bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study of Compression Engine Cycle Behavior in Terms of Variable Gazodynamic and Geometrical Configuration. Regime of the Maximum Economy
Authors: Omocea Ion
Published: November 2013

In this analysis, the variable configuration requires a variable distribution. This takes account of the areas offered by the valves and resistance gazodynamic coefficients. All at once the law of efficiency variation describes the variation of the power law. Cycle behavior was analyzed for the following values of the pressure drop coefficient on admission: 5%, 10%, 20% and 40%. For the calculations is necessary to determine the dimensionless heat developed by combustion. I used the following values: for the pressure drop coefficient on admission I use ψa=10 % and for the share of gazodynamic on the suction route conductance in total conductance I use .With this configuration imposed and with (dimensionless heat developed by combustion) resulted: (mean indicated pressure cycle) ; ηv = 0,876 (cylinder filling coefficient) ; α = 1,515 (excess air coefficient) and ηi = 0,499 (indicated cycle efficiency) ; (dimensionless indicated power ); (dimensionless heat taken combustion gas) ; (dimensionless heat taken environment). After numerical analysis result a maximum efficiency with relatively low dissipation.
Quality Oriented Self-Optimizing Control in Smart Machining Systems
Authors: Park Hong Seok , Tran Ngoc Hien
Published: November 2013

In recent years, due to the hard competitiveness through globalization most manufacturing companies have focused on manufacturing higher value added products with low production costs. So, it is inevitable to apply the advanced technology to carry out it in effective and efficient way. Monitoring and control of machining processes are becoming increasingly important for keeping a consistent quality of machined parts. The paper presents in-process sensing and control techniques with applying information science for the next generation of quality control that eliminates the need for expensive post-process inspection. In this research, a machining process of machine tool is considered in terms of a quality oriented control. The self-optimizing control is proposed for enabling intelligent process monitoring and control which can detect the cutting conditions and status of machining operations. To prove the proposed self-optimizing control system, self-monitoring and self-adjusting, the machining process related to the tool condition such as tool wear was considered in this paper. The most crucial and determining factor to successful maximization of the manufacturing processes in any typical metal cutting process is tool wear. The evolutionary algorithm was developed to diagnose the tool wear. If the amount of tool wear is out of the allowed limit, the new cutting parameters should be generated and adjusted autonomously according to affecting the quality of the machined part through the tool wear.
Issues Concerning Vibrations Reduction of the Industrial Drilling Machine in the Manufacturing Processes
Authors: Pasăre Minodora Maria , Ianăşi Aurora Cătălina
Published: November 2013

The paper set the differential equations of free vibration for straight helical rods, in a general matrix form, with which determine the pulsation equation as an algebraic equation of n degree. The coefficients of this equation contain geometrical and elastic characteristics including natural degree of torsion bar and also the boundary conditions at the ends. These coefficients provide important information about the machine-tools from the mechanical industry under the action of vibrations, during execution the processing operations on the industrial products.
Grapho-Analytical Determination of the Profile Disc Tool for Manufacturing of Complex Helicoidal Surfaces
Authors: Pleşu Gheorghe
Published: November 2013

Helicoidal surfaces correspond to a cathegory of widely spread surfacesin the technical field. From the point of view of the manufacturing of helicoidal surfaces through the moving of a profile around the helix, the two elements defining such a surface can be distinguished: the profile and the helix. The numerical determination of the profile of the disc type tool drawn on an analytical method with a large number of points [1- (the number reaches even 1500 in some cases) implies a great effort so that the technician can verify the correctness of results, even in the present case when there is the possibility of the numerical determination through the resolution of the inverse problem of the frontal profile of the complex helicoidal surface. In order to facilitate this work and to give the possibility of introducing some new profiles in the projection system, some methods of grapho-analytical determination have been conceived to process the profiles of the complex helicoidal surfaces, as well as the profiles of the helicoidal surfaces for a given tool profile. This paper presents the graphic-analytical determination of the disc tool profile designed to dress the complex helicoidal surfaces. The methods referred to by using the possibilities provided by the programming environment AutoCAD and its development languages allow to determin numerically the profile of the disc-cutter with a high precision, above the precision level required in practice.
Thermal Analysis to Evaluate Ageing Process in Heated Tool and Electrofusion Welding of Polymer Pipes
Authors: Savu Sorin Vasile , Savu I. Danut , Ciupitu Ion
Published: November 2013

