Los Alamos Announces Progress on Acoustic Heat Engines Discovery Astronauts Manufacture Metal Alloys in Experiments Funded by Gr

RESEARCH/RESEARCHERS Los Alamos Announces ing of Aligned Magnetic Composites;' was surveyed have their initial training in phys Progress on Acoustic sponsored by Grumman Corporation in ics. Another third began their careers in a Heat Engines an ongoing effort to reduce the expense of different field, but have taught physics reg producing high quality electronic materials ularly throughout their teaching career. The simplicity and reliability of a series of on earth. The remaining third can be classified as experimental acoustic heat engines have Small ingots of a MnBi compound were "draftees;' with training in other fields and led researchers at Los Alamos National melted. Each ingot was 80 mm long and 5 little previous experience in the teaching of Laboratory to begin seeking practical appli mm in diameter and weighed less than 20 physics. cations. g. The furnace they were melted in had The report concludes that three sets of Like their precursors, the Los Alamos heating elements programmed to move factors appear to have the greatest impact engines rely on two simple principles un along the length of the ingot at certain on the presence and robustness of physics derstood for centuries: the nature of how speeds. As the ingot was heated and programs in high school. They are: sound vibrates and the fact that changing cooled, tiny MnBi rods were formed as 1. school size, geographic location, and temperatures make materials expand and magnetic particles embedded within the urban or rural setting; contract. They convert heat to work or use composite material. The magnet's strength 2. the demographic character of the stu work to pump heat in a way similar to con is determined by the pattern, size, and dent body, especially its socioeconomic ventional refrigerators and steam turbines. composition of these rods. Rods formed in and racial composition; and But until recently, the engines tended to be a finer, more uniform pattern should pro 3. the level of commitment of the school complex mechanical machines requiring a duce a stronger magnet. administration to rigorous science educa lot of maintenance. The Los Alamos en Astronaut George Nelson, who led the tion, as measured by such variables as gines are much simpler in design, can be experiments, conducted similar proce years of science required for graduation, smaller than an adult's arm, and have no dures during earlier shuttle flights. A large level of funding provided for physics moving parts. body of data on MnBi has been produced, classes and laboratories, and level of ad According to Greg Swift, the Los Ala not only from the shuttle missions, but ministrative support perceived by teach mos researcher spearheading the project, from earth experiments and from short ers. the engines are little more than pieces of space flights aboard sounding rockets. For A number of factors conspire to keep metal or fiberglass tubing, resembling a further information contact Miriam Reid, physics enrollment from increasing, ac sawed-off piece of an organ pipe. At their Grumman Corporation, Bethpage, NY cording to the study. One is the scarcity of heart is a series of tiny parallel metal or 11714, telephone (516) 575-3999. Source: trained teachers. Another is low minimum glass plates that act as a heat exchanger. Electronic Materials Technology News, Octo graduation requirements in science (which One type of engine converts the heat to ber 1988, p. 3. in a large majority of states is still only one sound. Air passing over the hot end of the or two years) combined with the continued plates warms and expands, and then cools AIP/AAPT Survey Identifies tradition of teaching science: biology first, and contracts about 400 times per second chemistry second, physics last. Even when it reaches the other side. Following a Shortcomings, Needs of High School Physics Programs schools with formal programs to increase similar process, another engine converts enrollment-15% of the national total sound from a radio speaker into cool tem Only about 20% of U.S. high school stu appeared to be making little headway in peratures. dents enroll in physics classes-though attracting more students to physics. At its current stage of development, the nearly all of them have access to such pro Studies have shown that although most heat engine is not as powerful as gasoline grams. That is one finding in a recent re other countries retain a much smaller pro or electrically powered engines, but the ad port on secondary schools issued by the portion of their students in secondary vantages of simplicity and reliability might American Institute of Physics (AlP) in.col school, those who are retained face much make it ideal for powering satellites or for laboration with the American Association more rigorous standards than in the U.S. being the energy source behind submarir:e of Physics Teachers (AAPT). In many countries, science