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Page 885 of 977 Results 8841 - 8850 of 9762

Davor Zvizdic, Lovorka Grgec Bermanec, Tomislav Stasic
REALIZATION OF NATIONAL ABSOLUTE PRESSURE STANDARD AT LPM

This paper presents absolute pressure calibration system in the range from 25 kPa up to 2 MPa which is being developed in Croatian national pressure laboratory- Laboratory for Process Measurement (LPM) at Faculty of Mechanical Engineering and Naval Architecture (FSB) in Zagreb.
Design of the system, theoretical basis, effective area determination methods and the model for estimation of absolute pressure measurement uncertainty are described.

Alaaeldin A.E. Eltawil, Douglas Olson
CHARACTERIZATION OF A PRIMARY STANDARD CONTROLLED CLEARANCE PRESSURE BALANCE USING HEYDEMANN AND WELCH MODEL

For a traceable measurement to be verified and meaningful, it is important that all the measuring apparatus have to be calibrated against standards that are traceable to National/ International Standards. Calibration is a process that determines the operational integrity of mislaying instruments by determining their measurement uncertainties. In order to ensure the calibration of a measuring instrument traceable to National Standards, a hierarchy of standards and standards laboratories are established. A primary pressure standard that can metrologically characterized in a complete and an independent way with reference only to the basic units of the S.I. system, is defined as force per unit area (pressure balance) or the height of a liquid column (liquid manometer). Pressure balances are excellent primary standards for measuring pressure with high resolution and high accuracy. Characterization of primary standard pressure balance (controlled clearance) will be presented in this work.

G. Buonanno, G. Giovinco, G. Molinar Min Beciet, P. Delajoud, R. Haines
A FEM ANALYSIS OF A NEGATIVE FREE DEFORMATION PRESSURE BALANCE OPERATING UP TO 100 MPa

The main purpose of this work is the numerical and experimental analysis of an innovative negative free deformation pressure balance. The numerical prediction of the pressure distortion coefficient, the piston fall rates, the piston-cylinder elastic distortions is achieved through the Finite Element Method (FEM). The numerical results are compared to the experimental values.

Tokihiko Kobata
MEASUREMENT OF EFFECTIVE AREA RATIO OF GAS AND HYDRAULIC PRESSURE BALANCES

This paper describes a method to compare the pressure generated by gas and hydraulic pressure balances with different medium, in order to improve harmonization between a gas pressure standard and a liquid pressure standard. The pressure range compared is 0.5 MPa to 7 MPa. In the method, a gas-liquid exchanger is used and a precise pressure transducer is employed as a comparator to determine the equilibrium state between the two pressure balances. From the measurement result obtained from the method, it was shown that the effective area ratio of gas and hydraulic pressure balances was determined as a function of pressure with the estimated uncertainty in all the pressure ranges compared.

Gilder Nader, Ronny Calixto Carbonari, Emílio Carlos Nelli Silva
EXPERIMENTAL AND NUMERICAL CHARACTERIZATION OF XY PIEZOELECTRIC NANOPOSITIONERS

XY nanopositioners consist of two piezoceramic actuating a compliant mechanism. Prototypes were manufactured in aluminum using a wire EDM process, and bonded to PZT5A. Finite element simulations were carried out using the commercial ANSYS software application. Experimental analyses were conducted using laser interferometry to measure displacement, while considering a quasi-static excitation.

Gilder Nader, Paulo Tiago Fracasso, Paulo José Saiz Jabardo, José Pucci Caly, Wagner Cesar Bruna, Flavius Portella Ribas Martins, Eduardo Ferrara, Mikiya Muramatsu, Niklauss UrsusWetter, Marcos Tadeu Pereira
A LOW COST PARTICLE IMAGE VELOCIMETRY

A low cost PIV was developed for Fluid-flow measurement and studies of flow around structural models or industrial facilities in wind tunnels. The analysis were conducted in a 100 mm x 150 mm optical window. The results show that the PIV prototype is working even though further development is necessary.

Yong-Hak Huh, Dong-Iel Kim,Chang-Doo Kee
ESPI TECHNQIUE FOR MEASURING MICRO-TENSILE PROPERTIES OF THIN FILM MATERIALS

In-plane ESPI(electronic Speckle Pattern Interferometric) technique was developed to measure the micro-mechanical properties for thin film materials. The properties were determined from the micro-tensile stress and strain curve by measuring micro-tensile strain in micro-sized specimen 0.5 µm thick and 200 µm wide. The specimen was monotonically loaded by the micro-tensile loading system developed in this study. The micro-tensile strain during tensile loading was measured using the in-plane ESPI technique. In order to continuously measure the strain during loading, the subsequent strain measurement algorithm was developed. Furthermore, sensitivity to measurement of the strain was enhanced by phase estimation algorithms: sinusoidal fitting technique and object-induced dynamic phase shifting technique. Using these algorithms, the micro-tensile stress-strain curves were generated. It is shown that the sensitivity was increased by 6 times to a maximum.

Matías Roberto Viotti, Armando Albertazzi G. Jr., Ricardo Suterio
A MICHELSON INTERFEROMETER AS A CALIBRATION TOOL OF A RADIAL IN-PLANE DIGITAL SPECKLE INTERFEROMETER

The paper reports on the use of a Michelson interferometer for calibration of a radial in-plane digital speckle pattern interferometer. Also presents a numerical method to calculate a correction factor from the assessment of the displacements measured with both interferometers. This factor allows correcting mistakes introduced in the measurement process and generated mainly by a laser diode, which is used as light source of the digital speckle pattern interferometer. The description of the experimental set up and calibration procedure are presented. Experimental results obtained during one calibration process are also given. Finally, it will be demonstrated that the calibrated RIP system can measure displacements with a smaller average deviation, once the experimental results were analyzed and the calibration process was carried out, since it diminished from 6.2 % up to 1.5 %.

Leonardo Massunari Lieu, Agenor de Toledo Fleury
PROJECT OF A MICROPOSITIONING SYSTEM FOR A ROUNDNESS MEASURING MACHINE

This work presents the design of a X-Y table, which features a “Deadbeat” type controller to be used as an auxiliary device in a roundness measuring machine.
In order to give evidences and to complete the development of this work, several numerical simulations have been executed through the timing of the work and a prototype has been built to test the concepts.

Rodrigo Riquelme, Ignacio Lira, Carlos Pérez-López, Juan A. Rayas, Ramón Rodríguez-Vera
INTERFEROMETRIC MEASUREMENT OF A DIFFUSION COEFFICIENT

In this paper we present two methods to measure the diffusion coefficient in transparent media using electronic speckle pattern interferometry (ESPI). Although these methods are not new, it appears that they have not been compared, and that the proposed scheme of data treatment by least-squares adjustment for one of these methods has not been applied before. The methods were tested on a cell containing a 1.75 M NaCl solution diffusing into distilled water. Results using either method were very similar and they compare well with the value of the diffusion coefficient reported in the literature for the two substances.

Page 885 of 977 Results 8841 - 8850 of 9762