Applications: Used to determine enthalpies of reaction at or near room temperature, for the purpose of obtaining enthalpies of formation, enthalpies of solution, and related thermodynamic properties of sub stances. Availability: Because of the complexity of the instrumentation and the procedures of operation, use of the facility is limited to qualified members of the NBS staff scientists, after specific training of perhaps two months. The facility may be used indirectly through cooperative or contractual research agree ments. Literature: Prosen, E. J., and Kilday, M. V., J. Res. Nat. Bur. Stand. (U.S.) 77A, 179 (1974). Contact: Dr. G. T. Armstrong, Chief of Thermochemistry Section, Chemistry Building, Room B350, Phone 301-921-2131. ROTATING PLATINUM-LINED, Capability: Solid or liquid samples are reacted with oxygen at 30 atm pressure in a 100 cm3 combustion bomb. The type of sample is limited only in that the products of the reaction must not be any chemical species that attacks platinum. A uniform concentration of aqueous products is assured by continuous rotation of the calorimeter. Amounts of sample are normally such as to cause 2500 J to be liberated as heat in the reaction. Under optimum conditions, the energy of reaction can be determined between 298 K and 323 K with a precision of better than 0.005%. Calorimeter temperatures are measured potentiometrically with a platinum resistance thermometer as the sensor. The adiabatic shield temperature is controlled automatically to eliminate heat transfer to the calorimeter from its environment. Determination of the amount and products of reaction can be determined by measurement of the amount of CO2 gas formed, and by analysis of aqueous solution constit uents. Applications: Used to determine enthalpies of reaction at or near room temperature, for the purpose of obtaining enthalpies of formation, enthalpies of solution, and related thermodynamic properties of substances. Availability: Because of the complexity of the instrumention and the procedures of operation, use of this facility is limited to qualified members of the NBS staff or other scientists, after specific training of perhaps two months. The facility may be used indirectly through cooperative or contractual research agree ments. Contact: Dr. G. T. Armstrong, Chief of Thermochemistry Section, Chemistry Building, Room B350, Phone 301-921-2131. COMPUTER CENTRAL COMPUTER FACILITIES The NBS Central Computer Facilities are available on a fee-for-service basis to support Government programs. In addition to Federal agencies, certain state and local government agencies, non-profit organizations, universities and private organizations, may qualify for use of the facilities. Service can be provided to non-Federal agencies on joint projects or for work that cannot be done effectively in the private sector. Arrangements can often be made to process work through remote terminals. Facility Overview: The main computer in the NBS Central Facility is a UNIVAC 1108. The present operating system, EXEC 8, is a general purpose executive designed to operate in a multiprogramming environment which provides for a variety of user options. Access to the main computer is provided to both onsite users and those at remote terminals connected via telecommunications. Software support includes FORTRAN, COBOL, ALGOL, FLOWGEN (Automatic Flow Chart Generation), XBASIC, and OMNITAB (a computer language developed at NBS for statistical and numerical analysis). Univac 1108: The UNIVAC 1108 includes 262,144 thirty-six-bit words of 750 nanosecond core memory. Auxiliary high-speed (1,440,000 characters per second) drum storage of approximately 25-million characters capacity provides for efficient workload control and swapping of executive program files. Other drum storage of approximately 925-million characters (FASTRAND mode) provides the needed capacity for on-line storage of application programs and data files. In addition, the system configuration includes eight seven-track VIII-C Tape Drives (200, 556, 800 CPI), two nine-track VIII-C Tape Drives (800 CPI), one 758 high-speed Printer, one 1403 off-line Printer, one 1004 Reader/Printer, one 1004 Card Punch, one highspeed Card Punch (300 CPM), and one high-speed Card Reader (900 CPM). Graphics Facilities: The Central Computer Facility provides off-line plotting on a CalComp 763 ZipMode Digital Plotter, Computer Ouput to Microfilm (or hard copy) using a Stromberg-Carlson 4020, and extended character printing. A Graphical Display Sys ELECTRICAL tem software package is available which permits op- FACILITIES tical output to a