Metalização mecânica de ZrO2 com Ti para brasagem ZrO2/Aço com ligas de adição sem metal ativo

Metal/ceramic interfaces using zirconia have dominated the industrial applications in the last decade, due to the high mechanical strength and fracture toughness of zirconia, especially at temperatures below 300 ºC. Also noteworthy is the good ionic conductivity in high temperatures of this component. In this work joining between ZrO2 Y-TZP and ZrO2 Mg-PSZ with austenitic stainless steel was studied. These joints were brazed at high-vacuum after mechanical metallization with Ti using filler alloys composed by Ag-Cu and Ag-Cu-Ni. The influence of the metallization, and the affinity between the different groups (ceramic / filler alloys) was evaluated, in order to achieve strong metal/ceramic joints. Evaluation of joints and interfaces, also the characterization of base materials was implemented using various techniques, such as: x-ray diffraction, leak test, three-point flexural test and scanning electron microscopy with chemical analysis. The microstructural analysis revealed physical and chemical bonds in the metal/ceramic interfaces, providing superior leak proof joints and stress cracking, in order to a good joint in all brazed samples. Precipitation zones and reaction layers with eutetic characteristics were observed between the steel and the filler metal

Mecanismos de desgaste, história térmica e ciclo de vida de componentes de um motor de combustão interna de aeromodelo

We developed an assay methodology that considered the temperature variation and the scanning electron microscopy as a method to quantify and characterize respectively the consumption evolution in three 46 LA machines, with internal combustion and two-stroke engines, 7.64 cm3 cylinder capacity, 23.0 millimeters diameter and 18.4 millimeters course, RPM service from 2.000 to 16.000 rpm, 1.2 HP power, and 272 grams weight. The investigated engines components were: (1) head of the engine (Al-Si alloy), (2) piston (Al-Si alloy) and (3) piston pin (AISI 52100 steel). The assays were carried out on a desktop; engines 1 and 2 were assayed with no load, whereas in two assays of engine 3 we added a fan with wind speed that varied from 8.10 m/s to 11.92 m/s, in order to identify and compare the engine dynamic behavior as related to the engines assayed with no load. The temperatures of the engine s surface and surroundings were measured by two type K thermopairs connected to the assay device and registered in a microcomputer with data recording and parameters control and monitoring software, throughout the assays. The consumed surface of the components was analyzed by scanning electron microscopy (SEM) and microanalysis-EDS. The study was complemented with shape deformation and mass measurement assays. The temperature variation was associated with the oxides morphology and the consumption mechanisms were discussed based on the relation between the thermal mechanical effects and the responses of the materials characterization

Desidratação de polpas de frutas pelo método foam-mat

This study aimed to investigate the foam mat drying process of pineapple and mango pulp, as well as to evaluate the final product quality. Initially, the selection of fruit and additives was conducted based on density and stability determinations of mango, seriguela, umbu and pineapple foams. After selecting pineapple and mango for further studies, the fruit pulps and fruit foams were characterized in regard to their physicochemical composition. The temperature (60oC or 70oC) and the foam thickness (4 and 11 mm) were evaluated in accordance to the obtained drying curves and after model adjustment. Mango and pineapple powders obtained at the best process conditions were characterized in regard to their physicochemical composition, solubility, reconstitution time. Yoghurts were prepared with the addition of pineapple and mango powders and they were evaluated for their sensory acceptance. Results show that the best drying rates were achieved by using 70o C and layers 4mm thick for both fruits. The Page model successfully fitted the drying experimental data and it can be used as a predictive model. Pineapple and mango powders showed acid pH, high soluble solids content, low water activity (approx. 0.25), lipids between 1.46% and 2.03%, protein around 2.00%, and ascorbic acid content of 17,73 mg/100g and 14.32 mg/100g, for mango and pineapple, respectively. It was observed higher ascorbic acid retention for pineapple and mango powders processed at 70o C, which would be explained by the lower drying time applied. The fruit powders exhibited high solubility and fast reconstitution in water. The sensory acceptance indexes for yoghurts with the addition of both fruit powders were higher than 70%, which reflect the satisfactory product acceptance

