Navegando por Data de Publicação, começando com "2016-04-08"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 7 de 7

Cultivo de Chlorella vulgaris em diferentes concentrações de vinhaça e fontes de luz
(Universidade Federal de São Carlos, 2016-04-08) Souza, Andréa Cristina Moralez de; Lombardi, Ana Teresa; https://lattes.cnpq.br/6737850858443813; https://lattes.cnpq.br/1818385536348054
The effluent from the sugarcane (sugar and ethanol) industry known as vinasse presents high content of organic matter and nutrients that can be used in the cultivation of microalgae with the advantages of low cost and reuse of byproducts. This work proposes to investigate the best cultivation condition of Chlorella vulgaris (BEYERINCK, 1890) in agroecological vinasse treated and diluted in concentrations from 10% to 60%. It is noted that the vinasse carries microorganisms as bacteria and yeasts, and despite previous treatment of algal cultures, other microorganisms were always present. For algal growth, we initially tested different light sources (fluorescent, hot white LED and hot white with red LED). It was guaranteed the same light intensity (120μmols m 2s-1) for any of the vinasse concentrations. It was assessed the algal cell density, the pH and conductivity over 96 hours. The best result for growth of C. vulgaris was obtained in vinasse 20% in the presence of hot white and red LED with a growth rate (1.45 d-1), higher than the control (1.29 d-1). In a next step it was performed the microalgae cultivation in the best condition tested (20% vinasse) to evaluate the photosynthetic and biochemical parameters of biomass produced in addition to the physicochemical characterization of vinasse before and after cultivation. The results showed a reduction of the photosynthetic efficiency and chlorophyll concentration during the experimental period, suggesting mixotrophic metabolism possibly due to the presence of organic carbon. We observed that the biomass production was 40% higher in the vinasse in culture as compared to the control. The production of proteins and fatty acids was also higher in the biomass held in vinasse than in the control. The cultivation of the organisms led to a significant reduction of nitrogen levels (98%) and potassium (70%) in organic vinasse. This research has shown that microalgae cultivation in vinasse reduced the nutrient content of the residue, this factor has high impact when discarded in the environment and produced a biomass with high protein content and the presence of fatty acids that confer high commercial value, it can be investigated for the production of animal feed. The academic experience related to this study was also contributor of formal education in high school from a public school.
Desenvolvimento de um ensaio mecânico não convencional para a análise da relaxação de tensões do politetrafluoretileno
(Universidade Federal de São Carlos, 2016-04-08) Melo, Caiuã Caldeira de; Canto, Rodrigo Bresciani; https://lattes.cnpq.br/1316268411830615; Canto, Leonardo Bresciani; https://lattes.cnpq.br/7287108960864123; https://lattes.cnpq.br/1098228832866096
The mechanical behavior of materials usually depends on room temperature and loading rate. The identification of the time-dependent mechanical behavior is a great difficulty for the industry in the application of new materials such as polymers, mainly for long-term behavior. In this context, several experimental apparatus for measuring mechanical properties of long-term behavior have been developed. Generally, these devices are expensive and its use is unique to a specimen tested at one time. This study is a development of a new technique and methods for the characterization of time-dependent mechanical behavior in longterm tests. The hole-shaft coupling test (HSCT) was developed to the low cost of implementation and, especially, not a continued occupation of a testing machine for long periods, allowing the performance of more than one test at the same time. The HSCT results revealed the stress relaxation effects on polytetrafluoroethylene over several days. An optimization with finite element (FE) simulations assistance was carried out to characterize the viscoelastic material and obtain Maxwell generalized model parameters, an analytical formulation was also performed. Additionally, the strains were measured during recovery of the material by digital image correlation (DIC). The HSCT proved to be feasible for measuring the long-term stress relaxation, demonstrating the advantages mentioned above. The FE simulations reproduced qualitatively the mechanical behavior of the material, as well as the analytical model developed. Measurement of strain recovery after HSCT via DIC is presented a way to enrich the characterization of the material.
Relações humanas com a água : percepção ambiental, saberes tradicionais, simbolismos culturais e contribuições para a gestão e conservação da água
(Universidade Federal de São Carlos, 2016-04-08) Dictoro, Vinicius Perez; Hanai, Frederico Yuri; https://lattes.cnpq.br/7651828454575175; https://lattes.cnpq.br/9469471717661914
For many centuries, mankind has considered fresh water as inextinguishable feature, without evaluating the environmental consequences related to quantity and quality. The current form of appropriation of water to meet the high demand of the various uses of water resources by the company has configured intense transformations in human relations with the water. In the old days, companies had other complementary visions to the direction of the water deities, bows and very natural available both for human existence and other species, as to the balance and maintenance of ecosystems. Therefore, human relations with the water permeate this relationship of utilitarian sense, only for economic purposes and survival, and configure other relationships as: religious, cultural, symbolic and emotional. In this way, the overall objective of the research was to identify and analyze different human relationships with water, seeking to understand the varied forms of recovery of water, and also to analyze the current model of water management through National Water Resources Policy instruments, for the purpose of providing subsidies that may assist in the consideration of human relationships with water in its management and conservation. This was followed by work based on qualitative research and case study was developed in two distinct audiences, residents of Pirapora-MG, situated on the banks of the São Francisco River, and members of river basin committees. The data were collected through interviews and questionnaires. Symbolic, cultural relations were identified, mystical and local knowledge, affective of individuals with the water. These aspects should be transmitted in new forms of awareness for the management and conservation of water. It is necessary to step up the way of acting on awareness, promote new programs and new actions with the purpose of expanding the vision centered on Man and on their anthropogenic activities, enabling a rescue of cultural symbolism of the water and the various relationships and appreciation that it has with society.
