RESUMO
Automobile laser brazing remains a complex process whose results are affected by several process variables that may result in nonacceptable welds. A multisensory customized inspection system is proposed, with two distinct non-destructive techniques: the potential drop method and eddy current testing. New probes were designed, simulated, produced, and experimentally validated in automobile's laser-brazed weld beads with artificially introduced defects. The numerical simulations allowed the development of a new four-point probe configuration in a non-conventional orthogonal shape demonstrating a superior performance in both simulation and experimental validation. The dedicated inspection system allowed the detection of porosities, cracks, and lack of bonding defects, demonstrating the redundancy and complementarity these two techniques provide.
RESUMO
This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.
Assuntos
Poluentes Atmosféricos/química , Tamanho da Partícula , Material Particulado/química , Soldagem , Poluição do Ar em Ambientes FechadosRESUMO
Defect detection in additive manufacturing (AM) is of paramount importance to improve the reliability of products. Nondestructive testing is not yet widely used for defect detection. The main challenges are a lack of standards and methods, the types and location of defects, and the complex geometry of many parts. During selective laser melting (SLM), several types of defects can occur such as porosity, cracking, and lack of fusion. In this study, several nondestructive tests were conducted in a highly complex shaped part in AISI 316L stainless steel with real defects manufactured by SLM. Two additional artificial defects (one horizontal and one flat bottom hole) were produced and the defect detectability was evaluated. The techniques used were as follows: dye penetrant, infrared thermography, immersion ultrasonic, eddy current, and X-ray microcomputed tomography to assess different types of defects in the as-built part. We conclude that no single technique can detect every type of defect, although multiple techniques provide complementary and redundant information to critically evaluate the integrity of the parts. This approach is fundamental for improving the reliability of defect detection, which will help expand the potential for using AM to produce parts for critical structural applications.
RESUMO
In an increasingly miniaturised technological world, non-destructive testing (NDT) methodologies able to detect defects at the micro scale are necessary to prevent failures. Although several existing methods allow the detection of defects at that scale, their application may be hindered by the small size of the samples to examine. In this study, the application of bacterial cells to help the detection of fissures, cracks, and voids on the surface of metals is proposed. The application of magnetic and electric fields after deposition of the cells ensured the distribution of the cells over the entire surfaces and helped the penetration of the cells inside the defects. The use of fluorophores to stain the cells allowed their visualisation and the identification of the defects. Furthermore, the size and zeta potential of the cells and their production of siderophores and biosurfactants could be influenced to detect smaller defects. Micro and nano surface defects made in aluminium, steel, and copper alloys could be readily identified by two Staphylococcus strains and Rhodococcus erythropolis cells.
RESUMO
Propósito: El Propósito de este estudio es conocer de que manera se organiza actualmente la estructura de enfermería en el marco de las reformas del sector salud. Antecedentes: Los diferentes cambios sociales y económicos que le ha tocado vivir a la sociedad Centroaméricana como consecuencia de la crísis económica, implantación de medidas de ajuste económico han originado la necesidad de una revisión de la forma y de los recursos con que se han venido brindando los servicios de salud a la población. Según la Organización Mundial de la Salud (1994) al examinar la necesidad del personal de enfermería se deberá tomar en cuenta los problemas mundiales actuales. "Esta situación económica y social orientan a reflexionar en la salud como un derecho de los pueblos que contribuye el concepto de equidad reduciendo la brecha social favoreciendo el desarrollo de los países, lo que constituye un reto para el personal de salud donde enfermería juega un papel de mucha trascendencia" (Olivas et al 1996). Las enfermeras constituyen el grupo más importante en número del personal dedicado a la atención en salud. En Nicaragua desde la década de los ochenta el sector salud ha sufrido varias transformaciones en consonancia con las diferentes coyunturas por las que ha transitado el país. Este proceso de cambio del sector salud involucra a enfermería como miembro del equipo de salud y frente a esta situación la estructura de enfermería sufre ajustes periódicos en su organización y trata de responder a las demandas de la población. Como enfermeras debemos considerar la orientación cambiante de la atención de salud en todo el mundo como consecuencia de la nueva tecnología y las exigencias crecientes. Resultados: Basadas en encuestas realizadas a 28 enfermeras(os) del Hospital Manolo Morales los resultados indicaron que existe poco conocimiento de parte del gremio en cuanto a la implementación de la nueva estructura de enfermería frente a las reformas del Ministerio de Salud. Resultados Principales: No existen estudios anteriores que sirvan de base para el desarrollo de este trabajo en relación al conocimiento sobre la organización de la estructura de enfermería en el proceso de reformas del sector salud. Este estudio señala que las enfermeras opinan que la actual estructura es adecuada y que responderá ante las demandas de la implementación de las reformas...