No. 1

  No. 2

      No. 3

 No. 5

  Theoretical Problems of Measurement

   Pages

E.-G. Woschni:

Information on Theoretical Investigations in Measurement, Particularly on Reading of Instruments

Abstract:  The paper presents the results of investigations with a group of students dealing with the accuracy of reading of instruments, using information theory. After a short introduction to information theory and Shannon´s channel capacity, the relation between the reading error and the reading time is discussed, leading to the results with reference to the limiting (critical) frequencies obtainable. Using these results, the channel capacity may be calculated. When these quantities of the channel capacity are compared with other values obtained from the literature it follows the same order of magnitude of 10 bits per second. Finally, using information theory again, the consequences are deduced. Due to the development of digital methods in microelectronics with decreasing approximation errors as well as with decreasing cut-off and aliasing errors will be the future. This is especially important for direct-coupled digital sensors, which have been used increasingly.

Keywords:  reading of instruments, information theory, channel capacity

S. Ďuriš, R. Palenčár, J. Ranostaj:

Contribution of the SPRT Calibration to Uncertainty of Temperature T90 Measured by the Calibrated SPRT

Abstract:The propagation of uncertainties, when the International Temperature Scale of 1990 (ITS-90) is used by a standard platinum resistance thermometer (SPRT) calibrated at defining fixed points (DFP), can be solved by applying several approaches. The article presents an analysis of contribution of covariance between resistances of SPRT at the defining fixed points (DFP). Its effect on temperature measured by calibrated SPRT is demonstrated by using real calibration data.

Keywords:  ITS-90, standard platinum resistance thermometer, defining fixed point, calibration, uncertainty

11-13

E. Eremin:

On the Borders of Applicability of the Weighted Mean in Processing Measurement Results

Abstract: A theorem on the law of large numbers for the estimator of the mean weighted first (initial) moment of the joint distribution of independent random variables is proved. The conditions for statistical stability of this moment and consistency of its mean weighted estimator are established.

Keywords: estimated (measured) physical quantity, mean weighted, random variables, consistency.

  Measurement of Physical Quantities

S. Takayama, M. Hiraoka, K. Mori, K. Kariya:

Variable Data Flow Management in Wireless Sensing Network for Landslide Disaster

Abstract:  Sensing systems to monitor natural disasters face many hard conditions. Natural disasters occur suddenly, and damage the sensor system. Therefore, the sensor system should be designed as a distributed node network. In addition to that, the network should have some characteristic functions, such as self-recovery, autonomous operation and effective data transmission. This paper describes an effective data flow management in wireless sensing node network for landslide disasters. The sensing node network is operated by three modes (initializing, measuring and urgent). By switching these operation modes autonomously, the sensing node network becomes a robust system (loss/insert) of sensing node and the dynamic control of data transmission. Finally, the effectiveness of the operation is supported by some experiments.

Keywords: sensing network, landslide monitoring

R. Malarić, D. Ilić, K. Malarić:

Electromagnetic Interference in the Primary Electromagnetic Laboratory

Abstract:  This paper describes the measurements of the electromagnetic fields performed in the Primary Electromagnetic Laboratory at the Faculty of Electrical Engineering and Computing. Because of the many instruments present in the laboratory and the vulnerability to the ambient electromagnetic fields, it was interesting to investigate if the level of exposure to microwave frequencies exceeds the international and Croatian standards. The measurements were performed in the frequency range from 75 MHz to 3 GHz. The highest fields came from the nearby base station, but still less than 0.3 V/m, which is rather low.

Keywords: electromagnetic interference, precise measurements, selective radiometer

N. Khélifa:

Water Vapour Effects in Mass Measurement

Abstract: Water vapour density inside the mass comparator enclosure is a critical parameter whose fluctuations during mass weighing can lead to errors in the determination of an unknown mass. To monitor them, a method using DFB laser diode in the near infrared has been proposed and tested. Preliminary results of our observation of water vapour sorption and de-sorption processes from the walls and the mass standard are reported.

