Looking at the current status of hardness standards, we occasionally come across the view that it is sufficient that hardness measurements can be matched somewhat forcibly to the hardness values of standard blocks. However, if the direct accuracy of a hardness tester and indenter and loading conditions are well managed and appropriate testing procedures are taken, the measurement of hardness should naturally agree with the value indicated on a standard block, and “hardness” should be an industrial quantity obtained in that way. Therefore, we should recognize anew the original purpose of a hardness standard block as a standard tool, such as the daily inspection (indirect verification) of a tester and/or whether testing practices are under proper management, as well as to make a comparison between testers and/or between indenters.
From this standpoint, we, in the capacity of a dedicated test-block manufacturer, discuss the principles of hardness test methods, the uniformity, durability and trends of hardness standard blocks, and future hardness standards relative to the ISO standards, based on our past results from testing and experiments with a number of standard blocks.

Standard Rockwell diamond indenters play an important role for a worldwide unified Rockwell hardness scale. In 1994, the National Institute of Standards and Technology (NIST) established a Microform Calibration System with sufficiently small calibration uncertainty for the calibration of standard Rockwell indenters. In 1995, NIST established a group of Rockwell diamond indenters characterized both by high geometrical uniformity and hardness performance uniformity. One of them, No. 3581, was selected as the NIST’s primary Rockwell diamond indenter for the calibration of NIST’s Standard Reference Material (SRM) Rockwell C hardness blocks. This indenter was recalibrated in 1997 and 2005. The calibration results showed high stability for the microform geometry of the NIST’s standard Rockwell diamond indenter, as well as high calibration reproducibility for the NIST’s Microform Calibration System.

The paper describes theoretical design and simulation results of the high precision amplifier for use in metrology especially for measurement of low AC voltage in a wide frequency range. The whole device will be used in process of calibration of common multimeters with AC/DC comparation technique.

This work presents the system performance analysis, in terms of frequency response and system resolution, of a 1-bit first-order Σ-&Delta thermal modulator. In this system model, some of the operations conversion is performed by the thermoresistive sensor, which operates at constant temperature method. The system performance analysis was realized with a sampled version of the continuous time thermal Σ-&Delta modulator. It will be shown that system performance is dependent on the system oversampling ratio (OSR) and the system transfer function pole and zero which depends on thermal and physical sensor characteristics and system operation conditions. This system was proposed as a solar radiation meter, but it may be applied to fluid velocity measurement.

The Perceived Power Quality by costumers has been faced, starting from ISO 9000 Quality definition. An experimental investigation is presented on customers of Rome (Italy). By the results one demonstrates that fluxes of parameters defined on own manner by costumers, can be determined.