No. 8 ( 2002)
Articles
EXPERIMENTAL ANALYSIS CONCERNING THE INFLUENCE OF THE ROLLING DIRECTION AND STRAIN RATE ON THE STRESS-STRAIN CURVE IN THE CASEOF A SPE220BH - ZINC COATED - STEEL SHEET
AXINTE CRINA
As a function of different factors of influence, the stress - strain curves in the case of metal sheets will present particular aspects concerning their level and shape. The present paper analyses the influence of some factors such as: rolling direction and strain rate on the level and shape of the stress-strain curves in the case of coated steel sheets.
NEW TECHNOLOGY FOR FOOD GRADE LACTIC ACID FROM STARCHY RAW-MATERIALS
BEGEA MIHAELA, STROIA ION
The described technology is a performance-intensive technology for food grade lactic acid manufacturing from cereals, especially maize. It was elaborated at pilot scale and was applied at industrial scale to produce technical lactic acid and the purification installation will be assemble to obtain food grade lactic acid. In present paper are exposed the research results concerning elaboration of a performance-intensive technology for food grade lactic acid manufacturing from cereals, especially maize.
TECHNICAL RESEARCHES CONCERNING DEVELOPING A TALL TOWER DESIGN PROGRAM
BIBIRE LUMINIŢA, COBREA CODRIN
The authors made researches concerning tall towers predimensioning and checking and they elaborate a mathematical model to create a tall tower design program. The program is meant to increase precision and work speed. This design program may constitute a serious support for specialists.
RESEARCHES CONCERNING DESIGNING TALL TOWERS USING ADVANCEE PRESSURE VESSEL AND PVELITE SOFTWARE
BIBIRE LUMINIŢA, COBREA CODRIN
As inspected the loads on tall towers and analyzing their implications on tower strength calculation, the authors performed some researches on Advanced Pressure Vessel and PVElite design programs. As theoretical calculation support, tine authors used technical data from C02 stripper - Ammonia installation (S.C. SOFERT S.A., Bacau) and Cyclohexanone and cyclohexanonoxyme stripper - Ammonium sulphate installation (S.C. FibrexNylon S.A. Chemical Division, Savinesti).
TECHNICAL STUDIES CONCERNING CALCULATION NORMATIVES OF THE TALL TOWERS
BIBIRE LUMINIŢA, COBREA CODRIN
Design work, construction and installation mounting of the tall towers connote big responsibilities. Overturning or cracking (rifting) of a tall tower may determine the entire installation destruction. The safety level to which the equipment aspire can be given by the technical knowledge level, the research possibilities and capabilities, the quality control scheme, the construction materials used, all these specified in design standards. Analyzing these standards leads us to some conclusions regarding the duality safety -economicity.
COMPARATIVE STUDY CONCERNING INTERNAL PRESSURE DIMENSIONING OF TALL TOWERS ACCORDING TO I.S.C.I.R. STANDARD AND A.S.M.E. STANDARD
BIBIRE LUMINIŢA, COBREA CODRIN
Based on case studies, the authors realized a comparative study regarding internal pressure dimensioning and testing of tall towers to I.S.C.I.R. standard and A.S.M.E. standard. The following tall towers types were used to complete the study: CO2 stripper - Ammonia installation (S.C. SOFERT S.A., Bacau) and Cyclohexanon and Cyclohexanonoxyme stripper - Ammonium sulphate installation (S.C. FibrexNylon S.A. Chemical Division, Savinesti).
METHODS OF REDUCING OR ELIMINATING EFFECTS OF INSTABILITY PHENOMENA THAT OCCUR IN METAL SHEETS FORMING PROCESSES
BRABIE GHEORGHE, CHIRIŢĂ BOGDAN
The main instability phenomena that occur in plastic forming of metal sheets are springback and wrinkling. These phenomena lead to the decrease of the working accuracy by modifying the geometric shape of parts and worsening their surface quality. The present paper presents the technical methods applied to prevent or to eliminate the effects of these phenomena
YIELDING CRITERIA AND CONSTITUTIVE EQUATIONS APPLIED TO DESCRIBE THE PLASTIC BEHAVIOUR OF METAL SHEETS
BRABIE GHEORGHE, AXINTE CRINA
The following laws and criteria can describe the plastic behaviour of materials: yield criteria, yielding law and work hardening law. The yield criterion defines the general level of stresses from which a solid passes in a plastic forming state. The constitutive equations describe the changes in the law of variation of the yielding stresses during the deformation of the material. The present paper analyses the main aspects concerning the mathematical formulation and field of application of the main yield criteria and constitutive equations
EXPERIMENTAL ANALYSIS CONCERNING THE INFLUENCE OF THE ROLLING DIRECTION AND STRAIN RATE ON THE STRESS-STRAIN CURVE IN THE CASE OF A FEP05MB STEEL SHEET WITHOUT COATING
CHIRIŢĂ BOGDAN
As a function of different factors of influence, the stress - strain curves in the case of metal sheets will present particular aspects concerning their level and shape. The present paper analyses the influence of some factors such as: rolling direction and strain rate on the level and shape of the stress-strain curves in the case of steel sheets without coating.
