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Article
Publication date: 5 March 2010

Keiji Houjou, Kotoji Ando and Koji Takahashi

Zirconia ceramics exhibit high strength and fracture toughness. The purpose of this paper is to research a possibility of crack healing in zirconia ceramics.

Abstract

Purpose

Zirconia ceramics exhibit high strength and fracture toughness. The purpose of this paper is to research a possibility of crack healing in zirconia ceramics.

Design/methodology/approach

ZrO2/SiC composite ceramics are sintered and subjected to three‐point bending. A surface crack of 100 μm in diameter is formed on each specimen. The cracks are healed and the specimens are tested under bending.

Findings

The paper finds that ZrO2/SiC composite ceramic material had a high crack‐healing ability at a considerably low temperature. For example, a crack of 100 μm in diameter is healed even at 600°C.

Research limitations/implications

The paper provides a low temperature healing and a new mechanism of crack healing.

Originality/value

The paper shows the healing temperature and the minimum time required to heal showed a good proportional relation on the Arrhenius plot at temperatures of 600‐800°C. Moreover, the crack healing is caused by SiO2 cristobalite produced during the healing.

Details

International Journal of Structural Integrity, vol. 1 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 2 March 2012

Keiji Houjou and Koji Takahashi

The purpose of this paper is to study the crack‐healing mechanism of ZrO2/SiC composite ceramics which have a high crack‐healing ability at low temperature.

Abstract

Purpose

The purpose of this paper is to study the crack‐healing mechanism of ZrO2/SiC composite ceramics which have a high crack‐healing ability at low temperature.

Design/methodology/approach

The effects of dispersed SiC and the environment on crack‐healing behaviour were investigated. The fatigue strength of crack‐healed specimens was also investigated.

Findings

The main conclusions are that for crack‐healing of ZrO2 ceramics, it is necessary to have both a SiC composite and an oxidative environment; and when ZrO2/SiC composite ceramics are heat‐treated in air, a phase transformation attributable to the SiC composite results in crack‐healing and improvement of fracture toughness and bending strength.

Originality/value

An appropriate heat treatment for ZrO2/SiC composite caused not only crack‐healing but also the improvement of fracture toughness, and created a multiplier effect on crack‐healing, bending strength and fracture toughness.

Details

International Journal of Structural Integrity, vol. 3 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 2 June 2022

Jan Resenga Maluleka and Marcia Nkwe

This study aims to investigate the indigenous healing space in South Africa, by zooming in on the confusions that are faced by young people in the country. These muddles…

Abstract

Purpose

This study aims to investigate the indigenous healing space in South Africa, by zooming in on the confusions that are faced by young people in the country. These muddles are a result of the country’s colonial and apartheid history which left the population divided between the Western and African philosophies when it comes to health among other things. The recent technological developments which are embraced by some of the healers exposed the space to exploitation by criminal elements.

Design/methodology/approach

This qualitative study used content analysis and interviews to gather data.

Findings

The results suggest that the indigenous healing space in South Africa is poorly regulated and a fertile breeding ground for criminals. As a result, it is not easy to distinguish between genuine healers and bogus ones. The technological advancement, especially social media, has exposed the space to further exploitation by criminal elements.

Originality/value

This study paints a picture of the indigenous healing space in the age of technology in South Africa. This study further explains challenges faced by South Africans in navigating philosophical challenges influenced by their colonial past.

Details

Global Knowledge, Memory and Communication, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2514-9342

Keywords

Book part
Publication date: 12 February 2013

Claire Laurier Decoteau

Sociologists have tended to construct theories of identity based on unitary notions of social location which avoid conceptualizing disjunction and contradiction and which…

Abstract

Sociologists have tended to construct theories of identity based on unitary notions of social location which avoid conceptualizing disjunction and contradiction and which therefore fail to capture certain characteristics of the postcolonial condition. This paper engages in a postcolonial re-reading of sociological theories of practice (in particular, Pierre Bourdieu's notion of habitus). It does so through an analysis of the historical development of the field of health and healing in South Africa. From the beginning of the colonial enterprise, biomedicine resisted amalgamation with other forms of healing and insisted on a monotherapeutic ideology and practice whereas indigenous healing accommodated not only biomedicine, but invited pluralism within and across cultural and ethnic differences. As such, a bifurcated and parallel system of healing emerged, whereby Black South Africans practiced pluralism and white South Africans utilized biomedicine in isolation. This disjuncture became acrimonious in the post-apartheid era as the state attempted to forge a united health system and battle the AIDS epidemic. Despite the historical and contemporary bifurcations within the field of health and healing, people living with AIDS continue to subscribe to a hybrid health ideology. There is, therefore, a structural disjuncture between the realities of consumption within the field of health and healing and the logic of the field as it is articulated in the symbolic struggle raging in the field of power. The field of health and healing is characterized, therefore, by a simultaneous bifurcation and hybridity – which is reflected in HIV-infected South Africans’ beliefs and practices. In order to make sense of this puzzling disjuncture and its impact on subjects’ trajectories of action, this paper draws insight from Pierre Bourdieu's theory of habitus and Homi Bhabha's conceptualization of hybridity – transforming each of them through their synthesis and application to the postcolonial context.

