Mapping the tack of the pressure-sensitive adhesive joint vs. applied stress and age

A tacky elastomer, the pressure-sensitive adhesive spontaneously bonds with a solid on contact to form a load-bearing pressure-sensitive adhesive joint (PSAJ) that makes many manufactured goods. While the property called the tack of the PSAJ, measured by the green strength of the joint at low applied stress, is vigilantly monitored for quality assurance, it harbors considerable indefinitude because it increases with applied stress and age to span a continuous spectrum that no finite number of discrete empirical readings can fully cover. Assuming the joint strength to be proportional to adhesive/substrate contact area on the atomic level, and treating the contact process as atomic-scale creep, this work determines from first principles the measured tack of a given PSAJ as a function of applied stress and age. The quantitative structure of the function and its implications are explored. The result is tested with published empirical data and used as a basis for mapping the tack spectrum from discrete readings. It brings settlement of long-standing issues such as ranking PSAJs by their non-corresponding tack readings, explaining the disconcertingly high noise : signal ratios plaguing tack data, buffering the uncertainty and extending the domain of tack measurement. It also shows that the tack and the mature joint strength constitute one smooth continuous spectrum.     

Flavonoid Dimers as Bivalent Modulators for P‐Glycoprotein‐Based Multidrug Resistance: Structure–Activity Relationships

Bivalent modulators of P‐glycoprotein : A small library of flavonoid homodimers and heterodimers was synthesized, and their in vitro activity in reversing paclitaxel resistance was evaluated along with structure–activity relationships. SAR trends indicate that flavonoid dimers with nonpolar, hydrophobic, less bulky substituents generally show more potent reversing activity. This will help guide future efforts in the search for more potent compounds.

     

Imparting Ultra‐Low Friction and Wear Rate to Epoxy by the Incorporation of Microencapsulated Lubricant?

The incorporation of microcapsules containing lubricant oil into epoxy composites leads to materials with ultra‐low friction and wear performance. During sliding wear tests, the capsules are damaged by the asperities of the counterface, releasing the oil to the contact area. The lubrication effect of the released oil and the entrapment of wear particles in the cavities left by the ruptured capsules leads to a significant reduction of both the frictional coefficient and the specific wear rate. The approach provides the merits of fluid lubrication but excludes the drawbacks of external lubrication. A minute amount of lubricant oil is sufficient to improve the tribological properties significantly.

     

Securitization,the Global Financial Crisis and Residential Capitalisms in an East Asian Context

This paper offers an analysis of the housing impact of the recent financial crisis in an East Asian context, specifically Hong Kong. In doing so, the paper argues that much of the current political economy analysis in this area has been overly focused on mortgage securitization as the centrepiece of liberal housing finance systems. The paper also shows that an understanding of the limited development of mortgage securitization in Hong Kong lies in the embedded actions of institutional agents. The paper seeks to contribute to ongoing policy debates about the differential impact of the financial crisis on housing markets and to broader theoretical conceptions of ‘residential capitalisms’. In relation to the latter, the aim is to strengthen the East Asian dimension of these discussions and to reinforce arguments regarding the importance of the embedded actions of agents in shaping housing finance systems.     

An adaptive parallel genetic algorithm system for i‐Computing environment

Many real‐world optimization problems in the scientific and engineering fields can be solved by genetic algorithms (GAs) but it still requires a long execution time for complex problems. At the same time, there are many under‐utilized workstations on the Internet. In this paper, we present a self‐adaptive parallel GA system named APGAIN, which utilizes the spare power of the heterogeneous workstations on the Internet to solve complex optimization problems. In order to maintain a balance between exploitation and exploration, we have devised a novel probabilistic rule‐driven adaptive model (PRDAM) to adapt the GA parameters automatically. APGAIN is implemented on an Internet Computing system called DJM. In the implementation, we discover that DJM's original load balancing strategy is insufficient. Hence the strategy is extended with the job migration capability. The performance of the system is evaluated by solving the traveling salesman problem with data from a public database. Copyright © 2003 John Wiley & Sons, Ltd.