47 resultados para 10121028 TM-40
Resumo:
The metabolic syndrome (MetS) involves a group of risk factors and is associated with a significantly higher risk of developing cardiovascular diseases (CVD) and type 2 diabetes. Recent studies have shown the importance of preventing CVD through early diagnosis and treatment of patients with MetS. The objective of our study was to determine the prevalence of MetS by different diagnostic criteria in postmenopausal women and analyze the influence of socioeconomic factors on cardiovascular risk in this sample of the population. A cross-sectional study involving 127 postmenopausal women (45 to 64 years) from Natal and Mossoró, Brazil. The study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte. The experimental protocol consisted of applying structured interview, clinical examination and implementation of dosages blood. The diagnosis of MetS was based on NCEP-ATP III (National Cholesterol Education Program-Adult Treatment Panel III) and IDF (International Diabetes Federation) criteria. The research was accomplished with the participation of an interdisciplinary team in their several phases. The result of the sample studied had mean age of 53.9 ± 4.6 years and per capita income of 54.5 dollars. The prevalence of MetS, according to NCEP-ATP III and IDF criteria, was 52.8% and 61.4$, respectively. The agreement rate between NCEP-ATP III and IDF criteria was 81.9%, with a kappa value of 0.63 (CI 95%, 0.49-0.76), indicating good agreement between the two definitions. The most prevalent cardiovascular risk factor was HDL < 50 mg/dl, observed in 96.1% of the women analyzed, followed by increased waist circumference (≥ 80 cm) in 78.0%, elevated blood pressure in 51.2%, triglycerides ≥ 150 mg/dl in 40.9% and glycemia ≥ 100 mg/dl in 37.0% of the women. The occurrence of MetS was significantly associated with schooling and body mass index (BMI). High blood pressure was significantly associated with low family income, low schooling and weight gain. There was no significant association between the intensity of climacteric symptomatology and the occurrence of MetS. The conclusions of the research were that MetS and its individual components show a high prevalence in postmenopausal Brazilian women, and significant associations with weight gain and low socioeconomic indicators. The data point to the need for an interdisciplinary approach at the basic health care level, directed toward the early identification of risk factors and the promotion of cardiovascular health of climacteric women.
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Heart transplantation (HT) represents one of the greatest advances in medicine over the last decades. It is indicated for patients with severe heart disease unresponsive to clinical treatment and conventional surgery, poor short-term prognosis and a 1- year mortality rate over 40%. HT has improved survival worldwide (80% in the first year, 70% in five years and 60% in ten years). However, the procedure has been associated with weight change and increased risk of secondary conditions such as diabetes, hypertension, dyslipidemia and obesity due to immunosuppressive therapy following transplantation. The objective of this study was to determine the impact of weight change on the metabolic stability of HT patients. The study was retrospective with data collected from the records of 82 adult patients (83% male; average age 45.06±12.04 years) submitted to HT between October 1997 and December 2005 at a transplantation service in Ceará (Brazil). The selected outcome variables (biopathological profile, weight and body mass index―BMI) were related to biochemical and metabolic change. The results were expressed in terms of frequency, measures of central tendency, Student s t test and Pearson s correlation coefficients. The analysis showed that following HT the average global BMI increased from 23.77±3.68kg/m2 to 25.48±3.92kg/m2 in the first year and to 28.38±4.97kg/m2 in the fifth. Overweight/obese patients (BMI ≥ 25 kg/m2) had higher average levels of glucose, total cholesterol, low-density lipoprotein and triglycerides than patients with eutrophy/malnutrition (BMI < 25 kg/m2). In conclusion, overweight/obese patients were likely to present higher average levels of glucose, triglycerides, total cholesterol and fractions than patients with eutrophy/malnutrition, indicating a direct and significant relation between nutritional status and weight change in the metabolic profile of HT patients
Resumo:
Com a criação dos Parâmetros Curriculares Nacional (PCNs), a saúde passou a ser um tema transversal que deve ser trabalhado por todos os níveis de ensino em toda a escola, principalmente pelos professores do ensino fundamental, os quais têm uma grande responsabilidade no processo de formação dos valores e de condutas dos escolares. Com o objetivo de investigar a concepção dos professores de ensino fundamental (1ª a 4ª séries) sobre a saúde do escolar, este estudo teve como amostra 45 professoras lotadas em 04 escolas públicas e 04 escolas privadas no município de Natal/RN. Para a coleta dos dados foi utilizado um questionário semi-estruturado, sendo os mesmos analisados por meio da análise temática. A faixa etária com maior prevalência foi a superior a 40 anos, com 58% de professoras. Com relação ao grau de formação acadêmica das docentes investigadas, 47% delas tem o terceiro grau completo e, 40% possuem apenas formação no magistério. No que se refere ao tema transversal saúde, 27% das professoras não realizaram estudos sobre o mesmo e, 40% das docentes não se sentiam preparadas para desenvolver esse conteúdo, apontando como principal fator limitante à falta de conhecimento mais profundo sobre saúde e a falta de material didático adequado. Sobre a importância em se trabalhar a saúde, 29% das respostas referiram-se aos cuidados com a saúde, e 20% em prevenir e conhecer doenças. Pode-se concluir que é necessária uma capacitação específica referente à temática em questão, o que deve ser acompanhada de políticas públicas que incentivem o profissional da educação e ofereça estrutura ao ambiente escolar
Resumo:
Colon-specific drug delivery systems have attracted increasing attention from the pharmaceutical industry due to their ability of treating intestinal bowel diseases (IBD), which represent a public health problem in several countries. In spite of being considered a quite effective molecule for the treatment of IBD, mesalazine (5-ASA) is rapidly absorbed in the upper gastrointestinal tract and its systemic absorption leads to risks of adverse effects. The aim of this work was to develop a microparticulate system based on xylan and Eudragit® S- 100 (ES100) for colon-specific delivery of 5-ASA and evaluate the interaction between the polymers present in the systems. Additionaly, the physicochemical and rheological properties of xylan were also evaluated. Initially, xylan was extracted from corn cobs and characterized regarding the yield and rheological properties. Afterwards, 10 formulations were prepared in different xylan and ES100 weight ratios by spray-drying the polymer solutions in 0.6N NaOH and phosphate buffer pH 7.4. In addition, 3 formulations consisting of xylan microcapsules were produced by interfacial cross-linking polymerization and coated by ES100 by means of spray-drying in different polymer weight ratios of xylan and ES100. The microparticles were characterized regarding yield, morphology, homogeneity, visual aspect, crystallinity and thermal behavior. The polymer interaction was investigated by infrared spectroscopy. The extracted xylan was presented as a very fine and yellowish powder, with mean particle size smaller than 40μm. Regarding the rheological properties of xylan, they demonstrated that this polymer has a poor flow, low density and high cohesiveness. The microparticles obtained were shown to be spherical and aggregates could not be observed. They were found to present amorphous structure and have a very high thermal stability. The yield varied according to the polymer ratios. Moreover, it was confirmed that the interaction between xylan and ES100 occurs only by means of physical aggregation
Resumo:
Compounded medicines have been reported by the ANVISA due to decreased of the therapeutic response or toxicity of these formulations. The aim of this work was to investigate the physicochemical quality control among naproxen sodium oral suspensions 25 mg/mL obtained from six compounding pharmacies (A, B, C, D, E and F) and the manufactured suspension (R). In the quality control test, the tests of pH, content, homogeneity, volume and physical and organoleptic characteristics were performed according to the Brazilian Pharmacopoeia. The analytical method for determination of naproxen in suspensions was validate. This method showed excellent precision, accuracy, linearity and specificity. In the content test the suspensions B, C and E showed lower value and the F suspension showed a high value of the content. The products C and E were disapproved in the description of the physical and organoleptic characteristics test. In the pH test, three suspensions were outside specifications (C, E and F). Only the products R, A and D showed satisfactory results in these tests and therefore they were approved for relative bioavailability test. The R, A and D suspensions were orally administered to Wistar rats and the blood samples were taken at time intervals of 10, 20, 40, 60 min, 3, 4, 6, 24 and 48 h. The plasma samples were immediately stored at 80 ºC until analysis of HPLC. The bioanalytical method validation showed specificity, linearity (R2 0.9987), precision, accuracy, good recovery and stability. The chromatographic conditions were: flow rate of 1.2 mL.min-1 with a mobile phase of acetonitrile : sodium phosphate buffer pH 4.0 (50:50, v/v) at 280 nm, using a C18 column. The confidence interval of 90% for the Cmax and AUCt ratio was within the range of 80 - 125% proposed by the FDA. Only one suspension, obtained from the compounding pharmacy D, was considered bioequivalent to the rate of absorption under the conditions proposed by this study. Thus, the results indicate the need for strict supervision from the relevant authorities to ensure the patient safety and the quality of compounded drugs by pharmacies