Propriedades magnéticas quase-estáticas de filmes ferromagnéticos amorfos de FeCuNbSiB

Today, one of the topics that attracts interest of the scientific community is the understanding of magnetic properties of magnetic systems with reduced dimensions, in particular, ferromagnetic thin films. In this case, the comprehension and control of these properties, as well as the development of routes to obtain them, are crucial issues in many aspects of current and future technologies for storage and transmission of information in the electro-electronic industry. There are several materials that exhibit soft magnetic properties, and we highlight the amorphous alloys and that ones obtained by partial crystallization, so-called nanocrystalline materials. The production of these alloys as magnetic ribbons is very common in scientific and technological area, but there are just a few works related to the production of these alloys as thin films. In this work, we studied the quasi-static magnetic properties of ferromagnetic thin films based on FeCuNbSiB in a wide range of thicknesses, from 20 to 500 nm, produced by sputtering. In particular, after the structural characterization performed via X-ray diffraction, the magnetic properties of the sets of samples were investigated using experimental magnetization curve, obtained using a vibrating sample magnetometer, as well as through theoretical curves obtained by theoretical modeling and numerical computation. The modeling process is based on the Stoner Wohlfarth model applied to three dimensions, and adds some energy terms, using as reference experimental results of magnetization. In this case, from the comparison between theoretical and experimental results and the analysis of the constant anisotropy behavior as a function of film thickness, we aim to obtain further information on the magnetization process of the samples, to identify routes for the production of thin films and develop a theoretical to films to use it, in the future, in the obtainment of the theoretical curves of some magnetic measurements, such as magnetoimpedance and magnetoresistance

O acolhimento como promoção da saúde entre pacientes com câncer

Cancer has been affecting people all around the world; disregard sex, ethnicity or social class. Despite the fact it is not always deadly, to be diagnosed and treated of cancer brings a lot of physical, emotional and social suffering, specially for those with less economic resources. Considering the complexity of the problem, there has been perceived that medical treatment is not enough to support cancer patients. There is an increasing understanding about their necessity of integral care, supposed to be given by a multidisciplinary health care equip that can consider all the different aspects involved in the illness process. Everyone has a particular way of been ill or healthy, and gives different meanings to the experienced events. The starting point of the research was the contact with a called work `group of shelter', developed with cancer patients by a multidisciplinary health care equip working on the LIGA Norte Riograndense Contra o Câncer. The research goal is to identify meanings people give to the shelter they receive in the group and to understand the way they experience the disease. Considering it singularity of this process, one worked with individually half-structuralized interviews, carried through with nine patients of the chemotherapy clinics and suck, that they had passed for the experience of the group of shelter, having approached getting ill, the treatment, the shelter and the recreation of the psychosocial processes (or not) after all this process. It was chosen as focus of analysis the creation of psychosocial processes and production of felt of these social actors through its discourse analysis perspective, boarded in accordance with the following thematic axles: the experience of the cancer, the shelter and recreation of the psychosocial processes the life. It was found that shelter has an extensive meaning going beyond the the group and involving others besides the multidisciplinary health care equip, and being important to give each patient the best possible benefit. It was also identified the importance of other social actors, such as relatives, friends and neighbors; added of religious faith, mentioned by all interviewees. It is to be considered the recovering capacity shown by eight interviewees, demonstrated by changing the way of interacting with others, getting new values and behaviors, and demonstrating more wisdom. We can consider the possibility of making this strategy to become part of the everyday practices of others health services working with cancer patients, what we think can help to minimize their suffering

Estudo das ligas titânio-zircônio resultantes do processo de fundição plasma-skull para aplicações como biomateriais

