Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “content”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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

At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Aureochromes maintain polyunsaturated fatty acid content in Nannochloropsis oceanica

Abstract Nannochloropsis oceanica, like other stramenopile microalgae, is rich in long-chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA). We observed that fatty acid desaturases (FADs) involved in LC-PUFA biosynthesis were among the strongest blue light-induced genes in N. oceanica CCMP1779. Blue light was also necessary for maintaining LC-PUFA levels in CCMP1779 cells, and growth under red light led to a reduction in EPA content. Aureochromes are stramenopile-specific proteins that contain a light–oxygen–voltage (LOV)-sensing domain that associates with a flavin mononucleotide and is able to sense blue light. These proteins also contain a basic leucine zipper DNA-binding motif and can act as blue light-regulated transcription factors by associating with an E-box like motif, which we found enriched in the promoters of blue light-induced genes. We demonstrated that, in vitro, two CCMP1779 aureochromes were able to absorb blue light. Moreover, the loss or reduction of the expression of any of the three aureochrome genes led to a decrease in the blue light-specific induction of several FADs in CCMP1779. EPA content was also significantly reduced in NoAUREO2 and NoAUREO4 mutants. Taken together, our results indicate that aureochromes mediate blue light-dependent regulation of LC-PUFA content in N. oceanica CCMP1779 cells.

Plant Sciences↗
DOE OSTI2022

Universal relation between doping content and normal-state resistance in gate voltage tuned ultrathin Bi 2 Sr 2 CaCu 2 O 8 + x flakes

We report gate voltage tunable ultra-thin high-T c cuprates supply a unique platform to investigate the electronic phase diagram and superconductor-insulator transition. One of the challenges in this field is the precise determination of the doping content in the underdoped non-superconducting region. Here we report the discovery of a universal relation between the doping content p and the normal-state resistance at a fixed temperature R(T f ), p = α + β ln[1/R(T f )], in the ultra-thin Bi 2 Sr 2 CaCu 2 O 8+x flakes. The in-depth analysis shows that the evolution of carrier scattering probability with doping content and the change of effective mass caused by superconductor-insulator transition are two key factors leading to this logarithmic relation. Based on our finding, the more precise electronic phase diagram can be established. In addition, the superconductor-insulator transition is verified to be a quantum phase transition using a finite size scaling analysis. The scaling exponent z v is found to have a close correlation with the disorder levels. The present result provides an important foundation to investigate the fascinating electronic states in the ultra-thin cuprates.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Effects of Grain Size and Interstitial Content on Recrystallization in Nb after Cold Rolling

A fully recrystallized microstructure with a fine grain size can improve the performance of superconducting radio-frequency (SRF) cavities produced from high-purity Nb (ASTM B393–18 Type 5 Nb) while providing mechanical strength. Recrystallization depends on impurity content, initial microstructure, deformation state, and annealing conditions. To better understand how fine-grained, fully recrystallized microstructures may be produced, the recrystallization behaviors of Type 5 and Type 2 Nb materials were studied. Type 5 Nb specimens were produced with both fine and coarse initial grain sizes. All were cold rolled and then annealed under vacuum for one hour to determine the rolling reductions and temperatures required for recrystallization. The recrystallized fraction exceeded 95% in fine-grained Type 5 Nb rolled to a 30% or greater thickness reduction and then annealed at 800 °C or higher. The coarse grained Type 5 Nb required greater rolling reductions to produce any recrystallized grains at 800 °C. The higher interstitial content of the Type 2 Nb required a temperature of 1000 °C or higher to reach a recrystallized fraction greater than 95% in specimens rolled to a 60% reduction. Recrystallization is more easily achieved during annealing at a given temperature for a set time by increasing rolling reduction, decreasing interstitial content, and decreasing initial grain size prior to cold rolling. In conclusion, to avoid grain growth following recrystallization, which increases grain size, the minimum time and temperature necessary for complete recrystallization should be applied.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2012

Effects of the iron content and redox state on the structure of sodium borosilicate glasses: A Raman, Moessbauer and boron K-edge XANES spectroscopy study

The structure of iron-bearing sodium borosilicate glasses with up to 10 mol% FeO has been investigated in the range 0.15 ≤ Fe{sup 3+}/SFe ≤ 0.95. According to Moessbauer spectroscopy, Fe{sup 3+} and Fe{sup 2+} are mainly in tetrahedral and octahedral coordination, respectively, although other coordination states exist for both cations. From XANES experiments, we conclude that increasing Fe content and varying redox states have only a minor effect on the relative proportions of BO{sub 3} and BO{sub 4} units. In Raman spectra, a decrease of the proportion of BO{sub 4} species present in danburite-like units (Na{sub 2}O.B{sub 2}O{sub 3}.2SiO{sub 2}) is found upon increasing iron content and oxidizing state. Whereas the insensitivity of the overall boron speciation to iron content and redox state points to weak interactions between boron and iron, the changes affecting BO{sub 4} species do indicate a more subtle interplay between Fe{sup 3+} and the other tetrahedrally coordinated cations (Si,B) because of the competition between tetrahedral Fe{sup 3+} and B{sup 3+} for charge compensation by Na{sup +}. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

