Revista Técnica de la Facultad de Ingeniería Universidad del Zulia (REV TEC FAC ING UNIV)

Journal description

Publication of the Facultad de Ingeniería, Universidad del Zulia. Mission: Publicar trabajos relacionados con todas las ramas de Ingeniería y las Ciencias Aplicadas.

Current impact factor: 0.05

Impact Factor Rankings

2015 Impact Factor Available summer 2016
2013 / 2014 Impact Factor 0.047
2012 Impact Factor 0.033
2011 Impact Factor 0.05
2010 Impact Factor 0.04
2009 Impact Factor 0.039

Impact factor over time

Impact factor

Additional details

5-year impact 0.06
Cited half-life -
Immediacy index 0.00
Eigenfactor 0.00
Article influence 0.01
Website Revista Técnica de la Facultad de Ingeniería Universidad del Zulia website
ISSN 0254-0770

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Automatic speech recognition (ASR) is the process of automatically transcribing a spoken audio message into text. Besides the fact that the transcription generated by an ASR system is not 100% correct, it is also characterized by low reading intelligibility, because it is not organized in paragraphs, it does not contain any punctuation marks, all text is lowercased, the numbers and dates are written with words instead of digits, etc. This paper reports on the recent advances made by the Speech and Dialogue research group in the field of ASR transcription formatting for the Romanian language. The complete rich speech transcription system developed by our research group is briefly discussed and the transcription post-processing framework, which is responsible for text formatting, is presented in detail. Concrete examples of transcription formatting are given and insightful details on the algorithms designed and used are provided. The impact of transcription formatting and future work is also discussed. © 2015, Revista Tecnica de la Facultad de Ingeniera. All rights reserved.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 12/2015; 38(3):1-11.
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    ABSTRACT: The problem of frequent pattern mining from non-temporal databases is studied extensively by various researchers working in areas of data mining, temporal databases and information retrieval. However, Conventional frequent pattern algorithms are not suitable to find similar temporal association patterns from temporal databases. A Temporal database is a database which can store past, present and future information. The objective of this research is to come up with a novel approach so as to find similar temporal association patterns w.r.t user specified threshold and a given reference support time sequence using concept of Venn diagrams. For this, we maintain two types of supports called positive support and negative support values to find similar temporal association patterns of user interest. The main advantage of our method is that, it performs only a single scan of temporal database to find temporal association patterns similar to specified reference support sequence. This single database scan approach hence eliminates the huge overhead incurred when the database is scanned multiple times. The present approach also eliminates the need to compute and maintain true support values of all the subsets of temporal patterns of previous stages when computing temporal patterns of next stage.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 10/2015; 38(3).
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    ABSTRACT: In the present paper a mathematical model of the cilia induced flow is discussed. The Jeffery fluid model with inclined magnetic field in a two dimensional channel with ciliated walls of infinite length are considered. Mathematical formulation of the present problem is simplified under long wave length and low Reynolds number approximation. The exact solution of the momentum equation and pressure gradient is calculated. Numerical solution is calculated for the pressure rise. The characteristics of the ciliary system on Jeffery fluid model are analyzed graphically and discussed in detail. It was found that pressure gradient increases with an increase in Hartmann number and decreases with an increase in inclination of magnetic field. It was also observed that the size of the trapping bolus increases with an increase in Hartmann number.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2015; 38(2):18-28.
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    ABSTRACT: Let G be an undirected connected graph with n vertices and m edges. If ρ1 ≥ ρ2 ≥ ⋯ ≥ ρn-1 > ρn = 0 are the normalized Laplacian eigenvalues of G , then the normalized linear and ratio Laplacian spreads are defined as NLS obtained. (G) = ρ1 - ρn-1 and NRS(G) = Formula presented , respectively. Lower bounds for NLS(G) and NRS(G) are obtained.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2015; 38(2):13-17.
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    ABSTRACT: A microanalysis was made to evaluate the use of new metallic surfaces to prevent the presence of intergranular corrosion (IC) in stainless steels as SS304 steel. The SS304 steel was used by it low cost compared with other steels of 300 and 400 series, in an experimental process in clean and corrosive environments to compare in both atmospheres. This is to avoid the presence of IC in the metallic industry of the Mexicali city located in the northwest of Mexico, with the evaluated materials because this can generate galvanic cells that are part of the presence of intergranular corrosion, as usually occurs with the presence of chromium material in stainless steels. The analysis of the use of carbon materials mentioned, was made to the experimental development in the process of tempering steel SS304. The study was conducted from 2012 to 2013, comparing the summer and winter seasons for the manufacturing process mentioned and different levels of temperature, relative humidity and concentration of sulfides in addition to assessments of costs of using the materials proposed in the experimental operations. To make the new materials was used the chemical vapor deposition (CVD) and to evaluate the surface of the metals used in the experimentation, was utilized the Scanning Electron Microscopy (SEM).
