Synthesis of acid-base transformations of 3-aroyl-6-methyl-2-oxopyridines

In hydrolysis of 3-aroyl-6-methyl-2-methoxypyridines, 3-aroyl-6-methyl-2-oxopyridines are formed, which with methyl iodide in an alkaline medium give the corresponding 1-methyl derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1354–1356, October, 1986.     

A very large diversity space of synthetically accessible compounds for use with drug design programs

We have constructed a very large virtual diversity space containing more than 10¹³ chemical compounds. The diversity space is built from about 400 combinatorial libraries, which have been expanded by choosing sizeable collections of suitable R-groups that can be attached to each link point of their scaffolds. These R-group collections have been created by selecting reagents that have drug-like properties from catalogs of available chemicals. As members of known combinatorial libraries, the compounds in the diversity space are in general synthetically accessible and useful as potential drug leads. Hence, the diversity space can be used as a vast source of compounds by a de novo drug design program. For example, we have used such a program to generate inhibitors of HIV integrase enzyme that exhibited activity in the micromolar range.     

Acoustic-Emission Monitoring of the Deformation and Fracture of Metal–Composite Pressure Vessels

This paper presents the results of experimental studies of damage accumulation in a metal–composite pressure vessel by pneumatic strength tests. The deformation and fracture of the composite structure accompanied by matrix cracking and fiber rupture are analyzed. It is shown that the cracks and fractures generate acoustic-emission signals of various types. The results of acoustic-emission monitoring were used to develop a criterion for ranking vessels according to the strength characteristics of the pressure composite shell.     

Propagation of compression waves in bubbly liquid with hydrate formation

The dynamics of planar one-dimensional shock waves applied to the available experimental data for the water-Freon system is studied on the basis of the theoretical model of the bubbly liquid refined with regard for a possible hydrate formation. A scheme is proposed for considering the fragmentation of bubbles in the shock wave, which is one of the main factors of the intensification of the hydrate formation process with the growth of the shock wave amplitude.     

Hydrodynamic Aspects of Confluence of Rivers with Different Water Densities

Journal of Applied Mechanics and Technical Physics - Confluences of rivers are characterized by highly complex intrabasin processes. The arising hydrodynamic aspects of river confluences have...     

Numerical modeling of liquid-waste infiltration from storage facilities into surrounding groundwater and surface-water bodies

This study focuses on the infiltration of saturated brine from liquid-waste storage facilities into the surrounding groundwater and surface-water bodies. The storage facilities are situated at the Verkhnekamsk Potassium and Magnesium Salt Deposit (Perm krai, Russian Federation); they store highly mineralized brine of potassium, sodium, and magnesium chlorides. An analytical solution of a one-dimensional equation of contaminant transport by a homogeneous steady-state groundwater flow is used to estimate the time it takes the contaminant to travel from the storage facilities to the nearest surface water body, as well as to evaluate the formation time of a stationary concentration profile, with contaminant adsorption in the porous matrix either neglected or taken into account. The contaminant concentration at the point of brine entry into the surface water body is calculated. The ANSYS Fluent software package is used for direct 3D simulation of brine infiltration into the surrounding medium. The simulation results revealed different stages of contaminant propagation in the porous medium. The contaminant was found to spread over a wide area with an almost uniform high brine concentration close to the saturation value. The contaminant reaches the nearest riverbed approximately 20 days after the start of infiltration. The estimates of the time required for the contaminant front to reach the surface water body obtained by three-dimensional simulation agree with the analytical estimates derived from a one-dimensional model. The proposed system of physical models adequately describes the hydrodynamic processes accompanying the operation of large storage facilities and can be used to predict contaminant-front propagation in the groundwater near storage facilities.     

Chemical Oxidation of LiFePO<Subscript>4</Subscript> in Aqueous Medium as a Method for Studying Kinetics of Delithiation

The kinetics of LiFePO₄ oxidation by hydrogen peroxide in aqueous alkaline medium is studied with the use of potentiometric determination of lithium concentration in solution during delithiation. It is demonstrated that the lithium transfer through the reaction-product layer is controlled by diffusion. The activation energy and the diffusion coefficient of the species transferred in the solid phase during the chemical reaction of oxidative delithiation are determined and the parameters of this processes are analyzed.     

Statistical fracture modeling of weld joint for nuclear reactor components

Probabilistic safety and risk assessment of nuclear reactor equipment are referred to as integrated safety assessment which is implemented by the application of probabilistic fracture mechanics (PFM). Such a study is based on statistical simulation of weld damages under dynamic condition. Because of damage accumulation in welded nuclear reactor components under dynamic load, the need for evaluating the risk of fracture is apparent. This work considers the statistical simulation of dynamic damage of weld joint by fracture. Considered in the analysis are weld defects, damage accumulation, crack initiation and crack growth.