Keywords: mass metrology, air density, water vapour in air, sorption, de-sorption

 No. 2

  Theoretical Problems of Measurement

W. Gawędzki:

Comparison of Self-Calibration Methods for Measurement Channels in Respect of a Method of Conversion Functions Interpolation

Abstract: The paper suggests algorithms enabling self-calibration of measurement channels with linear as well as nonlinear conversion functions. To approximate conversion characteristics, interpolation methods are used. They are widely known; however, the essence of the suggested self-calibration method is the current modernization of interpolating functions parameters due to a suitable procedure. It enables correction of the two essential error components which may appear in the measurement channel  by means of evaluating  the current value of the real slope of the conversion characteristic as well as of the components describing nonlinearity generated by disturbing factors. The methods of self-calibration for measurement channels cooperating with non-electrical quantities sensors are compared. Interpolation of conversion functions is assumed as linear in intervals and polynomial. 

Keywords: self-calibration, non-electrical monitoring, sensors, interpolation

L. Michaeli, J. Šaliga, L. Sochová:

Integral Nonlinearity Correction Algorithm Based on Error Table Optimizing and Noise Filtering

Abstract: The main purpose of this paper is to present the external correction of analog to digital converters (ADC) integral nonlinearity and quantization noise based on the look up table method (LUT) combined with the averaging and Wiener filtering and dithering method. The LUT compression and LUT precision effect are also studied.

Keywords: integral nonlinearity, look up table method, averaging filter, dithering, memory requirement

A. Vâlcu, D. Boiciuc:

Subdivision or Multiplication? The Choice of Calibration Design for Multiples of Kilogram

Abstract: The realization, maintenance and dissemination of the SI base unit, the kilogram, is one of the tasks of the NMI’s mass laboratory and is assured by means of reference standards which are traceable to the International Kilogram Prototype through the mass of the National Prototypes. This paper describes the dissemination of mass scale from 1 kg reference standard to weights of E1 class between (1...10) kg, using one of the two methods of calibration: subdivision or multiplication. The paper compares the variance of each weight obtained by both methods. The presented subdivision method deals with a link of standards following the example of Mihailov – Romanowski where the measurements start downwards from 10 kg to 1 kg. The multiplication method is the one usually used in many calibration laboratories and starts from 1 kg to 10 kg. The paper also presents an example of calibration and uncertainty calculations.

Keywords:  mass, kilogram prototype, calibration, measurements

  Measurement of Physical Quantities

Yu.V. Chugui, A.G. Verkhogliad, V.S. Bazin, S.V. Kalichkin,V.E. Kalikin, S.N. Makarov, I.A. Vykhristyuk:

Optical Remote Dimensional Inspection of Live Contact Wire in Train’s Electro-Supply Network

Abstract: An optical structured illumination of 3D object as a light band method for automatic noncontact wear measurement and defects detection of a contact wire network is presented. The experimental device can extract main technological wire parameters like remaining height with RMS value down to 0.15 mm. Also the cross-sectional area of the wire can be measured with RMS area noise value of 1.5 mm2, which is sufficient for a confident decision-making related to the automatic wire wears and defects on railways, tram and trolleybus lines, and similar systems of vehicles electro-supply.

Keywords: structured light method, non-contact remote inspection, profiling, shape measurement, contact wire

A. Dočekal, V. Dynybyl, M. Kreidl, R. Šmíd, P. Žák:

Localization of the Best Measuring Point for Gearwheel Behaviour Testing Using Group of Adaptive Models Evolution

Abstract: This paper deals with signal processing for vibration analysis of the gear transmission. The main goal was localization of the best measuring point on the gearbox housing, which could provide the highest sensitivity to gearwheels vibration. Vibration measured at some selected points on the gearbox housing was analysed using methods of spectral analysis. The important frequencies in the vibration spectra and a value of their importance were estimated using Group of Adaptive Models Evolution. This work was done within the framework of experimental research concerned with testing and lifetime estimation of new designs of gearwheels. The lifetime of an examined gearwheel, which is mainly related to rise of pitting faults, was assessed by monitoring of a gearwheel vibration level.