Resumo:
The present study analyses non obligatory and remunerated traineeships in nursing, as a contribution to work process in health and learning of students at nursing technician courses. It objectives to examine the contribution of medium level nursing students on scholarships at a teaching hospital s work force, at Natal/RN. It s a quantitative/qualitative, that uses descriptive statistics and analysis fulfilled with categories that emerged from research, through a dialog between the studied authors in the theoretical reference of nowadays work process, work force, non obligatory and remunerated traineeships, and night shifts. The collaborators of this research were 105 (73,43%) nursing technicians, medium level students on scholarships that fulfill remunerated traineeships at the hospital. The feminine gender was a major part of the collaborators, with 90 (85,70%), in which medium age was 29,71 years, 62 (59,00%) single, 57 (54,30%) don t have kids, 100 (95,23%) students on scholarships with complete medium level, 78,10% with professional experience before their insertion at the remunerated traineeships, 73 (69,50%) referred to enjoy the area, reason for the nursing technician course choice. About the technician course conclusion, 83 (79,00%) affirmed that happened between 2005 and 2008, and about traineeships time in the institution, 38 (36,20%) have between one and six months. About learning, 74 (70,50%) referred to learn with the nursing technicians and all fulfilled specialized courses, or grade up to bond with the school and be able to be trainees. These courses were considered low quality ones, what justifies the number of 54 (51,40%) students with scholarships that said their performance in studies is good and 75 (71,40%) are able to join it with the traineeships without problems. About remuneration as scholarship, 71 (67,60%) referred that helped to keep up with the studies, because this amount has specially this purpose, paying studies. About nonobligatory traineeships, the ABEn-RN affirmed that there s no following process to this traineeship mode, as long as there was never this concern, because obrigatory traineeships demand a lot of the efforts in the meetings. And COREN-RN doesn t supervise this way of contract. The present research observed that there is, in fact, a contribution of medium level nursing students on scholarships work force on the researched institution. Resigned to work circumstances established by the institution, representing the lack of human resources, materials, work conditions, and work insertion in night shifts, it s possible to affirm that the situation is irregular about the students on scholarships, besides the determinant risk factor to their lives and health. In addition to it, the students on scholarships, in order to maintain the quality of trainee in the institution, are obligated to fulfill courses to grade up, or specialized courses in nursing technician, at schools referred as bad quality ones
Resumo:
This study is an exploratory descriptive study with a quantitative approach. The objective was to identify the actions for the early detection of breast cancer conducted by the health professionals of the Family Health Strategy in the Trairi region of the State of Rio Grande do Norte, Brazil. The research was conducted in nine municipalities of the region. Data were collected by means of a questionnaire with 52 Family Health Strategy professionals, 30 nurses and 22 physicians, that work in the region. Analysis was conducted using descriptive statistics. The results were organized and discussed in three areas: Knowledge about the early detection of breast cancer; Actions for early detection detection of breast cancer, and Difficulties experienced in the screening actions for breast cancer. The results indicate that these professionals (100%) have knowledge of the signs and symptoms of breast cancer and that the majority (96,2%) conduct screening actions in accordance with the recommendations of the Ministry of Health. However, a considerable number (55,8%) of these professionals encounters difficulties while conducting the screening procedures in his work setting. The difficulties varied from those of a personal nature to those of access to the procedure, such as the unavailability of sufficient quotas of screening exams. We conclude that the majority of health professionals execute the screening actions for