33 resultados para adjustable moment and rotation speed
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
This master thesis aims at developing a new methodology for thermochemical degradation of dry coconut fiber (dp = 0.25mm) using laboratory rotating cylinder reactor with the goal of producing bio-oil. The biomass was characterized by infrared spectroscopy with Fourier transform FTIR, thermogravimetric analysis TG, with evaluation of activation energy the in non-isothermal regime with heating rates of 5 and 10 °C/min, differential themogravimetric analysis DTG, sweeping electron microscopy SEM, higher heating value - HHV, immediate analysis such as evaluated all the amounts of its main constituents, i.e., lignin, cellulose and hemicelluloses. In the process, it was evaluated: reaction temperature (450, 500 and 550oC), carrier gas flow rate (50 and 100 cm³/min) and spin speed (20 and 25 Hz) to condensate the bio-oil. The feed rate of biomass (540 g/h), the rotation of the rotating cylinder (33.7 rpm) and reaction time (30 33 min) were constant. The phases obtained from the process of pyrolysis of dry coconut fiber were bio-oil, char and the gas phase non-condensed. A macroscopic mass balance was applied based on the weight of each phase to evaluate their yield. The highest yield of 20% was obtained from the following conditions: temperature of 500oC, inert gas flow of 100 cm³/min and spin speed of 20 Hz. In that condition, the yield in char was 24.3%, non-condensable gas phase was 37.6% and losses of approximately 22.6%. The following physicochemical properties: density, viscosity, pH, higher heating value, char content, FTIR and CHN analysis were evaluated. The sample obtained in the best operational condition was subjected to a qualitative chromatographic analysis aiming to know the constituents of the produced bio-oil, which were: phenol followed by sirigol, acetovanilona and vinyl guaiacol. The solid phase (char) was characterized through an immediate analysis (evaluation of moisture, volatiles, ashes and fixed carbon), higher heating value and FTIR. The non-condensing gas phase presented as main constituents CO2, CO and H2. The results were compared to the ones mentioned by the literature.
Resumo:
In machining of internal threads, dedicated tools, known as taps, are needed for each profile type, diameter, and low cutting speed values are used when compared to main machining processes. This restriction in the cutting speed is associated with the difficulty of synchronizing the tool s rotation speed and feed velocity in the process. This fact restricts the flexibility and makes machining lead times longer when manufacturing of components with threads is required. An alternative to the constraints imposed by the tap is the thread milling with helical interpolation technique. The technique is the fusion of two movements: rotation and helical interpolation. The tools may have different configurations: a single edge or multiple edges (axial, radial or both). However, thread milling with helical interpolation technique is relatively new and there are limited studies on the subject, a fact which promotes challenges to its wide application in the manufacturing shop floor. The objective of this research is determine the performance of different types of tools in the thread milling with helical interpolation technique using hardened steel workpieces. In this sense, four tool configurations were used for threading milling in AISI 4340 quenched and tempered steel (40 HRC). The results showed that climb cut promoted a greater number of machined threads, regardless of tool configuration. The upcut milling causes chippings in cutting edge, while the climb cutting promotes abrasive wear. Another important point is that increase in hole diameter by tool diameter ratio increases tool lifetime
Resumo:
This master thesis aims at developing a new methodology for thermochemical degradation of dry coconut fiber (dp = 0.25mm) using laboratory rotating cylinder reactor with the goal of producing bio-oil. The biomass was characterized by infrared spectroscopy with Fourier transform FTIR, thermogravimetric analysis TG, with evaluation of activation energy the in non-isothermal regime with heating rates of 5 and 10 °C/min, differential themogravimetric analysis DTG, sweeping electron microscopy SEM, higher heating value - HHV, immediate analysis such as evaluated all the amounts of its main constituents, i.e., lignin, cellulose and hemicelluloses. In the process, it was evaluated: reaction temperature (450, 500 and 550oC), carrier gas flow rate (50 and 100 cm³/min) and spin speed (20 and 25 Hz) to condensate the bio-oil. The feed rate of biomass (540 g/h), the rotation of the rotating cylinder (33.7 rpm) and reaction time (30 33 min) were constant. The phases obtained from the process of pyrolysis of dry coconut fiber were bio-oil, char and the gas phase non-condensed. A macroscopic mass balance was applied based on the weight of each phase to evaluate their yield. The highest yield of 20% was obtained from the following conditions: temperature of 500oC, inert gas flow of 100 cm³/min and spin speed of 20 Hz. In that condition, the yield in char was 24.3%, non-condensable gas phase was 37.6% and losses of approximately 22.6%. The following physicochemical properties: density, viscosity, pH, higher heating value, char content, FTIR and CHN analysis were evaluated. The sample obtained in the best operational condition was subjected to a qualitative chromatographic analysis aiming to know the constituents of the produced bio-oil, which were: phenol followed by sirigol, acetovanilona and vinyl guaiacol. The solid phase (char) was characterized through an immediate analysis (evaluation of moisture, volatiles, ashes and fixed carbon), higher heating value and FTIR. The non-condensing gas phase presented as main constituents CO2, CO and H2. The results were compared to the ones mentioned by the literature.
