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Article
Publication date: 1 August 2001

P.G. Babayevsky, N.A. Kozlov, A.N. Shubin, I.V. Tchurilo and T.N. Smirnova

More than 20 years’ experience in development and application of techniques and instrumentation for evaluation of space environment effect on polymer materials and…

Abstract

More than 20 years’ experience in development and application of techniques and instrumentation for evaluation of space environment effect on polymer materials and adhesively bonded joints in active experiments on‐ and overboard low Earth orbit space stations Salyute, Mir and the international space station (ISS) is reviewed. Six techniques and instrumentation sets were developed and tested for remote control of polymer materials and adhesive joints structure/properties changes during long‐term exposure in space environment. This made it possible to evaluate visco‐elastic and dielectric properties, surface defectiveness and crack resistance as material parameters, which are sensitive to structure changes of polymer materials and adhesive joints and are their important service characteristics. Some experimental results of the techniques and instrumentation, ground and space tests are presented.

Details

Aircraft Engineering and Aerospace Technology, vol. 73 no. 4
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 17 July 2009

Julie Labatut, Franck Aggeri, Jean‐Michel Astruc, Bernard Bibé and Nathalie Girard

The purpose of this paper is to investigate the role of instruments defined as artefacts, rules, models or norms, in the articulation between knowing‐in‐practice and…

Abstract

Purpose

The purpose of this paper is to investigate the role of instruments defined as artefacts, rules, models or norms, in the articulation between knowing‐in‐practice and knowledge, in learning processes.

Design/methodology/approach

The paper focuses on a distributed, knowledge‐intensive and instrumented activity at the core of any collective action: qualification. The particular case of breeding activities in the livestock sector has been studied, where collective practices of animal qualification for collective breeding have been studied. Qualitative data stemming from in‐depth interviews and observation of daily practices have been analysed, combining practice‐based approaches on knowing processes and science philosophers' theories on the use of instruments during action.

Findings

The study of instruments used in daily practices allows us to go beyond the dichotomy between opposite types of knowledge, i.e. scientific knowledge seen as a stock, and sensible knowledge seen as purely tacit and equated to non‐instrumented practices. Instruments are not merely mediators in learning processes; they also take an active part in shaping and activating knowledge and learning processes.

Research limitations/implications

Further research is needed on the designing of reflexive instrumentation, which takes knowing and knowledge articulation into account better.

Practical implications

Using instruments as a key concept to analyse knowing‐in‐practice processes has both methodological and managerial implications for identifying those instruments that favour learning processes.

Originality/value

This paper complements more classical practice‐based approaches by proposing a new perspective on instruments in learning processes, which is particularly relevant to the study of pluralistic organisations where power is diffuse.

Details

The Learning Organization, vol. 16 no. 5
Type: Research Article
ISSN: 0969-6474

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Article
Publication date: 11 June 2020

José Francisco Villarreal Valderrama, Luis Takano, Eduardo Liceaga-Castro, Diana Hernandez-Alcantara, Patricia Del Carmen Zambrano-Robledo and Luis Amezquita-Brooks

Aircraft pitch control is fundamental for the performance of micro aerial vehicles (MAVs). The purpose of this paper is to establish a simple experimental procedure to…

Abstract

Purpose

Aircraft pitch control is fundamental for the performance of micro aerial vehicles (MAVs). The purpose of this paper is to establish a simple experimental procedure to calibrate pitch instrumentation and classical control algorithms. This includes developing an efficient pitch angle observer with optimal estimation and evaluating controllers under uncertainty and external disturbances.

Design/methodology/approach

A wind tunnel test bench is designed to simulate fixed-wing aircraft dynamics. Key elements of the instrumentation commonly found in MAVs are characterized in a gyroscopic test bench. A data fusion algorithm is calibrated to match the gyroscopic test bench measurements and is then integrated into the autopilot platform. The elevator-angle to pitch-angle dynamic model is obtained experimentally. Two different control algorithms, based on model-free and model-based approaches, are designed. These controllers are analyzed in terms of parametric uncertainties due to wind speed variations and external perturbation because of sudden weight distribution changes. A series of experimental tests is performed in wind-tunnel facilities to highlight the main features of each control approach.

