Morphology and properties of thermoplastic polyurethane composites incorporating hydrophobic layered silicates

Polyurethane (PU) composites incorporating Cloisite 15A (15A) were prepared via melt compounding and solvent casting. The melt‐compounded composites had better dispersion and a smaller silicate stack size as a result of the higher shear forces associated with twin‐screw extrusion. The PU microphase separation and hard domain order were greater in the melt‐processed materials. At the concentrations of 15A employed in this study (≤7 wt %), the filler did not have an observable effect on the microphase texture of either the solvent‐ or melt‐processed PU. The tensile properties of the melt‐compounded materials were lower than those of their solvent‐cast counterparts because of thermal degradation. The solvent‐cast composite containing a 3 wt % loading of 15A displayed improved tensile strength and elongation, primarily because of plasticization by the silicate organic treatment. The addition of layered silicates with high aspect ratios increased the hysteresis and permanent set of this PU elastomer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 300–309, 2005     

Investigation of high-pressure micro jet technology as an alternative to diamond disc conditioning in ILD CMP

The efficacy of an alternative to conventional diamond conditioning in chemical mechanical planarization (CMP) was evaluated in this study. The high pressure micro jet (HPMJ) system sprays ultra-pure water (UPW) at pressures ranging from 10 to 20 MPa onto a CMP pad to clean the pad of slurry residue, remove embedded slurry particles, and re-establish pad asperities. The system is employed in an ex situ fashion and is compared to in situ and ex situ diamond conditioning as well as using no conditioning. Real-time frictional force acquisition allows for coefficient of friction (COF) analysis, which indicates the extent of pad wear. Removal rate analysis, SEM imagery, and pad surface profilometry are also used to evaluate HPMJ as an alternative conditioning technology. Removal rates significantly lower than those associated with diamond conditioning are obtained for the HPMJ system when UPW conditioning is directly followed by polishing. SEM imagery and pad profilimetry indicate these low HPMJ removal rates are due to differences in pad surface chemistry, not pad surface topography. Experiments including a 30 s silicon wafer polish with slurry following HPMJ conditioning to re-establish pad surface chemistry were performed and result in removal rates that are comparable to those obtained using ex situ conditioning. The removal rates obtained using HPMJ conditioning for relative wafer-platen velocities of 0.31 and 0.62 m/s are 8 and 1% higher than those obtained using ex situ diamond conditioning and 18% lower than those obtained using ex situ diamond conditioning for 0.93 m/s. The average COF values for HPMJ conditioning using the intermediate silicon wafer polishes are 15% lower than average COF values associated with ex situ diamond conditioning, suggesting a possible increase in pad life for the HPMJ system.     

Social Disadvantage, Tenure and Location: An Analysis of Sydney and Melbourne

This article focuses on the role that housing markets play in structuring patterns of social disadvantage in Australian cities, specifically Sydney and Melbourne. It explores the relationship between housing tenure and social disadvantage at the local scale (Census collector districts) for the two cities, following a discussion of the various stands of literature on housing tenure and socio-spatial polarisation in Australian cities. It analyses the relationship between areas of high social disadvantage and housing tenure. The analysis, which uses the ABS Index of Disadvantage, distinguishes locations where comparable levels of social disadvantage are associated with very different housing markets, one where public housing is prominent and others which are primarily areas of private sector housing. The social profiles of both types of area are described, drawing out differences between the two cities, as are changes in the extent of these areas over time. The policy implications for the areas of private sector housing are then discussed.     

Taste and olfactory intensity perception changes following left insular stroke.

The authors tested suprathreshold intensity perception of gustatory and olfactory stimuli in a 70-year-old right-handed man following a left posterior insular stroke and compared his results with those of age-matched controls. Both modalities revealed significant differences between left (ipsilateral to lesion) and right (contralateral) ratings of intensity. In both gustation and olfaction, these differences were driven primarily by trends toward increased contralateral sensitivity relative to controls. Intensity changes were most pronounced for unpleasant odors and for tastes perceived strongly as either pleasant (sweet) or unpleasant (salty, bitter). These results show that a left posterior insula lesion may affect taste and olfactory perception similarly by increasing sensitivity contralateral to the lesion. One possible mechanism is release from inhibition at the cortical level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The moderating role of subordinate political skill on supervisors' impressions of subordinate ingratiation and ratings of subordinate interpersonal facilitation.

