Volume 1, No. 7 (2001)
Articles
RESEARCHES CONCERNING THE DESIGNING AND THE ACHIEVEMENT ONE MILL OF THE SMALL CAPACITY FOR MILLING CORN
KARAMOUSANTOS DIMITROS 1, BERCEA MIHAI 2, TENU IOAN 3
The milling of the corn for the human consumption requires several operations. For the achievement one the mill for corn of small capacity it has been achieved studies and researches through which it has determinated constructive solutions so that to respect all technological operations of milling process. So, the cleaning of seeds it achieves through a pneumatic separation. For the milling of the grain it can use a roll mill with 3 rollers but for the sifting of the milling produce it can use a cassette with 2 sieves which allows the separation of the bran, the semolina meal and of the powder flour.
STUDIES CONCERNING THE OPTIMISATION OF TRAINING MECHANISMES OF PLANE SIEVES FROM THE COMPONENCE OF THE CLEANING MACHINE FOR SEEDS.
KARAMOUSANTOS DIMITROS 1, NEAGU GABRIELA 2, TENU IOAN 2, BĂLAN OVIDIU 2
Studies achieved took in the consideration die optimization of the mechanism through which it assures the training of working organs of cleaning machines for seeds. The optimization of mechanismes has been achieved through the obtaining the maximum working capacity. It has taken in study, both the general case of the one sifting sieve and real mechanismes for the training such as: crank gear and oscillating crank lever.
THE OPTIMISATION OF SIFTING SIEVES TO THE WHEAT MILL OF THE MIDDLE CAPACITY
TENU IOAN, BERCOVICI CATALIN, KARAMOUSANTOS DIMITROS
For the increasing of the performances to the wheat mill of the middle capacity it has been achieved the studies and research for the optimization of sifting sieves. Results obtained have allowed stating an optim operating and constructive correlation between the milling capacity of the roll mill and the sifting of sieves. For the achievement of these studies it has been achieved an increasing of the operating capacity and the maximizing of the extraction coefficient in the same time.
RESEARCHES CONCERNING THE INCREASING OF THE DOUBLE ROLL MILL PERFORMANCE FOR MILLING OF THE WHEAT
TENU IOAN, BERCOVICI CATALIN, KARAMOUSANTOS DIMITROS
The double roll mill represents for the wheat mill, the conducting machineries which conditions the operating capacity. Therefore, it has been achieved studies and researches for modernization of the double roll mill, in sense of their increasing productivity and for the reduction of the energetically consumptions per the unit of milled produce. At die same time, on die base of results obtained it has redesigned die double roll mill and it has stated constructive solutions which determines die increasing of die liability in die operating.
KINETIC ASPECTS OF REDOX EQUILIBRIUM IN GLASS USED FOR ENVIROMMENT PROTECTION
CĂPĂŢÎNA CAMELIA, CÎRTÎNA DANIELA
It is known that copper oxide introduced in glass batches produced red colour when melted under reducing conditions. However, the production of bright and uniform red colour has been reported to be one of the most difficult of all coloured glasses. The entire problem was investigated and after a detailed study extending over several years, the technique, conditions and batch compositions suitable for producing uniform and bright red colour were developed. A method was established for evidencing the evolution in time of the oxidized/reduced ratio for ions in given melting conditions. In this aim were recorded the electronic spectra, the peak corresponding to the d-d electron transmition being used for Cu + ion concentration estimation. The obtained results are discussed in comparison with existing data. The problem of the glass basicity influence upon the redox equilibrium is approached too.
IMPROVING OH, RESERVOIRS DEVELOPMENT USING ARTIFICIAL NEURAL NETWORKS
MARIAN BADIN, CONSTANTIN POPA
This paper presents a new assessment technique of EOR applicability methods with NN aid based on the existing petroleum industry experience in implementing EOR processes at different reservoir conditions. Assessment of success is based on applicability ranges of the main reservoir characteristics for different EOR methods. The trained NN enabled us fast evaluation of EOR methods applicability.
