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All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Ultraviolet Imaging Telescope observations of the Cygnus Loop

Attention is given to UV images of a 40-arcmin field in the northeast part of the Cygnus Loop made by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 mission in December 1990. The longest FUV (B5) exposure is compared with ground-based and X-ray observations and with models. It is inferred from SNR shock models that C IV 1550 A dominates for more typical conditions in SNRs, and IUE spectra exhibit a strong correlation between C IV 1550-A flux and UIT B5 flux. The B5 image resembles images in forbidden O III 5007 A, but to the east of the edge of the forbidden O III filaments there is a faint C IV emission, consistent with nonradiative shocked material behind the SNR blast wave. Conditions in shocked gases that lead to C IV emission are similar to those that produce forbidden O III. Hence the ratio of the B5 and forbidden O III intensities can be used to map the optical depths of the sheetlike regions that emit the C IV resonance line.

Cornett, Robert H.↗
DOE OSTI2017

Base-pair opening dynamics of the microRNA precursor pri-miR156a affect temperature-responsive flowering in Arabidopsis

Internal and environmental cues, including ambient temperature changes, regulate the timing of flowering in plants. Arabidopsis miR156 represses flowering and plays an important role in the regulation of temperature-responsive flowering. However, the molecular basis of miR156 processing at lower temperatures remains largely unknown. Here, we performed nuclear magnetic resonance studies to investigate the base-pair opening dynamics of model RNAs at 16 °C and investigated the in vivo effects of the mutant RNAs on temperature-responsive flowering. The A9C and A10CG mutations in the B5 bulge of the lower stem of pri-miR156a stabilized the C15∙G98 and U16∙A97 base-pairs at the cleavage site of pri-miR156a at 16 °C. Consistent with this, production of mature miR156 was severely affected in plants overexpressing the A9C and A10CG constructs and these plants exhibited almost no delay in flowering at 16 °C. The A10G and A9AC mutations did not strongly affect C15∙G98 and U16∙A97 base-pairs at 16 °C, and plants overexpressing A10G and A9AC mutants of miR156 produced more mature miR156 than plants overexpressing the A9C and A10CG mutants and showed a strong delay in flowering at 16 °C. Interestingly, the A9AC mutation had distinct effects on the opening dynamics of the C15∙G98 and U16∙A97 base-pairs between 16 °C and 23 °C, and plants expressing the A9AC mutant miR156 showed only a moderate delay in flowering at 16 °C. Based on these results, we propose that fine-tuning of the base-pair stability at the cleavage site is essential for efficient processing of pri-miR156a at a low temperature and for reduced flowering sensitivity to ambient temperature changes. - Highlights: • A mutation in pri-miR156a B5 affected base-pairing stability at the cleavage site. • Mutations in the B5 bulge increased base-pair stabilities and decreased miR156. • The A9AC mutation affected opening dynamics between 16 and 23 °C. • Cleavage site base-pair stabilities reflected miR156 levels and flowering time.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

B2, B7 or B10: Which palm-based blend mandate wise to be chosen in Malaysia?

The diminishing fossil energy resources, coupled with heightened interest in the abatement of greenhouse gas emissions and concerns about energy security have motivated Malaysia to produce palm-based biodiesel and it has been started to be exported since 2006. In line with this issue, the government in Malaysia launched the palm-based biodiesel blending mandate of five percent (B5) in the federal administration of Putrajaya on 1{sup st} June 2011. This was then followed by four states: Malacca on July 11, Negeri Sembilan on August 1, Kuala Lumpur on September 1 and Selangor on October 1 of the same year but it is yet to be implemented nationwide. However what is the wise blend mandate to be chosen? Thus, this paper seeks to examine the possible impact of various blend mandates implementation (B2, B7 and B10) on the palm oil industry market variables (stock and price) since the main aim of biodiesel industry in Malaysia is to reduce domestic palm oil stock to below one million tones and provide a floor price to support Crude Palm Oil (CPO) prices at RM2,000 per tonne. A structural econometric model consisting of nine structural equations and three identities was proposed in this study. The model has been estimated by two stage least squares (2SLS) method using annual data for the period 1976-2013. The study indicates that counterfactual simulation of a decrease from B5 to B2 predicts a decrease (11.2 per cent) in CPO domestic consumption for biodiesel usage, 731.02 per cent reduction in CPO stock and an increase of 27.41 percent in domestic price of CPO. However the increase in the blend mandate from B5 to B7 and B10 suggest that domestic consumption of CPO for biodiesel purpose increase 7.40 and 18.55 percent respectively. The interesting findings in this study suggest that no matter whether Malaysian government increase or decrease the blend mandate the increase in the price of CPO are the same with an increase of is 27.41 percent. Hence, this study suggests that the lower blend mandate is the most favourable on.+-e compared to increasing it in this short period due to high production cost of CPO prices. However, future study on economic feasibility of palm-based biodiesel has to be conducted to support this study.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

