Construção, caracterização e aplicação de eletrodos para descarga por arco de cátodo oco

The system built to characterize electrodes and, consequently, deposited fine films are constituted by a hollow cathode that works to discharges and low pressures (approximately 10-3 to 5 mbar), a source DC (0 to 1200 V), a cylindrical camera of closed borossilicato for flanges of stainless steel with an association of vacuum bombs mechanical and spread. In the upper flange it is connected the system of hollow cathode, which possesses an entrance of gas and two entrances for its refrigeration, the same is electrically isolated of the rest of the equipment and it is polarized negatively. In front of the system of hollow cathode there is a movable sample in stainless steel with possibility of moving in the horizontal and vertical. In the vertical, the sample can vary its distance between 0 and 70 mm and, in the horizontal, can leave completely from the front of the hollow cathode. The sample and also the cathode hollow are equipped with cromel-alumel termopares with simultaneous reading of the temperatures during the time of treatment. In this work copper electrodes, bronze, titanium, iron, stainless steel, powder of titanium, powder of titanium and silício, glass and ceramic were used. The electrodes were investigated relating their geometry change and behavior of the plasma of the cavity of hollow cathode and channel of the gas. As the cavity of hollow cathode, the analyzed aspects were the diameter and depth. With the channel of the gas, we verified the diameter. In the two situations, we investigated parameters as flow of the gas, pressure, current and applied tension in the electrode, temperature, loss of mass of the electrode with relationship at the time of use. The flow of gas investigated in the electrodes it was fastened in a work strip from 15 to 6 sccm, the constant pressure of work was among 2.7 to 8 x 10-2 mbar. The applied current was among a strip of work from 0,8 to 0,4 A, and their respective tensions were in a strip from 400 to 220 V. Fixing the value of the current, it was possible to lift the curve of the behavior of the tension with the time of use. That curves esteem in that time of use of the electrode to its efficiency is maximum. The temperatures of the electrodes were in the dependence of that curves showing a maximum temperature when the tension was maximum, yet the measured temperatures in the samples showed to be sensitive the variation of the temperature in the electrodes. An accompaniment of the loss of mass of the electrode relating to its time of use showed that the electrodes that appeared the spherical cavities lost more mass in comparison with the electrodes in that didn't appear. That phenomenon is only seen for pressures of 10-2 mbar, in these conditions a plasma column is formed inside of the channel of the gas and in certain points it is concentrated in form of spheres. Those spherical cavities develop inside of the channel of the gas spreading during the whole extension of the channel of the gas. The used electrodes were cut after they could not be more used, however among those electrodes, films that were deposited in alternate times and the electrodes that were used to deposit films in same times, those films were deposited in the glass substrata, alumina, stainless steel 420, stainless steel 316, silício and steel M2. As the eletros used to deposit films in alternate time as the ones that they were used to deposit in same times, the behavior of the thickness of the film obeyed the curve of the tension with relationship the time of use of the electrode, that is, when the tension was maximum, the thickness of the film was also maximum and when the tension was minimum, the thickness was minimum and in the case where the value of the tension was constant, the thickness of the film tends to be constant. The fine films that were produced they had applications with nano stick, bio-compatibility, cellular growth, inhibition of bacterias, cut tool, metallic leagues, brasagem, pineapple fiber and ornamental. In those films it was investigated the thickness, the adherence and the uniformity characterized by sweeping electronic microscopy. Another technique developed to assist the production and characterization of the films produced in that work was the caloteste. It uses a sphere and abrasive to mark the sample with a cap impression, with that cap form it is possible to calculate the thickness of the film. Through the time of life of the cathode, it was possible to evaluate the rate of waste of its material for the different work conditions. Values of waste rate up to 3,2 x 10-6 g/s were verified. For a distance of the substratum of 11 mm, the deposited film was limited to a circular area of 22 mm diameter mm for high pressures and a circular area of 75 mm for pressure strip. The obtained films presented thickness around 2,1 µm, showing that the discharge of arch of hollow cathode in argon obeys a curve characteristic of the tension with the time of life of the eletrodo. The deposition rate obtained in this system it is of approximately 0,18 µm/min

Sympodiomyces attinorum sp nov., a yeast species associated with nests of the leaf-cutting ant Atta sexdens

Four strains of a novel yeast species were isolated from laboratory nests of the leaf-cutting ant Atta sexdens in Brazil. Three strains were found in older sponges and one was in a waste deposit in the ant nests. Sequencing of the D1/D2 region of the large-subunit rRNA gene showed that the novel species, named Sympodiomyces attinorum sp. nov., is phylogenetically related to Sympodiomyces parvus. Unlike Sympodiomyces parvus, Sympodiomyces attinorum can ferment glucose, assimilate methyl alpha-D-glucoside, salicin and citrate, and grow at 37 degreesC, thus enabling these two species to be distinguished. Differentiation from other related species is possible on the basis of other growth characteristics. The type strain of Sympodiomyces attinorum is UNESP-S156(T) (=CBS 9734(T)=NRRL Y-27639(T)).