Heated tool and electrofusion welding are the most used joining processes of higher than 2 mm thick polymer pipes. The two welding processes have different heating-cooling cycles and they produce different influences on the properties of the polymers. Exploitation of polymer pipes for water and gas distribution revealed ageing behaviour of the material in the welding area. The modification of the behaviour depends on the base material, on the applied welding process and on the used parameters. Thermal analysis can be used as tool to reveal and to evaluate the modification of the physical and mechanical properties. Such knowledge is important when prediction of the in use life is necessary to be predicted. Experimental programme was applied to HDPE 100 and HDPE 80, both welded using heated tool and electrofusion processes and different sets of parameters (factorial experiment principles were used to establish the welding parameters). Plasticity characteristics of the welds material, as elongation and relaxation modulus, were determined by using thermal analysis. Burst stress test, applied to the pipe, was considered. It has been observed important rate of the heating process of the surface in contact with the heater. The DSC analysis revealed a decreasing of the elongation with about 12% and decreasing of the relaxation modulus with amount up to 14%, for the material located at the interface between pipe and the heater. At 0.5 mm from the interface it was revealed an intensity of the modification up to half of the values recorded for the interface. That was explained on the poor thermal conductivity specific to the both materials. By using DSC thermal analysis it has been revealed that the polyethylene has high rate crystallization during welding cycle, after the heating to the viscous state. Such crystallization, together with potential non-uniformity of the heating provides modifications in the geometrical characteristics of the weld. For high energy input, the material experience large quantity of fluid material with important plastic distortion. That means high possibility to reject material during pressing step of the welding cycle. 10% increasing of the temperature, for the same heating pressure, involves 5-8% increasing of the dimensions of the fluid ring in the interface. About 10% difference between the relaxation modulus of the heated and non-heated HDPE and that means local ageing transformation of the HDPE. The material becomes more fragile than before the welding process.
Studies Regarding Production of the Moulding Form from Calcined Gypsum
Authors: Simionescu Gheorghe , Gheorghian Mirela
Published: November 2013

In the pressing form made from calcined gypsum fixed in metal, wax can be cast with pressure. The device used to tide the pressing form should not bend. If the handling work is done carefully and correct one pressing form made from gypsum can be used for multiple wax models. To be used in construction the pressing forms, calcined gypsum must meet certain requirements regarding its constitution and functionality. To provide these requirements research work must be done to investigate characteristics such as: minimum compressive strength (wet and dry state), hardening time of calcined gypsum, gypsum dilatation after curing. To produce the pressing forms from calcined gypsum the following methods and operations have been used: operations concerning production of gypsum with the best physicochemical and mechanical properties in order to be used for construction of pressing forms (determining the quality of gypsum based on water and plaster ratio; establishing the influence of epoxy and curing solution on the mechanical resistance of the obtained gypsum; determining the influence of lime, boric acid, zinc chloride, sodium chloride on the hardening period of calcined gypsum); production of the models from wood and metal; fixing the model on the gypsum cushion; finding on the model the separation line and restrict the area used for gypsum moulding; applying grease on the model, on the plate under the model, on the walls and on all parts that come in contact with liquid gypsum to be poured; preparation of the gypsum solution.
Smart Engineering and Energy Saving Management in Edible Oil Processing Technology and Speciality Fats Industrial Application
Authors: Vintila Iuliana
Published: November 2013

The present paper research performs an overwieved study regarding the engineering activities involved in the industrial design of the edible oil plant units. The objectives of the proposed smart engineering plan were to increase the oil extractability in the condition of process performance analysis of total integrated manufacturing facility, flexible tailor-made production, financial performance analysis and ecological industrial processing. Modern manufacturing operation via mechanical method of oilseeds pre-pressing associated with performant oilseeds preparation (drying, craking, dehulling, flaking) were considered to be analysed in the smart engineering for tailor-made end-product of higher commercial quality.
Protective Coatings on Carbon Steel
Authors: Barhalescu Mihaela Luminita
Published: November 2013

The experimental research aim was to analyze the corrosion resistance of superficial layers obtained by electrical sparking on the steel carbon samples. The electrodes used in these processes being made from corrosive resistance materials (coper and nickel). Processing by electric sparking occurs through electrode material erosion (anode) with a transfer by erosion products on the superficial workpiece. Processing of the treated surface begins with approximation of electrode by sample and at critical interval, it triggers electrical discharge through impulses. It is often continuous and ends at the electrodes contact. At the contact surface of the electrodes appear areas strongly heated causing electrical erosion of the electrodes (sample and electrode). The predominant transfer of anode material (electrode) to the cathode (the sample) ensures the formation superficial layer. After it the discharge was complete, at very small time interval, start removal of the Anode by cathode, action which ends with the interruption of electric circuit due to the transfer of material and the thermal changes from discharge area, in the superficial processing of metallic materials with electric sparks, the superficial layer of cathode it changes its structure and chemical composition. The samples being immersed 285 days in static sea water at the environments temperature. Corrosion resistance in seawater of superficial layers obtained with copper and nickel electrodes was determined by gravimetrical method. The samples covered with thin layers immersed in the corrosive agent (sea water) were analyzed through optical microscopy using QX3 Intel Play microscope and through atomic force microscopy. Experimental results were compared for both the surface of the initial sample material (OL 37) and the surface of the samples covered with Cu and Ni layers. One of the conclusions is: the superficial layer obtained by electrical sparking using cooper and nickel electrodes proves a improved corrosion resistance to see water compared to the base steel, specially for long term tries, when the corrosion speed is stabilizing remaining almost constant. The second main conclusion is: the investigations through atomic force microscopy made on the samples tested for long term corrosion, accentuate the compact and homogenous surfaces areas, which had not permitted the corrosive agent to interact with the base material.also, the wave-mode images present the discontinuities of the superficial laid layers, which represent a possible access way in for the corrosive agent to the samples material.
Comparison of Corrosion Behavior of Thin Layers from Copper, Aluminum and Chromium
Authors: Barhalescu Mihaela Luminita
Published: November 2013

