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Article

Shijia Wang

This paper aims to improve shearer positioning accuracy. Shearer positioning using an inertial navigation system (INS) is a highly useful technology; however, positioning…

Abstract

Purpose

This paper aims to improve shearer positioning accuracy. Shearer positioning using an inertial navigation system (INS) is a highly useful technology; however, positioning accuracy is seriously hindered by INS attitude error, particularly heading drift.

Design/methodology/approach

A shearer positioning model with double-INS based on extended Kalman filter was proposed. The constant distance between two INSs (INS 1 and INS 2) was selected as the observation vector. Allan variance was used to identify the noise type of the vertical-axis gyroscope, and the stochastic process of heading drift for two INSs was obtained and divided into incongruous drift and concurrent drift.

Findings

Simulation was then carried out to determine the optimal arrangement of the two INSs. For incongruous drift, the optimal arrangement satisfied the condition that the line connecting INS 1 and INS 2 was perpendicular to the shearer lateral axis (in the shearer coordinate frame) and parallel to the east-north plane (in the east-north-up coordinate frame). Under optimal arrangement, the positioning accuracy increased against the distance between INS 1 and INS 2. For concurrent drift, the double-INS positioning model had no effect. Under the circumstances, the number of INSs should be increased so that the uncertainty of INS drift was reflected as much as possible.

Originality/value

A new double-INS positioning model was proposed with the constant distance between the two INSs. The optimal arrangement for double-INS was obtained.

Details

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

Keywords

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Article

Seyed Hadi Hoseinie, Mohammad Ataei, Reza Khalokakaie, Behzad Ghodrati and Uday Kumar

Longwall mining is a special mining method with high productivity and smooth operation and the drum shearer is known as the most important component in longwall mines due…

Abstract

Purpose

Longwall mining is a special mining method with high productivity and smooth operation and the drum shearer is known as the most important component in longwall mines due to its direct role in the coal cutting and production process. Therefore, its reliability is important in keeping the mine production at a desired level. Hence, reliability analysis is essential in identifying and removing existing problems of this machine in order to achieve a better production condition. This paper seeks to learn about the reliability of the shearer machine in order to locate critical subsystems. The improvement of the reliability of the critical subsystems, to enhance the optimum operation of the shearer machine, is the main objective of this research.

Design/methodology/approach

A basic methodology was used in this paper for the reliability modeling of the shearer machine. First, failure and performance data from a two‐year period at the Tabas Coal Mine‐Iran was classified and sorted. The tests for validating the assumption of independent and identical distribution (iid) of TBF data are done and the best modeling method for each subsystem was selected among the renewal process, homogeneous Poisson process and non‐homogeneous Poisson process. Finally, the reliability of subsystems and the machine were assessed.

Findings

The study revealed that six important subsystems of the shearer machine are; water system, haulage, electrical system, hydraulic system, cutting arms, and cable system. Pareto analysis shows that the 30 percent of failures and stoppages of the shearer were related to the water system and this system is the most critical subsystem of the machine. The failure rate analysis shows that the failure rates of the hydraulic, haulage and electrical systems were decreasing, meanwhile, the failure rates of the water system, cutting arms and cable system were increasing. The reliability of drum shearer reaches the zero value after 100 hours.

Originality/value

This paper, for the first time, defines a practical set of subsystems for the coal shearer based on field data and machine design.

Details

Journal of Quality in Maintenance Engineering, vol. 18 no. 1
Type: Research Article
ISSN: 1355-2511

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Article

J. Thesiger

July 28, 1971 Mines and quarries — Act of 1954 — Duty to set holing supports — Whether applicable to prop free face cut by shearer machine — Common law duty of care …

Abstract

July 28, 1971 Mines and quarries — Act of 1954 — Duty to set holing supports — Whether applicable to prop free face cut by shearer machine — Common law duty of care — Technical mining knowledge and experience — Relevant date for considering — Whether at date of accident — Mines and Quarries Act, 1954 (2 & 3 Eliz. II, c.70), s.81(l) — Coal and Other Mines (Support… Regulations), 1956 (S.I.1956 No. 1763), reg. 10(1)

Details

Managerial Law, vol. 12 no. 5
Type: Research Article
ISSN: 0309-0558

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Article

Marcelo Santiago Sousa, Pedro Paglione, Roberto Gil Annes Silva, Flavio Luiz Cardoso-Ribeiro and Sebastião Simões Cunha

The purpose of this paper is to present a mathematical model of one very flexible transport category airplane whose structural dynamics was modeled with the strain-based…

Abstract

Purpose

The purpose of this paper is to present a mathematical model of one very flexible transport category airplane whose structural dynamics was modeled with the strain-based formulation. This model can be used for the analysis of couplings between the flight dynamics and structural dynamics.

