Lovorka Grgec Bermanec

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• Professor
• Professor (Full) at University of Zagreb

This paper describes two methods for measurement of air pressure inside the saturation chambers of two primary dew/frost point generators, used as national humidity standards at Laboratory for process measurement (HMI/FSB-LPM) in Croatia. Together, the generators cover the dew/frost point temperature range from −70 °C to + 65 °C. Low range generato...

Bilateral comparison was organized between the laboratory for process measurement of the Croatian Metrology Institute (HMI/FSB-LPM) and the pressure laboratory of the Directorate of Measures and Precious Metals of the Republic of Serbia (DMDM). Laboratory for process measurement of HMI acted as the pilot laboratory. The aim of the comparison was to...

This paper describes development of gas pressure scale up to 18 MPa using dimensional and cross-float experiments in Croatian national pressure laboratory (HMI/FSB-LPM). Practical pressure scale for gas as transmitting medium is realised using a group of six gas-operated-piston-cylinder assemblies and diving bell manometer. For more than 15 years,...

This paper describes laboratory method for experimental determination of the pressure balance piston and cylinder coefficients of thermal expansion (CTE) using interferometric technique with internally developed software. Measurements were carried out on one gas standard piston/cylinder units in the Croatian National Length (HMI/FSB-LPMD) and Press...

It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow a link to the CCM.P-K6 and CCM.P-K2 comparisons to be established. This project interested a lot of laboratories from the beginning with 23 participants, 22 of which have submitted results. The circulat...

This paper describes the development and validation of an apparatus for the realization of the triple point of argon (83.8058 K), with a novel automatic pressure control system for the liquid nitrogen cryostat. The automatic pressure controller, together with custom-made software, was developed and tested in the Laboratory for Process Measurement a...

Low-frequency working standards of inductance are generally uniformly wound toroids on a ceramic core. Planar inductors made using printed circuit board (PCB) technology are simple and cheap to manufacture in comparison to inductors wound on toroid cores, but they are significantly prone to the influence of external magnetic fields. In this paper,...

This paper investigates accuracy, influence of temperature variations and time drift of water level data loggers, operating on a principle of hydrostatic pressure measurement. The laboratory setup for calibration of such devices, equipped with self-designed pressure chamber and commercial climatic chamber is presented. Calibration procedure for log...

The regional supplementary comparison EURAMET.M.P-S13 for pressure measurements in liquid media from 10 MPa to 100 MPa was piloted by the TÜBİTAK UME Pressure Laboratory, Turkey. The transfer standard was a digital pressure gauge, serial number 116321, manufactured by Paroscientific Inc. Eighteen laboratories participated in this comparison. Fourte...

A EURAMET key comparison of the national pressure standards in the range 0.7 MPa to 7.0 MPa of gas gauge pressure was carried out. The circulation of the transfer standard began in November 2011 and lasted until November 2016. The measurand of the comparison was the effective area of the piston-cylinder assembly determined by gauge pressure measure...

The purpose of this paper is to provide insight into the distributed nature of the Croatian metrology institute (HMI) as well as basic past and present circumstances in Europe that led to the adoption of this concept. The HMI structure and it's designated institutes (DIs) are described. The requirements for HMI-DIs and process of their selection ar...

This paper presents a new experimental method and algorithm for the determination of self-heating of platinum resistance thermometer (PRT) when the temperature instability of medium of interest would prevent an accurate self-heating determination using standard methods. In temperature measurements performed by PRT, self-heating is one of the most c...

A comparison in the negative gauge pressure range was arranged in the period 2011 - 2012. A total of 14 laboratories participated in this comparison: BEV (Austria), CMI (Czech Republic), DANIAmet-FORCE (Denmark), EIM (Greece), HMI/FSB-LPM (Croatia), INM (Romania), IPQ (Portugal), LNE (France), MCCAA (Malta), METROSERT (Estonia), MIKES (Finland), MI...

This paper describes procedure and results of the interlaboratory comparison that was organised by Croatian national pressure laboratory (HMI/FSB-LPM) between eight accredited pressure calibration laboratories. Comparison was performed in the gauge pressure range from 0 to 2 MPa with pressure transducer as transfer standard and using gas as transmi...

p>This paper describes a laboratory method for the determination of the pressure balance piston fall rate using a simple camera-based optical system with internally developed software. Measurements were carried out on three standard piston/cylinder units in the Croatian National Pressure Laboratory (LPM) using gas and oil as transmitting medium. Me...

Fifteen European metrological institutes have compared their approaches to estimate the effec-tive area parameters resulting from the calibrati-on of pressure balances by cross-floating. The methods in estimating these parameters and the associated uncertainties are tested by applying four calibration data sets simulated numerically, two in gas (up...

This article describes the realization of the International Temperature Scale in the range from 234.3K (mercury triple point) to 1084.62°C (copper freezing point) at the Laboratory for Process Measurement (LPM), Faculty of Mechanical Engineering and Naval Architecture (FSB), University of Zagreb. The system for the realization of the ITS-90 consist...

This paper presents characterization of diving-bell manometer in the gauge pressure range from -1.0 up to 3.0 kPa in the Croatian national pressure laboratory -Laboratory for Process measurement (LPM), located at the Faculty of Mechanical Engineering and Naval Architecture (FSB), University of Zagreb. The work points out comparison of two independe...

Bell provers are in most cases primary standards in flow laboratories. They operate in a lower flow range (usually up to 100 m3/h) depending on the size of the bell and are widely used for calibrating various types of flow meters. The volume generated by the bell can be determined with some measurement uncertainty by the area of the bell and the me...

This paper describes characterization of 1-T dew point generator developed at Laboratory for Process Measurement (LPM) self-. Present operating range of generator is from -7°C to 18°C dew point range. The air flows through saturator in closed loop and is contr olled with regulated flow meters. Air saturation degree is det ermined by measuring the t...

The objective of this paper is to present the methodology for estimation of measurement uncertainties in comparison calibration of thermocouples used in Croatia at the Laboratory for Process Measurements (LPM) and in France at the Bureau National de Métrologie (BNM). The methodology is applied for comparison calibration of rare-metal and industrial...

This paper describes an iterative methodology for calculation of surface temperature measurement errors applied to symmetrically heated, vertical parallel-plate channels. Heat transfer calculations within the channel (marching, control-volume based, numerical procedure) are first based on initial raw and uncorrected surface temperature measurements...

This paper presents a simplified model for the evaluation of the measurement uncertainty of pressure balance effective area calibrated by method of comparison which is being applied at Laboratory for Process Measurements (LPM). The methodology is applied for oil- operated industrial pressure balances in the gauge pressure range up to 60 MPa. The sc...

The objective of this paper is to present the methodology for estimation of measurement uncertainties in comparison calibration of thermocouples used at Laboratory for Process Measurements (LPM). The methodology is applied for comparison calibration of rare-metal and industrial base-metal thermocouples within temperature range from -20°C to 660°C w...

This paper presents th test system and methodology for NDT and characterisation of gas pressure sensors in the gauge pressure range of 0.015 bar to 2 bar developed in the Laboratory for Process measurement (LPM) at the Faculty of Mechanical Engineering and Naval Architecture (FSB) in Zagreb. The design of the system, theoretical basics, main parame...

This paper presents absolute pressure calibration system in the range from 25 kPa up to 2 MPa which is being developed in Croatian national pressure laboratory- Laboratory for Process Measurement (LPM) at Faculty of Mechanical Engineering and Naval Architecture (FSB) in Zagreb. Design of the system, theoretical basis, effective area determination m...