Effect of heavy interstitials on anelastic properties of Nb-1.0 wt% Zr alloys

The mechanical properties of metals with bcc structure, such as niobium and its alloys, have changed significantly with the introduction of heavy interstitial elements. These interstitial elements (nitrogen, for example), present in the alloy, occupy octahedral sites and constitute an elastic dipole of tetragonal symmetry and might produce anelastic relaxation. This article presents the effect of nitrogen on the anelastic properties of Nb-1.0 wt% Zr alloys, measured by means of mechanical spectroscopy using a torsion pendulum. The results showed complex anelastic relaxation structures, which were resolved into their constituent peaks, representing each relaxation process. These processes are due to stress-induced ordering of the interstitial elements around the niobium and zirconium of the alloy.

O programa Saúde da Família pelo olhar do Cirurgião-Dentista

This study tried to know the social representation of dentists surgeons about the Family Health Program (FHP). Where used as methodological instruments a semi-structured interview and direct observation of work process in tive towns that are part of the metropolis region ofNatal city. During the interview some aspects where broached, such as the reasons of dentists surgeons join the FHP, what are the implications ofthe introduction of this program in the everyday practice, what kind of activities are they practicing and what are those professional missing the most in the FHP. In the direct observation where take in account some aspects related to the physic structure of health units, its service organization and demand, relationship amongst dentist and other member of the team, and about patient receptiveness, when they arrives at health unit. This study also identifY the researches subject showing their age, sex, for how they are graduates, what are them specialty and for how long they work for the FHP. The data had been analyzed through the analysis of content of Bardin5. The dentists depict the FHP for the change in assistance model through the preventive proposal of social work that makes possible to work with an ample concept of health. However what makes the FHP more attractive to dentists is the salary questiono The creation of bonds whit the community and the work whit groups and in team had been the main occurred changes in the daily one of the pratices ones of these professionals. The principal activities executed for these professionals inside of the new strategy of assistance in oral health are the carried trough preventive activities achieved in health units and social area. To them, the absence of institutional support and the employment of only one dentist for each team it is one the main point of strangling. There is no doubt that FHP is new strategy and that it is need a better integration amongst the professional, the institution

Neurofisiologia hipocampal durante sessões de sono intercaladas por exploração espacial: Reverberação do passado ou predição do futuro?

The ability to predict future rewards or threats is crucial for survival. Recent studies have addressed future event prediction by the hippocampus. Hippocampal neurons exhibit robust selectivity for spatial location. Thus, the activity of hippocampal neurons represents a cognitive map of space during navigation as well as during planning and recall. Spatial selectivity allows the hippocampus to be involved in the formation of spatial and episodic memories, including the sequential ordering of events. On the other hand, the discovery of reverberatory activity in multiple forebrain areas during slow wave and REM sleep underscored the role of sleep on the consolidation of recently acquired memory traces. To this date, there are no studies addressing whether neuronal activity in the hippocampus during sleep can predict regular environmental shifts. The aim of the present study was to investigate the activity of neuronal populations in the hippocampus during sleep sessions intercalated by spatial exploration periods, in which the location of reward changed in a predictable way. To this end, we performed the chronic implantation of 32-channel multielectrode arrays in the CA1 regions of the hippocampus in three male rats of the Wistar strain. In order to activate different neuronal subgroups at each cycle of the task, we exposed the animals to four spatial exploration sessions in a 4-arm elevated maze in which reward was delivered in a single arm per session. Reward location changed regularly at every session in a clockwise manner, traversing all the arms at the end of the daily recordings. Animals were recorded from 2-12 consecutive days. During spatial exploration of the 4-arm elevated maze, 67,5% of the recorded neurons showed firing rate differences across the maze arms. Furthermore, an average of 42% of the neurons showed increased correlation (R>0.3) between neuronal pairs in each arm. This allowed us to sort representative neuronal subgroups for each maze arm, and to analyze the activity of these subgroups across sleep sessions. We found that neuronal subgroups sorted by firing rate differences during spatial exploration sustained these differences across sleep sessions. This was not the case with neuronal subgroups sorted according to synchrony (correlation). In addition, the correlation levels between sleep sessions and waking patterns sampled in each arm were larger for the entire population of neurons than for the rate or synchrony subgroups. Neuronal activity during sleep of the entire neuronal population or subgroups did not show different correlations among the four arm mazes. On the other hand, we verified that neuronal activity during pre-exploration sleep sessions was significantly more similar to the activity patterns of the target arm than neuronal activity during pre-exploration sleep sessions. In other words, neuronal activity during sleep that precedes the task reflects more strongly the location of reward than neuronal activity during sleep that follows the task. Our results suggest that neuronal activity during sleep can predict regular environmental changes

