Volume 2, No. 13 (2007)
Articles
ON THE HEAT TRANSFER IN NANOFLUIDS
AGOP MARICEL 14, VIZUREANU PETRICĂ 2, NICA PETRU 1, ENACHE VLAD 3
Using the fractal space-time theory (scale relativity theory), the dynamics of the fluid/nano-particle interface was analyzed. In the general case, the heat transfer through the interface reproduces a d.c. or an a.c. Josephson effects of thermal type, while in the linear approximation, the standard form of heat transfer is given. Consequently, a negative differential thermal conductance appears and an increasing of the heat transfer in nanofluids results.
CONCEPT REGARDING OPTIMAL-ADAPTIVE GOVERNING OF CUTTING PROCESS
ALAMANO ANA MARIA *, HAUK NICULAI **, EPUREANU ALEXANDRU **
This paper present an algorithm of optimal-adaptive governing of dressing process based on “on-line” reidentification taking as an optimization criteria the profitability rate. Thus, the optimization of dressing process is depending on market success of the machined product. Starting with those concepts it have been realized an informatic product for experimental implementation of optimal-adaptive governing of cutting process. It is shown the behavior of the numerical programme in different working situations.
DYNAMIC ANALYSIS OF THE PHOTOVOLTAIC TRACKING SYSTEMS IN MECHATRONIC CONCEPT
ALEXANDRU CĂTĂLIN, POZNA CLAUDIU
The paper presents researches in the field of increasing the efficiency of the photovoltaic systems. The idea is to design a tracking system that changes the position of the photovoltaic panel in order to maximize the solar radiation degree of use. The tracking system is approached in mechatronic concept, integrating the control system in the mechanical model. The analysis is made using a virtual prototyping platform that includes the following software: CATIA, ADAMS/View & Controls and MATLAB/Simulink. The behavior of the tracking system is evaluated from energetic efficiency point of view.
WINDSHIELD WIPER MECHANISMS DESIGN IN MECHATRONIC CONCEPT
ALEXANDRU CĂTĂLIN, POZNA CLAUDIU
Determining the real behavior of the windshield wiper mechanisms is a priority in the design stage since the emergence of the computer graphic simulation. The paper attempts to analyze and simulate the windshield wiper mechanisms by using a complex virtual prototyping platform, which includes the following software: CATIA (realizing the 3D solid model), ADAMS/View (analyzing and optimizing the mechanical model), and ADAMS/Controls & MATLAB/Simulink (controlling the mechanism). For applying the design strategy, we considered a tandem pattern double-lever system, which is approached in the concurrent engineering concept, by integrating the control system in the mechanical model at the virtual prototype level.
CRITERIA FOR COMPARATIVE ANALYSIS OF STEEL GRADES WITH CRACK AVAILABILITY IN CONDITIONS OF STATIC LOADING
ANGELOV IVAN, ZHELEZAROVA DANIELA
In this paper methodologies for assessing the reaction of metal with crack availability in conditions of static loading have been composed and the corresponding criteria for comparative analysis of steel grades have been obtained as well about evaluation of their serviceability when defect is available.
LIFTING MANIPULATORS FOR GARBAGES
ANTONESCU OVIDIU *, ANTONESCU PAUN **, MIHALACHE DANIELA ***
Abstract - The paper begins with a short history of development on the recycling and waste gathering vehicles since the First World War. The lifting and getting off the bins, to and from the body of special waste trucks, by some planar linkage – manipulators are studied. These lifting manipulators are equipped with gripper systems in order to load and unload the bins. Several kinematical schemas of type mono– and bi-mobile manipulators are analyzed, these being driven by one or two linear actuators. The kinematical geometry of these planar manipulators by means of scale drawing of the kinematical schema is displayed. Both lifting and getting off phases of waste bins were considered. Two solutions for a better efficiency and a green environment have been proposed. The second one is using an electric powered driving transmission. Finally, a modeling and simulation case of the lifting manipulator is presented.
GEOMETRICAL SYNTHESIS OF MECHANISMS USED FOR MANOEUVRING OF WINDOWS ON CAR SIDE DOORS
ANTONESCU PĂUN *, ANTONESCU OVIDIU **, MIHALACHE DANIELA ***
The paper presents the method of the geometrical and kinematical synthesis of the mechanisms which are used for opening / closing of the windows the automobile side doors. For geometrical synthesis, more kynematic diagrams of four-bar linkages are considered. As special mechanisms, there are synthesized the Chebyshev’s mechanism, the Evans’ mechanism and parallel-crank mechanism.
MESOSCOPIC STRAINS IN WOVEN CFRP COMPOSITES: COMPARISON OF DIC VS. FEM RESULTS
ANZELOTTI G., NICOLETTO G., RIVA E.
The mechanics of woven carbon-fiber reinforced plastic (CFRP) composites is influenced by the complex architecture of the reinforcement phase. Computational (i.e. finite element based) approaches have been used increasingly to model not only the global laminate stiffness, but also damage evolution and laminate strength. The modeling combines the identification of the architectural unit cell UC, the selection of suitable constitutive models of the different phases, the creation of a fine discretization of the UC in finite elements, the application of an incremental solution procedure that solves iteratively for the stresses and strains in the UC, [1].
