Analele Universitatii "Eftimie Murgu" Resita. Fascicula de Inginerie

Vol. 26, No. 1 (2019)

COVER

TABLE OF CONTENT

ARTICLES

Models for measuring distances used to obtain optimal locations
Olga-Ioana Amariei, Codruta-Oana Hamat, Daniel-Mihai Amariei

In this paper we propose a protocol for economic decision-making by the management of an industrial enterprise, which wishes to set up a new production unit. The problem is finding the location of the new production unit, which will minimize the total transport cost, consisting of an amount of costs directly proportional to the distances between the new and existing locations. In order to obtain the optimum location, the QSB software package was used, which uses, besides the Manhattan model and the Euclidean and Euclidean quadratic distance measurement model.

Pages: 9-16

full text

Owlet smart control application installed in the public lighting system of Resita
Daniel Brebenariu

The telemanagement system application allows intelligent control of the operation of the ten LED lighting units. Remote operation is done through GSM and through a user-friendly web interface. The dimming levels can be adjusted both manually and automatically. The system is efficient and allows both automatic adjustment of road lighting to predefined levels and savings in electricity consumption. The application also informs the user online about the status of the luminaires it serves, displays the technical parameters and allows to obtain graphs and situations regarding the electricity consumption achieved within a time period chosen by the user. In the application installed in Resita and after one year's monitoring, a 40% saving was obtained compared to ten other lighting fixtures and is not controlled by such a system.

Pages: 17-24

full text

The magnetic field map of the power transformer under extreme operating conditions
Marcel Burduniuc, Ion Stratan, Tudor Ambros

In the paper is done the calculation of the magnetic field of the threephase power transformer with three columns in extreme conditions. The calculation is performed with FEMM application based on finite element theory. The distribution of the magnetic flux from the transformer's magnetic core was obtained. It has been demonstrated the possibility of specifying of the winding and the magnetic system parameters of the transformer.

Pages: 25-30

full text

Inteligent control of a visual attention system based on the chalcogenide glass optical fibers
Veturia Chiroiu, Nicoleta Nedelcu, Valeria Mosnegutu

The chalcogenide ternary thin films should provide efficient solutions to develop the color filter-free image sensors for rapid capture of vivid colors detection of the motion images of a scene in the cognitive processes of perception and interpretation of motion. The image sensor consists of a light-sensitive cell having a lower and a higher electrode. The chalcogenide thin film is placed between the electrodes together with an imaging circuit that measures the wavelength and the intensity of the incident light beam. This paper proposes an easy-to-use, visual attention model that use the filter-less color image sensor to a mobile supervising robot able to detect not only the motion but also the intent and the purpose of the motion. The robot oversees the subjects’ activities, the motion goals and intentions by exploring the eventually dangerous events that could appear during the motion. The feasibility of the proposed attention model has been demonstrated by simulating an example that tracks the dangerous situations on a volleyball game on a playground.

Pages: 31-44

full text

Sensors failure detection and fault tolerance in the complete AAL system
Kristijan Cincar

Ambient Assisted Living (AAL) systems help people to stay active and have a decent life with the help of continuous monitoring for healthcare. Sensors help us to monitor, but the activity of sensors to false positive or negative decay of these monitoring and the status of worships.This work we analyzed detection and tolerance for event triggering sensors in AAL systems.

Pages: 45-48

full text

Applying the simplex method to optimize welding processes of welded constructions
Lenuta Cîndea, Vasile Iancu

The paper contains a study on the optimization of the processes of electric arc welding of welded constructions. A measure of efficiency of the mechanical system has been developed so that it expresses an optimal function, which contains the variables of the system. By quantifying the simplex function, with data from a company with a mechanical profile, one can estimate the degree of success or failure in achieving the proposed purpose. The elaboration of an optimal function leads to a maximum benefit of the mechanical enterprise.

Pages: 45-48

full text

Comparative analysis of dimensional stabilization on welded steel pipes P265GH
Lenuta Cîndea, Vasile Iancu

The paper includes a comparative study on the efficiency of dimensional stabilization of welded stitches in P265GH steel pipes by local-stress relief heat-treatment and low frequency mechanical vibration. Considering the fields of use, these steels must provide high temperature resistance (creep) and ductility, especially elongation and cracking, at high, stable values during the use of the metal structure. Taking a decision on applying stress relieving treatment to a welded structure should take account of certain major factors. Also, depending on the level and distribution of the residual stresses, the volume of the weld structure and its complexity, it will be decided whether the stress will be done totally or locally. Also, one of the drawbacks of applying the method is that stress relieves the manufacturing time and cost of the welded structure. If for a thermally stressed part the duration is 24 hours or more in the case of mechanical vibration stabilization, the time shortens significantly.

