Volume 2, No. 14 (2008)
Articles
ENVIRONMENTAL IMPACTS OF PRODUCTS AND STRATEGIES USED TO REDUCE THEM
AXINTE C., CRISTEA I., T. C. KOLIOPOULOS
Environmental impacts can occur at every stage of the product life cycle: from product design, through manufacturing and transport, to use by customers and, finally, disposal at the end of a product's life. Minimizing these impacts is a complex challenge, as well as an opportunity. This paper summarizes the strategies which could be applied in order to diminish the environmental impacts of products along their lifetime.
STUDYING THE INDICATORS OF SORTING DIFFERENT AGRICULTURE PRODUCTS ACCORDING TO THE PARAMETRES OF THE TECHNOLOGICAL PROCESS
BONTAŞ OVIDIU
This article aims to present some experimental results obtained in order to sort the agriculture products on longitudinal oscillations screens. This study intends to outline the factors which influence this process. In laboratory conditions, using a special stall in order to make such experiments there have been tested the following seeds: bean, maize, corn, pea, soy, hemp. At the end of the experiment there have been proved that the process of sorting on screens is influenced by the shape of the holes of the screen, revolution, rotation device, the state of the surface of the seeds and their shape, and the specific loading. Thus the state of the surface of the particles influences in a negative way, together with the length of the rotation device, the separation efficiency. Generally the growth of the specific loading of the screen leads to the lowering the separation efficiency.
A MATHEMATICAL MODEL FOR THE SEEDS LOSSES PREDICTION ON THE CLEANING SYSTEM SIEVES OF THE HARVESTING COMBINES
CĂSĂNDROIU TUDOR, VOICU GHEORGHE, MAICAN EDMOND
This paper presents a mathematical model which, for the first time, squares up to the dimensional analysis theory on the study of the seeds separation process on the sieves from the cereal harvesters' cleaning systems, in order to forecast the system's seeds loses. Seven main parameters of the process were considered and there were determined the dimensionless considerations of similitude, being proposed an explicit relation between them, as a powers product of type: k a b c1 2 3 4 Î = â‹…Î â‹…Î â‹…Î (Î 1, Î 2, Î 3, Î 4 considerations of similitude, and k, a, b, c - coefficients). The proposed equation was tested with experimental data, being achieved an acceptable value for the correlation coefficient R2 = 0.865. The equation allows the seeds losses estimation from the cleaning system, and is useful both to the designers and operators of the combine harvesters.
THEORETICAL RESEARCH OF THE NUMERICAL SOLUTION STABILITY IN THE VELOCITY MEASUREMENT WITH THE HOT WIRE ANEMOMETER
CAZACU MIRCEA DIMITRIE, ANGHEL MIREILLE SORINA
One presents a mathematical model of the viscous fluid flow with heat transfer around the anemometer hot wire and also in its interior, where is produced of the electrical current distribution caused by the different electric resistances as function of local temperature the conductor wire being supposed at an electric voltage on its ends. For the solving of different equation systems in the two domains, one uses their numerical integration on a polar grid, assuring the solution stability and taking into consideration the specific boundary conditions.
CONTRIBUTION REGARDING THE BIOLOGICAL WASTE TREATMENT/STABILISATION
CIOBANU DOMNICA, IONIŢĂ IRINA, TULBURE MONICA
Mechanical biological treatment comprises a combination of mechanical and biological processes that further treat mixed residual waste before disposal. The aim of this process combination is to minimize the environmental impacts of end disposal and to gain some further value from the waste through the recovery of recyclables and, in some cases, energy. The possible process configurations are numerous although consisting always of mechanical processes and a core biological treatment. With rising environmental standards and higher recycling requirements, integrated systems have been developed that combine the two technology stages as an integrated entity and include treated biologically and odor control facets within a closed cycle.
ESSENTIAL TECHNICAL PARAMETERS USED IN THE MANAGEMENT OF ENERGY SUBSYSTEMS THAT BELONG TO PRODUCTION SYSTEMS
COVRIG CLAUDIU, MĂRĂSCU-KLEIN VLADIMIR
The paper presents the place of the energy subsystem within the production system and the technical parameters used in its management, considering beside the conventional energy systems, the renewable ones which are capable to offer real solutions for a sustainable development. These solutions contribute to a preservation of the global energy reserves and to a reduction of the global pollution.
