DSpace Coleção:
http://repositorio.ufc.br/handle/riufc/508
2024-03-29T08:19:43ZConfiabilidade metrológica no contexto da garantia da qualidade industrial: diagnóstico e sistematização de procedimentos
http://repositorio.ufc.br/handle/riufc/66880
Título: Confiabilidade metrológica no contexto da garantia da qualidade industrial: diagnóstico e sistematização de procedimentos
Autor(es): Soares Júnior, Luiz
Abstract: The requirements for the reliability of measurement results and the formality of
measurement procedures have increased significantly since the establishment of ISO 9000
certification. It is well known that many Brazilian companies approach metrology in an
inappropriate way. The root of this problem could be understood as a lack of metrological
culture in ours industries. Also, it’s weak in the academic areas the culture to show the
industry the role of the metrology as a key for quality. In addition, the ISO 9000 family of
standards does not contribute to clarify the metrological subject by itself, i.e., requirements
for the ISO 9000 implementation are set without any kind of explanation or justification. To explore the gap between metrology practices in the Brazilian industry and the
standardization in industry, two blocks of information have been compared. Standards,
procedures and technical papers have been analyzed to define the state of the art regarding
the application of the metrology in quality assurance. A survey has been conducted in
fifteen companies certified with the ISO 9000 to define the level of application of
metrological knowledge. The result of the above study shows, in many cases, the absence
of a methodology for implementation of metrological systems and the lack of adequate
knowledge of metrology to establish metrological procedures.
Solutions are proposed to narrow the gap between the actual and the desired states
of metrological reliability in the Brazilian industry. Whenever it is possible, the solutions
are based on formal documents issued by the ISO. In order to simplify their application in
actual industrial situations, a methodology for the implementation of metrological quality
assurance has been proposed. Its feasibility has been tested by means of a real case study. This methodology provides the basis for a “Guide to Metrological Reliability”,
designed to support metrology management in ISO 9000-certified companies. The basic
structure of such Guide is presented in this dissertation as a hypertext, which can be used
to diffuse the concept among the whole Brazilian territory using the Internet.
Tipo: Dissertação1999-01-01T00:00:00ZCaracterização Experimental do Efeito de um Bocal com Chevron sobre o Campo Turbulento de um Jato Subsônico
http://repositorio.ufc.br/handle/riufc/62038
Título: Caracterização Experimental do Efeito de um Bocal com Chevron sobre o Campo Turbulento de um Jato Subsônico
Autor(es): Maia, Igor Albuquerque
Abstract: The turbulent jet issuing from engine exhaustion is one of the
main sources of noise in an aircraft. This is a topic in the research
field of aeroacoustics in which the sound generation mechanisms
are not yet fully understood. However, some noise reduction
devices have been developed and applied in aircrafts, such as tabs
and chevrons. The present work addresses a comparison between
the flow fields generated by nozzles with and without chevrons
through hot-wire anemometry. The main goal was to understand
the chevron effect on the flow field and the noise reduction
mechanisms attributed to such nozzles. The results have shown an
increase in axial turbulent intensity generated by the chevron in the
initial region of the jet (x/D<2) and a decrease in turbulent intensity
levels in the subsequent region. The chevron nozzle also increased
the spreading of the jet and generated a thicker shear layer. The
power spectral density showed the existence of coherent structures
in the jet and the chevron was found to affect the energy peaks
associated to these structures, specially at Strouhal number 0.3.
Tipo: Dissertação2015-01-01T00:00:00Z