MECHANICAL FEATURES OF GRAPES - RAW PRODUCT FOR FOOD INDUSTRY
BAISAN IOAN
The paper presents the mechanical features of the main varieties of grapes for wine production as well as some varieties of grapes for consumption produced in Romania. The experimental results concerning the detachment force of the grapes from the pedicles and the crushing force of the grape peel according to the maturation degree, are presented.
NEW MEASURES FOR THE PROTECTION OF THE ENVIRONMENT IN ANIMAL BREEDING
BĂLAN OVIDIU
Conventional agriculture in general and animal breeding particularly may have a negative and long effect on the environment, while struggling for the increase of the production. The environment may be deteriorated by the proliferation of the sources and resources of pollution (chemicals, soil erosion, clearing, dejections). These destructive actions and the environment can be counteracted by man through the knowledge of biological laws of nature. The potential polluting factors could be transformed into factors of protection, improvement and conservation of ecosystem by the use of a non-polluting technology.
VARIATIONS OF A RESONANCE CURVE DUE TO THE ANGULAR POSITION OF AN UNBALANCE AT THE MAJOR CRITICAL SPEED
BIBIRE LUMINIŢA, MARIN M., MARIN C., COBREA CODRIN
In order to find some way to detect a transverse crack due to fatigue in a rotating machine, we have investigated experimentally and theoretically the change in the resonance curve caused by the occurrence of a crack. It is shown that this phenomenon is explained theoretically by combining the characteristics of the unsymmetrical shaft and that of the symmetrical shaft or by considering rotating nonlinear spring characteristics.
RESEARCH CONCERNING ON NON-LINEAR BEARING FORCES
BIBIRE LUMINIŢA, MARIN M., MARIN C., COBREA CODRIN
Advanced rotor-bearing design requires increasingly nonlinear analysis to give a comprehensive view of the effects caused by journal bearings. Journal bearings introduce into the system a nonlinear asymmetry and strong damping. Unstable region predict from linear analysts of the bearing (i.e. using stiffness and damping matrices) are understood as region in which amplitude of vibrations increases with time. The non linear mechanism limits the amplitudes of vibration of unstable rotor bearing systems and forms limit cycles
EXPERIMENTAL INVESTIGATIONS CONCERNING THE INFLUENCE OF THE VIBRATIONS ON THE WEAR OF THE MACHINE - TOOL GUIDING COUPLES MADE IN FERROUS MATERIALS
BRABIE GHEORGHE, CHIRIŢĂ BOGDAN
The wear is one of the most important dangerous processes with small speed which generates the loss of the machine tool accuracy, the decrease of the machine efficiency, the decrease of the resistance to dynamic loads, the increase of the noises, a.s.o. The vibrations which accompany the working processes developed on the machine tool lead not only to the generation of the surfaces with geometric errors or to the decrease of the working productivity, but also to the intensification of the machine components wear. The present paper analyses the influence of the vibrations on the wear process developed in the guiding couple of a plane grinding machine.
CRITERIA AND MODELS OF OPTIMIZATION OF THE MILLING TECHNOLOGIC PROCESSES
BRABIE GHEORGHE
The new developments and requirements in metal machining systems need more and more the optimization of the design of high performance technologic processes and equipment. The present paper discusses and presents some technical solutions, criteria and models used in optimization of metal milling processes.
CONTRIBUTIONS REGARDING THE ESTABLISHMENT OF THE IMPACT THAT THE MINING ACTIVITIES HAS ON THE ECOSYSTEM OF THE CALIMANI AREA - 3. THE INFLUENCE OF THE HARD METALS RESULTING FROM THE CALIMANI MINE WORKING ON THE QUALITY OF THE FOOD PRODUCTS
CIOBANU DOMNICA*, DIŢOIU VALERIA**
This work presents the impact of the hard metals resulting from the mining activities on the quality of the food products and on the health of the population. Hard metals resulting from mining activities are the main cause of some serious ecological lack of poise, but also an important source of pollution of food products. This way, the quantities of cadmium, lead, copper and zinc resulting from the mine working Calimani, surpass the accepted concentrations in the superior layers of the soil on a vast specific spreading area for species. As a result of the soil contamination with hard metals, through the transfer soil - plant - human or soil - plant - animal-human, there is a growth in the concentrations of this metal in the vegetation with direct and indirect obnoxious effects on the population's health.