The aim of this research is to determine the corrosion resistance on superficial layers laid-down through electrical sparking on the steel carbon OLC 45 samples, the used electrode being made from corrosion resistant material (Aluminum, Copper and Chromium). The superficial treatment through impulse electrical discharges is a procedure through which the proprieties of the metallic materials can be improved. The proprieties of the superficial layers obtained through this procedure are the same as the electrodes material being used or very close to this one, the properties resulting from micro alloying and the diffusion of the electrode material in the sample of steel. The experiments were done, for the superficial treatment through impulse electrical discharges, using Al, Cu and Cr electrodes. The corrosion speed was determinate through electrochemical corrosion. The corrosion potential and marking the polarization curves (linear and cyclic) was determined with an advanced electrochemical system type VOLTALAB 32. The acquisition and processing of experimental data was made with the help of the specialized software VOLTMASTER 2. The corrosion potential was determined by tracing the curves of linear polarization, recorded in sea water, using the Evans coordinates: E = f (log I). The corrosion process analysis was made also based on the cyclic polarization curves. The fine determining of the topography surfaces exposed to the action of the corrosive environment was made using the atomic force microscope (AFM). The support but also the sparking probes, has present the same type of corrosion; a general corrosion, which in the initial moments is represented by the appearance of corrosion dots. The superficial layers laid through Cr, Al and Cu electrodes sparking proves a improved corrosion resistance to see water compared to the base steel. Aluminium has the highest corrosion tendency while copper has the best protection.
Reseachers Concerning Stabilized Aluminium Foams Based on Silicon Carbide
Authors: Bălţătescu Oana , Florea Raluca Maria , Buzăianu Aurelian , Roman Costel , Carcea Ioan
Published: November 2013

To obtain SAF we have focused research on Al-Mg alloys with different concentrations of magnesium and silicon carbide (SiC). To obtain these materials has been chosen different gas blowing method (N2, SO2 and C4H10). It was observed that the best results in terms of pore volume gave blowing with C4H10. The samples obtained were analyzed by optical and electron microscopy.
A Comparative Analysis of New Ti-Nb-Zr-Ta Orthopedic Alloys
Authors: Bărbînţă Andreea Carmen , Chelariu Romeo , Benchea Marcelin , Crimu Carmen Iulia , Strugaru Sorin Iacob , Munteanu Corneliu
Published: November 2013

Ti-Nb-Zr-Ta alloys represent a new generation of biomaterials with possible applications in the orthopedic field, being developed in order to eliminate the negative aspects of the current orthopedic biomaterials, which consist mainly in a low biocompatibility with human tissues and high values of modulus of elasticity compared to the human bone. This paper presents a comparative study of new titanium alloys, corresponding to the Ti-Nb-Zr-Ta system: Ti-21Nb-6Zr-15Ta and Ti-25Nb-10Zr-8Ta, which were analyzed by scanning electron microscopy, X-ray diffraction and microindentation. The both alloys are classified as near-β alloys. The addition of alloying elements such as Ta, Nb and Zr represents a good solution for lowering modulus of elasticity, which is an important factor for reducing bone resorption and therefore for preventing implant failure.
New Composite Materials that Reduce the Effect of Reinforcement Corrosion
Authors: Constantinescu Vasile , Bogus Gheorghe Veniamin , Taran Rares George , Carcea Ioan
Published: November 2013

