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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Binary phase correlated X-ray intensity variations and flaring activity in the RS CVn binary HR 1099

The monitor proportional counter and the imaging proportional counter of the Einstein Observatory were used to observe the X-ray variability of the RS CVn binary HR 1099. The X-ray intensity is found to vary with the 2.837-day period of the binary. An intense X-ray flare was noted on February 17, 1980. The present results are explained using a star spot model, and it is suggested that the flare heated plasma cools either mainly by radiation or equally by conduction and radiation.

Agrawal, P. C.↗
NASA NTRS1993

Binary star orbits from speckle interferometry. 5: A combined speckle/spectroscopic study of the O star binary 15 Monocerotis

We report on the discovery of a speckle binary companion to the O7 V (f) star 15 Monocerotis. A study of published radial velocities in conjunction with new measurements from Kitt Peak National Observatory (KPNO) and IUE suggests that the star is also a spectroscopic binary with a period of 25 years and a large eccentricity. Thus, 15 Mon is the first O star to bridge the gap between the spectroscopic and visual separation regimes. We have used the star's membership in the cluster NGC 2264 together with the cluster distance to derive masses of 34 and 19 solar mass for the primary and secondary, respectively. Several of the He I line profiles display a broad shallow component which we associate with the secondary, and we estimate the secondary's classification to be O9.5 Vn. The new orbit leads to several important predictions that can be tested over the next few years.

Gies, Douglas R.↗
NASA NTRS2017

Unusual Black Hole Binary LMC X-3: A Transient High-Mass X-Ray Binary That Is Almost Always On?

We have analyzed a rich, multimission, multiwavelength data set from the black hole X-ray binary (BHXB) LMC X-3, covering a new anomalous low state (ALS), during which the source flux falls to an unprecedentedly low and barely detectable level, and a more normal low state. Simultaneous X-ray and UV/optical monitoring data from Swift are combined with pointed observations from the Rossi X-ray Timing Explorer (RXTE) and X-ray Multi- Mirror Mission (XMM-Newton) and light curves from the Monitor of All-Sky X-ray Image (MAXI) instrument to compare the source characteristics during the ALS with those seen during the normal low state. An XMM-Newton spectrum obtained during the ALS can be modeled using an absorbed power law with Gamma = 1.41‚+/- 0.65 and a luminosity of 7.97 x 10(exp 33) erg/s (0.6-5 keV). The Swift X-ray and UV light curves indicate an X-ray lag of approx. 8 days as LMC X-3 abruptly exits the ALS, suggesting that changes in the mass accretion rate from the donor drive the X-ray lag. The normal low state displays an asymmetric profile in which the exit occurs more quickly than the entry, with minimum X-ray flux a factor of approx. 4300 brighter than during the ALS. The UV brightness of LMC X-3 in the ALS is also fainter and less variable than during normal low states. The existence of repeated ALSs in LMC X-3, as well as a comparison with other BHXBs, implies that it is very close to the transient/persistent X-ray source dividing line. We conclude that LMC X-3 is a transient source that is almost always "on."

Simultaneous X-ray and UV/optical monitoring dat↗
DOE OSTI2022

Bubble Point Measurements of Three Binary Mixtures of Refrigerants: R-32/1234yf, R-32/1234ze(E), and R-1132a/1234yf

In this article, bubble point pressures of three binary mixtures at two compositions each have been measured utilizing a static method. The mixtures studied were difluoromethane + 2,3,3,3-tetrafluoroprop-1-ene (R-32/1234yf), difluoromethane + (E)-1,3,3,3-tetrafluoroprop-1-ene (R-32/1234ze(E)), and 1,1-difluoroethene + 2,3,3,3-tetrafluoroprop-1-ene (R-1132a/1234yf). For all of the mixtures, the minimum temperature measured was 270 K. The maximum temperatures measured for the R-32/1234ze(E), R-32/1234yf, and R-1132a/1234yf mixtures were 360, 345, and 325 K, respectively. A total of 100 bubble point pressures are reported and compared to available literature data relative to the REFPROP database. Lemmon, E. W. [ NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, 10.0; National Institute of Standards and Technology, Standard Reference Data Program: Gaithersburg, 2018]. Additionally, the bubble point pressures obtained in this study are modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. The PC-SAFT model parameters, as well as deviations of this work and literature data from the model, are reported.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Ultrasound-Assisted Nonthermal, Nonequilibrium Separation of Organic Molecules from Their Binary Aqueous Solutions: Effect of Solute Properties on Separation

The separation of organic molecules in downstream processes, such as distillation, plays a vital role in biobased chemical production. A comprehensive study was performed here using ultrasonic energy to separate 11 organic molecules from their binary aqueous solutions under nonthermal, nonequilibrium, and phase-change free conditions. A batch sonoseparator with a three-stage mist collection unit allowed direct analysis of ultrasound-generated mist with an HPLC/GC and differentiation and quantification of the vapor and mist. The results showed that the alcohols (1-butanol, ethanol, 1-propanol, and methanol) and acetone were enriched in the ultrasound-generated mist with enrichment ratios of 3.2–5. On the other hand, ethylene glycol, glycerol, γ-valerolactone (GVL), glucose, and sucrose were diluted with dilution ratios in the range of 2.04–15.7 in the mist and vapor generated by ultrasound (or concentrated in the bulk solution). No enrichment nor dilution of acetic acid was observed. The role of various physicochemical parameters such as dynamic viscosity, surface tension, Henry’s law of solubility constant, vapor pressure, and octanol–water partition coefficient in the enrichment was examined. Furthermore, the hydrophobicity of the organic molecules represented by the octanol–water partition coefficient was found to play a crucial role in determining the separation characteristics of the molecules in ultrasound-generated mist and vapor.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

