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Results for “Measuring Methods”

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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Nozzle extraction process and handlemeter for measuring handle

Method and apparatus for quantitatively measuring the handle of fabrics and other flexible materials is presented. Handle is that term used to refer to the qualities of drapability, flexibility, compressibility, foldability, stretchability, pliability, etc., possessed by fabrics and other flexible materials. In the present invention the handle of a material sample is quantified by measuring the force required to draw the sample through an orifice and expressing the resultant extractive force as a function of test apparatus geometry and the amount of sample drawn through the orifice to arrive at quantitative measure of handle, to be defined as handle modulus, for the sample in question.

Alley, V. L., Jr.↗
NASA NTRS1995

High Power Amplifier Harmonic Output Level Measurement

A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

klystron amplifiers harmonic output power measurem↗
NASA NTRS1992

Gravimetric capillary method for kinematic viscosity measurements

A novel version of the capillary method for viscosity measurements of liquids is presented. Viscosity data can be deduced in a straightforward way from mass transfer data obtained by differential weighing during the gravity-induced flow of the liquid between two cylindrical chambers. Tests of this technique with water, carbon tetrachloride, and ethanol suggest that this arrangement provides an accuracy of about +/- 1 percent. The technique facilitates operation under sealed, isothermal conditions and, thus can readily be applied to reactive and/or high vapor pressure liquids.

Rosenberger, Franz↗
NASA NTRS1967

FM carrier deviation measured by differential probability method

Differential probability FM system measures deviation of a carrier modulated by a complex signal. The peak-to-peak amplitude is measured and related to the frequency shift of the carrier signal. The deviation is described in terms of a probability as well as a peak value.

Daquin, A. F., Jr.↗
NASA NTRS1971

Liquid-filled transient pressure measuring systems: A method for determining frequency response

An equation is given and experimentally verified for computing the resonant frequency of liquid-filled transient pressure measuring systems. Resonant frequencies of 100 to 1000 Hz are typical of those systems tested. The effect of noncondensable gas bubbles on system response is described. A method for determining transducer volumetric compliance is presented. An example system is described and analyzed to demonstrate the use of the theory.

Anderson, R. C.↗
NASA NTRS2006

Use of In Situ Cloud Condensation Nuclei, Extinction, and Aerosol Size Distribution Measurements to Test a Method for Retrieving Cloud Condensation Nuclei Profiles From Surface Measurements

If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei (CCN) concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

Ghan, Stephen J.↗
DOE OSTI2025

Python Measurement-Informed Modelling Method (PythonMIMM) v1.02

This Python program implements the calculations for electrical energy efficiency and electrical losses in the paper "Energy and power quality measurement for electrical distribution in AC and DC microgrid buildings" (https://www.sciencedirect.com/science/article/abs/pii/S0306261921015658). The inputs are metered voltage, current, or power data of meters located throughout the DC system. In the absence of metered data, the user must input some other information about the building such as the types of power converters or wire lengths. The program will build a loss model of the DC system based on metered data and electrical information. It will also generate an equivalent AC system and determine the losses and efficiency.

Gerber, Daniel [Lawrence Berkeley National Laborat↗
NASA NTRS2014

Remote Recession Sensing of Ablative Heat Shield Materials

Material recession and charring are two major processes determining the performance of ablative heat shield materials. Even in ground testing, the characterization of these two mechanisms relies on measurements of material thickness before and after testing, thus providing only information integrated over the test time. For recession measurements, optical methods such as imaging the sample surface during testing are under investigation but require high alignment and instrument effort, therefore being not established as a standard measurement method. For char depth measurements, the most common method so far consists in investigation of sectioned samples after testing or in the case of Stardust where core extractions were performed to determine char information. In flight, no reliable recession measurements are available, except total recession after recovering the heat shield on ground. Developments of mechanical recession sensors have been started but require substantial on board instrumentation adding mass and complexity. In this work, preliminary experiments to evaluate the feasibility of remote sensing of material recession and possibly char depth through optically observing the emission signatures of seeding materials in the post shock plasma is investigated. It is shown that this method can provide time resolved recession measurements without the necessity of accurate alignment procedures of the optical set-up and without any instrumentation on board of a spacecraft. Furthermore, recession data can be obtained without recovering flight hardware which would be a huge benefit for inexpensive heat shield material testing on board of small re-entry probes, e.g. on new micro-satellite re-entry probes as a possible future application of Cubesats or RBR