FROM INSURING QUALITY TO EXCELLENCE
CRISTEA ION, AXINTE CRINA
Nearly one third of undertakings certified by the norms ISO 9000 are tacking part in a race against the clock for the so-called "total quality". This is not a fashion phenomenon but a response to a real need to search a new spur in this moment after the certifying. It's a necessity for the clients, who are more and more demanding, that the undertakings should direct their management towards improving their performance and their products in order to fully satisfy the needs of their customers. One client out of four is inquiring about how their point of view is appreciated and only in 50% of the cases their question is taken into consideration. The work presents a series of modern requirements of the quality systems, some considerations concerning the reviewed norms of ISO 9000 series 2000, some problems related to the cost of non-quality, and the influence of quality for an undoubtedly evolution towards the goals exposed in the title.
NEW DESIGN FOR ROTATING JOINT
FLORESCU DANIELA, FLORESCU IULIAN, CĂLIMAN RADU
Today, process industries worldwide demand a low-cost reliable. high performance, general-purpose rotating joint. A corrosion - resistant joint - long thought to be too expensive-may now be in reach
IMPROVING SOLID - LIQUID GRAVITATIONAL SEPARATION BY USING LAMELLAE SETTLING
GAVRILĂ LUCIAN, CONSTANTIN MARIA-MAGDALENA, SIMION ANDREI
The paper presents the basic principles of gravitational separation of solid-liquid systems, and emphasis the ways to increase the equipment productivity. The principle of lamellae settling is analyzed and discussed. Several equipment based on this principle are presented. Advantages and drawbacks of the lamellae sedimentation are also reviewed.
THE INFLUENCE OF PARTICLES DENSITY OVER SEPARATION SPEED
MOŞNEGUŢU EMILIAN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper was present the analysis concerning to variation of critical flow speed, variation which must know for projection, achieve and adjust of equipments which realize separation of particles in air current.
VARIATION OF REYNOLDS NUMBER FROM PARTICLE SEPARATION IN AIR CURRENT
MOŞNEGUŢU EMILIAN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper was present the analysis concerning to variation of Reynolds number, variation which must know for determine the flow regime in which find in particle in aerodynamic separation process. The necessity of knows of these variations, Reynolds number, it helps us of determine flow speed on air.
THE INFLUENCE OF TEMPERATURE OVER SEPARATION PROCESS OF PARTICLE IN AIR FLOW
MOŞNEGUŢU EMILIAN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper was present the analysis concerning to variation of air temperature and influence of this variation over pneumatic separation of particles in air current. The density, viscous and humidity of air it change valour in function by variation of air temperature, thing necessary to know for adjust and project equipment which achieve separation process of particles.
THE DEVELOPMENT OF FOOD INDUSTRY IN CORRELATION WITH AGRICULTURE
NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN, PANAINTE MIRELA
In this paper was present the analysis concerning to report between raw materials which is obtain from agriculture and food industry. Over 90% of production obtains from agriculture become raw material from food industry, to return of production to be destining as raw material from other industries.
CONDITION OF DURABLE DEVELOPMENT OF FOOD INDUSTRY
NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN, PANAINTE MIRELA
In this paper was present the analysis concerning to economical development, activities which is pollution, producing offals and consume resource. The economic activity to the worldwide level increase to five and population to three, but the economic consumption in this period found 95 % on conventional resources, with an increase annual to over 20 %. For that reason the food industry development and the function of these in continuity condition suppose an ensuring rhythmic and constant with prime materials to come proceed from agriculture in proportion to over 90 %. The food industry, in comparative with another economical branch is difference from at deed with can directly action over factors of medium from food quality and indirect from pollutant substance result in the follow process to preparing of food.
STUDIES AND RESEARCHES CONCERNING AGGREGATES AGRICULTURAL CONJUNCT FOR WORK OF SOIL
NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN, PANAINTE MIRELA
In certain condition of work, for saving energy (flue, labour, time, equipments etc.) it is recommended to do soil tillage and fertilization at one passage, achieving a corresponding degree of charging the tractor power. Working qualitative indices in combined works are superior, as a result of totalizing the effects of each work. The advantages of using a combined unit, which at one passage does soil breaking up. Fertilization and preparation of the germinative bed. were: the real flue consumption at hectar decrease by 3-4 times; the real working increase by 2-3 times.
