Thermodynamic analysis of direct steam reforming of ethanol in molten carbonate fuel cell

Fuel cell as MCFC (molten carbonate fuel cell) operate at high temperatures, and due to this issue, cogeneration processes may be performed, sending heat for own process or other purposes as steam generation in an industry. The use of ethanol for this purpose is one of the best options because this is a renewable and less environmentally offensive fuel, and cheaper than oil-derived hydrocarbons (in the case of Brazil). In the same country, because of technical, environmental and economic advantages, the use of ethanol by steam reforming process have been the most investigated process. The objective of this study is to show a thermodynamic analysis of steam reforming of ethanol, to determine the best thermodynamic conditions where are produced the highest volumes of products, making possible a higher production of energy, that is, a most-efficient use of resources. To attain this objective, mass and energy balances are performed. Equilibrium constants and advance degrees are calculated to get the best thermodynamic conditions to attain higher reforming efficiency and, hence, higher electric efficiency, using the Nernst equation. The advance degree of reforming increases when the operation temperature also increases and when the operation pressure decreases. But at atmospheric pressure (1 atm), the advance degree tends to the stability in temperatures above 700°C, that is, the volume of supplemental production of reforming products is very small for the high use of energy resources necessary. Reactants and products of the steam-reforming of ethanol that weren't used may be used for the reforming. The use of non-used ethanol is also suggested for heating of reactants before reforming. The results show the behavior of MCFC. The current density, at same tension, is higher at 700°C than other studied temperatures as 600 and 650°C. This fact occurs due to smaller use of hydrogen at lower temperatures that varies between 46.8 and 58.9% in temperatures between 600 and 700°C. The higher calculated current density is 280 mA/cm 2. The power density increases when the volume of ethanol to be used also increases due to higher production of hydrogen. The highest produced power at 190 mW/cm 2 is 99.8, 109.8 and 113.7 mW/cm2 for 873, 923 and 973K, respectively. The thermodynamic efficiency has the objective to show the connection among operational conditions and energetic factors, which are some parameters that describes a process of internal steam reforming of ethanol.

Characteristics of the double-torsion test to determine the R-curve of ceramic materials

Double-torsion tests were carried out on a commercial ceramic floor tile to verify whether this test is suitable for determining the R-curve of ceramics. The instantaneous crack length was obtained by means of compliance calibration, and it was found that the experimental compliance underestimates the real crack length. The load vs. displacement curves were also found to drop after maximum loading, causing the stress intensity factor to decline. The R-curves were calculated by two methods: linear elastic fracture mechanics and the energetic method. It was obtained that the average values of crack resistance, R, and the double of the work of fracture, 2 · γwof, did not depend on notch length, a0, which is a highly relevant finding, indicating that these parameters were less dependent on the test specimen's geometry. The proposal was to use small notches, which produce long stable crack propagation paths that in turn are particularly important in the case of coarse microstructures.

Strain relaxation and stress-driven interdiffusion in InAsInGaAsInP nanowires

The authors have investigated strain relaxation in InAsInGaAsInP nanowires (NW's). Transmission electron microscopy images show an additional stress field attributed to compositional modulation in the ternary layer, which disrupts NW formation and drives Ga interdiffusion into InAs, according to grazing incidence x-Ray diffraction under anomalous scattering conditions. The strain profile along the NW, however, is not significantly affected when interdiffusion is considered. Results show that the InAs NW energetic stability is preserved with the introduction of ternary buffer layer in the structure. © 2007 American Institute of Physics.

Abnormal evening vertical plasma drift and effects on ESF and EIA over Brazil-South Atlantic sector during the 30 October 2003 superstorm

Equatorial F region vertical plasma drifts, spread F and anomaly responses, in the south American longitude sector during the superstorm of 30 October 2003, are analyzed using data from an array of instruments consisting of Digisondes, a VHF radar, GPS TEC and scintillation receivers in Brazil, and a Digisonde and a magnetometer in Jicamarca, Peru. Prompt penetrating eastward electric field of abnormally large intensity drove the F layer plasma up at a velocity ∼1200 ms -1 during post dusk hours in the eastern sector over Brazil. The equatorial anomaly was intensified and expanded poleward while the development of spread F/plasma bubble irregularities and GPS signal scintillations were weaker than their quiet time intensity. Significantly weaker F region response over Jicamarca presented a striking difference in the intensity of prompt penetration electric field between Peru and eastern longitudes of Brazil. The enhanced post dusk sector vertical drift over Brazil is attributed to electro-dynamics effects arising energetic particle precipitation in the South Atlantic Magnetic Anomaly (SAMA). These extraordinary results and their longitudinal differences are presented and discussed in this paper. Copyright 2008 by the American Geophysical Union.

