Calculation of the energy J -integral for bodies with notches and cracks

Abstract. The approximate solutions for calculation of the energy J -integral of a body both with a notch and with a crack under elastic-plastic loading have been obtained. The crack is considered as the limit case of a sharp notch. The method is based on stress concentration analysis near a notch/crack tip and the modified Neuber's approach. The HRR-model and the method based on an equation of equilibrium were also employed to calculate the J -integral. The influence of the strain hardening exponent on the J -integral is discussed. New aspects of the two-parameter J * c -fracture criterion for a body with a short crack are studied. A theoretical investigation of the effect of the applied critical stress (or the crack length) on the strain fields ahead of the crack tip has been carried out

Numerical simulation of oil pool boundary evolution

The study of spatial distribution of hydrocarbon resources and forecasting their geographical location is of great importance for the most complete recovery of hydrocarbons from deposits. The present study gives new mathematical results in the theory of stratified fluid flow in a porous medium. This paper analyzes the evolution of oil pool boundary basing on vortex numerical model for movement of the boundary separating fluids of different densities. It presents the investigation of how the location of light fluid regarding the heavier fluid influences on the changes in the boundary between two media in case of various shifting of the well

Laser sounding of instantaneous and mean speed of wind using correlation method

The correlation methods for laser sounding of wind speed are based on mutual processing of lidar signals scattered from several spatially separated volumes at each altitude investigated. The time of atmospheric aerosol transport between the scattering volumes estimated by the position of maximum of the mutual correlation function is the measure of corresponding wind speed. In this case the distance between the scattering volumes (the measuring base), defining the time of aerosol movement through the measuring base also determines the lidar possibilities for measuring the instantaneous (during the time interval of several seconds) or the mean wind speed (some minutes). Based on the experimental investigations performed using two lidars, these possibilites are analyzed

Use of a new breeding methods for creation of breeds with desired properties and traits

In modern crop production (including field, vegetable, fruit and berry, ornamental and even some forest crops), breeds are cultivated. All of them are the products of breeding (the branch of agricultural production). According to various sources, selection currently provides from 25 to 40% of the increase in yield, the rest falls on the share of cultivation technology. There are examples of a more significant contribution of breeding to yield growth. Breeding is available for such changes in the quality of products that are beyond the power of agricultural technology, for example, the color range of flowers of ornamental crops, the composition of oil in oilseeds, improving the baking qualities of flour in wheat, and increasing the content of substances with medicinal properties in medicinal plants

The role of breeding centers and breed testing systems in the development of breeds with a wide potential for use

It shall be noted that the country's food security is impossible without modern breeding and seed production, which fully applies to both open and protected ground. Grain crops, wheat, barley, corn, rice and others, in terms of fodder productive qualities, are always among the most valuable agricultural crops and are the staple food in many countries of the world. The production of advanced agricultural products is carried out through the use of effective methods of genetics, breeding, seed production, diagnostics of pathogens, integrated plant protection products, the latest technologies and others. The tasks of breeding and seed production of agricultural crops are the reproduction of seeds of breeds and the maintenance of their genetic potential in order to preserve the properties and economically valuable traits. High-quality seeds of the best zoned breeds and hybrids are the foundation of the future harvest. Breeds with a wide adaptive potential allow them to be grown in different climatic conditions and to select for the best forms

Criticality in one dimension with inverse square-law potentials

It is demonstrated that the scaled order parameter for ferromagnetic Ising and three-state Potts chains with inverse-square interactions exhibits a universal critical jump, in analogy with the superfluid density in helium films. Renormalization-group arguments are combined with numerical simulations of systems containing up to one million lattice sites to accurately determine the critical properties of these models. In strong contrast with earlier work, compelling quantitative evidence for the Kosterlitz--Thouless-like character of the phase transition is provided.Comment: To appear in Phys. Rev. Let