Santa Tecla, El Salvador

Polytechnic University of El Salvador
Santa Tecla, El Salvador
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Gulyayev Y.G.,National Metallurgical Academy of Ukraine | Mamuzic I.,University of Zagreb | Shyfrin Y.I.,Tube Metallurgical Company | Bursak M.,Polytechnic University of El Salvador | Garmashev D.Y.,OJSC INTERPIPE NTZ
Metalurgija | Year: 2011

The article first give a review more of hundret years long history of seamless steel tube production, especially during the last 15-20 years of the 20th century. Prolongation, article give technological indices for 4 mills (automatical, continuous mill, pilger, Assel), and perfectation of processes seamless steel tubes production at the begining of 21st century.

Harnicarova M.,Polytechnic University of El Salvador | Zajac J.,Polytechnic University of El Salvador | Stoic A.,Josip Juraj Strossmayer University of Osijek
Tehnicki Vjesnik | Year: 2010

The paper deals with a comparison of the most frequently used thermal cutting technologies appliedtothe structural, low carbon steel ENS355J0 inengineering enterprises with a focus on experimental measurement and evaluation of characteristics of the heat affected zone. It gives a mutual comparison of these technologies in terms of the achieved heat affected zone.The goal of this paper wastouse the property changesinthe used material (affectedbylaser, plasma arc and oxygen cutting)asthe quality indicator of the cutting process.

Fedorko G.,Technical University of Košice | Molnar V.,Technical University of Košice | Marasova D.,Technical University of Košice | Grincova A.,Technical University of Košice | And 4 more authors.
Engineering Failure Analysis | Year: 2014

The most common case of conveyor belts damage is their puncture by falling sharp material. One of the ways, how to minimize this type of damage, is using of suitable type of conveyor belt. Therefore, the analysis of conveyor belts on the part of their puncture resistance is an important factor for their use in operation conditions. The aim of the paper is to determine the dependence among the weight of sharp material falling on the conveyor belt, shatter height and force conditions in the conveyor belt on the base of experimental measurements by the help of regression mathematical model and to determine conditions under which the conveyor belt is damaged. The experimental results enable the operator of a conveyor belt to set the shatter height and maximum weight of falling weight below the threshold values in order to prevent conveyor belt damage. © 2013 Elsevier Ltd.

PubMed | Czech University of Life Sciences, Polytechnic University of El Salvador and University of El Salvador
Type: | Journal: SpringerPlus | Year: 2016

Field monitoring and laboratory results are presented for an unsaturated volcanic pyroclastic. The pyroclastic belongs to the latest plinian eruption of the Ilopango Caldera in the Metropolitan Area of San Salvador, and is constantly affected by intense erosion, collapse, slab failure, sand/silt/debris flowslide and debris avalanche during the rainy season or earthquakes. Being the flowslides more common but with smaller volume. During the research, preliminary results of rain threshold were obtained of flowslides, this was recorded with the TMS3 (a moisture sensor device using time domain transmission) installed in some slopes. TMS3 has been used before in biology, ecology and soil sciences, and for the first time was used for engineering geology in this research. This device uses electromagnetic waves to obtain moisture content of the soil and a calibration curve is necessary. With the behavior observed during this project is possible to conclude that not only climatic factors as rain quantity, temperature and evaporation are important into landslide susceptibility but also information of suction-moisture content, seepage, topography, weathering, ground deformation, vibrations, cracks, vegetation/roots and the presence of crust covering the surface are necessary to research in each site. Results of the field monitoring indicates that the presence of biological soil crusts a complex mosaic of soil, green algae, lichens, mosses, micro-fungi, cyanobacteria and other bacteria covering the slopes surface can protect somehow the steep slopes reducing the runoff process and mass wasting processes. The results obtained during the assessment will help explaining the mass wasting problems occurring in some pyroclastic soils and its possible use in mitigation works and early warning system.