WE-AB-BRA-01: 3D-2D Image Registration for Target Localization in Spine Surgery: Comparison of Similarity Metrics Against Robustness to Content Mismatch

Purpose: In image-guided spine surgery, mapping 3D preoperative images to 2D intraoperative images via 3D-2D registration can provide valuable assistance in target localization. However, the presence of surgical instrumentation, hardware implants, and soft-tissue resection/displacement causes mismatches in image content, confounding existing registration methods. Manual/semi-automatic methods to mask such extraneous content is time consuming, user-dependent, error prone, and disruptive to clinical workflow. We developed and evaluated 2 novel similarity metrics within a robust registration framework to overcome such challenges in target localization. Methods: An IRB-approved retrospective study in 19 spine surgery patients included 19 preoperative 3D CT images and 50 intraoperative mobile radiographs in cervical, thoracic, and lumbar spine regions. A neuroradiologist provided truth definition of vertebral positions in CT and radiography. 3D-2D registration was performed using the CMA-ES optimizer with 4 gradient-based image similarity metrics: (1) gradient information (GI); (2) gradient correlation (GC); (3) a novel variant referred to as gradient orientation (GO); and (4) a second variant referred to as truncated gradient correlation (TGC). Registration accuracy was evaluated in terms of the projection distance error (PDE) of the vertebral levels. Results: Conventional similarity metrics were susceptible to gross registration error and failure modes associated with the presence of surgical instrumentation: for GI, the median PDE and interquartile range was 33.0±43.6 mm; similarly for GC, PDE = 23.0±92.6 mm respectively. The robust metrics GO and TGC, on the other hand, demonstrated major improvement in PDE (7.6 ±9.4 mm and 8.1± 18.1 mm, respectively) and elimination of gross failure modes. Conclusion: The proposed GO and TGC similarity measures improve registration accuracy and robustness to gross failure in the presence of strong image content mismatch. Such registration capability could offer valuable assistance in target localization without disruption of clinical workflow. G. Kleinszig and S. Vogt are employees of Siemens Healthcare.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Predicting variable gene content in Escherichia coli using conserved genes

Having the ability to predict the protein-encoding gene content of an incomplete genome or metagenome-assembled genome is important for a variety of bioinformatic tasks. In this study, as a proof of concept, we built machine learning classifiers for predicting variable gene content in Escherichia coli genomes using only the nucleotide k-mers from a set of 100 conserved genes as features. Protein families were used to define orthologs, and a single classifier was built for predicting the presence or absence of each protein family occurring in 10%–90% of all E. coli genomes. The resulting set of 3,259 extreme gradient boosting classifiers had a per-genome average macro F1 score of 0.944 [0.943–0.945, 95% CI]. We show that the F1 scores are stable across multi-locus sequence types and that the trend can be recapitulated by sampling a smaller number of core genes or diverse input genomes. Surprisingly, the presence or absence of poorly annotated proteins, including “hypothetical proteins” was accurately predicted (F1 = 0.902 [0.898–0.906, 95% CI]). Models for proteins with horizontal gene transfer-related functions had slightly lower F1 scores but were still accurate (F1s = 0.895, 0.872, 0.824, and 0.841 for transposon, phage, plasmid, and antimicrobial resistance-related functions, respectively). Finally, using a holdout set of 419 diverse E. coli genomes that were isolated from freshwater environmental sources, we observed an average per-genome F1 score of 0.880 [0.876–0.883, 95% CI], demonstrating the extensibility of the models. Overall, this study provides a framework for predicting variable gene content using a limited amount of input sequence data.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Gas Content and Structure of Coal in Donets Basin

The integrated study of coal is performed using methods of optical and electron paramagnetic resonances, infrared spectroscopy and Raman spectroscopy. It is found that gas content of coal is governed by the rank of coal and its material constitution as well as by the coal bed structure at the macro-, micro- and nano-levels which interwork. It is discovered that the size and amount of bubbles, of paleo-origin presumably, and the content of coalbed methane are related. The influence of each scale level of the coal bed structure on the gas content is revealed. The authors illustrate benefits of the integrated study of gasbearing coal with the physical methods that complement one the other at different levels of coal structure.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Valence-band offsets in strained SiGeSn/Si layers with different tin contents