instrumentation↗
NASA NTRS1973

Technique for Obtaining Vertical Profiles of Backscattering and Extinction Cross Sections Using Slant Path Lidar Measurements

A method is presented for solving for vertical profiles of atmospheric particulate extinction and backscattering cross-sections utilizing monostatic lidar slant path measurements. The method is an extension of work by Fernald. It is shown that the number of assumptions necessary for an iterative solution of extinction and backscattering cross sections can be reduced if lidar slant path measurements are used to solve directly for optical depths. The technique is useful only if sufficiently accurate lidar measurements are available. With highly accurate measurements it is also possible to solve directly for extinction cross sections without an iterative solution of a transcendental equation if the proper reduction scheme is used. The required accuracy is discussed and results showing the effect of errors are presented.

Spinhirne, J. D.↗
DOE OSTI2025

Innovative Method for Reliable Measurement of PEM Water Electrolyzer Component Resistances

Understanding the sheet resistance of porous electrodes is essential for improving the performance of polymer electrolyte membrane (PEM) water electrolyzers and related technologies. Despite its importance, existing methods often fail to provide reliable and comprehensive data, especially for porous materials with complex morphologies and non‐uniform thicknesses. This study introduces a robust and straightforward method for determining the sheet resistance of porous electrodes using a novel probe concept based on industrial printed circuit board (PCB) technology. This probe measures resistance across ten distances, ranging from 250 µm to 2500 µm, enabling local mapping of resistance. The study focuses on the sheet resistance of key components in PEM water electrolyzers, including the gas diffusion layer (GDL), porous transport layer (PTL), and catalyst layers deposited on a membrane. Additionally, an image‐processing‐based method is presented to obtain the thickness distribution of the studied catalyst layers, facilitating a detailed analysis of the electrical in‐plane resistivity with thickness variations. Overall, this methodology has the potential to expedite material integration and bridge the gap between electrode engineering and single‐cell testing, thereby advancing the development of PEM water electrolyzers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1953

A Method of Calibrating Airspeed Installations on Airplanes at Transonic and Supersonic Speeds by the Use of Accelerometer and Attitude-Angle Measurements

A method is described for calibrating airspeed installation on airplanes at transonic and supersonic speeds in vertical-plane maneuvers in which use is made of measurements of normal and longitudinal accelerations and attitude angle. In this method all the required instrumentation is carried within the airplane. An analytical study of the effects of various sources of error on the accuracy of an airspeed calibration by the accelerometer method indicated that the required measurements can be made accurately enough to insure a satisfactory calibration.

Zalovick, John A↗
NASA NTRS2003

Thermal Property Measurement of Semiconductor Melt using Modified Laser Flash Method

This study further developed standard laser flash method to measure multiple thermal properties of semiconductor melts. The modified method can determine thermal diffusivity, thermal conductivity, and specific heat capacity of the melt simultaneously. The transient heat transfer process in the melt and its quartz container was numerically studied in detail. A fitting procedure based on numerical simulation results and the least root-mean-square error fitting to the experimental data was used to extract the values of specific heat capacity, thermal conductivity and thermal diffusivity. This modified method is a step forward from the standard laser flash method, which is usually used to measure thermal diffusivity of solids. The result for tellurium (Te) at 873 K: specific heat capacity 300.2 Joules per kilogram K, thermal conductivity 3.50 Watts per meter K, thermal diffusivity 2.04 x 10(exp -6) square meters per second, are within the range reported in literature. The uncertainty analysis showed the quantitative effect of sample geometry, transient temperature measured, and the energy of the laser pulse.

