Large deviation analysis of a simple information engine

Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine which can be seen as a modern version of `Maxwell's Daemon', whereby the feedback controller is acting as a Daemon, processing information gained about the system in order to do work. Here, we analyse a simple model of such an engine and provide a detailed analysis of its fluctuation properties, including the large deviations of information. We find an exact expression of the large deviation rate function for a two-site version of our model, and provide an approximate analysis for larger systems which is corroborated by simulation data.Comment: 12 pages, 13 figure

Students with disability : data collection for reporting in New Zealand universities : a thesis presented in partial fulfillment of the requirements for the degree of Master of Philosophy in Rehabilitation at Massey University, Palmerston North, New Zealand

The Ministry of Education in New Zealand has dedicated funding to increase the participation of people with disability in tertiary education. However there has been no standardised system in place for defining disability, categorising impairment, or collecting, maintaining and reporting data about tertiary students with disability, in order to determine the eventual impact of this initiative. The present study utilised a cross-sectional survey in a single stage sampling procedure, to gather information from the eight New Zealand universities regarding definitions of disability and categories of impairment used to collect data, as well as the source of data collection and numerical characteristics of the population. Data collected showed a steady increase in the population of university students with disability from 3,039 in 1998 to 4,358 in 2000. However the findings were consistent with the evidence in the literature review that it is currently not possible to know the real number of these students because of the differences in data collection and reporting across institutions. These findings indicated that data was not sourced in the same way across institutions. Furthermore, information was kept in segregated databases in some institutions, which did not all have a means of exchanging data with their general student record system. The Ministry of Education's reporting template introduced in 2001 was found to provide only a partially standardised framework for reporting on data. There must also be a systematic method of collecting and maintaining data across tertiary institutions, including clarification of the sets of students to be counted, so that all institutions are counting students in the same way. The present study identified confusion in language and definitions, with the terms impairment, disability, illness and injury being used interchangeably. The International Classification of Functioning, Disability and Health was suggested as providing a practical functional model for data collection, which could be used as a platform for establishing definitions and clarifying the language around disability and impairment, as well as providing an international standard for establishing consistency

Mode-switching: a new technique for electronically varying the agglomeration position in an acoustic particle manipulator

Acoustic radiation forces offer a means of manipulating particles within a fluid. Much interest in recent years has focussed on the use of radiation forces in microfluidic (or “lab on a chip”) devices. Such devices are well matched to the use of ultrasonic standing waves in which the resonant dimensions of the chamber are smaller than the ultrasonic wavelength in use. However, such devices have typically been limited to moving particles to one or two predetermined planes, whose positions are determined by acoustic pressure nodes/anti-nodes set up in the ultrasonic standing wave. In most cases devices have been designed to move particles to either the centre or (more recently) the side of a flow channel using ultrasonic frequencies that produce a half or quarter wavelength over the channel, respectively.It is demonstrated here that by rapidly switching back and forth between half and quarter wavelength frequencies – mode-switching – a new agglomeration position is established that permits beads to be brought to any arbitrary point between the half and quarter-wave nodes. This new agglomeration position is effectively a position of stable equilibrium. This has many potential applications, particularly in cell sorting and manipulation. It should also enable precise control of agglomeration position to be maintained regardless of manufacturing tolerances, temperature variations, fluid medium characteristics and particle concentration