The aim of this work was to study a series of 11 different compositions of Ti-Zr binary alloys resistance to aggressive environment, i. e., their ability to keep their surface properties and mass when exposed to them as a way to evaluate their performance as biomaterials. The first stage was devoted to the fabrication of tablets from these alloys by Plasma-Skull casting method using a Discovery Plasma machine from EDG Equipamentos, Brazil. In a second stage, the chemical composition of each produced tablet was verified. In a third stage, the specimen were submitted to: as-cast microstructure analysis via optical and scanning electron microscopy (OM and SEM), x-ray dispersive system (EDS) chemical analysis via SEM, Vickers hardness tests for mechanical evaluation and corrosion resistence tests in a 0.9% NaCl solution to simulate exposition to human saliva monitored by open circuit potential and polarization curves. From the obtained results, it was possible to infer that specimens A1 (94,07 wt% Ti and 5,93% wt% Zr), A4 (77,81 wt % Ti and 22,19 wt % Zr) and A8 (27,83 wt% Ti and 72,17 wt% Zr), presented best performance regarding to corrosion resistance, homogeneity and hardness which are necessary issues for biomaterials to be applied as orthopedic and odontological prosthesis

Processo de cuidar de um centro de tratamento oncológico

The objective was to understand the process of caring for a center for cancer treatment from the perspective of nurses and patients. This is a qualitative research, xploratory and descriptive, performed in a cancer treatment center in Natal / RN / Brazil. Data collection occurred between August 2013 and February 2014, being effected by means of two techniques: photographic record and projective interviews with nurses and patients. Social actors included in the study were ten professional nursing and ten patients admitted to the surgical department of the institution. The criteria used for inclusion of professionals were: be professional in the field of nursing, being an employee of the hospital, to be inserted in the scale of nurses of the institution at the time of data collection. For the patients were included who had preserved their cognitive abilities and who were hospitalized and at any stage of treatment. We used content analysis proposed by Bardin, for the analysis of material collected during projective interview. The research followed the ethical and legal principles that govern scientific research on human beings, being conducted by the project approval by the Research Ethics Committee of the Northern League Against Cancer Riograndense with 295 673 and look CAAE 16104313.0.0000.5293. Referring to nurses, they demonstrated different views about care, which sprouted from a holistic, multidisciplinary approach and welcoming, as well as linked to the performance of procedures and compliance with the requirements technicality. Furthermore, these subjects also showed that care unfolds through the actions of management in carrying out the records in the humanization of care by meeting the needs of the patient and ambience. Front of patients, it is noteworthy that, for them, care happens through attitudes of caring and professional approach, and by performing procedures, being mentioned as a careless lack of structure of the institution and the discomfort caused by this condition factors. It was evident also that the actors involved in the care, the perception of professionals and patients, are represented by nurses, doctors, psychologists, nutritionists, as well as kitchen assistants and cleaners; beyond family companion, the individual himself as responsible for their care and volunteer caregiver. In this opportunity, it is concluded 9 that an understanding of care from the perspective of nurses and patients involves broad issues ranging from perceptions of care that embraces a dynamic complex elements and attitudes imbued with meanings, in which those involved can assume both the role of carers as care beings, even a carefully tied to prescribed routines and performing procedures. Thus, the findings described refer to reflections on the care provided to cancer patients and whether this, in fact, translates principles of a humane practice

