Ultrasonics fakes the ocean's tentperature
Post on 30-Mar-2017
of its two preset frequencies or any two transceivers can be coupled through the special headset. The operator can transmit on either of the monitored frequencies by use of a special switch.
The command pack was designed, developed, and produced in four months. It replaces approximately 300 pounds of equipment heretofore used to do the same job. Units have been delivered to the First Air Commando Group at Hurl-burt Field, Eglin Air Force Base, Fla., for field testing in this country before being shipped to Southeast Asia for further evaluation. They were built under a U.S. Air Force contract to Sylvania Electronic Systems, a division of Sylvania Electric Products, Inc. It came into being in response to a high-priority request from the Special Air Warfare Center for new high reliability and light weight radio equipment for use in counter-guerilla operations and for training of native troops in Vietnam. In late January the pack was exhibited publicly for the first time at the IEEE International Convention at the New York Coliseum.
Telsfar II successfully launched A second Telstar experimental communications satellite was launched in May from Cape Canaveral. An important objective of the new Telstar will be to learn how to extend the useful life of communications satellites in space by avoiding or overcoming the effects of radiation, which twice disabled Telstar I's command circuit.
Telstar II was sent aloft for the American Telephone and Telegraph Co. by the National Aeronautics and Space Administration May 7, with the telephone company paying all costs for launching and tracking as it did for Telstar I.
An improved Delta rocket, more powerful than that used for Telstar I, was used to place Telstar i l in an orbit with a higher apogee (farthest distance from earth) where it will encounter less radiation. As with Telstar I, all technical information will be made available to NASA, and to the scientific community in general.
The satellite's elliptical orbit will take it from 575 miles at perigee (point nearest the earth) to 6,560 miles at apogee. Its predecessor, Telstar I, ranges in orbit from 592 miles to 3,531 miles, and takes 158 minutes to orbit the earth. Telstar II's orbit will take about 221 minutes.
The higher apogee of Telstar II will provide longer mutual visibility between the Bell System's ground station at An-dover, Maine, and ground stations in Europe. It will also give some mutual visibility between the Andover site and Japan, where ground stations are now under construction.
During its successful operation, Telstar I carried out all the experiments originally planned. More than 300 technical tests and over 400 demonstrations covered every aspect of transmission and proved the feasibility of communicating
via an active satellite. The demonstrations included multichannel telephony, telegraphy, data, telephoto and other facsimile transmissions. Transatlantic television was demonstrated 50 times, including five color telecasts.
The difficulties with Telstar I were diagnosed by engineers and scientists as ionization of gases in transistors in the command decoders. To prevent this in Telstar II, "evacuated" transistors will be used in one of the decoders. These are transistors in which the cap enclosure that surrounds the transistor has been pumped free of air and other gases and sealed under a vacuum. Without any gas in the cap enclosure there should be no ionization.
Both Telstar satellites, which are nearly identical, were developed and built by Bell Telephone Laboratories, the Bell System's research and development organization.
The electron detector of Telstar II has been changed so that it can measure electrons in an energy range from 750.000 to 2 million electron volts, instead of from 250,000 to 1 million electron volts as Telstar I did. This will make it possible to determine with greater precision the energy levels, number, and location of these higher energy electrons. Such knowledge will be helpful in designing an operating communications satellite system.
Telstar II's telemetry will report on some 118 items each minute when it is commanded "on" by a ground station. Telstar I made 112 such reports. The principle additions include measurements of the command circuit and a more precise check on pressure inside the satellite.
Telstar II will be capable of sending its telemetry reports on the same microwave frequency (4,080 mc) that is used for precision tracking of both Telstar satellitesa desirable accomplishment in a commercial satellite communications system.
Space communicaffon course is planned for June A short course on space communication for practicing engineers will be presented at the Long Island Graduate Center of the Polytechnic Institute of Brooklyn June 17-21.
Specific topics of communication theory to be presented include: Problems arising in the design of space communication systems: Channel characterization; Propagation and antennas; Characterization of noise; Low noise receivers using masers and parametric amplifiers; Tracking behavior of phase-locked loops; Theory of analog and digital modulation and detection; Coding and decoding of signals, and Communication systems and problems found in the Telestar, Relay, and Ranger experiments.
Four members of the Polytechnic Electrical Engineering faculty. Profs. D. T. Hess, D. L. Schilling, A. G. Schillinger, and M. Schwartz will present talks during the course, and there will be several speakers from the Bell Telephone Laboratories, Radio Corporation
of America, and Sylvania's Applied Research Laboratories.
The fee is $200, and attendance will be limited to 40 persons. A set of notes on the course will be issued. Further information may be obtained from Prof. Schwartz, or Prof. Schilling, Electrical Engineering Department, Polytechnic Institute of Brooklyn, 333 Jay St., Brooklyn 1, N. Y.
Ultrasonics fakes the ocean's tentperature Exploring the ocean's depths offers to the scientist as much challenge as exploring the environments of space. Oceanographers, aiming at an understanding of general conditions, are particularly interested in accurate temperature measurements, and for very practical reasons. For example, small changes in water temperature are known to affect the performance of sonar systems, the eyes and ears of submarines.
A new kind of "thermometer" for the ocean's depths involves ultrasonics sound waves too high in frequency to be audible to the human ear. Laboratory versions of the ultrasonic thermometer can pinpoint underwater temperatures to 5/100 degree F. The new system contains a transducer that changes electrical pulsations into mechanical vibrations of ultrasonic frequency. It can also reverse the process, converting the mechanical vibrations into electric pulses.
