Fernando B. Mainier

Corrosion in surgical instruments

The surgical instruments that are on the market for use in medical and dental treatments, most of which are designed for specific actions in specific types of surgery, are usually manufactured from stainless steels, including AISI-420 and AISI-304, as well as titanium alloys. They are manufactured by many different companies, which means that the materials used to make them have a variety of sources, types of alloys, material quality, mechanical fabrication processes and costs. Surgical instruments are subject to contamination, or bacterial adherence to the instruments, from various sources, which can have an enormous impact on human health. Hospitals and clinics are well-suited environments for this to happen, since they concentrate both particularly susceptible hosts and highly resistant micro-organisms. Therefore, cleaning and sterilization of all surgical instruments after each use is essential. Typically, steam autoclaves and solutions of chlorine-based oxidants or similar chemicals are used. These methods of cleaning can cause premature deterioration of the instruments, reducing their lifespan. Unannounced inspections of hospitals often detect instruments containing small fractures, microscopic cracks, pitting, and crevices that should invalidate their use in surgery. The objectives of this study are to identify the types of corrosion that occur in the process of sterilization and to critically assess the matter in relation to the costs of the instruments available in the Brazilian market. Finally, this study aims to clarify and publicize the problem of the quality of surgical instruments that can be used in hospitals, possibly compromising the health of the population.

Ship hull corrosion caused by default and lack of maintenance on the impressed current cathodic protection

This article presents a case study of corrosion of a ship hull that began after continuous failure of the impressed current cathodic protection system. The purpose of this article is not to question or criticise the design, installation, maintenance, or operation of the cathodic protection system, but only to show through the inspection carried out that the main aspects of the corrosive process that occurred when it was anchored for more than six months. In order to leave the ship in normal operating conditions, repairs were conducted that consisted of cleaning with pressurised water blasting, welding repair of corroded plates, paint application, and installation of zinc anodes in cathodic protection replacement.

Análise da resistência à corrosão por pite em soldas de reparo pelo processo TIG em aço inoxidável superduplex UNS S32750

Atualmente, os acos inoxidaveis superduplex (AISD) estao sendo muito empregados no Brasil em setores industriais tais como petroquimico, energetico, naval e plataformas offshore, tendo vasta aplicacao em vasos de pressao em processos criticos, trocadores de calor, reatores, tubulacoes, umbilicais, digestores, bombas e naqueles componentes onde a produtividade continua e essencial e o custo nao e a maior limitacao. No entanto, durante processos de fabricacao e montagem, assim como na vida em servico destes componentes de processo pode existir a necessidade eventual de efetuar soldagens de reparo. Deste modo, o presente trabalho, visa avaliar a microestrutura e os valores de resistencia a corrosao por pites na zona termicamente afetada (ZTA) e metal de solda do AISD UNS S32750 durante a simulacao de um processo de reparo mediante a utilizacao do processo de soldagem TIG (GTAW). Os resultados obtidos permitem estabelecer diretrizes para a realizacao de procedimentos de soldagem de reparo em AISD.

The Management of Knowledge in the School Context and the continued Training of Teachers in Service

The present work analyses the administration within a school organization from a pedagogical perspective, understanding that pedagogical coordination acts with the management, being responsible for coordinating the progress of the work in the organization, ensuring the articulation of interpersonal relations, the conditions for the personal and professional development of the people of the school. The research was carried out in one school maintained by Brazils federal government, located in the city of Rio de Janeiro that is attended exclusively by students in the initial years of fundamental education. As instruments of data collection, a structured interview and a semi-open questionnaire were used. The obtained data were worked quantitatively, using percentage frequency, and qualitatively, using content analysis. It was concluded that, using knowledge management strategies, several opportunities for continuing teacher training in service take place in the planning meetings of the schools teaching team and considering that, the pedagogical actions are also planned in these meetings

Critical Evaluation of Individual Hearing Protectors of Workers in Civil Construction

The hearing protection of workers is of great concern to occupational health and safety professionals because of the irreversible damage caused by prolonged exposure to noise. This work seeks to determine whether the hearing protection equipment used in the construction industry today is adequate, considering that, in addition to the intense noise, other risk factors are present in the typical environment of a construction site. For this, a survey was conducted on how workers in the industry recognise and prevent exposure to noise and how they use hearing protection. Subsequently, laboratory experiments were used to study, how the main contaminants interact with the material of which this equipment is composed. In laboratory tests, both foam and silicone plugs gained weight when exposed to contaminants typically found in construction. This fact evidenced the need for training regarding the hygiene of hearing protectors. Regarding the performance of the foam earplugs in the tests, it was verified that, even though they went through the cleaning process, the equipment also increased in mass. This fact demonstrates that cleaning helps but does not eliminate the contamination of the hearing protection devices (HPD). Finally, it was concluded that the both types of earplugs are efficient in relation to noise attenuation and protection of the hearing of the workers. However, the way they are used and cleaned can influence the contamination of these protectors and the research detected both a lack of information from the manufacturers and little or no training of the workers.

