Information systems for geomechanical monitoring in underground structures

Results of the development of a monitoring system for underground structures, which makes it possible to unite and utilize data bases intended for various purposes (geographic, geologic, ecologic), and also results of numerical modeling of the interaction between a structure and rock mass, and data derived from field measurements within the framework of the design of the geographic information system (GIS), are cited for a specific entity. Utilizing the GIS, fixing of the structure in space will make it possible to assess more graphically and informatively the condition of the structure, and the degree of its safety, as well as the influence that it exerts on the adjacent setting and surrounding geologic medium during its construction and service. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 2–5, November–December, 2008.     

Kinetics of the Initial Stage of Crystallization at a Spatially Inhomogeneous Temperature Distribution

The initial stage of crystallization in a glass whose composition is close to the Na₂O · 2CaO · 3SiO₂stoichiometry is experimentally and theoretically investigated under spatially inhomogeneous temperature conditions. It is shown that the crystallization of this glass in an inhomogeneous temperature field is described by the nonlinear thermal conductivity equation similar to the equation accounting for the propagation of a burning front.     

Acidic urine pH is associated with elevated levels of free urinary benzidine and N-acetylbenzidine and urothelial cell DNA adducts in exposed workers

We evaluated the influence of urine pH on the proportion of urinary benzidine (BZ) and N-acetylbenzidine present in the free, unconjugated state and on exfoliated urothelial cell DNA adduct levels in 32 workers exposed to BZ in India. Postworkshift urine pH was inversely correlated with the proportions of BZ (r = -0.78; P < 0.0001) and N-acetylbenzidine (r = -0.67; P < 0.0001) present as free compounds. Furthermore, the average of each subject's pre- and postworkshift urine pH was negatively associated with the predominant urothelial DNA adduct (P = 0.0037, adjusted for urinary BZ and metabolites), which has been shown to cochromatograph with a N-(3'-phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine adduct standard. Controlling for internal dose, individuals with urine pH < 6 had 10-fold higher DNA adduct levels compared to subjects with urine pH > or = 7. As reported previously, polymorphisms in NAT1, NAT2, and GSTM1 had no impact on DNA adduct levels. This is the first study to demonstrate that urine pH has a strong influence on the presence of free urinary aromatic amine compounds and on urothelial cell DNA adduct levels in exposed humans. Because there is evidence that acidic urine has a similar influence on aromatic amines derived from cigarette smoke, urine pH, which is influenced by diet, may be an important susceptibility factor for bladder cancer caused by tobacco in the general population.     

Magnetic properties and time-temperature stability of properties of on iron-and cobalt-based amorphous and nanocrystalline alloys with a destabilized domain structure

Magnetic properties of amorphous and nanocrystalline alloys with a saturation magnetostriction close to zero and a destabilized magnetic domain structure have been studied. A change in the magnetic characteristics has been investigated after two treatments leading to a destabilization of the domain structure: magnetic annealing in a high-frequency magnetic field of 80 kHz and quenching in water. It has been shown that the destabilization by both the first and the second methods markedly improves magnetic properties of amorphous alloys. Nevertheless, upon quenching of amorphous alloys a time-temperature instability of the magnetic properties has been observed. The quenching in water of the nanocrystalline alloys under study results in a deterioration of the magnetic properties.