As relações da tríplice hélice no setor da carcinicultura do Rio Grande do Norte: uma análise a partir das abordagens da imersão social e da dependência de recursos

This work consists in a study of the Shrimp Industry in the state of Rio Grande do Norte, whose central issue relates to the understanding of how the Triple Helix (University, Government and the productive sector) interrelationship limits or expands the industry s innovation process. The study aims to understand how the Triple Helix relationship interferes in the innovation process of shrimp in Rio Grande do Norte. As the knowledge becomes the resource key for production methods, the generation of new technologies, new products and processes which demands joint and integrated action of the institutions comprising the Triple Helix: University, Government and productive sector, which possess the essential resources to innovate the process and can be maximized from cooperative relationships between the referred Institutions. Thus, in this work, it was sharply used the pioneering studies of Sabato and Botana (1968) regarding the cooperation relationship between the scientific-technological sphere, the governmental and the productive base, and studies on the Triple Helix approach, proposed by Etzkowitz and Leydesdorff (2000), in which the university has a key role in the process of technological and innovative development of countries and regions, and under which it is assigned to the very University - the character of the entrepreneurial institution, through the concept of entrepreneurial University. Aiming to overcome the criticism of Cooke (2005), regarding the limitations of the Triple Helix approach, in this study it was used - as analytical perspectives - the perspective of social immersion (Granovetter, 1985, 2005) and the theory of resources dependence (PFEFFER; SALANCIK, 1978). The analytical perspectives presented in here, despite of the different assumptions, are essential to eliminate the bias that one only approach can lead (ASTLEY; VAN DE VEM; 2007). The authors arguments focus on the fact that the integration is possible if the researcher acknowledged that different perspectives may have different descriptions of the same phenomenon. As a research strategy, this study is characterized as a study case, along with the proposed objectives - the qualitative method was used as an approach and, depending on the gathering of the sector s historical, a sectional longitudinal view approach was applied (VIEIRA, 2004). The primary and secondary data were used in order to understand the sector s evolutionary process and its inter-institutional relations - regarding the shrimp culture in Rio Grande do Norte - to promote the development, as the content was used for the technical analysis (BARDIN, 1977). The approach of social immersion and resources addiction dependence made it possible to understand that relationships are established within and between each sphere (university, government and productive sector) characterizing a network of low density relationships and strongly internal and external dependence. Based on the speech of Etzkowitz and Mello (2006), a successful Triple Helix strategy of innovation requires not only the involvement and commitment of the parts, within the institutional sphere and among them, but also the development of mechanisms to coordinate the multiple and complex interactions and interfaces, focusing on promoting both environment and context for innovation and learning; it can be acknowledge from study results that the shrimp in the State of the RN, although there are several institutional mechanisms to promote greater integration and technological development, has been presented disjointed - both internally and between the spheres - and under no legitimate practice when facing the innovational promotion and integration institutions. Due to those factors, the central institutions of the network are crucial to the promotion of innovations, spreading through their direct contacts the importance factor of the sustainable competitive activity in the world market and on the national level. However, it may be concluded, from the data, that the Triple Helix relations are interfering in a negative way on what concerns the promotion of innovations in the shrimp industry in RN

Da bancada ao Bureau: análise do desenvolvimento da biotecnologia no Nordeste Brasileiro sob o enfoque de Sistema Regional de Inovação

