Gas sensing properties of columnar CeO2 nanostructures prepared by chemical vapor deposition

Columnar CeO2 nanostructures are grown on alumina substrates by a template- and catalyst-free Chemical Vapor Deposition (CVD) approach and subsequently tested as resistive gas sensors of CH3COCH3, H2, NO2. The sensor response is stable and reproducible throughout the whole working temperature range (200-500 degrees C) and directly dependent on the analyte gas and the adopted operating conditions. The higher sensitivity with respect to that displayed by continuous CeO2 thin films demonstrates the potential of fabricating nanostructured sensing devices characterized by improved functional performances.     

IRIS: Integrated data gathering and interest dissemination system for wireless sensor networks

This paper presents IRIS, an integrated interest dissemination and convergecasting solution for wireless sensor networks (WSNs). The interest dissemination protocol is used to build and maintain the network topology and for task/instruction assignment, while convergecasting implements data gathering at the network sink. Convergecasting heavily exploits cross-layering in that MAC and routing operation are performed jointly and relay selection is based on flexible cost functions that take into account information from different layers. The definition of the IRIS cost function enables tradeoff between key end-to-end performance metrics. In addition, it provides mechanisms for supporting efficient network behavior such as in-network data aggregation or processing. Energy usage is minimized by exploiting density estimation, sleeping modes and duty cycle control in a distributed and autonomous manner and as a function of the traffic intensity. Finally, IRIS is self adaptive, highly localized and imposes limited control overhead. IRIS performance is evaluated through ns2 simulations as well as through experiments on a WSN testbed. Comparative performance results show that IRIS outperforms previous cross-layer solutions. The flexibility introduced by the IRIS cross-layer approach results in higher robustness than that of well-known approaches such as BoX-MAC and CTP.     

Highly nonlinear solitary waves in chains of cylindrical particles

We study the dynamic response of uniform granular chains composed of short cylindrical particles excited by an impulse. The particles in the chains are arranged with their axes orthogonal to the chain’s axis, and the particles maintain a constant relative orientation angle. We study the formation and propagation of solitary waves in the chains varying the orientation angle (α) between particles, and show tunability of the stress transfer as a function of α. We use the general Hertzian contact theory to model the interaction between particles. We compare experimental findings with theoretical predictions based on the long wavelength approximation, and with numerical predictions based on a one-dimensional discrete particle model, and on a three-dimensional finite element approach, finding good agreement.     

Poly(3,4-ethylenedioxythiophene)/Au-nanoparticles composite as electrode coating suitable for electrocatalytic oxidation

Composite materials consisting of poly(3,4-ethylenedioxythiophene) including Au nanoparticles, encapsulated by citrate anions, have been firmly deposited on an electrode surface through a simple method, taking advantage of the interaction between Au metal and thiophene polymeric backbone. A series of similar electrode coatings, also including different amounts of nanoparticles inside, has been characterised in terms of thickness and surface morphology, through different microscopic techniques. The electrocatalytic properties have been studied with respect to the oxidation of glucose in alkaline media, which is prevented from occurring on the pure organic material.     

Correction to Cuevas, Sabina, and Picard (2010).

Reports an error in "Interpersonal victimization patterns and psychopathology among Latino women: Results from the SALAS study" by Carlos A. Cuevas, Chiara Sabina and Emilie H. Picard (Psychological Trauma: Theory, Research, Practice, and Policy, 2010[Dec], Vol 2[4], 296-306). There were citation errors in the last sentence of the first column of text on page 9, and a reference was omitted from the reference list. The sentence should have read: “This result is consistent with other work that has found support for the anxious and dissociative reaction associated with trauma among Latinos and how it may relate to “ataque de nervios” (Hinton, Chong, Pollack, Barlow, & McNally, 2008; Lewis-Fernandez et al., 2002; Schechter et al., 2000; Tolin, Robinson, Gaztambide, Horowitz, & Blank, 2007). (The following abstract of the original article appeared in record 2010-19221-001.) Research on the victimization of Latino women and the subsequent psychological impact has been limited by focusing on individual forms of victimization, primarily partner violence or sexual assault. Another deficiency includes mainly using convenience and/or geographically restricted samples, which impacts the generalizability of the results. To overcome these research limitations, the Sexual Assault Among Latinas (SALAS) study aimed to evaluate the broader scope of victimization among Latino women. The study surveyed a national sample of 2,000 Latino women using random digit dial methodology. Women were asked about various forms of victimization in childhood and adulthood including physical assaults, sexual assaults, stalking, threats, and witnessed violence, as well as psychological symptomatology including depression, anxiety, anger, and dissociation. This analysis found that victimized women were more likely to experience some form of polyvictimization and/or revictimization throughout their lives, with only 36% of victimized women experiencing one form of victimization in childhood or adulthood alone. Furthermore, multiple victimization experiences significantly increased the proportion of women who experienced psychological distress symptoms in the clinical range. For almost all evaluated symptoms, the multiple forms of victimization or varying victimization patterns significantly predicted clinical levels of psychological distress over any specific form or single incident of victimization. The results suggest that victimized Latino women experience multiple forms of victimization and that the evaluation of a broader spectrum of victimization better accounts for pathological symptomatology. Clinical implications for Latino women and future research directions are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Bonding strength of glass-ceramic trabecular-like coatings to ceramic substrates for prosthetic applications

A new approach based on the concepts of quantized fracture mechanics (QFM) is presented and discussed in this paper to estimate the bonding strength of trabecular-like coatings, i.e. glass-ceramic scaffolds mimicking the architecture of cancellous bone, to ceramic substrates. The innovative application of glass-derived scaffolds as trabecular-like coatings is proposed in order to enhance the osteointegration of prosthetic ceramic devices. The scaffolds, prepared by polymeric sponge replication, are joined to alumina substrates by a dense glass-ceramic coating (interlayer) and the so-obtained 3-layer constructs are investigated from micro-structural, morphological and mechanical viewpoints. In particular, the fracture strengths of three different crack propagation modes, i.e. glass-derived scaffold fracture, interface delamination or mixed fracture, are predicted in agreement with those of experimental mechanical tests. The approach proposed in this work could have interesting applications towards an ever more rational design of bone tissue engineering biomaterials and coatings, in view of the optimization of their mechanical properties for making them actually suitable for clinical applications.     

Plasma-assisted synthesis of Ag/ZnO nanocomposites: First example of photo-induced H2 production and sensing

Ag/ZnO nanocomposites were developed by a plasma-assisted approach. The adopted strategy exploits the advantages of Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) for the growth of columnar ZnO arrays on Si(100) and Al₂O₃ substrates, in synergy with the infiltration power of the Radio Frequency (RF)-sputtering technique for the subsequent dispersion of different amounts of Ag nanoparticles (NPs). The resulting composites, both as-prepared and after annealing in air, were thoroughly characterized with particular attention on their morphological organization, structure and composition. For the first time, the above systems have been used as catalysts in the production of hydrogen by photo-reforming of alcoholic solutions, yielding a stable H₂ evolution even by the sole use of simulated solar radiation. In addition, Ag/ZnO nanocomposites presented an excellent response in the gas-phase detection of H₂, opening attractive perspectives for advanced technological applications.     

Bullwhip effect and inventory oscillations analysis using the beer game model

This work examines the bullwhip effect generated and suffered by each level of a four-stage beer game supply chain when different demand scenarios are considered. The paper shows that the actors who generate lower bullwhip are those who suffer more from its effects. Moreover, a new definition of an inventory oscillations measure based on bullwhip definition is introduced. Finally the paper verifies that the new measure of inventory oscillations provides more information on supply chain performance than the bullwhip measure.