ON-LINE AND OUTLINE MEASUREMENT OF DRILL WEAR
CRISTEA ION
Artificial neural networks are used for on-line classification and measurement of drill wear. The input vector of the neural network is obtained by processing the thrust and torque signals. Outputs are the wear states and flank wear measurements, the learning process can be performed by back propagation along with adaptive activation-function slope. The results of neural networks with and without adaptive activation function slope as well as various neural network architectures are compared. On-line classification of drill wear using neural networks has 100 percent reliability. The average flank wear estimation error using neural networks can be as low as 7.73 percent.
ARTIFICIAL NEURAL NETWORK FOR MEASUREMENT OF DRILL WEAR
CRISTEA ION
Artificial neural networks are used for on-line classification and measurement of drill wear. The input vector of the neural network is obtained by processing the thrust and torque signals. Outputs are the wear states and flank wear measurements, The learning process can be performed by back propagation along with adaptive activation-function slope. The results of neural networks with and without adaptive activation function slope as well as various neural network architectures are compared. On-line classification of drill wear using neural networks has 100 percent reliability. The average flank wear estimation error using neural networks can be as low as 7.73 percent.
RESEARCHES CONCERNING THE ENVIRONMENT CONDITIONS` INFLUENCE UPON THE QUALITY OF THE RED WINES
DABIJA ADRIANA, CIOBANU DOMNICA
The achieved experiments are part of a more complex research, which aim the determination of work methods able to estimate the degradation of red wines and its influence factors in the oxidation-reduction system achieved in the presence of H202. The determinations have shown that oxidation agents from the system, respective H202), experimentally coming to 3,8 mg/1, directly influence the environment acidity, situation in which the wine`s color has been depreciated.
A CORRELATING EQUATIONS FOR FORCED CONVECTION FROM GASES AND UQUIDES TO A CDRCULAR CYLINDER IN CROSSFLOW
FLORESCU DANIELA, FLORESCU IULIAN
A single comprehensive equation is developed for the rate of heat and mass transfer from a circular cylinder in cross flow, covering a complete range of Prandtl number (Pr) and the entire range of Reynolds number (Re) for which date are available. This expression is a lower bound; free-steam turbulence, and effects, channel blockage, free convection, may increase the rate.
THE COMPUTATION OF THE CALENDER ROLLS DEFLECTION USING THE STONE-GAEVSKI FORMULAE
FLORESCU DANIELA, IATAN RADU, FLORESCU IULIAN
This paper presents new models for the change of the internal configuration of the paper calender rolls with extension to those for plastics and rubber, and the deflection calculation procedure using Stone-Gaevski formulae.
LONGITUDINAL STABILITY OF PLATFORMS FOR THE TRANSPORTATION OF TECHNOLOGICAL NO GAUGE EQUIPEMENTS (I)
IATAN RADU, DUMITRESCU VERONICA
The paper presents the calculation relations of the longitudinal stability of a platform with two axles loaded with technological no gauge equipment. We take into account the effect of the whole weight, and of the wind and drag load and of those of friction.
COMPARATIVE STUDY CONCERNING OF SEPARATION PROCEDEEING OF HETEROGENEUS MECHANICAL MIXTURE S-S
MOŞNEGUŢU EMILIAN, NEDEFF VALENTIN, SAVIN CARMEN
In this paper is present a comparative study concerning separation proceeding of heterogeneous mechanical mixture S-S. Separations proceeding over it make the comparative study; include separation of heterogeneous mixture after particles size, particles density, and surface of particles and after aerodynamically property.
STUDY AND RESEARCH CONCERNING THE POSSIBILITY OF VARIATION ON MIXTURE COEFFICIENT OF MIXTURE SEPARATION GAS-SOLID IN AIR CURRENTS
MOŞNEGUŢU EMILIAN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper we present mode to aerodynamic separation of particles taking consideration to variation of vertical flow air pressure, variation that depend to variation of coefficient of mixture air-solid particles. The separation process was observed on vertical separator with one air drain and with more clam room. Determine was make in laboratory for more particles type.
THE CONDITION SURFACE INFLUENCE AND HUMIDITY OF PARTICLES OVER SEPARATION DEGREE IN VERTICAL AIR CURRENTS
NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN, SAVIN CARMEN
In this paper we present mode to aerodynamic separation of particles taking consideration to separation degree of vertical air current, variation which depend, in study case to particles condition surface and humidity from mixture. Determination was making on vertical separator with one air drain and with more clam room, and with materials was use different particles type, which is meet in food industry.
THE FORM INFLUENCE OF SOLID PARTICLES OVER SEPARATION DEGREE IN AIR CURRENTS
NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN, PANAINTE MIRELA
In this paper we present mode to aerodynamic separation of particles taking consideration to variation of vertical air current pressure, variation that depend to particles size and form from mixture. The separation process was realized on vertical separator with one air drain and with more clam room. Determine was make for one mixture, which was form from three particles type whit equally participation of mass.
COMPARATIVE RESEARCH TO REGARDING GRINDING PROCEEDINGS
PANAINTE MIRELA, NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN
Products submissive a grinding operation has characterization of: linear dimension, geometrical surface, hardness, and homogeneity. Too over grinding operation influenced a several factors among which more important has: the physic-mechanic property of particles; constructional and functional parameters at grinding machinery. Through correlation of this factors can obtain the products of quality aggrandizement and efficiency of grinding machinery.
