Monochromatic radiation source for calibration of the relative spectral sensitivity of earth observation instruments

The design of the major components and parts of a wide-aperture monochromatic radiation source for calibration of earth observation instruments, and its technical and metrological characteristics, are discussed. The uncertainty budget for reproducing the relative spectral distribution of the source at wavelengths of 0.3–2.5 μm is calculated.     

Some methods for redefining the unit of mass standard fundamental problems in metrology

Contemporary methods are presented for redefining the unit of mass standard, i.e., the kilogram prototype. The main tendencies in improving these methods in order to reduce the uncertainty of reproducing the unit of mass are discussed. It is noted that the use of precise values of a number of fundamental physical constants, primarily the Avogadro number, is important. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 3–7, April, 2006.     

Metrology: quo vadis?

Metrology, the science of measurement, has become an essential part of the technical infrastructure of industrialized countries. In cooperation with the BIPM, the national metrology institutes realize, maintain, and disseminate the units of the SI (Systeme International d'Unites), so making accurate measurements available to all users. The discovery of the macroscopic quantum effects provided the means of reproducing certain electrical units with an uncertainty considerably smaller than that of direct realization according to their SI definition. The reproduction of units in this way has become an important method of improving their maintenance and dissemination. The article highlights the advantages of such a method: it is general, it will certainly be extended to units other than electrical ones and it will generally improve the paths of traceability resulting in a better worldwide metrological network     

Broadening the functional scope of the state standard of initial permeability GÉT 122-80

The results are presented of theoretical and experimental investigations during the active maintenance of the State Standard GéT 122-80. Recommendations are given for broadening the functional scope of the standard. An analysis is made of the errors in reproducing the units of complex permeability components. Translated from Izmeritel'naya Tekhnika, No. 10, pp. 55–57, October, 1998.     

Apparatus for realizing the ITS-90 in the temperature range from the triple point of argon to the melting point of gallium

Systems for realizing the fixed points of the ITS-90 for calibrating column and capsule standard platinum thermometers, namely, the triple points of argon and mercury and the melting point of gallium, are constructed and investigated. The errors of the values of the metrological characteristics of the systems obtained enable one, using platinum resistance thermometers, to reproduce and transfer the temperature scale in the 83.8–302.9 K range. The extended uncertainty in reproducing the temperatures of the fixed points does not exceed 0.4 mK. This paper has been prepared from the contributions presented at the 3rd All-Russia Conference “Temperature 2007”; see the selection of papers in Measurement Techniques, Nos. 8 and 9, 2007. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 26–31, November, 2007.     

Production of the unit of capacitance

Conclusion The perfection of the complex of measuring means that are presently a state primary standard of the farad of the USSR have as their purpose a further decrease in the error of reproducing the farad, which must be decreased and brought to between 1·10^–7 and 2·10^–7. An important role, namely the perfection of indirect methods and an increase in the precision of reproducing still other electromagnetic units, was assigned to the primary standard of the unit of capacitance in the course of perfecting the system of standards of units of electrical magnitudes [4], These units include resistance, inductance, magnetic flux, and magnetic induction, whose reproduction error in the new system of standards will be decreased to between one-third and one-half.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 76–78, April, 1976.     

Comparison of the dimensions of electrical resistance units, supported on the basis of the hall quantum effect, in the All-Russia Research Institute of Metrological Service and the Czech Metrological Institute

VNIIMS (Russia) and CMI (Czech Republic) quantum Hall resistance standards are compared using a VNIIMS portable resistance standard of 1 and 10 kΩ. Conformity is established for the dimensions of units within the limits of relative expanded (k = 2) uncertainty of 10⁻⁷. Translated from Izmeritel’naya Tekhnika, No. 12. pp. 58–61, December, 2008.     

Interpolation functions in the immersed boundary and finite element methods

In this paper, we review the existing interpolation functions and introduce a finite element interpolation function to be used in the immersed boundary and finite element methods. This straightforward finite element interpolation function for unstructured grids enables us to obtain a sharper interface that yields more accurate interfacial solutions. The solution accuracy is compared with the existing interpolation functions such as the discretized Dirac delta function and the reproducing kernel interpolation function. The finite element shape function is easy to implement and it naturally satisfies the reproducing condition. They are interpolated through only one element layer instead of smearing to several elements. A pressure jump is clearly captured at the fluid–solid interface. Two example problems are studied and results are compared with other numerical methods. A convergence test is thoroughly conducted for the independent fluid and solid meshes in a fluid–structure interaction system. The required mesh size ratio between the fluid and solid domains is obtained.     

