REPORT FOR ANALYTICAL
CHEMISTS
The Long Look at National Research Needs
Continued progress in space, missile, and nuclear technology is hampered by lack of fundamental d a t a on hot gases, plasma, and high temperature; high purity and precisely characterized materials; and high pressure and synthetic materials. With its increased budget, National Bureau of Standards is e x p a n d ing its research on these new frontiers Allen V. Astin, 55-year old Director of the National Bureau of Standards, is shown inspecting equipment used by NBS to provide knowledge of the mechanism of combustion and to develop ways to measure temperature of flames that are too hot for ordinary thermometers. Dr. Astin, who prepared this article for ANALYTICAL CHEMISTRY, has been
associated with NBS since 1932. A native of Utah, he received his B.S. degree from the University of Utah in 1925, and his M.S. and P h D . degrees in physics from New York University in 1926 and 1928, respectively. Prior to joining the NBS, he was a chemical analyst for American Smelting and Refining Co., a Research Council Fellow at Johns Hopkins University, and a research associate with the Utilities Research Commission, Inc. At NBS, he worked for 8 years in the Heat and Power and Electricity Divisions studying ignition, electronic, and electrical problems, and associated instrumentation. From 1940 to 1950 he worked in the Ordnance Development Division particularly in development of the proximity fuse. During this period he was also in the European Theater of Operations in connection with proximity fuse problems. In 1950, Dr. Astin became associate director and headed up programs of the Ordnance Development Missile, Electricity, and Electronics Divisions and the Office of Basic Instrumentation. He became director of NBS in 1952, the position he now holds. He has received many honors and awards for his scientific attainments.
i n the past several years we have seen a substantial expansion of the nation's research and development effort. In this context there immediately comes to mind the growth in advanced weapons planning under the cognizance of the Advanced Research Projects Agency, the exploration of space under the new National Aeronautics and Space Agency, and the increasing emphasis on nuclear technology under the Atomic Energy Commission. Space, rockets, satellites, missiles, reactors, accelerators, and a number of other new devices and fields of novel investigation have attracted the attention of scientists and laymen. So much is this the case that we may overlook some important research programs which are also necessary to the continuing progress of science and technology in general and to the specifically accelerated research activities already mentioned.
This brings me to the role of the National Bureau of Standards in federal science and to the important, though often misunderstood, responsibilities assigned to it. Because it is responsible for the development and refinement of physical standards and for the advancement of techniques of measurement, the National Bureau of Standards and its programs lie close to the heart of science. Such an assertion is not intended to derogate the contributions of other research agencies, but to emphasize the critical relationship of measurement to expanding experimental programs. None of the important programs already mentioned could make substantive advances without supporting improvements in the tools used for measurement, observation, and data collection. For this reason (and for a number of others not pertinent to this line of argument), the Bureau was established as, and VOL. 31, NO. 10, OCTOBER 1959 ·
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The controlled-clearance piston gage (right) is used as a primary standard of high pressure. The instrument operates in different pressure ranges (up to 120,000 p.s.i.) depending on the piston-cylinder combination used. The device on the platform (left) is being calibrated against the primary standard
A photoelectric pyrometer is used to measure temperature of a lamp (right). This instrument was designed and built at NBS for temperatures above 1000° C. The amplifier (top) feeds output to a recorder (rear). This pyrometer eliminates visual judgements of brightness and shows a substantial gain in precision over disappearing-filament pyrometers
has remained, a major research laboratory of the Government, with a broad and basic research program. Perhaps it would be useful first to describe, as an example, the importance of advanced measurement to one of the fields mentioned. Anyone familiar with some of the major problems of space exploration will readily agree, I believe, that the obstacles to routine successful space flight pre chiefly those resulting from inadequate measurement and control techniques and a lack of information on the properties of newly important materials. The broad theories of space exploration, I think, are well developed. The mathematical and physical concepts have been fairly well worked out. W h a t seems to be lacking, in an ultimate sense, is the precise control in the production of the thousands of components necessary to these exploratory instruments, maintenance of precision during assembly, and further control during operation. This is a most difficult problem. And, again in an ultimate sense, this problem 22 A
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rests with the National Bureau of Standards. It is the responsibility of the Bureau to provide the standards necessary to meet these new problems and requirements. Let us follow the example a little further. In addition to providing the basis for measurements of very high precision, the Bureau is also involved in providing the understanding of the behavior and properties of basic materials. This responsibility for characterizing materials stems from the Bureau's interest in measurement, and its statutory responsibility to determine those properties of materials that are of great importance to science and industry and are not available of sufficient accuracy elsewhere. In the present situation, it is especially important that materials be studied, cataloged, and characterized as fully as possible so that an abundant storehouse of materials information is available to scientists and engineers seeking to develop the devices capable of performing at the new speeds, temperatures, and conditions to be met in outer space.
