Home ] Up ] For Authors ] Peer Review ] Board ] Indexing ] Site Contents ]

Home
Issues Archive
For Authors
Peer Review
Board
Indexing
Site Contents

Recent 27

Vol. 10 (2009), No. 3 (27)

The 27th issue of RECENT journal was edited and multiplied with support of:

  • Romanian Association for Nonconventional Technologies

  • Transilvania University of Brasov, Romania

  • Brasov County Council (by Scientific Activities, Education, Culture, Cults Committee)


CONTENTS


  • Magdalena BARBU, Gheorghe BONCOI

TOOL MANAGEMENT IN THE PRODUCTION SYSTEM

» Abstract. The paper herein puts forth a few introductive notions connected to managing the tool flux within an enterprise. The notion of „tool flux” is defined, enhancing the differences from the material semi-manufactured product flux. Any factory, whatsoever the product it processes and whatsoever the type of material processing, is vulnerable to internal perturbations, among whom the variation of the tool flux is of major importance. Preventing vulnerability is achieved through management in real time, which, for eliminating the penury and the surplus, has to ensure the minimal safety stock, regulated through managerial decision. The main issue of tool management consists in the fact that “at request, any tool, of any type and dimension, must be available within the right time, at the right place” so as to cast off the tool penury in the system.

» Keywords: management, school flux, monitoring

PDF

Back to Top


  • Diana BĂRGLĂZAN, Anca DRĂGHICI, Mihaela VARTOLOMEI

ECO-EFFICIENCY – THE NEW DIMENSION OF ECONOMIC EFFICIENCY

» Abstract. Over the past decades, human activity has changed the world’s environment more extensively than ever before. Slowly, the people became sensitive to the needs of our environment. Nowadays, it is clear: in order to be sustainable, economic development must respect the environment. All over the world (but especially in Europe), people, companies and governments attach an overwhelming importance to protecting the environment. At macroeconomic level, more and more policies focus on environment protection. At microeconomics level, in order to have success in the long-run, companies cannot neglect the environmental dimension of business development. More and more companies use environment friendly technologies and present them as a strong competitive advantage, in their commercials and advertisings. The World Business Council for Sustainable Development (WBCSD) developed the concept of eco-efficiency. This concept covers a wide range of measures by which companies have reduced their environmental impacts and also their costs. The use of eco-efficiency indicators allows us to avoid the traditional problem referring to the fact that environmental performance indicators might fluctuate as a result of changes in production volume and thus hide real changes in environmental performance. The paper analyses the way Europeans see sustainable development and their initiatives oriented towards achieving the symbiosis between economic development and environment protection. From these initiatives, we focus especially on the micro-economic measures. We investigate the ecological way of doing business, and we measure the eco-efficiency of several well-known companies, trying to outline the solutions that work best, solutions that could be used by the Romanian companies in order to increase their eco-efficiency.

» Keywords: eco-efficiency, sustainable development, environmental performances

PDF

Back to Top


  • Ionela BUCŞE, Ion CIUPITU, Adela IONESCU

THE ANALYSIS OF THE TECHNOLOGIC PARAMETERS INFLUENCE IN OBTAINING THE ALLOYED SINTERED STEELS BY TWO-STEPS SINTERING

» Abstract. In the paper there are presented the results of the experimental research for elaborating Mn, Mo, Cr, B and Graphite alloyed steels. There were elaborated mixings with 3% Mn and Fe, 1.5% Mo, 1% Cr and 0.5% B, which have experienced a 20, 40 and 60 hours mechanical alloy and produced nanocomposite mixings with powder grains of about 300nm. In this sense there were compactized samples at 600, 700, 800 MPa. The samples were heated in argon, at 1250 ºC, then in the same cycle the temperature were reduced at 1100 ºC, and kept 60 minutes. There were analyzed both the samples obtained by two-steps sintering and the samples obtained by classic sintering. The experimental results pointed out that the nanostructured steels obtained by two-steps sintering have an increasing of the density, structural homogeneity and mechanical properties (hardness, friction coefficient), comparing to the classical sintering. There is also presented the optimization of the technological process of elaborating the alloyed steels. In this purpose it is used the factorial experiment and is established that the polynomial model of degree 2 is optimal for estimating the output surface corresponding to the required experimental element. The results of the graphical data processing using the soft STATISTICA 8.0 proved interesting information concerning the variation of the mechanical characteristics of the alloyed steels.

» Keywords: mechanical alloy, nanocomposite, alloyed steels, two-steps sintering, polynomial optimization

PDF

Back to Top


  • Gavrilă CALEFARIU, Adriana FOTA, Cristina GĂVRUŞ, Flavius SÂRBU, Magdalena BARBU, Nicolae BOIAN

MANAGEMENT OF MANUFACTURING SYSTEMS’ ADAPTING AND DYNAMIC STATE TIMES

» Abstract. This paper contains a checking of the times consumed on the manufacturing flow. Operational, auxiliary, adapting and dynamic regime times, for different manufacturing tasks and organizational types are pointed out and calculated. Determination of the item’s and batch’s manufacturing time, under the conditions of serial and parallel disposal of the workstations has been had in view. It starts from pointing out the motions within and outside of the workstation. Possible organizing cases of the activities needed for the system’s adaptation to the manufacture of a new item and the consequences of partly overlapping the transient regime time on the adapting time, have been checked. By calculating adapting and transient regime times for each of the cases identified hereby as being possible, premises of drawing up managerial decision variants have been created. The determination of these times is useful in fixing performances related to the system’s output and to the calculation of manufacturing costs. They are essential in designing manufacturing systems. The optimal management of the item change adapting times and of the transitory regime times represents an important requirement of the actual economic reality. Ensuring the market competitiveness, presumes manufacturing cost reductions, firmly respected supplying terms and small manufacturing batches.

» Keywords: flexible manufacturing systems, dynamic state, adapting times

PDF

Back to Top


  • Dumitru CATRINA, Ştefan VELICU, Lucian MIHAI, Alexandru VELICU

KNIFE THREADING ON MULTI-AXIS AUTOMATIC LATHE AND CNC LATHE

» Abstract. Threading is a largely used operation in equipment, tools, machine tools construction and facilities for making screws and nuts for clenching or movement with different profiles. Most cylindrical or tapered threads are done on lathes, with the knife but also by milling. In this paper, it is presented in the first part, disk shaped devices, the threading knife with a knife and the pins associated for threading on multi-axis automatic lathe, designed and implemented for production of various components in large series. In the second part is the summary of the possibilities of threading on CNC lathes typically used in small and medium series production, but not only.

