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Souza-Bastos L.R.,Federal University of Parana | Bastos L.P.,Institute Tecnologia para o Desenvolvimento | Freire C.A.,Federal University of Parana
North American Journal of Aquaculture

Abstract: Silver Catfish Rhamdia quelen, a native South American catfish relevant in intensive culture systems in Brazil, were exposed to three ammonia concentrations added to the water (0.5, 1.0, and 2.0 mg/L as ammonium chloride). After 5 and 24 h, measured water ammonia levels increased to maximum levels of 15.8–41.1 mg/L, reflecting the addition of ammonia excreted by the fish. Aquaria were aerated but kept closed, and pH and temperature were kept constant. Hematocrit, plasma ammonia, osmolality, Na+, Cl−, K+, glucose, and cortisol were assayed. Branchial and muscle hydration levels and branchial and renal specific activities of the carbonic anhydrase (CA) were determined. Silver Catfish did not show stress responses or signs of osmoregulatory disturbance upon the increased water ammonia levels. However, there was inhibition of the CA in gills and kidneys, especially after 24 h, in a dose-dependent manner to the total ammonia accumulated in the water. Although Silver Catfish are tolerant of increase in ammonia, care should be taken to limit increases in ammonia levels and time of exposure because the severity of the deleterious effects will certainly increase. In addition, results have shown that the fish carbonic anhydrase (branchial and renal) is a sensitive biomarker of effect of ammonia. Received June 17, 2014; accepted August 25, 2014. © 2015, © American Fisheries Society 2015. Source

Pukasicwicz A.G.M.,Federal Technological University of Parana | de Oliveira F.R.,Federal Technological University of Parana | Capra A.R.,Institute Tecnologia para o Desenvolvimento | Paredes R.S.C.,Federal University of Parana
Soldagem e Inspecao

ASTM A743-CA6NM martensitic stainless steel have been used in hydraulic turbines manufacturing, but show some restrictions in welded recovered areas. Different techniques have been applied in order to reduce or eliminate residual stress, with life increase. The deposition of cavitation resistant coatings is another important way to increase the service life of these components. The objective of this study is evaluate the influence of type and intensity of plasma remelting current on the microstructure, chemical composition and microhardness of the Fe-Cr-Mn-Si cavitation resistant coatings deposited by arc thermal spray process on CA6NM steel. It was observed that lower level of current, as well as, the use of pulsed current reduce ferrite 8 layer and HAZ thickness, reducing base metal modifications during coating remelting. It was observed that base metal dilution alterations did not promote any significant modification on microstructure and microhardness of the remelted coatings. Constant arc remelting current promoted a microstructure alignment with plasma torch dislocation, this behavior was not observed in pulsed current remelted coatings. Source

Tessaro A.B.,Federal University of Pelotas | Tessaro A.A.,Uniao de Ensino Do Sudoeste Do Parana UNISEP | Cantao M.P.,Institute Tecnologia para o Desenvolvimento
Revista em Agronegocio e Meio Ambiente

The breeding of confined broilers produces wastes that cause environmental problems. They require different management procedures since they may generate great environmental impact and consequently disposal for the residues produced. Current paper assessed the energy capacity of broiler litter used as a substrate for the production of biogas in the southwestern region of the state of Paraná, Brazil. A qualitative, quantitative and exploratory research was undertaken for data in specific bibliographies on the subject and the characterization of poultry production in the region. Poultry biomass was characterized chemically and later evaluated in three treatments to determine the capacity for biogas production. Results showed that the southwestern region of the state of Paraná produces 39,173,367 broilers/year in 38 municipalities, with 51,219.17 tons of biomass in the form of broiler litter/year. The biomass, comprising nitrogen, phosphorus, potassium calcium, magnesium and sulfates, produces biogas in the three treatment systems under analysis, although the second treatment was the most viable. The biofertilizers, with pH between 6.58 and 8.02, proved to be rich in macro- and micro-nutrients, mainly nitrogen, phosphorus, potassium calcium, magnesium, sodium, iron, boron, copper, zinc and manganese. Biomass from broiler litter may be a viable alternative in the production of biogas which will be capable of replacing traditional fuel and electric energy in poultry-breeding farms in the region. Source

Honnicke M.G.,Iguacu University | Godoi W.C.,Federal Technological University of Parana | Swinka-Filho V.,Institute Tecnologia para o Desenvolvimento
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films. © 2014 Elsevier B.V. Source

Munhoz-Rojas P.E.,Institute Tecnologia para o Desenvolvimento
Progress in Electromagnetics Research Symposium

An axiomatic reformulation of Maxwell's theory of electromagnetism is presented that permits to deduce Maxwell's theory and, also, most of the well known theories of classical electromagnetism. As a result it is shown that these theories are not fully equivalent. It is shown that, independently of the existence or inexistence of free magnetic poles, Maxwell-Hertz's equations are valid microscopically. It is also shown that all interaction processes involve an "electric quantity" and a "magnetic quantity". Using these concepts, a theory of the interaction between fields and macroscopic matter is presented, which extends the well known Maxwell-Lorentz's theory. As a result, it is shown that Maxwell's theory of light propagation in a non-conducting medium concerns the interaction between bound magnetic charges and bound electric charges, which is a phenomenon totally different from the electromagnetic perturbations that are attached to metallic conductors, where the excitation is due to free electric charges moving inside the conductor. It is believed that these results, besides its academic interest, could be useful for the design and interpretation of the functioning principle of antennas and sensors. Source

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