Concrete is a complex material of construction that enables the high compressive strength of natural stone to be sed in any configuration. In tension, however, concrete can be no stronger than the bond between the cured cement and the surfaces of the aggregate. This is generally much lower than the compressive strength of the concrete. Concrete is therefore frequently reinforced, usually with steel. When a system of steel bars or a steel mesh is incorporated in the concrete structure in such a way that the steel can support most of the tensile stresses and leave the immediately surrounding concrete comparatively free of tensile stress, then the complex is known as reinforced concrete. Corrosion of reinforcing steel in concrete leads to the premature failure of many structures exposed to harsh environments. Rust products form on the bar, expanding its volume and creating stress in the surrounding concrete. This leads to cracking and spalling, both of which can severely reduce the service life and strength of a member. Corrosion of reinforcing steel in concrete structures is one of the most expensive problems facing civil engineers in the world. The structural integrity of many bridges, overpasses, parking garages, and other concrete structures has been impaired by corrosion, and repairs are urgently required to ensure public safety. Corrosion-induced deterioration of reinforced concrete can be modelled in terms of three component steps: (1) time for corrosion initiation; (2) time, subsequent to corrosion initiation, for appearance of a crack on the external concrete surface (crack propagation); and (3) time for surface cracks to progress into further damage and develop into spalls, to the point where the functional service life, is reached. The two most common causes of reinforcement corrosion are: (i) localized breakdown of the passive film on the steel by chloride ions and (ii) general breakdown of passivity by neutralization of the concrete, predominantly by reaction with atmospheric carbon dioxide. Sound concrete is an ideal environment for steel but the increased use of deicing salts and the increased concentration of carbon dioxide in modern environments principally due to industrial pollution, has resulted in corrosion of the rebar becoming the primary cause of failure of this material. The scale of this problem has reached alarming proportions in various parts of the world. Corrosion in reinforced concrete structures is causing deterioration of our infrastructure. Structures in or near marine environments and transportation structures on which deicing salts are used are especially vulnerable. A widely promoted method for repairing damaged structures or for protecting structures in corrosive environments is the application of fiber-reinforced composite wraps over the surface of the structures elements.
Application of New Synthesized Materials Based on Anionic Clays for Industrial Effluent Decoloration
Authors: Dartu Laura , Zaharia Carmen , Carja Gabriela
Published: November 2013

This work reports hydrotalcite and zinc-substituted hydrotalcite (MeAlLDHs) anionic clays as novel catalytic formulations for some environmental applications regarding specific industrial coloured effluents. In this context, layered double hydroxides, covered or with tailored compositions, were synthesized, characterized using advanced analytical analysis techniques (XRD, FTIR, SEM) and tested in specific environmental applications. More specifically, LDHs samples were tested as catalysts for different treatments of coloured effluents, especially some advanced oxidation processes (i.e.heterogeneous advanced oxidation processes with H2O2of Orange 16 dye-containing effluent). The influence of some operating factors such as catalyst type, concentration of hydrogen peroxide, presence of ferrous ions or UV light, contact time was studied, and the adequate operating values were established. Results show that Orange 16 removal is more than 70%, in specific operating conditions, for two of new tested materials (ZnAlLDH 3:1, and MgAlLDH 3:1). Moreover, the action of UV radiation was found efficient in decomposition of Orange 16 dye in the presence of all four tested catalytic materials, improving with more than 40-50% the color removal.
Abrasive Wear of Fibre-Metal Composites Based on Fibreglass Woven Fabric Layer
Authors: Zolkiewski Sławomir
Published: November 2013

The tested specimens are fibre-metal laminates. The samples are made as a connection between a metal sheet plate and a fibreglass laminate. Epoxy resins or polyester resins were applied in matrix of the composite. In this paper the exemplary results of testing on abrasion of composites with the fibreglass laminate plate were presented. Thanks to the results it is possible to estimate and compare the surface quality of the samples together with the joint of the fibreglass laminate. In assumed testing group of laminates, it is also possible to compare the impact of different basis weight of fabrics on the level of abrasive wear. The most proper material properties such as a type of connection or basis weight of applied laminate fabric were defined. In order to determine the degree of abrasive wear of tested samples and evaluate the testing results the methodology of research was assumed as: abrasive test and the visual valuation, measurement of mass decrement, measurement of geometrical structure of the composite's profile on the side of laminate. Taking into consideration the results of testing the weighed and calculated mass losses of the particular samples were compared. The measurements were taken in accordance with the EN ISO 12947-3:1998 norm.
Improving of the Functional Parameters from Water Stations
Authors: Alexandrescu Aurora , Miron Simona Adina
Published: November 2013

The evaluation of connections between the functional parameters of hydraulic systems and the quality indicators of water, depending on time is obtained with the help of an original automatic calculation program, elaborated by authors. The original automatic calculation program defines the exploitations regimes for the overall outputs installation to be maximum, the total typical energy consumed to be minimum on the work cycle ensemble and the water quality to be according to international settlements. Follow the variation in hydraulic slope water transport channel, the variation between the weir and hydraulic ram level variation. The water depth studies the variation in drainage canal in biological stage.
Analysis of Surface Roughness for High Speed Milling of a Magnesium Alloy Part
Authors: Chirita Bogdan , Tampu Nicolae Catalin
Published: November 2013

