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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Bench-Scale Apparatus for Rapid, Simultaneous, Comprehensive Vapor–Liquid Equilibrium and Kinetic Property Measurements to Advance CO 2 Capture Solvent Technology

We present here, the design, fabrication, and testing of a new "pressure, volume, temperature (PVT)" apparatus that enables rapid standardized testing for viscosity, vapor–liquid equilibria, and kinetics for water-lean carbon capture solvents. This unit is the first of its kind where equilibrium data are collected during operation as a PTx (pressure–temperature–composition) cell while kinetic data are collected simultaneously with an internal mini wetted-wall contactor (WWC) using controlled adjustments of CO 2 injections to allow for measurements of gas flux (in and out of the liquid). Additionally, in situ measurements of viscosity data are also continuously collected while a solvent is in circulation during gas absorption. This cell empowers comprehensive testing of critical CO 2 capture solvent properties in a single measurement, ensuring all data are collected at the same temperature, pressure, and CO 2 loading. This apparatus also expedites screening of materials since less than 50 mL of sample is needed as compared to 2–3 L needed to get similar data from a conventional WWC. In conclusion, we describe here the methodology of data collected on this new PVT cell, nicknamed “Gary” in honor of Professor Gary Rochelle, for multiple water-lean amine solvents, which we compare to data collected from conventional instrumentation for amine testing.

Zheng, Richard [STARS Technology Corporation, Rich↗
NASA NTRS1975

The effect of shearing strain-rate on the ultimate shearing resistance of clay

An approach for investigating the shearing resistance of cohesive soils subjected to a high rate of shearing strain is described. A fast step-loading torque apparatus was used to induce a state of pure shear in a hollow cylindrical soil specimen. The relationship between shearing resistance and rate of shear deformation was established for various soil densities expressed in terms of initial void ratio or water content. For rate of shearing deformation studies, the shearing resistance increases initially with shearing velocity, but subsequently reaches a terminal value as the shearing velocity increases. The terminal shearing resistance is also found to increase as the density of the soil increases. The results of this investigation are useful in the rheological study of clay. It is particularly important for mobility problems of soil runways, since the soil resistance is found to be sensitive to the rate of shearing.

Cheng, R. Y. K.↗
NASA NTRS1976

The effect of shearing strain-rate on the ultimate shearing resistance of clay

The shearing resistance of cohesive soils subjected to a high rate of shearing strain was investigated. A fast step-loading torque apparatus was used to induce a state of pure shear in a hollow cylindrical soil specimen. The relationship between shearing resistance and rate of shear deformation was established for various soil densities expressed in terms of initial void ratio or water content. For rate of shearing deformation studies to date, the shearing resistance increases initially with shearing velocity but subsequently reaches a terminal value as the shearing velocity increases. The terminal shearing resistance is also found to increase as the density of the soil increases. The results are useful in the rheological study of clay. It is particularly important for mobility problems of soil runways, since the soil resistance is found to be sensitive to the rate of shearing.

Cheng, R. Y. K.↗
NASA NTRS1978

Friction and wear of radiofrequency-sputtered borides, silicides, and carbides

The friction and wear properties of several refractory compound coatings were examined. These compounds were applied to 440 C bearing steel surfaces by radiofrequency (RF) sputtering. The refractory compounds were the titanium and molybdenum borides, the titanium and molybdenum silicides, and the titanium, molybdenum, and boron carbides. Friction testing was done with a pin-on-disk wear apparatus at loads from 0.1 to 5.0 newtons. Generally, the best wear properties were obtained when the coatings were bias sputtered onto 440 C disks that had been preoxidized. Adherence was improved because of the better bonding of the coatings to the iron oxide formed during preoxidation. As a class the carbides provided wear protection to the highest loads. Titanium boride coatings provided low friction and good wear properties to moderate loads.

Brainard, W. A.↗
NASA NTRS1935

Strength Tests of Thin-walled Duralumin Cylinders in Combined Transverse Shear and Bending

This report is the fourth of a series presenting the results of strength tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results on 100 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that as the ratio of moment to shear varies from small to large values the failure changes from a shear to a bending type. In the report a chart is presented that shows the corresponding changes in strength.

CONES, TRUNCATED - STRENGTH TESTS↗
NASA NTRS1933

Strength Tests of Thin-walled Duralumin Cylinders in Pure Bending

This report is the third of a series presenting the results of strengths tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results obtained from pure bending tests on 58 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that the stress on the extreme fiber at failure as calculated by the ordinary theory of bending is from 30 to 80 percent greater than the compressive stress at failure for thin-walled cylinders in compression. The tests also show that length/radius ratio has no consistent effect upon the bending strength and that the size of the wrinkles that form on the compression half of a cylinder in bending is approximately equal to the size of the wrinkles that form in the complete circumference of a cylinder of the same dimensions in compression.

CONES, TRUNCATED - STRENGTH TESTS↗
NASA NTRS1994

New Testing Tool For Composite Interfaces

Mechanical strength of fiber/matrix interface key factor in overall strength and toughness of composite material. Desktop fiber pushout apparatus generates load and acoustic-emission (soundwave) data as function of translation-table displacement. Video camera gives view of specimen. Compact, easy to operate, and inexpensive. Appropriate for wide range of composites, including metal, intermetallic, and ceramic matrix composites. Not restricted to aerospace/aeronautics applications.

