Instrument for measuring dispersional distortions in optical fibers and cables

NASA Astrophysics Data System (ADS)

Alishev, Y. V.; Maryenko, A. A.; Smirnov, Y. V.; Uryadov, V. N.; Sinkevich, V. I.

1985-03-01

An instrument was developed and built for measuring the dispersional distortions in optical fibers and cables on the basis of pulse widening. The instrument consists of a laser as a light source, a master oscillator, an optical transmitter, an optical shunt with mode mixer, an optical receiver, a fiber length measuring device, a smoothly adjustable delay line, and a stroboscopic oscillograph. The optical transmitter contains a semiconductor laser with GaAs-GaAlAs diheterostructure and modulator with pulse generating avalanche-breakdown transistors. The optical receiver contains a germanium photodiode with internal amplification and photoreceiver amplifier with microwave bipolar germanium transistors. Matching of the instrument to the tested fiber line is done by passing radiation into the latter from an auxiliary small He-Ne laser through a directional coupler.

Preliminary sonic boom correlation of predicted and measured levels for STS-1 entry

NASA Technical Reports Server (NTRS)

Garcia, F., Jr.; Morrison, K. M.; Jones, J. H.; Henderson, H. R.

1982-01-01

A preliminary analysis correlating peaks from sonic boom pressure signatures recorded during the descent trajectory of the Orbiter Columbia, which landed in the dry lake bed at Edwards Air Force Base (EAFB), California, with measured wind tunnel signatures extrapolated from flight altitudes to the ground has been made for Mach numbers ranging from 1.3 to 6. The flight pressure signatures were recorded by microphones positioned at ground level near the groundtrack, whereas the wind tunnel signatures were measured during a test of a 0.0041-scale model Orbiter. The agreement between overpressure estimates based on wind tunnel data using preliminary flight trajectory data and oscillograph traces from ground measurements appears reasonable at this time for the range of Mach numbers considered. More detailed studies using final flight trajectory data and digitized ground measured data will be performed.

A new, morphologically cryptic bush-cricket discovered on the basis of its song in the Carpathian Mountains (Insecta, Orthoptera, Tettigoniidae).

PubMed

Iorgu, Ionuţ Ştefan; Iorgu, Elena Iulia; Szövényi, Gergely; Orci, Kirill Márk

2017-01-01

A new, morphologically cryptic species of phaneropterine bush-crickets is described from the grasslands of the Romanian Eastern Carpathians. Despite the morphological and acoustic similarities with the recently described Isophya nagyi Szövényi, Puskás & Orci, I. bucovinensis sp. n. is characterized by a peculiar male calling song, with faster syllable repetition rate (160-220 syllables per minute, at 22-27°C) and less complex syllable structure (composed of only two elements instead of three observable in I. nagyi ). The morphological description of the new species is supplemented with an oscillographic and spectrographic analysis of the male calling song and male-female pair-forming acoustic duet. An acoustic signal-based identification key is provided for all the presently known species of the Isophya camptoxypha species group, including the new species.

A new, morphologically cryptic bush-cricket discovered on the basis of its song in the Carpathian Mountains (Insecta, Orthoptera, Tettigoniidae)

PubMed Central

Iorgu, Ionuţ Ştefan; Iorgu, Elena Iulia; Szövényi, Gergely; Orci, Kirill Márk

2017-01-01

Abstract A new, morphologically cryptic species of phaneropterine bush-crickets is described from the grasslands of the Romanian Eastern Carpathians. Despite the morphological and acoustic similarities with the recently described Isophya nagyi Szövényi, Puskás & Orci, I. bucovinensis sp. n. is characterized by a peculiar male calling song, with faster syllable repetition rate (160–220 syllables per minute, at 22–27°C) and less complex syllable structure (composed of only two elements instead of three observable in I. nagyi). The morphological description of the new species is supplemented with an oscillographic and spectrographic analysis of the male calling song and male–female pair-forming acoustic duet. An acoustic signal-based identification key is provided for all the presently known species of the Isophya camptoxypha species group, including the new species. PMID:28769716

MELANOPHORE BANDS AND AREAS DUE TO NERVE CUTTING, IN RELATION TO THE PROTRACTED ACTIVITY OF NERVES

PubMed Central

Parker, G. H.