breast cancer in their work settings according to the recommendations of the Ministry of Health, even though they encounter difficulties in the conclusion of the mammography and ultrasound exams, essential procedures in the early detection of breast cancer. We understand that these professionals demonstrate knowledge of secondary prevention even though they do not execute all the actions necessary for early detection primarily because they are impeded by the blockage of access to exam quotas. We conclude that, in spite of the difficulties experienced, the procedures for the early detection of breast cancer are being executed by the majority of the Family Health Strategy professionals in the Trairí region, specifically the clinical examination of the breast, orientation of breast self examination, requests for mammography and ultra sound examinations. Measures are needed that can mediate the difficulties, that will permit the realization of secondary prevention procedures with the population at risk in the region. We suggest training and actualization courses on the complete screening process that includes a wide discussion of the new legislation that provides the mammography exam for women over 40 years. We believe that the acquisition of such a work perspective for the early detection of breast cancer, along with knowledge of health vigilance and of breast cancer, will enhance integral health care of women that constitutes an aim of the nurse and the family health team
Resumo:
The psychiatric care and mental health are undergoing constant change over the History. The Brazilian Psychiatric Reform, which brings up the deinstitutionalization as a structuring in the restorative care process. The Reform has as one of the mainly substitutive services the Centers for Psychosocial Care (CAPS), which work from the Singular Therapeutic Project (PTS) in order to restore the autonomy and restore the dignity of users. The therapeutic workshop is some of the resources used and work several kinds of activities as: writing, handcraft, music, poetry, and so forth. This study set up to apprehend the social representations of helping of the music workshop carried out in the CAPS II east of Natal/RN, from the reports given by the participants of the workshop, using the focal group as technique. This is a descriptive exploratory study with a qualitative approach. A total of 16 users participated in four musical therapeutic workshops from April to May 2010. The study was approved by the Ethics and Research Committee of UFRN. The discursive material from the workshop was submitted to the informational resource of Analyse Lexicale par Contexte d um Ensemble de Segments de Texte, ALCESTE, and analyzed based on the Theory of Representations and the Central Core Theory. The majority of subjects were men (62.5%), single (62.5%), aged 40-49 years (37.6%) and elementary school level (56.2 %). The reports were transcribed and submitted to the classification system of ALCESTE, which elected the following categories: Category 1 - Experience in the Word Family Sung, Category 2 - Musical Experiences and Approaches, and Category 3 - Feelings and emotions evoked by music. The representation of these individuals is anchored in the experience they have with the CAPS, lived and socialized by common sense, through this particular social group workshop objectified in music therapy as a therapeutic modality enjoyable. The central core revealed the intrinsic relationship between users and the music, establishing a relationship of openness to use the same while its therapeutic use in workshops of substitute services for mental health. Peripherals elements issues are related to listen, share and experience music in the family. Intermediary Elements relate to the feelings and emotions evoked by music, given her close relationship with it. It was found in the study that music can be construed as an artifact of good therapeutic responsiveness to users, configuring it as an invigorating and enjoyable therapy, confirming the need for continuity of this activity, as well as its expansion into the service
Resumo:
It is a descriptive-exploratory research, with a quantitative approach, aiming to characterize typical occupational accident suffered by the professionals from nursery group, in the Intensive Care Units and Emergency in a hospital in Natal-RN, trying to identify the factors that contribute to those accidents; to identify some information taken by those professionals related to the accident risks; to know the procedures taken after each accident. This sample is composed by 176 professionals that are 44 nurses and 132 nursing technicians/auxiliaries, collected from March to April 2010. The results related to the personal characterization of the nursery group showed that 31 (18.61%) are between the 36-40 years of age; 148 (84.09%) females and 96 (55.68%) had finished High School. Related