Keywords: Spectral analysis, vibration, gearbox, gearwheel behaviour, Inductive Modelling, Group of Adaptive Models Evolution

F. Lackner, W. Riegler, P. H. Osanna, M. N. Durakbasa: 

High Precision Strain Gauge Based Sensor for Monitoring Suspension Forces at CERN

Abstract: At the end of 2007, the world’s largest particle accelerator, the LHC (Large Hadron Collider), will be ready to collide first particles. Protons will be accelerated in a ring of 27 km circumference, contained inside an evacuated pipe of 60mm diameter. At four interaction points, where the large particle detectors are placed, this beampipe is made from beryllium in order to limit the multiple scattering of particles on their way from the interaction point to the detector. In order to keep the sag in the pipe to acceptable levels, accurate monitoring of the forces in the cables, which hold the beryllium beampipe in place, is required. The beampipe is installed in an environment of 0.5 T magnetic field and is expected to absorb a dose of 1 Mrad in ten years. These special constraints and the lack of accessibility preclude most standard monitoring systems. Previous work has shown that strain gauge based systems work well under the described conditions. This report shows that the monitoring system for the ALICE beryllium beampipe requires a minimum sensor size which results in μV effective range for the signal. The device provides the requested resolution of 1 N.

Keywords: Strain gauge, suspension force, beampipe monitoring

 No. 3

  Theoretical Problems of Measurement

50-52

F. Rublík:

On the Discriminant Analysis in the 2-Populations Case
Abstract: The empirical Bayes Gaussian rule, which in the normal case yields good values of the probability of total error, may yield high values of the maximum probability error. From this point of view the presented modified version of the classification rule of Broffitt, Randles and Hogg appears to be superior. The modification included in this paper is termed as a WR method, and the choice of its weights is discussed. The mentioned methods are also compared with the K nearest neighbours classification rule.

Keywords: discriminant analysis, nearest neighbour rule, Gaussian Bayes classification rule, maximum probability error

  Measurement in Biomedicine

53-57

S. C. Manoharan, M. Veezhinathan, S. Ramakrishnan:

Comparison of Two ANN Methods for Classification of Spirometer Data

Abstract: In this work, classification of spirometric pulmonary function test data performed using two artificial neural network methods is compared and reported. The pulmonary function data (N=150) were obtained from volunteers, using commercially available Spirometer, and recorded by standard data acquisition protocol. The data were then used to train (N=100) as well as to test (N=50) the neural networks. The classification was carried out using back propagation and radial basis function neural networks. The results confirm that the artificial neural network methods are useful for the classification of spirometric pulmonary function data. Further, it appears that the Radial basis function neural network is more sensitive when compared to back propagation neural networks. In this paper, the methodology, data collection procedure and neural network based analysis are described in details.

Keywords: Spirometer, pulmonary function, obstructive disease, restrictive disease, back propagation neural network, radial basis function neural network

  Measurement of Physical Quantities

58-60

A. Roszkowski, M. Bogdan, W. Skoczynski, B. Marek:

Testing Viscosity of MR Fluid in Magnetic Field

Abstract: The purpose of this paper was to determine the coefficient of viscosity of a magneto-rheological fluid for different values of the magnetic field and to determine parameters at which the flow of the fluid through a capillary is stopped. To determine the coefficient of viscosity, a method of indirect measurement was implemented using a reference fluid with the known properties. A test stand with a capillary viscometer was constructed. The measurements showed that the viscosity of the magneto-rheological fluid was linearly dependent in a wide range of values of the magnetic induction.

