Enhancement of Corrosion Resistance AISI 304 Steel by Plasma Polymerized Thin Films

The purpose of this work is the deposition of films in order to increase the corrosion resistance of AISI 304 steel, which is a material used to construct the reactors for bioethanol production. This deposition inhibits the permeation of corrosive species to the film-metal interface. Thin films were prepared by radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) method using plasmas of hexamethyldisiloxane/argon/oxygen mixtures excited by signals of different powers. The plasma was generated by the application of RF power of 13.56 MHz to the sample holder while keeping grounded the topmost electrode and the chamber walls. The effect of the RF power on the properties of the samples was investigated by perfilometry, X-ray photoelectron spectroscopy (XPS), contact angle, and electrochemical impedance spectroscopy (EIS). The results of the corrosion resistance tests of the AISI 304 steel were interpreted in terms of the energy delivered to the growing layer by plasma excitation power.

Ultrassonografia modo B de alta resolução modo Doppler e uso de contraste de microbolhas na avaliação testicular de gatos domésticos

Pós-graduação em Medicina Veterinária - FCAV

Características tomográficas de neoplasias encefálicas primárias em cães

Computed tomography (CT) can be considered an important test to identify the presence of primary brain neoplasias in dogs. CT results can help define the type of brain tumor when associated with clinical findings. It allows the identification of lesions and their features, such as size, location, compression and invasion of adjacent tissue. One must analyze the density, mass effect, peritumoral edema, calcification, and image enhancement after intravenous injection of contrast medium. Gliomas, meningiomas and tumors of the choroid plexus and pituitary are the most common primary brain neoplasms diagnosed by CT in dogs. The aim of this paper is to review the literature related to primary brain tumors and report their most important tomographic features, in order to help clinicians achieve a presumptive diagnosis of tumor type.