ESSENTIAL ECONOMIC PARAMETERS USED IN THE MANAGEMENT OF ENERGY SUBSYSTEMS FROM INDUSTRIAL ENTERPRISES
COVRIG CLAUDIU
The present paper treats three important economic parameters used in the energy management of an enterprise: the acquisition cost, the payback time and the average rate of the energy expenses. Calculations are done and conclusions are taken regarding the evolution of these parameters, when implementing within the enterprise the renewable energy producing systems, as sustainable development solutions.
COST ESTIMATING IN THE SHIP DESIGN
CRISTEA ANIŞOARA-GABRIELA
Shipyards, whether doing ship repair or new construction, typically have to deal with a highly variable product or service to perform. This high degree of variation means that bidding on contracts can be extremely difficult, especially in a very competitive market. With minimal profit margins and precious little time available to make bids, the pricing of new work can be hazardous unless there is a quick and accurate means for developing reasonable and reliable cost estimates.
MODELLING TIRE-ROAD CONTACT FOR EARTHMOVING MACHINE
CARMEN DEBELEAC, GHEORGHE OPROESCU
Tire characteristics play a very important role in earthmoving machine dynamic analysis. For vibration analysis of the structure machine, the contact tire-road needs to be simulated. In this paper, the authors present a numerical method to solve the non-linear contact problem between a tire and the road. A non-linear contact model is used to determine the kinematical parameters and contact force of the tire is rolling on a rough road. The contact force is used to calculate the response of the tire.
UNDERSTANDING ELECTRICAL COSTS
DIACONESCU IOANA, GRIGORESCU LUIZA
This paper represents an experience that many energy managers must have for a fundamental understanding of the many variables that make up the costs of electrical energy. Each electrical utility is different. The rate structure, the power generation mix, the reserve capacity, the state regulation under which they operate, the efficiency with which they operate-all are different. For the cost is important to define utilities and find out about their characteristics.
EXERGETIC ANALYSIS OF RECOVERY ENERGY PROCESSES
DIACONESCU IOANA
The paper presents the results of an applicable research where the aim was to establish the real energy efficiency of the heat pump for industrial practices to recovery energy resources with low thermal potential. The exergetic analysis put on user’s disposal the real figures referring to the energy efficiency of the heat pumps. On a qualitative analysis the paper establishes the real limits of energy efficiency for the heat pumps used into recovery processes of secondary energy resources with low thermal potential.
FERROFLUIDS AND MAGNETORHEOLOGICAL FLUIDS USED IN ELECTROMECHANICAL DEVICES
DRAGOI D. D., BESLEAGA CR
The ferrofluids or the magnetic liquids are biphasic mediums obtained by physicochemical procedure to confer properties to some liquids and which integrate into their structure ultra fine, ferro and ferromagnetic subclass magnetic particles stabilized with certain substances. The extremely reduced dimensions of the particles within 0.30 - 20 nm (in the region of 10 nm, in a typical way) give a special role to their movement of thermal agitation in maintaining stability
THE GENERALS CONSIDERATION OBOUT THE FERROFLUIDS AND THEIR ABILTTY IN NANOTEHNOLOGY
DRAGOI D. D., BESLEAGA CR
Nanotechnology is the science of controlling matter with dimensions between 1 and 100 nanometers. This includes manipulating individual molecules. It is a multidisciplinary field consisting of physics, biology, chemistry, medicine, engineering, and nearly any other applied science. The prefix nano- means ten to the minus ninth power, or one billionth.
COMMUNICATION IN PROJECT MANAGEMENT
DROB CATALIN
This study aims is to present the main aspects regarding communication in project management. The processes involved in the communication in project management are: communication planning, information distribution, performance reporting and administrative closure. These processes interact with each other and with other processes regarding project management.
