ABSTRACT. Non-contact DC meters have been developed. To study them, the optimal by cost experimental designs were synthesized. As a result of contactless DC meters experimental research - polynomial mathematical models were obtained. Based on the mathematical models, the optimal design parameters for the DC meters were gained, providing a minimum measurement uncertainty.

ABSTRACT. The carbonation of concrete and chloride ions in it affect on the durability and proper functioning of reinforced concrete structures. They contribute to the faster corrosion of the reinforcement. In this paper is experimentally investigated the actual state of 12 reinforced concrete beams at age of 1926 days from their preparation. They are loaded on bending till the yielding of the longitudinal reinforcement or till loading stage before the yielding, corresponding to a maximum crack width of 0.3 mm. Then the reinforced concrete elements were indoors for two years and after that subjected to external atmospheric influences for three years. For assessing the state of the beams destructive and non-destructive methods for control have been used. The chloride ion penetration is determined by measuring the surface specific electrical resistance of the concrete with a 4-point Wenner probe with instrument ResiPod Family of the company Proceq. The carbonation depth of concrete is determined on concrete cores that have been taken from the reinforced concrete beams. The cores were treated with a solution of 1% phenolphthalein in alcohol according to EN 14630: 2007.

ABSTRACT. In this paper are described the experimental studies performed for determining the structure, assessing the defects and imperfections in the surface and inside of cored specimens, taken from reinforced concrete elements at age of concrete 1926 days. A contactless non-destructive tomographic method was used. Two- and three-dimensional images were obtained. Studies have been made at different depths of rays penetration. Device Nikon XT-H 225 was used. Data processing was performed with the software Volume Graphics, MyVGL. The carbonation depth of the concrete has been determined.

ABSTRACT. The importance of accurate fuel quantity measurement has gradually increased for its impact on range prediction. Available vehicle fuel measurement systems are only able to give inconclusive fuel level estimation. Vehicle fuel range anxiety on drivers is probably pushing researchers to present different measurement techniques, to improve on the status quo. This paper presents an integrated fuel quantity measurement technique, which is based on the segmented reed trigger points of a known fuel tank capacity, for continuous fuel density monitoring and the available fuel weight measurement. The technique gives accurate fuel quantity, as it accommodates fuel density variations, while eliminating the effects of fuel sloshing.

ABSTRACT. A novel silicon Hall device with geometry-enhanced sensitivity was fabricated and characterized. The magnetosensitivity was grows with the charge carrier density on the Hall sides. The shape of the edges on which the Lorentz force deflects the electrons has the form of isosceles acute triangles on whose corners the ohmic Hall contacts are formed. The sensors were realized based on n-Si wafers with ρ ≈ 7.5 Ω.cm. The obtained transducer efficiency is by about 20 % higher than the sensitivity of the usual with orthogonal activation Hall element from the same material and with the same input conditions. The new Hall configuration is very promising for low-field magnetometry and robotized surgery.

ABSTRACT. The paper presents the hardware and software part of the developed virtual measurement system for automatic recording of the change of the temperature change from multiple transducers. An algorithm of the working process of the virtual measurement system is shown.

ABSTRACT. The project 18PRT03 MetForTC “Traceable measurement capabilities for monitoring thermocouple performance” funded by the EMPIR programme is presented in this article. The general aim of this project is to develop novel scientific and technical capabilities providing both the dissemination of the International Temperature Scale of 1990 (ITS-90), which is an important in both developed and emerging NMIs, and accurate temperature measurements by thermocouple and low uncertainty. This objective will be achieved by developing novel practical methods and devices (such as dual-type thermometers) for checking thermocouple drift performance in-situ and easy-to-use integrated miniature cells to determine the inhomogeneity of thermocouples for primary and secondary calibration laboratories.

ABSTRACT. Calibration of a household water meter is described in EA-4/02 (S12). A feature of this problem is the nonlinear model equation, a large number of input quantities and the presence of significant uncertainty associated with poor repeatability of measurements. This makes it difficult to evaluate the expanded measurement uncertainty at calibration. The report describes the application of the kurtosis method, which allows automating the process of determining the coverage coefficient for given distribution laws of input quantities. In addition, the effect of the significance of non-linearity of the model equation on the accuracy of estimation of measurement uncertainty is checked. The results obtained are compared with the results evaluated by the Monte Carlo method and show good agreement.

ABSTRACT. The project 18RPT01 ProbeTrace “Traceability for contact probes and stylus instruments measurements” funded by the EMPIR program part of Horizon 2020 of the EU is presented in this article. The project aims is to develop traceable and cost effective measurement capabilities for the calibration of form and surface roughness standards. This project will improve the scientific knowledge, instruments, methods and research capability in metrology for contact measurement probes and stylus instruments and enable particularly the new NMIs to develop new capabilities for self-provision of the traceability to SI unit, metre.

ABSTRACT. В доклада се разглежда измерването на дължината на общата нормала W чрез специализирано микрометрично средство за измерване в условията на тежкото машиностроене. Обоснована е необходимостта от подобрение на специализирано микрометрично средство за измерване при контрол на W и са представени резултатите от емпиричното изследване.

ABSTRACT. The paper presents the results of the study of the structure and composition of new ferromagnetic materials, performed with an automated system for complex non-destructive testing of the structure and mechanical properties of samples and articles of metal materials MULTITEST. It consists of several modular devices that measure one or two non-destructive information parameters based on methods with different physical foundations (magnetic, ultrasonic and thermoelectric). Three optimized modular devices of the system are presented: MULTITEST-MC010 for research of ferromagnetic materials with the methods for measuring the magnetic noise and the magnetoacoustic emission of Barkhausen, MULTITEST-CD010 for research of machine-building materials with the methods for measuring speed and attenuation of ultrasound and MULTITEST-TE010 for measuring the thermoelectric power in metallic materials. The main approaches for the optimization of the automated data processing from measurement / test and the adjustment of the modular instruments are presented, by applying the graphic program LabVIEW. The possibility for the application of these methods for complex non-destructive testing of the structure and composition in samples of sintered materials for permanent magnets, samples of amorphous alloys and samples of active cathode materials for application in EV / HEV vehicles is shown. It has been proved that the non-destructive information parameters - magnetic noise voltage and magnetoacoustic emission voltage depend on the structure and composition of the studied amorphous alloys and cathode materials, and the non-destructive information parameters speed and attenuation of ultrasound in the controlled material depend on the structure and composition of the neodymium magnets. The non-destructive information parameter of the method for measuring the thermoelectric force - thermoelectric voltage can be used as an additional parameter in many cases in complex non-destructive testing - for example in amorphous alloys and permanent magnets.