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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Stowage and Deployment of Slit Tube Booms

A system comprising a boom having a first end, a longitudinal length, and a slit that extends along the longitudinal length of the boom; a drum having an elliptic cross section and a longitudinal length; an attachment mechanism coupled with the first end of the boom and the drum such that the boom and the drum are substantially perpendicular relative to one another; an inner shaft having a longitudinal length, the inner shaft disposed within the drum, the longitudinal length of the inner shaft is aligned substantially parallel with the longitudinal length of the drum, the inner shaft at least partially rotatable relative to the drum, and the inner shaft is at least partially rotatable with the drum; and at least two cords coupled with the inner shaft and portions of the boom near the first end of the boom.

Adams, Larry↗
NASA NTRS1989

Adaptation to vection-induced symptoms of motion sickness

The effects of repeated exposures to a rotating circular vection drum on the symptoms of motion sickness and tachygastria in humans were investigated. Subjects were sitting in a drum and were exposed to 15 min baseline (no rotation), followed by 15 min drum rotation at 60 deg/s, and, then, by 15 min recovery. Gastric myoelectric activity was continuously recorded with the electrogastrogram. Subjects who were exposed to the drum three times with intervals of 4-24 days all showed symptoms of tachygastria and failed to show an amelioration of motion sickness symptoms. On the other hand subjects who had only 48 h between the three sessions of drum exposure, experienced a reduction in motion-sickness symptoms and in tachygastsria upon repeated exposure to the drum, indicating that training effected a symptomatic and physiological adaptation. It is suggested that preflight adaptation to visual-vestibular sensory mismatch may reduce motion sickness in astronauts.

Stern, Robert M.↗
NASA NTRS1988

Space Software for Automotive Design

John Thousand of Wolverine Western Corp. put his aerospace group to work on an unfamiliar job, designing a brake drum using computer design techniques. Computer design involves creation of a mathematical model of a product and analyzing its effectiveness in simulated operation. Technique enables study of performance and structural behavior of a number of different designs before settling on a final configuration. Wolverine employees attacked a traditional brake drum problem, the sudden buildup of heat during fast and repeated braking. Part of brake drum not confined tends to change its shape under combination of heat, physical pressure and rotational forces, a condition known as bellmouthing. Since bellmouthing is a major factor in braking effectiveness, a solution of problem would be a major advance in automotive engineering. A former NASA employee, now a Wolverine employee, knew of a series of NASA computer programs ideally suited to confronting bellmouthing. Originally developed as aids to rocket engine nozzle design, it's capable of analyzing problems generated in a rocket engine or automotive brake drum by heat, expansion, pressure and rotational forces. Use of these computer programs led to new brake drum concept featuring a more durable axle, and heat transfer ribs, or fins, on hub of drum.

Source record↗
NASA NTRS1974

Solar array deployment from a spinning spacecraft

Cylindrical drum, wrapped with flexible solar array of solar cells mounted on Mylar sheet, is held by two end-fittings with cable (under tension) passing through axel of drum. Drum is held to end-fittings by axial cable through drum axel; drum is released for deployment when cable is cut at each end and end-fittings spring outward.

Carlin, A. H.↗
NASA NTRS1986

Bidirectional, Automatic Coal-Mining Machine

Proposed coal-mining machine operates in both forward and reverse directions along mine face. New design increases efficiency and productivity, because does not stop cutting as it retreats to starting position after completing pass along face. To further increase efficiency, automatic miner carries its own machinery for crushing coal and feeding it to slurry-transport tube. Dual-drum mining machine cuts coal in two layers, crushes, mixes with water, and feeds it as slurry to haulage tube. At end of pass, foward drum raised so it becomes rear drum, and rear drum lowered, becoming forward drum for return pass.

Collins, Earl R., Jr.↗
NASA NTRS2006

Mode I Toughness Measurements of Core/Facesheet Bonds in Honeycomb Sandwich Structures