MECHANICAL SIMULATION OF THE HEAVY PLATES COLD - ROLL - BENDING
DUMITRESCU ALEXANDRU TRAIAN
In the elementary bending theory it is usual to admit the hypothesis of small strains, small enough to neglect the transversal stresses induced by severe curvature. It is also admitted that the neutral surface coincides, during deformation, with the central plane of the plate. To carry out a mechanical modeling of heavy plates bending, for the big diameter tube, it is necessary a general theory of plate bending, without restrictions regarding the magnitude of strains and curvature; it is also necessary to determine the neutral surface movement and the movement of each fiber across the plate thickness. The paper presents a model of strains and stresses calculus for both a rigid-plastic material and for a hardenable material. An important issue of these calculi is the width determination of the zone where the material suffer, during bending, both an elongation and a compression and so, the Bauschinger effect has an important influence on the mechanical proprieties of tubes. In this zone the material strength after bending is less than the plate strength, the strength diminishing being proportional to the width of mentioned zone.
CORROSION PHENOMENA MANIFESTED TO THE HEAT EXCHANGERS THAT ASSURE THE COOLING OF THE REACTOR EFFLUENT FROM THE CATALYTIC REFORMING INSTALLATION
GEORGESCU LUCIAN, APOSTOLESCU MARIA, GEORGESCU OVIDIU, PETRESCU MARIUS GABRIEL, GEORGESCU ANA-DANIELA
The heat exchangers that assure the effluent reactor cooling from the installation Catalytic Reforming installation are built from carbon steel. After a relative short work time, about 2,5 years, it was necessary the beam cleaning and the stuffing of the pipes and after another 1,5 years it was replaced the tubular beam. To the external part of the pipes beam where the carbon steel is in contact with the effluent and to the internal part of the pipes in contact with the recycled water there are point - like deposits and also deposits having aspects of oxide, metal sulphide layers and fouling under which it appears local corrosion forms. In the paper there is studied the behavior of the carbon steel and brass to corrosion in the technological environments from the installation and it may be noticed that the brass presents advantages superior to the carbon steel for the construction of the tubular beam.
SOME ASPECTS CONCERNING THE TRANSFORMATION OF RESIDUAL AUSTENITE IN MARTENSITE AT THE CRYOGENIC TREATED BEAR STEELS
GHEORGHIAN MIRELA, CIUCESCU DORU
The treatment under 0oC it is imposed to the pieces in which the residual austenite is not wished by the negative effect on the physico – mechanical properties and on the dimensional stability. The classic treatment can not assure the rotation precision on the bear steels, giving a quantity of 10 – 18 % residual austenite. In this paper the influence of cryogenic quenching temperature on the kinetics of austenite – martensite transformation.
PARAMETRIC DESIGN OF WORM GEAR ASSEMBLIES
GOANTA ADRIAN MIHAI
The paper advances a 3D modeling of all components of a multipurpose anchor winch. The winch consists of a driving lever, braking lever, driving system, drum, frame and band brake. The paper gives a brief description of the parametric 3D modeling stages by making use of the Mechanical Desktop 6 software.
A NEW RC CURRENT MODE OSCILLATOR
GRIGORESCU LUIZA, DIACONESCU IOANA
This paper refer to a group of constructive elements with which, (through adequate combinations) one can generate current mode RC oscillator transfer functions. Obviously this elements set is not unique. From the multitude of possible solutions only the solutions that accommodate the below conditions stand out: the active elements can be easily produced in monolithic technology; each oscillator must have two resistors or two capacitors connected to the mass. The latter requirement is very important for the oscillators with variable frequency. It was made a RC oscillator and its transfer function, and it was made a study of errors which affects maintaining gain of oscillations and frequency of oscillation. The paper point out the experimental results obtained through RC oscillator implementation with PA 630 current conveyors showing that the current mode oscillators appears to be an interesting approach from the perspective of the simplicity/performance compromise.
ARRANGING DISSIMILAR CENTRIFUGAL PUMS IN SERIES AND PARALLEL
HASSAN HAYDAR
While series or parallel arrangement is acceptable for some applications, arranging dissimilar pumps in series or in parallel may lead to problems, especially if one pump is much larger than the other. Also, to avoid pump damage and loss of combined net head, any individual pump should be shut off and bypassed at flow rates larger than that pump's free delivery, so this curve indicates.
