Anul XVI (2009), Nr. 1
Researches Regarding the Effect of Nitinol Vibration Damper Applied to Infrastructures
Gilbert Rainer Gillich,
Many of the performed researches all around the world aim to develop advanced technologies in order to enhance the performances of the infrastructure systems, different from the actual ones, fact which involves multidisciplinary research (IT, sensoring, electronics, smart materials and others), aiming to assist engineers in realizing full benefits of structural health monitoring. The paper presents a preliminary feasibility study of a system that can be used for damping of structural vibrations. Thus, shape memory alloys (SMA) components can affect through two mechanisms the structure's vibrations. 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.
Keywords: vibration, dampers, shape memory alloys, infrastructures, frequency
Contribution to Shape Memory Alloys Actuated Systems Design
Gilbert Rainer Gillich,
Even it has been recognized that Shape Memory Alloys have a significant potential for deployment actuators, the number of applications of SMA-based actuators to the present day is still quite small, due to the need of deep understanding of the thermomechanical behavior of SMA. SMAs offer attractive potentials such as: reversible strains of several percent, generation of high recovery stresses and high power/weight ratios. This paper tries to provide an overview of the shape memory functions. A table with property values for different properties of shape memory alloys is also included.
Keywords: Shape memory, modelling, actuation, thermo mechanical transfer, Nitino
Analysis and Behaviour Understanding of a Production System
Olga Ioana Amariei,
Constantin Dan Dumitrescu,
In production systems modelling usually acts to system simulation by discrete events. The present paper exemplifies this, using the Queuing System Simulation module of the WinQSB software.
Modern Approaches of the Management of Remuneration
The study is a systematical approach on remuneration and on its management in the domain of the human resources management, trying to identify the main variables with decisive influence in setting the minimal and maximal limits of remuneration, competences and the managerial art of administrating the remuneration system in the context of continuous law changes.
Keywords: management, remuneration, human resources
The Power Stakes Between those who Finance it- The New Managerial Models
The paper presents the conceptual background and aspects concerning the governing that means the system by which the organizations are leaded and controlled, covering the ensemble of dispositions that allow the insurance that the objectives wanted by the managers are legitimate and the means put to work are adapted to reach these objectives. Considering that the presented models (Stareholder and Stakeholder) are stakes of power between those who lead and those that finance the organization, the convergence of the European and international governing models and systems that involve the existence of some superior governing models, economically, socially and political efficient, the approach of these issues presents special interest being a challenge to Romanian economy. The globalization gives a plus to the convergence - pleading for the Stareholder model and the cultural differences plead for the resort to one of the Stakeholder model's variants.
Keywords: ownership right, enterprise, agencies, governance, control
E-Campus using Open Source
This paper presents the benefit implementing a modern electronic platform for education into high school. Using the new IT technologies and web based learning portals contribute to efficiency the training and study.
Internet and E-Marketing Technology
Traffic on the Internet is growing so rapidly that many companies have troubles in maintaining pace with the demands of visitors of their Web site. One of the most important usage of the Internet is, of course, in electronic business. Internet is consisted of computer and communication technologies, and makes our work easier, because the information are becoming permanent and easily accessible, wherever they are in the world, which provides easy and afordable international presentation for individuals. This significantly changes the ways of conducting business. Is the site easy to use, if the site works properly, which are the standards for online customer service, how to deliver physical products, and the like, is a key issue in e-marketing, ie. how to achieve customer satisfaction with the usage of e-marketing.
Keywords: Internet, Web marketing, e-marketing, organization
Method's and Test Stand for Electronic PID Controller
Cristian Paul Chioncel,
The paper presents method's and a testing stand for electronic controller using for this a signal generator and a digital oscilloscope respectively the virtual instrumentation and the signal acquisitions from the controllers input and output through an data acquisition board and an PC on that Lab View program runs.
Keywords: PID controller, acquisition board, test stand
PID Controller with Operational Amplifier
Cristian Paul Chioncel,
The paper presents a PID controller made with LM741 operational amplifier that implement the PID controllers laws and allow for a wide range of applications of in the field of automatic control of technical processes and systems.