Resumo:
New technologies appear each moment and its use can result in countless benefits for that they directly use and for all the society as well. In this direction, the State also can use the technologies of the information and communication to improve the level of rendering of services to the citizens, to give more quality of life to the society and to optimize the public expense, centering it in the main necessities. For this, it has many research on politics of Electronic Government (e-Gov) and its main effect for the citizen and the society as a whole. This research studies the concept of Electronic Government and wishes to understand the process of implementation of Free Softwares in the agencies of the Direct Administration in the Rio Grande do Norte. Moreover, it deepens the analysis to identify if its implantation results in reduction of cost for the state treasury and intends to identify the Free Software participation in the Administration and the bases of the politics of Electronic Government in this State. Through qualitative interviews with technologies coordinators and managers in 3 State Secretaries it could be raised the ways that come being trod for the Government in order to endow the State with technological capacity. It was perceived that the Rio Grande do Norte still is an immature State in relation to practical of electronic government (e-Gov) and with Free Softwares, where few agencies have factual and viable initiatives in this area. It still lacks of a strategical definition of the paper of Technology and more investments in infrastructure of staff and equipment. One also observed advances as the creation of the normative agency, the CETIC (State Advice of Technology of the Information and Communication), the Managing Plan of Technology that provide a necessary diagnosis with the situation how much Technology in the State and considered diverse goals for the area, the accomplishment of a course of after-graduation for managers of Technology and the training in BrOffice (OppenOffice) for 1120 public servers
Resumo:
The assessment of building thermal performance is often carried out using HVAC energy consumption data, when available, or thermal comfort variables measurements, for free-running buildings. Both types of data can be determined by monitoring or computer simulation. The assessment based on thermal comfort variables is the most complex because it depends on the determination of the thermal comfort zone. For these reasons, this master thesis explores methods of building thermal performance assessment using variables of thermal comfort simulated by DesignBuilder software. The main objective is to contribute to the development of methods to support architectural decisions during the design process, and energy and sustainable rating systems. The research method consists on selecting thermal comfort methods, modeling them in electronic sheets with output charts developed to optimize the analyses, which are used to assess the simulation results of low cost house configurations. The house models consist in a base case, which are already built, and changes in thermal transmittance, absorptance, and shading. The simulation results are assessed using each thermal comfort method, to identify the sensitivity of them. The final results show the limitations of the methods, the importance of a method that considers thermal radiance and wind speed, and the contribution of the chart proposed
Resumo:
This study was intended to investigate how the urban form has been influencing the changes in the climate of the city and make a correlation between the climate and the thermal sensation of the users of open spaces. The research was developed in the district of Petrópolis in Natal/ RN whose occupation has been almost consolidated. Among other reasons, this district was selected because it was planned considering the environmental aspects of comfort. The methodologies used are based on KATZSCHNER (1997) and OLIVEIRA (1988) studies, which suggest the drawing and analysis of maps of the area under study, including topography, height of the buildings, land use, green areas, and types of soil pavement, as well as measurement of the environmental variables: air temperature, relative humidity, direction and wind speed for a comparative study. As part of this, study local users of the district were interviewed about their thermal sensations in open spaces. For the statistical analysis, data was collected at 10 distinct points characterized by BUSTOS ROMERO (2002), being 8 within the district and 2 at different places (outside the district), at climatologic stations, in 3 periods (August/2000, January/2002 and June/2002), for 4 consecutive days for each measurement (from Sunday to Wednesday) at the time of lower and higher temperatures in the city, 6:00 am and 1:00 pm, respectively. At the same time interviews were carried out with users of the open spaces in the area, totaling 171 valid formularies. The urban form showed a rather leveled topography, great diversity of land use and height of the buildings, with the existence of an area mostly occupied with high buildings, very little green area and soil practically impermeable. The statistical analysis showed high temperature and humidity levels. The wind direction is predominantly Southeast with extremely variable speeds. When the data from this district is compared with the data from other areas in the city and its outskirt, it was observed that this district is hotter and less ventilated than the others; besides, most users said that they felt uncomfortable in the local environmental conditions. The results of the analysis generated a zoning for the district with recommendations for soil occupation. The profile of the user was defined regarding the thermal comfort, as well as some discussion about the comfort parameters, including the proposal of limiting areas of temperature and humidity for the thermal comfort in the open spaces
Resumo:
The demand for alternative sources of energy drives the technological development so that many fuels and energy conversion processes before judged as inadequate or even non-viable, are now competing fuels and so-called traditional processes. Thus, biomass plays an important role and is considered one of the sources of renewable energy most important of our planet. Biomass accounts for 29.2% of all renewable energy sources. The share of biomass energy from Brazil in the OIE is 13.6%, well above the world average of participation. Various types of pyrolysis processes have been studied in recent years, highlighting the process of fast pyrolysis of biomass to obtain bio-oil. The continuous fast pyrolysis, the most investigated and improved are the fluidized bed and ablative, but is being studied and developed other types in order to obtain Bio-oil a better quality, higher productivity, lower energy consumption, increased stability and process reliability and lower production cost. The stability of the product bio-oil is fundamental to designing consumer devices such as burners, engines and turbines. This study was motivated to produce Bio-oil, through the conversion of plant biomass or the use of its industrial and agricultural waste, presenting an alternative proposal for thermochemical pyrolysis process, taking advantage of particle dynamics in the rotating bed that favors the right gas-solid contact and heat transfer and mass. The pyrolyser designed to operate in a continuous process, a feeder containing two stages, a divisive system of biomass integrated with a tab of coal fines and a system of condensing steam pyrolytic. The prototype has been tested with sawdust, using a complete experimental design on two levels to investigate the sensitivity of factors: the process temperature, gas flow drag and spin speed compared to the mass yield of bio-oil. The best result was obtained in the condition of 570 oC, 25 Hz and 200 cm3/min, temperature being the parameter of greatest significance. The mass balance of the elementary stages presented in the order of 20% and 37% liquid pyrolytic carbon. We determined the properties of liquid and solid products of pyrolysis as density, viscosity, pH, PCI, and the composition characterized by chemical analysis, revealing the composition and properties of a Bio-oil.
Resumo:
The study Escola e Gênero: representações de gênero na escola show us the social man made, starting of an analysis in the having fun time in the children´s life and how it´s an important aspect of the building childish universe simbolic. My analysis started in a children´s daily at school and how they noticed the play value od dominant society. Our propouse is think about the linking between ideology, representations and gender like the children´s knowledge in the school activities. The toy, an instrument which is noticed and exist in the funny activities, is full of cultural concepts of male and female parts. Your color, lines, functions and the way you manipulate is driven of gender cathegories. In the scool, the ideological concepts have it´s important way which is to domesticate the feelings, the desires; categorize and normalize them without be known by the educational employers. In the children´s education, the funny time is noticed by others ways and turned as important as others subjects. By the way it´s not noticed by the school, like another thing which isn´t a funny moment. And it´s exactly here in the school funny time, the school did your cultural power of separete the gender and your extencions, feed by the society, generaly, in favor of the man whose woman is your subordinate. This ways of analysis help the society and the school universe about the funny time e how they are important in the Man made life. And how the toys bring the concepts and addicted thinking, ideological which put the power in the stages, without equal, addicted feelings around the gender concepts. I read and used the theories of Kishimoto, Berger & luckmann, Brougère, Sousa Filho, Bourdieu, Badinter, Geertz, Grossi, Louro, Foucault, among others
Resumo:
Dormancy is an inherent property of the seeds that define the environmental conditions in which they are able to germinate and their presence is an adaptive trait common in species inhabiting semiarid regions. Moreover, the ability of seedling establishment in these environments has been related to the size, strength and chemical characteristics of the seeds. This study investigated patterns of dormancy and germination speed in tree species of the Caatinga, exploring how the seed size influence the processes of germination, seedling size and biomass allocation. In addition, we aim to investigate the chemical characteristics of the reserves, to verify a possible relationship between nutritional content and the process of seed germination. Therefore, seeds were collected from ten species of woody Caatinga for tests of breaking dormancy, germination and biochemical characterization. Overall, the results show that the scarification treatments mechanical and chemical, and thermal shock influenced the percentage and speed of germination in 50 % of the species, suggesting that they have some level of physical dormancy in the seeds. Biochemical characterization showed the existence of large amounts of carbohydrates in the seeds of all species, low proportion of protein and low amounts of neutral lipids. Using linear regression, we demonstrated the existence of a significant relationship between seed size and the ratio of root/shoot where the largest seeds invested a greater amount of resources for shoot growth. The relationship between germination speed and non-reducing sugar content was also significant, so these compounds is related to the maintenance of physiological seed quality. These results confirm some relationships discussed in the literature for cultivated species, but can be applied to the species native to the Caatinga
Resumo:
This research work worries in building the history of the natalense priest Miguel Joaquim of Almeida Castro, Miguelinho, I don't just eat one of the heroes and martyrs of the Revolution From Pernambuco of 1817, as bill the traditional history, but also the educated man, the intellectual and the admired teacher. The studied period understands the beginning of the century XIX, when priest Miguelinho comes back to Brazil, coming of Portugal, to assume teacher's occupation in the Seminar of Olinda, and it ends in the year of 1817, marked by the Revolution From Pernambuco, one of the most important movements in the fight for the liberation of Brazil of the Portuguese domain. Miguelinho, one of the leaders of the Revolution, that also reached the provinces of Paraíba and of Rio Grande do Norte, it was executed by the real troops. Like this, he tries to understand the Priest's conflicting relationship, while representative clergyman, of a Church that almost obtained a religious monopoly, and your ideals per centuries more gone back to a social and economical order of Illumines, that even certain point condemned the attitude of the own Church. The objective, then, is to understand through the path of priest's Miguelinho life, not only the intellectual, the teacher and the revolutionary, but the representation of your political and pedagogic-educational ideas in a die historical moment and the creation of the republican myth, looking for the plurality of an universe that seeks, per times, to flee of our theoretical context
Resumo:
The rational construction necessary to systematize scientific knowledge in physics, introduces difficulties of understanding in some of its concepts. One of these concepts which exemplify properly this difficulty in learning or teaching is entropy. This thesis propose the construction of a didactic route which constitute itself a historical and epistemological course to entropy, intending to contribute for teaching this concept as well as other physics concepts. The basic assumption to build this route is that through the historical review of the development of this concept in the way suggested by Bachelard s (1884-1962) epistemology it is possible to make subjects, to be taught and learned, more meaningful. Initially I composed a brief biographical note to give the reader an idea about the issues, interests and reflections, related to science, and how I dealt with them in my private and professional life, as well as the role they played to lead me to write this thesis. The strategy to construct the route to entropy was to split the usual contents of basic thermodynamics in three moments in a way they can constitute epistemological units , which can be identified by the way of thinking in the corresponding moments of scientific knowledge production: a technical and empiricist moment, a rationalist and positivist moment and a post-positivist rationalist one. The transition between each moment is characterized by a rupture with the former way of thinking; however the progress in the construction of knowledge in the area is evident. As the final part of this work I present an analysis based on elements of Bachelard s epistemology that are present in each moment. This analysis is the basic component of the didactic route that I propose myself to build. The way I made this route guide to entropy could contribute to the construction of other didactic routes in physics and other sciences, in a way to unveil hidden meanings and as a tool to humanize scientific knowledge.
Resumo:
This program resumes the history of the political-pedagogic actions on the Serviço de Assistência Rural SAR, of Natal archdiocese, and analyses the contributions of this actions on the process of rural workers organization in the social movements on the countryside. The educative actions of the RAS are happening in a permanent tension between the pedagogic project of a church in change and, a pedagogy of the groups, communities and social movements, that is centered in the cultural action, in the culture lived from its condition of citizens. This research reveals that this entity fulfilled a strategic attribution for the Natal s church on the formation of the community leaderships, at a first moment and leaderships for social movements. Before the military dictatorship, the work methodology of this entity had as priority, begin from the reality leaved by the rural workers in the expectation that these became to qualify themselves for a more citizen participation in the call development. During the military regime, the entity goes measuring theirs activities in the new context, until the moment that redefines the work line. Goes then defining regions and thematic of operation supporting the fights for land, salary campaigns, women agricultural workers organizations. The pedagogy of work has as one of its supporters the Paulo Freire s pedagogy, privileging the dialog as a source of production of knowledge from the reality leaved in a permanent transformation. The actions of this entity, with the groups and social movements, produces the necessary knowledge for the organization of the rural workers while individual and social subjects of a changing world. The process of action-reflection of the activities intended, by a creative form, a permanent production of strategies of fight of the workers. Research ever, not to make accommodate itself to the new knowledge acquired in the action-reflection it is part of the pedagogical idea of this Institution. One searched in this process of formation of the man and the woman to question the reality, to create actionreflection-action spaces on the fights for a possible transition of an ingenuous conscience for a critical conscience, in view of the transformation of the structures that oppresses them
Resumo:
The research aimed to analyze the feasibility of forming a network of municipal services to prevent and treat child victims of violence from the Basic Health Units in the Family Mossoró / RN. The research is a qualitative approach and was developed in the form of action research. The population was composed of representatives of institutions of the child and primary care professionals. Data were collected through questionnaires, workshops and semi-structured interview. The results were analyzed from data collected through the questionnaire designed to assess the material, lectures, dialogues and assessments with the team and presented in accordance with the findings of the research. The study was approved by the Ethics in Research UFRN with protocol No. 158/2010, CAAE: 0176.0.051.000-10. Situational diagnosis in the participants answered a questionnaire to characterize and then launched the guiding question of the focus group FHS While professional what your perception towards violence against children? It was felt the fear and ignorance on the part of the unit staff on how to prevent and to refer cases of violence against children and adolescents in the area of coverage of the unit and also realized that the professionals felt victims of occupational violence before the violence has reached proportions that the area of the unit. Mind the need to change strategies to work to combat violence, we plan to conduct focus group workshop to complete the questionnaire, training for protection against occupational violence, and meeting with other bodies responsible visor protecting children and adolescents to draw the flowchart of the victims in safety net. The next moment training to fill the notification form professionals were interested in learning and use this tool to combat violence. At the third meeting in Unity, meeting with representatives of the Child Protection Council, the professional unit showed interest in interacting with the agency to expose and combat violence against children and adolescents. Due to difficulties in the physical structure of the unit was not possible to continue the research and planned every moment, and then completed the data collection with interviews with the participating professionals, to assess the meetings. Therefore, it is considered that action research has also achieved its goals because the team was involved in the collective construction of a proposed change in the practices of referral and prevention of violence against children and adolescents. This involvement was favored using the principles Freirian during the course of the study. However, it is assumed that the network was not fully implemented because it is known that it is in a continual process of improvement and must continue evolving with the unit team.
Resumo:
The question of participation has been debated in Brazil since the 1980 decade in search a better way to take care of poulation s demand. More specificaly after the democratic open (1985) begins to be thought ways to make population participates of decisions related to alocation of public resources. The characteristic of participates actualy doesn t exist, population to be carried through is, at top, consulted, and the fact population participates stays restrict to some technics interests at the projects, mainly of public politics of local development. Observe that this implementation happens through a process and that has its limits (pass) that could be surpassed through strategies made to that. This dissertation shows results of a research about participative practices in city of Serrinha between 1997 and 2004, showing through a study of the case of Serrinha what was the process used to carry through these pratices in a moment and local considered model of this application. The analyses were developed through a model of research elaborated by the author based on large literature respects the ideal process to implant a participative public politics. The present research had a qualitative boarding, being explorative and descritive nature. The researcher (author of this dissertation) carried through all the research phases, including the transcriptions of interviews that were recorded with a digital voice recorder. Before the analysis of these data was verified that despite the public manager (former-mayor) had had a real interest in implant a process of local development in city, he was not able to forsee the correct process to do it. Two high faults were made. The first was the intention to have as tool a development plan, what locked up to make this plan was the booster of supossed participative pratice and no the ideal model that would be a plan generate by popular initiative. The second one was absence of a critical education project for the population that should be the fisrt step to carry through a politc like that
Resumo:
With the increasing offer of education services in Brazil, it is necessary to evaluate the quality of service in education, especially in those institutions for vocational education which have a greater interaction with the labor market, in order to form qualified professionals and meet the growing demand that the country has today[A1] . In Brazil, the evaluation of the quality of library services has influenced the assessment of educational institutions and in this context, there needs to be a process to monitor the quality of services provided by libraries. However, the service is not done in a single moment and thus to a more detailed assessment it needs to be measured and evaluated each different time the customer uses it. Therefore, the aim of this work consists in measuring the quality in every moment of truth of a cycle of library services to assess which are the most relevant moments in the client's perspective at the library of the Federal Institute of Education, Science and Technology of Rio Grande do Norte (IFRN) Campus João Câmara in building the overall quality of service. In the literature review, internal secondary sources were used, from the database of the institution studied, and also external sources, through literature in books, articles, dissertations, theses and journals on compost quality, service quality, cycle services, measuring quality, satisfaction, teaching activities, and on library services specifically. We applied a questionnaire to students in the library based on models of quality measurement SERVPERF and SERVQUAL and its variations such as SERVQUAL pondered and SERVPERF pondered . Through analysis based on concepts of reliability and validity of measuring instruments, it was found that the SERVPERF model is the instrument that most closely matches the dimensions of quality assessed in the library with customer satisfaction measured by the questionnaire. From there, the search results as measured by statistical techniques of analysis, indicated that the initial and final moments of truth of the cycle of service quality had the greatest influence on overall customer satisfaction with the library service