Electrical properties of Ca-doped ceria electrolytes prepared by proteic sol-gel route and by solid-state reaction using mollusk shells

Ca-doped ceria (CCO) electrolytes were prepared using two processing approaches, proteic sol-gel synthesis using gelatin (SG) and solid-state reaction (SSR). Mollusk shell powder was used in the SSR method as the main source of Ca. Materials sintered at 1350–1450 °C exhibited relative density above 95% and different microstructural features regarding grain size and morphology. Impedance spectroscopy in air revealed a comparatively better total electrical response of materials prepared by the proteic sol-gel route. CCO ceramics prepared by the SG route have bulk conductivity four times higher than the highest conductivity of samples processed by the SSR route. Electrical properties of the grain boundaries of both series of materials reveal distinct oxygen vacancy concentration profiles and space charge potentials. The role of processing route and sintering schedules was discussed taking into consideration the distinct impact of Ca interaction in the grain boundaries.     

Antifeedant and toxic effects of sesquiterpenes fromSenecio palmensis to colorado potato beetle

A bioassay-guided fractionation of the aerial parts ofSenecio palmensis resulted in the isolation of two sesquiterpenes, 2,10-bisaboladien-1-one and 11-acetoxy-5-angeloyloxy-silphinen-3-one. The bisabolene and the silphinene represented 0.012% and 0.024% of the plant dry weight, respectively. Both compounds showed antifeedant activity againstLeptinotarsa decemlineata larvae and adults in short-term choice and no-choice bioassays. Both compounds were also tested against different species of phytopathogenic fungi. The beetles were more sensitive to these compounds in choice than in no-choice assays, with a gradient of increasing sensitivity from second instars to adults. Bisabolene was 45 times less active as an antifeedant than juglone, which was tested as a positive control. The silphinen was more active than the bisabolene, with a range of activity similar to juglone. Furthermore, exposure of fourth instars to these compounds over a 24-hr period resulted in reduced feeding and growth rates. To distinguish between antifeedant and toxic effects, growth efficiencies were calculated as the slope of the regression of relative growth rate on relative consumption rate. The comparison of these results with those of antifeedant simulation and contact toxicity bioassays indicates that feeding inhibition is the primary mode of action of the bisabolene, while the silphinene shows both antifeedant and toxic effects.     

Molecular structures and vibrational frequencies for cis-[PdCl2(tmen)] and cis-[Pd(N3)2(tmen)]: A DFT study

Theoretical molecular structures of the complexes cis-[PdCl₂(tmen)] and cis-[Pd(N₃)₂(tmen)] (tmen = N,N,N′,N′-tetramethylethylenediamine) were investigated using B3LYP/DFT method. The calculated molecular parameters, bond distances and angles, revealed a square-planar geometry around the metallic center for both compounds with the azide being linear. The theoretical infrared spectra of C₁ symmetry (electronic state ¹A) of the compounds are in agreement with the experimental data.     

Structural study of the salivary glands of Anocentor nitens (Acari: Ixodidae) during the feeding cycle

The salivary glands of Anocentor nitens (Neumann, 1897 ) occur in pairs and are located in the anterolateral region of the general cavity, with milky white color and approximately equal sizes. They consist of a secretory portion and an excretion duct. In some glandular acini, all the cells had a basophilic appearance they were stained by hematoxylin, whereas others presented cells with different staining affinities. In this work, we describe the variations observed in these glands during the feeding cycle of ticks [after feeding (0 h) and successively at 24, 48, 72, 96, 120, and 144 h]. The cells stained by hematoxylin were shown to be more reactive to Alcian blue, thus demonstrating the presence of acid glycosaminoglycans, whereas those stained using eosin presented weak or no reaction. A strong reaction was found by the use of the periodic acid‐Schiff (PAS) technique, thereby suggesting the presence of glycogen and/or glycoconjugates containing hexose, confirmed by using salivary amylase before PAS, with partial destaining of the slides. Continuing presence of residual staining in these cells suggests the presence of glycoconjugates containing hexose. Cells with nuclei of circular outline and few granules (of different sizes) were found in type II acini, 72 h after collection. Type I acini presented wide lumina and walls composed of larger numbers of cells of cubic to cylindrical shape. The pronounced degranulation shown in this study over the course of the feeding cycle was associated with the release of substances for oviposition. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.     

