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Article
Publication date: 1 July 2003

Gianmarco Radice

The purpose of this paper is to present a new approach in the concept and implementation of autonomous micro‐spacecraft. The one true “artificial agent” approach to…

Abstract

The purpose of this paper is to present a new approach in the concept and implementation of autonomous micro‐spacecraft. The one true “artificial agent” approach to autonomy requires the micro‐spacecraft to interact in a direct manner with the environment through the use of sensors and actuators. As such, little computational effort is required to implement such an approach, which is clearly of great benefit for limited micro‐satellites. Rather than using complex world models, which have to be updated, the agent is allowed to exploit the dynamics of its environment for cues as to appropriate actions to achieve mission goals. The particular artificial agent implementation used here has been borrowed from studies of biological systems, where it has been used successfully to provide models of motivation and opportunistic behaviour. The so‐called “cue‐deficit” action selection algorithm considers the micro‐spacecraft to be a non‐linear dynamical system with a number of observable states. Using optimal control theory rules are derived which determine which of a finite repertoire of behaviours the satellite should select and perform. The principal benefits of this approach is that the micro‐spacecraft is endowed with self‐sufficiency, defined here to be the ability to achieve mission goals, while never placing itself in an irrecoverable position.

Details

Kybernetes, vol. 32 no. 5/6
Type: Research Article
ISSN: 0368-492X

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Leading Education Systems
Type: Book
ISBN: 978-1-80071-130-3

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Book part
Publication date: 14 May 2018

Kathleen Rehbein, Frank den Hond and Frank G. A. Bakker

Corporate social responsibility (CSR) and corporate political activity (CPA) are two important components of firms’ nonmarket strategies, oriented toward shaping the…

Abstract

Corporate social responsibility (CSR) and corporate political activity (CPA) are two important components of firms’ nonmarket strategies, oriented toward shaping the firm’s political and social conditions. Although this is acknowledged in the literature, there are contradictory arguments and evidence, concerning, first, whether and under which conditions firms align their CPA and CSR activities, and second, what the impacts might be if they do align these activities. In light of this, this chapter draws from earlier reviews of nonmarket strategies, to explore the factors at multiple levels, macro and micro, that may drive a firm’s alignment of CPA and CSR. In doing so, we draw from management research to identify the macro- and micro-level factors that shape CPA and CSR alignment as CSR and CPA alignment research mostly focuses on outcomes rather than identifying the drivers of alignment. We develop a general model that integrates the macro- and micro-level discussions to make suggestions about where future research needs to go to increase understanding of when corporations will combine their CPA and CSR efforts and the merits of these efforts.

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Book part
Publication date: 6 May 2008

Patricia A. McAnany

The most powerful and effective forces of hierarchizing are those that naturalize difference so that it is beyond dispute and something to be tacitly accepted. In the…

Abstract

The most powerful and effective forces of hierarchizing are those that naturalize difference so that it is beyond dispute and something to be tacitly accepted. In the Classic Maya world, this “social speciation” was materialized and naturalized through a complex web of ritual practice, deity emulation, enhancement of body aesthetics, and the fabrication and possession of hypertrophic goods. The architecture of Classic Maya royal courts broke with an older Maya residential pattern of accretional construction filled with ancestral burials in order to materialize more effectively social difference, to provide space for exclusive ritual performance, and to showcase the highly valued and gendered labor of textile production. Such instruments of authority are “weapons of exclusion” that can be wielded to fend off assaults on hierarchy. From this perspective, informed by the ritual economy approach, the profound transformations of the 9th century in the Maya lowlands are considered an assault that was not defendable.

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Dimensions of Ritual Economy
Type: Book
ISBN: 978-1-84950-546-8

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Article
Publication date: 3 April 2017

Ren-huai Liu, Kai Sun and Dongchuan Sun

The purpose of this article is to put forward China’s Hanyu Pinyin word guanli as an academic basic term to the world.

Abstract

Purpose

The purpose of this article is to put forward China’s Hanyu Pinyin word guanli as an academic basic term to the world.

