E ISSN 1987 - 8257

RESEARCH ARTICLES Print E-mail
Friday, 16 October 2009 19:41
1. About Oxygen Enrichment of Single Zones of Mediterranean Type Seas

J.Kilasonia

Ecologic situation of the Black Sea and Baltic Sea, in particular deterioration of oxygen conditions in these seas and main reasons causing these events, is reviewed. Engineering plan improved by author for oxygen enrichment of separate sea zones using the energy of sea wave is suggested. Application of dependence of wave theory in shallow water for further specification of the results is assumed for designing special structures anticipated for these purposes. It is noted, that these structures should have various dimensions and basically be oriented on the waves the exceedance probability of which is enough for oxygen enrichment of sea layers. For the Black Sea, an idea of oxygen enrichment of upper sea layers in combination with the structures designed for power engineering is suggested.



2. HYDRODYNAMIC ANALYSIS OF THE STARTING CONDITIONS OF THE MAIN PIPELINE

D.Namgaladze

In the article below hydrodynamic analysis of a starting mode of the main pipeline in the presence of a valve on its end changing a linear law of flow, is presented.

The analytical decision by which it is possible to define pressure and speed in any section of
the pipeline at the required moment of time is received.



3. Risk Factors Relating to Investments in Construction of Hydro Power Stations Caused by Probabilistic Character of River Flow.

n.kodua, A. Akhvlediani, V. Sharikadze

Funds invested in the construction of hydro power station are recovered by the sources obtained from the sales of power supplied to the consumers with an appropriate profit. Since the amount of the annual flow changes, it is accepted to run annual estimations according to average long-term consumptions calculated using available hydrologic series, however it is obvious, that the river consumptions observed during operation will not repeat neither in order nor in amount and this will be reflected in revenues as well. Such circumstances put the recovery of the invested funds under risk. An approach avoiding such risks and presented in this article is the following: an adequate statistical model should be prepared according to the hydrologic series with which artificial hydrologic series of the desired length will be generated with Monte-Carlo method.

Average long-term consumptions will be estimated for each series and an average long-term generated power will be calculated using them which from their side will be used for drafting probabilistic distribution bar chart and its approximated distribution curve. 90% reliability generation value and respective tariff will be estimated using this curve.



4. Design and Analysis of Semi-Conductor Transformer System of Traction Sub-Station with Computer Simulation of Transient Processes.

G.Kokhreidze, D.Laoshvili, D.Kokhreidze, I.Kurashvili, L.Indjia

Description of design of semi-conductor transformer system of the traction sub-station, is presented. The principal electrical circuit for the transformer of the traction sub-station prepared according to the circuit “two reverse stars with diphase paralleling reactors” with dc pulse control traction engine is composed.

Mathematical and computer simulation method of non-switching and switching processes of the transformer system subject to traction load parameters, is developed. Flowchartsfor the formation of resultant winding current, phase current instantaneous values for primary and secondary windings of traction transformer, load current and paralleling reactor current in time function both in non-switching and switching intervals, are composed.



5. Prompt Methods for Estimating Principal Parameters of orced Progressive Wave

T.gvelesiani

Mathematical model of forced wave generated within semirestricted horizontal layer of liquid in harmonic variation of wave maker in form of progressive wave is reviewed. Transcendent type variance equation particularly establishes relation between such parameters as vibration frequency of the wave maker and length of the progressive wave. Resolution of the variance equation is achieved by iteration method, in particular on the basis of computer plotting.

Simpler method to determine the roots of the variance equation is suggested. Approximation formula obtained by author for identifying the progressive wave elevation is suggested. An error of the wave parameter estimation results between suggested, approximate and accurate methods is less than 2%.

6. ON CRITERIA OF FORMATION OF HYDRAULIC JUMPS AND ROLLING WAVES

SH.GAGOSHIDZE

Propagation of long waves on stationary flows of arbitrary depth is considered in one-dimensional case. An approach to linearization of a system of basic equations is discussed. Differential equation is derived for long wave oscillations with dispersion. Using this equation, the criteria by which the waves are blocked and destroyed on counter-flows and discontinuous long waves are formed on co-current flows of constant depth are obtained. New relation for calculating conjugate depths, which, as opposed to widely used bakhmetiev’s relation, is equally applicable both to “a perfect jump” and “a wave jump”, is derived.




7. NEW PRESTRESSED REINFORCED CONCRETE STRUCTURES WITH THE SURFACE OF HYPERBOLOID OF THE SHEET


А.Kubaneishvil

New constructions of the prestressed reinforced concerete for power complexes, in particular, chimney, high voltage bearings, arch dam, water conduit chute with the surfaces delineated with the hyperboloid of one sheet, are considered. Linearity formed by this surface is utilised for the orientation of the reinforcement along them by stressing of which volumetrically reduced constructions with increased rigidity and crack resistance are obtained.
 



