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Article
Publication date: 1 January 1991

Jose A.D. PINTO, Paulo B. COIMBRA and Carlos F.L. ANTUNES

Empirical rules and experimental evidence are not capable of dealing with both geometric complexity and nonlinearities to design a sufficient accurate, reliable and…

Abstract

Empirical rules and experimental evidence are not capable of dealing with both geometric complexity and nonlinearities to design a sufficient accurate, reliable and affordable electrical device. To minimize this gap and to achieve an high performance level in the industry design of an electromagnetic device two CAD packages (electromagnetic CAD package and thermal CAD package) working in parallel processing should be used. In this paper these two packages have been used separately. The finite element technique is used to solve the heat conduction problem in complex devices of arbitrary shape with imposed boundary conditions. As an application example, the steady‐state temperature distribution will be produced for an high voltage cross‐linked polyethylene insulated power cable. The results are discussed and the importance of such a study as an aid to improve the life expectancy of high voltage power cables is pointed out. Finally, several conclusions are suggested to increase the power cable current transmission capacity.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 1
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 8 June 2015

Hugo Neves de Melo, João P. Trovão, Carlos Henggeler Antunes, Paulo G. Pereirinha and Humberto M. Jorge

The purpose of this paper is to present a prospective study of sustainable mobility in the framework of a supporting energy management systems (EMS). Technological…

1016

Abstract

Purpose

The purpose of this paper is to present a prospective study of sustainable mobility in the framework of a supporting energy management systems (EMS). Technological advances are still required, namely electric vehicles (EV) endowed with improved EMS in order to increase their performance by making the most of available energy storage technologies. As EVs may be seen as a special domestic load, EMS are proposed based on demand-sensitive pricing strategies such as the Energy Box discussed in this paper.

Design/methodology/approach

The study presents an overview of electric mobility and an urban EV project, with special focus on the utilization of its energy sources and their relation with the energy demand of a typical urban driving cycle. Results based on the ECE 15 standard driving cycle for different free market electricity tariffs are presented.

Findings

The analysis based on present Portuguese power and energy tariffs reveals that it is highly questionable whether the resulting profit will be enough to justify the potential inconveniences to the vehicle user, as well as those resulting from the increased use of batteries.

Practical implications

The conclusions indicate that more studies on the trade-offs between grid to vehicle and vehicle to grid schemes and electricity pricing mechanisms are needed in order to understand how the utilization of EVs can become more attractive in the end-users’ and utilities’ perspectives.

Originality/value

The paper proposes an approach for future electricity tariff behavior that could be applied to EVs in order to understand whether or not their grid integration in charge and discharge situations would be beneficial for end-users and utilities, in the framework of smart energy management technologies.

Details

Management of Environmental Quality: An International Journal, vol. 26 no. 4
Type: Research Article
ISSN: 1477-7835

Keywords

Article
Publication date: 1 April 1995

JoséAmérico Dias Pinto, António Paulo Breda Coimbra and Carlos F.R. Lemos Antunes

In this paper it is proposed a thermal Finite element formulation that accommodates the current density dependency on the resistivity variation with temperature. As an…

Abstract

In this paper it is proposed a thermal Finite element formulation that accommodates the current density dependency on the resistivity variation with temperature. As an application example, the steady‐state temperature distribution will be produced for a large 3‐phase induction motor as well as the hot spot temperature for different load conditions. The results produced by the proposed Finite element approach will be compared with the solution obtained considering the current density independent of the temperature as well as with experimental data.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 27 April 2012

Pedro Neto, Nuno Mendes, Ricardo Araújo, J. Norberto Pires and A. Paulo Moreira

The purpose of this paper is to present a CAD‐based human‐robot interface that allows non‐expert users to teach a robot in a manner similar to that used by human beings to…

Abstract

Purpose

The purpose of this paper is to present a CAD‐based human‐robot interface that allows non‐expert users to teach a robot in a manner similar to that used by human beings to teach each other.

Design/methodology/approach

Intuitive robot programming is achieved by using CAD drawings to generate robot programs off‐line. Sensory feedback allows minimization of the effects of uncertainty, providing information to adjust the robot paths during robot operation.

