Analele Universităţii
"Eftimie Murgu"
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                                                            Issues > Archive > 2007
 
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Anul XIV (2007), Nr. 1

 
The Origin of Vibration Redemption Effect for Shape Memory Alloys
Daniel Amariei , Ion Vela , Gilbert-Rainer Gillich

Shape memory alloys (SMA) components can affect through two mechanisms the vibrations of structures. The stresses from a SMA element that realize phase transformations, as a result of vibrations, have an effect on the frequency-amplitude characteristics. In addition, a dissipation of energy due to hysteresis in a SMA element can reduce the natural frequency and affect forced vibrations.

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Analysis and Design of Thermal Actuators
Daniel Amariei, Yvan Meason, Ion Vela

Current literature describes the use of multiple SMA elements placed in parallel to increase the lifting capabilities of an SMA actuator, which however, is limited to springs of like-diameter. A constrained optimization problem was formulated, with constraints on the maximum number of springs, voltage applied, and SMA spring length and cross sectional area for the development of an optimal SMA actuator that will be able to apply maximum force.

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The Simulating of Systems with Discreet Events
Olga Ioana Amariei , Constantin Dumitrescu , Raul Maloş

The simulation of discreet events is one of construction ways of models, so that to be observed the dynamic behavior of systems. There is many conventional methods in realizing some simulated models. In experimental faze, those models are executed for a enough period of time that could generate results. The obtained results are used for studying the evolution of system and are base for the late decisions.

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Forms and Methods of Promoting the Participative Management in the Organization
Solomia Andreş

The following paper presents the most practical and modern methods and forms of promoting the participative management in the organization. It also gives some theoretical and practical conclusions regarding the long period of transition in which this type of management has improved.

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Methods for Raising the Level of Motivation Management Based on Major Projects
Solomia Andreş

The paper presents one of the most modern methods of increasing the level of motivation and of training the personnel for solving the complex problems which appeared in the period of changes. These problems request the implication of a large number of experts.

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Instrumentation and Measuring of the Cutting Forces Presentation
Cornelia Victoria Anghel

In the paper the SUCTRONIC25 machine and the Fx , Fy , Fz cutting forces are described. A dynamometer capable of measuring forces in 3 directions can be used to measure cutting forces. In the example the composite has been turned at 100, 200 and 400 [m/min]. The numerical results are illustrated above.

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Experimental Results for the Cutting Forces on a Considering Piece
Cornelia Victoria Anghel

The paper presents the results for the cutting forces. There are illustrated some diagrams where the corelation between the cutting forces and Ra are presented. The diagrams for the roughness of the piece wich has been cutted having the cutting speed 100[m/min], 200[m/min] and 400[m/min].

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Reliability and Maintenance of Industrial Equipment
Viorel Ionut Bizau , Constantin Marta

Itís necessary a definition and understanding of the reliability and maintenance notion, a case of the dialectical relation, in time, as a necessity to reach of a higher share of profitableness.

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Simulation of the Dynamic Behavior of an Asynchronous Machine Using Direct Self-Control
Cristian Paul Chioncel , Petru Chioncel , Marius Babescu , Nicoleta Gillich

The paper presents the major steps that have to be gone for the implementation of the mathematical model of the asynchronous machine in SciLab / Scicos. This implemented ASM model, will be used to check the dynamic behavior of the system, the current diagrams as well as the behavior motor speed and the torque, if the input signal has a pulsation form. This implementationís are made in Scilab / Scicos environment, a clone of the MATLAB, which provides number-crunching power similar to MATLAB, at a much better cost/performance ratio. The implemented model offers the possibility to analyze the behaviors of the asynchronous machine in different dynamic situations: speed, torques, current in motor or generator regime and to study its behavior in different possible control schemes.

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Study of the Photovoltaic Potential from the Location Resita
Cristian Paul Chioncel , Thomas Nierhoff , Petru Chioncel , Gillich Nicoleta , Florin Berinde

The present paper wants to be a first contact in analyzing and knowing the solar photovoltaic potential from Resita, this, in fact means, the 45 parallel in our country. This issue will be obtained through monitoring the produced electric energy and injected in the public grip. The research studies are extended over a period of two years to have a more exact evolution of the monitories parameters. These researches results will be then directly used in planning of photovoltaic plants in our country.