Processo de cuidar de crianças hospitalizadas com câncer

The objective was to understand the process of care in the perception of hospitalized children with cancer. This is a descriptive study of qualitative approach. Data were collected between the months of October 2013 and January 2014, through photographic records and semi-structured interview consisting of questions relating to the identification of age, sex, diagnosis and length of stay and a script of questions related to the recorded pictures. Eight children were included aged between six and twelve who were admitted to a pediatric oncology sector, located in the city of Natal / RN. The criteria used in the sample were: being hospitalized for cancer treatment; and present favorable physical conditions for carrying out the data collection. For the treatment of collected material was used content analysis, thematic modality. The study followed the ethical and legal principles governing scientific research with human beings and took place with the approval of the project by the Ethics and Research Committee of the Northern League Riograndense against Cancer, with opinion registered under number 329 015 and CAAE 16097613.9.0000.5293. According to the results it was found that, for the child, the care happens through technical activities, such as making procedures and the use of personal protective equipment, as well as through the dialogic relationship, which favors the establishment of confidence in care professional. Caring also means developing activities that promote well-being, the fun and the social and cognitive development, highlighting thus the playful, during hospitalization, as an auxiliary tool in the care process. During hospitalization, the child identifies two individuals responsible for their care, accompanying family and professional, and nursing professionals the most cited in moments of care. , Also of note, the promotion of care, in the perception of the child related to the infrastructure of the institution, environmental cleaning, personal hygiene, the medicalization and the food. It is concluded that care understood by the child, whilst still maintaining relations with the biomedical model, points to a new perspective that should consider the biological, social and psychological of acquiring cancer without unlink them of the development child. 9 Moreover, we see the child as an active social actor in this process, and therefore needs to be heard and answered their needs

Análise experimental de danos em pistões de motor à gasolina operando com adição de gás hidróxi

The addition of hydrogen gas as an alternative fuel source has been widely used, as well reported in scientific literature. Today, several experiments are underway for the use of hydrogen generators (electrolysers) demand for motor vehicles. In all these products their ads manufacturers claim that this provides a reduction of fuel consumption, reduces the emission levels of toxic gas by the discharge and improves engine life. This research analyzes the physical structure of engine components using electrolysis on demand. To this end, a stationary system was fitted with a power generator of electricity, drum roller and adapted two electrolyzers: a dry cell and wet cell other. In steps observation were consumption analyzes in four work load ranges and observing the piston engine, which has been cut and analyzed by Optical Microscopy (OM), Scanning Electron Microscopy and Dispersive Energy (SEM-EDS), X – Ray Diffraction (XRD) and Confocal Microscopy, the stationary system in each step. The results showed a considerable reduction in fuel consumption and a high corrosion in the original factory piston constituted of aluminum-silicon alloy. As corrosion barrier was made a plasma nitriding in the piston head, which proved resistant to attack by hydrogen, although it has presented evidence also, of having been attacked. It is concluded that the automotive electrolysers can be a good choice in terms of consumption and reducing toxic gas emissions, but the material of the combustion chambers of vehicles must be prepared for this purpose.

Estudo da correlação das características clínico-patológicas do câncer colorretal com a expressão imunohistoquímica de proteínas da progressão tumoral

