National Institute Technology

For an introduction to current research in alkali-atom BEC see tire special issue on BEC in the Journal of Research of the National Institute of Standards and Technology ... 

WebBook National Institute of Standards and Technology thermochem., spectra numeric 22 300 substances online http //ivebboo- ik.nist.gov... 

Several excellent print collections of spectra are available but are beyond the budgets of most col lege libraries Fortunately vast numbers of NMR IR and mass spectra are freely accessible via the Spectral Data Base System (SDBS) maintained by the Japanese National Institute of Advanced Industrial Science and Technology at... 

NIST, National Institute for Science and Technology (formerly the National Bureau of Standards, U.S.). t A.P.I. is the American Petroleum Institute. 

Analysis sheet for Simulated Rainwater (SRM 2694a). Adapted from NIST Special Publication 250 Standard Reference Materials Catalog 1995-96, p. 54 U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology. 

The accuracy of a spectrophotometer can be checked by measuring absorbances for a series of standard dichromate solutions that can be obtained in sealed cuvettes from the National institute of Standards and Technology. Absorbances are measured at 257 nm and compared with the accepted values. The results obtained when testing a newly purchased spectrophotometer are shown here. Determine if the tested spectrophotometer is accurate at a = 0.05. 

Calibrating the electrode presents a third complication since a standard with an accurately known activity for H+ needs to be used. Unfortunately, it is not possible to calculate rigorously the activity of a single ion. For this reason pH electrodes are calibrated using a standard buffer whose composition is chosen such that the defined pH is as close as possible to that given by equation 11.18. Table 11.6 gives pH values for several primary standard buffer solutions accepted by the National Institute of Standards and Technology. 

Analysis of Standards The analysis of a standard containing a known concentration of analyte also can be used to monitor a system s state of statistical control. Ideally, a standard reference material (SRM) should be used, provided that the matrix of the SRM is similar to that of the samples being analyzed. A variety of appropriate SRMs are available from the National Institute of Standards and Technology (NIST). If a suitable SRM is not available, then an independently prepared synthetic sample can be used if it is prepared from reagents of known purity. At a minimum, a standardization of the method is verified by periodically analyzing one of the calibration standards. In all cases, the analyte s experimentally determined concentration in the standard must fall within predetermined limits if the system is to be considered under statistical control. 

Because variations in accurate isotope ratio measurements typically concern only a few parts per 1000 by mass and there are no universal absolute ratios, it is necessary to define some standards. For this purpose, samples of standard substances are produced and made available at two major centers IAEA (International Atomic Energy Authority, U.K.) and NIST (National Institute for Standards and Technology, U.S.). Standards from other sources are also available. These primary standards can be used as such, or alternative standards can be employed if the primary ones are not available. However, any alternative standards need to be related accurately to the primary ones (see formulae below). For example, the material PDB (PeeDee belemnite), used particularly as a standard for the ratio of isotopes, is no longer readily available, and a new standard, VPDB,... 

Standard substances are available from such agencies as the International Atomic Energy Authority (U.K.) and the National Institute for Standards and Technology (U.S.). 

PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) The national institute of standards and technology... 

Handbook 44, Specifications, Tolerances, and Other Technical Requirements Tor Weighing and Measuring Devices, National Institute of Standards and Technology, Gaithersburg, Md., 1996. 

There are no estabHshed specifications for the standard reference samples used in general chemical analysis. Many such substances, however, are analyzed and certified by the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards (NBS). Specific reference standards are required for many of the analyses included in the USP and NE standards for dmgs. 

National Institute of Standards and Technology (NIST). The NIST is the source of many of the standards used in chemical and physical analyses in the United States and throughout the world. The standards prepared and distributed by the NIST are used to caUbrate measurement systems and to provide a central basis for uniformity and accuracy of measurement. At present, over 1200 Standard Reference Materials (SRMs) are available and are described by the NIST (15). Included are many steels, nonferrous alloys, high purity metals, primary standards for use in volumetric analysis, microchemical standards, clinical laboratory standards, biological material certified for trace elements, environmental standards, trace element standards, ion-activity standards (for pH and ion-selective electrodes), freezing and melting point standards, colorimetry standards, optical standards, radioactivity standards, particle-size standards, and density standards. Certificates are issued with the standard reference materials showing values for the parameters that have been determined. 

Research sponsored by BFRIP regarding the use of brominated flame retardants shows that there is no evidence that the use of decabromodiphenyl oxide leads to any unusual risk. In addition, a study by the National Bureau of Standards (now National Institute of Science and Technology) showed that the use of flame retardants significantly decreased the ha2ards associated with burning of common materials under reaUstic fire conditions (73). Work ia Japan confirms this finding (74). 

Y. C. Wu, W. E. Koch, and R. A. Durst, Standardisation of pH Measurements, National Bureau of Standards Special PubHcation 260-53, U.S. Government Printing Office, Washington, D.C., 1988 National Institute of Standards and Technology, Gaithersburg, Md., private communication, 1993. 

JANAE U.S. Department of Commerce National Institute of Standards and Technology chemical thermodynamic properties of inorganic substances and of organic substances containing only one or two carbon atoms... 

NIST Update High Tech PubUshiag Co. NewsNet news and information on activities of the U.S. National Institute of Standards and Technology (NIST)... 

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