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Analele Universitatii "Eftimie Murgu" Resita. Fascicula de Inginerie
Vol. 24, No. 1 (2017)
COVER
TABLE OF
CONTENT
ARTICLES
Investigations into the Mechanical Properties and
Microstructural Behavior of Foreign and Locally Fabricated Brake Disc
Basil Olufemi Akinnuli,
Adeolu Adesoji Adedir,
Tunde Claudius Akintayo
The present work reports investigations on mechanical and
microstructural properties of foreign and locally fabricated brake disc.
From safety point of view, brake disc is a crucial component of the
braking system. Foreign brake disc (FBD) are known for their long life
span and better mechanical properties under service condition.
However, locally fabricated brake disc (LFBD) may possess similar or
better mechanical properties than the foreign one. Therefore, the need
to investigate their mechanical properties in order to determine which
brake disc has better mechanical properties under the same service
condition. It was observed that a high machinability index occurs in the
locally fabricated brake disc as compared with the foreign brake disc,
noticeable in the softness and weak graphite flakes formation in the
matrix. Higher resistance to indentation was noticeable in the foreign
brake disc as compared to the locally fabricated disc. The locally
fabricated brake disc however, witnesses about 22% reduction in
toughness compared to the foreign brake disc. An offshoot from this
research will enhance the choice of material selection in the
manufacturing of brake disc and assurance of locally made spare parts
at affordable prices, and the provision of employment opportunities by
establishing spare-parts production and allied industries.
Pages: 7-17
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text
Design and Development of an Unmanned
Surveillance Aerial Vehicle (USAV) Using Locally Sourced Materials
Basil Olufemi Akinnuli,
Olayinka Oluwole Agboola,
Peter Pelumi Ikubanni
An Unmanned Surveillance Aerial Vehicle (USAV) is an air vehicle which
is largely used for surveillance, monitoring, reconnaissance, data relay,
and data collection or to enter an area which is not safe for human.
This study documents the development and evaluation of a low cost,
short range unmanned aerial vehicle to monitor a fixed operational
urban area. Aerodynamic principles were employed to develop a better
concept through reasonable design considerations and assumptions.
The design was then modeled using National Aeronautics and Space
Administration (NASA) Vehicle Sketch Pad (VSP). Analysis of
aerodynamic properties of the wing airfoil section, lift and drag analysis
of resisting surfaces, stability in flight were carried out with the aid of
Computational Fluid dynamics software (JAVA FOIL). Ultimately, in
achieving the goal of this study, the design concept was supported by
the fabrication of a flying prototype.
Pages: 18-32
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Applying a New Method to the Location of the Machines on a Manufacturing Line
Olga-Ioana Amariei,
Codruța-Oana Hamat
In this article, we started from a case study in which we wanted to develop
a proprietary design methodology of lower rank production systems,
using several softwares. Due to its complexity, the study is truncated,
making it the subject of some specialized articles. In this article
the placement of a minimal number of machines is achieved, on which
the technological flow can be achieved unidirectionally, by applying a
new method - AOI method.
Pages: 33-40
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Computer-Aided Manufacturing of 3D Workpieces
Cornelia Victoria Anghel Drugarin,
Mihaela Dorica Stroia
Computer-Aided Manufacturing (CAM) assumes to use dedicated software
for controlling machine tools and similar devices in the process of
workpieces manufacturing. CAM is, in fact, an application technology
that uses computer software and machinery to simplify and automate
manufacturing processes. CAM is the inheritor of computer-aided engineering
(CAE) and is often used conjunctively with computer-aided design
(CAD). Advanced CAM solutions are forthcoming and have a large
coverage, from discrete systems to multi-CAD 3D domain. CAM does
not supersede the necessity of human factor intervention, as production
engineers, programmers or operators, but intercedes the knowledge
of experimented manufacturing engineers by using performant
devices, while enhancing the competences of new professionals by
having access to latest modern equipment. CAM runs along with CNC
machines. The purpose of CAM-CNC system is to reduce as much as
possible the intervention of human factor, thus reducing human error.
The present paper follows to highlight the advantages of CAM-CNC system
on a 3D workpiece manufacturing.
Pages: 41-46
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Optimizing the Cost of Manufacturing Welded
Thermo-resistant Steel Pipe
Lenuta Cindea,
Iuliana Zburlea,
Cornel Hatiegan,
Cristian Rudolf
The presence of stresses in the pipes of unalloyed and low alloyed
steels with characteristics specified elevated temperature (hightemperature)
can be put in the pipe-Dent the deformations occurring in
the welded parts and the knowledge of their size allows to appreciate
the ability of the test structures welded. To remove or reduce residual
stresses and consequently to dimensional stabilization of the parts, use
the thermal process. Comparisons have been made regarding the dimensional
stabilization of the welded assembly by heat treatment of
stress relief and dimensional stabilization by means of low frequency
mechanical vibrations. Starting from the technological flow, two simulations
were performed and the results obtained determined that the
processing times were reduced in the case of vibration stabilization.