ANALYSIS OF GRINDING PROCESS AT HAMMER MILL
PANAINTE MIRELA, NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN
In this paper was present the grinding process factors of hammer mill, factors which influence the grinding process. Grinding is process to reduction of geometrical dimension on particles, process in which is necessary much energy to grind. The hammer of hammer mill it's submit some variables solicits will be in permanent contact with material
THEORETICAL ASPECTS OF CYLINDER MILL
PANAINTE MIRELA, NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN
In this paper was present the analysis concerning to constructive characteristics of cylinder mill, which is the principal technological equipment for of grind operation. Is necessary to know of these characteristics because this is necessary for project ion, adjust and realize of cylinder mill.
CONSIDERATIONS REGARDING THE RELIABILITY OF THE PROPULSION BELT VARIATORS FROM THE ROMANIAN CEREAL HARVESTER COMBINES
SAFTA VICTOR-VIOREL, VOICU GHEORGHE
The reliability of the cereal combines depends mostly on the reliability of the propulsion belt variators which they are equipped of, because the out of working of the propulsion belt variators immobilises the combines and their restore is difficult and with important period of immobility.The reliability study of the propulsion belt variations consists in the determination of the belt life period, the belts being the variation most sensible elements. In order to determine the life periods of the variators belt, a computer programme was realized based on the variator belt working. The programme results aloud to identifier the most unfavourable regimes and the ways to avoid them.
INDUSTRIAL PROJECT PLANNING
VINTILA CRISTIAN, SCHNAKOVSZKY CAROL
The success or failure of a project is usually judged by whether it achieves specific objectives in time, cost and performance. Project time-scales are always being squeezed by management and there is rarely enough time to complete project work, so it is important to make the best possible use of the available time. Project objectives are achieved by co-ordinating the efforts of a range of people who invariably have different levels of knowledge and experience.
CONTRIBUTIONS TO THE DETERMINATION OF THE FUNCTIONAL PARAMETERS OF THE PACKAGING MACHINES IN FLEXIBLE PACKAGES
VOICU GHEORGHE, SAFTA VICTOR-VIOREL
This paper deals with some aspects concerning the operating process of the packaging machines for flexible thermo-sealing packages. These machines work in a formatting - filling - closing system in vertical or horizontal flow. In the paper are presented some theoretical aspects regarding the determination of the main functional parameters of those machines. Also, there are presented the technical dates of several packaging machines and the synthetic linkage between the functional and the machines parts.
TEMPERATURE IN CYLINDRICAL BODIES SUBJECTED TO MOVING HEAT SOURCES AND SURFACE COOLING
CĂLIMAN RADU, FLORESCU DANIELA, FLORESCU IULIAN, OLARU IONEL
The theory moving heat sources is applied to two models to determine the effect of convective surface cooling on temperature distributions The models chosen consist of a translating semi-infinite body and rotate cylindrical body, each having a band heat source acting on a portion of the surface and the convective cooling acting over the entire surface The analytical results can be utilized to predict temperature distributions occurring in certain machining processes or other processes involving heat sources
TEMPERATURE DISTRIBUTIONS EN SOLID CYLINDERS DUE TO A MOVING CIRCUMFERENTIAL RING HEAT SOURCE
CĂLIMAN RADU, FLORESCU DANIELA, OLARU IONEL
Analytical are presented for temperature distributions in solid and hollow cylinders which are due to moving circumferential ring heat source These heat transfer problems arise in practice in metal cutting Solutions are obtained by the use of finite Hankel transforms.
HIPERBOLIC HEAT-CONDUCTION EQUATION A SOLUTION FOR THE SEMI-INFINITE RING HEAT PROBLEM
CĂLIMAN RADU, FLORESCU DANIELA, OLARU IONEL
This theoretical paper determines the effect of the propagation velocity of heat on the temperature and heat-flux distribution in a semi-infinite body due to a step change in temperature at the surface. The solution yields a maximum but finite heat flux under the conditions of a step change. This a contrary to the infinite value predicted by the error function solution to the Fourier transient conduction equation. In addition, assuming convection is conduction limited, an upper limit for convective heat transfer coefficients is postulated.
