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Article
Publication date: 21 August 2007

J. Landa, I. Illarramendi, N. Kelling, M. Woydt, A. Skopp and M. Hartelt

This paper aims to focus on the potential for substituting molybdenum‐based piston ring coatings, which are recognized as “allrounder” by other candidate metallurgies. Another…

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Abstract

Purpose

This paper aims to focus on the potential for substituting molybdenum‐based piston ring coatings, which are recognized as “allrounder” by other candidate metallurgies. Another purpose is the tribological interaction of molybdenum‐based and new triboactive/reactive piston ring coatings with low SAP, polymer‐ and metal‐free as well as bionotox engine oils with high‐viscosity indices.

Design/methodology/approach

Substoichiometric titanium dioxide composed of the Magnéli‐types phases Ti4O7 (∼17 per cent), Ti5O9 (∼66 per cent), Ti6O11 (∼17 per cent) deposited by plasma spraying, a vacuum sprayed TiO1,93 and a plasma‐sprayed titanium‐molybdenum carbo‐nitride coated piston rings were compared to a state‐of‐the‐art molybdenum‐based piston ring. They were tribologically characterized by means of BAM and SRV tests lubed under mixed/boundary lubrication by factory fill engine oils, engine oils as blends of hydro‐carbons with esters as well as prototype engine oils based on esters and polyglycols.

Findings

Overall, the molybdenum‐ and titanium‐based ring coatings wore in the same order of magnitude. The ranking depends on the test used. The BAM test favours MKP81A (PL72) more, whereas the SRV methods favour the TinO2n−1 more. The different bionotox and low‐ash prototype engine oils with reduced additive contents displayed isoperformance regarding the tribological behaviour of common and triboreactive materials. They presented no visible weakness in wear resistance, coefficient of friction and extreme pressure properties.

Research limitations/implications

The next steps have to confirm functional properties by different engine and endurance tests.

Practical implications

Titanium‐based piston ring coatings are overall more attractive, as they are primarily refined from titania, which is cheap and not rated at stock exchanges, and they present at least an isoperformance when compared with molybdenum‐based ring coatings.

Originality/value

This supplier report displays the complete methodology in order to substitute molybdenum‐ by titanium‐based piston ring coatings as well as illuminating the beneficial interaction with alternative engine oils in existing engine architectures.

Details

Industrial Lubrication and Tribology, vol. 59 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 8 February 2008

Mathias Woydt, Bernard Criqui, Gérard Desplanches and Tom Linneman

The purpose of this paper is to underline the future need for OEMs to receive lowSAP, polymer‐ and metal‐free engine oils with high‐viscosity indices and to illuminate for other…

522

Abstract

Purpose

The purpose of this paper is to underline the future need for OEMs to receive lowSAP, polymer‐ and metal‐free engine oils with high‐viscosity indices and to illuminate for other OEMs the technical feasibility for application of alternative engine oils based on esters or blends of hydrocarbons with esters or polyglycols.

Design/methodology/approach

The strategic goal depends technically on the use of intrinsic properties of alternative base fluids, thus substituing some additives, like anti‐wear, extreme pressure and viscosity index improvers. The prone wear resistance of novel triboactive/‐reactive materials enables higher portions of mixed/boundary lubrication generated by oils with a lower viscosity.

Findings

Overall, the different bionotox and low‐ash prototype engine oils with reduced additive contents displayed isoperformance regarding the tribological behaviour against cast iron and triboreactive materials. APS‐Tin−2Cr2O2n−1 displayed an overall wear resistance comparable with grey cast iron with high‐carbon content and liner wear reduction of one order of magnitude when mated with Mo‐based rings. Both tests confirmed the potential for substituing molybdenum‐based rings by APS‐Tin−2Cr2O2n−1. The most significant reduction in “system wear” down to “zero wear” was demonstrated by mating the APS‐Tin−2Cr2O2n−1 coated piston rings with smooth machined HVOF‐(Ti,Mo)(C,N) liner coatings.