Mortalidade de Blattella germanica (L. 1767) (Blattodea: blattellidae) sob diferentes áreas e períodos de exposição a diferentes inseticidas

The great importance of cockroaches as household pest have been on their ability to spread microorganisms harmful to humans and animals. Rest during the day in dark, humid and hot as sewerage. At night go into stores and kitchens or places to deposit and manipulation of food as bakeries, restaurants, hospitals and homes wich requires clinig operations. This work aimed to evaluate mortality of B. germanica ( L., 1767) ( Blattodea: Blattellidae) under different periods and exposure area treated by insecticides in laboratory. The tests were carried out at Department of Fitossanidade at UNESP, Campus of Jaboticabal, SP, Brasil. The insecticides were applied by Potter's tower sprayer on Petri dishes. Three times of exposure (2, 8 and 32 min) and four exposure areas ( 25, 50, 75 and 100%) and volume of 0,5 ml for the second experiment were tested. It was used the insecticides Pyrethroids gammacyalothrine, deltamethrine, lambdacialothrine, alfacipermethrine, cipermethrine and carbamates bendiocarb, in the dosages recommended by the manufacturers, and I was used control without application. Five adult cockroaches was confined in the dishes for both experiments. The mortality evaluation was done 0, 1, 2, 4, 24, 48 and 72 hours after of the confinement on the treated surface. It was concluded that for exposure duration experiment all the insecticides have a good efficiency. The exposure area experiment the insecticide cipermethrine was what the one which had the higher mortality. Regarding to the effect of exposure duration on the accumulated mortality every duration times had a high mortality. In relation to the exposure area the highest mortality reached to 100% of treated area.

Intencionalidades e práticas na construção de metodologias o CEFET-SE

Successive curricular changes that occurred in professional education altered pedagogical practices, and these practices being developed by means of integrating projects, at Centro Federal de Educação Tecnológica de Sergipe (CEFET-SE), between 2001 and 2003, originated some questions which became the study object of this thesis. We search for theoretical support mainly in GEPEM research (GEPEM/UFRN) works and practices in order to analyze elements that emerged from this pedagogical practice. To do so, we take as main reference the research of qualitative approach. We developed documents analysis, interviews, considering three aspects: the scenery where these changes took place, the conception and implementation of the Integrating Projects for what, we ask support in pedagogy of projects studies and principles of interdisciplinary, and contextualization as curriculum structuring elements. This research brought out some difficulties, conflicts and possible consensus in developing the methodological strategies for the Projects. In this process of coexistence of the traditional and the new, of an unavoidable distance between what was thought and what was effectively done, elements for a new pedagogical practice emerged. This could be noticed in terms of participative work, formative moments, teacher s autonomy related to the pedagogical work. A new door could be open to the possibilities of taking conscience of accepting the differences and oneself autoexperimentation. These are the possibilities that make men, not being mere information deposit, can dialog and transform, producing his existence by this means. In the present case, the existence of being teacher, the build himself in the time of possibilities

Tenoplastia experimental do calcâneo em cães com peritônio bovino conservado em glicerina

No presente estudo, avaliou-se a eficácia do emprego do peritônio bovino, conservado em glicerina a 98%, no reparo de lesões induzidas no tendão calcâneo (TC) de cães, quando um fragmento de aproximadamente 1cm do TC foi excisado e o espaço resultante preenchido por um fragmento de peritônio. Foram utilizados 21 cães, pesando entre 10 e 15kg, divididos em 7 grupos de 3, sacrificados aos 02, 07, 15, 30, 60, 90 e 120 dias de pós-operatório. Analisaram-se os aspectos clínico-cirúrgicos referentes à recuperação funcional motora, bem como, a integração do peritônio com o tecido tendíneo mediante avaliação macroscópica, por microscopia óptica e por microscopia eletrônica de varredura. Clinicamente, verificou-se que, por volta do 55º dia de pós-operatório, os animais já apresentavam deambulação normal e que o neotendão apresentou resistência suficiente para suportar o estresse normalmente aplicado ao TC. Microscopicamente, o peritônio implantado esteve presente em todos os períodos de observação. Proliferação fibroblástica e neoformação vascular foram observadas de forma incipiente no segundo dia; entretanto, no sétimo dia de pós-operatório, esta condição foi exacerbada. Com a evolução, as fibras de peritônio tendiam a se dissociar, entrando em estreita associação com fibras conjuntivas, fibroblastos e colágeno. Aos 30, 60, 90 e 120 dias de pós-operatório, notava-se maior presença de colágeno que se tornava cada vez mais organizado. Concluiu-se que o peritônio estimulou uma rápida deposição de tecido conjuntivo com mínima reação inflamatória, sendo incorporado ao tecido cicatricial e servindo como alicerce para o desenvolvimento de um novo tecido, restabelecendo assim a estrutura do tendão.

Depósitos de calda obtidos com a aplicação aérea de defensivos na cultura da banana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)