Design/methodology/approach

The model was developed with the use of Hamiltonian mechanics and strain-based formulation. Nonlinear flight dynamics, nonlinear structural dynamics and inertial couplings are considered.

Findings

The mathematical model allows the analysis of effects of high structural deformations on airplane flight dynamics.

Research limitations/implications

The mathematical model has more than 60 degrees of freedom. The computational burden is too high, if compared to the traditional rigid body flight dynamics simulations.

Practical implications

The mathematical model presented in this work allows a detailed analysis of the couplings between flight dynamics and structural dynamics in very flexible airplanes. The better comprehension of these couplings will contribute to the development of flexible airplanes.

Originality/value

This work presents the application of nonlinear flight dynamics-nonlinear structural dynamics-strain-based formulation (NFNS_s) methodology to model the flight dynamics of one very flexible transport category airplane. This paper addresses also the way as the analysis of results obtained in nonlinear simulations can be made. Comparisons of the NFNS_s and nonlinear flight dynamics-linear structural dynamics methodologies are presented in this work.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

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Article

James Shearer, Alex D. Wodak and Kate A. Dolan

The study evaluated the introduction of naltrexone in an Australian prison system for imprisoned male heroin users. Treatment outcomes were analysed for two sub‐samples…

Abstract

The study evaluated the introduction of naltrexone in an Australian prison system for imprisoned male heroin users. Treatment outcomes were analysed for two sub‐samples taken from an unsuccessful randomised controlled trial. The first sample comprised 68 participants who were randomly allocated to naltrexone treatment. The second sample comprised 47 participants who commenced opioid pharmacotherapy during the study period. Thirteen per cent of subjects started naltrexone, with only 7% retained in treatment at six months. Six‐month retention was significantly lower in naltrexone compared to methadone (p = 0.0007). Poor patient acceptability and retention did not support oral naltrexone maintenance in this treatment group.

Details

International Journal of Prisoner Health, vol. 3 no. 3
Type: Research Article
ISSN: 1744-9200

Keywords

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Article

John Francis McKernan and Katarzyna Kosmala MacLullich

This paper analyses what is seen as a crisis of authority in financial reporting. It considers the view that an element of authority may be restored to accounting through…

Abstract

This paper analyses what is seen as a crisis of authority in financial reporting. It considers the view that an element of authority may be restored to accounting through communicative reason. The paper argues that the justice‐oriented rationality of traditional, Habermasian, communicative ethics is incapable of providing a solid foundation for the re‐authorisation of financial reporting. The paper argues that a more adequate foundation might be found in an enlarged communicative ethics that allows space to the other of justice‐oriented reason. The inspiration for the enlargement is found in Ricoeur's analysis of narrative, his exploration of its role in the figuration of identity, and in his biblical hermeneutics which reveals the necessity of an active dialectic of love and justice.

Details

Accounting, Auditing & Accountability Journal, vol. 17 no. 3
Type: Research Article
ISSN: 0951-3574

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Article

Sara Ann Reiter

Investigates two issues raised by D.C. Moore: the apparent failureof critical accounting theory to launch and sustain a critical programmeand relative lack of critical…

Abstract

Investigates two issues raised by D.C. Moore: the apparent failure of critical accounting theory to launch and sustain a critical programme and relative lack of critical accounting activity in the USA. These concerns are related in that radicalization and change of one′s own academic discipline would seem to be one of the highest‐priority political activities to be undertaken by critical theorists. Offers feminist economics as an example of a critical social theory that meets Moore′s four criteria for successful criteria endeavour and is applicable to accounting research. Compares the feminist economic critique with critiques of accounting by Cooper, and by Shearer and Arrington, based on the French feminist philosophers. The two approaches differ in goals and politics. Suggests that the experience of feminist economics in reforming economics also provides insights into the slow growth of critical accounting theory in the USA.