The starting point of the present work consisted of investigating the development of biotechnology in the Northeast region of Brazil from the perspective of a Regional Innovation System (RIS). The theoretical framework adopted relied on the approaches and concepts presented by the Neo-Schumpeterian perspective. This framework was chosen because, by means of the Innovation System concept, this literature allows us to analyze the relationships and configurations of actors, as well as the role of the state and of social, science and technology, and economic policies in the studied region. The analysis considered four selected dimensions: physical infrastructure, human capital, scientific production, and funding. These variables were chosen because they allow us to verify the possibilities and limitations of developing a biotechnology RIS in the Northeast of Brazil, and these elements would help in answering the question behind this dissertation. The location of the physical infrastructure was determined by means of bibliographic and documental research and interviews with heads of institutions that do biotechnology research. Regarding human capital, the analysis focused on resource training in biotechnology, highlighting graduate courses and research groups in the area. To measure knowledge production, we delimited scientific collaboration among researchers in the field of biotechnology as the focus of this category. For the funding dimension, information was gathered from reports available at the websites of national and state funding agencies. The data was analyzed through method triangulation, involving quantitative and qualitative research stages. To back the analyses, we revisited the integration policies in the area of Science, Technology and Innovation. Our analysis has shown that these policies play a crucial role in the development of biotechnology in the region being studied. The data revealed that the physical infrastructure is concentrated in only three states (Bahia, Ceará, and Pernambuco). In this regard, the Northeast Biotechnology Network (Renorbio) stands out as a strategic actor, enabling states with poor infrastructure to develop research through partnerships with institutions located in another state. We have also verified that the practices involving human resource training and knowledge production are factors that enable the emergence of a regional system for biotechnology in the studied region. As limitations, we have verified the low immersion level of regional actors, the heterogeneity of socioeconomic indicators, the lack of financial resources, and a low innovation culture in the business sector. Overall, we have concluded that the development of a Regional Innovation System in Biotechnology, based on the current regional dynamics, depends on an effective change in the behavior of the social agents involved, both in the national and regional dimensions as well as in the public and private spheres

Estudos de Durabilidade Frente ao Ataque Ácido de Compósitos Portland-Polímero para Cimentação de Poços de Petróleo

Portland-polymers composites are promising candidates to be used as cementing material in Northeastern oil wells of Brazil containing heavy oils submitted to steam injection. In this way, it is necessary to evaluate its degradation in the commonly acidizind agents. In addition, to identify how aggressive are the different hostile environments it is an important contribution on the decision of the acidic systems to be used in. It was investigated the performance of the Portland-polymer composites using powdered polyurethane, aqueous polyurethane, rubber tire residues and a biopolymer, those were reinforced with polished carbon steel SAE 1045 to make the electrochemical measurements. HCl 15,0 %, HCl 6,0 % + HF 1,5 % (soft mud acid), HCl 12,0 % + HF 3,0 % (regular mud acid) and HAc 10 % + HF 1,5 % were used as degrading environment and electrolytes. The more aggressive acid solution to the plain Portland hardened cement paste was the regular mud acid, that showed loss of weight around 23.0 %, followed by the soft mud acid, the showed 11.0 %, 15.0 % HCl with 7,0 % and, at last the 10.0 % HAc plus HF 1.5 % with just 1.0 %. The powdered polyurethane-composite and the aqueous polyurethane one showed larger durability, with reduction around 87.0 % on the loss of weight in regular mud acid. The acid attack is superficial and it occurs as an action layer, where the degraded layer is responsible for the decrease on the kinetic of the degrading process. This behavior can be seen mainly on the Portland- aqueous polyurethane composite, because the degraded layer is impregnated with chemically modified polymer. The fact of the acid attack does not have influence on the compressive strength or fratography of the samples, in a general way, confirms that theory. The mechanism of the efficiency of the Portland-polymers composites subjected to acid attack is due to decreased porosity and permeability related with the plain Portland paste, minor quantity of Ca+2, element preferentially leached to the acidic solution, wave effect and to substitute part of the degrading bulk for the polymeric one. The electrolyte HAc 10 % + HF 1,5 % was the least aggressive one to the external corrosion of the casing, showing open circuit potentials around +250 mV compared to -130 mV to the simulated pore solution to the first 24 hours immersion. This behavior has been performed for two months at least. Similar corrosion rates were showed between both of the electrolytes, around 0.01 μA.cm-2. Total impedance values, insipient arcs and big polarization resistance capacitive arcs on the Nyquist plots, indicating passivity process, confirm its efficiency. In this way, Portlandpolymers composites are possible solutions to be succeed applied to oilwell cementing concomitant submitted to steam injection and acidizing operation and the HAc 10,0 % + HF 1,5 % is the less aggressive solution to the external corrosion of the casing