variety of display devices including the CalComp Plotter, the S-C 4020 Microfilm Recorder, or the Line Printer. Capacity to Handle Scientific Documents: An extended character input/output subsystem, presently operating off-line to the 1108, permits users to take full advantage of the information interchange facilities of the American National Standard Code for Information Interchange (ASCII). This provides character printing sufficient to handle scientific documents at the normal level of complexity in notation, including half-line spacing for superscripts and subscripts, a repertory of Greek alphabetic characters and an assortment of special signs and symbols. Offline paper tape facilities exist for entering ASCII punched paper tape as data via a 300 CPS optical scan paper tape reader. Applications and Services: While the primary use of the central computer facility is as a laboratory tool for the technical staff of NBS and other agencies, an increasing level of support is provided to a variety of administrative and other data processing applications. A consultant is available during working hours by phone or in the computer center for advice on details of system operation and problems owing to system and program interaction. New system development is frequently done for problem areas of general utility. Periodic training sessions are held to acquaint users with various system capabilities (both hardware and software). Literature: Various manuals are available to NBS Use of Computer Facilities: Charges for the various Interested parties may contact Mr. R. A. Palladino, NON-MAGNETIC FACILITY. The probe shown in the fore ground travels along the axis of the 1000-turn precis solenoid to locate the axial position of each turn of wire and to compare the relative area enclosed by each turn This measurement allows calculation of the magnetic fie produced by a known current. AUTOMATIC NETWORK ANALYZER Provides computer controlled rf stimulus for the cal bration and measurement of passive quantities such as impedance, reflection coefficient, and attenuation and active quantities such as power and voltage. This is a commercially available item which has been mod ified into a special high accuracy system by NBS personnel. Capability: The automatic network analyzer provides for discrete frequencies in the range of 0.1 to 18 GHz as an rf stimulus, applies these signals to the device under test, measures their characteristics, mathematically manipulates the data if necessary and outputs the data. The data output is available as a tabulation on a teletype or high-speed printer, a plot or diagram on an electrostatic plotter, or may be viewed as polar or rectangular plots on an oscilloscope. The measured data is in complex form and may be reflection coefficient, impedance, renormalized impedance, VSWR, attenuation, gain, or phase angle for passive quantities. Data output is in watts, volts, or fractional (decimal) parts thereof for active quantities. The connector types for connection to the automatic network analyzer may be in coaxial type such as APC-7, GR-900, type "N" male or female, and in all the waveguide sizes used in the above frequency range. These capabilities can be adjusted for either normal laboratory precision or for high accuracy standards and calibration type measurements. The NBS add-on system for high accuracy measurements and calibrations is presently undergoing evaluation. Applications: The automatic network analyzer is intended for design, measurement, and calibration of rf and microwave components such as terminations, attenuators, thermistor mounts, crystal detectors, FIM receivers, antennas, filters, amplifiers, transistors, etc. As described previously these may be of coaxial or waveguide type usage devices. Availability: To any qualified NBS research worker, after an initial training period with supervisor. In appropriate instances individual research workers from other Federal organizations can gain access to the facility. Contact: W. E. Little, Program Chief, Automatic Network Analyzer Applications, Radio Building, Room 4633, NBS Boulder, Colo. 80302, Phone 303-499-1000 ext. 3658. ELECTRO-OPTICAL FIELD MAPPING SYSTEMS State-of-the-art electrical and electro-optical measurement techniques are employed for measurement of high voltages, and for observation and probeless fringe-pattern mapping of high-intensity electric fields in insulating dielectrics. Apparatus allows operation under microsecond pulsed, and either steadystate direct or alternating voltages. Unique advantages afforded by the recently developed NBS electro-optical systems include their freedom from electro magnetic interference errors and their provision for direct visual observations (analogous to those used conventionally in photoelastic studies of mechanical stress) of electrical stress distributions. Capability, Operating Ranges, and Accuracy: 1) Pulsed Operation: peak voltages from 20 to 300 kV, risetimes of 0.5 to 2.0μs with durations up to 10μs, repetition rates to 4 pulses per minute, measurement accuracy within ±1%. 