Materials Data on B10Pb4O21 by Materials Project

(B5(PbO5)2)4O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two water molecules and one B5(PbO5)2 framework. In the B5(PbO5)2 framework, there are five inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.39 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.38 Å. In the third B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There is two shorter (1.47 Å) and two longer (1.49 Å) B–O bond length. In the fourth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.51 Å. In the fifth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.54 Å. There are two inequivalent Pb3+ sites. In the first Pb3+ site, Pb3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.37–2.99 Å. In the second Pb3+ site, Pb3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pb–O bond distances ranging from 2.33–2.93 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ and two Pb3+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two B3+ and one Pb3+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two B3+ and one Pb3+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ and two Pb3+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ and one Pb3+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Pb3+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two B3+ and one Pb3+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ and two Pb3+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ and one Pb3+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two B3+ and one Pb3+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2008

Quantitative Studies of the Optical and UV Spectra of Galactic Early B Supergiants

We undertake an optical and ultraviolet spectroscopic analysis of a sample of 20 Galactic B0-B5 supergiants of luminosity classes Ia, Ib, Iab, and II. Fundamental stellar parameters are obtained from optical diagnostics and a critical comparison of the model predictions to observed UV spectral features is made. Methods. Fundamental parameters (e.g., T(sub eff), log L(sub *), mass-loss rates and CNO abundances) are derived for individual stars using CMFGEN, a nLTE, line-blanketed model atmosphere code. The impact of these newly derived parameters on the Galactic B supergiant Ten scale, mass discrepancy, and wind-momentum luminosity relation is examined. Results. The B supergiant temperature scale derived here shows a reduction of about 1000-3000 K compared to previous results using unblanketed codes. Mass-loss rate estimates are in good agreement with predicted theoretical values, and all of the 20 BO-B5 supergiants analysed show evidence of CNO processing. A mass discrepancy still exists between spectroscopic and evolutionary masses, with the largest discrepancy occuring at log (L/(solar)L approx. 5.4. The observed WLR values calculated for B0-B0.7 supergiants are higher than predicted values, whereas the reverse is true for B1-B5 supergiants. This means that the discrepancy between observed and theoretical values cannot be resolved by adopting clumped (i.e., lower) mass-loss rates as for O stars. The most surprising result is that, although CMFGEN succeeds in reproducing the optical stellar spectrum accurately, it fails to precisely reproduce key UV diagnostics, such as the N v and C IV P Cygni profiles. This problem arises because the models are not ionised enough and fail to reproduce the full extent of the observed absorption trough of the P Cygni profiles. Conclusions. Newly-derived fundamental parameters for early B supergiants are in good agreement with similar work in the field. The most significant discovery, however, is the failure of CMFGEN to predict the correct ionisation fraction for some ions. Such findings add further support to revising the current standard model of massive star winds, as our understanding of these winds is incomplete without a precise knowledge of the ionisation structure and distribution of clumping in the wind. Key words. techniques: spectroscopic - stars: mass-loss - stars: supergiants - stars: abundances - stars: atmospheres - stars: fundamental parameters

Searle, S. C.↗
DOE OSTI2022

Biocatalytic system for comparatively assessing the functional association of monolignol cytochrome P450 monooxygenases with their redox partners