RESEARCHES REGARDING THE INFLUNCE OF SODIUM CHLORIDE ADDITION ON QUALITY OF TOMATO PASTE
ARUŞ VASILICA ALISA, VARTOLOMEI NICOLETA
Among the products obtained from tomato, the tomato paste, takes the first place in manufacturing industry of tomato paste. The tomato paste has a high nutritive value as a result of glucide content, C vitamin, carotene and mineral salts. The researches from this study in the domain of tomato products are based on the influence of sodium chloride addition on quality of the tomato paste.
KINEMATICAL ANALYSIS OF CYLINDRICAL GEAR MECHANISMS
ATANASIU MIHAIL, FILIP VIVIANA
The paper presents the method of independent cycles used for kinematical analysis of cylindrical gear mechanisms. This method needs firstly the graph elaboration and after it needs the equations of velocities for each independent cycle. The method can be usually used in computational algorithms and it is easily for planetary gears mechanisms calculus, in comparison with classical Kutzbach and Willis methods.
SOME ASPECTS CONCERNING MATERIALS AND THEIR IMPORTANCE IN THE ECO-DESIGNCONCEPT
AXINTE CRINA1, CRISTEA I.2, KOLIOPOULOS T. C. 3
In this paper certain properties of some common materials are presented. The aim is to show typical issues of these materials for a general understanding of what should be kept in mind when using them and setting targets for manufacturing environmental friendly products.
ECOLOGICAL RECONSTRUCTION OF THE TROTUS BASIN (CASE STUDY BACAU COUNTY)
BERCA MIHAI 1, STOICA MARICICA 2
The area of the Trotus basin is of 4,456 km2, of which at least 20% is in need of antropic interventions, as the ecologically areas affected by erosions and transports are continually increasing. Therefore the issue is the ecological reconstruction of about 900 km2 = 90,000 ha. The length of the Trotus river is of 162 km, of which about 130 km in Bacau County. This length (river section) requires special works of water-bed and streamline regulation and ecological renewal of the affected flood-planes and terraces (15,000ha). Areas of forest clearings that have to be replanted represent about 70,000 ha, in order to complete forested areas, and without having the guarantee that this would solve the dramatic issue of floods. The catastrophic floods of 2005 were the synergetic outcome of thermo-climate deregulations due to the pollution of the stratosphere by toxic gases and the massive antropic degradation related mainly to the clearings in the Trotus basin.
WELDING OF STAINLESS STEEL USED FOR THE MANUFACTURE OF HYDRAULIC VALVES
BESNEA DANIEL, DONTU OCTAVIAN, ALEXANDRESCU NICOLAE
The paper presents the results of the experimental research regarding the microwelding of stainless steel by pulsed Nd :YAG laser. The analytical and experimental investigation on laser weld ability of a stainless steel allowed to draw the following conclusions. The micro-welds produced by the optimized Nd: YAG laser parameters featured a narrow and regular weld metal zone devoid of any solidification and shrinkage defects.
THEORETICAL RESEARCH CONCERNING OF DEFLECTIONS FOR HORIZONTAL SHAFT OF MIXING DEVICES
BIBIRE LUMINITA, COBREA CODRIN
The classic calculation (for dynamic conditions) on deflections of mixing devices shafts (in horizontal position), is, generally, done with assumption that important factors (gyroscopic moment, axial force and torque) are neglected. For this reason, a certain discrepancy between theoretical and practical results exists. The paper presents a methodology calculation of shaft deflection, considering the all these factors (gyroscopic moment, axial force, torque), which are usually neglected.
EXPERIMENTAL RESEARCHES ON THE INFLUENCE OF THE SEALING BOX ON THE DEFLECTIONS OF THE MIXING DEVICE SHAFT
BIBIRE LUMINITA, COBREA CODRIN
The aim of the paper is to confirm in a practical way the theoretical result which were presented in a paper named Theoretical researches of the sealing box influence on the deflections of mixing devices shafts by the same author. The paper presents the experimental installation, measurement system and experimental.
CALCULUS OUTLINES FOR THE FALLING-FILM EVAPORATOR USED IN THE SUGAR INDUSTRY
BIRIŞ SORIN 1), DRAGOMIR MARIA 1), PANAINTE MIRELA 2)
The concentration (the vaporization) is the technological operation by Concentration is the technological operation by which the amount of dry substance is increased by partial elimination of a water from the diffusion juice and their transformation in the concentrated syrup by providing the necessary thermal energy (of the boiling heat of the vaporization) [4]. In other words, the vaporization is a thermal transfer operation by which a liquid reach the vaporous state, elimination and the concentration of the making steams [4].
PROCESS OF STRATEGIC MANAGEMENT IN THE COMPANY
BISERKA NOVAKOVIÆ RAJÈIÆ, MARKO CARIÆ
Strategic management is regarded as a process within which managers, having in mind all available circumstances in the environment and the company itself, formulate and carry on strategies to reach optimal strategic aims. The process of strategic management comprises several main components as illustrated on Fig. 1
THERMOECONOMIC OPTIMIZATION OF THE ENERGETIC PLANT WITH INTERNAL COMBUSTION ENGINES BY USING STOCHASTIC PROGRAMMING METHODS
CARAGHIULEA MARIANA
In this paper is presented a wording of the thermoeconomic optimization of the energetic plants with internal combustion engines and the consideration of some stochastic independent variables by using stochastic process optimization methods since the design phase.
