Estruturas tectônicas cenozóicas na porção leste da Bacia Potiguar - RN

This thesis encompasses the integration of geological, geophysical, and seismological data in the east part of the Potiguar basin, northeastern Brazil. The northeastern region is located in South American passive margin, which exhibits important areas that present neotectonic activity. The definition of the chronology of events, geometry of structures generated by these events, and definition of which structures have been reactivated is a necessary task in the region. The aims of this thesis are the following: (1) to identify the geometry and kinematics of neotectonic faults in the east part of the Potiguar basin; (2) to date the tectonic events related to these structures and related them to paleoseismicity in the region; (3) to present evolutional models that could explain evolution of Neogene structures; (4) and to investigate the origin of the reactivation process, mainly the type of related structure associated with faulting. The main type of data used comprised structural field data, well and resistivity data, remote sensing imagery, chronology of sediments, morphotectonic analysis, x-ray analysis, seismological and aeromagnetic data. Paleostress analysis indicates that at least two tectonic stress fields occurred in the study area: NSoriented compression and EW-oriented extension from the late Campanian to the early Miocene and EW-oriented compression and NS-oriented extension from the early Miocene to the Holocene. These stress fields reactivated NE-SW- and NW-SE-trending faults. Both set of faults exhibit right-lateral strike-slip kinematics, associated with a minor normal component. It was possible to determine the en echelon geometry of the Samambaia fault, which is ~63 km long, 13 km deep, presents NE-SW trend and strong dip to NW. Sedimentfilled faults in granite rocks yielded Optically Stimulated Luminescence (OSL) and Single-Aliquot Regeneration (SAR) ages at 8.000 - 9.000, 11.000 - 15.000, 16.000 - 24.000, 37.000 - 45.500, 53.609 - 67.959 e 83.000 - 84.000 yr BP. The analysis of the ductile fabric in the João Câmara area indicate that the regional foliation is NE-SW-oriented (032o - 042o), which coincides with the orientation of the epicenters and Si-rich veins. The collective evidence points to reactivation of preexisting structures. Paleoseismological data suggest paleoseismic activity much higher than the one indicated by the short historical and instrumental record

Indicadores do nível relativo do mar e evolução costeira durante o holoceno tardio no litoral oeste do Ceará, NE do Brasil

In the coastal region of Ceará, between the municipalities of Acaraú and Itapipoca, thirteen sites were identified containing indicators of relative sea level, six of these being dated by optically stimulated luminescence (OSL) and radiocarbon. Ages obtained supports that were formed prograding beaches in the study area. In the eastern portion, beaches in coastal plain deposits occur while a system lagoon/barrier paleomangrove occurs in the western portion of the study area. In both cases the coastal deposits prograde from east to west. Higher sea levels were identified between the current: (a) 3.110-2.830 cal. yr. BP; (b) 1.830 yr. BP (OSL) - 1.490 cal. yr. BP; (c) between 1.240-1.060 cal. yr. BP; (d) 845-715 yr. BP (OSL). Since then the sea level suffered by lowering the current level. Variations in sea level are interpreted as responses to changes in the pattern of marine circulation and do not exclude possible tectonic disturbances in the basin of the continental margin. The indicators of relative sea level west coast of Ceará present differently from other curves constructed in the coastal northeast, suggesting that local factors mentioned above contributed to sea level fluctuations.