Lignin is a complex heterogenous polymer derived from oxidative radical polymerization of three monolignols, i.e., p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. These lignin monomeric precursors structurally differ in their methoxy groups of the benzene rings. In phenylpropanoid-monolignol biosynthetic pathway, the endoplasmic reticulum (ER)-resident cytochrome P450 monooxygenases, cinnamate 4-hydroxylase, coumaroyl ester 3´-hydroxylase and ferulate 5-hydroxylase, establish the key structural characteristics of monolignols. The catalysis of cytochrome P450 monooxygenase requires reducing power, which is supplied by the ER electron transfer chains, composed of cytochrome P450 oxidoreductase (CPR), cytochrome b5 reductase (CBR) and/or cytochrome b5 protein (CB5), from cofactor NADPH or NADH. While NADPH-dependent CPR serves as the typical electron donor for most P450 enzymes, in some cases, the CBR-CB5 or CPR-CB5 electron transfer system also transfers electrons to the terminal P450 enzymes. There are tremendous studies focusing on the discovery and characterization of cytochrome P450 monooxygenases. However, very limited attention has been paid to the versatility and the roles of electron transfer components in the P450 catalytic system. Due to the membrane-residence property of both P450 enzymes and electron transfer components, it is challenging to establish an effective experimental system to evaluate the functional association of P450s with their redox partners. This chapter describes a yeast cell biocatalytic system and the related experimental procedures for comparatively assessing the functional relationship of monolignol biosynthetic P450 enzymes and different redox partners in their catalysis.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Multi-scale boron penetration toward stabilizing nickel-rich cathode

Nickel-rich layered oxides LiNi x Co y Mn 1-x-y O 2 (x≥0.8) have been recognized as the preferred cathode materials to develop lithium-ion batteries with high energy density (>300Wh kg -1 ). However, the poor cycling stability and rate capability stemming from intergranular cracks and sluggish kinetics hinder their commercialization. To address such issues, a multi-scale boron penetration strategy is designed and applied on the polycrystalline LiNi 0.83 Co 0.11 Mn 0.06 O 2 particles that are pre-treated with pore construction. The lithium-ion conductive lithium borate in grain gaps functions as the grain binder that can bear the strain/stress from anisotropic contraction/expansion, and provides more pathways for lithium-ion diffusion. As a result, the intergranular cracks are ameliorated and the lithium-ion diffusion kinetics is improved. Moreover, the coating layer separates the sensitive cathode surface and electrolyte, helping to suppress the parasitic reactions and related gas evolution. In addition, the enhanced structural stability is acquired by strong B-O bonds with trace boron doping. As a result, the boron-modified sample with an optimized boron content of 0.5% (B5-NCM) exhibits a higher initial discharge capacity of 205.5mAh g -1 at 0.1C (1C=200mA g -1 ) and improved capacity retention of 81.7% after 100 cycles at 1C. Furthermore, the rate performance is distinctly enhanced by high lithium-ion conductive LBO (175.6mAh g -1 for B5-NCM and 154.6mAh g -1 for B0-NCM at 5C).

25 ENERGY STORAGE↗
DOE OSTI2025

New molecular components of high and low affinity iron import systems in Drosophila

The high abundance and molecular versatility of iron have led to its universal presence in biological systems, yet its absorption is exceptionally challenging. Animals and yeasts use divalent metal transporters to import iron, but yeasts also employ the multicopper oxidase Fet3p for high-affinity iron uptake when iron-starved. Using long-term iron depletion in Drosophila, we identified four components involved in iron absorption: Multicopper oxidase-4 (Mco4), a Fet3p ortholog, is essential for surviving iron starvation, whereas the cytochrome b561 enzymes Fire (Ferric Iron Reductase) and Fire-like, as well as cytochrome b5 protein Firewood, are required for iron absorption under normal conditions. This study reports the presence of a high-affinity iron uptake system in an animal, a cytochrome b5 electron donor for ferric iron reduction, and intestinal ferric reductases, and provides a valuable resource for further exploration of genes involved in iron homeostasis, transport, and absorption.