Secagem de materiais têxteis
(Universidade Federal de São Carlos, 2016-04-08) Caneda, Chaiane Messa; Ferreira, Maria do Carmo; https://lattes.cnpq.br/7070885875161111; https://lattes.cnpq.br/5288147854256960
The fabrics are derived from fibers, which are divided into to main groups: natural (like cotton) and chemical (such as rayon and polyester). In the processing of the fabric, drying is a major operation, contributing to the finishing and obtaining a fabric with greater brightness and also better touch. However, each tissue has a different structure and different composition which can influence its absorption capacity and retention of water. The aim of this study is to analyze the drying of 3 types of fabrics (polyester, toweling and jeans), and evaluate how the material characteristics and operating conditions influence the process. Experimental tests were conducted in oven with natural convection, with natural convection, at temperatures of 50, 60 and 70 ° C and also in a tunnel dryer with forced convection under the conditions of 1.0 and 2.0 m / s at the temperatures of 50, 60 and 70 ° C. Besides that, the adjustments of generalized curves of drying were evaluated, there are empirical equations of kinetics. In the evaluation of water absorption in saturated atmosphere at 40 to 60 ° C, it was observed that the polyester is the fabric that absorbs less water while the jeans had greater absorption capacity. It was also found that absorption increases with increasing temperature for all three fabrics. By analyzing the influence of operating conditions on the drying fabrics, the air speed was the variable that most influenced the moisture reduction, indicating that surface resistance was the limiting mechanism in drying. Page model (1949), was the most appropriate to represent the generalized kinetic curves for the fabrics evaluated.The comparative analysis of the fabrics showed that, although significant differences in the type of fiber and fabric structure, these characteristics do not influence the drying of the material, indicating that the drying of materials with high surface area, the process is controlled by the conditions flow.
Estudo do pré-tratamento hidrotérmico e hidrólise enzimática da palha de cana-de-açúcar
(Universidade Federal de São Carlos, 2016-04-08) Souza, Renata Beraldo Alencar de; Cruz, Antonio José Gonçalves da; https://lattes.cnpq.br/1812806190521028; https://lattes.cnpq.br/8409898535548523
The complex cell wall structure of lignocellulosic biomass makes pretreatment one of the most relevant 2G ethanol production process steps due to the difficulty of hydrolyzing lignocellulose to fermentable sugars and the cost of the process as a whole. The optimization of enzymatic hydrolysis conditions is crucial for reaching high yields that make the process feasible. In this way, the aim of this work is to assess the stages of pretreatment and enzymatic hydrolysis of the cellulosic fraction of straw sugarcane. All samples were chemically characterized before and after the pretreatment step. Hydrothermally pretreatment was evaluated in four conditions: 170ºC / 5 min, 170ºC / 15 min, 220°C / 5 min, 220°C / 5 min, and 195ºC / 10 min. Higher hemicellulose removal (85.58%) was found at 195ºC / 10 min. This operational condition was set as a reference. Hydrolysis experiments were carried out in Erlenmeyer flasks at 50ºC, 250 rpm and pH 4.8, with a reaction volume of 50 mL. Two sets of experiments were performed. In the first, the effect of substrate concentration was evaluated varying solid load (5; 10; 15; 20% msolid/vsolution) with enzyme load constant in 13 FPU.gbiomass. At 72h of enzymatic reaction, cellulose conversions were: 72% (5% of solids), 84% (10% of solids), 72% (15% of solids), and 59% (20% solids). In the second set, the enzyme (Cellic®CTec2) load effect (3; 7; 10; 13; 16; 40 FPU/gbiomass) with solid load settled at 15% (msolid/vsolution), was assessed. For assays with 15% of solid load, cellulose conversions were: 48% (3 FPU/gbiomass), 58% (7 FPU/gbiomass), 66% (10 FPU/gbiomass), 72% (13 FPU/gbiomass), 71% (16 FPU/gbiomass), and 74% (40 FPU/gbiomass). A trade-off between solid load and enzyme dosage was found (15% m/v and 13 FPU/gbiomass) which results in 72,4% of cellulose to glucose conversion. After that it was studied the products inhibition effect on hydrolysis was assessed. glucose and cellobiose (10 and 30g.L-1) caused a higher inhibitory effect. Xylose did not show the significant inhibitory effect on β-glucosidase. However, glucose and cellobiose had significant inhibitory effects on endoglucanase and exoglucanase as well as on β-glucosidase. Hydrolysis experiments were conducted in the batch reactor (3 L) with 10% solids to compare the performance with the hydrolysis conducted in Erlenmeyer flasks. At 72h hydrolysis cellulose to glucose, conversion was obtained in 84.8% (Erlenmeyer flask) and 80.2% (in the reactor); hydrolysis profiles obtained were similar in both conditions evaluated. In face of this, it was opted by conduct experiments in bioreactor (50 mL) using solid loads of 15 and 20% showed the best cellulose to glucose conversions when compared to those carried out in shake flasks in the same conditions.
