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NASA NTRS1984

Evaluation of dissociated and steam-reformed methanol as automotive engine fuels

Dissociated and steam reformed methanol were evaluated as automotive engine fuels. Advantages and disadvantages in using methanol in the reformed rather than liquid state were discussed. Engine dynamometer tests were conducted with a four cylinder, 2.3 liter, spark ignition automotive engine to determine performance and emission characteristics operating on simulated dissociated and steam reformed methanol (2H2 + CO and 3H2 + CO2 respectively), and liquid methanol. Results are presented for engine performance and emissions as functions of equivalence ratio, at various throttle settings and engine speeds. Operation on dissociated and steam reformed methanol was characterized by flashback (violent propagation of a flame into the intake manifold) which limited operation to lower power output than was obtainable using liquid methanol. It was concluded that: an automobile could not be operated solely on dissociated or steam reformed methanol over the entire required power range - a supplementary fuel system or power source would be necessary to attain higher powers; the use of reformed mechanol, compared to liquid methanol, may result in a small improvement in thermal efficiency in the low power range; dissociated methanol is a better fuel than steam reformed methanol for use in a spark ignition engine; and use of dissociated or steam reformed methanol may result in lower exhaust emissions compared to liquid methanol.

Lalk, T. R.↗

NASA NTRS1977

Comparison of rigorous and simple vibrational models for the CO2 gasdynamic laser

The accuracy of a simple vibrational model for computing the gain in a CO2 gasdynamic laser is assessed by comparing results computed from it with results computed from a rigorous vibrational model. The simple model is that of Anderson et al. (1971), in which the vibrational kinetics are modeled by grouping the nonequilibrium vibrational degrees of freedom into two modes, to each of which there corresponds an equation describing vibrational relaxation. The two models agree fairly well in the computed gain at low temperatures, but the simple model predicts too high a gain at the higher temperatures of current interest. The sources of error contributing to the overestimation given by the simple model are determined by examining the simplified relaxation equations.

Monson, D. J.↗

NASA NTRS1998

Analysis of Physical Properties of Dust Suspended in the Mars Atmosphere

Methods for iteratively determining the infrared optical constants for dust suspended in the Mars atmosphere are described. High quality spectra for wavenumbers from 200 to 2000 1/cm were obtained over a wide range of view angles by the Mariner 9 spacecraft, when it observed a global Martian dust storm in 1971-2. In this research, theoretical spectra of the emergent intensity from Martian dust clouds are generated using a 2-stream source-function radiative transfer code. The code computes the radiation field in a plane-parallel, vertically homogeneous, multiply scattering atmosphere. Calculated intensity spectra are compared with the actual spacecraft data to iteratively retrieve the optical properties and opacity of the dust, as well as the surface temperature of Mars at the time and location of each measurement. Many different particle size distributions a-re investigated to determine the best fit to the data. The particles are assumed spherical and the temperature profile was obtained from the CO2 band shape. Given a reasonable initial guess for the indices of refraction, the searches converge in a well-behaved fashion, producing a fit with error of less than 1.2 K (rms) to the observed brightness spectra. The particle size distribution corresponding to the best fit was a lognormal distribution with a mean particle radius, r(sub m) 0.66 pm, and variance, omega(sup 2) = 0.412 (r(sub eff) = 1.85 microns, v(sub eff) =.51), in close agreement with the size distribution found to be the best fit in the visible wavelengths in recent studies. The optical properties and the associated single scattering properties are shown to be a significant improvement over those used in existing models by demonstrating the effects of the new properties both on heating rates of the Mars atmosphere and in example spectral retrieval of surface characteristics from emission spectra.

Snook, Kelly↗

NASA NTRS2002

Ion Storage with the High Performance Antiproton Trap (HiPAT)

The matter antimatter reaction represents the densest form of energy storage/release known to modern physics: as such it offers one of the most compact sources of power for future deep space exploration. To take the first steps along this path, NASA-Marshall Space Flight Center is developing a storage system referred to as the High Performance Antiproton Trap (HiPAT) with a goal of maintaining 10(exp 12) particles for up to 18 days. Experiments have been performed with this hardware using normal matter (positive hydrogen ions) to assess the device's ability to hold charged particles. These ions are currently created using an electron gun method to ionize background gas; however, this technique is limited by the quantity that can be captured. To circumvent this issue, an ion source is currently being commissioned which will greatly increase the number of ions captured and more closely simulate actual operations expected at an antiproton production facility. Ions have been produced, stored for various time intervals, and then extracted against detectors to measure species, quantity and energy. Radio frequency stabilization has been tested as a method to prolong ion lifetime: results show an increase in the baseline 1/e lifetime of trapped particles from hours to days. Impurities in the residual background gas (typically carbon-containing species CH4, CO, CO2, etc.) present a continuing problem by reducing the trapped hydrogen population through the mechanism of ion charge exchange.