Precision equipment for reproducing particle sizes and numerical concentrations in aerosols, suspensions, and powders

Precision equipment is described for reproducing the unit of numerical concentration and size for particles in aerosols, suspensions, and powders in the concentration range from 4·10⁷ to 4·10¹³ m⁻³ with average particle dimensions of 1–100 μm. The apparatus is based on small-angle laser-beam scattering and Beer's law. The optical system is described. The residual systematic error in reproducing the numerical concentration and unit does not exceed 12% in the above concentration and size ranges. Translated from Izmeritel'naya Tekhnika, No. 9, pp. 68–70, September, 1997     

The Combined Use of a Gas-Controlled Heat Pipe and a Copper Point to Improve the Calibration of Thermocouples up to 1100 ˚C

The calibration of platinum-based thermocouples from 420 °C to 1,100 ˚C is currently carried out at INRIM making use of two different apparatus: for temperatures below 930 ˚C, a potassium gas-controlled heat pipe (GCHP) is used, whereas a metal-block furnace is adopted for higher temperatures. The standard uncertainty of the reference temperature obtained in the lower temperature range is almost one order of magnitude better than in the higher temperature range. A sealed copper cell was investigated to see if it could be used to calibrate thermocouples above 930 ˚C with a lower uncertainty than our current procedures allowed. The cell was characterized with Type S and Pt/Pd thermocouples and with an HTPRT. The freezing plateaux were flat within 0.01 ˚C and lasted up to 1 h with a repeatability of 0.02 ˚C. The temperature of the cell was determined with a standard uncertainty of 0.04 ˚C. Hence, the copper cell was found to be superior to the comparator furnace for the calibration of platinum-based thermocouples because of the significant decrease in the uncertainty that it provides. An analysis was also carried out on the calibration of Pt/Pd thermocouples, and it was found that the combined use of the potassium GCHP and the Cu fixed-point cell is adequate to exploit the potential of these sensors in the range from 420 °C to 1,084 °C. A comparison with a fixed-point calibration was also made which gave rise to agreement within 0.07 ˚C between the two approaches.     

Components of a Variance Model for the Analysis of Repeated Measurements in Fixed-Point Comparisons

Experimental design is a statistical tool concerned with the planning of experiments to obtain the maximum amount of information from the available resources. This tool may be applied to metrology, especially for the analysis of a large number of repeated measurements (replicates) of short-term repeatability and the medium-term and long-term reproducibilities, enabling the inclusion of these “time-dependent sources of variability” in the uncertainty budget. The realization of the International Temperature Scale of 1990 (ITS-90) scale requires that laboratories usually have more than one cell for each fixed point, for comparison on a regular basis. The calculation of the uncertainty of such comparisons is considered here, taking into account these time-dependent sources of variability. These components of the uncertainty evaluated by a Type A method are obtained by the statistical analysis of the experimental results using the components of a variance model for designs consisting of nested or hierarchical sequences of measurements, as foreseen by the mainstream GUM. An application example of a balanced nested structure in the comparison of two fixed-point cells is presented.     

Viscoelastic behaviour during the crystallisation of isotactic polypropylene

Morphology and viscoelastic behaviour during the initial stages of crystallisation of isotactic polypropylene were explored as a function of time and angular frequency by light microscopy and dynamic oscillatory rheology. Results were evaluated according to the Krieger-Dougherty and Palierne models for viscoelastic suspensions of spheres. The data obtained from light microscopy were introduced in the rheological models reproducing quite well the viscoelastic response during crystallisation. The Palierne model was able to describe the behaviour of the system, though it was not possible to observe all the model’s features due to a limited angular frequency range. Further, at high filler contents, an ‘equilibrium’ modulus needs to be introduced for the model to fit the experimental data. The exponent required to model the changes occurring in the ‘equilibrium’ modulus over time resembles that of chemical gelation more than physical gelation.     

Highly accurate measurements within the international system of units

Physics today presents a consistent model of natural phenomena based upon a coherent system of units of physical quantities. Knowledge of the most accurate values of the most important fundamental constants is essential for the traceability of units and for the refinement of theory. Of the four base units in the International System of units relevant to electrodynamics, the ampere can as yet only be realized with poor relative uncertainty of the order of 10^-6; the same holds true for the derived electric and magnetic units with the exception of the ohm. The accurate measurement of the gyromagnetic ratio of the proton γppromises to yield a more accurate realization of the ampere than that achieved using the traditional current balance.     

Primary state standard of the unit of inductance — The henry

Conclusions The standard of the henry is the first (with respect to its approval) state standard in the range of inductance, capacitance, and resistance measurements.This standard served up to the beginning of the sixties as the only initial (computed) quantity, on whose basis the VNIIM determined by indirect means the absolute values of the units of capacitance and resistance. The error of these indirect methods for reproducing units was of the order of 10^–5.Investigations, including circulatory international comparisons, of working standards have shown that the precision and accuracy of reproducing inductance units in the USSR are at the level of the best results obtained in national metrological institutes.In recent years new, more precise methods for reproducing resistance units have appeared. These methods, as well as the application of new types of measuring equipment, made it possible to extend substantially the nominal values' range of inductance standards covered by the test schematic.In order to ensure uniformity in this field of measurements, it is necessary to have a set of mutually-related computed inductance and capacitance standards (Fig. 3).The State Committee of standards attached to the USSR Council of Ministers approved, in accordance with the VNIIM recommendations, the coil types PB-1, KB-1, KB-2, and KB-3 as primary state standards of the henry. Prof. Igor' Nikolaevich Krotkov,head of the VNIIM laboratory,was appointed scientific keeper of this State standard.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 7–11, October, 1972.     