STUDY AND RESEARCH CONCERNING THE POSSIBILITY OF MATERIALS GRINDING WITH VARIABLE TEXTURE
PANAINTE MIRELA, NEDEFF VALENTIN, SAVIN CARMEN
The products submission of grinding operation was characterization for laniary dimension, physics - mechanic property. Of this an important part will have the texture, propriety that must regard in the choosing at grinding proceeding, at of active organs of work, at character of service choice.
STUDY AND RESEARCH CONCERNING MATERIAL MLXED WITH VARIABLE VISCOUS
SAVIN CARMEN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper were the analyses mixed process for materials with viscosity variable. No matters of mixture nature obtained from mixing process, the mixtures from food industry are characterized in dynamic viscosity, kinematics viscosity that influence of final product and the intensity of technological process.
COMPARATIVE STUDIES REGARDING MIXING PROCESSES
SAVIN CARMEN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper were comparative studies regarding mixing processes for liquids with different viscosities realized with propeller mixer and anchor mixer.
ANIMAL FAT AS FOOD PROTEIN SOURCE
STROIA ION, BEGEA MIHAELA
The new biotechnological procedure is based on the development of microorganisms with lipolytic activity (yeasts from Candida and Torula genera) on the culture medium containing animal fat. After complete transformation of existing fat into protein yeast is separated from the culture medium by centrifugation.
ASPECTS FOR ESTIMATE THE ENERGY CONSUMPTION FROM STADIUM GRASSYB HEATING
VINTILĂ CRISTIAN, SCHNAKOVSZKY CAROL
THE USING OF THE POKA-YOKE TECHNIQUES IN ORDER TO AVOID THE TRANSLATION PROGRAMS AND MENU FROM OTHER LANGUAGES
VINTILĂ CRISTIAN, SCHNAKOVSZKY CAROL
Poka-yoke is a quality assurance technique developed by Japanese manufacturing engineer Shigeo Shingo. The aim of poka-yoke is to eliminate defects in a product by preventing or correcting mistakes as early as possible. Poka-yoke has been used most frequently in manufacturing environments. The currently develops its Common Desktop Environment software to run in twelve locales or languages. Traditional testing of this localized software is technically difficult and time-consuming. By introducing poka-yoke (mistake-proofing) into our software process, we have been able to prevent literally hundreds of software localization defects from reaching our customers. This paper describes the poka-yoke quality approach in general, as well as our particular use of the technique in our localization efforts. Poka-yoke is providing a simple, robust and painless way for us to detect defects early in our localization efforts.
CONSIDERATION REGARDING THE INFLUENCE OF THE CURVES OF THE PIECE AND OF THE DIMENSIONS OF THE MOTIF IN THE CALCULUS OF ERRORS OF THE SPECIFIC DEFORMATION METHOD
ULERIU COSTEL DORINEL
Taking into consideration that the measuring techniques, using different systems: mechanical, optical, with electron rays, ultrasonic etc., reached the domain of nanometers, it is necessary to eliminate errors by calculus so that the products be precise, of an extremely high accuracy and realization of the order of nanometers. This paper presents some aspects regarding the calculus of the errors of the specific deformation method according to the curves of the piece and the dimension of the motif. These errors must be taken into consideration so that the tracing of the limit deformation curves be as precise as possible.
ASPECTS REGARDING THE REALISATION OF STAINLESS DECORATIVE AND FUNCTIONAL ELEMENTS IN CONSTRUCTION AND ARCHITECTURE
ULERIU COSTEL DORINEL
Since stainless steel, in construction and architecture, has known an extraordinary development in our country lately, the present work is answering the questions of the people in this business and not only. The presents the methodology of determining CLD for press operations for realizing ornamental products using Wl 4301 prefab material, in sheets. The CLD study proves to be a useful instrument for solving the problems appear in the industrial practice of deforming sheet by press.
THE ENERGETICALLY OPTIMIZATION OF HYDRAULIC DRIVES
BENCHE VICTOR, HUMINIC ANGEL, HUMINIC GABRIELA
The paper presents some considerations concerning the choosing of hydraulic components and ducts dimensioning for the hydraulic drives, in an energetically approach. In addition, the negative consequences of the deviation from indicated parameters are presented.
THE EFFECT OF THERMOCAPILLARY FLOW ON HEAT TRANSFER D DROPWISE CONDENSATION
CĂLIMAN RADU
The effect of fluid flow introduced by surface tension forces on heat transfer through a drop was considered. The model is a hemispherical liquid drop growing on a flat isothermal surface. The solution was obtained by finite-difference techniques for different values of the Marangoni number (Nm) associated with surface tension forces and the Biot number (Bi) associated with heat transfer at the liquid -vapor interface. The ranges of parameters covered by this investigation include the regimes of most practical interest for water. The results show that the contribution of internal circulation in the drops to the increase of heat transfer in drop wise condensation is insignificant.
TAYLOR-GOERTLER VORTICES AND THEIR EFFECT ON HEAT TRANSFER
CĂLIMAN RADU
An experimental measurement of the effect of Taylor-Goertler vortex formation on the heat transfer through the boundary layer on a concave wall has been made. A theoretical analysis based on independent mean and oscillatory flow components indicates that, although the heat transfer rate will fluctuate periodically in the spanwise direction, there should be no overall increase in heat transfer. The experimental results indicate that there is a significant increase in Nusselt number in the presence of the vortices. Interaction between the oscillatory and mean components must be accounted for, if the theoretical model is to reliable.