Eldridge, Jeffrey I.↗
NASA NTRS1987

Strain measurements in composites subjected to compressive loading using moire interferometry

Experimental apparatus to apply a uniaxial compressive load to composite laminates and measure the resulting in-plane displacement fields using moireinterferometry were designed and built. Quasi-isotropic graphite/epoxy and graphite/PEEK laminates were subjected to near-ultimate compressive creep loadings at room temperatures. Creep loads were applied for times up to 28 hrs. Strains were calculated from the measured displacements, and compared with theoretical results.

Klein, R. J.↗
NASA NTRS1996

Randomness fault detection system

A method and apparatus are provided for detecting a fault on a power line carrying a line parameter such as a load current. The apparatus monitors and analyzes the load current to obtain an energy value. The energy value is compared to a threshold value stored in a buffer. If the energy value is greater than the threshold value a counter is incremented. If the energy value is greater than a high value threshold or less than a low value threshold then a second counter is incremented. If the difference between two subsequent energy values is greater than a constant then a third counter is incremented. A fault signal is issued if the counter is greater than a counter limit value and either the second counter is greater than a second limit value or the third counter is greater than a third limit value.

Russell, B. Don↗
NASA NTRS2012

Method and apparatus for calibrating multi-axis load cells in a dexterous robot

A robotic system includes a dexterous robot having robotic joints, angle sensors adapted for measuring joint angles at a corresponding one of the joints, load cells for measuring a set of strain values imparted to a corresponding one of the load cells during a predetermined pose of the robot, and a host machine. The host machine is electrically connected to the load cells and angle sensors, and receives the joint angle values and strain values during the predetermined pose. The robot presses together mating pairs of load cells to form the poses. The host machine executes an algorithm to process the joint angles and strain values, and from the set of all calibration matrices that minimize error in force balance equations, selects the set of calibration matrices that is closest in a value to a pre-specified value. A method for calibrating the load cells via the algorithm is also provided.

Wampler, II, Charles W.↗
NASA NTRS1980

Steady-state wear and friction in boundary lubrication studies

A friction and wear study was made at 20 C to obtain improved reproducibility and reliability in boundary lubrication testing. Ester-base and C-ether-base fluids were used to lubricate a pure iron rider in sliding contact with a rotating M-50 steel disk in a friction and wear apparatus. Conditions included loads of 1/2 and 1 kg and sliding velocities of 3.6 to 18.2 m/min in a dry air atmosphere and stepwise time intervals from 1 to 250 min for wear measurements. The wear rate results were compared with those from previous studies where a single 25 min test period was used. Satisfactory test conditions for studying friction and wear in boundary lubrication for this apparatus were found to be 1 kg load; sliding velocities of 7.1 to 9.1 m/min (50 rpm disk speed); and use of a time stepwise test procedure. Highly reproducible steady-state wear rates and steady-state friction coefficients were determined under boundary conditions. Wear rates and coefficients of friction were constant following initially high values during run-in periods.

Loomis, W. R.↗
NASA NTRS2009

Apparatus for integrating a rigid structure into a flexible wall of an inflatable structure

For an inflatable structure having a flexible outer shell or wall structure having a flexible restraint layer comprising interwoven, load-bearing straps, apparatus for integrating one or more substantially rigid members into the flexible shell. For each rigid member, a corresponding opening is formed through the flexible shell for receiving the rigid member. A plurality of connection devices are mounted on the rigid member for receiving respective ones of the load-bearing straps. In one embodiment, the connection devices comprise inner connecting mechanisms and outer connecting mechanisms, the inner and outer connecting mechanisms being mounted on the substantially rigid structure and spaced along a peripheral edge portion of the structure in an interleafed array in which respective outer connecting mechanisms are interposed between adjacent pairs of inner connecting mechanisms, the outer connecting mechanisms projecting outwardly from the peripheral edge portion of the substantially rigid structure beyond the adjacent inner connecting mechanisms to form a staggered array of connecting mechanisms extending along the panel structure edge portion. In one embodiment, the inner and outer connecting mechanisms form part of an integrated, structure rotatably mounted on the rigid member peripheral edge portion.

Johnson, Christopher J.↗
NASA NTRS1983

Apparatus for accurately preloading auger attachment means for frangible protective material

Apparatus for preloading a spring loaded threaded member is described. The apparatus is formed of three telescoping tubes. The innermost tube has means to prevent rotation of the threaded member. The middle tube is threadedly engaged with the threaded member and by axial movement applies a preload thereto. The outer tube engages a nut which may be rotated to retain the threaded member in axial position to maintain the preload.

Wood, K. E.↗
NASA NTRS1986

Measuring Gearbox Torque Loss

Accuracy increased by measuring small torque differences directly. Input and output torques are balanced by mechanical linkage in transmission-testing apparatus. Force applied to load cell proportional to frictional torque loss in transmission. Apparatus measures portion of input torque lost to friction in automotive transmissions or other gearbox. Apparatus more sensitive than previous measuring systems.

Schmidt, L. F.↗
NASA NTRS1991

O-ring gasket test fixture

An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.

Turner, James Eric↗