Concentration convection in liquid mixtures in closed spaces

Concentration fields of binary liquidq are considered in the paper aiming at the investigation of the influence of the free convection on concentration in liquid mixtures; the development of plants and methodologies for the experiment holding of the convection detection under microgravitation. As a result the thermodiffusion convection of solutions in an inclined rectangular space and a horizontal cylindrical layer has been investinated as well as particular features of the mixture separation. The interferometer, cell and methodologies for experiments of the detection and investigation of convective effects under microgravitation conditions have been develped. New equipment and methodologies for the convection investigation in liquid mixtures are being used. The paper results may find their field of application in mechanics liquid, gas and plasma, thermal physicsAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Mimimizing the cost of using tractors at agricultural operations

The paper shows the economic efficiency of the optimal use of technology in crop production. A totally new model has been developed ,that allows planning the operation of each tractor individually, as well as an integer programming method with Boolean variables based on the formation of a lexicographic sequence. The paper shows the calculation according to the optimization criterion of the minimum duration of the work. The developed method of integer programming is original because it allows to solve problems typical of agricultural planning. For this, the authors derived a formula for the formation of any member of the lexicographic sequence and developed the AgroMaster + computer program, which also carries out the search for the optimal solution using the method of truncated exhaustive search. Due to optimal planning, the total duration of agricultural operations is reduced by 1.7 times compared to their actual duration. The cost of additional products received per 1 moto-hour is 7.3 dollars. The testing the results of studies in one of the farms of the Republic of Bashkortostan showed the possibility of practical application of the above developments for optimal planning of tractors in any agricultural enterprises

Optimum Planning Use of Equipment in Agriculture

Purpose: to reduce operating costs when performing agricultural mechanized work. Design/methodology/approach: The development of the desired economic and mathematical model of the optimal MTA distribution by type of work is based on the above condition it is necessary to plan the work of not tractor brands indicating their number, but each tractor individually. Findings: It is known that the availability of equipment varies during the season, so it was studied in dynamics. In this regard, to solve this problem, neural-network simulation was first used. As a result of the search, a network of the type of radial basis function was obtained that best describes these dependencies Research limitations/implications: the authors developed a fundamentally new mathematical model for optimizing the use of technology, which, unlike existing ones, allows to: • plan the operation of each tractor individually; • designate the so-called “mandatory tractors”, that is, those that the user, at his discretion, would like to assign to a particular operation or vice versa, would like the tractor operator not to work on this operation. Originality/value: Thus, the scientific novelty of the work performed are: • a technique for operational planning of work and increasing the efficiency of using the MTA, taking into account the technical condition of the tractors, the specific conditions for their functioning and the work experience of the machine operator. • a mathematical model for solving the problem of the optimal distribution of MTA by type of work and the mathematical apparatus for its implementation; • a technique for adjusting the performance of the MTA, taking into account the experience of the tractor driver, the service life and technical readiness of the tractorPeer Reviewe

Adaptive Micromixer Based on the Solutocapillary Marangoni Effect in a Continuous-Flow Microreactor

Continuous-flow microreactors are an important development in chemical engineering technology, since pharmaceutical production needs flexibility in reconfiguring the synthesis system rather than large volumes of product yield. Microreactors of this type have a special vessel, in which the convective vortices are organized to mix the reagents to increase the product output. We propose a new type of micromixer based on the intensive relaxation oscillations induced by a fundamental effect discovered recently. The mechanism of these oscillations was found to be a coupling of the solutal Marangoni effect, buoyancy and diffusion. The phenomenon can be observed in the vicinity of an air⁻liquid (or liquid⁻liquid) interface with inhomogeneous concentration of a surface-active solute. Important features of the oscillations are demonstrated experimentally and numerically. The periodicity of the oscillations is a result of the repeated regeneration of the Marangoni driving force. This feature is used in our design of a micromixer with a single air bubble inside the reaction zone. We show that the micromixer does not consume external energy and adapts to the medium state due to feedback. It switches on automatically each time when a concentration inhomogeneity in the reaction zone occurs, and stops mixing when the solution becomes sufficiently uniform