Composite sandwich structures will be used in many future applications in aerospace, marine and offshore industries due to the fact that the strength and stiffness to mass ratios surpass any other structural type. Sandwich structure also offers advantages over traditional stiffened panels such as ease of manufacturing and repair. During the last three decades, sandwich structure has been used extensively for secondary structure in aircraft (fuselage floors, rudders and radome structure). Sandwich structure is also used as primary structure in rotorcraft, the most common example being the trailing edge of rotor blades. As with other types of composite construction, sandwich structure exhibits several types of failure mode such as facesheet wrinkling, core crushing and sandwich buckling. Facesheet/core debonding has also been observed in the marine and aerospace industry. During this failure mode, peel stresses applied to an existing facesheet/core debond or an interface low in toughness, results in the facesheet being peeled from the core material, possibly leading to a significant loss in structural integrity of the sandwich panel. In an incident during a test on a liquid hydrogen fuel tank of the X-33 prototype vehicle, the outer graphite/epoxy facesheet and honeycomb core became debonded from the inner facesheet along significant areas, leading to failure of the tank. As a consequence of the accident; significant efforts were made to characterize the toughness of the facesheet/core bond. Currently, the only standardized method available for assessing the quality of the facesheet/core interface is the climbing drum peel test (ASTM D1781). During this test a sandwich beam is removed from a panel and the lip of one of the facesheets is attached to a drum, as shown in Fig. 1. The drum is then rotated along the sandwich beam, causing the facesheet to peel from the core. This method has two major drawbacks. First, it is not possible to obtain quantitative fracture data from the test and so the results can only be used in a qualitative manner. Second, only sandwich structure with thin facesheets can be tested (to facilitate wrapping of the facesheet around the climbing drum). In recognition of the need for a more quantitative facesheet/core fracture test, several workers have devised experimental techniques for characterizing the toughness of the facesheet/core interface. In all of these cases, the tests are designed to yield a mode I-dominated fracture toughness of the facesheet/core interface in a manner similar to that used to determine mode I fracture toughness of composite laminates. In the current work, a modified double cantilever beam is used to measure the mode I-dominated fracture toughness of the interface in a sandwich consisting of glass/phenolic honeycomb core reinforced with graphite epoxy facesheets. Two specimen configurations were tested as shown in Fig 2. The first configuration consisted of reinforcing the facesheets with aluminum blocks (Fig. 2a). In the second configuration unreinforced specimens were tested (Fig. 2b). Climbing drum peel tests were also conducted to compare the fracture behavior observed between this test and the modified double cantilever beam. This paper outlines the test procedures and data reduction strategies used to compute fracture toughness values from the tests. The effect of specimen reinforcement on fracture toughness of the facesheet/core interface is discussed.

Nettles, Alan T.↗
NASA NTRS2007

Two Devices for Removing Sludge From Bioreactor Wastewater

Two devices a magnetic separator and a special filter denoted a self-regenerating separator (SRS) have been developed for separating sludge from the stream of wastewater from a bioreactor. These devices were originally intended for use in microgravity, but have also been demonstrated to function in normal Earth gravity. The magnetic separator (see Figure 1) includes a thin-walled nonmagnetic, stainless-steel cylindrical drum that rotates within a cylindrical housing. The wastewater enters the separator through a recirculation inlet, and about 80 percent of the wastewater flow leaves through a recirculation outlet. Inside the drum, a magnet holder positions strong permanent magnets stationary and, except near a recirculation outlet, close to the inner drum surface. To enable magnetic separation, magnetite (a ferromagnetic and magnetically soft iron oxide) powder is mixed into the bioreactor wastewater. The magnetite becomes incorporated into the sludge by condensation, onto the powder particles, of microbe flocks that constitute the sludge. As a result, the magnets inside the drum magnetically attract the sludge onto the outer surface of the drum.

Archer, Shivaun↗
NASA NTRS1973

Fast-spectrum space-power-reactor concepts using boron control devices

Several fast-spectrum space power reactor concepts that use boron carbide control devices were examined to determine the neutronic feasibility of the designs. The designs considered were (1) a 199-fuel-pin, 12-poison-reflector-control-drum reactor; (2) a 232-fuel-pin reactor with 12 reflector drums and three in-core control rods; (3) a 337-fuel-pin design with 12 incore control rods; and a 181-fuel-pin design with six drums closely coupled to the core to increase reactivity per drum. Adequate reactivity control and excess reactivity could be obtained for each concept, and the goals of 50,000 hours at 2.17 thermal megawatts with a lithium-7 coolant outlet temperature of 1222 K could be met without exceeding the 1-percent-clad-creep criterion. Heating rates in the boron carbide were calculated, but a heat transfer analysis was not done.

Mayo, W.↗
NASA NTRS1973

Investigation of fluctuations in angular velocity in magnetic memory devices

The fluctuations in the angular velocity of individual assemblies of a precision mechanical system were analyzed. The system was composed of an electric motor and a magnetic drum which were connected by a flexible coupling. A dynamic model was constructed which took into account the absence of torsion in the rigid shafts of the electric motor drive rotor and the magnetic drum. The motion was described by Lagrange differential equations of the second kind. Curves are developed to show the nature of amplitude fluctuation of the magnetic drum angular velocity at a specific excitation frequency. Additional curves show the amplitudes of fluctuation of the magnetic drum angular velocity compared to the quantity of damping at specific frequencies.

