Volume 3, No. 13 (2007)
Articles
PREPARATION OF C60 THIN FILM BY THERMAL VACUUM EVAPORATION
LAZĂR IULIANA, CARAMAN I., LAZĂR GABRIEL, STAMATE MARIUS, RUSU I., RUSU DRAGOS
Results of thermal vacuum evaporation method used for C60 thin films preparation are presented. Fullerene molecules were obtained by arc discharge. The deposition was made on glass, quartz, KBr and mica substrates. The influence of the sublimation temperature and substrate temperature is investigated in order to optimize the deposition, in terms of deposition rate and uniformity.
CONTRIBUTION REGARDING THE ESTABLISHMENT OF WHEAT, OAT AND BARLEY FLOUR MIXTURE TO OBTAIN DIETETIC BAKERY PRODUCTS
LEONTE MIHAI, TULBURE MONICA, CIOBANU DOMNICA
The capitalization of cereals type oat flour and barley flour, become a problem with many implication in obtaining the dietetic bakery products. The research present the influence of oat flour and barley flour about the bakery quality. An oat flour addition until 6%, in mixture with barley flour 3?6% and wheat flour type 800, can resolve the desideratum: the dietetic bakery products with improvement content of minerals and vitamins addition.
MODELING IN TIME AND FREQUENCY RESPONSE OF THE EXPERIMENTALLY DATA FROM DYNAMICAL MECHANICAL SYSTEM
LEOPA ADRIAN
In industry real situation there are the technological equipment, which works in production process with shocks and vibrations. In consequently the foundation of the technological equipment, must be hanging through a viscous-elastic system. This viscous-elastic system are designed for isolation and damping of the vibration produced by technological equipment. In this paper is presented the real situation of the production process of the forging hammer. The effects of vibration on the technological equipment and also environment will evaluate.
THEORETICAL MODELING OF DYNAMICAL BEHAVIOR OF THE TECHNOLOGICAL EQUIPMENT
LEOPA ADRIAN
This paper, presents a vision of the technological equipment dynamically behaviour, in production process activity. The press with eccentric is the technological equipment, which works with shocks and vibrations. The shocks and vibrations are sources of pollution for the environment and the technological equipment itself. In this work the level of transmitted vibrations on the environment, will be evaluated through qualitative parameters.
CONCEPTUALIZING PROJECT MANAGEMENT: FROM IMPLEMENTATION TO FINAL INTEGRATION
MACARIE FLORIN, DROB CATALIN
Success in lowering costs, bringing projects in on time and improving quality is achieved through the proper utilization of project management methodologies. An expert in project management can offer capable solutions in the areas of project management, scheduling, estimating, risk analysis, project management process development and analysis, and integration of your management information systems. The paper highlights the need of a discussion about the following fundamental issues: assumptions, levels of analysis and questions of project management research.
CERTAIN ASPECTS REGARDING THE THERMAL REGIMEN OF AXIAL-CYLINDRICAL NON-CONTACT SEALS, DESTINED FOR THE SEALING OF LIQUIDS
MANEA MITICĂ
Non-contact seals eliminate the contact between the sealed surfaces and have the effect of avoiding all disadvantages related to friction, wear and lubrication, found at mobile-contact seals. Friction inside the non-contact seal clearances is a complex phenomenon, having as consequences the thermal process of energy loss (heat) and also the wear of the clearance active surfaces. It follows that the study of the tribological behavior of non-contact seals imposes their research to be done through the approach of at least the following aspects: the development, the evolution and the consequences of the thermal regimen, respectively, the appearance, the evolution and the effects of wear.
CONSIDERATIONS REGARDING CERTAIN ASPECTS OF THE THERMAL TRANSPARENCY FOR AXIAL-CYLINDRICAL NON-CONTACT SEALS
MANEA MITICĂ
The efficiency of a non-contact seal tends towards its maximum value if its outflow rate tends towards zero. In these conditions, the hypothesis that the evacuation of heat resulted inside the axial clearance is made predominantly through the seal body/walls has been experimentally demonstrated as just. If the considerations adopted aren’t modified, one can reach the conclusion that for non-contact seals the heat evacuation is made only through its body. The methodology and analytical relations needed in the study of the thermal transparency for an axial-cylindrical non-contact seal constitutes the object of the present paper.
DAMAGE DETECTION IN WOVEN CFRP LAMINAS BY ELECTRICAL RESISTANCE MEASUREMENTS
MANTOVANI M., RIVA E., NICOLETTO G.
Fibre-reinforced polymers (FRP) are a relatively young group of materials and this leads to a gap in knowledge about properties, failure mechanisms and failure criteria. Reliable failure prediction methods are especially required for estending the range of applications. In parallel the development of non-destructive tests (NDT) for continuous health monitoring of materials would result in structures of improved durability and safety.
THE DETERMINATION OF THE STRESS IN THE SUPERFICIAL LAYERS OF Ti15Co6 OBTAINDED BBY ELECTRICAL DISCHERGE IN IMPULSE
MIHĂILESCU N., ALEXANDRU A., CHIHAI S., RACLARIU C., STRUGARU S.I.
The deposition of Til5Co6 with electrical discharge method on carbon steels is easy to make and with small expense internal stress and mosaic blocks dimensions determination is make using X-ray diffraction, in superficial layer microstructure obtained after deposition ofTH5Co6 with electrical discharge method on carbon steels. Experimental results shown the following: real width ®1, influence factors, m” and n” for mosaic blocks dimensions and respective for the internal tensions and the mosaic blocks dimensions. Superficial layers obtained using these methods confer to carbon steels bigger hardness than no sparkling carbon steel proofs. The research was made in Structural Theory Laboratories, Faculty of Science and Engineering Materials.