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Relations between Communities of Practice and Innovation Processes
Jeanina Biliana Ciurea

The paper makes an empirical and theoretical contribution to the innovation literature by both examining case study evidence from a number of technological innovation projects, and reflecting on the relationship between innovation processes and communities of practice. It is concluded that this relationship is not unidirectional. Not only did the communities of practice influence the innovation processes, for example through shaping important knowledge sharing processes, but the innovations also impinged on organizational communities of practice in important ways. The paper also proposes ways in which the analytical utility of the community of practice concept can be improved, for example by taking greater account of potential negative effects that communities of practice can have for innovation processes.

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Planning and Computerised Monitoring of an Experiment of Thermal Analysis of the Alloys in the Al-Cu-Si System
Florentina Cziple

The paper presents an installation conceived for the automatic registration of the temperature in the thermal analysis, at the industrial and laboratory level, with application to the system of non-ferrous alloys Al-Cu-Si. The experiment performed on the above installation is compared to processes monitored through simulation with specialised software

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The Prognosis of the Phase Equilibrium Diagram of the System Al-Cu-Si
Florentina Cziple

The paper presents a model for establishing the mathematical functions of the liquidus and solidus curves, from the binary diagrams Al-Si, Si-Cu, Cu-Al and their use in the prognosis of the phase equilibrium diagram from the ternary system Al-Cu-Si. We have studied the model of the non-ideal liquid solution of the regular type. The calculus and graphic plotting of the equations for the binary systems has been performed on the computer

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Loading Processes Dynamics Modelling Taking into Account the Bucket-Soil Interaction
Carmen Debeleac

The author proposes three dynamic models specialized for the vibrations and resistive forces analysis that appear at the loading process with different construction equipment like frontal loaders and excavators. The models used putting into evidence the components of digging: penetration, cutting, and loading. The conclusions of this study consist by evidentiate the dynamic overloads that appear on the working state and that induced the self-oscillations into the equipment structure

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The Flexibility of a SFF
Constantin Dumitrescu , Olga Ioana Amariei , Raul Maloş , Viorel Bizău

The flexible production systems have appeared due to the necessity of exigencies and performances growth of small and medium series production (even unique parts production). Their development represents the result of a more than 100 years of evolution, consisting in an answer way to the mutations appeared in the economical medium in which they activate.

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An Analysis about the State of Stress in a Railway Axle
Eugen Ghita , Gilbert-Rainer Gillich

The paper deals with a finite element analysis about the state of stress and deformation in a driving railway axle or shaft. The stress - displacement analysis has been performed with the Algor and Ansys softwares, two powerful finite element analysis tools. There were especially analyzed the freeting areas between the axle and the driving gear or the rolling wheels and the contact areas between the rolling wheels and the rail.

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Study on the Solidification of Grey Irons, by the Drawing of the Cooling and of the Contraction Curves
Cincă-Ionel Lupinca

This paper presents the study of the solidification of hypoeutectic grey irons using a computer registration system for the setting of the cooling and of the contraction curves and for the determining of the parameters of the two curves and their secondaries. This study focuses on the obtaining of the solidification results for grey irons produced in induction electric furnaces using different types of metallic charges.

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The influence of the metallic charge on the solidification of grey irons
Cincă-Ionel Lupinca , Constantin Marta

The influence of the metallic charge on the shape and on the distribution of the lamellar graphite leaks in the metallic the matrix, represents a very important clue in the modified (with FeSiSr) and of the unmodified grey irons solidification, obtained in an electric induction furnace of medium frequency (8000 Hz) and with a capacity of 8 kilos.