Lin, Bochuan↗
NASA NTRS1984

Magnetic constraints on early lunar evolution revisited: Limits on accuracy imposed by methods of paleointensity measurements

It is impossible to carry out conventional paleointensity experiments requiring repeated heating and cooling to 770 C without chemical, physical or microstructural changes on lunar samples. Non-thermal methods of paleointensity determination have been sought: the two anhysteretic remanent magnetization (ARM) methods, and the saturation isothermal remanent magnetization (IRMS) method. Experimental errors inherent in these alternative approaches have been investigated to estimate the accuracy limits on the calculated paleointensities. Results are indicated in this report.

Banerjee, S. K.↗
NASA NTRS1996

Pendant-Drop Surface-Tension Measurement On Molten Metal

Method of measuring surface tension of molten metal based on pendant-drop method implemented in quasi-containerless manner and augmented with digital processing of image data. Electrons bombard lower end of sample rod in vacuum, generating hanging drop of molten metal. Surface tension of drop computed from its shape. Technique minimizes effects of contamination.

Man, Kin Fung↗
DOE OSTI2021

Time-reversed nonlinear acoustic downhole pore pressure measurements

Apparatus (10) and methods for measurement of pore pressure in rock formations through a metal borehole casing (32) after a well is cased and cemented, are described. Such measurements may be accomplished by using the Dynamic Acoustic Elasticity (DAE) method for characterizing nonlinear parameters by perturbing a selected rock formation region with a High Amplitude, Low Frequency (HALF) acoustic strain wave, and probing this region using a Low Amplitude, High Frequency (LAHF) acoustic wave (18), (22). Time reversal techniques (36) may be employed for focusing acoustic energy into the formation in the vicinity of the pipe or open hole. The change in wave speed of the probe pulses as the HALF induced strain wave oscillation propagates through the formation, as a function of the induced strain, may be used to determine the nonlinear elastic parameters α, β, δ, and A of the pore pressure, from which the pore pressure may be determined in the region of the HALF wave.

Goodman, Harvey E.↗
DOE OSTI2024

Comparison of methods for the NMR measurement of motionally averaged dipolar couplings

Motionally averaged dipolar couplings are an important tool for understanding the complex dynamics of catalysts, polymers, and biomolecules. While there is a plethora of solid-state NMR pulse sequences available for their measurement, in can be difficult to gauge the methods’ strengths and weaknesses. In particular, there has not been a comprehensive comparison of their performance in natural abundance samples, where 1H homonuclear dipolar couplings are important and the use of large MAS rotors may be required for sensitivity reasons. In this work, we directly compared some of the more common methods for measuring C–H dipolar couplings in natural abundance samples using L-alanine (L-Ala) and the N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLF) tripeptide as model systems. Here, we evaluated their performance in terms of accuracy, resolution, sensitivity, and ease of implementation. We found that, despite the presence of 1H homonuclear dipolar interactions, all methods, with the exception of REDOR, were able to yield the reasonable dipolar coupling strengths for both mobile and static moieties. Of these methods, PDLF provides the most convenient workflow and precision at the expense of low sensitivity. In low-sensitivity cases, MAS-PISEMA and DIPSHIFT appear to be the better options.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1982

The application of nonintrusive optical methods for physical measurements in combustion

Laser optical diagnostic techniques have proven to be effective for making physical measurements in hostile combustion environments. Two major and complementary approaches have been applied; namely, single event imaging and multi-signal detection methods. Single event imaging methods (e.g., pulsed laser holography) can provide the essentially instantaneous observation of physical events, e.g., fuel atomization, droplet breakup, particle and surface combustion, condensed phase formation, and flow field visualization. Multi-signal detection methods, which involve the processing of signals produced by the light scattered from the interaction of particles and/or droplets with an incident coherent ray, can provide information on flow velocity, turbulence, fluid shear stresses, and particle/droplet size and velocity. Recent results using both approaches are presented.

Wuerer, J. E.↗