PACKED BED ADSORBER OF ROTARY WHEEL TYPE: NUMERICAL ANALYSIS AND EXPERIMENT
DUMITRU COSTIN, PANAITE CARMEN EMA, STADOLEANU OVIDIU VIRGIL
The new air conditioning technologies use rotary adsorbers which simultaneously prepare a process air stream and regenerate themselves by contact with a hot air stream, The proposed thermodynamics model and the computerized algorithm simulate the heat and mass transfer manifesting at the air-solid desiccant interface. The validation test showed satisfactory agreement between theoretical and experimental results.
THE CERAMIC REVOLUTION IN PRESSURE MEASUREMENT
FLORESCU IULIAN, FLORESCU DANIELA
The significant advances in materials science in recent decades have not only brought us silicon wafers, -PIEE coating and heat shields for the space -shuttle, but have also perfected the industrial ceramic.
NEW ASPECT OF HIGH-TEMPERATURE CALENDERING
FLORESCU IULIAN, FLORESCU DANIELA
High-temperature calendaring has recently been.adopted 10 improve the smoothness, glass and printability of paper, without reducing bulk or strength. Steam-or oil-heated rolls may have temperature limitation, but Tokuden rolls can reach 420°C, so paper companies are using them in their high-temperature calendering process.
CORROSION RESISTANCE OF COPPER AND COPPER ALLOYS IN COOLING WATER ENVIRONMENTS
GAVRILĂ LUCIAN*, GAVRILĂ DANIELA**, CONSTANTIN MARIA-MAGDALENA*, SIMION ANDREI*
The paper presents the corrosion behavior of copper and admiralty brass in cooling waters from fertilizer plants. Corrosion types and mechanisms of copper alloys, as well as corrosion inhibitors for industrial applications are also discussed. In chemically treated cooling water, even at relatively high ammonia concentrations, copper and admiralty brass evidence excellent corrosion resistance.
THE EVALUATION OF THE PELTON RUNNERS DESIGN AND MAINTENANCE PARAMETERS
ISBASOIU EUGEN CONSTANTIN, SAFTA CARMEN ANCA, RIZESCU GHEORGHE, ALAMOREANU ELENA
The analyses of working conditions and the study of the behavior in time of the Pelton runners loaded structures attended to the parameters identification that could definitely influences their durability. The fatigue of the runners' materials is changed for the worse because of the chemical medium aggressively and could generate stress state and deformations having an unexpected evolution. For this reason is necessary to developed new methods of risk factors evaluation in the design stage of the runners' conception or in the stage of technical reevaluation of the hydro-mechanical equipment. Reliability and life time estimation for such a hydroagregate by having an analysis of the factors that could influenced the structure integrity is a final option in the practice solution that take choice. The paper proposed gives a method of the durability analysis by combining the effects of critical working conditions of the runners' with the variable loading caused by the corrosive and aggressive medium of working against the runners' material. The runners' structure is static and dynamic analyzed and the parameters of the durability calculus will result. The study case presented in the paper shows the steps of the reliability and durability method estimation and the conclusions will give the practical solutions that must be necessary.
A METHOD FOR THE DETERMINATION OF THE LOCAL TURBULENT FRICTION FACTOR AND HEAT TRANSFER COEFFICIENT IN GENERALIZED GEOMETRIES
OLARU IONEL, CALIMAN RADU
A method is presented for the determination of the distributions of velocity, local friction, and heat transfer coefficients in a forced axial turbulent flow with an arbitrary cross section. The method uses as basis the characteristics of the laminar flow A comparison is made with some experimental results concerning different geometries.
NUMERICAL ANALYSIS OF HEAT AND MASS TRANSFER WITHIN REGENERATIVE ADSORBERS
PANAITE CARMEN EMA, DUMITRU COSTIN, STADOLEANU OVIDIU VIRGIL
In the present paper the simultaneous heat and mass transfer manifesting at air-solid interface of regenerative adsorbers has been analyzed. The equations of the mathematical model derived from the heat and mass balances for air and desiccant applied to a fix control volume in cylindrical coordinates, A numerical method of finite difference type was used. The distributions of the air and solid temperatures, air humidity and water content ratio along axial and angular directions were calculated for adsorption and desorption operations.