Surface roughness represents an important characteristic in the appreciation of a part quality. A good surface quality can enhance corrosion resistance and fatigue behavior throughout product life cycle. Magnesium alloys have gained in the recent years a larger use due to an excellent ratio between mechanical strength and weight. Cooling conditions are particularly important when machining magnesium. The chips are flammable and highly reactive with water based fluids. Higher temperature favors also the formation kamiya@cc.tuat.ac.jpof built-up edge and worsens surface quality. The present paper analyses the influence of cooling conditions and cutting parameters on surface roughness of the parts made of magnesium alloy. Using design of experiments technique, a series of experiments were organized and based on that a connection between surface quality and cutting conditions was established.
Analysis of Simulated Welding Thermal Cycles S700MC Using Thermal Imaging Camera
Authors: Górka Jacek
Published: November 2013

In this paper an influence of simulated thermal cycle on properties and HAZ structure of 10 mm thick S700MC steel plates. The introduction of thermomechanically processed steels with high yield and relatively low carbon equivalent, will significantly reduce the time of welding works by reducing the preheating temperature, or even complete removal of this processing step, furthermore reduction of cross-sectional areas of structural elements, making welded structures with the same capacity will be more slender and lighter. The simulation of thermal cycles was carried out on a specially built test stand equipped with resistive heating source infrared camera VarioCam Head HR with 50 mm lens and a computer with software IRBIS 3 plus. Simulation was prepared for simple and complex thermal cycle. Simulation studies of thermal cycles consisted of resistive heating of samples prepared for the impact test. Single thermal cycles were simulated at temperatures ranging from 400 to 1300 oC, 100 oC and the cycle complex. For each temperature three repeats were carried out. Specimens were tested on impact, strength test and also hardness and metallographical tests. The study showed that there is a possibility to use a purpose built system to simulate simple and complex thermal cycles of S700 MC steel in specific ranges of the cooling time t8/5. Analysis of the results of the study showed that the welding thermal cycle strongly influences the structural changes and phase in the HAZ zone of S700 MC steel. Areas of HAZ heated to high temperatures above 1000 [°C], show a sudden drop of toughness to unacceptable levels of impact strength (27 [J/cm2]). This sharp decrease in toughness is associated with uncontrolled separation processes of MX phases and dissolution of carbides, niobium and vanadium carbonitrides in austenite during heating. The study also showed that the chemical composition of steel and especially titanium and aluminium content is sufficient to bind in the HAZ free nitrogen and reduce the aging process. The control of the amount of heat introduced into the joint area during welding will reduce the adverse separation processes in the weld and HAZ which will ensure adequate toughness of the connection. Precise knowledge of the phenomena occurring in the HAZ during the thermal cycle can impact the ability to control properties and structure of the welded joint.
About Variability of Using of Methods of the Shape Identification Based on Geometrical Correlation
Authors: Gostev Ivan
Published: November 2013

Methods of identification of the form of objects based on the signature analysis and invariant to affine transformations are considered. It is shown that these methods can be applied to surface quality assurance. Questions of sensitivity of these methods are considered. Dependences of these methods on noise are brought.
Aspects Concerning the Dynamics of the Mechanisms with Clearances
Authors: Grigore Jan Cristian
Published: November 2013

The clearances in the cinematic links appear due to the long functioning. In the paper we shall make a few considerations of geometric and mechanic type about the clearances in the linkages, linkages planes with rotation joint links. We shall elaborate methods to study the influence of the clearances. Consider a rotational kinematic coupling clearance, the clearance being defined by the distance, difference between the radius of the bearing and the radius of the journal. This relationship between elements is unilateral. Journal's behaviour inside the bearing can be highlighted the value normal reaction force. The journal can have the following phases, phase contact (when there is contact between the bearing and journal, the normal reaction force is zero) flight phase (no contact between end journal bearing at this stage is normal reaction force 0). It is considered the most dangerous phase, recovery phase of flight phase where the contact is restored. In this phase occurs shocks, shocks in turn produce vibration in the mechanism leading to the destruction of the system. The clearance size is directly proportional to magnitude impact and vibration level especially high. To be reduced or even eliminated these shocks, the paper presents a solution. Crank Mechanism with clearance, mechanism considered in this paper applies a force so that maintain contact between the bearing and journal, is considered the center of gravity of the connecting rod the forces and the moment. Based on the relations obtained from equation echililibru and vector equation of the contour goes to the numerical calculation for the engine element is inserted angle value (which defines the initial position of the mechanism), one deduces the angles, which define the position of the mechanism. Any would be their source of appearance, they usually produce unwished effects during the mechanisms functioning.
The Model of Discrete Production Scheduling System in UML Notation - Classes Diagrams
Authors: Kalinowski Krzysztof , Grabowik Cezary , Paprocka Iwona , Kempa Wojciech M.
Published: November 2013

