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1 – 10 of 318
Article
Publication date: 1 February 1992

B. Morten, G. De Cicco, A. Gandolfi and C. Tonelli

A study has been carried out on the relationship between the composition, poling condition and piezoelectric properties of thick film layers. Pastes based on…

Abstract

A study has been carried out on the relationship between the composition, poling condition and piezoelectric properties of thick film layers. Pastes based on lead‐titanate‐zirconate (PZT) powders, with either PbO or a lead‐alumina‐silicate glass frit as binder, were prepared. Microstructure, electrical and mechanical properties were analysed. Processing and poling conditions modify these properties; then a wide latitude of opportunities is offered in the choice of ferroelectric/piezoelectric characteristics of the layers used as sensing elements for sensors. A pressure sensor was realised where a circular diaphragm of alumina supports two piezoelectric layers obtained by screen printing and firing a PZT/PbO‐based ferroelectric paste. The design and the performance characteristics are described.

Details

Microelectronics International, vol. 9 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 February 1986

M. Prudenziati and B. Morten

The paper gives a review of the present knowledge of the piezoresistive properties of thick‐film resistors (TFRs) and shows how they have been exploited for the…

Abstract

The paper gives a review of the present knowledge of the piezoresistive properties of thick‐film resistors (TFRs) and shows how they have been exploited for the implementation of strain‐related physical‐quantities transducers. Two types of device are described in some detail. These achievements were made possible by a proper choice of resistive and conductive pastes and their firing conditions, since only in this case useful piezoresistive properties can be achieved that make TFR strain gauges competitive with metal and semiconductive materials. After examining some correlations between gauge factors, composition and structure of TFRs, new data are presented showing how the strain sensitivities may be changed by varying the peak firing temperature, dwell time and the nature of the chemical elements which diffuse from terminations in the films.

Details

Microelectronics International, vol. 3 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 March 1988

G.B. Parravicini, G. Samoggia, B. Morten and M. Prudenziati

A weak change of resistivity caused by visible radiation both for commercial and for model thick‐film (cermet) resistors (TFRs) has been observed and studied in the…

Abstract

A weak change of resistivity caused by visible radiation both for commercial and for model thick‐film (cermet) resistors (TFRs) has been observed and studied in the temperature range 10–380 K. A possible origin of this photoelectric effect in terms of photoexcited electrons emitted from the metallic grain surface into the glassy region is discussed.

Details

Microelectronics International, vol. 5 no. 3
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 30 June 2021

Chafiaa Mendil, Madjid Kidouche, Mohamed Zinelabidine Doghmane, Samir Benammar and Kong Fah Tee

The drill string vibrations can create harmful effects on drilling performance because they generate the stick-slip phenomenon which reduces the quality of drilling and…

Abstract

Purpose

The drill string vibrations can create harmful effects on drilling performance because they generate the stick-slip phenomenon which reduces the quality of drilling and decreases the penetration rate and may affect the robustness of the designed controller. For this reason, it is necessary to carefully test the different rock-bit contact models and analyze their influences on system stability in order to mitigate the vibrations. The purpose of this paper is to investigate the effects of rock-bit interaction on high-frequency stick-slip vibration severity in rotary drilling systems.

Design/methodology/approach

The main objective of this study is an overview of the influence of the rock-bit interaction models on the bit dynamics. A total of three models have been considered, and the drilling parameters have been varied in order to study the reliability of the models. Moreover, a comparison between these models has allowed the determination of the most reliable function for stick-slip phenomenon.

Findings

The torsional model with three degrees of freedom has been considered in order to highlight the effectiveness of the comparative study. Based on the obtained results, it has been concluded that the rock-bit interaction model has big influences on the response of the rotary drilling system. Therefore, it is recommended to consider the results of this study in order to design and implement a robust control system to mitigate harmful vibrations; the practical implementation of this model can be advantageous in designing a smart rotary drilling system.