Two-dimensional position-dependent massive particles in the presence of magnetic fields

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Beam Search Algorithms for Minimizing Tool Switches on a Flexible Manufacturing System

In the minimization of tool switches problem we seek a sequence to process a set of jobs so that the number of tool switches required is minimized. In this work different variations of a heuristic based on partial ordered job sequences are implemented and evaluated. All variations adopt a depth first strategy of the enumeration tree. The computational test results indicate that good results can be obtained by a variation which keeps the best three branches at each node of the enumeration tree, and randomly choose, among all active nodes, the next node to branch when backtracking.

Micro Welding of Ni-based Alloy Monel 400 Thin Foil by Pulsed Nd:YAG laser

In this study a pulsed Nd:YAG laser was used to join Monel 400 thin foil with 100 mu m thickness. Pulse energy was varied from 1.0 to 2.25J at small increments of 0.25J. The macro and microstructures were analyzed by optical microscopy, tensile shear test and microhardness. Sound laser welds without discontinuities were obtained with 1.5 J pulse energy. Results indicate that using a precise control of the pulse energy, and so a control of the bottom foil dilution rate, it is possible to weld Monel 400 thin foil. The process appeared to be very sensitive to the gap between couples.

Pulsed Nd:YAG laser welding of Ni-alloy Hastelloy C-276 foils

In this study a pulsed Nd:YAG laser was used to join Hastelloy C-276 thin foil with 100 microns thickness. Pulse energy was varied from 1.0 to 2.25 J at small increments of 0.25 J with a 4 ms pulse duration. The macro and microstructures of the welds were analyzed by optical and electronic microscopy, tensile shear test and microhardness. Sound laser welds without discontinuities were obtained with 1.5 J pulse energy. Results indicate that using a precise control of the pulse energy, and so a control of the dilution rate, it is possible to weld Hastelloy C-276 thin foil by pulsed Nd: YAG laser. (C) 2012 Published by Elsevier B. V. Selection and/or review under responsibility of Bayerisches Laserzentrum GmbH

Síntese, caracterização e aplicação de MCM-41 funcionalizado com diisopropilamina no processo de adsorção do dióxido de carbono

Emissions of CO2 in the atmosphere have increased successively by various mechanisms caused by human action, especially as fossil fuel combustion and industrial chemical processes. This leads to the increase in average temperature in the atmosphere, which we call global warming. The search for new technologies to minimize environmental impacts arising from this phenomenon has been investigated. The capture of CO2 is one of the alternatives that can help reduce emis ions of greenhouse gases. The CO2 can be captured through the process of selective adsorption using adsorbents for this purpose. Were synthesized by hydrothermal method, materials of the type MCM-41 and Al-MCM-41 in the molar ratio Si / Al equal to 50. The synthesis of gels were prepared from a source of silicon, sodium, water and aluminum in the case of Al-MCM-41. The period of synthesis of the materials was 5 days in autoclave at 100°C. After that time materials were filtered, washed and dried in greenhouse at 100 º C for 4 hours and then calcined at 450 º C. Then the calcined material was functionalized with the Di-isopropylamine (DIPA) by the method of wet impregnation. We used 0.5 g of material mesopores to 3.5 mL of DIPA. The materials were functionalized in a closed container for 24 hours, and after this period were dried at brackground temperature for 2 hours. Were subsequently subjected to heat treatment at 250°C for 1 hour. These materials were used for the adsorption of CO2 and were characterized by XRD, FT-IR, BET / BJH, SEM, EDX and TG / DTG. Tests of adsorption of CO2 was carried out under the following conditions: 100 mg of adsorbent, temperature of 75°C under flow of 100 mL/min of CO2 for 2 hours. The desorption of CO2 was carried out by thermogravimetry from ambient temperature to 900ºC under flow of 25 mL min of He and a ratio of 10ºC/min. The difratogramas X-ray for the synthesized samples showed the characteristic peaks of MCM-41, showing that the structure of it was obtained. For samples functionalized there was a decrease of the intensities of these peaks, with a consequent reduction in the structural ordering of the material. However, the structure was preserved mesopores. The adsorption tests showed that the functionalized MCM-41 is presented as a material promising adsorbent, for CO2 capture, with a loss of mass on the desorption CO2 of 7,52%, while that in Al-MCM- 41 functionalized showed no such loss