Pages: 53-58

full text

Directional kinematics, first step in robotic movement
Ciprian Dragne

Before any robotic decision for moving to a new position, it’s better to evaluate the actual robot position relative to the target, together with any trail obstacles and possible collisions with other object and special zones, or even self-collision during next steps. For this evaluation, the paper is developing a new method for the robot repositioning as a first step or including during the movement a forward or inverse kinematic algorithm with the aim to reduce steps until target location. This new method is named Directional Kinematics because it is addressed to the robot movement relative to a specific direction related to final target location.

Pages: 59-66

full text

Conformity of steel rebar used for reinforced concrete in Nigeria to the British Standards’ Benchmarks
Anthony Nkem Ede, Oluwarotimi Olofinnade, Solomon Oyebisi Akpabot Akpabot, John Oluwafemi, Kehinde Oyeyemi

Selection of construction materials are normally based on their ability to support design loads all through the service life of the structure to be built. For a reinforced concrete structure, the prime choices fall on the quality of concrete and steel reinforcing bars. Concrete is a composite of cement matrix which fills the space between aggregates and binds them together. Concrete quality fluctuates considerably for various reasons such as immense variability of constituent materials’ properties, the skill of the producer, placement procedure and environmental issues. Concrete is universally accepted for its excellent compressive strength. Concrete’s poor tensile strength is normally combined with the high tensile strength of steel reinforcing bar, providing a reinforced concrete composite that is universally accepted for construction. Steel is manufactured in specialized plants and the properties are controlled and certified by the manufacturer. The designer is, therefore, more confident in specifying steel quality complying with a relevant standard, while the choice of concrete mixes is not easy. Nevertheless, concrete and steel complement each other, compensating the weaknesses in the properties of the two materials, thereby making it a universal accepted construction material that has built the world’s most buildings and infrastructure. But due to the frequent cases of the collapse of reinforced concrete buildings and infrastructure in Nigeria, a study of the properties of steel samples available in Nigeria is essential. The scope of this research is on factors that influence the ductility of reinforced concrete, i.e., the properties of steel rebar. This study considers the yield strength and the chemical properties of the three most common diameters of steel rebar used in Nigeria. The results show some deviations in mechanical characteristics and chemical properties of some of the samples. This confirms that some of the samples fell short of the BS codes’ benchmarks for steel rebar.

Pages: 67-75

full text

Analytical investigations on the influence of the geometry of an inertial drive on the propulsion force
Attila Gerocs, Zoltan-Iosif Korka, Gilbert-Rainer Gillich

Since the beginning of the last century, worldwide, researchers and visionaries have spent a lot of time and energy to develop devices capable to use the centrifugal forces for generating linear motion. The present paper presents an inertial driving system designed to produce a propulsion force from the kinetic energy of 8 steel balls which are rotating on an eccentric circular path. The balls are placed between two rotating discs provided with radial slots. After presenting the equations of motion for the steel balls and deducting the propulsion force of the driving system, the paper pays a particular attention to the investigations on the influence of the geometry of the device on the generated linear force. Based on the obtained findings, the authors are confident about the system's ability to produce propulsive force and linear motion.

Pages: 76-85

full text

Improving the precision of the frequencies evaluated with an interpolation method based on maximizer obtained after iterative signal truncation
Gilbert-Rainer Gillich, Vasile Iancu Nicoleta Gillich, David Lupu, Andrea Amalia Minda

Estimating the harmonic components of a signal is based on calculating the signal energy on certain spectral bins that position is defined by the signal time length. Because of this mode of calculation, a difference between the true frequency and the estimate is usually found. In this paper, we present an advanced frequency estimation method, which searches first for the time length for which an entire number of cycles is contained in the signal and afterward calculates the Discrete Fourier Transform (DFT). The results have been found significantly closer to the true frequency as those obtained by a standard DFT applied to the original signal, but it still depends on the number of cycles involved. To further improve the estimation results we propose a methodology to make a correction depending on the number of cycles and sampling frequency.

Pages: 86-92

full text

The Case study of mode shapes and eigen frequencies for a U shaped plate structure
Cornel Hatiegan, Mihaela Dorica Stroia

This paper presents the determining of mode shapes and eigen frequencies of a U shaped plate structure without and with damages using the finite element method of SolidWorks software. The first thirty mode shapes and eigen frequencies obtained by simulations on U shaped plate structure design were determined considering the structure without any damage or with different types of damage. The relative variations of eigen frequencies obtained by simulation using finite element method (FEM) were calculated and a graphical representation was made considering its mode shapes. Finally, the results for all case studies were evaluated.