Utilization of neuromuscular electrical stimulation in the acute phase of ankle immobilization at 90°: Study in rats

Objective: To evaluate the skeletal muscle glycogen content and plasmatic concentration of interleukin -6 (IL-6), interleukin-4 (IL-4), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α) in rats submitted to electrical stimulation sessions during the first three days of ankle immobilization at the position of 90°. Methods: Albinomale Wistar rats(3-4 months) were maintained in vivarium. conditions with food and water ad libitum, Submitted to 12 h photoperiodic cycles of light/dark, and distributed into 7 experimental groups (n = 6): control(C), immobilized 1 day(I1) immobilized 1 day and electrically stimulated(IE1) immobilized 2 days(12), immobilized 2 days and electrically stimulated(IE2), immobilized 3 days(13) and immobilized 3 days and electrically stimulated(IE3). Groups I utilized an acrylic resin orthesis model and groups electrically stimulated (IE) utilized the orthesis and a session of electrotherapy by a Dualpex 961 (biphasic quadratic pulse, 10 Hz, 0.4 ms, 5.0 mA, one 20 min session a day). After the experimental period, the rats were anesthetized with pentobarbital sodium(40 mg/kg) and a blood sample was colleted to evaluate the plasmatic concentration of interleukins by means of the radioimmunoassay method. The soleus and the white portion of the gastrocnemius muscle were colleted for glycogen reserves analysis(GLY). Other groups of rats were used to apply the glucose tolerance test(GTT) and insulin tolerance test(ITT). For statistical analysis, the Kolmogorov-Smirnov normality test followed by ANOVA and the Tukey tests were utilized, with a critical level established at 5%. Results: In ITT test, groups IE enhanced the skeletal muscle glucose uptake, but no changes were observed in GTT after the therapy session, which indicates that electrical stimulation is a sensibilizing method to augment skeletal muscle glucose uptake. The GLY reserves were reduced in I groups, which indicate that disuse altered insulin sensitivity and compromised energetic homeostasis. However. the IE groups displayed an augment in GLY content, suggesting that electrical stimulation restores the enzymatic pathways altered by immobilization. The improvement in GLY was accompanied by an elevation of the plasmatic concentration of IL-6 and TNF-α, showing the participation of these interleukins in the control of metabolic profile. Plasmatic concentrations of IL-10 were elevated only after 3 days of IE while IL-4 did not display any modifications. Conclusion: The results suggest that neuromuscular electricaf stimulation is an important toot in the maintenance of energetic, conditions of musculature submitted to immobilization, and presents multifactor mechanisms linked to interleukins action that converge to maintain the energetic equilibrium of the tissue in disuse.

Running behavior and its energy cost in mice selectively bred for high voluntary locomotor activity

Locomotion is central to behavior and intrinsic to many fitnesscritical activities (e.g., migration, foraging), and it competes with other life-history components for energy. However, detailed analyses of how changes in locomotor activity and running behavior affect energy budgets are scarce. We quantified these effects in four replicate lines of house mice that have been selectively bred for high voluntary wheel running (S lines) and in their four nonselected control lines (C lines). We monitored wheel speeds and oxygen consumption for 24-48 h to determine daily energy expenditure (DEE), resting metabolic rate (RMR), locomotor costs, and running behavior (bout characteristics). Daily running distances increased roughly 50%-90% in S lines in response to selection. After we controlled for body mass effects, selection resulted in a 23% increase in DEE in males and a 6% increase in females. Total activity costs (DEE - RMR) accounted for 50%-60% of DEE in both S and C lines and were 29% higher in S males and 5% higher in S females compared with their C counterparts. Energetic costs of increased daily running distances differed between sexes because S females evolved higher running distances by running faster with little change in time spent running, while S males also spent 40% more time running than C males. This increase in time spent running impinged on high energy costs because the majority of running costs stemmed from postural costs (the difference between RMR and the zero-speed intercept of the speed vs. metabolic rate relationship). No statistical differences in these traits were detected between S and C females, suggesting that large changes in locomotor behavior do not necessarily effect overall energy budgets. Running behavior also differed between sexes: within S lines, males ran with more but shorter bouts than females. Our results indicate that selection effects on energy budgets can differ dramatically between sexes and that energetic constraints in S males might partly explain the apparent selection limit for wheel running observed for over 15 generations. © 2009 by The University of Chicago. All rights reserved.

