Journal AUEMR Vol. 25

Analele Universităţii
"Eftimie Murgu"
Reşiţa
Fascicula de Inginerie

ISSN-L 1453-7397
Printed version ISSN 1453-7397
Online version ISSN 2344-4568

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Analele Universitatii "Eftimie Murgu" Resita. Fascicula de Inginerie

Vol. 27, No. 1 (2020)

TABLE OF CONTENT

ARTICLES

Simulation of a waiting system
Olga-Ioana Amariei, Codruta-Oana Hamat

This paper analyzes an existing production system in an industrial hall, consisting of 11 machines (service stations) and 13 intermediate stocks (queues), where 4 types of parts are processed and assembled, with the aim of increasing production volume. The Queu-ing System Simulation module of the WinQSB software is used, which allows the simulation of waiting systems.

Pages: 9-20

Research on the quality of welded joints of P265GH heat-resistant steel pipes for electron beam mechanized welding
Lenuta Cîndea, Vasile Iancu

TThis paper analyzes the quality of welded joints of high temperature resistant steel pipe at electron beam welding, knowing that the mechanical properties of these types of steels are influenced by the interaction of different processes specific to physical and mechanical metallurgy. Analyzing the values of the local hardening estimator ΔHV10 calculated between the characteristic areas of welded joints, it is observed that it has a decreasing tendency at thermally de-stressed joints, in all areas of the welded joints, especially in the welded seam.

Pages: 21-28

Simulating an improved algorithm for propagation of transverse oscillations through a string
Cornel Hatiegan, Mihaela Dorica Stroia

In present paper we bring under discussion a mathematical algorithm for determining oscillations through an elastic string. We have noticed that the algorithm has a flaw which can be solved by introducing an approximation into the system. For improved algorithm we have developed a program in order to obtain a simulator for propagation of transverse oscillations through a string, which allow us to obtain graphical representations for n order harmonics.

Pages: 29-36

Contributions to the synthesis and modeling of gear wheels geometry of a double harmonic transmission
Draghita Ianici, Sava Ianici

The paper presents the geometric synthesis and modeling of the geometry of the three gear wheels (flexible, fixed rigid and mobile rigid) of a double harmonic transmission. The geometric design of the wheels and their teeth was made by using particular relationships that resulted by imposing the specific conditions of harmonic engagement that exist between these wheels.Modeling of the 3D geometry of the wheel gears of the considered double harmonic transmission was performed in the SolidWorks CAD program, based on the geometric parameters resulting from performing the geometric synthesis.

Pages: 37-44

Study of the influence of intermittent motion on the orientation kinematic precision of a double harmonic transmission
Sava Ianici, Draghita Ianici

The paper presents a method and an experimental installation, designed by the authors, for determining the orientation kinematic precision of a double harmonic transmission (DHT). The influence of repeated stops and then continued motion on the orientation kinematic precision of the DHT was researched. The study of the orientation kinematic precision of DHT was performed by taking into account 5 torque steps of DHT, at a constant speed of the driving shaft and maintaining its same direction of rotation. Experimental investigations have shown that the instantaneous transmission ratio of the DHT does not vary significantly from its nominal value and that the orientation kinematic precision of DHT decreases with increasing transmission torque.

Pages: 45-50

The study of the elastic deformation of a flexible wheel by a cam wave generator
Sava Ianici, Draghita Ianici

The paper presents the geometric synthesis and modeling of the geometry of the three wheel gears (flexible, fixed rigid and mobile rigid) of a double harmonic transmission. The geometric design of the wheels and their teeth was made by using particular relationships that resulted by imposing the specific conditions of harmonic engagement that exist between these wheels.Modeling of the 3D geometry of the wheel gears of the considered double harmonic transmission was performed in the SolidWorks CAD program, based on the geometric parameters resulting from performing the geometric synthesis.