THE TECHNIQUE OF MEASUREMENT OF MODULATED OPTICAL SPECTRA
CARAMAN IULIANA, STAMATE MARIUS, CARAMAN MIHAIL, RUSU DRAGOS
In the lust two decades the researchers pay attention to the optical properties of semiconductor layers which are used in different electronic devices. The special role of these investigations has the study of electronic states in the semiconductor materials using optical measurements. The important data obtained when some gropes of researchers [1,2] start to investigate the optical spectra modulated by parameters such as: the wavelength, temperature, electrical field… Some particularities of optical spectra, which not founded in the absorption and reflection spectra, it was identified using the modulated spectroscopy.
BUILDING OPTIMIZATION OF THE RIVER ECOLOGICAL BOATS
CAZACU MIRCEA DIMITRIE *, NICOLAIE SERGIU **
One presents the problems which have considered the optimisation building of the environmental friendly bouts, destined to the protected aquatic areas i.e. Romanian Danube Delta and for the river transport in generally. Thus, we have used the renewable energies for the boat propulsion, as well as the solar energy and kinetic river energy, the reduction of energy consumption of the boat propulsion and its government, the functional work optimisation of the hydro-mechanic and electric equipments.
INCORPORATION AND DISPERSION OF THE REINFORCED PARTICLES IN A MATRIX OF AN ALLOY WITH ALUMINIUM BASES
CHIHAI S., ROMAN C., HUŢANU M., MIHĂILESCU N., ALEXANDRU A.
To obtain a metallic matrix composites with a uniform incorporation and dispersion of particles require the control of technological parameters. The fabrication of MMCs by means of casting methods is necessary to prepare a liquid metallic matrix/non-metallic particles suspensions before casting. The Vortex method is one such method to prepare suspensions. In this case the feeding rate of liquid matrix with particles is a important technological parameters which influences the uniformity of incorporation and dispersion of particles within metallic matrix. The present paper shown experimental researchs concerning of the influence of feeding rate on the incorporation degree and dispersion particles in an aluminium matrix composites.
LOW VOC EPOXY COATINGS: PROBLEMS AND OPPORTUNITIES
CIOBANU DOMNICA, TULBURE MONICA, IONIŢĂ IRINA
The modern refinements of these materials are much easier to apply and have found extensive use as tank linings, particularly for wine storage, and in food factories and chemical plants. The aromatic amine has been superseded largely by specially designed aliphatic an cycloaliphatic amine formulations and this trend is set to continue, particularly because of modern labelling requements for DDM based hardeners. Some solvent-free coatings based on non-DDM hardeners, however, are limited by the inability to cure properly if the temperature is very low and humidity is high. The use of water-based epoxies may be unsuitable where chemical resistance is critical or where high humidity prevails during cure, espe¬cially when temperature and air movement are low.
ANTICORROSIVE TITANIUM DIOXIDE PIGMENT IN C0IL CIATINGS
CIOBANU DOMNICA, IONIŢĂ IRINA, TULBURE MONICA
A new type of an environmental friendly anticorrosive pigment was developed simultaneously providing the hiding power of a white pigment. The product is based on a specific titanium dioxide carrier material which is inorganically surface modified with chemically active anticorrosive substances. The new pigment offers corrosion protection and light scattering at the same time, thus opening up new opportunities for formulations of anticorrosive coatings.
A QUALITATIVE ANALYZE OF FLOW SPECTRUM THROUGH WORK MACHINES WITH LATERAL CHANNEL USING NUMERICAL METHODS
CIOCĂNEA ADRIAN, BUDEA SANDA
Papers present a critical analyse of flow spectrum through work machines with lateral channel. We present theoretical results obtained by flow modelling in compressible fluid flow using Fluent application, also in incompressible fluids, using Taylor method for finite differences. The flowing spectres analysed prouve that the efiiciency of the machines increase at the increase of the number of the impeller blades and by decease by ratio of lateral channel width and thouse of the blade, or by the decrease of radial gap from the blades and the cassing. On remark that the kinetic energy increased by the vortex intensity, suitable by a single fluid passing through impeller and cassing, is small because the pressure energy at the discharge of the hydraulic machines, named MCL cannot be changed.
STUDIES ON THE REACTIVITY OF SOME SUGARS AND AMINO ACIDS IN MAILLARD REACTION MODEL SYSTEMS
CIOROI MARIA
The Maillard reaction, an essential way to a non enzymatic proces, takes place among reducing sugars and amino acids, peptides, proteins, byogene amines. The paper objective is to investigate the modifications of both structure and composition in the model systems ?-amino acids-sugars (lysine and xylose, glucose, fructose, glycine and the same sugars) heat treated at 100o C in a static system within 0-10 h. The modifications found in the system were associated with the fragmentation, condensing, elimination, addition, polyaddition and polycondensing processes resulting in new products of unsaturated, conjugated, cyclic and heterocyclic structures.
THE EXERGY - ONE WAY TO USE PROPERLY THE NON-CONVENTIONAL ENERGIES
CIUCESCU EDUARD-PETRE *, ANGHELOPOL GEORGE **
The news energetic politics are very drastically with the pollution emissions. It is necessarily that the actual coil power plants are changing the management of the energy production; like solution for small entities is the use of the non-pollution energies: the potential energy of the geothermal wells, and the kinetic energy due to the power of winds.
