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Results for “LU factorization”

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

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Influence of site and soil properties on the DRIFT spectra of northern cold-region soils [Influence of site and soil properties on the mid-infrared spectra of northern cold-region soils]

Here, we investigated the influence of site characteristics and soil properties on the chemical composition of organic matter in soils collected from a latitudinal transect across Alaska through analysis of diffuse reflectance Fourier transform mid infrared (MidIR) spectra of bulk soils. The study included 119 soil samples collected from 28 sites including tundra, boreal forest, and grassland ecosystems. Organic, mineral, and cryoturbated soil horizons, both seasonally and perennially frozen, from a variety of depths and edaphic conditions were examined. The amount and chemical composition of organic matter as well as site and soil properties exerted a strong influence on the MidIR spectra. The spectra were highly sensitive to the extent of organic matter decomposition, enabling the ordination of Oi, Oe and Oa organic horizons. Differences in absorbance intensity for several spectral bands indicated that Oi horizons contained greater abundance of relatively fresh residues, phenolic-OH compounds, aliphatic compounds (waxes, lipids and fats), and carbohydrates. In contrast, Oa horizons had a greater presence of amide groups (possibly from microbial residues), aromatics, C=C bonds, carboxylates and carboxylic acids. Another significant factor differentiating these horizons was the incorporation of clays and silicates into the decomposing organic matter of Oa horizons. Calculated height peak ratios showed a clear trend to greater decomposition among Oi, Oe and Oa. The MidIR spectra were related to many site/soil attributes including land cover type, parent material, and associated factors, such as permafrost presence/absence, soil drainage, horizon depth, bulk density, cation exchange capacity, and pH. Single MidIR spectral bands were identified that might be used in future studies to quickly estimate the organic and inorganic carbon, total nitrogen, and carbon:nitrogen ratios of soils from northern latitudes. Lastly, our results demonstrate that the information contained in MidIR spectra of bulk soil integrates the quantity and chemical composition of soil organic matter with soil forming factors and highlights the potential for using this information to assess the degradation state of organic matter stored in northern cold-region soils.

58 GEOSCIENCES↗
DOE OSTI2017

Monte Carlo simulations of time-of-flight PET with double-ended readout: calibration, coincidence resolving times and statistical lower bounds

Here, this paper demonstrates through Monte Carlo simulations that a practical positron emission tomograph with (1) deep scintillators for efficient detection, (2) double-ended readout for depth-of-interaction information, (3) fixed-level analog triggering, and (4) accurate calibration and timing data corrections can achieve a coincidence resolving time (CRT) that is not far above the statistical lower bound. One Monte Carlo algorithm simulates a calibration procedure that uses data from a positron point source. Annihilation events with an interaction near the entrance surface of one scintillator are selected, and data from the two photodetectors on the other scintillator provide depth-dependent timing corrections. Another Monte Carlo algorithm simulates normal operation using these corrections and determines the CRT. A third Monte Carlo algorithm determines the CRT statistical lower bound by generating a series of random interaction depths, and for each interaction a set of random photoelectron times for each of the two photodetectors. The most likely interaction times are determined by shifting the depth-dependent probability density function to maximize the joint likelihood for all the photoelectron times in each set. Example calculations are tabulated for different numbers of photoelectrons and photodetector time jitters for three 3 × 3 × 30 mm 3 scintillators: Lu 2 SiO 5 :Ce,Ca (LSO), LaBr 3 :Ce, and a hypothetical ultra-fast scintillator. To isolate the factors that depend on the scintillator length and the ability to estimate the DOI, CRT values are tabulated for perfect scintillator-photodetectors. For LSO with 4000 photoelectrons and single photoelectron time jitter of the photodetector J = 0.2 ns (FWHM), the CRT value using the statistically weighted average of corrected trigger times is 0.098 ns FWHM and the statistical lower bound is 0.091 ns FWHM. For LaBr 3 :Ce with 8000 photoelectrons and J = 0.2 ns FWHM, the CRT values are 0.070 and 0.063 ns FWHM, respectively. For the ultra-fast scintillator with 1 ns decay time, 4000 photoelectrons, and J = 0.2 ns FWHM, the CRT values are 0.021 and 0.017 ns FWHM, respectively. Lastly, the examples also show that calibration and correction for depth-dependent variations in pulse height and in annihilation and optical photon transit times are necessary to achieve these CRT values.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Temperature dependent thermoelectric properties of cuprous delafossite oxides