Research limitations/implications

As lubricants are today not part of the core business of automotive OEMs, the next steps have to be proposed by the petrochemical suppliers. It is recalled here that some OEMs in their history developed and produced lubricants.

Practical implications

The customer will appreciate any increase in longevity resulting in reduced maintenance. The OEM now owns, under increased solicitations, now a future‐oriented tool box in order to respond to environmental and CAFÉ demands with reasonable cost management.

Originality/value

This OEM report displays the complete methodology in order to adopt alternative engine oils in existing engine architectures.

Details

Industrial Lubrication and Tribology, vol. 60 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 October 2003

Mathias Woydt and Norbert Kelling

The test procedure for characterizing the tribological behavior of lubricants and materials for the system “piston ring/cylinder liner” outside of engines is now operational and…

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Abstract

The test procedure for characterizing the tribological behavior of lubricants and materials for the system “piston ring/cylinder liner” outside of engines is now operational and validated. The test parameters presented in this paper (FN=50 N; v=0.3 m/s, s=24 km) may act only as an indicator and should be used to the tasks regarded. It allows the check prior expensive engine testing, if a tribomaterial, tribocouple or new lubricant will reach a satisfactory engine performance. The introduction of piston ring segments and cylinder liner as specimen into the test rig as well as the volumetric wear determined by means of stylus profilometry represented a big step forward in order to increase the transferability of “tribotests” to engine tests on an acceptable level.

Details

Industrial Lubrication and Tribology, vol. 55 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 12 February 2025

Nicolle A. Montgomery

Although the literature on modern slavery (MS) is continually increasing, there remains a paucity of theory-driven research. Hence, this study aims to develop a multitheoretical…

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Abstract

Purpose

Although the literature on modern slavery (MS) is continually increasing, there remains a paucity of theory-driven research. Hence, this study aims to develop a multitheoretical framework and research agenda for MS.

Design/methodology/approach

This study comprised two steps. First, it reviews the literature on supply chain (SC) social sustainability to identify the typically used theories. Six of them were selected for this study: institutional, stakeholder, resource-based, resource dependence, principal agent and transaction cost economics theories. Second, it conducts a systematic literature review using the preferred reporting items for systematic reviews and meta-analyses guidelines to analyze relevant literature on social issues in SCs, and thematically synthesizes the findings. The six theoretical perspectives and key themes that emerged from the literature were used to develop future research directions (RDs) for MS.

Findings

This study develops a multitheoretical framework and research agenda comprising 20 theory-driven RDs for MS, focusing on the environmental, firm and transaction levels.

Research limitations/implications

This study provides a reference for future MS research. Although the study used only six theories, future studies can develop further research agendas for MS based on diverse theories.

Practical implications

Practitioners can use this framework to understand MS from varied perspectives and identify and mitigate MS risks in SCs.

Originality/value

To the best of the author’s knowledge, this study presents the first comprehensive and theoretically grounded research agenda that positions MS research onto a stronger theoretical foundation.

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Article
Publication date: 19 December 2023

Muhammad Naveed Khan, Piyya Muhammad Rafi-ul-Shan, Pervaiz Akhtar, Zaheer Khan and Saqib Shamim

Achieving social sustainability has become a critical challenge in global supply chain networks, particularly during complex crises such as terrorism. The purpose of this study is…

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Abstract

Purpose

Achieving social sustainability has become a critical challenge in global supply chain networks, particularly during complex crises such as terrorism. The purpose of this study is to explore how institutional forces influence the social sustainability approaches of logistics service providers (LSPs) in high terrorism-affected regions (HTAR). This then leads to investigating how the key factors interact with Institutional Theory.

Design/methodology/approach

An exploratory multiple-case study research method was used to investigate six cases of different-sized logistics LSPs, each in an HTAR. The data was collected using semistructured interviews and triangulated using on-site observations and document analysis. Thematic analysis was used in iterative cycles for cross-case comparisons and pattern matching.