THERMAL SOLICITATIONS IN MONOLAYER ANNULAR PLATES I. TEMPERATURE VARIATION ALONG THE RADIUS
IATAN I. RADU, POPA T. CARMEN
This paper propose to show a number of variation lows of the temperature along the radius of an annular plate, keeping the constant values on its thickness, and having the purpose to evaluate the radial displacements and the radial and annular stresses. For the theoretical analyze, we will take into account that the plate is embedded on the external contour and the internal contour is free. In this sense, the expressions of the magnitudes necessary to determine the admissible maximal values of the developed temperature in diverse practical situations are offered, taking into account the complexity of the industrial processes on one side, and the conception of some adequate mechanical structures, on other side.
RESEARCH REGARDING THE ADHESIVE WITH VERY LOW EMISSIONS OF VOLATILE ORGANIC COMPOUNDS
IONIŢÄ‚ IRINA, CIOBANU DOMNICA, TULBURE MONICA
The floor covering adhesives have been deeply modified during the years. The first major development was the formulation of polymer-based products in aqueous dispersion as an alternative to organic solvents. To minimize both indoor and outdoor pollution, Mapei went further on formulating solvent-free adhesives with very low potential emissions even in the long term. Developing these adhesives required the parallel development of methods for monitoring and analyzing the formulations' emissions over time. A laboratory "environmental test chamber" was built for the purpose. Adhesive is placed on glass plates that are inserted into the test chamber. A stream of air is forced through the chamber and all the volatile organic compounds are collected and analyzed by means of gas-mass chromatography. A thorough analysis of the large quantity of results made it possible to establish a bi-logarithmic correlation of emissions vs. time from which the overall emission behavior from the 24-, 48- and 240-hours measurements can be predicted in sufficient approximation.
STUDY REGARDING THE METHOD TO CALCULATE THE VAPOUR PRESSURE OF HYDROCARBON SOLVENTS FROM SIMPLE PHYSICO-CHEMICAL PROPERTIES
IONITA IRINA, CIOBANU DOMNICA, TULBURE MONICA
It is important to note that hydrocarbon solvents, in spite of their complex composition, are regarded as substances and there fore have one vapor pressure value, just as they have ore flash point value. The objective of this work was to develop arid validate a calculation tool, applicable for the determination of the vapor pressure of hydrocarbon solvents based on readily available physic-chemical properties of the substances. At vapor pressures below 0.1 kPa, many of the measurement techniques, inch as ASTM D323 [3], are not applicable, for suitable methods, sample preparation and handling, and actual measurement are extremely time-consuming hence, in practice, such methods cannot be applied routinely.
EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE CUP DRAWING PROCESS OF ANISOTROPIC STEEL SHEETS
IORDACHE M., AXINTE C.
In order to obtain flawless pieces during the deep drawing process it is important to control the value of the blank holder force. An important value of the blank holder force limits the gliding of the steel sheet and develops its radial elongation. On the other hand, if it is not too big, the steel sheet can easily glide and the compressing stress which appears can cause the steel sheet's folding. The article presents the influence of the blank holder force on the variation of the cupped specimen's thickness in the case of cup drawing process. The results obtained through this simulation are compared to the experimental results. The simulation was performed by using the ABAQUS/Explicit v6.5 program.
NUMERICAL STUDY OF LIQUID-SOLID SEPARATION PROCESS INSIDE THE HYDROCYCLONES WHIT DIFFERENT GENERATRIX OF THE CONE
IPATE GEORGE, CASANDROIU TUDOR
Hydrocyclones are getting more and more interest from various industries. They are widely used to separate particles from liquid. Modeling of complex and multiphase flow behavior inside the hydrocyclone is done usually with the help of computational fluid dynamic study. Current study involves numerical investigation of separation performance characteristics of the hydrocyclone using new design parameters. The Reynolds averaged Navier-Stokes equation employing k-e turbulence model were solved to calculate the turbulent flow field in a hydrocyclone. The particle trajectories were computed by integrating the force balance equations on particles based on the predicted flow field. The separation efficiency defined as the fraction of particles recovered to underflow was obtained by using the calculated particle trajectories.
AN EFFICIENT ITERATIVE LINING METHOD FOR THE MANAGEMENT OF CLOTHOID SPIRAL MANUFACTURES IN TECHNICAL DESIGNS
KOLIOPOULOS T. C., AXINTE C., KOLIOPOULOUS G.