8.  ANALYSIS OF THE RESULTS OF THE ELECTRODYNAMIC MODELLING OF THE ELECTRIC SYSTEMS IN RESEARCH OF THE DYNAMIC STABILITY


A.Kuliyev

Reports results of numerous experiments performed by Moscow Power Institute together with Électricité de France. Considers automation of test data capture and processing. A statistical analysis is made to find regularities in the probability distributions of the results. Quantitative relations are found and related to system duty. The results of both organisations largely coincide in assessment of accuracy.



9. About Some Issues on Researching Exploited Arch Dams


A.Chrelashvil

Problematic issues relating to the breakdown occurred as a result of the effect of abnormal events within the functioning arch dams are studied. At author’s view, it is necessary to firstly identify real reason causing significant changes in normal functioning of such arch dams based on scientific research. For this purposes, based on field observations and theoretical analysis of possible reasons causing the abnormal events, it is first of all required to take any of the factors that could be considered as possible reason causing such changes as a provisional sought value. The author considers, that the reasons causing the change of mode of deformation of the body of Enguri arch dam particularly is the change of modulus of deformation values of its base. This is associated with significantly increased seepage in the base of this premise. Method of merging of fictitious orthotropic systems should be used to solve this problem.



10.  About Estimation of Energy Losses of Viscous Liquid In Cylindrical Ring Pipe

A.Sarukhanian

Motion of viscous liquid in cylindrical ring pipe is reviewed. Law of velocity change over the effective cross-section is specified in laminar flow, where tangential stresses are determined by Newton’s formula. Constant integrations are obtained from accepted boundary conditions. Average flow velocity in the cylindrical pipe is obtained based on estimation data, and maximum velocity values – by using the equations of velocity distribution over the effective cross-section. Charts of the velocity changes and tangential stresses over the effective cross-sections have been drafted for various pipe radius values R1 and R2. Coefficients a and b of the velocity maldistribution over the effective cross-section have been determined and respective charts drafted. Final estimation result – derivation of expression for overall energy losses in the ring pipe. The respective charts are drafted based on such results.



11. THE EFFECTS OF HABITAT RESTORATION and HYDROELECTRİC DAMS ON THE SALMON (SALMO TRUTTA LABRAX) POPULATION OF THE SMALL STREAMS IN THE EASTERN BLACK SEA REGION OF TURKEY

K.SEYHAN, E.MAZLUM, D.TURAN, S.ENGİN, G.DALGIÇ, H.İMAMOĞLU

Salmon is called the king of the fishes in the world. It's been told that the scientific name is given by Julius Caesar, who heard something about a fish which had the ability of jumping up rapids. That's why he named the fish Salmo (the jumper). Black Sea Trout, Salmo trutto labrax are born in fresh water; in small streams, and then migrate out into the Black Sea to feed. During their migration into the streams to spawn they are subject to sport by anglers, fisherman and man-made hindrances as well as construction of hydroelectric power generation and feasibility studies conducted in the Eastern Black Sea region of Turkey.

A classic example of the mass destruction of a population of salmon recently caused by man-made hindrances occurred on the Çağlayan and Fırtına Streams in the Eastern Black Sea, Turkey where no detailed information is available in most cases.

In this report, therefore, a detail account is to be given on the life history of Salmo trutto labrax in the Eastern Black Sea and problems that labrax faced and recommendations to overcome will be highlighted.

 



12. BIOGENIC ISOPRENE: FROM SCIENtific discoVery up to pRACTICAL APPLICATION


G.Sanadze

Brief historical review of research performance regarding isoprene effect (IE) is given in this paper: special role of light as a source of energy and CO2 as a source of carbon, establishing energoplastic stream as a whole which, penetrating green photosynthetic cell, is underlined here. The existing data allow us to review IE as exhibition of excretory function of leaf. We tried to describe IE in the light of concept of thermodynamics of nonequilibrium processes. It is shown that the cell represents a dissipative structure. Up-to-date information of Monson and his colleagues regarding existence of double carboxylation in a photobiosynthesing cell leading to the formation of dimethyllilpyrophosphate - isoprene precursor is emphasized in this article. On the whole IE is reviewed as a result of regulation of carbon and free energy transformation in chain of photosynthetic reactions under the conditions caused by CO2 deficiency within lighted autotrophic cell and the cell represents the structure permanently dissipating entropy. The article states about the first photobiological reactor for isoprene production in large quantities via transgenic unicellular organisms. The issue on obligate loss of part of free energy by cell is discussed in this article.

 

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