D`ALAMBER`S PRINCIPLE OF SOLVING ROBOT DYNAMICS BY USING MATRICES OF ROTATIONAL TRANSFORMATIONS
MIKIÆ DANILO 1, GOLUBOVIÆ DRAGAN 2
The work gives the results of the research into the D’Alamber principle of solving the robot dynamics by using the matrices of rotational transformations, i.e. the work deals with the problem of robot mechanics, and the possibilities of the application of the basic equations of matrices of rotational transformations, in solving dynamics of a robot whose basic structure is based on joints that allow only rotation. The work also lists the Dynamic Models of the manipulator that can be made based on th use of the known laws of the Newton of Lagrange mechanics. As a result of the application of these laws, there are the equations that link the effects of the forces and their moments to the segments with kinematic parameters of the movement of the chain. Also, it gives the characteristics of the movement equations of the manipulator through the Lagrange- Oiler Method, as well as the Newton- Oiler equations, and D’Alamber equations. Since the mechanical structure of a robot represents a single joint-based mechanism, a robot is seen as a disassembled chain, and then a definition is made of a geometric approach to solving D`Alamber. There is a separate account of the cases that occur in practical realisations, so that a computer program can be made for checking the validity of the solutions to the D`Alamber principle in the tasks relating to the kinematics of the robot-manipulator. The work represents a part to a project which is being realised at the Technical Faculty in Èaèak, with an aim to develop mechanotronic systems, and its results are useful in solutions related to anthropomorphic robots, as well as in other applications in various areas of technology.
THEORETICAL AND THERMOGRAPHYED THERMAL CYCLES IN POINTS AND ZONES OF WELDED JOINTS
MIRCEA OCTAVIAN, BANEA MARIANA DOINA
The paper introduces the thermal field, numerically modelled by the finite element method, and compares them to the experimentally determined data obtained by thermograph measurements. The finite element analysis was carried out. An error diagram was drawn, thus comparing the experimentally determined values to those resulted from modelling.
CAVITATION EROSION STUDY FOR DUCTILE MATERIALS
MORARU L., MURARIU G.
The paper outlines the cavitation erosion of ductile materials. Cavitation erosion studies on aluminum in ordinary tap water and degassed water are presented. The mean depth of erosion (MDE) in degassed water was higher that in tap water. The mean depth of erosion in degassed water presents a peak and than decreased continuously with time, but the maximum erosion rate in tap water in first stage of the process remained approximately constant and than starts increase. It is highlighted the tempering of the superficial layer and cavitations effects are presented as well as the appreciation parameters of cavitation destruction.
STUDY CONCERNING THE FORMS OF SOLID PARTICLES
MOŞNEUGUŢU EMILIAN FLORIN 1, NEDEFF VALENTIN 1, BĂISAN IOAN 2, PANAINTE MIRELA 1, SAVIN CARMEN 1, RISTEA MIHAI 1
An important factor for different process (the dimension or aerodynamic separation) represents the form of solid particles. In this aim different correlations were made between geometric elements of solid particle, these correlations being represented in charts. Depending on the type of used chart, solid particle will be clasificateed after their form.
INTERACTING FIELDS - A COMPLET ANALYTICAL SOLUTION
MURARIU GABRIEL
We derive the analytical solutions to the system of Klein-Gordon-Maxwell-Einstein equations for a complex scalar field minimally coupled to a spherically symmetric space-time and the feedback of gravity and electric field on the charged scalar source in a constant potential hypothesis for a particular curved space-time configuration.
ENERGY - MOMENTUM TENSOR IN CURVED SPACE - TIME
MURARIU GABRIEL, MORARU LUMINITA
The aim of this paper is to study the energy momentum tensor for scalar and electromagnetic fields for symmetric curved space-time configuration. The specific results are considered for a consecrated space –time configuration.
THEORETICAL ACHIEVEMENTS ABOUT DAMPING NON-LINEARITIES AT THE VIBRATION ISOLATION DEVICES
NASTAC SILVIU
This issue is a component of a large study, which treats the mechanical vibration problems, for the systems with dynamic non-linearity’s. Generally, it was considering both the elasticity and the damping non-linear forms, with different mathematical expressions, but the main purpose of this analysis consist by marking out of the damping characteristics on the vibration transmission or isolation at the equipments suspended on visco-elastic elements. This paper presents a set of physical and mathematical models that supposed the dependence on the viscous forces with the power series of the velocity, both with, and without its modulus. The entire approach is based on the analytical broach, with a finite number of power series terms. The partial conclusions of this study leads to the necessity of the experimental validation of the results. This approach of the non-linear visco-elastic system behavior is usable to make an initial estimation on the virtual prototype, right away the isolation system designing phase.
PRACTICAL STUDY ON ISOLATION CHARACTERISTIC FOR THE POLYGONAL SHAPE ELASTIC ISOLATION DEVICES
NASTAC SILVIU
This issue is a part of the large study performed for analyse and validate the polygonal shape elastic isolation devices (PoSEID) dynamic behaviour. Initially, it was proposed a group of elastic isolation systems, with a complex configurations - with multistairs or polygonal functional structure. The analitical analysis, completed with the experimental laboratory tests, leads to the final variant of these isolation systems to a polygonal regular shape with six visco-elastic torsional rubber elements. The main part of analysis was dedicated for analysis of these devices, from the next points of view: static and dynamic stability, functional performances, vibration isolation degree. In this paper it was presented the analitical approach of the isolation degree calculus, for a system with three degree of freedom, that was insulated on a symmetrical PoSEID configuration. The conclusions of this study was performed arround the global isolation degree values, and leads to validate the utilization of these systems on large area of applications, supposing the sensitive equipments isolation against vibrations. Finally, it is necessary to mention the fact that these devices was analysed both with virtual prototyping techniques, and with real lab experimental tests. This complex approach help to evaluate the disturbances on the designing and leads to obtaine the usable functional configuration for a doable and reliable vibration isolation system.