The vibration stabilization system decreases thus reducing the manufacturing
costs and consumes only a fraction of the heat demanded by
the heat process, being one of the processes used predominantly for
large welded assemblies, the intent being capable of being chipped at
the place where the process of production.
Pages: 47-54
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Efficiency Investigation on a Helical Gear Transmission
Bogdan Clavac,
Zoltan-Iosif Korka
Gears are extensively used in many applications, such as: automotive,
drive trains, industrial gearboxes and machine tools. They are designed
to transmit power and rotational motion from the input shaft to the
output shaft. In the design process of a gearbox, factors such as: load
capacity, size, lifetime or manufacturing cost are often taken into consideration.
However, precise measures of efficiency are frequently forgotten
issues in the design process. Such shortfalls relate to oil churning,
windage, oil squeezing during gear mesh, or the friction processes
at the level of the gear pairs, seals and bearings. This paper presents a
calculation method used to determine the efficiency of helical gear
transmissions. The method was validated by experimental measurements.
Finally, influence factors on the gearbox efficiency, such as
transmitted load and operating speed are presented.
Pages: 55-66
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Simple Synthesis Method for Alumina Nanoparticler
Daniel Damian,
Florentina Cziple,
Adina Segneanu,
Ioan Grozescu
Globally, the human population steady increase, expansion of urban
areas, excessive industrialization including in agriculture, caused not
only decrease to depletion of non-renewable resources, a rapid
deterioration of the environment with negative impact on water quality,
soil productivity and of course quality of life in general.This paper aims to prepare size controlled nanoparticles of aluminum
oxide using a simple synthesis method. The morphology and
dimensions of nanomaterial was investigated using modern analytical
techniques: SEM/EDAX and XRD spectroscopy
Pages: 67-71
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Harmonics Study of Common Low Wattage LED
Lamps
Ioan Dragos Deaconu,
Alexandru Anghel,
Aurel Ionut Chirila,
Valentin Navrapescu
This article presents experimental data on Light Emitting Diode (LED)
lamps of low wattage that are commonly found both in commercial and
residential applications. A comparison with the existing regulations is
performed. The measurements are performed using power and energy
quality analyzer intended also for avionic and military systems.
Pages: 72-79
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text
Modal-Based Design Improvement of a Butterfly
Valve Disc
Marius Draghiciu,
Zoltan-Iosif Korka,
Gilbert-Rainer Gillich
The dynamic behaviour control of a butterfly valve is important because,
when one of the valve disc natural frequency is close to the frequency
of vortex shedding, which appears when the valve is fully open
or partially closed, resonance may appear and vibration with significant
amplitudes is generated. This paper presents an example by how the
design of a butterfly valve disc can be improved by using a modal
analysis performed by means of the finite element method. For this
purpose, the research reveals the way in which the natural frequencies
of the disc can be modified by applying stiffening ribs or changing the
dimensions, respective the position of these ribs.
Pages: 80-87
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Experimental Measurements of Dynamical Wind
Load acting on the Overhead Transmission Line
Maciej Dutkiewicz
The detailed aim of the study is to determine the distribution of flow
velocity, turbulence, the frequency of detaching vortices. These
parameters are measured for conductor installed in the wind tunnel
and it models the overhead transmission line in wind flow conditions.
Knowledge of these parameters are very important from the
perspective of response of the conductor on wind load excitations
generating the vibrations of the system and the results can be useful in
the design process. Measurements are made for constant air velocity,
fixed turbulence at the inlet of the tunnel.
Pages: 88-100
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Passive Control Solutions Applied to Civil
Constructions under Dynamic Load
Maciej Dutkiewicz,
Vasile Iancu,
Irena Golebiowska
In the paper an overview of passive control solutions used for reduction
of vibration of civil engineering structures is presented and the special
attention is put on the friction pendulum bearings applications as the
example of facility supporting the frame building. The experimental
results of the frame building equipped with friction pendulum bearing
located on the vibration table is studied. The analysis covers the
acceleration response of the frame in time domain as well as power
amplitude spectrum for eleven levels of shaking table's horizontal
excitation movement. On the basis of analysis the clasification of
vibrations of the frame according to earthquake Intensity Modified
Mercalli scale is performed. Discussion on effectivennes of friction
pendulum depending on concave radius of the friction pendulum
bearing and its friction coefficient is performed.
Pages: 101-112
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The Structural Analysis of the Classic Constructive
Solution of a Bridge Deck with a Railroad – Part I
Tudorel Ene,
Dorian Nedelcu
This paper presents the structural analysis of a classic constructive
variant of a bridge deck with a railroad, designed in accordance with SR
1911. The analysis was done using the SolidWorks Simulation software
and focused only on the deck, without taking the pillars into consideration.
The deck was loaded with the weight equivalent of a railroad car.
A study of static analysis was conducted after the 3D structure of the
deck was generated, in order to determine the distribution of tension
and distortion on the deck elements, the areas with the greatest tension
and distortion and solutions to minimize them.