Keywords: PID controller, operational amplifier
Performance of a Grid Connected Photovoltaic Plant
Cristian Paul Chioncel,
The paper presents an overwiev of the performances of the grid connected photovoltaik plant at the University "Eftimie Murgu" Resita, Romania realised on the monitoriesed wheather and installations data stored in a on-line data base during one year.
Keywords: grid connected photovoltaik plant, monitoring system, solar radiation, yield factor
Contributions on Computer Aided Manufacturing of Drill-Jig Bushings
Lata Mirela Violeta,
The paper presents the steps for computer aided manufacturing (CAM) of the bushings technological class parts: design of the part in CAD software; generation of the parametrical link with MSExcel files; extract of the useful information for the technological design (mass, volume, surfaces); setting of the CNC lathe and necessary tools; programming of the CNC code for manufacturing. Given the large variety of the bushings shapes and dimensions, the application focused on the jig bushings used in drilling processes.
Keywords: CAM, CAD, jig bushings
Knowledge Management and Changes Management In University Libraries
The knowledge economy is a new concept that has appeared world wide in recent years. As a sub-discipline of the knowledge economy, knowlege management is a completely new concept and method of management. In this environment libraries becomes more significant. The conventional functions of a library are to collect, process, disseminate and store information and documents in order to provide services for the society. In the knowledge economy era, the library will become a treasure-house of human knowledge. Knowledge management is an important business concept, incorporated in the business and organizational culture as serious participant in the world market. Since the modern consumer or customer service expect high quality products and services, it is necessary that the entities - the same bidders have timely information, knowledge and techniques required for the better serving their customers. Knowledge management systems are systems based on the information technology, which enables participants in the market knowledge and continuous learning. Among the participants in the market are academic institutions, universities, as providers of educational and pedagogical services.
Keywords: knowledge management, changes management, library
Trends in Technology Use
This study aims to investigate the relationship between the use of technology, working conditions and the health and well-being of workers in Europe. As it is known that characteristics of work organisation may reinforce or impair both positive and negative effects of technology use, the role of these characteristics is also considered in this study. The research will provide an insight into the trends and changes in technology use and working conditions in European countries. It also aims to outline the processes that are currently taking shape, as well as to identify the opportunities and threats within the emerging trends.
Keywords: trend, technology, computer, machine
Electrochemical and Optical Method for Analysing the Metallic Layers Deposited on ABS-Type Polymers
The paper presents optical and electrochemical methods of analysis in view of studying the metal layers deposited on the surface of ABS plastic materials. We used optical microscopy in order to observe the quality of the deposits on the surface of polymers, as well as the study of the influence of different factors on the metallisation process. Moreover, we realised also the electrochemical study of the metallic layers deposited on the ABS polymers through the interpretation of the polarisation curves in view of observing the main phenomena occurring on the surface of the polymers.
Keywords: ABS polymers, conductibilised plastic, electrochemical
Chemical and Electrochemical Metallic Covering of ABS polymers
Nicolae Vaszilcsin, Bobina Marian, Mirela Barbu
The aim of this paper is the deposition of metallic layers on the surface of ABS plastic material, by means of two consecutive procedures, namely: the first is represented by the conductibility through chemical or electro-chemical metallic covering of the polymeric support and the second procedure is the electrodeposition of the metal through galvanization. The chemical mehtod consists in the submission of ABS polymers to some conductibility operations of the plastic material surface through chemical copper plating (chemical roughing, degreasing with ultra-sounds, chemical sensitivation, activation and proper conductibility of the material surface). The electrochemical deposition of nickel was made on the plastic material activated in the mixture solution of graphite with potassium carbonate.
Keywords: galvanization, metallic covering, ABS polymers
Use of Technology in the European Union
Technology today plays a central role in European workplaces. It not only enables the direct production of goods and services, but it also facilitates communication and innovation. Given that innovation is one of the main pillars of the knowledge-based economy, and that Europe has committed itself to becoming the most competitive knowledge-based economy in the world as set out in the Lisbon Strategy, the use of technology and uptake of new technologies is becoming increasingly important
Keywords: technology, concerns, innovation, development
Non-Destructive Methods to Appreciate the State of Stesses and Cracks in Wheels and Railroads
The paper proposes three non-destructive experimental methods in order to establish some criterions for the maintenance inspections of the railroads. The first experimental method consists in drilling the railroad in different areas (head, basement and core of the rail profile). The bending capacity of the railroad is not adulterated after the drilling procedure. The residual surface stresses vanished around the hole, the deformations along 3 directions are measured with a rosette transducer and the values of the previous residual stresses will be calculated. The periodical ultrasonic inspection has been performed with a portable ultrasonic crack detector.