The modeling phase of the computer system development is one of the most important elements affecting the final success of the created software. Structures developed at this stage are the basis for the design and implementation of computer program code. The paper presents the general model of static structures (main classes and their relationships) of production scheduling system supporting discrete and multiassortment production. In the description of the object-oriented model a graphical systems and specifications modeling language notation UML was used.
The Graph Representation of Multivariant and Complex Processes for Production Scheduling
Authors: Kalinowski Krzysztof , Grabowik Cezary , Kempa Wojciech M. , Paprocka Iwona
Published: November 2013

The paper presents a solution useful for production scheduling in the context of the constraints arising from the complexity of the structures of realized processes and possibilities of use variants of their implementation. The proposed method uses both activity on arc and activity on node types of graph for describing multivariant processes. Representation of complex (composed) structures the AND-OR graphs are used that combines both conjunction and disjunction relations between nodes.
Theoretical and Data-Based Mathematical Model of a Special Vehicle Breaking System
Authors: Marinescu Marin , Vilau Radu , Truta Marian , Vinturis Valentin , Fieraru Octavian
Published: November 2013

Military vehicles have to travel, at least from time to time, on the national road network. Whenever that happens, the A military vehicle doesnt have to meet all the requirements of a civilian vehicle. Moreover, its lifecycle is much longer than a civilian vehicles one. This is the reason a military vehicle doesnt have to meet all the requirements that a civilian one has to. Nevertheless, traffic security asks for periodical checks of the braking, steering and other systems. In this respect, we have been contracted to develop a method to assess the braking systems parameter of a certain class of military vehicles. When an assessment is involved, we usually develop a basic mathematical model to be the basic feature for further investigation. Since for the old vehicles there are no database, we have created two models, one by numerical simulation and the other one by processing the experimental data. Should be mentioned that prior to use one of them for further analysis, we had to check for the models accuracy. Data have been achieved using a very up-to-date measuring system. Moreover, the data was subject to filtering procedures, taking into account the noises of the system and different other measuring errors. We have tested several vehicles that were in good technical condition. All in all, we have tried to create a reliable database that should stand back from a trusting point of view.
The working characteristic features of a process can be synthetically expressed as a mathematical model. For the technical systems, this model can be obtained either based on the mathematical expressions that describe the working way of the systems components or on data-base grounds that have been previously achieved throughout experimental research. As far as the validation of the mathematical model is concerned, the modelling error should be kept under tight control. Therefore, the researcher has to permanently determine the difference between either the simulated and measured output parameters. Eventually, the validated mathematical model can be used to analyse the dynamic performances of the system or a proper way to improve them, as far as the actual evolution of the system is accurately enough described.
Key words:
vehicles,
braking system, theoretical models, data based models, modelling error
Pressure Waves Simulation in Diesel Engine Injection System
Authors: Sabau Adrian
Published: November 2013

The aim of this study is to present a mathematical model for the wave pressure in the Diesel injection system. The method of characteristics and the finite difference method have been used to solve the governing equations. Recent studies show that finite difference method is superior to the method of characteristics concerning computation time and nonlinearity. The injection process of a high-speed Diesel engine was studied in detail, using an original computer program developed in MATLAB. The governing equations are solved by the use of the finite difference method with central pattern at space coordinate in combination with the separation of flux vector. The fuel injection system is divided into pump, pipe and nozzle component to model the entire system. When forming equations of continuity and motion the following assumptions are considered: all the equations have 1D spatial resolution, temperature change due to pressure and time during the cycle is not considered, the vapors pressure of the fuel is small compared to the level of the pressure injection system, it is assumed that cavitation will not occur and elastic deformation in the injection system is not considered. The experiment is carried out to measure the fuel consumption, in-cylinder pressure, the fuel injection pipe pressure near the injection valve and needle lift for several regimes of the working domain of a Diesel engine. The experimental set-up includes a 4 stroke cycle 4 cylinder Diesel engine T684 made by Tractorul Brasov Romania. Simulations show satisfactory results, in principal for regime of low speed, for regime of high speed it is important to take into account cavitation and the elasticity of the component; but improvements are possible. Since the models are developed for certain conditions it was not expected to be valid for all working conditions. Targets for further research related to the present work is to improve the model attaching submodels for cavitation and elasticity of the component
Some Peculiarities of the Redundant Design Solutions
Authors: Gonçalves-Coelho António , Neştian Gabriela , Cavique Miguel , Mourão António
Published: November 2013

