Anul XVII (2010), Nr. 1
TABLE OF CONTENTS
Direct Search Based Strategy for Obstacle Avoidance of a Redundant Manipulator
This paper presents an iterative direct search based strategy for redundancy resolution.
The end-effector of the redundant manipulator achieves the imposed task of following the contour of a curve,
while fulfilling two other performance criteria: obstacle avoidance and minimization of the sum of joint
displacements. The objective function to minimize is the sum of joint displacements, while the obstacle
avoidance and end-effector task are expressed as non-linear constraints. The proposed direct search based
strategy is iterative; the joint configura-tion computed in the previous step represents the current point
around which the generalized pattern search algorithm is successfully performed.
Keywords: redundant manipulator, direct search strategy, obstacle avoidance
Aspects Regarding Data Processing Obtained from Measurements for Braking System
Verification of Winding Installation Machines
Wilhelm W. Kecs,
The paper presents aspects on data processing obtained following measurements and recordings made in view
of verification of braking system of winding installation machines. To exemplify these aspects, braking
system verification of winding installation machine at Shaft 2 in Lupeni Mining Plant and the braking
system of winding installation machine of Central Shaft at Petrila Mining Plant were studied.
Keywords: data processing, winding installation machines
Considerations Concerning the Dynamics of Vibratory Mills Used in Powders’ Mechanical Milling
Dynamic mechanical milling process in a powder mill was studied by analyzing the vibratory effects of
vibration and shock phenomena on the material microstructure ground. During the milling process, there were
noticed both distinct modes of ball motion: the one generated by the periodic vibration and the one
produced by chaotic vibration.
Keywords: ivibration phenomena, collision, impact force
Analysis of a Mechanical System’s Dynamic Properties by Vibrations Measurements
This paper aims to present some theoretical notions about the solution of the reverse problem in the
dynamic response study of a mechanical system. Thus, by measuring vibration, some dynamic properties of the
mechanical system considered can be determined.
Keywords: mass, stiffness, damping, measuring vibration
On the Nanoindentation of the Carbon Nanotubes
Petre P. Teodorescu,
A new inverse approach is proposed in this paper, which combines elements of nonlocal theory and
molecular mechanics, based on the experimental results available in the nanoindentation literature. The
effect of the inlayer van der Waals atomistic interactions for carbon nanotubes with multiple walls (MWCNT)
is included by means of the Brenner-Tersoff potential and experimental results. The neighboring walls of
MWCNT are coupled through van der Waals interactions, and the shell buckling would initiate in the outermost
shell, when nanotubes are short. The nanoindentation technique is simulated for the axially compressed of
individual nanotubes, in order to evaluate the load-unloaded-displacement, the curve critical buckling and
the appropriate values for local Lamé constants.
Keywords: nanoindentation, carbon nanotubes, buckling, Brenner-Tersoff potential,
van der Waals force, kink
The Simulation of the Functioning of a Hybrid Vehicle
In the paper we present a functional model and its mathematic modeling of the movement of the mechanism
that simulates the functioning of a hybrid vehicle. The mechanism used for the coupling of three electric
engines of continuous current with permanent magnet stator is a planetary mechanism with a double satellite.
The functional model operation is ensured by an electronic module which allows the supply voltage variation
of electric motors and an electronic device. In order to study the movement of the mechanism from a
mathematical point of view we have designed a mathematic model with two degrees of freedom. We obtain the
solution in transition phase and in permanent phase after obtaining the differential equations of motion
using Lagrange's equations.
Keywords: hybrid, functional mechanism, power sources, planetary mechanisms, differential
Optimisation Methods for Cam Mechanisms
Claudia – Mari Popa,
In this paper we present the criteria which represent the base of optimizing the cam mechanisms and also
we perform the calculations for several types of mechanisms. We study the influence of the constructive
parameters in case of the simple machines with rotation cam and follower (flat or curve) of translation on
the curvature radius and that of the transmission angle. As it follows, we present the optimization
calculations of the cam and flat rotation follower mechanisms, as well as the calculations for optimizing
the cam mechanisms by circular groove followers’ help. For an easier interpretation of the results, we
have visualized the obtained cam in AutoCAD according to the script files generated by a calculation
Keywords: CAM, curvature radius, constructive parameters, pressure angle, circular grove
On the Efficiency of a Base Isolation System
IThe aim of this paper is to present the analyses of the efficiency for a base isolation system. To
portray the hysteretic behavior of the devices used for seismic protection the Bouc-Wen model is used. The
non-linear first order equation which can describe the evolution of force de-veloped by one device for
almost any loading pattern are added to the system of equations which models the dynamical behavior of the
pro-tected building. Using Matlab-Simulink software, the model are employed to investigate the efficiency of
the base isolation devices by comparing the seismic response of protected and unprotected buildings
subjected to strong seismic actions.
