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Article
Publication date: 26 September 2008

Ramiro Martins and Jorge Seabra

This paper's aim is to present the gear micropitting performance of two industrial gear oils: a standard mineral lubricant (CM) containing a special micropitting additive…

Abstract

Purpose

This paper's aim is to present the gear micropitting performance of two industrial gear oils: a standard mineral lubricant (CM) containing a special micropitting additive package and a biodegradable ester with low toxicity additivation.

Design/methodology/approach

Gear micropitting tests were performed on the FZG machine, using type C gears made of case carburized steel. Lubricant samples were collected during the tests for analyzing the wear particles generated during operation. Post‐test analysis included the visual inspection of the teeth flanks and the assessment of the micropitting area, the mass loss of the gear, the ferrometric analysis of the lubricant samples and the surface roughness measurement of the teeth flanks, below and above the pitch line.

Findings

The micropitting performance of the two lubricants was very similar, confirming the advantage of using the ester lubricant (CE) as an industrial gear oil, now that it is an environmentally friendly product.

Research limitations/implications

The tests were only performed on carburizing steel and refer to the tested lubricants.

Practical implications

The study confirms the appropriateness of biodegradable ester oil to industrial gear applications, allowing the replacement of environmentally harmful gear lubricants. It shows that the micropitting protection conferred is similar to that exhibited by highly additivated CMs.

Originality/value

The paper shows the applicability of biodegradable CEs to gear lubrication, mainly where it concerns micropitting protection, and shows its potential advantages, together with the biodegradability.

Details

Industrial Lubrication and Tribology, vol. 60 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 8 February 2011

Ramiro Martins, Cristiano Locatelli and Jorge Seabra

The purpose of this paper is to get a better understanding of roughness evolution and micropitting initiation on the tooth flank, as well as the evolution of surface…

Abstract

Purpose

The purpose of this paper is to get a better understanding of roughness evolution and micropitting initiation on the tooth flank, as well as the evolution of surface topography during the test load stages in a modified DGMK short micropitting test procedure.

Design/methodology/approach

A modified DGMK short micropitting test procedure was performed, using an increased number of surface observations (three times more) in order to understand the evolution of the surface during each load stage performed. Each of these surface observations consists in the evaluation of surface roughness, surface topography, visual inspection and also weigh measurements as well as lubricant analysis.

Findings

This work showed that the larger modifications on surface took place in the beginning of tests, especially during load stage K3 (lowest load, considered as running‐in) and on the first period of load stage K6, that is, during the first 200,000 cycles of the test. The 3D roughness parameters (St and Sv), obtained from the surface topographies, gave a more precise indication about surface roughness evolution and micropitting generation than the 2D parameters, especially in what concerns to inferring the depth of micropits and the reduction of roughness. Tooth flank topography allows to identify local changes on the surface and the appearance of first micropits.

Research limitations/implications

This work was performed with gears holding a high surface roughness and with a ester‐based lubricant. It was interesting to see the differences observed for surface evolution, for other base oils and also for gears with lower roughness.

Practical implications

The main implication of this work is the understanding that major changes in the surface took place in the first cycles, indicating that the running‐in procedure could be very important for the surface fatigue life. This work also showed that micropitting depends on local contact conditions. Depending on the roughness of the counter surface, micropitting can appear on the bottom of the deep valleys and/or do not appear on the tip of the roughness peaks. The surface topography, and implicitly 3D roughness parameters, is very useful for the observation of surface evolution.

Originality/value

This paper shows in detail the evolution of the tooth surface during a micropitting test. The micropits generation and evolution and also surface wear evolution are presented.

Details

Industrial Lubrication and Tribology, vol. 63 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 8 February 2011

Luis Magalhaes, Ramiro Martins, Cristiano Locateli and Jorge Seabra

The purpose of this paper is to develop innovative geometry for gears aiming low power loss and easy manufacturing.

Abstract

Purpose

The purpose of this paper is to develop innovative geometry for gears aiming low power loss and easy manufacturing.

Design/methodology/approach

New gear profiles were developed and studied, and gears were built accordingly and then tested using an FZG machine.