THE CHOISE OF THE BEST VARIANT IN A DECISIONAL PROCESS – CASE STUDY
CIUCESCU NICOLETA
The managers may be confronted with situations where they have to choose the best variant in a given situation, that is very difficult especially when the the criteria are not expressed in the same unit of measurement, like, for example: m2, lei, kg, percentage etc. In this case the decider may establish the best action variant taking into consideration all the criteria and using a long list of methods like: method of utilities, method of leader, method of Onicescu etc. In this paper is presented a case study concerning the choice of the best decision using three methods: method of utilities, method of leader, method of Onicescu.
A STRUCTURAL APPROACH TO THE PRODUCT MANAGEMENT
CIUCESCU NICOLETA, MIRONESCU ROXANA
Designing a product means to apply scientific knowledge to the solution of technical problems and then to optimize that solution within the given material, technological and economic contraints. In this paper are presented some important aspects of product management as the problem of establishing the function structure of a product.
STUDY OF A WATER DOZER BY MEANS OF FAST AND VALUE ANALYSIS AND ENGINEERING
CONDURACHE GHEORGHE, BOSINCEANU MIRELA
The aim of this work is to study the possibilities of improving the value of a water dozer using specific creativity techniques: FAST analysis, Value Analysis and Engineering (VAE), as well as statistic investigations amongst the product users. Conceiving novel solutions implies the use of Pareto technique and psychological creativity methods. The solutions assessment is achieved both through VAE techniques and multi-criteria analysis; experimental data were processed using specific software.
ELEMENTS OF COMPARATIVE MANAGEMENT IN COMPANIES FROM ROMANIA
CONDURACHE GHEORGHE, PISLARU MARIUS
This paperwork realizes a comparative study of the different aspects by Romanian company’s managerial activities. The author accomplished one questionnaire which has-been administrated of several managers from different hierarchical levels from Romanian companies. The conclusion which has resulted can represent useful elements for public companies activity improvement.
METHOD FOR ESTABLISHING WET VAPOUR TITLE THROUGH LAMINATION AND STATIC CONDENSATION
DAMIAN VALERIU
This method of establishing the wet vapour title is applied to those consumers of vapour situated at a long distance from the heating station and for which the vapour title is smaller than 0,95. The method will be used when there is no water source on the measurement spot and was applied for the achievement of some energy balances for technological installations in chemical and food industry.
ADVANCED MECHANICAL MODEL FOR DYNAMIC BEHAVIOURAL ANALYSIS OF THE FRONT LOADER TYPE EQUIPMENT
DEBELEAC CARMEN
In this paper the author present a new physico-mathematic model which describe the movement of the frontal changer. The technological equipment is considered as a dynamic system with two masses (the base machine and the equipment loaded with change in the bucket) and five degrees of freedom. The motion of the machine is described by the set of differential equations, based on the second order Lagrange Principle, with proposed hypothesis of energy dissipative systems. To computing the solution for these equations, it was used the classical numerical methods, implemented on the MATLAB™ software numerical application. The model and the method presented in this work constitute a starting original approach for analysis both of a motions of each constitutive elements of the machine, and of a dynamic stresses and strains of the changer equipment metallic structure. The main purpose in this study consist by underlie a complex and complete numerical model, which leads the simulations and the analysis of the effects of the vibrations, produced in the metallic structure of the technological equipment, for the different phases of the working cycle.
MODERN TECHNOLOGIES REGARDING THE USE OF GAS TURBINES
DIACONESCU IOANA, GHELASE DANIELA, DASCHIEVICI LUIZA
Pulp and paper sector is a big power consumer. Pulp and paper mills use electrical and heat power simultaneously in a technological process as process steam. As case stands, solutions have been chosen to assure the electrical and heat power requirement with own heat and power plants. The paper shows a new energy concept in the pulp and paper industry aiming the rise of electrical power output in the mills’ electrical and heat plants. This concept is based on the mixed gas-steam cycle.
BEST WORKING CONDITIONS OF DRYING PAPER PROCESS
DIACONESCU IOANA, DASCHIEVICI LUIZA, GHELASE DANIELA
Within the present paper, a diagram of the wet air (Moliere) is done for a certain working sketch and various working conditions. Thus, the wet air condition (dew point) is determined at the paper machine outlet. Conclusions are drawn concerning the value of the specific thermal energy consumption.
MAGNETIZATION OF AMORPHOUS STROPS OF Fe40Ni40B20 IN PERPENDICULAR NEGATIVE FIELDS.
DRAGOI D. D.
The literature of the domain presents a series of results concerning the magnetic characteristics of hysteresis for various amorphous alloys in strop form, magnetized in unidirectional bields, but no references have been found regarding the magnetization of the strops of Fe40Ni40B20 in perpendicular magnetic fields
THE EVOLUTION OF THE FOREIGN DIRECT INVESTMENT AT THE WORLD LEVEL
DROB CATALIN
This study aims it’s to present the trend and the main characteristic of the foreign direct investments on the world level. The trend has been driven by interaction of technological change, corporate strategies and policy reforms in developing countries. These countries have used different policies and measures to attract the benefits from foreign direct investments. At this moment, at world level, the tendency of the foreign direct investments flow is to grow up.