Keywords: magneto-rheological fluid, viscosity, measurement

M. Hruškovic, J. Hribik:

Digital Capacitance and Inductance Meter

Abstract: A microcomputer-controlled measuring instrument for capacitance and inductance measurement is described. It is based on an oscillator circuit with the oscillation frequency dependent on a measured element. An analysis of the oscillator used is also given. Equations for the oscillation frequency and its deviation from the resonance frequency of a frequency controlling resonance circuit are derived. The measured results can be transferred into a personal computer (PC) which can process and display these results and control the instrument via RS-232 serial interface.

Keywords: capacitance and inductance measurement, microcomputer control

J. Tavares, F. J. Velez, J. M. Ferro:

Application of Wireless Sensor Networks to Automobiles

Abstract:  Some applications of Wireless Sensor Networks (WSNs) to the automobile are identified, and the use of Crossbow MICAz motes operating at 2.4 GHz is considered together with TinyOS support. These WSNs are conceived in order to measure, process and supply to the user diverse types of information during an automobile journey. Examples are acceleration and fuel consumption, identification of incorrect tire pressure, verification of illumination, and evaluation of the vital signals of the driver.  A brief survey on WSNs concepts is presented, as well as the way the wireless sensor network itself was developed. Calibration curves were produced which allowed for obtaining luminous intensity and temperature values in the appropriate units. Aspects of the definition of the architecture and the choice/implementation of the protocols are identified. Security aspects are also addressed.

Keywords: wireless sensor networks, applications, MICAz motes, automobile, architectures, protocols

L.V. Finogenov, Yu.A. Lemeshko, P.S. Zav’yalov:

Using the Diffractive Optics for 3D Inspection of Nuclear Reactor Fuel Assembly Grid Spacers

Abstract: Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers fabricated as cellular structure with fuel elements. The required grid spacers’ geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using the diffractive optical element, which generates, as the structured light, a multiple-ring pattern on the inner surface of a grid spacer cell is investigated. The experimental measurement error for cell centers position deviation is ±7 µm, and the error for overall dimensions is ±11 µm.

Keywords: structured light method, diffractive optical element, fuel assembly, grid spacer

 No. 4

  Theoretical Problems of Measurement

78-81

P. Struhovský, O. Šubrt, J. Hospodka, P. Martinek:

A Virtual A/D Converter Testbench for Educational Purpose – Development and Results

Abstract: This paper deals with a new concept of virtual testing engine for analogue-to-digital converters (ADCs). The whole system consists of program procedures to extract the most important ADC errors expressed in terms of integral and differential non-linearity (INL and DNL). The developed testbench is especially suitable for educational purpose because of modular conception of the system. The proposed testing engine is implemented in Maple™, bringing an ideal possibility to make a complex system for the simulations of ADC at the virtual level as well as at the circuit level. The system is a part of a complex environment using the Servo-loop and the Histogram method, combining their features so as to obtain high level of versatility. However, in this paper we concentrate only on the results from the Servo-loop method. The Servo-loop solution proposed here employs an effective search algorithm and improves convergence properties resulting in a significant reduction of the simulation time.

Keywords: A/D Converter testing, behavioural modelling, Servo-Loop method, Integral and Differential Non-linearity

  Measurement in Biomedicine

82-86

V.K. Jayasree,  T.V. Sandhya, P. Radhakrishnan:

Non-invasive Studies on Age Related Parameters Using a Blood Volume Pulse Sensor

Abstract: A non-invasive technique is implemented to measure a parameter which is closely related to the distensibility of large  arteries, using the second derivative of the infrared photoplethysmographic waveform. Thirty  subjects within the age group of 20-61 years were involved in this pilot study. Two new parameters, namely the area of the photoplethysmographic waveform under the systolic peak, and the ratio of the time delay between the systolic and the diastolic peaks and the time period of the waveform (DT/T) were studied as a function of age. It was found that while the parameter which is supposed to be a marker of distensibility of large arteries and DT /T values correlate negatively with age, the area under the systolic peak correlates positively with age. The results suggest that the derived parameters could provide a simple, non-invasive means for studying the changes in the elastic properties of the vascular system as a function of age.

