Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “TeAs”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Chitosan Coating Functionalized with Flaxseed Oil and Green Tea Extract as a Bio-Based Solution for Beef Preservation

Ecological and safe packaging solutions arise as pivotal points in the development of an integrated system for sustainable meat production. The aim of this study was to assess the effect of a combined chitosan (Ch) + green tea extract (GTE) + essential oil (thyme oil, TO; flaxseed oil, FO; or oregano oil, OO) coating on the safety and quality of vacuum-packaged beef during storage at 4 °C. An optimized bio-based coating formulation was selected (2% Ch + 2% GTE + 0.1% FO) to be applied to three fresh beef cuts (shoulder, Sh; knuckle, Kn; Striploin, St) based on its pH (5.8 ± 0.1), contact angle (22.3 ± 0.4°) and rheological parameters (viscosity = 0.05 Pa.s at shear rate > 20 s−1). Shelf-life analysis showed that the Ch–GTE–FO coating delayed lipid oxidation and reduced total viable counts (TVC) and Enterobacteriaceae growth compared with uncoated beef samples over five days. In addition, Ch–GTE–FO coating decreased total color changes of beef samples (e.g., ∆E* = 9.84 and 3.94, for non-coated and coated Kn samples, respectively) for up to five days. The original textural parameters (hardness, adhesiveness and springiness) of beef cuts were maintained during storage when Ch–GTE–FO coating was applied. Based on the physicochemical and microbial characterization results, the combination of the Ch–GTE–FO coating developed was effective in preserving the quality of fresh beef cuts during refrigerated storage along with vacuum packaging.

Mendes, Cíntia G.↗
NASA NTRS1983

Pulse evolution and mode selection characteristics in a TEA-CO2 laser perturbed by injection of external radiation

A grating-tunable TEA-CO2 laser with an unstable resonator cavity, modified to allow injection of CW CO2 laser radiation at the resonant transition line by means of an intracavity NaCl window, has been used to study the coupling requirements for generation of single frequency pulses. The width and shape of the mode selection region, and the dependence of the gain-switched spike buildup time and the pulse shapes on the intensity and detuning frequency of the injected radiation are reported. Comparisons of the experimental results with previously reported mode selection behavior are discussed.

Flamant, P. H.↗
NASA NTRS1986

Flight tests of a range-resolved airborne dial with two min-tea CO2 lasers

It is important to measure regional distributions of ozone concentrations in a short time for understanding a mechanism of photo-chemical smog development. An airborne Differential Absorption Lidar (DIAL) system with two low-power mini-TEA CO2 lasers was developed for measuring three-dimensional distributions of ozone in the lower troposphere. The CO2 DIAL is a nadir-looking system and is designed to measure ozone profiles between ground and airplane by using atmospheric aerosols as a distributed radar target. First flight test with a single laser were conducted in February 1985 over the Tokyo area. The system was operated at an altitude of 5000 ft. Results of the first flight tests show that the height profiles of the received power in the boundary layer were different between over land and ocean. The received power has to be inverted to an expression of a single optical parameter to see real aerosol distributions. Inversion of the lidar signal to the aerosol extinction was performed by using Klett's solution.

Itabe, T.↗
NASA NTRS1987

Review of the frequency stabilization of TEA CO2 laser oscillators

Most applications of TEA CO2 lasers in heterodyne radar systems require that the transmitter has a high degree of frequency stability. This ensures good Doppler resolution and maximizes receiver sensitivity. However, the environment within the device is far from benign with fast acoustic and electrical transients being present. Consequently the phenomena which govern the frequency stability of pulsed lasers are quite different from those operative in their CW counterparts. This review concentrates on the mechanisms of chirping within the output pulse; pulse to pulse frequency drift may be eliminated by frequency measurement and correction on successive pulses. It emerges that good stability hinges on correct cavity design. The energy-dependent laser-induced frequency sweep falls dramatically as mode diameter is increased. Thus, it is necessary to construct resonators with good selectivity for single mode operation while having a large spot size.