In common speech, the term redundant is used to label superfluous repetitions that as a rule should be avoided. Nevertheless, redundancy is a linguistic tool that can play a remarkable role in the communication of complex thoughts in both the vernacular and the erudite talking or writing, which includes the field of engineering design. In the Axiomatic Design (AD) point of view, redundancy may increase the complexity of the design solutions (which is measured through their information content), but does not necessarily entail the breach of the ADs independence axiom. Hence, redundant solutions should not be excluded in a regular basis, since the ones that comply with the independence axiom are considered good design. According to this line of reasoning, the pertinence of redundant solutions should be assessed in the onset of the designing processes, bearing in mind the virtues of the likely higher simplicity of the non-redundant solutions. This paper deals with some basic concepts related to redundant design and it should be seen as a contribution to bring more insight on a subject that is not thoroughly reviewed in the known literature. Different forms of redundancy are considered, specifically the reliability motivated active and passive types, and the functionality-related alternative and augmentative kinds. The means to perceive intrinsic redundancy through the examination of the design equations are also provided, as well as some illustrative examples. The implicit conclusions are that redundant designs are much more usual that one can think at a first glance, and that the study of their peculiarities might deserve further attention.
Design and Realization of a Sound Module for a Miniature Model Steam-Locomotive
Authors: Ursu Mircea Petru , Buidoş Traian , Albert Gyorgy
Published: November 2013

This paper shows the main steps to design and realize an original sound module for a miniature model steam locomotive, which produces the adequate sounds and the characteristic steam puffing in synchronization with the wheels of the locomotive. This continues the previous work of the authors concerning the model railroading and the implications of nonconventional technologies in this field of activity.
Drying Simulation of Shrinkable Clay Tiles Using Variable Diffusivity Model
Authors: Vasić Miloš , Radojević Zagorka
Published: November 2013

This paper represents the upgrade of our previous study in which we have presented a model for simulation of the drying kinetic and estimation of the effective moisture diffusivity of clay tiles using a constant diffusivity model. The main objective of this study is to determine the time - dependent effective moisture diffusivity of shrinkable clay tiles. Experimental investigations were carried out, on clay tiles, in a laboratory recirculation dryer in which drying parameters (humidity, temperature, and velocity) could be programmed, controlled and monitored during drying. Results presented in this study have shown that the proposed drying model describes and correlates accurately drying kinetics and gives a reliably estimation of the time - dependent effective moisture diffusivity.
Complex 3D Measuring by Multiple Laser Scanning of Automotive Parts
Authors: Voicu Adrian Catalin , Gheorghe Gheorghe I.
Published: November 2013

For over 20 years the term"three-dimensional scan"(3D) showed the world the possibilities of virtual design, simulation, or reverse engineering. 3D scanning is also known as 3D digitizing, the name coming from the fact that this is a process that uses a contact or non-contact digitizing probe to capture the objects form and recreate them in a virtual workspace through a very dense network of points (xyz) as a 3D graph representation. Until recently, digitization was limited by the speed of the scan head and the correct choice of the probing system, type of scanned piece and budget for the purchase or develops the scanning system. With the evolution of technology appeared a number of new techniques that tend to improve the properties of classical methods. Even if intended for copying or geometrical control, or rather virtual geometric modelling or product realization, there are two groups of technologies: with contact (classical methods with probes) or without contact (laser, optical or combination). Most automotive manufacturers currently use 3D scan metrology based on optical or laser systems to validate products quality. The pieces are initially measured by 3D scanning then they are compared with the designed model (CAD file) using a specialized software. By this comparison producer can interfere very quickly in the manufacturing process to remove the cause of defects, this technique being called Reverse Engineering (RE). There are many variables that affect accuracy of laser scanning and therefore the quality of information: reflectance of surface, colour object, recesses, openings narrow and sharp edges can be difficult to scan. This accuracy may vary from micron to millimetre and the acquisitions size from a few points to several thousand points per second. The overall accuracy of a 3D acquisition system depends above all on the sensors precision and on the acquisition device (acquisition with contact) or acquisition structure (acquisition without contact). In a perfect world or in an integrated production environment, 3D measuring systems should be able to measure all the necessary parameters in a single step without errors, and to render the results in the same way to the manufacturing networks equipped with computers, in formats useful for machines control and processes management.
Controlling a Social Robot - Performing Nonverbal Communication through Facial Expressions
Authors: Adăscălitei Florentina , Doroftei Ioan , Lefeber Dirk , Vanderborght Bram
Published: November 2013

This paper focuses on our primary goal to achieve the emotional behaviour of the new version of the social robot Probo. The ability to enhance nonverbal communication with children is possible through facial expressions, eye-tracking and face-to-face contact. The new social robot has 21 degrees of freedom (DOF), grouped in five subsystems, named generically: eyes, ears, trunk, mouth and neck. The robotic head is actuated using only servo motors and all the components are manufactured using cheap, flexible and easy technologies. In order to get the social robot head able to express emotions, a Graphical User Interface (GUI) was developed. In this way facial expressions are created through sliders or push buttons. Additionally, we investigated the possibility of controlling the robot with an Arduino board. In this case, using pre-programmed or learned algorithms, the robot is getting a semiautonomous level, based on the usage of various sensors, being able to express six basic emotions: happiness, sadness, fear, anger, surprise and disgust. So, based on the feedback provided by the sensors, the robot can react accordingly, enhancing human-robot interaction (HRI).
Functional Evaluation and Performance Improvement of a Gantry IR’s NC Axes
Authors: Avram Georgia Cezara , Nicolescu Florin Adrian , Anania Florea Dorel , Strajescu Eugen
Published: November 2013

