Effect of interparticle interaction on the low temperature oxidation of CO over size-selected Au nanocatalysts supported on ultrathin TiC films

This work aims to get insight into the influence of interparticle interactions on catalysis. The low temperature CO oxidation is used as a model reaction. A strong dependence of the catalytic activity and stability of gold nanoparticles uniformly dispersed on polycrystalline TiC films was observed as a function of the interparticle distance. Two samples with similar height distributions (∼2 nm), but with different average interparticle distances (∼30 and ∼80 nm), were synthesized using diblock copolymer encapsulation. Their chemical reactivity was investigated by temperature programmed desorption (TPD), and reactive coarsening and subsequent deactivation was observed for the sample with the smallest interparticle distance. The system with the largest average interparticle distance showed higher stability towards agglomeration and longer lifetime.     

“Today I Tell” A Comics and Story Creation App for People with Autism Spectrum Condition

ABSTRACT

This article describes the design, development, and evaluation of an application to help people with autism spectrum condition (ASC) express themselves through the creation of stories and comics. The intended platform of the application is touchscreen devices. The design process follows a human-centered design approach involving caregivers, teachers, usability experts, primary school students, and people with ASC. The characteristics considered are explained to design and implement the application, as well as the different evaluation steps. The prototype design was evaluated with 36 experts (teachers, caregivers, and usability experts). Next, 14 primary school students and 10 participants from a special education institution tested the application. Among all the participants, five students of the primary school institution have attention-deficit hyperactivity disorder and five students of the special education institution had ASC. The feedback gathered shows the importance of multidisciplinary teams in developing an application aimed at people with special needs. Non-functional features such as usability and accessibility can be bypassed by developers and this is the point at which teachers, caregivers, usability experts, and even the end users of the application can provide their insights in order to improve the product during its development phase. This also reduces the costs that would be incurred if the final product had to be changed after its development.     

Characterization of a p‐nitrophenol‐degrading mixed culture with an improved methodology of fluorescence in situ hybridization and confocal laser scanning microscopy

BACKGROUND: Confocal laser scanning microscopy (CLSM) provides critical information of the presence of autofluorescence signals inherent to the samples under study, which may interfere with probe fluorescence. Therefore, it is important to determine the emission spectrum of the biomass autofluorescence under study in order to avoid, as much as possible, this wavelength range when selecting specific probe emissions and to modify, if necessary, the original fluorescence in situ hybridization (FISH) protocol in order to enhance probes signals. RESULTS: Microbial characterization of a p‐nitrophenol‐degrading activated sludge through a conventional FISH protocol was not possible because the fluorescence signal of the unlabelled cells was similar to or even higher than the signal emitted by hybridized cells, impeding the separation of the two signals and therefore, preventing biomass characterization. An optimized but simple FISH approach was developed in order to ease observation of the p‐nitrophenol‐degrading bacteria studied in this work. The final results allowed identification of Arthrobacter sp. (Micrococcaceae family) and genus Acinetobacter (Moraxellaceae family) in the p‐nitrophenol‐degrading activated sludge, whereas no hybridization was found for Pseudomonas spp. CONCLUSIONS: The hypothesis of a mixed culture following, at the same time, different degradation pathways has been confirmed through the microbial characterization of enriched p‐nitrophenol‐degrading activated sludge. Copyright © 2011 Society of Chemical Industry     

$${ SIM}^2{ RRAM}$$: a physical model for RRAM devices simulation

In the last few years, resistive random access memory (RRAM) has been proposed as one of the most promising candidates to overcome the current Flash technology in the market of non-volatile memories. These devices have the ability to change their resistance state in a reversible and controlled way applying an external voltage. In this way, the resulting high- and low-resistance states allow the electrical representation of the binary states “0” and “1” without storing charge. Many physical models have been developed with the aim of understanding the mechanisms that control the resistive switching. In this work, we have compiled the main theories accepted as well as their corresponding models for the conduction characteristics. In addition, simulation tools play a very important role in the task of checking these theories and understanding these mechanisms. For this reason, the simulation tool called \(\hbox {SIM}^{2}\hbox {RRAM}\) has been presented. This simulator is capable of replicating the global behavior of RRAM cell based on \(\hbox {HfO}_{x}\).     

Order Barrier for Low-Storage DIRK Methods with Positive Weights

In this paper we study an order barrier for low-storage diagonally implicit Runge–Kutta (DIRK) methods with positive weights. The Butcher matrix for these schemes, that can be implemented with only two memory registers in the van der Houwen implementation, has a special structure that restricts the number of free parameters of the method. We prove that third order low-storage DIRK methods must contain negative weights, obtaining the order barrier \(p\le 2\) for these schemes. This result extends the well known one for symplectic DIRK methods, which are a particular case of low-storage DIRK methods. Some other properties of second order low-storage DIRK methods are given.     

Face recognition using a permutation coding neural classifier

Face recognition is an important security task. We propose a high-level method to solve this problem: a permutation coding neural classifier (PCNC). A PCNC with a special feature extractor for face image recognition systems is a relatively new method that has been tested with good results to classify real environment images (such as larvae of various types and handmade elements). As baseline methods, a support vector machine (SVM) and the iterative closest point (ICP) method are selected for comparison. We applied these methods to gray-level images from the FRAV3D face database. Fifteen experiments were performed to examine a large set of training and testing conditions. As a general result, it was observed that errors are lower with the PCNC than with the SVM and the ICP classifier. We aggregated various distortions for the initial images to improve the PCNC. We analyze and discuss the obtained results.     

Production of bacterial nanocellulose from wine industry residues: Importance of fermentation time on pellicle characteristics

Bacterial nanocellulose (BNC) was produced by Gluconacetobacter xylinus under static conditions using grape pomace extract (the most abundant residue of the wine industry) as a carbon source and corn steep liquor (a byproduct of corn wet‐milling) as the main nitrogen source. Carbon and nitrogen source concentrations, as well as inocula size, fermentation time, and temperature, were all considered in order to maximize BNC production by the use of statistically designed experiments and the response surface methodology. At optimum production conditions, the effect of fermentation time on morphology, solids content, chemical structure, crystallinity, thermal decomposition pattern, and storage modulus of dried BNC pellicles was analyzed. The results evidenced that dried BNC pellicles that were incubated for longer times showed higher thermal stability, higher crystallinity, and higher storage modulus, resulting from a denser nanoribbons network. All of these characteristics will certainly play a role in the performance of BNC in practical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43109.     

Metal-free electrocatalysts obtained from agave waste by solar pyrolysis for oxygen reduction reaction

Characterization and electrochemical evaluation of novel metal-free electrocatalysts obtained by solar pyrolysis is reported. Carbon-based electrocatalysts were prepared from agave bagasse waste, using a sustainable process based on concentrated solar energy as heat source. Agave was processed in a spherical borosilicate glass solar reactor using a heating rate of 30 °C min^?1 to a target of 500, 700, or 900 °C, and maintaining temperature for 1 h under inert atmosphere. The structure and composition of the prepared electrocatalysts were influenced by pyrolysis temperature. In addition, electrocatalytic activity towards the oxygen reduction reaction in 0.1 M KOH solution was explored. The electrocatalyst obtained at 500 °C showed the highest activity among all pyrolyzed samples due to its moderate surface area, but mostly due to its higher oxygen content. The metal-free electrocatalysts reported in this work are promising eco-friendly alternative as cathode materials for anion-exchange membrane fuel cells. This study provides a sustainable approach to use agricultural biomass waste to produce valuable materials for electrochemical energy devices.