Geomorfologia e neotectônica no Vale do Apodi-Mossoró RN

Numerous studies have indicated that the Potiguar Basin is affected by Cenozoic tectonics. The reactivation of Cretaceous fault systems affect the post-rift units, witch include Neogene and overlying Quaternary sediments. In this context, the objectives of this thesis are the followings: (1) to characterize the effects of post-rift tectonics in the morphology of Apodi Mossoró-river valley located in the central portion of the Potiguar, (2) to characterize the drainage of the Apodi Mossoró river valley and investigate the behavior of their channels across active faults, and (3) to propose a geologic-geomorphological evolutionary model for the study area. This study used a geological and geomorphological mapping of the central part of the basin, with emphasis on the Quaternary record, luminescence dating of sediments, and geoelectric profiles of the area. The results reveal by maps of structural lineaments and drainage channels of the rivers form valleys that are affected by faults and folds. In Apodi-Mossoró valley, anomalies of channel morphology are associated with the deformation of the post-rift basin. These anomalies show the reactivation of major fault systems in the Potiguar Basin in Cenozoic. On a regional scale, can be seen through the vertical electric profiles that the Cenozoic tectonics is responsible for the elevation of a macro dome NE-SE-trending 70-km long and 50km wide and up to 270 above sea level. In this sector, the vertical electric profiles data show that the contact between the Cretaceous and Neogene rise more than 100m. This Is an important feature of inversion data obtained in this work showed that the deposits that cover the macro dome (Serra do Mel) have ages of 119 ka to 43 ka. In the river valley and surrounding areas Apodi-Mossoró ages vary between 319 ka and 2.7 ka. From these data it was possible to establish the correct geochronological posiconamento paleodepósitos of distinguishing them from the fluvial deposits of the Neogene (Barreiras Formation)

Estudo do comportamento térmico e da luminescência de filmes de quitosana com os íons Eu3+ e Tb3+

Films of chitosan with trivalent lanthanides ions Eu3+ and Tb3+ were respectively prepared in the ratio of 3:1 m/m (chitosan: lanthanide) and 6:1 m/m (chitosan: lanthanide). There were no formations of films in a ratio of 1:1 m/m (chitosan: lanthanides). The films of chitosan with the Tb3+ ion have the same transparent appearance than the pure chitosan films. The film of chitosan with Eu3+ ion has a muddy appearance. These films present good resistance to tear. The appearance of the compounds prepared in ratio 1:1m/m is a white powder. The films and compounds of chitosan were characterized by Elementary Analysis (CHN), Thermal Analysis (TG/DTG) and Spectroscopy of Luminescence. The CHN analysis was made only for compounds prepared in ratio 1:1m/m, suggesting that these compounds possess the formula QUILn.6H2O, where QUI = Chitosan and Ln = Lanthanide. The results of the curves TG/DTG indicated that there are strong interactions between Eu3+ or Tb3+ and chitosan, causing a lesser lost of mass in the films. The luminescence analysis showed that the films of chitosan with the ions Eu3+ and Tb3+ present emissions in the region of the visible one, with bands of the chitosan and of the Eu3+ ion. The luminescence analysis of the compounds of chitosan with the Eu3+ and Tb3+ ions suggest that the chitosan does not transfer into energy to the ions lanthanides, however the chemical neighborhood around of the ion lanthanides breaks the selection rules and, conseqüently the 4f-4f transitions of the lanthanide ions are observed

Análise do transcriptoma das glândulas venenosas do escorpião Tityus stigmurus

In Brazil, accidents with scorpions are considered of medical importance, not only by the high incidence, but also for the potentiality of the venom from some species in determining severe clinical conditions. Tityus stigmurus is a widely distributed scorpion species in Northeastern Brazil and known to cause severe human envenomations, inducing pain, hyposthesia, edema, erythema, paresthesia, headaches and vomiting. The present study uses a transcriptomic approach to characterize the molecular repertoire from the non-stimulated venom gland of Tityus stigmurus scorpion. A cDNA library was constructed and 540 clones were sequenced and grouped into 37 clusters, with more than one EST (expressed sequence tag) and 116 singlets. Forty-one percent of ESTs belong to recognized toxin-coding sequences, with antimicrobial toxins (AMP-like) the most abundant transcripts, followed by alfa KTx- like, beta KTx-like, beta NaTx-like and alfa NaTx-like. Our analysis indicated that 34% include other possible venom molecules , whose transcripts correspond to anionic peptides, hypothetical secreted peptides, metalloproteinases, cystein-rich peptides and lectins. Fifteen percent of ESTs are similar to cellular transcripts. Sequences without good matches corresponded to 11%. This investigation provides the first global view of cDNAs from Tityus stigmurus. This approach enables characterization of a large number of venom gland component molecules, which belong either to known or atypical types of venom peptides and proteins from the Buthidae family

Contribuição da catodoluminescência para o entendimento da diagênese da formação Jandaíra: áreas do campo de petróleo da fazenda Belém e Lajedo do Rosário