This paper presents a quick and accurate lining method, which confrontates the most common met problems in the manufacture management of several structures and machineries. An analysis is presented for manufactures within the field of clothoids spirals geometries. Proper solutions are presented for the examining problem in order to develop effective life cycle lining methods for the diagnosis and civil defence of the manufactures. In the end, useful conclusions are are made for the lining, assessment, construction and maintenance of machineries and infrastructure works.
NEW CHALLANGES OF THE ECONOMIC ORGANIZATIONS, NEW BEHAVIOURS OF THE PEOPLE IN THE FUTURE
LATU LAZĂR
The organizations will never been what they used to be. But neither the employees will be what they used to be, and in the future, we will not be able to ask them: ”What do you do for a living?”, which meant until today “What kind of job do you have?”, but, together with moving the work outside the organization, we will ask them: “What do you do with your time?”. Work has changed its meanings and its patterns. This affects our feeling of identity, our families, our roles, our whole life style changes. The message is clear: Times change, organizations change, and we must change together with them. World changes because the organizations on the work market change their patterns. At the same time organizations themselves must adapt to a work world which is in a continuous change.
THE SIMULATION BEHAVIOR OF BURGERS VISCOUS-ELASTIC PARAMETRICAL MODEL USED IN VIBRATION ACTIVE ISOLATION
MARIN CORNEL
Dynamic models used in shocks, vibration and seism calculus are based on rheologic configuration which are specifically used in isolation system. The BURGERS parametrical model presented in this paper is used for the behavior characterization of some of these special isolation materials. This is a parametrical model regarding the stiffness of two HOOKE elements (parameter N) and the damping level of two NEWTON elements (parameter M). The present paper gives some numerical results of the simulation of different values of damping and parameters N and M.
OPTIMIZATION OF THE DUST COLLECTION PROCESS OF ELECTRIC-FILTER IN A BIRD CAGE BREEDING POULTRY FARM
MIHAILOV N., KIRIAKOV D.
Optimization of the dust collection process of tube-typed electric-filter in a cagebreeding poultry farm has been made. The influence of the air-flow velocity and the discharging voltage on the dust collection process has been researched. A model has been constructed, which allows the optimization of the electrical filter parameters.
STUDIES ABOUT THE INFLUENCE OF THE BULK DENSITY OF SOLID PARTICLES MIXTURE ON THE PROCESS OF AERODYNAMIC SORT
MOSNEGUTU EMILIAN FLORIN, NEDEFF VALENTIN, PANAINTE MIRELA, SAVIN CARMEN
The aerodynamic sorting process represents a complex process, and depends on different factors (sizes, shape, density and surface). To understand this process it is necessary to take into account the influenced factors. Because the density of the particle is changed, this change influences the floating speed of the particle. Aerodynamically separation of particle mixture taking into account the bulk density is possible, but is not so emphasize. The component of mixture are collected in the first collection boxes, the significant differences is made when we have 80 % particle with humidity 14 % and 80 % particle with humidity 24 % to an quantity of air 0,05 m3/s.
EROSION – CORROSION WEAR MODEL MAPS FOR THE VALVE OF CRUDE PETROLEUM EXTRACTION PUMP CONDITIONS
NEGRIU R. M., DRAGOI D. D., BESLEAGA CR, SARLEA I.
This paper describes erosion - corrosion wear model of carbide materials in crude petroleum fluid flow. The wear model is based by elastically or plastically fatigues, when the corrosion fluid has solid particles. The velocities of solid particles are evaluated by the Reynolds equation. Mathematical model for solid particle has been combined with those for crude petroleum corrosion. This has been addressed through the ball valve of crude petroleum extraction pump. The paper describes some new theoretical developments on the above work. The synergic effect of erosion and corrosion rate was observed for carbide and ceramic composites.
NEW COMPOSITE MATERIALS FOR CRUDE ETROLEUM EXTRACTION
NEGRIU R. M., DRAGOI D. D., BESLEAGA CR, SARLEA I, ONCIUL F.
The paper is concerned with the life of the valves made from different composite materials used in crude petroleum extraction pump. The main problem is the ability of the valves’ material to withstand erosioncorrosion wear due to the crude petroleum. The valves material WC-Co are recommended for crude petroleum extraction with high abrasive action and average corrosive environment and WC-Ni are recommended for crude petroleum extraction with densities 0.8 – 0.92 g/cm³ in high corrosion environment and constant abrasive action. For densities up to 0.8 g/cm3 it is recommended the ceramic balls (ASMC grade) and the seat from the system WC-Co and/or (WC-Ni), as function of the corrosion of the crude petroleum.