ADAPTABILITY STUDIES FOR A HYBRID SYSTEM PV-WIND OF SMALL CAPACITY AT THE CLIMATIC CONDITIONS FROM ROMANIA
NEGREA IONELA, DRAGUSIN GEORGIANA
The principal objectives of the project are the adaptability studies for an independent hybrid system of type Pv-Wind of small capacity till 1kw, at the climatic conditions from Romania, specially the mountain area. To do the adaptability of this system are followed some steps : the analysis and processing of meteorological data’s, taken from the meteorological station from the University; the identification type of photovoltaic panels and wind turbine possible to be used, the development, implementation and testing a concrete system. The results will be communicated in a guide for development and implementation of small hybrid systems.
THEORETICAL CONSIDERATIONS REGARDING FIRE SAFETY USING SPRINKLERS INSTALATIONS
NETCU CĂTĂLIN, PANAITESCU VALERIU
A fire sprinkler is the part of a sprinkler fire system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been reached. The paper contains theoretical aspects of modern fire security systems (sprinkler systems), aspects which can be used in order to improve sprinklers quality, reduce production costs and also, to explain the operation processes that are evolving from the moment that the temperature activates the sprinkler, in chronological order.
MATERIALS SELECTION IN BRAZING AND SOLDERING PROCESSES
OLARU IONEL, CĂLIMAN RADU
Brazing and soldering require the application of a number of scientific and engineering skills to produce joints of satisfactory quality and reliability. Brazing employs higher temperatures than soldering, but the fundamental concepts are similar, particularly with respect to metallurgy and surface chemistry. Brazing and soldering are joining processes performed at temperatures below the base material solidus temperature. To fill the joint, the liquid filler metal must spread through the joint gap by capillarity or coat the substrate by spreading.
SOME CONTRIBUTIONS ON THE MAGNETORHEOLOGICAL DAMPER ASSISTED RESEARCH
OPREAN AUREL, OLARU SERBAN, OLARU ADRIAN
The paper shown one new assisted research of the magnetorheological damper (MRD) used in the on-line optimization of the dynamic behavior of the mechanical applications. To operate with these intelligent elements was necessary to developing the proper research of some dynamic parameters and new mathematical model of the damper. The original contribution of the research was to complete the Bouc-Wen modified model with new four equations and to simulate the rheological damper characteristics. With these new research was possible to know the influence of the changed parameters to the dampers characteristics and to move some of the frequencies in to the attenuation frequency bandwidth of the Fourier spectrum. Method and the results can be used in all others mechanical research.
DETERMINATION OF GRINDING ENERGY TO VEGETABLE PRODUCT THROUGH TEXTURE ANALYSIS METHOD
PANAINTE MIRELA, NEDEFF VALENTIN, MOSNEGUTU EMILIAN, SAVIN CARMEN, MACARESCU BOGDAN, OLARU CIPRIAN
The vegetable products are visco-elastics with variable properties in time and space. The capacity of deformation of these products varies appreciably, depending of maturity degree and humidity content of products. Energy necessary to grinding these products is influenced by specie, sort as well as humidity content of products submissive to grinding. The paper presents a method from determination the grinding energy using texture analysis of vegetable products.
THE OPTIMAL ANTIFOULLING SHIP SYSTEMS
PANAITESCU FANEL-VIOREL *, PANAITESCU MARIANA *, MEHEDINTI RODICA **
In this paper are presented aspects about optimal antifouling systems. There are know that the paints which are used in ship technologies are biocides (they are contained TBT- tri-butil-toluen) and now we must used another ecological paints. By 17 September 2007, 25 States representing 38.11% of the worlds merchant shipping tonnage signed the IMO AFS Convention (also known as the TBT Convention). This means that the Convention will enter into force one year after - 17 September 2008. According to the Convention text TBT-based paint must not be applied after 1 January 2003, and by 1 January 2008 no ships must carry active TBT-based paint on their hulls.The effect of the IMO AFS Convention entering into force 17 September 2008 is: The IMO Member States that have ratified the AFS Convention will require that the necessary documentation to prove compliance with the Convention is available on board all ships irrespective of flag entering their ports.
METHODS, APPARATUS AND EQUIPMENTS TO PUT OUT FIRES
PANAITESCU VALERIU NICOLAE 1, PAVEL DRAGOŞ-IULIAN 2, POENARU MIHAI 3
In this paper are present some methods, apparatus and equipments uses to put out big fire, which can have serious influence over the environment.
RESEARCH AND MODELLING OF THE EFFICIENCY FUNCTION IN A BUSINESS SYSTEM
RADOŠ PANTIÆ 1, LJUBODRAG ÐORÐEVIÆ 2, SINIŠA JOVANOVIÆ 3
The paper presents the concept of multidimensional research work on efficiency function in a real business system based on holistic-systemic method. Under real conditions the efficiency function (d) is non-homogeneous so the paper presents it in multiparameter form, i.e. d=d (xi) based on parameters [1].