Keywords: hysteretic characteristics, base isolation system, Bouc-Wen model
Rigidity Influence of Suspended Cable on Free Vibration Modes
Emil Matei Videa
The problem of vibration control of overhead line conductors subjected to laminar transverse wind,
inducing stationary vibrations by Karmán effect is of high importance due to consequences upon these
structures lifetime and service. We consider the cable model as Euler-Bernoulli beam that include the
influence of cable rigidity and that respect the author condition which detaches the suspended cable
model of the beam model with viscous, hysteretic or dry friction internal damping hypothesis. The
original analytical expression of the free vibration modes and the resonance frequencies equation for
the cable with clamped extremities has produced. Some experimental aspects are underlined in the paper.
Keywords: Euler-Bernoulli beam, suspended cable model, vibration mode, damping, analytical
A Study of Annular Plate Buckling Problem with Tension Loaded at Inner Edge
Waleed Fekry Faris
The buckling problem of annular plate with only one edge (either inner or outer edge) constrained is
formulated and presented in this paper. The boundary condition is simply supported inner edge-free outer
edge. The results are compared between the FEM results obtained using ABAQUS and results reported in
literature. The results shows good agreement for critical buckling load, mode shapes and stress
Keywords: piezoelectric, annular, buckling, methods of multiple scales
The Ultrasound Propagation Analysis through Two Mediums in Case of High Energy Piezoelectric Transducer
Grigore Liviu Odobescu
The high energy ultrasound it is generated by piezoelectric elements which are excited from electric
signal obtained from an electronic generator. The transmission of this high energy it is obtained by
transmission element or concentrator element in function of what we want to do with this energy especial
utilized in no conventional technology. The efficiency work is very important aspect because the energy
utilizes has high values. In this paper it is presented methods to calculate the elements components
necessary to generates and transmits the high ultrasound energy: piezoelectric transducers and
transmission / concentrator elements. It is presented the experimental results obtained with the theory
presented. Original contribution consists by method used and suggestive graphics for appreciation of
Keywords: ultrasound, vibration, propagation, piezoelectric transducer
The Analyzing of Ultrasound Propagation Wawes through a Piezoelectric Transducer in Function of
Grigore Liviu Odobescu
The nature of acoustic charge, which works with an electronic generator to generate high intensity
ultra-acoustic field is very various in function of application used . The values of elements from
equivalent scheme may be to vary in time in function of technologic process . This fact determines
the variation of accord frequencies and value of acoustic charge. In this manner the efficiency can be
modified in time if it no take measures to minimize these influences of complex impedance that works
with electronic generator . In this paper it is presented a method to analysis the influence of
variation of acoustic charge and to minimize this influences for to assure an optimum operation of
electronic generator, it is presented a program to calculate the power variation in function of acoustic
charge and to chart the diagram of this variation. It is presented the experimental results obtained with
the theory presented.
Keywords: acoustic charge, ultrasound vibration, piezoelectric transducer
Behavior at High Temperatures of Steel Used for Constructions (Reactions to Fire)
The purpose of the present paper is to determine the response of main elements and resistance structures to
extreme circumstances, specifically to action of conflagration, considering the temperature distribution
inside structure’s elements, materials characteristics – steel for this case – following
the determination of thermo-mechanic response of main elements and resistance structures.
Keywords: structure, resistance, temperature, steel
Two Degrees of Freedom Non-linear Model to Study the Automobile’s Vibrations
In this paper we present a non-linear model for the study of an automobile's vibrations.
The model has two degrees of freedom and it is highly non-linear.
The forces in the springs are considered to be given by a polynomial potential.
The equations of motion are obtained using the Lagrange second order equations.
We determined the equilibrium positions. We proved the conditions for the uniqueness of the equilibrium.
In our paper we studied the stability of the equilibrium and the stability of the motion.
Finally a numerical application is presented.
Keywords: non-linear, vibrations, stability, automobile
The Equilibrium of the Solid Rigid with Constraints
In our paper we obtain the matrical equations of equilibrium for a solid rigid with constraints.
These equations are deduced from the Lagrange equations. Finally we present a completely solved example.
Keywords: Lagrange equations, pseudo-coordinates
A Kinematic Analysis of the Variable Valve Timing Mechanism with Three Elements and Continuous
An innovating solution for throttle-free load control for spark-ignition engines is Variable Valve Timing
system (VVT System, or VVA - Variable Valve Actuation System). In this paper is presented an analytic method
for kinematic analysis of the valve timing mechanism with three elements, which mainly includes the camshaft,
the roller rocker finger and an intermediate rocker arm. This type of mechanism ensures a continuous valve
lift (VVL System) between two extreme valve heights. It is also presented the numerical example for the
variable valve lift mechanism’s motion.