THE ADJACENT BUILDINGS MONITORING REGARDING THE TUNNEL CONSTRUCTIONS IN A BIG CITY
NETCU CĂTĂLIN, PANAITESCU VALERIU
This paper presents a new strategy for determining an optimum position of monitoring point and criteria with which judgment is made if the settlement values at the point are critical or not for a significant structure adjacent to tunnel construction. The position and criteria are differently given to each structure by considering its geometry and exact position. It is unlikely to the conventional monitoring scheme undertaken by a fixed criterion applied at certain monitoring points that are also intuitively placed. The strategy proposed is based on an iterative scheme by incorporating the so-called Intelligent Tunneling Information System (ITIS). Details of the iterative procedure are described with an illustrative example. In the example, the settlement criteria at three different damage levels are given at an optimum monitoring point.
STRUCTURES D’ENCADREMENT TECHNIQUE / ACCES A LA TERRE ET INTEGRATION SOCIOECONOMIQUE DES FEMMES DE LA COMMUNE DE BUYO (SUD – OUEST DE LA COTE D’IVOIRE).
N'TAIN YEMOU JEANNE, NEDEFF VALENTIN, PANAINTE MIRELA, MACARESCU BOGDAN, MOSNEGUTU EMILIAN
Jusqu’à une époque récente, Selon Saito et Weidman (1990), les services de vulgarisation ciblaient uniquement les hommes, en partant du principe que les femmes profiteraient de leur apport par un « effet de retombée » ou effet induit. Ainsi, l’étude de la présence des structures d’encadrement technique en relation avec le degré d’intégration des femmes de Buyo, par la méthode d’échantillonnage par quota, montre que le simple contact des femmes avec ces structures fait naître en elles l’espoir et le sentiment d’être impliquées entièrement dans le développement économique et social de leur zone. Le traitement statistique par le test T de student indique une différence significative entres ces deux variables. Relativement à la propriété foncière, les différents modes d’accès à la terre sont : le mode associatif ; le mode familial et le mode personnel. Les résultats montrent que les femmes qui acquièrent la terre par le mode associatif se sentent mieux intégrées au plan social et économique que leurs homologues qui reçoivent la terre par le truchement de leur famille, par achat ou location. Somme toute, les résultats de l’étude indiquent que le mode d’accès à la propriété foncière détermine le degré d’intégration économique et social des femmes de Buyo dans le développement de leur localité
TYPE D’ACTIVITES ECONOMIQUES ET INTEGRATION ECONOMIQUE ET OCIALE DES FEMMES DE LA COMMUNE DE BUYO (SUD- OUEST DE LA COTE D IVOIRE).
N'TAIN YEMOU JEANNE, NEDEFF VALENTIN, PANAINTE MIRELA, MACARESCU BOGDAN, MOSNEGUTU EMILIAN
Les femmes de Buyo interviennent dans les domaines de l’agriculture, du commerce et des services. La technique d’échantillon par quota a permis de construire l’échantillon proprement dit. Ainsi, les résultats de l’étude du type d’activité en relation avec le score moyen d’intégration socioéconomique, par le test T de Student, indique une hiérarchisation des activités avec dans l’ordre décroissant les agricultrices, les commerçantes et les prestataires de services. Somme toute, l’étude montre que le type d’activité exercé par les femmes de Buyo influence leur degré d’intégration socioéconomique dans leur localité.
TORCH BRAZING FOR BRAZED HEAT EXCHANGERS
OLARU IONEL, CALIMAN RADU, AVRAM VASILE
Torch brazing is commonly used on copper, brass, and other copper alloys, as well as steel, stainless steel, aluminum, carbides, and various heat-resistant materials. Brazing can be described as the joining of two components by a coalescence of the surfaces in contact with each other.
RESEARCH CONCERNING DESIGN OF BRAZED PLATE HEAT EXCHANGERS
OLARU IONEL, CALIMAN RADU, AVRAM VASILE
Brazed plate heat exchangers are carving a big chunk out of the heat transfer industry with their compact size and high efficiency design. Brazed plate units are up to six times smaller than alternative methods of heat exchange with the same capacity. This is because of their unique construction: more then hundred corrugated stainless steel plates are brazed together with every second plate turned 180 degrees.