The paper presents main results obtained from experimental works performed for functional performances evaluation of a gantry robot, used for ultrasonic flaw detection (NDT Automation standard-duty ULTRA PAC Ultrasonic immersion model). The functional status of the robot has been evaluated by mean of a RENISHAW LASER ML 10 interferometer measuring system, from the point of view of positioning accuracy and repeatability in position as well as geometric errors of each gantry IR's NC axes. The research stages are referring to: individual NC axis functional evaluation (experimental determination of IRs X, Y, and Z axis positioning accuracy and repeatability in position), overall IRs NC axes functional evaluation (identifying of the partially geometric errors induced by inaccurate mounting of IRs joints / links or inappropriate technical solutions adopted for assembling different structural elements / joints of the studied gantry robot), as well as IRs X NC axis functional improvement (X NC axis positioning accuracy optimization) by mean of software errors compensation. The experimental setup included the analyzed gantry robot and the laser calibration system associated with different mountings of the laser measurement optics system (interferometers linear reflectors) for each measurement procedure. The final results and conclusions relieve means to functionally improve both, individual NC axes' as well as overall IRs performances.
The Command of a Virtual Industrial Robot Using a Dedicated Haptic Interface
Authors: Butnariu Silviu , Gîrbacia Florin
Published: November 2013

In this paper is presented a study regarding the possibilities of commandinga virtual robot using a haptic interface. In order to demonstrate the functionality of this concept, a dedicated device with 1 DOF was developed. This device consists of twin motor-gearbox able to acquire and transmit the angular data of the shaft and return a haptic feedback corresponding to the robot movement. The proposed haptic device makes it possible to command one joint of an industrial robot and can be used as an essential component for the development of an exoskeleton for human arm and is able to generate a haptic interaction for all the joints. The exoskeleton solution will allow a structural similarity between the haptic device and an articulated robot arm. The test results with haptic feedback scenarios show that the proposed system can help inexperienced users to handle robot operation and programming tasks in an intuitive way.
Mobile Robot Trajectory Analysis Using Computational Methods
Authors: Coman Daniela , Ionescu Adela
Published: November 2013

This paper presents some considerations regarding the trajectory analysis for a class of mobile robots, namely two-wheeled differential drive mobile robots, one of the most utilized mechanical structures now in mobile robotics practice. The paper is continuing the computational analysis of the Cauchy problem associated to a mobile robot kinematics. The phaseportrait graphical tool of the mathematical soft MAPLE11, points out the influence of the initial conditions the initial velocities of the driving (left and right) wheels of the robot on the robot trajectory. Considering a pair of few simulation cases for the initial conditions brings a good reliability of the analysis. The issue of repetitive phenomena is very important to notice in this context, as in the analysis it is repeated a specific allure of the trajectory. It brings important features, both from mathematical and robotic analysis standpoint. The further changes are due to the initial conditions variations. Repetitive phenomena can be collected in order to realize a global panel of random distributed events in the kinematics of two wheeled differential drive mobile robot and to use the statistical observations in the further analysis.
Kinematic Modelling and VR Simulation of a 3DOF Medical Parallel Robot with One Decoupled Motion
Authors: Cretescu Nadia , Neagoe Mircea , Saulescu Radu
Published: November 2013

The robot studied in the paper has a 3DOF parallel structure of type 1PRRR+2PRPaR, with two coupled motions and one decoupled motion, composed by a mobile platform connected to the fixed base by three kinematic chains (one open kinematic chain of Prismatic Revolute Revolute Revolute type and two kinematic chains of Prismatic Revolute Parallelogram Revolute type). An analytical kinematic modelling of the parallel robot of type 1PRRR+2PRPaR is firstly presented in this paper, followed by a numerical simulation of the closed-form kinematic model and by a Virtual Reality (VR) application with control aspects. An innovative user interface for high-level control of the parallel 1PRRR+2PRPaR type robot is developed in MATLAB - Simulink and SimMechanics environment.
Preliminary Ideas on Designing an Unmanned Aerial Vehicle Based on Coanda Effect
Authors: Crivoi Ovidiu Vasile , Doroftei Ioan , Adăscălitei Florentina
Published: November 2013

The final goal of this research is to develop a safe and inexpensive flying vehicle. In this paper, only some preliminary ideas on the design of an unmanned aerial vehicle, based on Coandă effect, will be presented. These ideas are concerning the optimization of the aerodyne body profile.