Diagnostics of rolling element bearings for the traction system of high speed trains : experimental evidences

Monitoring of the integrity of rolling element bearings in the traction system of high speed trains is a fundamental operation in order to avoid catastrophic failures and to implement effective condition-based maintenance strategies. Diagnostics of rolling element bearings is usually based on vibration signal analysis by means of suitable signal processing techniques. The experimental validation of such techniques has been traditionally performed by means of laboratory tests on artificially damaged bearings, while their actual effectiveness in industrial applications, particularly in the field of rail transport, remains scarcely investigated. This paper will address the diagnostics of bearings taken from the service after a long term operation on a high speed train. These worn bearings have been installed on a test-rig, consisting of a complete full-scale traction system of a high speed train, able to reproduce the effects of wheel-track interaction and bogie-wheelset dynamics. The results of the experimental campaign show that suitable signal processing techniques are able to diagnose bearing failures even in this harsh and noisy application. Moreover, the most suitable location of the sensors on the traction system is also proposed.

Experimental evidences in bearing diagnostics for traction system of high speed trains

Rolling element bearings are the most critical components in the traction system of high speed trains. Monitoring their integrity is a fundamental operation in order to avoid catastrophic failures and to implement effective condition based maintenance strategies. Generally, diagnostics of rolling element bearings is usually performed by analyzing vibration signals measured by accelerometers placed in the proximity of the bearing under investigation. Several papers have been published on this subject in the last two decades, mainly devoted to the development and assessment of signal processing techniques for diagnostics. The experimental validation of such techniques has been traditionally performed by means of laboratory tests on artificially damaged bearings, while their actual effectiveness in specific industrial applications, particularly in rail industry, remains scarcely investigated. This paper is aimed at filling this knowledge gap, by addressing the diagnostics of bearings taken from the service after a long term operation on the traction system of a high speed train. Moreover, in order to test the effectiveness of the diagnostic procedures in the environmental conditions peculiar to the rail application, a specific test-rig has been built, consisting of a complete full-scale train traction system, able to reproduce the effects of wheeltrack interaction and bogie-wheelset dynamics. The results of the experimental campaign show that suitable signal processing techniques are able to diagnose bearing failures even in this harsh and noisy application. Moreover, the most suitable location of the sensors on the traction system is proposed, in order to limit their number.

How does the use of a reflective journal enhance students’ critical thinking about complexity?

Introduction to Youth Services is a second year Social Work and Human Services unit. In this unit a reflective writing task was introduced to assess students’ reflections on an ongoing tutorial discussion to which they contributed. The discussion was based on a fictional young person each tutorial group ‘worked with’ across eight weeks of a semester. In developing the process and the criteria for the reflective journal, the ideas raised by the Teaching and Assessing Reflective Learning (TARL) in Higher Education project (see Chap. 2) were utilised, scaffolding the work with resources and submission of a draft. The students were also invited to choose the form of reflective process they used, it could be a written journal but did not need to be. The evidence exemplified that a reflective journal is an effective tool for students to record their developing understanding regarding the concept that issues people experience are complex and compounding. Importantly, it was also a useful vehicle for students to begin to consider the impacts of their own and others’ values and beliefs on their response to the issues raised within the case discussion. The reflective journal also helped participants to consider how this learning contributes to the ongoing development of their professional practice framework.

The history, content and evolution of The International Journal of the First Year in Higher Education

The International Journal of the First Year in Higher Education (Int J FYHE) began in 2010 with a specific FYHE focus and has published two issues per year with one issue linked to The International First Year in Higher Education Conference (FYHE Conference). This issue—Volume 6, Issue 1—is the last under this title. In 2015 the Journal will align to a new conference that has a broader focus on Students, Transitions, Achievement, Retention and Success (STARS). At this significant point and before we move on to the new journal, the journal team felt it was appropriate that the Feature in this final issue of the Int J FYHE should summarise the Journal’s activity over the years from 2010 to 2014.

Outdated journal rankings and the ERA exercise

As the results of the latest Excellence in Research Australia (ERA) exercise come closer to being announced, universities around Australia are holding their collective breaths. The ERA claims to be an assessment of research strengths and quality at Australian universities. While it is not supposed to produce a set of league tables, ultimately that is what tends to happen...

Journal of Education and Work: Special Issue: Creative Graduate Pathways Within and Beyond the Creative Industries

This special issue explores the nuances of graduate creative work, the kinds of value that creative graduates add through work of various types, graduate employability issues for creative graduates, emerging and developing creative career identities and the implications for educators who are tasked with developing a capable creative workforce. Extant literature tends to characterise creative careers as either ‘precarious’ and insecure, or as the engine room of the creative economy. However, in actuality, the creative workforce is far more heterogeneous than either of these positions suggest, and creative careers are far more complex and diverse than previously thought. The task of creative educators is also much more challenging than previously supposed.

Sustainable construction trends in journal papers

Sustainable construction is gaining worldwide attention and has inspired research to identify and solve the problems involved in its implementation over a project lifecycle. While an impressive number of papers have been published on the topic to date, little has been done to review these papers to identify current research status or provide guidance for future research. This paper reviews existing sustainability papers in 12 internationally renowned construction journals. Based on a three-stage literature review, sustainability papers published in these journals from 2000 to 2012 are analyzed in terms of the annual number of papers published and the research interests involved. The number of sustainability-related papers in construction increases from 30 papers in 2000 to 127 papers in 2012, which shows an increasing trend in sustainability topics. A content analysis identifies seven major research interest in sustainability, including: (1) sustainable project management; (2) sustainability assessment/evaluation; (3) sustainable technology/innovation implementation; (4) sustainable building/infrastructure performance; (5) government policy on sustainability; (6) enterprise sustainability, and; (7) sustainability education. The results of this study provide a reference for scholars and academics to understand the current status of sustainability research in major construction journals.