LIFETIME OF PRESSURE VESSELS WITH CONSTRUCTION ERRORS
PĂUNESCU MIHAELA, TACĂ CONSTANTIN
In the present paper is presented a theoretical research about the lifetime determination of cylindrical pressured vessels with errors of construction. It's a matter of the eccentricity error between the cylinders from which is formed the body of vessel. In the same time is taking into account the crack presence in the thermal influenced zone of welding joint and of the fatigue conditions work of vessel, which is stressed with a pulsating cycle.
THE OPPORTUNITY TO CHOOSE THE REGIMES FOR THE HEAT STRESS RELAXATION OF THE LARGEST EQUIPMENTS
PETRESCU MARIUS GABRIEL, BUCUROIU RODICA
In the paper there are presented the principles, the conditions and the working algorithms with which application assure optimal conditions from the technological and economic point of view for the direction of the stress relaxation heat treatment applied to a largest device in welded structure.
MODERN TECHNIQUES IN THE DIRECTION OF THE GLOBAL HEAT TREATMENTS APPLIED TO LARGEST DEVICES
PETRESCU MARIUS GABRIEL, NAE ION, BUCUROIU RODICA
The paper includes aspects specific to the design and the direction of the global heat treatments (GHT) applied to the largest static devices. There are studied the combustion processes specific to the GHT in the variant of heating with flame inside the largest structure. The elaborated calculus algorithm is finalized under the form of combustion diagram and is the base of the recommendations concerning the correct combustion leading, specific to the periods of heating and maintenance of the device to the temperature of heat treatment.
MAGNETIC FIELD MEASUREMENT FOR LOW VOLTAGE AUTOMATIC CIRCUIT BREAKER
POPA SORIN EUGEN
In this paper I present the measurement of the magnetic field around the low voltage automatic circuit breaker in different scenarios. The measurements are taken from two different axes, and will be compared with values obtained from mathematical simulations. The methods that are used are elaborated by the author in his doctoral paper work.
ON THE THERMOELECTRIC PROPERTIES OF ZINC OXIDE FILMS PREPARED BY D.C. MAGNETRON SPUTTERING
RUSU D.I., RUSU I.I.
The dependence on the temperature of the electrical conductivity during the heat treatment is studied. After this treatment consisting of several successive heating/cooling cycles, the structure of the ZnO films becomes stable and the dependence of the electrical conductivity on the temperature becomes reversible. Two series of ZnO films obtained in similar technological conditions are submitted to thermal treatment in vacuum and air respectively the nature of the electrical conductivity variation during the heating and cooling of the film (when the thermal treatment takes place in air) is discussed.
FUNCTIONAL AND INFORMATIONAL MODEL OF EXPERT SPECIALIZATION USING IDEF STANDARD
ŠERIFI VEIS, DAŠIÆ PREDRAG, DAŠIÆ JOVAN
For process of modeling are developed suitable CASE tools. In the course of building this process a standard is used for functional modeling of IDEF0 realized through BPWin tool. Family of integrated IDEF methods presents basic tool of some modern strategies and methodologies of business process improvement, like for example: BPR, CPI, IPD, TQM etc. In paper is given functional and informational model of ″Process of expert specialization of employees in education″ using graphical language IDEF0 that is, CASE Bpwin tool.
SOME ASPECTS OF THE SRESSES APPEARING IN THE CASTS
SIMIONESCU GHEORGHE, CIUCESCU DORU
In the foundries is very important to understand and to control the stresses appearing in the casts. The stresses conduct to cracks, wherefrom the importance of the phenomenon. This paper is an attempt to present some aspects concerning the appearing of the stresses in the casts.
SOME ASPECTS OF APPEARING MECHANISM OF HOT CRACKS IN THE CASTS
SIMIONESCU GHEORGHE, CIUCESCU DORU
The protection against deterioration and failure of materials includes to understand and to control the hot cracks appearing in the casts. As a general rule, the control of solidification means producing of a structure containing a large number of small equiaxed grains. This paper is an attempt to present some aspects concerning the appearing of hot cracks in the casts.