Today research and technology seem to be going hand in hand so that there is more and more a "coming together" of the two. The two, in this and a number of other situations, are interdependent. The production of highly precise instruments out of highly characterized materials will be an intrinsic element of future research and development. In this respect, the role of measurement and instrumentation takes on added importance. I mention this to point up the link which measurement provides between research and technology. The measurement system which serves both must be both consistent and precise to the degree required. I have some concern about this, having found evidence that this relationship was not adequately appreciated by American scientists, and in some cases even less by planners involved in future instrumentation and the use of new materials in production. My concern is compounded by my own awareness that Soviet policies are oriented towards strengthening the role of standards and measurement in
REPORT FOR ANALYTICAL CHEMISTS
Crystal growth at 1400° C. is observed through a microscope. A high-intensity illuminator reduces the relative intensity of the light emitted by the specimen. Manual adjustment of the automatic temperature control, sensitive to a fraction of a degree, allows convenient control of the number and perfection of crystals formed. This instrument is illustrated on the cover
The equipment shown is used for low-temperature calorimetry studies at NBS. It automatically controls the temperature of a sample material to approximately 0.002° C. These studies provide molecular and thermodynamic data essential for development of new materials needed in the Space Age
Russian science and technology. It seems apparent, if one gives any credence to Russian claims, that the U.S.S.R. is establishing a close link between science and technology through measurement, that the U.S.S.R. has achieved considerable success in certain areas of the measurement sciences, and that standardization problems are a high-level responsibility within the Soviet scientific and political hierarchy. All this means that any future expansion or acceleration of America's research and development effort must carry with it proportionate opportunities for growth in the basic sciences and in the fundamental areas of measurement and physical standards. Fortunately, this year the Congress has provided the funds and the opportunity to initiate a number of selected programs of considerable urgency. The Bureau's plans may be described in three important research areas: hot gases, plasma, and high temperature; high purity and precisely characterized materials; and high pressure and synthetic materials.
Hot Gases, Plasma, and High Temperature
Last year the Bureau presented to the Congress an urgent request for funds to undertake a broad and accelerated program of research on the measurement of very high temperatures. The basis of the request was the growing need of science and industry for data and measurement techniques. The urgency was underscored by the apparent achievements of the Russians in this area. As a result of the Bureau's request, the Congress earmarked funds for beginning an expanded program of basic studies at NBS in high temperature research. This year, in reporting on the year's work to the Congress, I was able to note that marked progress had been made in devising and developing equipment for measuring the properties of materials at very high temperatures and that new work in the field of hot gases and plasma physics and chemistry had been initiated. More specifically, at the end of the first year of this new program, the Bureau was able to report the follow-
A diamond (lower right) is used at NBS as a highpressure cell. A small sample of the material to be studied is placed in a narrow hole bored through the diamond and compressed between steel pistons. Application of a force of 80 pounds to the pistons will generate a pressure of 450,000 p.s.i. in the diamond. Changes in the sample are detected by the way it transmits infrared light. The mount (below) which holds the diamond, has 4 "curtains" to limit this infrared beam. The position of each curtain is adjusted by tuning the projecting rod. This mount fits into the depression at the base of the press. The apparatus is being used for studies at room temperature. Later it will be used to study effects of combined high temperature and pressure VOL. 3 1 , NO. 10, OCTOBER 1959
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REPORT FOR ANALYTICAL CHEMISTS
Prototype of NBS instrument for measuring viscosity of liquid inorganic oxides at temperatures up to 2000° C. and higher. This model was used to demonstrsie the feasibility of the method for the range of viscosities anticipated. Liquid is held in a closed cup suspended inside the cylindrical housing (left) to form a torsion pendulum. Viscosity is determined from damping effect of liquid on torsional vibrations. Scientist follows vibrations by directing telescope to mirror attached to pendulum; mirror reflects scale on wall
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The plasma jet device developed by NBS is used for spectrochemical analysis of solutions. Temperatures up to 8000° C. can be obtained for spectral excitation of elements vaporized from a solution. Standard solutions are used to compare the relative emission intensities in making quantitative determinations. Results show a 2% coefficient of variation
ing: a high current arc capable of producing controlled temperatures has been constructed as a temperature source; the range over which optical pyrometers can be calibrated was extended from 2400° to 3800° C , permitting more accurate calibrations of high temperature devices used in rocket and missile developments; the development of standards of measurement for use in high temperature operations in the field was initiated and suitable equipment for such measurement was being planned; equipment was improved to permit data to be obtained on the elastic constants of inorganic solids at temperatures up to 2000° C. ; and work was initiated to devise experimental methods for simulating plasmas of ionized gases on a laboratory scale. The Congress has this year provided funds to continue the programs started last year and to undertake additional work in the field. This year, and for several years more, the Bureau will undertake a
