9762 papers found
Primary task of the mass calibration laboratory is dissemination of mass unit to its multiplies and submultiplies. Due to the buyoancy force the volume of the mass standards have to be known prior to the measurements. The method presented in this paper allows determination of mass and volume separately. Using right devices it is possible to perform all measurements in one experiment.
A 20 kN·m torque standard machine has been designed and developed at National Institute of Metrology (NIM) since 2012. The torque standard machine adopts the lever-deadweight type, the air bearing with low friction is adopted to support the arm lever at the fulcrum, the invar alloy with the low expansion coefficient is used as the material of the arm lever, the weight suspension part and weight loading system are specially designed to ensure the force generated by the weights is applied accurately and reliably. 20 kN·m torque standard machine is capable of realizing the torque from 100 N·m...
Usual subdivision methods are working excellent in the absence of outliers. On the other hand a small number of outliers can lead to complete wrong estimates. Several general methods are used for robust linear regression, but these methods are not used for improving the subdivision yet. The new approach which can be classified as an iteratively reweighted least square method with special weight-functions introduced in BEV provides efficient robust results by downgrading the outliers.
Axle weighing system measures axle weights of in-motion vehicles. Methods have been studied for estimating axle weights by processing the weight signal to improve the accuracy of measured axle weights. The examination of the accuracy of estimated axle weights of in-motion vehicles with higher velocity has not yet completed. To examine and improve the accuracy of the estimated axle weight, miniature models have been developed. The method have been applied to the obtained weight signals. This paper presents the developed miniature models and application results of the method.
This paper discusses behaviors of a high speed mass measurement system. The goal of this paper is to propose a simple dynamic model of the system. The dynamics of the system with electro-magnetic force compensation is approximated by a mass-spring-damper system, and an equation of motion is derived. Model parameters are estimated from experimental data. Then, comparisons of the simulation results with the realistic responses are carried out. Finally, effects of floor vibration are explored.
A new torque calibration machine with a torque capacity of 5 kN·m has been installed in Force and Pressure Laboratory of GUM. This reference type machine generates torques in vertical axis in a range from 10 N·m to 5 kN·m with an expanded relative measurement uncertainty of 0,04 % ( k = 2). Performance of the machine has been evaluated via comparison between GUM and PTB. Results of comparison measurement are presented.
Build-Up systems (BU systems) are parallel combinations of force transducers for realizing a large range of rated loads using one type of transducer. As yet there is no uncertainty budget for these devices. Creating such, makes it necessary to detect the significant influencing parameters of BU systems by measurements and to prepare appropriate methods for the processing of the collected data. This paper will regard this processing.
This paper describes the constructional details of an FEM-supported construction of adaptation parts for a Build Up system up to 15 MN. After a short introduction about “Ukrmetrteststandard”, the NMI in Ukraine, several constructional details will be discussed which result in a very low measurement uncertainty. In addition, some experiences about the use of BU systems obtained during the evaluation will be presented.
A force comparison was carried out among various laboratories from Inter American System (SIM), in order to estimate the level of agreement for the realization of the quantity and the uncertainty associated to its measurement. The comparison was carried out in the ranges of 50 and 100 kN in compression. In order to achieve best accuracy of the force transducer the measurement range started in 50% of the maximum transducer range. The results obtained, the deviations graphs that include the uncertainty for each laboratory are presented in this document.
Recent advance in flow metering of electrolytes through contactless method of Lorentz Force Velocimetry (LFV) demands application specific developments of high precision horizontal force measurement systems. In contrast to the measurand Lorentz force- directed horizontally and ranges as 10 -8 - 10 -5 N - there is 10 N vertically acting dead load accompanying measurements. In this work we present overview of two force measuring setups resolving these measurements particularly suitable for metering flow velocity of purely conducting liquids in channels. The first setup is based on principle of...