The use of nanostructured delafossite oxides in thermoelectric (TE) applications has attracted a great interest due to their high performance and long-term stability at elevated temperatures. Cuprous delafossites, CuMO 2 (M=Al, Cr, Fe, Ga, Mn), compared to conventional TE materials, such as Bi 2 Te 3 , PbTe and SiGe, are non-toxic and more earth abundant. In particular, CuAlO 2 compound shows a great potential for high performance thermoelectric materials. In this work, a systematic study of temperature dependent TE properties of cuprous delafossite materials, CuAlO 2 , is reported. The optimization of the TE properties has been realized by controlling nanostructure size around 80 nm CuAlO 2 powder was prepared using a solid-state synthesis method at ~1373 K in nitrogen/air atmosphere. The nanostructure size was controlled by a high energy ball milling process. Reducing the particle size of nanostructured bulk materials decouples interdependent electron and phonon transport and results in a lattice thermal conductivity decrease without deteriorating electrical conductivity. As a result, the high effective mass plays a dominant role in the high Seebeck coefficient and low electrical conductivity. The power factor reached ~0.78×10 -5 W/mK 2 at 780 K. Temperature dependent TE properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity are analyzed. The processing-structure-property correlation of these materials are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Study on aggregation and electric properties in the micro-region of functionalized dithieno[2, 3-b: 3′, 2′-d]thiophene (DTT) oligomers

Three kinds of 2,5,-diphenyl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DP-DTT), 2,5,-distyryl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DEP-DTT) and 2,5,-thienyl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DET-DTT) micro-region structure and electronic properties were studied. Thin films of these functionalized DTT oligomers were prepared in a one-step drop-casting deposition onto highly oriented pyrolytic graphite substrates. The surface structure of these films was characterized by atomic force microscopy (AFM). Conducting probe atomic force microscope (C-AFM) and Kelvin probe force microscope (KFM) were both used to characterize the electronic transport behavior and surface potential distribution. The substituents of DTT oligomers can greatly affect their aggregation and the hopping conductance mechanism was used to explain the Au-DTTs-HOPG junctions. KFM investigation revealed that these oligomers with different substituents have different highest occupied molecular orbital energy levels. The corresponding theoretical analysis reveals similar result to KFM characterization. The I-V results indicated that the aggregates of molecules were the dominating factor to their micro-region electrical transport.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Lnc-SNHG1 may promote the progression of non-small cell lung cancer by acting as a sponge of miR-497

Highlights: • lnc-SNHG1 promotes the progression of non-small cell lung cancer(NSCLC). • lnc-SNHG1 might modulate cell proliferation, migration and invasion by sponging miR-497. • The effect of lnc-SNHG1 on NSCLC could be rescued by miR-497. • lnc-SNHG1 promotes cancer cell motility in a miR-497-dependent manner via IGF1-R. Lnc-SNHG1 (small nucleolar RNA host gene 1) is considered an important regulating factor in several types of cancers. However, the biological functions and underlying molecular mechanisms in which lnc-SNHG1 is involved in non-small cell lung cancer (NSCLC) still need to be explored. In this study, we investigated the detailed effects and possible molecular mechanisms. The transcript level of lnc-SNHG1 was higher in lung adenocarcinoma specimens and NSCLC cell lines than in noncancer tissue and cells. The level of expression was positively correlated with invasiveness and was negatively correlated with the level of miR-497 in vivo and in vitro. In exploring the regulatory mechanism, we found that lnc-SNHG1 might modulate tumor growth by sponging miR-497. The inhibitory effect of si-lnc-SNHG1 on NSCLC cell proliferation, migration and invasion could be rescued by miR-497 inhibition, while the overexpression of miR-497 could reverse the effect of lnc-SNHG1 overexpression. Furthermore, our study demonstrated that the lnc-SNHG1 regulated the expression of the insulin-like growth factor 1 receptor (IGF1-R) by acting as a sponge of miR-497 in NSCLC. lnc-SNHG1 could be a novel biomarker as well as a curative target.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