Pages: 113-120
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The Structural Analysis of the Classic Constructive
Solution of a Bridge Deck with a Railroad – Part II
Tudorel Ene,
Dorian Nedelcu
Using the analysis from the first part of the paper [1], the deck geometry
is analyzed on several constructive solutions, which differ in the way
of strut and lonjeron placement and in the way of loads placement. The
optimal solution should take into account the maximum values of tension
and distortion and the number and placement of weldings between
the deck elements. Finally, a comparison between the results of
the classic method and the improved method of the deck geometry is
presented.
Pages: 121-128
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The Impacts of Elevated Carbondioxide (CO2) on
Users’ Comfort in Residential Building at Bawak-Sabo, Auchi, Nigeria
Clement Oluwole Folorunso,
Timothy Ohiosimuan Aigboje
TThis research work establishes the effects of CO2 on users’ comfort in
residential building with specific residential neighborhood in Bawak
Sabo as the study area. There is an existing complaint of sneezing,
tiredness, sweating and headache at dawn from resident of this
neighborhood documented in a medical report of a medical hospital
within the community. The research is set to investigate the cause of
these problems. The methodology adopted was the combination of experimental-
field survey and review of existing literature. Measurement
of CO2 concentration was conducted in a given 10% sample population
(cases). Measurement was taken in tenement and bungalow accommodation
of varied room sizes (9.0m2 and 12.6 m2 floor area), population
(one to two occupants per room) and window opening adjustment.
Measurements were taken 8 hours day time and twilight with varied
user activity and ventilation rate respectively. The results show that
CO2 concentration was higher in rooms with larger numbers of persons.
CO2 concentration was closely related to room size and density and increased
rapidly when doors and windows were locked. Elevated carbondixoide
was low in bungalow accommodation with more numbers of
window openings in comparison with tenement accommodation. Differential
levels of CO2 concentration have negative impacts on the users’
in ways such as shortness of breath, sneezing sweating and increased
breath rate among others. It was concluded that CO2 concentration
was responsible for the reported discomfort experienced by Bawak-
Sabo residents
Pages: 129-140
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Real Time Compensation of the Load Torque for DC
Drive System
Marian Gaiceanu,
Razvan Buhosu,
Silviu Epure,
Razvan Solea,
Cristinel Dache
The objective of this paper is to improve the control quality of the DC
drive system based on Arduino platform. The nameplate DC motor data
are useful to provide the DC motor parameters. The cascade control
loops provides good dynamic performances for the DC drive system. By
using an adequate electric generator, the DC motor is loaded appropriately.
Compared to the conventional control methods, in order to improve
the load torque disturbances, this paper introduces feedforward
load control loop. The simulation and experimental results are shown in
this paper
Pages: 141-148
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Studying the Relative Positions of the Teeth of Conjugated
Wheels in the Double Harmonic Transmission
Draghita Ianici,
Sava Ianici
The paper presents a detailed study of the gearing processes in the
two stages of the double harmonic transmission. To highlight the
graphics of the relative motion of the conjugates teeth it was developed
an original calculation program, written in Visual Basic. By running
the calculation program, the relative successive positions of the
conjugate teeth were viewed and the basic parameters of the gearing
were established: the angle profile (a), the tooth height (h) and the
size of the deformation of the flexible toothed wheel (w0).
Pages: 149-156
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Study of the Deformation of the Flexible Wheel by
Mechanical Generators with Two Deformation Waves
Draghita Ianici,
Sava Ianici
The correct operation and durability of the harmonic gear transmissions
depends to a large extent on the precision of the execution, the
deformation law and the durability of the flexible toothed wheel, the
most requested element of the transmission. In this paper there is
presented a comparative study of the deformation state of the short
flexible toothed wheel of a double harmonic gear transmission for the
case of four types of mechanical generators with two deformation
waves: with cam, 2 rolls, 4 rolls and 2 eccentric discs. By analyzing the
deformation laws of the flexible wheel for the 4 cases of generator
waves, one can achieve a better understanding of how the harmonic
engagement process takes place.
Pages: 157-162
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Investigating the Stress in the Body of the Flexible
Wheel of a Radial Harmonic Transmission
Sava Ianici,
Draghita Ianici
The paper presents a study of the strains and stress state in the flexible
toothed wheel of a radial harmonic transmission, in the case of its
deformation by a 2 roller mechanical wave generator. Dynamic research
has pursued the numerical simulation of a flexible toothed wheel, in the
form of a long circular tube, open at one end, by using the finite element
method and using the SolidWorks Simulation program in elastic
range.
Pages: 163-168
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Experimental Research on Vibrations of Double
Harmonic Gear Transmission
Sava Ianici,
Draghita Ianici
Gears transmission can be important sources of vibration in the mechanical
system structures and can have a significant share in the
overall vibration level. The current trend of significant increase in powers
and speeds transmitted by modern mechanical systems, along with
the size reduction, may cause a worsening of the behaviour of transmissions
with gears in terms of vibration, especially when the optimization
criteria were not respected in the design, execution and installation
phase. This paper presents a study of vibrations that occur in a double
harmonic gear transmission (DHGT), based on experimental research.
The experimental researches revealed that in a double harmonic gear
transmission the vibrations are initiated and develop in the multipara
harmonics engagement of the teeth and in the kinematic couplings materialized
between the wave generator and the flexible toothed wheel.
These vibrations are later transmitted by means of the shafts and bearings
to the transmission housing, respectively, through the walls of it,
propagating in the air.
Pages: 169-174
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Modeling of the Machining Surface Roughness Parameters
for Steel Difficult to Machining
Pavel Kovac,
Borislav Savković,
Marin Gostimirovic,
Dusan Jesic,
Ildiko Mankova
The objective of this study is to examine the influence of machining
parameters on surface finish in turning. A new approach in modeling
surface roughness which uses design of experimentsis described in this
paper. The values of surface roughness predicted by these models are
then compared. The results showed that the proposed system can
significantly increase the accuracy of the product profile when
compared to the conventional approaches. The results indicate that the
design of experiments with central composition plan modeling
technique can be effectively used for the prediction of the surface
roughness for steel difficult to machining.
Pages: 175-183
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Considerations Regarding the Characterization and
Design of Vertical Earth Grounding
Virgil Maier,
Sorin G. Pavel,
Horia G. Beleiu,
Constantin S. Pica
In the paper, five global and synthetic sizes are proposed for the earth
grounding, predestined to represent distinguishing criteria and to justify
the chosen solution: the footprint area, the dispersion surface, the
metal part mass and the earth grounding volume have technical character,
while the investment cost has an economic nature. Resuming the
sizing relationships of earth grounding gives the opportunity to develop
a new nomogram for calculating the dissipation resistance of a single
vertical earth grounding as well as highlighting the quality and quantity
of its specific dependencies. Processed forms are presented in the paper
as well for the use coefficients of the multiple earth grounding, defining
the determination of the electrode number which minimizes at
least one of the proposed global sizes as the main target of the study.
Pages: 184-194
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A Point of View on Optimum Design of Shell and
Tube Heat Exchangers
Feiza Memet
The concept of irreversibility is described based on theory of second
law of thermodynamics. Its understanding followed by the entropy
generation minimization is challenges for specialists. Nowadays
advanced thermodynamics uses the entropy generation rate as a
parameter able to quantify the significance of irreversibilities.
Heat exchangers play a major role in the safety performance and
economy of ships.The aim of this paper is to offer to marine engineers a tool to deal with
optimum design of shell and tube heat exchangers by entropy
generation minimization method. The modified entropy generation
number is considered as the objective function in the minimization
process. Thus, marine engineers’ goal is to minimize the modified
entropy generation number in order to increase effectiveness and to
decrease pressure drop.
Pages: 195-204
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Experimental Determinations on Kinematics of a
Translational Joint of an Industrial Robot
Calin-Octavian Miclosina,
Zoltan-Iosif Korka,
Vasile Cojocaru
The paper presents a 6-DOF industrial robot and the driving system of
its base translational joint. By imposing certain positions of the
translational joint and determining the durations in which these
positions are reached, average speed is computed. The paper shows
how the clearances influence the average speed, depending on the
displacement value.
Pages: 205-210
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Sinc Function based Interpolation Method to Accurate
Evaluate the Natural Frequencies
Andrea Amalia Minda,
Gilbert-Rainer Gillich
Due to leakage phenomena the frequencies and amplitude of the vibration
signals given by the sinc function are not indicated correctly.
There are interpolation methods that solve the problem of frequency
evaluation but which sometimes present significant errors. This paper
presents how the real value can be found if the amplitudes are known
on 3 spectral lines that are in the vicinity of the actual frequency.
Pages: 211-218
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High-speed Microcontroller Based System to Realtime
Analyzing the Mechanical Waves in Structures
Ion-Cornel Mituletu,
Nicoleta Gillich,
Emilian Stanciu,
Codrin-Nistor Nitescu
Nowadays high-speed microcontrollers are employed to accomplish
many applications in different domains, due to their flexible characteristics
and structures. In this paper, the microcontroller algorithm performs
a fast time-frequency analysis by discrete Fourier transform
(DFT) on variable time portions of the vibration signal. System can be
easily customized so that a spectrum with variable range and density is
achieved. Also, the real-time microcontroller based system (R-TMBS)
has been thought as a stand-alone system as well as to be included in
a more complex system, which can function in closed-loop, when the
system feedback is obtained via R-TMBS.
Pages: 219-224
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Wear Resistance Assessment of Fluoropolymer
Coated Gears
Lidia Nedeloni,
Zoltan-Iosif Korka,
Marian-Dumitru Nedeloni,
Dumitru Pauliuc
Power transmissions that incorporate gears dissipate a significant
amount of energy and noise. Thus, any improvement in their performance
contributes to reducing energy consumption and noise pollution.