Influência da acrilamida e da poliacrilamida em sistema microemulsionado visando aplicação na recuperação avançada de petróleo

This work aims to study the influence of two additives, the monomer, acrylamide and its polymer, polyacrylamide, solubilized in microemulsion systems and applied on enhanced oil recovery. By the microemulsion system obtained, it was chosen points into the phase diagram, presenting these compositions: 25%, 30%, 35% C/T; 2% Fo (fixed for all points) e 73%, 68% e 63% Fa, respectively. However, the monomer and the polymer were solubilized in these microemulsion points with 0.1%; 0.5%; 1% e 2% of concentration, ordering to check the concentration influence at the physicochemical properties (surface tension and rheology) of the microemulsion. Through the salinity study, was possible to observe that the concentrations of 1% and 2% of polymer made the solution became blurred, accordingly, the study of surface tension and rheology only was made for the concentrations of 0.1% e 0.5% of monomer and polymer, respectively. By the surface tension study it was observed that how the concentration of active matter (C/T) was increasing the surface tension was amending for each system, with or without additives. In the rheology study, as it increases the concentration of active matter increases both the viscosity of the microemulsion system (SME) with no additive, as the SME with polymer (AD2). After the entire study, it was chosen the lower point of active matter (25% C/T; 2% Fo e 73% Fa), plus additives in concentrations of 0.1% and 0.5% to be used on enhanced oil recovery. Assays were made on sandstone from Botucatu Formation, where after the tests, it was concluded that among the studied points, the point who showed the best efficiency of advanced shift was the microemulsion system + 0.5% AD2, with a recovery of 28% of oil in place and a total of 96,49%, while the other solution with 0.5% of polymer presented the worst result, with 14.1% of oil in place and 67,39% of efficiency of total displacement

Síntese, caracterizaçao e propriedades catalicas da peneira molecular nanoestruturada modificada com lantanio

The nanostructured molecular sieve SBA-15 was synthesized by the hydrothermal method, and modified with lanthanum with Si/La molar ratios of 25, 50, 75 and 100. The materials were evaluated as catalysts for the cracking of n-hexane model reaction. Type SBA- 15 and LaSBA-15 mesoporous materials were synthesized using tetraetilortosilicato as a source of silica, hydrochloric acid, heptahydrate lanthanum chloride and distilled water. Pluronic P123 triblock. polymer was used as structure template. The syntheses were carried out by 72 hours. The obtained SBA-15 samples were previously analyzed by thermogravimetry, in order to check the conditions of calcination for removal of organic template. Then, the calcined materials were characterized by X-ray diffraction, infrared spectroscopy, adsorption and desorption of nitrogen, scanning electron microscopy and X-ray microanalysis by dispersive energy. The acidity of the samples was determined using adsorption of n-bulinamina and desorption followed by thermogravimetry. It was found that the hydrothermal synthesis method was suitable for the synthesis of the SBA-15 mesoporous materials, with an excellent degree of hexagonal ordering. The reactions of catalytic cracking of n-hexane were carried out using a fixed bed continuous flow microreactor, coupled on-line to a gas chromatograph. From the catalytic evaluation, it was observed that the mesoporous materials containing lanthanum showed different results for the reaction of cracking of nhexane compared to the unmodified mesoporous material SBA-15. As a result of cracking was obtained as main products hydrocarbons in the range of C1 to C5. The catalyst that showed better properties in relation to the acidity and catalytic activity was LaSBA-15 with the ratio Si/La = 50