N-oleoylethanolamide suppresses intimal hyperplasia after balloon injury in rats through AMPK/PPARα pathway

Highlights: • OEA alleviates intimal hyperplasia induced by balloon injury. • OEA suppresses VSMC proliferation and migration. • OEA modulats VSMC proliferation and migration partly through AMPK- PPARα pathway. Vascular smooth muscle cell (VSMC) proliferation and migration are crucial events in the pathological course of restenosis after percutaneous coronary intervention (PCI). N-oleoylethanolamide (OEA) is a bioactive lipid amide released upon dietary fat digestion with many reported actions. However, the effect of OEA on restenosis after vascular injury remains unknown. Here, we investigated the effects of OEA on intimal hyperplasia after balloon injury in vivo, its effect on VSMC proliferation and migration induced by platelet-derived growth factor (PDGF) stimulation in vitro, and the underlying mechanism underlying these effects. The results showed that OEA-treated rats displayed a significant reduction in neointima formation after balloon injury. In cultured VSMCs, treatment with OEA decreased cell proliferation and migration induced by PDGF. OEA treatment both in vivo and in vitro led to an increase in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and peroxisome proliferator-activated receptor alpha (PPARα), and a decrease in proliferating cell nuclear antigen (PCNA) and cyclinD1 expression. Pharmacological inhibition of AMPK and PPARα reversed the suppressive effects of OEA on VSMC proliferation and migration, suggesting that the suppressive effect of OEA on VSMC proliferation and migration is mediated through the activation of AMPK and PPARα. In conclusion, our present study demonstrated that OEA attenuated neointima formation in response to balloon injury by suppressing SMC proliferation and migration through an AMPK and PPARα-dependent mechanism. Our data suggests that OEA may be a potential therapeutic agent for restenosis after PCI.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Low expression level of HMBOX1 in high-grade serous ovarian cancer accelerates cell proliferation by inhibiting cell apoptosis

Highlights: • HMBOX1 was significantly downregulated in HGSOC tissues and ovarian cancer cell lines. • There was a negative correlation between the expression of HMBOX1 and cell proliferation of ovarian cancer cell lines. • HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. • HMBOX1 downregulated the expression of Bcl-2, Bcl-xL and upregulated that of Bad, Bax and Caspase3. Homeobox-containing 1 (HMBOX1) has been described as a transcription factor involved in the occurrence of some tumors, but its roles in ovarian cancer have never been reported. Here we aimed to investigate the roles of HMBOX1 on high-grade serous ovarian carcinoma (HGSOC). In this present study, HMBOX1 expression was decreased in HGSOC tissues and ovarian cancer cell lines (HO8910 and A2780) compared with ovarian surface epithelial tissues or normal human ovarian surface epithelial cell line (HOSEpiC). The cell proliferation of HOSEpiC was weaker than ovarian cancer cell lines. By altering the expression of HMBOX1 in A2780 and HOSEpiC, we demonstrated that HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. Furthermore, our study revealed that HMBOX1 downregulated the expression of anti-apoptotic proteins (Bcl-2, Bcl-xL), raised the expression of pro-apoptotic-regulated proteins (Bad, Bax), apoptotic executionior (Caspase3), and P53. In conclusion, HMBOX1 played important roles in occurrence of HGSOC through regulation of proliferation and apoptosis, which implied that HMBOX1 might serve as a new therapeutic target for HGSOC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Velocity Dispersion σ aper Aperture Corrections as a Function of Galaxy Properties from Integral-field Stellar Kinematics of 10,000 MaNGA Galaxies