Triple helix in the agricultural sector of Northeast Asian countries: a comparative study between Korea and China

In this paper, the agricultural innovation systems of two Northeast Asian countries—Korea and China—are investigated and compared from the perspective of triple helix innovation. Specifically, the current study examines the nature of agricultural innovation of the two countries and considers agricultural R&D investments and activities as well as the roles of university, industry, and government (UIG), which are the three units comprising the triple helix. As an empirical extension of the qualitative analysis, we collected bibliometric information of agricultural scientific publications from 1990 to 2010 and patent information from 1980 to 2010. By calculating transmission of uncertainty, which indicates collaboration among UIG, this paper tracks the relationship dynamics of the units comprising the triple helix. In addition, we analyze topics in scientific publications and patents in order to observe and compare the subareas that are the focus in the two countries. The findings reveal both commonalities and differences between the two countries, thus providing knowledge of and insights into the agricultural sector.     

A standard system for producing very-short electromagnetic pulses with a rise time of 20 psec

The results of the development and construction of a standard set of units of electric and magnetic field pulse strengths with a pulse length of down to 1 nsec and a rise time of less than 20 psec, using a “cone over a plane” field-generating system are presented. Investigations were made of its amplitude-time characteristics using broadband measuring converters and couplers, included in the measuring system.     

Calculated Uncertainty of Temperature Due to the Size-of-Source Effect in Commercial Radiation Thermometers

The article evaluates the uncertainty in the temperature indicated by a radiation thermometer with a direct readout in temperature, due to the uncertainty in measuring the size-of-source effect (SSE) by the so-called “direct method.” Radiation thermometers of this type are the ones most frequently used in practice. The uncertainty of the SSE characteristic is usually not a useful quantity to report to users of commercial radiation thermometers. Instead, they would prefer to know the uncertainty in the measured temperature that results from the uncertainty of the SSE characteristic, and this will be the result of our analysis. The user of a direct reading radiation thermometer will be able to take into account the uncertainty of temperature due to the SSE, if a target with known dimensions is measured. The uncertainty in temperature due to the SSE of analyses based on Planck’s law and its approximation, Wien’s law is compared.     

Realization of Radiance Temperature Scale from 500K to 1,250K by a Radiation Thermometer with a Thermal Detector

The radiance temperature scale from 500K to 1,250K was realized by using a thermal detector transfer reference thermometer (TRT) with its spectral response centered at 3.9μm. The TRT is calibrated at the four fixed points of tin, zinc, aluminum, and silver, and the scale is obtained by interpolation with Wien’s equation, Planck’s equation, the Sakuma–Hattori (SH) formula, and a Planckian SH (PSH) formula. The interpolation uncertainty dramatically decreases as the physical model for the interpolation equations becomes more realistic. The uncertainty of the scale is evaluated, including the repeatability of the calibration and the long-term stability of the TRT over a period of more than 20 months. The realized scale over part of the interpolation region was validated by comparing it with the ITS-90, resulting in excellent agreement within 0.09 K. The resulting uncertainty of the realized scale varies from 0.06K to 0.38K (k = 1), depending on the temperature.     

Dynamic Measurements of the Temperature Coefficient of Resistance in the Transient Plane Source Sensor

The extended dynamic plane source (EDPS) method is one of the transient methods for measurements of the thermal conductivity and thermal diffusivity in solids. This technique uses a transient plane source (TPS) sensor, which serves as the heat source and thermometer. Its calibration consists of measuring the temperature dependence of the TPS sensor resistance and computing the temperature coefficient of resistance (TCR) using least-squares (LS) estimation. The goal of this study is to calibrate the TPS sensor directly in the apparatus for the EDPS method. The article presents an uncertainty assessment of the TCR measurement. The main sources of uncertainty stem from resistance measurements of the constant resistor and platinum thermometer calibration. The LS estimate of the TCR in a nickel TPS sensor is 4.83 × 10⁻³ K⁻¹ at 20 °C and 4.57 × 10⁻³ K⁻¹ at 45 °C with a combined standard uncertainty better than 0.04 × 10⁻³ K⁻¹, which is 0.7 %.     

Hygrometry in units of a thermometric scale

Use of a single term, i.e., “dew point,” for the quantitative characteristic of gas moisture expressed in units of a thermometric scale is substantiated. Features and conditions of the correct application of this term and also calculation methods for evaluating phase equilibrium parameters in a water in the condensed state-compressed gas system are described. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 46–48, January, 2006.