Design/methodology/approach

GUANLI as an academic basic term, which holds multiple meanings of several English words, such as management, administration, governance, etc. As a basic term, GUANLI, derived several words, such as GUANLIOLOGY, GUANLIST/GUANLIER and GUANLIWORK/GUANLIJOB, to precisely and exactly convey the Chinese GUANLI ideas. It is the historical mission and opportunity for the authors to research and establish the Chinese School of Modern GUANLI Science (CSMGS).

Findings

It is inevitably necessary to build the combined Chinese–Western discourse system of GUANLI science (CCWDSGS). Some other research results of CSMGS are also presented in this paper.

Research limitations/implications

It is needless to say that there are still lots of problems in China, including in the GUANLI field. These problems will gradually be solved in China’s reform and development that takes place continuously. New problems will come up while old problems are being solved and settled; problems producing in a loop, problems solving in a loop, this is the dialectics. The authors have full confidence in solving problems, as well as in China’s development and future.

Originality/value

Practice comes first and then it is followed by theory. The authors first have the “China Model”, followed by the “Chinese School” consequently. The “China Model” has already been there, and the “Chinese School” relies on the author’s proactive research and innovation. It is just the right time for the authors to study and create the CSMGS. This is the historical mission and opportunity awaited by contemporary Chinese.

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Article
Publication date: 12 February 2018

Ranga Babu J.A., Kiran Kumar K. and Srinivasa Rao S.

This paper aims to present an analytical investigation of energy and exergy performance on a solar flat plate collector (SFPC) with Cu-CuO/water hybrid nanofluid, Cu/water…

Abstract

Purpose

This paper aims to present an analytical investigation of energy and exergy performance on a solar flat plate collector (SFPC) with Cu-CuO/water hybrid nanofluid, Cu/water and CuO/water nanofluids as collector running fluids.

Design/methodology/approach

Heat transfer characteristics, pressure drop and energy and exergy efficiencies of SFPC working on these nanofluids are investigated and compared. In this study, a comparison is made by varying the mass flow rates and nanoparticle volume concentration. Thermophysical properties of hybrid nanofluids are estimated using distinctive correlations available in the open literature. Then, the influence of these properties on energy and exergy efficiencies of SFPC is discussed in detail.

Findings

Energy analysis reveals that by introducing the hybrid nanoparticles in water, the thermal conductivity of the working fluid is enhanced by 17.52 per cent and that of the individual constituents is enhanced by 15.72 and 15.35 per cent for Cu/water and CuO/water nanofluids, respectively. This resulted in 2.16 per cent improvement in useful heat gain for hybrid nanofluid and 1.03 and 0.91 per cent improvement in heat gain for Cu/water and CuO/water nanofluids, respectively. In line with the above, the collector efficiency increased by 2.175 per cent for the hybrid nanofluid and 0.93 and 1.05 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Exergy analysis elucidates that by using the hybrid nanofluid, exergy efficiency is increased by 2.59 per cent, whereas it is 2.32 and 2.18 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Entropy generation is reduced by 3.31, 2.35 and 2.96 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, as compared to water.

Research limitations/implications

However, this is associated with a penalty of increment in pressure drop of 2.92, 3.09 and 2.74 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, compared with water.

Originality/value

It is clear from the analysis that Cu-CuO/water hybrid nanofluids possess notable increment in both energy and exergy efficiencies to use them in SFPCs.

Details

World Journal of Engineering, vol. 15 no. 1
Type: Research Article
ISSN: 1708-5284

Keywords

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Book part
Publication date: 27 May 2021

Nolwenn Bühler

Abstract

Details

When Reproduction Meets Ageing
Type: Book
ISBN: 978-1-83909-747-8

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Article
Publication date: 1 August 2000

V.H. Mucino, J.E. Smith and K. Sun

In this paper a new method for the hydrodynamic analysis of a sliding cylinder in a lubricated parallel track is presented. The method is an extension of Booker’s…