requirements sonar systems. It's this type of acoustic The study, Physics in the High Schools: typically extend across all years of the heat engine (except larger and using differ Findings from the 1986-87 Nationwide Survey grades equivalent to our high school, and ent materials) that Swift says might be of SecondanJ School Teachers of Physics, pro physics is one of the courses required of all come the grandfather of future vides detailed information on schools, and students. In fact, in many developed coun "cryo-coolers" for reliably cooling super on the training, experiences and attitudes tries a substantial proportion of students conductors. of the nearly 20,000 high-school-level phys take two years of physics, compared to just ics teachers. The study's objective was to one percent of U.S. high school students furnish findings that would be relevant to Discovery Astronauts who do so. Even more startling: perform the daily classroom needs of those teachers ance tests recently administered to this Manufacture Metal Alloys as well as to contribute to current discus small number of second-year or advanced in Experiments Funded sions. concerning the scientific literacy of placement physics students-the "cream by Grumman Corporation the nation's workplace and citizenry. of the crop" of this country's high school Among the findings: physics programs-showed that the Amer Hoping that space will provide eco • In the spring of 1987, 623,000 students icans placed near the bottom of the interna nomic advantages in the manufacture of were enrolled in high school physics in the tional ladder in their knowledge of certain expensive-to-produce metals and u.s. physics. alloys, astronauts aboard the space shuttle • Although 96% of all high school students Using the data acquired in this survey, Discovery in October melted ingots of attend schools where physics is available, AlP plans to issue future reports on spe manganese bismuth-a process which only about 20% of all high school gradu cific aspects of high school physics, such as produces stronger magnets. ates actually take physics. the status of women teachers, schools with The experiment, called "Orbital Process- • Approximately one-third of the teachers 8 MRS BUllETIN/JANUARY 1989 RESEARCH/RESEARCHERS heavy minority enrollments, and parochial laboratory to private industry when existing program to develop and market schools. Finally, in order to continue moni Argonne licensed it exclusively to Ameri high T, superconductors in usable form. toring changes in physics programs and can Superconductor Corp., Boston, Mas Under the license agreement, American among the ranks of teachers, a new round sachusetts. [See "Argonne and American Superconductor has exclusive rights to de of data collection is planned for 1989-90. Superconductor Sign" in this section.] velop and market a technology, developed Copies of the current survey are availa Gruen also helped develop SARISA by Argonne scientist Dieter Gruen [See ble from the AlP Division of Education and (surface analysis by resonance ionization "D.M. Gruen Named" in this section], Employment Statistics, 335 East 45th of sputtered atoms), a laser-based system that involves coating a wire with the right Street, New York, NY 10017-3483. For more that can detect surface impurities as small proportions of yttrium, barium, and cop information, contact AlP at (212) 661-9260, as 500 parts per trillion in the outer atomic per, then heating the wire in the presence ext. 326 or AAPT at (301) 345-4200. layer of semiconductors, metals, and metal of oxygen to oxidize the coating. The proc Editor's Note: See Postenninaries in this issue oxides. Unlike some other widely used de ess, on which a patent is pending, yields a fiJr some additional opinions 011 physics educa tection methods, it does almost no damage wire coated with yttrium-barium-copper tion. to a material's surface. oxide. Tests of this approach at Argonne Another invention Gruen helped to de have shown promise, but more work is Lewis, Argonne Sign velop is the excimer laser technique used in needed before the process yields a practical Agreement for Joint such intraocular surgery as repairing de superconducting wire. The licensing High Tc Effort tached retinas and lensectomies. Unlike agreement, which will allow American Su other lasers used inside the eye, the xenon perconductor to continue that work, is NASA's Lewis Research Center and chloride excimer laser cuts tissue with lit only the beginning of Argonne's potential Argonne National Laboratory have signed tle, if any, burning. It uses fiberoptics, to commercialize inventions in the area of an agreement to begin a joint research ef glasslike fibers 1 mm or smaller in diameter superconductivity, according to laboratory fort to develop high temperature super to deliver the laser beam to a precise point officials. conductivity (HTS) materials and inside the eyeball. The other agreement involves Argonne's technology.

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