The general objective of this study was to contribute to the understanding of the chemical evolution of fluids that percolate through carbonate rocks of the Jandaíra Formation. The oxidation and reduction conditions in which grains, source and cement were formed was investigated using the cathodoluminescence technique (CL). The study area is located in the west part of the Potiguar Basin (Fazenda Belém field) and Rosário Ledge (Felipe Guerra municipality, State of Rio Grande do Norte, Brazil). The analysis of thin sections of carbonate rocks under CL revealed that grains (allochemical or not) and diagenetic products (micritization, dolomitization, neomorphism and cementation) exhibit since absence of luminescence the various luminescence colors (yellow, orange, red, brown, and blue) in a variety of intensities. As pure calcite shows dark blue luminescence, the occurrence of different luminescence colors in calcite crystals suggest one or more punctual crystal defects such as free electron, free space and impurity. The dyeing of thin sections with alizarin and potassium ferrocyanide revealed the absence of ferrous carbonate in the different lithotypes of Jandaíra Formation. Therefore, the different colors and intensities of CL observed in these rocks are probably caused by the presence of ion activators such as Mn2+ and is not an activator/inhibitor combination. In the same way, the absence of luminescence is very probably caused by the absence of activator ions and not due to the low concentration of inhibitor ions such as Fe2+. The incorporation of Mn2+ in the different members of the Jandaíra Formation must have been controlled by the redox state of the depositional environment and diagenesis. Therefore, it is possible that the luminescent members have been formed (e.g.,ooids) or have been modified (gastropod neomorphism) under reduction conditions in the depositional environments, in subsurface during the burial, or, in the case of Rosario Ledge samples , during the post-burial return to surface conditions. As regards the sudden changes from low to moderate and to strong luminescence, these features should indicate the precipitation of a fluid with chemical fluctuations, which formed the frequent zonations in the block cement of the Rosario Ledge samples. This study suggests that the different intensities and colors of CL should be correlated with the Mn2+ and Fe2+ contents, and stable isotopes of samples to determine the salinity, temperature, pH e Eh conditions during deposition

Avaliação clínica e microbiológica das condições de saúde oral dos receptores de transplante renal do Hospital Universitário Onofre Lopes, Natal RN

Introduction: The chronic immunosuppression promotes the development of changes in the oral cavity of the kidney transplant recipients (KTR), however with the exception of gingival overgrowth, little is known regarding the prevalence of oral lesions in this population. Objective: To evaluate the prevalence of clinical and microbiological conditions of the oral cavity of the recipients of kidney transplantation and the associated factors. Methods: This was a cross-sectional study which examined 96 clinical KTR and experimental where collected saliva stimulated them to identify Candida sp. Data collection consisted of evaluation stomatologic, socio-demographic, clinical aspects of transplantation, condition of oral hygiene and dental caries, yonder to questions about knowledge of oral alteration after transplantation. Results: Of the total, 66.7% of KTR had some type of oral manifestation. The most common was saburral tongue, followed by gingival overgrowth, with both oral manifestations related to gender and concomitant use of cyclosporine and nifedipine (p <0.05). Tacrolimus showed a protective effect for gingival overgrowth (OR = 0.13). The oral hygiene was associated with saburral tongue(p = 0.03) and severity of gingival overgrowth (p = 0.0001). Oral candidiasis was diagnosed in 17.7% of patients and Candida albicans was isolated most frequently in the saliva of RTR with a colonization of 58.3%. The average DMF-T increased with age. The method of oral hygiene was most used brush and toothpaste to 61.5%. Changes in the oral cavity was seen in 54.2% of KTR, citing as the main growth and gingival ulcers. Instructions for oral hygiene after transplantation were neglected for 61.5% of RTR. Dry mouth and halitosis were reported in 30.2% and 36.5% respectively. Conclusions: More the half of the KTR had at least one injury of the mouth, the immunosuppressive drugs and oral hygiene are associated with these alterations. Prospective cohort studies are needed to elucidate the relationship between oral manifestations and levels of drug and risk of oral manifestations occur over time. The kidney transplant recipients showed to be aware of oral alterations occurred after transplantation and uninformed about the oral hygiene instructions. With regard to hygiene, the incidence of caries was considered high, conditions of risk were identified and improvements in primary attention should be encouraged and reflected in the monitoring of renal transplant