AN INTEGRAL TREATMENT OF LAMINAR AND TURBULENT FILM CONDENSATION ON BODIES OF ARBITRARY GEOMETRICAL CONFIGURATION
CĂLIMAN RADU
A general solution procedure has been developed for laminar and turbulent film condensation problems. The procedure is designed to deal with both plane and ax symmetric isothermal bodies of arbitrary geometrical configuration. Inertia effects are fully considered by introducing a new parameter associated with the flow acceleration. A closed - form expression for the local Nusselt number is obtained for both laminar and turbulent flows. Calculations are carried out for laminar and turbulent condensate layers developed on flat plates, horizontal circular cylinders and spheres. The results are compared with available predictions and measurements.
EXPERIMENTAL SYSTEM AND PROCEDURES FOR DETERMINATION OF THE AVERAGE CONVECTIVE HEAT TRANSFER COEFFICIENT AT CROSS-FLOW EXCHANGERS WITH TWO-PHASE MEDIUM
DUMITRU COSTIN, LOZONSCHI TEONA, PANAITE CARMEN EMA, STADOLEANU OVIDIU VIRGIL
The paper presents a theoretical and experimental method used to calculate the convective heat transfer coefficient for a cross-flow exchanger with two-phase medium. The influence of the liquid ratio within the mixture on the performance of the heat exchanger was studied.
NUMERICAL INVESTIGATION OF VEHICLE AERODYNAMICS WITH GROUND EFFECT SIMULATION
HUMINIC ANGEL, HUMINIC GABRIELA
Using a prototype of a terrain vehicle as an example, a process for the simulation of flow around the exterior of a vehicle is performed with the aid of the ANSYS 5.6 commercial package (FLOTRAN module). The main steps involved in the simulation process, with a special emphasis on the influence of ground effect simulation, are reviewed. The results and conclusions are demonstrated by the computer-graphics visualization.
LAMINAR WAVY-FILM FLOW: PART I, HYDRODYNAMIC ANALYSIS
OLARU IONEL, CĂLIMAN RADU, MACARIE FLORIN
The hydrodynamic characteristics of thin, laminar, gravity-driven, wavy-film flow are considered. A theoretical model is developed to predict the hydrodynamic features of asymptotic, wavy-flow states. The mathematical closure question arising in asymptotic-state analyses is resolved by incorporating the results of a prior stability analysis of smooth-film flow. Calculated values for mean film thickness, trough-to-crest dimension, wave celerity, and wavelength are found to be consistent with published experimental data for these quantities.
LAMINAR WAVY-FILM FLOW: PART II, CONDENSATION AND EVAPORATION
OLARU IONEL, CĂLIMAN RADU, MACARIE FLORIN
The Nusselt theory of laminar film condensation and evaporation is show significantly underpredict existing experimental data because of the presence of waves or liquid-vapor interface. A heat transfer model is presented which incorporates the results previously developed hydrodynamic wavy-film model (Part I). Results based on the mode both local and mean Nusselt numbers are shown to be consistent with available data, and to satisfactory account for the deviation of the data from the classical Nusselt theory.
AERODYNAMIC TESTS OF FANS ON SUCTION INSTALLATION
RUSU ILIE, CIOBANU BOGDAN, ZAHARIEA DANUŢ, CALARASU DORU, OSADET FLORIN
We present the construction of a stall for aerodynamic tests, for axial and centrifugal flow fans, with a suction room (5000x4000x2500 mm3), on which we have installed diaphragms for the measurement of the flow and plugs for the measurement of the static pressure. The carrying away of the fans we do with a c.c. swing motor, which allow establishing the power of the fan`s runner in a very large range of rotations speed. The stall has a control desk and adequate connection and has the possibility to made tests at different range of powers. For an axial flow fan`s prototype we are drawer the experimental typical curves. The testing methodology, the equations and the way we present the characters curves was settled during several test made at the Department of Fluid Mechanics.
NUMERICAL SIMULATION OF THE FLOW WITH FRICTION AND HEAT EXCHANGE THROUGH LONG PIPES AIDED BY THE IMPROVED STECIKIN MODEL
VARTOLOMEI HARALAMBIE-MIHAIL, COSTIN DUMITRU, STADOLEANU OVIDIU VIRGIL
The numerical simulation is a complex and operative study instrument. Using modern calculation methods we managed to improve the model proposed by Stecikin for fluid flow with friction and heat exchange through long pipes of reduced diameters. Our paper presents briefly and selectively the compared results obtained by rolling in different concrete conditions of the calculation program worked out. Finally we present some conclusions we came to after we analyzed the theoretical possibilities created by using the version of the program proposed.
APPLICABLE METHODS FOR ENVIRONMENTAL IMPACT ASSESSMENT, CHARACTERISTIC FOR THE PAPER REFUSE CAPITALIZATION
CIOBANU DOMNICA, DABIJA ADRIANA
The paper refuse represents the raw material in composition structure of the products resulted from the paper and cardboards industry. The amounts of used paper refuse without to affect for pollution of environment, can`t exceed 20%. In conditions of addition 20% paper refuse in composition of finished product, with to observe the typical technological parameters, frame the system at value of quality index for human habitats at -1, representing the area with destructive effects about life, requiring the pressing measures for the ecological reconstructions.
