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Article
Publication date: 1 April 2006

Masahiro Inoue and Katsuaki Suganuma

This paper investigates the variations in electrical properties of a typical isotropic conductive adhesive (ICA) made with an epoxy‐based binder that are caused by…

Abstract

Purpose

This paper investigates the variations in electrical properties of a typical isotropic conductive adhesive (ICA) made with an epoxy‐based binder that are caused by differences in the curing conditions.

Design/methodology/approach

In‐situ monitoring of the various processes that were used to cure the ICA revealed that electrical conduction in the ICA specimens depends on both the high‐temperature curing conditions and the conditions during cooling to temperatures below the glass transition temperature (Tg).

Findings

The electrical resistivity of the cured ICA specimens after cooling to ambient temperature decreased with increasing degree of conversion, tending towards a convergence value that decreased with increasing curing temperature. The electrical resistivity of the specimens also varied significantly depending on the subsequent annealing process. However, the electrical resistivity achieved after annealing at temperatures above the curing temperatures clearly depended on the particular curing temperature that was used. The characteristics of the polymer structure in the adhesive binder are considered to be different, depending on the curing temperature, and this affects the electrical properties of the ICA;, i.e. the characteristics of the polymer structure obtained during the curing process affect the electrical resistance of the ICA, even after subsequent annealing processes.

Research limitations/implications

This paper discusses generalities of variation in the electrical properties of ICAs during heating and cooling processes. The variation in behaviour in practice will differ depending on the type of adhesive binder in the ICA.

Originality/value

This paper clarifies how the electrical properties of ICAs evolve during the curing, annealing and cooling processes.

Details

Soldering & Surface Mount Technology, vol. 18 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 25 July 2008

Olubola Babalola and David Abiodun Adesanya

Electrical services contribute a substantial percentage of total construction cost of any particular project. It is essential for estimators to have a detailed knowledge…

Abstract

Purpose

Electrical services contribute a substantial percentage of total construction cost of any particular project. It is essential for estimators to have a detailed knowledge of the factors that affect the incorporation of electrical services cost into the overall building project cost. The overall aim of the study that formed the basis for this paper therefore was to investigate the factors that influence cost estimating of electrical services project.

Design/methodology/approach

The study was carried out based on questionnaire survey of 225 organizations that are involved in cost estimating of electrical services projects in Nigeria. A total of 158 questionnaires out of the 163 retrieved were appropriate for analysis. A list of factors potentially influencing cost estimate for electrical services was identified for the respondents to rate. The data collected were analyzed using factor analysis based on principal component analysis and varimax orthogonal rotation.

Findings

The results shows that the factors affecting production of cost estimate for electrical services could be grouped into four principal factors: the most important factor grouping being estimator competence followed by project technicality, economic requirements and contract requirements.

Practical implications

Many factors are considered by practitioners in the preparation of cost estimate for electrical work in construction project development. The paper has listed about 23 factors that are relevant. However, this paper has shown that four principal factors need to be considered as they explain 64 percent of the factors affect cost estimate production for building project's electrical service works.

Originality/value

Review of literature has shown that there is limited empirical research on the factors influencing cost estimate production for electrical services work. The paper has produced an empirical research on the crucial factors that must be taken into account when producing cost estimate for the electrical service projects.

Details

Journal of Financial Management of Property and Construction, vol. 13 no. 3
Type: Research Article
ISSN: 1366-4387

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Article
Publication date: 28 December 2020

Suwimon Saneewong Na Ayuttaya

This study aims to present a numerical analysis of the behavior of the electric field and flow field characteristics under electrohydrodynamics (EHD) force. The influence…

Abstract

Purpose

This study aims to present a numerical analysis of the behavior of the electric field and flow field characteristics under electrohydrodynamics (EHD) force. The influence of the jet airflow under the EHD force is investigated when it impacts the inclined flat plate.

Design/methodology/approach

The high electrical voltage and angle of an inclined flat plate are tested in a range of 0–30 kV and 0–90°, respectively. In this condition, the air is set in a porous medium and the inlet jet airflow is varied from 0–2 m/s.