Findings

With regard to the instrumentation algorithms, a simple experimental methodology for the design of optimal pitch angle observer is presented and validated experimentally. In the context of the platform design and identification, the similitude among the theoretical and experimental responses shows that the platform is suitable for typical pitch control assessment. The wind tunnel experiments show that a fixed linear controller, designed using classical frequency domain concepts, is able to provide adequate responses in scenarios that approximate the operation of MAVs.

Research limitations/implications

The aircraft orientation observer can be used for both pitch and roll angles. However, for simultaneousyaw angle estimation the proposed design method requires further research. The model analysis considers a wind speed range of 6-18 m/s, with a nominal operation of 12 m/s. The maximum experimentally tested reference for the pitch angle controller was 20°. Further operating conditions may require more complex control approaches (e.g. scheduling, non-linear, etc.). However, this operating range is enough for typical MAV missions.

Originality/value

The study shows the design of an effective pitch angle observer, based on a simple experimental approach, which achieved locally optimum estimates at the test conditions. Additionally, the instrumentation and design of a test bench for typical pitch control assessment in wind tunnel facilities is presented. Finally, the study presents the development of a simple controller that provides adequate responses in scenarios that approximate the operation of MAVs, including perturbations that resemble package delivery and parametric uncertainty due to wind speed variations.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 7
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 2 January 2018

P. Pandiyan, G. Uma and M. Umapathy

This paper aims to present a design and simulation of electrostatic nanoelectromechanical system (NEMS)-based logic gates using laterally actuated cantilever with…

Abstract

Purpose

This paper aims to present a design and simulation of electrostatic nanoelectromechanical system (NEMS)-based logic gates using laterally actuated cantilever with double-electrode structure that can implement logic functions, similar to logic devices that are made of solid-state transistors which operates at 5 V.

Design/methodology/approach

The analytical modeling of NEMS switch is carried out for finding the pull-in and pull-out voltage based on Euler-Bernoulli’s beam theory, and its numerical simulation is performed using finite element method computer-aided design tool COVENTORWARE.

Findings

This paper reports analytical and numerical simulation of basic NEMS switch to realize the logic gates. The proposed logic gate operates on 5 V which suits well with conventional complementary metal oxide semiconductor (CMOS) logic which in turn reduces the power consumption of the device.

Originality/value

The proposed logic gates use a single bit NEMS switch per logic instead of using 6-14 individual transistors as in CMOS. One exclusive feature of this proposed logic gates is that the basic NEMS switch is structurally modified to function as specific logic gates depending upon the given inputs.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 June 2019

Manjunath Manuvinakurake, Uma Gandhi, Mangalanathan Umapathy and Manjunatha M. Nayak

Structures play a very important role in developing pressure sensors with good sensitivity and linearity, as they undergo deformation to the input pressure and function as…

Abstract

Purpose

Structures play a very important role in developing pressure sensors with good sensitivity and linearity, as they undergo deformation to the input pressure and function as the primary sensing element of the sensor. To achieve high sensitivity, thinner diaphragms are required; however, excessively thin diaphragms may induce large deflection and instability, leading to the unfavorable performances of a sensor in terms of linearity and repeatability. Thereby, importance is given to the development of innovative structures that offer good linearity and sensitivity. This paper aims to investigate the sensitivity of a bossed diaphragm coupled fixed guided beam three-dimensional (3D) structure for pressure sensor applications.