Keywords: vascular compliance, photoplethysmograph, systolic peak, second derivative

  Measurement of Physical Quantities

87-93

K. Kepa, D. Coburn, J. C. Dainty, F. Morgan:

High Speed Optical Wavefront Sensing with Low Cost FPGAs

Abstract: This paper outlines a study into deployment of a parallel processing scheme on an FPGA to meet the needs of high bandwidth processing in adaptive optics wavefront sensing. By exploiting a multi-stage pipeline approach we have significantly reduced the processing time needed to perform the wavefront sensing operation. The paper details the design, implementation, and performance testing results of the proposed FPGA-based wavefront sensing system.

Keywords: wavefront sensing, adaptive optics, FPGA, parallel processing

94-97

S. Bartkevičius, J. Novickij:

The Influence of Pulsed Magnet Heating on Maximal Value of Generated Magnetic Field

Abstract: The influence of pulsed magnet heating on the maximal value of the generated magnetic field is described. The operation of pulsed generator consisting of a capacitor bank, thyristor switch and wire wound pulsed inductor was analysed. The maximum value of the generated magnetic field and pulse duration of pulsed magnet was limited by Joule heating and mechanical stresses. Using Matlabâ Simulinkâ software, a flexible model for simulation of thermodynamic processes in pulsed magnet was developed. The calculated results of the maximal value and distribution of magnetic field were verified experimentally and  acceptable compliance was achieved using calibrated array of four pick up inductive coils for measurements of axial magnetic field and a current shunt for pulsed current measurements.

Keywords: pulsed magnetic field, wire wound magnet, Joule heating, pick up inductive coil

98-103

J. Hallon, M. Bittera, V. Smieško, K. Kováč:

Cabling Arrangement Influence on Repeatability of Immunity EMC Measurements.

Abstract: The paper deals with the analysis of induced current of differential loops of transmission lines during immunity test against electromagnetic field measurement. The influence of geometrical configuration of cabling arrangement on induced current values is surveyed. The problem is described for the case of a short two-wire line creating differential mode loop. The current induced at both ends of the line is the characteristics observed in the performed studies. The comparison between the results of measurements on real physical line, numerical simulations and analytical solution is presented.

Keywords: Electromagnetic compatibility, immunity testing, multiple transmission lines (MTL), influence of electromagnetic field, numerical simulation

104-107

D. Cerovecki, K. Malaric:

Microwave Amplifier Figure of Merit Measurement

Abstract: In this paper, the figure of merit of microwave amplifiers is measured. They are gain, 1 dB compression point and two tone third- order intercept products. The measurement setup as well as the method of measurement  are  shown. The measured amplifier can be used for student laboratory exercise as well as for appropriate scientific research.

Keywords: microwave amplifier, figure of merit, gain, third-order intercept point, 1db compression point

 No. 5

  Theoretical Problems of Measurement

108-110

I. Janiga, J. Mocak, I. Garaj:

Comparison of Minimum Detectable Concentration with the IUPAC Detection Limit

Abstract: Detection capability is an important performance characteristic of a measurement process. It is characterized by ISO as minimum detectable value. Another characteristic, used in chemical measurements, was defined by IUPAC as the limit of detection. These and further closely related characteristics are compared and theoretically analysed. Directions for their use are given and exemplified using chemical trace analysis of lead. 

Keywords: minimum detectable value, minimum detectable concentration, limit of detection, critical value, decision limit, limit of identification, limit of quantification

G. Wimmer jr.:

Statistical Method Based on Confidence and Prediction Regions for Analysis of Volatile Organic Compounds in Human Breath Gas

Abstract: In this paper we introduce two confidence and two prediction regions for statistical characterization of concentration measurements of product ions in order to discriminate various groups of persons for prospective better detection of primary lung cancer. Two MATLAB algorithms have been created for more adequate description of concentration measurements of volatile organic compounds in human breath gas for potential detection of primary lung cancer and for evaluation of the appropriate confidence and prediction regions.

