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Antti Vehkaoja, Jukka Lekkala
A SIMPLE BIOELECRICAL SIGNAL SIMULATOR FOR MEASUREMENT DEVICE TESTING

A very simple PC based system for simulation of bioelectrical signals is presented. In addition to a regular PC with an audio card and the constructed software only few passive components are needed to accurately mimic the waveforms of the original recorded bioelectrical signals stored in the PC's hard drive. Alternatively, the simulated signals that are generated from the original recordings by Matlab can be played back with an mp3-player. Due to the nature of our method and the bandwidth limitations of PCs' audio card, the system is not suitable for simulation of high frequency signals but for bioelectrical signals like electrocardiogram (EKG) the method suits very well.

Josep M. Torrents, Pablo Juan-García, Oriol Patau, Antonio Aguado
SURVEILLANCE OF STEEL FIBRE REINFORCED CONCRETE SLABS MEASURED WITH AN OPEN-ENDED COAXIAL PROBE

Conventional concrete structures are nowadays being substituted by steel fibre reinforced concrete (SFRC) in some structural applications. Then, fibre dosage and distribution is a keyword for ensuring quality control of structures. The present work analyses the possibility of an Open Ended Coaxial Probe as an element for ensuring the quality of a concrete slices.

Janez Setina, Bojan Erjavec
VOLUME DETERMINATION OF A VACUUM VESSEL BY PRESSURE RISE METHOD

A new method for determination of volume ratios and also the absolute value of volumes of vacuum vessels is presented. Method is based on a measurement of rate of pressure rise in a vacuum chamber at constant flow of inert gas. An example of measurement of a volume of a chamber with a nominal volume of 7 L is presented. For pressure measurements we have used a spinning rotor gauge (SRG) and He permeation leak was used as a gas source.

Alan G Steele, A. Peruzzi, J. E. Decker, R. J. Douglas
METROLOGICAL INSIGHTS FROM INTERNATIONAL COMPARISON DATA

The full suite of tools for the evaluation of statistical consistency of metrological data is applied to the data set compiled from two recent international comparisons: CCT-K7 and EURAMET.T-K7. This paper illustrates how insights into lab measurement characteristics such as repeatability, reproducibility, secular uncertainties and laboratory equivalence statements can be obtained in a statistically-rigorous manner.

Salvatore Lorefice, Elena Amico di Meane, Michela Sega
THE USE OF GC-MS TO SUPPORT STABILITY ASSESSMENT OF DENSITY REFERENCE LIQUIDS

Density measurements are frequently associated to specific requirements in order to evaluate the quality of a process or to determine mass and/or volume of the material. Certified reference liquids can be used to assure metrological traceability of density measurements to the International System of Units (SI) with uncertainty lower than 0.005 %. This paper presents the new approach of the Italian Istituto Nazionale di Ricerca Metrologica (INRIM) to set density standards.
The procedure involved accurate density determinations of some liquid samples, to be used as references, on which in addition analysis by means of gas-chromatography coupled with mass spectrometry (GC-MS) was performed to support homogeneity and short-term stability. In this exercise GC-MS analyses on two chlorinated liquids (namely tetrachloroethylene and trichloroethylene) were carried out before and after density measurements. The results obtained with the two different techniques were encouraging. Samples that had undergone to variations in density value showed also different gas-chromatographic profiles. In the same time, samples that had not undergone to density variations kept similar gas-chromatographic profiles. The results support the approach of combining independent methods in order to set physico-chemical properties of reference materials (RM), univocally.