1941-01-01

1. When appropriate chromatic nerves are cut caudal bands, cephalic areas, and the pelvic fins of the catfish Ameiurus darken. In pale fishes all these areas will sooner or later blanch. By recutting their nerves all such blanched areas will darken again. 2. These observations show that the darkening of caudal bands, areas, and fins on cutting their nerves is not due to paralysis (Brücke), to the obstruction of central influences such as inhibition (Zoond and Eyre), nor to vasomotor disturbances (Hogben), but to activities emanating from the cut itself. 3. The chief agents concerned with the color changes in Ameiurus are three: intermedin from the pituitary gland, acetylcholine from the dispersing nerves (cholinergic fibers), and adrenalin from the concentrating nerves (adrenergic fibers). The first two darken the fish; the third blanches it. In darkening the dispersing nerves appear to initiate the process and to be followed and substantially supplemented by intermedin. 4. Caudal bands blanch by lateral invasion, cephalic areas by lateral invasion and internal disintegration, and pelvic fins by a uniform process of general loss of tint equivalent to internal disintegration. 5. Adrenalin may be carried in such an oil as olive oil and may therefore act as a lipohumor; it is soluble in water and hence may act as a hydrohumor. In lateral invasion (caudal bands, cephalic areas) it probably acts as a lipohumor and in internal disintegration (cephalic areas, pelvic fins) it probably plays the part of a hydrohumor. 6. The duration of the activity of dispersing nerves after they had been cut was tested by means of the oscillograph, by anesthetizing blocks, and by cold-blocks. The nerves of Ameiurus proved to be unsatisfactory for oscillograph tests. An anesthetizing block, magnesium sulfate, is only partly satisfactory. A cold-block, 0°C., is successful to a limited degree. 7. By means of a cold-block it can be shown that dispersing autonomic nerve fibers in Ameiurus can continue in activity for at least 6½ hours. It is not known how much longer they may remain active. So far as the duration of their activity is concerned dispersing nerve fibers in this fish are unlike other types of nerve fibers usually studied. PMID:19873231

Preliminary Performance Data on Westinghouse Electronic Power Regulator Operating on J34-WE-32 Turbojet Engine in Altitude Wind Tunnel

NASA Technical Reports Server (NTRS)

Ketchum, James R.; Blivas, Darnold; Pack, George J.

1950-01-01

The behavior of the Westinghouse electronic power regulator operating on a J34-WE-32 turbojet engine was investigated in the NACA Lewis altitude wind tunnel at the request of the Bureau of Aeronautics, Department of the Navy. The object of the program was to determine the, steady-state stability and transient characteristics of the engine under control at various altitudes and ram pressure ratios, without afterburning. Recordings of the response of the following parameters to step changes in power lever position throughout the available operating range of the engine were obtained; ram pressure ratio, compressor-discharge pressure, exhaust-nozzle area, engine speed, turbine-outlet temperature, fuel-valve position, jet thrust, air flow, turbine-discharge pressure, fuel flow, throttle position, and boost-pump pressure. Representative preliminary data showing the actual time response of these variables are presented. These data are presented in the form of reproductions of oscillographic traces.

Puncture discharges in surface dielectrics as contaminant sources in spacecraft environments

NASA Technical Reports Server (NTRS)

Yadlowsky, E. J.; Hazelton, R. C.; Churchill, R. J.

1978-01-01

Spacecraft in geosynchronous orbits are known to become charged to large negative potentials during the local midnight region of the satellite orbit. Such discharges have been studied by the electron beam irradiation of dielectric samples in a vacuum environment. In addition to static measurements and photographic examination of the puncture discharges in Teflon samples, the transient characteristics of the electrical discharges are determined from oscillographs of voltage and current and by charged particle measurements employing a biased Faraday cup and a retarding potential analyzer. Using these latter techniques, studies of angular and energy distributions of charged particles have indicated an initial burst of high energy electrons (5 x 10 to the 13th power per discharge at energies greater than 300 eV) followed by a less intense burst of lower energy negative particles. Positive ions are emitted from the discharge site in an initial high velocity burst followed by a lower velocity burst tentatively identified as carbon.

The Spatial Expansion of a Discharge in the Generation and the Channel Structure (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlumbohm, H.

1962-02-01

The spatial expansion of a discharge was investigated under homogeneous field conditions, using an anode with a small central area separated from the remainder and wide band double beam oscillographic techniques. The discharge currents were initiated by electrons released along traces of single alpha particles in the gas between the electrodes. The k particles enter the gap volume through a small hole in the middle of the separated center of the anode. The measurements have shown that a secondary photon emission from the cathode causes a spreading over the total gap volume within the first few electron generations (N 2,more » air, and CO 2 at lower pressures). If a streamer mechanism occurs (O 2 and CO 2 at higher pressures), the discharge remains localized to the trace of the alpha particle, in which the avalanches yielded by the primary electrons have produced a high density of positive ions. New details of steamer mechanism are revealed by analyzing the rapid increase of the current during streamer formation.« less

Design and construction of a novel rotary magnetostrictive motor

NASA Astrophysics Data System (ADS)

Zhou, Nanjia; Blatchley, Charles C.; Ibeh, Christopher C.