In recent years, the opportunities offered by conventional technologies
to increase gear performance have been fully exploited. Therefore, surface
depositions on gear teeth have become increasingly important
technologies in achieving objectives such as: improving energy performance,
providing greater protection against superficial defects, increasing
load capacity and reducing acoustic emissions generated during
operation. However, gear coating technologies have begun to be
developed, but the investigations are still insufficient. In this study, we
carried out wear resistance investigations performed on fluoropolymer
coatings for different working speeds, loads and lubrication conditions.
The results point out that the deterioration rate of the coating increases
with the increase of the worki5g speed and the applied load. In
addition, a slight lubrication, applied at the start of testing, leads to a
noticeable improvement in wear behaviour. This study represents one
step further in understanding the wear process of fluoropolymer coated
gears.
Pages: 225-234
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Study Regarding the Good Cavitation Erosion Resistance
of a 13Cr-4Ni Stainless Steel used to Manufacture the Components Exposed to Water of the Hydraulic
Turbines
Marian-Dumitru Nedeloni,
Eugen Birtarescu,
Lidia Nedeloni,
Aurel Bara,
Adrian Pellac
This paper presents some information regarding the hydraulic turbines
respectively the experimental results on cavitation erosion behavior of a
13Cr-4Ni stainless steel used to manufacture the components exposed
to water of the Francis, Kaplan and Pelton hydraulic turbines. So, the
presented experimental results of this paper highlight the good cavitation
erosion resistance of the analyzed 13Cr-4Ni stainless steel.
Pages: 235-246
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Comparative Study on the Cavitation Erosion Resistance
Experimental Results of some Steels Tested through the Cavitation Indirect Method
Marian-Dumitru Nedeloni,
Eugen Birtarescu,
Lidia Nedeloni,
Luminita Hatiegan,
Sorin Laurenţiu Bogda
This paper presents the experimental results of cavitation erosion research
regarding the resistance of some steels. So, the cavitation erosion
researches involve tests of hours for each test. These results are in
tabular form, through charts and pictures presented in this paper.
Pages: 247-256
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text
Energy Efficiency of Technological Equipment at the
Economic Agent by Identifying the Points with Recoverable Heat Potential
Arina Negoitescu,
Adriana Tokar,
Dan Negoitescu,
Codruta Hamat
For an energy-efficient future, the EU needs to step up its efforts to
maximize energy savings. In this context, the paper addresses the
steps needed to establish energy efficiency measures and proposes effective
measures to reduce consumption by recovering large amounts
of energy lost to industrial consumers. The points with the highest recoverable
energy potential have been identified and it is proposed to
install the heat recovery systems on the flue gas exhaust circuits and
polluted air from Industrial Technological Equipment (ITE) such as dyeing/
drying cabins (DDC). Therefore, whenever possible and as small as
energy saving, energy recovery solutions at any level, but especially at
local level, need to be applied. In conclusion, by concentrating all the
energy-saving efforts that are still being wasted, Europe can contribute,
by saving energy, to ensuring a sustainable energy future.
Pages: 257-266
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Aspects regarding the Valorization of the Air Jets
Energy Potential from Industrial Technological Equipment
Dan Negoitescu,
Danut Tokar,
Adriana Tokar,
Arina Negoitescu
In the context of obligations to reduce greenhouse gas emissions to
which EU countries have pledged, reducing energy consumption is a
necessity of the current period. Thus, within Energy Strategy, Romania
was among the first countries that have approved targets for the years
2012, 2015 and 2020. In this respect, the article presents a study regarding
the assessment to an industrial consumer of the energy potential
of the evacuated air jets through the exhaust systems with which
technological facilities are equipped. In order to assess the possibility of
utilizing the kinetic energy of the air jets evacuated by the exhaust systems,
the calculation of the nominal power and power generated by a
600M2 wind turbine was performed. Based on the results obtained during
the air jet speeds recording and of the recovered energy potential,
it can be concluded that the evacuated air jet kinetic energy is a source
that can be converted into electricity for the economic agent own consumption
(insularised system).
Pages: 267-278
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Experimental Procedure to assess Damages of
Welded Beams
Codrin-Nistor Nitescu,
Zoltan-Iosif Korka,
Gilbert-Rainer Gillich
This paper presents an experimental procedure to assess damages of
welded beams, the weld being transversal to the longitudinal beam
axis. It consists of comparing the natural frequencies in intact and
damaged state, calculating the frequency shift due to damage and
weigh the shifts against patterns derived a priori.
Pages: 279-286
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Review of Solid Waste Management Practice, Handling
and Planning in the Construction Industry
Fiza Mohd Noh,
Md Azree Othuman Mydin
The building and construction industry is a major contributor to the
source of national economy. However, inappropriate construction waste
management lead to various problems such as illegal dumping along
the roadsides, demolition waste and disposal of construction at landfills
that Malaysia is facing serious shortage of landfill space and recently
the issue has become more serious throughout the country, which
these have caused major government sources and environmental issue.
