Made available in DSpace on 2014-08-20T14:38:00Z (GMT). No. of bitstreams: 1 dissertacao_antonella_mattei.pdf: 1371688 bytes, checksum: c8fe587e0a5f75bd8d1e4ecfd0745d85 (MD5) Previous issue date: 2010-02-23 / The aim of this study was isolate filamentous fungi and yeast from veterinary clinics, pet shop and veterinary hospital in Pelotas city/RS and do in vitro test of disinfectants/antiseptics used for clean these places. Surfaces samples were collected from the veterinary hospital before and after the disinfection of the doctor s room, surgery room, internation room and UTI. Samples were collect using contact plates containing agar Sabouraud dextrose added of chloramphenicol, which were incubate at 32ºC during five days. After that, the in vitro susceptibility test against sodium hipoclorite, benzalkonium chloride, chlorhexidine-cetrimide and chlorine-phenol derivate was done. Samples from the pet shop, veterinary room and clinics were collected with brush and blade of shearing machine with swabs and cultured in plates containing Sabouraud dextrose agar added of chloramphenicol and olive-oil and Mycosel® agar, incubated at 25º and 32ºC, for 15 days. In the hospital environment, the filamentous and yeast colonies (CFU/ cm2) was higher in the internation room, showing fungal contamination before disinfection, while the surgical room was the less contaminated. The surfaces studied showed that the stall was the most contaminated before the disinfection, while the trough had a lower contamination. Filamentous fungi grew in 88.9% (192/216) of samples before disinfection, within Aspergillus spp identified in 29.2% (56/192). While, yeasts were recovered in 11.1% (24/216) of samples; corresponding to Candida, Malassezia, Rhodotorula and Cryptococcus genus. After a disinfection, filamentous fungi growth occurred in 73.3%(143/195) of samples, within Aspergillus genus corresponded to 28.7%(41/143). The yeast fungi growth was found in 26.2%(51/195) of samples, and belong to Candida, Malassezia, Rhodotorula and Cryptococcus genus and 0.5% of dimorphic fungi, Sporothrix schenckii. Of these 150 samples through shearing instruments, the fungi growth was observed in 58 samples, within 58.6% (34/58) at blade of shearing machine and 41.4% (24/58) from brush. There, Candida (34.7%), Malassezia (47.5%), Trichosporon (2.5%) e Rhodotorula (15.3%) were the genus identified, noone dermatophytes was obtain. The range of minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) of disinfectants/antiseptics against Aspergillus spp isolates were ≤ 1.25 to > 160 μl/mL and ≤ 1.25 to 80 μl/mL, respectively. Whereas, range of MIC and MFC of disinfectants/antiseptics against Candida, Cryptococcus, Trichosporon and Rhodotorula genus isolates were ≤ 1.25 to 40 μl/mL. In the veterinary hospital environment filamentous fungi and yeast are present. After disinfection a decrease in the fungal contamination occurs, but without statistically significant. About shearing instruments, the blade of shearing machine was the most contaminated part, with a predominance of Malassezia genus. The benzalkonium chloride, chlorhexidine-cetrimide and chlorine-phenol derivated were effective in the use concentration recommended by the manufacturer, while the sodium hypochlorite use concentration did not inhibit fungal growth of 56.1% of isolates tested. / O presente estudo teve como objetivo isolar fungos filamentosos e