Details

Accounting, Auditing & Accountability Journal, vol. 8 no. 3
Type: Research Article
ISSN: 0951-3574

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Book part

C. Bram Cadsby, Fei Song and Francis Tapon

We demonstrate in a laboratory experiment that the effectiveness of performance-contingent incentives is inversely related to risk-aversion levels. For about 16.5% of…

Abstract

We demonstrate in a laboratory experiment that the effectiveness of performance-contingent incentives is inversely related to risk-aversion levels. For about 16.5% of participants, performance fails to improve under performance-pay, and the probability of such failure increases with risk-aversion. This phenomenon works in part through the reduced effort level of more risk-averse individuals when effort level is positively correlated with risk exposure. It is also associated with higher self-reported levels of stress by more risk-averse people working under performance-contingent pay. We find no evidence of such stress causing decrements in the quality of effort affecting performance after controlling for effort level. However, controlling for effort, more risk-averse participants perform better under a fixed salary, leaving less room for improvement under performance-pay.

Details

Experiments in Organizational Economics
Type: Book
ISBN: 978-1-78560-964-0

Keywords

Content available
Book part

Deb Aikat

Dubbed as the “first digital generation,” the millennials (or Generation Y) have been ensconced in digital technologies throughout their lives. As a demographic cohort…

Abstract

Dubbed as the “first digital generation,” the millennials (or Generation Y) have been ensconced in digital technologies throughout their lives. As a demographic cohort, the eldest members of Generation Y were the first to reach adulthood by 2001, which heralded the third millennium, and were, therefore, called the millennials.

This research study theorizes that the millennials are ushering an emerging post-digital era that is redefining how we live, work, and play. By situating media consumption within a cross-disciplinary context of mediated engagement, this study analyzed how millennials consume media based on a 2019 meta-analytical research analysis of 22 cross-disciplinary studies, published between 2015 and 2019.

This research study analyzes how millennials curate and engage with digital media and information content in the midst of incessant evolutions of their identity, media use, and digital life. This study explicates six theoretical insights into how millennials consume information and engage with media. In their pursuit of easy access to media, the millennials get most of their information and media content from social media.

In theorizing how millennials engage with digital media, this study explicates important conceptual trends such as incidental news exposure (INE), which refers to people stumbling upon news stories they otherwise would not have purposefully seen or sought. INE spawns “bumpers” who involuntarily bump into news items, as opposed to “seekers” who actively search or seek news content. This leads to the news-finds-me mindset among some passive news consumers who rely and expect other active news consumers to share important news and information.

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Article

Patience Emefa Dzandza

With the emergence of ranking of universities by organizations, one major factor considered in the rankings is the intellectual output of the universities. For…

Abstract

Purpose

With the emergence of ranking of universities by organizations, one major factor considered in the rankings is the intellectual output of the universities. For universities to remain part of the global academic competitive society, intellectual output of universities can no longer be stored on shelves in libraries. Academic libraries have engaged in digitization of the intellectual works of their institutions which is a core mandate of any academic library. The purpose of this study is to ascertain the state of digitization initiatives among university libraries in Ghana.

Design/methodology/approach

A qualitative approach was adopted. Nine top universities in Ghana were selected to participate in this study. Interviews were conducted with heads of libraries.

Findings

The findings of the study revealed that seven out of the nine libraries studied have embarked on some sort of digitization initiative, and all libraries studied are using the same digital asset management system (Dspace). Major challenges reported by the participants that are common to all the libraries studied are lack of adequate and modern equipment, lack of trained personnel and lack of cooperation from faculty members.

Originality/value

This study brought fore the initiatives undertaken by academic libraries in Ghana to establish and maintain institutional repositories (IRs) amidst a number of challenges. It is a major contribution to the literature from West Africa as not much literature on IR is found from this part of the world.

Details

Collection and Curation, vol. 39 no. 3
Type: Research Article
ISSN: 2514-9326

Keywords

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