14 research outputs found
Minimizing the Adhesion Effects in Food Packages Forming by the Use of Advanced Coatings
The metal packaging industry used for food application has undergone drastic changes in the demands of its final consumers. The raw material for these packages, is a low carbon steel coated with a thin layer of tin (2,0 g/m2), also known as tinplate. The stamping process of these packages occurs at room temperature and is critically influenced by the tin transfer from the steel surface to the tool surface, mainly due to the tin softness. This problem is easily solved using lubrification but the purpose of this study will be the reduction or even absence of lubricants during the process in order to comply with costumers’ requirements. A successful way to minimize the consumption of lubricants is to use tools which are coated with PVD (Physical Vapour Deposition) advanced coatings deposited with unbalanced magnetron sputtering technique. Thin WC (Tungsten Carbide) and CrCN (Chromium Carbonitride) coatings were deposited using PVD on tool stamping steel – AISI D2. Block on ring tribological tests were performed on the coatings against tinplate counterface in order to investigate their wear performance, with particular emphasis on the material transfer (tin) phenomena during the sliding tests. The results allowed for selecting the best coating tested with a view to avoid the tin adhesion to the die.info:eu-repo/semantics/publishedVersio
Electrochemical behavior of Ti/Al2O3 interfaces produced by diffusion bonding
In the field of biomedical applications a special interest exists regarding the study of the physicochemical and mechanical behaviour of materials, with special focus on the electrochemical degradation of metal/ceramic interfaces. In fact, etal/ceramic interfaces may be present in several
biomedical devices, ranging from external or implantable sensors, to dental implants. Diffusion
bonding represents an important technique since, in opposition to other production technologies,
such as active metal brazing, avoid the possible liberation of certain chemical components
harmful to health. The aim of this work is to study the electrochemical degradation of the interface
formed between commercially pure Ti and Al2O3 produced by diffusion bonding, in contact with
a physiological solution. The present approach included the evaluation of the contribution of individual
and pairs of interfacial layers on the global degradation processes. For this propose d.c.
electrochemical techniques were used to monitor the open-circuit potential, and to perform
potentiodynamic polarization and galvanic corrosion evaluation. Also, electrochemical impedance
spectroscopy was used as a complementary technique of the corrosion behaviour of the
interface. Chemical composition and morphology of samples and corrosion products were evaluated
by SEM and EDS analysis. According to experimental results, two principal reaction layers
were formed in the interface: TiAl and Ti3Al. The TiAl layer appears to be the responsible for the
strong increase in corrosion rate of the interface.Fundação para a Ciência e Tecnologia -POCTI/CTM/33384/2000; SFRH/BPD/
5518/2001
Avaliação energética da produção de etanol utilizando como matéria-prima a cana-de-açúcar
Análise energética do novo sistema de produção de maracujá amarelo na região de MarÃlia-SP
Effects of cholinergic stimulation with pyridostigmine bromide on chronic chagasic cardiomyopathic mice
The aim of the present study was to assess the effects of an anticholinesterase agent, pyridostigmine bromide (Pyrido), on experimental chronic Chagas heart disease in mice. To this end, male C57BL/6J mice noninfected (control:Con) or chronically infected (5 months) with Trypanosoma cruzi (chagasic:Chg) were treated or not (NT) with Pyrido for one month. At the end of this period, electrocardiogram (ECG); cardiac autonomic function; heart histopathology; serum cytokines; and the presence of blood and tissue parasites by means of immunohistochemistry and PCR were assessed. In NT-Chg mice, significant changes in the electrocardiographic, autonomic, and cardiac histopathological profiles were observed confirming a chronic inflammatory response. Treatment with Pyrido in Chagasic mice caused a significant reduction of myocardial inflammatory infiltration, fibrosis, and hypertrophy, which was accompanied by a decrease in serum levels of IFN\u3b3 with no change in IL-10 levels, suggesting a shift of immune response toward an anti-inflammatory profile. Lower nondifferent numbers of parasite DNA copies were observed in both treated and nontreated chagasic mice. In conclusion, our findings confirm the marked neuroimmunomodulatory role played by the parasympathetic autonomic nervous system in the evolution of the inflammatory-immune response to T. cruzi during experimental chronic Chagas heart disease in mice