Remediation of mud pumping on a ballasted railway track

Maintenance of ballasted railway tracks is a major cost for railway infrastructure owners. In many developed countries, much of the railway infrastructure is mature and was built for service requirements long since superseded. The increased demands on historic infrastructure can lead to the development or exacerbation of localised trackbed problems that require disproportionate levels of maintenance. Identifying these and applying cost effective remediation has the potential to reduce maintenance spend in the long term. However, it is not always clear what the most cost effective remediation will be. One type of localised maintenance issue is the development of wet beds or wet spots, which can occur where saturated clayey subgrade soils are overloaded and result in the development of mud pumping as trains pass. This leads to the migration of fines into the ballast bed and a deterioration in local track performance. Over time the track overlying the wet bed settles disproportionately more, sleepers become progressively more voided, and train ride quality deteriorates. Maintenance of the wet bed may involve locally digging out and replacing the ballast; however, unless the underlying cause is addressed the problem is likely to recur, requiring repeated localised maintenance interventions. This is costly, reactive and ultimately an ineffective approach to managing the problem. This paper presents a study of a wet bed in the UK, both prior to and after a full track renewal. Transient track deflections during train passage were monitored using sleeper mounted geophones and high speed filming techniques. Loaded track geometry data were obtained from a track recording vehicle. It is shown that local maintenance interventions were generally ineffective, but that a renewal of the top 200 mm of the trackbed including placement of a geotextile filter and geogrid appears to have been successful in remediating the problem, at least in the short term

New Zealand Rugby Country: How the Game Shaped our Nation

Desmond Wood has produced a very readable social history of rugby union in New Zealand. The strength of the book lies in the way he synthesizes scholarly analyses of the game, including his own interviews and research, into an easily accessible style

Junction Integrity for Low Temperature Dopant Activation in Silicon

Detailed within this paper is investigation of using low temperature processes to activate dopant in silicon. Parameters studied include breakdown voltage, turn-on voltage, leakage current, and ideality factor. Strong correlation was seen between the temperature of activation and both the ideality factor and leakage current. Breakdown voltage seemed constant except for the highest temperature processing. Turn-on voltage seemed to change for boron activation, but not for phosphorus activatio

From Chronology to Confessional: New Zealand Sporting Biographies in Transition

Formerly rather uniform in pattern, sporting biographies have evolved significantly since the 1970s, becoming much more open in their criticism of teammates and administrators as well as being more revealing of their subject’s private lives. This article identifies three transitional phases in the genre; a chronological era, extending from the early twentieth century until the 1960s; an indirectly confessional phase between the 1970s and mid 1980s and an openly confessional phase from the mid-1980s. Despite these changes, sporting biographies continue to reinforce the dominant narratives around sport in New Zealand

From Chronology to Confessional: New Zealand Sporting Biographies in Transition

Formerly rather uniform in pattern, sporting biographies have evolved significantly since the 1970s, becoming much more open in their criticism of teammates and administrators as well as being more revealing of their subject’s private lives. This article identifies three transitional phases in the genre; a chronological era, extending from the early twentieth century until the 1960s; an indirectly confessional phase between the 1970s and mid 1980s and an openly confessional phase from the mid-1980s. Despite these changes, sporting biographies continue to reinforce the dominant narratives around sport in New Zealand

New Zealand Rugby Country: How the Game Shaped our Nation

Desmond Wood has produced a very readable social history of rugby union in New Zealand. The strength of the book lies in the way he synthesizes scholarly analyses of the game, including his own interviews and research, into an easily accessible style

Deriving Minimal Sensory Configurations for Evolved Cooperative Robot Teams

This paper presents a study on the impact of different robot sensory configurations (morphologies) in simulated robot teams that must accomplish a collective (cooperative) behavior task. The study’s objective was to investigate if effective collective behaviors could be efficiently evolved given minimal morphological complexity of individual robots in an homogenous team. A range of sensory configurations are tested in company with evolved controllers for a collective construction task. Results indicate that a minimal sensory configuration yields the highest task performance, and increasing the complexity of the sensory configuration does not yield an increased task performance

Evolving Robust Robot Team Morphologies for Collective Construction

This research falls within evolutionary robotics and the larger taxonomy of cooperative multi-robot systems. A study of comparative methods to adapt the behaviors and morphologies of simulated robot teams that must solve a collective construction task is presented. Multiple versions of an indirect encoding (developmental) method for the artificial evolution of team behaviors and morphologies were tested. Results indicated the developmental method was able to evolve effective robot team morphologies in a collective construction task, where evolved teams yielded a task performance comparable to optimal team morphologies manually designed specifically for the collective construction task. Results also indicated that the developmental method was appropriate for evolving controllers that were able to generalize to a range of different team morphologies that also solved the collective construction task with a high degree of task performance