Grupo itararé (P - C da bacia do Paraná) nas regiões de Limeira e Piracicaba - SP: Contribuição ao estudo das litofácies

The Permian-Carboniferous Itararé Group is one complexe lithostratigraphic unit of the Paraná Basin, southeastern Brazil, typically marked by discontinuity of its lithofacies. Under the exploratory point of view, the unit represents one of the most significant intervals of the basin, since several occurrences of mineral and energetic resources are associated to it, as groundwater, petroleum and coal. The prospection and exploitation of these resources depend on a good understanding of the stratigraphic architecture and the paleogeography. There are many contributions on the specialized literature which deal with this subject, although the regions of Limeira and Piracicaba (superior portion of the unit) still lack new investigations, which may contribute to the understanding of its lithofacies and related sedimentary processes. It was analyzed the sedimentary sets pilling up, followed by stratigraphic correlations between the two regions. Moreover, from sedimentary structures, it was made paleocurrent measurement with the purpose of obtaining indicative patterns of the sedimentary polarity, contributing for the comprehension of the paleogeography. Recent studies in the Domo de Pitanga region (between Rio Claro and Piracicaba cities) and in the Corumbataí river drainage basin, were taken also as basis for possible correlations. It was obtained a frame of the lithofacies arrangement, their vertical and lateral relations, as well as their depositional polarities.

Multilateral rules on competition policy: an overview of the debate

Includes bibliography

Search for supersymmetry in pp collisions at √s = 7 TeV in events with a single lepton, jets, and missing transverse momentum

Results are reported from a search for physics beyond the standard model in proton-proton collisions at a center-of-mass energy of 7TeV, focusing on the signature with a single, isolated, high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The data sample comprises an integrated luminosity of 36 pb-1, recorded by the CMS experiment at the LHC. The search is motivated by models of new physics, including supersymmetry. The observed event yields are consistent with standard model backgrounds predicted using control samples obtained from the data. The characteristics of the event sample are consistent with those expected for the production of tt̄ and W+jets events. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model.

Search for microscopic black holes in pp collisions at √ s = 7 TeV

A search for microscopic black holes in pp collisions at a center-of-mass energy of 7TeV is presented. The data sample corresponds to an integrated luminosity of 4.7 fb1 recorded by the CMS experiment at the LHC in 2011. Events with large total transverse energy have been analyzed for the presence of multiple energetic jets, leptons, and photons, which are typical signals of evaporating semiclassical and quantum black holes, and string balls. Agreement with the expected standard model backgrounds, which are dominated by QCD multijet production, has been observed for various combined multiplicities of jets and other reconstructed objects in the final state. Model-independent limits are set on new physics processes producing high-multiplicity, energetic final states. In addition, new model-specific indicative limits are set excluding semiclassical and quantum black holes with masses below 3.8 to 5.3TeV and string balls with masses below 4.6 to 4.8TeV . The analysis has a substantially increased sensitivity compared to previous searches.

Fontes energéticas associadas ao farelo de girassol ou à ureia em dietas para novilhos

The objective of this study was to evaluate the performance and carcass traits of steers fed corn or citrus pulp associated with sunflower meal or urea. Diets were composed of two energy sources (corn grain and citrus pulp) associated with two protein sources (soybean meal and urea), resulting in four treatments in forage:concentrate ratio of 40:60. It were used 24 steers, 1/2 Angus × 1/2 Nellore (18 months old and 329 kg BW) distributed in a completely randomized design which were finished in feedlot for 80 days. It were evaluated the intake, average daily gain and carcass traits of the animals. Intake of dry matter (DMI), crude protein (CPI) and neutral detergent fiber (NDFI) were affected (p<0.05) by diets. The diet with citrus pulp and urea (PU) showed the lowest (p<0.05) DMI (8.30 kg), CPI (1.03 kg) and NDFI (3.31 kg). The average daily weight gain (ADG) followed the behavior of DMI, NDFI and CPI and the lowest value (p<0.05) was observed for animals fed diet PU. Regarding carcass traits, diets containing corn associated with urea (MU) or sunflower meal (MFG) and citrus pulp associated with sunflower meal (PFG), provided the highest (p<0.05) carcass cold weights (238.37, 247.26 and 237.14 kg, respectively). However, the lowest cold carcass dressing percentage (p<0.05) was obtained in diet MU (50.57%). The association of citrus pulp with urea should not be performed when citrus pulp partially or totally replace corn as energy source in diets, because possibly this association promote an energy deficit resulting in lower performance and worse carcass traits of animals finished in feedlot.