Solid waste management is one of the environmental issues which always
been a concerned to most governments. In urban areas, 46% of
the population in the statistics that shows the world population has
reached six billion. In 1997, generation of the municipal solid waste
was about 0.49 billion tons around the globe with an estimated annual
growth rate of 3.2-4.5% in develop nations and 2-3% in developing
countries. The characteristics of solid waste generated were changed
due to the rapid urbanization and industrialization.
Pages: 287-301
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Assessment of Environmental Effects of Noise Pollution
in Auchi, Nigeria
Oyati E.N.,
Stephen A.O.
It is obvious that we are living in a noise-polluted environment. This
pollution has been linked to a number of health related ailments such
as depression, anger, weak concentration and hearing defects. Growing
global population, increase in technological advancement and some
human activities are major causes of this noise-related pollution. This
study investigates environmental effects of noise pollution on man for
possible mitigation strategies. Sound level meter (SLM) was used to obtain
the level of noise pollution in decibel (dB). Selected noisegenerating
centres were used such as mosques, churches, markets,
schools and household appliance-loudspeakers. Noise pollution variables
(NPV) were mathematically-modelled and analysed using statistical
metrics. Sound powers (SP), total power level (SPL) and total sound
pressure level (SPL) were computed using empirical relationship. Reference
power (RF) and pressure (RFP) values of 10-12 watt and 2.0 * 10-5
N/M2 were computed. 230.65dB and 106.3 dB values of SWL were obtained.
These values indicate serious health hazard because it is far
above acceptable standard. The output of the resultant mathematical
iterations indicates that the impact of noise pollution is a cumulative
function of population increase, human activity and technological advancement
at 1% and 5% level of significance. Generally, obtained results
showed that the impacts noise pollution on man and his entire
environment are obviously on the negative side. Hence, possible mitigation
measures such as noise pollution regulatory policy enactment
and design of noise absorbing structures are strongly recommended.
Pages: 302-311
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Simulation and Modelling of Climate Change Effects
on River Awara Flow Discharge using WEAP Model
Oyati E.N.,
Olotu Yahaya
Modelling of stream flow and discharge of river Awara under changed
climate conditions using CLIMGEN for stochastic weather generation
and WEAP model was used to simulate reserviour storage volume, water
demand and river discharges at high spatial resolution (0.5°×0.5°,
total 66,420 grid cells). Results of CLM-Based flow measurement shows
a linear regression with R2 = 0.99 for IFPRI-MNP- IGSM_WRS calibration.
Sensitivity simulation of ambient long-term shows an increase in
temperature with 0.5oc thus the results of the studies generally show
that annual runoff and river discharges could largely decrease. The projection
of water demand 150 million m3 by 2020 against the reservoir
storage volume 60 million m3 and decrease in rainfall depth by -5.7
mm. The output of the combined models used in this study is veritable
to create robust water management system under different climate
change scenarios.
Pages: 312-319
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Numerical Modeling of Transient Heat Transfer in
Longitudinal Fin
Farshad Panahizadeh,
Mohammed Hasnat,
Ashkan Ghafouri
The main objective of the present numerical study is to investigate the
transient heat transfer in one kind of all-purpose longitudinal fin with
the triangular profile. The lateral surface of the concerned fin and the
tip of it are subjected to general situations included heat flux at the
base and insulation on the tip. For this study developed a one
dimensional in house code written by Fortran 90 programming
language by using finite difference method with an implicit scheme in
unsteady state condition. Generally, the result of this study in time
variation state after 700 seconds is steady. The results also show the
fin efficiency by increasing the time of study decreases due to a
reduction in the total heat transfer which is happened in the fin. The
grid independence study shows that for the number of nodes greater
than 20 the result will not be changed and same as before. Finally, the
result of Fortran code verified by commercial CFD code which relies on
finite difference method and it was shown have a consistent agreement.
Pages: 320-328
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Experimental Measurements of Adherence of Thermally
Sprayed Layers
Adrian Valentin Petrica
The bond strength of the thermally sprayed coatings is one of the most
important features in the assessment of deposition quality. Standardized
methods for determining the adhesion of thermally sprayed coatings
refer to the layers deposited on flat surfaces and on the outer diameter
of the cylindrical parts. Thermal spray deposition on internal cylindrical
surfaces is particularly difficult for low diameter. In the case of
inner cylindrical surfaces, one of the parameters that strongly influence
adhesion is the diameter of the parts on which the deposit is made.
The proposed method of measuring the adhesion of thermally sprayed
layers offers concrete values of shear breaking force. This method can
be successfully used especially for experimental samples having a small
internal diameter.
