On anomalous depth-dependency of the hardness of NiTi shape memory alloys in spherical nanoindentation

An experimental study on the indentation hardness of NiTi shape memory alloys (SMAs) by using a spherical indenter tip and a finite element investigation to understand the experimental results are presented in this paper. It is shown that the spherical indentation hardness of NiTi SMAs increases with the indentation depth. The finding is contrary to the recent study on the hardness of NiTi SMAs using a sharp Berkovich indenter tip, where the interfacial energy plays a dominant role at small indentation depths. Our numerical investigation indicates that the influence of the interfacial energy is not significant on the spherical indentation hardness of SMAs. Furthermore, the depth dependency of SMA hardness under a spherical indenter is explained by the elastic spherical contact theory incorporating the deformation effect of phase transformation of SMAs. Hertz theory for purely elastic contact shows that the spherical hardness increases with the square root of the indentation depth. The phase transformation beneath the spherical tip weakens the depth effect of a purely elastic spherical hardness. This study enriches our knowledge on the basic concept of hardness for SMAs under spherical indentation at micro- and nanoscales.

Explicit invariant solutions associated with nonlinear atmospheric flows in a thin rotating spherical shell with and without west-to-east jets perturbations

A class of non-stationary exact solutions of two-dimensional nonlinear Navier–Stokes (NS) equations within a thin rotating spherical shell were found as invariant and approximately invariant solutions. The model is used to describe a simple zonally averaged atmospheric circulation caused by the difference in temperature between the equator and the poles. Coriolis effects are generated by pseudoforces, which support the stable west-to-east flows providing the achievable meteorological flows. The model is superimposed by a stationary latitude dependent flow. Under the assumption of no friction, the perturbed model describes zonal west-to-east flows in the upper atmosphere between the Ferrel and Polar cells. In terms of nonlinear modeling for the NS equations, two small parameters are chosen for the viscosity and the rate of the earth’s rotation and exact solutions in terms of elementary functions are found using approximate symmetry analysis. It is shown that approximately invariant solutions are also valid in the absence of the flow perturbation to a zonally averaged mean flow.

Aqua optica - planet x

Planet X is video work which is presented using an original optical projection system which involves a large spherical lens, water and rear projection and various other materials including glass, timber, fabricated steel, etc and which I have called "Aqua Optica". The Planet X is 10 min looping video explores both the historical origins of the discovery of Pluto in 1930 (by astronomer Clyde Tombaugh at the Lowell Observatory) and the recent explorations of Pluto by NASA with the New Horizons space craft which was transmitting new images of Pluto at the time of this exhibition.

The telescopic eye: aqua optica

The Telescopic Eye: Aqua Optica was an installation work which explores concepts and philosophies related to instrumental, lens based observations of heavens as experienced when seeing through a telescope. In particular it considers how the eye of the observer and the lens of the telescope must act in unison to extend both the perception and conception of that which is remote and beyond direct naked eye sensing - an act of transcendence. A series of projected images (the video) of celestial objects are observed by the viewer through a large spherical aquatic lens which is mounted on a large wooden tripod. These images slowly dissolve and morph into each other. The sequence in which these images are presented is based on approximate chronological order in which these celestial objects were historically observed through the telescope – such as the local bodies of our the solar system starting with the Moon, Jupiter and Saturn (as first observed by Galileo in 1610) and eventually extending out to distant nebula, star clusters and galaxies. For the Transduction exhibition the Telescopic Eye: Aqua Optica was installed outside in a small quadrangle next to the Tech Bar and as the night drew darker it was able to also embody the lighting and other visual elements from the surrounding buildings and streets. The Aqua Optica system often encompasses such local lighting and images as a added layer to the video projection work. In this case (at night and outside at Federation Square) the extent of the layering was very successful and increased dramatically as the night became darker. This multi layering of images invokes (for the viewer) a connection between the immediate environment of the Federation square and cityscape with the vastly distant images of the cosmos. For me such a multilayered imaging represents how scientific instruments of observation can generate a complex and augmented visualisation of reality, one which has historically come to re-define our conception of the cosmos and our place in it both spatially and temporally.

Citing the saucers: astronomy, UFOs and a persistence of vision

This paper consists of two parallel and interweaving investigations regarding the UFO phenomenon and its origins with respect to observational astronomy. First, as a young child, I was fascinated with astronomy and would spend many hours with my toy telescope, viewing blurred images of the night sky. I also held a deep belief in UFOs and was committed to seeing and recording a flying saucer for myself. This led me to fabricate my own UFO photographs and from these I developed a critical relationship with photography as a means of documentation and as a medium of illusionary projection. This paper is therefore partly personal and reflexive.The second thread investigates the advent of the UFO phenomenon as a consequence of nineteenth and early twentieth century developments in observational astronomy, and the speculative theories regarding life on Mars that emerged during this period. I will be considering the work of Giovanni Schiaparelli, Percival Lowell and the writings of Carl Jung. I will be arguing that the primary force that led towards a belief in flying saucers emerged from the speculations and misinterpretations of certain astronomical observations, together with a desire to project upon that which was observed, rather than to see that which was there.