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Article
Publication date: 13 April 2018

Diogo Henrique de Bem, Daniel Petzold Barbosa Lima and Ronaldo A. Medeiros-Junior

The purpose of this paper is to verify the influence of superplasticizer and air entrainment admixtures (AEs) in the electrical resistivity of concrete.

Abstract

Purpose

The purpose of this paper is to verify the influence of superplasticizer and air entrainment admixtures (AEs) in the electrical resistivity of concrete.

Design/methodology/approach

Ten different types of concrete have been studied. Three levels of superplasticizer and air AEs have been used (0.20, 0.35 and 0.50 per cent). Concrete samples were cast and the electrical resistivity was monitored at the ages of 28, 63 and 91 days. Compressive strength and density tests have also been executed.

Findings

The superplasticizer admixture presented an optimal level of 0.35 per cent that significantly increased the electrical resistivity. The air AEs at the same dosage caused a considerable decrease in the electrical resistivity. The concrete with air AEs showed highest resistivity/MPa ratio.

Research limitations/implications

The results should be carefully extrapolated for other materials and admixtures.

Practical implications

The usage of chemicals admixture in concrete is extremely common nowadays. However, only a few authors have studied the impact of such materials on the concrete’s electrical resistivity. Since many other researchers have already correlated electrical resistivity with other concrete’s properties, such as strength, setting time and corrosion probability, it is important to better understand how superplasticizers and air-entraining agents, for instance, impact the resistivity.

Originality/value

The vast majority of studies only tested the resistivity of cement paste or mortar and usually for short period of time (up to 28 days), which seems not to be adequate since the cement reaction continues after that period. This paper fills this gap and studied the impact of admixture on concrete and for a period of 91 days.

Details

International Journal of Building Pathology and Adaptation, vol. 36 no. 2
Type: Research Article
ISSN: 2398-4708

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Article
Publication date: 27 January 2020

Raghu Babu U. and Kondraivendhan B.

Besides with a large amount of Na+ and Cl ions in seawater, the presence of Mg+2 and SO4−2 ions builds more complex corrosion mechanism. This paper aims to investigate…

Abstract

Purpose

Besides with a large amount of Na+ and Cl ions in seawater, the presence of Mg+2 and SO4−2 ions builds more complex corrosion mechanism. This paper aims to investigate the corrosion of embedded reinforcement in concrete with the environment of both Cl and SO4−2 anions associated Mg+2 cation.

Design/methodology/approach

The concrete specimens were prepared by using ordinary Portland cement (OPC), and OPC blended with metakaolin (MK) for water to cementitious material ratio (w/cm) 0.48 and 0.51. The concrete mixes were contaminated with the addition of MgCl2 alone and combined MgCl2 and MgSO4 in mix water. Reinforcement corrosion was evaluated by half-cell potential and corrosion current densities (Icorr) at regular intervals. Moreover, the influence of cementitious material type, salt type and w/cm ratio on electrical resistivity of concrete was also investigated. The statistical models were developed for electrical resistivity as a function of calcium to aluminium content ratio, compressive strength, w/cm ratio and age of concrete.

Findings

Although the corrosion initiation time increases in the concomitant presence of MgSO4 and MgCl2 as internal source compared to MgCl2, Icorr values are higher in both OPC and MK blended concrete. However, electrical resistivity decreased with addition of MgSO4. MK blended concrete performed better with increased resistivity, corrosion initiation time and decreased Icorr values.

Originality/value

This study reports statistical distributions for scattered Icorr of rebar in different concrete mixtures. Stepwise regression models were developed for resistivity by considering the interactions among different variables, which would help to estimate the resistivity through basic information.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 July 2004

A.E. Richardson

This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but…

Abstract

This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but significant difference between the electrolytic transport properties of cement grout with monofilament polypropylene fibre additions when compared to grout without fibre additions. The grout with fibre additions suggests a reduced probability of water and ion transmission, due to higher measured resistivity, which will result in enhanced durability and lower life cycle costs. Durability of reinforced concrete structures, is known to be closely linked to the water permeability of the concrete matrix. This potential trend for enhanced durability can be added to the other benefits of using monofilament polypropylene fibre in concrete, such as low absorption, freeze/thaw resistance, fire resistance and micro reinforcement.