» Keywords: threading, multi-axis automatic lathe, CNC lathe

PDF

Back to Top


  • Dumitru CATRINA, Marius PARASCHIV

UNFOLDED PROFILE OF CYLINDRICAL CAMS OF MULTISPINDLE AUTOMATIC LATHE

» Abstract. Multispindle automatic lathe is a machine tool of high complexity. Such lathe is used to manufacture large or mass series of products, generally made out of metal bar. Having specialized devices, the lathe can manufacture products out of individual cast or forged work pieces. This paper presents some achievements in multispindle automatic lathe command shaft’s cylindrical cams design.

» Keywords: cylindrical cams, multispindle automatic lathe

PDF

Back to Top


  • Cătălin-Iulian CHIVU, Catrina CHIVU

NEW MATLAB FUNCTIONS APPLIED TO MECHATRONIC SYSTEMS

» Abstract. In the study of mechatronic systems, in particularly of robotics, the constant concern is the location of objects in three-dimensional space. These objects are the links of the manipulator, the parts and tools with which it deals, and other objects in the manipulator's environment. At a crude but important level, these objects are described by just two attributes: position and orientation. Naturally, one topic of immediate interest is the manner in which we represent these quantities and manipulate them mathematically. Matlab program offers some toolboxes that may help but, almost all of them implies to create a geometric model and to generate some input matrixes. All these toolboxes can be used only after many hours of learning, even if the user has very good Matlab knowledge. This was the based idea of the present paper. In this paper the authors present some functions created in Matlab and oriented on mechatronic systems, particularly on robots.

» Keywords: robotics, Matlab, SCARA robot, mathematical model, simulation

PDF

Back to Top


  • Cătălin-Iulian CHIVU

SYSTEMS MOVEMENT DATA ACQUISITION

» Abstract. In the present paper, author introduces a system that is used to plot the experimental characteristics of rotational or linear mechanisms movement. The system presented here has an incremental transducer, a microcontroller connected to the computer through RS232 interface and software of data processing and graphic representation of the acquired data.

» Keywords: pneumatic muscle, microcontroller, characteristics

PDF

Back to Top


  • Daniela COMAN, Adela IONESCU, Mihaela FLORESCU

MANUFACTURING SYSTEM MODELING USING PETRI NETS

» Abstract. This paper presents the modeling and simulation of a manufacturing system using Petri nets. A manufacturing system consists of robots, computer-controlled machines, numerical controlled machines, computers and automated guided vehicle. Timed Petri nets are used to model, simulate and evaluate the manufacturing system. The Petri net model is implemented in Petri Net Toolbox under MATLAB environment. It is achieve the graphic construction of the net. Then, transporting it into a specific mathematical formalism it is made, so that the fulfilled structure to be fully retrieved and used to bring out the internal dynamics of the model. There are determined the global performance indicators in order to evaluate the performance of the manufacturing system.

» Keywords: manufacturing system, discrete event, Petri nets

PDF

Back to Top


  • Daniel CRISTEA, Cristian IONESCU, Alexandru MUNTEANU, Daniel MUNTEANU

THE CORROSION CHARACTERIZATION OF Ti-Si-C THIN FILMS OBTAINED BY MAGNETRON SPUTTERING DEPOSITION

» Abstract. Nano-composite layers, formed by a mixture of crystalline or amorphous nano-phases, which include Ti-Si-C type layers, obtained with the help of the PVD process, have attracted lately a wide interest both in research, and in the industrial applications, because of their possibility to form a protective coating with physical and chemical unique properties. With this process there can be obtained hard coatings with a high degree of toughness, with an excellent wear resistance, characterized by a low friction coefficient and a good corrosion resistance. The present paper contains both general data about the Ti-Si-C system, and the experimental results obtained from the deposition of Ti-Si-C layers on a rapid steel substrate, at low temperatures. This way, there can be seen some correlations between the deposition method used, the chemical composition and the corrosion resistance, determined using the salt fog (salt spray) chamber method.

» Keywords: thin layers, deposition, Ti-Si-C, corrosion

PDF

Back to Top


  • Ioan CRISTIAN

MATHEMATICAL MODELLING AND NUMERICAL SIMULATION OF COULOMB FRICTION

» Abstract. This article proposes the dry friction simulation diagram which highlights the mechanical hysteresis. Two dry friction distinct relations, one non-linear relation and one portion linearized relation are examined and numerically simulated. The numerical simulation highlights how the mechanic hysteresis introduced by dry friction manifests, depending on the value of the travel velocity and on the start /stop process.

» Keywords: Coulomb friction, mechanic hysteresis, numerical simulation

PDF

Back to Top


  • Ioan CRISTIAN

INFLUENCE OF SPOOL SUPPLIED FLOW NON-LINEARITY ON THE BEHAVIOUR OF THE HYDRAULIC MOTOR

» Abstract. This article studies how non-linearity of the flow supplied by the electrohydraulic servovalve spool influences the dynamic behaviour of the controlled linear hydraulic motor. It approaches the case of hydraulic spool materializing a zero lapped spool, with control edges in circular shape. The analysis is performed comparatively with the linearized flow case, indicating the differences and applications domain.

» Keywords: zero lapped bridge, non-linear flow

PDF

Back to Top


  • Alexis DAJ, Andreea CHIRCA

DIGITAL MARKETING INSTRUMENTS: USING ONLINE COMMUNITIES FOR PRODUCT INNOVATION

» Abstract. The pervasive diffusion of digital, IP-based Information and Communication Technologies has opened-up a vast array of opportunities for marketing researchers to explore and analyse the intricate fabric of socio-economic human behaviour far beyond the limits of business contexts. While a growing number of marketing scholars support the idea that consumers “produce”, giving actual value to the goods and services that they consume, the newly acquired knowledge has led to a profound change in the way marketing professionals conceive marketing, as a whole, and the marketing mix, in particular. Nowadays, marketers emphasise the importance of co-generating value by involving customers in the design and improvement process of goods and rendered services. Consumers participate in the creation of goods and services by not only reacting, sometimes critically, to companies’ modes of providing, but – more fundamentally – by constructing their consumption objects, both physically and culturally. Consumers develop the key components of a consumption culture (knowledge, meanings, and affect) and contribute to its progress, regardless of the market.