Relationship between incubation temperature and egg size with heart hypoplasy in broiler chicks at hatching

It was analyzed if the effects of continuous incubation temperature deviations during the second half on the development of body, organs and hematological respiratory and energetic parameters differ between male and female from 30- and 60-week-old breeder eggs. From day 13, Cobb eggs were exposed to 36°C, 37.5°C, or 39°C. At 3, 6, 12, 24, 48 and 72 h after this change in the temperature and at hatch, red cells count, hematocrit, hemoglobin, mean corpuscular volume, plasma glucose level and body, liver and heart weights were evaluated. Independent of incubation temperature, sexes and breeder ages, mean corpuscular volume decreased and the other variables increased during late incubation. In 30-week-old breeder eggs, body weights and erythrocytic parameters were not influenced by temperature but liver and heart weights decreased increasing incubation temperature and glucose level increased at 36 and 39°C. In 60-week-old breeder eggs, males were heavier at hatching with incubation at 36°C and females had smaller body weights with incubation at 39°C. In both sexes, liver weight decreased and glucose concentration was higher at 36 and 39°C and heart weights and erythrocytes parameters were not influenced by temperature. Independent of breeder age, hatchability was lower at 39°C. The data show that high temperature from day 13 of incubation reduced more intensively the hatching success and caused cardiac hypoplasia in chicks from 30-week-old breeder eggs only, revealing for the first time that the susceptibility for ascites syndrome, by reduced heart development at hatching, is associated to a relationship between incubation temperature and egg size. © Asian Network for Scientific Information, 2012.

Search for supersymmetry in events with photons and low missing transverse energy in pp collisions at √s=7TeV

Many models of new physics, including versions of supersymmetry (SUSY), predict production of events with low missing transverse energy, electroweak gauge bosons, and many energetic final-state particles. The stealth SUSY model yields this signature while conserving R-parity by means of a new hidden sector in which SUSY is approximately conserved. The results of a general search for new physics, with no requirement on missing transverse energy, in events with two photons and four or more hadronic jets are reported. The study is based on a sample of proton-proton collisions at s=7TeV corresponding to 4.96fb-1 of integrated luminosity collected with the CMS detector in 2011. Based on good agreement between the data and the standard model expectation, the data are used to determine model-independent cross-section limits and a limit on the squark mass in the framework of stealth SUSY. With this first study of its kind, squark masses less than 1430 GeV are excluded at the 95% confidence level. © 2012 CERN.

Sustainable urban energy planning: The case study of a tropical city

The urbanization of modern societies has imposed to the planners and decision-makers a more precise attention to facts not considered before. Several aspects, such as the energy availability and the deleterious effect of pollution on the populations, must be considered in the policy decisions of cities urbanization. The current paradigm presents centralized power stations supplying a city, and a combination of technologies may compose the energy mix of a country, such as thermal power plants, hydroelectric plants, wind systems and solar-based systems, with their corresponding emission pattern. A goal programming multi-objective optimization model is presented for the electric expansion analysis of a tropical city, and also a case study for the city of Guaratinguetá, Brazil, considering a particular wind and solar radiation patterns established according to actual data and modeled via the time series analysis method. Scenarios are proposed and the results of single environmental objective, single economic objective and goal programming multi-objective modeling are discussed. The consequences of each dispatch decision, which considers pollutant emission exportation to the neighborhood or the need of supplementing electricity by purchasing it from the public electric power grid, are discussed. The results revealed energetic dispatch for the alternatives studied and the optimum environmental and economic solution was obtained. © 2012 Elsevier Ltd.

Measurement of the tt̄ production cross section in the τ+jets channel in pp collisions at √s = 7 TeV

The top-quark pair production cross section in 7 TeV center-of-mass energy proton-proton collisions is measured using data collected by the CMS detector at the LHC. The measurement uses events with one jet identified as a hadronically decaying τ lepton and at least four additional energetic jets, at least one of which is identified as coming from a b quark. The analyzed data sample corresponds to an integrated luminosity of 3.9 fb-1 recorded by a dedicated multijet plus hadronically decaying τ trigger. A neural network has been developed to separate the top-quark pairs from the W+jets and multijet backgrounds. The measured value of σtt̄= 152 ± 12,(stat.) ± 32,(syst.) ±,(lum.) pb is consistent with the standard model predictions. © 2013 CERN for the benefit of the CMS collaboration.