IMEKO Event Proceedings

Page 792 of 855 Results 7911 - 7920 of 8545

Dariusz Kościelnik, Marek Miśkowicz
TIME-TO-DIGITAL CONVERTER WITH DIRECT SUCCESSIVE CHARGE REDISTRIBUTION

In the paper, the enhanced version of time-to-digital converter with self-timed successive charge redistribution is presented. In the proposed solution, time-to-charge mapping realized by constant rate charge accumulation is run concurrently to the charge redistribution in the binary-weighted capacitor array. By introducing concurrent charge accumulation and redistribution, the conversion is characterized by reduced conversion time and conversion time jitter, reduction of die area of the chip, and of the number of state transitions per a single conversion cycle.

Ioannis Anagnostopoulos, Ilias Maglogiannis, Christos Anagnostopoulos, Konstantinos Makris, Eleftherios Kayafas, Vassili Loumos
Time-to-Recur Measurements in Breast Cancer Microscopic Disease Instances

In this paper we present an overview of survival curves measurements using the Kaplan-Meier approximation method. The survival curves were constructed upon the decision of an artificial neural network, which estimates the time-to-recur (TTR) in patients who presented malignant breast tumours with no evidence of distant metastases at the time of diagnosis. For our work we used the Wisconsin Prognostic Breast Cancer (WPBC) data set. The measurements taken over actual data evaluated that the accuracy of our proposed decision system is in high levels and can be used for the breast cancer prognosis problem.

Roman Kaszynski, Jacek Piskorowski
TIME-VARYING BUTTERWORTH FILTERS WITH COMPENSATED GROUP DELAY

This paper presents the concept of time-varying Butterworth filters with linear phase response. The compensation of the phase characteristics is carried out with the aid of the phase shifter system. The paper shows that it is possible to shorten the transient state in low-pass phasecompensated analog filters by varying in time selected parameters. This paper contains simulation results of the proposed filters and comparison with the classic circuits.

G. Schimetta, F. Dollinger, R. Weigel
TIRE PRESSURE MEASUREMENT USING A SAW HYBRID SENSOR

A tire pressure measuring system based on surface acoustic wave (SAW) sensors is presented. Since SAW sensors are powered by the energy of the RF field no battery is required, which is a major drawback of conventional systems. A successful combination of a SAW reflective delay line with a capacitive pressure sensor is shown. With a new way of matching the sensor impedance to the SAW reflector impedance both a high signal-to-noise ratio and a high signal dynamic are achieved which supports accurate signal evaluation. A prototype of a tire pressure sensor unit is presented.

Z. Zimniak, M. Marciniak, M. Zalewski, R. Bedzinski
TITANIUM AND ITS ALLOYS AS A MATERIAL FOR MICROPROTHESIS USED IN BIOMEDICAL ENGINEERING

Titanium is one of the most desirable material due to its durability, low density, toughness, corrosion resistance, highly creepresistant and biological compatibility. All of these mechanical and physical qualities make titanium useful in almost every area of life, especially in biomedical engineering. In ossiculoplasty they play important role, because it is possible to create very small prosthesis, which is light, strong and has satisfactory acoustic properties. This paper presents results of uniaxial compression experiments on cylindrical samples.

J.T. Filho, L.R. Lidízio, L.A. Sena, J.C. Damasceno, C.A. Achete
TITANIUM OXIDE FILMS PRODUCED BY MICRO-ARC OXIDATION FOR HIGH PERFORMANCE TITANIUM IMPLANTS

The growth of titanium oxide layer on titanium surface by the micro-arc oxidation technique was investigated. Ca(CH3COO)2 (0.3M), Na2CO3 (0.6M) and Na2HPO4 (0.1M) solutions were employed as electrolytes. SEM and EDS microanalysis were used for morphology, composition characterization and low-angle X-ray diffraction to describe titanium oxide crystallographic orientation. TiO2 films formed by using 0.3M Ca(CH3COO)2 and 0.1M Na2HPO4 solutions showed a porous, homogeneous surface structure, with presence of phosphorous and after an hydrothermical treatment using a Ca(OH)2 suspension during 24h at 60ºC was observed phosphorous and calcium.

V. Setnicka, J. Bajcsy, M. Kollar
TO PROBLEM OF MAGNETIC NON-DESTRUCTIVE TESTING

Many high quality Hall-type magnetic field sensors of advanced technology are customary available. We have experienced the use of Hall type sensors in non-destructive testing of material volume reduction due to corrosion and abrasion of iron tubes of different diameters as used for the heat exchangers, and gas pipelines.
Some results achieved by using a prototype assembly are presented. This consisted of a mechanical sensor moving support and a PC based measurement set for data recording and processing. Data gained are interpreted from the diagnosis point of view as the loss of ferromagnetic material and/or the thickness reduction. A program enabling to calculate distorted magnetic field has been developed with the aim to improve the design of sensor and to provide the measuring system with a sort of built-in intelligence for the evaluation of tests results.

Martin Novotny, Milos Sedlacek
To the uncertainty of DFT-based DSP algorithms used for processing multifrequency signals

The paper analyses effect of windowing a multi-frequency signal on the result of calculating signal parameters based on DFT. Influence of window side-lobes of nearby harmonic signals on the result of computation depends on the on the used window and on the difference in the two components magnitudes and frequencies. There are several other sources of resulting bias and uncertainty of measurements based on such algorithms. These influences are also briefly mentioned. The presented examples concern two methods of estimating RMS value, but the described principle is applicable to all algorithms based on DFT. Both theoretical relations and simulation results are included.

Elisabetta Di Francia, Ruth Lahoz, Delphine Neff, Emma Angelini, Sabrina Grassini
ToF-SIMS and u-Raman measurements on laser cleaned bronze archaeological artefacts

In this study, ToF-SIMS and u-Raman analyses have been employed to assess the feasibility of laser treatments as a selective, non invasive cleaning methodology for archaeological metallic artefacts. A Q-switched Yb:YAG fibre laser, operating at 1064 nm, has been used for the cleaning treatments, carried out in air and 18O rich atmosphere on an ancient bronze coin. The preliminary results show that laser cleaning treatment selectively removes the dangerous oxyhydroxy chlorides corrosion products without affecting the cuprite protective patina grown directly in contact with the metallic surface.

P. V. Mohanram
Tolerance design and its applications – Case studies

In today’s competitive marketplace, companies are under increased pressure to produce products that have low cost and high quality. Product cost and quality are influenced by many factors. One factor that strongly influences both is manufacturing variation. No manufacturing process can produce a part with perfect geometry. In modern manufacturing, tolerance design principles are adopted to manage the manufacturing variation and its effect on product performance and manufacturing cost. This paper presents an overview of tolerance design principles adopted in the design of mechanical assemblies. Some typical case studies on tolerance design are presented to illustrate the tolerance design concepts applicable to practical problems.

Page 792 of 855 Results 7911 - 7920 of 8545