Details

Structural Survey, vol. 22 no. 3
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 22 May 2020

Adi Susilo, Fina Fitriah, Sunaryo, Eng Turniningtyas Ayu Rachmawati and Eko Andi Suryo

Research has been conducted to analyze the landslide in Banaran area, Ponorogo Regency. The landslides occurred on April 1, 2017. This study was conducted to know the…

Abstract

Purpose

Research has been conducted to analyze the landslide in Banaran area, Ponorogo Regency. The landslides occurred on April 1, 2017. This study was conducted to know the subsurface conditions in the Banaran area to analyze the disaster mitigation efforts. The mitigation efforts are made to reduce the risk from landslides and possible landslides.

Design/methodology/approach

The method used is the geo-electric resistivity method of Wenner–Schlumberger configuration. The research was conducted in three villages namely Banaran Village, Bekirang Village and Mendak Village.

Findings

There are 12 resistivity measuring points with a track length of 410 m and a space of 10 m. The measured resistivity range is between 1.42 Ω.m and 67.500 Ω.m. The resistivity data and the local geological maps interpreted that the rocks in the Banaran area consist of clay, tuff lapilli, volcanic breccia and andesite lava. The landslide area begins at a depth of 8–35 m below the surface which is interpreted as tuff. Also, the thickness of the landslide material and the slope is = 400 which supports the occurrence of a more prominent landslide. The results of the parameter scoring of the landslide-prone areas indicated that the research area is very vulnerable to a landslide. The results of the interpretation indicate that the geo-electric resistivity method can provide a good overview for conducting landslide analysis, that is field slippage and potential material thickness occurrence landslide.

Originality/value

This article is very specific as it attempts to discover how prone Banaran are is to landslide.

Details

Smart and Sustainable Built Environment, vol. 9 no. 4
Type: Research Article
ISSN: 2046-6099

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Article
Publication date: 1 February 2004

P. Kalenda

This paper presents a method for the determination of the kinetic parameters for the oxidation‐reduction hardening reactions of unsaturated polyesters with styrene. The…

Abstract

This paper presents a method for the determination of the kinetic parameters for the oxidation‐reduction hardening reactions of unsaturated polyesters with styrene. The method was based on the measurement of the change in the specific internal electric resistance during the hardening. This paper discusses the accelerating effects of ferrocene and some of its derivatives (acetylferrocene, benzoylferrocene, 1,1′‐diethylferrocene) on the hardening of unsaturated polyesters.

Details

Pigment & Resin Technology, vol. 33 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 15 November 2011

Werner Renhart, Mario Bellina, Christian Magele and Alice Köstinger

The purpose of this paper is to achieve a very accurate localization of hidden metallic objects in human medicine applications.

Abstract

Purpose

The purpose of this paper is to achieve a very accurate localization of hidden metallic objects in human medicine applications.

Design/methodology/approach

The proposed methodology takes advantage of the eddy current effect within a metallic object. Its magnetic reaction field will be measured, e.g. with giant magnetic resistor (GMR) sensors.

Findings

A comparison of measurements and numerical results obtained by finite element computations demonstrate the reliability and positively gives a clue about the feasibility of the suggested method.

Research limitations/implications

While measuring noisy signals, the use of a lock‐in amplifier is rather expensive; especially, in applications with a high number of GMR sensors the use of channel multiplexer must be considered, which again may generate noise.

Originality/value

The paper shows how appropriate shielding of external fields in the measurement setup ensures results of satisfying quality.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 March 2016

Haibao Lu, Yongtao Yao, Jinying  Yin and Long Lin

This paper aims to study the synergistic effect of self-assembled carboxylic acid-functionalised carbon nanotube (CNT) and nafion/silica nanofibre nanopaper on the…

Abstract

Purpose

This paper aims to study the synergistic effect of self-assembled carboxylic acid-functionalised carbon nanotube (CNT) and nafion/silica nanofibre nanopaper on the electro-activated shape memory effect (SME) and shape recovery behaviour of shape memory polymer (SMP) nanocomposite.