Estudo da incorporação de cascalho proveniente da perfuração de poços de petróleo em formulações para tijolos de solo-cimento

The present work is to study the characteristics and technological properties of soil-cement bricks made from binary and ternary mixtures of Portland cement, sand, water, with or without addition of gravel from the drilling of oil wells, which could be used by industry, aiming to improve its performance and reduce cost by using the residue and, consequently, increasing its useful life. The soil-cement bricks are one of the alternatives to masonry construction. These elements, after a short curing period, provide compressive strength similar to that of solid bricks and ceramic blocks, and the higher the resistance the higher the amount of cement used. We used the soil from the city of São José do Mipibu / RN, the banks of the River Baldun, cement CPIIZ-32 and residue of drill cuttings from oil wells drilling onshore wells in the town of Mossley, RN, provided Petrobras. To determine the optimum mix, we studied the inclusion of different residues (100%, 80%, 70%, 60% and 50%) where 15 bodies were made of the test piece. The assessment was made of bricks made from simple compression tests, mass loss by immersion and water absorption. The experimental results proved the efficiency and high utilization of the waste from the drilling of oil wells, making the brick-cement-soil residue with a higher strength and lower water absorption. The best result in terms of mechanical strength and water absorption for the ternary mixture was 10% soil, 14% cement and 80% residue. In terms of binary mixtures, we obtained the best result for the mix-cement residue, which was 14% cement incorporated in the residue

Estudo de inibidores de corrosão em concreto armado, visando a melhoria na sua durabilidade

This thesis has as objective presents a methodology to evaluate the behavior of the corrosion inhibitors sodium nitrite, sodium dichromate and sodium molybdate, as well as your mixture, the corrosion process for the built-in steel in the reinforced concrete, through different techniques electrochemical, as well as the mechanical properties of that concrete non conventional. The addition of the inhibitors was studied in the concrete in the proportions from 0.5 to 3.5 % regarding the cement mass, isolated or in the mixture, with concrete mixture proportions of 1.0:1.5:2.5 (cement, fine aggregate and coarse aggregate), superplasticizers 2.0 % and 0.40 water/cement ratio. In the modified concrete resistance rehearsals they were accomplished to the compression, consistence and the absorption of water, while to analyze the built-in steel in the concrete the rehearsals of polarization curves they were made. They were also execute, rehearsals of corrosion potential and polarization resistance with intention of diagnose the beginning of the corrosion of the armors inserted in body-of-proof submitted to an accelerated exhibition in immersion cycle and drying to the air. It was concluded, that among the studied inhibitors sodium nitrite , in the proportion of 2.0 % in relation to the mass of the cement, presented the best capacity of protection of the steel through all the studied techniques and that the methodology and the monitoring techniques used in this work, they were shown appropriate to evaluate the behavior and the efficiency of the inhibitors

O erotismo mítico da ninfeta

This dissertation establishes a viewpoint in the Social Cience Field of the Nymphs image in the romanesque construction of the twentieth century based in modern archaeology. Our literary corpus is constitututed by the book of the russian author callled Wladimir Nabokov entlited Lolita and the book Presença de Anita, from a brazilian author called Mario Donato. Both works had a singular repercussion involving an erotic conception wich was faced as pornographic and baffling. We appeal to Georges Bataille‟s and Foucault‟s discussion in order to observe it through an erotic viewpoint from an inner experience not submitted to normalizations. Such experiences provoke a feeling of something unknown and it reflects wild singularities proposed by Foucault and related with many misunderstanding things presented in institutions and cultures. Furthemore Bataille‟s conception about erotism will give us conditions to analyze nymphs‟ bodies in order to see themselves from their main characteristics, such as seduction and tempting and maligning forces. We still aim to focus the paradigm of mankind and nature in the direction presented by Edgar Morin. He analyzes some feelings that nymphs provoke and their relation between men and death. In adittion, we present in this issue some questions between culture and biology, focusing on the initial period of larva (wich means the beggining), bringing up what is ready to be born, a mythical and significant body shown in the media. Lolita in the cinema and A Presença de Anita in the TV was disturbing in society and it projected the possibility of a syntaxes of desire. It can has a symbolic purpose or it can be a kind of social and cultural phenomenon, wich is an object of representation. Our purpose is to immersion/emerge in the Nimphs‟s body with adventure and its risks at the same time in wich we are crossing frontiers