Abstract

In this paper a new method for the hydrodynamic analysis of a sliding cylinder in a lubricated parallel track is presented. The method is an extension of Booker’s “Mobility Method” (developed for cylindrical journal bearings) for the case of a non‐rotating sliding cylinder in a parallel track. In this application, the clearance between the track and the cylinder, the viscosity of the lubricant, the radius and length of the pin, the sliding velocity and the applied transverse load determine the hydrodynamic behavior of the slider cylinder. An axial positive displacement vane device is used to illustrate the applicability of the hydrodynamic mobility approach for a lubrication analysis. A rotor and a stationary cylindrical cam with cycloidal tracks drive the axicycloidal motion of vanes. A case analysis is presented for a device running at constant speed, in which the inertia forces, friction forces and direct vane loads are taken into account to determine the hydrodynamic behavior of the sliding pins. The following results are produced: pin eccentricity paths, minimum lubricant film thickness history, peak film pressure history and pressure distributions on the cylindrical at any point of the motion. Results show small departures from the purely cycloidal lift‐dwell‐return‐dwell motion of the vanes due to the hydrodynamic performance of the pins.

Details

Industrial Lubrication and Tribology, vol. 52 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 18 March 2019

Mohamed Ali Zdiri, Badii Bouzidi and Hsan Hadj Abdallah

This paper aims to analyze and investigate the performance of an improved fault detection and identification (FDI) method based on multiple criteria, applied to six-switch…

Abstract

Purpose

This paper aims to analyze and investigate the performance of an improved fault detection and identification (FDI) method based on multiple criteria, applied to six-switch three-phase inverter (SSTPI)-fed induction motor (IM) drives under both single and multiple open insulated-gate bipolar transistors(IGBT) faults.

Design/methodology/approach

This paper proposes an advanced diagnostic method for both single and multiple open IGBT faults dedicated to SSTPI-fed IM drives considering five distinct faulty operating conditions as follows: a single IGBT open-circuit fault, a single-phase open-circuit fault, a non-crossed double fault in two different legs, a crossed double fault in two different legs and a three-IGBT open-circuit fault. This is achieved because of the introduction of a new diagnosis variable provided using the information of the slope of the current vector in (α-β) frame. The proposed FDI method is based on the synthesis and the analysis, under both healthy and faulty operations, of the behaviors of the introduced diagnosis variable, the three motor phase currents and their normalized average values. Doing so, the developed FDI method allows a best compromise of fast detection and precision localization of IGBT open-circuit fault of the inverter.

Findings

Simulation works, carried out considering the implementation of the direct rotor flux oriented control in an IM fed by the conventional SSTPI, have proved the high performance of the advanced FDI method in terms of fast fault detection associated with a high robustness against false alarms, against speed and load torque fast variations and against the oscillations of the DC-bus voltage in the case of both healthy and faulty operations.

Research limitations/implications

This work should be extended considering the validation of the obtained simulation results through experiments.

Originality/value

Different from other FDI methods, which suffer from a low diagnostic effectiveness for low load levels and false alarms during transient operation, this method offers the potentialities to overcome these drawbacks because of the introduction of the new diagnosis variable. This latter, combined with the information provided from the three motor phase currents and their normalized average values allow a more efficient detection and identification of IGBT open-circuit fault.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 March 2005

M. McSherry, C. Fitzpatrick and E. Lewis

There are various temperature measuring systems presented in the literature and on the market today. Over the past number of years a range of luminescent‐based optical…

Abstract

Purpose

There are various temperature measuring systems presented in the literature and on the market today. Over the past number of years a range of luminescent‐based optical fibre sensors have been reported and developed which include fluorescence and optical scattering. These temperature sensors incorporate materials that emit wavelength shifted light when excited by an optical source. The majority of commercially available systems are based on fluorescent properties.Design/methodology/approach – Many published journal articles and conference papers were investigated and existing temperature sensors in the market were examined.Findings – In optical thermometry, the light is used to carry temperature information. In many cases optical fibres are used to transmit and receive this light. Optical fibres are immune to electromagnetic interference and are small in size, which allows them to make very localized measurements. A temperature sensitive material forms a sensor and the subsequent optical data are transmitted via optical fibres to electronic detection systems. Two keys areas were investigated namely fluorescence based temperature sensors and temperature sensors involving optical scattering.Originality/value – An overview of optical fibre temperature sensors based on luminescence is presented. This review provides a summary of optical temperature sensors, old and new which exist in today's world of sensing.

Details

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

Keywords

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