leveduriformes de clínicas e consultórios veterinários, pet shops e hospital veterinário da cidade de Pelotas/RS, bem como avaliar a eficácia in vitro dos desinfetantes/antissépticos utilizados na limpeza dos locais estudados. Foram realizadas coletas de superfície do hospital veterinário antes e após a desinfecção da sala do consultório, sala cirúrgica, internação e UTI, através de placas de contato contendo ágar Sabouraud acrescido de cloranfenicol, incubadas a 32ºC por cinco dias, para obtenção de unidades formadoras de colônias (UFC). Posteriormente, foi realizado o teste de suscetibilidade in vitro dos isolados fúngicos frente ao hipoclorito de sódio, cloreto de benzalcônio, clorexidina-cetrimida e derivado cloro-fenol. Em pet shops, consultórios e clínicas veterinárias também foram coletadas amostras de rascadeiras e lâminas da máquina de tosa através de swabs estéreis e impressão em placas contendo ágar Sabouraud acrescido de cloranfenicol e azeite de oliva e ágar Mycosel®, incubadas a 25º e 32ºC, por até 15 dias. No ambiente hospitalar, a contagem das UFC/cm2 filamentosas e leveduriformes foi maior na sala de internação antes da desinfecção, enquanto que, a sala cirúrgica foi a menos contaminada. A análise das superfícies demonstrou que a baia era a mais contaminada antes da desinfecção, enquanto que a calha apresentava menor contaminação. O crescimento de fungos filamentosos ocorreu em 88,9%(192/216) das amostras antes da desinfecção, identificado Aspergillus spp em 29,2%(56/192). Já o crescimento de fungos leveduriformes ocorreu em 11,1%(24/216) das amostras, com os gêneros Candida, Malassezia, Rhodotorula e Cryptococcus. Após a desinfecção houve crescimento de fungos filamentosos em 73,3%(143/195) das amostras, sendo identificado o gênero Aspergillus em 28,7%(41/143). O crescimento de fungos leveduriformes ocorreu em 26,2%(51/195) das amostras, pertencentes aos gêneros Candida, Malassezia, Rhodotorula e Cryptococcus e 0,5% foi o percentual de isolamento de fungo dimórfico, Sporothrix schenckii. Das 150 amostras obtidas dos instrumentos de tosa, o crescimento fúngico ocorreu em 58 amostras, sendo 58,6% (34/58) referentes à lâmina da máquina de tosa e 41,4% (24/58) a rascadeira. Foram identificados os gêneros Candida (34,7%), Malassezia (47,5%), Trichosporon (2,5%) e Rhodotorula (15,3%), porém não foram isolados dermatófitos. A concentração inibitória mínima (CIM) e concentração fungicida mínima (CFM) dos isolados de Aspergillus spp frente aos quatro desinfetantes/antissépticos variaram de ≤ 1,25 a > 160 μl/mL e ≤ 1,25 a 80 μl/mL, respectivamente. Enquanto que, tanto a CIM e CFM dos isolados dos gêneros Candida, Cryptococcus, Trichosporon e Rhodotorula frente aos quatro desinfetantes/antissépticos, variaram de ≤ 1,25 a 40 μl/mL. Os resultados obtidos permitem concluir que, no ambiente hospitalar veterinário estão presentes fungos filamentosos e leveduriformes e após a desinfecção houve redução da contaminação fúngica, porém não apresentando diferença estatística significativa; considerando os instrumentos de tosa, a lâmina da máquina de tosa foi a mais contaminada, com predominância do gênero Malassezia; a clorexidina-cetrimida, cloreto de benzalcônio e derivado de cloro-fenol foram eficazes na concentração de uso indicada pelo fabricante, enquanto que o hipoclorito de sódio na concentração de uso não inibiu o crescimento fúngico de 56,1% dos isolados testados.