As crenças docentes sobre a criatividade a as práticas pedagógicas criativa: o caso do programa do ensino médio inovador no RN

Estamos vivendo no século da criatividade em que os sujeitos precisam ser estimulados a criar e inovar nos processos de aprendizagem escolar. Nesse sentido, a criatividade precisa ser compreendida como um bem cultural, um direito de todos e uma condição histórica e cultural do sujeito, e não como uma capacidade inerente ao sujeito ou pertencente alguns poucos eleitos. Para que a criatividade do aluno seja estimulada, faz-se necessário, dentre outros elementos, que o conhecimento profissional do professor considere as crenças como componente de seu processo de profissionalização com o objetivo de reconhecer o seu papel e influências como formas de nortear as ações profissionais docentes. Para tanto, a presente tese tem o objetivo de estudar as crenças dos professores sobre a criatividade dos estudantes no Ensino Médio Inovador. O ensino, nessa perspectiva, mais especificamente, o ensino médio precisa inovar-se, e nesse processo, o Programa Ensino Médio Inovador PROEMI emerge como uma das iniciativas das políticas públicas educacionais vigentes. Para tanto, no intuito de fundamentar as nossas discussões dialogamos com autores que discutem a criatividade no contexto da educação, às crenças, o conhecimento profissional do professor e o ensino médio. Nessa pesquisa, 207 professores que atuam no ensino médio em escolas estaduais na cidade de Natal e sua Região Metropolitana dentro do PROEMI constituíram-se em nosso público-alvo. O instrumento de coleta de dados foi um questionário normativo de crenças contendo perguntas fechadas e abertas. Para a organização dos dados utilizamos os softwares estatísticos R. 2.15.1 e o Modalisa. O tratamento dos dados se deu mediante análises estatísticas como a análise descritiva dos enunciados, da média, do desvio padrão e a Análise de Componentes Principais ACP em relação aos resultados oriundos das perguntas fechadas e a análise de conteúdo em se tratando dos resultados referentes às perguntas abertas. Os resultados corroboraram com a tese de que os professores apresentam em suas crenças a predominância do enfoque tradicional ou clássico da criatividade, ou seja, creem-na como algo inato ao ser humano e que se desenvolve independentemente dos fatores sociais e culturais. No tocante às principais características do aluno criativo, a autonomia e o alto grau de originalidade em sua aprendizagem se destacaram, dentre outras características. Suas crenças, em relação aos elementos que inibem a criatividade do aluno apontaram que a escola, ao privilegiar os conteúdos escolares compromete a criatividade dos alunos e sobre os elementos que favorecem, destacaram-se as áreas da Arte, da Educação Física e da Literatura como disciplinas, que preferencialmente, desenvolvem a criatividade dos alunos no contexto escolar. Assim, constatamos que as crenças dos professores se configuram de forma reducionista e inatista e que precisam, urgentemente, ser repensadas para que não continue a comprometer o desenvolvimento da criatividade do aluno no contexto escolar, e nesse caso, as crenças se constituem em um dos elementos básicos da profissionalização docente que precisam constantemente ser repensadas e incluídas nas discussões sobre a formação e atuação docente, principalmente, dentro do PROEMI que tem como objetivo principal inovar e estimular a criatividade dos alunos no ensino médio

Vozes não silenciadas de alfabetizandos jovens e adultos e suas repercussões na formação docente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