Pages: 93-98

full text

Contributions to determining the trajectory of a point on the average fiber of the flexible wheel of a double harmonic transmission
Sava Ianici, Draghiţa Ianici

Research on the harmonic transmissions has shown that their functional performances are mainly influenced by the kinematic and dynamic behavior of the flexible wheels in these transmissions. The paper presents a study of the particular aspects of kinematics within a double harmonic transmission. This study aims to present the mathematical algorithm for determining and constructing the trajectories of points located on the average fibers in the two front surfaces of the flexible wheel from a double harmonic transmission. In order to realize the graphical constructions of the trajectories of these points of the flexible wheel, an original calculation.

Pages: 99-106

full text

Unsteady flow past on vertical cylinder in the presence of an inclined magnetic field and chemical reaction
Gaurav Kumar, Aarti Bansal

The chemical reaction effect on unsteady flow of a viscous, incompressible and electrically conducting fluid past an oscillating vertical cylinder with exponentially accelerated wall temperature and variable mass diffusion in the presence of inclined magnetic field is considered. The concentration and temperature level near the surface increases linearly and exponentially with time respectably. The dimensionless governing equations for this investigation are solved numerically by using Crank- Nicolson implicit finite difference method. The velocity profile is discussed with the help of graphs drawn for different parameters like chemical reaction parameter, the inclination of magnetic field, oscillating and exponentially accelerated parameter. The numerical values obtained for skin-friction, Nusselt number and Sherwood number have been tabulated.

Pages: 107-118

full text

Earthquake registration databases
Tatian-Cristian Mălin, Gilbert-Rainer Gillich, Dorian Nedelcu

The retrieval and storage of information from historical earthquake records are very important for the study of seismic activity and the prevention of the danger that earthquakes represent in areas with intense seismic activity. This is possible due to modern techniques and methods of processing, converting old data into digital data and storing them on online databases. This paper presents some important web-based database that provides tools for searching, selecting and downloading ground motion data.

Pages: 119-124

full text

Bearing fatigue studies help to acknowledge many causes of the bearing failures. Nevertheless it is a necessity to analyze the individual bearing components in order to prevent exploitation breakdowns. The current paper aims to evaluate the total energy transfer of the bearing ball collisions that occur during the manufacturing processes.

Pages: 125-132

full text

Experimental determination of forces that occur on a workpiece grasped by a pneumatically driven robotic gripper
Calin-Octavian Miclosina, Zoltan-Iosif Korka, Vasile Cojocaru

The paper presents the manner of determination of forces that act on a workpiece grasped by a pneumatically driven robotic gripper. The starting point consists of experimental determination of the pushing force necessary to move the workpiece held between the gripper's fingers. Then, by using theoretical relations, the friction force between the workpiece and the fingers, and the prehension force (also called gripping force) are computed, for different values of the pneumatic driving system pressure.

Pages: 133-138

full text

A sinc-function based method for frequency evaluation
Andrea Amalia Minda, Gilbert-Rainer Gillich, Ana-Maria Budai

Accurate frequency assessment is nowadays required in the mechanical engineering applications. Because in the standard methods that allow finding the real frequency occur errors, which come from the fact that they depend largely on the acquisition time, we set out to improve these methods. The purpose of this work is to find the maximum amplitude of the interpolation curve that passes through two amplitude peaks on two adjacent spectral lines. The method presented in the paper ensures a high precision when determining the frequency indicated by the maximizer.

Pages: 139-146

full text

Linear displacement measurement by a microcontroller based system
Ion-Cornel Mituletu, Deian-Dorel Ardeljan, Andrei-Viorel Aniţulesei

The paper describes the way of a system dimensioning required to achieve a linear displacement measurement. The system is based on a microcontroller and an incremental encoder. Taking into account the needing of electronic parameter adaptation at the interfacing of the incremental encoder and the microcontroller, a constructive-functional optimization is accomplished. The sensibility of displacement measurement is given by the number of pulses per angular unit, the microcontroller processing and counting speed as well as the efficiency of implemented algorithm and source code. At the dimensioning of electronic circuit is also requested to consider the possibility of perturbation inducing due to the electromagnetic interference of own sources or from environment.