Keywords: Variable Valve Lift, Mechanism, Kinematic analysis
The Predicting of the Size Effects in the Buckling of the Carbon Nanotubes
Pier Paolo Delsanto,
It is well-known that the nanoindentation hardness displays strong indentation size effects. In this paper,
the size dependence of the hardness with respect to the depth and the indenter radius for the buckling of
multiwalled carbon nanotubes is investigated using the Toupin-Mindlin strain gradient theory. As expected,
the indentation hardness is closely related to the depth and the indenter radius. Qualitatively, the
responses of the axially compressed multiple walled carbon nanotube agree remarkable well with the
Keywords: Nanoindentation, carbon nanotubes, buckling, size effects, Toupin-Mindlin theory
Dissipation Effect in the Hunting Motion Stability of Wheel Set with Elastic Joints
Nistor Simona, ,
The axle hunting is a coupled lateral and yaw self oscillatory motion which is largely determined by
wheel–rail contact geometry. The stability of this motion is an important dynamic problem that
determines the maximum operating speed of railway vehicle. To improve the stability performances, without
increasing the rail-wheel interaction forces above safety limits, elastic joints and dissipative devices
are used to connect the wheelset to the bogy frame. In this paper is studied the influence of passive linear
and non-linear dissipative horizontal forces on the hunting motion stability of a wheelset with elastic
Keywords: Hunting motion, nonlinear dissipation, critical speed
The Computation of the Efforts into the Plan System of the Elastic Bars which Suspends a Rigid with
One considers that the rigid with constraints acted by the external forces suported by the elatic bars
embedded at the base. Under the influence of the external forces appear the connection forces and the
displacements in the kinematic pairs. One deduces the mathematical model for the computation of the
reactions and the displacements and one makes a numerical applications.
Keywords: rigid, constraints, elastic, joint bars
Rehabilitation of Plant Units at Pumping Stations
Tiberiu Ştefan Mănescu,
Mihaela Dorica Stroia,
Silviu Dan Avram, ,
Loretta Simona Chivu
During operation process, industrial pumps are subjected to wear and corrosion that often lead to various
physical damages and functional faults. Although this is not a habitual case, when occurs, it is very
expensive to replace the affected parts with new ones and in most of situations this isn’t the best
problem solving. A way to deal with this type of problem at pumping stations is rehabilitation of plant
units. The present paper describes a solution to rehabilitate worn pumps using CERAMITECH treatments based
on epoxy resin and polyamine-amides reinforced with carbide and ceramic particles. Also it shows
measure-ments before and after using the treatment.
Keywords: pump, treatment, characteristic curve, CERAMITECH
Studies Regarding Design and Optimization of Mechanisms Using Modern Techniques of CAD and CAE
Adelin Ionel Tuţă
The paper presents applications of modern techniques of CAD (Computer Aided Design) and CAE (Computer Aided
Engineering) to design and optimize the mechanisms used in mechanical engineering. The use exemplification of
these techniques was achieved by designing and optimizing parts of a drawing installation for horizontal
continuous casting of metals. By applying these design methods and using finite element method at
simulations on designed mechanisms results a number of advantages over traditional methods of drawing and
design: speed in drawing, design and optimization of parts and mechanisms, kinematic analysis option,
kinetostatic and dynamic through simulation, without requiring physical realization of the part or mechanism,
the determination by finite element method of tension, elongations, travel and safety factor and the
possibility of optimization for these sizes to ensure the mechanical strength of each piece separately.
Achieving these studies was possible using SolidWorks 2009 software suite.
Keywords: CAD, CAE, optimization, simulation, continuous casting
Simulation of Oscillatory Working Tool
The paper presents a study of the resistance forces in soils cutting, with emphasis on their dependence
on working tool motion during the loading process and dynamic regimes. The periodic process of cutting of
soil by a tool (blade) has described. Different intervals in the cycle of steady-state motion of the tool,
and several interaction regimes were considered. The analysis has based on a non-linear approximation of the
dependence of the soil resistance force on tool motion. Finally, the influence of frequency on the laws
governing the interaction in the cyclic process was established.
Keywords: cutting, soil, blade, vibrations, dynamics
Considerations upon the Characteristic Frequency Spectra of some Road Transportation Means
The noise generated by the road transportation means is characterized by frequency spectra,
acoustic pressure levels and their variations in time. The sources of vibration and noise depend on the
transportation mean type. Therefore every transportation mean identifies itself by characteristic frequency
spectrum and noise level. Using the recording of the frequency spectra of the transportation means, one can
identify the attenuation methods of the generated noise. In this paper we pre-sent some results obtained
in the study of the noise generated by the road transportation means using the frequency spectra.
Keywords: road transportation means, noise, frequency spectra
Theoretical and Numerical Analysis for the Design of a Safety Barrier as Road Restraint System
Constantin Vasile Bîtea,
The paper deals with a theoretical background and with numerical studies achieved on an N2 safety barrier,
with normal protection. In order to determine the impact force, a model at a reduced scale was proposed.
For the calculus of the dynamic load due to the impact, the corresponding maximum deflection was determined.
In the same time, the equivalent stress distribution was plotted for the examined case.
Keywords: safety barrier, numerical analysis, car crash
Comparative Analysis of Visco-elastic Models with Variable Parameters
The paper presents a theoretical comparative study for computational behaviour analysis of vibration
isolation elements based on viscous and elastic models with variable parameters. The changing of elastic
and viscous parameters can be produced by natural timed evolution demo-tion or by heating developed into
the elements during their working cycle. It was supposed both linear and non-linear numerical viscous and
elastic models, and their combinations. The results show the impor-tance of numerical model tuning with the
real behaviour, as such the characteristics linearity, and the essential parameters for damping and rigidity.
Multiple comparisons between linear and non-linear simulation cases dignify the basis of numerical model
optimization regarding mathematical complexity vs. results reliability.