Nearly 2 decades ago, social influence theorists called for a new stream of research that would investigate why and how influence tactics are effective. The present study proposed that political skill affects the style of execution of influence attempts. It utilized balance theory to explain the moderating effect of employee political skill on the relationships between self- and supervisor-reported ingratiation. Additionally, supervisor reports of subordinate ingratiation were hypothesized to be negatively related to supervisor ratings of subordinate interpersonal facilitation. Results from a combined sample of 2 retail service organizations provided evidence that subordinates with high political skill were less likely than those low in political skill to have their demonstrated ingratiation behavior perceived by targets as a manipulative influence attempt. Also, when subordinates were perceived by their supervisors to engage in more ingratiation behavior, the subordinates were rated lower on interpersonal facilitation. Implications of these findings, limitations, and future research directions are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simplified thermal model to support analysis of urban resource flows

As part of a project to simulate the energy flows within urban districts, this paper describes a simplified model to simulate heat flows in buildings. Taking a standard two-node resistance–capacitance model as a starting point, we discuss developments to improve the handling of external surface radiant and convective energy exchanges, internal convective exchanges and the placement of capacitance in multi-layer walls. We also describe the extension of the model to solve for a building with an arbitrary number of zones, accounting for the capacitance of separating walls. Comparisons with ESP-r for a range of building configurations show that in general the model reproduces well both aggregate energy demands and their temporal characteristics (likewise with internal temperature). The paper closes by discussing the computational implementation of the model and its coupling with the integrated urban energy modelling tool.     

Fluid–structure interaction modeling of ringsail parachutes with disreefing and modified geometric porosity

Fluid?Cstructure interaction (FSI) modeling of parachutes poses a number of computational challenges. These include the lightness of the parachute canopy compared to the air masses involved in the parachute dynamics, in the case of ringsail parachutes the geometric porosity created by the construction of the canopy from ??rings?? and ??sails?? with hundreds of ??ring gaps?? and ??sail slits,?? in the case of parachute clusters the contact between the parachutes, and ??disreefing?? from one stage to another when the parachute is used in multiple stages. The Team for Advanced Flow Simulation and Modeling (T?AFSM) has been successfully addressing these computational challenges with the Stabilized Space?CTime FSI (SSTFSI) technique, which was developed and improved over the years by the T?AFSM and serves as the core numerical technology, and a number of special techniques developed in conjunction with the SSTFSI technique. The quasi-direct and direct coupling techniques developed by the T?AFSM, which are applicable to cases with nonmatching fluid and structure meshes at the interface, yield more robust algorithms for FSI computations where the structure is light. The special technique used in dealing with the geometric complexities of the rings and sails is the homogenized modeling of geometric porosity (HMGP), which was developed and improved in recent years by the T?AFSM. The surface-edge-node contact tracking (SENCT) technique was introduced by the T?AFSM as a contact algorithm where the objective is to prevent the structural surfaces from coming closer than a minimum distance in an FSI computation. The recently-introduced conservative version of the SENCT technique is more robust and is now an essential technology in the parachute cluster computations carried out by the T?AFSM. As an additional computational challenge, the parachute canopy might, by design, have some of its panels and sails removed. In FSI computation of parachutes with such ??modified geometric porosity,?? the flow through the ??windows?? created by the removal of the panels and the wider gaps created by the removal of the sails cannot be accurately modeled with the HMGP and needs to be actually resolved during the FSI computation. In this paper we focus on parachute disreefing, including the disreefing of parachute clusters, and parachutes with modified geometric porosity, including the reefed stages of such parachutes. We describe the additional special techniques we have developed to address the challenges involved and report FSI computations for parachutes and parachute clusters with disreefing and modified geometric porosity.