Abstract The second moment of the stellar velocity within the effective radius, denoted by σ e 2 , is a crucial quantity in galaxy studies, as it provides insight into galaxy properties and their mass distributions. However, large spectroscopic surveys typically do not measure σ e directly, instead providing σ aper , the second moment of the stellar velocity within a fixed fiber aperture. In this paper, we derive an empirical aperture correction formula, given by σ aper / σ e = ( R aper / R e ) α , using spatially resolved stellar kinematics extracted from approximately 10,000 Sloan Digital Sky Survey–Mapping Nearby Galaxies at Apache Point Observatory integral field unit observations. Our analysis reveals a strong dependence of α on the r -band absolute magnitude M r , g – i color, and Sérsic index n Ser , where α values are lower for brighter, redder galaxies with higher Sérsic indices. Our results demonstrate that the aperture correction derived from previous literature on early-type galaxies cannot be applied to predict the aperture corrections for galaxies with intermediate Sérsic indices. We provide a lookup table of α values for different galaxy types, with parameters in the ranges of −18 > M r > −24, 0.4 < g – i < 1.6, and 0 < n Ser < 8. A Python script is provided to obtain the correction factors from the lookup table.

Astronomy & Astrophysics↗
DOE OSTI2019

Nucleon-to-Roper electromagnetic transition form factors at large Q 2

High-precision nucleon-resonance electroproduction data on a large kinematic domain of energy and momentum transfer have proven crucial in revealing novel features of strong interactions within the Standard Model and unfolding structural details of baryon excited states. Thus, in anticipation of new data reaching to unprecedented photon virtuality, we employ a quark-diquark approximation to the three-valence-quark bound-state problem to compute γ*p → R + and γ*n → R 0 transition form factors on Q 2 /m 2 N ϵ[0,12], where m N is the nucleon mass. Having simultaneously analyzed both charged and neutral channels, we also provide a quark-flavor separation of the transition form factors. Furthermore, the results should be useful in planning new-generation experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Identification of a secretory heme‐binding protein from Nocardia seriolae involved in cell apoptosis

Abstract According to the whole‐genome bioinformatics analysis, a heme‐binding protein from Nocardia seriolae (HBP) was found. HBP was predicted to be a bacterial secretory protein, located at mitochondrial membrane in eukaryotic cells and have a similar protein structure with the heme‐binding protein of Mycobacterium tuberculosis , Rv0203. In this study, HBP was found to be a secretory protein and co‐localized with mitochondria in FHM cells. Quantitative analysis of mitochondrial membrane potential value, caspase‐3 activity, and transcription level of apoptosis‐related genes suggested that overexpression of HBP protein can induce cell apoptosis. In conclusion, HBP was a secretory protein which may target to mitochondria and involve in cell apoptosis in host cells. This research will promote the function study of HBP and deepen the comprehension of the virulence factors and pathogenic mechanisms of N. seriolae .

Wen, Yiming↗
DOE OSTI2022

Full-scale FEED Study for Retrofitting the Prairie State Generating Station with an 816 MWe Capture Plant using Mitsubishi Heavy Industries Post-Combustion CO 2 Capture Technology

A full front-end engineering design (FEED) study to for a carbon capture system for Unit #2 (816 MWe) at the Prairie State Generating Company’s (PSGC) Energy Campus in Marissa, IL based on the KM CDR Process CO 2 capture technology from Mitsubishi Heavy Industries (MHI) using their proprietary solvent KS-21TM. If built this carbon capture plant would be the world's largest to date. The cost of capture of 100 percent of the plant emissions was calculated to be $43.42 per metric tonne of CO 2 based on levelized costs for 30 years of operation (85% capacity factor), and includes Interest on Debt and Return on Equity During Operation.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Maximize, minimize or target - optimization for a fitted response from a designed experiment

