9762 papers found
This paper presents the needs in Mexico for larger ranges in torque calibration. The design of a torque standard to meet, and surpass, those needs are here included. The general design considerations, the layout of the system and the subsystems designed for the torque national standard for 20 k·Nm in Mexico are discussed and included in this paper.
JCSS is an accreditation system operated by IAJapan (International Accreditation Japan) in line with ISO/IEC 17025 as accreditation criteria. This paper introduces our latest investigation of JCSS, MRA (Mutual Recognition Arrangement) for Laboratory Accreditation, Tendency of its activities and Requirements of its users.
This paper describes measurement of resultant acceleration of motion and gravity in 3D space based on sensing a metallic ball position on elastic layer housed in a spherical shell. Construction of different types of silicon rubber is introduced and their displacements against pressure are calculated by using the Hertz' law. Since the resultant acceleration makes the ball roll toward the direction to find a balanced position in the shell, the center position of the metallic ball is measured. The rubber layer is concentric to the shell and liable to distort so that three proximity sensors of...
The purpose of this study was to investigate differences in brain activation by electrotactile stimulation of two fingers of the right hand with different frequencies using fMRI. Non-painful electrotactile stimuli were delivered. Significant activation produced by the stimulation were found in the SI, SII, subcentral gyrus, precentral gyrus, and insula. In all participants statistically significant activation was observed in the contralateral SI area and bilateral S? areas by the stimulation on the fingers but ipsilaterally dominant. The SI area representing the second finger generally...
The continuous calibration method of force transducer represents a very helpful method since the calibration can be carried out in a short time compared with the step by step method. Another advantage of the continuous calibration method is the possibility of recording the responses of the standard force transducer and the force transducer to be calibrated synchronously. This could be done using two different channels of the displaying device. The disadvantage of this method is the difficulty to define exactly constant certain loads at each loading series during the calibration. The...
Any electronic balance has more or less nonlinearity. This paper presents a method to correct and check the nonlinearity by using two sets of lower class weights. Some of the key causes of the nonlinear error are described first. Common-meet parabola nonlinear pattern were studied in detail. A correcting procedure, using a set of lower class or even no class weights is then described. The correcting coefficient is given in the paper in an apparent form. Simulation and test results showed the nonlinear error reduced dramatically with the method. A check process is required before a balance...
This article is concerned with the use of counterrotating mechanical bearings in torque calibration sys- tems. First a short overview on some general aspects of this bearing type will be given, which includes a general description of their construction as well as of their functionality. The main section deals with experimental examinations made on the performance of counterrotating bearings. These experiments were completed mainly using the horizontally arranged MIKES-RAUTE 2 kN·m torque standard calibra- tion device. Additionally initial results gained with the new vertically arranged 20...
A new design of primary torque standard machines (TSM) with feedback-control of the lever support was described at IMEKO – XVI World Congress in Vienna [1]. The purpose of this paper is to present the performance of a hand operated option model in the wide range from 2 N·m up to 3000 N·m. Influences of hand operation are estimated as well as ambient influences like temperature changes and air flow. A protection chamber against the ambient influences was built and the improvement is shown. The TSM has three mass stacks to cover all transducer capacities from 20 N·m up to 3000 N·m in each ten...
For the determination of the local gravity high precise mobile gravimeters are in use since more than a hundred years. As a result of the basic measurement principle the determination is carried out point-by-point with the consequence that the procedure is time consuming and expensive. Thus in many countries the results of several measurement campaigns have been collected over decades. Whereas the measured values are available to the public only to some extent, the data were of- ten processed to gravity anomaly maps for the purpose of geological ground surveys. In this research two samples...
A group of nine calibration laboratories performed an intercomparison of Conventional Mass in 2004. The comparison consisted of conventional mass for four weight pieces, namely 100 g, 10 g, 100 mg and 2 mg. All participating laboratories are accredited for this measurement. However, they are distributed around the world on different continents, they are accredited under different accreditation bodies and are traceable to different national standards. This is special, as usually calibration laboratory intercomparisons are performed in one country only or among laboratories that are accredited...