Les matériaux énergétiques sont, par définition, des matériaux susceptibles de dégager un volume important de gaz, en se décomposant via les phénomènes suivants : combustion, déflagration ou détonation. Ils sont notamment utilisés dans les secteurs industriels de l’automobile (déploiement d’airbag), du militaire (propulsion de missiles tactiques et stratégiques, munitions) et du spatial (boosters de lanceurs spatiaux type Ariane 5). La maîtrise de leur fabrication nécessite que soient vérifiées certaines contraintes spécifiques rencontrées lors de leur mise en œuvre dans un malaxeur bivis. En effet, ce procédé de malaxage en continu induit de fortes évolutions de gradients de pression et de cisaillement au sein du matériau énergétique (entrefers réduits...) qui peuvent initier les constituants fluides et solides. Par conséquent, dans un souci de parfaite maîtrise des risques industriels, les conditions tribologiques menant à l’initiation d’un matériau énergétique, ici le propergol, lors de sa fabrication, doivent être étudiées. Malheureusement, à cause de la confidentialité industrielle liée à ce secteur d’activité, la bibliographie de la tribologie des propergols est limitée. Il apparait toutefois que peu d’études portent effectivement sur le comportement tribologique du troisième corps, c’est à dire le propergol. Ce dernier étant hétérogène (mélange de constituants fluides et de solides), il est donc nécessaire d’appréhender les écoulements internes qui l’animent sous sollicitations tribologiques. Ainsi, pour reproduire les sollicitations mécaniques élémentaires (compression et cisaillement) appliquées par les deux premiers corps que sont les vis et le fourreau, et subies par le troisième corps lors du malaxage, il a été choisi d’utiliser une approche couplée expérimentale et numérique. Cette dernière s’organise autour de l’instrumentation d’un dispositif de sécurité permettant la sollicitation par frottement du propergol et de la modélisation par éléments discrets du triplet tribologique (parois supérieure et inférieure des premiers corps, et troisième corps). Il est ainsi apparu un comportement tribologique caractéristique du troisième corps : des ségrégations entre les constituants mènent à un arrangement selon trois couches superposées dans l’épaisseur du troisième corps. Ces ségrégations sont issues de la mise en place de débits internes, spécifiques à chaque nature et géométrie de constituants. Ces débits sélectionnent les constituants présents dans l’aire de contact et favorisent l’existence de conditions tribologiques favorables à l’initiation du troisième corps (assèchement de l’épaisseur, localisation des efforts appliqués au troisième corps ...). L’ensemble de ces débits permet de reconstituer un circuit tribologique d’initiation d’un propergol et ainsi d’envisager des solutions techniques permettant d’endiguer la mise en place des conditions défavorables à la fabrication en sécurité d’un propergol dans un malaxeur bivis. / By definition, energetic materials can deliver a huge amount of gas and cause different kinds of phenomena, such as: burning, deflagration or detonation. These materials are mainly used in the automotive industry (airbag deployment), military devices (missiles, ammunition) and space launchers (Ariane 5 boosters and pyrotechnic devices). The manufacturing process, although well controlled by the historical “batch” process, presents several challenges when it is transferred to the continuous mixing process, using a twin-screw mixer device. Indeed, this last device induces extreme evolutions of pressure gradients and shearing gradients (reduced air-gap...). Plus, the energetic material is composed of fluid components and different diameters of solid components that can ignite by shearing. Consequently, tribological conditions leading to the ignition of an energetic material, a solid propellant, are studied during its manufacturing in a twin-screw mixer. Unfortunately, because of the industrial confidentiality on solid propellants, the bibliography on the solid propellants tribology is limited. However it appears that too few studies have effectively dealt with the tribological behaviour of this third body. By nature, this last is a composite material; therefore it is necessary to understand internal flows that evolve from tribological stresses. Thus, a coupled approach experimental and numerical is chosen in order to reproduce the mechanical elementary stresses applied by the two first bodies (top of screw thread and bore of the barrel element), and undergone by the third body during its manufacturing in a twin-screw mixer (compression and shearing). This approach consists of the instrumentation of a security test that shears the solid propellant and a discrete element simulation of the tribological triplet (inferior and superior first bodies, and the third body). The distinctive tribological behaviour of this third body appears obvious: different types of component segregations lead to a three superposed layer arrangement of the solid propellant thickness. These segregations come from the creation of internal component flows, specific to the nature and the geometry of the third body components. These flows select the components that remain within the contact area and also establish the tribological conditions that favour the third body ignition (gradient of mobility between solid components, draining of the third body thickness, localization of the efforts applied to the third body…). Ultimately, this study rebuilds the ignition tribological circuit(s) of a solid propellant and offers technical solutions to prevent the materialisation of unfavourable conditions to a safe solid propellant manufacturing in a twin-screw mixer.