Design/methodology/approach

The proposed sensor comprises of mainly two sensing elements: the first being the 3D mechanical structure made of bulk silicon consisting of boss square diaphragm along with a fixed guided beam landing on to its center, forming the primary sensing element, and the diffused piezoresistors, which form the secondary sensing element, are embedded in the tensile and compression regions of the fixed guided beam. This micro mechanical 3 D structure is packaged for applying input pressure to the bottom of boss diaphragm. The sensor without pressure load has no deflection of the diaphragm; hence, no strain is observed on the fixed guided beam and also there is no change in the output voltage. When an input pressure P is applied through the pressure port, there is a deformation in the diaphragm causing a deflection, which displaces the mass and the fixed guided beam vertically, causing strain on the fixed guided beam, with tensile strain toward the guided end and compressive strain toward the fixed end of the close magnitudes. The geometrical dimensions of the structure, such as the diaphragm, boss and fixed guided beam, are optimized for linearity and maximum strain for an applied input pressure range of 0 to 10 bar. The structure is also analyzed analytically, numerically and experimentally, and the results are compared.

Findings

The structure offers equal magnitudes of tensile and compressive stresses on the surface of the fixed guided beam. It also offers good linearity and sensitivity. The analytical, simulation and experimental studies of this sensor are introduced and the results correlate with each other. Customized process steps are followed wherein two silicon-on-insulator (SOI) wafers are fusion bonded together, with SOI-1 wafer used to realize the diaphragm along with the boss and SOI-2 wafer to realize the fixed guided beam, leading to formation of a 3D structure. The geometrical dimensions of the structure, such as the diaphragm, boss and fixed guided beam, are optimized for linearity and maximum strain for an applied input pressure range of 0 to10 bar.

Originality/value

This paper presents a unique and compact 3D micro-mechanical structure pressure sensor with a rigid center square diaphragm (boss diaphragm) and a fixed guided beam landing at its center, with diffused piezoresistors embedded in the tensile and compression regions of the fixed guided beam. A total of six masks were involved to realize and fabricate the 3D structure and the sensor, which is presumed to be the first of its kind in the fabrication of MEMS-based piezoresistive pressure sensor.

Details

Sensor Review, vol. 39 no. 4
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 May 1970

L.F.E. Coombs

FORWARD looking technical activities within the Aviation Division of Smiths Industries Ltd. will represent a major part of their research expenditure over the next few…

Abstract

FORWARD looking technical activities within the Aviation Division of Smiths Industries Ltd. will represent a major part of their research expenditure over the next few years. Current and forward projects include: the application of digital techniques to flight and engine control systems; electronic head up and head down displays and instrumentation; the development of radiation pyrometry for gas turbines; investigation into new methods of fuel measurement including nuclear radiation; the development of new types of instrumentation such as numeric indicators, electronic clocks and fuel management clocks.

Details

Aircraft Engineering and Aerospace Technology, vol. 42 no. 5
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 August 1963

W.A. Pullman

During a recent meeting on Teaching Design at the Institution of Mechanical Engineers, there was considerable discussion as to whether the universities trained embryo…

Abstract

During a recent meeting on Teaching Design at the Institution of Mechanical Engineers, there was considerable discussion as to whether the universities trained embryo engineers or ‘thinking‐machines’. For students following a sandwich course leading to a Dip. Tech. or degree there is no point in this distinction. For half the course, the student is in industry doing real engineering and he regards himself as a potential engineer. A college must recognise this and plan its courses accordingly. Thus, whereas a university student may well graduate without any knowledge of instrumentation as used in modern industry, his counterpart on a sandwich course is well aware of what is used. If he is to take his college studies seriously and regard laboratory work as a challenge and not a chore, then the associated instrumentation must be as modern as he uses outside the college.

Details

Education + Training, vol. 5 no. 8
Type: Research Article
ISSN: 0040-0912

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Article
Publication date: 1 January 1990

P. Ryalls and A. Stevens

Outlines the methods used to construct two basements at the newBritish Library, and the precautions taken to monitor and prevent groundmovement and related damage to…

Abstract

Outlines the methods used to construct two basements at the new British Library, and the precautions taken to monitor and prevent ground movement and related damage to adjacent buildings and London Underground tunnels. Discusses the proposed construction sequence, the prediction of ground movements and the comprehensive survey and ground instrumentation programme installed. Explains the type, purpose and criteria for the instrumentation required and details their positioning in order to monitor possible damage, with particular reference to London Underground and St Pancras Station. Details the results of the survey over the nine‐year construction period, in comparison with predictions, and the plans for continuation of surveys until work is complete.