Details

Postcolonial Sociology
Type: Book
ISBN: 978-1-78190-603-3

Book part
Publication date: 16 August 2021

M. Susanne Schotanus

Since Barker, Gupta, and Iantaffi (2007), in both mainstream cultural products and academic literature dealing with BDSM, there has been an increase in emanations of the …

Abstract

Since Barker, Gupta, and Iantaffi (2007), in both mainstream cultural products and academic literature dealing with BDSM, there has been an increase in emanations of the “healing narrative,” which suggests that BDSM practices offer therapeutic potential. However, no significant attempt has been made to explore in greater detail the problematic relationship between this healing narrative and the history of pathologization of sadomasochistic desires and practices. Barker et al. (2007) rightly point out that in suggesting BDSM has healing potential, one runs the risk of implying that individuals who practice BDSM are in need of healing to begin with. This could be damaging to the image of BDSM, which after centuries of pathologization finally appears to be moving into a realm of acceptability. However, the experiences of BDSM practitioners who describe their practices as healing should not be discounted and could actually help to cultivate a more positive reputation, which makes the issue a political one. In this chapter, through an exploration of the concept of “healing” in cultural objects such as the film Secretary (2002, directed by Steven Shainberg) and the Showtime cable television series Billions (2016–present), this issue will be investigated further, leading to a way out of the apparent double bind. The aim is to come to an understanding of the therapeutic potential of BDSM, which would not only reframe the discourse of pathologization surrounding BDSM but also further the political goal of creating space for BDSM practitioners to explore their desires without having to experience stigmatization.

Article
Publication date: 7 October 2021

Dibyendu Adak, Donkupar Francis Marbaniang and Subhrajit Dutta

Self-healing concrete is a revolutionary building material that will generally reduce the maintenance cost of concrete constructions. Self-healing of cracks in concrete…

Abstract

Purpose

Self-healing concrete is a revolutionary building material that will generally reduce the maintenance cost of concrete constructions. Self-healing of cracks in concrete structure would contribute to a longer service life of the concrete and would make the material more durable and more sustainable. The cementitious mortar with/without incorporating encapsulates at different percentages of slag replacement with the cement mix improves autogenous healing at different ages. Therefore, this study’s aim is to develop a self-healing cementitious matrix for repair and retrofitting of concrete structures.

Design/methodology/approach

In the present work, waste straw pipes are used as a capsule, filled with the solution of sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and colloidal nano-silica as self-healing activators. An artificial micro-crack on the control and blended mortar specimens at different percentages of slag replacement with cement (with/without encapsulation) is developed by applying a compressive load of 50% of its ultimate load-carrying capacity. The mechanical strength and ultrasonic pulse velocity, water absorption and chloride ion penetration test are conducted on the concrete specimen before and after the healing period. Finally, the self-healing activity of mortar mixes with/without encapsulation is analysed at different ages.

Findings

The encapsulated mortar mix with 10% of slag content has better self-healing potential than all other mixes considering mechanical strength and durability. The enhancement of the self-healing potential of such mortar mix is mainly due to hydration of anhydrous slag on the crack surface and transformation of amorphous slag to the crystalline phase in presence of encapsulated fluid.

Research limitations/implications

The self-healing activities of the slag-based cementitious composite are studied for a healing period of 90 days only. The strength and durability performance of the cracked specimen may be increased after a long healing period.

Practical implications

The outcome of the work will help repair the cracks in the concrete structure and enhances the service life.

Originality/value

This study identifies the addition encapsulates with a self-healing activator fluid that can recover its strength after minor damage.

Details

International Journal of Structural Integrity, vol. 12 no. 5
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 2 January 2018

Hongsheng Luo, Xingdong Zhou, Yuncheng Xu, Huaquan Wang, Yongtao Yao, Guobin Yi and Zhifeng Hao

This paper aims to exploit shape-memory polymers as self-healable materials. The underlying mechanism involved the thermal transitions as well as the enrichment of the…

Abstract

Purpose

This paper aims to exploit shape-memory polymers as self-healable materials. The underlying mechanism involved the thermal transitions as well as the enrichment of the healing reagents and the closure of the crack surfaces due to shape recovery. The multi-stimuli-triggered shape memory composite was capable of self-healing under not only direct thermal but also electrical stimulations.

Design/methodology/approach

The shape memory epoxy polymer composites comprising the AgNWs and poly (ε-caprolactone) were fabricated by dry transfer process. The morphologies of the composites were investigated by the optical microscope and scanning electron microscopy (SEM). The electrical conduction and the Joule heating effect were measured. Furthermore, the healing efficiency under the different stimuli was calculated, whose dependence on the compositions was also discussed.

Findings

The AgNWs network maintained most of the pathways for the electrons transportation after the dry transfer process, leading to a superior conduction and flexibility. Consequently, the composites could trigger the healing within several minutes, as applied with relatively low voltages. It was found that the composites having more the AgNWs content had better electrically triggered performance, while 50 per cent poly (ε-caprolactone) content endowed the materials with max healing efficiency under thermal or electrical stimuli.