Martin, James↗

NASA NTRS1986

Studies of the ultraviolet spectra of astronomical sources

An intensive program of observations of the Comet Halley during the week of the Vega 2 and Giotto encounters was carried out by the International Ultraviolet Explorer (IUE) satellite observatory. The IUE Fine Error Sensor, normally used for target acquisition and tracking, was used in a photometer mode to provide nealy continuous light curves over an 8 hour observing shift, a unique capability relative to ground-bases observers. The ultraviolet data can be used to derive an estimate of the total gas production rate even though the models generally used for this purpose assume a steady-state gas production which is clearly not the case for Halley. Additionally, the IUE data provide column abundances of carbon, oxygen, sulfur, OH, CO, CS, C2, and CO2 to compare with the in-situ measurements of these species by Vega 2 and Giotto.

Source record↗

DOE OSTI2023

Shooter Alarm System Final Report FY23

Lawrence Livermore National Laboratory (LLNL) is developing a multiphysics sensor package for automatic live arms fire detection for use in schools, houses of worship, hospi tals, etc. The goal is to have a package the size of a common smoke or CO2 detector with a price point of $50 or less which may be deployed throughout the aforementioned facilities. The commercial device will detect live gun fire with low probability of false alarm and auto matically alert first responders. A prototype board with four accelerometers, two infrared (IR) and two microphones has been developed and deployed at two experiments at LLNL’s Small Firearms Training Facility (SFTF). The device successfully and consistently measured signals on the accelerometer and acoustic channels. IR responses were measured depending upon the environment and sound source.

42 ENGINEERING↗

NASA NTRS1977

Quantitative remote measurements of pollutants from stationary sources using Raman lidar

The several advantages of Raman lidar for remote measurements of stationary source emissions were quantitatively evaluated using a calibration tank at a distance of 300 m at night. Measurements of approximately 10 to the 3rd ppm SO2 with a 12% accuracy were demonstrated in an observation time of 15 min using a 1.5-J ruby laser at 30 pulses/min, 6-m range resolution, interference filters, photon counting detection, and a 20-cm receiver. Measurement accuracy was checked by measuring known concentrations of SO2 in the tank, by tuning the interference filters through the SO2 Raman line, and by varying the CO2 concentration to very high levels during the SO2 measurements. Evaluation of the seriousness of induced fluorescence from plume aerosols failed due to the inability to simulate the plume aerosols.

Poultney, S. K.↗

DOE OSTI2020

Mobilization of trace metals from caprock and formation rocks at the Illinois Basin – Decatur Project demonstration site under geological carbon dioxide sequestration conditions

One concern for geologic CO 2 sequestration is the potential leakage of CO 2 or CO 2 -saturated brine containing trace metals into overlying aquifers, which poses the risk of adversely affecting underground sources of drinking water. In this work, rock and brine samples collected in the Illinois Basin – Decatur Project (IBDP), a large-scale geological CO 2 sequestration demonstration project in Decatur, Illinois, USA, as well as synthetic brine samples were used to understand the mobilization of trace metals as a result of CO 2 –rock–brine interactions under IBDP-specific conditions (50 °C and 20.6 MPa). Rock sample characterization indicated that, at the IBDP site, trace metal concentrations were greatest in cap rock samples from the Eau Claire Formation, compared with those from formations above and below this Formation. The natural brine samples collected from the Mt. Simon Sandstone reservoir were highly reducing and saline, with trace metal concentrations up to 680 times greater than the U.S. Environmental Protection Agency-prescribed drinking water standards. Batch leaching experiments indicated that both trace metal mobilization from rock and immobilization from the brine occurred when high-pressure CO 2 was introduced into the rock-brine system. The amounts of metals mobilized from the rock generally accounted for <5% of the total metals in the rock, but for some metals, including Ni, Pb, and Tl, up to 63% of the metals in the rock were mobilized to the brine. Leaching of trace metals into synthetic brines was different from that into the natural brine. The results of this study provided current information on the trace element sources and will help in risk simulations and experimental design to further evaluate potential impact of leakage on groundwater quality, which is important for future GCS projects to consider for monitoring and containment assurance purposes.