In this master's thesis the proposal of the production technology of component – solar collector anchor element from steel 1.0038 (11 375) quality, 5 mm thickness is solved. For the manufacturing of the assigned part the shearing and bending technology and a progressive forming tool including a suitable forming machine of 8,000 kN rated power is selected. The proposed method of production is laid down by a technical-economic evaluation with respect to the production series of 150,000 units per year. The solar collector anchor element serves to hold the frame for the solar vacuum tube collector. In the scope of this master's thesis, an assessment of the current production method, including the selection of a suitable semi-finished product for production, was also carried out and their optimization was proposed.

The project elaborated design of technology production of the filter cover - section from the deep drawing sheet 11 325 (DC04). Based on analysis was chosen combination of technologies shearing and deep drawing for that option was designed manufacturing process. Forming process is realized on hydraulic progressive press from Sweden company AP&T which has got total nominal tensile force 1740 kN and equipped 5 stations with lower holders and upper ejectors. Deep drawn part is transported between stations by feeders which are part of press. Function parts are made from alloyed tool steels 19 436 and 19 573 which are heat-worked according to drawing documentation. In chapter technical and economical evaluation was determined turning point which become after reaching of 142 840 parts.

This diploma thesis aims to verify the properties of lead-free solders, which are subjected to accelerated aging by thermal cycling. The theoretical part describes in detail the most used lead-free solders and their characteristics. The next section describes fluxes and their important functions in the soldering process. Intermetallic compounds are also mentioned, which significantly affect the quality and service life of the soldered joint. In the practical parts, the test motif was on two different substrates - corundum ceramics and the widely used substrate FR-4 (Glass fiber fabric saturated with epoxy resin). SAC solder was chosen as the reference solder for the experiment, followed by solder containing bismuth (Sn42 / Bi58) and lead solder (Sn62 / Pb36 / Ag2). Accelerated aging by thermal cycling was performed in the temperature range from -20 ° C to 125 ° C, followed by performing a test of the mechanical strength of the soldered joint by means of a shear test. SnBi solder shows higher mechanical strength at the beginning of testing than SAC solder and lead solder, during temperature cycles, it significantly loses its mechanical properties, this is caused by increasing oxidation of the alloy. SAC solder seems to be promising, which has an almost constant decrease in mechanical strength during all temperature cycles on both corundum and FR-4 substrates.

The project drawn up within engineering studies, field M-STG, presents a design for processing a single part – the part is made of sheet steel number S195T by shearing and bending. On the basis of literary study was design compound tool which is working in three steps. The tool is fixed in eccentric press LE 250 with nominal force 25000 kN. Blanking punch and blanking die are made from tool steel 1.2379 according the drawing documentation.

The project, which has been elaborated within the framework of Master's Degree in Manufacturing Technology (2303T002), processes a technology proposal for the production of stamped part čelo from DD14 material, with a thickness 4 mm, with production quantities of 100 000 pieces per year, in cooperation with the company UNIRON Ltd. Based on the literature study of deep drawing without thinning of the walls and calculations, production of the part of simple single-function drawing tools was proposed. The first three operations performed on a PYE 100 S/1 hydraulic press and the last calibration operation carried out on a LEK 250 eccentric press. The semi-finished product is blank with a diameter of 195 mm, produced in a simple cutting die. The cutting die is designed for both the material in the form of a sheet metal strip in coils and cut strips of metal sheet, which is associated with the use of two eccentric presses of the LEK 250 and LE 400C types. The proposed manufacturing process was simulated in the PAM-Stamp 2G software, in which the influence of the radius the functional parts of tools to change the thickness of the material is further simulated. The part of the project is a technical and economic evaluation, in which the price of one piece of the product and production quantity at which production becomes profitable was rated.

The wavefront reconstruction of a light wave transformed by a microscope objective is the main subject of this diploma thesis together with the design and assembly of a~measuring device and the development of a computational algorithm. The purpose is to determine optical aberrations and to compare a quality of objectives with identical parameters. The term wavefront is explained and its description using Zernike polynomials is introduced in the first part of the thesis. The following part summarizes possible methods for wavefront reconstrucion. Two methods were chosen for experimental determination of a wavefront shape – shearing interferometry and solution of the transport of intensity equation. For each method a brief characteristic is provided together with possible applications, mathematical apparatus, image processing, computational procedure, setup description and proposition and results of experiments. The suitability of both methods for optical aberration determination and microscope objective comparison is discussed. Based on the obtained results, both methods were found to be suitable for comparison of microscope objectives. The suitability for optical aberration determination is possible with certain restrictions.

The wall clamp is used for attaching columns or pillars to a concrete foundation. It is made from structural steel 11 375 in the form of sheets with a thickness of 4 mm in the production run of 150 000 pcs/year. A combination of shearing and bending technologies in a progressive forming tool was selected from various options as the most appropriate. On the basis of structural and technological calculations, an instrument was designed, for which the technical documentation was elaborated. Due to the total forming force and work, the forming machine LDO 800 A/S from Šmeral Brno a.s. was selected as the manufacturing machine. The production cost per one part 53.66 CZK was determined using economic evaluation; based on the break even point, the production becomes profitable for the production run with the minimum number of 13 065 pcs.

Gegenstand der Dissertationsschrift ist eine Darstellung des gegebenen Wissensstandes zum Scherschneiden anhand der Literatur, mit einer Einordnung des Schrägschneidens. Auf dieser Grundlage erfolgt eine Verfahrens- und Prozeßbeschreibung des Schrägschneidens, als Variante des Scherschneidens, insbesondere eine Untersuchung des auftretenden Verschleisses. Es wird die Anwendung des Laser-Pulver-Auftragschweißen an Schneidwerkzeugen zur Verschleißminimierung erprobt und bewertet.