» Keywords: online communities, ICT marketing tools, Web 2.0 marketing strategy, service-dominant marketing logic

PDF

Back to Top


  • Alexis DAJ, Andreea CHIRCA

MARKETING STRATEGIES: INNOVATIVE FINANCIAL SERVICES – DETERMINING OR OVERCOMING THE CRISIS

» Abstract. The financial crisis is believed to have a triple root: a policy of easy money kept going too long, an international securitization of heterogeneous debts whose structuring was almost incomprehensible, and a lax regulating attitude, largely tolerated by supervisory authorities. Financial innovation has managed to transform illiquid and risky instruments into apparently safe and liquid assets. In order to overcome this crisis, banks will have to implement new marketing strategies and reposition themselves towards a more careful risk evaluation. The main measures adopted are related to improving sales productivity, developing innovative services, using remote channels, pricing and risk management, origination and servicing optimization, IT optimization.

» Keywords: innovative financial services, marketing strategies, the banking system, financial crisis

PDF

Back to Top


  • Tudor DEACONESCU, Andrea DEACONESCU, Georgiana LIMBĂŞAN,Izabella ICHIM, Cristina GĂVRUŞ

PNEUMATIC MUSCLE ACTUATED EQUIPMENT FOR THE PASSIVE EXERCISING OF INFERIOR LIMB BEARING JOINTS

» Abstract. Applying passive exercising as part of the recovery programme of patients with post-traumatic disabilities of the bearing joints of the inferior limbs requires the development of new high performance equipment. The paper discusses a study of the kinematics, construction and actuation of a novel, pneumatic muscle actuated rehabilitation system for continuous passive motion. The utilized energy source is compressed air ensuring complete absorption of the end of stroke shocks, thus minimizing user discomfort.

» Keywords: equipment, passive exercising, bearing joints, pneumatic muscle

PDF

Back to Top


  • Gheorghe DELIU, Mariana DELIU

ROLLING DISK DYNAMICS

» Abstract. The present paper aims to establish the differential equations of the motion for a homogeneous disk, which is rolling upon a rough horizontal plane. The results will prove useful in a future research, when the motion of a monowheel vehicle will be studied.

» Keywords: rolling, disk, motion, monowheel

PDF

Back to Top


  • Gheorghe DELIU, Mariana DELIU

MONOWHEEL DYNAMICS

» Abstract. The present paper deals with the dynamics problem of a vehicle having a single wheel – the monowheel. Because of the particular kind of contact link between the vehicle and road, the dynamics of such a vehicle is not very simple. The authors present the way to find the motion equations, which are commented, in order to offer a better understanding of such a vehicle motion.

» Keywords: monowheel, motion, equations

PDF

Back to Top


  • Konstantin DIMITROV

FAULT DETECTION IN INDUSTRIAL AIR - PROCESSING SENSORS CONTROLLED SYSTEM

» Abstract. The paper describes the development of enhanced model-based and knowledge-based techniques, which are used for fault detection in air-processing, sensors controlled system, under real operation conditions. The developed modelling equations, knowledge based techniques and fuzzy logic decisions are applied for providing reliability enhancement and fault tolerance in industrial air-processing system, which represents an integral part of a general waste-processing system, designed for a zing galvanizing facility.

» Keywords: fault detection, reliability enhancement, fault tolerance, process modelling, knowledge-based techniques, air-processing systems

PDF

Back to Top


  • Dumitru DUMITRU, Eugen STRĂJESCU

THEORETICAL CONSIDERATIONS CONCERNING THE DETERMINATION OF VALUE FOR THE CRITICAL SPEED OF THE BALL SCREWS FROM NUMERICAL AXES STRUCTURE

» Abstract. A servo performance limit of the numerical axes from the numerically controlled machine tool structure is the first natural frequency of their mechanical structure, because this limits the maximum amplification on the system control loops. For this reason, it is very important the appraisal for the critical speed of the ball screws from the numerical axes structure made by a more exactly calculation procedure. Generally, the ball screw manufacturers offer in the instruction manuals, charts for the ball screw critical speed appraisal dependent on dimensions and type of their pillows. This method for the appraisal of the critical speed value is not a very accurate one, so that, while the feed velocities achieved by the numerical axes of the numerically controlled machine tools are increased, a more exactly calculation method is necessary for the optimization of the amplification parameters for the control loops. This paper aims to elaborate a calculation method for the critical speed of the ball screws from the numerical axes structure, as critical bending speed, which corresponds to one of the natural resonant frequencies, the first natural resonant frequency of the assembly consisted of the ball screw and its pillows being considered as significant frequency in this case.

» Keywords: ballscrew drives, critical speed

PDF

Back to Top


  • Aurel FRATU, Laurent VERMEIREN, Jean-Francois BRETHÉ

STUDY OF THE ASSEMBLY MOTION FOR A VIRTUAL ASSEMBLY SYSTEM

» Abstract. This paper describes the virtual assembly automation systems, as decision support systems, for the better knowledge of assembly operation. The study of this procedure is described as well as the necessity for assembly systems design. The work draws on research into product and manufacturing knowledge models. In this paper, the authors have proposed a virtual prototype model for assembly system architecture of robotic assembly automation. This paper presents a methodology for solid modeling in a virtual environment that is precisely performed in an intuitive manner through constraint-based manipulations Constraint-based manipulations are realized by allowable motions for precise 3D interactions in the virtual environment. A mathematical matrix is presented for representing allowable motions. A procedure-based degree-of-freedom combination method for 3D constraint solving is presented for deriving the allowable motions from constraints. A prototype system has been implemented to testify the feasibility of the presented methodology.

