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Al-Rubaie K.S.,Centro Universitario Tupy | Pohl M.,Ruhr University Bochum
Wear | Year: 2014

The two-body abrasion behaviour of three Ni-Hard 4 alloys after destabilisation and subcritical heat treatments was studied. The destabilisation treatment was carried out at 820. °C for 4. h followed by air cooling to room temperature. The subcritical treatment was carried out at three temperatures of 300, 450, and 550. °C for 4. h and then air cooling to room temperature. Using a pin abrasion test, the alloys were abraded on three types of bonded abrasives (silicon carbide, corundum, and flint). The results showed that the abrasive used had an essential effect on the wear resistance of the alloys. The as-hardened microstructure containing a retained austenite of 27% exhibited the greatest abrasion resistance, whereas the as-tempered at 550. °C gave the worst. Very poor correlations were found between the abrasion resistance and bulk hardness of test alloys. Therefore, a general model "equivalent hardness" was developed to explain the abrasion behaviour. In this model, the influence of matrix work hardening due to abrasion was highlighted. The equivalent hardness equals the sum of the products of the volume fraction of each phase (matrix and carbide) and its microhardness; the hardness of the abraded matrix was considered. Strong correlations were found between the abrasion resistance and equivalent hardness of test alloys. © 2014 Elsevier B.V. Source


Kleinschmidt A.C.,Centro Universitario Tupy | Balzer P.S.,Centro Universitario Tupy
Revista Materia | Year: 2014

The interest in natural fiber composites with thermoplastic polymers is growing every year. Natural fibers have advantages such as low density, low abrasion, low cost, are biodegradable and self-sustainable, since they are natural and renewable source. Among the thermoplastic resins viable for employment fiber banana stands out poly (vinyl chloride) - PVC for its versatility compared to its formulation, because there is the need to incorporate additives during processing, making adaptable to multiple applications. The objective of this work was to study the influence of type of banana fibers (FB) treatment in the properties of rigid poly (vinyl chloride) (PVC). Mechanical properties, thermal stability and water absorption of composite PVC/FB were evalueted for the effect of alkaline treatments, with maleic anhydride and acetylation of banana fibers. The composites were obtained in two-roll open mixer followed by injection of test samples. The results indicate that treatment with maleic anhydride and acetylation exhibit better impact resistance and lower water absorption than the alkaline treatment. The thermal properties did not change significantly with the addition of banana fibers treated and untreated. © 2014, Universidade Federal do Rio de Janeiro. All rights reserved. Source


Galhart D.L.,Centro Universitario Tupy | Batiz E.C.,Centro Universitario Tupy | Santos A.J.,Centro Universitario Tupy
Espacios | Year: 2014

Companies need to compete both in domestic and international markets is therefore of paramount importance tied high productivity at a lower cost. For this one needs ergonomic environments, appropriate working hours, work pace appropriate to the capabilities of workers, among other factors. The absence of these factors contribute negatively in effectively carrying out production plans. In industries that produce ham, includes among its activities the demoulding process which involves, among others, two critical ergonomic problems: too much physical exertion and repetitive activities since this activity is done manually. The objective of this paper is to propose a device to unmold ham. From the introduction of this technology will be able to minimize the damage caused by the manual production and promote improvements in physical integrity, safety, comfort and health of workers. To accomplish our objective we conducted a field study at a large food company, with the purpose of collecting key indicators of productivity and ergonomic indicators involved in demoulding ham. With defined indicators was prepared the design of the equipment following a systematic development of product design. Later a prototype was developed and tested in the company, this company object of study, obtaining as a result the gain ergonomic for workers and financial gain for the company. Source


Miranda K.W.,Centro Universitario Tupy | Miranda K.W.,Santa Catarina State University | De Souza E.C.,Centro Universitario Tupy | Tomaz M.,Santa Catarina State University | And 2 more authors.
Materials Research | Year: 2015

This study aims the synthesis of copolymers of poly (l-lactic acid) and polycaprolactone by ring opening polymerization. The reactions between l-lactide (LLA) and ε-caprolactone (CL) monomers, in 100/0, 95/5, 90/10 and 80/20 LLA/CL mass ratios, were conducted in refluxing toluene, using Stannous octoate as iniciator, methanol as co-iniciator and inert atmosphere (N2). The reaction medium was maintained under stirring at 120 °C for 24 hours. The samples were characterized by carbon-13 and proton nuclear magnetic resonance (C13-NMR and H1-NMR), and gel permeation chromatography (GPC). Monomers were characterized by thermogravimetry (TG). Copolymers were formed only in samples containing 20 wt% å-caprolactone. NMR spectra of the other samples showed no evidence of CL units. This fact may be associated with the low-temperature volatilization of monomers. The GPC analysis showed that the increase of CL concentration decrease the molecular weight of copolymers. Source


Ferreira L.R.M.,Centro Universitario Tupy | Ponte H.A.,Federal University of Parana | Sanches L.S.,Federal University of Parana | Abrantes A.C.T.G.,Federal University of Parana
Materials Research | Year: 2015

This paper discusses the influence of the flow of a fluid from the static regime to the turbulent in CO2 corrosion experienced by low carbon steel. A more comprehensive approach to CO2 corrosion implies taking the free flowing velocity and shear stress of the fluid and the surface roughness of the material into consideration. Low carbon steel samples in two different superficial finish conditions were used as the rotating cylinder electrode. The corrosion rate were determined by linear polarization at 25 °C in a 0.5 mol/L NaHCO3 solution purged with CO2 at 1 atm pressure in pH 7.5. The effect of superficial finish on CO2 corrosion in flow conditions was studied. The results obtained showed that the corrosion rate increases with flow velocity and is influenced by surface roughness. © 2015. Source

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