Findings

It was found that it is possible to generate a robot program from a common CAD drawing and run it without any major concerns about calibration or CAD model accuracy.

Research limitations/implications

A limitation of the proposed system has to do with the fact that it was designed to be used for particular technological applications.

Practical implications

Since most manufacturing companies have CAD packages in their facilities today, CAD‐based robot programming may be a good option to program robots without the need for skilled robot programmers.

Originality/value

The paper proposes a new CAD‐based robot programming system. Robot programs are directly generated from a CAD drawing “running” on a commonly available 3D CAD package (Autodesk Inventor) and not from a commercial, computer aided robotics (CAR) software, making it a simple CAD integrated solution. This is a low‐cost and low‐setup time system where no advanced robot programming skills are required to operate it. In summary, robot programs are generated with a high‐level of abstraction from the robot language.

Details

Industrial Robot: An International Journal, vol. 39 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 June 1998

J.A. Dias Pinto, A. Paulo Coimbra, Paulo G. Pereirinha and C.F. Lemos Antunes

In this paper the per phase inductance and the capacitance to neutral of a 220kV three‐phase overhead transmission line are calculated using a 2D finite element…

1192

Abstract

In this paper the per phase inductance and the capacitance to neutral of a 220kV three‐phase overhead transmission line are calculated using a 2D finite element formulation. This study was performed considering the phase conductors transposition as well as the effect of the earth wires in the capacitance. The results produced by the finite element approach are compared with the analytical solutions showing a close agreement. Finally some conclusions are presented.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 28 June 2022

Dinis Daniel Santos and Paulo Gama

This paper aims to study individual managers’ market timing capabilities while trading (either buying or selling) stock from their portfolios, as well as the impact of…

Abstract

Purpose

This paper aims to study individual managers’ market timing capabilities while trading (either buying or selling) stock from their portfolios, as well as the impact of gender, seniority and trading frequency on their market timing performance.

Design/methodology/approach

This study uses a relative transaction price approach introduced by Dittmar and Field (2015) on 837 aggregated trades made by managers from their portfolios between 2010 and 2015. These were taken from publicly disclosed information through the Portuguese regulator. Furthermore, this study uses a median regression-based method to infer the authors’ conclusions.

Findings

The authors find that insiders buy (sell) at a relatively lower (higher) price when compared to other traders. This evidence shows that insiders have market timing capabilities. Moreover, this paper shows that contrarily to gender, both seniority and frequency help explain market timing performance and that insiders’ trades made over-the-counter (OTC) generally overperform the ones made on the open market (OM). Finally, this study finds a significant crisis-related influence on insiders’ market timing performance.

Originality/value

This study contributes to the literature by studying insider trading at the portfolio level, by analyzing the impact of personal characteristics of insiders (including gender, tenure and eagerness), focusing both on studying the buying and selling behavior across both OMs and OTC and analyzing firsthand the impact of a macroeconomic shift on insider trading performance.

Details

Studies in Economics and Finance, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1086-7376

Keywords

Article
Publication date: 6 July 2012

Carlos L. Antunes, Tony Richard O. Almeida, Nélia Raposeiro, Belarmino Gonçalves and Paulo Almeida

Due to its good mechanical and biocompatibility characteristics, nitinol SEMS is a popular endoprothesis used for relieving stricture problems in hollow organs due to…

Abstract

Purpose

Due to its good mechanical and biocompatibility characteristics, nitinol SEMS is a popular endoprothesis used for relieving stricture problems in hollow organs due to carcinomas. Besides its mechanical application, SEMS can be regarded as well as potential electrode for performing RF ablation therapy on the tumor. The purpose of this work is to perform numerical and experimental analyses in order to characterize the lesion volume induced in biological tissue using this kind of tubular electrode.

Design/methodology/approach

Data concerning electrical conductivity and dimension of the damaged tissue after RF ablation procedure were obtained from ex vivo samples. Next, numerical models using 3D finite element method were obtained reassembling the conditions considered at experimentation setup and results were compared.

Findings

Numerical and experimental results show that a regular volume of damaged tissue can be obtained considering this type of electrode. Also, results obtained from numerical simulation are close to those obtained by experimentation.

Originality/value

SEMSs, commonly used as devices to minimize obstruction problems due to the growth of tumors, may still be considered as an active electrode for RF ablation procedures. A method considering this observation is presented in this paper. Also, numerical simulation can be regarded in this case as a tool for determining the lesion volume.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 12 February 2018

João Barata, Paulo Rupino Da Cunha and Janusz Stal

The purpose of this paper is to identify avenues for future research in mobile supply chain management (mSCM) in the advent of Industry 4.0.

3866

Abstract

Purpose

The purpose of this paper is to identify avenues for future research in mobile supply chain management (mSCM) in the advent of Industry 4.0.

Design/methodology/approach

A systematic literature review was used to identify, classify, and analyze current knowledge, identify trends, and propose recommendations for future research.

Findings

Other research fields, such as operations, production, industrial engineering, and computer science, seem to have a head start in research into Industry 4.0. Several avenues are suggested for investigation under an information systems lens.

Research limitations/implications

Despite the care taken in the systematic literature review, the language (English), the selected keywords, and selected databases represent a natural limitation.

Practical implications

With Industry 4.0 at the top of the agenda of managers and countries, it is important to identify relevant research avenues.

Originality/value

A gap between the extant literature on mSCM and new concerns raised by Industry 4.0 is presented, and some research opportunities to close those gaps are proposed.

Details

Journal of Enterprise Information Management, vol. 31 no. 1
Type: Research Article
ISSN: 1741-0398

Keywords

Article
Publication date: 8 June 2015

F.G.A. Silva, M.F.S.F. de Moura, N Dourado, F. A. M. Pereira, J.J.L. Morais, M. I. R. Dias, Paulo J. Lourenço and Fernando M. Judas

Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and…

Abstract

Purpose

Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure concerning fracture characterization of human cortical bone under pure mode I loading.

Design/methodology/approach

A miniaturized version of the double cantilever beam (DCB) test was used for the experimental tests. A data reduction scheme based on crack equivalent concept and Timoshenko beam theory is proposed to overcome difficulties inherent to crack length monitoring during the test. The application of the method propitiates an easy determination of the Resistance-curves (R-curves) that allow to define the fracture energy under mode I loading from the plateau region. The average value of fracture energy was subsequently used in a numerical analysis with element method involving cohesive zone modelling.

Findings

The excellent agreement obtained reveals that the proposed test and associated methodology is quite effective concerning fracture characterization of human cortical bone under pure mode I loading.

Originality/value

A miniaturized version of traditional DCB test was proposed for cortical human bone fracture characterization under mode I loading owing to size restrictions imposed by human femur. In fact, DCB specimen propitiates a longer length for self-similar crack propagation without undertaking spurious effects. As a consequence, a R-curve was obtained allowing an adequate characterization of cortical bone fracture under mode I loading.

Details

International Journal of Structural Integrity, vol. 6 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Abstract

Purpose

Different from most academic publications about tourism in Brazil, this paper provides an overarching and comprehensive perspective. Analysing key developments, and focusing on the period 2000–2019, this paper also considers long-standing structural issues that hinder tourism development. Although this viewpoint paper deals with Brazil, very similar issues can be identified for many countries worldwide.

Design/methodology/approach

This viewpoint paper is a combination of reflections by leading Brazilian tourism academics; most are members of ABRATUR, the International Academy for the Development of Tourism Research in Brazil. This paper uses secondary data from the grey (e.g. government reports) and academic literature to support this opinion paper. The tourism-related topics covered in this paper include economics, policy and planning, marketing, transport, nature-based tourism, gastronomy, hospitality and education, amongst others.

Findings

Brazil has missed several unique opportunities to place it as a destination of international renown. Since the 1990s, efforts to support regional tourism development have achieved only moderate success as political instability, violence and corruption have impacted tourism. A lack of a coordinated approach between the various levels of government, a shortage of tourism data and a long-term supra-government marketing campaign, among other factors, have meant Brazil has missed several critical opportunities in the 2010s to establish itself as a leading tourism destination in the global market.