Meshkis, Y. A.↗
NASA NTRS1977

The GEOS-20 m Cable Boom Mechanism

The GEOS Cable Boom Mechanism which allows the controlled deployment of a 20 m long cable in a centrifugal force field is described. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

Schmidt, G. K.↗
NASA NTRS1977

GEOS-20 m cable boom mechanism

The GEOS cable boom mechanism allows the controlled deployment of a 20 m long cable in a centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface.

Schmidt, B. K.↗
NASA NTRS1979

Antenna deployment mechanism for use with a spacecraft

A mechanical system is disclosed to deploy an antenna on a support which may, for example, be a spacecraft. A series of telescoping tubes are nested one within the other when the antenna is in a retracted stowed position. The outermost tube is rigidly attached to the support and the inner tubes are latched in the stowed position by a caging mechanism. The antenna is driven toward a deployed position by a dual motor driven cable which is terminated in a driving tube at the lower end of the innermost tube, from whence the cable is trained about pulleys at the tops and bottoms of successively large tubes of the antenna. The cable is wound on a drum at the lower end of the antenna and coaxial therewith. During deployment of the antenna, the drum rotates, thereby reeling in the deployment cable. The initial movement of the cable causes cam releasing of the latches in the caging device. Thereafter, the antenna tubes are extended until the final deployed position of the antenna is reached. A ratchet attached to the drum prevents reverse rotation of the drum and locks the antenna in the deployed position until the ratchet is released.

Leavy, W. A.↗
NASA NTRS1986

Aeolian processes aboard a space station: Saltation and particle trajectory analysis

The Carousel wind tunnel (CWT) proposed to study aeolian processes aboard a space station consists of two concentric rotating drums. The space between the two drums comprises the wind tunnel test section. Differential rates of rotation of the two drums would provide a wind velocity with respect to either drum surface. Preliminary results of measured velocity profiles made in a CWT prototype indicate that the wall bounded boundary layer profiles are suitable to simulate flat plate turbulent boundary layer flow. The two dimensional flat plate Cartesian coordinate equations of motion of a particle moving through the air are explained. In order to assess the suitability of CWT in the analysis of the trajectories of windblown particles, a series of calculations were conducted comparing cases for gravity with those of zero gravity. Results from the calculations demonstrate that a wind tunnel of the carousel design could be fabricted to operate in a space station environment and that experiments could be conducted which would yield significant results contributing to the understanding of the physics of particle dynamics.

White, B. R.↗
NASA NTRS1987

Aeolian processes aboard a Space Station: Saltation and particle trajectory analysis

The Carousel Wind Tunnel (CWT) proposed to study aeolian processes aboard a Space Station consists of two concentric rotating drums. The space between the two drums comprises the wind tunnel section. Differential rates of rotation of the two drums would provide a wind velocity with respect to either drum surface. Preliminary results of measured velocity profiles made in a CWT prototype indicate that the wall bounded boundary layer profiles are suitable to simuate flat plate turbulent boundary layer flow. The two dimensional flate plate Cartesian coordinate equations of motion of a particle moving through the air are explained. In order to assess the suitability of CWT in the analysis of the trajectories of windblown particles, a series of calculations were conducted comparing cases for gravity with those of zero gravity. Results from the calculations demonstrate that a wind tunnel of the carousel design could be fabricated to operate in a space station environment and that experiments could be conducted which would yield significant results contributing to the understanding of the physics of particle dynamics.

White, Bruce R.↗
NASA NTRS1998

Development of a Coupled Hydrological/Sediment Yield Model for a Watershed at Regional Level