» Keywords: virtual robotic assembly systems, solid model representation, constraint-based manipulations

PDF

Back to Top


  • Vanessa GARCÍA

TEACHING IN ENGLISH “MANUFACTURING SYSTEMS” TO STUDENTS WHOSE MOTHER TONGUE IS NOT ENGLISH

» Abstract. All along this paper, I will try to put into words the impressions collected about my lectures during the last academic course. For the first time I have lectured in English, which is not quite usual in my town as English is neither my mother tongue nor of the students attending to my lectures. Therefore, we have made use of a widely-spread language along the world to teach/learn a subject in English which has nothing to do with English philology, but with a field of engineering, more specifically with the Manufacturing Systems. To prepare myself before marking the beginning of this journey towards quality applied to technical teaching, I have attended to different courses to improve in my speaking in English in public, to learn how to write papers in English, and how to organise a presentation for different kind of listeners. To sum up, I have tried to do my best to make the students feel motivated to learn something in English without going to a University abroad, which is not perhaps a possibility for everybody even nowadays. With that aim, apart from the common theoretical lectures where the teacher speaks and the students listen quietly, I have used different media to complement the teaching. In one hand, I have used videos in English so that the students can make themselves familiar with the listening abilities and can visualise the manufacturing process that we are explaining in that moment in the theoretical lectures. In the other hand, I have organised visits to a pair of Manufacturing Companies in the surroundings of our town, so that the students can feel in person how it is the real Manufacturing world. Also, the students have developed their abilities in speaking in English technical vocabulary by preparing in pairs presentations in the lectures. To finish, apart from the theoretical learning the students have been provided with a practical learning, where they have experienced to programme in CNC language with the assistance of a simulator on a computer of what is a turning process and a milling process. Afterwards, they have seen the simulated work pieces being machined in a real lathe and in a real milling machine in our laboratory of machine-tools in the University College.

» Keywords: quality, teaching, technology, engineering, manufacturing systems

PDF

Back to Top


  • Cristina GĂVRUŞ, Adriana FOTA, Gavrilă CALEFARIU

ORIGINAL SOFTWARE PACKAGE FOR CALCULATING THE SELLING PRICE OF INDUSTRIAL PRODUCTS

» Abstract. The present paper highlights the great importance of the selling price of the industrial products, as an indicator for the economical efficiency of the engineering activities that led to the creation of an industrial product. The present paper is focused on expressing the selling price of industrial products by including the designing cost of the product in the category of direct costs. In this way it is developed an original software package that allows the rapid calculation of the selling price. The software package was created by using AutoCAD designing environment and VisualLISP and DCL programming languages, being very easy to use. The software product is based on a mathematical model that unlike other mathematical model met in the specialized literature, which include the designing cost within indirect costs, considers this type of cost a direct cost. This approach is based at least on two reasons. One is the fact that expressing the designing cost as a direct cost allows a company to identify possibilities for cost reduction. Other reason refers to the companies having as activity object product design and these companies have to express the cost of designing a single part, in order to calculate the price of this king of service. Thus, the present paper is focused on a possible way of cost reduction, as low cost is considered a universally attractive objective.

» Keywords: selling price, industrial products, designing cost

PDF

Back to Top


  • Cătălin GHEORGHE

SOME ASPECTS REGARDING ECONOMICAL AND FINANCIAL ANALYSIS CONTRIBUTION TO THE BRANCH OF ECONOMICS

» Abstract. The analysis adequate to different considerations represents a method of scientific research having a large domain of utilization: economical, financial, judicial, medical, engineering etc. In the economical field, a new discipline formed and crystallized having different labels, frequently encountered as economical and financial analysis. This scientific method used to study different economical and financial phenomena contributes to develop branch of economics or not? The article comprises many points of views regarding economical and financial analysis contributions and many arguments for its transformation into a scientific discipline.

» Keywords: science, analysis, method, methodology, economics

PDF

Back to Top


  • Cătălin GHEORGHE

WAY OF FINANCIAL CRISIS TRANSMISSION IN ROMANIA

» Abstract. The financial system in Romania evolved in an environment strongly marked by the global financial and economic turmoil. The Romanian economy had reported high economic growth for several years, accompanied by the build-up of a relatively significant external deficit, as well as by the rise in short-term external debt. The banking sector, which holds a key position in the financial system, withstood these pressures well. The repercussions of the deteriorating external economic environment affected the Romanian economy with a certain time lag, adversely affecting above non-financial private sector. The National Bank of Romania, in its capacity as supervisory authority, responded to the new threats by meeting the specific liquidity needs. Measure adopted like strictly monitoring of banks, improve the prudential regulation framework and, signing, together with the Government, financing agreements with the International Monetary Fund and the European Union. These agreements ensure the adequate financing of the current account deficit and render economic and financial policies more credible.

» Keywords: private sector, method, methodology, economics

PDF

Back to Top


  • Adrian GHIONEA, Dumitru CATRINA, Nicolae PREDINCEA, Lidia Florentina PARPALĂ

GENERATION FEATURES OF POLYGONAL AREAS ON LATHES

» Abstract. This paper presents generation kinematics and structure of generating kinematic chains for regular polygonal surfaces processing turned by cinematic or numerical generation. The shape for those faces directory is obtained cinematically as a trajectory of a point or trough motions numerically controlled. Generation kinematics on conventional or CNC, mono or multispindles lathes is analyzed. There are established correlations between motion kinematical parameters and tool and machined surface construction parameters.

» Keywords: polygonal milling, generation kinematics, kinematic chains, multispindle lathe, numerically controlled lathe

PDF

Back to Top


  • Roxana GREJDĂNESCU, Eugen STRĂJESCU, Valeriu AVRAMESCU

CONSIDERATIONS REGARDING THE COMPLEX SURFACES PROCESSING BY USING CNC MACHINE TOOLS

» Abstract. This paper represents a study in the CNC machine-tools' area and on the complex surfaces processing, using these kind of machines. The paper also is based on the development of a virtual model for a CNC multifunctional machine, with large number of axis, for cutting operations. A modular structure, with 8 axis, which is meant to satisfy the requirements of a large processing area, leads to an original new machine with a high performances and a high economical efficiency but also very complex by the integration of some mechanisms and kinematics structures of high complexity. The processing axes combination, the possibility to use various types of tools, the usage of some intelligent gripping and fixing systems, the sensors’ integration, CNC command and active control, seen in adaptive and modular way, allow to the new concept of multifunctional machine to generate complex geometrical surface, surface which is required by the part’s functionality.

» Keywords: CNC machine, complex surface, cutting operations

PDF

Back to Top


  • Petr HRABĚ, Rostislav CHOTĚBORSKÝ, Monika NAVRÁTILOVÁ

INFLUENCE OF WELDING PARAMETERS ON GEOMETRY OF WELD DEPOSIT BEAD

» Abstract. Automatic weld surfacing is being employed increasingly in the process and power industries. Because of its high reliability, all-position capability, ease of use, low cost and high productivity, FCAW has become a natural choice for automatic surfacing. With increasing use of FCAW in its automatic mode, there will be increased dependence on the use of equations to predict the dimensions of the weld bead. Exponential technique to predict the geometry of the weld bead in the deposition of high chromium cast iron onto structural steel S235JR is presented.