THEORETIC ASPECTS CONCERNING FOREIGN DIRECT INVESTMENT
DROB CATALIN
This study aims it’s to present the main theories regarding the foreign investments. Early explanations of foreign investments were based on neoclassical theory of international capital movements and trade. These approach were unable to explain very clear the nature and patterns of foreign investments. Lastly foreign investments theories try to find a explanation of these based on new assumption, like the existence of imperfect market and of firm-specific advantages.
THE EVOLUTION OF THE FOREIGN DIRECT INVESTMENT IN ROMANIA
DROB CATALIN, MIRONESCU ROXANA
This study aims it’s to present the trends and the main characteristic of the foreign direct investment on the national level. Inflows of the foreign direct investment in Romania reached the highest level in 2006. In this year, the foreign direct investment volume exceeded EUR 9 billion. The bigger investors are from EU countries: the Netherlands – 17.44 per cent of the total, followed by Austria – 12.96 per cent, France – 10.56 per cent and Germany – 9.79 per cent etc.
THE INFLUENCE OF CONSTRUCTIVE AND FUNCTIONAL PARAMETERS ON THE VOLUMETRIC FLOW RATE TRANSPORTED BY A ROTATING VOLUMETRIC PUMP
DUMINICĂ DESPINA, BĂRAN NICOLAE, BESNEA DANIEL
The paper presents the sketch and the functioning principle of the rotating volumetric pump; a computation relation is established for the theoretical volumetric flow transported by the pump. The manner in which pump geometry and functional parameters influence the volumetric flow rate is also presented. A computation example of the volumetric flow rate and of the pump driving power is presented for a prototype of the pump achieved in the laboratories of “POLITEHNICA” University of Bucharest.
MODELING AND SIMULATION OF AIR POLLUTANT DISPARTION
DURBACĂ ION
This work was carried out to develop a model equation for predicting air pollutant dispersion. Major air pollutant were identified, their source, how they cause air pollution, effects and control measures were analysed. A predictive model for air pollutant dispersion was developed and simulated using data collected from the industry for the year 2004, 2005 and 2006. Both the model and simulated result shows that pollutants such as NO, CO, and CO2 are dispersed in accordance with the law of the dispersion (which state that there is a trend in the reduction of pollutant concentration with increasing distance), The quantities of air pollutants emitted from the industries were compared with that of LEPA/REPA regulated emission limit for each pollutant Hence the model could be used in predicting air pollutant dispersion in air pollution control and the safe distance for human habitation from the industrial area.
LOCALIZED STATES OF THE Sn IN LAYERED SEMICONDUCTOR GaSe
EVTODIEV IGOR
In this article is studied the influence of the concentration of Sn atoms on the electrical conductivity of the crystals ?-GaSe. Sn atoms with concentration less than 0.5% at are uniformly distributed within the volume of the gallium selenide monocristal, and do not change the way of packing of the layers which are characteristic for the polymorphic form ?-GaSe. Doping the gallium selenide monocristal leads to the growth of its electric conductibility by 1-2 orders at room temperature. Variation of the electrical conductivity when the concentration of Sn atoms is changed in the GaSe crystal is determined by the decrease of the number of vacations in the metal substructure (VGa) inside the compound during the process of growing of the monocrystal and decreasing of the density of the localized states.
THE WOMAN AND THE MANAGEMENT
FERARU ANDREEA
Women, trustful in their ability, give themselves place, in a business world still dominated by men. We read the newspapers, we listen the radio or we are informed by TV about women that decide to leave the company they have worked for a long period of time, in order to develop their own affair..
ADVANCED TECHNIQUES FOR RELATIV MOTION STUDY OF MATERIAL POINT
FILIP VIVIANA, NEGREA ALEXIS
The aim of this paper is to present the mathematical techniques for solving the material point dynamics applications, which contain two order differential equations, unlined, which cannot be solved by analytic methods. In such cases it is easily to work in advanced mathematical software, such as Mathematica, which permit to determine a solution by numerical methods. The time for calculus is by order of seconds.
AN ALGORITHM FOR THE DIRECT AND REVERSE FIRST ORDER KINEMATICAL ANALYSIS OF THE INDUSTRIAL ROBOTS AND MANIPULATORS
FILIP VIVIANA, DUTA LUMINITA, PATIC PAUL CIPRIAN
In this paper we present a method based on matrix calculus that allows to find the angular and linear velocities of a robot/manipulator, if we know the kinematical intermediary elements (the links and the determination of the velocities of links if we know the kinematical elements of the characteristic point of the robot/manipulator.
ATTITUDE EVALUATION UNDER STRESS FOR WELDED JOINTS THROUGH CORROSION TESTING
FLEŞER TRAIAN
Welded joints attitude of construction steel pipes is evaluated after tracing the bending static stress cycle in a technological process steam environment. A program is run, which envelopes further deformation in aggressive environment exposure, mechanical trials, and metallographic examinations. The results showed different effects to degradation, correlated to welded joints nature respective initial welded qualification. The results are used for preliminary long term exploitation capacity.
INVESTMENTS AND INVESTORS
FLORESCU DANIELA
The paper represents a study about the most attractive countries for the investors, the resident ship of the given funds and the evolution of the profit tax region by region.