Keywords:Visco-elastic model, variable parameters, spectral characteristic
Transmission Loss Assessment for a Muffler by Boundary Element Method Approach
This paper investigates the acoustic performance of two cases for reactive mufflers using Boundary
Element Method (BEM) analysis. Modeling procedures for accurate performance prediction had led to the
development of new methods for practical muffler components in design. The transmission loss (TL) is the
more widely can be easily computed with a BEM analysis. The author presents an overview of the principles
and theoretical formulation of BEM for predicting the transmission loss of a muffler, the pressure and
velocity distribution on surfaces of muffler. At the end of the paper is presented a comparison of two
cases of mufflers for transmission loss. The predicted results agreed in some limits with the experimental
data published in literature.
Keywords:muffler, transmission loss, BEM
Methods of Simulation for Dynamic Systems with Friction
Mihai Ilie Toader
In this paper the contact/impact between two bodies is accentuated by simulations using the ANSYS code.
In the present study has been selected the ANSYS/LS-DYNA code because it is used in the simulation of
contact/impact. This computer code performs nonlinear transient dynamic analysis of three-dimensional
Keywords:friction, contact, impact, mathematical model
Intelligent Agent for Damages Detection
Esperanza Maria Suarez-Sanchez
We introduce in this paper an intelligent system that automatically de-tects the damage in cantilever
beams called AgentMec. This agent is creating its knowledge using a database with the first ten natural
frequencies of the beam damaged at pre-determined points. Using the reinforced learning, it creates the
patterns to describe the behavior of the damaged beam. Then with each new vibration measurement send as
input, AgentMec is able to recognize the location of the damage.
Keywords: intelligent agent, damage, identification, vibration, frequency
Evaluation of Elastic Forces Resulted from the Impact Vehicles - Flexible Barriers
The paper approaches initiation and finalizing of the percussion process for the system
vehicle-flexible barrier basing on analytical evaluations and principle of equivalence for
the mechanical resistance in case of experimental results transfer between two different
Keywords: flexible barrier, impact, elastic deflection, equivalent actions
Anul XVII (2010), Nr. 2
TABLE OF CONTENTS
Model Equations of Shape Memory Effect - Nitinol
Călin Octavian Micloșină
Even it has been already confirmed that SMA’s have high potential for robotic actuators,
actuators included in space robotics, underwater robotics, robotics for logistics, safety, as well as
“green robotics” (robotics for the environment, energy conservation, sustainable development or
agriculture), the number of applications of SMA-based actuators is still quite small, especially in
applications in which their large strains, high specific work output and structural integration potential
are useful,. The paper presents a formulated mathematical model calculated for binary SMA (Ni-Ti), helpful
to estimate the stress distribution along with the transformation ratio of a SMA active ele-ment.
Keywords: shape memory, modeling, actuation, thermo mechanical transfer, Nitinol
The Way of Establishing a Relative Position for Some Production Units
Olga Ioana Amariei,
Constantin Dan Dumitrescu
The CRAFT Method was at the basis of the development of the heuristic commuting models, in which one
starts from an initial emplacement of units that is successively improved, through the successive commuting
of units among them on the basis of some criteria. In the present paper we have resolved to the Facility
Location and Layout module of the WinQSB program that uses the CRAFT Method in solving problems of the
Functional Layout type.
Keywords: initial emplacement, efficiency, relative position, rectilinear model
Lean Manufacturing - A Powerfull Tool for Reducing Waste During the Processes
Ionela Roxana Arvinte
Lean manufacturing provides a new management approach for many small and medium size manufacturers,
especially older firms organized and managed under traditional push systems. Improvement results can be
dramatic in terms of quality, cycle times, and customer responsiveness. Lean manufacturing is more than a
set of tools and techniques and has been widely adopted by many production companies. Lean manufacturing is
a culture in which all employees continuously look for ways to improve processes. In the present article are
presented the Lean Manufacturing tools, like kaizen, Kanban, poka-yoke witch a company can use to reduce the
waste(muda) during a production process. The paper contains also, the most common seven types of waste from
production and some examples from our daily activity.
Keywords: lean manufacturing, waste, lean tools, Kanban, leaner company
Clusters Regarding Key Factors Affecting Changes in Accounting, Finance, Administration and Management
Rodica Gabriela Blidisel,
Adina Simona Popa,
Raimondo Lo Russo,
During the last decade, important changes have occurred in public governance, which has evolved in this
time from hierarchical bureaucracy to participatory governance, where the role of citizens in public
decision-making process is more direct. There were performed reforms in finance, management administration
and finances of public sector. Starting from the factors that influenced during the history the accounting,
finances, administration and management control, we want to test the factors that affect the changes of
these elements in Romanian environment.
Keywords: cluster analysis, dendogram, accounting
Magneto Rheological Semi-Active Damper with External By-pass Circuit in Modular Structure
In order to perform experimentally studies, in the paper it is presented a simple method which was
elaborated to realize reliable, at low cost and reproducible semi-active dampers with magnetorheological
fluids, having external magnetic circuit. The main components are common constitutive elements of industrial
hydraulic and pneumatic drivers, having the supplementary advantages being manufactured in a large scale of
overall dimensions and demanding minimal modifications. As accumulator, a similar type of hydraulic or
pneumatic cylinder was used. The work of the whole damper can be optimized by modifying the nitrogen
pressure and interior volume of accumulator. Another important advantage of this conception is the
possibility to realize a modular structure composed by the damper, accumulator and magnetic field generator,
interconnected by flexible elements.