58 GEOSCIENCES↗

NASA NTRS1999

A Study of Mars Dust Environment Simulation at NASA Johnson Space Center Energy Systems Test Area Resource Conversion Test Facility

The dust environment on Mars is planned to be simulated in a 20 foot thermal-vacuum chamber at the Johnson Space Center, Energy Systems Test Area Resource Conversion Test Facility in Houston, Texas. This vacuum chamber will be used to perform tests and study the interactions between the dust in Martian air and ISPP hardware. This project is to research, theorize, quantify, and document the Mars dust/wind environment needed for the 20 foot simulation chamber. This simulation work is to support the safety, endurance, and cost reduction of the hardware for the future missions. The Martian dust environment conditions is discussed. Two issues of Martian dust, (1) Dust Contamination related hazards, and (2) Dust Charging caused electrical hazards, are of our interest. The different methods of dust particles measurement are given. The design trade off and feasibility were studied. A glass bell jar system is used to evaluate various concepts for the Mars dust/wind environment simulation. It was observed that the external dust source injection is the best method to introduce the dust into the simulation system. The dust concentration of 30 Mg/M3 should be employed for preparing for the worst possible Martian atmosphere condition in the future. Two approaches thermal-panel shroud for the hardware conditioning are discussed. It is suggested the wind tunnel approach be used to study the dust charging characteristics then to be apply to the close-system cyclone approach. For the operation cost reduction purpose, a dehumidified ambient air could be used to replace the expensive CO2 mixture for some tests.

Chen, Yuan-Liang Albert↗

NASA NTRS2009

Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed yttria-stabilized zirconia coatings on turbine-engine components. Progression of TBC delamination occurs by the formation of buried cracks that grow and then link together to produce eventual TBC spallation. The mid-infrared reflectance imaging system described here makes it possible to see delamination progression that is invisible to the unaided eye, and therefore give sufficiently advanced warning before delamination progression adversely affects engine performance and safety. The apparatus (see figure) includes a commercial mid-infrared camera that contains a liquid-nitrogen-cooled focal plane indium antimonide photodetector array, and imaging is restricted by a narrow bandpass centered at wavelength of 4 microns. This narrow wavelength range centered at 4 microns was chosen because (1) it enables avoidance of interfering absorptions by atmospheric OH and CO2 at 3 and 4.25 microns, respectively; and (2) the coating material exhibits maximum transparency in this wavelength range. Delamination contrast is produced in the midinfrared reflectance images because the introduction of cracks into the TBC creates an internal TBC/air-gap interface with a high diffuse reflectivity of 0.81, resulting in substantially higher reflectance of mid-infrared radiation in regions that contain buried delamination cracks. The camera is positioned a short distance (.12 cm) from the specimen. The mid-infrared illumination is generated by a 50-watt silicon carbide source positioned to the side of the mid-infrared camera, and the illumination is collimated and reflected onto the specimen by a 6.35-cm-diameter off-axis paraboloidal mirror. Because the collected images are of a steady-state reflected intensity (in contrast to the transient thermal response observed in infrared thermography), collection times can be lengthened to whatever extent needed to achieve desired signal-to-noise ratios. Each image is digitized, and the resulting data are processed in several steps to obtain a true mid-infrared reflectance image. The raw image includes thermal radiation emitted by the specimen in addition to the desired reflected radiation. The thermal-radiation contribution is eliminated by subtracting the image obtained with the illumination off from the image obtained with the illumination on. A flat-field correction is then made to remove the effects of non-uniformities in the illumination level and pixel-to-pixel variations in sensitivity. This correction is performed by normalizing to an image of a standard object that has a known reflectance at a wavelength of 4 microns. After correction, each pixel value is proportional to the reflectance (at a wavelength of 4-microns) at the corresponding location on the specimen. Mid-infrared reflectance imaging of specimens that were thermally cyc led for different numbers of cycles was performed and demonstrated t hat mid-infrared reflectance imaging was able to monitor the gradual delamination progression that occurs with continued thermal cycling . Reproducible values were obtained for the reflectance associated w ith an attached and fully delaminated TBC, so that intermediate refle ctance values could be interpreted to successfully predict the numbe r of thermal cycles to failure.

