For over 120 years, the shell middens of western Scotland and the series of open-air sites on Oronsay have been the focus of debate in European Mesolithic studies. This paper challenges the significance of Oronsay in light of results from the geophysical survey and test-excavation of a new limpet and periwinkle shell midden dated to the late 5th or start of the 4th millennium cal bc at Port Lobh, Colonsay that offers fresh evidence to re-evaluate critically the role of Oronsay and coastal resources in island settlement models ahead of the Mesolithic–Neolithic transition. Test excavations recovered a marine molluscan assemblage dominated by limpet and periwinkle shells together with crab, sea urchin, a fishbone assemblage composed mainly of Gadidae, some identifiable bird and mammal bone, carbonised macroplant remains, and pumice as well as a bipolar lithic assemblage and coarse stone implements. Novel seasonality studies of saithe otolith thin-sections suggest wintertime tidal fishing practices. At least two activity events may be discerned, dating from the late 5th millennium cal bc. The midden could represent a small number of rapidly deposited assemblages or maybe the result of stocastic events within a more extended timeframe. We argue that alternative research questions are needed to advance long-standing debates about seasonal inter-island mobility versus island sedentism that look beyond Oronsay to better understand later Mesolithic occupation patterns and the formation and date of Oronsay middens. We propose alternative methodological strategies to aid identification of contemporaneous sites using geophysical techniques and lithic technological signatures.

Many ancient Chinese bronze mirrors have survived with their original surface decorationsintact, particularly those with “glassy” black surface coatings. The microstructures and compositions of cross-sectional samples from ancient mirrors have been analyzed with optical and electron microscopy and synchrotron x-ray fluorescence. The core has a two-phase metal structure while the surface shows evidence of selective dissolution of copper from the α (Curich) phase. The ci phase regions are replaced pseudomorphically by a mineral product with the δ (Sn-rich) phase remaining metallic. A fundamental study of the electrochemistry of the copper-tin system has given information on theconditions under which selective dissolution of copper takes place. Electrochemical polarization has been used to drive the copper dealloying process in cast high-tin bronze. Theresulting microstructure is similar to the dealloyed microstructure observed in the ancient samples.

Thin film layers of shape memory alloys and ferroelectric ceramics can produce a family of ‘smart’ heterostructures capable of performing both sensing and actuating functions. Important issues in the synthesis of these active structures are the ability to generate the appropriate crystalline phases of each material, while producing defect-free homogeneous high quality films. The compatibility of sol-gel processed Pb(Zr,Ti)O3 (PZT) thin films with thin film shape memory effect TiNi substrates were investigated. Thin film TiNi was deposited on quartz substrates by physical sputter deposition utilizing a TiNi target in a ultra-high vacuum chamber, and followed by in-situ vacuum annealing. PZT was deposited on TiNi by sol-gel and spin coating processes. The ferroelectric tetragonal phase of PZT was obtained by a 600 °C anneal for 5m in air. The heterostructures were nominally defect-free, unlike those obtained through deposition onto bulk TiNi substrates.x

The shape memory alloy TiNi is produced by either Vacuum Induction Melting (VIM) or by Vacuum Arc Remelting (VAR) of pure metal ingots for actuator applications. Powder metallurgy techniques provide an alternative fabrication route for their use in passive damping applications where porosity and deviations in chemical homogeneity can be tolerated. In this study TiNi compacts were cold pressed from the blended elemental powders and sintered in vacuum for varying times at temperatures from 800°C to 1000°C. Two heating rates were used, 5 K/min. and 10 K/min. A TiNi microstructure could be produced after annealing at 1000°C for 6 h., although some TiNi3 was still observed. Sintering above 900°C produced porous microstructures with green densities approaching 3.5 gm/cm3.

Synthesis of Pb(Ti,Zr)O3 (PZT) coatings onto glass microspheres was demonstrated using solgel techniques. Characterization of the coatings was performed using XRD and SEM to demonstrate that piezoelectric PZT coating are possible. This study represents an initial feasibility study into the manufacture of so-called “smart” material fabrication utilizing different geometries.

Thin film layers of shape memory alloys and ferroelectric ceramics can produce a family of ‘smart’ heterostructures capable of performing both sensing and actuating functions. The compatibility of sol-gel processed BaTiO3 (BTO) and SrTiO3 (STO) thin films with shape memory effect TiNi substrates were investigated. Important issues in the synthesis of these active structures are the ability to generate the appropriate crystalline phases of each material while producing defect-free homogeneous high quality films.

The minimum temperature for the crystallization of amorphous TiNi on substrates is of interest in developing thin-film SME material while minimizing chemical interactions with the substrate. Using 20 micron thick free standing TiNi material annealed in a vacuum furnace, X-Ray diffraction of the thin-films indicated that the crystallization occured within 20 minutes at 510°C, 490°C and 480°C. At 450°C, crystallization kinetics were significantly slower, and the foils were fulling crystallized after annealing for 7.5 hrs. To further lower the crystallization temperature, cold working of the foil by rolling was introduced and full crystallization was observed after 7.5 hours annealing at 400°C in a cold-worked foil. Cold working and annealing at 400°C and 350°C for 7.5 hrs did not observably promote lower crystallization temperatures.

Although the thermo-mechanical properties of NiTi are well known for bulk material, its deposition and utilization as a thin film are still in their earliest stages of research. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparatively large transformation forces. This has made it a promising candidate material as micro-actuators for Micro-Electro-Mechanical (MEMS) systems as well as for strain measurements. The cycling time for actuation was measured for a 20 μm free standing NiTi thin film cantilever. It was demonstrated that cycling frequencies of up to 50 Hz are achievable.

Active and adaptive thin film materials for “smart” materials will likely be a heterostructure of several types of thin films. In this investigation, deposition and processing of thin film Shape Memory Effect TiNi and thin film ferroelectric BaTiO3 and SrTiO3 are discussed. Growth conditions as well as the thermodynamic conditions for thin films are described. It was found that amorphous thin films of TiNi and BaTiO3 can be crystallized simultaneously by air annealing at 600°C.

Recent studies by this author and others has demonstrated that cavitation-erosion of NiTi coatings or bulk NiTi is exceptional. Studies were undertaken to ascertain whether this property is a consequence of either the general intermetallic properties of NiTi or by an adaptive stress-dissipation mechanism of the cavitation-generated shock wave by A microstructural mechanism related to the shape memory effect.

In cavitation, an oscillating pressure field causes the formation and implosion of air bubbles. As a surface easily nucleates bubbles, the subsequent implosion of the bubbles generates stresses approaching several MPa, which are large enough to ablate material, and are also high enough to generate stress-induced Martensite or Austenite, depending on whether the applied stress is tensile or compressive. The implication is that the stress wave may be partially accommodated by the stress-induced transformation, which can dissipate the energy as heat on retransformation to the materials unstressed phase.

Calculations concerning the variation of the cavitation-induced stresses and temperature distribution with depth into the TiNi coupled with the associated problems of heat transfer will be presented. It will be shown that an adaptive mechanism is plausible.

The thermo-mechanical properties of NiTi are well known for bulk material although its deposition and utilization as a thin film are still in their earliest stages. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparitively large transformation forces, and so is a promising candidate as a micro-actuator for MicroElectroMechanical (MEMS) systems as well as in strain measurements. The response time for a variety of NiTi layers were modelled under different boundary conditions and show response times similar to the acoustic velocities for one micron thick NiTi.

The rate of decay of a macroscopic sinusoidal grating etched into a clean surface can be predicted from its surface and volume diffusion coefficients and the partial pressure of the material. The microscopic theory of crystal growth and evaporation of Hirth and Pound has produced an expression for the step velocity for a surface in equilibrium with its own vapor, which was used to simulate the decay of a sinusoidal surface. The macroscopic decay rate was determined from the measured surface diffusion coefficient and the equilibrium vapor pressure of the Ni (100) surface. The rate of decay of a model sinusoidal grating surface using the microscopic step velocities was inconsistent with the observable mnacroscopic results. Reasons for this are discussed.

Thermal spray technologies provide a method for depositing high temperature intermetallics. Deposits of Shape Memory Effect NiTi were produced by Electric-Arc Spraying (EAS) of NiTi wire, Vacuum Plasma Spraying (VPS) of NiTi powder, and codeposition of Ni and Ti using VPS. NiTi deposits displayed shape memory effect properties, which are highly sensitive to processing conditions. They were found to also exhibit superior cavitation-erosion resistance. Under identical cavitation erosion conditions, weight losses of 0.41, 1.65 amd 7.71 mg were found VPS, arc-sprayed and blended Ni-Ti deposits respectively. Minimal amounts of NiTi was formed from co-spraying both Ni and Ti powders onto steel substrates.

Thin-films of Ni and Ti were formed by sputter co-deposition of Ni and Ti onto amorphous SiO2 and single crystal NaCl and Sapphire substrates. Films were characterized as follows: a) The chemical composition of the films was analysed by EDAX b) The gross morphology was examined by Scanning Electron Microscopy. c) The crystal phases were indentified by X-ray diffraction and Electron diffraction. Intermetallic NiTi has been identified in samples annealed in vacuo at 850°C. Annealing at 500°C in vacuum produced chemical separation of the Ni and Ti. This effect may be due to a narrow solidus region for the existence of NiTi and inhomogeneities due to uneven deposition of the Ni and Ti.