SOME ASPECTS REGARDING THE DURABILITY OF SELFPROPELLED TIRE-WHEELED VEHICLE COMPONENTS FOR BUCKET TRANSPORT FOR CONSTRUCTIONS
SARBU LAURENTIU
Self-propelled transport vehicles of articulate bucket type for constructions include loaders or automated dumpers for sites, with buckets for ground transport. This paper presents the calculation of the fatigue interval for the moving element of the selfpropelled vehicle with tires, considered as an in line vibration system, and the working functions are represented by the micro-profile of the road (stationary ergodic processes). A relationship is stressed out between dynamic processes and structural stresses determined by these processes during the work. The spectrum vibration theory allows, once the mechanism working character is known, a complete arrangement of dynamic tension distribution places. The calculation method for the fatigue interval, in the case of vehicle parts, is based on the cumulative fatigue defects theory. With these details in mind, the “narrow band” type process is determined.
THE EFFECT OF DYNAMIC STRESSES DETERMINED BY ROAD DISLEVELMENTS ON THE STRUCTURE OF TIRE WHEELED LOADERS USED IN CONSTRUCTION SITES
SARBU LAURENTIU
The study of vibrations of a self-propelled vehicle is made with the help of simplified dynamic models with a degree of freedom determined by the allowed degree of freedom existing between various subassemblies. This paper is a commentary of the analysis referring to the measurement of vertical accelerations for non-suspended masses (wheels), frame joint, cabin floor or seat, as well as vehicle translation speeds and accelerations for various types of roads, road excitation being an random stochastic process. Dynamic performance and car comfort are determined by the quality of the drive, breaking, and operation systems. Longitudinal accelerations are dynamic characteristics while speed and the impulse (impact force) developed during work determine the tensile strength of the car. For modern loaders, these values are measured by sensors which are limiting the engine drive operation, as well as the functioning of the drive system, thus ensuring an optimal functioning of the entire vehicle.
MICROCRYSTALLINE PULP - MANUFACTURE, CHARACTERIZATION AND USE IN THE FOOD INDUSTRY
STANCIU CONSTANTIN
Summary: This paper shows the research carried out concerning the manufacture (mechanical or chemical manufacture) of microcrystalline pulp from beech dissolving pulp. The results of its use in various branches of food industry are shown (filter material, additive etc.).
STUDY ABOUT TIGHTNESS ASSURANCE OF STUFFING BOXES
TACĂ CONSTANTIN, PĂUNESCU MIHAELA
This paper presents the results of an experimental research regarding the tightness of stuffing boxes used for the shafts in rotation move. With the experimental installation that is presented in this work is possible to control the compression force of packing rings and, simultaneously, the shaft's power input.
STUDY CONCERNING THE MONITORING OF ATMOSPHERIC POLLUTION AND IMPLEMENTATION OF RECTIFICATION MEASURES
TULBURE MONICA, CIOBANU DOMNICA, IONIŢĂ IRINA
The paper research regard the system witch is aiming at the development of an informative World Wide Web (WWW) site, which through the Internet would inform the public about aspects concerning the air pollution, the evolution of the air pollution, the meteorological forecast, the air quality monitoring (in real time), the European legislation, provide advise to the public in case of severe episodes, useful phone numbers.
CONCEPT OF LIFE CYCLE ASSESMENT AND BEER INDUSTRY
TULBURE MONICA, CIOBANU DOMNICA
The overall context of the research project reported here has been to inform government policy development to reduce the environmental impacts of drink consumed, within the context of the industry sustainability strategy. The specific objectives have been to determine what evidence is available relating to the environmental impact that occurs in the life cycle of drinks. We analyze in detail the evidence available for environmental impacts that arise from the life cycles of these commonly consumed drink products.
ACT MODELLING OF THE PROPELLER WITH PALETTES FROM BUCKETS WHEAT HUMIDIFIERS
VOICU GHEORGHE, ORASANU NICOLAE, MARCU SILVIU
In this work it approaches theoretical study of the motion of the propeller with palettes from buckets wheat humidifiers considers the interactions between the particles and the palettes. Also, it proposes some theoretical relation between the parameters of work necessary to obtain the rotation angular speed of stationary regime.