School of Physics - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 10
-
ItemNo Preview AvailableSpeckle and Conservation(International Seminars, 2008)The aim of this research is to demonstrate the usefulness of speckle, a trait of an expanded laser beam, for the non-destructive testing of artwork in both the imaging of subsurface structure and the quantitative detection of physical movement of canvas. Laser Speckle Contrast Method (LSCI) is a useful method for the viewing of subsurface layers and movement. By investigating the statistical properties of dynamic speckle it is possible to reveal drawings that are hidden beneath scattering layers such as the primary layer of paint or adhered paper. This is achieved by taking a series of speckle images captured in a short time frame and applying one of a number of post processing algorithms. We explore the limitations of this method when applied to various paper samples that have a sketch executed in various media beneath the top layer. The ability to resolve gray scale images was examined as well as looking at the dependence of the contrast of the revealed drawings to the temperature of the surface. Current work is being done on using LSCI to reveal indentations in artwork caused by the application process. The successful use of Electronic Speckle Pattern Interferometry (ESPI) both in the laboratory and in-situ for the detection of in-plane movement of painted canvas due to humidity fluctuations and the out-of-plane movement of paint as it dries has also been demonstrated. Canvas paintings can be very susceptible to movement due to changes of the environment. ESPI is a non-destructive technique yielding sensitive results that can detect displacement on a surface of less than the wavelength of the illuminating coherent light source. While ESPI has been successfully applied to the in-situ study of painted frescoes, previous studies have employed tensile testers as a support for painted canvas. We have shown a portable version of ESPI to be of use in tropical environment in the Philippines, Malaysia and Singapore with original artworks where variations in humidity occur and the samples have not undergone special preparation before analysis, revealing significant directional movements. Furthermore, a simple variation in the direction of beams paths permits the characterisation of out-of-plane movement, specifically as the height of paint shrinks due to the drying process. We have used ESPI to view the drying process of alkyd resin paints over the time period of 24 hours.
-
ItemImaging the Sunyaev Zel'dovich Effect using ACBAR on Viper(Cambridge University Press, 2004)During 2001 and 2002, observations of several X-ray bright clusters of galaxies were conducted using the ACBAR Bolometer Array on the South Pole Viper telescope. A multi-frequency analysis of these clusters is currently underway. This multi-frequency analysis includes 150, 220 and 275 GHz data from ACBAR, X-ray imaging and spectroscopy from Chandra and XMM-Newton, and weak lensing data from the CTIO 4m Blanco telescope. We describe here how ACBAR can be used to create fully sampled cluster images and present such images for four of the clusters in our sample; Abell 3266, Abell 3827, Abell S1063 and 1E0657-56. In these images, the Sunyaev-Zel'dovich Effect is clearly detected.
-
ItemA preliminary understanding of oil paintings in tropical Southeast Asia(Allied Publishers Pvt. Ltd., 2008)
-
ItemStress and aging effects on the transformation characteristics in Au-Cd alloys(TRANS TECH PUBLICATIONS LTD, 2000)The effect of martensite agin in a Au-49.5%Cd single crystal has been studied using a pushrod dilatometer with various applied stresses. The reverse transformation temperatures remain constant with aging time, temperature and applied stresses (0 - 0.04 MPa). A critical aging time of approximately 2-3 hours was found to exist for an alloy of this composition and appears to be dependent on the aging temperature.
-
ItemNo Preview AvailableChaotic transport in semiconductor, optical, and cold-atom systems(PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE, 2007)
-
ItemCoherence properties of light propagated through a scattering medium( 2004)Partially-coherent, quasi-monochromatic optical fields are fully described by their Mutual Optical Intensity (MOI) or the phase-space equivalent, the Generalised Radiance (GR). This paper reports on the application of a propagation-based phase-space tomographic technique for determining both the MOI and the GR of wavefields. This method is applied to the reconstruction of the MOI and the GR of an optical wavefield propagated through a suspension of ~10 μm diameter polystyrene spheres.
-
ItemA numerical optimal control approach to the design of an optical fibre-based evanescent field sensor(Elsevier BV, 2005-01-01)
-
ItemMotion Workshop: tracking motion in an on-line environment(Apple University Consortium Academic and Developers Conference, 2001)
-
ItemAUTC Physics Project: Learning outcomes and curriculum development(Uniserve Science, 2004)
-
ItemNo Preview AvailableInstabilities leading to vortex lattice formation in rotating bose-einstein condensates(The Australian Institute of Physics, 2006)