FIGHTING FOR INSUFFICIENT RESOURCES
FLORESCU DANIELA, FLORESCU IULIAN
Not very long ago, men’s and nations life was determined by the availability of the necessary resources for survival and for maintaining the existing life style. The nomads used to change their places in search of food - the most precious of all resources. In some countries, the transport development, permitted them to enlarge the domination sphere through commerce or conquest and to bring home the necessary raw materials, instead of moving on and on for their search. The frontiers opened more and more in order to permit them a large access to these resources.
EXPERIMENTAL STUDY OVER 3D SCANNING
GANEA BOGDAN, MOISĂ OVIDIU, SCHNAKOVSZKY CAROL
This paper refers to the scanning of different products using 3D laser scanning. For the experimental study it was used the LPX-600 scanner created by Roland (Japan). The scanned piece was a highly complex statuette which raised many problems concerning the 3D scanning accuracy.
CONTINUOUS IMPROVEMENT OF QUALITY
GHELASE DANIELA, DOGARIU CONSTANTIN1, DASCHIEVICI LUIZA
The paper presents some aspects regarding continuous improvement of quality, such as: Kaizen strategy, Deming Cycle PDCA, the „5 S” Method and Quality Circles, methods which can be applied in order to drive a manufacturing process towards excellence.
SEVEN MANAGEMENT AND PLANNING TOOLS
GHELASE DANIELA, DASCHIEVICI LUIZA, DIACONESCU IOANA
Thanks to globalization and rapid advances in technology, today’s manufacturing environment is increasingly competitive. Manufactures need to stay focused on finding new ways to design, produce, sell and deliver products. So, the paper presents seven management and planning tools which promote innovation, communicate information and successfully plan major projects.
THE RIGHT CHOICE OF CAMS FOR AUTOMATIC TOOL CHANGER (ATC)
GHENADI ADRIAN, SILAV CONSTANTIN
In this paper, the research target is interacting cams mechanism ATC. Maine work is done in designing with computer. All the design process is researched especially in dynamic property analysis and calculating. Some results and analysis method such as estimating the tool changing time accorded to the moment of inertia. Set up tool holder turnover dynamic model, etc., can be used in ATC’s design to improve the ATC’s working quality. Using CAD for ATC’s design will increase the quality and speed in design especially in various types ATC and MC.
THE QUANTITATIVE EVOLUTION OF STRUCTURAL CONSTITUENTS IN BALL-BEARING STEELS, DEPENDING ON THE PARAMETERS OF THE THERMIC TREATMENT
GHEORGHIAN M. *, ROSCA V. *, CHIHAI S. **
The spinning precision and the functional role of ball-bearings enforces upon them a good dimensional stability and good/satisfying mechanical properties during the functioning. These properties depend on the nature of the structural constituents, on their size and distribution, on their level of structural homogeneity. The substantial modifica-tions of the exploitation proprieties emerge from important modifications in the compo-sition, structure and substructure of the ball-bearing steels. These modifications have been brought into light by research in the domain of the optic microscopy and by X ra-diation difractography. The choice for the final thermal treatment is made taking into consideration the chemical composition of the steels, the characteristics imprinted to the steel by the former processing and by the final obtaining of the structural constituents – which – through quantity, size and distribution – are supposed to ensure the technical and qualitative conditions imposed to the ball bearing.
HOW TO DETERMINE THE BRIILENESS OF THE HARD SUPERFICIAL METALIC LAYERS
GHEORGHIAN M.*, ALEXANDRU A. **
This paper presents how to determine the brittleness of the hard superficial me-tallic layers. The apparatus we designed and produced allows of a pyramidal diamond cone to be pressed with a force F on the flat surface of a metallic test sample, ground and pol-ished.
SPREADING MECHANISMS OF CHARGE CARRIERS IN GALLIUM ANTIMONID DOPED WITH IRON
GHEORGHITZA EUGEN, GUTULEAC LEONID, MELINTE VICTORIA, ZLOTEA OLGA, POSTOLACHI IGOR
Obtaining, homogenizing, and purifying technologic conditions of the gallium antimonid doped with iron and simultaneously doped with iron and tellurium. According to the research of galvanometric features of non-doped gallium antimonid and gallium antimonid doped with iron in 3 atomic % concentration for the temperature pitch of (4,2÷300K) the mechanisms of charge carriers spreading were analyzed. It is demonstrated that for experimental data explanation obtained for the U=U(T) function it is necessary to involve an additional mechanism of charge carriers spreading specific for the inclusions formed in gallium antimonid – clusters. Using the physic conceptions of this mechanism the basic characteristics of spreading the charge carriers determined by clusters were calculated.
LC OSCILLATOR DESIGN
GRIGORESCU LUIZA
The circuit that will be presented offers a flexible alternative to implement a function and to simulate an inductance. The inductance simulated by this method is used in order to obtain a very high frequency (MHz) oscillator. A circuit with two CCII current-conveyors with opposite polarities and three passive components fulfill the inductance simulation.
APPROACHES TO THE INVENTION OF NEW CURRENT-MODE OSCILLATORS
GRIGORESCU LUIZA
The current-conveyor is a versatile analog device which is intended to be used with other circuit components to implement many analog signal processing functions. It is an analog circuit building-block in much the same way as a voltage op-amp, but it presents an alternative method of implementing analog systems which traditionally have been based on voltage op-amps. This alternative approach leads to new methods of implementing analog transfer functions, and many cases the conveyor-based implementation in terms of accuracy, bandwidth and convenience.