Keywords: magnetorheological fluid, semi-active, by-pass circuit, modular structure
Analytical Method to Estimate Fatigue Life Time Duration in Service for Runner Blade Mechanism of
Ana – Maria Budai ,
The paper present an analytical method that can be used to determianted fatigue life time duration in
service for runner blade mechanism of Kaplan turbines. The study was made for lever button of runer blade
mechanism using two analytical relation to calculate the maximum number of stress cycles whereupon the
mechanism work without any damage. To estimate fatigue life time duration will be used a formula obtained
from one of most comon cumulative damage methodology taking in consideration the real exploatation
conditions of a specified Kapaln turbine.
Keywords: fatigue, runner, blade, mechanism
Influence of Working Environment on Fatigue Life Time Duration for Runner Blades of Kaplan Turbines
Ana – Maria Budai,
The paper present an analytical analyzes refer to influence of working environment on life time duration
in service of runner blades of Kaplan turbines. The study are made using only analytical method, the entry
dates being obtained from measurements made in situ for a Kaplan turbine. To calculate the maximum number of
stress cycles whereupon the runner blades work without any damage it was used an analytical relation known
in specialized literatures under the name of Morrow’s relation. To estimate fatigue life time duration
will be used a formula obtained from one of most common cumulative damage methodology taking in
consideration the real exploitation conditions of a specified Kaplan turbine.
Keywords: fatigue, runner, blade, environment
Heat Treatments and Materials Used in the Manufacturing of the Gear Wheels
Virgil Dan Cărămidaru,
For the reducers used for a certain application, a relative reduced number of materials joins the
discussion, respectively procedures of heat treatment, the decision was taken conditioning aspects, as:
functions solicitated to the transmission (movement transmission, durability, behaviour to the noise),
number of the pieces and the manufacturing procedure.
Keywords: steels and cast irons, hardenability, depth of quench hardening, superficial
hardness and wear resistance
Solar Photovoltaic Plant for the “Eftimie Murgu” University of Resita
Cristian P. Chioncel,
The paper presents an application of a solar photovoltaic plant for the “Eftimie Murgu”
University, with an estimation of the yearly medium energy production. The substantiation of the plant
design is based on the many years measurements obtained in the laboratory for monitoring the solar
photovoltaic energy of the university and the favorable conditions of promoting the energy production
from renewable sources, assured in the new legislation.
Keywords: solar photovoltaic conversion, solar module, inverter, motor - generator group
Complex Technical Solution for Renewable Energy
Cristian P. Chioncel,
This paper presents a complex technical solution for implementing renewable energy, namely: wind,
solar photovoltaic and hydraulics. Because wind and solar photovoltaic energy have a highly random
character, it is required to find solution to store the product energy for unfavorable periods, without
wind or solar radiation. This could be achieved using the third type of renewable energy, the hydraulic one,
obtained form an hydroelectric pumped storage plant (HPSP), located in the im-mediate vicinity of the wind
and solar photovoltaic plant.
Keywords: renewable energy, wind, solar photovoltaic, hydraulic
Noise Map - a Necessity
Tiberiu Ştefan Mănescu
In contrast to many other environmental problems, noise pollution continues to increase thanks to
industrial, social and transportation field development. The paper analyze specific aspects on the
impacts of noise on health, to identify areas for priority action and remediation measures.
Keywords: urban road, traffic, noise, level, map
The Influence of Some Factors on Maximum Depth in Electrohydraulic Forming
The paper presents the results of the author`s experimental research concerning the influence of
discharge voltage of condensers battery, condensers battery capacity, discharge axis - plate distance
and electrode gap on the shock wave maximal pressure and, implicit, on maximum drawing depth which can be
realized to the plate, in the case of electrohydroimpulses drawing in the high voltage domain, between
20...50 kV, in a cylindrical universal discharge chamber. Are presented some considerations regarding the
influence of gas bubble pressure.
Keywords: drawing depth, electrohydraulic forming, voltage, distance
A Method to Study Thickness Reduction in Electro-hydraulic Forming of Cones
In this paper are presented some of the authors experimental researches connected to the
electrohydroimpulses drawing of the thin conical parts made from aluminium, and also to the quality
of these parts. Experimental conditions are specified and comparatively presented some results obtained
for the same kind of parts, but in the case of magnetic impulses drawing (magneto – dynamic
deformation). As a criterion for the quality of the parts obtained by electrohydroimpulses drawing
in monoimpulse regime, the distribution of material’s thickness reduction lengthways with the cone
element is adopted, for different geometries of the cone. The study is achieved for various intermediate
deformation stages and discharge energies.