Originality/value

From leading tourism academic experts in Brazil, a unique opinion paper offers an overview of the critical development issues in 2000–2019. The paper presents matters that have hindered potential tourism contributions to the largest nation in South America. While these matters may be specific to Brazil, many of these challenges are not dissimilar to those in other emerging (democratic) nations. The authors offer several public policies and technical recommendations to scaffold tourism development towards the 2030 agenda.

设计/方法/途径

本篇观点论文是巴西前沿旅游学者们思考的集合, 其中大多数的学者是巴西旅游发展国际研究院ABRATUR的成员。这篇论文使用了诸如政府工作报告的二手数据和学术文献来支撑文章观点。其中涉及的与旅游相关的主题包括经济学, 政策和规划, 市场营销, 交通, 自然旅游, 烹饪学, 酒店, 教育等等。

目的

与巴西大多数旅游研究的出版物不同, 本文提供了一个重要且全面的视角。文章重点分析了从2000-2009年的旅游业主要发展状况, 同时考虑了阻碍旅游业发展的长期结构性问题。尽管此观点论文涉及巴西, 但在世界许多国家都可以发现非常相似的问题。

结果

巴西已经错失了作为国际知名旅游目的地的几个独特机会。二十世纪九十年代以来, 因为政治动荡, 暴力和腐败对旅游业的影响, 支持区域旅游业发展的努力仅仅取得了有限的成功。各级政府之间缺乏协调方式, 旅游数据短缺和长期的跨政府营销活动等因素, 已经意味着巴西在二十一世纪前十年已经错失了将自己在全球市场中确立为领先旅游目的地的几个重要机会。

创新/价值

这篇来源于一些巴西学术旅游届的领头羊的独特观点论文概述了从2000年到2019年巴西旅游业发展的关键问题。本文介绍了那些已经阻碍南美洲最大旅游国家潜在旅游业贡献的重要事项。尽管这些事项可能是巴西独有的, 但是其中许多问题与其他新兴的(民主的)国家也没有什么不同。我们提供了一些公共政策和技术建议, 以支持旅游业向2030年议程迈进。

Diseño/metodología/enfoque

Este artículo de opinión es una combinación de reflexiones de destacados académicos brasileños del turismo, la mayoría miembros de ABRATUR, la Academia Internacional para el Desarrollo de la Investigación en Turismo en Brasil. Se utilizan fuentes secundarias (por ejemplo, informes gubernamentales) y literatura académica para respaldar este artículo. Los temas relacionados con el turismo que se tratan en este documento incluyen economía, política y planificación, marketing, transporte, turismo basado en la naturaleza, gastronomía, hotelería, y educación, entre otros.

Propósito

A diferencia de la mayoría de las publicaciones académicas sobre el turismo en Brasil, este artículo ofrece una perspectiva global e integral. Al analizar los desarrollos clave y centrarse en 2000–2019, este documento también considera problemas estructurales de larga data que obstaculizan el desarrollo del turismo. Aunque este documento trata de Brasil, se pueden identificar problemas muy similares en muchos otros países del mundo.

Resultados

Brasil ha perdido varias oportunidades únicas para colocarse como un destino de renombre internacional. Los esfuerzos realizados desde la década de 1990 para apoyar el desarrollo del turismo regional solo han logrado un éxito moderado debido a que la inestabilidad política, la violencia y la corrupción han impactado al turismo. La falta de un enfoque coordinado entre los distintos niveles de gobierno, la escasez de datos turísticos, una campaña de marketing supra gubernamental a largo plazo, entre otros factores, han significado que Brasil haya perdido varias oportunidades críticas en la década de 2010 para establecerse como un destino turístico líder en el mercado global.

Originalidad/valor

Un artículo de opinión único de destacados expertos académicos en turismo en Brasil, que ofrece por primera vez una visión general de los problemas críticos del desarrollo desde la década del 2000. El documento presenta asuntos que han obstaculizado las posibles contribuciones del turismo a la nación más grande de América del Sur. Si bien estos asuntos pueden ser específicos de Brasil, muchos de estos desafíos no son diferentes a los de otras naciones (democráticas) emergentes. Ofrecemos diversas recomendaciones técnicas y de políticas públicas para impulsar el desarrollo turístico hacia la agenda 2030.

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