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Monday, 27 September 2010 16:52

1. IMPLEMENTATION OF MULTI-OPTIONAL MODEL FOR REGULATING TARIFFS ON ELECTRIC POWER UNDER THE CONDITIONS OF INDEFINITE PARAMETERS

D. CHOMAKHIDZE, T. TSABADZE, S. BARATASHVILI, D. BERIKASHVILI
(Georgia)

The article was prepared with the financial support of Georgian National Scientific Fund (Grant GNSF/ST08/7-475).
Any ideas expressed in this publication belong to the authors only and may not reflect the approaches of Georgian National Scientific Fund.



2. PULSE CONTROL OF SPEED OF POWERFUL SYNCHRONOUS ELECTRIC DRIVES OF POWER FACILITIES

JAN DAVIDYAN
(Armenia)

The new way of pulse start-up and speed control of the synchronous electric motors, realised by means of a supply stator windings by current impulses directly from a network through thiristor the switchboard is presented. Current impulses are synchronised with position of a rotor and regulated on a phase and on width. The way of pulse control provides smooth operated start-up of the engine at a supply directly from a network of an alternating current without a car and network overload.

Masso-dimensions and cost of the equipment of pulse control several times it is less, than known devices.
The specified way of pulse control opens a new direction in the theory and practice of operated cars of an alternating current.



3. RAPID METHOD OF ESTIMATING LOAD DEVELOPED BY PROGRESSIVE WAVE ON SMALL BARRIER LOCATED ON SEA SHELF

T. GVELESIANI
(Georgia)

Rapid method for estimating hydrodynamic (wave) load on a barrier is worked out. The barrier has rectangular cross-section shape, and a smaller sizes. The construction is fixed to the basin (sea shelf) bottom.

Prompt estimation of both the wave relative length and velocity and acceleration of water particles within the construction shaft as a result of which inertial and speed wave loads as well as maximum load value are specified are conducted under approximating formulas earlier obtained by the author.

Results obtained under both the above estimation and according to the construction norms and regulations show their reasonable compliance.



4. DYNAMIC ACTION OF IMPULSE WAVES ON A FRONT FACE OF A WAVE DAMPENER

T. GVELESIANI
(Georgia)

Based on a linear theory about the potential wave motion of water, the author earlier obtained an analytic dependance according to which the entire process of the wave interaction with a front face of a hydraulic structure and partially with a wave dampener located by the water surface on a sea shelf or on a bank of the basin which is fixed to the bottom by the cables.

According to the proposed model, as a result of an impulse action of spring (schematizing strong gust) the wave having a complicated shape is generated. An interaction of the wave with the structure will be described by a dynamic wave load varying in time as a result of both the wave setup on the structure and the return from it.



5. ENVIRONMENTAL ESTIMATION ASPECTS OF WOOD FUEL CONSUMPTION

T.KANDELAKI
(Georgia)

Specific effects caused by forest cutting with stable methods and biomass production for fuel usage purposes are reviewed. It is noted, that under the world’s experience, an impact on the forest ecosystem caused by the conduct of these actions in accordance with the established regulations is much less than the important changes for instance caused by intensive (total) cutting of the forest. The following particular environmental issues are discussed: reduction of productivity and risk of long-term production losses, soil biology, an influence of soil temperature and humidity, flora and fauna, seed rescue and early development considering the effect of organic substances, atmosphere (air) emission, ash processing, results of wood fuel preparation, reprocessing, maintenance and transportation activities and other environmental aspects such as mercury formation, carbon dioxide problems, air pollution as a result of wood preparation and transportation; leakage of oil, chemicals and other substances, danger of fire and other dangers. The research results run in Georgia, Scandinavian countries and Canada are basically used in the article.




6. POTENTIAL OF USING SOLAR ENERGY FOR HOT WATER SUPPLY OF GEORGIAN POPULATION. DIAGRAMS AND CLASSIFICATION OF CONTEMPORARY HELIO SYSTEMS

T. MIKIASHVILI, T. JISHKARIANI, G. ARABIDZE, O. KIGURADZE, B. CHKHAIDZE, R. KANDELAKI
(Georgia)

Results of systematization of diagrams of contemporary thermal (technologic) helio systems, classification of helio systems and comparative characteristics are provided. Power consumptions necessary for hot water supply of Georgian household sector and efficiency of using helio systems for these purposes are evaluated: structure of power consumed by Georgian population for hot water supply and ecological figures of its transformation obtained under experts evaluations based on particular assumptions are shown; savings achievable in the household sector by replacing the existing potentialities of the hot water supply by the solar energy are evaluated and investment effectiveness of the helio systems in case of such replacement are analyzed; prices of water heating helio systems at local and world markets are given. Simplified method for evaluating the space of solar collector absorption surface and hot water tank capacity – the main elements of helio equipment which are required for one average statistic (four member) family in Georgia is proposed.



7. DIGITAL MODELING OF NON-FULL PHASE AND ASYMMETRICAL OPERATING CONDITIONS OF SUBMERSIBLE MOTORS

MUSTAFAYEV R.I., SAIDOV R.A.
(Azerbaijan)

For study of open-phase and asymmetrical operating conditions of submersible motors the digital mathematical model of electric motors have been designed, where machine’s equations have been recorded in fixed three-phase coordinate system in suitable for personal computer form.



8. OPERATION MODES OF WIND POWER PLANTS WITH ASYNCHRONOUS GENERATORS UNDER VARIABLE–FREQUENCY CONTROL

MUSTAFAYEV R.I., HASSANOVA L.H.
(Azerbaijan)

Mathematical model (model of state) is presented and different operation models of WPPs, containing asynchronous generators, frequency-controlled both from stator side and from rotor side have been studied on this model. Analytical calculation method has been offered, and its comparison with presented mathematical model has been carried out.



9. RESEARCH OF NONSTATIONARY LAMINAR PLANE-PARALLEL PRESSURE FLOW

A.SARUKHANYAN, A.MANUKYAN
(Armenia)

Nonstationary flat-parallel pressure flow of viscous liquid under arbitrary initial and boundary conditions are reviewed.

Regularities of instantaneous speed distribution on the effective cross-section for a general case when initial speed distribution and pressure difference are given in form of arbitrary function are obtained. The obtained regularities of the instantaneous speeds allow to calculate momentum and kinetic energy factors, power losses in the unbalanced flow, determine the regularity of the profile speed variation (deformation) in time, obtain the character of change of momentum β and kinetic energy factors.



10. PARAMETERS OF CURRENT’S KOHERENTUM

NODAR TAVARTKILADZE, GIA TAVARTKILADZE
(Georgia)

This book is intended for scientific and engineering technical workers who are specialized in the sphere of hydraulic engineering, hydro energy,

hydro melioration and also for the postgraduate students and masters of corresponding specialties for deep studying of hydro engineering course.
For the first time in the sphere of hydraulic were accepted by the authors the radius of inertia in torsion instead of hydraulic radius, which takes into

account the secondary current’s arising into the not round conduits and in the open channels (inside the movement of liquid).




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