Keywords: tram, rail, maintenance, transducer, strain
Modelling and Optimization of Multiple Closed Loop Stands for Testing Gearboxes
In order to increase efficiency of testing gearboxes there is the choice of multiple closed loop test rigs. The paper presents the design, mathematical modelling and analysis of a two closed loop test stand, working in reversible regime. Energetic optimization of the system is based on minimization of energetic flow paths, loading and stress variation at reversible motion. Energetic equilibrium of loops imposes a symmetrical scheme and a central position of the drive motor. Different loading laws are needed for each rotation way in order to equalize contact stress of gears.
Keywords: test rig, gear transmission, multiple closed loops, energetic optimization, mathematical modelling, efficiency
The Ben Daniel-Duke Model Applied to Semiconductor Hetero-structure - Part 1
We investigate the semiconductor heterostructure with the Ben Daniel-Duke model applied for the lowest conduction states Ga As-Ga (1) as and for the heavy levels at in any heterostructures (1). In a quantic level we obtained the familiar staircase density of states(2). In (3) we calculated the incrgy position of the interface state in a single HgTe-CdTe heterojonction. We also obtained the existence of the interface state relies only on the relative position of the I'8 edges of HgTe and CdTe, their actual energy position, as well as their behavior at
Keywords: Ben Daniel-Duke model, heterostructure, quantum well, Ben Daniel-Duke quantum well
The Ben Daniel-Duke Model Applied to Semiconductor Hetero-structure - Part 2
We investigate the semiconductor heterostructure with the Ben Daniel-Duke model applied for the lowest conduction states Ga As-Ga (1) as and for the heavy levels at in any heterostructures (1). In a quantic level we obtained the familiar staircase density of states (2). In (3) we calculated the incrgy position of the interface state in a single HgTe-CdTe heterojonction. We also obtained the existence of the inter-face state relies only on the relative position of the I'8 edges of HgTe and CdTe, their actual energy position, as well as their behavior at .
Keywords: Ben Daniel-Duke model, heterostructure, quantum well, Ben Daniel-Duke quantum well
Work Accidents and Professional Diseases
The major accident is defined as "any event occurred, like an emission of dangerous materials or agents, which emerges from uncontrolled evolutions along the exploitation of any objective that leads to the immediate or delayed occurrence of serious dangers with impact over human health or over the environment, inside or outside the objective in which are involved one or more than one dangerous materials".The dangerous phenomenon is a potential source of harms. In the ambit of industrial risks of accidental origins, this expression more frequently refers to physical phenomena like conflagrations, explosions, toxic gases dispersion, etc.Any accident scenario relates itself to the potential effects at the level of environmental "targets". In the case of major accidents, we can distinguish the following categories of "targets": human (employees of the objective, working or resident people in the nearby of the emplacement); the installation or equipments that may stay at the origin of the accidents (dangerous equipments); certain all-important equipments to ensure the safety level of the installation (critical security equipments: control rooms, civil fire brigade headquarters, etc); goods and structures situated in the installation' environment (ground water, rivers, soil, flora, fauna).
Keywords: critical security, accidents, standards, system, work accident
Full Load Performance of a Spark Ignition Engine Fueled with Gasoline-Isobutanol Blends
With fossil fuels reserves coming ever closer to depletion and the issue of air pollution caused by automotive transport becoming more and more important, mankind has looked for various solutions in the field of internal combustion engines. One of these solutions is using biofuels, and while the internal combustion engine will most likely disappear along with the last fossil fuel source, studying biofuels and their impact on automotive power-trains is a necessity even if only on a the short term basis. While engines built to run on alcohol-gasoline blends offer good performance levels even at high concentrations of alcohol, unmodified engines fueled with blends of biofuels and fossil fuels can ex-hibit a drop in power. The object of this study is evaluating such phe-nomena when a spark ignition engine is operated at full load.