Iron↗
DOE OSTI2016

Effect of first and second generation biodiesel blends on engine performance and emission

The biodiesel is a potential source of alternative fuel which can be used at different proportions with diesel fuel. This study experimentally investigated the effect of blend percentage on diesel engine performance and emission using first generation (soybean) and second generation (waste cooking) biodiesel. The characterization of the biodiesel was done according to ASTM and EN standards and compared with ultralow sulfur diesel (ULSD) fuel. A multi-cylinder test bed engine coupled with electromagnetic dynamometer and 5 gas analyzer were used for engine performance and emission test. The investigation was made using B5, B10 and B15 blends for both biodiesels. The study found that brake power (BP) and brake torque (BT) slightly decreases and brake specific fuel consumption (BSFC) slightly increases with an increase in biodiesel blends ratio. Besides, a significant reduction in exhaust emissions (except NO{sub x} emission) was found for both biodiesels compared to ULSD. Soybean biodiesel showed better engine performance and emissions reduction compared with waste cooking biodiesel. However, NO{sub x} emission for B5 waste cooking biodiesel was lower than soybean biodiesel.

09 BIOMASS FUELS↗
DOE OSTI2014

Pyrethroid Activity-Based Probes for Profiling Cytochrome P450 Activities Associated with Insecticide Interactions

Pyrethroid insecticides are used to control a diverse spectrum of diseases spread by arthropods. We have developed a suite of pyrethroid mimetic activity based probes (PyABPs) to selectively label and identify P450s associated with pyrethroid metabolism. The probes were screened against pyrethroid metabolizing and non-metabolizing mosquito P450s, as well as rodent microsomes to measure labeling specificity, plus CPR and b5 knockout mouse livers to validate P450 activation and establish the role for b5 in probe activation. Using a deltamethrin mimetic PyABP we were able to profile active enzymes in rat liver microsomes and identify pyrethroid metabolizing enzymes in the target tissue. The most reactive enzyme was a P450, CYP2C11, which is known to metabolize deltamethrin. Furthermore, several other pyrethroid metabolizers were identified (CYPs 2C6, 3A4, 2C13 and 2D1) along with related detoxification enzymes, notably UDP-g’s 2B1 - 5, suggesting a network of associated pyrethroid metabolizing enzymes, or ‘pyrethrome’. Considering the central role that P450s play in metabolizing insecticides, we anticipate that PyABPs will aid the identification and profiling of P450s associated with insecticide pharmacology in a wide range of species, improving understanding of P450-insecticide interactions and aiding the development of new tools for disease control.

drug metabolism↗
DOE OSTI2019

Materials Data on CoB10H23C13 by Materials Project

CoB3C11H13B5(CH4)2(BH)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of eight boranediylradical molecules, four B5(CH4)2 clusters, and four CoB3C11H13 clusters. In each B5(CH4)2 cluster, there are five inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.73 Å. The B–H bond length is 1.20 Å. In the second B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.73 Å. The B–H bond length is 1.19 Å. In the third B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.71 Å. The B–H bond length is 1.19 Å. In the fourth B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.69 Å. The B–H bond length is 1.20 Å. In the fifth B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.68 Å. The B–H bond length is 1.20 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded in a 6-coordinate geometry to five B3+ and one C4- atom. The C–C bond length is 1.52 Å. In the second C4- site, C4- is bonded in a trigonal non-coplanar geometry to one C4- and three H+0.91+ atoms. All C–H bond lengths are 1.10 Å. There are eight inequivalent H+0.91+ sites. In the first H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the second H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the third H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the fourth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the fifth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the sixth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the seventh H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the eighth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In each CoB3C11H13 cluster, Co1+ is bonded in a 6-coordinate geometry to six C4- atoms. There are a spread of Co–C bond distances ranging from 2.06–2.19 Å. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.55 Å. The B–H bond length is 1.20 Å. In the second B3+ site, B3+ is bonded in a bent 120 degrees geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.55 Å. The B–H bond length is 1.20 Å. In the third B3+ site, B3+ is bonded in a water-like geometry to one C4- and one H+0.91+ atom. The B–C bond length is 1.76 Å. The B–H bond length is 1.20 Å. There are eleven inequivalent C4- sites. In the first C4- site, C4- is bonded in a 5-coordinate geometry to one Co1+, three B3+, and one C4- atom. The C–C bond length is 1.51 Å. In the second C4- site, C4- is bonded in a trigonal non-coplanar geometry to one C4- and three H+0.91+ atoms. All C–H bond lengths are 1.10 Å. In the third C4- site, C4- is bonded in a 4-coordinate geometry to one Co1+ and three C4- atoms. There are a spread of C–C bond distances ranging from 1.42–1.45 Å. In the fourth C4- site, C4- is bonded in a distorted single-bond geometry to one Co1+, one C4-, and one H+0.91+ atom. The C–H bond length is 1.09 Å. In the fifth C4- site, C4- is bonded in a distorted single-bond geometry to one Co1+ and one H+0.91+ atom. The C–H bond length is 1.09 Å. In the sixth C4- site, C4- is bonded in a distorted single-bond geometry to one Co1+, one C4-, and one H+0.91+ atom. The C–C bond length is 1.44 Å. The C–H bond length is 1.09 Å. In the seventh C4- site, C4- is bonded in a 4-coordinate geometry to one Co1+ and three C4- atoms. The C–C bond length is 1.42 Å. In the eighth C4- site, C4- is bonded in a distorted single-bond geometry to two C4- and one H+0.91+ atom. The C–C bond length is 1.38 Å. The C–H bond length is 1.09 Å. In the ninth C4- site, C4- is bonded in a distorted trigonal planar geometry to two C4- and one H+0.91+ atom. The C–C bond length is 1.43 Å. The C–H bond length is 1.09 Å. In the tenth C4- site, C4- is bonded in a distorted single-bond geometry to two C4- and one H+0.91+ atom. The C–C bond length is 1.38 Å. The C–H bond length is 1.09 Å. In the eleventh C4- site, C4- is bonded in a distorted trigonal planar geometry to two C4- and one H+0.91+ atom. The C–H bond length is 1.09 Å. There are thirteen inequivalent H+0.91+ sites. In the first H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the second H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the third H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one B3+ atom. In the fourth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the fifth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the sixth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the seventh H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the eighth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the ninth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the tenth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the eleventh H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the twelfth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom. In the thirteenth H+0.91+ site, H+0.91+ is bonded in a single-bond geometry to one C4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2010