Originality/value

Many rock-bit functions have been proposed in the literature, but no study has been dedicated to compare them; this is the main contribution of this study. Moreover, a case study of harmonic torsional vibrations analysis has been carried out in well-A, which is located in an Algerian hydrocarbons field, the indices of vibrations detection are given with their preventions.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 5
Type: Research Article
ISSN: 1573-6105

Keywords

Abstract

Details

Microelectronics International, vol. 12 no. 3
Type: Research Article
ISSN: 1356-5362

Abstract

Details

Microelectronics International, vol. 12 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 March 1989

N.M. White

The development of new, inexpensive, robust and miniaturised sensors is continuously being sought and it is believed that thick‐film technology can help to achieve these…

Abstract

The development of new, inexpensive, robust and miniaturised sensors is continuously being sought and it is believed that thick‐film technology can help to achieve these goals. A strain sensor utilising the piezoresistive properties of thick‐film resistors is described here. Characterisation of the sensing element has revealed that the gauge factor is significantly higher than that of metal foil strain gauges and the temperature coefficients are generally lower than those found for semiconductor strain gauges. Results show how the gauge factor can be optimised by varying the production parameters.

Details

Microelectronics International, vol. 6 no. 3
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 September 2006

Marko Hrovat, Darko Belavič, Jaroslaw Kita, Janez Holc, Silvo Drnovšek, Jena Cilenšek, Leszek Golonka and Andrzej Dziedzic

Aims to evaluate different thick‐film materials for use in strain sensors and temperature sensors on low‐temperature co‐fired ceramic (LTCC) substrates.

1375

Abstract

Purpose

Aims to evaluate different thick‐film materials for use in strain sensors and temperature sensors on low‐temperature co‐fired ceramic (LTCC) substrates.

Design/methodology/approach

LTCC materials are sintered at the low temperatures typically used for thick‐film processing, i.e. around 850°C, The thick‐film resistor materials for use as strain and temperature sensors on LTCC tapes are studied. Thick‐film piezo‐resistors in the form of strain‐gauges are realised with 10 kΩ/sq. 2041 (Du Pont)and 3414‐B (ESL), resistor materials; thick‐film temperature‐dependent resistors were made from PTC 5093 (Du Pont), and NTC‐4993 (EMCA Remex) resistor materials.

Findings

The X‐ray spectra of the 2041 and 3414‐Bb low TCR resistors after drying at 150°C and after firing display more or less the same peaks. The electrical characteristics of 2041 resistors fired on alumina and LTCC substrates are similar indicating that the resistors are compatible with the LTCC material. After firing on LTCC substrates the sheet resistivities and TCRs of the 3414‐B resistors increased. Also, there is a significant increase in the GFs from 13 to over 25.

Originality/value

Investigates the compatibility of thick‐film materials and the characteristics of the force and temperature sensors.

Details

Microelectronics International, vol. 23 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 December 1900

In 1899 the medical practitioners of Dublin were confronted with an outbreak of a peculiar and obscure illness, characterised by symptoms which were very unusual. For want…

Abstract

In 1899 the medical practitioners of Dublin were confronted with an outbreak of a peculiar and obscure illness, characterised by symptoms which were very unusual. For want of a better explanation, the disorder, which seemed to be epidemic, was explained by the simple expedient of finding a name for it. It was labelled as “beri‐beri,” a tropical disease with very much the same clinical and pathological features as those observed at Dublin. Papers were read before certain societies, and then as the cases gradually diminished in number, the subject lost interest and was dropped.

Details

British Food Journal, vol. 2 no. 12
Type: Research Article
ISSN: 0007-070X

Article
Publication date: 1 January 1987

N. White and A. Cranny

This paper describes the stages in the construction of sensors implemented in thick film technology. The use of CAD facilities greatly reduces the time required for…

Abstract

This paper describes the stages in the construction of sensors implemented in thick film technology. The use of CAD facilities greatly reduces the time required for development, and automatic design rule checking minimises errors. Steps in the fabrication from layout to finished mask(s) are detailed and specific examples given. Strain gauges using piezoresistive properties of thick film resistor inks with various sheet resistivities (Du Pont HS80 series) printed on insulated stainless steel substrates were examined under strains ranging from 0 to ±1000 microstrain. Results show gauge factors to be dependent on the ink's sheet resistivity and range from 2 to 12. The temperature coefficients of resistance were determined over temperatures of +20°C to +140°C, revealing good tracking and reproducibility.

Details

Microelectronics International, vol. 4 no. 1
Type: Research Article
ISSN: 1356-5362

1 – 10 of 318