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Tadej Podgornik, Valentin Batagelj, Jovan Bojkovski, Janko Drnovšek
NONLINEARITY TESTING OF EQUIPMENT USED IN TEMPERATURE MEASUREMENTS

In this paper the nonlinearity testing of seven resistance instruments used to measure temperature is presented. Tested were four multi-meter type instruments which use the UI method to determine resistance and three resistance bridges that measure resistance as a ratio between a resistance thermometer and a standard resistor.
The device used to measure the nonlinearity of the instruments was a RBC100 resistance bridge calibrator. The device is a passive four resistor matrix that enables for 35 different resistances to be generated by parallel/series switching of the four base resistors. The device had been previously automated for easier use. This eliminates the need for an operator to be present during calibration, the device can also be placed in an thermally stable enclosure and switched from within it. The software that was purposely developed for the automated work with the RBC100 controls both the calibrator as well as gathers measurements from the instrument under test. The software also calculates non-linearity and keeps record of the measurements that were performed.
During testing, two rounds of measurement sets were performed. During each round 3 sets of all 35 combinations were measured on every instrument under test. The multi-meter type instruments nonlinearity was measured to be far lower than the declared uncertainty. The linearities of the resistance bridges were in most cases equal to the declared uncertainty value. This was however to be expected, since bridge nonlinearity accounts for the major part of its uncertainty. Non-linearities were in the range from 380 µΩ (6 ½ digit multi-meter) down to 2 µΩ (best resistance bridge).

Holger Nicklich, Martin Brucke, Michael Mende
THE NEED FOR CONTROLLED SHOCKS - A NEW TYPE OF SHOCK EXCITER ALLOWS TO APPLY WELL DEFINED MECHANICAL SHOCKS

Shock exciters available on the market today suffer from a lack of control of the generated shocks. This paper will present a new type of shock exciter developed by SPEKTRA which is based on the well known Hopkinson-Bar but using a piezoelectric actuator to apply the force pulse input (* patent pending). It will be shown that a piezoelectric actuator driven Hopkinson-Bar generates well defined shocks allowing the control of pulse width and amplitude independently over a wide range. Furthermore the spectrum of the applied shocks can be controlled accurately by shaping the input force pulse coming from the actuator. Thus this new shock exciter is a valuable tool for shock calibration in metrology as well as for sensor characterisation in development departments.

Agnieszka Bialek, Alistair B. Forbes, Teresa Goodman, Ruth Montgomery, Martin Rides, Gerie van der Heijden, Hilko van der Heijden, Gerrit Polder, Krista Overvliet
MODEL DEVELOMPENT TO PREDICT PERCEIVED DEGREE OF NATURALNESS

This paper presents the development of a mathematical model to predict the perception of naturalness for a range of materials, based on an understanding of the relationship between the physical attributes of the material and the human sensory inputs. The work is being carried out under an European Union project called 'Measurement of Naturalness' (MONAT), which focuses on understanding the relationships between the physical properties of natural and synthetic materials and the visual and tactile sensory processes that lead to perceptual judgments of naturalness. Integral to the project is the development of novel measurement facilities with dynamic ranges and sensitivities that are relevant for the human sensory systems. The input data to the model are derived from psychophysical and physical studies on pre-selected wood, textile and stone samples.

Ranny Michalski, Marco Nabuco, Gustavo Ripper
UNCERTAINTY INVESTIGATION OF FIELD MEASUREMENTS OF AIRBORNE SOUND INSULATION

Sound insulation is very important for the acoustic quality of buildings. The Brazilian Association of Technical Standards, ABNT, published a set of standards concerning the evaluation of the performance of buildings up to five floors, ABNT NBR 15755, and sound insulation is one the considered topics. Minimum, intermediate and superior values are presented for some acoustic parameters. In order to make measurements carried out by different professionals comparable with the values established in the standards, the uncertainty of the results shall be expressed. The Guide to the Expression of Uncertainty in Measurement, ISO/IEC Guide 98 (GUM), is the international document that standardizes how to assess the uncertainty of a measurement result.
In general, two types of methods are used to measure sound insulation parameters: the classical method and the new method or impulsive response method. However, there is not an established and simple procedure to obtain the measurement uncertainty. Uncertainties estimates are available only for the classical method.
Measurements of airborne sound insulation between rooms were carried out in field conditions with the impulse response method and the work presents a study of the estimate of the uncertainties of the results, in accordance with the GUM.

Leszek Rozanski, Stanislaw Poloszyk
INFLUENCE OF RADIATION DIFFRACTION UPON METROLOGICAL PARAMETERS OF THE IR LINE SCANNER

The influence of IR radiation diffraction upon geometrical resolution of the IR line scanner has been analysed in the paper. Analysis of IR line scanner properties in band 3 – 5 µm and 8 – 12 µm proved that when applying the aperture diaphragms the influence of the radiant diffraction upon geometrical resolution may be significant. This influence is stronger for larger f numbers N in the applied optical systems. It was shown that for large values of f numbers the thermal resolution of the IR line scanner can be improved by reducing the bandwidth of the electronic system of the scanner, without considerable deterioration of geometrical resolution.