FUNCTION OPTIMIZATION OF A BUSINESS SYSTEM EFFICIENCY
PANTIÆ RADOŠ 1, TADIÆ DANIJELA 2, ÐURIÈIÆ MILUTIN 2
The paper presents analytical and experimental method of optimization (Box-Wilson`s gradient method) obtained during researching the function parameters of a business system efficiency.
EXERGO- ECONOMIC ANALYSIS OF AIR POLLUTION FROM POWER PLANTS
PARASCHIV SIMONA LIZICA, PARASCHIV SPIRU
The benefits of air pollution control techniques on a power plant are simulated with a scientifically based environmental model. Air pollution abatement techniques are assessed in terms of their resource cost (measured in dollars) and their effectiveness in reducing environmental damage (measured in dollars and healthy days lost). Which air pollution techniques are most efficient depend upon how much a day of health should be valued.
ENVIRONMENTAL BENEFITS OF USING PARABOLIC TROUGH IN SOLAR THERMAL POWER PLANTS
PARASCHIV SPIRU, PARASCHIV SIMONA LIZICA
Concentrating solar power (CSP) to generate bulk electricity is one of the technologies best suited to helping to mitigate climate change in an affordable way, as well as reducing the consumption of fossil fuels. Life-cycle assessment of the emissions produced, together with the land surface impacts of CSP systems, shows that they are ideally suited to the task of reducing greenhouse gases and other pollutants, without creating other environmental risks or contamination. Each square meter of CSP concentrator surface, for example, is enough to avoid annual emissions of 200 to 300 kilograms (kg) of carbon dioxide, depending on its configuration. Most of the CSP solar field materials can be recycled and used again for further plants.
SIMULATION AND ANALYSIS OF CONTAINER TERMINALS OPERATIONS – CASE STUDY: KOREAN PORTS
NAM KYU PARK 1, BRANISLAV DRAGOVIÆ 2, ROMEO MEŠTROVIÆ 3, JU-YOUNG KIM 4
This paper aims to determine terminal performance and to calculate optimal throughput of a quay by port type. To this end, we have collected data, processed them, and inputted to the developed simulation model. The three port types of new port are considered to be typical of the future ports under construction or to be construction soon. The optimal throughput calculation of quay, the required number of cranes, and optimal berth occupancy can be given by using the simulation models of this study. The existing calculation methods of optimal throughput of a container terminal have mainly been based the berth capacity alone. Because of this, the container handling volume over the design capacity has rapidly worsened the traffic congestion of CY. The high density of CY worsens not only the productivity of a container terminal, but also increases sharply its logistics costs by forcing some cargoes into the ODCY. According to the questionnaire survey centring on the opinions of veteran terminal operators, the CY occupancy ratio of 60% is suitable for smooth workflow of the whole container terminal. Based on this idea, if the logistics volume is generally maintained at the level of CY occupancy of 60%, it will be reasonable and productive.
A FEA APPROACH TO SIMULATE THE DYNAMICAL BEHAVIOUR OF A COMPLIANT MECHANICAL STRUCTURE
PELE ALEXANDRU-VIOREL, BABAN MARIUS, BABAN CĂLIN FLORIN, BLAGA FLORIN SANDU
As opposed to rigid-body mechanisms, the structural elements of a compliant mechanism utilizes their elastic characteristic to generate a specifying mobility on the predetermined portion, or to delivers the desired motion and force by undergoing elastic deformation. Even the mechanical structure is designed and built as a rigid one, often the entire structure has a compliant comportment resulting from elastic deformations of links, elasticity of joints, dumping elements etc. Numerical simulation of mechanical response of such structure can be formulated using finite element method. In this paper a method to determine dynamical response of a compliant planar mechanism is proposed.
SMOKE AND HEAT EXHAUST VENTILATION SYSTEMS IN ATRIUM BUILDINGS
PETCANA CĂTĂLIN 1, PANAITESCU VALERIU 1
Almost people hurt or die because of heavy smoke when the building fires. This is the reason that the current codes in many countries require that the smoke layer in an atrium be maintained above the highest means of egress in the space. The smoke exhaust capacity needed to maintain the smoke layer above the highest level of the means of egress can be substantial if that level is near the top of a tall atrium. In spite of this, there are a number of situations that may affect the effectiveness of a mechanical exhaust system used for atrium smoke management and make this problem to become a real puzzle.
STUDY REGARDING USING POSITIVE PRESSURE VENTILATION IN CASE OF FIRES
POPA CONSTANTIN *, PANAITESCU VALERIU **
In high buildings fires, most of the casualties are situated at the top floors - asphyxiated because of the smoke and hot gases - although the fire occurred at a lower floor. The smoke and hot gases travel from one floor to another mainly using the stair shaft. If this stair shaft would be pressurized, then the people at the top floors will be able to use the stairs for evacuation, as smoke and hot gases will find other way to dissipate. The research below uses a fire modeling on a high building, to assess and approximate the influence of positive pressure ventilation.
THE MODERNIZATION OF THE KINEMATIC CHAIN OF THE THERMOREGULATOR T 5N FOR THE AUTOMATIC INTERLOCKING OF THE ELECTRIC CONTACT AT POSITIVE TEMPERATURE
POPESCU GHEORGHE * POPESCU HENRIETA LUIZA **
This paper presents the results of the researches overtaken by the authors for the achievement of a thermoregulator fit for controlling the automatic thawing of the freezing chamber. By the modification of the kinematic chart and by the joint use of a cam and an adjustement temper screw, it was attained the getting of a constant interlocking temperature whereas the cutting-out and the differential temperature are variable.