Keywords: breath gas concentration, lung cancer detection, linear regression model, confidence interval, prediction interval

  Measurement of Physical Quantities

R. Šmíd, O. Číp, J. Lazar:

Precise length etalon controlled by stabilized frequency comb

Abstract: The progress in the field of optical frequency standards is oriented to femtosecond mode-locked lasers stabilized by technique of the optical frequency synthesis. Such a laser produces a number of coherent frequency components in certain interval of wavelengths. If we control the mode-locked laser by means of i.e. atomic clocks we ensure very stable frequency of these components. With respect to definition of SI unit ”one meter” on the basis of speed of light, the stabilized mode-locked laser can be used for implementation of this definition in a  non-traditional way. In the work we present our proposal of a system, which converts excellent frequency stability of components generated by the mode-locked laser to a net of discrete absolute lengths represented by a distance of two mirrors of an optical resonator.

Keywords: Fabry-Perot, interferometer, femtosecond, etalon

J. Hrabina, P. Jedlička, J. Lazar:

Methods for Measurement and Verification of Purity of Iodine Cells for Laser Frequency Stabilization

Abstract: We present an improved technique for detection of trace impurities in iodine-filled absorption cells for laser frequency stabilization. The results of purity investigation are compared to frequency shifts measured with a set of two iodine stabilized Nd:YAG lasers. The setup for direct fluorescence measurement with an Argon-ion laser operating at 502 nm wavelength is equipped with compensation for laser power and spectral instabilities.

Keywords: stabilized laser, saturated absorption, spectroscopy, iodine

A. Ondrášková, S. Ševčík, P. Kostecký, L. Rosenberg:

Simultaneous Measurements of Low-Frequency Natural Electric Field at Two Neighbouring Stations

Abstract: The electromagnetic eigenmodes of Earth-ionosphere global resonator known as Schumann Resonances (SR) are excited by global lightning activity. The simultaneous measurements of electric field in the ELF (~5 – 100 Hz) frequency band at two observatories clearly reveal the global character of the resonator response to the excitation both in the permanent Schumann background as well as in isolated events (transients). It is shown that measurement of ELF electric field can be done with  relatively simple equipment.

Keywords: Measurement of electromagnetic field, ELF frequency band, Schumann resonances, ionosphere

J. Pigošová, A. Cigáň, J. Maňka:

Thermal Synthesis of Bismuth-Doped Yttrium Iron Garnet for Magneto-Optical Imaging

Abstract: This contribution deals with the preparation and characterization of bismuth-doped yttrium iron garnets with composition BiY2Fe5O12 (Bi:YIG). The samples have been prepared by sintering of metal oxides homogenized in acetone for 10 minutes. The estimated average crystallite size of the single phase Bi:YIG synthesized at temperature 950 °C for 15 hours is ~ 65 nm.  The real content of Bi3+ cations in samples was quantitatively evaluated by application of real-coded genetic algorithm to the powder X-ray diffraction patterns.

Keywords: bismuth-doped yttrium iron garnet, synthesis, TGA/DTA, XRD, real-coded genetic algorithm

  Theoretical Problems of Measurement

Z. Domotor, V. Batitsky:

The Analytic Versus Representational Theory of Measurement:
A Philosophy of Science Perspective                                          Invited Article