Pages: 51-58

Sacredness to desecration: ‘Languaging’ and ‘othering’ of peoples and places through dumping of domestic waste in Urora, Benin City, Nigeria
Hope Iyawe

This paper examines the dynamics of environmental change of physical spaces and the behaviour of the residents of a formerly close-knit community whose belief systems are contrary to their lifeworld situation as observed in Urora settlement in Benin City, Nigeria. The findings revealed that the satellite images show that the study area was much greener 20 years ago and environmentally attractive compared to the current time. Lack of infrastructure such as waste bins has led to a shift in mindset among the residents to accommodate illegal dumping contrary to attitudes in the past. Population growth and refuse generation and disposal is also a significant challenge. Based on the findings, the paper posits for the realignment and reconsideration of the embodied sacredness of nature with the mode of expression of the past which was pro-environmentally inclined and focussed.

Pages: 59-68

Opportunities to tackle apathy in solid waste management in rural integrated urban environment: The case of the Urora community in Benin City, Nigeria
Hope Iyawe, Obas John Ebohon

In sub-Sahara African countries, there exists apathy towards solid waste management and services. Indiscriminate waste disposal in Urora is addressed through a recent study which uses a combina-tion of concepts from the sense of community, empowerment and phenomenological principles to explore how to engage households with other stakeholders to address the disconnect that has resulted in environmental degradation. The findings revealed that the problem of indiscriminate waste disposal in this community could not be meaningfully understood without understanding their communal living, behaviour and practices as mediated by rituals unmitigated by passage of time. Based on these results, this paper argues that ‘living in the community’ means taking an active part in the settle-ment’s physical environments for effective income generating opportunities.

Pages: 69-78

Heat absorption and Hall current effects on unsteady MHD flow past an inclined plate
Gaurav Kumar, S.M.K. Rizvi, Amresh Kumar

In the present paper, we study the effect of heat absorption on unsteady flow of a viscous, incompressible, electrically conducting fluid past an impulsively started inclined plate with variable wall temperature and mass diffusion in the presence of transversely applied uniform magnetic field and Hall current. Earlier we analyzed the effects of radiation and chemical reaction on MHD flow past a vertical plate with variable temperature and mass diffusion. We had obtained the results which were in agreement with the desired flow phenomenon. To study further, we are changing the model by considering heat absorption on fluid, and changing the geometry of the model. Here in this paper we are considering the plate positioned inclined from vertically plane and impulsively started with velocity u0. The temperature of plate and the concentration level near the plate is increase linearly with time. The governing equations involved in the present analysis are solved by the Laplace-transform technique. The results obtained have been analyzed with the help of graphs drawn for different parameters like thermal Grashof number, mass Grashof Number, Prandtl number, permeability parameter, Hall current parameter, heat absorption parameter, magnetic field parameter and Schmidt number. The numerical values obtained for skin-friction and Nusselt number have been tabulated. The results are found to be in a good agreement and the data obtained is in concurrence with the actual MHD fluid flow phenomenon.

Pages: 79-95

A Python application to generate digital signals
Tatian-Cristian Mălin, Dorian Nedelcu, Gilbert-Rainer Gillich

We introduce in this paper an application developed in the Python programming language that can be used to generate digital signals with known frequencies and amplitudes. These digital signals, since have known parameters, can be used to create benchmarks for test and numerical simulation. The application was initially created to test the accuracy of another application that calculates the derivatives and the antiderivatives of a signal.

Pages: 96-104

Static and dynamic tests at a railway tank wagon
Tiberiu Stefan Manescu , Nicusor Laurentiu Zaharia , Constantin Ioan Baribnta

Railway tank wagons are widely used for the transportation of liquid cargo as petroleum products, acids, alcohol etc. During the last years only tank wagons with bogies were manufactured (four axles wagons). The prototype of each wagon’s series is tested ac-cording with international standards in purpose to validate the design (the project). This paper present the static and dynamic test performed at the body of a four axles tank wagon.

Improvement of Jain’s algorithm for frequency estimation
Andrea Amalia Minda , David Lupu , Gilbert-Rainer Gillich

In this paper we propose a procedure to correct Jain's algorithm, which in certain situations fails in correctly estimating the frequen-cy by indicating frequency values that are very far from the real frequency. It happens because the two points considered for the method proposed by Jain are not on the same lobe. Thus, a method is proposed according to which these points are chosen so that the results are improved.

Study for monitoring of the insulation stator winding of the hydro generators using a data acquisition system
Mihaela Molnar , Eugen Răduca

The paper presents a study for a system for data acquisition in order to monitor online the state of the insulation stator winding of hydro generators, using the LabVIEW graphical programming language. The data acquisition system allows the acquisition of the quantities of interest in the process and at the same time, through it, the creation of a strong database for the current state of the hydro generator insulation.