Except the non-melanoma skin tumors, colorectal cancer is the second most common in the Southeastern Region of Brazil, the third most common in the Southern and Central Regions. It is also the forth most common in the Northern Region and it is the fifth one in the Northeastern. To assess pathological and clinical variables of colorectal Cancer is crucial to know the possible conclusions for the survival of patients and point out the characteristics in the progress of tumor, such as the profile of tumor invasion and its angiogenesis. This work focuses on analyzing clinically and pathologically some settings in colorectal cancer patients (CRC) in the city of Natal and its countryside through those variables as parameters of prognosis and determine the level of protein expression, for instance: E-cadherin (E-cad), beta- -catenin (β-cat), galectin-3 (gal-3), matrix metalloproteinases (MMP) 2 and 9 and vascular-endothelial growth factor alpha (α VEGF) in the tumor tissues. A retrospective study was done in colorectal cancer cases in the regions of Rio Grande do Norte state from 1995 to 2005, specifically in Natal city/RN/Brazil. The pathological and clinical variables, such as: age, gender, ethnicity, lifestyle, family history, the location of the primary tumor, level of differentiation, TDM staging, modified Dukes’, treatment and survival were analyzed. The pathological and clinical data were collected from medical records through a specific form and were filed on Excel. A total of 534 patients were selected from the Pathology Department file in this institution, however, 176 patients were excluded. 358 patients were included for Epidemiological analysis and its clinical and pathological correlations were selected. 180 patients were also selected for histological and immunohistochemical studies. The tumor progression of these selected proteins mentioned before were analyzed. The Paraffin blocks of these samples were treated by Microarray Tissue technique and its blades subjected to immunohistochemistry to test the intensity of these proteins in tumor tissues. The results of this analysis were correlated with clinicopathologic variables of patients. Statistical analysis using the chi-frame Pearson test and analysis of midlife by Kaplan-Meier curve was also utilized. P values < 0.05 were considered statistically significant. The average age of our sample was 58.8 years and 51.7 % were female. Alcohol consumption has increased by 1.71 time the risk of death by CCR (p = 0.034) and tobacco consumption increased 2.7 times the chance of developing tumors of high TNM stage (p = 0.001). Cancer patients had a family history of 3,833 times the chance of developing the CCR (p = 0.002). The expression of MMP-2 showed a significant association with tumors of high TNM stage (p <0.046) and mortality (p = 0.041). The α VEGF expression had statistically significant correlation with high TNM stage (p <0.009), degree of cell indifferentiation (p <0.025) and mortality (p <0.035). Expressions of E-cadherin and beta-catetina demonstrated tumor linked to high TNM stage (p = 0.0001) and Dukes› modified (p = 0.05), lesions in the rectum (p = 0.03 and p = 0.007, respectively), smoking (p = 0.05) and indifferentiation (p = 0.001). The expression of Gal-3 showed statistical significance with high TNM stage of patients (p = 0.01), smokers (p = 0.01), alcohol drinking (p = 0.03), indifferentiation (p = 0.0001) and mortality (p = 0.0001). Based on the results, therefore, we could realize that lifestyle and family history had correlation in the CCR prognosis, as well as MMP-2 expression, MMP-9, VEGF alpha, E-cadherin, Beta-catenin and Galectin-3 were important prognostic markers in tumor progression in colorectal cancer.

Evaluation of the castability of a Co-Cr-Mo-W alloy varying the investing technique

O objetivo deste estudo foi comparar a fusibilidade de ligas de Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) e Co-Cr-Mo (Vera-PDI), incluídas em revestimentos à base de fosfato, sílica ou utilizando uma técnica mista. Uma rede de nylon quadrada (10 X 10 mm) com 100 espaços abertos serviu de modelo para construção de padrões de cera, que foram incluídos com revestimento à base de sílica, revestimento fosfatado e técnica mista (camada de revestimento fosfatado com 2 mm de espessura + revestimento à base de sílica). Quarenta e cinco espécimes (5 para cada condição experimental) foram fundidos sob chama de gás-oxigênio e a seguir jateados com óxido de alumínio. O número de segmentos fundidos completos foi contado para obter uma percentagem designada como "valor de fusibilidade", representando a precisão da liga em reproduzir os detalhes do molde. A análise estatística por meio de ANOVA a dois critérios e teste Tukey mostrou que, comparando-se as ligas, a Remanium 2000 teve fusibilidade estaticamente semelhante (p>0,05) à da Vera PDI e inferior à da liga Durabond (p<0,05). Considerando os resultados da técnica mista, a liga Remanium 2000 teve menor valor de fusibilidade (p<0,05) que as ligas Durabond e Vera PDI, que apresentaram valores estatisticamente semelhantes entre si (p>0,05). Concluindo, a fusibilidade da liga de Co-Cr-Mo-W (Remanium 2000) foi comparável à da liga de Co-Cr (Vera PDI) e inferior à da liga de Ni-Cr alloy (Durabond). À exceção da liga Remanium 2000, a técnica de inclusão mista aumentou consideravelmente a capacidade das ligas testadas de reproduzir os detalhes do molde, quando comparada à técnica de inclusão em revestimento fosfatado. A técnica de inclusão mista representa uma alternativa para melhorar a fusibilidade de ligas de metais básicos sem afetar a qualidade superficial das peças metálicas.