Scaling solid resuspension and sorption for the small column ion exchange processing tank

The Small Column Ion Exchange (SCIX) process is being developed to remove cesium, strontium, and actinides from Savannah River Site (SRS) Liquid Waste using an existing 1.3 million gallon waste tank (i.e., Tank 41H) to house the process. Savannah River National Laboratory (SRNL) is conducting pilot-scale mixing tests to determine the pump requirements for suspending and resuspending Monosodium Titanate (MST), Crystalline Silicotitanate (CST), and simulated sludge. In addition, SRNL will also be conducting pilot-scale tests to determine the mixing requirements for the strontium and actinide sorption. As part of this task, the results from the pilot-scale tests must be scaled up to a full-scale waste tank. This document describes the scaling approach. The pilot-scale tank is a 1/10.85 linear scale model of Tank 41H. The tank diameter, tank liquid level, pump nozzle diameter, pump elevation, and cooling coil diameter are all 1/10.85 of their dimensions in Tank 41H. The pump locations correspond to the proposed locations in Tank 41H by the SCIX Program (Risers B5 and B2 for two pump configurations and Risers B5, B3, and B1 for three pump configurations). MST additions are through Riser E1, the proposed MST addition riser in Tank 41H. To determine the approach to scaling the results from the pilot-scale tank to Tank 41H, the authors took the following approach. They reviewed the technical literature for methods to scale mixing with jets and suspension of solid particles with jets, and the technical literature on mass transfer from a liquid to a solid particle to develop approaches to scaling the test data. SRNL assembled a team of internal experts to review the scaling approach and to identify alternative approaches that should be considered.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

Investigating suspension of mst slurries in a pilot-scale waste tank

The Small Column Ion Exchange (SCIX) process is being developed to remove cesium, strontium, and actinides from Savannah River Site (SRS) Liquid Waste using an existing waste tank (i.e., Tank 41H) to house the process. Savannah River National Laboratory (SRNL) is conducting pilot-scale mixing tests to determine the pump requirements for suspending monosodium titanate (MST), crystalline silicotitanate (CST), and simulated sludge. The purpose of this pilot scale testing is for the pumps to suspend the MST particles so that MST can be removed from the tank. The pilot-scale tank is a 1/10.85 linear scaled model of Tank 41H. The tank diameter, tank liquid level, pump nozzle diameter, pump elevation, and cooling coil diameter are all 1/10.85 of their dimensions in Tank 41H. The pump locations correspond to the proposed locations in Tank 41H by the SCIX program (Risers B5 and B2 for two pump configurations and Risers B5, B3, and B1 for three pump configurations).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1983

The rotational velocities of a sample of Herbig Ae/Be stars

Rotational velocity estimates are presented for 15 Herbig Ae/Be stars. Those objects with nominal optical spectral types between B5 and A0 show a frequency distribution of v sin i values significantly different from that of normal Be stars in this spectral type range; the Herbig emission stars must have significantly smaller intrinsic rotational velocities. Herbig emission stars of types B0-B5 cannot be distinguished from normal Be stars on the basis of rotational velocity alone.

