Boiling crisis under liquid flow in channels with a high mass flowrate and subcooling

A physical model of liquid boiling crisis in channels with smooth walls at high subcooling and high mass flowrate is presented. The condition of the crisis incipience is stated. The calculation correlation for critical heat flowrate q _cr in channels is given, which enables to analyze the effect of the channel diameter, subcooling, and mass flowrate on q _cr.     

Characterization of the Organic Matter of Humic Acids by Pyrolytic Gas Chromatography–Mass Spectrometry

The results of the pyrolytic analysis of products of the organic matter of Sphagnum fuscum, fuscum peat, and humic acids separated from peat with the use of pyrolysis–chromatography–mass spectrometry in the Rock-Eval version are presented. It was shown that Sphagnum fuscum and peat differed only slightly in the degrees of chemical transformation. Benzene, phenol, and their alkyl-substituted homologues predominated in the thermal desorption products of humic acids upon pyrolysis to 400°C. Acetic acid, monohydric phenols, syringol, and guaiacol, which are the basic compounds in the high-temperature fraction, were formed on the pyrolysis humic acids to 700°C from the carbohydrate, phenylpropionic, and guaiacylpropane structural fragments.     

Extraction of Pt(IV) and Pd(II) from Hydrochloric Acid Solutions Using Polypropylene Glycol 425

Theoretical Foundations of Chemical Engineering - An environmentally friendly extraction system based on polypropylene glycol 425 and sodium chloride for the extraction of Pt(IV) and Pd(II) from...     

Liquid–Liquid Equilibrium in an Extraction System Based on Polyvinylpyrrolidone-3500 and Sodium Nitrate

Theoretical Foundations of Chemical Engineering - Liquid–liquid phase equilibrium for a new extraction system based on polyvinylpyrrolidone-3500 and sodium nitrate at 298.15, 313.15, and...     

Algorithms for accelerated solution of systems of linear equations with Toeplitz matrices

The possibilities of the application of a linear distortion compensation algorithm in solving the systems of linear algebraic equations with band matrices are considered. The relationships required for the step-by-step solution procedure are derived, and the conditions of their correct application are determined.     

Unloading angular momentum for inertial actuators of a spacecraft in the pitch channel

The problem of gravitational unloading of the angular momentum of inertial actuators of a spacecraft in the pitch channel for circular and elliptic orbits is considered using the band theory of modal control. Control laws for gravitational unloading and stabilization of a given spacecraft position unambiguously determined by the object parameters and given coefficients of characteristic equation are obtained.     

Limit theorems for queueing systems with doubly stochastic poisson arrivals (Heavy traffic conditions)

We consider a single-server queueing system with a doubly stochastic Poisson arrival flow under heavy traffic conditions. We prove the convergence of the limiting stationary or periodic distribution to the exponential distribution. In a scheme of series, we consider the C-convergence of the waiting time process to a diffusion process with constant coefficients and reflection at the zero boundary. Examples of computation of the diffusion coefficient in terms of characteristics of the arrival flow and service time are given.     

Synthesis of stabilizing spacecraft control based on generalized Ackermann’s formula

Problem of modal synthesis of controllers and observers using the generalized Ackermann’s formula is solved for a spacecraft as a complex dynamic system with high interconnections. All possible controller matrices (the whole set of controllers) are obtained for solution of the problem of stabilization of orbital orientation of the spacecraft in inseparable channels of bank and yaw angles.     

Transformation of a mealy finite-state machine into a moore finite-state machine by splitting internal states

The problem of transformation of a Mealy finite-state machine (FSM) into an equivalent Moore FSM is considered. This problem often arises in the practice of engineering design, when one needs to avoid direct dependence of the output values on variations in the input values. The proposed approach uses the operation of splitting of internal states of an FSM and represents the machine as a list of transitions. Experiment results have shown that transformation of Mealy FSM into Moore FSM increases the number of internal states, on the average, by a factor of 1.96 and increases the number of transitions by a factor of 2.05; the cost of realization of Moore FSM using an industrial software package is approximately twice as great as the corresponding cost for a Mealy machine. The up-to-date tendencies of development of minimization methods and Moore FSM synthesis are described.