The calculation of noise from railway bridges and viaducts

Pandrol Rail Fastenings Limited are a designer and manufacturer of railway rail-fastening systems. As an organisation they have the capability to reduce the noise impact of bridges using resilient track components. They also have a commercial interest in providing such technology. Knowledge of the processes behind bridge noise is important to Pandrol in two ways; to aid the engineers within the organisation in the design of fastening systems and to demonstrate a state-of-the-art understanding of the problem of railway bridge noise to customers, as this will aid in the sale of Pandrol products. The fitting of new rail components to an existing track form, or failure to meet noise regulations with a new track form, can be costly. It is important to be able to predict accurately the effectiveness of noise reduction techniques. Currently, Pandrol’s knowledge of the problem consists almost entirely of experience gained and data gathered while working on existing bridge projects. To expand their knowledge base, Pandrol perform noise and vibration measurements on railway bridges and viaducts and then use the measured data to predict the performance of their systems on other bridges. This completely empirical approach to predicting bridge noise is both costly and situation specific results cannot be provided before the installation of the fastening system. Another approach to predicting bridge noise is through the application of analytical models. Limited analytical modelling in the context of bridge noise is currently conducted within the organisation. For these reasons, Pandrol are sponsoring research into bridge noise in the form of this EngD project. Here an existing rapid calculation approach is identified that relies less on the exact geometry of the bridge and more on its general characteristics. In this approach an analytical model of the track is coupled to a statistical energy analysis (SEA) model of the bridge. This approach forms a suitable basis from which to develop a better model here by concentrating on its weaknesses. A mid-frequency calculation for the power input to the bridge via a resilient track system has been developed by modelling the track-bridge system as two finite Timoshenko beams continuously connected by a resilient layer. This has resulted in a power input calculation which includes the important effects of coupling between the rail and bridge and the resonance effects of the finite length of a bridge. In addition, a detailed study of the frequency characteristics of deep I-section beams has been performed using Finite Element, Boundary Element and Dynamic stiffness models. It is shown that, at high frequencies, the behaviour of the beam is characterised by in-plane motion of the beam web and bending motion in the flange. This knowledge has resulted in an improved calculation for the mobility of a bridge at high frequencies. The above improvements are included in an improved model for use by Pandrol in their general activities. Data from real bridges is compared to predictions from the improved model in order to validate different aspects of the model. The model is then used to study the effect on noise of varying many bridge design parameters. It is shown that the parameter that has most influence on the noise performance of a bridge is the dynamic stiffness of the resilient rail fastening system. Additionally it is demonstrated that for a given bridge and noise receiver location, an optimum fastener stiffness exists where the noise radiated by the bridge and track is at a minimum

Transnational labor regulation, reification and commodification: A critical review

Why does scholarship on transnational labor regulation (TLR) consistently fails to search for improvements in working conditions, and instead devotes itself to relentless efforts for identifying administrative processes, semantics, and amalgamations of stakeholders? This article critiques TLR from a pro-worker perspective, through the philosophical work of Georg Lukács, and the concepts of reification and commodification. A set of theoretically grounded criteria is developed and these are applied against selected contemporary cases of TLR. In the totality that is capitalism, reification of social relations of production conceals completely the experiences of workers. In TLR, managerialist and process-oriented scholarship is dominant, verifiable outcomes and positive improvements in conditions of employment are not sought, and worse, meaningless procedures are celebrated as positive achievements

Georg Lukács as a Communications Scholar: Cultural and Digital Labour in the Context of Lukács’ Ontology of Social Being

The task of this work is to apply thoughts from Georg Lukács’ final book, the Ontology of Social Being, for the theoretical analysis of cultural and digital labour. It discusses Lukács’ concepts of work and communication and relates them to the analysis of cultural and digital work. It also analyses his conception of the relation of labour and ideology and points out how we can make use of it for critically understanding social media ideologies. Lukács opposes the dualist separation of the realms of work and ideas. He introduces in this context the notion of teleological positing that allows us to better understand cultural and digital labour as well as associated ideologies, such as the engaging/connecting/sharing-ideology, today. The analysis shows that Lukács’ Ontology is in the age of Facebook, YouTube, and Twitter still a very relevant book, although it has thus far not received the attention that it deserves. This article also introduces the Ontology’s main ideas on work and culture, which is important because large parts of the book have not been translated from the German original into English. Lukács’ notion of teleological positing is crucial for understanding the common features of the economy and culture

A preliminary study on how accuracy relates to student self reports of confidence on a conceptual physics test

We report on a study involving three streams of first year physics students at the University of Sydney – Fundamentals, Regular and Advanced. Students from the three streams completed a multiple choice conceptual quiz on the web as part of their first assignment. They also indicated how confident they were that their answer(s) were correct. As expected the mean values of accuracy and confidence vary according to streams, and prior exposure and achievement in physics. In this context, we explore the viability of the meta-cognitive constructs of ‘calibration’ and ‘bias’

We belong together: Reflections on a Virtual Introduction to Professional Learning

Poste

Automated Counting of Bacterial Colony Forming Units on Agar Plates

Manual counting of bacterial colony forming units (CFUs) on agar plates is laborious and error-prone. We therefore implemented a colony counting system with a novel segmentation algorithm to discriminate bacterial colonies from blood and other agar plates

Assessing dose rate distributions in VMAT plans

Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within ±0.4 s and doses ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min(-1) for conventional fractionation. A tool to analyze dose rate distributions in VMAT plans with sub-second accuracy was successfully developed and validated. Dose rates encountered in clinical VMAT test cases show a continuous spectrum with a mean less than or near 100 cGy min(-1) for conventional fractionation

Paisaje y sociedad de alta montaña en <em>De Madrid a Nápoles</em> (1861) de Pedro Antonio de Alarcón

The passage from <em>De Madrid a Nápoles</em> (1861) in which Pedro Antonio de Alarcón describes the alpine landscape is a relevant document, as it contains the first detailed depiction of Mont Blanc’s range that we come across in the history of Spanish travel literature. In the text, Alarcón sets an archaic lifestyle ideal against material progress linked to the birth of the modern metropolis under industrial revolution. This outlook anticipates the strong conservative attitude towards social changes that will increasingly be adopted by the Spanish writer in the last years of his life. From this alpine description emerge distinctive romantic clichés associated with an aesthetic dear to Alarcón that unexpectedly blend with a religious vision of nature. Furthermore, we analize the role of Bædeker’s travel guide book on Switzerland (whose 4^th edition, published in 1859, is well known to Alarcón) and the traces it has left in this extensive passage.<br><br>El extenso pasaje en el que Pedro Antonio de Alarcón describe, en <em>De Madrid a Nápoles</em> (1861), el territorio alpino es un valioso texto documental ya que constituye la primera descripción pormenorizada de la cadena del Mont Blanc que se registra en la tradición española de la literatura de viajes. Advertimos el propósito de contraponer un ideal de vida arcaico a la fe en el progreso material que anima a la metrópoli nacida a remolque de la revolución industrial, lo que presagia el conservadurismo ideológico de Alarcón. La descripción pone de manifiesto viejos clichés románticos, a cuya estética permanece Alarcón en parte apegado, y que se alían de manera inesperada con una visión espiritualizada de la naturaleza. Se sopesa además la huella que la guía turística Bædeker sobre Suiza, cuya 4.ª edición (1859) el autor lleva consigo en su viaje, deja en el fragmento descriptivo alpino

Fusion Learning Conference 2021 - Supplement

This is a supplement to the proceedings of the 2021 Fusion Learning Conference held at Bournemouth University in the UK and contains material not previously published