A novel technique has been developed to verify the absolute accuracy and relative stability of a spaceborne microwave radiometer’s calibration using a statistical analysis of the measured Earth brightness temperatures (TBs). This procedure relies solely on the final, main beam-referenced TBs and so tests the complete end-to-end system calibration, including instrument temperature and non-linear...

Machine tool calibration requires a wide range of measurement techniques that can be carried out in many different sequences. Planning a machine tool calibration is typically performed by a subject expert with a great understanding of International standards and industrial best-practice guides. However, it is often the case that the planned sequence of measurements is not the optimal. Therefore...

in this study, 60 composite samples of dill and onion from two different cultivated areas in khozestan province, iran, were collected and analyzed for the presence and determination of lead and cadmium by flame atomic absorption spectrometry. samples were burned according to aoac at 450 °c, and the residue was dissolved in nitric acid. lead and cadmium contents were determined using calibration...

Digital Fourier filtering is used to produce a temperature-insensitive univariate calibration model for measuring lysozyme in aqueous solutions. Absorbance spectra over the 5000-4000 cm-1 spectral range are collected for lysozyme standards maintained at 14 degrees C. These spectra are used to compute the calibration model while a set of spectra collected at temperatures ranging from 4 to 24 deg...

A neutron spectrometer was acquired for use in the measurement of National Institute of Standards and Technology neutron fields. The spectrometer included options for the measurement of low and high energy neutrons, for a total measurement range from 0.01 eV up to 17 MeV. The spectrometer was evaluated in calibration fields and was used to determine the neutron spectrum of an Americium-Berylliu...

The degree to which measurement accuracy in a vector network analyzer can be improved through error correction is dependent on a number of factors. Modern error correction methods have improved the system accuracy and simplified the calibration procedure. Methods are in place to determine the accuracy of error corrected measurements. And the quality of the calibration standards is key to system...

National Bureau of Standards Gaithersburg, MD 20899 To provide a phase meter calibration service, a phase angle calibration standard has been developed at NBS. This standard is a signal. generator with two sinusoidal outputs and uses direct digital synthesis to generate the signals. The phase angle between the two sinusoids is determined by the input parameters in the calculation of the sets of...

This paper deals with the definition of the input fluxes used for the calibration of the IUE Final Archive. The method adopted consists on the determination of the shape of the detector’s sensitivity curves using IUE low resolution observations with model fluxes of the DA white dwarf G191–B2B. A scale factor was then determined so that the IUE observations of some bright OAO–2 standards match t...

The National Institute of Standards and Technology (NIST) polyethylene-encapsulated 226Ra/222Rn emanation (PERE) standards (old SRM 4968 and new SRMs 4971, 4972, and 4973) provide precise radon emanation rate, certified to a high degree of accuracy (approximately to 2%). Two new SRM 4973 standards containing totally 1036 Bq (0.028 microCi) of 226Ra, emanate 0.114 Bq (3.08 pCi) of 222Rn per min....

The calibration of measurement systems is a fundamental but under-studied problem within industrial statistics. The origins of this problem go back to basic chemical analysis based on NIST standards. In today’s world these issues extend to mechanical, electrical, and materials engineering. Often, these new scenarios do not provide ”gold standards” such as the standard weights provided by NIST. ...