As Faces e os Disfaces da Informalidade no Capitalismo Conteporâneo: Um Estudo do Comércio de Rua em Pau dos Ferros/RN

This paper discusses the expression of informality in contemporary capitalism. Thematic of relevance to the analysis of the reality of work today and the logic that moves the capital, its real presence in the lives of individuals. The street trading of Pau dos Ferros town, popularly known as "street market" was chosen as the search space. The main objective is to seize and examine the articulations and logic, present in the configuration of the street trading of this city, located in the state of Rio Grande do Norte, explaining the functionality of informality for capitalist accumulation, but also for the reproduction of segments of the working class. Our analysis is based in the perspective of totality, trying to grasp the historical determinations of the phenomenon in focus. It includes the analysis of the mechanisms used by the capital to reproduce itself in the current historical context, which has been implicated in the composition of the labor markets of different countries and in various forms of exploitation to which workers in general are subject. It also means discussing the development of capitalism in Brazil, the logic that permeates its dependence, and especially the use of over-exploitation of labor, as a lever for internal accumulation. The course of investigation consisted of theoretical research to form the basis of theoretical and methodological analysis and to outline the context in which our research object is inserted, and field research conducted in two phases: systematic observation, which allowed to map traders features and the infrastructure of commerce, and the conduction of interviews with key informants. The material collected was scrutinized according to analytical scheme inspired by the content analysis. Among the main considerations developed from the research process we include: the street trading of Pau dos Ferros remains shrouded in the majority sale of agricultural products, this demonstrates the structural characteristics of the region. However, the supply of this product is no longer restricted to the excess of small local producers. The presence of the dealer changed the distribution of the product, streamlining it. In parallel, business practices are developed, practices in which traded goods (industrial) reflect the moment of capitalist restoration, a larger business network. The reflections also made it possible to show that street trading follows developing on the basis of informal work, which gains functionality to the system, as it is configured as a space commonly used to drain part of the production, of industries (clothing/shoes), especially if the distribution is considered as an essential element of the complex process that aims at capital appreciation. This activity has been functioning as a place of employment and income generation for the subjects who are away from formal employment, masking, this way, unemployment, moreover, they allow them to continue as consumers. Such expressions reflect the ability and the logic of capital to expand and aggregate into so many realities. It is underway today, the logic that has led many workers to join the project of domination of capital, by the illusory chance to become capitalists. The aim has been to turn the subject into a consumer and the worker an enterprising

O Serviço social nas organizações não-governamentais: tendências e particularidades

The present study is about the professional exercise of the Social Worker in ONGs associated with the ABONG in Natal city, state of Rio Grande do Norte, referring to the work conditions, claims and professional responses in front of the capital restructuration circumstances. The group of socio-historical transformations, as a result of the after-1970 dynamic capitalism, conducts a process of new configurations in the relationship between State and society that directly affect the social question nowadays, destroying social rights historically conquered for the workers. In this context, the ONGs assume a strategical social function of the social question, contributing with the change of responsibilities with the social from the State to the third sector. This social movement causes changes to the Social Work since this is one of the professions that act on the immediate expressions of the social question. After a qualitative research based on a theoricalmethodological critical and dialectical perspective, it was possible to discover some contradictions, details and tendencies of the professional exercise of the Social Worker in ONGs. Summarizing, the results of the research show that: a) it was detected a tendency of precarization, instability, insecurity, no-articulation, no-profissionalization of the professionals in the work conditions; b) demands are associated with a moment of the capital re-ordering, where new professional exigencies and responsibilities are related with capital necessities in the period of structural crisis; c) limits and contradictions are present in a professional daily work mainly in function of the characteristics of gestation and functioning of the ONGs; d) the professionals that were interviewed show significant difficulties in a articulation between the professional daily work in organizations and the totality of the social processes, limiting the capability of doing critics to the requisitions imposed by the capital

Zoneamento geoambiental como subsídio ao planejamento territorial municipal: estudo de caso para Currais Novos/RN