Findings

The findings interact with Institutional Theory and the three final-order themes. First, management processes are driven by coopetition and innovation. Second, organizational resources, structure and culture lead to an ineffective organizational design. Finally, a lack of institutionalization creates institutional uncertainty. These factors are rooted in many other first-order factors such as information sharing, communication, relationship management, capacity development, new process developments, workforce characteristics, technology, microlevel culture and control aspects.

Originality/value

This study answers the call for social sustainability research and enriches the literature on social sustainability, Institutional Theory and LSPs in HTARs by providing illustrations showing that institutional forces act as driving forces for social sustainability initiatives by shaping the current management processes. Conversely, the same forces impede social sustainability initiatives by shaping the current organizational designs and increasing institutional uncertainty.

Details

Corporate Governance: The International Journal of Business in Society, vol. 24 no. 3
Type: Research Article
ISSN: 1472-0701

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Article
Publication date: 6 June 2024

Kenyth Alves de Freitas, Barbara Bechler Flynn and Ely Laureano Paiva

This paper explores how a firm that is established in an environment characterized by uncertainty can engage with weak regulative institutions by developing operational and…

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Abstract

Purpose

This paper explores how a firm that is established in an environment characterized by uncertainty can engage with weak regulative institutions by developing operational and institutional capabilities.

Design/methodology/approach

We employ a multiple case study approach with seven leading multinational firms in Brazil in industries that vary in industry concentration.

Findings

Firms choose among alternative strategies for engaging with regulative institutions as an ongoing process, based on their assessment of four characteristics of the uncertainty they face and their capabilities. Strategies that require a firm to exert greater effort to adapt to institutions or influence institutions have a greater potential to catalyze for developing operational capabilities. Although firms in industries with different concentrations behave similarly in individually adapting to regulative institutions, firms in decentralized industries are more likely to collaborate to influence institutions, which enables them to both access public agents through network partners and better negotiate their own interests.

Practical implications

This research guides managers in developing institutional engagement strategies to reduce the potential consequences of institutional uncertainty in their supply chain. It also suggests types of institutional capability aligned with decentralized vs concentrated industries.

Originality/value

We extend the construct of institutional engagement strategies from the context of entrance to a new international market to an ongoing process in firms that are established in an environment characterized by weak regulative institutions. We also examine the role of industry concentration in the application of institutional engagement strategies.

Details

International Journal of Operations & Production Management, vol. 45 no. 2
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 4 February 2022

Enrico Fontana, Muhammad Atif and Mark Heuer

This article encourages novel approaches in the SSCM literature to create transformative change for workers in developing countries' apparel supply chains. It examines how…

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Abstract

Purpose

This article encourages novel approaches in the SSCM literature to create transformative change for workers in developing countries' apparel supply chains. It examines how suppliers' implementation of social sustainability is moderated by buyers' pressures (through dyadic ties) and by similar suppliers' pressures (through extended ties).

Design/methodology/approach

The article adopts a qualitative method design based on fieldwork and 21 face-to-face interviews with suppliers' senior managers. The data were collected between 2017 and 2020 in the factory premises of suppliers in Pakistan.

Findings

This article distinguishes the pressures that moderate suppliers' implementation of social sustainability positively (top-down encouragement, informal exchange and competitive convergence) and negatively (unrewarded commitment) through social ties. Hence, it shows how suppliers experience constrained proactivity as a state of tension.

Originality/value

The article primarily contributes to the SSCM literature by informing how similar suppliers' pressures in the business community constitute important processes of social governance and are key to create transformative change upstream in apparel supply chains. Against this backdrop, it cautions about buyers' opposite pressures and misuse of their negotiation power, which indirectly holds back and dilutes transformative change.

Details

International Journal of Physical Distribution & Logistics Management, vol. 53 no. 1
Type: Research Article
ISSN: 0960-0035

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Article
Publication date: 9 April 2019

Venkateswara Babu P., Ismail Syed and Satish Ben Beera

In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine…

321

Abstract

Purpose

In an internal combustion engine, piston ring-cylinder liner tribo pair is one among the most critical rubbing pairs. Most of the energy produced by an internal combustion engine is dissipated as frictional losses of which major portion is contributed by the piston ring-cylinder liner tribo pair. Hence, proper design of tribological parameters of piston ring-cylinder liner pair is essential and can effectively reduce the friction and wear, thereby improving the tribological performance of the engine. This paper aims to use surface texturing, an effective and feasible method, to improve the tribological performance of piston ring-cylinder liner tribo pair.

