9762 papers found
The centre of the weight need to be measured to correct the difference between centers of the test weight and the reference weight for high precise mass measurement, and a device is developed to locate the centre of the weight which includes a balance, a bridge and a supporting pole. A measuring method was proposed in [1]. A revised method is discussed in this paper and the effectiveness of the method is shown by measurements.
Torque wrenches are commonly used measuring instruments in many applications. They are calibrated on torque wrench calibration devices. In Germany, at least in the accredited laboratories, the latter are calibrated using precision torque transfer wrenches and applying the corresponding DKD calibration guideline. This guideline was recently revised. The main new ideas and modifications will be presented in this paper.
Subdivision comparisons of mass measurement are usually used in the mass dissemination for class E1 and E2 mass standards from 1 kg to 1 mg or from 1 kg to 50 kg. Many equations of mass measurement are included in the subdivision comparisons. It is not easy to calculate values of true mass or conventional mass and the budget the uncertainty of subdivision comparisons by hand or Microsoft Excel software. Matrix calculations used in the subdivision comparisons of mass measurement are very convenient to get the true mass value or conventional mass value of every weight compared. Due to some...
Surface analytical model is presented to observe the adsorption. Mass standards with special shapes are difficult to design due to complex parameters. Method based on self-adaptive algorithm is given out to help designing the best sorption artefacts. This algorithm helps to design best shape of cylinder-weight and stack-weight that are with same volume and different surface area.
When we need to calibrate a force transducer, we usually refer to ISO 376. This standard considers hysteresis as an error included into the uncertainty budget. The objective of this paper is to provide laboratories with tools to estimate the hysteresis. The measurements procedure, the methodology to extract the hysteresis while empowering the zero drift and non-linearity of the calibrated transducer, the modelling and the correction of its effect are proposed.
A noncontact test method for the volume determination of weights from (1 to 1 000) g is described. The method uses an optical comparator to size cylindrical weights, and allows to compute the volume of the weight according to OIML R 111-1 Method E. The volume values obtained for the weights were compared against hydrostatic weighing volume results for reference. The volume relative uncertainty levels reached with the optical comparator are small enough for calibration operations of even OIML Class E 2 weights.
A deadweight force standard machine is a mechanical structure that generates force by subjecting deadweights to the local gravitational field. Korea Research Institute of Standards and Science (KRISS) maintains several deadweight force machines for national force standards. KRISS is developing a 1 MN deadweight force standard machine. The project is scheduled to be finished in 2015. This paper describes the concept and structure of the force machine. The manufacturing and installation of the force machine are also described in this paper.
We changed a new 10-kg mass comparator with automatic load alternator at CMS (Center for Measurement Standards) last year to replace the older one which was out of function. During installation, the temperature issue comes out to affect the measurement results under the same environment of laboratory as usual. In this paper, we will discuss the abnormal phenomenon caused by the thermal effect.
Force transducers are usually used by national and accredited laboratories to calibrate force generated systems. Laboratories own several load cells to carry out calibrations, this forms an over cost for purchasing several load cells. One way to solve this problem is introducing a force transducer with different capacities. This article summarizes the achievements of proposing an economical force transducer with three different capacities works in compression mode.
A new multi-component facility for force and torque, which can simultaneously realize precise axial force ( F z ) and torsional moment (torque, M z ), is being developed in PTB. Moreover, precise two-axis measuring devices (force-torque transducers) as transfer standards must be also developed for the establishment of the measurement traceability of screw testing machines. Authors have calibrated a new-developed force-torque transducer in each direction of force and torque, separately. The crosstalk matrixes have been obtained by ordinal way, where the normal square-inverse matrix (2 by 2)...