Evaluation of the EC8-3 confidence factors for the characterization of concrete strength in existing structures

A probabilistic framework is defined to evaluate the values of the Confidence Factors (CFs) proposed in Eurocode 8 Part 3 (EC8-3) for the characterization of material properties. This evaluation is presented for the concrete compressive strength but its validity for other material properties can also be inferred from the results obtained. The number of material tests and the existence of prior knowledge are the essential aspects for the CF quantification. The probabilistic framework proposed in the first part of the study does not consider the existence of prior knowledge and is based on the concept of confidence intervals. In the second part of the study, the effects of prior knowledge are considered using a Bayesian framework. The combination of testing data obtained from different types of tests is also addressed as an extension of the referred Bayesian approach. Results indicate that the EC8-3 proposed CFs for KL1 and KL2 are adequate, but for KL3 it is suggested that a larger value should be used.     

An Adaptive Programming Model for Fault-Tolerant Distributed Computing

The capability of dynamically adapting to distinct runtime conditions is an important issue when designing distributed systems where negotiated quality of service (QoS) cannot always be delivered between processes. Providing fault tolerance for such dynamic environments is a challenging task. Considering such a context, this paper proposes an adaptive programming model for fault-tolerant distributed computing, which provides upper-layer applications with process state information according to the current system synchrony (or QoS). The underlying system model is hybrid, composed by a synchronous part (where there are time bounds on processing speed and message delay) and an asynchronous part (where there is no time bound). However, such a composition can vary over time, and, in particular, the system may become totally asynchronous (e.g., when the underlying system QoS degrade) or totally synchronous. Moreover, processes are not required to share the same view of the system synchrony at a given time. To illustrate what can be done in this programming model and how to use it, the consensus problem is taken as a benchmark problem. This paper also presents an implementation of the model that relies on a negotiated quality of service (QoS) for communication channels     

Removal of Cd2+, Cu2+, Ni2+, and Pb2+ ions from aqueous solutions using tururi fibers as an adsorbent

This work investigates the removal of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ ions from aqueous solutions using tururi fibers as an adsorbent under both batchwise and fixed‐bed conditions. It was found that modification of the tururi fibers with sodium hydroxide increased the adsorption efficiencies of all metal ions studied. The fractional factorial design showed that pH, adsorbent mass, agitation rate, and initial metal concentration influenced each metal adsorption differently. The kinetics showed that multi‐element adsorption equilibria were reached after 15 min following pseudo‐second‐order kinetics. The Langmuir, Freundlich, and Redlich–Peterson models were used to evaluate the adsorption capacities by tururi fibers. The Langmuir model was found to be suitable for all metal ions. Breakthrough curves revealed that saturation of the bed was reached in 160.0 mL with Cd²⁺ and Cu²⁺, and 52.0 mL with Ni²⁺ and Pb²⁺. The Thomas model was applied to the experimental data of breakthrough curves and represented the data well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40883.     

Microencapsulation of lycopene by spray drying: Characterization, stability and application of microcapsules

Microencapsulation can be an alternative to minimize lycopene instability. Thus, the aim of this study was to microencapsulate lycopene by spray drying, using a modified starch (Capsul^®) as an encapsulating agent, and to assess the functionality of the capsules applying them in cake. The quantity of lycopene was varied at 5, 10 and 15% in a solution containing 30% of solids in order to obtain the microcapsules. These microcapsules were evaluated as to encapsulation efficiency and morphology and then submitted to a stability test and applied in cakes. Encapsulation efficiency values varied between 21 and 29%. The microcapsules had a rounded outer surface with the formation of concavities and they varied in size. The stability test revealed that microencapsulation offered greater protection to lycopene compared to its free form and it was observed that the microcapsules were able to release pigment and color the studied food system in a homogenous manner.     

Impact of moisture and plasticizer properties on polymer–plasticizer physical mixing performance

The ability for polymers and additives to physically mix in many industrial applications is dictated by a combination of kinetic and thermodynamic factors. The presence of moisture may complicate the mixing performance as water can interact at various degrees with each of the components; this depends on the hydrophilicity of the materials. In this study, the physical mixing behavior of a ternary system consisting of a hygroscopic polymer (copovidone), a plasticizer, and water was examined. Three different liquid plasticizers with a range of hydrophilic–lipophilic properties and viscosities were evaluated for their physical mixing performance and the impact of their water content. Inverse gas chromatography was introduced as a new method for measuring the surface characteristics of the physical mixtures to quantify the mixing performance. Through the application of the Flory–Huggins model to understand the thermodynamic behavior of the system, it was shown that mixing was less effective in a system of high water content for a hydrophobic plasticizer. However, the underlying thermodynamic unfavorability of such a system could be overcome by kinetic influence to provide a good mixing performance. Specifically, as the viscosity of the plasticizer decreased, the influence of the thermodynamic characteristics was found to become less apparent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41679.