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Estudo de composições de amido termoplástico: extrusão reativa e nanocompósitos com microfibrilas de celulose
(Universidade Federal de São Carlos, 2012-09-28) Ferreira, Adriane de Medeiros; Carvalho, Antonio José Felix de; https://lattes.cnpq.br/5050955206618507; Gandini, Alessandro; Hui, Wang Shu
A resistência à tração, módulo de elasticidade e alongamento das amostras de TPS com o diisocianato, na presença ou ausência de ácido cítrico, e poli(isocianato) bloqueado na ausência de ácido cítrico, aumentaram em comparação ao TPS. Todos os materiais modificados quimicamente apresentaram redução na absorção de água após a modificação química. Observou-se um aumento na massa molar das amostras com quantidades menores de incorporação do diisocianato e poli(isocianato) sem ácido cítrico, resultado da formação de grupos uretana no material. As propriedades mecânicas dos nanocompósitos sofreram um significativo aumento na resistência e módulo de elasticidade se comparada ao TPS original. A adição de microfibrilas ocasionou um aumento da resistência mecânica dos nanocompósitos. The nanocomposites were prepared with nom modified thermoplastic starch reinforced with cellulose microfibrils obtained by alkaline treatment of eucalyptus pulp, followed by cryogenic grinding. The materials were characterized by infrared spectroscopy (FT), X-ray diffraction, dynamic mechanical analysis (DMA), liquid chromatography size exclusion high-efficiency (HPSEC), atomic force microscopy (AFM) microscopy, transmission and scanning (MTV-EGF), water absorption and mechanical tests. The use of single-screw extruder for the chemical modification of thermoplastic starch proved to be efficient because it promoted the reaction of diisocyanates in the presence or absence of citric acid. The process was also effective in decreasing the crystallinity of the TPS, which can increase its stability after processing. The tensile strength, modulus and elongation of TPS samples with the diisocyanate in the presence or absence of citric acid, and blocked polyisocyanate in the absence of citric acid increased after chemical modification by REX. For all chemically modified materials it was observed a decreased in the water absorption compared to the TPS. There was an increase in molar mass of the samples with smaller amounts of diisocyanate and polyisocyanate without citric acid, as a result of the formation of urethane groups in the material. The mechanical properties of nanocomposites underwent a significant increase in strength and elastic modulus when compared to the pristine TPS. The microfibrils addition causes an increase in the mechanical properties of the nanocomposites.
Estratégia de modelagem para controle de FMS combinando redes de Petri e um sistema Fuzzy
(Universidade Federal de São Carlos, 2012-09-28) Reis, Felipe Bezerra dos; Morandin Júnior, Orides; https://lattes.cnpq.br/4192845106907956; https://lattes.cnpq.br/8671794210173330
The flexible manufacturing systems (FMS) are automated production systems capable of producing a wide variety of product types. They are composed by machines, robots and automated transport systems. Make the control of an FMS is a complex task due to the various subsystems and elements that compose it, and also by the necessity of respond to strategic issues that vary according to market demands. Much has been made in relation to the control of FMS. Several studies in the literature cover issues of control of FMS. Despite the high number of papers that address these issues, technological advances and market demands cause introduction of new challenges and new studies are conducted. This work based itself on other studies about the control of FMS to evolve into some issues of modeling and control of FMS. The purpose of this paper is to indicate a modeling strategy, based on Petri nets, that is easy to understand, requiring low efforts to adapt to different production plans, and allowing that the control of the FMS model takes into account information of the current state of the system in decision making for conflict resolution. The work ends with the application of the modeling method proposed in a hypothetical FMS. It was built a control system to make the reading of variables from the model of the FMS and decide how conflicts should be resolved on the Petri net model. To support the decision making of the control system, it was built a Fuzzy system. Simulations were conducted for a variety of production plans in which the control system achieved real-time responses to conflict resolution, preventing the system of reach deadlock conditions.