Keywords: spark ignition engine, biofules, isobutanol
Influence of the Tooth Helix Angle on the Vibrations of a Cylindrical Gearbox
The current trend in the construction of gearboxes, regarding the speed increase, favors the increase of the dynamic loads which are accompanying the operation of these kinds of machines. The phenomena of dynamic contact like frictions, collisions and shocks which are taking place in cinematic couples, engines and mechanisms during their movement, are generating vibrations in a wide range of frequencies.
Keywords: gearbox, vibration, gears, helix angle
The Use of Spark Ignition Engine in Domestic Cogeneration
Osman Kamil Sag
Cogeneration plants are strongly sustained by EU energy policies, one of the best beneficiary of this technology being residential buildings. This paper focus on spark ignition engine as a cogeneration application in order to supply energy for domestic consumers. Are considered two aspects of this solution: the energetic aspect and the environmental one. The energetic aspect deals with the energetic ratios, while the environmental aspect refers to the nitrogen oxide and carbon monoxide emissions.
Keywords: spark ignition engine, cogeneration, load
Aspects Regarding the Use of R-134a in Marine Refrigeration
In marine refrigeration and air conditioning, refrigerants like R-12, R-22 and R-502 are most commonly used.
Due to environmetal challenges, marine refrigeration plants on board of the old vessels have to be updated and designed in new terms. Recently, the global warming problem has put new pressure on possible alternatives, as R-134a for R-12, and drawn attention to energy efficiency.Results and theoretical considerations concerning a retrofit project are discussed with respect to R-134a compared with R-12, a traditional refrigerant on board of old ships.
Keywords: refrigerants, ozone, properties, ship
3D Modeling of Mechanical Transmissions for Base Translation of an Industrial Robot
Dumitru Adrian Stefan,
This paper presents 2 chained mechanical transmissions used to obtain the base translation of an industrial robot: worm - worm gear transmission and motion screw - nut transmission. The kinematical scheme, the 3D models of the main parts of the mechanical transmissions and the 3D assembly model are shown. For modeling, CATIA V5 software was used.
Keywords: modeling, mechanical transmission, industrial robot
Concept Model "Regional Center for Professional Development of Staff in the Education" Branicevo - Podunavlje Districts & Judetul Caras-Severin
"Knowledge management" in developing countries such as Serbia and Romania is based on information and education and represents our new social challenge and opportunity. Instead of natural resources and industrial capacity, knowledge management in education "becomes a vital resource of the information society, and innovation and generating "new knowledge "is the basis for wealth. Training the population and economy of these skills is a great opportunity for Serbia and Romania to join the developed countries and actively participate in global economic activity, but at the same time to maintain national and economic souvernity. Each educational organization should turn tacit, immaterial knowledge of their staff into substantive, explicit knowledge, which it then represents as the inalienable property. "Managing intellectual capital in the education" should focus on activities and the future of ICT, ie. strengthening the knowledge of its staff, because it is the constant development of the process, and it can be realized by forming regional centers for professional development in education.
Keywords: Regional center, knowledge, education, ICT, Branicevo - podunavlje District, Judetul Caras-Severin
Knowledge Management as Indispensable Factor in the Organizational Changes
"In the history of the modern world, there were three great waves of changes: agricultural, industrial and technological revolution. In the agricultural era, the acquisition of land was the key to success. In the industrial era, it was a capital and investment in capital goods. In the current technological era or the era of "knowledge", it has become a most valuable resource that one organization may have. To be creative and innovative, to think more further than others, have become critical characteristics for success. Technology has facilitated access to information, contributing to the further globalization of markets, automate industry and exponential growth of the amount of information. Knowledge has become the currency of our time, the key to survival and success. Transition from the culture-based industry represents a challenge for the way that people and companies think, work and function.
Keywords: knowledge management, change, intellectual capital
Transparency in Risk Management Does Mitigation and Decision-Making Process of Management
Tangible goods used for production, machinery, equipment and appliances, as well as natural forces and laws affected by them, which are allowing the creation of more favorable life conditions are often unpredictable and destroy what man creates and, eventually, cause property damage and aggravate the chances for progress of a mankind, production companies and society in general. Economic damage that thus occur, impelled the scientists to examine the frequency of such damage, in order to minimize or remove them completely.