2009-04-01

Magnetostriction can be used to induce linear incremental motion, which is effective in giant magnetostrictive inchworm motors. Such motors possess the advantage of combining small step incremental motion with large force. However, continuous rotation may be preferred in practical applications. This paper describes a novel magnetostrictive rotary motor using terfenol-D (Tb0.3Dy0.7Fe1.9) material as the driving element. The motor is constructed of two giant magnetostrictive actuators with shell structured flexure-hinge and leaf springs. These two actuators are placed in a perpendicular position to minimize the coupling displacement of the two actuators. The principal design parameters of the actuators and strain amplifiers are optimally determined, and its static analysis is undertaken through finite element analysis software. The small movements of the magnetostrictive actuators are magnified by about three times using oval shell structured amplifiers. When two sinusoidal wave currents with 90° phase shift are applied to the magnetostrictive actuators, purely rotational movement can be produced as in the orbit of a Lissajous diagram in an oscillograph, and this movement is used to drive the rotor of the motor. A prototype has been constructed and tested.

ARC-1964-A-33038-22

NASA Image and Video Library

1964-08-14

Aerial view of Gasdynamics facility in 1964 and the 20 inch helium tunnel Part of the Thermal Protection Laboratory used to research materials for heat shield applications and for aerodynamic heating and materials studies of vehicles in planetary atmospheres.  This laboratory is comprised of five separate facilities: an Aerodynamic Heating Tunnel, a Heat Transfer Tunnel, two Supersonic Turbulent Ducts, and a High-Power CO2 Gasdynamic Laser. All these facilities are driven by arc-heaters, with the exception of the large, combustion-type laser. The arc-heated facilities are powered by a 20 Megawatt DC power supply. Their effluent gas stream (test gases; Air, N2, He, CO2 and mixtures; flow rates from 0.05 to 5.0 lbs/sec) discharges into a five-stage stream-ejector-driven vacuum system. The vacuum system and power supply are common to the test faciities in building N-238. All of the facilities have high pressure water available at flow rates up to 4, 000 gals/min. The data obtained from these facilities are recorded on magnetic tape or oscillographs. All forms of data can be handled whether from thermo-couples, pressure cells, pyrometers, or radiometers, etc. in addition, closed circuit T. V. monitors and various film cameras are available. (operational since 1962)

Careful measurement of first hyperpolarizability spectrum by hyper-Rayleigh scattering (HRS)

NASA Astrophysics Data System (ADS)

Zhu, Jing; Lu, Changgui; Cui, Yiping

2008-01-01

The first hyperpolarizability (β) spectrum of an azobenzene derivative around its two-photon resonance region is detected carefully by hyper-Rayleigh scattering. The present work uses a fluorescence spectrometer (Edinburgh instruments, F900) as the detector instead of interference filter and photoelectric multiplier tube (PMT). For each wavelength, HRS emission spectrum accompanied with two-photon fluorescence (TPF) is carefully detected by changing the detection wavelength around half of the incident wavelength. Full width to half maximum (FWHM) of the spectrum is about 0.4nm, which is similar to that of the laser. When the incident wavelength moves into the two-photon resonance region, TPF signal increases quickly and should be eliminated. In order to receive accurate β spectrum, the data detected by the oscillograph should be made some emendations, such as TPF, incident energy, absorption and pulse width. Compared with the β spectrum detected in previous works, the spectrum received in this work presents a clearer profile. The β spectrum exhibits a similar profile as its UV-visible spectrum just with blue-shift of wavelength. It could be explained that the electronic vibration structure in two-photon progress is different from that in one-photon progress, while the broadening mechanism may be similar, considering the resonant two-state model (RTSM).

Implementation and extension of the impulse transfer function method for future application to the space shuttle project. Volume 1: Analysis and correlation studies

NASA Technical Reports Server (NTRS)

Mantus, M.; Pardo, H.

1973-01-01

Computer programming, data processing, and a correlation study that employed data collected in the first phase test were used to demonstrate that standard test procedures and equipment could be used to collect a significant number of transfer functions from tests of the Lunar Module test article LTA-11. The testing consisted of suspending the vehicle from the apex fittings of the outrigger trusses through a set of air springs to simulate the free-free state. Impulsive loadings were delivered, one at a time, at each of the landing gear's attachment points, in three mutually perpendicular directions; thus a total of 36 impulses were applied to the vehicle. Time histories of each pulse were recorded on magnetic tape along with 40 channels of strain gage response and 28 channels of accelerometer response. Since an automated data processing system was not available, oscillograph playbacks were made of all 2400 time histories as a check on the validity of the data taken. In addition, one channel of instrumentation was processed to determine its response to a set of forcing functions from a prior LTA-11 drop test. This prediction was compared with drop test results as a first measure of accuracy.

Spasmolytic effect of Petroselinum crispum (Parsley) on rat's ileum at different calcium chloride concentrations.