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Screw-Nut Robotized Assembling
Călin Micloşină , Raoul Avasiloaie

At present, industrial robots are frequently used in assembling operations. This paper presents a simple screw-nut assembling performed by a robotic arm with a 2-finger gripper

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About New Method for Real Mechanical Systems Transmissibility Evaluation
Silviu-Marian Nastac

In this paper the author present some theoretical considerations about a new method for real mechanical systems transmisibility evaluation. This method are based on the classical theory of transmisibility evaluation, that suppose the real mechanical systems composed by a lots of elements, and each element adding an additional degree of freedom to the system. The proposed method suppose two way for global transmisibility evaluation: in first case it is supposed that the inputs and the transfer functions of the system are known, and the second case when the inputs and the outputs of the system are known. The final result of this method is a global transmisibility value, that are taking into account both the input signal composition of frequencies, and the transfer characteristics of the analized system.

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Computer Aided Design of an Admission Valve with Autodesk Inventor
Dorian Nedelcu

The paper presents the steps for 3D computer aided design (CAD) of an admission valve made by Autodesk Inventor.

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Stress Analyse of an Admission Valve with Finite Element Method
Dorian Nedelcu

The paper presents the stress analyses of an admission valve made Cosmos Design Star software. The 3D geometry was generated in Autodesk Inventor

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Some Aspects Concerning Convective Circulation Mode of Heat Transfer in Furnace to Wood Heat Treatment
Nadia Potoceanu

The paper presented the most aspects of convective circulate mode of heat transfer: heat transfer through the boundary layer formed at the surface of the heat generator; heat transfer in the heat carrier and heat transfer through the boundary layer formed at the heated surface

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The Synthesis and Analysis of Partial Discharges from Stator Winding Insulation of Hydro Generators
Mihaela Răduca , Ana-Maria Pittner , Eugen Răduca , Iancu Tătucu

In this paper to perform the partial discharges which appear in stator winding insulation, the main characteristic measures of these, measurement and the results of partial discharges test

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The Influence of Metallic and Non-Metallic Inclusions on the Characteristics of Non-Ferrous Alloys Al-Si
Rodica Rădulea

This paper presents on experimental study which highlights the influence of metallic and non-metallic inclusions on the mechanical characteristics of, AlSi12 and AlSi10Mg alloys

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Temper Fragileness Study for RUL 2 Steel
Rodica Rădulea , Cincă-Ionel Lupinca

This paper presents an experimental study about the tenacity variation depending on the tempering temperature of the steel RUL2 grade, within q wide range of temperatures. By this analysis it is possible to study the cooling of the above mentioned heat treatment on the temper fragileness

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Business Parks - Theoretical Background
Venera Cristina RÓndaşu

Economic activities can take place in either a physically scattered manner or in proximity. Companies in physical proximity in a designated area form the business parks. A business park is a site that is designed for economic activities in the field of trade, industry and different commercial activities (IBIS 2002b) Business parks are agglomeration of companies in physical proximity. These features provide certain benefits. Local authorities favor the establishment of business parks to ensure intensive use of land and create strong business environments in their localities. In the private sector, companies receive various benefits from being part of the B. P. First, the agglomeration factor leads to decreased costs for common maintenance services. Secondly, parks with companies in similar sectors benefit from joined marketing activities and increased exposure. Thirdly, B.Ps embodies conditions for synergy between companies. Synergy can be based on activities such as sharing and exchanging of materials and streams, professional knowledge and expertise, etc

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Comparatives Determination of Thermal Field in Welded Components
Lenuţa Suciu , Iancu Tătucu

This paper presents thermal field variation from the welded components considering electrical arc welded as moving source, with the help of the modelling and simulation software Ansys, and the comparison of simulated sizes with those resulting from the experimental determinations

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Simulation Methods in the Contact with Impact of Rigid Bodies
Cristina Basarabă-Opritescu , Ilie Mihai Toader

The analysis of impacts of elastic bodies is topical and it has many applications, practical and theoretical, too. The elastic character of collision is put in evidence, especially by the velocities of some parts of a particular body, named ďringĒ. In the presented paper, the situation of elastic collisions is put in evidence by the simulation with the help of the program ANSYS and it refers to the particular case of the ring, with the mechanical characteristics, given in the paper

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