A aprendizagem na convivência:o estágio curricular em enfermagem

This is an analytic research of a qualitative nature whose purpose is to examine the learning process involving students of the Nursing Program of the Universidade Federal do Rio Grande do Norte UFRN who are attending the Supervised Clerkship in Nursing (SCN) in Family Health Strategy (FHS), based on learning through daily living. In order to do this, a historical overview of this academic activity in the teaching of nursing was presented, and the importance of FHS as the scene where professional health education takes place was discussed. For the empirical investigation, ten eighth-semester students involved in clerkship activities at family health units in the Western Sanitary District of Natal, Rio Grande do Norte, were interviewed. The theoretical approach relied, as epistemological presupposition, on the ideas of educator Humberto Maturana who showed that learning, both in nature and among human beings, takes place within dialogic living relationships wherein acceptance of the other, affectivity (love) and dialoguing are essential stimuli to learning. Students discourses gradually became part of the analytic categories that had been established beforehand. There has been verified that the students went through meaningful learning encouraged by all who shared the living environment, that is: nurse/instructor, teacher/supervisor, family health staff, and the community. Several feelings were involved in the process, such as joy, satisfaction, self-reliance, affectivity and, in the opposite direction, sadness, indignation, a feeling of impotence, and fear. The learning of interpersonal relationship was describe as the most relevant of the academic experiences and, therefore, thus emphasizing the relevance of affectivity to the learning process as Maturana points out. It is suggested that the teaching of nursing keep on giving priority to family health units as the Basic Care educational scene, with attention to the importance of placing the students in welcoming environments, in such a way as to encourage learning

Atuação da escola frente à violência: estudo comparativo entre duas instituiçoes de ensino

It is a descriptive, exploratory study, quantitative comparative approach, whose general objective was to analyze the violence at school in a comparative way in the context of two schools in Natal / RN. The specifics were to identify the types of manifestations of violence in the contexts of public and private schools, to identify the position of the leadership, teachers and school staff during and after the occurrence of manifestations of violence in the school environment, to identify measures to prevent violence within of schools. The results show that 68 of the 121 participants (56.20%) were female and 53 (43.80%) were male, 38 (31.40%) were between 40 and 49, 85 (70.2%) lived in the south of Natal (RN), 46 (38.02%) specialization, 68 (56.20%) were Catholic, 63 (52.07%) married, 41 (33.88%) received between 03 and 05 and 68 minimum wages (56.20%) were teachers, 51 (42.15%) 02 employees (01,65%) and directors, 46 (38.02%) providers had between 05 and 14 years and 11 months experience in teaching 70 (57.85%) less than five years in the job, 68 (56.20%) worked between 20 hours and 40 hours per week, 81 (16.30%) worked in the 9th grade of elementary school II. As for the sizing of violence, 111 (91.74%) respondents witnessed episodes of this event who work in the institution, 100 (82.64%) witnessed verbal violence, 87 (71.90%) called for parents when some event happenedviolent that it caused injury to students, 66 (54.55%) believed that family violence is the main reason for young people practiced bullying, 44 (38.98%) reported daily episodes of bullying, 64 (52.89% ) the event happens in the courtyard. Of the 37 victims of violence at school, 22 (59.45%) suffered verbal abuse, 18 (48.65%) experienced violence once a week, 36 (97.30%) were attacked by students, 104 (85.95 %) are able to differentiate the bad acts of bullying behavior, 28 (23.14%) separated the involved coordination and communicated verbally, 23 (19.00%) stated that the coordination of schools talked with parents about the aggressive behavior of the student. Regarding the actions taken to minimize bullying, 69 (57.02%) participated in any professional education process, 47 (38.84%) was the educational process at another institution, 49 (71.01%) took courses lasting 12 to 24 hours, 59 (48.76%) stated that interaction with parents and family was the most stimulated by the school to try to minimize and prevent the event and 116 (95.87%) participated in meetings at the institutions surveyed , 58 (50.00%) responded that the meetings took place every two months and 121 (100.00%) reported having no refresher course on school violence in the schools surveyed. We conclude that violence in schools has been expressed in any social class and that professionals are poorly prepared to deal with the situation. So we hope that education professionals through the reading of our study may realize that school violence takes place in any institution affecting the lives of all who make up the educational universe. It is extremely important that these professionals always seek to empower through knowledge so that they can develop strategies to prevent and minimize the bullying to change the reality of the workplace

No caleidoscópio o estresse da equipe de enfermagem da UTI de um Hospital Universitário em Natal-RN