Propargyl alcohol as a corrosion inhibitor for AISI 304L stainless steel in hydrochloric acid

Hydrochloric acid solutions (at concentrations of 5 to 28%) are used to acidify or acid-stimulate a rock-reservoir, increasing productivity of an oil well and removing calcareous deposits that lodge inside the carbon steel pipes. Typically, AISI 304 L stainless steel is used to manufacture various components, such as valves, adapters, rings, connectors, and rotors of pumps that are used in these acidifications. In order to guarantee the protection of both the carbon steel and the AISI 304 L, propargyl alcohol can be used as a corrosion inhibitor. The results of mass loss (gravimetric) and electrochemical tests (polarization curve) show a good efficiency of propargyl alcohol as a corrosion inhibitor for AISI 304 L stainless steel in concentrations of 5% (by volume) and 10% (by volume) of hydrochloric acid.

Determination of Resistance Parameters of Contaminated Compacted Tropical Soils in the State of Rio de Janeiro

Direct shear (DS) tests with controlled shear rates were performed in two soils from the Baixada Fluminense region, in the city of Sao Joao do Meriti – Rio de Janeiro, Brazil. The first soil characterized as Inorganic Clay of high plasticity (CH) was located in a hillside region. The second soil characterized as medium plasticity clay (CL) was located in a central region of the studied area with a slight slope. The soils in question are deposited on non-compacted soft soil with the addition of Municipal Solid Waste (MSW). Both samples of compacted soil were excavated at a depth of 1.0 m, and undisturbed samples were collected. In addition to the previously mentioned tests, oedometric tests and soil physical classification tests were carried out to evaluate geotechnical parameters. In both tests the shear rate of 0.043 mm / min was adopted. The tests presented coherent results with probabilistic accuracy greater than 95% inreliability compared to three tests with compacted tropical soils.

Evaluation of the planning of pedagogical actions in the fundamental school

Currently, the construction of knowledge forces a new posture of the teacher in Elementary Schools, requiring a broader view and interaction in the various areas, where knowledge management becomes mandatory. This article aims to evaluate the pedagogical management applied in a fundamental school with about 250 students, located in Rio de Janeiro, Brazil, using interviews and questionnaires with teachers. With this research it was possible to conclude that teachers perceive the existence of several conditions that favour the creation, dissemination and socialization of knowledge, considering the good professional relations existing between the teachers who work in the classroom and the pedagogical team.

Chromate and the Environment: Removal and Utilization of Industrial Waste

Chromate and dichromate sodium as a function of oxidizer characteristics are used in several industrial areas; for example, in surface protection of coated parts of cadmium, zinc and aluminum (chromate coated treated), corrosion inhibitors, the treatment of leather, the manufacture of pigments, etc. However, the use of such products has been questioned due to the problems of toxicity and pollution that can be caused in the environmental. The Brazilian environmental agency has established that the concentrations of chromate in water courses are less than 0.5 ppm. In order to reuse chromate (CrO4) from industrial effluent, laboratory experiments have been proposed based on chemical reduction or electrolytic processes, in order to transform these chromate ions in a final mix of oxides (in solid form), which can then be packed and sent to the production process of sodium chromate. The results of these experiments have become useful industrially (without regard to costs) considering the environmental reuse and the life cycle of the chemical compound.

Impact of Deterioration of Flare of an Offshore Oil Platform

The importance of the study of the impacts of deterioration in the flare of an offshore platform is based on the fact that the corrosion and failures of the components of the flare cause the occurrence of emergency shutdowns for maintenance, causing great economic losses. In addition, it is essential to be alerted that by operational issues of security, at all levels, the offshore rig that cannot produce oil and gas flare is not reliable; because of operating conditions, the risk of fire and explosion are inevitable. Here, potential damage conditions are identified in the structure of flare as well as in an evaluation of failures due to material cracking and degradation. Monitoring alternatives are proposed to avoid or reduce the emergency stops on the offshore platform.