EXPERIMENTAL RESEARCHES REGARDING THE ACHIEVEMENT OF A PROTECTION VALVE WITH CORRUGATED PIPE FOR GAS FURNACES
GHEORGHE POPESCU, GHIMIŞI ŞTEFAN, ALIN STĂNCIOIU
In this work the authors present the results of their own researches regarding the achievement of a protection valve with corrugated pipe for gas furnaces. The valve with corrugated pipe was conceived in a way that in case of random disconnection of the gas blowpipe flame it couples out automatically the gas and a new firing could not be attained without human intervention. The valve was conceived for gas blowpipe with low yield usable at the refrigerating systems (type Fram 22) for vehicles.
ABSORPTION SPECTERS OF NARROW GAP SEMIMAGNETIC SEMICONDUCTORS WITH COMPARED WITH NONMAGNETIC SEMICONDUCTORS
POSTOLACHI IGOR
In present work were studied the main laws of components repartition on the epitaxial coats geometry of Hg1-xMnxTe, Hg1-xCdxTe and Hg1-x-yCdxMnyTe using two methods: the micro-X-ray-structural method and the optic methods. A curve of standardization was constructed, having from the experiment the energy band width to determine the concentration of cadmium and manganese. Analyzing the absorption specters structure it was determined that in the absence of external magnetic field the energy specters of the charge carriers of the semimagnetic materials Hg1-xMnxTe, Hg1-x-yCdxMnyTe and of nonmagnetic materials Hg1-xCdxTe with the same energy gap width have the same form. The theoretical calculations of absorption specters were realized within the Kane model with its non-parabolic perturbations specific for indium antimonid as the narrow-gap semiconductor.
PRESENT AND FUTURE IN EFFICIENCY
POSTOLICĂ VASILE
This research work is concerned with the usual concepts of the Efficiency and Optimization. After a short Introduction, we give some questions on the notion of the Efficiency and we emphasize the Pareto Optimality as one of the illustrative examples.We present the Efficiency and the Optimization in the Infinite Dimensional Ordered Vector Spaces following also our recent results concerning the most general concept of Approximate Efficiency, as a natural generalization of the Efficiency, with implications and applications in Vector Optimization and the new important extension of our Coincidence Result between the Efficient Points Sets and the Choquet Boundaries. In this way, the Efficiency is connected for the first time with Potential Theory through the agency of Optimization and conversely. Several pertinent references conclude the study.
RESEARCHES IN MODULAR ROBOTS KINEMATICS
POZNA CLAUDIU, ALEXANDRU CĂTĂLIN
Present paper describes one part of the kinematical researches made in modular robotic field. The aim of these researches is to generalize the homogenous formalism. This generalization is need in the modular robotic field because of the multiple possible configurations. The modularity is view like a customer, and not producer, possibility to build robots for particular needs. This is the reason that in order to implement the mentioned modularity concept we need tool which allow to a task specialist (the customer) to design robots.
ABRASIVE WATERJET CUTTING
RADOVANOVIC MIROSLAV
Cutting plate is a difficult and time consuming task, especially when the job calls for a tight tolerance or an unusual shape. In those cases, can choose abrasive waterjet cutting. Abrasive waterjet cutting is an attractive process with many advantages. For efficient application abrasive waterjet cutting it is necessarily to define cutting data, especially cutting speed. High levels of contour precision at precisely defined cutting speed have an important effect on the quality of the cut. This paper gives results of the research referring to the determination of principal parameters by abrasive waterjet cutting. Cutting with waterjet costs less than traditional machining or other cutting methods. Waterjet is now the most cost effective method to cut steels. The cost ranges provide a basis for an cost estimation prior to plan of buying order of waterjet machine. The cost analysis of abrasive waterjet cutting is also presented in this paper.
STUDIES REGARDING THE SORPTION OF NITROSO R-SALT ON PUROLITE A 600-PL RESIN - Part I
RADULESCU EUGEN *, STANCIU CONSTANTIN *, CANTEMIR GHEORGHE *
The paper presents some peculiar aspects of ion exchange behaviour for a strongly basic anion exchange and a sulphonic chelating agent. A potential chelating resin was prepared from a common strongly basic anion-exchange resin used in a water demineralization plant, PUROLITE A600-PL, by treatment with Nitroso R-Salt (NRS). The effect of stirring regime, phase contact time and initial concentration on sorption capacity of ion exchange resin and sorption mechanism have been investigated. The dynamic capacity of resin loaded with NRS was found to be 1.45 mmol NRS /g dry resin.
STUDY REGARDING BIOLOGICAL CONTAMINATION OF SOIL WITH MUNICIPAL SOLID WASTES
RUSU LACRAMIOARA 1, TOPLICEANU LILIANA 1, HARJA MARIA 2, DABIJA ADRIANA 1
The municipal solid waste represent an actual problem as through the quantity and diversity of them and through a danger for environment and population healthy. This paper presents a study regarding biological contamination of soil around waste dump from Bacau. For determinate of soil contamination was effectuated a series of experiments were cropped and analyzed soil samples at different distances and depths of waste dump. For the obtained results the conclusions are : a significant pollution of the soil at 500 m distance at 0-10 cm and 10-20 cm depth, a decrease of total number of germs at 1000 m distance. Effectuated study has permitted the establishment a pollution causes, a impact an environment and the measures that needed in order to reduce pollution.
IMPLEMENTATION OF SUSTAINABLE DEVELOPMENT CONCEPT IN ROMANIA
RUSU TIBERIU
The paper presents the evolution of the sustainable developing concept considering global and local fields. It is also presents the main actions realized in Romania for the implementation of this concept in to economical and industrial evolution and environment protection.