Pages: 329-332
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The Design and Practical Implementation of a
Microwave Generator – ANTITRAUL – Prototype used in Counterterrorist Missions
Silviu Mihai Petrisor,
Raul Alexandru Icleanu
The present paper highlights the way of developing on a scale of 1:1 a
microwave generating device, a prototype that is designed for being
used in the special missions assigned to military engineer specialists to
combat terrorism. This device, used as a psychotronic weapon, can
remotely neutralize various brain centers, thus preventing the terrorist
action to be carried out by the person concerned. The paper presents
in detail the organological construction and the operation of this device,
also pointing out the advantages, the scientific novelty and the
originality of the use of such a prototype in counterterrorist actions.
Pages: 333-337
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Rotation and Radiation Effects on MHD Flow
through Porous Medium Past a Vertical Plate with Heat and Mass Transfer
Uday Singh Rajput,
Gaurav Kumar
Effects of rotation and radiation on unsteady MHD flow past a vertical
plate with variable wall temperature and mass diffusion in the presence
of Hall current is studied here. Earlier we studied chemical reaction
effect on unsteady MHD flow past an exponentially accelerated inclined
plate with variable temperature and mass diffusion in the presence of
Hall current. We had obtained the results which were in agreement
with the desired flow phenomenon. To study further, we are changing
the model by considering radiation effect on fluid, and changing the
geometry of the model. Here in this paper we are taking the plate
positioned vertically upward and rotating with velocity W. Further,
medium of the flow is taken as porous. The plate temperature and the
concentration level near the plate increase linearly with time. The
governing system of partial differential equations is transformed to
dimensionless equations using dimensionless variables. The
dimensionless equations under consideration have been solved by
Laplace transform technique. The model contains equations of motion,
diffusion equation and equation of energy. To analyze the solution of
the model, desirable sets of the values of the parameters have been
considered. The governing equations involved in the flow model are
solved by the Laplace-transform technique. The results obtained have
been analyzed with the help of graphs drawn for different parameters.
The numerical values obtained for the drag at boundary and Nusselt
number have been tabulated. We found that the values obtained for
velocity, concentration and temperature are in concurrence with the
actual flow of the fluid.
Pages: 338-351
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Forecasts of the Maintenance Activity
Marius Romocea
Enhancing the machines’ technical and technological performance
through constructive improvements that allow for the automation of
orders, contributes to the increasing of the production capacity of the
system and for maintaining an optimal level of product costs. In order
to achieve these goals, it is necessary to organize the maintenance
work well, in order to quickly diagnose the malfunctions and to shorten
the repair time. Given the scale of the phenomena, this paper seeks to
answer two questions, namely: how will be the maintenance in future
and also how to prepare this activity.
Pages: 352-355
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Simple and Multi-collision of an Ellipsoid with Planar
Surfaces. Part I: Theory
Nicolae–Doru Stanescu,
Nicolae Pandrea
This paper discusses the problem of simultaneous collisions between an
ellipsoid and some planar surfaces. The approach is one based on the
theory of screws and uses the notion of inertance. The authors consider
that the coefficients of restitution are different for each planar
surface and they obtain the velocities after the collision. An example
concludes the theory.
Pages: 356-371
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Simple and Multi-collision of an Ellipsoid with Planar
Surfaces. Part II: Example
Nicolae–Doru Stanescu,
Nicolae Pandrea
This paper is a complementary one for our previous paper [25]. The
collision of the ellipsoid is considered to take place with the main
planes of the reference system. In our simulation we obtain the following
results: no collision, collision with a single plane, simultaneous collision
with two planes, simultaneous collision with the all three planes,
and collision for a longer time with one or more planes.
Pages: 372-379
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Issues of Semi-automatic Air Processing using a
DCS System
Mihaela Dorica Stroia,
Cornelia Victoria Anghel-Drugarin
It’s well known that trends worldwide are towards automation. We look
for having automatic, or worst case semi-automatic, processes, systems,
machines, with the purpose to produce a finished good in the
shortest time. Consider we have a semi-automatic system used to obtain
air separation. The entire system is ‘supervised’ by a so called DCS
(Distributed Control System) with the role to command several vanes
with different functions. Human factor interferes with DCS only for digital
data input. The system converts digital information in analogical
signals in order to control pressure or flow. The issues of interest addressed
in the present paper concern losses and gains brought by automation
for this particular case of study.
Pages: 380-385
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Special Pattern of Hydraulic Dissipation System
used for Isolation of Bridges against Earthquakes
Fanel Dorel Scheaua
The construction sector experienced a constant evolution over time, so
that today structures can be made to withstand earthquakes of
considerable magnitude. This can be achieved by using various
methods to counteract the direct earthquake destructive action on the
construction. The methods consist of using insulation systems or
earthquake energy dissipation devices that have occurred in time,
being in constant development and improvement. In this paper it is
presented a model of a hydraulic dissipation device as an assembly of a
linear motor with fluid, which can be mounted to the structural frame
of a bridge, in order to take some of the earthquake energy when it
occurs, so that the bridge superstructure is protected against from high
magnitude damages.