Uma solução de roteamento para redes de sensores sem fio móveis heterogêneas
(Universidade Federal de São Carlos, 2012-09-28) Vilela, Mateus Aparecido; Araujo, Regina Borges de; https://lattes.cnpq.br/8964123297688432; https://lattes.cnpq.br/6329364737859244
The Wireless Sensor Networks (WSNs) and Mobile Wireless Sensor Networks (MWSNs) are being increasingly used by different applications, such as monitoring of animals, monitoring of vital signs, environmental monitoring, surveillance and protection of critical infrastructure, leaking gas, among many others. Some of these applications are already making use of mobile sensor nodes, such as underwater monitoring, precision agriculture, among many others. Due to restricted resources of sensor nodes, especially in relation to energy consumption, the development for solutions based on WSN and MWSN becomes limited. The use of mobile sensor nodes, which typically has more computational resources, power and communication, can help to reduce the energy consumption of fixed nodes, increasing the lifetime of the network. Networks that use mobile sensor nodes (fixed and mobile) with different types of hardware are called Wireless Sensor Networks Heterogeneous Mobile. This paper presents the RAHMoN (Routing Algorithm for Heterogeneous Mobile Networks), which makes use of data aggregation technique to reduce the traffic transmissions on the network, hierarchy of nodes (clustering), and use of sensor nodes (fixed and mobile) that collaborate to deliver data to a sink node at high speed. In RAHMoN, the network is configured using the techniques of inundation (flooding) and inundation reverse (reverse flooding) to collect the fixed position of sensor nodes and form an adjacency matrix. This matrix helps to build routes for data delivery to the sink and is stored in the mobile sensor nodes. Results show that our solution can guarantee a high packages delivery rate, low latency and reduce the delay of packet delivery. The solution was compared with the WHISPER, present in the literature and also focused on the delivery of data to sink node at high speed.
A agrobiodiversidade nas terras indígenas guarani Nhandewa no norte do Paraná: memória, resgate e perspectivas
(Universidade Federal de São Carlos, 2012-09-28) Almeida, Thiago Valente Vieira de; Norder, Luiz Antonio Cabello; https://lattes.cnpq.br/0080353709980071; https://lattes.cnpq.br/3306060519945768
The importance of the farmers themselves hold their traditional varieties of seeds becomes even more relevant to indigenous peoples, both for the richness of ethnic knowledge developed, and the rescue of these practices in the current context of degradation and erosion of diversity, imposed by the dominant monocultural model. This study characterized the situation of indigenous agrobiodiversity in the north of Paraná state, indigenous territory Terra Indígena Laranjinha and Terra Indígena Pinhalzinho , inhabited by Nhandewa Guarani Indians. Through an ethnographic study examined the memory of the Guarani Indians of their various tradicional seeds, their distinct characteristics and uses, as well as agricultural practices were employed by ancians. The wishes of indigenous agrobiodiversity rescue and the difficulties facing the dominant model of production in the field were also registered. Terra Indígena Pinhalzinho performed the first Feira de Troca de Sementes Crioulas/Tradicionais and directed efforts to locate and produce the varieties of rice, beans, potatoes, cassava and maize indigenous. Respondents shall ensure that the presence of these seeds help to rescue cultural universe, strengthening spiritual Guarani lifestyle.
Um estudo de aspectos do sistema solo planta a partir de uma abordagem investigativa no ensino de química
(Universidade Federal de São Carlos, 2012-09-28) Silva, Marta da; Marques, Clélia Mara de Paula; https://lattes.cnpq.br/0451284088402660; https://lattes.cnpq.br/4613115707801181
The school is the privileged place for the process to the teaching and learning of the Chemistry contents to happen in the significative way. In this process, is the basic that the student interest of these contents mediated of the educator. This interest should lead the student to involve in the actives proposed by the teacher, which will result in the development of cognitive skills. The experimental investigative activity has been defended by researchers as a system that can help to motivate the students to learn chemistry and also provide skills development. Considering this context, this research have aimed to effect and evaluate learning acquired by students in a class of 1.st year of high school actives from experimental investigations on aspects of soil plant system. The data collection was effected in three stages: questionnaire previous, experimental investigative activity (level 1), that approached the conductivity of matters and experimental investigative activity (level 2) with the following theme: Some aspects of soil plant system from the development of the species growing vegetables that Rabish and rocket. The experimental actives were planned according to the class suggested by (TAMIR, 1991; PELLA, 1961). The concepts covered were: solubility, soil composition, chemical species and ions. The work was done with the contents from problem situations proposed by the teacher. The students worked in groups, raised hypotheses, experiment of the solutions that could confirm their hypotheses. For the record of their actives, the students used the board diary. For data analysis, the questionnaires and the board s diary were collected and analyzed qualitatively by defining categories. To the from these analysis it was observed that the use of experimental actives with investigative character joined with thematic soil plant, provided the context of chemical concepts. The students acquire learning and skills developed conceptual, proceeding and attitudinal. The involvement of the students during this project and the development of skills intensify the importance of using experimental investigative actives in the teaching of chemistry.