CONTRIBUTION CONCERNING THE CAPITALIZATION OF BY PRODUCTS, WITCH PROCEED FROM MEAT INDUSTRY
CIOBANU DOMNICA, DABIJA ADRIANA, PAVEL EDUARD
CONTRIBUTIONS FOR CELLULOSE`S INDUSTRY VEGETABLES WASTES RECOVERY ON PHARMACEUTICAL AND FOOD PRODUCTION INDUSTRIES - 1. STUDY FOR ESTIMATE THE POTENTIAL OF AGRICULTURAL, FORESTRY AND PULPING WASTES TO BE USED IN PHARMACEUTICAL AND FOOD PRODUCTION INDUSTRY
CULEA CĂTĂLINA [The other authors were excluded from the article at the request of the lead author]
This paper is about the chemical recovery of lignocelluloses and industrial lignins. One goal is to evaluate the level of vegetal biomass formed by agricultural, forestry and pulping wastes, in our country and in the world. The vast potential of this kind of wastes as a major resource for development is not yet fully realized. The improved management of forests can increase the production of goods and services and, in particular, the yield of wood and non-wood forest products. Forest resources, being renewable, can be sustainably managed in a manner that is compatible with environmental conservation.
BIOCHEMICAL RESPONSES ASSOCIATED WITH DISCHARGES FROM CELL AND PAPER MILL LETEA BACAU UPON THE ECOSYSTEM OF BISTRITA - PART I. AQUATIC INSECT ABUNDANCE/BIOMASS AS INDICATORS OF ORGANOCHLORINE CONTAMINATION
CULEA CĂTĂLINA, MAZAREANU CONSTANTIN, CIOBANU DOMNICA
Cellulose and paper mill effluent is known to affect freshwater biota in various ways. However, its effects on the food chains of aquatic ecosystems from our country haw not been examined. The riparian birds diet consisted of 50-60% insects emerging fn» aquatic ecosystems. This study examined the aquatic insect abundance at sites located upstream and downstream from two pulp mills in Romania during 1997-1999. It a noteworthy that the number of aquatic insect adults from downstream was significant elevated at both mills. The improved reproduction and larger nestlings at downstream sites may be the result of a grater food supply, consistent with the nutrient enrichment effect often seen below cellulose and pulp mills.
BIOMECANICAL RESPONSES ASSOCIATED WITH DISCHARGES FROM CELLULOSE PAPER MILL LETEA BACAU UPON THE ECOSYSTEM OF BISTRITA RIVER - PART II. PHYSIOLOGICAL BIOMARKERS MODIFICATIONS-EFFECT OF PULP AND PAPER MILL EFFLUENT ON INSECTIVOROUS BIRDS
CULEA CĂTĂLINA, CIOBANU DOMNICA, MAZAREANU CONSTANTIN
Cellulose and paper mill effluent is known to affect freshwater biota in various ways. However, its effects on the food chains of aquatic ecosystems from our country have not been examined. The study examined circulating sex steroids, highly carboxylated porphyrins (HCPs), activity of the mixed function oxygenase enzyme 7-etoxyresorufin-O-deeihylase (EROD), the liver somatic index in insectivorous birds at sites located located upstream and downstream from two pulp mills in Romania during 1997-1999, in general, physiological biomarkers in birds located downstream from the paper mill effluents didn`t differ from those at upstream sites suggesting that dietary exposure to this effluents at these sites werw insufficient to elicit responses. Nevertheless, it is noteworthy that 17ß-oestradiol was lower in incubating females at a site downstream from one of the pulp mills in 1 of 2 years. In addition, HCPs in tree swallows downstream from the other pulp mill were elevated significantly. cellulose and paper mills, riveran birds, biomarkers
BIOMECANICAL RESPONSES ASSOCIATED WITH DISCHARGES FROM CELLULOSE PAPER MILL LETEA BACAU UPON THE ECOSYSTEM OF BISTRITA RIVER - PART III. SEASONAL OCCURRENCE OF YEASTS THE RIVER BISTRITA
CULEA CĂTĂLINA, MAZAREANU CONSTANTIN, CIOBANU DOMNICA
This study evaluates the presence amount of yeasts and yeasts/like microorganism in the river Bistrita, in the area of Bacau. The samples were collected through the year from April to March. One hundred and seventy yeast strains belonging to 14 genera and 29 species were isolated from 112 water samples of the river Bistrita. Saccharomyces cerevisiae, Candida maltosa, Aureobasidium pullulans, Cystofilobasidium capitatum, Rhodotorula glutinis, Geotrichum candidum, and Candida krusei were the most frequent. The basidiomycetous yeasts and yeast-like organisms with oxidative metabolism were present in approximately equal numbers to those with fermentative metabolism. Saccharomyces cerevisiae was the dominant yeast and was isolated from 50% of all samples examined and represented approximately one quarter of the yeast community. Yeast densities ranged from 100 to 21,100 CFU per litre. The highest population density was observed in October. Cryptococcus albidus, Saccharomyces cerevisiae, Rhodotorula glutinis, and Aureobasidium pullulans formed the main part of the yeast population in this month.