Visões da cidade : da cidade histórica aos bairros da Cidade Alta e Ribeira em Natal-RN

The present work is an initiative of undertaking a perspective that values the aspects of the city in its diversity. The one that t intends is to discuss the urbanity starting from the aspect of the image, of the history, and about main point, to value the point of the individual's view that lives the urban space in its more several configurations: the house, the street, the neighborhood, and the city in wider scale. The described historical research defines the city as space of the human accomplishments. When analyzing the moments of the most recent history of the urban life the modernity/post-modernity notions they are explored in the sense of illuminating the wealth, continuity and it breaks of patterns of behavior, and on the other hand, to describe a I overfly in the several times of the city. The prominences of aspects of the archaeology and of the descriptive resource they are related, for its time, the most punctual perspective of the practical research, the instance of the neighborhood, specifically High City and Riverside, configuring an immersion in the daily more punctual of the city, valuing forms of being, aiming the perspective of the personal computer as point-of-view. The images of the city assume the paper of representing the documental about the current features of the urbanity. It is without a doubt that at the present time the photographic image already possesses a paper of prominence it is as research instrument, be as main source for a work on files of photos. The photographic images in the present work possess a prominence place, focusing specific places of the city in the time. Finally, the individual's voice valued under the perspective on as the person's knowledge that inhabits and live the urbanity he/she understands the knowledge of the life in the city and, more than in any other place, a middle where the loss of action models is pointed very easily tends in view the dynamic movement of the practices and renewal of new indications; in the same space in that becomes urgent to build marks starting from which the individual can shimmer the future. And in that space the individual's voice is valued as rich source of information on living the scenery of conflicts of the present time

Podcast na educação brasileira: natureza, potencialidades e implicações de uma tecnologia da comunicação

This thesis aims to build a panoramic analysis with the intention of providing the theoretical initial a thought articulated educational of podcast, a technology orality distributed demand. This joint search considering the various spheres that educational technology in Brazilian use, both in school and non-school contexts, including scenarios and distance. This study unites questions addressed piecemeal in the area to new perspectives about the podcast, in order to characterize its nature, examining such technology from a perspective of educational technology itself, as well as unveiling its main potentials and implications. The survey was conducted from the combined use of quantitative and qualitative categories, with emphasis on the last one. The method of participant observation was followed by immersion of the researcher in the audience groups of Brazilians podcasts. Data collection with sources held in non-school contexts, from a look at targeted interactions given the blogs of Brazilian productions, as well as from open-ended interviews with producers - made online - besides giving themselves from the hearing itself about five hundred podcasts of Brazil. In the school context, the research focused on a literature review of the literature of the study area. Were added to the corpus described statistics derived mainly from "Podpesquisa 2009," Numerical major survey on the use of podcasts in Brazil. The articulation and analysis of the collected data, we used the concept of Education Paulo Freire (1971, 1987), so that, understanding it as synonymous to communication - understood this concept in Freire - were able to reveal the various ramifications educational podcast Brazilian atmosphere permeated by a dialogic between its participants. Moreover, the ideas of Célestin Freinet (1998) about the cooperation, while education practice, conducted the analyzes productive technology addressed in this work. The philosophical thought of Andrew Feenberg (2003) on the notion of "technologies" buoyed technological design elaborate. Such consideration provided the foundation for the reflections and proposals offered in this study, which, in the characterization of the oral nature of the podcast - especially their version for the deaf - appropriated the placements Luis Antonio Marcuschi (2001) about the relationship between orality and writing. In addition to these references, several other authors were considered, dealing with issues that pervade the theme here delimited, contemplating discussions on topics such as educational interest, online production, inclusive education, among other aspects. At the end, there was the podcast as a technology, while still reproducing social asymmetries Brazilian fairly directed at promoting mitigations hierarchical and open production in digital orality promotes. In view of its technical and educational implications in national use, the technology study has revealed potential relevant to the sophistication of teaching practices with orality, in various contexts, and proved adequate to serve as a motto to the revision of school practices, to even the very role of the school. This, by the prospects unveiled here, can, through the podcast, mitigate their questions reproductivist to constitute themselves as under privileged communication, boosted by critical rescue and sophistication of management through the most basic education component: speech