OPTIMIZED METHOD FOR THE NUMERICAL CALCULUS OF THE GENERALIZED FORCES DEVELOPED IN NONSTEADY SUPERSONIC FLOW
PINTILIE GHEORGHE, ZICHIL VALENTIN, PANOSCHI CRISTIAN
The paper present a calculus method for the generalized forces developed on a wing placed in no steady supersonic regime using the theory of sources distribution. It is considered that the source's intensity has a spatial-harmonic distribution along the wing's chord. Here, the results (particular, the values of the generalized forces) are no more influenced by the number of the finite elements.
THE OPTIMISATION OF THE AXIAL-FLOW FAN'S WORKING PARAMETERS USING THE DIFFERENT RUNNER BLADE POSITIONING
RUSU ILIE, CALARASU DORU, CIOBANU BOGDAN
The researches in the field of axial fans have looked for improvements of the aerodynamic flow and for some constructive solutions. This paper presents the construction of an experimental axial-flow fan with the nominal diameter of 560 mm, used to study the behavior of the row of blades that have an equal or unequal distance between blades. The possibility of the runner blades disposed on two rows was also taken in consideration.
THE AIR LAMINAR FLOW WITHIN A VERTICAL CONCENTRIC ANNULUS
STADOLEANU OVIDIU VIRGIL, DUMITRU COSTIN, PANAITE EMA CARMEN
The laminar flow of the air between the gap of the rotating inner cylinder and the outer fixed is a laminar flow regime with vortices appearing. In this paper, is presented a simulation of this flow. The distribution of the radial, axial and tangential components of the velocity are shown.
THE TEMPERATURE OF A HEATED FROZEN BODY INSIDE
STADOLEANU OVIDIU VIRGIL, DUMITRU COSTIN, PANAITE EMA CARMEN
In this paper, the conduction equation solution for heating up of the frozen body is presented. This model when the thermals and physicals proprieties of a produce must kept uses. It is about of the food field, when, for this reason, the heat temperature of a frozen produce, which it introduced in a microwaves oven, may known.
A NUMERICAL METHOD FOR THE STUDY OF THE PRESSURE WAVE IN A CASE OF NON-MOVING BAROTROPIC FLUID
TOPLICEANU LILIANA, VIZITIU GABRIELA
This study continue and developed the researches that we made in direction of wave propagation witch resulted was published in other different volume. On present the numerical integration of the hyperbolic system of partial differential equations that define the pressure wave propagation on an infinite pipe line, in specific boundary condition, for the case barotropic fluid and we give the graphic results attached to the numerical integration.
GEOMETRIES FOR THE BURNING CHAMBER AT D103 DI DIESEL ENGINE
ZICHIL VALENTIN, PINTILIE GHEORGHE
The influence of the burning chamber upon the burning process in DI Diesel engines is well known. That's why, the authors had developed, using the finite element method two new geometries for the burning chamber, optimized from the point of view of the energy of the fresh inlet charge into the chamber and from the point of view of swirl ratio into the cylinder. This paper shows how the geometry of the burning chamber may change the ratio of the exhaust gas at a DI Diesel engine.
THE DETERMINATION OF THE SAMPLE DIMENSION IN IMAGE ANALYSIS OF THE HAND SHEETS
ABABEI ŞTEFAN
The determination of the dirt content of the hand sheet in optical analysis is an of- line process. This paper presents a method to determine the dimension of area to be analyzed in order to get a significant result with a certain confidence interval.
SOFTWARE FOR MODELING AND SIMULATING THE FUZZY LOGIC CONTROL SYSTEMS
ABABEI ŞTEFAN
This paper present the capabilities of a modeling and simulating Fuzzy Logic Control Systems software. This software is realized in MATLAB programming domain It was destined to the Industrial Energetic Department students work. By the friendly graphic interfaces, the date inserting, establishment and visualization, are possible.
