IMEKO Event Proceedings

Page 855 of 855 Results 8541 - 8545 of 8545

Yasushi Azuma, Kenji Odaka, Akira Kurokawa, Toshiyuki Fujimoto
X-RAY REFLECTIVITY MEASUEMENTS FOR DEPTH DENSITY DISTRIBUTION IN THERMAL OXIDE THIN FILM ON SILICON (100)

X-ray reflectometry (XRR) is a powerful tool for the structural characterization of thin films. However the standardized protocols of the measurements and their analyses need to be established for the reliable and reproducible characterization. The collaborative work between National Institute of Standards and Technology (NIST, USA) and National Metrology Institute of Japan (NMIJ, Japan) for thickness evaluation by XRR has been carried out in order to support the activities for the standardization of the thickness evaluation. In order to evaluate the accurate thickness of thin film structures by XRR experiments, the appropriate model construction of the structures should be required for the XRR data analysis. However there have been numerous discussions about the structures especially around the film/substrate interface. We tried to clarify a depth density distribution of a thermal oxide thin film on a Si substrate by comparing the XRR results obtained from several films which were oxidized by different processes.

Adamopoulou, E., Leloudi, M. C., Hatzidimitriou, E.
Xinomavro Naousa red wines typicality; linking sensory and physicochemical data

Typicality rating of 10 red wine samples, using a non-structured scale, at left “very bad example”, at right “very good example” of what a panel of wine experts, professionals, initiated assessors and consumers, considered to be a typical Xinomavro Naoussa wine, was combined to physicochemical analysis (color characteristics, phenolic content) and GC analysis of volatile profile. Assessors were able to successfully identify the Xinomavro Naoussa samples and rate them as the most typical. Based on both physicochemical and sensory data, wines were successfully grouped according to composition and origin (monovarietal or blended, Naoussa or other PDO’s).

Bojana Radojkovic, Slavica Ristic, Suzana Polic, Aleksandar Krmpot, Branislav Salatic, Jovana Orlic, Filip Vucetic
XRF and LIBS Measuring on Metal and Ceramic Laser-Cleaned Surfaces

The use of lasers in the conservation of artefacts plays an important role since its posibilities of safe, efficient and efective cleaning on complex surfaces and wide range of materials. This paper presents the results of the laser cleaning effects on ceramic medieval artefacts originated from archaeological sites from region of Tyre and Sidon, Lebanon and naturally tarnished brass plate (unknown origin). Nd:YAG and Er:Glass lasers were used to clean unwanted layers from artefact surface. Before these investigations, some preliminary analyses were conducted on the comparable contemporary samples. Effects on the laser irradiated zones were investigated by optical and SEM microscopy and EDX analysis. LIBS and XRF were used for the morphological and chemical analysis of laser radiation impact on the examined materials. Also surface 's profile roughness and surface hardness were measured. Some parameters for successfully and safely cleaning of brass surface without degrading the surrounding material were determined.

A. J. M. Herwijn, M. P. van der Beek, I. J. Landheer
Z/Z-METER, ON-LINE MEASUREMENT OF COMPRESSIBILITY-RATIOS FOR REFERENCE VALUES OF VOLUME AT OPERATIONAL CONDITIONS

One of the methods to realize reference values for Volume of e.g. Natural Gas at increased pressures is via a calibration under a pressure difference (i.e. with expansion). In such a process, applied since the sixties in the Netherlands, the "un-known" meter or Meter-under-Test (MuT) is compared through expansion with the "known" meter or Reference Meter (RM) at low-pressure. In a "normal" calibration-process the difference in pressure between the two compared meters is relative small and the resulting difference between the compressibility at the Reference Meter ZRM and the compressibility at the Meter-under-Test ZMuT has hardly any effect on the ratio ZRM / ZMuT and can be neglected (the ratio is thus considered to have a value of 1). However, in a calibration under expansion a comparison is made of a gas-flow under significant differential pressure-conditions and one of the most important contributions of uncertainty stems from the real gas constant Z. So, the ratio ZRM / ZMuT is of importance, rather than the absolute values of the compressibility factor. The Z / Z-meter is one of the current technical developments at NMi VSL-Flow. The uncertainty contribution in the conventional method of calculation, described e.g. in M-GERG of 1991, is rather high (0,1% for the compressibility factor) and the resulting uncertainty of the ZRM / ZMuT ratio is 0,14%.
Therefore, a method leading to a lower contribution to this source of uncertainty offers advantages. In the presented approach is the ratio ZRM / ZMuT is considered to be the measurand. The ratio should then be measured more accurately than the one resulting from calculation of the absolute values of the compressibility factor. As a consequence, the impact of this source of uncertainty is reduced. NMi has developed a device that is able to measure the ratio ZRM / ZMuT directly.
In this paper, the development of a new measuring instrument is described that measures the Z1 / Z2 ratio of gases (at pressures P1 and P2 between 1 and 70 bar) with a maximum uncertainty of 0,03%. The measuring principle of the Z / Z ratio meter is based upon the accurate measurement of a piston-displacement. The piston is displaced by a controlled gas expansion from high-pressure to a low-pressure condition (or for compression, vice versa) in a measurement cell. The measurement cell with an adjustable volume is mounted inside a high-pressure vessel for an adequate control of temperature and pressure. The cell is constructed as a cylinder-piston combination together with small ball-valve actuators that can be opened and closed to connect or disconnect the chamber of the cell to the surrounding vessel and to fill or empty the system.
During its operation, measurements are taken of the piston-displacement, together with measurements of pressures and temperatures. For the calculation of the ratio Z1 / Z 2 basically only the ratio of the cell volumes at pressures P1 and P2 needs to be established.

Gennadiy I. Peredelskiy
ZERO BIPOLAR MEASURING CIRCUIT

In the paper, results of substantiating analysis of the possibility application the frequent-independent two-terminals as zero measuring circuit are shown. It allows to determine not only reactive parameters, but also active resistances. Sensitivities of such measuring circuit are determined. Meter functional diagram and its usage are described.

Page 855 of 855 Results 8541 - 8545 of 8545