The Effect of Coating Patterns with Spinel-Based Investment on the Castability and Porosity of Titanium Cast into Three Phosphate-Bonded Investments

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

IMPROVEMENT TO THE MARGINAL COPING FIT OF COMMERCIALLY PURE TITANIUM CAST IN PHOSPHATE-BONDED INVESTMENT BY USING A SIMPLE PATTERN COATING TECHNIQUE

Statement of problem. Coatings of zirconite, Y2O3 or ZrO2 on wax patterns before investing in phosphate-bonded investments have been recommended to reduce the reaction layer in titanium castings, but they are not easily obtainable. Spinel-based investments are relatively stable with molten titanium and could be used as coatings to improve the quality of castings made with those investments. Purpose. The purpose of this study was to evaluate the effect of pattern coating with a commercial spinel-based investment before investing in 1 of 3 phosphate-bonded investments on the marginal coping fit and surface roughness of commercially pure titanium castings. Material and methods. Ten square acrylic resin patterns (12 x 12 x 2 mm) per group were invested in the phosphate-bonded investments Rematitan Plus (RP), Rema Exakt (RE), and Castorit Super C (CA) with or without a coating of the spinel-based investment, Rematitan Ultra (RU). After casting, the specimens were cleaned and the surface roughness was measured with a profilometer. Copings for dental implants with conical abutment were invested, eliminated, and cast as previously described. The copings were cleaned and misfit was measured with a profile projector (n=10). For both tests, the difference between the mean value of RU only and each value of the phosphate-bonded investment was calculated, and the data were analyzed by 2-way ANOVA and Tukey's HSD test (alpha=.05). In addition, the investment roughness was measured in bar specimens (30 x 10 x 10 mm), and the data (n=10) were analyzed by 1-way ANOVA and Tukey's HSD post hoc test (alpha=.05). Results. Two-way ANOVA for casting surface roughness was significant because of the investment, the coating technique, and the interaction between variables. One-way ANOVA was performed to prove the interaction term, and Tukey's post hoc test showed that RP with coating had the lowest mean, while RP had the highest. CA with coating was not different from RP with coating or CA without coating. RE with coating was similar to CA, while RE was different from all groups. For coping marginal fit, the 2-way ANOVA was significant for the investment, the coating technique, and the interaction between variables. The interaction was analyzed by1-way ANOVA and Tukey's HSD test that showed no significant difference among the coated groups, which had better marginal fit than the groups without coating. Among the groups without coating, CA had significant lower marginal misfit than RP, while RE was not different from CA and RP. For the investment surface roughness, the 1-way ANOVA was significant. CA and RU were smoother than RE and RP (P<.001). Conclusions. The coating technique improved the quality of castings fabricated with phosphate-bonded investments. (J Prosthet Dent 2012;108:51-57)

Comparing "socially responsible" and "sustainable" commercial property investment

Purpose – The purpose of this paper is to set out to explore the similarities and differences between jargon used to describe future-focussed commercial building product. This is not so much an exercise in semantics as an attempt to demonstrate that responses to challenges facing the construction and property sectors may have more to do with language than is generally appreciated. Design/methodology/approach – This is a conceptual analysis which draws upon relevant literature. Findings – Social responsibility and sustainability are often held to be much the same thing, with each term presupposing the existence of the other. Clearly, however, there are incidences where sustainable commercial property investment (SCPI) may not be particularly socially responsible, despite being understood as an environmentally friendly initiative. By contrast, socially responsible assets, at least in theory, should always be more sustainable than mainstream non-ethically based investment. Put simply, the expression of social responsibility in the built environment may evoke, and thereby deliver, a more sustainable product, as defined by wider socially inclusive parameters. Practical implications – The findings show that promoting an ethic of social responsibility may well result in more SCPI. Thus, the further articulation and celebration of social responsibility concepts may well help to further advance a sustainable property investment agenda, which is arguably more concerned about demonstrability of efficiency than wider public good outcomes. Originality/value – The idea that jargon affects outcomes is not new. However, this idea has rarely, if ever, been applied to the distinctions between social responsibility and sustainability. Even a moderate re-emphasis on social responsibility in preference to sustainability may well provide significant future benefits with respect to the investment, building and refurbishment of commercial property.