Abstract: In this paper we motivate and develop the analytic theory of measurement, in which autonomously specified algebras of quantities (together with the resources of mathematical analysis) are used as a unified mathematical framework for modeling (a) the time-dependent behavior of natural systems, (b) interactions between natural systems and measuring instruments, (c) error and uncertainty inmeasurement, and (d) the formal propositional language for describing and reasoning aboutmeasurement results. We also discuss how a celebrated theorem in analysis, known as Gelfand representation, guarantees that autonomously specified algebras of quantities can be interpreted as algebras of observables on a suitable state space. Such an interpretation is then used to support (i) a realist conception of quantities as objective characteristics of natural systems, and (ii) a realist conception of measurement results (evaluations of quantities) as determined by and descriptive of the states of a target natural system. As a way of motivating the analytic approach to measurement, we begin with a discussion of some serious philosophical and theoretical problems facing the well-known representational theory of measurement. We then explain why we consider the analytic approach, which avoids all these problems, to be far more attractive on both philosophical and theoretical grounds.

Keywords: Gelfand representation, quantity algebra, state space, observables, measuring process, quantity conversion, quantity restoration

P. Otomański, A. Szlachta:

The Evaluation of Expanded Uncertainty of Measurement Results
in Direct Measurements Using the LabVIEW Environment

Abstract: The paper presents a possible application of integrated LabVIEW environment to the final evaluation of measurement results in direct measurement. The possibilities of presenting and visualizing the uncertainty of measurement results in a convenient and user-friendly form are also discussed. The topics presented in the paper were using the selected LabVIEW application.

Keywords: Expanded uncertainty, coverage factor, confidence interval, probability distribution, virtual instrument

A. Ghorbani, M. Mahmoodi Farahani, M. Rabbani, F. Aflaki, Syed Waqif hosain:

Uncertainty Estimation for the Determination of Ni, Pb and Al in
Natural Water Samples by SPE-ICP-OES

Abstract: In this paper we propose uncertainty estimation for the analytical results we obtained from determination of Ni, Pb and Al by solid-phase extraction and inductively coupled plasma optical emission spectrometry (SPE-ICP-OES). The procedure is based on the retention of analytes in the form of 8-hydroxyquinoline (8-HQ) complexes on a mini column of XAD-4 resin and subsequent elution with nitric acid. The influence of various analytical parameters including the amount of solid phase, pH, elution factors (concentration and volume of eluting solution), volume of sample solution, and amount of ligand on the extraction efficiency of analytes was investigated.  To estimate the uncertainty of analytical result obtained, we propose assessing trueness by employing spiked sample. Two types of bias are calculated in the assessment of trueness: a proportional bias and a constant bias. We applied Nested design for calculating proportional bias and Youden method to calculate the constant bias. The results we obtained for proportional bias are calculated from spiked samples. In this case, the concentration found is plotted against the concentration added and the slop of standard addition curve is an estimate of the method recovery. Estimated method of average recovery in Karaj river water is: (1.004±0.0085) for Ni, (0.999±0.010) for Pb and (0.987±0.008) for Al.

Keywords: Solid phase extraction, Amberlite XAD-4, inductively coupled plasma-optical emission spectroscopy (ICP-OES), Uncertainty

  Measurement of Physical Quantities

A. Koňakovský, A. Cigáň, J. Maňka, J. Bartkovjak:

Automatic Apparatus for Simultaneous Measurement of Resistance and Inductance Temperature Transition Dependences of Superconductors

Abstract: An automatic measurement complex for the study of transition properties of HTc superconductors using the transport method of the measurement of the resistance temperature dependence and the contactless mutual inductance method of the measurement of temperature dependence of the induced voltage based on the Meissner-Ochsenfeld effect have been developed. In addition, temperature dependences of harmonic components of the induced voltage may be measured simultaneously using the Brüel & Kjaer signal analyzer. Results of transport and induced voltage measurements are compared using YBCO superconductors with distinct grain and intergrain properties prepared by different technological procedures. The question of the mutual compatibility of such methods is discussed.

Keywords: high-temperature superconductors, transition characteristics, resistance method, mutual inductance method, harmonic response, critical temperature

 No. 1   No. 2   No. 3   No. 4   No. 5   No. 6

  Journal is open for your papers

 Download and print the front cover  ->>