EXPERIMENTAL RESEARCHES CONCERNING THE CAVITATION IN CASE OF MIXTURES BY TYPE LIQUID-LIQUID (L-L)
SAVIN CARMEN, NEDEFF VALENTIN, ZICHIL VALENTIN, PANAINTE MIRELA, MOŞNEGUŢU EMILIAN, AMBĂRUŞ ALEXANDRU IRINEL
In this paper it was realized an experimental study about cavitation appearance conditions to obtain a mixture by type liquid-liquid (L-L). The experiences was done, in function of: the nature of the phases into mixing operation (water-water), the geometrical shape and the geometrical dimensions of the mixing device and the mixing vessel, the highness of the mixing device into the mixture’s mass.
THE ORIENTATION OF THE “RANGE MATRIX” IN MATHEMATICAL MODEL OF THE QUATERNIONS FOR A RTR ROBOT
SAVUC GABRIELA 1, FLORESCU DANIELA 2, STANCU MIHAI 1
The paper presented a stochastic model for the matrix used in determinations for the Denavit-Hartenberg parameters by means of quaternion method for an RTR slewing bracket.
THEORETICAL STUDY ABOUT THE DETERMINATION OF THE ANGULAR SPEED FOR A RTRTR ROBOT USING THE QUATERNION METHOD
SAVUC GABRIELA 1, FLORESCU DANIELA 2, STANCU MIHAI 1
This present paper studies the determination of the rotational speed for an RTRTR robot using the quaternion method.
SOME CONSIDERATIONS REGARDING DYNAMIC STRESS INTENSITY FACTOR DETERMINATION USING A THREE POINTS BEND ANALITYCAL METHOD
SECHEI RAMONA
This paper presents some considerations regarding dynamic stress intensity factor determination using a three point’s bends analytical method. This method is based on a double mass-spring system. In this system the specimen and the striker are both represented as mass-spring system. The specimen stiffness is computed using the midspan deflection of the beam and the contact stiffness is computed using a linear force-deformation relation.
SOME ASPECTS OF HEAT TRANSFER FROM THE CAST TO THE MOULD
SIMIONESCU GHEORGHE, CIUCESCU DORU
In the foundries is very important to understand and to control the transfer of the heat from the cast to the surface of the mould. This paper is an attempt to present some aspects concerning the transfer of the heat from the cast to the surface of the mould when appears a clearance or not.
SOME ASPECTS CONCERNING THE PHYSICAL PHENOMENA AT THE CONTACT ALLOY – SAND MOULD
SIMIONESCU GHEORGHE, CIUCESCU DORU
In the foundries is very important to understand and to control the physical phenomena at the contact alloy – mould. One very important phenomen is the expansion of the sand mould. This paper is an attempt to present some aspects concerning the physical phenomena at the contact alloy – sand mould under the influence of the temperature.
RESEARCH CONCERNING DETERMINATION OF SPECIFIC POLLUTANTS IN WASTE WATER DISCHARGED FROM THE PULP MAKING
STANCIU CONSTANTIN, CANTEMIR GHEORGHE
:In the pulp making processes, organic and mineral compounds are released in waste water discharged from different process stages. The paper shows the research carried out to set the types of pollutants specific to chemical and paper pulp making. The content in suspensions, CODCr, BOD5, pH, fixed residue and its content of organic substances, the content of sulphates, sulphites, ammonia nitrogen and chlorides were determined on process stages and values of pollution indices were calculated (kg pollutant/t pulp). In both production processes, the effluent with the highest load is from cooking-washing due to losses of waste liquors and non-recovery of lignosulphonic draff.
FLOCCULATION – MECHANISM AND USE IN PAPER INDUSTRY
STANCIU CONSTANTIN **, GRAVILA LUCIAN *, CANTEMIR GHEORGHE *
The efficiency of solid/liquid separation may be improved significantly by using synthetic polymers as flocculation aids. Flocculation may be caused by the interparticle collision or by reducing the particle electric load. This paper presents the synthetic flocculation aids having the role of blocking (cationic and anionic polyacrylamides), action mechanism, factors affecting flocculation (charge, effect of shear, effect of particle size, effect of stock consistency, effect of polymer molecular weight, effect of pH, effect of temperature and charging place). The experimental part shows the effect of using some cationic and anionic polyacrylamides in the paper making process. Improvement of physico-mechanical and optical paper properties as well as reduction of suspensions in waste water by over 50% are noticed.
THE ECONOMY OF MINERAL RESOURCES IN THE CONTEXT OF SUSTAINABLE DEVELOPMENT
STOICA MARICICA 1, MANEA GHEORGHE 2
The authors present in the paper the mineral resources identified on the territory of Bacau County, in the first phase of research of the project “Research on a systemic approach of sustainable development at administrative-territorial level” and proposals for their sustainable valorization through technologies available in international practices. The paper presents proposals of ecological reconstruction of run-down sites, as well as ways of inclusion in the economic circuit of certain yet unexploited resources, the valorization of the latter offering ecological products in demand on the domestic and international markets on the channel of sustainable valorization of resources.
MANAGEMENT OF THE ECOLOGICAL RECONSTRUCTION OF URBAN HABITATS (CASE STUDY BACAU COUNTY)
STOICA MARICICA
Bacau County is rich in mineral resources but is polluted, by a historic pollution due to mining and manufacturing industry; over the last years it was increased by heavy road traffic and the spatial, not rigorously planned, expansion of cities. The paper presents the ecological state of the county’s cities, an evaluation carried out in the first phase of the research-project “Research on a systemic approach of sustainable development at administrative-territorial level” and based on the proposals concerning ecological reconstruction, namely: increasing urban metabolism through recycling and re-use of domestic waste, reducing air, water soil and phonic pollution, an integrated management of natural and antropic risks on the whole territory of the county.