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2015; 38(2):29-37.
  • P. Wu · S. Xie · J. Luo · D. Qu · Q. Li ·
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    ABSTRACT: The robot path planning is the important element of .the robot navigation. There were several algorithms for obstacle planning, but the most efficient obstacle avoidance algorithm has not been found. So we should continue to research the problem. Artificial Potential Field (APF) and Ant Colony Optimization (ACO) are often used in local and global path planning. However there are some inherent problems, for examples, the problem of GNRON in APF, slow convergence and prematurity in ACO. In order to solve this issue, the global path planning should be compensated by the local path planning. In this paper, we combine the ACO algorithm with Artificial Potential Field (APF)algorithm in goal path planning, and then the modified ACO algorithm can drive the USV to the target. Otherwise, when the environment is changeable, the algorithm switches to the Angle Potential Field method and the robot can escape from the dilemma smoothly. Then the initial global planning algorithm continues to drive the robot to the target. Finally, the simulation results demonstrate that the modified method is with high quality in optimal path planning.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):62-70.
  • S. Zhu · J. Li · C. Wang · L. Yang ·
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    ABSTRACT: Corrosion behaviour of 00Cr13Ni5Mo2 domestic super martensitic steel were investigated under the simulated high temperature and high pressure environments containing high concentration of NaCl solution in the absence and presence of elemental sulphur, weight loss test was utilized to evaluate corrosion degree, the micro morphologies and chemical compositions of corrosion scales were characterised by using Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and X-ray Diffraction (XRD), and pH values of NaCl solution containing different sulphur contents were measured. The results showed that corrosion resistance of super 13Cr stainless steel was aggravated due to the presence and disproportionation reaction of elemental sulphur, and corrosion rate increased with the increasing of sulphur contents. The compositions of corrosion scales changed from oxides to sulfides due to the presence of elemental sulphur, resulting in the change of the semiconductor properties of corrosion scales. Finally, corrosion resistance of super 13Cr stainless steel decreased gradually under the synergies between Cl- and H2S produced by disproportionation reaction of elemental sulphur.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):10-16.
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    ABSTRACT: In order to investigate the hydraulic interaction of pump and flow conduits, CFD method was used to simulate the three-dimensional internal flow of an axial-flow pump system. The performance of the pump system was estimated, and was compared with test data. The rotating impeller has effects on the distribution of axial and tangential velocity components at the inlet conduit outlet, but the numerical values are relatively small. Outlet velocity circulation of guide vane has great influence on flow pattern in the outlet conduit. The flow distribution for both sides of the dividing pier is not symmetric, especially for small flow rate condition. The internal and external performance of outlet conduit has the relationship with the operating condition of the pump system, so it should avoid calculating the flow patterns of a separated outlet conduit. The results show that the hydraulic interaction of flow conduits and pump in different operating conditions is more prominent.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):25-33.
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    ABSTRACT: The paper deals with a model of a switched reluctance motor (SRM) that can be used for the development of control methods for the electrical drives with the SRMs. The non-linear theory describing the behavior of the SRM is listed that uses differential equations including the electromagnetic equations, the electromechanical equations, and the motion equation. On the basis of this theory, there are designed function dependencies of important quantities that are used in the model of the machine. For the verification of the designed model, there was used a control structure using Lyons method that belongs to basic sensorless control methods of the SRM. The sensorless control allows the estimation of the rotor angle and speed. The method is suitable for the area of middle and higher speeds of the SRM. In the paper, there are presented simulation results that show important quantities of the SRM during start and speed reversation.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):114-126.