Findings

The results of this study show that the electric field line patterns increase with increasing the electrical voltage and it affects the electric force increasing. The angle of inclined flat plate and the boundary of the computational model are influenced by the electric field line patterns and electrical voltage surface. The electric field pattern is the difference in the fluid flow pattern. The fluid flow is more expanded and more concentrated with increasing the angle of an inclined flat plate, the electrical voltage and the inlet jet airflow. The velocity field ratio is increased with increasing the electrical voltage but it is decreased with increasing the angle of the inclined flat plate and the inlet jet airflow.

Originality/value

The maximum Reynolds number, the maximum velocity field and the maximum cell Reynolds number are increased with increasing the electrical voltage, the inlet jet airflow and the angle of the inclined flat plate. In addition, the cell Reynolds number characteristics are more concentrated and more expanded with increasing the electrical voltage. The pattern of numerical results from the cell Reynolds number characteristics is similar to the pattern of the fluid flow characteristics. Finally, a similar trend of the maximum velocity field has appeared for experimental and numerical results so both techniques are in good agreement.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 7
Type: Research Article
ISSN: 0961-5539

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Book part
Publication date: 18 June 2004

Daniel F Jennings and Kevin G Hindle

Zahra and Covin (1995, p. 46) report that “the current interest in corporate entrepreneurship arises from its potential usefulness as a means for renewing established…

Abstract

Zahra and Covin (1995, p. 46) report that “the current interest in corporate entrepreneurship arises from its potential usefulness as a means for renewing established organizations and increasing their ability to compete in their chosen markets.” In addition, a number of researchers support a contention made by Schollhamer (1982, p. 82), that “corporate entrepreneurship is a key element for gaining competitive advantage and consequently greater financial strength” (Covin & Slevin, 1991; Peters & Waterman, 1982; Zahra & Covin, 1995). Interestingly, however, other researchers argue that corporate entrepreneurship can be risky and may be detrimental to a firm’s short-term financial performance (Burgelman & Scales, 1986; Fast, 1981).

Details

Advances in Entrepreneurship, Firm Emergence and Growth
Type: Book
ISBN: 978-1-84950-267-2

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Article
Publication date: 6 May 2020

Yassine Bouteraa, Ismail Ben Abdallah and Ahmed Elmogy

The purpose of this paper is to design and develop a new robotic device for the rehabilitation of the upper limbs. The authors are focusing on a new symmetrical robot…

Abstract

Purpose

The purpose of this paper is to design and develop a new robotic device for the rehabilitation of the upper limbs. The authors are focusing on a new symmetrical robot which can be used to rehabilitate the right upper limb and the left upper limb. The robotic arm can be automatically extended or reduced depending on the measurements of the patient's arm. The main idea is to integrate electrical stimulation into motor rehabilitation by robot. The goal is to provide automatic electrical stimulation based on muscle status during the rehabilitation process.

Design/methodology/approach

The developed robotic arm can be automatically extended or reduced depending on the measurements of the patient's arm. The system merges two rehabilitation strategies: motor rehabilitation and electrical stimulation. The goal is to take the advantages of both approaches. Electrical stimulation is often used for building muscle through endurance, resistance and strength exercises. However, in the proposed approach the electrical stimulation is used for recovery, relaxation and pain relief. In addition, the device includes an electromyography (EMG) muscle sensor that records muscle activity in real time. The control architecture provides the ability to automatically activate the appropriate stimulation mode based on the acquired EMG signal. The system software provides two modes for stimulation activation: the manual preset mode and the EMG driven mode. The program ensures traceability and provides the ability to issue a patient status monitoring report.

Findings

The developed robotic device is symmetrical and reconfigurable. The presented rehabilitation system includes a muscle stimulator associated with the robot to improve the quality of the rehabilitation process. The integration of neuromuscular electrical stimulation into the physical rehabilitation process offers effective rehabilitation sessions for neuromuscular recovery of the upper limb. A laboratory-made stimulator is developed to generate three modes of stimulation: pain relief, massage and relaxation. Through the control software interface, the physiotherapist can set the exercise movement parameters, define the stimulation mode and record the patient training in real time.

Research limitations/implications

There are certain constraints when applying the proposed method, such as the sensitivity of the acquired EMG signals. This involves the use of professional equipment and mainly the implementation of sophisticated algorithms for signal extraction.