PubMed

Moazedi, A A; Mirzaie, D N; Seyyednejad, S M; Zadkarami, M R; Amirzargar, A

2007-11-15

Traditional herbal medicines such as Petroselinum crispum (Parsley) have been used for treatment of intestinal disorders in Iran. To date no pharmacological evidence for their effectiveness has been reported. The aim of this study was to examine the relaxant effect of hydroalcoholic extract of Petroselinum crispum on isolated adult male Wistar rat's ileum contraction by KCl 60 (mM). The extract was prepared from parsley seed with 80% ethanol. A portion of ileum was removed and placed in an organ bath containing Tyrode solution (37 degrees C, pH = 7.4) bubbled with air. From a resting tension of 1 g, isotonic Transducer and Harvard Universal Oscillograph were used for recording contraction of ileum after administration of 60 mM KCl. Various concentration of extract were added to the bath. This experiment showed that, the extract in a dose-dependent manner decreased the induced-KCl ileums contraction (n = 7, p < 0.001). Also adding extract before influence of KCl, cause reduced effect of KCl (n = 7, p < 0.001). In addition, the Tyrode solution without CaCl2 and high concentration of K+, various concentration of extract significantly (n = 7, p < 0.001) decreased the CaCl2-induced contraction. Therefore, it seems that the relaxation effect of extract alcoholic parsley seed on the contraction of ileum is performed by blocking of voltage-gated calcium channels.

Test stand for gas-discharge chamber of TEA CO2 lasers with pulse-periodical energy supply

NASA Astrophysics Data System (ADS)

Shorin, Vladimyr P.; Bystrov, N. D.; Zhuravlyov, O. A.; Nekrasov, V. V.

1997-05-01

Test stand for function optimization (incomposition of gas- dynamic circuit (GDC) of operating characteristics of full- size discharge chamber of flowing TEA carbon-dioxide lasers (power up to 100 kW) was created in Samara State Aerospace University (former Kuibyshev Aviation Institute). Test stand includes an inside-type GDC, low inductive generators of voltage pulses of preionization and main discharges, two-flow rate system of gas supply and noise immunity diagnostic system. Module construction of units of GDC, power supplies of preionization and main discharges allows to change configuration of stand's systems for providing given properties of gas flow and its energy supply. This test stand can also be used in servicing of laser system. The diagnostic system of this stand allows us to analyze energy properties of discharge by means of oscillographic measurements of voltage and current with following processing of discharges' volt- ampere characteristics by means of a computer; rate of non- stationary gas-dynamic disturbances in discharge gap of discharge chamber was measured by means of pulse holographic system (UlG-1M) with data processing of schliren- and interferogram (density fluctuation sensitivity approximately 10-2) and sensor measurement system of gas-dynamic shock and acoustics process with resonance frequency exceeding 100 kHz. Research results of process of plasma plate wave and channel structures interaction with mediums, including actuation non-stationary gas-dynamic flows, cavitation erosion of preionization electrodes' dielectric substructure, ancillary heating of channels by main volumetric discharge are presented as well.

X-1A in flight with flight data superimposed

NASA Image and Video Library

1953-12-12

This photo of the X-1A includes graphs of the flight data from Maj. Charles E. Yeager's Mach 2.44 flight on December 12, 1953. (This was only a few days short of the 50th anniversary of the Wright brothers' first powered flight.) After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or 8 times the normal pull of gravity at sea level. (At these G forces, a 200-pound human would, in effect, weigh 1,600 pounds if a scale were placed under him in the direction of the force vector.) Producing these graphs was a slow, difficult process. The raw data from on-board instrumentation recorded on oscillograph film. Human computers then reduced the data and recorded it on data sheets, correcting for such factors as temperature and instrument errors. They used adding machines or slide rules for their calculations, pocket calculators being 20 years in the future.

Data Recording Room in the 10-by 10-Foot Supersonic Wind Tunnel

NASA Image and Video Library

1973-04-21

The test data recording equipment located in the office building of the 10-by 10-Foot Supersonic Wind Tunnel at the NASA Lewis Research Center. The data system was the state of the art when the facility began operating in 1955 and was upgraded over time. NASA engineers used solenoid valves to measure pressures from different locations within the test section. Up 48 measurements could be fed into a single transducer. The 10-by 10 data recorders could handle up to 200 data channels at once. The Central Automatic Digital Data Encoder (CADDE) converted this direct current raw data from the test section into digital format on magnetic tape. The digital information was sent to the Lewis Central Computer Facility for additional processing. It could also be displayed in the control room via strip charts or oscillographs. The 16-by 56-foot long ERA 1103 UNIVAC mainframe computer processed most of the digital data. The paper tape with the raw data was fed into the ERA 1103 which performed the needed calculations. The information was then sent back to the control room. There was a lag of several minutes before the computed information was available, but it was exponentially faster than the hand calculations performed by the female computers. The 10- by 10-foot tunnel, which had its official opening in May 1956, was built under the Congressional Unitary Plan Act which coordinated wind tunnel construction at the NACA, Air Force, industry, and universities. The 10- by 10 was the largest of the three NACA tunnels built under the act.