to the professional characterization, 53 (30.11%) are nurses, and 123 (69.88%) nursing technicians and auxiliaries; 44 (25.00%) are working as nurses, and 132 (75.00%) as nursing technicians and auxiliaries; 45 (25.56%) are working in the nursery area between 15 to 20 years and 11 months; 53 (30.11%) are in this institution between 10 to 14 years and 11 months; 79 (44.88%) work in the ICU; 55 (31.25%) are working in this area from 1 to 4 years and 11 months; 110 (62.50%) like to work in this area; 161 (91.47%) work 30 to 40 hours per week; 90 (51,13%) have another employment. Related to knowledge about typical occupational accident, 167 (94.88%) said they know about it; 96 (54.54%) know the accident rules; 103 (58.52%) think it is important to talk about this subject in the nursery courses; 92 (52.27%) said this subject is important to be discussed in the work and 372 (87.73%) think education is necessary to reduce accident. Related to the data about accidents, 104 (59.09%) have suffered typical occupational accident, among them 69 (39.20%) have suffered it once; 47 (36.19%) did not register any accident; 60 (57.69%) were caring some patient during the accident; 47 (45.19%) of them occurred in the ICU; 50 (48.07%) professionals were working during the night period; 69 (66.34%) have suffered perforation; 86 (82.69%) had upper limbs affected; 64 (61.53%) were affected by needle; about the reason of the accident, 89 (60.54%) said it occurred due to carelessness. Related to the accident evolution, 88 (85.57%) did not need to remain off work after accident; 13 (81.25%) remained off work during 15 days; 87 (83.65%) had no sequelae and for 101 (97.11%) it was not necessary rehabilitation. We conclude that typical occupational accident can occur with young workers who admit a knowledge about the subject, however they do almost nothing to prevent it. We believe this research has contributed to the characterization of this kind of accident suffered by the nursery group of a public hospital in Natal, and it can stimulate the creation and reformulation of personal protection against typical occupational accident suffered by nursery professionals
Resumo:
The study research case with a quantitative approach and prospective data, carried out between December 2010 and February 2011 with the aim of identifying the profile of women in the study, to characterize the acts of violence in the type, frequency, location occurrence and aggressor, analyze the steps taken after the occurrence of acts of violence and the main consequences on the victims. The population consisted of 285 workers in a tertiary institution in Rio Grande do Norte. The results showed that 99 (34.74%) have between 51 to 60 years of age, 78 (27.37%) of 41 to 50 and 62 (21.75%) between 20 and 30 years, are considered color white, 162 (56.84%) have completed higher education, 171 (60.00%) and of these 97 (56.73%) reported having some post-graduate degrees, are married, 141 (49.47%) and have from zero to one child, 148 (51.93%) reside in the south of the city of Natal, 146 (51.23%) have a monthly income of three to five minimum wages, 171 (60.00%) and are mostly in the Technical Administrative Sciences 152 (53.33%), 77 (27.02%) reported having experienced violence, 60 (62.50%) episodes of verbal aggression, 26 (27.08%) of bullying , 05 (5.21%) of physical abuse and 05 (5.21%) sexual harassment; 05 (100.00%) assaults were made by the spouse or partner of the victims and co-workers is another profession were responsible for 18 (30.00%) verbal aggression, 15 (57.69%) bullying and 03 (60.00%) sexual harassment, 02 (40.00%) of victims of physical aggression and 18 (30.00 %) of verbal abused only once, 10 (38.46%) of bullying and 02 (40.00%) of sexual harassment experienced four or more times 05 (100.00%) assaults occurred at domestic and work stood out with 36 (60.00%), verbal abuse, 22 (84.62%), moral harassment and 04 (80.00%) sexual harassment, 35 (36.46%) told colleagues work and 31 (32.29%) for family and friends in 75 (78.13%) cases there was no intervention, 07 (7.29) were unable to respond if something had been done and 14 (14.58% ) have been reported intervention of these, 09 (64.29%) were taken by the heads of the victims, 26 (32.10%) did not notify the fact on the ground that no action would be taken, 62 (80.52%) felt stress , 5 (1.76%) of women turned away from work after the episode of violence, accounting for 198 days of absenteeism. It is concluded that there is a high rate of violence against women, even when they have a good socioeconomic status, and in this sense is important to establish bases of new proposals for improving control of cases of health professionals, especially nurses, to approach patients with a more investigative, and that by identifying a case of violence, be instructed about the paths to be followed for notification while providing psychological support to victims.