Details

Structural Survey, vol. 8 no. 1
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 16 March 2015

Yingping Hong, Ting Liang, Pinggang Jia, Wenyi Liu, Qiulin Tan, Chen Li, Tingli Zheng, Binger Ge and Jijun Xiong

Physical contact and traditional sensitive structure Physical contact and traditional pressure-sensitive structures typically do not operate well in harsh environments…

Abstract

Purpose

Physical contact and traditional sensitive structure Physical contact and traditional pressure-sensitive structures typically do not operate well in harsh environments. This paper proposes a high-temperature pressure measurement system for wireless passive pressure sensors on the basis of inductively coupled LC resonant circuits.

Design/methodology/approach

This paper begins with a general introduction to the high-temperature pressure measurement system, which consists of a reader antenna inductively coupled to the sensor circuit, a readout unit and a heat insulation unit. The design and fabrication of the proposed measurement system are then described in detail.

Findings

A wireless passive pressure sensor without an air channel is fabricated using high-temperature co-fired ceramics (HTCC) technology and its signal is measured by the designed measurement system. The designed heat insulation unit keeps the reader antenna in a safe environment of 159.5°C when the passive sensor is located in a 900°C high-temperature zone continuously for 0.5 h. The proposed system can effectively detect the sensor’s resonance frequency variation in a high bandwidth from 1 to 100 MHz with a frequency resolution of 0.006 MHz, tested from room temperature to 500°C for 30 min.

Originality/value

Expensive and bulky equipment (impedance analyzers or network analyzers) restrict the use of the readout method outside the laboratory environment. This paper shows that a novel readout circuit can replace the laboratory equipment to demodulate the measured pressure by extracting the various sensors’ resonant frequency. The proposed measurement system realizes automatic and continuous pressure monitoring in a high-temperature environment with a coupled distance of 2.5 cm. The research finding is meaningful for the measurement of passive pressure sensors under a wide temperature range.

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Article
Publication date: 1 March 2005

J.E. Hardy and T.E. McKnight

Bench‐top wind tunnels are used extensively by the US Air Force for calibrating anemometers. As anemometers have improved, the need for reduced uncertainties in the…

Abstract

Purpose

Bench‐top wind tunnels are used extensively by the US Air Force for calibrating anemometers. As anemometers have improved, the need for reduced uncertainties in the bench‐top wind tunnels was required. A three‐pronged approach was used to reduce low velocity uncertainties by a factor of 2‐3.Design/methodology/approach – The reduction in velocity uncertainties was achieved by upgrading the wind tunnel instrumentation that measured the pressure and differential pressure and by improving the velocity calibration of the bench‐top wind tunnel. A detailed uncertainty analysis was performed to determine how much the instrumentation needed to improve. A laser Doppler velocimetry (LDV) was used to calibrate each wind tunnel at low velocities.Findings – The uncertainty analysis indicated that the main contributors to the velocity uncertainty were the differential pressure and the pressure measurements. These two process instruments were upgraded to reduce their individual uncertainties by a factor of 2. Additionally each bench‐top wind tunnel was calibrated using the LDV with special emphasis on flows from 0.15‐3.0 m/s. In all, nine wind tunnels were calibrated and the upgraded systems exhibited a reduction in uncertainties in the low flow region of a factor of 2‐3.Originality/value – A need to reduce velocity uncertainties in bench‐top wind tunnels was a requirement for the US Air Force calibration program. Upgraded instrumentation and individual calibration with an LDV provided the needed reduction. In the low flow region of 0.15 to 3.0 m/s, uncertainties were reduced by a factor of 2‐3.

Details

Sensor Review, vol. 25 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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