Estudo do comportamento mecânico de areias artificialmente cimentadas

Soil improved with the addition of cement have been utilized as an alternative to the construction of various types of geotechnical works, almost always present economic and environmental advantages. This paper presents a study on the usage of cement in the improvement of mechanical properties of sandy soils, characteristic of the region of Natal, collected from its dunes. This research was made in order to analyze the influence of cement content, voids, and also including water immersion and confining pressure. Samples molded from cement-soil mixtures were tested for unconfined compression tests and triaxial tests. The samples had the percentage of cement mixed in 2.5%, 5% and 10% by weight. The cement agent used was the Portland Cement of High Early strength(CPV-ARI), which promoted agility to the experimental procedure for presenting a rapid gain in strenght. The void ratio used ranged from 0.7 (more compact), 0,9 and 1,1(softer). The soil under study can be considered as pure sand. In general, it can be stated that the larger the amount of cement added to the sand studied is, the greater ultimate strength will be. Likewise, as more compact the soil is, the less void ratio and more resistant it will be present. The confining pressure tends to increase the resistance of the specimens. The cementing adopted grades showed that the use of different criteria for failure did not significantly alter the stress-strain parameters for the sand studied. The angle of friction values were found within the typical range of medium and compact sands. Cementing acted in the sand providing an intercepted cohesion which increased enhancing the potential cementation. In triaxial compression tests, the sand with void ratio is equal to 0.7 and showed the expected behavior for a compact sand while the stress-strain behavior of the same sand with the void ratio of 0.9 tended to be expected for the soft sand as well

Desempenho de argamassas produzidas com agregados reciclados oriundos do resíduo de construção e demolição da Grande Natal-RN

The construction industry is responsible for generating a lot of waste because of their activities. Consequently, it is noticeable the occurrence of environmental problems in terms of its disposal in inappropriate places. Faced with this problem, some studies have been conducted with the aim of developing technologies and alternatives for recycling construction and demolition waste (CDW), motivated by the scarcity of natural resources and reduction of environmental problems generated. The research aims to characterize the recycled aggregates derived from construction and demolition waste (CDW) produced in the Greater Natal-RN and analyze the performance of mortar coating produced with recycled aggregates. The study includes the chemical , physical and microstructural characterization of recycled aggregates , as well as conducting microscopic analysis and laboratory tests in the fresh state (consistency index , water retention , bulk density and content of entrained air ) and in the hardened state ( compressive strength , tensile strength in bending , water absorption by immersion and capillary , mass density and void ratio ) for mortars produced from different levels of substitution of aggregates ( 0, 20 %, 40 %, 60 %, 80 % and 100 %). The results were satisfactory, providing mortars produced with recycled aggregates, smaller mass density and dynamic modulus values as well as an increase in the rates of absorption and porosity. The tensile strength in bending and compression for TP1 (1:2:8) trait were lower for mortars produced with recycled aggregates and the best result was 20% for replacement. For the TP2 (1:8) mapping, there was an increase in resistance to traction and compression and the best result was for 100% replacement of natural aggregates by recycled. The experiments led to the conclusion that the technical and economic point of view that the mortars produced with recycled aggregates can be used in construction, only if there is an effective control in production processes of recycled aggregate and at the dosage of mortars