» Keywords: weld deposit, weld bead, penetration, width

PDF

Back to Top


  • Izabella ICHIM

EXPERIMENTAL DETERMINATION OF CONNECTING PIPE LENGTH INFLUENCE TO THE DATA ACQUIRED

» Abstract. The utilization of pneumatic muscles in industrial applications is still in a premature stage, due to the relative freshness of these components. The paper presents some of the results of research carried out in the Fluidtronics Laboratory of Department of Economical Engineering and Manufacturing Systems of the Transilvania University of Brasov.

» Keywords: pneumatic muscle, connecting pipe length, pressure, force

PDF

Back to Top


  • Izabella ICHIM

EXPERIMENTAL DETERMINATION OF PNEUMATIC MUSCLE INFLATION AND DEFLATION TIME

» Abstract. Recent research on pneumatic drive elements has yielded the development of a membrane type drive, known as pneumatic artificial muscle. A pneumatic artificial muscle is a contractile and linear motion engine operated by gas pressure. Its concept is a very simple one: the actuator’s core element is a flexible reinforced closed membrane (shell, diaphragm) attached at both ends to fittings (end fittings, closures, clamps) along which mechanical power is transferred to a load. As the membrane is inflated or gas is sucked out of it, it bulges outward or is squeezed, respectively. Together with this radial expansion or contraction, the shell contracts axially and thereby exerts a traction force on its load. The force (tension, load) and resulted motion of this type of actuator are linear and unidirectional. The paper presents some of the results of research carried out in the Fluidtronics Laboratory of Department of Economical Engineering and Manufacturing Systems of the Transilvania University of Brasov. Experiments performed have concerned the determination of muscle inflation and deflation time.

» Keywords: pneumatic muscle pressure, force, inflation time, deflation time

PDF

Back to Top


  • Adela IONESCU, Daniela COMAN

IMPROVING THE BEHAVIOR QUALITY OF EXCITABLE MEDIA PHENOMENA USING RECENT COMPUTATIONAL TOOLS

» Abstract. Nowadays, computational fluid dynamics (CFD) becomes more and more mature. Its software tools are increasing in importance, and constitute a great challenge for the research in this area. A modern area where CFD has large applications is the mixing theory. Since the years ’48, three basic stages were clearly identified in the study of the mixing:
- The entrainment stage – where the large-scale flow structure need to be correctly described;
- The subsequent stirring process (responsible for the interfacial surface generation between the mixing species) – where there is necessary, a correct defined intermediate range of scales;
- The dynamic process – at the smallest scales – this must be captured to describe the molecular mixing process itself.
The mixing problems are still far from complete solving. A recent goal is to find a consistent and coherent theory to stand up that a mixing model in excitable media leads to a far from equilibrium model. In this order, the present paper continues the recent work in the field of computational dynamics, bringing new useful features based on statistical and computational observations. The appliances of the software MAPLE11 are handled and their important applications for the study of the models' behaviour are pointed out.

» Keywords: turbulent mixing, vortic flow, rare event, Maple Assistant

PDF

Back to Top


  • Tudor IRIMIAŞ, Adrian PÎSLĂ

THE CONTRIBUTION OF CHANGE MANAGEMENT ON THE SUSTAINABLE DEVELOPMENT

» Abstract. The work proposes an approach to the issue of the sustainable development through the change management process. The approach to sustainable development through change management is motivated from the fundamental function of an enterprise: making profit. In this case, prosperity is very important from the point of view of the shareholders. Sustainability means in this context the capacity of generating financial value for an undetermined period. The change management techniques and tools contribute to this function through streamlining the detection of a change in the enterprise structure or in the internal or external flows. In the context of sustainable development, the concept of social responsibility is discussed and the importance of ethical and social standards is highlighted. The main topic is about how change management creates a framework for a system for monitoring, comparing and prognosticating the enterprise flows, easing the management actions and contributing to competitiveness, efficiency and sustainability of the enterprise.

» Keywords: change management, sustainable development, social responsibility

PDF

Back to Top


  • Tudor IRIMIAŞ, Adrian PÎSLĂ

THE PRESENCE OF CHANGE MANAGEMENT IN THE SYSTEM MANAGEMENT PROCESSES

» Abstract. The significance of the paper is the creation of a conceptual bridge between the system engineering and the change management process through highlighting the features of the system management. This paper underlines the importance of understanding the company as a continuous changing system and highlights the efficient influence that an appropriate managing system may have on the technological trend. Under these premises of the enterprise seen as a continuous changing system, the change management gained additional attention in research and practice, due to the vast and various changes that occur on a systems’ integrity because of the accelerated technological development. Due to the coexistence of the technical and the managerial area present in the systems of a company, some fundamental aspects of the change management process in system engineering are to be brought into discussion. Whenever a system is designed or a system is being modified, the understanding of change management tools, models and features is fundamental.

» Keywords: change management, systems management, system engineering

PDF

Back to Top


  • John KECHAGIAS, Vassilis IAKOVAKIS, George PETROPOULOS, Stergios MAROPOULOS

Α PARAMETER DESIGN IN TURNING OF COPPER ALLOY

» Abstract. An optimization of the cutting parameters during turning of a copper alloy (GC-CuSn12) using the Taguchi design is attempted. Test specimens in the form of near-to-net-shape bars and a titanium nitride coated cemented carbide (T30) cutting tool were used. The independent variables considered were the cutting speed, feed rate, cutting depth and tool nose radius. An orthogonal matrix experiment (L9(34)) was conducted and the arithmetic mean roughness was measured and optimised according to the process parameters using an analysis of means and an analysis of variances. Finally, an additive model was applied on the experimental results and a verification experiment, using the best combination of parameters, was carried out in order to compare the actual and the predicted values.

» Keywords: turning, surface roughness, optimization, modelling

PDF

Back to Top


  • Vladimir MĂRĂSCU KLEIN

LIFE CYCLE COSTS OF PRODUCTS

» Abstract. The life cycle costing process includes identification of different types of items or methods. The structure of cost items will always depend on the nature of the product and should always facilitate life cycle cost analysis. The present paper is focused on determining the main items that influence the cycle cost and their importance.