From binary to quaternary: high-tolerance of multi-acceptors enables development of efficient polymer solar cells [From binary to quaternary: high-tolerance of multi-acceptors enables efficient polymer solar cells]

For optimum coverage of the optical spectrum and further enhancement of the carrier transport, ternary and even more multi-composition strategies have been universally explored. As PC 71 BM and PC 61 BM are both compatible with PTB7-Th and IEICO-4F takes advantage of optical absorption in the near-infrared region, we combined PTB7-Th:IEICO-4F:PC 71 BM:PC 61 BM quaternary compositions to fabricate high-efficiency polymer solar cells (PSCs) with good tolerance ratios of the fullerene acceptors. After blending the fullerene alloys PC 71 BM and PC 61 BM into the host PTB7-Th:IEICO-4F system, the optical response in the whole wavelength regime has been strengthened with significantly enhanced electron mobility. Concomitantly, the short-circuit current density ( J sc ) surged from 22.07 to 24.37 mA cm –2 and the fill factor (FF) ascended from 58.24% to 69.30%, which finally resulted in a champion power conversion efficiency (PCE) of 12.52%, which is much higher than that of the binary control device (9.67%). This significant improvement is attributed to the fine-tuning of the morphology of the photo-active layer and feasible carrier transport. Interestingly, this finding implicates the synergistic effect of PC 71 BM and PC 61 BM to successfully enhancing the carrier transport. In addition, it demonstrates a broad tolerance of the acceptor proportions, resulting in higher PCE values for the quaternary devices as compared to the ternary devices. Lastly, generality for other systems evidences and provides guidelines for quaternary strategy utilization. Furthermore, the simplicity of quaternary strategies could be greatly beneficial to not yet elaborate commercial processes.

14 SOLAR ENERGY↗
NASA NTRS1984

Binary modulation and transient periodic variations in X-ray emission from the AM Her binary H 0139 - 68

A detailed timing analysis of HEAO-1 and Einstein satellite soft X-ray data on the AM Her-type binary H 0139 - 68 indicates that the X-ray flux is modulated at the 113.6363-min period of its optical counterpart, and that the X-ray source shows high and low states. Transient X-ray pulsations with a period of about 275 sec are noted in the Imaging Proportional Counter (IPC) data during the high state, and the rapid X-ray flickering observed in the IPC light curve is characterized by an average e-folding autocorrelation time of about 10-20 sec. The present optical and X-ray data preclude the presence of an accretion disk in the primary system.

Singh, K. P.↗
NASA NTRS1993

Fabricating binary optics: An overview of binary optics process technology

A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.

Stern, Margaret B.↗
NASA NTRS1995

Spectroscopic detection of the secondaries of the Hyades interferometric spectroscopic binary theta(sup 2) Tauri and of the interferometric spectroscopic binary alpha Andromedae

We report new high-resolution, wide-wavelength-coverage CCD observations of the visual and near-infrared spectra of the interferometric spectroscopic binaries theta(sup 2) Tau (primary spectral type A 7 III) and alpha And (primary spectral type B8 IVpMnHg), which allow the first direct spectroscopic detection of their secondaries. We have measured primary and secondary radial velocities and used them to redetermine the spectroscopic orbits of the primaries, make an improved determination of K(sub 2) for theta(sup 2) Tau, and measure K(sub 2) for alpha And for the first time. The spectroscopic orbits combined with the interferometrically measured visual orbits of theta(sup 2) Tau and alpha And provide masses and distances, M(sub 1) = 2.1 +/- 0.3 solar mass, M(sub 2) = 1.6 +/- 0.2 solar mass, and d = 44.1 +/- 2.2 pc for theta(sup 2) Tau and M(sub 1) = 5.5 +/- 0.5 solar mass, M(sub 2) = 2.3 +/- 0.2 solar mass, and d = 34.0 +/- 1.3 pc for alpha And. The distance to theta(sup 2) Tau and a foreground correction of 0.07 +/- 0.05 mag set the distance to the center of the Hyades cluster at 45.5 +/- 2.5 pc, or m - M = 3.29 +/- 0.12. Indirect estimates of the mass of theta(sup 2) Tau's primary, made via the mass-luminosity relation and via the Hyades cluster turnoff mass, are consistent with these dynamical masses for its primary and secondary. But in the case of alpha And, the mass-luminosity relation suggests that our dynamical masses for its primary and secondary may be too large. For alpha And somewhat smaller dynamical masses (4.0 and 1.9 solar mass) and the correspondingly smaller distance (31 pc), required by the corresponding larger orbital parallax, provide results consistent with the mass-luminosity relation for normal stars.

Tomkin, Jocelyn↗