2) DC Operation: from 0 to 100 kV, measurement accuracy 0.01%. 3) AC Operation: from 0 to 50 kV rms, from 40 to 200 Hz, measurement accuracy to 0.01%. Programs are available for automatic reduction and analysis of data, using NBS computer facility. Applications: For calibration of HV pulse-measuring devices; for design studies with visualization of both steady-state and dynamic electrical stress distributions in selected insulating dielectrics; for visualization of the effects of space charge, suspended particles, dissolved ionic impurities and electrode composition, polish and geometry on electrical conduction in selected insulating liquids; for mapping of electric field distribution around immersed solid insulator models; for measurement of Kerr electro-optical coefficients of liquids; for dynamic and steady-state electrical breakdown studies in selected dielectrics; etc. Availability: To qualified U.S. research workers. from industry, government, and academic communities in cooperation with NBS supervisor. Scheduling is required to avoid conflict with in-house NBS research, calibration and testing programs. structure (ground level plus two stories) constructed of non-magnetic materials and contains a minimum amount of electrically conducting materials. The building contains four isolation piers, one serving the ground floor and three serving the second floor level. A service building 300 ft from the non-magnetic building provides the general laboratory equipment and support. Experiments in the non-magnetic building can be controlled and monitored from the service building. Capability: Typical earth's magnetic field gradients are 10 nT m in the vertical direction and 3 nT⚫m-1 in the horizontal direction. Three-dimensional Helmholtz coils are available for cancelling the earth's magnetic field. Variations in the earth's field can be reduced by servo-ing to a magnetometer system in the magnetometer station located nearby. A precision solenoid is available to provide a magnetic field of 1.2 X 10 T which is uniform within a 4-cm diameter sphere and accurate to about 0.5 ppm in terms of the NBS electrical standards. Equipment for automation and data acquisition is available. Applications: The facilities of the non-magnetic building provide an environment where accurately known uniform magnetic fields can be applied to an experiment or where the earth's magnetic field strength and variations can be reduced a known amount. Currently the gyromagnetic ratio of the proton and the absolute ampere experiments are housed there. Availability: The facility is available, when neither of the above two experiments are in active operation, for a compatible experiment which will not compromise the non-magnetic environment. Literature: [1] R. L. Driscoll and P. T. Olsen, The Review of Scientific Instruments, Vol. 42, No. 10, 1427 [2] R. L. Driscoll and P. T. Olsen, Proc. of the International Conf. on Precision Measurement and Fundamental Constants, NBS Special Publ. 343, 117 (1970). [3] B. N. Taylor, D. N. Langenberg, and W. H. Parker, Scientific American, Vol. 223, No. 4, 62 (1970). Contact: Dr. E. R. Williams, Absolute Electrical Measurements Section, Non-Magnetic Building, Phone 301-921-2007. REACTANCE BRIDGE FOR POWER LOSS A typical high voltage inductor or shunt reactor on a power transmission line has a reactive power rang of 100 megavolt-amperes and a power loss of abu 220 kilowatts. Thus the power losses are of econom significance, but it is difficult if not impossible t measure them by conventional wattmeter methoc because of the low power factor, i.e. the presence or very large reactive or circulating power. The shu reactors are used to "tune out" the capacitances o transmission lines. A reactance bridge has been de veloped and constructed which in conjunction wh readily available high-voltage standard capacitors can measure accurately such losses. Inductance and capac itance can also be measured. The instrument is de signed for measurement of devices rated at moderate to extra high voltages-several hundred volts to o megavolt. Capability: The instrument can be used at either the NBS or a commercially