Design/methodology/approach

In this paper, influence of positive texturing (protruding) on friction reduction and wear resistance of piston ring surfaces was studied. The square-shaped positive textures were fabricated on piston ring surface by chemical etching method, and the experiments were conducted with textured piston ring surfaces against un-textured cylinder liner surface on pin-on-disc apparatus by continuous supply of lubricant at the inlet of contact zone. The parameters varied in this study are area density and normal load at a constant sliding speed. A comparison was made between the tribological properties of textured and un-textured piston ring surfaces.

Findings

From the experimental results, the tribological performance of the textured piston ring-cylinder liner tribo pair was significantly improved over a un-textured tribo pair. A maximum friction reduction of 67.6 per cent and wear resistance of 81.6 per cent were observed with textured ring surfaces as compared to un-textured ring surfaces.

Originality/value

This experimental study is helpful for better understanding of the potency of positive texturing on friction reduction and wear resistance of piston ring-cylinder liner tribo pair under lubricated sliding conditions.

Details

Industrial Lubrication and Tribology, vol. 71 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 October 2005

S.P.J. von Wielligh

Audits of long‐term insurers are complex, high‐risk engagements. The auditor’s consideration of materiality has a direct impact on the quality of such audits. So far, however, no…

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Abstract

Audits of long‐term insurers are complex, high‐risk engagements. The auditor’s consideration of materiality has a direct impact on the quality of such audits. So far, however, no research has been published on the application of materiality in audits of long‐term insurers. This study examines various aspects of planning materiality in the audits of listed South African long‐term insurers on the basis of responses to a questionnaire, taking into account issues identified from the literature reviewed. A number of recommendations are made on the basis of the findings. Largely on the basis of the results of this study, the South African Institute of Chartered Accountants has commissioned a project to revise existing guidance for auditors.

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Article
Publication date: 1 January 2006

Xiujie Jiang, Huixian Sun, Xiaomin Chen, Zhihua Wang, Li Zhang and Daxing Wang

This paper presents a new multi‐channel temperature measurement system (MCTMS) with small size, light weight and low power consumption for the microgravity fluid experiment of…

368

Abstract

Purpose

This paper presents a new multi‐channel temperature measurement system (MCTMS) with small size, light weight and low power consumption for the microgravity fluid experiment of drop Marangoni migration on SZ‐4 spaceship, a test module of the manned space mission of China.

Design/methodology/approach

The MCTMS, with a commercial‐off‐the‐shelf (COTS) component monolithic thermocouple amplifier with cold junction compensation AD595, is designed to measure temperature gradient field of up to 6 type T thermocouples Cu‐Constantan for microgravity fluid experiment. Through an analog multiplexer, the very small signal amplitude of the six‐channel temperatures can be acquired and amplified by the same monolithic thermocouple amplifier to retain the consistency of the six channels. A fully mission analysis and evaluation on the COTS component was taken into account before it was used in the thermal and radiation environment of space.

Findings

Using the COTS component in space can increase the system performance and considerably reduce the size, weight, power consumption and the overall complexity of the system. The measurement resolution of the MCTMS reaches 0.1°C because of the utilization of the COTS with high performance. In addition, the transfer function of the AD595 was deduced for type T thermocouples.

Originality/value

This paper suggests an easy way of measuring temperature for microgravity fluid experiment on spacecraft. Using a COTS component on spacecraft, also, is a new practical case study, which is more suitable for on‐board implementation. The MCTMS, presented in this work, has run in‐orbit successfully on SZ‐4 spaceship and the experiment result in space is reported.

Details

Aircraft Engineering and Aerospace Technology, vol. 78 no. 1
Type: Research Article
ISSN: 0002-2667

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