by a relatively high sensitivity to aging, accelerated by sunlight and oxygen or ozone. This sensitivity may be decreased on earth by incorporation of antioxidents and ultraviolet absorbers. In space, the degradation of organic materials develops differently and does not depend on oxygen. The inorganic binders, on the other hand, are relatively inert to those weathering agents which disrupt organic binders. Organic paints usually display a high gloss, while inorganic paints are in­variably flat.

Ideally, only three surfaces need to be considered for adequate thermal control of a spacecraft: (1) a white paint (very high reflectance of the solar spectrum, and a very high omittance of infrared energy), (2) a black paint (very high solar absorption, very high infrared emit-tance), and (3) a polished metal surface (high solar reflectance and low infrared emittance).

By proper arrangements of these three surfaces, a space object may be con­trolled to cool to —100 F, or heat to 800 F.

The value of measurements lies in pre­dicting thermal behavior of a coated sur­face, and determining the extent of degradation during simulated solar il­lumination in vacuum. By measuring the spectral reflectance of a surface, a great amount of information may be obtained concerning its degradation.

Computer applicatiotis are broadening steadily The following items are some recent de­velopments in the field of computer tech­nology:

'TELEFUTE' SPEEDS RESERVATIONS The airline industry's international reser­vations system has expanded with the activization recently of Trans World Air­lines Teleflite system, built by the Tele-register Corp. The system is a develop­ment of the airline's earlier electronic reservations system which was introduced with the jet age. The new system will satisfy the airline's needs not only through the jet age but in the supersonic era ahead.

Up to this latest step, reservations han­dling has been a hybrid, combining elec­tronic speed in communications but slower manual bookkeeping. Teleflite does both in a matter of seconds.

The new reservations center at TWA's base operations building (hangar 12) at New York International Airport will maintain passenger records on all of the airline's flights in the United States and overseas. It replaces the reservations serv­ice center formerly located at Kansas City, and is linked directly to automated local availability processes (LAP) in Los Angeles, Chicago, and New York City, major airline centers.

Development of the Teleflite system is based on a building-block concept which has permitted a planned expansion pro­gram as needed. In this latest phase, bookings made overseas will be trans­mitted by teletype to the Teleflite com­puters at Idiewild which automatically read, process, and reply to the messages.

EDUCABLE COMPUTER In a long-term research project to "edu­cate" a computer to understand and re­spond to spoken messages, two Purdue LJniversity engineers claim results on a machine that performs slightly better than human beings do. Their findings were presented at a recent meeting of the Acoustical Society of America.

To grasp the meaning of spoken words in any accent or emotional stress, the computer's task is more difficult than that of the human ear because the computer cannot identify a whole word or sen­tence. It must, by its method of operat­ing, identify each sound individually. Therefore, in tests to compare the com­puter's with human judgments, the two investigators had test subjects listen to recorded vowel or consonant sounds alone. They reported that the sounds which people have particular diflRculty in identifying also confuse the machine; but the machine does better than humans in recognizing sounds which are not par­ticularly difficult.

With a mathematical measurement method, the investigators have analyzed the English language by means of the distinctive speech features established by linguists and phoneticians. (See February issue, page 151.) One of these is the tense-lax feature. For example, the vowel in "hat" is tense; in "head," lax; in "feel," it is tense; in "fill," lax. The tense-lax dis­tinction also holds true for consonants; for example, the initial consonant in "suit" is tense and that in "zoot" is lax.

In problems of dialects, and emotional and personality differences in speech, the speech of one person at a time is ana­lyzed; then the computer is fed enough information about his special characteris-tis to help it along. In the process the basic rules may be discovered that will work for every speaker. The investigation is supported by a U.S. Air Force grant.

TUNNEL DIODE IN OPERATING COMPUTER In an operating computer system, IBM has installed a tunnel diode that is an advanced electronic switch considered highly promising. The new memory is a small, high-speed register unit installed and tested as a specially engineered fea­ture in the IBM S T R E T C H computer used at the company's Poughkeepsie develop­ment laboratories.

The purpose of the register memory is to modify instructions to the computer at extremely high speeds. So far, applica­tion of the new memory has been re­stricted to the S T R E T C H where it can be studied further in an operating system. IBM does not plan to sell it in its pres­ent form in commercially available com­puters.

In the S T R E T C H system, the memory fetches and stores data in a cycle time of 600 nanoseconds (billionths of a sec­ond). In engineering tests, however, cycle times have reached 200 nanoseconds—5 million cycles a second—or at least three times the speed required by any existing computer, including the S T R E T C H .

In operation, the memory processes data at very high speeds. Its full capacity is 17 computer words of 74 bits (binary digits) each—equivalent to about 150 conventional letters or numbers. How­

ever, the 200-nanosecond cycle is so fast that the memory can process over 45 million letters or numbers a second— equivalent to 90 full-length novels.

The basic component in the IBM reg­ister memory is actually a tiny circuit containing a tunnel diode, a resistor, and an inductor, all encased in a plastic cell. A total of 1,258 of these cells are mounted on two ΛΥι- by 16-inch printed-circuit cards, which in turn are plugged directly into the computer. This design permits easy maintenance and affords high reliability.

INTEGRATED MAGNETIC TAPE TRANSPORTS Eight commercial magnetic tape trans­ports were delivered recently in two V-51 vans, for use in design tests of automatic data-processing systems at Fort Hua-chuca, Ariz. Each van is equipped with buffer devices to permit integration of the tape transports into the U.S. Army's F I E L D A T A family of tactical field com­puters.

The newly delivered tape transports are being used at the Army's electronic proving ground at Fort Huachuca, as part of the Command Control Informa­tion System-1970 (CCIS-70) Project pro­gram. The Project is coordinating efforts to employ computers in certain opera­tions of the Army in the field. In this instance, the Army has applied commer­cial off-the-shelf models of magnetic tape transports as mobile equipment for op­eration with more than one type of FIELDATA computer. The tape drives were operable within a few hours after being driven over the road from the plant at Wellesley, Mass., to Fort Huachuca.

Peace Corps ca / /s for many types of engineers The Peace Corps, entering its third year of operation, announces that one of the areas of major concentration is in engi­neering fields and that forthcoming proj­ects call for engineers to work in varied jobs, from classroom teaching on a uni­versity level to mapping out farm-to-market roads, planning rural electrifica­tion projects, working on water conser­vation programs, building bridges and aqueducts, and designing irrigation sys­tems. Host country requests received by the Peace Corps are doubling and tripling as the need for engineering skills devel­ops around the world from Malaya to Brazil.

"General Qualifications for engineering opportunities include a degree in engi­neering. Volunteers must be American citizens. They must have sound health, emotional stability, maturity, willingness to work with other people, initiative and a desire to serve. There is no upper age limit. Married couples are eligible if both can qualify for the same project and have no dependents under 18."

The quoted paragraph is contained in a special brochure, "Engineering In the Peace Corps," geared to professional en­gineers, that may be obtained by writing to Jules Pagano, Director, Professional and Technical Division Office of Public Affairs, Peace Corps, Washington 25, D.C.

536 E L E C T R I C A L E N G I N E E R I N G · A U G U S T 1963