Editorial for Journal of Learning Design, 6(3) - "Special issue: Legal education and curriculum renewal"

Welcome to this special edition of the Journal of Learning Design which focuses on legal education and curriculum renewal in law. At the outset ,we would like to thank the editors of the Journal, Margaret Lloyd and Nan Bahr for agreeing to host this special edition. The special edition is timely as legal education in Australia is enjoying a lively period of renewal.

Fluidity of mica particle dispersed aluminium alloy

Cast aluminium alloy-mica particle composites were made by dispersing mica particles in a vortex produced by stirring the liquid Al-4 wt% Cu-1.5 wt% Mg alloy and then casting the melt containing the suspended particles into permanent moulds. Spiral fluidity and casting fluidity of the alloy containing mica particles in suspension were determined. Both the spiral fluidity and the casting fluidity of the base alloy were found to decrease with an increase in volume or weight percent of mica particles (of a given size), and with a decrease in particle size (for a given amount of particles). The fluidities of Al-4 wt% Cu-1.5 wt% Mg alloys containing suspended mica particles were found to correlate very well with the surface area of suspended mica particles. The regression equation for spiral fluidity Y (cm) as a function of surface area of mica particles per gram of spiral X (cm2 g–1) at 700° C was found to be Y=42.62–0.42X with a correlation coefficient of 0.9634. The regression equations for casting fluidity Yprime (cm) as a functiono of surface area of mica particles per gram of fluidity test piece Xprime (cm2 g–1) at 710 and 670° C were found to be Yprime=19.71–0.17Xprime and Yprime=13.52–0.105Xprime with correlation coefficients of 0.9194 and 0.9612 respectively. The percentage decrease in casting fluidity of composite melts containing up to 2.5 wt% mica with a drop in temperature is quite similar to the corresponding decrease in the casting fluidity of base alloy melts (without mica). The change in fluidity due to mica dispersions has been discussed in terms of changes in viscosity of the composite melts. However, the fluidities of these composite alloys containing up to 2.5 wt% mica are adequate for making a variety of simple castings including bearings for which these alloys have been developed.

International Journal of Music Business Research. Special Issue on the Australasian Music Economy

The music business is one of the most international of all the cultural industries. Music, industry practices, and people travel easily across country borders and the major music companies are dominating national music markets across the globe. However, at the same time the music industries in different countries are very idiosyncratic. Music is an ingrained part of a country’s history, its culture and heritage. One aspect of this idiosyncrasy is related to how creatives, audiences and music organizations are affected by and is able to take advantage of the ongoing digitization of society.

Preparation of cast aluminium alloy-mica particle composites

The optimum conditions for producing cast aluminium alloy-mica particle composites, by stirring mica particles (40 to 120 mgrm) in molten aluminium alloys (above their liquidus temperatures), followed by casting in permanent moulds, are described. Addition of magnesium either as pieces along with mica particles on the surface of the melts or as a previously added alloying element was found to be necessary to disperse appreciable quantities (1.5 to 2 wt.%) of mica particles in the melts and retain them as uniform dispersions in castings under the conditions of present investigation. These castings can be remelted and degassed with nitrogen at least once with the retention of about 80% mica particles in the castings. Electron probe micro-analysis of these cast composites showed that magnesium added to the surface of the melt along with mica has a tendency to segregate around the mica particles, apparently improving the dispersability for mica particles in liquid aluminium alloys. The mechanical properties of the aluminium alloy-mica particle composite decrease with an increase in mica content, however, even at 2.2% the composite has a tensile strength of 14.22 kg mm–2 with 1.1% elongation, a compression strength of 42.61 kg mm–2, and an impact strength of 0.30 kgm cm–2. The properties are adequate for certain bearing applications, and the aluminium-mica composite bearings were found to run under boundary lubrication, semi-dry and dry friction conditions whereas the matrix alloy (without mica) bearings seized or showed stick slip under the same conditions.

Mechanical testing of internal fixation devices: A theoretical and practical examination of current methods

Successful healing of long bone fractures is dependent on the mechanical environment created within the fracture, which in turn is dependent on the fixation strategy. Recent literature reports have suggested that locked plating devices are too stiff to reliably promote healing. However, in vitro testing of these devices has been inconsistent in both method of constraint and reported outcomes, making comparisons between studies and the assessment of construct stiffness problematic. Each of the methods previously used in the literature were assessed for their effect on the bending of the sample and concordant stiffness. The choice of outcome measures used in in vitro fracture studies was also assessed. Mechanical testing was conducted on seven hole locked plated constructs in each method for comparison. Based on the assessment of each method the use of spherical bearings, ball joints or similar is suggested at both ends of the sample. The use of near and far cortex movement was found to be more comprehensive and more accurate than traditional centrally calculated inter fragmentary movement values; stiffness was found to be highly susceptible to the accuracy of deformation measurements and constraint method, and should only be used as a within study comparison method. The reported stiffness values of locked plate constructs from in vitro mechanical testing is highly susceptible to testing constraints and output measures, with many standard techniques overestimating the stiffness of the construct. This raises the need for further investigation into the actual mechanical behaviour within the fracture gap of these devices.