NACA Computer Operates an IBM Telereader

NASA Image and Video Library

1952-02-21

A staff member from the Computing Section at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory operates an International Business Machines (IBM) telereader at the 8- by 6-Foot Supersonic Wind Tunnel. The telereader was used to measure recorded data from motion picture film or oscillographs. The machine could perform 50 measurements per minute. The component to her right is a telerecordex that was used convert the telereader measurements into decimal form and record the data on computer punch cards. During test runs in the 8- by 6-foot tunnel, or the other large test facilities, pressure sensors on the test article were connected to mercury-filled manometer tubes located below the test section. The mercury would rise or fall in relation to the pressure fluctuations in the test section. Initially, female staff members, known as “computers,” transcribed all the measurements by hand. The process became automated with the introduction of the telereader and other data reduction equipment in the early 1950s. The Computer Section staff members were still needed to operate the machines. The Computing Section was introduced during World War II to relieve short-handed research engineers of some of the tedious work. The computers made the initial computations and plotted the data graphically. The researcher then analyzed the data and either summarized the findings in a report or made modifications or ran the test again. The computers and analysts were located in the Altitude Wind Tunnel Shop and Office Building office wing during the 1940s. They were transferred to the new facility when the 8- by 6-Foot tunnel began operations in 1948.

Interaction of air shock waves and porous compressible materials

NASA Astrophysics Data System (ADS)

Gvozdeva, L. G.; Faresov, Yu. M.; Fokeyev, V. P.

1986-05-01

Interaction of air shock waves and porous compressible materials was studied in an experiment with two foam-plastic materials: PPU-3M-1 polyurethane (density 33 kg/cu m) and much more rigid PKhV-1 polyvinyl chloride (density 50 kg/cu m). Tests were performed in a shock tube with 0.1x0.1 m square cross-section, a single diaphragm separating its 8 m long low-pressure segment with inspection zone and 1.5 m long high-pressure segment. The instrumentation included an array of piezoelectric pressure transducers and a digital frequency meter for velocity measurements, a Tectronix 451A oscillograph, and IAB-451 shadowgraph, and a ZhFR camera with slit scanning. Air was used as compressing gas, its initial pressure being varied from 10(3) Pa to 10(5) Pa, helium and nitrogen were used as propelling gas. The impact velocity of shock waves was varied over the N(M) = 2-5 range of the Mach number. The maximum amplitude of the pressure pulse increased as the thickness of the foam layer was increased up to 80 mm and then remained constant with further increases of that thickness, at a level depending on the material and on the intitial conditions. A maximum pressure rise by a factor of approximately 10 was attained, with 1.3 x 10(3) Pa initial pressure and an impact velocity N(M) = 5. Reducing the initial pressure to below (0.1-0.3) x 10(3) Pa, with the impact velocity maintained at N(M) = 5, reduced the pressure rise to a factor below 3. The results are interpreted taking into account elasticity forces in the solid skeleton phase and gas filtration through the pores.

Structure and properties of optical-discharge plasma in CO2-laser beam near target surface

NASA Astrophysics Data System (ADS)

Danshchikov, Ye. V.; Dymshakov, V. A.; Lebedev, F. V.; Ryazanov, A. V.

1986-05-01

An experimental study of optical-discharge plasma in a CO2-laser beam at a target surface was made for the purpose of exploring the not yet understood role of this plasma in the laser-target interaction process. Such a plasma was produced by means of a quasi-continuous CO2-laser with an unstable resonator, its power being maintained constant for 1 ms periods. Its radiation was focused on the surfaces of thick and seeding thin Al, Ti, and Ta targets inclined at an approximately 70 deg. angle to the beam, inside a hermetic chamber containing air, argon, or helium under atmospheric pressure. The radiation intensity distribution over the focal plane and the nearest caustic surface in the laser beam was measured along with the plasma parameters, the latter by the methods of spectral analysis and photoelectric recording. The instrumentation for this purpose included an MDR-3 monochromator with an entrance slit, a double electron-optical converter, a memory oscillograph, and an SI-10-30 ribbon lamp as radiation reference standard. The results yielded integral diametral intensity distributions of the emission lines Ti-II (457.2 nm), Ti-I (464 nm), Ar-II (462 nm), radial and axial temperature profiles of optical discharge in metal vapor in surrounding gas, and the radial temperature profile of irradiated metal surface at successive instants of time. The results reveal marked differences between the structures and the properties of optical-discharge plasma in metal vapor and in surrounding gas, optical discharge in the former being characterized by localization within the laser beam and optical discharge in the latter being characterized by a drift away from the target.