» Keywords: life cycle cost, management cost, quality

PDF

Back to Top


  • Vladimir MĂRĂSCU KLEIN, Claudiu COVRIG, Cristina FILIP, Luciana STAN

TECHNICAL–ECONOMIC EVALUATION SUBSYSTEMS ENERGY PRODUCTION SYSTEMS WITHIN THE LIGHT PARAMETER "ENERGY INTENSIVE"

» Abstract. The selection of the system’s efficiency parameter as an essential technical one, having a major influence over the production system is justified because it directly influences the costs of the PS products, the PS expenses with energy and the technical efficiency of the production system. The efficiency is a parameter that differs from one system to another and represents an important element taken into consideration in the moment of adoption the investment decision.

» Keywords: evaluation, energy, efficiency parameter, production system

PDF

Back to Top


  • Jan KRMELA, Miroslav MÜLLER, Vladimíra TOMANOVÁ, Soňa RUSNÁKOVÁ

USING OF COMPUTATIONAL MODELLING TO LONG-FIBRE COMPOSITE

» Abstract. The article deals with using the computational modelling to long-fibre composite structures with an elastomer matrix. These structures are included into tire for transport means e.g. radial tire for passenger vehicle as steel-cord belt plies. If good approach will be applied to the computational modelling of tire composite parts then good results are obtained. The good models must include all necessary inputs as geometry, material parameters of reinforcement and elastomer matrix, loading conditions etc. Then models represent actual states of composite structures, used in automobile tire-casing. The attention will be paid to the steel-cord belt plies which are composite structures with elastomer matrix and reinforcing steel-cords. The outputs from the computational modelling of tire long-fibre composite will be using as inputs to the computational modelling of the tire as whole.

» Keywords: composite, long-fibre, tire, FEM

PDF

Back to Top


  • Jan KRMELA

THE COMPUTATIONAL MODELLING OF TIRE

» Abstract. The article deals with the computational modelling of the strain-stress analyses of radial tire for passenger vehicles. The Finite Element Method (FEM) using the program system ANSYS is applied to the computational modelling. The tire is complicate composite structure which consists of textile-cords, steel-cords and elastomer parts of tire carcass. For computational modelling of tire is necessary knowledge about experimental modelling of tire from macrostructure and microstructure.

» Keywords: tire, FEM, strain-stress analyse

PDF

Back to Top


  • Georgiana LIMBĂŞAN, Ion TUREAC

CONSIDERATIONS UPON THE POSSIBILITIES OF APPLYING THE VALUE ANALYSIS METHOD IN MANUFACTURING ROLLING CONTACT BEARINGS

» Abstract. Applying the studies of value analysis in the framework of manufacturing simple components or sub-assemblies of complex products raises several difficulties, especially due to the necessity of observing the principle of systemically approaching the utilization value. In the particular case of applying the value analysis method in manufacturing bearings, the difficulties are generated by the diversity of the technical products wherein they are to be used and by lack of knowledge upon the functions that they are to fulfil in the assembly they are to be integrated within, during the moment of their design and manufacturing. The paper herein presents the stages to be gone through in order to achieve the value analysis studies in the case of bearing manufacturing and there is exemplified the manner in which there may be identified the functions of the products undergoing the value analysis study, in the case of bearing manufacturing. There are likewise forwarded the authors’ considerations as regards the necessity for including a new condition which is to be fulfilled in the case of bearing manufacturing and utilization: the environmental condition. We deem that only simultaneously observing the requirements of all parties involved: users, manufacturers and environment may ensure for the products in which there are integrated bearings, a utilization value correlated with the environment requirements.

» Keywords: value analysis, bearing manufacturing, environmental condition

PDF

Back to Top


  • Georgiana LIMBĂŞAN

APPLICATIONS OF VALUE ANALYSIS WITHIN BEARING INDUSTRY

» Abstract. The method of value analysis aims at achieving the functions of the product requested by the user so that there should be proportionality between the usefulness of every function and the consumption of means necessary for its achievement. The article herein synthetically submits a case study upon applying the method of value analysis to products from bearing industry, as well as the results obtained following the analysis.

» Keywords: value analysis, conic roller bearing, bearing manufacturing

PDF

Back to Top


  • Miroslav MÜLLER, Jan KRMELA, Juraj RUŽBARSKÝ

INFLUENCE OF ADHESIVE BONDED SURFACE TEXTURE ON ADHESIVE BONDING PROCESS

» Abstract. Laboratory experiments deal with an influence of a grit-blasting by means of corundum grits AL2O3 of different sizes on a surface roughness of steel substrates prepared according to the standard CSN EN 1465. The experiments considered not only the grain size of a grit-blasted medium (F14, F24, F40, F80 and F100) but also the grit specific size of a main fraction specified by the standard FEPA "F" 42-D-86 which can cause a relief irregularity of the grit-blasted surface, influence the roughness and consequently the adhesive bond strength. Two parameters of the surface texture set by the standard CSN EN ISO 4287 were evaluated: Ra, Rz and their mutual relation Ra/Rz. The results showed that the percentage of the grit specific size stated by the standard is the lowest at the grain size F80 (56.5% of measured grits) and the highest at the grain size F24 (77% of measured grits). Further, a significant falling course of the roughness parameters values with the increasing grain size of the grit-blasted medium was found out. The grit-blasting by means of the artificial corundum of the grain size F24 was chosen as the most suitable adhesive bonded steel substrate surface treatment.

» Keywords: surface roughness, adhesive bonding, grain size, grit blasting

PDF

Back to Top


  • Gabriel MUNTEANU, Adrian GHIORGHE

A COMPREHENSIVE STATIC AND MODAL ANALYSIS OF "5R" KINEMATIC CHAINS USING VIRTUAL TECHNIQUES

» Abstract. An important characteristic for the field of industrial robotics is the positioning precision of end effectors. Due to the progress of the computer technologies and control systems, the accuracy has significantly improved in the last years. Still, there is a continuous need for machines to provide higher accuracy mechanisms and kinematic chains or to adjust the systems already built in order to adequate it to reach to a better precision of the tasks. The current paper shows the results of a comprehensive analysis applied for RRR-RR robotic system already build including two versions of static analysis and modal analysis, using the modern virtual instruments. The main stages pursued was: design of the mechanisms and kinematic chains for each rotation joint, in accordance with the real robot, modelling of the connections and the mesh for each element and surface, simulation and model analysis using FEM specialized instruments. A final indication about the characteristics to improve is presented.