Research limitations/implications

The findings may greatly benefit the application of the intelligent polymers in the fields of the multifunctional flexible electronics.

Originality/value

Most studies have by far emphasized on the direct thermal triggered cases. Herein, a novel, flexible and conductive shape memory-based composite, which was capable of self-healing under the thermal or electrical stimulations, has been proposed.

Details

Pigment & Resin Technology, vol. 47 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 3 December 2018

Panagiota Polydoropoulou, Christos Vasilios Katsiropoulos, Andreas Loukopoulos and Spiros Pantelakis

Over the last decades, self-healing materials based on polymers are attracting increasing interest due to their potential for detecting and “autonomically” healing damage…

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Abstract

Purpose

Over the last decades, self-healing materials based on polymers are attracting increasing interest due to their potential for detecting and “autonomically” healing damage. The use of embedded self-healing microcapsules represents one of the most popular self-healing concepts. Yet, extensive investigations are still needed to convince on the efficiency of the above concept. The paper aims to discuss these issues.

Design/methodology/approach

In the present work, the effect of embedded self-healing microcapsules on the ILSS behavior of carbon fiber reinforced composite materials has been studied. Moreover, the self-healing efficiency has been assessed. The results of the mechanical tests were discussed supported by scanning electron microscope (SEM) as well as by Attenuated Total Reflection–Fourier-transform infrared spectroscopy (ATR–FTIR) analyses.

Findings

The results indicate a general trend of a degraded mechanical behavior of the enhanced materials, as the microcapsules exhibit a non-uniform dispersion and form agglomerations which act as internal defects. A remarkable value of the self-healing efficiency has been found for materials with limited damage, e.g. matrix micro-cracks. However, for significant damage, in terms of large matrix cracks and delaminations as well as fiber breakages, the self-healing efficiency is limited.

Originality/value

The results obtained by SEM analysis as well as by ATR–FTIR spectroscopy constitute a strong indication that the self-healing mechanism has been activated. However, further investigation should be conducted in order to provide definite evidence.

Details

International Journal of Structural Integrity, vol. 9 no. 6
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 6 March 2017

Mehdi Shahidi Zandi and Majdeh Hasanzadeh

The aim of this work is to investigate the self-healing performance of epoxy coatings containing microcapsules. The microcapsule-based coatings were applied on AA6061 Al…

Abstract

Purpose

The aim of this work is to investigate the self-healing performance of epoxy coatings containing microcapsules. The microcapsule-based coatings were applied on AA6061 Al alloy and immersed in 3.5 per cent NaCl solution.

Design/methodology/approach

Microcapsules with urea–formaldehyde as the shell and linseed oil as the healing agent were prepared by in situ polymerization in an oil-in-water emulsion. For the sake of an optimum self-healing system, some coating samples were prepared by using different microcapsule concentrations: 0, 5, 10 and 20 Wt.%. The scratch-filling efficiency as the theoretical estimate of the self-healing performance was calculated for the coating samples with different microcapsule concentrations. The scratch-sealing efficiency (SSE) as a particularly crucial parameter in the self-healing evaluation of coatings was measured by both electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques.

Findings

According to EIS and EN results, the coating samples containing 5 and 10 per cent microcapsules provided the insignificant self-healing performance, while the coating sample containing 20 per cent microcapsules exhibited the acceptable self-healing performance to AA6061 alloy in the NaCl solution. The measured SSE values confirmed the good agreement of EN data with electrochemical parameters obtained from the EIS technique.

Originality/value

This work is an attempt to evaluate the self-healing performance of microcapsule-based epoxy coatings applied on AA6061 Al alloy in sea water.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 9 November 2015

Jae Yeon Yang, Soyon Paek, Taegoo (Terry) Kim and Tae Hee Lee

The purpose of this study is to explore the effect of tourists’ needs for healing experience (NHE) on behavioral intentions for transformation (BIT) with healing

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Abstract

Purpose

The purpose of this study is to explore the effect of tourists’ needs for healing experience (NHE) on behavioral intentions for transformation (BIT) with healing involvement (HI) as a mediator. Using the two sub-constructs of BIT in the tourism industry (i.e. selection of healing tour products and transformational intention of healing tour behavior), this study evaluates BIT.

Design/methodology/approach

The survey was administered to visitors in healing resorts/centers in Korea; 383 completed surveys were used to investigate the hypothesized relationships of this study using regression analysis.

Findings

The study results confirmed the hypothesized relationships: the positive effects of NHE on BIT and the significant mediating role of HI in the relationships between NHE and BIT.

Practical implications

The relationships among NHE, HI and BIT can improve the understanding and practices of healing experience and the development of healing products in the tourism industry. This study offers a meaningful and extended perspective on customers’ experience and product development by interpreting customers’ desires and needs.

Originality/value

This study explores the under-researched subject of NHE and HI from a transformative economic perspective. The study is among the first to examine the structural relationships among NHE, HI and BIT. The uniqueness of the study is highlighted by the use of two sub-dimensions of the BIT industry (i.e. selection of healing tour products and transformational intention of healing tour behavior) in a tourism context.

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