Numerical Study on the Recoating Process in Microstereolithography

Microstereolithography is a promising RP-based micro-fabrication technique that aims to meet the demands for complex geometry micro-scale parts. Projection microstereolithography incorporates a Dynamic Pattern Generator to obtain high resolution in the parallel plane. However, its lateral resolution has been always limited by the final layer thickness and the long resin settling time, both of which rely on the recoating process. In order to find the critical factors behind the recoating process, a numerical simulation method (Computational Fluid Dynamics, CFD) has been used to investigate the relationships among final layer thickness, settling time, resin viscosity and ratio of object/container size. These results are helpful for the selection of resin characteristics and the design of the microstereolithography machine.Mechanical Engineerin

Balloon-borne ultraviolet stellar spectrometer: Acquisition, tracking and command systems

The NASA Balloon-borne Ultraviolet Stellar Spectrometer (BUSS) which is carried to an altitude of 40 km by a 15 million cubic foot balloon for night-time observations of ultraviolet stellar spectra is discussed. The BUSS optical system, comprising an 0.40 m aperture Cassegrain telescope and an Ebert-Fastie spectrometer, points at various selected stars and focuses a portion of their spectra on the photocathode of an image dissector tube. The spectral region between 2,775 Angstroms and 2,825 Angstroms is sampled by the detector at 0.25 Angstroms increments using photon counting techniques. The pointing system for the payload uses a pair of orthogonal magnetometers which sense the earth's magnetic field for an aximuth reference, and a platform potentiometer for an elevation reference. This pointing system places the target star within the 3x1 degree field of view of an outer optical star tracker. The outer star tracker is then used to point the entire instrument to within one arc minute of the target star

The family and the church in the eighteenth and nineteenth centuries

The published articles and papers that form this submission focus on the nature of English Society between 1689 and 1900. In particular they address the nature of the family and the Church as social institutions. The underlying theme of the three groups of publications is the strength of continuity in these institutions. 1. THE EARLY MODERN FAMILY. This group of publications considers the nature of the family between the Restoration and the Edwardian eras. The function of the family, and the desire to make provision for its survival was an important feature, reflected in the practise of nepotism among the middle class professional families that dominated the clergy. Dynastic survival was also important, perhaps even socially imperative, for families from the upper echelons of society. As a result these landed families frequently resorted to social and legal fictions to suggest the continuity and legitimacy of their dynasties. Against the background of the vicissitudes that affected the Wane family, these fictions often assured survival. 2. THE EIGHTEENTH CENTURY CHURCH. This group of publications demonstrates that the Church in the eighteenth century was not the moribund and corrupt institution it has been held to be by Victorian historians. It was, rather, a vibrant and dynamic institution, whose bishops and clergy were painstaking, committed and achieved a significant level of professional success. Where reform and change was necessary, there is evidence that eighteenth century bishops undertook it; often reversing the neglect of the preceding century. The system of patronage, often the subject of attack, contained more integrity than is often allowed, and even solicitous clergy are not easily censured. 3. THE NINETEENTH CENTURY CHURCH. This group of publications advances the view that the sharp delineation of the eighteenth and nineteenth centuries into two `eras' of ecclesiastical history is untenable. The reforms of the eighteenth century were extended into the realm of patronage by the Governments of 1812-30; the re-introduction of rural deans started in the 1820s and the career and educational patterns within the episcopate evolved only slowly. Thus rather than the Whig reforms of the 1830s acting as a historical watershed, they were another feature in a series of evolutionary reforms. Equally, features of the Church in the eighteenth century persisted late into the nineteenth century: the exercise of personal patronage by prime ministers, motivated by a range of secular factors, and the career and educational pattern of the episcopate are examples of this persistence. These three themes confirm a number of associated historical trends. There is no doubt that they lend weight to the importance of the hereditary element among the professional classes. They also confirm the view that English society was one in which social mobility was present, particularly within the Church. Though it would be rash to suggest the eighteenth and nineteenth centuries saw the rise of a meritocracy, it may however be reasonable to suggest that the rise and reward of merit in the eighteenth century was more prevalent than has hitherto been suggested

Contour surveying system Patent

Describing device for surveying contour of surface using X-Y plotter and traveling transduce

Creating the Technopolis: High-Technology Development in Austin, Texas

New institutional alliances, driven by the rapid increase in and diversity of new technologies, are altering the strategy and tactics of economic development. As a result, communities across the world are seeking to create modern technopoleis or city-states that interactively link technology commercialization with public and private sectors to spur economic growth and diversification through high-technology company development. This paper develops the conceptual framework of a technopolis wheel from studying the dynamics of high-technology development and economic growth in Austin, Texas. It describes seven segments within the technopolis: the university, large technology companies, small technology companies, federal government, state government, local government and support groups. (Author's preprint.)IC2 Institut

Parameter identification for a robotic manipulator arm

The development is described of a nonlinear dynamic model for large oscillations of a robotic manipulator arm about a single joint. Optimization routines are formulated and implemented for the identification of electrical and physical parameters from dynamic data taken from an industrial robot arm. Special attention is given to the role of sensitivity in the formulation of robust models of this motion. The importance of actuator effects in the reduction of sensitivity is established and used to develop an electromechanical model of the manipulator system

Parameter identification and sensitivity analysis for a robotic manipulator arm

The development of a nonlinear dynamic model for large oscillations of a robotic manipulator arm about a single joint is described. Optimization routines are formulated and implemented for the identification of electrical and physical parameters from dynamic data taken from an industrial robot arm. Special attention is given to difficulties caused by the large sensitivity of the model with respect to unknown parameters. Performance of the parameter identification algorithm is improved by choosing a control input that allows actuator emf to be included in an electro-mechanical model of the manipulator system

Free-flight measurements of dynamic stability derivatives of a blunted 120 deg cone in helium at Mach number 15.4

Free flight measurements of dynamic stability derivatives of blunted 120 deg cone in helium compared to unmodified Newtonian theory prediction

High-resolution N-body Simulations of Galactic Cannibalism: The Magellanic Stream

Hierarchical clustering represents the favoured paradigm for galaxy formation throughout the Universe; due to its proximity, the Magellanic system offers one of the few opportunities for astrophysicists to decompose the full six-dimensional phase-space history of a satellite in the midst of being cannibalised by its host galaxy. The availability of improved observational data for the Magellanic Stream and parallel advances in computational power has led us to revisit the canonical tidal model describing the disruption of the Small Magellanic Cloud and the consequent formation of the Stream. We suggest improvements to the tidal model in light of these recent advances.Comment: 6 pages, 4 figures, LaTeX (gcdv.sty). Refereed contribution to the 5th Galactic Chemodynamics conference held in Swinburne, July 2003. Accepted for publication in PASA. Version with high resolution figures available at http://astronomy.swin.edu.au/staff/tconnors/publications.htm