Analele Universităţii
"Eftimie Murgu"
Reşiţa
Fascicula de Inginerie
ISSN-L 1453-7397
   Printed version ISSN 1453-7397
   Online version  ISSN 2344-4568

                                                            Issues > Current issue
 
Main
  About the Journal
  Editorial Board
  Scientific Board
  Call for papers
  Subscriptions
  Contact
Issues
  Current Issue
  Archive
Indexed
  EBSCO
  DOAJ
  RePEc
  ProQuest
  IndexCopernicus
  OAJI
  JIFactor
  Global Impact Factor
  CiteFactor
  ImpactFactor
  Academic Journals Database
  WorldCat
  Livre
 

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

 

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

full 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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full 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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full 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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text



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

full text