USING FUZZY LOAD MODELS IN DISTRIBUTION NETWORK MONITORING AND CONTROL
ALEXANDRESCU VIRGIL, CARTINA GHEORGHE, GRIGORAŞ GHEORGHE, POPA COCULEANA, CIUTEA IOAN
Nowadays, the fuzzy set theory is regarded with more interest to be applied to different problems concerning the operation control and development planning of power systems under conditions of uncertainty. In this regard, certain studies use a combination of fuzzy and probabilistic data [1]. In case of an electrical distribution network, there are many uncertainties regarding especially active and reactive power demand. In this paper, a fuzzy approach of power flow analysis in electrical distribution networks is presented. The nodal powers are modeled by using two primary fuzzy variables: loading factor and power factor. An appropriate software product for power flow calculation is used to determine the corresponding state of the network under different loading conditions.
ASPECTS ABOUT THE USE OF THE DECISIONAL MODELS BASED ON FUZZY LOGIC IN POWER SYSTEMS
BARLADEANU EUGEN, POEATA ALEXANDRU
The importance of the economic, ecological and social aspects, the growing number of the decisional processes in power systems field need adequate decisional models. Because the experts' opinions have the form of fuzzy logic, nowadays, decisional models based on fuzzy logic are used. In this paper, a selection methodology among fuzzy models is presented. Some references about this practical utility and for making a fuzzy logic reasoning are made, too. In the paper a fuzzy model is proposed for estimating the environmental impact of the overhead lines, model that considered the opinions of the experts expressed as fuzzy reasoning.
SOME ASPECTS CONCERNINING MULTICRITERION OPTIMIZATION IN UNCERAINTY CONDITIONS
GHEORGHE CARTINA, GRIGORAŞ GHEORGHE
A formulation of the problem for the renewal of the distribution networks is presented in this paper. This formulation treats the problem as a multiobjective mathematical programming problem, which is concerned with the attempt to improve each objective simultaneously. The objectives consist of three important terms: the economical cost, the environment impact and the reliability of the distribution networks. In this optimization problem, it is attempted to minimize the economical cost, environmental impact and to maximize reliability of the distribution networks. The suggested method is based on a dynamic model and heuristic solutions, by use of fuzzy-logic. Some hypothesis are considered in some stages of the process.
ARTIFICIAL INTELLIGENCE MODELING TECHNIQUES IN POWER SYSTEM CONTROL
GHEORGHE CARTINA
We are seeing today that information technology has drastically changed education, the nature of work, society, and decision-making processes all over, among other things. More and more information is becoming available, faster than ever before. The changing face of information technology and communication are proof that the economy, and in particular the power systems sector, have entered a new era of fundamental change. The impact is being felt in the energy market, in the control and operation of the distribution and transport networks. Under these circumstances of momentous change, Artificial Intelligence has the potential to play a more important role. Hybrid technologies, such as neuro-fuzzy, expert-neuro-fuzzy, or neuro-evolutive, can contribute within an integrated framework to realizing more efficient systems for optimum utilization of power systems.
LOAD PROFILING FOR EFFICIENT PLANNING AND OPERATION OF DISTRIBUTION SYSTEMS
GAVRILAŞ MIHAI, NELU MARIUS FILIMON, SFINTES VIOREL CALIN
Load profiles provided by electronic metering devices represent a real mine of information, which can be used in a large range of applications. This paper review the basic concepts about load profiling and presents a technique for typical load profiles extraction that uses self-organization in Kohonen networks. The self-organizing approach needs no more a priori specification of the number of consumer classes to be separated, allows the separation of subclasses and typical load profiles updating procedure due to the load dynamic is greatly simplified. The paper describes the algorithm of the self-organizing technique and a case study.
SOFTWARE APPLICATION PACKAGE FOR STRUCTURE AND STATE OPTIMISATION OF THE DISTRIBUTION NETWORKS, USING CLASSICAL AND BASSED ON EVOLUTIONARY ALGORITHMS METHODS
GEORGESCU GHEORGHE, VARVARA VIOREL, POEATA ALEXANDRU
A software application package for the complex analysis of power distribution networks characteristic regimes and possibilities of their optimization are presented. The analyzed aspects are studied using classical methods and methods based on the evolutionary algorithms (genetic algorithms and evolutionary strategies). The nodal loads are modeled using a database which contains typical load curves for different categories of consumers, on every month and standard days, a complex structure of the consumer from each node and a limited number of measurements (currents and energy) in the network. The obtained results may be useful in the operation and management process and in adopting decisions concerning the planning and the development of distribution networks.