Davis, R.↗
NASA NTRS1984

Dense cores in dark clouds - Young embedded stars at 2 micrometers

Twenty-five visually opaque regions which contain strong sources of NH3 (1,1) line emission (dense cores) have been surveyed for evidence of associated stars at two microns. Five such stars have been found, of which three - in B5, L1489, and L1582 - are optically invisible and probably embedded in their associated cores. The stars in B5 and L1489 have 2-100 micron spectra and luminosity similar to those of HL Tau, a very young T Tauri star. These stars probably formed in the cores where they are now seen. These results tend to confirm earlier suggestions that low-mass stars form in dense cores.

Benson, P. J.↗
NASA NTRS1992

The orbital parameters and the IUE spectrum of the single-lined spectroscopic binary HD 698

IUE observations of the spectroscopic binary HD 698 show that its continuous spectrum corresponds to that of a B5 III-II object and that, even in the ultraviolet, the object is single-lined. The spectrum displays several sets of lines, all in absorption, where features can be distinguished that partake of the orbital motion of the B5 component, lines that suggest the existence of nonthermal sources of energy, and lines that form at the boundary of the circumstellar envelope, part of them being of purely interstellar origin. The circumbinary envelope appears to expand and then starts decelerating before the layer is reached where the resonance doublet of Si IV originates. The 'discrete absorptions' that are characteristics of the spectra of early-type stars are present in the spectrum. New values of the orbital period and of the rest of the orbital parameters are determined on the basis of all the available ground-based data.

Sahade, Jorge↗
NASA NTRS1994

ROSAT HRI observations of hot stars in the Orion Nebula

ROSAT High Resolution Interferometer (HRI) observations of hot (O6-A5) stars in the Orion Nebula region are presented. Fourteen of 21 O6-B5 stars were detected and all of them appear to have X-ray luminosities and L(sub x)/L(sub bol) ratios similar to field O6-B5 stars. The brightest star in the Trapezium, the O7 V star theta(sup 1) C Ori, has notable variation in its X-ray emission; the variation seems to have the same phase dependence as recently found for the star's hydrogen alpha emission. A maximum of six of 27 B6-A5 stars observed were detected; we argue that the most likely explanation for their X-ray emission is that it arises from unseen, low-mass binary companions.

Caillault, Jean-Pierre↗
NASA NTRS1999

Ultraviolet, Optical and X-Ray Imaging of Selected Cygnus Loop Fields

During the Astro-1 and Astro-2 Space Shuttle missions in 1990 and 1995, far ultraviolet (FUV) images of five 40 ft diameter fields around the rim of the Cygnus Loop Super Nova Remnants (SNR) were observed with the Ultraviolet Imaging Telescope (UIT). These fields sample a broad range of SNR conditions including both radiative and non-radiative shocks in various geometries and scales. The UIT B5 band images discussed here sample predominantly ion-C4 lambda 1550 and the 2-photon continuum. Smaller contributions are made by emission lines of ion He-2 lambda 1640 and ion 03 lambda 1666. A unique aspect of the B5 band is its ability to sample the hydrogen 2-photon continuum from regions where the gas is recombining. We present these new FUV images and compare them with optical H-alpha and [ion O13], and ROSAT HRI X-ray images. In non-radiative shocks, existing 2-photon flux measurements from spectra and the H-alpha images suggest we are seeing approximately equal contributions from 2-photon and ion C4 emission. In radiative filaments, however, shock models and our images suggest ion C4 should dominate while spectra of specific locations seem to indicate that 2-photon emission dominates. We surmise that spectral observations on specific bright filaments have decreased locally-observed levels of ion C41 emission due to resonance scattering in that line.

Danforth, C. W.↗