thorough study of the properties of very hot gases. In addition, NBS is seeking to extend its high temperature calibration capabilities so as to achieve a 10-fold increase in accuracy over t h a t of current methods. Furthermore, we hope to add substantially to the data available on elastic constants, heat capacity of refractory materials, and the nature of high-temperature reactions. Although the Bureau now is in a much more favorable position to. undertake high-temperature investigations, our efforts are only beginning to meet the needs in many areas. For example, £he Bureau's program of research at ultra-high temperatures is in its infancy, and it will take several years before information adequate to the requirements will be forthcoming from these programs. High Purity and Precisely Characterized Materials
One of the serious problems confronting theorists and experimental-
A six time reduction in size has been attained by NBS with its new compact wedgetype high pressure apparatus. This apparatus housed in an eight-inch diameter cylinder permits production of pressures in excess of 100,000 atmospheres with a conventional hydraulic press. The apparatus shown permits: studies of fundamental properties of materials at high pressures, establishment of "fixed points" on the pressure scale, and development of improved pressure measurement techniques. A larger model is being built. In the photo, the top anvil and the cover have been removed to show the »/2 inch pyrophyllite tetrahedron in which the sample was placed. The gasket (light area adjacent to tetrahedron) has been extruded under pressure. The anvils are electrically insulated and lubricated with Teflon sheets and electrical leads brought out of the sample
ists concerned with the development of materials for special or novel applications is the lack of basic data on the intrinsic properties of simple substances. To collect such data properly, we should begin with materials in their purest form. This will require a major research effort, but when we have attained first the skills for achieving high purities and then when wc have produced these pure materials in sufficient quantity for extensive basic investigation, we will be in a position to make a comprehensive compilation of data on properties. Pure materials will allow an intensive examination of atomic structures under controlled conditions which will permit the prediction of materials behavior in novel situations. T o d a y we can make such predictions only under strongly limiting conditions. We know very little about the effect of impurities
REPORT
on materials. W e need to know much more about two types of impurities: impurities of mass (foreign atoms in a substance) and impurities of nonmass (dislocations in atomic structure). To do this, we have to get away from bulk observations of thé properties of materials and get to the atomic heart of very pure single crystals. In the past, the Bureau has achieved high purities of gold, copper, gallium, silver, and a number of others. Now the requirements have increased greatly. T o day we must achieve purities which will challenge the capabilities of our most creative experimental chemists and physicists. N B S is expecting, this year, to initiate a much expanded program in the field of pure substances. T h e principal emphasis of this expanded program will be on the development of techniques for achieving high purity and for characterizing materials precisely. With the dissemination of such techniques to the materials research laboratories of the nation, there will exist the basis for an enlarged national program of basic research on the properties of m a t e rials. In support of this emphasis on methodology, the NBS program will have three other aspects: to obtain pure materials for use by scientists and materials research specialists throughout the country; to develop highly characterized
materials for use by scientists and materials specialists as reference tools ; and to provide materials data arising from the studies of these substances and to contribute t o the understanding of the behavior of these highly characterized materials under static and dynamic conditions. High Pressure and Synthetic Materials Somewhat similar to the situation in the high temperature field there has been a growing dependence on high pressure phenomena for a number of important technological applications. I t has been demonstrated, in a few instances, t h a t very high pressures can be used to produce materials nonexistent or nonabundant in nature. In some cases, the new materials have proved superior to anything naturally developed for such characteristics as hardness and resistance to chemical attack. I t seems to be the considered opinion of many t h a t the "super pressures" offer very great promise of fulfilling some of the severest requirements for new materials to be used in specialized military and industrial application. The Bureau's work in this field has been described as an "unimpressive fraction of what should be done at N B S . " Ί here is a pressing need for a well defined pressure scale, stand ard measurement techniques, and
the precise determination of the basic properties of materials at various regions on the pressure scale. At the present time, NBS has a limited capability for meas urements up to about 200,000 pounds per square inch. There is a need to improve this capability at this and lower pressures and to ex tend it to about 1,000,000 pounds per square inch. This year the Bureau will initiate a program aimed at establishing a pressure scale using at least three fixed pressure points representing precisely determined physical con stants; developing safety data for high-pressure instruments; provid ing information on high-pressure techniques; relating high-pressure research and techniques to prob lems in thermodynamics; and de veloping improved measurement techniques and instrumentation. The above three fields of research are by no means a complete listing of what will receive special atten tion during this year. Even less so are they intended to describe all of the scientific areas in need of ex panded research emphasis. They do represent the Bui'eau's judgment of some of the most urgent needs and require immediate expansion, and they do illustrate the impor tance of Bureau research programs to the growth of science.