PC-BASED INSTRUMENTATION FOR BREWERY
MARCU SILVIU, VOICU GHEORGHE, TUTUIANU GEORGE-DORU
Beer making is one of the oldest activities known to mankind. Control of manufacturing processes requires information from the persons and machines doing the work in the brewery. A modern brewery requires a lot of instrumentation to monitor and control processes as well as to control the quality of the product in order to increase quality, improve efficiency and reduce costs.
PROTECTION OF THE PULSE-WIDTH MODULATED INVERTERS WITH FUZZY LOGIC
ROTAR DAN, POPA SORIN, ANGHELUŢ MARIUS
Current Control (CC) techniques of the Voltage Source (VS) Pulse-Width-Modulated (PWM) inverters is the key problem in such high performance applications as: AC motor drives and motion controllers. AC power supplies and active power filters. This paper describes a new microcomputer-based protection method of the inverter based of the real time identification of the load characteristics. The application of the proposed on-line control idea demonstrated that a low-cost implementation of complex and advanced control algorithm is possible with microcomputers. The structure of the microcomputer and the interface circuit with the inverter switches are presented. The software tasks and their structures are presented and the time performances are considered. Experimental results illustrate the performances of the proposed method.
FUZZY LOGIC IN SWITCHED RELUCTANCE MOTOR DRIVE COMMAND
ROTAR DAN, ANGHELUŢ MARIUS
The switched reluctance motor (SRM) is becoming to be widely used in the positioning systems or in speed adjusting systems in many industrial and consumer applications and there is a tendency to replace the conventional AC and DC motors. This paper introduces an attempt to use fuzzy logic to control a switched reluctance motor drive based a new controlling method. After briefly reviewing the SRM operation, this paper describes an estimating method of the load torque that proposes an additional control variable so that the energy developed by the rotor can be close as possible to the load energy. An accurate mathematical model is very difficult to obtain from SRM and the usage of this model presupposes sophisticated computations. The fuzzy logic controller is more convenient solution in this case. Simulation and laboratory results are compared and attest the expected features of the fuzzy controller like steady state torque control, robustness and losses' reduction.
NEURAL NETWORKS UTILISATION IN THE HARMONIC ANALYSIS
ROTAR DAN, ANGHELUŢ MARIUS, ANTOCHI MIHAELA
Often for the study of the energetic systems and equipment's behavior, the Fourier analysis is necessary. This paper presents a way for automatic Fourier analysis with the microcomputer. Two methods are presented: a method called conventional method based on automatic identification of the signal period and a neural network method. The Fourier analysis is made with Fast Fourier Transform. The performances of the proposed methods arc presented.
QUALITIES OF QUALITY IN UNIVERSITIES
CRISTEA ION
In the past few years, the framework of the universities' actions has change as much as the sensitivity of universities and their academics to there own actions. Until recently, universities tended to take "quality" -regardless of how it is defined - for granted as an element that is constituted by their mere existence. Now the term has become a buzzword in university politics. Quality assessment, quality assurance and quality development should lend the university legitimacy and serve as criteria for the distribution of shrinking budget. They are also a battle cry in disputes within universities.
SOFTWARE PROPOSAL TO SOLVE A MILITARY PLANNING GAME
BUJOREANU IULIAN
Game theory represents a great field of experiment and application of the decision theory science. This work presents a military planning game, its general rules, and the way it can be solved, through a Microsoft Excel software that speed the processing time necessary to give the two teams, following each stage of the game, data they need to be able to continue. The stages of the game are designed as the two teams "benefit" of maximum uncertainty concerning the future of their investments, although the goal of each of the teams is to maximize their net offensive utils. The teams have also to deal with the cost effectiveness analysis that will allow them to infer the optimum investment in terms of cost and benefits (utils generated).