Willetts, David V.↗
NASA NTRS1987

Frequency stabilization and transverse mode discrimination in injection-seeded unstable resonator TEA CO2 lasers

Longitudinal mode selection by injection has been demonstrated as a viable technique for TEA-CO2 lasers with pulse energies of a Joule or greater. Once reliable generation of single-longitudinal-mode (SLM) pulses is obtained, the characteristics and the causes of intrapulse frequency variation can be studied. These include the effect of the decaying plasma, the thermal gradient due to the energy dissipation associated with the laser mechanism itself, and the pressure shift of the center frequency of the laser transition. The use of the positive-branch unstable resonator as an efficient means of coupling a discharge with large spatial dimensions to an optical cavity mode introduces another concern: namely, what can be done to emphasize transverse mode discrimination in an unstable resonator cavity while maintaining high coupling efficiency. These issues are discussed in this paper, and relevant experimental results are included.

Ancellet, G. M.↗
NASA NTRS1992

Effects of various cavity designs on the performance of a CO2 TEA laser with an unstable resonator

Unstable resonator modeling has been carried out for an injection-seeded CO2 transversely excited atmosphere (TEA) laser in the NOAA/ERL/Wave Propagation Laboratory (WPL) Doppler lidar to examine the effects of various cavity designs on the quality of the output beam. The results show the effects of an injection pinhole, electrode spacing, mirror tilt, and radial reflectivity function of the output coupler. The electrode spacing in this laser has negligible effect. The injection pinhole, however, produces complicated structures in the output patterns. If the pinhole is removed, the output pattern is much smoother, and the frequency jitter is smaller. Misalignment sensitivity is very closely related to the radial reflectivity function. The superparabolic function provides the highest coupling efficiency, largest beam size, and good collimation, but produces a slightly higher misalignment sensitivity compared with a parabolic function. The Gaussian function provides the lowest misalignment sensitivity, but it produces the smallest beam size and the largest beam divergence. Also, the coupling coefficient is 50 percent lower than the optimum value. Methods for using a flat diffraction grating in unstable resonators are also investigated. The best way is to use a flat grating/positive lens combination to replace the back concave mirror.

Zhao, Yanzeng↗
NASA NTRS1993

Transient Ejector Analysis (TEA) code user's guide

A FORTRAN computer program for the semi analytic prediction of unsteady thrust augmenting ejector performance has been developed, based on a theoretical analysis for ejectors. That analysis blends classic self-similar turbulent jet descriptions with control-volume mixing region elements. Division of the ejector into an inlet, diffuser, and mixing region allowed flexibility in the modeling of the physics for each region. In particular, the inlet and diffuser analyses are simplified by a quasi-steady-analysis, justified by the assumption that pressure is the forcing function in those regions. Only the mixing region is assumed to be dominated by viscous effects. The present work provides an overview of the code structure, a description of the required input and output data file formats, and the results for a test case. Since there are limitations to the code for applications outside the bounds of the test case, the user should consider TEA as a research code (not as a production code), designed specifically as an implementation of the proposed ejector theory. Program error flags are discussed, and some diagnostic routines are presented.

Drummond, Colin K.↗
DOE OSTI2020

Materials Data on TeAs by Materials Project

AsTe is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. As2+ is bonded to six equivalent Te2- atoms to form a mixture of corner and edge-sharing AsTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. All As–Te bond lengths are 2.97 Å. Te2- is bonded to six equivalent As2+ atoms to form a mixture of corner and edge-sharing TeAs6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeAs(ClF2)3 by Materials Project

AsTe(ClF2)3 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two AsTe(ClF2)3 ribbons oriented in the (0, 0, 1) direction. As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.75–1.82 Å. Te4+ is bonded in a 5-coordinate geometry to three Cl1- and two F1- atoms. There are a spread of Te–Cl bond distances ranging from 2.30–2.32 Å. There are one shorter (2.70 Å) and one longer (2.72 Å) Te–F bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Te4+ atom. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Te4+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to one As5+ and one Te4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to one As5+ and one Te4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeAs(BrF2)3 by Materials Project

AsTe(BrF2)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. As5+ is bonded to six F1- atoms to form AsF6 octahedra that share corners with three equivalent TeBr3F3 octahedra. The corner-sharing octahedra tilt angles range from 35–54°. There are a spread of As–F bond distances ranging from 1.76–1.80 Å. Te4+ is bonded to three Br1- and three F1- atoms to form distorted TeBr3F3 octahedra that share corners with three equivalent AsF6 octahedra. The corner-sharing octahedra tilt angles range from 35–54°. There are one shorter (2.47 Å) and two longer (2.48 Å) Te–Br bond lengths. There are a spread of Te–F bond distances ranging from 2.77–2.98 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted single-bond geometry to one Te4+ atom. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to one Te4+ and one F1- atom. The Br–F bond length is 3.12 Å. In the third Br1- site, Br1- is bonded in a 1-coordinate geometry to one Te4+ and one F1- atom. The Br–F bond length is 3.14 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Br1- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Br1- atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to one As5+ and one Te4+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one As5+ and one Te4+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Te4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeAs(SeF3)2 by Materials Project