Three-Axis Level with WiFi Connection
Cristian-Mircea Muscai , Ion-Cornel Mituletu , Tiberiu Manescu , Bogdan Protea

The Three-Axial Level (TAL) device measures the angular inclination around the three axes of the orthogonal system. It consists of a triple-axis magnetometer sensor with I2C transmission and a NodeMCU V3 development board with WiFi module integrated. The device processes data from sensor, displays it on its screen and also transmits the angular values to various PADs (Portable Access Device). The experimental testing confirmed the initial expectation, showing the properly on-site operation of the designed device. This device is useful in the supervising process to avoid perturbing the worker that performs the leveling operation or when the working place is hard to reach.

Pages: 129-136

Estimation of the severity of damage produced by a transverse crack
Marius-Vasile Pop , Gilbert-Rainer Gillich , Cristian Tufisi , Zeno-Iosif Praisach , Lucian Paun

This paper presents a method to find the severity of a crack for cantilever beams that can be used to estimate the frequency drop due to the crack. The severity is found for the crack located at the location where the biggest curvature (or bending moment) is achieved. Because the fixing condition does not permit a symmetrical deformation around the crack, the apparent severity is small-er as the real one. The latter is found by the estimated value of the trend-line at the fixed end, it being constructed on points that con-sider the crack position (equidistant points in the proximity of the fixed end) and the resulted deflections.

Deflection of a beam with a transverse crack under dead load
Marius-Vasile Pop , Zeno-Iosif Praisach , Gilbert-Rainer Gillich , Lucian Paun

This paper proposes an analytic relation for the deflection of a cantilever beam with a transverse crack subjected to dead load. The mathematical relation is deduced involving the decreased capacity of the beam to store energy, which is in direct relation with the crack position and depth. Eventually, the validity of the relation is proved by means of the finite element method.

Prediction of power cables failures using a software application
Marius Florian Predus , Elisabeta Spunei , Monica Rosu

This paper analyses the electrical performance of power supply cables in operation by investigating previous faults and forecasting faults using the Easyfit Professional 5.6 software program. The calculation of the maximum operating time until the first fault oc-curs is based on an algorithm for estimating the parameters entered in the application, respectively the intervals of good operation time between two successive faults. The case study presented in the paper analyses the probability of failure of a medium voltage power line, under the administration of a distribution operator, based on information collected during maintenance work on medium and low voltage installations in the analysed area.

Model of microprocessor centrifugal equipment for honey extraction
Eugen Răduca , Mihaela Molnar , Nicolae Titu Fara

The paper presents a model of centrifugal equipment for extracting honey made around an ATmega 328 processor, with which the Ar-duino Uno module is equipped. The created model is functional, being tested, and the practical results obtained would allow the transition to prototype equipment. The created model is flexible, al-lowing to obtain flexible operating cycles, with variable speeds, soft settable, in both directions of rotation. The number of frames from which the bee honey can be extracted is variable depending on the juicer itself, which is driven by the motor.

Prediction of power cables failures using a software application
Elisabeta Spunei , Ion Piroi , Florina Piroi

This paper analyses the electrical performance of power supply cables in operation by investigating previous faults and forecasting faults using the Easyfit Professional 5.6 software program. The calculation of the maximum operating time until the first fault oc-curs is based on an algorithm for estimating the parameters en-tered in the application, respectively the intervals of good opera-tion time between two successive faults. The case study presented in the paper analyses the probability of failure of a medium voltage power line, under the administration of a distribution operator, based on information collected during maintenance work on medium and low voltage installations in the analysed area.

Virtual instrument designed for data acquisition
Mihaela Dorica Stroia , Cornel Hatiegan , Cristinel Popescu

Current software development directions open up a world of possibilities, especially in the engineering field. Present paper is meant to highlight the advantages and in particular the ease of using virtual instrumentation facilities, with a proper and adequate design and implementation of desired instrument. In this idea we bring into discussion a design for virtual instrument which can be used for data acquisition that can be stored for further simulations according to the needs required by the process in discussion.