POSSIBILITIES OF FRESH WATER CONSUMPTION REDUCTION IN LARGE CHEMICAL PLANTS
GAVRILĂ LUCIAN, DANIELA, CASARES MARTIN CAROLINA, SIMION ANDREI
The paper presents the resources existing in a large chemical plant with regard to the water consumption reduction. An intensive operating program of the cooling circuits combined with a better condensate recovery and a proper treatment of wastewaters could reduce the raw water intake up to 60 percent from the actual intake. Consequently, waste water discharge may be decreased with at least 35 percent.
CONTAIN IN HEAVY METALS ANALYSES OF SEDIMENTARY DUST
MACARESCU BOGDAN, NEDEFF VALENTIN, MOŞNEGUŢU EMILIAN
In this paper is present o analyzing about content in heavy metals of which deposition on soil. Quantities of heavy metals remain pressed bound by components and their accessibility, injurious effect of heavy metals on soil life environment remain low.
QUALITATIVE AND QUANTITATIVE CORRELATION BETWEEN SALINITY CHARACTERISTICS OF THE THREE SOIL FACTORS, RAINFALLS AND IRRIGATION WATER
MACARESCU BOGDAN, NEDEFF VALENTIN, PANAINTE MIRELA
In this paper is present relation between saltness characteristics of soil under precipitation influence and water from irrigation. Analyze which make was determined nature (from estimate the value of critical ration of water Re and ratio calculated Ri) and quantity of saltness dissolves in water. The correlation ratios established are useful in forecasting the evolution of some soil ions when it is known the dynamic of total salt content. quality and quantity of saltness.
THE EFFECT OF SOIL PERMEABILITY IN MOBILIZATION OF SOME CHEMICAL COMPOUNDS
MACARESCU BOGDAN, NEDEFF VALENTIN, SAVIN CARMEN
In this paper is present the study and research concerning permeability of soil, permeability that influences the characteristics of soil. For recommendation of European Parliament it makes efforts to promote the biologic agriculture, but in this way we must know characteristics of soil and to foresee pollution of this.
CONTRIBUTIONS REGARDING PURIFICATION OF THE SURFACE WATERS FROM VRANCEA COUNTY
NEDELCU CRISTINA *, CIOBANU DOMNICA **
As part of the economic and ecologic system, the quality of waters exerts a great number of functions relating to the assurance of the environment for the natural aquatic fauna and flora. The evolution of the waters quality for seven areas of local interest in Vrancea county from over a four years periods, 1996 -2000, it emphasized values for the oxygen index (RO). These are analyzed using the method of three determinations (CBOs, CCOMn, CCOCr) and there were pointed out exceeds over the limit of 30%, the case being related to industrial polluting system.
I. POROUS MATERIALS AS SUPPORTS FOR AN ENZYMATIC ALCOHOLYSIS REACTION
NISTOR DENISA, SIMINICEANU ILIE, AZZOUZ ABDELKRIM, MIRON DORU NECULAI, ASAFTEI S., NISTOR P., URSU ALINA
A recombinant cutinase from Fusarium solani pisi was immobilized by adsorption on several zeolites and its activity the water content and water activity. The effects of the zeolite framework composition (including cation nature) and acidity were studied. The results were compared with other commonly used supports: polyamide Accurel-PA6, silica and alumina. Both the nature of the cation and the silica.alumina (Si:Al) ration of the framework revealed to ba important parameters. The accordance with results obtained with silica and alumina.
II. POROUS MATERIALS AS SUPPORTS FOR AN ENZYMATIC ALCOHOLYSIS REACTION
NISTOR DENISA, SIMINICEANU ILIE, AZZOUZ ABDELKRIM, MIRON DORU NECULAI, ASAFTEI S., NISTOR P., URSU ALINA, DRON PAUL IONUŢ
A recombinant cutinase from Fusarium solani pisi was immobilized by adsorption on several zeolites and its activity the water content and water activity. The effects of the zeolite framework composition (including cation nature) and acidity were studied. The results were compared with other commonly used supports: polyamide Accurel-PA6, silica and alumina. Both the nature of the cation and the silica: alumina (Si: Al) ration of the framework revealed to ba important parameters. The accordance with results obtained with silica and alumina.
INVESTIGATION OF THE MICROPOROUS STRUCTURE OF CLAYS AND PILLARED CLAYS BY 129Xe NMR
NISTOR DENISA, SIMINICEANU ILIE, AZZOUZ ABDELKRIM, MIRON DORU NECULAI, ASAFTEI S., NISTOR P., URSU ALINA, DRON PAUL IONUŢ
129Xe NMR spectroscopy of xenon gas absorbed in clays and pillared clays has been used to glean information on the interlayer gallery height of clays before and after pillaring. Two clay minerals were study, a Ca2+ - montmorilonite and Bentonite L. The NMR results indicate that the effective interlamellar spacing of the montmorillonite increased from 5.4 to 8.0A after pillaring with aluminum polyoxohydroxy cations. These data are consistent with X-ray powder diffraction results, which show a corresponding increase in gallery height from 5.6 to 8.4A.
PROTECTION AND SANITATION OF WATERSHEDS
TOPLICEANU LILIANA, VIZITIU GABRIELA
The composition of surface waters retained in lakes and reservoirs is directly related to the inflows of their surrounding watersheds, which are subject to underground and atmospheric exchanges of materials and energy. The paper presents the inflow of watersheds of the surface water and the strategies that must be developed for protect the quality of the water.