Performance of magnesia cements in porous blocks in acid and magnesium environments

The performance of porous blocks containing three different reactive magnesia-based cements - namely magnesia alone, magnesium oxide: Portland cement (PC) in 1:1 ratio, cured in ambient conditions, and magnesia alone, cured at elevated carbon dioxide conditions, in hydrochloric acid and magnesium sulfate solution - was investigated. Different aggressive chemical solution conditions were used, to which the samples were exposed for up to 12 months and then tested for strength and microstructure. The performance was also compared with that of standard PC-based blocks. The results showed the significant resistance to chemical attack offered by magnesia, both alone and with PC blend in the porous blocks when cured under ambient carbon dioxide conditions, and confirmed the much poorer performance of blocks made from PC alone. The blocks of solely magnesia cured in elevated carbon dioxide conditions, at 20% concentration, showed slightly lower resistance to acid attack than PC; however, the resistance to sulfate attack was much higher. © 2012 Thomas Telford Ltd.

Three essays on the psychology of investment and financial markets

Préface My thesis consists of three essays where I consider equilibrium asset prices and investment strategies when the market is likely to experience crashes and possibly sharp windfalls. Although each part is written as an independent and self contained article, the papers share a common behavioral approach in representing investors preferences regarding to extremal returns. Investors utility is defined over their relative performance rather than over their final wealth position, a method first proposed by Markowitz (1952b) and by Kahneman and Tversky (1979), that I extend to incorporate preferences over extremal outcomes. With the failure of the traditional expected utility models in reproducing the observed stylized features of financial markets, the Prospect theory of Kahneman and Tversky (1979) offered the first significant alternative to the expected utility paradigm by considering that people focus on gains and losses rather than on final positions. Under this setting, Barberis, Huang, and Santos (2000) and McQueen and Vorkink (2004) were able to build a representative agent optimization model which solution reproduced some of the observed risk premium and excess volatility. The research in behavioral finance is relatively new and its potential still to explore. The three essays composing my thesis propose to use and extend this setting to study investors behavior and investment strategies in a market where crashes and sharp windfalls are likely to occur. In the first paper, the preferences of a representative agent, relative to time varying positive and negative extremal thresholds are modelled and estimated. A new utility function that conciliates between expected utility maximization and tail-related performance measures is proposed. The model estimation shows that the representative agent preferences reveals a significant level of crash aversion and lottery-pursuit. Assuming a single risky asset economy the proposed specification is able to reproduce some of the distributional features exhibited by financial return series. The second part proposes and illustrates a preference-based asset allocation model taking into account investors crash aversion. Using the skewed t distribution, optimal allocations are characterized as a resulting tradeoff between the distribution four moments. The specification highlights the preference for odd moments and the aversion for even moments. Qualitatively, optimal portfolios are analyzed in terms of firm characteristics and in a setting that reflects real-time asset allocation, a systematic over-performance is obtained compared to the aggregate stock market. Finally, in my third article, dynamic option-based investment strategies are derived and illustrated for investors presenting downside loss aversion. The problem is solved in closed form when the stock market exhibits stochastic volatility and jumps. The specification of downside loss averse utility functions allows corresponding terminal wealth profiles to be expressed as options on the stochastic discount factor contingent on the loss aversion level. Therefore dynamic strategies reduce to the replicating portfolio using exchange traded and well selected options, and the risky stock.

IMPROVEMENT TO THE MARGINAL COPING FIT of COMMERCIALLY PURE TITANIUM CAST IN PHOSPHATE-BONDED INVESTMENT BY USING A SIMPLE PATTERN COATING TECHNIQUE

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Quality Assessment of Titanium Castings Produced in an Experimental Short-Heating-Cycle Investment

The aim of this study was to evaluate the quality of casting produced in an experimental short-term heating-cycle investment. Thus, reaction layer and castability of titanium casting using an experimental spinel-based investment (VR) with short heating cycle were compared with the commercial short-heating-cycle spinel-based investment Trinell (TR), the silica-phosphate-based investment Rematitan Plus ( RP), and the conventional spinel-based investment Rematitan Ultra (RU). VR has polymeric fibers added to inorganic particles. Reaction layer assessments were carried out using Vickers hardness and elemental analysis using dispersive X-ray microanalysis (EDX). Mesh patterns were used for castability test, and powder characterization was made by scanning electron microscopy (SEM). Hardness evaluation showed no difference among the investments between 100 and 200 mu m. The most important contaminant element for VR, TR, and RU was oxygen. Higher levels of mold filling were found for TR, VR, and RU compared with that obtained with RP. The quality of castings, characterized by means of the assessments of reaction layer and castability, made from the VR was similar to the commercial investments TR and RU but superior to the RP.

