In assessing a network's potential performance given possible future disruptions, one must recognize the contributions of the network's inherent ability to cope with disruption via its topological and operational attributes and potential actions that can be taken in the immediate aftermath of such an event. Measurement and maximization of network resilience that accounts for both in the context of intermodal freight transport are addressed herein. That is, the problem of measuring a network's maximum resilience level and simultaneously determining the optimal set of preparedness and recovery actions necessary to achieve this level under budget and level-of-service constraints is formulated as a two-stage stochastic program. An exact methodology, employing the integer L-shaped method and Monte Carlo simulation, is proposed for its solution. Optimal allocation of a limited budget between preparedness and recovery activities is explored on an illustrative problem instance involving a network abstraction of a United States rail-based intermodal container network. 相似文献
The mechanical and adhesive properties of a series of model nanostructured waterborne PSA films have been characterized. The base polymer composition of the latex has been kept constant but systematic modifications have been carried out: the introduction of nanoparticles localized at the interfaces between particles, and the incorporation of a crosslinking agent. The mechanical properties have been characterized and show that the most effective modifications result in an increase in the low‐frequency modulus in the small‐strain regime and in a more pronounced softening and strain‐rate‐dependent behavior in the large‐strain regime. In industrial standard tests, this combination gives a dramatically increased resistance to shear while maintaining a high value of peel resistance.
Abstract: The oxygen consumption rate (OCR) of 2 types of permeabilized tissues and their corresponding isolated mitochondria from porcine M. masseter and liver, resulting in 4 systems, was studied at different pH values (5.0 to 7.1) using fresh samples and samples frozen directly in liquid nitrogen (N2) or air‐frozen at ?20°C. A protocol with the additive sequence rotenone–succinate–ADP (adenosine diphosphate)–cytochrome c–FCCP (carbonyl cyanide p‐trifluoromethoxyphenylhydrazone) was used to study respiration changes. The OCR of liver respiring on succinate (OCR S ) was higher than that of muscle tissue. pH had a larger effect on OCRS than freeze‐thawing. Low pH was associated with reduced OCRS. The OCRS of isolated muscle mitochondria appeared to be an underestimated relative to the OCRS of permeabilized muscle cells. Increasing pH, following prior subjection to pH 5.0, showed partial reversibility of the OCRS. The freeze‐thaw cycle increased the OCRS when muscle systems were frozen and examined above pH 6.0; this effect was less apparent for liver tissue. A response to cytochrome c addition, indicating a defective outer mitochondrial membrane, was observed for all 4 systems. The response was, however, lowest for permeabilized cells. The ADP/FCCP additive pair indicated partial coupling for isolated liver and muscle mitochondria. These additives gave weak responses for the permeabilized liver cells while the OCR seemed to be inhibited for permeabilized muscle fibers when ADP/FCCP was added. Practical Application: The mitochondrial state is believed to be important for myoglobin reduction, development of flavor, and possibly other meat qualities. By monitoring the oxygen consumption in mitochondria and meat we can better understand and control such processes following freezing and thawing. 相似文献
Predictive models were developed for failure times of adhesively bonded titanium and aluminum under a constant stress. The independent variables in the equations were temperature, relative humidity, and stress. The predictive equations were developed using multiple regression analysis which was performed by computer. A comparison of actual failure times with those predicted by the models gave at least an order-of-magnitude agreement. A previously developed reaction rate model was also verified by regression techniques. 相似文献
Emotion and psychopathology researchers have described the fear response as consisting of four main components--subjective affect, physiology, cognition, and behavior. The current study provides evidence for an additional component in the domain of height fear (perception) and shows that it is distinct from measures of cognitive processing. Individuals High (N = 35) and Low (N = 36) in acrophobic symptoms looked over a two-story balcony ledge and estimated its vertical extent using a direct height estimation task (visual matching), and an indirect task (size estimation); the latter task seems to exhibit little influence from cognitive factors. In addition, implicit and explicit measures of cognitive processing were obtained. Results indicated that, as expected, the High Fear group showed greater relative, implicit height fear associations and explicit threat cognitions. Of primary interest, the High (compared to Low) Fear group estimated the vertical extent to be higher, and judged target sizes to be greater, even when controlling for the cognitive bias measures. These results suggest that emotional factors such as fear are related to perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献