Produção de lipopeptídeos e glicolipídeos a partir da bioconversão do co-produto da produção do biodiesel
(Universidade Federal de São Carlos, 2012-09-28) Sousa, Juliana Rabelo de; Cruz, Antonio José Gonçalves da; https://lattes.cnpq.br/6996468259530844
Biosurfactants are a surface-active chemical compounds synthesized by microorganisms. These compounds have many advantages when compared to their chemically synthesized counterparts as specific action, low toxicity, higher biodegradability, effectiveness at extreme temperatures, pH and strength ionic. They appear as promising candidates to replace chemical surfactants produced from petrochemicals. The use of renewable and low cost substrates such as agro based industrial wastes is one of the attractive strategies for economical large scale biosurfactants production. In this work, it was evaluated glycerol, a co-product of biodiesel production, as carbon source for biosurfactant production. Two microorganisms, Pseudomonas aeruginosa MSCIC02 and Bacillus subtilis LAMI009, both isolated from environmental sources, were used thorough this work. In the first part of the work experiments were carried out in shake flasks using P. aeruginosa. The results showed that the increase in nitrogen source (sodium nitrate) and the decrease in the carbon source (glycerin) favored rhamnolipids production. In the range studied, the maximum biosurfactant concentration obtained was 2.3 g⋅L-1 (C/N ratio 12). The effect of nitrogen concentration on the biosynthesis of rhamnolipids and pH behavior as a function of the nitrate concentration in the cultures indicated that this strain probably carried a denitrification route favoring the production of rhamnolipids. Experimental runs carried out in bioreactor indicated that the integrated process of production and separation/concentration by fractionation in bubble column equipment caused many operation problems, such as the drag cell, and reducing the concentration of rhamnolipids to 0.4 g⋅L-1in the reaction medium. The kinetics of product formation was evaluated by two models. The Luedeking-Piret model was not able to represent the process. The model proposed by MERCIER et. al. (1992) could adequately describe the rhamnolipids production from P. aeruginosa strain. Emulsifying capacity of the cell-free culture medium was assessed by the emulsification index (EI24). The biosurfactant produced was able to emulsify vegetable oils as well as mineral oils. EI24 greater than 55% was reached. In the second part of the work experimental data from Bacillus subtilis LAMI009 cultivated in shake flasks showed that the growth of this strain was dependent on iv the medium supplementation with yeast extract. A change in culture medium was implemented in order to reduce the length of the lag phase. The use of inorganic nitrogen sources showed that both ammonium nitrate and ammonium sulphate reached similar values of surfactin concentration and volumetric productivity. It was obtained 35 mg⋅L-1 and 6.1 mg⋅L-1⋅h-1, respectively. Surface tension of the cell-free culture medium was similar for both nitrogen sources. The minimal value obtained was 29.7 mN⋅m-1. Sodium nitrate was found to be an adequate nitrogen source for cell growth. However, in these assays low productivity and low surface tension reduction were obtained when compared to the other nitrogen sources evaluated. The supplementation of the culture medium with yeast extract improves the surfactin concentration (60.0 mg⋅L-1) and volumetric productivity (5.2 mg⋅L-1⋅h-1). In this assay the surface tension reached 28.1 mN⋅m-1. The inoculum size had a great influence on cell growth and production of surfactin. When 2% (v/v) of inoculum was used the surfactin concentration and volumetric productivity obtained were 148.2 mg⋅L-1 e 14.22 mg⋅L-1⋅h-1, respectively. The search for genes responsible for production of lipopeptides surfactin and iturine indicated the presence of the genes lpa14 and ituD in B. subtilis LAMI009 genome. Analysis of the chromatography profile of methanol extracts of the lipopeptides from culture medium with ammonium nitrate and sodium nitrate as nitrogen source showed characteristic peaks of the surfactin and iturine. Thereby, it is believed that this strain is a co-producer of both surfactin and iturine. Emulsifying capacity of the cell-free culture medium showed higher stability with the media that employed ammonium nitrate and sodium nitrate as nitrogen source. It was obtained EI24 of 65% with n-hexadecane and 45% with kerosene. The acid precipitation of biosurfactant from the cell-free culture medium showed that this prepurification step promoted an increase in the emulsifying capacity of the mixture of lipopeptides synthesized by B. subtilis LAMI009. The aqueous solution of crude biosurfactant was able to emulsify naphthenic oils, vegetable oils, and an aromatic hydrocarbon. Values of EI24 greater than 65% were obtained. Emulsions formed with naphthenic oils were more stable according to droplet-size distribution. The smaller the size of droplets, the more stable was the emulsion.