Practical implications

Functional electrical stimulation and robot-based motor rehabilitation are the most important technologies applied in post-stroke rehabilitation. The main objective of integrating robots into the rehabilitation process is to compensate for the functions lost in people with physical disabilities. The stimulation technique can be used for recovery, relaxation and drainage and pain relief. In this context, the idea is to integrate electrical stimulation into motor rehabilitation based on a robot to obtain the advantages of the two approaches to further improve the rehabilitation process. The introduction of this type of robot also makes it possible to develop new exciting assistance devices.

Originality/value

The proposed design is symmetrical, reconfigurable and light, covering all the joints of the upper limbs and their movements. In addition, the developed platform is inexpensive and a portable solution based on open source hardware platforms which opens the way to more extensions and developments. Electrical stimulation is often used to improve motor function and restore loss of function. However, the main objective behind the proposed stimulation in this paper is to recover after effort. The novelty of the proposed solution is to integrate the electrical stimulation powered by EMG in robotic rehabilitation.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 2 April 2020

Delfim Soares, Manuel Sarmento, Daniel Barros, Helder Peixoto, Hugo Figueiredo, Ricardo Alves, Isabel Delgado, José C. Teixeira and Fátima Cerqueira

This study aims to investigate the effect of bismuth addition (up to 30 Wt%) on the microstructure and electrical conductivity of a commercial lead-free alloy (SAC405…

Abstract

Purpose

This study aims to investigate the effect of bismuth addition (up to 30 Wt%) on the microstructure and electrical conductivity of a commercial lead-free alloy (SAC405) near the solder/substrate soldered joint. The system under study is referred in this work as (SAC405 + xBi)/Cu, as Cu is the selected substrate in which the solder was casted. The electrical resistivity of this system was investigated, considering Bi addition effect on the local microstructure and chemical composition gradients within that zone.

Design/methodology/approach

Solder joints between Cu substrate and SAC405 alloy with different levels of Bi were produced. The electrical conductivity along the obtained solder/substrate interface was measured by four-point probe method. The microstructure and chemical compositions were evaluated by scanning electron microscopy/energy dispersive spectroscopy analysis.

Findings

Two different electrical resistivity zones were identified within the solder interface copper substrate/solder alloy. At the first zone (from intermetallic compound [IMC] until approximately 100 μm) the increase of the electrical resistivity is gradual from the substrate to the solder side. This is because of the copper substrate diffusion, which established a chemical composition gradient near the IMC layer. At the second zone, electrical resistivity becomes much higher and is mainly dependent on the Bi content of the solder alloy. In both identified zones, electrical resistivity is affected by its microstructure, which is dependent on Cu and Bi content and solidification characteristics.

Originality/value

A detailed characterization of the solder/substrate zone, in terms of electrical conductivity, was done with the definition of two variation zones. With this knowledge, a better definition of processing parameters and in-service soldered electronic devices behavior can be achieved.

Details

Soldering & Surface Mount Technology, vol. 33 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 1 June 2005

Dubravko Rogale, Igor Petrunić, Zvonko Dragčević and Snježana Firšt Rogale

The equipment for computerised measuring of electrical power and energy is presented, adapted to the needs of investigating processing parameters of garment sewing operations.

Abstract

Purpose

The equipment for computerised measuring of electrical power and energy is presented, adapted to the needs of investigating processing parameters of garment sewing operations.

Design/methodology/approach

The method of measuring the energy necessary to run the sewing‐machine driving electrical motor is also presented, correlated to the stitching speed in joining a straight seam in a single, two, or three, segments. Electrical energy consumption is analysed as dependent on the stitching speed, varying the number of stitches in the seam.

Findings

The investigations described have shown the impact of the method of work applied and the effect of the changes in garment sewing operation in processing parameters on the level of electrical energy consumed by the sewing‐machine drive electrical motor. A new measuring method has been introduced in garment engineering, aimed at predicting electrical energy consumption in garment sewing operations, thus opening a completely new field of investigation in the area of garment technologies.

Originality/value

A method of calculating the energy processing parameters of sewing operations.

Details

International Journal of Clothing Science and Technology, vol. 17 no. 3/4
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 17 October 2008

Mei Li, Wen‐Bo Wei, Ming Deng, Wen‐Ju Yuan and Qi‐Sheng Zhang

The aim is to apply pseudo‐random correlation method to detect very weak electrical signals because of various natural and artificial electron‐magnetic interferences in…

Abstract

Purpose

The aim is to apply pseudo‐random correlation method to detect very weak electrical signals because of various natural and artificial electron‐magnetic interferences in electrical prospecting.