AsTe2Se4F9AsF3 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is two-dimensional and consists of four trifluoroarsine molecules and two AsTe2Se4F9 sheets oriented in the (0, 0, 1) direction. In each AsTe2Se4F9 sheet, As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.74–1.83 Å. There are two inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 2-coordinate geometry to one Se+1.50- and two F1- atoms. The Te–Se bond length is 2.65 Å. There are one shorter (1.97 Å) and one longer (2.54 Å) Te–F bond lengths. In the second Te4+ site, Te4+ is bonded in a distorted single-bond geometry to one Se+1.50- and one F1- atom. The Te–Se bond length is 2.76 Å. The Te–F bond length is 2.07 Å. There are four inequivalent Se+1.50- sites. In the first Se+1.50- site, Se+1.50- is bonded in a 1-coordinate geometry to one Se+1.50- and one F1- atom. The Se–Se bond length is 2.41 Å. The Se–F bond length is 2.87 Å. In the second Se+1.50- site, Se+1.50- is bonded in a 5-coordinate geometry to one Te4+, two Se+1.50-, and two F1- atoms. The Se–Se bond length is 2.45 Å. There are one shorter (2.89 Å) and one longer (3.21 Å) Se–F bond lengths. In the third Se+1.50- site, Se+1.50- is bonded in a 2-coordinate geometry to one Te4+ and one F1- atom. The Se–F bond length is 3.12 Å. In the fourth Se+1.50- site, Se+1.50- is bonded in a 2-coordinate geometry to one Se+1.50- and two F1- atoms. There are one shorter (1.80 Å) and one longer (2.47 Å) Se–F bond lengths. There are nine inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Te4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ and one Se+1.50- atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Te4+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to one As5+ and one Se+1.50- atom. In the sixth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one As5+ and one Se+1.50- atom. In the seventh F1- site, F1- is bonded in a 1-coordinate geometry to one As5+, one Te4+, and one Se+1.50- atom. In the eighth F1- site, F1- is bonded in a single-bond geometry to two Se+1.50- atoms. In the ninth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Conceptual Basis and Techno-Economic Modeling for Integrated Algal Biorefinery Conversion of Microalgae to Fuels and Products (2019 NREL TEA Update: Highlighting Paths to Future Cost Goals via a New Pathway for Combined Algal Processing)

The report documents the conceptual basis for a new potential Combined Algal Processing design strategy which may allow more flexibility in accommodating different algal biomass feedstock compositions, by enabling upgrading of both protein and carbohydrates in a single step, without a strict requirement for either component to be in soluble or monomeric form, while maintaining effective wet lipid extraction techniques to enable high lipid recoveries. In light of previously-established constraints around algal biomass costs (which are significantly higher than lignocellulosic terrestrial biomass), the present CAP processing strategy reflects an integrated biorefinery concept producing both fuels and value-added chemical coproducts as a means to improve profitability and generate coproduct revenues to help drive down the minimum fuel selling price (MFSP) towards economically viable levels. Namely, this report highlights an integrated CAP biorefinery process and associated technical targets that would be required to achieve U.S. Department of Energy target MFSP goals of $2.5/gallon gasoline equivalent by 2030. This is accomplished by a process involving low-cost seasonal storage of algal biomass during high-growth seasons, rapid flash hydrolysis pretreatment of the biomass, solvent extraction of pretreated biomass, cleanup and fractionation of lipids into triglyceride and free fatty acid fractions, and a series of thermochemical conversion steps to upgrade carbohydrates and protein to hydrocarbon fuels. These steps include mild oxidative treatment (MOT), a process originally investigated at NREL for upgrading lignin, followed by catalytic ketonization and hydrotreating of MOT products to fuels. Isolated triglycerides are sent to a coproduct train, with the base case focused on upgrading to polyurethane foams as a high-value, high-market-volume coproduct.

09 BIOMASS FUELS↗