Keywords: cone, electrohydraulic forming, thickness, quality, drawing
Check Interior Surfaces of the Oil Conservatories of the Power Transformers
Paper presents two experiments designed to verify traversing the inner surfaces of the oil conservatories
of the power transformers. Corrosion of internal surfaces of the oil conservatories is a negative aspect,
which may affect safe operation of power transformers. Rust particles thus formed, migrate vat transformer
insulating oil quality worsening. To prevent such situations should be regular monitoring of the interior
surfaces of the oil conservatories.
Keywords: oil conservatories, rust, insulating oil, the safe operation
Analysis of the Transitional Process into Naval Electrical Equipment
The analysis is based on a naval power with synchronous generator and consumers of various powers.
The paper presents a systemic approach to naval power systems based on mathematical models of specific
generators and consumers.
Keywords: transitional arrangements, electric power system, synchronous generator,
mathematical models, the shock load
Ship Traffic Modeling and Performance Evaluation in Container Port
Nenad Dj. Zrnić,
This paper gives ship traffic modeling and performance evaluation in container port. The basic approach
used analytical and simulation models. These models are developed for impact analysis of the ship traffic
and patterns of arrival ships at terminal performance. Results from both models are compared with each other.
Both the simulation and analytical models were applied to evaluate the efficiency of PECT.
Keywords: ship traffic modeling, analytical and simulation models
Calculation Method for the Displacements of Cross Sections for Unsupported Straight
Bars Subjected to Axial or Torsion Loads
This paper discusses a method for the determination of the displacements of the cross sections for
unsupported straight bars subjected to axial loads – with forces or moments. The displacements of
the cross sections are determined against their initial position, as well as against the section or sections
that do not displace during static loading. The section or sections that do not displace against itself or
themselves during the tensile-compression load or during the static torsion load are also determined with
the help of this method.
Keywords: displacement, deformation, unsupported bars, cross sections
Study of Volumetric Efficiency for Spark Ignition Engines Using Alternative Fuels
One of the most important parameter for spark ignition engines is volumetric efficiency, as it directly
influences specific power output. Several definitions of this parameter are studied from a theoretical
point of view, taking into consideration the use of alternative fuels. The influence of using
gasoline-bioethanol blends is investigated, as well as the effect of fuelling spark ignition engines with
methane, liquefied petroleum gas and hydrogen. Bioethanol features the highest volumetric efficiency, while
gaseous fuels cause a drop in specific power output compared to gasoline operation.
Keywords: spark ignition engines, volumetric efficiency, alternative fuels
Computer Aided Design of Kaplan Turbine Piston with SolidWorks
The paper presents the steps for 3D computer aided design (CAD) of Kaplan turbine piston made in
SolidWorks.The present paper is a tutorial for a Kaplan turbine piston 3D geometry, which is dedicaded to
the Parts Sketch and Parts Features design and Drawing Geometry and Drawing Annotation.
Keywords: Kaplan turbine piston, SolidWorks, 3D geometry
Computer Aided Design of the Link-Fork Head-Piston Assembly of the Kaplan Turbine with Solidworks
Constantin Viorel Câmpian
The paper presents the steps for 3D computer aided design (CAD) of the link-fork head-piston assembly of
the Kaplan turbine made in SolidWorks.The present paper is a tutorial for a Kaplan turbine assembly 3D
geometry, which is dedicated to the Assembly design and Drawing Geometry and Drawing Annotation.
Keywords: Kaplan turbine assembly, SolidWorks, 3D geometry
Dynamic Modelling of a Single Stage Cylindrical Gearbox
Gearboxes are frequently used in machine systems for power transmission, speed variation and/or working
direction. Dynamic modelling of gear vibration offers a better understanding of the vibration generation
mechanisms as well as the dynamic behaviour of the gear transmission in the presence of gear tooth damage.
Keywords: gearbox, vibration, gears, modelling, simulation
The Tendencies of Piece Casting from Modified Irons
Cinca Ionel Lupinca,
Ileana Veronica Rigou,
Cornelia Ecaterina Cornean
In this paper we have presented the metalographic studies made on the grey cast irons treated with
complex modifying substances, type FeSiMgRE (Mg alloy) and their influence on the compactness degree of
graphite separations. For research and experiments, a melt of grey iron was produced in an induction furnace
of a capacity of 5to, starting with a metallic charge made from 100% synthetic pig iron. We realized eight
practical charge made modification, by using different combinations of modifying substance and in different
concentrations. The addition of carbon to the melt was performed using electrode graphite powder in the
Keywords: synthetic pig iron, compactness degree graphite
Studies Regarding the Elaboration of the Manganese Austenitic Steel in the Induction Electric Furnace
with Acid Coating
The paper forwards a method of elaborating the manganese austenitic steel in induction electric
furnaces with a capacity of 250 Kg having an acid furnace coating. Considering the fact that when
elaborating the manganese austenitic steel sulphur can be obtained under 0.02% constitutes an additional
reason to attempt the elaboration of this steel in the electric furnaces through induction with acid
coating, even if the load has over 0.02% S.