Influência do tamanho médio de grão nas propriedades ferroicas de compósitos magnetoelétricos particulados
(Universidade Federal de São Carlos, 2016-04-08) Viana, Diego Seiti Fukano; Garcia, Ducinei; https://lattes.cnpq.br/5236758856687873; https://lattes.cnpq.br/3547492755324499
In the case of composites materials, which presents the magnetoelectric coupling, there are so many questions about the influence of the microstructure on the coupled and uncoupled properties. Thereby, this work proposes the study of the grain size influence, of ferroelectric and magnetic phases, on the magnetic, electric and coupled properties in particulate magnetoelectric composites. In order to study the relationship property/microstructure in volumetric magnetoelectric composites, it was necessary to prepare samples with different average grain sizes, ie, the phases having average grain size in the order of micrometers or nanometers. To perform this study it was used as magnetic phase the CoFe2O4 and, as the ferroelectric phase, the [0,675] Pb(Mg1/3Nb2/3)O3 – [0,325] PbTiO3, mixed in molar ratio 20/80 %, using techniques like micro ball milling (to reduce particle size) and high energy ball milling (to mixture the phases) during the powder syntheses, and Spark Plasma Sintering (SPS) to densify the bulk. Due the presence of secondary phases in sintered composites generated during the application of SPS, a processing protocol was created based on a post sintering thermal treatment, in PbO rich atmosphere, which allowed the reduction of secondary phases without, however, changing the average size of grain. These procedures resulted in composite material suitable for the investigations of the electrical, magnetic and magnetoelectric properties, considering the different microstructures obtained. The magnetoelectric composites showed the self-biased effect arising from the intrinsic strain generated in one phase over the other. It was observed the properties dependence, coupled or uncoupled, with average grain size of both phases. Furthermore, the magnetoelectric composites presented the selfbiased effect that appears due to intrinsic strain generated from one phase over the other. Moreover, the evolution of the magnetoelectric coefficient behavior as a function of temperature and applied magnetic field has been more dependent on the variation of the average grain size of the ferroelectric phase than the ferrimagnetic phase, which can be attributed to the largest amount of ferroelectric phase in the structure compound.
Envolvimento dos trabalhadores em grupos de melhorias : estudos de caso sobre o seis sigma
(Universidade Federal de São Carlos, 2016-04-08) Zanca, Camila Garcia; Rachid, Alessandra; https://lattes.cnpq.br/6981682198988902; Donadone, Julio César; https://lattes.cnpq.br/7643906508178259; https://lattes.cnpq.br/7001692487030687
This study aims to understand how Six Sigma has been appropriated by companies, considering the involvement of blue collar workers in improvement teams, its composition and objectives prioritized by the method approaches in companies. Quality methods, especially those related to Japanese model, such as Total Quality Management, recommend the involvement of workers. Six Sigma, latest diffusion method, has particular regard to the organization of work, marked by studies that identify a more limited involvement than recommended by manuals Six Sigma and compared the quality methods used in the past. For its pioneering adoption of management practices, consisting of reference even for other sectors, the automotive sector was chosen to conduct the research, specifically the auto parts segment. In view of different uses of quality methods by companies, five case studies were conducted, as well as analysis of previous survey and information gathered in telephone interviews with six other companies. It was identified that the involvement of workers occurs mainly in quality control and suggestion programs, whose different formats can promote varying levels of involvement. Involvement with Six Sigma, in turn, is restricted to the collection of information for improvements. It is less likely workers were involved in the decision of the improvements to be developed and the full cycle of projects. The main reasons cited for not involve workers with Six Sigma were the complexity of statistical tools, the difficulties in giving training to workers and jobs cuts embedded in some improvements in the projects promoted. The company that promoted greater involvement has a consolidated experience in problem-solving teams, which joined the Six Sigma elements. This hybridization between methods was also observed in another participating company in relation to kaizen. A less significant involvement was observed in the company whose approach to Six Sigma is directed primarily to cost reduction. Since being acquired by a holding company, this company has restricted the participation of workers, signaling that the management of shareholders may be greatly influenced the organization of work, which is reinforced by the analysis of projects and implementation of Six Sigma in this company. The case studies contribute to the understanding of changes in work organization related to the spread of Six Sigma and the predominance of financial logic.