One of the common goals of running and analyzing a designed experiment is to find a location in the design space that optimizes the response of interest. Depending on the goal of the experiment, we may seek to maximize or minimize the response, or set the process to hit a particular target value. After the designed experiment, a response model is fitted and the optimal settings of the input factors are obtained based on the estimated response model. Furthermore, the suggested optimal settings of the input factors are then used in the production environment.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Novel Hsp90 inhibitor platycodin D disrupts Hsp90/Cdc37 complex and enhances the anticancer effect of mTOR inhibitor

Heat shock protein 90 (Hsp90) is a critically conserved molecular chaperone protein and promising therapeutic target for cancer treatment. In this study, platycodin D (PD), a saponin isolated from traditional Chinese herb Platycodonis Radix, was identified as a novel Hsp90 inhibitor. We verified that PD did not affect the ATPase activity of Hsp90. However, PD disrupted the co-chaperone interaction of Hsp90/cell division cycle protein 37 (Cdc37) and subsequently degraded multiple Hsp90 client proteins without the feedback increase of Hsp70. In different genotypes of non-small cell lung cancer cells, co-treatment with the mTOR inhibitor Everolimus and PD enhanced antiproliferation activity and apoptotic effect. The feedback survival signal upon mTOR inhibition was fully terminated by the co-administration with PD through reduced epidermal growth factor receptor (EGFR) and insulin growth factor 1 receptor (IGF1R) expression, suppressed AKT activity, and reinforced 4E-BP1 inhibition. Our results not only identified PD as a novel Hsp90 inhibitor by disrupting the protein–protein interaction of Hsp90/Cdc37 complex, but also provided mechanistic insights into the ineffectiveness of mTOR inhibitors and identified therapeutic strategy for cancer treatment. - Highlights: • Platycodin D (PD) is a novel Hsp90 inhibitor by disrupting Hsp90/Cdc37 complex. • PD terminated the survival signal induced by mTOR inhibition via feedback blockade. • Combining mTOR inhibitor and PD together exhibited amplified anti-NSCLC effect.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

High-Q silicon carbide photonic-crystal cavities

We demonstrate one-dimensional photonic-crystal nanobeam cavities in amorphous silicon carbide. The fundamental mode exhibits intrinsic optical quality factor as high as 7.69 × 10{sup 4} with mode volume ∼0.60(λ/n){sup 3} at wavelength 1.5 μm. A corresponding Purcell factor value of ∼10{sup 4} is the highest reported to date in silicon carbide optical cavities. The device exhibits great potential for integrated nonlinear photonics and cavity nano-optomechanics.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Simultaneously Enhancing Exciton/Charge Transport in Organic Solar Cells by an Organoboron Additive

Efficient exciton diffusion and charge transport play a vital role in advancing the power conversion efficiency (PCE) of organic solar cells (OSCs). Here, a facile strategy is presented to simultaneously enhance exciton/charge transport of the widely studied PM6:Y6-based OSCs by employing highly emissive trans-bis(dimesitylboron)stilbene (BBS) as a solid additive. BBS transforms the emissive sites from a more H-type aggregate into a more J-type aggregate, which benefits the resonance energy transfer for PM6 exciton diffusion and energy transfer from PM6 to Y6. Transient gated photoluminescence spectroscopy measurements indicate that addition of BBS improves the exciton diffusion coefficient of PM6 and the dissociation of PM6 excitons in the PM6:Y6:BBS film. Transient absorption spectroscopy measurements confirm faster charge generation in PM6:Y6:BBS. Moreover, BBS helps improve Y6 crystallization, and current-sensing atomic force microscopy characterization reveals an improved charge-carrier diffusion length in PM6:Y6:BBS. Finally, owing to the enhanced exciton diffusion, exciton dissociation, charge generation, and charge transport, as well as reduced charge recombination and energy loss, a higher PCE of 17.6% with simultaneously improved open-circuit voltage, short-circuit current density, and fill factor is achieved for the PM6:Y6:BBS devices compared to the devices without BBS (16.2%).

14 SOLAR ENERGY↗