The Electrical Activity of a Denervated Ear 1

PubMed Central

Rawdon-Smith, A. F.; Hawkins, J. E.

1939-01-01

The electrical response from the cochlea of a cat which had previously been denervated by intracranial crushing of the auditory nerve was submitted to a lengthy study, the results of which may be summarized as follows:- The responses to acoustical stimulation derived from electrodes placed on the round window margin and in the chin muscles were studied by means of an amplifier and cathode ray oscillograph, in the usual way. Transient stimuli whose polarity could be reversed were employed to demonstrate the absence of any electrical component of neural origin such as is invariably present in a normal ear. In all other respects, however, the responses were unaffected, and both threshold contours (the so-called “electrical audiogram”) and equal response contours for approximately pure-tone stimuli demonstrated close comparability with those for normal ears. Harmonic analysis of the cochlear response yielded results departing from the normal only in such respects as would be expected in view of the complete absence of nervous component in the analysed wave. From these data, it is argued that this animal presented a case in which normal electrical responses were obtained from the peripheral organ, despite virtually complete degeneration of the auditory nerve, and, it follows, complete unilateral deafness. Subsequent histological examination confirmed these observations, and it is urged, therefore, that the validity of the view that the cochlear response provides an index of the hearing ability of an animal, as is sometimes stated, is open to question. Additionally, this experiment finally discredits the hypothesis that the cochlear response itself is, in any sense, neural in origin; it further indicates the necessity for caution in the interpretation of results obtained from normal ears, where the cochlear response, however derived, is in some degree adulterated by the simultaneous presence of an action potential component. ImagesFig. 8 PMID:19991849

THE EFFECTS OF POLARIZATION UPON THE STEEL WIRE-NITRIC ACID MODEL OF NERVE ACTIVITY.

PubMed

Bishop, G H

1927-11-20

The active process in a short length of steel wire passivated by 65 per cent nitric acid has been observed under the influence of a polarizing current, and the form of the potential recorded by the cathode ray oscillograph. In the passive wire, 80 per cent of the total potential drop takes place at the anode, 20 per cent at the cathode. The change from active to passive states, as measured by the potential change, is very abrupt compared to the duration of activity and the potential curve at a point on the wire is probably almost rectangular. The duration of the refractory state is decreased at the anode and increased at the cathode, as in nerve. This fact is against the idea that reactivity after passivation results from a partial reduction of an oxide layer. Soft iron wire passivated by anodal polarization repassivates after activation in acid of a dilution that fails to passivate it initially. It soon becomes rhythmic with a very short refractory phase, and then reacts continuously. Such a wire exhibits a very sharp alternation between a dark brown oxide coat during activity, and a bright clean surface during passivation. A passive steel wire in nitric acid shows many of the characteristics of an inert electrode such as platinum, and it may be inferred that, superposed upon the primary passivation potential, there exists an electrode or oxidation-reduction potential equilibrium between the effects of the various constituents of the solution. It is suggested that the phenomena of nerve-like reactivity in this system may involve an alternation between two protective coatings of the steel wire. During activity, the surface becomes mechanically coated with a brown oxide. If this coating does not adhere, due to gas convection or to rapid solution of the oxide, passivation does not result. Under sufficiently intense oxidizing conditions, a second oxide coat may form in the interstices of the first, and cover the surface as the first coating dissolves off. This furnishes the electrochemical protection of passivation, which is followed by the gradual attainment of electrode equilibrium with the solution.

THE EFFECTS OF POLARIZATION UPON THE STEEL WIRE-NITRIC ACID MODEL OF NERVE ACTIVITY

PubMed Central

Bishop, George H.

1927-01-01

The active process in a short length of steel wire passivated by 65 per cent nitric acid has been observed under the influence of a polarizing current, and the form of the potential recorded by the cathode ray oscillograph. In the passive wire, 80 per cent of the total potential drop takes place at the anode, 20 per cent at the cathode. The change from active to passive states, as measured by the potential change, is very abrupt compared to the duration of activity and the potential curve at a point on the wire is probably almost rectangular. The duration of the refractory state is decreased at the anode and increased at the cathode, as in nerve. This fact is against the idea that reactivity after passivation results from a partial reduction of an oxide layer. Soft iron wire passivated by anodal polarization repassivates after activation in acid of a dilution that fails to passivate it initially. It soon becomes rhythmic with a very short refractory phase, and then reacts continuously. Such a wire exhibits a very sharp alternation between a dark brown oxide coat during activity, and a bright clean surface during passivation. A passive steel wire in nitric acid shows many of the characteristics of an inert electrode such as platinum, and it may be inferred that, superposed upon the primary passivation potential, there exists an electrode or oxidation-reduction potential equilibrium between the effects of the various constituents of the solution. It is suggested that the phenomena of nerve-like reactivity in this system may involve an alternation between two protective coatings of the steel wire. During activity, the surface becomes mechanically coated with a brown oxide. If this coating does not adhere, due to gas convection or to rapid solution of the oxide, passivation does not result. Under sufficiently intense oxidizing conditions, a second oxide coat may form in the interstices of the first, and cover the surface as the first coating dissolves off. This furnishes the electrochemical protection of passivation, which is followed by the gradual attainment of electrode equilibrium with the solution. PMID:19872388

Earthquake locations determined by the Southern Alaska seismograph network for October 1971 through May 1989

USGS Publications Warehouse

Fogleman, Kent A.; Lahr, John C.; Stephens, Christopher D.; Page, Robert A.