Edlridge, Jeffrey I.↗

NASA NTRS1993

Atmospheric sulfur hexafluoride - Sources, sinks and greenhouse warming

An estimate is obtained of worldwide production of SF6, from which a global emission rate is derived and extrapolated for the next 20 years. The atmospheric lifetime of SF6 is then estimated based on a known mechanism (e.g., photolysis and atmospheric oxidation) and/or on the mass balance method. Finally, the radiative forcing of SF6 is calculated based on recent laboratory IR absorption data, and the expected warming over the time period 1950-2010 is computed for several emission scenarios. Calculations showed that SF6 is 3 times more effective as a greenhouse gas compared to CFC 11 on a per-molecule basis. However, based on projected emission scenarios, the expected warming from SF6 through 2010 is small (0.004 C), compared to the warming from CO2 and other trace gases (0.8 C).

Ko, Malcolm K. W.↗

NASA NTRS2017

Mars Molniya Orbit Atmospheric Resource Mining

This NASA Innovative Advanced Concepts (NIAC) Phase I study examined the revolutionary concept of performing resource collection and utilization during Mars orbital operations in order to enable the landing of large payloads. An exploration architecture was developed, out of which several mission alternatives were developed. Concepts of operations were then developed for each mission alternative, followed by concepts for spacecraft systems, which were traded to assess their feasibility. A novel architecture using Mars Molniya Orbit Atmospheric Resource Mining is feasible to enable an Earth-independent and pioneering, permanent human presence on Mars by providing a reusable, single-stage-to-orbit transportation system. This will allow cargo and crew to be routinely delivered to and from Mars without transporting propellants from Earth.In Phase I, our study explored how electrical energy could be harnessed from the kinetic energy of the incoming spacecraft and then be used to produce the oxygen necessary for landing. This concept of operations is revolutionary in that its focus is on using in situ resources in complementary and varied forms: the upper atmosphere of Mars is used for aerocapture, which is followed by aerobraking, the kinetic energy of the spacecraft is transformed into usable electrical energy during aerobraking, and the atmospheric composition is the source of oxidizer for a landing under supersonic retropropulsion. This NASA Innovative Advanced Concepts (NIAC) Phase I study explores a novel mission architecture to establish routine, Earth-independent transfer of large mass payloads between Earth and the Mars surface and back to Mars orbit. The first stage of routine mission operations involves an atmospheric resource mining aerobraking campaign following aerocapture into a highly elliptical Mars orbit. During each pass through the atmosphere, the vehicle ingests the atmospheric oxidizer and stores it onboard, using solid oxide electrolysis to convert the primarily CO2 atmosphere into usable O2 for propellant. Power is made available through the use of magnetohydrodynamic energy generation, which converts the motion of the plasma in the shock later into usable electrical energy. Upon termination of the aerobraking sequence, the descent vehicle detaches from the orbit stack, deorbits, and executes the entry, descent, and landing sequence. Hypersonic deceleration is achieved via a deployable heat shield to lower the vehicle ballistic coefficient, and supersonic and subsonic deceleration are achieved via retropropulsion. Mars surface operations involve resource mining of the Martian regolith to produce CH4 and O2 propellant to be used for the subsequent MDAV ascent back to high Mars orbit (HMO) providing an apoapsis raise maneuver to initialize the aerobraking sequence, in addition to providing fuel from the Mars surface for EDL propulsive descent. The Resource Collector Vehicle (RCV), which is used for the orbital mining operations, is raised back to HMO via onboard deployable augmented solar electric propulsion. Concepts of operations were developed for each mission alternative, to evaluate between them and assess feasibility.