available high voltage labora tory. The voltage and power ranges depend princ pally on the capability of the power supply in the laboratory-for the NBS laboratory these are 220 200 kVA. Some commercial laboratories have capa bilities of the order of 1 MV and 100 MVA. When used in conjunction with a typical high voltage stand ard capacitor having a capacitance value of 100 p the inductance range of the specimen is from 0.12 to 600 H; the range for capacitors is from 100 pf 50μF. The power losses can be measured to abou one-percent accuracy; the inductance and capac tance to about 0.01 percent to 0.1 percent accurac Applications: Primarily power loss measurements of large capacitors and inductors such as energy storage and power factor correction capacitors, high vola shunt reactors (inductors); also impedance measure ments of the same. Availability: To any qualified NBS research worker or group. The High Voltage Measurements Section w provide an operator for the instrument and high voltage power supplies. The use of the instrument is also available to outs de groups in the form of calibration and test services Literature: NBS Tech. News Bull., April 1973, Vol 5 No. 4, page 91. Contact: Oskars Petersons, Chief of High Voltage B344, Phone: 301-921-3121. ELECTRON MICROSCOPES tion using dendrites of aluminum-tungsten; identification of material in micrometeoritic lunar craters; distinguishing chrysotile from termolite; qualitative chemical analysis of microscopic particles; effect of polishing on dental materials; rusting through pinholes in enameled steel; bonding and defects in microcircuitry wafers; hydrogel coating on aortic catheters; wear of currency papers; sharpness of tungsten field-emitter tip. Availability: To any qualified NBS research worker, after an initial training period. Over 30 NBS scientists have become competent operators. In appropriate instances individual research workers from other Federal organizations can gain access to the facility. Literature: NBS Tech. News Bull., March 1972, Vol. 56, No. 3, pages 60-63. Contact: Dr. Arthur W. Ruff, Jr., Chief of Lattice Defects and Microstructures Section, Materials Building, Room B118, Phone 301-921-2991. With resolution and depth of focus well beyond that of optical microscopes, this device uses a fine electron-beam probe to explore the minutiae of surface structure of materials such as lunar rocks, bridge structure fractures, microelectronic circuits, and dental restorations. For rough specimens, stereo-pair photography permits three-dimensional examination. Selected area electron channelling patterns can be obtained, and divergent-beam x-ray (Kossel) patterns can be prepared for use in determining local stressstrain configurations. Capability: Replica or actual specimen up to 2.5 cm diameter and 1 cm thick. Resolution of 25nm, and maximum magnification of 100,000x. Electron beam of about 10 nm (100Å) diameter is driven across specimen, while secondary electrons, backscattered electrons, and x-rays are each detected and amplified to modify the brightness of a CRT raster. A data acquisition system and data reduction programs are available. Applications: Behavior of grain boundaries in embrittled copper-palladium welds; checking of resolu TRANSMISSION ELECTRON MICROSCOPE, 200 kV This instrument allows high resolution examination of surface replicas and actual, thin-foil specimens of metals, ceramics, and polymers. Analysis of microstructure and lattice defects in crystalline materials can be made by electron diffraction contrast and selected area electron diffraction. Compared to conventional transmission electron microscopes (100 kV), specimens which are 70% thicker can be examined. This facilitates specimen preparation, increases foil rigidity, and reduces surface effects. Capability: Accelerating voltages of 50, 100, 150, and 200 kV. Selected area electron diffraction and electromagnetic beam tilting (±3°) for dark field imaging. Side entry goniometer stage with: double-tilt (X = +60°, Y±45°), rotation (360°)-tilt (60°), and heating (to 1000° C)-tilt specimen holders for specimens up to 3.05 mm in diameter. Resolution (line) of 0.7 nm (7 Å) and maximum magnification of 150,000x. Data recorded on 34 X 4 inch glass photographic plates. Applications: Examination of the surface regions of various ceramic materials after abrasive and smoothsliding wear; analysis of deformation and fracture mechanisms in ceramics as a function of temperature; analysis of cracks and crack healing processes in ceramics; microstructure characterization of cemented carbides; determination of stacking fault |