1993-01-01

This report describes the instrumentation and evolution of the U.S. Geological Survey’s regional seismograph network in southern Alaska, provides phase and hypocenter data for seismic events from October 1971 through May 1989, reviews the location methods used, and discusses the completeness of the catalog and the accuracy of the computed hypocenters. Included are arrival time data for explosions detonated under the Trans-Alaska Crustal Transect (TACT) in 1984 and 1985.The U.S. Geological Survey (USGS) operated a regional network of seismographs in southern Alaska from 1971 to the mid 1990s. The principal purpose of this network was to record seismic data to be used to precisely locate earthquakes in the seismic zones of southern Alaska, delineate seismically active faults, assess seismic risks, document potential premonitory earthquake phenomena, investigate current tectonic deformation, and study the structure and physical properties of the crust and upper mantle. A task fundamental to all of these goals was the routine cataloging of parameters for earthquakes located within and adjacent to the seismograph network.The initial network of 10 stations, 7 around Cook Inlet and 3 near Valdez, was installed in 1971. In subsequent summers additions or modifications to the network were made. By the fall of 1973, 26 stations extended from western Cook Inlet to eastern Prince William Sound, and 4 stations were located to the east between Cordova and Yakutat. A year later 20 additional stations were installed. Thirteen of these were placed along the eastern Gulf of Alaska with support from the National Oceanic and Atmospheric Administration (NOAA) under the Outer Continental Shelf Environmental Assessment Program to investigate the seismicity of the outer continental shelf, a region of interest for oil exploration. Since then the region covered by the network remained relatively fixed while efforts were made to make the stations more reliable through improved electronic instrumentation and strengthened antenna systems. The majority of the stations installed since 1980 were operated only temporarily (from one to several years) for special studies in various areas within the network. Due to reduced funding, the network was trimmed substantially in the summer of 1985 with the closure of 15 stations, 13 of which were located in and around the Yakataga seismic gap. To further reduce costs, two telephone circuits were dropped and multiple radio relays were installed in their place. This economy reduced the reliability of these telemetry links. In addition, data collection from the areas around Cordova and Yakutat was compromised by the necessity of relying on triggered event recording using PC-based systems (Rogers, 1993) that were not fully developed and which proved to be less reliable than anticipated.The principal means of recording throughout the time period of this catalog was 20-channel oscillographs on 16-mm film (Teledyne Geotech Develocorder, Model RF400 and 4000D). Initially one Develocorder was operated at the USGS Alaskan headquarters in Anchorage, but in 1972 recording was shifted to the National Oceanic and Atmospheric Administration (NOAA) Palmer Observatory (currently the West Coast and Alaska Tsunami Warning Center). The Develocorders were turned off at the end of May 1989, and after that time recording was done in digital format at the Geophysical Institute of the University of Alaska in Fairbanks (GIUA). Thus, this catalog covers the entire period of film recording.

X-1A in flight with flight data superimposed

NASA Technical Reports Server (NTRS)