RENEWABLE ENERGY SUPPLY IN RURAL AREAS
GRIGORIU MIRCEA, DINU DOINA, CIOBANU GHEORGHE
The energy suppliers have to face some untypical situations in the rural areas, such as isolated seasonal locations of energy necessities, according to the geographical position and the consumption graphic. The common and expensive solutions are: connection to the power network and utilization of a Diesel generator. The smart solution is the utilization of some local renewable energy sources, generally available in this type of geographical locations. The paper offer a modular optimized solution designed to use satisfy the typical renewable energy sources, wind and solar radiation. In fig.1 it is presented the power supply schema, providing optionally a back-up generator. The application is based on the natural conditions from some typical Romanian locations. The added value of the paper consists in the optimization of the common solutions in an integrated system. Also, the paper provides real finalized solutions for real situations.
RESEARCH CONCERNING THE PURIFICATION OF THE WASTEWATER RESULTED FROM THE GALVANIC PROCESSES. I. THE RETENTION OF THE Zn IONS RESULTED
HARJA MARIA 1, RUSU LACRAMIOARA 2, BANDRABUR FLORIN 1, HARJA CONSTANTIN 3
The industrial wastewater is an important source of pollution. Within this category, the water from the galvanic industry is especially important. The purpose of this paper was to monitor the exhaust water from a vapour galvanizing installation, in order to establish the medium values of the zinc ion concentration, to analyze the water after the first stage of chemical treatment and to establish the appropriateness of continuing the retention process of the zinc ions from the chemically treated water. Preliminary tests have been made for the retention of the zinc ions, concerning their retention by using ion changing devices and power plant ashes.
SOME ASPECTS REGARDING THE INFLUENCE OF ELASTICITY OF WORKING MEDIUM OVER MECHANISM KINETICS
HAUK NICULAI, CIUREA AUREL
In classical mechanic theory it is consider that the element of a box are stiff. That theory provides calculation results which, in some situation can’t be accepted. In reality, the elements of the mechanism are made from materials which have different elasticity. Under the action of forces, elements are deformed so, the mechanism kinetics is affected. This paper shows case of mechanism which has more then 1 mobility, drived by hydraulic cylinders on which the working medium is more elastic then steel. That medium became element into the passive hydraulic cylinder, which seriously affect the mechanism position.
NATURAL ZEOLITES: INDUSTRIAL AND ENVIRONMENTAL APPLICATIONS
VASSILIS J. INGLEZAKIS1, ANTONIS ZORPAS
Natural zeolites are the least-known treasures for industrial applications, environmental pollution control, separation science and technology. Natural zeolites are volcanic minerals with unique characteristics. Their chemical structure classifies them as hydrated aluminosilicates, comprised of hydrogen, oxygen, aluminum, and silicon, arranged in an interconnecting lattice structure. The arrangement of these elements in a zeolite crystal gives rise to a honeycomb framework with consistent diameter connecting channels that vary in size from 2.5 to 5.0 angstroms, depending on the type of zeolite mineral. This unique structure makes zeolites different from other aluminosilicates (kaolin, bentonite, etc.) due to the following special properties: the ability to selectively adsorb molecules of gases and vapors, the ability to reversibly absorb/desorb water without any chemical or physical change in the zeolite matrix and the ability to exchange inherent cations for other cations on a basis of ion selectivity. The present paper reviews the critical properties of natural zeolites and important uses in industry and environmental-related applications.
THE PHYSICAL SIGNIFICANCE OF SIMPLIFIED MODELS IN ENGINEERING
INGLEZAKIS J. VASSILIS
It is a common question of an engineer: the used model is a description of the underlying mechanisms or just a useful tool for design predictions with no further physical meaning? For the engineer, a good model is the one that closely represents the reality and can be treated without too many mathematical or other computational and experimental complexities. For that reason, instead of using a complicated theoretical model, which includes a number of difficult to be measured parameters, engineers prefer to use several simplified empirical models, which are based, in most of the cases, on a number of “reasonable” assumptions and approximations. However, advocating the use of simple theories and models makes it necessary to point out the pitfalls, which are encountered in their application. A theory is completely useless unless it reflects the most important properties of the system to which it is applied. Any theory must first be checked as to whether it meets this criterion [1]: its “physical significance” is always a critical issue.
NEW SELF-CROSSLINKINQ, OPTIONAL DUAL-CURE ACRYLIC DISPERSIONS FOR FURNITURE OR PARQUET COATINGS
IONIŢĂ IRINA, CIOBANU DOMNICA, TULBURE MONICA
Acrylic dispersions with very small particles and specially designed particle morphologies can be used to formu¬late waterborne wood coatings which do net appear milky and meet the mechanical and chemical resistances of conventional solventborne systems. When modified with an additive, these systems exhibit a dual-cure mechanism and feature characteristics that reach or outperform those of common D.I.Y. parquet coatings. Over the past decades acrylic dispersion wood coatings used in the do-it-yourself sector have proven excellent dry film performance combined with ease of use. Also, the inherent environmental and safety benefits of this water-based technology favoured its increased use. A specially designed formulation additive leads to an ambient dual self-crosslinking mechanism, providing wear resistance properties that make the system suitable for the formulation of parquet coatings.
