. To assess and manage the health of aging plant assets across the nuclear industry, the Electric Power Research Institute has developed a web-based Fleet-Wide Prognostic and Health Management (FW-PHM) Suite for diagnosis and prognosis. FW-PHM is a set of web-based diagnostic and prognostic tools and databases, comprised of the Diagnostic Advisor, the Asset Fault Signature Database, the Remaining Useful Life Advisor, and the Remaining Useful Life Database, that serves as an integrated health monitoring architecture. The main focus of this paper is the implementation of prognostic models for generator step-up transformers in the FW-PHM Suite. One prognostic model discussed is based on the functional relationship between degree of polymerization, (the most commonly used metrics to assess the health of the winding insulation in a transformer) and furfural concentration in the insulating oil. The other model is based on thermal-induced degradation of the transformer insulation. By utilizing transformer loading information, established thermal models are used to estimate the hot spot temperature inside the transformer winding. Both models are implemented in the Remaining Useful Life Database of the FW-PHM Suite. The Remaining Useful Life Advisor utilizes the implemented prognostic models to estimate the remaining useful life of the paper winding insulation in the transformer based on actual oil testing and operational data.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

NASA NTRS2007

Stable Low Cloud Phase II: Nocturnal Event Study

This report describes the work done by the Applied Meteorology Unit (AMU) in developing a database of nights that experienced rapid (< 90 minutes) low cloud formation in a stable atmosphere, resulting in ceilings at the Shuttle Landing Facility (TTS) that violated Space Shuttle Flight Rules (FR). This work is the second phase of a similar AMU task that examined the same phenomena during the day. In the first phase of this work, the meteorological conditions favoring the rapid formation of low ceilings include the presence of any inversion below 8000 ft, high relative humidity (RH) beneath the inversion and a clockwise turning of the winds from the surface to the middle troposphere (-15000 ft). The AMU compared and contrasted the atmospheric and thermodynamic conditions between nights with rapid low ceiling formation and nights with low ceilings resulting from other mechanisms. The AMU found that there was little to discern between the rapidly-forming ceiling nights and other low ceiling nights at TTS. When a rapid development occurred, the average RH below the inversions was 87% while non-events had an average RH of 79%. One key parameter appeared to be the vertical wind profile in the Cape Canaveral, FL radiosonde (XMR) sounding. Eighty-three percent of the rapid development events had veering winds with height from the surface to the middle troposphere (-15,000 ft) while 61% of the non-events had veering winds with height. Veering winds indicate a warm-advection regime, which supports large-scale rising motion and ultimately cloud formation in a moist environment. However, only six of the nights (out of 86 events examined) with low cloud ceilings had an occurrence of rapidly developing ceilings. Since only 7% rapid development events were observed in this dataset, it is likely that rapid low cloud development is not a common occurrence during the night, or at least not as common as during the day. In the AMU work on the daytime rapid low cloud development (Case and Wheeler 2005), nearly 30% of the low cloud ceiling cases investigated were identified as rapidly developing events. Forecasters at the Space Meteorology Group (SMG) issue 30 to 90 minute forecasts for low cloud ceilings at TTS to support Space Shuttle landings. Mission verification statistics have shown ceilings to be the number one forecast challenge. More specifically, forecasters at SMG are concerned with any rapidly developing clouds/ceilings below 8000 R in a stable, capped thermodynamic environment. Therefore, the AMU was tasked to examine archived events of rapid stable cloud formation resulting in ceilings below 8000 ft, and document the atmospheric regimes favoring this type of cloud development. The AMU examined the cool season months of November to March during the years of 1994-2005 for nights that had low-level inversions and rapid, stable low cloud formation that resulted in ceilings violating the Space Shuttle FR. The AMU wrote and modified existing code to identify inversions from the evening and morning XMR radiosonde during the cool season and output pertinent sounding information. They parsed all days with cloud ceilings below 8000 ft at TTS, forming a database of possible rapidly-developing low ceiling events. Nights with precipitation or noticeable fog burn-off situations were excluded from the database. Only the nighttime hours were examined for possible ceiling development events since the daytime events were examined in the first phase of this work. The report presents one sample case of rapidly-developing low cloud ceilings. The case depicts the representative meteorological and thermodynamic characteristics of such events. The case also illustrates how quickly the cloud decks can develop, sometimes forming in 30 minutes or less. The report also summarizes the composite meteorological conditions for 6 event nights with rapid low cloud ceiling formation and 80 non-events nights consisting of advection or widespread low cloud ceilings. The teorological conditions were quite similar for both the event and non-event nights, since both types of nights experienced low cloud ceilings. Both types of nights had a relatively moist environment beneath an inversion based below 8000 ft.