This paper presents the master plan and geoenvironmental zoning natures as instruments of environmental planning and management. The discussion of territory environmental planning is guided by two directions: at first the environmental elements involved in planning and the another is the implementation of these instruments at the municipal territory. To analyze the planning directed of the municipal territory we consider the fragments of its, represented by country and urban. The master plan inside of the Estatuto da Cidade (City Statute) and the geoenvironmental zoning are directed to territorial environmental planning. Regarding of the master plan the first challenge has been the spacial area that the plan can cover. It is necessary to prepare master plans that could include all the territory. The environmental zoning are directed for the territory totality.In this sense, the geoenvironmental zoning of the Currais Novos was done in the totality of the municipal territory and guided by the environmental physics variables. The geoenvironmental zoning sets in a planning and ordering of the territory instrument based in the landscape analysis. Therefore grounded in the Geosystems‟s Theory this work has like a main objective to propose a geoenvironmental zoning for the Currais Novos Municipality in RN. So, was used an analysis technique suggested for Bardin (2010) and the Currais Novos‟s physical environment characterization through of the fieldwork and cartographic data vectorization, beyond the image‟s treatment SRTM. The geoenvironmental systems definitions were based in the suggestion of Cestaro, et al. (2007) support in Bertrand (1968). For both were identified five geoenvironmental systems: Borborema Plateau, Residual plateau, Chapada da Serra de Santana, semiarid river valley and lagoon valley and eleven geoenvironmental subsystems: Borborema Plateau Western Slope, Isolated Massif of the Borborema Plateau, Residual Crest, Residual Massif, Erosional Scarp of the Chapada, flat top plateau, fluvial plains, temporary river of the semiarid and ornamental water or sluice

Propriedades magnéticas de ortoferritas de lantânio dopadas com estrôncio

Samples of lanthanum Ortoferrites doped with strontium were synthesized in a single phase by the sol-gel method. Two samples were prepared, one by varying the concentration of strontium in lanthanum ortoferrites La1−xSrxFeO3−δ with (0 ≤ x ≤ 0.5), and another batch of samples of type, La1/3Sr2/3FeO3−δ, now varying only the temperature of calcination. Our samples were obtained by Pechini method and sintered in air and oxygen atmospheric. Their crystal structures were determined by x-ray diraction (XRD), scanning electron microscopy (SEM), where we observed that the samples (0 ≤ x ≤ 0.3) have orthorhombic symmetry and the volume of the single cell decreases with the increasing of concentration of strontium. For x = 0.5 it is only observed the simple phase when that is sintered in O2 atmospheric. Their magnetic characteristics were obtained by the Mössbauer spectroscopy and magnetic measurements. The magnetization measurements for samples La1−xSrxFeO3−δ with (0 ≤ x ≤ 0.5) revealed that the magnetization decreases with increasing concentration of strontium, but for the sample x = 0.4 the magnetization shows a high coercive field and a ferrimagnetic behavior, which is attributed to a small amount of strontium hexaferrite. As for the samples La1/3Sr2/3FeO3−δ calcined between 800 oC e 1200 oC. The hysteresis curves revealed two distinct behaviors: an declined antiferromagnetic behavior (Canted) for samples calcined between 800 oC and 1000 oC and a paramagnetic behavior for the samples calcined at 1100 oC e 1200 o C. Thermal hysteresis and sharp peaks around the Néel temperature (TN), over the curves of specific heat as a function of temperature was only observed in calcined samples with 1100 oC and 1200 oC. This eect is attributed to the charge ordering. These results indicate that the charge ordering occurs only in the samples without oxygen deficiency. Magnetic measurements as a function of temperature are also in agreement with this interpretation

Modelagem de vulnerabilidade de sistemas ambientais no municípo de Guadalupe/PI

In the Guadalupe city, with the arrival of the Boa Esperança Hydroelectric, the landscape of the municipal district lived important transformations. Those transformations continue growing today, now together with new vectors of territorial ordering, especially the agricultural industry. In front of the context of stability-instability of the environmental systems, it original of its natural vulnerability to the instability and of the transformations in the territorial dynamics of Guadalupe, the present research it analyzed and it mapped that municipal territory with relationship to the degrees of vulnerability of the environmental systems. Therefore, working a leaning methodology in a systemic perspective of the landscape and in the geoprocessing technique, the dissertation showed with thematic mapping, the most vulnerable and less vulnerable parts of the municipal district of Guadalupe, looking for a strategic vision of the problem.