Direct stamping of silver nanoparticles toward residue-free thick electrode

Direct stamping of functional materials has been developed for cost-effective and process-effective manufacturing of nano/micro patterns. However, there remain several challenging issues like the perfect removal of the residual layer and realization of high aspect ratio. We have demonstrated facile fabrication of flexible strain sensors that have microscale thick interdigitated capacitors with no residual layer by a simple direct stamping with silver nanoparticles (AgNPs). Polyurethane (PU) prepolymer was utilized as an adhesive layer to transfer AgNPs more efficiently during the separation step of the flexible stamp from directly stamped AgNPs. Scanning electron microscopy images and energy dispersive x-ray spectroscopy analysis revealed residue-free transfer of microscale thick interdigitated electrodes onto two different flexible substrates (elastomeric and brittle) for the application to highly sensitive strain sensors.     

Assessment of the crack growth characteristics at the low fatigue limit of a multi-pass welded Ni-based alloy 617

It has become known that the most effective methodology for green power plant systems is to increase the generating efficiency of steam power plants. Among the materials developed to improve the performance, it is known that the most practical and applicable materials are Ni-based Alloys. However, it is necessary to first guarantee mechanical reliability of the weld for applying these Ni-based Alloys. In this study, firstly, the fatigue strength of multi-pass welded Ni-based Alloy 617 in as-welded and post weld heat-treated conditions were assessed. And then the crack growth characteristics at the low fatigue limit of them were assessed. From the results, fatigue strength of the welds those were post weld heat treated did not show large difference compare to not heat-treated ones. These results mean that the weld of Ni-based Alloy 617 is not influenced remarkably by post weld heat treatment in the metallurgical and mechanical changes. However, it was found that the fatigue crack grew at the low fatigue limit, which was about 48.4% (327 MPa) of the static tensile strength (675.1 MPa) of the weld, and 43.1% of the base material (759.4 MPa).     

Predicting the Lifespan and Retweet Times of Tweets Based on Multiple Feature Analysis

In social network services, such as Facebook, Google+, Twitter, and certain postings attract more people than others. In this paper, we propose a novel method for predicting the lifespan and retweet times of tweets, the latter being a proxy for measuring the popularity of a tweet. We extract information from retweet graphs, such as posting times; and social, local, and content features, so as to construct prediction knowledge bases. Tweets with a similar topic, retweet pattern, and properties are sequentially extracted from the knowledge base and then used to make a prediction. To evaluate the performance of our model, we collected tweets on Twitter from June 2012 to October 2012. We compared our model with conventional models according to the prediction goal. For the lifespan prediction of a tweet, our model can reduce the time tolerance of a tweet lifespan by about four hours, compared with conventional models. In terms of prediction of the retweet times, our model achieved a significantly outstanding precision of about 50%, which is much higher than two of the conventional models showing a precision of around 30% and 20%, respectively.     

Optimal replacement strategy for stochastic deteriorating system with random wear limit under periodic inspections

In this paper, we examine the preventive maintenance policies for systems/items which are degraded continuously in time and the degree of deterioration that can be observed through periodic inspection. The items will be replaced preventively if the wear process exceeds a limit at periodic inspection or replaced immediately on failure. The limit is assumed to be random in taking individual variation to withstand damages or unmeasurable variables latent to failure into account. Continuous wear process is modeled via a gamma process. We derive an optimal wear limit for preventive replacement so that the long-run total expected cost per unit time is minimized. The proposed method is applied to a problem of block mat inspection for the barrier’s seabed protection.     

La0.8Sr0.2Cr0.95Ru0.05O3−x and Sm0.8Ba0.2Cr0.95Ru0.05O3−x as partial oxidation catalysts for diesel

La_0.8Sr_0.2Cr_0.95Ru_0.05O_3−x (LSCR) and Sm_0.8Ba_0.2Cr_0.95Ru_0.05O_3−x (SBCR), Ru-substituted perovskite catalysts, are investigated for the partial oxidation (POX) of diesel to produce hydrogen-rich gases for fuel cell applications. Metal-substituted perovskite materials have been investigated as reforming catalysts because the metal atoms are well-dispersed in the perovskite structure. However, Ru de-mixing and a secondary phase of LSCR and SBCR are observed after reduction at high temperature. The thermal stability, sulfur tolerance and aromatic decomposition over LSCR and SBCR are compared to those over Ru on Ce_0.9Gd_0.1O_2−x (CGO). During the thermal stability test, the catalytic activities of LSCR and SBCR improve after operating at 1000 °C. The sulfur tolerance and aromatic decomposition activity of LSCR and SBCR improve when the temperature increases to 950 °C. The improvements are attributed to the de-mixed Ru from the perovskite structure at high temperatures under a reductive atmosphere.     

Who will cross the border? – The transition of political discussion into the newly emerged venues

This study explores the political implications of new communication technologies with a focus on their role as political discussion venues. Assuming that new technologies could expand the sphere for political discourse, we investigate the transition of citizens’ face-to-face political discussion into the computer-mediated online context. With analyses of a representative sample of US adults, this study explicates the link between the traditional and newly emerged discussion venues online. Our results reveal that significant differences in the transition pattern arise from variances in citizens’ political interest and age. In addition, in an attempt to reconcile the two seemingly conflicting hypotheses, we examine the role of political interest and age in the transition process within one integrated theoretical framework. Our findings highlight the conditions under which the democratic potential of the new venues becomes magnified, and draws attention to the importance of examining the dynamics underlying the transition of discussion venues.     

Reinforcement Q-learning based on Multirate Generalized Policy Iteration and Its Application to a 2-DOF Helicopter

International Journal of Control, Automation and Systems - In this paper, we propose a novel Q-learning method based on multirate generalized policy iteration (MGPI) for unknown discrete-time (DT)...     

A time-varying lot sizes approach for the economic lot scheduling problem with returns

We consider the economic lot scheduling problem with returns by assuming that each item is returned by a constant rate of demand. The goal is to find production frequencies, production sequences, production times, as well as idle times for several items subject to returns at a single facility. We propose a heu ristic algorithm based on a time-varying (TV) lot sizes approach. The problem is decomposed into two distinct portions: in the first, we find a combinatorial part (production frequencies and sequences) and in the second, we determine a continuous part (production and idle times) in a specific production sequence. We report computational results that show that, in many cases, the proposed TV lot sizes approach with consideration of returns yields a relatively minor error.