Bauman, William H., III↗

DOE OSTI2016

Hydrothermal Liquefaction and Upgrading of Municipal Wastewater Treatment Plant Sludge: A Preliminary Techno-Economic Analysis, Rev.1

A preliminary process model and techno-economic analysis (TEA) was completed for fuel produced from hydrothermal liquefaction (HTL) of sludge waste from a municipal wastewater treatment plant (WWTP) and subsequent biocrude upgrading. The model is adapted from previous work by Jones et al. (2014) for algae HTL, using experimental data generated in fiscal year 2015 (FY15) bench-scale HTL testing of sludge waste streams. Testing was performed on sludge samples received from Metro Vancouver’s Annacis Island WWTP (Vancouver, B.C.) as part of a collaborative project with the Water Environment and Reuse Foundation (WERF). The full set of sludge HTL testing data from this effort will be documented in a separate report to be issued by WERF. This analysis is based on limited testing data and therefore should be considered preliminary. In addition, the testing was conducted with the goal of successful operation, and therefore does not represent an optimized process. Future refinements are necessary to improve the robustness of the model, including a cross-check of modeled biocrude components with the experimental GCMS data and investigation of equipment costs most appropriate at the relatively small scales used here. Environmental sustainability metrics analysis is also needed to understand the broader impact of this technology pathway. The base case scenario for the analysis consists of 10 HTL plants, each processing 100 dry U.S. ton/day (92.4 ton/day on a dry, ash-free basis) of sludge waste and producing 234 barrel per stream day (BPSD) biocrude, feeding into a centralized biocrude upgrading facility that produces 2,020 barrel per standard day of final fuel. This scale was chosen based upon initial wastewater treatment plant data collected by PNNL’s resource assessment team from the EPA’s Clean Watersheds Needs Survey database (EPA 2015a) and a rough estimate of what the potential sludge availability might be within a 100-mile radius. In addition, we received valuable feedback from the wastewater treatment industry as part of the WERF collaboration that helped form the basis for the selected HTL and upgrading plant scales and feedstock credit (current cost of disposal). It is assumed that the sludge is currently disposed of at $16.20/wet ton ($46/dry ton at 35% solids; $50/ton dry, ash-free basis) and this is included as a feedstock credit in the operating costs. The base case assumptions result in a minimum biocrude selling price of $3.8/gge and a minimum final upgraded fuel selling price of $4.9/gge. Several areas of process improvement and refinements to the analysis have the potential to significantly improve economics relative to the base case: •Optimization of HTL sludge feed solids content •Optimization of HTL biocrude yield •Optimization of HTL reactor liquid hourly space velocity (LHSV) •Optimization of fuel yield from hydrotreating •Combined large and small HTL scales specific to regions (e.g., metropolitan and suburban plants) Combined improvements believed to be achievable in these areas can potentially reduce the minimum selling price of biocrude and final upgraded fuel by about 50%. Further improvements may be possible through recovery of higher value components from the HTL aqueous phase, as being investigated under separate PNNL projects. Upgrading the biocrude at an existing petroleum refinery could also reduce the MFSP, although this option requires further testing to ensure compatibility and mitigation of risks to a refinery. And finally, recycling the HTL aqueous phase product stream back to the headworks of the WWTP (with no catalytic hydrothermal gasification treatment) can significantly reduce cost. This option is uniquely appropriate for application at a water treatment facility but also requires further investigation to determine any technical and economic challenges related to the extra chemical oxygen demand (COD) associated with the recycled water.

09 BIOMASS FUELS↗