Resumo:
The worker of the public service is loosing your acquisitive power by means of the politics of fiscal settlement. The ways out that were found in the health sector, especially in nursing, is being the increasing workday for beyond 40 or 20 hours established in the link of the work with the state. This survey has the object to identify the possible repercussion of the increasing workday in daily life workers from nursing in the public service of Rio Grande do Norte. The theory reference used was the work of Marx (1982) and Antunes (2000,2001) and the daily living in Heller (1991,1992). The methodology used was a qualitative survey in the exploration kind. The informations were gathered through interviews with open questions almost structured with workers of nursing, managers and representatives of entity. The analysis of informations were made through general categories, work, and daily life, using elements from dialetics-hermeneutics according to Minayo (1992,2002). In the analysis, it was identified that the ways that were found for the overcoming of the loss of acquisitive power were the many-employment; the extra scale of shift; the subletting of work posts and the substitution of friends in scales of work, and all of them being changed in increase. Other aspect realized was the move of rights, like vacation and medical license for the workers that act in extra scale. The tiredness, stress, and bad humor are influents factors in the development of work.. The reduction of free time makes in the workers ahguish because of the familiarity decreasement just as time to dedicate themselves to the technical-scientific improvement and for the cultivation of other aspects of subjectivity, as leisure, care and culture. The low salary and the non reajustment are the reasons for the adoption of part workers for the increasing workday, and government has been responsible for this situation. The conclusion was that the increasing workday has strong repercussions in the professional and personal daily life workers that made part of the survey
Resumo:
The competition in the telecommunications industry has grown in Brazil since the privatization, forcing companies that are active in the market to a growing commitment to quality products and services in order to survive. In this context, this work aims to understand the main factors that influence the degree of satisfaction exists in respect of a mobile operator with its corporate customers. The research covered theoretical concepts and analytical models of quality management system and models of indices related to the measurement of customer satisfaction. For the field research was carried out in a practical application of the main approaches based on this thesis by a case study in corporate segment, through a questionnaire applied to 10 consultants and 40 corporate customers of that company. Comparing the results of research with the consultants and corporate clients there is the concern of respondents to the indicators that comprise the constructs of customer satisfaction, commitment calculated, the price index and the handling of complaints, denoting the dissatisfaction of the general assessment for corporate customers with the carrier, against its current expectations. It is concluded that the mobile operator of the telecommunications industry have a big challenge, after ten years of privatization and consequently the period of rapid expansion of customer base and with the depleted, retain corporate customers as highly strategic, thus avoiding that migrate to other companies. We emphasize the need for further research and analysis of different approaches through research and using the same models to specifically evaluate and measure customer satisfaction of mobile enterprise, to adjust the model to the national market. Finally, we suggest the creation of an effective customer loyalty program with a strategy of relationship and specific to the corporate sector of mobile telephony
Resumo:
In the last decades there was a significant increasing of the numbers of researchers that joint efforts to find alternatives to improve the development of low environmental impact technology. Materials based on renewable resources have enormous potentials of applications and are seen as alternatives for the sustainable development. Within other parameters, the sustainability depends on the energetic efficiency, which depends on the thermal insulation. Alternative materials, including vegetal fibers, can be applied to thermal insulation, where its first goal is to minimize the loss of energy. In the present research, it was experimentally analyzed the thermal behavior of fiber blankets of sisal (Agave sisalana) with and without surface treatment with oxide hidroxide (NaOH). Blankets with two densities (1100/1200 and 1300/1400 g/m2) were submitted to three rates of heat transfer (22.5 W, 40 W and 62.5 W). The analysis of the results allowed comparing the blankets treated and untreated in each situation. Others experiments were carried out to obtain the thermal conductivity (k), heat capacity (C) and the thermal diffusivity (α) of the blankets. Thermo gravimetric analyses were made to the verification of the thermal stability. Based on the results it was possible to relate qualitatively the effect of the heat transfer through the sisal blankets subjected to three heat transfer rates, corresponding to three temperature values (77 °C, 112 °C e 155 °C). To the first and second values of temperature it was verified a considerable reduction on the rate of heat transfer; nevertheless, to the third value of temperature, the surface of the blankets (treated and untreated) in contact with the heated surface of the tube were carbonized. It was also verified, through the analyses of the results of the measurements of k, C e α, that the blankets treated and untreated have values near to the conventional isolating materials, as glass wool and rock wool. It could be concluded that is technically possible the use of sisal blankets as constitutive material of thermal isolation systems in applications where the temperature do not reach values greater than 112 ºC