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    ABSTRACT: This work focuses on the study of real performances of a collective solar water heating system using the remote monitoring technique in Algerian climatic conditions. This is to ensure proper operation of the system at any time, determine the system performance and to check to what extent solar performance guarantee can be achieved. The measurements are performed on an active indirect heating system of 12 m2 flat plate collectors surface installed in Algiers and equipped with a various sensors. The sensors transmit measurements to a local station which controls the pumps, valves, electrical auxiliaries, etc. The system provides a yearly solar yield of 6277.5 KWh for an estimated annual need of 7896 kWh; the yearly average solar cover rate amounted to 79.5%. The productivity is in the order of 523.13 kWh / m2/year. Simulation results are compared to measured results and to guaranteed solar performances. Remote monitoring shows that 90% of the expected solar results can be easy guaranteed on a long period. Furthermore, the installed remote monitoring unit was able to detect some dysfunctions. It follows that remote monitoring is an important tool in energy management of some building equipment.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):105-113.
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    ABSTRACT: When a centrifugal pump operates in flow instability conditions, the dynamic characteristics of the pump change, which is reflected by changes in the statistical properties of its vibration. This paper presents a study on the application of vibration signals to detect the operating condition of centrifugal pumps, by using a statistical analysis method. The statistical features of vibration from the time domain, particularly the rapid increase in peak and root mean square (RMS) values, may indicate flow instability, with the peak indicator being much more sensitive. Most of the extreme points of the crest and kurtosis have obvious physical significance such as the onset and end of the flow instability area, the onset of cavitation, and the maximum efficiency point. The probability density function (PDF) is a good indicator of the early stages of cavitation and could be used to accurately detect the cavitation inception point. Moreover, the statistical features of vibration from the frequency domain, namely the kurtosis, crest factor, and entropy, might be suitable for detecting intensity changes in the broadband noise and discrete frequency peaks in the frequency domain, which are caused by variations in the flow condition. Hence, the statistical analysis of vibration could be an effective method of detecting unstable flow conditions.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):49-61.
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    ABSTRACT: Exploratory data analysis constitutes a challenge for scientists and analysts of multiples disciplines. Most current methods and tools do not allow for analyzing effectively several variables simultaneously. This paper addresses the problem of visual analysis of temporal sequences of multiple variables using multiparameter visualization techniques in geographical information systems. The concepts and methods developed here were implemented as an extension to gvSIG GIS, thus demonstrating the feasibility of this approach for extracting information and knowledge from the original data. A case study with global climate data containing 9 variables with 1224 monthly records from 1901 to 2002 is exposed. Information is given for the 67,420 cells that correspond to the Earth’s land surface, where each cell occupies an area of 25km by 25km. Also, a module for handling scientific data formats was developed for gvSIG that allow storing all information in compact form for effective reading.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):73-82.
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    ABSTRACT: In this article, roll system force analysis has been discussed and static equilibrium equation between rolling force, roll pressure and bending force has been established. Through discrete roll system, influence function of roll system buckling and efficiency coefficient function has been obtained. The objective function of presetting has been established based on deviation of the roll gap crown. The MATLAB simulation and field applications have been made, and the favorable effect has been obtained.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):17-24.
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    ABSTRACT: The adsorption behavior of natural Jordanian volcanic tuff with regard to Cr2+, Cu2+, Pb2+, Fe2+ and Zn2+ was studied in dependence of solution pH in order to assess its practical and economic application for wastewater treatment. A series of batch experiments were conducted using fixed-bed columns under multi changing conditions at different pH values (2, 4, 6 and 7), varying initial solute concentrations (1, 5, 10, 20) mg/L, different temperatures (10 C°, 20 C°, 30 C° ), and varying tuff particle sizes (0.35 -3.5) mm. The filtrate was analyzed using Atomic Absorption Spectroscopy. The breakthrough curves with regard to the absorption of Fe2+ and Cu2+ were obtained under different conditions through plotting the normalized effluent metal concentrations (C/C0) versus absorbent volume. Uptake capacity factor for Fe ions was found to be equal to 0.417 mg/g while that of Cu ions was found to be as much as 0.151 mg/g. Results showed that volcanic tuff is an efficient and low cost ion exchanger and absorbent for removing heavy metals. Results also indicated that an initial solution pH of 2.0 was favorable for obtaining high chromium ions removal, while the pH=4 was deemed to be favorable for lead to be absorbed and removed from the aqueous solution. Equilibrium modeling of the removal showed that the adsorption of the metal ions followed the linear adsorption isotherm.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 04/2015; 38(1):1-9.