Admittance spectroscopy is used to study hole states in Si{sub 0.7–y}Ge{sub 0.3}Sn{sub y}/Si quantum wells in the tin content range y = 0.04–0.1. It is found that the hole binding energy increases with tin content. The hole size-quantization energies in structures containing a pseudomorphic Si{sub 0.7–y}Ge{sub 0.3}Sn{sub y} layer in the Si matrix are determined using the 6-band kp method. The valence-band offset at the Si{sub 0.7–y}Ge{sub 0.3}Sn{sub y} heterointerface is determined by combining the numerical calculation results and experimental data. It is found that the dependence of the experimental values of the valence-band offsets between pseudomorphic Si{sub 0.7–y}Ge{sub 0.3}Sn{sub y} layers and Si on the tin content is described by the expression ΔE{sub V}{sup exp} = (0.21 ± 0.01) + (3.35 ± 7.8 × 10{sup –4})y eV.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Effect of the Oxygen Content on the Local Environment of Fe Atoms in Anion-Deficient SrFeO{sub 3 – δ}

The specific features of the structure in a polycrystalline anion-deficient strontium ferrite SrFeO{sub 3 – δ} have been studied at different oxygen contents by the Mössbauer spectroscopy, X-ray diffraction, and scanning electron microscopy. Three compounds with different compositions have been prepared in the dependence on the condition of heat treatment. Within each of the structures, there are several nonequivalent positions of Fe corresponding to different valence states of Fe and different local oxygen environments, the relation and the degree of distortion of which are changed in the dependence on the oxygen content. Based on the Mössbauer data, the oxygen content in each of the structures is estimated. Yet another ideal Sr{sub 16}Fe{sub 16}O{sub 45} composition of the SrFeO{sub 3 – δ} compound is proposed for an intermediate composition in addition to those available in the literature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Stone Content Influence on Land Surface Model Simulation of Soil Moisture and Evapotranspiration at Reynolds Creek Watershed

Considerable advancement in spatiotemporal resolution of remote sensing and ground-based measurements has enabled refinement of parameters used in land surface models for simulating surface water fluxes. However, land surface modeling capabilities are still inadequate for accurate representation of subsurface properties and processes, which continue to limit the accuracy of land surface model simulation. Our objective in this study was to examine the performance of the variously parameterized Noah-Multiphysics (Noah-MP) land surface model and to improve simulations of evapotranspiration (ET) and soil moisture dynamics in stony soils using verification from eddy covariance ET and in-situ soil moisture data. Meteorological and eddy covariance data from the Lower Sheep sub-catchment within the Reynolds Creek Experimental Watershed in Southwestern Idaho were employed to drive Noah-MP and to assess simulation results. We evaluated the performance of Noah-MP considering four different scenarios: (1) A one-layer soil profile with Noah-MP default soil hydraulic parameters, followed by five-layer soil profiles using -(2) Noah-MP default soil hydraulic parameters -(3) soil hydraulic parameters derived from a pedotransfer function using field observations, and -(4) hydraulic parameters from (3) which also accounted for stone content in each layer. Each modeling experiment was forced with the same set of initial conditions, atmospheric input and vegetation parameters. Our results indicated that enhanced representation of soil profile properties and stone content information noticeably improve the Noah-MP land surface model simulation of soil moisture content and evapotranspiration.

Land surface models, Soil hydrology, Noah-MP, Evap↗
DOE OSTI2016

Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Bulk density, grain size, carbon, and nitrogen content of floodplain fine sediment along the East River, Colorado collected from 2014 to 2017

The dataset is comprised of grain size, bulk density, carbon and nitrogen content of soils sampled on the floodplain of the East River 4 to 11 km downstream of Gothic, CO near Crested Butte. This dataset was collected to characterize the sedimentological properties and carbon inventory of the East River floodplain. The data help quantify the flux and storage of sediment and carbon between the East River and the alluvial floodplain bounding the river. The samples were collected between 2014 and 2017. The soil samples come from a total of 156 locations and were sampled in the upper 40 to 60 cm of the floodplain and in abandoned channel segments or oxbows. Not all samples were analyzed for all properties, but 26 samples were analyzed for bulk density, full particle size distribution, carbon, and nitrogen content. An additional 48 samples were analyzed for particle size fraction greater than and less than 2 mm and total organic content determined by loss on ignition. The dataset is comprised of a total of six separate data files based on the sample type and analysis and another file lists the sample identifications and locations of samples with a complete suite of analyses.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

