One-step synthesis of composite electrolytes of Eu-doped ceria and alkali metal carbonates

Europium-doped ceria (EDC, Ce_0.9Eu_0.1O_2−δ)/alkaline carbonate (LNC, (Li,Na)₂CO₃) composite ceramics prepared through a one-step citrate-based route were analyzed by powder X-ray diffraction, infrared and laser Raman spectroscopies as well as scanning and transmission electron microscopy. The electrochemical behavior of the electrolyte material was studied by impedance spectroscopy in air, CO₂ and N₂ + H₂ (90/10 vol%, respectively) gas mixtures, in the temperature range 300–600 °C. The sub micrometric and even nanosized ceramic particles appeared as merged inside the mixed carbonates, with modest grain to grain necking. The EDC/LNC composite electrolytes showed a conductivity of 0.27 S cm⁻¹ at 600 °C in air, amongst the best ever reported, exceeding the usual requirements for fuel cell applications.     

Range-to-cone-length relations for light ions in Cr

Curves of “range × cone length” and “diameter × cone length” are calculated for tracks left by low-energy light ions in ³⁹Cr. The calculations cover ions from helium to iron and are performed for 6.25N NaOH at 70°C and a standard etching time but can be easily extended to other etching conditions.     

Simultaneous measurement of temperature and strain based on arc-induced long-period fibre gratings

A study on arc-induced long-period fibre gratings (LPFGs) revealed that their strain sensitivity depends on the electric current of the arc discharge. Based on that property, a sensor scheme comprising two concatenated LPFGs was implemented for discrimination of temperature and strain effects. This sensor presented resolutions of /spl plusmn/0.1/spl deg/C//spl radic/Hz and /spl plusmn/35 /spl mu//spl epsiv///spl radic/Hz, respectively.     

Iterative Frequency-Domain Packet Combining Techniques for UWB Systems with Strong Interference Levels

UWB (Ultra Wideband) systems tend to suffer strong interference from signals that occupy a significant part of the transmission band. This is an important constraint, especially when the channel remains fixed for a long period of time. In order to overcome this limitation, this paper considers UWB systems employing Single-Carrier with Frequency-Domain Equalization techniques. We propose the corresponding receiver, which also allows the soft packet combining associated to different Automatic Repeat ReQuest transmission attempts, as a measure to improve the performance through the exploitation of diversity. Our techniques are able to cope with strong interference levels as well as deep fading, even for fixed channels.     

Diamond-like carbon deposited by plasma technique as a function of methane flow rate

Diamond-like carbon (a-C:H) prepared by plasma enhanced chemical vapor deposition (PECVD) as a function of methane gas flow rate is reported. Films deposited at zero flow rate, i.e., without the use of vacuum pumps during the deposition, are also investigated. For that purpose, the reactor chamber was baked and pumped down to about 10^?8 Torr to reduce contamination released from the reactor walls. The films were analyzed by visible, infrared and Raman spectroscopes. It was observed that the deposition rate, hydrogen concentration and optical gap depend on the methane gas flow rate. A maximum for deposition rate found at methane flow was much smaller than the flow usually adopted in conventional procedures.     

Everyday Conversation in the Deliberative Process: An Analysis of Communicative Exchanges in Discussion Groups and Their Contributions to Civic and Political Socialization

This article aims to investigate the forms of interaction and communicative exchanges in discussion groups composed of beneficiaries of a Brazilian income transfer program (Bolsa‐Família Program) and how these forms contribute to the deliberative process. Discussion groups are used as a method for showing how everyday conversation and political discussion are interrelated. Thus, this article is an empirical investigation that—within the theoretical deliberative democracy framework—helps to make explicit concrete situations within which fluid and disperse conversations change toward attitudes that include taking the risk of expressing dissonant opinions, explaining background assumptions, and producing counternarratives. We contend that informal conversation is part of the dynamics that prepare citizens for more demanding and formal deliberations.     

Comparison of glycemic index of spelt and wheat bread in human volunteers

The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was similar to that of wheat bread. However, in order to avoid more inter-individual variability, our data supports the importance to propose standardised carbohydrate content for the last meal before evaluating the GI of food.     

Electrical and microstructural characterization of two-step sintered ceria-based electrolytes

Gadolinium-doped ceria-based materials with and without Ga-additions were prepared following several firing schedules including one peak sintering temperature (up to 1300 °C) with or without subsequent dwell at lower temperature (at 1150 °C). Sintered disks with submicrometric grain size and densifications in the order of 92% or higher, were obtained in this manner, with the final result depending slightly on the sintering profile and presence of Ga as dopant. All materials were characterized by scanning electron microscopy, X-ray diffraction and impedance spectroscopy in air, in the temperature range 200–800 °C. The grain boundary arcs were found slightly dependent on grain size and porosity but significantly on Ga-doping, due to the likely presence of large concentrations of Ga along the grain boundary region.     

Business-Driven Design of Infrastructures for IT Services

A methodology for designing data center infrastructure for Information Technology (IT) services is developed. The main departure from existing methodologies is that it evaluates and compares alternative designs using business metrics rather than purely technical metrics. Specifically, the methodology evaluates the business impact (financial loss) imposed by imperfect infrastructure. The methodology provides the optimal infrastructure that minimizes the sum of provisioning costs and business losses incurred during failures and performance degradations. Several full numerical example scenarios are provided and results are analyzed. The use of the method for dynamically provisioning an adaptive infrastructure is briefly discussed.     

Essential elements and contaminants in edible tissues of European and American lobsters

In several European countries clawed lobsters, such as the European (Homarus gammarus) and American (H. americanus) ones are widely consumed. Yet, information about essential elements and contaminants in both species is still scarce. Therefore, the aim of this work was to characterise the elemental content in the edible part (muscle, hepatopancreas, gonads and roe) of both homarids and to compare them with the daily intake recommendations and maximum allowed levels. Two techniques were employed: energy-dispersive X-ray fluorescence (EDXRF) to quantify Cl, S, K, Ca, Fe, Cu, Zn, As, Se, Br and Sr; and flame atomic-absorption spectrometry (FAAS) to analyse Na, Mg, Mn, Cd, Hg and Pb. Significant differences were found in the elemental composition of edible tissues of both species, likely reflecting the distinct physiological role of those tissues: muscle (higher: Na, Mg, Ca and Sr; lower: Fe, Se, Cd); hepatopancreas (higher: Fe, Cu, Br and Cd); gonads (lower: Cl, Ca, Zn and Hg); and roe (higher: Na and Br; lower: K and As). Statistical differences in the elemental composition of each tissue were found between both homarids: Muscle (Na, Se, As and Hg); Hepatopancreas (Na, Mg, Fe, Cu, Se, Br and Hg); and gonads (S and Zn). Since the geographical distribution of both species is different, the differences likely reflect distinct elemental composition in the aquatic environment and, consequently in the feed chain. Both lobster species were rich sources of Na, Cl, Cu, Zn and Se for human consumption. Regarding contaminants, only Cd was detected at high concentrations in the hepatopancreas of both homarids. Despite Cd values were well above the maximum allowed level set by the European Commission for crustaceans’ muscle, so far any limit value was set for crustaceans’ hepatopancreas. Nonetheless, the present study recommends avoiding or moderately consuming this tissue in homarids.