Content of heavy metals in various kinds of loose-leaf tea

The content of heavy metals--lead, cadmium, mercury, arsenicum was studied in 7 kinds of tea. Lead was detected practically in all studied kinds of tea, except for self-drinking long-lenved tea Sri-Lanka, cadmium was detected in Chinese Green coarse-grained tea, arsenicum was detected in all kinds of tea. However heavy metals content in all studied kinds of tea doesn't exceed their maximum allowable concentration.     

Anisotropy Effect of the Mechanical Metal Properties on the Assessment of the Load-Carrying Ability of the Launch Vehicle Oxidant Tank

Strength of Materials - The paper presents the results of the calculated estimate of the critical pressure level in the oxidant tank of the launch vehicle using generalized diagrams of...     

Modified Elastic Solution Processes and Interchangeable Elasticity Parameters in the Problems of Radiation Creep

Strength of Materials - Methods of elastic solutions and interchangeable elasticity parameters for solving nonlinear boundary value problems of mechanics are considered, making it possible to...     

Analysis of Irradiation Swelling and Irradiation Creep Models with the Stress Effect Account in the Problems of Inelastic Strain Mechanics. Part 2. Correctness Check of Conditions of the Constitutive Equations

Strength of Materials - The results of an analysis of the correctness of constitutive equations of irradiation creep which describe non-isothermal processes of inelastic deformation taking into...     

Computational Evaluation and Analysis of Change in Shape Peculiarities of WWER-1000 Baffle Under Design and Long-Term Operation Conditions

Strength of Materials - The peculiarities of the calculated assessment of the stress-strain state and the shape change of the WWER-1000 reactor core baffle under the design and long-term operation...     

Multi-objective shape optimization of a hydraulic turbine runner using efficiency,strength and weight criteria

An approach for multi-discipline automatic optimization of the hydraulic turbine runner shape is presented. The approach accounts hydraulic efficiency, mechanical strength and the weight of the runner. In order to effectively control the strength and weight of the runner, a new parameterization of the blade thickness function is suggested. Turbine efficiency is evaluated through numerical solution of Reynolds-averaged Navier-Stokes equations, while the finite element method is used to evaluate the von Mises stress in the runner. An objective function, being the weighted sum of maximal stress and the blade volume, is suggested to account for both the strength and weight of the runner. Multi-objective genetic algorithm is used to solve the optimization problem. The suggested approach has been applied to automatic design of a Francis turbine runner. Series of three-objective optimization runs have been carried out. The obtained results clearly indicate that simultaneous account of stress and weight objectives accompanied by thickness variation allows obtaining high efficiency, light and durable turbine runners.