This study aimed to analyze stress on nursing staff of intensive care at the Teaching Hospital Onofre Lopes. The study sample consisted of thirty-eight (38) nursing professionals, including technicians and nurses working in the ICU of the hospital Data were collected between September to November 2011 in two stages.The first was the application of the Lipp Stress Symptoms Inventory (LSSI), which allowed us to measure the stress phase in which each team member was. After that, data were tabulated in Microsoft Excel spreadsheets and analyzed according to the 2010 inventory guidelines proposed by the author. After this analysis it was possible to complete the second phase of the research, which consisted of a semi-structured interview designed for those workers who were in the second phase of stress, resistance. Data analysis was based on Bardin 2004 content analysis, enabling the creation of categories based on grouping the ideas present in the interviewees' statements. It was found that the study population was mostly female (78.9%) aged from 30 to 39 years (50%), married (52.3%) and with dual-employment (65.7%). The most predominant phase, according to the Lipp inventory, was the stress resistance, present in 44.7% of the team and having as most predominant physical symptoms the constant feeling of physical exhaustion, verified in 16.8% of the participants, and psychological, the excessive irritability and emotional sensitivity in 26.3%. Regarding the qualitative data it was possible to establish three categories and four subcategories, with the following categories: the stressors of the workplace, overwork and the interpersonal relationships of the nursing staff in the ICU. And as subcategories: Routine care in the ICU; Pressures and Individual Charges; double journey: professional reflections on daily life, the night shift nursing staff and the body suffers, the manifestations of stress; deficient communication between team members. Thus, this study allowed the visualization of the stress phenomenon on nursing staff of the Teaching Hospital Onofre Lopes as a kaleidoscope of thoughts, feelings and experiences perceived by these professionals in different areas of their lives. It was also verified that the strengthening of the stress theme among nursing professionals need to be exploited and stimulated in several nursing areas of discussion so these workers are encouraged to take better care of themselves so they can take care of others health

O cuidado compartilhado entre mães e educadoras de um centro municipal de educação infantil: uma pesquisa-ação

O cuidado à criança envolve a identificação e o atendimento às necessidades de modo a oferecer-lhe atenção como pessoa em contínuo processo de crescimento e desenvolvimento. Contudo, o cuidado oferecido à criança que convive em instituição escolar está permeado por conflitos que fragilizam a relação família-escola, não sendo estimulada a articulação desses atores no que refere ao cuidar da criança. Diante dessa problemática, objetivou-se analisar a construção de um pacto do cuidar entre mães e educadoras de crianças que frequentam um Centro Municipal de Educação Infantil. Trata-se de um estudo qualitativo, tendo como método a pesquisa-ação. Envolveu doze mães e oito educadoras de uma instituição de educação infantil de Cidade Nova, no município de Natal, no período de abril a novembro de 2013. Os dados foram coletados através de entrevista grupo focal, observação participante, seminários e diário de campo. Os resultados foram analisados seguindo o direcionamento da análise temática freireana. Na etapa do diagnóstico situacional, que investigou a realidade vivenciada pelas participantes do estudo, percebeu-se que as educadoras não se sentem preparadas para lidar com aspectos de saúde-doença da criança e recusam as ações de cuidado como desempenho de suas funções, interpretada como uma atitude que ultrapassa sua competência profissional. Os pais, por sua vez, apresentaram dificuldade de entendimento e clareza da sua função e relação com a instituição e executam as ações de saúde sem associá-lo à promoção e prevenção, além de realizarem com conhecimento empírico. Vista a necessidade de mudança das ações de saúde prestadas à criança, decidiu-se conjuntamente, através de uma roda de conversa, realizar capacitações sobre higiene e limpeza, medidas caseiras no cuidado à criança e primeiros socorros. Na etapa de implementação da ação coletiva as participantes consideraram as atividades úteis no cuidado prestado à criança e perceberam a importância do cuidado compartilhado para o desenvolvimento infantil. Com o desenvolvimento das capacitações, as participantes sentiram a necessidade de sistematizar as atividades prestadas à criança nos problemas de saúde e, para tanto, foram construídos, conjuntamente, protocolos e procedimentos operacionais padrão para a formalizar as ações. Na etapa de avaliação dos encontros, constatou-se que há expectativas positivas para a continuidade do cuidado em comunhão entre pais e educadores, pois foram construídas novas percepções em relação ao cuidado da criança. Percebeu-se mudança considerável nas mães assíduas ao estudo quanto ao cuidado e interesse, no entanto tornaram-se evidentes as fragilidades no processo de trabalho do CMEI, pois emergiram a dificuldade existente nos membros que compõe a instituição de educação infantil de articular o cuidado à educação. Como principal dificuldade, elenca-se o alto índice de mães faltosas e a dificuldade de articular com outros profissionais de saúde para as atividades. Considera-se que o pacto de cuidar não foi implantado integralmente, pois partilhar cuidados sugere o encontro de pais e educadores que podem ter aspectos divergentes sobre necessidades infantis e desenvolvimento, o que requer constante negociação entre as partes. Nesse sentido, constitui-se em um processo contínuo de aperfeiçoamento entre família e instituição de educação infantil

