A balance is proposed, which allows the calibration of weights in a continuous range from 1 mg to 1 kg using a fixed value of the Planck constant, h. This so-called Planck-Balance (PB) uses the physical approach of Kibble balances that allow the Planck constant to be derived from the mass. Using the PB no calibrated mass standards are required during weighing processes any longer, because all measurements are traceable via the electrical quantities to the Planck constant, and to the meter and the second. This allows a new approach of balance types after the expected redefinition of the SI-units by the end of 2018. In contrast to many scientific oriented developments, the PB is focused on robust and daily use. Therefore, two balances will be developed, PB2 and PB1, which will allow relative measurement uncertainties comparable to the accuracies of class E2 and E1 weights, respectively, as specified in OIML R 111-1. The balances will be developed in a cooperation of the Physikalisch-Technische Bundesanstalt (PTB) and the Technische Universität Ilmenau in a project funded by the German Federal Ministry of Education and Research.
Lorentz force velocimetry is a non-invasive velocity measurement technique for electrical conductive liquids like molten steel. In this technique, the metal flow interacts with a static magnetic field generating eddy currents which, in turn, produce flow-braking Lorentz forces within the fluid. These forces are proportional to the electrical conductivity and to the velocity of the melt. Due to Newton's third law, a counter force of the same magnitude acts on the source of the applied static magnetic field which is in our case a permanent magnet. In this paper we will present a new multicomponent sensor for the local Lorentz force flowmeter (L2F2) which is able to measure simultaneously all three components of the force as well as all three components of the torque. Therefore, this new sensor is capable of accessing all three velocity components at the same time in the region near the wall. In order to demonstrate the potential of this new sensor, it is used to identify the 3-dimensional velocity field near the wide face of the mold of a continuous caster model available at the Helmholtz-Zentrum Dresden-Rossendorf. As model melt, the eutectic alloy GaInSn is used.
In this paper, we present an application for realizing high-precision horizontally directed force measurements in the order of several tens of nN in combination with high dead loads of about 10 N. The set-up is developed on the basis of two identical state-of-the-art electromagnetic force compensation (EMFC) high precision balances. The measurement resolution of horizontally directed single-axis quasi-dynamic forces is 20 nN over the working range of ±100 μN. The set-up operates in two different measurement modes: in the open-loop mode the mechanical deflection of the proportional lever is an indication of the acting force, whereas in the closed-loop mode it is the applied electric current to the coil inside the EMFC balance that compensates deflection of the lever to the offset zero position. The estimated loading frequency (cutoff frequency) of the set-up in the open-loop mode is about 0.18 Hz, in the closed-loop mode it is 0.7 Hz. One of the practical applications that the set-up is suitable for is the flow rate measurements of low electrically conducting electrolytes by applying the contactless technique of Lorentz force velocimetry. Based on a previously developed set-up which uses a single EMFC balance, experimental, theoretical and numerical analyses of the thermo-mechanical properties of the supporting structure are presented.
An experimental setup for performing micro-scratching tasks and measuring the forces involved in the process is presented in this paper. The main component of the system is a multi-component force and torque sensor based on the principle of electromagnetic force compensation (EMFC). With this device it is possible to perform the micromachining process itself while simultaneously measuring the interaction forces between the tool tip and the test specimen. Experiments were performed with specimens of polished steel, silicon and glass. Planar micro-structures could be produced and tool point interaction forces in the order of some millinewtons were measured during the process.
Multi-component force/torque transducers are used in a large field of scientific and industrial applications like robotics, biomechanics and even fluid mechanics. These sensors need to be calibrated for traceable measurements. As the calibration procedure determines the measurement uncertainty, it plays an important role in sensor development for reaching the required measurement specifications. For the application in local Lorentz Force Velocimetry (Ref. 1) a six degree of freedom force/torque sensor for measurement ranges of ± 0.2 N and ± 5 mNm was developed. This sensor can also be adapted to other applications that require multi-dimensional force/torque feedback in the µN-and µNm-range such as tactile dimensional measurements and micro-manipulation. This paper discusses the calibration and the evaluation of the properties of the calibration device and the calibration procedure of the sensor system. After a brief introduction of the sensor design and its working principle the calibration setup is described and the uncertainty contributions to the forces and torques are calculated. Then the calibration procedure is presented and the resulting output signals of the sensor are depicted. As a result of the calibration, the calibration matrix is given with a discussion of its major components.
A multi-component self-calibrating force and torque sensor is presented. In this system, the principle of a Kibble balance is adapted for the traceable force and torque measurement in three orthogonal directions. The system has two operating modes: the velocity mode and the force/torque sensing mode. In the velocity mode, the calibration of the sensor is performed, while in the force/torque sensing mode, forces and torques are measured by using the principle of the electromagnetic force compensation. Details about the system are provided, with the main components of the sensor and a description of the operational procedure. A prototype of the system is currently being implemented for measuring forces and torques in a range of ±2 N and ±0,1 Nm respectively. A maximal relative expanded measurement uncertainty (k=2) of 10•10-5 is expected for the force and torque measurements.
Translation of the Bible or any other text unavoidably involves a determination about its meaning. There have been different views of meaning from ancient times up to the present, and a particularly Enlightenment and Modernist view is that the meaning of a text amounts to whatever the original author of the text intended it to be. This article analyzes the authorial-intent view of meaning in comparison with other models of literary and legal interpretation. Texts are anchors to interpretation but are subject to individualized interpretations. It is texts that are translated, not intentions. The challenge to the translator is to negotiate the meaning of a text and try to choose the most salient and appropriate interpretation as a basis for bringing the text to a new audience through translation.
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