Melasma is a skin pigmentation disorder characterized by irregular brownish macules, symmetrically distributed in photoexposed areas, most commonly on the face. It is more common in women, with a higher phototype (III-IV) and in fertile age. Due to the high prevalence, the predominantly facial involvement, and the high index of therapeutic recurrence, melasma has an important impact on quality of life, being a frequent cause of dermatological consultations. 1,2 The exact pathophysiology of melasma is not yet known.However, some triggering factors are already well described, such as ultraviolet radiation, pregnancy, use of hormonal therapies, photosensitizing medications, inflammatory stimuli, and stressful events. Genetic factors are also involved, evidenced by the high prevalence of associated family history.

In recent years, the construction of concrete faced rockfill dams (CFRD) has originated discussions concerning the design of concrete slabs in upstream slopes. This stage of design is usually carried out by means of empirical expressions, which determine the thickness of the slab and the steel reinforcement. Nowadays, optimization of the material layers which constitute the rockfill and increase of the dam height are, however, demanding more detailed studies, especially ones related to structural behavior. In this article, using the data from electro-levels installed in the slab of the UHE Machadinho dam, back analysis is applied to identify the Young's modulus (E ) of the material used in a particular zone of the rockfill dam. This study is based on previous ones by the same authors, in which these data were employed to identify the loading parameters of the reaction of the rockfill dam on the concrete face. Structural analyses carried out with the estimated physical parameters are also presentedthese analyses offer valuable information on demanding efforts for the analysis of the concrete slab.

No abstract

No abstract