Desenvolvimento de material compósito a base de raspa de pneu e látex para isolamento térmico

The process of recycling has been stimulated by the markets for several reasons, mainly on economical and environmental. Several products have been developed from recycled materials that already exist as well as several residues have been studied in different forms of applications. The greater majority of the applications for thermal insulation in the domestic, commercial and industrial systems have been elaborated in the temperature ranges between low to medium reaching up to 180oC. Many materials such as glass wool, rock wool, polystyrene are being used which are aggressive to the environment. Such materials in spite of the effectiveness in the retention of heat flow, they cost more and when discarded take several years to be absorbed by the nature. This way, in order to adapt to a world politics concerning the preservation of the environment, the present study was intended to develop a material composed of natural/biodegradable materials and industrial residues. The development of such a product in the form of a composite material based on tyre scrapes and latex for thermal insulation is presented in this research work. Thermal and physical properties of the tire scrapes as well as latex were studied in order to use them as raw materials for the manufacture of the intended composite to be applied as a thermal insulator in hot and cold systems varying between 0ºC and 200oC, respectively. Composite blankets were manufactured manually, in weight proportions of 1:1 (50:50%); 1:2 (33:67%) and 2:1 (67:33%) (tire scrapes: latex) respectively. Physical, mechanical and thermal properties of the composites were analyzed to obtain data about the viability of using the composite as a thermal insulator. The analyses carried out were based on standards ABNT, ASTM and UL. The maximum temperature obtained for the composite as a thermal insulator was 200ºC, which meets the range of applications that could be used as a thermal insulator in domestic as well as industrial purposes. The experimental results prove that the composite can be used as a thermal insulator on heated or cooled surface

Sistemas Nanoestruturados: Heteroestruturas Quasi-Periódicas de Nitretos e Cálculos Ab initio em Polimorfos CaCO3

The physical properties and the excitations spectrum in oxides and semiconductors materials are presented in this work, whose the first part presents a study on the confinement of optical phonons in artificial systems based on III-V nitrides, grown in periodic and quasiperiodic forms. The second part of this work describes the Ab initio calculations which were carried out to obtain the optoeletronic properties of Calcium Oxide (CaO) and Calcium Carbonate (CaCO3) crystals. For periodic and quasi-periodic superlattices, we present some dynamical properties related to confined optical phonons (bulk and surface), obtained through simple theories, such as the dielectric continuous model, and using techniques such as the transfer-matrix method. The localization character of confined optical phonon modes, the magnitude of the bands in the spectrum and the power laws of these structures are presented as functions of the generation number of sequence. The ab initio calculations have been carried out using the CASTEP software (Cambridge Total Sequential Energy Package), and they were based on ultrasoft-like pseudopotentials and Density Functional Theory (DFT). Two di®erent geometry optimizations have been e®ectuated for CaO crystals and CaCO3 polymorphs, according to LDA (local density approximation) and GGA (generalized gradient approximation) approaches, determining several properties, e. g. lattice parameters, bond length, electrons density, energy band structures, electrons density of states, e®ective masses and optical properties, such as dielectric constant, absorption, re°ectivity, conductivity and refractive index. Those results were employed to investigate the confinement of excitons in spherical Si@CaCO3 and CaCO3@SiO2 quantum dots and in calcium carbonate nanoparticles, and were also employed in investigations of the photoluminescence spectra of CaCO3 crystal