SPRINKLERS & FIRE VENTING – CONTROVERSY RESOLVED
SUSAN OLEG 1, PANAITESCU VALERIU 2
Resume: The studies of smoke and heat venting used in conjunction with sprinklers show clearly that venting does not have a negative effect on sprinkler performance. Successful performance of sprinklers does not rely upon reduced oxygen concentrations. Venting has been shown to have no effect on the activation times of early sprinklers and does not affect the total number of sprinklers activated. If the fire is directly beneath a vent, activations of the first sprinklers may be delayed slightly, but there is no evidence that this will have a significant impact on sprinkler performance.
ANNEALING EFFECT ON THE PHYSICAL PROPERTIES OF SB2S3 THIN FILMS
TIGAU NICOLAE
Uniform, adherent and reproducible antimony trisulfide (Sb2S3) thin films have been deposited on glass substrates maintained at room temperature, using thermal evaporation technique under vacuum. The effect of annealing on the physical on the crystal structure, surface morphology and optical properties of Sb2S3 thin films has been studied. The structural analysis from transmission electron microscopy showed that the as-deposited films were amorphous in structure and annealed films at 500 K become polycrystalline with orthorhombic structure. The effect of the annealing temperature on the dispersion of refractive index of the as-deposited films was investigated and analyzed within the single oscillator model.
SB2O3 THIN FILMS DEPOSITED BY THERMAL EVAPORATION TECHNIQUE
TIGAU NICOLAE
Antimony trioxide (Sb2O3) thin films were prepared by thermal evaporation under vacuum technique, using Sb2O3 powder as evaporate onto glass substrates. The substrate temperature was varied from 323 to 473 K and structural and optical properties of the films were studied. The structural studies of the Sb2O3 thin films indicates the presence of the ?- Sb2O3 with predominant cubic phase. The energy band gap of Sb2O3 thin films was determined from the absolute values of the measured transmittance by assuming a direct transition between valence and conduction band of Sb2O3 thin films.
STUDY REGARDING ELECTRO-HYDRAULIC LOAD-SENSING SYSTEMS
TIŢA IRINA
The paper describes the structure and the mathematical model for a load-sensing system having in view the effects of a simplified analysis (neglecting the flow dynamic effects). The proposed model helps us to see the way to improve the energy balance of the system and how to introduce a load-sensing loop.
ANALYSIS OF MAINTENANCE PRACTICES ADOPTED BY THE ROMANIAN PRODUCTION SYTEMS
TOMA VICTORIA, MĂRĂSCU-KLEIN VLADIMIR
In the present globalization stage, there are a lot of constraints of productive systems (costs, complying with terms, quality, health and environmental security, etc) which became sharper. By its specific and complexity, the maintenance activity of technical equipment has a significant influence on the efficiency of production system. Various studies and researches carried out in different countries, point this out. With this respect, this paper proposes to ground designing of a questionnaire, intended to carry out a research of maintenance practices existing within Romanian production systems, especially IMM-s (Small and medium sized companies). Among the objectives of the questionnaire are: to identify and check variables, their interconnection having as aim the formulation of some improvement proposals.
REVERSE VELOCITY PARAMETER OF VALVES
TOPLICEANU LILIANA
The main objective of this paper is to discuss the valve and pipe characteristics which affect the reverse velocities and pressure surges at the check valves. It is presented a test method by which check valves can be dynamically tested for sudden closure due to reverse flow. It is point out the influence of valve design, flow coefficient, and friction of the reverse velocity. The information developed from the test method can then be used to predict the resulting upstream and downstream transients or pressure surges caused by a check valve closure for a given piping system and flow deceleration. The test method of this paper produces a relationship between the flow deceleration and the reverse velocity at which the check valve closes.
SOLUTION FOR THE PROBLEM OF HYDRAULIC POSITION CONTROL IN CASE OF NONLINEARITY
TOPLICEANU LILIANA
The paper presents a solution for control of hydraulic position problem in case of servomechanism, by using a sliding model control with a fuzzy boundary layer. A nonlinear hydraulic servomechanism which has an asymmetric cylinder is modeled and simulated first, and then the proposed control scheme is applied to this model versus the conventional sliding mode control. Simulation results proved that the chattering free position control is achieved by tuning the fuzzy scaling factors properly.
DECREASE OF THE PRESSURE LOSS IN TRANSPORT OF VISCOUS FLUIDS
TOPLICEANU LILIANA, RUSU LACRAMIOARA
The problem of pressure loss by friction in pipelines, especially in the case of viscous fluids, has a great influence of the efficiency of the technologic process. The paper discuss two main methods for reducing the frictional pressure loss, and therefore the pump discharge pressure requirement, when transporting viscous, often non-Newtonian, slurries and pastes in pipelines. The first method makes use of boundary liquid (such as water, oil, or polymer solution) which is injected at comparatively small flow rates into the pipe downstream from the pump to form a lubricating annulus adjacent to the pipe wall. The second method involves gas injection into the pipe downstream from the pump to form a slug flow pattern which results in substantial frictional pressure loss reductions for shear-thinning, non-Newtonian slurry, initially flowing in the laminar flow regime prior to gas injection.
