Intermittent type silica gel adsorption refrigerator Patent
Intermittent type silica gel adsorption refrigerator for providing temperature control for spacecraft components
Romvary, E., Jr.↗
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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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Investigation of intermittent enhancement of ion emission from a tungsten surface using the field ion microscope
Measuring intermittent enhancement of blinking effect upon addition of neon to imaging gas in helium-tungsten field-ion microscope
Weizer, V. G.↗
Intermittent cardiac block and efferent vagal activity in the anesthetized dog
Efferent vagal activity increase prior to intermittent cardiac block due to rise in blood pressure
Katona, P. G.↗
Miniature intermittent contact switch
Design of electric switch for providing intermittent contact is presented. Switch consists of flexible conductor surrounding, but separated from, fixed conductor. Flexing of outside conductor to contact fixed conductor completes circuit. Advantage is small size of switch compared to standard switches.
Sword, A.↗
Investigation of intermittent enhancement of ion emission from a tungsten surface using the field-ion microscope.
The blinking effect, or the intermittent enhancement of ion emission, which is observed when a few parts per million neon are added to the imaging gas in a helium-tungsten field-ion microscope, has been investigated. Measurements of the characteristic quantities involved - i.e., blinking rate, voltage limits, etc. - and their variation with temperature, field, and gas pressure, are described.
Weizer, V. G.↗
Anomalous type III bursts explained in terms of intermittent solar wind streams observed by Pioneer spacecraft.
Occasional solar radio bursts drift downward in frequency (like type III bursts), but the drift slows or ceases or it may even reverse. These anomalous forms are called L-bursts, U-bursts, etc., and are observed as low as 1 MHz by spacecraft. The conventional explanation involves guidance of relativistic exciting particles by solar magnetic fields that do not have the spiral shape expected in undisturbed conditions. A reasonable alternative explanation is possible and, indeed, it follows directly from the inferences which have been drawn from the Stanford dual-frequency experiment flown on four Pioneer spacecraft. Analysis of temporal variations in these data leads to the conclusion that narrow streams of enhanced concentration have lifetimes which are typically about one day and the streams seem to be intermittently ejected by long-enduring sources at the sun. Each enhancement is thought to lie along a spiral and to have a beginning and an end. It may happen that relativistic exciters encounter the tail of such a discrete streamer; the concentration encountered by such exciters would initially decline but, at the streamer tail, it would level off and perhaps increase. The plasma frequency versus time (the burst frequency) would then cease to drop in the typical type III profile and would level off or increase (as in a U-burst).
Croft, T. A.↗
Corotation of an intermittent solar wind source
The measured electron content of the solar wind in mid-1970 exhibited a region of relatively high electron density that reappeared at intervals of about 27.8 days. It is shown that the repeating event cannot be reconciled with the concept of a long-enduring steady flow, even though the recurrence period is close to the rotation period of the sun. This evidence of transients is inferred from the short duration of each appearance of the interval of higher density; each should last for roughly one corotation interval if it is caused by a steady stream. The radio path was approximately 0.8 AU long, and the corotation interval exceeded 3 days. Other aspects of the content data patterns support the view that such transient events are common in the solar wind. The mid-1970 repeating event is an unusually good example of the intermittent character of flow regions in the solar wind that fluctuate on a time scale of days but endure as identifiable regions for many months. A sputtering corotating source of thin solar plasma streams could explain this series of events; it could also be explained in terms of a stream that is steady in density and speed but undulating north-south so that it passes into and out of the 0.8 AU radio path in a matter of a day or less.
Croft, T. A.↗
The use of digital techniques to examine the intermittent region of a turbulent jet
Voltage signals, sampled at a high rate in the intermittent region of a round jet, are analyzed to provide instantaneous velocity vector information and measures of the vorticity and dissipation scales. A clustering routine to assess the feasibility of using the voltage readings to define the vortical, nonvortical state of the flow is also utilized. The results indicate that the clustering routine is partially successful; more sophisticated discrimination techniques will be required for a complete specification.
Foss, J. F.↗
Intermittent bonding for high toughness/high strength composites
An analysis of toughness and strength in intermittently bonded brittle filament/brittle matrix composites is presented that shows the importance of the coating material in achieving high toughness properties. Some observations are made on methods of measuring the components of toughness in composites. Both a mathematical model and experimental results are incorporated into the discussion.
Atkins, A. G.↗
Screening analysis and selection of emission reduction concepts for intermittent combustion aircraft engines
An analysis was conducted to screen, evaluate, and select three engine exhaust emission reduction concepts from a group of 14 candidate alternatives. A comprehensive literature search was conducted to survey the emission reduction technology state-of-the-art and establish contact with firms working on intermittent combustion engine development and pollution reduction problems. Concept development, advantages, disadvantages, and expected emission reduction responses are stated. A set of cost effectiveness criteria was developed, appraised for relative importance, and traded off against each concept so that its merit could be determined. A decision model was used to aid the evaluators in managing the criteria, making consistent judgements, calculating merit scores, and ranking the concepts. An Improved Fuel Injection System, Improved Cooling Combustion Chamber, and a Variable Timing Ignition System were recommended to NASA for approval and further concept development. An alternate concept, Air Injection, was also recommended.