Arquitetura para aplicações interativas imersivas de televisão digital

In this work, we propose a new approach to Interactive Digital Television (IDTV), aimed to explore the concepts of immersivity. Several architectures have been proposed to IDTV, but they did not explore coherently questions related to immersion. The goal of this thesis consists in defining formally what is immersion and interactivity for digital TV and how they may be used to improve user experience in this new televisive model. The approach raises questions such as the appropriate choice of equipment to assist in the sense of immersion, which forms of interaction between users can be exploited in the interaction-immersion context, if the environment where an immersive and interactive application is used can influence the user experience, and which new forms of interactivity between users, and interactivity among users and interactive applications can be explored with the use of immersion. As one of the goals of this proposal, we point out new solutions to these issues that require further studies. We intend to formalize the concepts that embrace interactivity in the brazilian system of digital TV. In an initial study, this definition is organized into categories or levels of interactivity. From this point are made analisis and specifications to achieve immersion using DTV. We pretend to make some case studies of immersive interactive applications for digital television in order to validate the proposed architecture. We also approach the use of remote devices anda proposal of middleware architecture that allows its use in conjunction with immersive interactive applications

Estudo da flamabilidade e resistência à chama de compósito de poliéster insaturado e fibra da folha do abacaxizeiro (PALF)

In the present research work, composites were prepared using pine apple leaf fibres (PALF) as reinforcement with unsaturated polyester resin as matrix, incorporating with fire retardant at different compositions. The PALF was obtained from the decortication of pine apple leaves obtained from Ramada 4 from Ielmo Marinho in the State of Rio Grande do Norte. The unsaturated polyester resin and the catalyzer were bought from the local establishment. The fire retardant, aluminium tri-hydroxide - Al(OH)3 was donated by Alcoa Alumínio S.A and was used in the proportions of 20%, 40% and 60% w/w. Initially the fibres were treated with 2% NaOH for 1 hour, to remove any impurities present on the fibre surface, such as wax, fat, pectin and pectate, in order to have a better adsorption of the fibres with the matrix as well as the flame retardant. The fibre mat was prepared in a mat preparator by immersion, developed in the Textile Engineering Laboratory, at the UFRN. The composites (300x300x3 mm) were prepared by compression molding and the samples (150x25x3 mm) for analysis of the properties were cut randomly using a laser cutter. Some of the cut samples were used to measure the smoke emission and fire resistance using UL94 standard. Mechanical tension-extension and flexural properties were carried in CTGás RN and the Laboratório de Metais e Ensaios Mecânicos Engenharia de Materiais UFRN , as well as SEM studies were carried out at Núcleo de Estudos em Petróleo e Gás Natural - UFRN . From the observed results, it was noted that, there was no marked influence of the fire retardant on the mechanical properties. Also in the water absorption test, the quantity of water absorbed was less in the sample with higher concentration of fire retardant. It was also observed that the increase in the proportion of the fire retardant increased the time of burning, may be due to the compactness of the composite due to the presence of fire retardant as a filling material even though it was meant to reduce the rate of inflammability of the composite

Compósito reforçado com sisal para aplicação na moda

The objective of this research is the fabrication of a composite reinforced with dyed sisal fiber and polyester matrix for application in the fields such as, fashion, clothing, interior textiles; fashion accessories are some of the examples. For the fabrication of the composite, the sisal fibers were subjected to processes such as: chemical treatment with sodium hydroxide (NaOH) in the removal of impurities; bleaching for removing the yellowish color of the natural fiber and dyeing with direct dyes to confer the colors blue, green and orange. The search for new technologies ecologically correct has become a major concern in recent decades. Studies show that composite polymer reinforced by natural fibers is suitable for a large number of applications, and its use is advantageous in terms of economic and ecological. The dyed fibers were cut to a length of 30 mm, is used in the confection of webs. For this purpose, a web preparer by immersion, developed in the Laboratory of Chemical Textile of UFRN. The composite sheets measuring 300 x 300 x3 mm were molded by compression, with unsaturated orthophthalic polyester as matrix, and the samples in sizes 150 x 25 x 3 mm were cut with the aid of a laser machine, to be subjected to traction and flexion. The mechanical properties of traction and flexion in three points were performed in the Laboratory of metal and mechanical tests of Materials Engineering of UFRN. The resulting samples from the tests were evaluated in scanning electron microscope (SEM) at CTGas RN. On the basis of the analysis of the results from the mechanical tests, it was observed that the composite had good mechanical behavior, both in traction as in flexion. Furthermore, it was observed that in the water absorption test, the samples had a different percentage among themselves, this occurred due to the variation of density found in the fibre webs. The images of the SEM showed the failures from the manufacturing process and the adhesion of fibre/matrix. When the samples were prepared with the dyed fibers to be applied in fashion, the results were positive, and it can be concluded that the main objective of this work was achieved