ATMOSPHERIC AIR POLLUTION EMISSIONS
TULBURE MONICA, DOMNICA CIOBANU, IONIŢĂ IRINA
Air pollution modelling serves to relate air quality to emissions in a quantitative sense, and provides a better basis for describing areas of exceedance in the entire zone. It also provides additional essential information for the management of the air quality in the zone, as required under the FWD. All three methods or tools provide information with inherent uncertainty. By uncertainty we mean a quantitative measure of the most likely possible deviation of the value from the true value. See the text box below which defines some relevant concepts in this context. Measurements — apart from sampling and analysis errors - may introduce major uncertainties if stations are not representative, meaning that air quality in the surroundings differs substantially from air quality at the station, or that concentrations vary appreciably in time while the measurements have only limited time coverage. Emission inventories can be incomplete or may be based on inaccurate or inappropriate emission factors or activity figures.
APPLICABLE METHODS FOR THE EVALUATION OF IMPACT ABOUT THE CONDITIONS UTILIZATION OF THE WASTE IN THE MANUFACTURE CARDBOARD
TULBURE MONICA, NEDELCU MIRELA, CIOBANU DOMNICA
Which conclusions can fire at abaft implementation of studious methods for the quantification impact about average, activity of remake the waste: impact about the above-ground water is negative, positive influences shall appear just through the modernization reprocess the installation of remake the waste and the station of purging the worn-out reduced, the addition of waste in the composition of the paste of paper; The platforms of store the residues results from waste as well as the mud are due to corresponds the ecologic requirements, so that to is avoided the transport of to the pluvial waters pollutant compounds have these residues; the factors of average: Soil, air and human placements affected by-paths in special of the inadequate storage solid residues and the mud results from the activity of remake the waste.
BIOLOGICAL WASTE TREATMENT – COMPOSTING IN ENCAPSULATED SYSTEMS (BAY, BOX, TUNNEL, INVESSEL COMPOSTING)
TULBURE MONICA, IONIŢĂ IRINA, DOMNICA CIOBANU
Composting in encapsulated systems follows the general objectives of open windrow composting but with the advantage of : accelerating the rotting process (and thus increase throughput/save space), improving process control and thus product quality, and taking better control over emissions and thus reduce potential nuisances. Composting is an aerobic process that by definition requires oxygen and biologically degrades/converts organic material to CO2, water and humic substances. Composting in encapsulated systems means the composting of biodegradable waste in a closed reactor with minimized thermal exchange with the atmosphere and relies on various methods of aeration and mechanical turning to control the process. These mechanical systems are designed to minimize odors and process time by controlling airflow, temperature, and oxygen concentration. Closed systems make it possible to collect gaseous emissions, odors and particulates. The active aeration, watering and mixing functions enable control and optimization of the rotting process, thus considerably accelerating the main biodegradation phase. Composting in encapsulated systems is more strictly divided into a prerotting and a secondary rotting or maturing stage. Proteins represent 90-95% and include albumins, globulins 30%, gliadin soluble in alcohol 70% and a reduced content of glutenin. Ovenina, the gliadin of oats not form gluten with glutenin and has poor bakery properties. Starch is in top of glucides. Minerals are not distributed uniformly in bean. Oats flour contains vitamins B, PP and enzymes.
RESEARCH CONCERNING THE IMPROVEMENT OF THE MAGNETRON OPERATION WHEN VARIABLE POWER LEVELS ARE REQUIRED
URSU MIRCEA-PETRU, BUIDOŞ TRAIAN, ALEXANDRU-VIOREL PELE
There are a several microwave applications (ex. medical diathermy) which require small power magnetrons; these magnetrons are very expensive, because they are produced in very small quantities. This paper shows how the output microwave power of a given magnetron can be adjusted, according to the required power for the appliance.
ASPECTS REGARDING WHEAT WETTING BEFORE GRINDING USING THE MECHANIC HUMIDIFIER WITH CURBED PIPES
VOICU GHEORGHE, MARCU SILVIU
The paper presents some aspects regarding construction and the working process of a mechanic humidifier with curbed pipes, a calculus regarding water consumption as function of seed flow for arriving from the storage moisture to the primary milling stage humidity. Based on connection between this parameters it was graphically represented the variation of water flow for seeds wetting at different initial moisture contents of seeds with the purpose to arrive at a final moisture content of 15.5%, respectively 16.5%. Aspects presented in this paper are useful for designers and manufactures of seeds humidifiers but especially for users of such equipments.
MATHEMATICAL MODEL FOR THE DETERMINATION OF THE NECESSARY DRIVE POWER OF THE RADIAL BLADES MIXERS
VOICU GHEORGHE *, ENE GHEORGHE *, NICOLESCU MIHAI **
This paper presents a mathematical model for the calculus of the necessary shifting power of the radial blades mixers for solid granular products. For the radial blades inclined up to the rotor rotation axis they are writing the relations of the material particles speed, axial and tangential, for the case when it is neglected the friction and for the case with friction, also the resistance forces at moving material on the two considered directions. It is writing the general relation for the calculus of the shifting power and it is ratifying the mathematical model through illustration on an available radial blades mixer.
ADAPTIVE HIPERMEDIA SYSTEMS IN E-LEARNING
DAŠIÆ PREDRAG 1, NEDEFF VALENTIN 2, ŠEHOVIÆ SEFEDIN 3
E-Learning is application of modern informational technologies (IT), as such: Internet and Web technologies, software for modern education, Hi-tech and mobile classrooms, video projectors, digital tables etc. in process of learning. Adaptive Hypermedia Systems (AHS) are almost always based on some Artificial Intelligence (AI) technologies. In paper is given an explanation of e-learning and adaptive hypermedia systems (AHS).