OBJECTIVE The aim of this paper was to determine the amount of deformation in four commercial brands of nickel-titanium closed springs. METHODS A total of 130 springs were divided into 13 subgroups, according to their features and manufacturers (Morelli, Orthometric, Ormco and GAC) and activated from 100% to 1000% of the effective length of the nickel-titanium portion present at the spring, a...

The identification and characterization of genes involved in the microbial oxidation of arsenite will contribute to our understanding of factors controlling As cycling in natural systems. Towards this goal, we recently characterized the widespread occurrence of aerobic arsenite oxidase genes (aroA-like) from pure-culture bacterial isolates, soils, sediments and geothermal mats, but were unable ...

Three Chlamydomonas strains were isolated from the soils of a hot spring located in the Campi Flegrei Caldera (Naples, Italy). Ecophysiological, morpho-cytological and molecular features were used to characterize these isolates and to compare them with chlamydomonax acidophila strains from algal culture collections. The strains were collected from three points of the volcanic site, differing in...

Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8-11 µg/g), which were considerably higher than Hg in soil collected from baseline ...

Undoubtedly, land degradation linked to desertification causes a decrease in qualitative and quantitative features of natural resources. This research aimed to assess land desertification by local residents and their role in controlling desertification in Isfahan province, Iran in 2016. The criteria were soil climate, vegetation, erosion, and demography. The indicators of soil texture, stone fr...

abstract one of the importance groundwater resources in kermanshah province is karstic aquifer. this study aimed to investigate the role of development of karstic aquifer in karst springs hydrological properties have been conducted. the studies areas are two karst aquifers include the bistoon-parau and patagh mountain in kermanshah province. in the bistoon-parau region we used of bistoon, berke...

A study was performed to determine groundwater fluoride concentration of Posht-e-Kooh-eDashtestan area located in southern Iran. Groundwater samples were collected from 26 wells, 4 springs, during dry and wet seasons. Fluoride concentration was determined in the water samples using SPADNS method. The results showed that fluoride concentrations are above the World Health Organization (WHO) maxim...

This study evaluates the movement of a frame built on soft soil under seismic excitation taking into account soil-structure interaction. First, was evaluated using finite element method, then, by substructure method which modelled springs and dampers in linear nonlinear study. Rheological models were determined impedance functions, calculated numerical program CONAN. These dynamic impedances ar...

Structural engineers commonly design superstructures as fixed at the base and transmit reactions to infrastructure in order foundation system estimate displacement of soil while disregarding change seismic response that this induces. In article, was transformed into equivalent springs, linear range compared quantified, obtaining results such increased periods, amounts steel reinforcement beams ...