Development of a hydrologic model for the study of environmental conservation requires a comprehensive understanding of individual-storm affecting hydrologic and sedimentologic processes. The hydrologic models that we are currently coupling are the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) and the Distributed Runoff Model (DRUM). SHEELS runs continuously to estimate surface energy fluxes and sub-surface soil water fluxes, while DRUM operates during and following precipitation events to predict surface runoff and peak flow through channel routing. The lateral re-distribution of surface water determined by DRUM is passed to SHEELS, which then adjusts soil water contents throughout the profile. The model SHEELS is well documented in Smith et al. (1993) and Laymen and Crosson (1995). The model DRUM is well documented in Vieux et al. (1990) and Vieux and Gauer (1994). The coupled hydrologic model, SHEELS/DRUM, does not simulate sedimentologic processes. The simulation of the sedimentologic process is important for environmental conservation planning and management. Therefore, we attempted to develop a conceptual frame work for coupling a sediment yield model with SHEELS/DRUM to estimate individual-storm sediment yield from a watershed at a regional level. The sediment yield model that will be used for this study is the Universal Soil Loss Equation (USLE) with some modifications to enable the model to predict individual-storm sediment yield. The predicted sediment yield does not include wind erosion and erosion caused by irrigation and snow melt. Units used for this study are those given by Foster et al. (1981) for SI units.

Rajbhandaril, Narayan↗
NASA NTRS2004

Sensory-Feedback Exoskeletal Arm Controller

An electromechanical exoskeletal arm apparatus has been designed for use in controlling a remote robotic manipulator arm. The apparatus, called a force-feedback exoskeleton arm master (F-EAM) is comfortable to wear and easy to don and doff. It provides control signals from the wearer s arm to a robot arm or a computer simulator (e.g., a virtual-reality system); it also provides force and torque feedback from sensors on the robot arm or from the computer simulator to the wearer s arm. The F-EAM enables the wearer to make the robot arm gently touch objects and finely manipulate them without exerting excessive forces. The F-EAM features a lightweight design in which the motors and gear heads that generate force and torque feedback are made smaller than they ordinarily would be: this is achieved by driving the motors to power levels greater than would ordinarily be used in order to obtain higher torques, and by providing active liquid cooling of the motors to prevent overheating at the high drive levels. The F-EAM (see figure) includes an assembly that resembles a backpack and is worn like a backpack, plus an exoskeletal arm mechanism. The FEAM has five degrees of freedom (DOFs) that correspond to those of the human arm: 1. The first DOF is that of the side-to-side rotation of the upper arm about the shoulder (rotation about axis 1). The reflected torque for this DOF is provided by motor 1 via drum 1 and a planar four-bar linkage. 2. The second DOF is that of the up-and-down rotation of the arm about the shoulder. The reflected torque for this DOF is provided by motor 2 via drum 2. 3. The third DOF is that of twisting of the upper arm about its longitudinal axis. This DOF is implemented in a cable remote-center mechanism (CRCM). The reflected torque for this DOF is provided by motor 3, which drives the upper-arm cuff and the mechanism below it. A bladder inflatable by gas or liquid is placed between the cuff and the wearer s upper arm to compensate for misalignment between the exoskeletal mechanism and the shoulder. 4. The fourth DOF is that of flexion and extension of the elbow. The reflected torque for this DOF is provided by motor 4 and drum 4, which are mounted on a bracket that can slide longitudinally by a pin-and-slot engagement with the upper-arm cuff to compensate for slight variations in the position of the kinematic center of the elbow. Attached to drum 4 is an adapter plate to which is attached a CRCM for the lower arm. 5. The lower-arm CRCM implements the fifth DOF, which is the twist of the forearm about its longitudinal axis. Motor 5 provides the reflected torque for this DOF by driving the lower-arm cuff. A rod transmits twist and torsion between the lower-arm cuff and the hand cuff. With this system, the motion of the wearer s joints and the reflected torques applied to these joints can be measured and controlled in a relatively simple manner. This is because the anthropomorphic design of the mechanism imitates the kinematics of the human arm, eliminating the need for kinematic conversion of joint-torque and joint-angle data.

An, Bin↗
NASA NTRS1973

Image data rate converter: A concept

Establish data tracks on periphery of rotating drum and axially displace entire drum to place given track in alignment with either fixed or rotating read/record head. Accurate control of speed drum and rotating head can be accomplished by using separate synchronous motors driven by digitally-set oscillators to provide required difference in speed.

Billingsley, F. C.↗
NASA NTRS1979

Development of sensitized pick coal interface detector system

One approach for detection of the coal interface is measurement of the pick cutting hoads and shock through the use of pick strain gage load cells and accelerometers. The cutting drum of a long wall mining machine contains a number of cutting picks. In order to measure pick loads and shocks, one pick was instrumented and telementry used to transmit the signals from the drum to an instrument-type tape recorder. A data system using FM telemetry was designed to transfer cutting bit load and shock information from the drum of a longwall shearer coal mining machine to a chassis mounted data recorder.

Burchill, R. F.↗