IMEKO Event Proceedings

Page 8 of 822 Results 71 - 80 of 8218

Luca Callegaro, Jan Vejdelek
A Bridge for High-frequency Capacitance Scaling

A bridge, suitable for 1:1 and 10:1 ratio measurements of four terminal-pair impedances to frequencies up to 5 MHz, has been constructed and is presently under testing. The purpose of the bridge is to extend the Italian national standard of capacitance toward higher frequencies; however, the bridge will be employed for resistance comparisons also. Expected best uncertainty is in the order of a few parts in 10-5 for 10 nF - 1 nF ratio measurements, at 1 MHz.

Vadim Geurkov

Signature analysis techniques have become extremely popular in digital systems testing due to such advantages as simplicity, small amount of additional circuitry, and small degree of error masking. In this paper the signature analysis techniques are applied to mixed (analog-to-digital) systems testing. The general case of multi-channel measurement system is considered.

G. Kok, N. Pelevic, A. Chiribiri, X. Milidonis, M. Nazir, M. Capstick, S. Drost, C. Poelma, T. Schaeffter
A calibrated physical flow standard for medical perfusion imaging

In the medical sector, various imaging methodologies or modalities (e.g. MRI, PET, CT) are used to assess the health of various parts of the bodies of patients. One such investigation is the blood flow or perfusion of the heart muscle, expressed as the (blood) flow rate normalized by the mass of the volume of interest, with unit mL/min/g. Currently there is no physical flow standard for the assessment and validation of myocardial perfusion imaging methodologies, resulting in a large proportion of medical diagnoses being inaccurate and highly dependent on the scanner type, software used and the clinical operator. In the EMPIR 15HLT05 PerfusImaging project a phantom simulating myocardial perfusion has recently been developed with which imaging modalities can be tested. In this paper the construction and validation of the phantom is described which involved several iterations with design updates, computational fluid dynamics simulations, 3D printing of the phantom, ultrasound imaging velocimetry and magnetic resonance imaging (MRI). Dynamic contrastenhanced MRI was performed to image the passage of a tracer through the phantom and estimate perfusion. Two flow models and associated data analysis methods to relate the measurement data with the reference flow rates are presented and discussed.

Andrzej Miekina, Roman Z. Morawski

The spectrophotometric analysis of oil mixtures, containing olive oil, is the subject of this paper. Its objective is to propose and evaluate a new methodology for determination of a selected component of such a mixture. According to this methodology, the space of concentration values to be estimated is partitioned into subspaces and the calibration is performed separately for each subspace by means of a new piecewise ridge least-squares estimator. The estimation of concentrations is carried out, using the results of calibration, in two cycles: first, rough estimates of concentrations are found and a corresponding subspace is identified; next, the results of calibration, obtained for this subspace, are used for refining the estimates of concentrations. The performance of the proposed methodology is assessed using a criterion related to measurement uncertainty.

T. Dunker, S. Sperling

We consider measuring machines (MMs), which use one ore more 2-D laser sensors (2-DLSs) for automated dimensional inspection. In order to transform several measurements from their sensor coordinate frame (CF) into a world or object CF, we need a parameterized model of these transformations. We present a method, which allows for very different MMs to set up a model, to construct a calibration object and to estimate the model parameter from measurements on the calibration object.

C. Hirunyapruk, P. Rattanangkul, B. Thummawut, V. Plangsangmas

Laser Vibrometers have been used in many applications such as automotive and hard disk drive industries. In metrological field, laser vibrometers are employed as reference standards for the calibration of accelerometers. To have the traceability chain to the International System of Units (SI), several National metrological institutes (NMIs) and companies have developed calibration systems for laser vibrometers. National Institute of Metrology (Thailand), NIMT, is one of those NMIs. This paper describes the set-up for the primary vibrometer calibration system used at NIMT and presents the methods used according to methods 1 and 2 shown in the international standard ISO16063-41. The calibration results are also discussed.

Sari Semenoja, Martti Heinonen
A calibration system for PTU devices

Devices measuring pressure, temperature and humidity simultaneously are known as PTU devices. There are hardly any commercial calibration systems for the PTU devices available for low temperatures (< 0 °C). To obtain more comprehensive data on the performance of PTU devices, a new calibration system is developed at MIKES. In this PTU Apparatus, pressure, temperature and humidity can be controlled simultaneously so that all combinations over the ranges are possible. The nominal ranges of the system are the following: absolute pressure 500 hPa … 1200 hPa, temperature -52 °C … +80 °C and relative humidity 10 % … 95 %. The estimated uncertainties (k = 2) of the pressure, temperature and humidity are 10 Pa, 0,1 °C to 0,3 °C and 1 %RH to 3 %RH, respectively. The construction and operation as well as the results of operational tests of the PTU Apparatus are reported in this paper.

Georgiana Moraru, Marcel Istrate
A Case Study In Water And Wastewater Systems’ Energy Efficiency

World economy is closely related to energy and to how it contributes to the modernization of the society, by raising the standard of living and the degree of civilization of the population. In this context, water supply systems are attractive for energy efficiency, occupying an important place in the hierarchy of energy consumers. The purpose of this paper is to present some important aspects of a case study that must be considered in order to respond to specific requirements of water supply systems and it also shows a few measures that can be implemented with or without investments in order to reduce costs and energy consumption.

Cristiano Benedetto De Vita
A Case Study of Agrarian Assets in the Territory of Caere (6th-5th century BC)

The present paper defines some approaches employed to study the agrarian landscape of the Etruscan city of Caere.The aim is to verify some features of rural infrastructures of this territory, which has been planned systematically since the end of the 7th- early 6th century BC. Through the use of different approaches – from the archaeomorfology to the metrology, to the aerial photo interpretation – the research seeks to verify those signs suggesting systematic and symmetrical forms of occupation of the Caeretancountryside, as an effect of an articulated plan imposed by the city at the time of its greatest expansion. The results, still under development, show the constant recurrence of distances and orientations, with variations often related to the characteristics of the territory or the needs of community exploitation.

Helena Ramos, M. Pereira, V. Viegas, O. Postolache, P. Girão

The paper reports the tests conducted on a dedicated Transducer Independent Interface (TII) to check its compliance with standard IEEE 1451.2 specifications. The interface was built using a synchronous data transfer based on the Serial Peripheral Interface (SPI) protocol integrated in a PIC microcontroller used as the Smart Transducer Interface Module (STIM) and the Centronics port of the PC, used as the Network Capable Application Processor (NCAP’s TII port). The description of each line and the connections are also presented.
The working prototype of the STIM controlled by a NCAP module was implemented to connect several transducers without communication capabilities used in a water quality monitoring network. The NCAP, also described in the paper, is emulated in a PC and it was fully developed using LabVIEW 6.1.

Page 8 of 822 Results 71 - 80 of 8218