Design/methodology/approach

Electrical prospecting is an important method of geophysical exploration and the electrical prospecting instruments are required to detect very weak electrical signals against strong interferences. Recently, pseudo‐random correlation coding has been widely applied in telecommunications and measurement and test systems to improve the signal noise ratio with great success, but has not been used in electric prospecting. This paper theoretically investigated the application model of pseudo‐random correlation techniques in electrical prospecting.

Findings

The model of pseudo‐random correlation techniques in electrical prospecting, including its principle, detailed protocol and parameter selection, is established.

Practical implications

With the continuing improvement in the capacity of electrical prospecting transmitters, the pseudo‐random correlation method will be widely used in electrical prospecting.

Originality/value

The pseudo‐random correlation techniques is originally investigated for its application in electrical prospecting. This paper is aimed at researchers and engineers in geophysical exploration.

Details

Kybernetes, vol. 37 no. 9/10
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 2 May 2017

Jan Karthaus, Simon Steentjes, Nora Leuning and Kay Hameyer

The purpose of this paper is to study the variation of the specific iron loss components of electrical steel sheets when applying a tensile mechanical load below the yield…

Abstract

Purpose

The purpose of this paper is to study the variation of the specific iron loss components of electrical steel sheets when applying a tensile mechanical load below the yield strength of the material. The results provide an insight into the iron loss behaviour of the laminated core of electrical machines which are exposed to mechanical stresses of diverse origins.

Design/methodology/approach

The specific iron losses of electrical steel sheets are measured using a standardised single-sheet tester equipped with a hydraulic pressure cylinder which enables application of a force to the specimen under test. Based on the measured data and a semi-physical description of specific iron losses, the stress-dependency of the iron loss components can be studied.

Findings

The results show a dependency of iron loss components on the applied mechanical stress. Especially for the non-linear loss component and high frequencies, a large variation is observed, while the excess loss component is not as sensitive to high mechanical stresses. Besides, it is shown that the stress-dependent iron loss prediction approximates the measured specific iron losses in an adequate way.

Originality/value

New applications such as high-speed traction drives in electric vehicles require a suitable design of the electrical machine. These applications require particular attention to the interaction between mechanical influences and magnetic behaviour of the machine. In this regard, knowledge about the relation between mechanical stress and magnetic properties of soft magnetic material is essential for an exact estimation of the machine’s behaviour.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 6 November 2017

Jingsong Li, Lixiang Wang, Qingxin Yang, Shanming Wang, Yongjian Li, Changgeng Zhang and Baojun Qu

Due to existence of skin effect under rotational excitation, especially to high-frequency motors and power transformers run at the frequency of hundreds or even thousands…

Abstract

Purpose

Due to existence of skin effect under rotational excitation, especially to high-frequency motors and power transformers run at the frequency of hundreds or even thousands of hertz, core losses will increase significantly, which may cause local overheating damage, and the efficiency and longevity will be decreased. The purpose of this paper is to accurately calculate the rotational anomalous loss in electrical steel sheets.

Design/methodology/approach

The influence of skin effect to rotational anomalous loss coefficient is described in detail. Based on the rotational core losses calculation approach, the transformed coefficient and parameters of rotational anomalous loss are determined in accordance with experimental data obtained by using 3D magnetic properties testing system. Then, a variable loss coefficient calculation model of rotational anomalous loss is built. Meanwhile, a separation of the total 2D elliptical rotation experimental core losses is worked out.

Findings

The two methods are analysed and compared qualitatively. It should be noted that the novel calculation model can be more effectively presented anomalous loss features. Moreover, quantitative comparisons between 2D elliptical rotation and alternating core losses have achieved beneficial conclusions.

Originality/value

Transformed rotational anomalous loss coefficient and parameters of electrical steel sheets considering skin effect are determined. Based on that, a novel calculation model evaluating 2D elliptical rotation anomalous loss is presented and verified based on the experimental measurement and the separation of the total 2D elliptical rotation core losses. The 2D elliptical rotation core losses separation method and quantitative comparison with alternating excitation are helpful to engineering application.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

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