1953-01-01

This photo of the X-1A includes graphs of the flight data from Maj. Charles E. Yeager's Mach 2.44 flight on December 12, 1953. (This was only a few days short of the 50th anniversary of the Wright brothers' first powered flight.) After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or 8 times the normal pull of gravity at sea level. (At these G forces, a 200-pound human would, in effect, weigh 1,600 pounds if a scale were placed under him in the direction of the force vector.) Producing these graphs was a slow, difficult process. The raw data from on-board instrumentation recorded on oscillograph film. Human computers then reduced the data and recorded it on data sheets, correcting for such factors as temperature and instrument errors. They used adding machines or slide rules for their calculations, pocket calculators being 20 years in the future. Three second generation Bell Aircraft Corporations X-1s were built, though four were requested. They were the X-1A (48-1384); X-1B (48-1385); X-1C (canceled and never built); X-1D (48-1386). These aircraft were similar to the X-1s, except they were five feet longer, had conventional canopies, and were powered by Reaction Motors, Inc. XLR11-RM-5 rocket engines. The RM-5, like the previous engines, had no throttle and was controlled by igniting one or more of the four thrust chambers at will. The original program outline called for the X-1A and X-1B to be used for dynamic stability and air loads investigations. The X-1D was to be used for heat transfer research while the X-1C was intended as a high-speed armament systems test bed. All of these aircraft like the original X-1s, were launched from a Boeing B-29 or Boeing B-50 'mothership' to take maximum advantage of their limited flying time with a rocket engine. Most launches were made from the JTB-29A (45-21800). The other launch aircraft was EB-50A (46-006). X-1A The Bell X-1A was similar to the Bell X-1, except for having turbo-driven fuel pumps (instead of a system using nitrogen under pressure), a new cockpit canopy, longer fuselage and increased fuel capacity. The X-1A arrived at Edwards Air Force Base, California on January 7, 1953, with the first glide flight being successfully completed by Bell pilot, Jean 'Skip' Ziegler. The airplane also made five powered flights with Ziegler at the controls. The USAF was attempting a Mach 2 flight and USAF test pilot Charles 'Chuck' Yeager was eager. He reached speed of Mach 2.435, at a altitude of 75,000 feet on December 12, 1953, a speed record at the time. But all was not well, the aircraft encountered an inertial coupling phenomenon and went out of control. Once the X-1A had entered the denser atmosphere (35,000 feet) it slowly stabilized and Yeager was able to return to Edwards. The aircraft had experienced high-speed roll-coupling, something aerodynamicists had predicted, but this was the first actual encounter. On August 26, 1954, Major Arthur Murray, USAF test pilot flew the X-1A to an altitude record of 90,440 feet. NACA High-Speed Flight Station received the aircraft in September 1954 and returned it to Bell for the installation of an ejection seat. NACA test pilot Joseph Walker made a familiarization flight on July 20, 1955 followed by another scheduled flight on August 8, 1955. Shortly before launch the X-1A suffered an explosion. The extent of the damage prohibited landing the crippled aircraft. The X-1A was jettisoned into the desert, exploding and burning on impact. Walker and the B-29 crew returned to base in satisfactory condition. Four pilots had completed 29 flights (including aborts). X-1B The Bell Aircraft Corporation X-1B was similar to the Bell X-1A except for the installation of wingtips extensions for its last three flight. The NACA portion of the X-1B flight test program was for the purpose of aerodynamic heating research, accumulating data during 1956-1958. The X-1B was fitted with special instrumentation for exploratory aerodynamic heating tests. It had over 300 thermocouples installed on it. It was the first aircraft to fly with a reaction control system, a prototype of the control system used on the X-15 and other piloted aircraft. Midway through its flight test program, the X-1B was equipped with an Reaction Motors, Inc. XLR-11-RM-9 engine which differed, from the other XLR-11s, only in having an electric spark, low-tension interrupter type ignition in place of the older high-tension type. On January 27, 1959 the X-1B was given to the Air Force Museum at Wright-Patterson Air Force Base, Ohio, for preservation and public display. This aircraft completed a total of 27 glide and powered flights made by eight USAF test pilots and two NACA test pilots. X-1C Following the X-1B was the projected X-1C, which was canceled while still in the mock-up stage. The birth of transonic and supersonic-capable aircraft like the North American F-86 Sabre and the North American F-100 Super Sabre eventually eliminated the need for the X-1C. X-1D The X-1D was the first advanced model of the X-1 family to roll from Bell Aircraft Corporation's plant. It arrived at Edwards, California, in July 1951 suspended from the bomb bay shackles of a Boeing EB-50A, (46-006) aircraft. On July 24, 1951, with Bell test pilot Jean 'Skip' Ziegler at the controls, the X-1D had the only successful flight of its career. It was an unpowered glide flight, and on landing the nose gear failed with the plane sliding to a stop. The aircraft was repaired and ready once more for flight when USAF test pilot Frank 'Pete' Everest boarded the aircraft for launch on August 22, 1951. The drop from the Boeing B-50 was canceled because of mechanical problems. On the way back to the landing field and after the crew had jettisoned the propellants, an explosion occurred with flames being reported by the chase plane pilot. The X-1D was dropped to crash on the desert near the south end of Rogers Dry Lakebed. The second generation Bell Aircraft Corporations X-1s increased man's understanding of the stability and control characteristics, and aerodynamic heating at high-speeds and the environment of high-altitude flight. INVESTIGATION Since there had been a loss of several aircraft during the period of the rocket flights, the NACA instituted an investigation. It sent samples of a suspicious looking oily residue from a liquid oxygen tank to a Los Angeles, California, laboratory and to the chemical laboratory at Edwards Air Force Base, California. The Edwards laboratory identified the substance as TCP--tricresyl phosphate--a substance used to impregnate leather. All the destroyed rocket planes--as well as those still flying--had gaskets made of Ulmer leather. The TCP had been the culprit, because it could easily detonate in the presence of liquid oxygen. Armed with this knowledge, the Air Force and the NACA avoided all future catastrophic blasts.