Ales Hribernik, Maja Bauman, Aleksandra Lobnik
APLICATION OF 2k FACTORIAL DESIGN IN WASTEWATER DECOLORIZATION RESEARCH

This research deals with the decolorization of synthetic wastewater prepared with 1:2 metal complex textile dye C.I. Acid Blue 193 by AOP ozonation (O3) and H2O2/O3 process. In order to minimize the number of experiments, experiments were performed using the 25 factorial design. Five influential parameters were examined: initial dye concentration, ozone flow rate, initial pH value, decolorization time and H2O2 addition. According to the variance test analysis, only the first four parameters and their first and higher order interactions are significant, while the fifth factor, i.e. H2O2 addition, proved insignificant within the range examined in our tests. With the help of the significant factors, a regression model was constructed and model adequacy checked. The obtained regression polynomial was used to model the relation between absorbance and influential process parameters by fitting the response surface. Response surface may be used to predict absorbance resulted from a set of influential parameters, or it can be rearranged in such a way to predict the set of process decolorization parameters, necessary to reduce the absorbance of wastewater with the given initial dye concentration below the prescribed limit. It is also shown that 2k factorial design can be suitable to predict ozonation operating expenses.

Craig Coull, Edmund Spearman, Jason Laidlaw
REAL LIFE ULTRASONIC FLOWMETER VERIFICATION FOR UPSTREAM CUSTODY TRANSFER METERING NATURAL GAS

Ultrasonic gas flowmeters (USM) employing multiple paths and transit time technology are becoming established in the upstream oil and gas industry for custody transfer flow measurement. This is mainly due to the advantages of wider flow range capability, and lower pressure loss over that of conventional differential pressure type flow meters such as orifice plates.
It is now more than a decade since ultrasonic meters were first applied to high accuracy gas flow metering, and standards and guidance documents have developed much in this time. However in the area of on-going measurement verification procedures, there is still minimal standardisation. Current standards provide guidance but leave ongoing verification procedures to the parties involved. Industry regulators such as government departments, pipeline operators etc require that flow measurements are verified on an ongoing basis to the required uncertainty levels.
This paper describes a custody transfer USM metering station (measurement uncertainty of ±1%) installed on the Petrojarl Banff an FPSO (Floating Production, Storage and Offload vessel). It describes the specifically developed verification techniques, and reviews verification data collected over 4 years of operation.
The verification procedures applied have been successful in satisfying the pipeline operator of the suitability of the ultrasonic metering station. It is proposed that the procedures described could form the basis for industry standard USM verification.

Hamza Alkhatib, Ingo Neumann, Hansjürg Kutterer
EVALUATING UNCERTAINTIES OF LASERSCANNER MEASUREMENTS BY USING A JOINT MONTE CARLO AND FUZZY APPROACH

The evaluation of uncertainties according to the "Guide to the Expression of Uncertainty in Measurement" is presented in this study based on a novel Fuzzy-random-variables approach. Whereas the classically proposed methods like Monte Carlo techniques treat all uncertainties as having a random nature, the fuzzy technique distinguishes between aleatoric and epistemic uncertainties. The aleatoric components are modeled in a Monte Carlo framework, and the epistemic uncertainties were treated with fuzzy techniques. The applied procedure is outlined showing both the theory and a numerical example for the evaluation of uncertainties in an application for terrestrial laserscanning.

Daniel Schwind, Torsten Hahn
INVESTIGATION OF THE INFLUENCE OF CARRIER FREQUENCY OR DIRECT CURRENT VOLTAGE IN FORCE CALIBRATIONS

This paper describes analysis and evaluation of calibration of several force transducer types, each transducer first calibrated by a precision amplifier at 5 V 225 HZ carrier frequency excitation voltage and second by a precision amplifier at 5 V direct current excitation voltage. Some calibrations were made according to ISO 376 in order to determine the uncertainty; much more calibrations were performed in two series with changing amplifier in order to detect the influence of the excitation voltage. There were two goals of the investigation: The first goal was to achieve confidence of the different calibration equipment for carrier frequency and direct current voltage by statistical data, the second goal was to experience the interchangeability of two different amplifier types on different transducer types.

Sara Lietz, Falk Tegtmeier, Dirk Röske, Rolf Kumme, Daniel Schwind
INVESTIGATION AND CALIBRATION OF A FORCE VECTOR SENSOR WITH A CALIBRATION ARTEFACT

This paper deals with the investigation of a new type of force vector sensor developed by Gassmann Testing and Metrology (GTM). The measurements were performed in the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig. The new force vector sensor is capable of measuring the main axial force and six secondary components: two side forces perpendicular to the main axis, three axial forces arranged in a triangle parallel to the main axis and furthermore a moment with the main axis of the sensor as axis of rotation. With these components one can describe the force as a vector giving the amplitude of the force vector, its direction and the force application point.

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