Estudo comparativo das propriedades mecânicas em compósitos da fibra modal e poliester

In the present work, three composites with distinct reinforcements (polyester, modal e polyester + modal), all if a unsaturated orthophthalic polyester resin as matrix were used, in order to conduct a comparative study by mechanical tests and water absorption. The fibre mats were prepared in a mat preparatory by immersion developed in the Textile Engineering Laboratory. The composites were manufactured using a closed mould process by compression using an unsaturated orthophthalic polyester resin as matrix and 1% MEK (methyl ethyl ketone peroxide) as an initiator. In each composite twelve samples with the dimensions of 150x25x3 mm were cut randomly for the mechanical analysis (tension x extension, three points bending and water absorption and Scanning Electron Micsroscopy). The mechanical tests were carried out in the Laboratório de Metais e Ensaios Mecânicos UFRN . All the analyses were carried out according to the ASTM norms. The resultant samples from the mechanical analysis were subjected for the Scanning Electron Microscopy analysis. Based on the results obtained, it was observed that the reinforced composite with two fibres (modal + polyester) presented better results in comparison to the other two composites both in the tension/extension as well on the three point bending tests. In the water absorption test, it was possible to observe an equilibrium in the water absorption by the modal and polyester composite, due to the union of the two fibres. In the SEM images, the regions of rupture in the composites as well as the adsorption between the fiber and the matrix could be observed

Estudo da desidratação de tomates em pedaços com pré-tratamento osmótico

Vegetables drying plays an important role in the field of food dehydration, being a very old practice that was originated from sun drying items of food in order to preserve them to be consumed during the periods of scarcity. One of these vegetables is the tomato, that was originally grown in South America. Tomatoes are easily perishable after being picked up from the tree and this makes the process of tomato dehydration a challenge due to the high amount of water (95%) contained in them. The present research work was mainly intended to develop alternative processes for tomato conservation, by drying slices of skinned and unskinned tomatoes in the in natura form or in the osmotically pre-dehydrated form. Firstly, the best conditions of the osmotic pre-dehydration process were defined including temperature, immersion time and concentration of the osmotic solution, based on the results of water loss, solids gain and weigh reduction of the pre-dehydration tomatoes at different processing conditions. The osmotic solution used was made up of NaCl (5 and 10%) and sucrose (25 and 35%) at different combinations. For a fixed conditions of osmotic pre-dehydration, the drying tests of the pre-processed and in natura tomatoes were carried out in a stove with air circulation and a convective dryer with trays, at two levels of temperature. The sensorial analysis of the osmotically pre-treated and unskinned dehydrated tomatoes was carried out as well as a study on the their shelf-live. The results obtained showed that the drying of the tomatoes took place as a result of the internal control of the water transport, and did not show a constant rate, while two distinct periods of the decreasing phase were observed. The osmotic pre treatment substancially reduced the initial amount of humidity in the tomatoes, thus reducing the necessary time for the product to attain levels of intermediate humidity. The impermeability of the tomato skin was identified as well as the unfavorable influence of the pre-treatment on the unskinned tomatoes, whose solid gain brought about a decrease in the water activity with subsequent reduction of the drying rate. Despite the various simplifications carried out during the development of this study, the proposed diffusive model adjusted to the experimental data satisfactorily, thus making it possible to determine the effective coefficients of diffusion, whose results were consistent and compatible with those found in the current literature. Concerning the higher rates of evaporation and the lowest processing time, the best results were obtained in the drying of the unskinned, in natura tomatoes and of the skinned, pre-dehydrated tomatoes, at 60ºC, both processed in the convective drier. The results of the sensorial analysis of the unskinned and pre-treated product did not prove to be satisfactory. Regarding the shelf-live of the tomatoes, for a period of 45 days, no physicochemical or microbiological alteration of the product was noted