Resumo:
Porous ceramics have many applications: thermal insulation, catalytic support, materials to fire protection, filters, and others. There are many techniques to production of ceramic filters. One technique to obtain ceramic filters is the replication method. This method consists in the impregnation of polymeric foam with ceramic slurry followed by a heating treatment that will burn out the organic elements and sintering of the material, resulting of a replication of the original foam. To perform their functions ceramic filters must satisfy mechanical requirements and permeability parameters (darcian k1 and no-darcian k2). The permeability and the strength of the ceramic material are dependent of the pore size and pore distribution. To the use at high temperatures the evaluation of mechanical properties in these temperatures is necessary. In this work the mechanical behavior of two commercial porous ceramics (10 and 40 poros per inch) was studied these materials were submitted to compression and four-point flexure test (room temperature, at 1000 °C, after thermal shock). Density and porosity measurements, permeability tests and microstructural analysis by scanning electronic microscopy (SEM) were realized. The Results showed that the decrease of mechanical strength of these materials, when submitted to thermal shock, occur for propagation of new cracks from cracks pre-existing and the permeability depends of the pore size
Resumo:
The need for new sources of energy and the concern about the environment have pushed the search for renewable energy sources such as ethanol. The use of lignocellulosic biomass as substrate appears as an important alternative because of the abundance of this raw material and for it does not compete with food production. However, the process still meets difficulties of implementation, including the cost for production of enzymes that degrade cellulose to fermentable sugars. The aim of this study was to evaluate the behavior of the species of cactus pear Opuntia ficus indica and Nopalea cochenillifera, commonly found in northeastern Brazil, as raw materials for the production of: 1) cellulosic ethanol by simultaneous saccharification and fermentation (SSF) process, using two different strains of Saccharomyces cerevisiae (PE-2 and LNF CA-11), and 2) cellulolytic enzymes by semi-solid state fermentation (SSSF) using the filamentous fungus Penicillium chrysogenum. Before alcoholic fermentation process, the material was conditioned and pretreated by three different strategies: alkaline hydrogen peroxide, alkaline using NaOH and acid using H2SO4 followed by alkaline delignification with NaOH. Analysis of composition, crystallinity and enzymatic digestibility were carried out with the material before and after pretreatment. In addition, scanning electron microscopy images were used to compare qualitatively the material and observe the effects of pretreatments. An experimental design 2² with triplicate at the central point was used to evaluate the influence of temperature (30, 40 and 45 °C) and the initial charge of substrate (3, 4 and 5% cellulose) in the SSF process using the material obtained through the best condition and testing both strains of S. cerevisiae, one of them flocculent (LNF CA-11). For cellulase production, the filamentous fungus P. chrysogenum was tested with N. cochenillifera in the raw condition (without pretreatment) and pretrated hydrothermically, varying the pH of the fermentative medium (3, 5 and 7). The characterization of cactus pear resulted in 31.55% cellulose, 17.12% hemicellulose and 10.25% lignin for N. cochenillifera and 34.86% cellulose, 19.97% hemicellulose and 15.72% lignin for O. ficus indica. It has also been determined, to N. cochenillifera and O. ficus indica, the content of pectin (5.44% and 5.55% of calcium pectate, respectively), extractives (26.90% and 9.69%, respectively) and ashes (5.40% and 5.95%). Pretreatment using alkaline hydrogen peroxide resulted in the best cellulose recovery results (86.16% for N. cochenillifera and 93.59% for O. ficus indica) and delignification (48.79% and 23.84% for N. cochenillifera and O. ficus indica, respectively). This pretreatment was also the only one which did not increase the crystallinity index of the samples, in the case of O. ficus indica. However, when analyzing the enzymatic digestibility of cellulose, alkali pretreatment was the one which showed the best yields and therefore it was chosen for the tests in SSF. The experiments showed higher yield of conversion of cellulose to ethanol by PE-2 strain using the pretreated N. cochenillifera (93.81%) at 40 °C using 4% initial charge of cellulose. N. cochenillifera gave better yields than O. ficus indica and PE-2 strain showed better performance than CA-11. N. cochenillifera proved to be a substrate that can be used in the SSSF for enzymes production, reaching values of 1.00 U/g of CMCase and 0.85 FPU/g. The pretreatment was not effective to increase the enzymatic activity values