Finite element analyses of repaired articular surfaces.

The response to a compressive load of a repaired cartilage surface, consisting of full-thickness repair tissue adjacent to normal cartilage, was predicted by the u-p finite element method and compared to that of a normal cartilage surface under the same loading conditions. By individually varying the aggregate modulus, permeability and Poisson's ratio for the repair tissue, analyses were performed to assess the contributions of each to the changes in mechanical behaviour. In comparing the repaired to normal surfaces, the presence of a softer repair tissue resulted in increased axial and decreased radial deformations at any given time point, while a repaired surface with an increased permeability compressed more easily due to the increased fluid flow and caused equilibrium to occur sooner. For smaller Poisson's ratio, the axial deformation was not different from normal if the aggregate modulus was the same as normal; however, the radial expansion was reduced as the repair tissue experienced a larger volume change. These results indicate that the presence of repair tissue in a joint surface can have a strong influence on the mechanical behaviour of the surface.     

Contributions of Transformation and Microcracking to the Plastic Deformation of Magnesia-Partially-Stabilized Zirconia

The measured plastic deformation of Mg-PSZ under stress contains contributions from both transformation and microcracking. A method is described to separate the contributions from transformation and microcracking for samples deformed in uniaxial tension. Such a separation enables the ratio of the longitudinal to transverse strains arising from the transformation to be estimated. The results are compared to the predictions of the shear–dilatation model of Chen and Reyes-Morel. Serious discrepancies are found between the experimental results and the predictions of the model and the possible reason for this is discussed.     

An adaptive analog continuous-time CMOS biquadratic filter

An adaptive analog continuous-time biquadratic filter is realized in a 2-μm digital CMOS process for operation at 300 kHz. The biquad implements the notch, bandpass and low-pass transfer functions. The only parameter adapted is the resonant frequency of the biquad, which is identical to the notch frequency and the bandpass center frequency. The update method is based on a least-means-square algorithm which adapts the notch frequency to minimize the power at the notch filter output. The actual update is modified to reduce the circuit complexity to one biquad and one correlator. When the filter is tracking a sinusoid, this update generates a ripple-free gradient that decreases tracking error. Applications include phase-frequency detectors, FM demodulators (linear and frequency shift keying), clock extractors, and frequency acquisition aids for phase-locked loops and Costas loops. Measured results from experimental prototypes are presented. Nonidealities of an all-analog implementation are discussed, along with suggestions to improve performance     

Can Robots Manifest Personality?: An Empirical Test of Personality Recognition,Social Responses,and Social Presence in Human–Robot Interaction

Personality is an essential feature for creating socially interactive robots. Studies on this dimension will facilitate enhanced human–robot interaction (HRI). Using AIBO, a social robotic pet developed by Sony, we examined the issue of personality in HRI. In this gender-balanced 2 (AIBO personality: introvert vs. extrovert) by 2 (participant personality: introvert vs. extrovert) between-subject experiment (N = 48), we found that participants could accurately recognize a robot's personality based on its verbal and nonverbal behaviors. In addition, various complementarity attraction effects were found in HRI. Participants enjoyed interacting with a robot more when the robot's personality was complementary to their own personalities than when the robot's personality was similar to their own personalities. The same complementarity attraction effect was found in participants' evaluation of the robot's intelligence and social attraction. Participants' feelings of social presence during the interaction were a significant mediator for the complementarity attraction effects observed. Practical and theoretical implications of the current study for the design of social robots and the study of HRI were discussed.     

Synthesis and Characterisation of Some New Ferrocenyl- and Ferrocenylalkynyl-[60]Fullerene Compounds

We report the synthesis and characterisation of a series of ferrocenylfullerene compounds, and some new ferrocene derivatives required as intermediates. The new fullerene species are Fc-[60]fullerene, (8); Fc-C=C-[60]fullerene, (10); Fc-C=C-C=C-[60]fullerene, (12); and (η-C₅H₄SiBu₃)Fe(η-C₅H₄)-[60]fullerene, (14).     

Information technology and regulatory reformThe interorganisational effects of a technological innovation

This paper examines whether information technology can play a strategic role in supporting regulatory reforms aimed at achieving voluntary cooperation with government regulation. Analysis of the case of electronic tax return lodgment in Australia suggests that the effects of IT are contextual, and identifies positive effects of the new IT system on voluntary cooperation. However, in this case, divergence between private and public interests and uncertainty and lack of participation in regulatory decision-making appear to restrict the development of voluntary cooperation as a primary basis for government regulation.     

Using argumentation to model agent decision making in economic experiments

In this paper we demonstrate how a qualitative framework for decision making can be used to model scenarios from experimental economic studies and we show how our approach explains the results that have been reported from such studies. Our framework is an argumentation-based one in which the social values promoted or demoted by alternative action options are explicitly represented. Our particular representation is used to model the Dictator Game and the Ultimatum Game, which are simple interactions in which it must be decided how a sum of money will be divided between the players in the games. Studies have been conducted into how humans act in such games and the results are not explained by a decision-model that assumes that the participants are purely self-interested utility-maximisers. Some studies further suggest that differences in choices made in different cultures may reflect their day to day behaviour, which can in turn be related to the values of the subjects, and how they order their values. In this paper we show how these interactions can be modelled in agent systems in a framework that makes explicit the reasons for the agents’ choices based upon their social values. Our framework is intended for use in situations where agents are required to be adaptable, for example, where agents may prefer different outcome states in transactions involving different types of counter-parties.     

Zeolite Formation in Class F Fly Ash Blended Cement Pastes

Zeolite formation in Class F fly ash blended cement pastes is under investigation. A Na–P type zeolite and Zeolite Y were synthesized from Class F fly ash and NaOH solution after 2 days of aging at room temperature and 6 days of curing at 80°C. However, no zeolites formed when KOH was used. In additional experiments, a Na–P type zeolite, Zeolite Y, and chabazite developed in cement pastes blended with Class F fly ash and NaOH solution which had been aged 2 days at room temperature and then cured 6 days at temperatures ranging from room temperature to 90°C. Seeding the pastes with natural zeolites was also investigated.     

Mössbauer analysis of iron phases in brown coal ash and fireside deposits

The iron phases present in an electrostatic precipitator ash, an uncooled ash deposit and a cooled superheater ash deposit from Hazelwood Power Station, Australia, burning Morwell brown coal has been examined using Mössbauer spectroscopy. The principal iron phase in the precipitator ash and the uncooled ash deposit from a hot gas offtake was calcium aluminoferrite (Ca₂Fe_{2 ? x}Al_xO₅). Minor amounts of hematite (α-Fe₂O₃) and magnetite (Fe₃O₄) were also detected in the precipitator ash. The cooled superheater ash deposit contained a (Mg, Fe, Al) oxide spinel as the primary iron phase; small quantities of hematite were also detected in this deposit close to the heat exchanger interface. The formation of these iron phases has been rationalized on the basis of the average composition of coal delivered to the power station and supplementary ash chemistry data obtained from other techniques. The evidence suggests that the calcium aluminoferrite in the precipitator ash is derived from inorganic constituents (distributed throughout the coal organic matrix) and the hematite and magnetite are of mineral origin (discrete particles).