Keywords: steel, austenitic, induction furnace, acid coating, elaboration, Hadfield steel
Application of Mathematica Software for Estimate the Fatigue Life Time Duration of Mechanical System
Petru Florin Minda,
The paper present how we can use Mathematica to solve the equations types usually used to determinate
the maximum stress cycles that can be support by a mechanical system until he will be out of use. To
illustrate the type of equations used in specialized literature to estimate fatigue life time duration was
chosen a specific case of mechanical structure applied to fatigue. It is about lever button of runner blade
mechanism of Kaplan turbine, that in function support a very intensive alternative strain.
Keywords: fatigue, equation, algorithm, mechanism
Methods of Reducing Emissions from Two-stroke low-speed Diesel Engines
The worldwide focus on fuels is generally increasing because of the focus on exhaust gas emissions.
General awareness of environmental issues is increasing rapidly. Diesel engine makers were first involved
in questions regarding exhaust gas emissions in the field of stationary applications. A study of the exhaust
gas emissions from a diesel engine represents a challenge to both the engine designer and to makers of
exhaust gas treatment equipment. It is also a valuable tool for reaching a deeper understanding of the
engine combustion process. These emissions control technologies, like Selective Catalytic Reduction (SCR),
will help to reduce pollutants that impact our health and the health of our communities as well as reduce
smog creation and other factors that contribute to climate change and global warming.
Keywords: emissions, SCR, IMO proposal
Mathematical Model for the Contact Stress Calculation of Fluoropolymerized Toothed Wheels
In this paper is presented a contact stress calculation algorithm for a new type of cylindrical toothed
wheel. This new type consists in the application of a Xylan 1052 fluoropolymer film on the surface of a
metal toothed wheel. Due to the fact that the steel strength, in any case is better than the plastic
strength, the main issue which appears is at the contact between the two homologous flank surfaces.
Keywords: toothed wheel, fluoropolymer, stress contact calculation
Analysis of Main Types of Vibrations at a Bridge for Passer-Byes
The present paper deals with the dynamic mode analysis in different situations at a bridge projected
for passer-byes, with the help of the AxisVM software. From the multiple studied modes of vibrations we are
going to present the main vibrations which appear due to the self-weight of the bridge, due to complex
forces (different loads), and also due to seismic forces (mode 1 and mode 9).
Keywords: modal analysis, complex forces, seismic forces
Numerical Behavior Reproduction of a Truss Structure and Beam, Subjected to Concentrated Load
The paper deals with a numerical reproduction of a real experiment consisting of the same restraints
and concentrated load applied to a truss structure and beam; the numerical reproduction was performed with
SolidWorks software, where both geometrical reconstruction and finite element analysis were made. The goals
of the analysis was to compare the numerical with experimental results and to evaluate the best structure
using the structural response criteria.
Keywords: finite element, truss, beam, SolidWorks
Optimal System for the Compensation of the Reactive Power with Synchronous Motors
Adrian Valentin Petrica
In the activity of some factories that use synchronous motors it’s nec-essary to chose and maintain
the most rational value of the reactive power provided by the synchronous motors. In the context of the
reduction of the energy consumption and knowing that the power of the synchronous motors is relatively great
in the air compressor stations, the approach of the optimal regime of functioning of the synchronous motors,
concerning the energy consumption, is necessary. Considering the synchronous motors together with the other
consumers fed from the same bars and the feeder cable a functional utility, in the paper as optimising is
presented the working regime that assures, on the defined above assembly, the minimal losses of energy.
Keywords: synchronous motors, energy consumption, air compressor stations
The Compensation of the Reactive Power with Synchronous Motor
Adrian Valentin Petrica
An optimal control system for the compensation of the reactive power in an energetic consumer assembly
is presented, containing one or more synchronous motors, connected to the same power bars in parallel,
including synchronous motors and static converters. The compensa-tion of the reactive power absorbed from
the system by the consumers is possible, using a optimal control system that controls the reactive power
provided on the bars by the synchronous motors on condition that the power losses in the created whole are
zero. A limited functional block diagram of the synchronous motor, which is the controlled object completed
with the control circuits of the exciting tension and current is obtained having as set value the sum of all
reactive currents of the consumers from the power assembly. The optimization is obtained using the module
criterion of Kessler.
Keywords: synchronous motor, reactive power, block diagram
Air Compressor Driving with Synchronous Motors at Optimal Parameters
Adrian Valentin Petrica
In this paper a method of optimal compensation of the reactive load by the synchronous motors, driving
the air compressors, used in mining enterprises is presented, taking into account that in this case, the
great majority of the equipment (compressors, pumps) are generally working a constant load.
Keywords: air compressor, synchronous motor, reactive load
Model for the Study of Automating a System of Pumping Water from Upstream to Downstream Hydropower Plant Using
Siemens S7-200 PLC
This paper shows the realization of an experimental model for studying didactic use automation system
pumping water from upstream to downstream hydropower. As command and control unit was used PLC Siemens
Keywords: model, pumping, automation, PLC
Laboratory Facilities for Testing Thermal Engines
This work presents an electromechanical plant through with which is realised couples different resistant,
MR (0 ÷ MRN), on the gearbox shaft of internal combustion engine. The purpose is to study the plant in
phase and stationary behaviour of the main technical parameters that define the engine operation such as:
torque, speed, temperature, pressure, vibration, burnt gas, noise, forces. You can take measurements to
determine engine performance testing and research on improving engine thermal efficiency. With the proposed
plant is built by measuring the characteristic internal combustion engines (tuning characteristic and
functional characteristic) and determine the technical performance of interest, optimal.