Rezy, B. J.↗
Hybrid drive for motor vehicles with a preponderantly intermittent method of operation
A flywheel hybrid propulsion system is compared with a conventional propulsion system in a test vehicle under intermittent operation. An energy balance is presented for the conventional propulsion system. Results so far indicate especially high energy conversion of the gyro component under dynamic operation along with favorable internal combustion engine conditions.
Schreck, H.↗
Increased fracture toughness of graphite-epoxy composites through intermittent interlaminar bonding
Intermittent interlaminar bonding, which can lead to a large increase in the fracture surface area, was achieved through the introduction of thin perforated Mylar between the layers of a multi-layer continuous-filament graphite-epoxy composite. For the best optimum condition included in this study, fracture toughness was increased from about 100 kJ/sq m for untreated specimens to an average of about 500 kJ/sq m, while tensile strength dropped from 500 MPa to 400 MPa, and elastic modulus remained the same at about 75 GPa. An approximate analysis is presented to explain the observed improvement in toughness.
Felbeck, D. K.↗
An analysis of intermittent updating for the shallow water equations
The method of intermittent updating for a model system is analyzed. How updating one variable of the system affects the other variables, what the factors are which influence the rate of convergence of this procedure, and how measurement error affects the procedure are considered.
Bube, K. P.↗
Development potential of Intermittent Combustion (I.C.) aircraft engines for commuter transport applications
An update on general aviation (g/a) and commuter aircraft propulsion research effort is reviewed. The following topics are discussed: on several advanced intermittent combustion engines emphasizing lightweight diesels and rotary stratified charge engines. The current state-of-the-art is evaluated for lightweight, aircraft suitable versions of each engine. This information is used to project the engine characteristics that can be expected on near-term and long-term time horizons. The key enabling technology requirements are identified for each engine on the long-term time horizon.
Willis, E. A.↗
An Io thermal model with intermittent volcanism
Observations have indicated that heat flow out of Io at present may be several times greater than the heat input from enhanced tidal heating; this may indicate that the observed heat flow is intermittent, rather than continuous. A two-dimensional time-dependent thermal model of Io was constructed to examine the relationship between enhanced tidal heating, heat flow within the body, and surface volcanism. From the models one can conclude that (1) a simple homogeneous body cannot maintain enhanced tidal heating in a thin crust, but such heating is possible if the crust contains an insulating layer, as of sulfur; (2) this sulfur layer will be subject to melting by heat from the interior, resulting in hotspots which can expel heat much more rapidly than tidal heating inputs it; and (3) the location of these hotspots will vary in time and space; they can appear anywhere on the surface, even if tidal heating is concentrated at the poles, and they seem to occur roughly 10% of the time.
Consolmagno, G. J.↗
Tester Detects Steady-Short Or Intermittent-Open Circuits
Momentary open circuits or steady short circuits trigger buzzer. Simple, portable, lightweight testing circuit sounds long-duration alarm when it detects steady short circuit or momentary open circuit in coaxial cable or other two-conductor transmission line. Tester sensitive to discontinuities lasting 10 microseconds or longer. Used extensively for detecting intermittent open shorts in accelerometer and extensometer cables. Also used as ordinary buzzer-type continuity checker to detect steady short or open circuits.
Anderson, Bobby L.↗
Automatic recognition of intermittent failures - An experimental study of field data
A methodology is proposed for recognizing the symptoms of persistent problems in large systems. The system error rate is used to identify the error states among which relationships may exist. Statistical techniques are used to validate and quantify the strength of the relationship among these error states. As input, the approach takes the raw error logs containing a single entry for each error that is detected as an isolated event. As output, it produces a list of symptoms that characterize persistent errors. Thus, given a failure, it is determined whether the failure is an intermittent manifestation of a common fault or whether it is an isolated (transient) incident. The technique is shown to work on two CYBER systems and an IBM 3081 multiprocessor system. Comparisons to real failure/repair information obtained from field engineers show that, in about 85 percent of the cases, the error symptoms recognized by this approach correspond to real problems. The remaining 15 percent of the cases, although not directly supported by field data, are confirmed as being valid problems.
Iyer, Ravishankar K.↗
Intermittent acceleration as a countermeasure to soleus muscle atrophy
The effectiveness of using intermittent acceleration as a countermeasure to muscle atrophy was investigated in rats subjected to 7 days of hindlimb suspension interrupted by daily periods of 1.2 g acceleration, for 15-min periods evenly spaced over 12-hr interval. It was found that this regimen, when repeated for 7 days, failed to completely maintain the mass of soleus muscle, which was 84 percent of control.
D'Aunno, Dominick S.↗