Pages: 147-152

full text

Revitalizing the dead spaces underneath flyover: Potential and issues
Siti Nur Aqilah Amanina Mohd Kassim, Md Azree Othuman Mydin

The increase number of flyovers has resulted in many vacant spaces available underneath the flyover. These spaces are usually forgotten and neglected in the eyes of people in the city. However, the negative consequences produced by flyovers can be minimized through careful design during the construction. Needless to say, this unplanned space could offer abundance of opportunities if being utilize properly. In Malaysia, most people who use negative spaces under flyovers usually does so illegally and those who construct under flyover usually do so without the permission of local authorities and the owner of the land. Hence this paper highlights on potential of utilizing spaces under flyover and some issues related to this grey area.

Pages: 153-160

full text

Commercial value assessment and revitalizing the dead spaces under flyover
Siti Nur Aqilah Amanina Mohd Kassim, Md Azree Othuman Mydin

In recent years, there has been a growth in the population and migration of people from rural areas to urban settings. This phenomenon serves as a contributing factor to the increase number of flyovers. Even though the growth of urban flyovers has optimized the urban transport system and improved the spatial structure of the city, the utilization of space under overpasses has many problems, and they can be dark, short, hostile, and abandoned spaces which are full of girders and include ill-shaped areas in some parts. A huge number of idle and forgotten spaces under the flyovers have been bred. Presently, dark and neglected, that is, the kind of derelict space that lurks below most highways and elevated roadways. Since the number of flyovers has been increasing nowadays, the idea of utilizing spaces under flyovers has become a moot point. The increase number of flyovers also resulted in many leftover spaces available under flyover. These unplanned spaces, if utilized properly, offer an abundance of opportunities. Hence, this study focuses on exploring possible construction and adaptive use of “grey space” under flyover. The case study will be in three main cities which is Penang, Kuala Lumpur and Johor Bahru. This research will be conducted through a combination of site observations, interview and questionnaire surveys. The main objective of this research is to propose three suitable designs for adaptive use of “grey space” under flyover that comply with rules and regulations. As for the conclusion, the size and the location of flyover will determine what can be developed. Hence, without performing any large construction, we will be able to utilize the leftover space under flyover.

Pages: 161-168

full text

Designing a modern drinking water pumping station
Cristian Muscai, Bogdan Protea, Valentin Navrapescu, Monica Rosu

The paper presents a solution for supplying the centrifugal pumps in a pumping station. It starts from the classic power supply of a pumping station with two pumps. The proposed solution consists of using programmable automatons in the control of frequency converters and monitoring the parameters of interest. The use of the proposed solution brings the advantage of easy configuration allows to reduce energy consumption and integrate it into the SCADA monitoring system, including remote monitoring.

Pages: 169-180

full text

The study of the punching cards mechanism with SolidWorks Motion
Dorian Nedelcu, Gilbert-Rainer Gillich, Istvan Biro, Attila Gerocs, Zoltan-Iosif Korka

The objective of the paper is to calculate the velocities and accelerations for some points of the punching cards mechanism and to compare the results calculated through grapho-analytical method with the SolidWorks Motion results.

Pages: 181-190

full text

Design of an electronic device for two-axis balance level measurement
Alexandru Predica, Ion-Cornel Mituletu, Deian-Dorel Ardeljan

This device can be used not only to achieve the parallelism between the surface on which it is fixed and the horizontal plane, but also to accomplish desired tilt angles around the two axis. The device consists of two main components: microcontroller development board and gyroscope sensor. The updating frequency of the displayed values is 10 Hz, these being displayed in the same time for both axes, presenting also the feature of holding the displayed values. At the same time, the device can perform the recalibration, which can also be used for the rescaling to a certain desired angle, thus simplifying the achievement of it. The measurement accuracy is two tenths of a degree, this being high considering the price and the characteristics of the components used. At the end, the designed device is appreciated as being useful, quite simple to implement and easy to operate.

Pages: 191-196

full text

Optimizing maintenance decisions using linear programming
Marius Romocea

Given that the competition between the industrial companies is increasingly tough, the problem of setting up by them of the spare parts manufacturing programs with own resources has become of a great importance. Determining an optimal manufacturing program means setting up a program to ensure, with the material and human resources of the unit, an optimization criterion such as maximum profit, minimal expenses, minimum costs, etc. Next, we present the case where the "profit" optimization criterion is chosen using linear programming.