Pages: 386-389
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Hydrostatic Devices used for Construction of Seismic
Energy Dissipation Systems
Fanel Dorel Scheaua
Modern structures made today benefit from quality materials that ensure
their considerably long life. In addition to these materials, specific
methods are used in order to counteract the dynamic actions that may
require their structural strength and engineers greatest concern is to
ensure an optimal degree of earthquake stability. Among the methods
are used insulation and dissipation solutions by using special mechanical
systems, which can counteract the earthquake action. A hydrostatic
drive is described in this paper, which can also be attached to the
structure in order to consume some of the earthquake energy, resulting
in a diminished amount of energy transmitted to the structural frames.
It is considered an energy dissipation system, whose operating principle
is highly nonlinear.
Pages: 390-395
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Mechanical Systems based on Dry Friction Force
used for Building Isolation against Seismic Actions
Fanel Dorel Scheaua
Today there are multiple solutions intended to avoid the earthquake
damaging effects on building structures. There are methods based on
the use of special mechanical systems attached directly to the structure's
resistance frames, by means of which an improved building behavior
is achieved during the earthquake. The systems used work on
the principle of structure base isolation based on the dry friction force
(Coulomb friction). Some constructive types of these isolation systems
patterns are described in this paper.
Pages: 396-401
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The Convex Feasibility Problem and Mann-type
Iteration
Irina Maria Terfaloaga
The algorithms for solving convex feasibility problems receive great attention
for their extraordinary utility and broad applicability in many areas
of classical mathematics and modern physical sciences, (for example:
computerized tomography). Usually, the convex feasibility problems
are solved by projection algorithms. The projection method is a
particular case of the Mann iteration process. Numerical examples are
given.
Pages: 402-410
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Statistical Analysis of the Results of Surface
Treatment with Optical Pulses Applied to Parts of Metallic Powders
Ioan Virca,
Danut Eugeniu Mosteanu,
Dorel Badea
Within a wide range of theoretical and experimental research, the
possibility of realizing a new method of superficial treatment of
materials made of metallic powders and the validation of the results
obtained after the treatments were carried out with gas discharge
lamps. The structural transformations carried out in the superficial layer
of the pieces made of metal powders used in the experiments led to a
statistical analysis of the results obtained in this article. Thus, with the
TREND statistical function of Excel program, the evolution of the
changes in roughness was determined, depending on the variable
parameters of the treatment process. The verification was performed
with the ZTEST function by making assumptions about the average
values of selection reported against the critical value of the test. The
results were interpreted on the basis of the phenomena and processes
that occur at superficial level at the interaction of the radiation with the
non-homogeneous layer specific to the pieces made by the aggregation
of powders, consisting of granules and pores. The conclusions
recommend the optimal treatment regimes in order to obtain the
maximum efficiency of the action of the optical radiation pulses emitted
by the gas discharge lamps on the surface of the metal powders.
Pages: 411-417
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Appraisal of Salt Crystallisation and Rising Damp
Problems in Building
Aw Nien Wei,
Md Azree Othuman Mydin
It should be pointed out that salt crystallisation and rising dampness
are two separate but interconnected processes. Both of these damages
must be understood if damage is to be minimized and if corrective
measures are to be successful. However, the term rising damp has
been usually used to cover both aspects, it tends to overlook the role of
salt, and issues that will increasingly significant due to the buildings are
getting older and as the soils are becoming more saline. Hence this paper
will focus on background and an understanding of salt crystallisation
and rising damp problems. Furthermore, the discussion also will include
the indications, causes and effects of both damages.
Pages: 418-428
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Potential and Benefits of Building Information Modeling
(BIM) During Pre-Construction, Construction and Post Construction Stage
Aw Nien Wei,
Md Azree Othuman Mydin
The construction industry is the main economic support for all countries
around the world in which continually adapting to meet competitive
challenges around the global market. Nevertheless, the construction
project is becoming much more complex and difficult to manage. This
is because the construction project involves a large number of stakeholder,
for example, the consultant companies, architects, engineers,
building surveyors and quantity surveyors. The technology currently
used in the construction industry is the AutoCAD (Automatic computeraided
design). AutoCAD is a commercial software application for 2D
and 3D computer-aided design (CAD) and drafting develop by Autodesk.
Generally, all the drawing design from Autocad will be exchanged
among the stakeholder in the form of paper. Information exchanged
among them mostly involves a lot of documents and drawings. This
practice creates errors because of documents and drawings are mostly
in a paper-based format that is not properly managed which results in
miscommunication among them. Having wrong information in the construction
process could hinder the productivity of projects because in a
construction project information is one of the important construction
materials. Building Information Modeling (BIM) is one of the newly
software in the architecture, engineering, and construction (AEC) industries
to ensure all parties receive the right information. BIM technology
is also an intelligent model of a building constructed digitally in
the way of 3D. The software will generate model containing the information
needed to support the construction, fabrication, and procurement
activities that needed to realize the building. This paper will discuss
on potential and benefits of BIM during pre-construction stage,
construction stage and during post construction stage.
Pages: 429-438
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