The transducer contains a small aluminum disk, about an inch in diameter, which has a natural frequency of vibration of about 40,000 vibrations per second. It is set in motion by a transistorized electronic circuit. Once in vibration, the disk precisely fixes the frequency at which the circuit oscillates, or produces electrical pulsations. Generated deep in the ocean, these pulses are sent along wires to the water's surface, where they are counted. The natural vibration rate
Sound waves far above the range of human hearing are used to take the ocean's temperature. Temperatures to 5/100 degree F can be recorded with
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of the disk changes with temperature. Therefore, temperatures are measured simply by observing the corresponding shift in frequency of the electrical oscillations.
Two wires, feeding d-c power to the instrument, extend down into the ocean depths. The pulses that measure the water temperature are carried upward over the same power leads. These leads can be relatively long without introducing errors into the readings. Accurate measurements up to depths of 10 miles appear feasible for future models.
A good conductor of heat, the aluminum transducer disk responds rapidly to changes in temperature and makes good thermal contact to the surrounding water. The transducer is mechanically rugged and has a high response to changes in temperature. Scientists at Westinghouse, J. H. Thompson and F. G. Geil, were the codevelopers of the instrument.
Advantages of the new device appear to be its ability to operate at extreme depths, its simplicity, and its characteristics of being a good thermal coupling between the ocean water and the metal transducer. Also, the temperature information is in digital form, and can be fed directly into a digital computer.
New color tube uses single gun A new color cathode-ray tube for television sets, that can be produced for substantially less than present color television tubes, has been patented bv D. M. Goodman of New York University.
The tube employs a single electron gun instead of using three guns, which is now standard practice in the industry. The new tube also dispenses with the mechanical "shadow mask," a selection device that cuts down the brightness of the projected picture.
The tube has a target screen consisting of repeating groups of vertical color strios and thin indexing strips, all deposited on the face of the tube. When bombarded by the scanning beam released from the single electron gun, the mdex strips give off short bursts of ultraviolet and X-ray index signals, which locate the position of the electron beam on the target screen. Attached to the electron gun are light pipes that pick up the index signals and send them through the neck of the tube to verv rapid gating circuits. These circuits sample the various video color signpjs, and then control the modulation of the electron beam to ensure registry of the color signals on the target screen.
The new tube does not employ the wire grids or, as mentioned, the apertured masks used bv the color cathode-ray tubes now in use. Instead, index strips and color strips on the fa:e plate of tfie tube form a unitary, nonvibrat'ng, sandwich assembly. The index strips operate at the same voltage as the color strips, requiring no additional high-voltage power at the target screen. Also, because the index signals are transmitted as electromagnetic radiation to the light pine members, additional high-voltage circuitry is not needed. This arrangement, which
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simplifies the target screen and index signal pick-up structures, makes the tube less expensive to produce. In addition, the new tube is better adapted to meet the broad range of environmental conditions likely to be imposed by industrial and military users.
The tube will be produced in the 21-inch 72-degree round envelope now available, and also in the 23-inch 90-degree rectangular envelope.
The tube, in addition to its obvious use in television receivers, is expected to have wide application to information display and electronic data presentation systems for civilian use and for military installations.
Further information can be obtained from D. M. Goodman, 3843 Debra Court, Seaford, N.Y.
U.S. contribution to IQSY is outlined Government scientists have released a detailed blueprint for their contribution to the International Years of the Quiet Sun (IQSY), a sequel to the International Geophysical Year (IGY) in the study of earth-sun relations. More than 50 nations are planning to collaborate in the new effort to understand how the explosive, million-degree solar atmosphere governs the environment of earth and the interplanetary medium.
The two-year program, called IQSY for phonetic reasons, is scheduled to begin Jan. 1, 1964, as the 11-year cycle of sunspot and solar flare activity approaches a low point.
A principal objective of IQSY will be to contrast the data to be gathered at solar minimum with that from the IGY in 1957-58, when solar activity was at the highest level since the beginning of systematic observations 200 years ago.
Plans for U.S. participation were prepared by the U.S. Committee for IQSY under the Geophysics Research Board of the National Academy of Sciences-National Research Council. The Committee
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represents the United States scientific community on the international body established by the Comit International Geophysique (CIG) of the International Council of Scientific Unions to coordinate the IQSY effort.
IQSY is to be a full-scale follow-up to the IGY, in its emphasis on the simultaneous world-wide recording of solar-dependent geophysical events and free exchange of data among nations.
While many IGY observations are to be repeated, to provide the first consistent set of geophysical bench marks for the high and low points of the solar cycle, the program also includes special experiments made possible by recent advances in techniques.
IQSY will concentrate on atmosphere and space phenomena directly affected by both the large periodic bursts of charged particles and associated magnetic fields escaping from the sun, and the confinu-ous background activity known as the "solar wind.*' IGY studies not bearing on the solar cycle have been omitted.
The goal of IQSY will be to obtain a portrait of the inn'i r s^lar svste^n at a time of relative quiet and, if possible, to isolate the atmospheric e f f e c t and distortions of the earth's magne field that result from a single solar event.
Consequently, the thre^ -^iterii established for IQSY project - r - : ( 1 ) St idies feasible only or best undertalc^n a* the time of minimum solar a^t'vi v: Studies of isolated solar events not complicated by the superposition in : if any different effects; and (3) Comparisons of data characterizing solar minimum activity with the solar maximum of the IGY.
fast breeder reactors to be studied Argonne National Laboratory, long a pioneer in the development of advanced reactors for the production of electric power, will begin design of a proposed Fast Reactor Test Facility (FARET) to
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