Energy Characteristics Of Systems Research Articles

INVESTIGATION OF THE OPERATION MODES OF THE BELT-ROPE CONVEYOR ELECTROMECHANICAL SYSTEM WITH VECTOR-CONTROLLED INDUCTION ELECTRIC MOTORS

Continuous transport systems are the most promising type of movement of loose and artificial materials, have high productivity, technical and economic indicators and are widely used in world practice as main conveyors for the coal and mining industry. A special place in continuous transport is occupied by belt-rope conveyors, which are capable of transporting cargo over a distance of more than 30 km in one stop. As a rule, these main conveyors do not provide for the adjustment of movement parameters, the start is carried out using soft start systems. At the same time, such systems have high requirements for the parameters of dynamic modes of operation, the accuracy of working out the given movement program and the level of energy efficiency. The paper proposes a modern electric drive system using vector-controlled induction electric motors. The structure of the electromechanical system is given. A mathematical model of the electromechanical system was built using known methods. As part of the “MATLAB” Simulink application program package, a model for the investigation of dynamic modes of conveyor operation was obtained. On a specific example, a research of dynamic and static modes of conveyor operation with static load and the speed of movement variations of the traction element was carried out. Studies of the accuracy of working out the given law of motion showed that the maximum dynamic error in terms of speed and current is worked out in a time of up to 0.06 s. The maximum level of its amplitude does not exceed 0.33% of the constant speed of movement, which does not cause oscillatory processes in the conveyor and ensures stable operation of the electromechanical system. Investigation of the electromechanical system energy characteristics was conducted. Losses of active power do not exceed 12.5% of the consumed in the entire range of variation of the static load and speed of the traction element. Recommendations for the use of electromechanical systems with vector-controlled induction electric motors in belt-rope conveyors have been formulated.

Technology elements of behavioral energy testing of distributedinformation systems

Early testing of the reliability of functioning, performed before the occurrence of critical emergency situations, plays an important role in the theory and practice of monitoring and diagnosing various technical systems, including computer distributed information systems. Many checking and diagnostic methods directly or indirectly use the energy characteristics of systems, that are directly related to the work they execute, that is, their performance. The proposed elements of the technology of behavioral energy-consumptiontesting are based on the corresponding models and methods, supplemented by the registration and analysis of inertial temperature and operational volt/ampere char-acteristics of the test behavior of systems, at the model level represented by extendedenergy-consumptionPetri nets. The elements of behav-ioral testing technology,proposed in thiswork,are distinguished by an additional set of calculated and empirical boundary temperature and volt/ampere characteristics of both systems and their components. These characteristics represent states/vertexes,positions/transitions,frag-ments and scenarios of operation,that are critical in terms of energy consumption, which gives grounds for their monitoring. A feature of these elements of the technology is also the possibility of determining and using natural identifying properties of energy characteristics in behavioral testing, which allows them to be used in check and recognition experiments for the reliability of functioning, both independently and in conjunction with behavioral analysis. The use of additional analysis of energy consumption by temperature and volt/ampere character-istics,as part of complex testing technologies and automatic systems of technical diagnostic,based on them,makes it possible to increase the efficiency, completeness and flexibility of behavioral online and offline testing for computer distributed information systems.

Quantum chemical calculations for the hydration of model silica modified by aliphatic amines

Various basis sets and methods for quantum-chemical calculations are analyzed, and the effect of the number of diffusion and polarization functions on geometry and energy characteristics of systems that simulate the surface of silica modified by aliphatic amines is studied. The contribution from correlation effects and the superposition error of the basis set to the values of the energy characteristics of the hydration of model objects is evaluated. A section of an aminosilica surface was hydrated in simulation. Conclusions as to the existence of arched structures on the surface of aminosilica that include amino and silanol groups are confirmed.

Transient analysis of multi-state dcdc converters using system energy characteristics

The study of multi-state dcdc power conversion techniques is restricted by the complicated inner switching behaviors. This paper presents a general and unified transient analysis for various sorts ...

Transient analysis of multi‐state dc–dc converters using system energy characteristics

AbstractThe study of multi‐state dc–dc power conversion techniques is restricted by the complicated inner switching behaviors. This paper presents a general and unified transient analysis for various sorts of multi‐state dc–dc converters from a viewpoint of their system energy characteristics. With the applications to the boost converters, the proposed analytical method has indicated its advantages of high convenience and practicability to the multi‐state converters. The generalized concepts of system energy parameters of dc–dc converters are introduced and applied to the transient analysis. Consequently, the expressions of system model parameters of multi‐state dc–dc converters are deduced. The new 2nd order transfer functions are obtained to describe the large‐ and small‐signal mathematical models accurately. The model simulation and experimental results are provided to support the theoretical analysis. Copyright © 2007 John Wiley & Sons, Ltd.

Theoretical studies of the conformations and interaction properties of neutral lipid molecules: glycerylmonooleate

A theoretical study of the conformation and interaction properties ofglycerylmonooleate molecules was carried out as a preliminary step towards understanding their organization into layers. The evolution of the structural and energy characteristics of systems comprising one to seven molecules is described, putting into evidence the respective contributions of the polar heads and hydrocarbon chains. The dependence of the interaction energies on the geometry of the molecular packing shows the flexible and polymorphic properties. A disposition in layer was found, where the packing of the heads controlled by a network of hydrogen bonds is easily accommodated with the packing of the chains, due to the easy rotations around the bonds linking heads and chains.

Energy of the adsorption of gases and vapors on microporous adsorbents

1. A calorimeter of the Tian-Calvet type was constructed. The measuring constants and technical operating characteristics of the instrument in certain respects are better than that of the well-known Calvet precision instrument. 2. The new method was used to measure endothermic processes (heats of desorption) by compensating for them with an exothermic Peltier effect. The heats of desorption are in good agreement with the heats of adsorption. 3. The adsorption isotherm of propane on NaX is strictly linear all the way up to 20% filling of the adsorption space (the Henry region). In this region, in the formal calculation the adsorption is less than or, in the limit, equal to one propane molecule on the average per large cavity of the zeolite, while the differential heats of adsorption are practically constant. When the number of adsorbed molecules increases on the average for four per cavity, a linear increase in the differential heat of adsorption is observed. The corresponding contribution of the fifth adsorbed molecule to the differential heat of adsorption is practically twice as great as for each of the preceding molecules. 4. On the whole, the calorimetric measurements indicated that final energy characteristics of systems of microporous adsorbents can be obtained with the instrument designed; these characteristics had heretofore been inaccessible either to indirect methods of calculation or to other high-class calorimeters.