Ikuo Ihara, Manabu Takahashi
A NOVEL ULTRASONIC THERMOMETRY FOR MONITORING TEMPERATURE PROFILES IN MATERIALS

A new ultrasonic method for monitoring the temperature distribution inside a material being heated or cooled is presented. The principle of the method is based on the temperature dependence of the velocity of ultrasonic wave propagating through a material. An effective inverse analysis coupled with a finite difference calculation is used to determine the one-dimensional temperature distribution inside a thick plate. To verify the practical feasibility of the ultrasonic method, experiments have been demonstrated. A single side of a steel plate of 30 mm thickness is heated by contacting with a heater of 200 ºC and subsequently cooled down by water. Ultrasonic pulse-echo measurements are then performed for the steel during the heating and cooling. A change in the transit time of longitudinal ultrasonic waves across the steel is continuously acquired and used to determine the temperature distribution inside the steel. The temperature distribution and its transient variation determined by the ultrasonic method almost agree with those obtained using thermocouples installed in the steel. Thus, it is verified that the present method can be a promising means for real-time monitoring of temperature profiles in materials being heated or cooled.

Alessandro Germak, Claudio Origlia
NEW POSSIBILITIES IN THE GEOMETRICAL CALIBRATION OF DIAMOND INDENTERS

The influence of Rockwell and Vickers diamond indenters geometry in hardness measurements justifies the strict specifications and tolerances in the relative standards. Many methods, and consequently dedicated instruments, have been developed to investigate the geometrical parameters in order to calibrate the diamond indenters. Most of them, using contact or contactless methods, can only investigate some profiles of the indenters; from these partial measurements the whole geometry is derived. Few other instruments can investigate the whole shape but, since they are custom-developed, costs and difficulties in the calibration of these instruments have limited their use.
A new method is proposed in this paper using a commercial and not dedicated instrument: a 3D measuring confocal microscope. This type of instrument have also the advantage that the whole geometry is analyzed with a consequently knowledge improvement in the indenter calibration.
In the paper the measurement method, the used instrument and its calibration to assure traceability to the length and angle standards are investigated.

Giampaolo E. D'Errico
TESTING FOR OUTLIERS BASED ON BAYES RULE

A Bayesian treatment of conjectured outlying observations is developed, using the computational device of inverse probability. The device's performance is discussed in term of posterior probability of missed or false detections. The key role of prior probability is shown through a numerical example.

Francesco Adamo, Filippo Attivissimo, A. Di Nisio, Anna M. L. Lanzolla, Maurizio Spadavecchia
PARAMETERS ESTIMATION FOR A MODEL OF PHOTOVOLTAIC PANELS

The paper describes the first results of a simulation and characterization tool useful to evaluate electrical performances of photovoltaic (PV) panels. A simple one-diode model is used in order to estimate the electrical parameters of a PV panel and predict how the I-V characteristic changes with environmental parameters such as temperature and irradiance.
This work is part of a wider project whose final purpose is to model a whole PV plant in order to control its performances in various environmental conditions and maximize the energy production. The continuous monitoring of a plant and the comparison between real and expected data will also greatly reduce the risk of out of order.
The used model is implemented as a MATLAB® script which yields the I-V and P-V characteristics of the PV panel under test. The model has been validated against an experimentally characterized PV panel. Some parameters of the model have been measured directly (irradiance and temperature) whereas others have been evaluated in two distinct ways: by means of direct computation on the data sheet or by means of best-fit on the measured data, and the results have been compared.

Yasuhiro Mizutani, Yoshiyuki Uehane, Tomohito Kuwagait, Yukitoshi Otani, Norihiro Umeda
DETECTION OF SUBWAVELENGTH STRUCTURE PROFILE BY DECOMPOSITION OF MUELLAR MATRIX

Recently, the surface profiles of subwavelength structure have been reduced in size in order to develop microfabrication techniques. In particular, feature sizes of a few tens of nanometres are common in the semiconductor industry. This study uses a Mueller matrix polarimeter, which is based on a scatterometry technique, to evaluate the surface profiles of subwavelength structure. In this technique, a profile of the structure is determined from the Mueller matrix which expresses all the polarization properties of the sample by experimental measurements and calculated values. Furthermore, the Mueller matrix is decomposed for more precise detection. In this paper, the experimental results after decomposition agree well with the values obtained by numerical analysis. We measured the characteristic of non-diagonal elements in the Mueller matrix by varying the incidence azimuth of the subwavelength structure.

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