Design/methodology/approach

Carboxylic acid-functionalised CNT and nafion/silica nanofibre are first self-assembled onto carbon fibre by means of deposition and electrospinning approaches, respectively, to form functionally graded nanopaper. The combination of carbon fibre and CNT is introduced to enable the actuation of the SME in SMP by means of Joule heating at a low electric voltage of 3.0-5.0 V.

Findings

Nafion/silica nanofibre is used to improve the shape recovery behaviour and performance of the SMP for enhanced heat transfer and electrical actuation effectiveness. Low electrical voltage actuation and high electrical actuation effectiveness of 32.5 per cent in SMP has been achieved.

Research limitations/implications

A simple way for fabricating electro-activated SMP nanocomposites has been developed by using functionally graded CNT and nafion/silica nanofibre nanopaper.

Originality/value

The outcome of this study will help to fabricate the SMP composite with high electrical actuation effectiveness under low electrical voltage actuation.

Details

Pigment & Resin Technology, vol. 45 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 December 1997

Y.M. Abu Ayana, S.M. El‐Sawy and S.H. Salah

Zinc‐ferrite pigment was prepared by solid‐state reaction. A mixture of α‐Fe2O3 and ZnO in a molar ratio of 1:1 was fired at 1,200°C. X‐ray diffraction measurements proved…

Abstract

Zinc‐ferrite pigment was prepared by solid‐state reaction. A mixture of α‐Fe2O3 and ZnO in a molar ratio of 1:1 was fired at 1,200°C. X‐ray diffraction measurements proved that the reacted material crystallized into a spinal structure. Measurement of the pigment specification and properties were carried out according to standard international methods. The pigment extract and the extract of the pigment‐linseed oil mixture were examined for use in protecting steel panels against rust. The prepared pigment was incorporated in some paint formulations. Physical, chemical and mechanical properties of the formulated paint films were studied and also tested for corrosion resistance. Finds that zinc ferrite is a basic pigment and can be recommended for use in anti‐corrosive paints. High corrosion‐resistant coatings can be obtained by incorporating zinc‐ferrite pigment in organic coating systems that cannot saponify; protection increases as the pigment‐binder ratio increases. Chemically follows up and physically emphasizes the mechanism of corrosion protection by the use of a Mossbauer spectroscope.

Details

Anti-Corrosion Methods and Materials, vol. 44 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 3 May 2016

Sangbeom Cho, Venky Sundaram, Rao Tummala and Yogendra Joshi

The functionality of personal mobile electronics continues to increase, in turn driving the demand for higher logic-to-memory bandwidth. However, the number of…

Abstract

Purpose

The functionality of personal mobile electronics continues to increase, in turn driving the demand for higher logic-to-memory bandwidth. However, the number of inputs/outputs supported by the current packaging technology is limited by the smallest achievable electrical line spacing, and the associated noise performance. Also, a growing trend in mobile systems is for the memory chips to be stacked to address the growing demand for memory bandwidth, which in turn gives rise to heat removal challenges. The glass interposer substrate is a promising packaging technology to address these emerging demands, because of its many advantages over the traditional organic substrate technology. However, glass has a fundamental limitation, namely low thermal conductivity (∼1 W/m K). The purpose of this paper is to quantify the thermal performance of glass interposer-based electronic packages by solving a multi-scale heat transfer problem for an interposer structure. Also, this paper studies the possible improvement in thermal performance by integrating a fluidic heat spreader or vapor chamber within the interposer.

Design/methodology/approach

This paper illustrates the multi-scale modeling approach applied for different components of the interposer, including Through Package Vias (TPVs) and copper traces. For geometrically intricate and repeating structures, such as interconnects and TPVs, the unit cell effective thermal conductivity approach was used. For non-repeating patterns, such as copper traces in redistribution layer, CAD drawing-based thermal resistance network analysis was used. At the end, the thermal performance of vapor chamber integrated within a glass interposer was estimated by using an enhanced effective thermal conductivity, calculated from the published thermal resistance data, in conjunction with the analytical expression for thermal resistance for a given geometry of the vapor chamber.

Findings

The limitations arising from the low thermal conductivity of glass can be addressed by using copper structures and vapor chamber technology.

Originality/value

A few reports can be found on thermal performance of glass interposers. However thermal characteristics of glass interposer with advanced cooling technology have not been reported.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 3/4
Type: Research Article
ISSN: 0961-5539

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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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