Evaluation of the castability of a Co-Cr-Mo-W alloy varying the investing technique

O objetivo deste estudo foi comparar a fusibilidade de ligas de Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) e Co-Cr-Mo (Vera-PDI), incluídas em revestimentos à base de fosfato, sílica ou utilizando uma técnica mista. Uma rede de nylon quadrada (10 X 10 mm) com 100 espaços abertos serviu de modelo para construção de padrões de cera, que foram incluídos com revestimento à base de sílica, revestimento fosfatado e técnica mista (camada de revestimento fosfatado com 2 mm de espessura + revestimento à base de sílica). Quarenta e cinco espécimes (5 para cada condição experimental) foram fundidos sob chama de gás-oxigênio e a seguir jateados com óxido de alumínio. O número de segmentos fundidos completos foi contado para obter uma percentagem designada como "valor de fusibilidade", representando a precisão da liga em reproduzir os detalhes do molde. A análise estatística por meio de ANOVA a dois critérios e teste Tukey mostrou que, comparando-se as ligas, a Remanium 2000 teve fusibilidade estaticamente semelhante (p>0,05) à da Vera PDI e inferior à da liga Durabond (p<0,05). Considerando os resultados da técnica mista, a liga Remanium 2000 teve menor valor de fusibilidade (p<0,05) que as ligas Durabond e Vera PDI, que apresentaram valores estatisticamente semelhantes entre si (p>0,05). Concluindo, a fusibilidade da liga de Co-Cr-Mo-W (Remanium 2000) foi comparável à da liga de Co-Cr (Vera PDI) e inferior à da liga de Ni-Cr alloy (Durabond). À exceção da liga Remanium 2000, a técnica de inclusão mista aumentou consideravelmente a capacidade das ligas testadas de reproduzir os detalhes do molde, quando comparada à técnica de inclusão em revestimento fosfatado. A técnica de inclusão mista representa uma alternativa para melhorar a fusibilidade de ligas de metais básicos sem afetar a qualidade superficial das peças metálicas.

Controle ativo de vibração em estruturas inteligentes utilizando um controlador por modos deslizantes com compensação difusa

Smart structures and systems have the main purpose to mimic living organisms, which are essentially characterized by an autoregulatory behavior. Therefore, this kind of structure has adaptive characteristics with stimulus-response mechanisms. The term adaptive structure has been used to identify structural systems that are capable of changing their geometry or physical properties with the purpose of performing a specific task. In this work, a sliding mode controller with fuzzy inference is applied for active vibration control in an SMA two-bar truss. In order to obtain a simpler controller, a polynomial model is used in the control law, while a more sophisticated version, which presents close agreement with experimental data, is applied to describe the SMA behavior of the structural elements. This system has a rich dynamic response and can easily reach a chaotic behavior even at moderate loads and frequencies. Therefore, this approach has the advantage of not only obtaining a simpler control law, but also allows its robustness be evidenced. Numerical simulations are carried out in order to demonstrate the control system performance.

Controle ativo de vibração em estruturas inteligentes utilizando um controlador por modos deslizantes com compensação difusa

Smart structures and systems have the main purpose to mimic living organisms, which are essentially characterized by an autoregulatory behavior. Therefore, this kind of structure has adaptive characteristics with stimulus-response mechanisms. The term adaptive structure has been used to identify structural systems that are capable of changing their geometry or physical properties with the purpose of performing a specific task. In this work, a sliding mode controller with fuzzy inference is applied for active vibration control in an SMA two-bar truss. In order to obtain a simpler controller, a polynomial model is used in the control law, while a more sophisticated version, which presents close agreement with experimental data, is applied to describe the SMA behavior of the structural elements. This system has a rich dynamic response and can easily reach a chaotic behavior even at moderate loads and frequencies. Therefore, this approach has the advantage of not only obtaining a simpler control law, but also allows its robustness be evidenced. Numerical simulations are carried out in order to demonstrate the control system performance.

O algodão sem veneno do Assentamento Queimadas, na Paraíba: agentes sociais, alinhamento em rede, produção e comercialização

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior