Condensation and Evaporation of Mutually Repelling Particles :Steady states and limit cycles

We study condensation and evaporation of particles which repel each other, using a simple set of rules on a square lattice. Different results are obtained for a mobile and an immobile surface layer.A two point limit cycle is observed for high temperature and low pressure in both cases. Here the coverage oscillates between a high and a low value without ever reaching a steady state. The results for the immobile case depend in addition on the initial coverage.Comment: 8 pages, 3 figure

Toward healthier, sustainable, medium density housing, through a return to natural materials

Medium density housing can be built sustainably using natural materials. These homes are healthy to live in and have minimal impact on the environment. Increasing demand, diminishing available land, climate change and unsustainable building practices all contribute to a growing housing crisis. The list of manufactured materials such as asbestos, PVC and formaldehyde, that are hazardous to us and our planet continues to grow. Many modern homes are not fit for purpose, being poorly insulated, damp mould inducing toxic buildings, recognised as a major contributor to poor health, and being detrimental in their manufacture to the environment. Until recently, natural building materials, perceived as inferior to modern manufactured products, have been considered unsuitable for modern building. The RADIUS¹ solution cycle is developed from this research as an organised design led process. Research driven by design, then through Analysis and Discussion, Inform Design, so as to Utilise new findings to Solve the conundrum. Historically, natural material structures last for hundreds and in some cases thousands of years. Just as ancient history can show us the way with materials, perhaps recent history can suggest answers to better medium density design, the hexagon is trialed here as one possible alternative site configuration. Global interest in natural materials in developed countries is growing, the higher labour cost is no longer considered problematic, being offset by the significant material cost and environmental impact savings, health benefits and an estimated building life expectancy exceeding 200 years. New Zealand as an advocate of healthy living and conservation of nature should lead the world by example in this field in which it is currently under-represented. A composite wall and floor of straw, clay, aggregate, sand and lime is readily available, renewable, sustainable and works synergistically to maintain correct moisture levels and inhibit mould. I present two housing developments as proof of concept that natural building materials offer new typologies and a healthy sustainabale way forward

Does the well-being of individuals with Down syndrome and dementia improve when using life story books and rummage boxes? A randomised single case series experiment

Background: This study investigated whether a personalised life story book and rummage box enhanced well-being and led to changes in behaviour for people with Down syndrome (DS) who have dementia. Materials & Methods: A randomised single-case series design was used with five participants who had Down syndrome and a diagnosis of dementia. Participants were invited to take part in three conditions at random a) life story book, b) rummage box and c) no intervention condition. Results: The two reminiscence conditions were significantly associated with enhanced well-being as compared to the no-intervention condition. However, for one participant, the life story book was associated with significantly higher well-being, while for another participant, the rummage box was associated with significantly higher well-being, suggesting some participants may prefer one method over another. Conclusions: Personalised life story books and rummage boxes are associated with higher levels of well-being for people with DS and dementia

Carbon steel wettability characteristics enhancement for improved enamelling using a 1.2 kW high power diode laser

High-power diode laser (HPDL) surface treatment of a common engineering carbon steel(EN8) was found to effect significant changes to the wettability characteristics of the metal. These modifications have been investigated in terms of the changes in the surface roughness of the steel, the presence of any surface melting, the polar component of the steel surface energy and the relative surface oxygen content of the steel. The morphological and wetting characteristics of the mild steel and the enamel were determined using optical microscopy, scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray (EDX) analysis and wetting experiments by the sessile drop technique. This work has shown that HPDL radiation can be used to alter the wetting characteristics of carbon steel so as to facilitate improved enamelling

High power diode laser modification of the wettability characteristics of an Al2O3/SiO2 based oxide compound for improved enamelling

High power diode laser (HPDL) surface melting of a thin layer of an amalgamated Al2O3/SiO2 oxide compound (AOC) resulted in significant changes in the wettability characteristics of the material. This behaviour was identified as being primarily due to: (i) the polar component of the AOC surface energy increasing after laser melting from 2.0 to 16.2 mJm-2, (ii) the surface roughness of the AOC decreasing from an Ra value of 25.9 to 6.3 μm after laser melting and (iii) the relative surface oxygen content of the AOC increasing by 36% after laser melting. HPDL melting was consequently identified as affecting a decrease in the enamel contact angle from 1180 prior to laser melting to 330 after laser melting; thus allowing the vitreous enamel to wet the AOC surface. The effective melt depth for such modifications was measured as being from 50 to 125 μm. The morphological, microstructural and wetting characteristics of the AOC were determined using optical microscopy, scanning electron microscopy, energy disperse X-ray analysis, X-ray diffraction techniques and wetting experiments by the sessile drop technique. The work has shown that laser radiation can be used to alter the wetting characteristics of the AOC only when surface melting occurs

The influence of a high power diode laser (HPDL) generated glaze on the wetting characteristics and the subsequent HPDL enamelling of ordinary Portland cement

High power diode laser (HPDL) surface glazing of the ordinary Portland cement (OPC) surface of concrete was found to effect significant changes in the wettability characteristics of the OPC. This behaviour was identified as being primarily due to: (i) the polar component of the OPC surface energy increasing after HPDL glazing from 3.46 to 15.56 mJm-2, (ii) the surface roughness of the OPC decreasing from an Ra value of 21.91 to 2.88 m after HPDL glazing and (iii) the relative surface O2 content of the OPC increasing by 4.5at% after HPDL glazing. HPDL glazing was consequently identified as occasioning a decrease in the enamel contact angle from an initial value of 1090 to 310, thus allowing the vitreous enamel to wet the OPC surface

On the role of laser-induced microstructures in influencing the surface energy of magnesia partially stabilized zirconia bioceramic

Surface energy must in some way be connected to surface chemistry and is therefore an important determinant of a biomaterial’s functions. This work elucidates the basic phenomena and wetting mechanisms associated for a widely used bioinert ceramic, magnesia partially stabilized zirconia (MgO-PSZ) following CO2 laser treatment. Contact angles for a set of test liquids were used to measure the wettability characteristics and to reduce the surface energy of the MgO-PSZ before and after CO2 laser treatment. CO2 laser treatment of the MgO-PSZ surface was seen to effect an improvement in the material’s wettability characteristics. Furthermore, it was found that the extent of wettability modi®cation was closely related to the microstructure induced by CO2 laser radiation on the surface of the MgO-PSZ

Improvement and decline of cognitive function in schizophrenia over one year: a longitudinal investigation using latent growth modelling.

BACKGROUND: Long-term follow-up studies of people with schizophrenia report stability of cognitive performance; less is known about any shorter-term changes in cognitive function. METHODS: This longitudinal study aimed to establish whether there was stability, improvement or decline in memory and executive functions over four assessments undertaken prospectively in one year. Cognitive performance was assessed during randomized controlled trials of first- and second-generation antipsychotic medication. Analyses used a latent growth modeling approach, so that individuals who missed some testing occasions could be included and trajectories of cognitive change explored despite missing data. RESULTS: Over the year there was significant decline in spatial recognition but no change in pattern recognition or motor speed. Improvement was seen in planning and spatial working memory tasks; this may reflect improved strategy use with practice. There were significant individual differences in the initial level of performance on all tasks but not in rate of change; the latter may have been due to sample size limitations. Age, sex, premorbid IQ and drug class allocation explained significant variation in level of performance but could not predict change. Patients randomized to first-generation drugs improved more quickly than other groups on the planning task. CONCLUSION: We conclude that cognitive change is present in schizophrenia but the magnitude of change is small when compared with the large differences in cognitive function that exist between patients. Analyses that retain patients who drop out of longitudinal studies, as well as those who complete testing protocols, are important to our understanding of cognition in schizophrenia.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Penetrating keratoplasty versus deep anterior lamellar keratoplasty for treating keratoconus

This is the protocol for a review and there is no abstract. The objectives are as follows: To compare visual outcomes after penetrating keratoplasty and DALK for keratoconus and identify the factors contributing to poor outcomes.National Health and Medical Research Council, Australia

The Adsorption of H2O on TiO2 and SnO2(110) Studied by First-Principles Calculations

First-principles calculations based on density functional theory and the pseudopotential method have been used to investigate the energetics of H$_2$O adsorption on the (110) surface of TiO$_2$ and SnO$_2$. Full relaxation of all atomic positions is performed on slab systems with periodic boundary conditions, and the cases of full and half coverage are studied. Both molecular and dissociative (H$_2$O $\rightarrow$ OH$^-$ + H$^+$) adsorption are treated, and allowance is made for relaxation of the adsorbed species to unsymmetrical configurations. It is found that for both TiO$_2$ and SnO$_2$ an unsymmetrical dissociated configuration is the most stable. The symmetrical molecularly adsorbed configuration is unstable with respect to lowering of symmetry, and is separated from the fully dissociated configuration by at most a very small energy barrier. The calculated dissociative adsorption energies for TiO$_2$ and SnO$_2$ are in reasonable agreement with the results of thermal desorption experiments. Calculated total and local electronic densities of states for dissociatively and molecularly adsorbed configurations are presented and their relation with experimental UPS spectra is discussed