» Keywords: accuracy, stiffness, FEM, static analysis, modal analysis

PDF

Back to Top


  • Lavinia Nicoleta NEAGOE, Vladimir MĂRĂSCU KLEIN

EMPLOYEE SUGGESTION SYSTEM (KAIZEN TEIAN) THE BOTTOM-UP APPROACH FOR PRODUCTIVITY IMPROVEMENT

» Abstract. In a globalization environment, the organizations’ competitive advantage is determined by the products’ cost/quality ratio which is in direct correlation with the employees’ knowledge, attitude and commitment, at all the levels of the company. The creative ability is present in everyone, needing only to be developed through adequate and accessible systems, known as Employees Suggestion System (the English interpretation of Japanese system name: Kaizen Teian). This article aims to give the essential guidance in order to draw up and implement such a system that helps develop the motivation and creativity of all the members and a bottom-up approach for productivity increase of each organization. Based on Japanese and Western countries experiences, are presented the potential areas of improvement, how to encourage people to participate and work, motivating tools and awards, review and evaluation possibilities. An implementation model is presented. In the last part, as result of ten years of experience in this field of activity in Romanian companies, are presented the key points for a good implementation.

» Keywords: suggestion system, Kaizen Teian, employees’ involvement, continuous improvement, cost saving

PDF

Back to Top


  • Cristina Ileana PASCU, Iulian POPESCU

RESEARCH ABOUT ROUGHNESS FOR MATING MEMBERS OF A CYLINDRICAL FINE FIT AFTER TURNING WITH SMALL CUTTING FEEDS

» Abstract. In this paper the turning with small cutting feeds for a shaft and bore of a fine fit has been studied experimentally. It has been measured obtained roughness Ra, Rz, Rq and has been correlated with shape of chips and their plastic deformation. In range of very small cutting feeds, the plastic deformations have a much higher influence on roughness than for normal or great values of cutting feeds. In range of small cutting feeds, some disturbances ratio geometrical roughness appear because of phenomena from plastic deformation in cutting area. Also, appear elements of chips that make uneven into geometrical flutes generated by cutting tool and, thus, the measured value of roughness is non-uniform. Viewing under microscope of micro-asperities of surfaces allowed finding explanations about measured values of roughness parameters. It has been measured the roughness after turning with small cutting feeds for shaft and bore and these have been correlated with plastic deformation phenomena. They are presented microscopic images of surfaces and chips, calculated results and diagrams, tables with final results and diagrams of roughness depending on cutting feed values for small cutting feeds range. Conclusions will show the advantages and disadvantages of using small cutting feeds.

» Keywords: roughness, clearance fit, turning

PDF

Back to Top


  • Ioana PETRE, Tudor DEACONESCU

ISOKINETIC EQUIPMENT DESIGNED FOR THERAPEUTIC EXERCISES

» Abstract. The paper presents a type of isokinetic equipment that achieves continuous passive rehabilitation movements as part of the recovery program of patients with post-traumatic disabilities of the bearing joints of the inferior limbs. International studies have revealed that the deployment of equipments capable of performing continuous passive motions for rehabilitation purposes has contributed to diminishing rehabilitation costs by about 50%. For these reasons, a relatively short resting period needs to be followed by isokinetic motions, subsequently continuous passive, then assisted active and eventually unassisted active. The necessity of conceiving isokinetic equipment required for therapeutic exercises results from the high incidence of patients suffering from posttraumatic dysfunctions of the lower limbs. The equipment is actuated by pneumatic muscles and utilizes compressed air as its energy source in order to ensure complete absorption of the end of stroke shocks and minimizing user discomfort. Although the utilization of pneumatic muscles in various industrial applications is still in an early phase, due to the relative newness of these components, it is soon to become a feasible alternative for the electro-mechanically actuated systems.

» Keywords: isokinetic equipment, pneumatic muscle, rehabilitation

PDF

Back to Top


  • Ioana PETRE, Dan PETRE

STUDIES ON THE APPLICABILITY OF THE PNEUMATIC MUSCLE IN INDUSTRY

» Abstract. The evolution underwent by the technology during the last decade facilitated utilization of pneumatic muscle in many applications, particularly in the field of industrial robots. The pneumatic muscles are lightweight actuators, able to generate high torques at low and moderate speeds, able to be connected to the structure without gearing, having a natural compliance and shock resistance and a possible autonomous operation. The current paper will focus on the pneumatic muscle with it’s applicability in the industry .The paper presents also one possible application for pneumatic muscle which is isokinetic equipment designed for therapeutic exercises and it’s functionality. The isokinetic equipment allows recovery exercises of the hip and knee joints, the lower limb being immobilized in the device. Completed research has proved that the utilization of such equipments would significantly reduce the period of recovery, the patients resorting to a smaller quantity of pain medication. Although the utilization of pneumatic muscles in industrial applications is still in an early phase, because the relative newness of these components, it is soon to become a feasible alternative for the electro-mechanically actuated systems.

» Keywords: pneumatic muscle, actuators, isokinetic equipment

PDF

Back to Top


  • George PETROPOULOS, John KECHAGIAS, Vassilis IAKOVAKIS, Stergios MAROPOULOS

SURFACE ROUGHNESS INVESTIGATION OF A REINFORCED POLYMER COMPOSITE

» Abstract. The influence of cutting speed and feed rate during turning on the surface roughness of a glass fiber polymer composite (Ertalon 66 GF-30) was experimentally investigated. Test specimens in the form of bars and a P20 cemented carbide cutting tool were used while the cutting depth was kept constant during the experiment. Parameter design using an orthogonal matrix experiment was conducted and the experimental results were analysed using an ANOM and an ANOVA analysis approach. Based on the statistical analysis of the experimental results it was found that the arithmetic mean roughness depends mainly on the feed rate parameter.

» Keywords: turning, robust design, parameter design, arithmetic mean roughness

PDF

Back to Top


  • Corina POP, Gabriela MAILAT

RADIO FREQUENCY TECHNOLOGY IN LIBRARIES

» Abstract. Modern libraries have undergone significant changes in the process of introducing advanced computer and communication technologies. RFID (Radio Frequency Identification) systems were adopted by many libraries in the last years due to their advantages in comparison with barcodes. One most important advantage consists in the increased amount of information that can be stored and processed for specific purposes. Libraries use RFID systems for book identification, self-checkout, antitheft control, inventory, book circulation. All these contribute to more efficient library services in terms of reduced labour costs, better document management and collection record.