G-LiHT Campaign Leaf Carbon and Nitrogen Content, Mar2017: Puerto Rico

Measurements of leaf carbon and nitrogen content collected from 68 tropical tree species. Data includes leaves collected from fully sunlit and shaded canopy strata as well as leaves for young, mature, old and senescent leaf ages. Data for each sample includes the relative age estimate, leaf canopy position and sample number. This data was collected as part of the 2017 NGEE-Tropics / NASA G-LiHT airborne campaign. This data package includes processed data for leaf carbon and nitrogen content (*.csv). Metadata files include data description (_dd.csv) for tabular data, site information (*.csv), sampling protocol (*.pdf) and the NGEE-Tropics FRAMES e-field log and file submission metadata (*.xlsx). See related datasets for sample details including photographs, leaf-level reflectance and transmittance spectra, leaf mass per area (LMA) and water content.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

G-LiHT Campaign Leaf Carbon and Nitrogen Content, Mar2017: Puerto Rico

Measurements of leaf carbon and nitrogen content collected from 68 tropical tree species. Data includes leaves collected from fully sunlit and shaded canopy strata as well as leaves for young, mature, old and senescent leaf ages. Data for each sample includes the relative age estimate, leaf canopy position and sample number. This data was collected as part of the 2017 NGEE-Tropics / NASA G-LiHT airborne campaign. This data package includes processed data for leaf carbon and nitrogen content (*.csv). Metadata files include data description (_dd.csv) for tabular data, site information (*.csv), sampling protocol (*.pdf) and the NGEE-Tropics FRAMES e-field log and file submission metadata (*.xlsx). See related datasets for sample details including photographs, leaf-level reflectance and transmittance spectra, leaf mass per area (LMA) and water content.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Low Noble Metal Content Catalysts/Electrodes for Hydrogen Production by Water Electrolysis

Commercial proton exchange membrane (PEM)-based electrolyzers require highly expensive catalyst materials such as platinum group metals due to the acidic environment of the membrane. However, by optimizing the catalyst electrode structure for high utilization and activity, the amount of catalyst required can be reduced to an acceptable amount for both lifecycle and capital cost. In this project, we aim to reduce the Pt content by two orders of magnitude in the cathode catalyst for hydrogen evolution reaction (HER) and significantly reduce the Ir content in the anode catalyst for oxygen evolution reaction (OER). Proton has developed a collaboration over the past year and a half with the BNL electrocatalysis group, which will provide key expertise in design and synthesis of core-shell nanocatalysts and innovative structure integration of catalyst synthesis and electrode fabrication. The Phase 1 STTR will focus on optimization of the cathode catalyst and electrode for the hydrogen evolution reaction, and identifying an effective approach for significantly improving anode performance for the OER with reduced noble metal content. The catalyst design will combine the most active, durable components with atomic-level control of core-shell structure and narrow particle size distribution to maximize specific surface area. The synthesis methods will be developed to produce high quality catalysts at low cost for large scale production. GDEs will be fabricated to maximize the catalyst utilization at the cathode. Proton will conduct performance and durability tests, evaluate the results against current state-of-the-art catalysts/electrodes, and will estimate the production costs including lifecycle costs using the H2A model.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Analysis of Joist Masonry Moisture Content Monitoring

There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw have known solutions. But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content & relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100% RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated vs. non-insulated joist pockets do not show large differences. South facing joists have safe (10-15%) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Hydrogenous Content in Residues from Aqueous Chloride Pu and Am Recovery Operations

Byproduct residues generated from Aqueous Chloride Pu and Am recovery operations at Los Alamos National Laboratory have been investigated and determined to contain high weight % chloride salts and minimal hydrogen content. Hydrogen content is the result of limited surface area adsorption of ambient moisture. The assumption used in technical analysis NCS-TECH-19-029 to model potentially hydrogenous items as mixtures of polyethylene is shown to be overly conservative. Our results and literature precedent indicate that water adsorption of 1-3 % by weight is expected for hydroxide cakes and Pu oxides, and a conservative bounding assumption for these materials is 5% water by weight. LOH results for a dissolution heel stored long term showed 6.25% weight loss, which was conservatively assumed to be water. A conservative bounding assumption for dissolution heels is 8 wt.% water content. This equates to 0.55 % hydrogen by weight for hydroxide cakes, and 0.88% hydrogen by weight for dissolution heels. The bulk composition of dissolution heels reflects the composition of the original byproduct feed material, chloride salts of potassium, sodium, magnesium and calcium. The bulk composition of calcined hydroxide precipitation residues is composed of potassium chloride as a result of potassium hydroxide neutralization of hydrochloric acid solutions. Metal hydroxides generated during the hydroxide precipitation process are decomposed under the conditions of calcination to metal oxide forms.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Knowledge Management Analysis for Content Migration

This Content Migration Plan provides a framework and methodology for managing and executing the migration of content to the NEFC Program’s on-premises SharePoint 2016 instance, as well as guidelines regarding how to ensure that Knowledge Management Program content, both during and after the migration, is tagged properly. Analysis continues to develop a migration plan for a SharePoint Online instance in a Cloud environment.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