Mining↗

NASA NTRS2017

Satellites May Underestimate Rice Residue and Associated Burning Emissions in Vietnam

In this study, we estimate rice residue, associated burning emissions, and compare results with existing emissions inventories employing a bottom-up approach. We first estimated field-level post-harvest rice residues, including separate fuel-loading factors for rice straw and rice stubble. Results suggested fuel-loading factors of 0.27 kg/sq m (+/-0.033), 0.61 kg/sq m (+/-0.076), and 0.88 kg/sq m (+/-0.083) for rice straw, stubble, and total post-harvest biomass, respectively. Using these factors, we quantified potential emissions from rice residue burning and compared our estimates with other studies. Our results suggest total rice residue burning emissions as 2.24 Gg PM2.5, 36.54 Gg CO and 567.79 Gg CO2 for Hanoi Province, which are significantly higher than earlier studies. We attribute our higher emission estimates to improved fuel-loading factors; moreover, we infer that some earlier studies relying on residue-to-product ratios could be underestimating rice residue emissions by more than a factor of 2.3 for Hanoi, Vietnam. Using the rice planted area data from the Vietnamese government, and combining our fuel-loading factors, we also estimated rice residue PM2.5 emissions for the entirety of Vietnam and compared these estimates with an existing all-sources emissions inventory, and the Global Fire Emissions Database (GFED). Results suggest 75.98 Gg of PM2.5 released from rice residue burning accounting for 12.8% of total emissions for Vietnam. The GFED database suggests 42.56 Gg PM2.5 from biomass burning with 5.62 Gg attributed to agricultural waste burning indicating satellite-based methods may be significantly underestimating emissions. Our results not only provide improved residue and emission estimates, but also highlight the need for emissions mitigation from rice residue burning.

Air pollution↗

DOE OSTI2023

Techno-economic evaluation of industrial heat pump applications in US pulp and paper, textile, and automotive industries

Industrial process heat decarbonization through electrification could contribute significantly to climate change mitigation efforts. In the US industry, thermal processes accounted for more than two-thirds of the total final energy demand in 2021. Cross-cutting electrification technologies like industrial heat pumps are suitable for the process heat supply to several industrial unit operations in a sustainable way while also improving overall energy efficiency. This study employs a bottom-up approach to investigate the techno-enviro-economic potentials of deploying high-temperature and steam-generating heat pumps in US textile, pulp and paper, and automotive sectors in different timeframes. The results show that the annual technical potential energy and CO 2 savings by electrifying heat supply are 310 PJ (or 36% of the projected energy demand) and 28 MtCO 2 (or 71% of the projected CO 2 emissions) in 2050 respectively, however, these incur additional costs in each sector (ranging between 5 and 18 $\$$/GJ). The required heating capacity of industrial heat pumps is estimated at 15 GW, which translates roughly into a market of over 6000 heat pump units and an investment volume of $\$$7 billion in the studied processes. Although there may be individual cost-effective opportunities for electrifying heat supply in specific industrial sites, the overall costs are estimated to be high in the three industrial sectors due to the large disparity between electricity and natural gas prices and low heat source temperatures. To overcome the identified techno-economic barriers, comprehensive action plans for different stakeholders are also given. This study provides novel insights that should inform policymakers’ and executives’ decisions about the electrification of the current and future US industrial heat supply in relevant industrial sectors.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS2001

Observations of Circumstellar Material Around Evolved Stars With the ISI

The U.C. Berkeley Infrared Spatial Interferometer (ISI) is a stellar interferometer operating in the 9-12 micron region and has been in operation from 1988 until the present. It utilizes heterodyne detection using CO2 laser local oscillators and currently includes two 1.65 m movable telescopes mounted in semi-trailers and baselines up to about 65 m in length. A third telescope is being integrated with the other two and within the next year will operate as an imaging interferometer providing data with three simultaneous baselines and a closure phase, and baselines up to about 75 m. During the past twelve years the ISI has been used extensively for studies of circumstellar material around evolved stars. Multi-epoch observations of a sample of prototypical sources have elucidated the location and time scales for dust formation around these stars. These time scales can be as short as approx.10 years for Mira stars and as long as approx. 100 years for supergiants. For stars like Mira itself there is evidence for departure from spherical symmetry and episodes of dust formation and destruction. For some stars motion of dust has been observed -- IK Tau is one example, and NML Cyg is another. The molecules Silane and Ammonia were observed for the extreme carbon star IRC +10216 and the supergiant VY CMa pinpointing their location relative to the inner radius of the dust shell. Somewhat surprisingly, these molecules were found to form many stellar radii away from the inner radius of the dust shell, implying that they form by interactions with the surfaces of dust grains. Last year observations with the longest baselines lead to new precision diameters of $o$ Ceti and $\alpha$ Orionis, and are continuing on a somewhat larger set of Mira variable and supergiant stars.