Pages: 197-204

full text

Potential of lightweight foamed concrete in construction
Anisah Mat Serudin, Shankar Ganesan, Md Azree Othuman Mydin

Progression in construction industry plays an important role to discover advanced methods and technologies for the future. Traditional technology which utilize conventional method in producing concrete has been established and being in use up to now. It used for different applications in construction such as architectural structures, wall partitions, foundations, runaways and highways. However, new innovative materials that can cater for different construction purposes are significant these days. Selection of proper building materials has to be done in order to minimize the energy usage in buildings. In addition, particular attention should be given on thermal insulation and fire resistance properties because low thermal conductive materials will enhance the thermal comfort of indoor environment. Hence this paper highlights on potential of utilizing lightweight foamed concrete in the construction industry.

Pages: 205-212

full text

The method of compensating non-linear effects due to dis-turbing signals in the military operations theatres
Vasile Solcanu,, Marian Gaiceanu

The multitude of disturbing signals from the military operations theatres and battle platforms can lead to the nonlinear operation of radiofrequency (RF) modules in radio receivers with unfavorable effects on the processing of the useful signal. The authors propose in this paper a new way to compensate the operating effects of RF amplifiers in the nonlinear area by introducing a feedback loop based on signal decomposition in reverse power series.

Pages: 213-220

full text

A study on AC efficiency installations on articulated busses
Elisabeta Spunei, Ion Piroi, Florina Piroi

Air conditioning (AC) installed on vehicles must insure passenger comfort no matter the year season. To this end we make a series of measurements and readings of the interior temperature of vehicles with such AC installations. This work presents a study on the AC efficiency on public transportation vehicles, namely articulated busses. Our study shows that the AC appliances installed on the examined busses were not able to ensure the temperature assumed by the AC contractors. We propose that, for public transportation, AC installations should be sized accordingly to the vehicle’s interior volume and to the transportation’s body thermic insulation.

Pages: 221-230

full text

Case studies of auto battery connector behavior subjected to various loads
Mihaela Dorica Stroia, Cornel Hatiegan

In the present paper we present 3D models of three types of components, parts of power supply system found in automobiles. Components were designed and dimensioned according to the needs of their rational exploitation. The three parts under analysis are battery connectors used in petrol or diesel automobiles. Material used for designing is nickel. Case studies consider a comparison between components behavior in terms of von Misses stresses, displacements, elongation, damage, life cycle, load factor or safety factor, when subjected to constraints and different loads.

Pages: 231-238

full text

Device for detecting defects of electric cable with disturbance stability
Serghei Tincovan

This paper deals with the analyses of realization ways of such a low cost device which is resistant to electromagnetic interference and has the improved user service. When repairs are carried out, it is necessary to localize and identify defects in electrical power cables. Most of the known devices for localization and detection of defects in electrical cables are vulnerable to industrial interference, which limits effectiveness and field of application.

Pages: 239-245

full text

Autism friendly classroom to stimulate learning setting
Mohamad Izzat Zulkanain, Md Azree Othuman Mydin

In the present paper we present 3D models of three types of components, parts of power supply system found in automobiles. Components were designed and dimensioned according to the needs of their rational exploitation. The three parts under analysis are battery connectors used in petrol or diesel automobiles. Material used for designing is nickel. Case studies consider a comparison between components behavior in terms of von Misses stresses, displacements, elongation, damage, life cycle, load factor or safety factor, when subjected to constraints and different loads.Sensory integration provides a foundation for more complex learning and behavior. For most of us, effective sensory integration occurs automatically. For many people with autism, the process demands effort and attention with no guarantee of accuracy. Autism Spectrum Disorder (ASD) is referred as a spectrum disorder because each individual has different symptoms, sensitivities and level of functioning. Each of the autistic children’s sensory sensitivities differs from one to another. Specialized design of learning spaces for ASD children may unlock their full potential. Hence this research attempted to design sensory- friendly spaces for children with ASD to stimulate learning environment. The objectives of this research are in 3 folds; (1) to scrutinize the existing body of knowledge to ascertain relevant criteria exist to design space for ASD; (2) to evaluate three centres for children with ASD in relation to the body of knowledge examined; (3) to propose an inclusive design of spaces for children with ASD. Three case studies are chosen for these studies that are Calvary Victory Centre (Johor), Penawar Special Learning Centre (Johor) and National Autism Society Malaysia (NASOM) One Stop Centre (Selangor). Then, six components are identified to be considered in the design of the spaces and four stimuli consideration are identified that is needed to be implemented. So, designing a space that provide conducive environment for these children to use any of their senses comfortably, it may lead to effectiveness in learning process.

Pages: 245-252

full text