ABOUT REVERSE OSMOSIS PROCESS
TOPLICEANU LILIANA, VIZITIU GABRIELA
Reverse osmosis (RO) is a treatment technology that produces high quality water. The paper presents the principle of Reverse Osmosis Theory the main used membranes, the new domain that it used and the major drawbacks.
A STUDY ABOUT THE OZONE TREATMENT
TOPLICEANU LILIANA, VIZITIU GABRIELA
The paper presents the main characteristics of ozone and the large domain of wastewater treatment. Ozone has been used as an alternative to chlorine for many years. It can also be used to eliminate taste and odors, and aids in the removal of bacteria. It is a powerful disinfectant, and inactivates viruses, cysts, fungi and spores, which are not susceptible to chlorine disinfectant. Used to purify drinking water in Europe over 100 years ago, Ozone is coming to the forefront once again.
THE ANALYSIS AND DATA COMPRESSION USING FREQUENCY ANALYSIS
ABABEI ŞTEFAN, CULEA GEORGE, ROTAR DAN
When a sensor must cover a large size area, the information about measured parameter is sampled and, to extract the information about parameter values is necessary. Also, when a large number of data from measurement system are available, is necessary that to furnish a synthetic information to the human operator. A method for data analysis and compression are presented in this paper; based on frequency analysis and wave filtering, this method was tested with a large data set.
A VIRTUAL APPARATUS FOR THICKNESS MEASUREMENT FOR INSULATING MATERIAL IN SHEET FORM
ABABEI ŞTEFAN, PUIU MIHAI, ROTAR DAN
The thickness is an important parameter, which describe the pulp and paper quality. A virtual apparatus was realized in LABVIEW programming environment. It is formed by two components: die first component is a model of ultrasonic pulse propagation and me second component is the measurement apparatus.
THE INFLUENCE OF MEASUREMENT TRANSFORMER IN TOTAL ERROR
ABABEI ŞTEFAN, GHEORGHIU IOAN
The measurement transformers introduce both ratio errors and angle error. This error can have an important influence in energy measurement total error. Finally, the energy balance closing error size is influenced, and to estimate this balance error, the establishing of entire group measurement error is necessary. In this paper, the methods to calculate measurement groups, and the influence in the balance error are presented.
THERMOECONOMIC OPTIMIZATION OF "75 GAS" STEAM BOILER WORKING WITH THE AH) OF PROCESS COMPUTER
CIUCESCU EDUARD
Thermoeconomics is the branch of engineering that combines exergy analysis and economic principles to provide The system designer or operator with information not available through conventional energy analysis and economic evaluations but very important to the design and the operation on cost-efficiency of a system. Introducing the process computer we can know in every moment the price of our product, in this case the price of the steam with the desired quality. In this paper is presented a mathematical model to count a kilogram of steam in order to optimize the exergetic efficiency of a steam boiler
EXERGETIC ANALYSIS-IMPORTANT FACTOR IN PROCESS COMPUTER CONTROL OF 420 T/H STEAM BOILER OF CENTRAL HEATING-AND-POWER PLANTS FROM BACAU
CIUCESCU EDUARD
The importance of developing thermal systems that make effective use of nonrenewable energy resources such as coal, natural gases and oil is very apparent. The method of exergy analysis is suited for furthering the goal of more efficient energy resource use, since it enables the locations, types and the value of waste and loss to be determinated. This information can be used to design thermal systems, guide efforts to reduce sources of inefficiency in existing systems, and evaluate systems economics. Introducing the computer in the management of a steam boiler, the exergetic efficiency of this power plant will increase. Introducing the computer in the management of a steam boiler, the exergetic efficiency of this power plant will increase. This paper aims is to introduce the exergy analysis for the thermal systems, such as 420 t/h steam boiler of Central Heating-and-Power Plants from Bacau.
PROGRAM IN QUICK BASIC TO CALCULATE THE EXERGETIC EFFICIENCY OF 420 T/H STEAM BOILER OF CENTRALHEATTNG-AND-POWER PLANT FROM BACAU
CIUCESCU EDUARD
The method of exergy analysis is a very important way to acheave the goal of more efficient energy resource use, since it enables the locations, types and the value of waste and loss to be determinated. It is known that a computer solves problems by applying prescripted operations on data entered into it The Quick BASIC is a FORTRAN-like soft able to provide high speed of data-processing operations, commonly used for business. Educational and commercial purposes. This paper presents a program conceived in Quick BASIC to calculate accurately and high speed the exergetic efficiency of 420 t/h steam boiler of Central Heating-and-P, Plant from Bacau
SRP-SIMULATOR FOR PETRI NETS
CULEA GEORGE
This paper presents a new simulating program of Petri nets. This program capable of simulating Petri nets which contain thousands of accessible markings, being much better program than those made in die DOS operating system. As a result of Ad simulation, this program can venerate die accessibility tree, with die eventual blockings a it can display all die accessibility makings. In die actual version, die program is able simulate binary and generalized Petri nets.
A NEW MODELING METHOD BASED NEURAL NETWORKS AND PETRI
CULEA GEORGE
This paper intends to present a modeling method that combines neural networks and Petri nets, a method we will term as NPN (Neural Petri Net). The proposed method the advantages of a manner of modeling based both on Pnets and on neural networks. NPN permits a much better modeling of some complex processes we shall describe as possible. The utilization of this NPN method permits the inclusion of neural networks in Petri which provides solutions for the modeling of systems with artificial intelligence or for systems that have a complex evolution.