Danchi, W. C.↗

NASA NTRS1985

Photochemical consequences of enhanced CO2 levels in earth's early atmosphere

Greatly enhanced atmospheric CO2 concentrations are the most likely mechanism for offsetting the effects of reduced solar luminosity early in the earth's history. CO2 levels of 80 to 600 times the present value could have maintained a mean surface temperature of 0 C to 15 C, given a 25 percent decrease in solar output. Such high CO2 levels are at least qualitatively consistent with the present understanding of the carbonate-silicate geochemical cycle. The presence of large amounts of CO2 has important implications for the composition of the earth's prebiotic atmosphere. The hydrogen budget of a high-CO2 primitive atmosphere would have been strongly influenced by rainout of H2O2 and H2CO. The reaction of H2O2 with dissolved ferrous iron in the early oceans could have been a major sink for atmospheric oxygen. The requirement that this loss of oxygen be balanced by a corresponding loss of hydrogen (by escape to space and rainout of H2CO) implies that the atmospheric H2 mixing ratio was greater than 2 x 10 to the -5th and the ground level O2 mixing ratio was below 10 to the -12th, even if other surface sources of H2 were small. These results are only weakly dependent on changes in solar UV flux, rainout rates, and vertical mixing rates in the primitive atmosphere.

Kasting, J. F.↗

NASA NTRS1989

A space-based combined thermophotovoltaic electric generator and gas laser solar energy conversion system

This paper describes a spaceborne energy conversion system consisting of a thermophotovoltaic electric generator and a gas laser. As a power source for the converson, the system utilizes an intermediate blackbody cavity heated to a temperature of 2000-2400 K by concentrated solar radiation. A double-layer solar cell of GaAs and Si forms a cylindrical surface concentric to this blackbody cavity, receiving the blackbody radiation and converting it into electricity with cell conversion efficiency of 50 percent or more. If the blackbody cavity encloses a laser medium, the blackbody radiation can also be used to simultaneously pump a lasing gas. The feasibility of blackbody optical pumping at 4.3 microns in a CO2-He gas mixture was experimentally demonstrated.

Yesil, Oktay↗

NASA NTRS2003

Therma1 Conductivity and Durability of Advanced Thermal Barrier Coatings

Thermal barrier coatings (TBCs) will play a crucial role in advanced gas turbine engines because of their ability to further increase engine operating temperature and reduce cooling, thus helping to achieve engine emission and efficiency goals. Future TBCs must be designed with increased phase stability, lower thermal conductivity, and improved sintering and thermal stress resistance in order to effectively protect engine hot-section components. Advanced low conductivity TBCs are being developed at NASA by incorporating multi-component oxide dopants into zirconia-yttria or hafnia-yttria to promote the formation of thermodynamically stable defect clusters within the coating structures. This presentation will primarily focus on thermal conductivity and durability of the novel defect cluster thermal barrier coatings for turbine airfoil and combustor applications, determined by a unique CO2 laser heat-flux approach. The laser heat-flux testing approach emphasizes the real-time monitoring and assessment of the coating thermal conductivity under simulated engine temperature and thermal gradient conditions. The conductivity increase due to coating sintering (and/or phase change) and the conductivity decrease due to coating delamination have been determined under steady-state, cyclic, uniform or non-uniform heat-flux conditions. The coating radiation flux resistance has been evaluated by varying coating thermal gradients, and also by using a laser-heated radiative-flux source. Advanced multi-component TBC systems have been shown to have significantly reduced thermal conductivity and improved high temperature stability due to the nano-sized, low mobility defect clusters associated with the paired rare earth dopant additions. The effect of oxide defect cluster dopants on coating thermal conductivity, thermal stability and furnace cyclic durability will also be discussed. The current low conductivity TBC systems have demonstrated long-term cyclic durability at very high temperatures which is far beyond the baseline ZrO2-Y2O3 capabilities.

Zhu, Dong-Ming↗