Keywords: management, risk, process, identification, analysis, planning, control
Mathematical Model of Lifetime Duration at Insulation of Electrical Machines
This paper present a mathematical model of lifetime duration at hydro generator stator winding insulation when at hydro generator can be appear the damage regimes. The estimation to make by take of the programming and non-programming revisions, through the introduction and correlation of the new defined notions.
Keywords: model, estimation, lifetime, hydro generator, insulation
Pollutants Emissions from Marine Engines
In this moment for marine diesel engine, only NOx and SOx pollutants is limited by the international standards imposed by IMO (International Maritime Organisation), international authority for this activity domain. This paper describes the extension of the computer code make by author to simulate nitric oxide formation. Complex kinetic mechanisms are applicable only for simple flame computations (e.g. one dimensional, laminar, etc.). For real turbulent flame calculations, their use is impractical, due to the complexity of the interacting processes (turbulence, radiation, heat transfer, etc.). A model derived by systematic reduction of multi-step chemistry is used. This reduction is based on the partial equilibrium assumption of the considered elementary reactions using the extended Zeldovich mechanism.
Keywords: NOx, kinetic mechanism, partial equilibrium
Solutions to Mitigate Vibrations and Noise Produced by Tramways (State of Art)
Stroia Mihaela - Dorica
Vibrations and noises produced by daily human activities represent a major issue of nowadays, having a negative impact both on environment and on people. These negative effects occur with the human evolution and development and remain a problem that needs to be solved. The paper describes a part of the methods used on vibrations and noise damping, caused by road traffic, with reference in particular to tramways.
Keywords: vibration, noise, insulation, tramway
Simulation of the Operation Regimes of a Welding Transformer
The object of the paper is constituted by the simulation of the operation regimes of an electric transformer, using specialised simulation software, in order to determine the electromagnetic strains to which welding transformers are subjected to in the case of the faulty operation. The monitoring processes of the modern welding equipment impose the reduction of the risk of their breakdown, grace to the collection and processing of detailed information about the condition of the transformers with the help of specialised modelling software with finite element.
Keywords: transformer, welding, simulation
Simulation of Mechanical Transmissions for Base Translation of an Industrial Robot
Dumitru Adrian Stefan,
This paper presents the simulation of 2 chained mechanical transmissions used to obtain the base translation of an industrial robot: worm-worm gear transmission and motion screw-nut transmission. For simulation, CATIA V5 software was used.
Keywords: simulation, mechanical transmission, industrial robot
Computer-Aided Design of a Direct Current Electromagnet
The paper presents the mathematical model and the simulation of a direct current electromagnet used for the transport of the steel ingots. For the simulation of any device one must dispose of a mathematical model, able to describe as accurately as possible the phenomena that take place. As the processes occurred in the case of an electromagnet are of an electromagnetic nature, one used the model of the electro-magnetic potentials, and the simulation was performed with the help of the specialised software ANSYS.
Keywords: electromagnet, modelling, simulation
Optimization of the Withdrawal of Profiles at the Horizontal Continuous Casting Plant
In present, the withdrawal profiles at horizontal continuous casting plant is using a system which consists of a pair of parallel rollers electro-driven and executing a rotational movement with a sequential mechanism motor step-by-step reduction. The withdrawal roller has some major shortcomings: large size of the whole step by step motor-reduction requiring a pneumatic mechanism for raising the profile of the rolls, rolls are striated to pull the bar mold, which leads to visible traces on the profile shot. The proposed system uses instead of rollers (they have smaller surface contact) tanks that have adjustable horizontal surface contact plane. This profile provides a withdrawal force necessary to withdrawal without creating defects.
Keywords: role, tanks, proportional cylinders, control system, PLC
Management of Industrial Processes with Programmable Logic Controller
In a modern economy, automation (the control) is primarily to raise the competitiveness of a product, either directly through price or quality, or indirectly through the improvement of working conditions of staff productive. The control of industrial processes involves the management of dynamic systems that have continuous states. These systems are described by differential equations and, in general, analog inputs and outputs. Management of these systems is achieved, in general, with classical automation, by automation or with analog computers which contains modules with input/output analog performance. If states, inputs and outputs of a system can be modeled using binary variables, then these systems can be driven with Programmable Logic Controller.
Keywords: management, industrial processes, programmable logic controller