Electrode surface treatments in sludge electro-osmosis dewatering

The sewage sludge dewatering produced by wastewater treatment plants (WWTP) is a multifaceted process due to the presence of colloid fractions. Electro-osmosis could be a suitable technique to reduce the water content of the final sludge. Electric fields of 10, 15, and 20?V/cm have been studied for electro-osmosis tests under the pressure of a static or rotating piston, obtaining a dry solids content up to 40–45%, with respect to 25–30% obtained by mechanical methods. In order to optimize the process, the corrosion behavior and the wear of the anodic material appear to be the main critical aspects, due to the high circulating current density and the use of a rotating electrode. We compared the efficiency and the corrosion resistance of dimensionally stable anodes (DSA) with respect to bare stainless steel (AISI 304) and stainless steel coated by PVD technique with TiN, AlTiN, and DLC. Characterization of the anode surfaces by SEM and potentiodynamic tests show that DSA is the most suitable material for our application. However, efficiencies of the electro-osmosis processes have been found comparable, in terms of developed current densities and total energy consumptions, for short-test duration.     

Plasmon-induced photochemical synthesis of silver triangular prisms and pentagonal bipyramids by illumination with light emitting diodes

We have grown silver prisms and pentagonal bipyramids, induced by plasmon excitation on a colloidal solution under the irradiation of light emitting diodes of different colors. Two methods of synthesis of the seeds were tested and their growth evolution recorded, in order to analyze the effect of the chemical synthesis and the color of the irradiation on the morphology and size of the final product. We show that the conversion rate into anisotropic nanoparticles is determined by the chemical environment and the shift of the irradiation wavelength with respect to the plasmon resonance of the seeds. The conversion rate defines the final morphology of the nanoparticles, whereas the size of the nanoparticles is univocally determined by the wavelength of irradiation, irrespective of the method to prepare the seed solution.     

Proposal of visual strength grading rules for Uruguayan pine timber

A previous database with bending and density data of 261 structural size specimens of currently produced Uruguayan slash pine and loblolly pine timber was adjusted to meet testing and characterization requirements of European standards. Visual parameters and mechanical properties for each specimen were evaluated and their relationship was statistically analyzed. Results suggested that all specimens can be grouped in one visual grade with engineered properties similar to those of European C14 strength class. Modulus of elasticity and characteristic bending strength were the defining properties for class assignation.     

Evaluation of the complex hygrothermal behaviors of epoxy–amine systems

In this study, the complex hygrothermal behavior of two epoxy systems used for strengthening applications was studied. In these systems, property loss by plasticization simultaneously occurred with property gain during additional curing. A comparison of the changes in the glass-transition temperature (T_g) and crosslink density with water immersion at different temperatures clearly showed that the two effects of additional curing by a postcuring reaction and plasticization by water absorption were in competition with each other during the exposure. The changes in the conversion with different exposure conditions suggested that water accelerated the postcuring reaction, even at low temperatures; this resulted in a significant difference in the postcuring reaction between unexposed and exposed epoxies. The construction of the plot of T_g versus conversion for the unexposed system and the placement of the T_g for exposed systems onto this master plot provided a method for evaluating the plasticization effect while excluding the influence of additional curing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Formal Metatheory of Programming Languages in the Matita Interactive Theorem Prover

This paper is a report about the use of Matita, an interactive theorem prover under development at the University of Bologna, for the solution of the POPLmark Challenge, part 1a. We provide three different formalizations, including two direct solutions using pure de Bruijn and locally nameless encodings of bound variables, and a formalization using named variables, obtained by means of a sound translation to the locally nameless encoding. According to this experience, we also discuss some of the proof principles used in our solutions, which have led to the development of a generalized inversion tactic for Matita.     

A survey on content-centric technologies for the current Internet: CDN and P2P solutions

One of the most striking properties of the Internet is its flexibility to accommodate features it was not conceived for. Among the most significant examples, in this survey we consider the transition of the Internet from a reliable fault-tolerant network for host-to-host communication to a content-centric network, i.e. a network mostly devoted to support efficient generation, sharing and access to content. We survey this research area according to a top-down approach. We present a conceptual framework that encompasses the key building blocks required to support content-centric networking in the Internet. Then we describe in detail the two most important types of content-centric Internet technologies, i.e., Content-Delivery Networks (CDNs) and P2P systems. For each of them, we show how they cover the key building blocks. We then identify the functional components of CDN and P2P content management solutions, and discuss the main solutions proposed in the literature for each of them. We consider different types of content (both real time and non real time), and different networking environments (fixed, mobile, …). Finally, we also discuss the main recent research trends focused on how to design the Future Internet as a native content-centric network.     

巨人的花园——对不同尺度棕地的差异化策略

近几十年来，旧工业区转型的项目不断增加，范围日益扩大，内涵不断扩充，被认为是城市改造的主要途径。工业区的转型不仅是自身的需要，而且经常能提供一个现实的机会来设想与城市在功能和关系上的深远变化。因为实施的连续性和话题的扩展性，这种转型要放在社会、技术和国际化变化的语境下，考虑典型的城市改造过程中的周期性活力，作为持续演变的效果来进行分析。这种改善往往受到多方面影响，包括：该地区最初的设计、与城市中断了的互动、新的机遇以及潜在的需求。所以，转型不仅意味着现存物质空间的改变，往往还作为观念工具，提供区域层面的解决之道。     

Detecting component changes at run time with behavior models

Modern software systems are composed of several services which may be developed and maintained by third parties and thus they can change independently and without notice during the system’s runtime execution. In such systems, changes may possibly be a threat to system functional correctness, and thus to its reliability. Hence, it is important to detect them as soon as they happen to enable proper reaction. Change detection can be done by monitoring system execution and comparing the observed execution traces against models of the services composing the application. Unfortunately, formal specifications for services are not usually provided and developers have to infer them. In this paper we propose a methodology which exactly addresses these issues by using software behavior models to monitor component execution and detect changes. In particular, we describe a technique to infer behavior model specifications with a dynamic black box approach, keep them up-to-date with run time observations and detect behavior changes. Finally, we present a case study to validate the effectiveness of the approach in component change detection for a component that implements a complex, real communication protocol.