Microstructural, physical, and fluid dynamic assessment of spinel-based and phosphate-bonded investments for dental applications

This work reports the experimental evaluation of physical and gas permeation parameters of four spinel-based investments developed with or without inclusion of sacrificial fillers. Data were compared with those of three commercial formulations. Airflow tests were conducted from 27 to 546°C, and permeability coefficients were fitted from Forchheimer's equation. Skeletal densities found for spinel- (ρs = 3635 ± 165 kg/m3) and phosphate-bonded (ρs = 2686 ± 11 kg/m3) samples were in agreement with the literature. The developed investments were more porous and less permeable than commercial brands, and the differences were ascribed to the different pore morphologies and hydraulic pore sizes of ceramic matrices. The inclusion of both fibers and microbeads resulted in increases of total porosity (42.6–56.6%) and of Darcian permeability coefficient k1 (0.76 × 10−14–7.03 × 10−14 m2). Air permeation was hindered by increasing flow temperatures, and the effect was related to the influence of gas viscosity on ΔP, in accordance with Darcy's law. Casting quality with molten titanium (CP Ti) was directly proportional to the permeability level of the spinel-based investments. However, the high reactivity of the silica-based investment RP and the formation of α-case during casting hindered the benefits of the highest permeability level of this commercial brand.

Designing REDD+ to be just : considerations for a legally binding instrument

The international climate regime is in the process of negotiating a legally binding instrument concerning Reducing Emissions from Deforestation and Degradation (REDD+). The paper starts by exploring the complex web of decisions and advices that currently regulate REDD+ initiatives within the international climate regime. This is followed by an analysis of justice issues raised by non-state actors in the REDD+ international negotiations. The paper concludes by building on this analysis to identify some relevant considerations when seeking to design a just and legally binding REDD+ instrument. These considerations include: the impact of market- versus fund-based investment channels, the importance of defining a clear objective; the inclusion and role of international principles such as sovereignty, preventative action, common but differentiated responsibility, sustainable development, and Free, Prior, and Informed Consent; the appropriate design of REDD+ safeguards and the inclusion of grievance mechanisms within the instrument which provide guidance on resolving disputes associated with REDD+ investment.

China’s National Security Review: a tit-for-tat response?

China is gradually taking its place as a major regulator, exercising concurrent jurisdiction of the national security review along with the US and EU over high-profile cross-border mergers and acquisitions. The National Security Review (NSR) regulatory regime of foreign acquisitions has attracted significant attention recently with the establishment of China's counterpart to the Committee on Foreign Investment in the United States (CFIUS). Due to the intensified activities of sovereign wealth funds (SWFs) that are closely linked with states, CFIUS's broad discretion to deal with China's SWF-based investment may have a far-reaching impact on China's implementation of the newly enacted NSR regime. It is essential to design a mechanism that allows SWFs to maximise their positive attributes while safeguarding the apolitical integrity of the marketplace. Any disproportionate use of the NSR regime would inevitably bring about more unintended consequences, such as tit-for-tat protectionism. This represents an imminent threat to the tenuous recovery from the recent economic crisis, largely because of the increasingly intertwined and interdependent nature of the global financial markets. It is of utmost significance to evaluate the extent to which the updated legislation strikes a reasonable balance between preserving genuine national security interests and maintaining an open environment for investment.

The valuation of self-funded retirement villages in Australia

Changing demographics will see an increasing demand for self-funded sector retirement villages in Australia. As such, valuers can expect to be more involved in providing valuation advice in this sector, although the central issue remains that retirement villages are complex businesses. They have been described as management intensive operating businesses with a substantial real estate element. As a result the valuation process in this sector requires a different type of analysis, in comparison to the traditional real estate based investment.
This paper provides an analysis of recent trends in the demand for retirement villages and examine current practise with respect to valuation thereof. It emphasises the need for a greater awareness of the ‘business enterprise value’ component and provides a framework within which the components of value can be better understood. The purpose of the paper is to provide a foundation for a greater reliability with respect to valuation advice.

THE INFLUENCE of SHORT-HEATING-CYCLE INVESTMENTS on THE QUALITY of COMMERCIALLY PURE TITANIUM CASTINGS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência da presença de um filme fino de platina na resistência de união titânio-cerâmica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de um revestimento com processamento rápido para fundição de titânio na camada de reação, porosidade interna, fluidez, rugosidade superficial e adaptação marginal de Copings

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)