CREATING WATERBORNE SOLUTIONS FOR INTERIOR WOOD-COATINGS
IONIŢĂ IRINA, TULBURE MONICA, CIOBANU DOMNICA
In this paper two new products-ranges: one-pack self-cross I inking acrylic dispersions for the industrial wood coatings market are highlighted.When applying conventional solventborne coating systems on an industrial coating-line, organic solvents are being released into the earth`s atmosphere. In order to comply with European legislation, these emissions must be reduced by means of correspondingly expensive and complicated technical equipment such as solvent recovery, post-combustion, etc.
COMPUTER SIMULATION OF LIQUID-SOLID SEPARATION - HYDROCYCLONE WHIT TWO CONICAL SECTIONS
IPATE GEORGE, CĂSĂNDROIU TUDOR
Computational modeling and simulation of irrigation systems have received the greatest attention today because of large amount of energy consumption. The use of water containing suspended sediments causes serious problems to irrigation systems. Prefilters, such as the hydrocyclone, are important for their significant capability of retaining particles suspended in the water. In this paper commercial CFD (Computational Fluid Dynamics) package called Ansys is applied to build a computational model of hydrocyclone whit two cone sections and calculate the results of separation process. The hydrocyclone has modeling whit the proper geometrical relationship between the cyclone diameter, inlet area, vortex finder, apex orifice, and sufficient length providing retention time to properly separation particles. The main parameter is the hydrocyclone diameter Dc=250 mm. Two models, i.e. Plitt’s (1976) and Lynch and Rao (1968) have been used to describe the performance of hydrocyclones, which by linking to separation device model allows for closed-circuit simulations. By comparing the outputs of ANSYS with previously existing simulators results published in the subject literature, particularly FLUENT, its performance was firmly validated both in terms of accuracy and precision of obtained results.
THE OPTIMISATION OF THE FEEDING ZONE OF A SINGLE SCREW EXTRUDER, FROM THE FLOWRATE POINT OF VIEW
JINESCU V. COSMIN
Feeding zone flowrate of screw extruder depends on the friction coefficients between the granular material and screw and the granular material and barrel. When the barrel is grooved on the internal surface, two friction coefficients are to be considered: one corresponds to the movement on the direction of the screw channel width (x), while the other corresponds to the movement on the direction of screw channel axis (z). Based on the performed experiments regarding the dependence of the friction coefficients on the allignement of grooves on the internal surface of the barrel and the calculations for the flowrate in the feeding zone, the conditions needed for the friction coefficients resulted. This gives us an indication on the roughness that the screw surface as well as the barrel internal surface in the feeding zone need to have to insure maximum flowrate in given geometrical conditions.
INVESTIGATING OF MICRO-MECHANICAL COMPONENTS FROM ACTUATING TRANSMISSION MECHANISMS (?CTUATORS)
KARTUNOV STEFAN
Paper deals with survey and analysis of different types micro-actuators, used in micro-drives. A classification and a coding system of micro-drives as components of micro-technics have been invited with examples. The technological process has been analysed depending on the row material and the specific application. A technological process has been developed for micro-drive component producing (|miniature harmonic gearing) – a gear-wheel made of phase-connected material – alloy NiFe with module m = 35 ?m and process charts have been represented.
THE USE OF EFFICIENT LINING METHODS COMBINED WITH NUMERICAL MODELS FOR OPTIMUM PROJECT MANAGEMENT OF MANUFACTURES
1 KOLIOPOULOS T.C., 2 KOLIOPOULOU G., 3 AXINTE CRINA
This paper presents useful solutions for efficient management in technical infrastructure works’ manufacture. Effective lining methods combined with dynamic numerical models are analysed in order not only to support dynamic reclamation works minimizing any associated environmental impacts but also to utilize effective maintenance and rehabilitation of particular manufactures. In the end, useful conclusions are made for the necessity of using proper lining methods based on the spatial characteristics of particular engineering designs.
OPTIMIZED MANAGEMENT IN CURVED MANUFACTURES’ DESIGN USING EFFICIENT LINING METHODS
KOLIOPOULOS T.C. 1, KOLIOPOULOU G. 2, AXINTE CRINA 3
This paper presents efficient lining methods which should be used in the diagnosis, management, maintenance of machineries and structures. Effective lining methods and quality assurance solutions are proposed in order to provide quality assurance and maintenance of machineries and of sustainable structures, minimising any associated risks. In the end, useful case studies are presented and conclusions are made for the necessity of using proper efficient lining methods.
AN EFFICIENT ITERATIVE ANGLE TRISECTION LINING METHOD FOR THE MANAGEMENT OF CURVED MANUFACTURES IN TECHNICAL DESIGNS
KOLIOPOULOS T.C. 1, KOLIOPOULOU G. 2, AXINTE CRINA 3
This paper presents an efficient lining method which confrontates the most common met problems in the manufacture management of several machineries and structures. Effective solutions are presented in order to develop quick and accurate lining methods for the diagnosis and quality assurance of the manufactures in their life cycle. In the end, useful case studies are presented and conclusions are made for the lining, construction, diagnosis and maintenance of machineries and infrastructure works.