Keywords: engine, testing, diagram acquisition, modeling
Stationary Magnetic Field of an Electric Circuit Laid out on the Floatation of a Ship
This paper presents the calculus algorithm of the intensity of the magnetic field for a maritime ship.
The following have been analyzed: the magnetic field created by a live oriented right line segment and the
magnetic field created by oriented circuit segments positioned across in the floating plane from a ship side
to the other. The spreading of the magnetic field has been calculated for a ship with a view to compensate
the vertical component of the terrestrial magnetic field.
Keywords: stationary electromagnetic field, electric circuit, ship demagnetization,
The Stand for Determination of Service Performance in Load of a Welding Transformer Using the LabVIEW
This paper presents the way of performance’s characteristics determi-nation in load of welding
transformers` performance parameters using the data acquisition systems through virtual tools.
Nowadays observing the parameters of welding service and of welding instruments` charac-teristics means
an important step regarding the quality of weld throat.
Keywords: transformer, start under load, welding, data acquisition
Analytical Identification, Simulation and Analysis of Steel Solidification Process in Crystallizer
Gelu Ovidiu Tirian,
To do an analysis of the phenomena that lead to cracks in continuous casting process is necessary to
study the heat exchange and steel solidification. Thus, this paper proposes a modeling of semi-finished
product solidification during continuous cast, based on finite difference method. To validate the model,
we have developed a simulation program, which had obtained important results by running comparable with the
experimental results. The proposed method of modeling and simulation allows a sufficiently accurate
analysis of the phenomenon of crust formation and hence the formation of solidification cracks. Although
we can use it only off-line, it derives essential information necessary for designing neural system for
detection of cracks and the drawing up fuzzy decision system bases rules to determine the weight correction
for the cooling water flow rate and primary casting.
Keywords: analytical identification, simulation, solidification, finite difference method,
Microcontroller’s Applications in Driving of Industrial Robots
Microcontrollers and microprocessors are distinct in that, to be able to use a microprocessor, one has to
integrate peripheral components like memory chip or data transmitters-receivers, while microcontrollers have
integrated all the necessary components for an autonomous operation. There is no need for additional
external part because all the required ones are already incorporated in microcontroller’s capsule.
Thus using microcontrollers on device construction it can be saved time and space, in terms of geometrical
dimensions. The present paper describes an application regarding driving and controlling a automatic guided
vehicle using microcontrollers. The kinematic curvature is performed using two guiding wheels that have
immobile shafts and distinct velocities.
Keywords: microprocessor, microcontroller, robots, programming, advantages
Sizing of Compression Coil Springs Gas Regulators Using Modern Methods CAD and CAE
Adelin Ionel Tuţă,
This paper presents a method for compression coil springs sizing by gas regulators composition, using CAD
techniques (Computer Aided Design) and CAE (Computer Aided Engineering). Sizing is to optimize the
functioning of the regulators under dynamic industrial and house-hold. Gas regulator is a device that
automatically and continuously adjusted to maintain pre-set limits on output gas pressure at varying flow
and input pressure. The performances of the pressure regulators like automatic systems depend on their
behaviour under dynamic opera-tion. Time constant optimization of pneumatic actuators, which drives gas
regulators, leads to a better functioning under their dynamic.
Keywords: helicoidally spring, CAD, CAE, simulation, finite element
On Dynamic Systems with Piecewise Linear Feature
Impact dynamics is considered to be one of the most important problems which arise in vibrating systems.
Such impact oscillator occurs in the motion with amplitude constraining stop. In the past years, this simple
model has been found rich phenomena and given benefit for understanding of impact systems. Different types
of impacting response, such as periodic and non-periodic oscillations, can be predicted by using
bifurcation diagrams. Many mechanical systems in engineering applications represent systems which are driven
in some way and which undergo intermittent or a continuous sequence of contacts with limiting motion by
constraints. For example, the principles of the operation of vibration hammers, impact dampers, inertial
shakers, milling and forming machines etc, are based on the impact action for moving bodies. With other
equipment, machines with clearances, heat exchangers, steam generator tubes, fuel rods in nuclear power
plants, rolling railway wheel sets, piping systems, gear transmissions and so on, impacts also occur, but
they are undesirable as they bring about failures, strains, and increased noise levels.
Keywords: impact dynamics, oscillation, equilibrum
Improving IT Infrastructure Management Using Nagios Open Source Package
This paper presents results from adapting Nagios software package to the conditions existing at the
University "Eftimie Murgu" Resita, in order to construct an integrated monitoring system of the existing
active communication equipment.
Keywords: Nagios, management, IT infrastructure
Determination of Double Flexible Toothed Wheel Length Function of Elasticity Module (E)
This paper presents the length determination modality of the double flexible toothed wheel from a
toothed harmonic transmission having a wave generator with π/2 phase difference, function of the
material’s longitudinal elasticity module.
Keywords: harmonic double transmission, wave generator with π/2 phase difference