Findings

Results from the experimental tests revealed the influence of the profile modifications on the operating temperature, thus on the efficiency of gears (in terms of power loss).

Research limitations/implications

Studied cases were limited to experimental gear models compliant to the FZG machine.

Practical implications

Low‐loss gears can be produced using common technologies and tools. Its design includes power loss minimization besides mechanical strength. The new gears are more environmentally friendly and can operate with lower power consumption, lower temperature, increasing gear and gear oil life.

Originality/value

This work contributes to the development of the “low‐loss gears” concept, adapting it to low‐cost manufacturing technologies. Finally, more efficient gears and gearboxes can be produced only by performing simple geometrical modifications to standard gears.

Details

Industrial Lubrication and Tribology, vol. 63 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 June 1999

Eileen Oliver

Cuba’s 1959 Revolution brought about dramatic changes not only in that island‐nation but also in the USA. Cubans, and later Cuban‐Americans, have changed the face of Miami…

Abstract

Cuba’s 1959 Revolution brought about dramatic changes not only in that island‐nation but also in the USA. Cubans, and later Cuban‐Americans, have changed the face of Miami and south Florida. The economic and social successes of Cuban‐Americans, the third largest Latino group in the USA, are prevalent in scholarly and popular literature. In this annotated bibliography, the author presents journal articles, chapters in books, books, and human rights reports, published between 1990 and 1998, as well as World Wide Web sites, that discuss the Cuban‐American experience. Articles from the popular literature are not included, nor are materials that deal primarily with Cuba or Cuba‐USA relations.

Details

Reference Services Review, vol. 27 no. 2
Type: Research Article
ISSN: 0090-7324

Keywords

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Book part
Publication date: 19 May 2009

Abstract

Details

Immigration, Crime and Justice
Type: Book
ISBN: 978-1-84855-438-2

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Abstract

Details

Experiencing Persian Heritage
Type: Book
ISBN: 978-1-78754-813-8

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Book part
Publication date: 13 November 2017

Nohora García

Abstract

Details

Understanding Mattessich and Ijiri: A Study of Accounting Thought
Type: Book
ISBN: 978-1-78714-841-3

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Book part
Publication date: 19 May 2009

William F. McDonald

The immigration, crime, and justice nexus holds a special place in the history of criminology. It is one of the oldest, longest running, and ideologically conflicted focal…

Abstract

The immigration, crime, and justice nexus holds a special place in the history of criminology. It is one of the oldest, longest running, and ideologically conflicted focal concerns in the discipline. Its lineage reflects the field's record of scholarly innovation in methodology and theory as well as the development of related subjects of special interest, such as victimology and its subfields, domestic violence, human trafficking, hate crime, victim–offender relationships, and other related topics such as community policing and transnational crime and justice.

Details

Immigration, Crime and Justice
Type: Book
ISBN: 978-1-84855-438-2

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Book part
Publication date: 6 September 2019

Abstract

Details

Experiencing Persian Heritage
Type: Book
ISBN: 978-1-78754-813-8

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Book part
Publication date: 13 March 2012

Francisco López Segrera

This chapter has three main objectives: (1) to address the qualitative and quantitative impact of globalization in higher education institutions (HEI) and in the higher…

Abstract

This chapter has three main objectives: (1) to address the qualitative and quantitative impact of globalization in higher education institutions (HEI) and in the higher education systems (HES) in different regions and countries during the past 20 years; (2) stress the need of having specific levels of social equity in order to attain a permanent education for all and for life applying adequate educational policies; and (3) refer briefly to the need of a world report on higher education.

The ideas discussed in this chapter highlight key issues identified by the United Nations Educational, Scientific and Cultural Organization (UNESCO) regarding higher education, such as access, diversification, pertinence (or social commitment), quality, management, financing, new technologies of information and communication (ICT), and international cooperation.

Details

As the World Turns: Implications of Global Shifts in Higher Education for Theory, Research and Practice
Type: Book
ISBN: 978-1-78052-641-6

Keywords

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