THE INCREASE ENERGY EFFICIENCY AND THE DECREASE OF ENERGY COSTS IN COMPANY
HAZI ANETA, HAZI GHEORGHE
For selling, a product must be competitive both from viewpoint of price and from viewpoint of quality. At the same time, the company must obtain a profit that ensures working and developing. For that, the fabrication cost must be lower. This cost is determined by the specific consumption of raw materials and by the acquisition price of them. For attainment targets it must be operate on these two directions. In this paper there are presented ways to reduce of the electric energy and fuel cost that can be applied in a company. There are also results obtained in a company that fabrication pulp and paper.
THE DECREASE OF THE ENVIRONMENT POLUTION BY THE OPTIMIZATION OF THE DRYING PAPER
HAZI ANETA
The reorganization strategy of the pulp and paper industry in our on stipulates that this industry must be aligned with the European regulations environmental protection. The fuel consumed in the process of producing the energy necessary for paper fabrication is a pollutant matter. This paper present optimization model of the paper drying process and numerical results obtained ii paper machines. The paper points out the decrease of the specific thermal consumption the fuel consumption and of the emission resulted from the fuel combustion. optimization, drying paper, emission, pollution
THE IMPACT OF QUALITY OF BREAKING MEDIUM OVER THE ENVIRONMENT
POPA SORIN
The load current and the fault current can be interrupted by using breaking devices, and in particular circuit breakers and contactors, using various breaking mediums: air, oil, vacuum and SF6.
APLICATIONS OF SYNCRON BREAKINGS
POPA SORIN
The use of a synchronous breaking reduces the overloads, over currents, and over voltage without influencing the components of the network during the opening and closing operations under electric load, increasing, this way, the safety of the system.
STABILITY ANALYSIS OF A RELAY CONTROL SYSTEM IS ON - OFF ELEMENT WITH GENERALIZED CHARACTERS OPERATING AT SINGLE POLARITY IDEAL CHARACTER
PORTEANU MIRCEA
In this paper is analyzed the stability of a relay control system nonlinear part contains an on-off element with generalized characteristic which may peculiarized ideal characteristics with single polarity. It is shown that these characteristics allow eliminating the self-oscillations in relay control systems likewise as those with or combined positive and negative hysteresis.
CALCULATION AND MONITORING OF THE ELECTRIC POW ER BY USING SPACE PHASOR THEORY
PUIU-BERIZINŢIU MIHAI, ABABEI ŞTEFAN
This paper presents a calculation method of the three-phase networks powers using space phasors representation of the three-phase voltages and currents. Extending space phasor theorv (used in the electrical machines study) to the calculation of the three-phase networks powers, the expressions of these powers in a quadrature two-axis components are obtained. This offers the possibility to implement some power monitoring systems, relatively simple, and of high accuracy.
DEVELOPMENT OF A METHODOLOGY FOR USING FUNCTION ANALYSIS IN FLEXIBLE DESIGN STRATEGIES
RAVEICA IONEL
This paper shows the development of a function analysis methodology for use in flexible design. This is a strategy to identify common areas of existing designs and then form a new `core design` on which the new designs can be based. A full review of current function analysis techniques is given, from which the new systematic methodology is based. The method has three stages: function identification, function description and function systematization. An industrial case study is given with the function analysis of a powered wheelchair.
A COMPREHENSIVE SYSTEM FOR COMPUTER-AIDED TOLERANCE ANALYSIS OF 2-D AND 3-D MECHANICAL ASSEMBLIES
RAVEICA IONEL
Tolerance analysis of assemblies promotes concurrent engineering by bringing engineering requirements and manufacturing capabilities together in a common model. By further integrating the engineering modeling and analysis with a CAD system, a practical tool for product and process development is created. A comprehensive method based on vector assembly models has been development for modeling and analyzing variations in 2-D and 3-D mechanical assemblies. The models are constructed of common engineering elements: vector chains, kinematic joints, assembly datum’s, dimensional and geometric feature tolerances, and assembly tolerance limits. The method is consistent with engineering design practice and is well suited for integration with commercial CAD systems.. Systematic modeling procedures and rules for creating vector assembly models are outlined. Vector assembly models are created graphically and analyzed for variation statistically in an interactive design environment. Examples of a 2-D and a 3-D assembly are presented with corresponding vector assembly models.
COMMUNICATION SYSTEM FOR DSP AND PC COMPATIBLE COMPUTER
ROTAR DAN, ABABEI ŞTEFAN, POPA SORIN
This reports a new technique for communication between a Digital Signal Processing (DSP) controller and a personal computer. In the complexes applications with a hierarchical structure it is necessary a few connections for the transfer of data. The solution allows a supplementary high-speed connection for data transfers.
DSP SOLUTION FOR EXPERIMENTAL TRANSISTOR CHARACTERISTICS PLOTS
ROTAR DAN, ABABEI ŞTEFAN
The paper presents experimental equipment for the transistor characteristics plots. The experimental equipment is based on the facilities of the DSP controllers and allows experimental measurement and particular data limits acquire. The main goal of the transistor characteristic plots is for research and particular sort of the transistors.