» Keywords: barcode, RFID, library

PDF

Back to Top


  • Iulian POPESCU, Cristina Ileana PASCU

AESTHETIC SURFACES BASED ON EPICYCLOIDS AND ORTHOCYCLOIDS, GENERATED BY VIBRO-ROLLING

» Abstract. In this paper are presented the procedures at vibro-rolling by which can be obtained surfaces that have flaws with regular forms with particularly aesthetic appearance. These surfaces may be exterior surfaces of some products, such as should be aesthetic, too. For surfaces in contact with relative motions certain relief’s benefit lubricant penetration. Processing by vibro-rolling allows obtaining surfaces with particularly shapes but with some flutes that permit easy penetration of lubricant. For achieving this study, the epicycloids and orthocycloids generation principles and the turning process possibilities are used. Kinematics generation of some elongated epicycloids and orthocycloids allow the approximation of some sections for pieces turned processed. Using the method of generation by epicycloids is advantageously because decreases the processing time for some gross production pieces. The established relations permit the designing of such devices. The experimental model permitted the testing of theoretical views. This paper presents the adequate relations for designing and they are provided examples. In addition, it is verified the solutions by means experimental model.

» Keywords: vibro-rolling, orthocycloid, epicycloids, aesthetic surfaces

PDF

Back to Top


  • Maria POPESCU, Simona LACHE

ENTREPRENEURSHIP IN UNIVERSITY

» Abstract. The entrepreneurship - concept known for over two centuries, is extensively promoted in academic and business environment in the last decades, as a key factor of the competitiveness and economic growth. In a broader sense, the entrepreneurship defines a behaviour characterized by the emphasis on innovation, on the creation of new business or to make changes in existing organizations in order to obtain useful results. Initially applied in business, entrepreneurship is present today in all spheres of economic and social life, materialized through all kinds of projects: for disadvantaged regions, humanitarian and environmental projects etc. Based on these general considerations, the paper aims presenting relevant aspects of academic entrepreneurship, with emphasis on the relationship between entrepreneurship and modern management systems implemented for quality assurance in university education and research.

» Keywords: entrepreneurship, entrepreneurial university management, quality and innovation in education and research

PDF

Back to Top


  • Maria POPESCU, Mircea NEAGOE

ENTREPRENEURSHIP IN UNIVERSITY RESEARCH

» Abstract. In relation with the increased role of research in the context of the knowledge-based society, the paper deals with the development of the entrepreneurship in university research. Initiating new business or improving performances in various areas of economic and social life through the application of the research results can be seen as ways of achieving progress, very important considering the impact on the society evolution. In this context, the development of the entrepreneurship has become a key factor which influences the final results of research, development and innovation cycle, obtaining useful effects more efficient and faster. The paper examines the connection between entrepreneurship and university research valorisation, and aims presenting three relevant issues: increasing role of university research in knowledge-based society; modern ways of transferring results of the university research and the role of entrepreneurship in the successful completion of technology transfer; university spin-offs and the main entrepreneurial activities of their implementation process.

» Keywords: entrepreneurship, university scientific research, technology transfer, university spin-offs

PDF

Back to Top


  • Rosa Maria RIO-BELVER, José Maria BERENGUER, Zuriñe GOMEZ DE BALUGERA

RE-ENGINEERING THE KNOWLEDGE MANAGEMENT PROCESS. THE CASE OF THE UNIVERSITY COLLEGE OF ENGINEERING

» Abstract. This paper describes the Re-engineering applied to a process entitled "Knowledge management KMP" pertaining to a University College of Engineering. The principles of process re-engineering are applied to an organization managed by processes according to the EFQM - European Foundation Quality Model - in order to increase its efficiency. Specifically, we worked by following the steps within an improvement cycle called CMP (Business Process Improvement Cycle) and by using a value analysis tool to quantify its value and improve efficiency.

» Keywords: re-engineering, knowledge management, business process management, engineering higher education, innovation

PDF

Back to Top


  • Yanko SLAVCHEV

SOME ASPECTS OF THE LIFTING DYNAMICS OF FORK LIFT TRUCKS

» Abstract. A research with 3D computer models on some aspects of the lifting dynamics of triple telescopic lifting gears is presented. The influence of the lifting tackle mechanisms, moving masses, etc. is taken into account. Contacts between chains and tackle rolls are also accounted for and it introduces various complexities to the model. Precise setting of integrator parameters enables the simulations to realize various model beneficial options such as: lifting for a given start time, lifting and stopping, lifting load with and without impact as well as accounting for the contact forces.

» Keywords: lifting gear, chain, lifting dynamics, impact, contacts, stiff problem

PDF

Back to Top


  • Galina TODOROVA, Valentin DIKOV

RELIABILITY OF THE FEM CALCULATIONS OF THE FRACTURE MECHANICS PARAMETERS

» Abstract. This paper describes some results obtained by analyzing cracked plates by means of FEM based on the procedures of ANSYS 10. The numerical results are compared with their analytical solution. The influence of mesh configurations on crack characteristic values is considered. It is found that the simple isoparametric elements are not appropriate for calculating SIF and their usage has to be avoided. ANSYS gives fictitious results about KII and they must be neglected.

» Keywords: linear fracture mechanics parameters, Stress Intensity Factors (SIF), FEM, ANSYS

PDF

Back to Top


  • Marian Nicolae VELEA, Simona LACHE

THERMOPLASTIC SANDWICH FORMING - NUMERICAL AND EXPERIMENTAL RESEARCH

» Abstract. The forming of sandwich structures in complex three-dimensional shapes represents a big challenge. The purpose of the present work is to examine, using a validated numerical model, the deformation and some failure modes of a sandwich structure that occur within a forming process. The Econcore’s Thermhex® honeycomb core with PP skins, developed at K.U. Leuven, has been used along this investigation. The validation of the numerical model has been done by correlating the results obtained from four-point bending experimental tests with those obtained by four-point bending simulations. The properties of the material from the FPB simulations that give the best correlation with the experimental tests are further used in the forming simulation. The results have proven that the predominant deformation mechanism is out-off-plane shearing due to the localized forming forces. The structure fails due to very high shear stresses. A solution to improve the forming process for this type of structure may be the use of non-rigid die or punch tools.

» Keywords: sandwich structure, forming process, thermoplastics materials, FE simulation

PDF

Back to Top


 

Home ] Up ] For Authors ] Peer Review ] Board ] Indexing ] Site Contents ]