0000000000612993
AUTHOR
P. Conti
Fatigue crack growth behaviour of four structural steels in air and in a geothermal fluid environment
Abstract In recent years the exploitation of geothermal energy has expanded rapidly in Italy. This has created a requirement for improved drilling technology, to reduce the number of failures occuring in the drills, which is more frequent than in oil wells. This paper deals with the results obtained in FCCR tests of four materials both in air and in two types of aggressive environments. Deterioration takes place by fatigue, corrosion fatigue and hydrogen embrittlement. It is concluded that the steel G105 is a suitable substitute for S135 in drill pipes, and inspections between drillings may be adequate to prevent failure for small-curvature wells.
Matrix metalloproteinase-2 matrix metalloproteinase-9 and inducible nitric oxide synthase in oral leukoplakia: Immunohistochemistry and RT-PCR analysis
Oral leukoplakia is the most common and potentially malignant disorder of the oral mucosa. The definition of leukoplakia given by the World Health Organization is "a white plaque that cannot be characterized either from a clinical or from a histopathological point of view", thus the diagnosis of leukoplakia is based on the exclusion of other lesions of the oral mucosa. We believe it is necessary to identify molecular and immunohistochemical parameters that can contribute to discriminating between the different leukoplakia clinical subtypes coded by the epidemiology. In the present work we show the preliminary results of this research project. We investigated the expression of matrix metallo…
Layer thickness optimisation in a laminated composite
Abstract The paper describes a method to optimise the thickness balance within a composite laminate with layers oriented according to a limited set of angles. The laminate must be symmetric, balanced and loaded in-plane. The optimisation process is particularly suited to be used in conjunction with a finite element program. It provides the designer with the optimal overall engineering characteristics anda list of all the possible orientation combinations ranked with respect to their safety factor. The optimisation method is based on the first order gradient optimum search method and operates iteratively in the engineering elastic characteristics field. The cost function implemented up to no…