This paper is focused on the area of motivation and motivational programs for employees in the wood industry and in other manufacturing enterprises (engineering, food, chemical and textile). The main objective of this paper is to compare the motivation of employees with in manufacturing companies of various categories. We analyzed the current state of motivation of employees within manufacturing companies throughout Slovakia. The analysis was made of 21 enterprises with 2 576 employees in different job positions. The order of importance was made for 30 selected motivational factors in wood industry and other manufacturing enterprises. The evaluation of statistical correlation between the two compared groups was made by use of the Spearman correlation coefficient, by which statistical dependence was defined between the category of workers and the category of technical-economic employees. The results show fundamental difference of the importance of motivational factors within technical and marketing staff of woodworking companies and other manufacturing companies. In the category of workers, diversity of the importance of motivational factors is less significant. Our analysis showed that in a long period of time all employees keep their motivation at a constant level.

Wilczek A.,Polish Academy of Sciences | Szyplowska A.,Polish Academy of Sciences | Skierucha W.,Polish Academy of Sciences | Ciesla J.,Polish Academy of Sciences | And 2 more authors.
Sensors (Switzerland) | Year: 2012

This paper presents the application of a frequency-domain reflectometry (FDR) sensor designed for soil salinity assessment of sandy mineral soils in a wide range of soil moisture and bulk electrical conductivity, through the determination of soil complex dielectric permittivity spectra in the frequency range 10-500 MHz. The real part of dielectric permittivity was assessed from the 380-440 MHz, while the bulk electrical conductivity was calculated from the 165-325 MHz range. The FDR technique allows determination of bulk electrical conductivity from the imaginary part of the complex dielectric permittivity, without disregarding the dielectric losses. The soil salinity status was determined using the salinity index, defined as a partial derivative of the soil bulk electrical conductivity with respect to the real part of the soil complex dielectric permittivity. The salinity index method enables determining the soil water electrical conductivity value. For the five sandy mineral soils that have been tested, the relationship between bulk electrical conductivity and the real part of dielectric permittivity is essentially linear. As a result, the salinity index method applied for FDR measurements may be adapted to field use after examination of loam and clayey soils. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Hladky V.,Polytechnic University of El Salvador | Bielek R.,Polytechnic University of El Salvador
Advances in Electrical and Electronic Engineering | Year: 2014

Work presented here deals with the modelling of thermal processes in a thermal system consisting of direct and indirect heat exchangers. The overall thermal properties of the medium and the system it self such as liquid mixing or heat capacity are shortly analysed and their features required for modelling are reasoned and therefore simplified or neglected. Special attention is given to modelling heat losses radiated into the surroundings through the walls as they are the main issue of the effective work with the heat systems. Final part of the paper proposes several ways of controlling the individual parts' temperatures as well as the tem perature of the system considering heating elements or flowage rate as actuators. © 2014 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING.

Kandrik R.,Polytechnic University of El Salvador | Olah B.,Polytechnic University of El Salvador
Moravian Geographical Reports | Year: 2010

Land use developments and changes in the central part of the Spiš region since the 18th century are discussed in this paper. Using the ArcGIS 9.x software, available aerial photographs and historical maps were processed and land use categories were identified for five points in time. The areas with stable land use, as well as those with various intensities of land use change, were assessed. The main trends in land use and their locations were identified. The analysis revealed several similarities with comparable neighbouring regions, but also some regional specification. © INSTITUTE OF GEONICS ASCR, v.v.i. 2010.

Stofa J.,Polytechnic University of El Salvador | Michalik P.,Polytechnic University of El Salvador | Zolotova I.,Polytechnic University of El Salvador
Lecture Notes in Business Information Processing | Year: 2013

This paper considers access to issues of enterprise related to the social web. Justifies the importance of this relationship and compares three ways of interaction. The paper looks on an employee as a risk factor threatening the security of the enterprise and deals options of monitoring and its monitoring instruments. Corporate marketing in relation to the social web can be deal by the support of opinion mining. The paper is an introduction to the security of company integrated in a social web. © Springer-Verlag Berlin Heidelberg 2013.

Bernathova I.,Polytechnic University of El Salvador | Bursak M.,Polytechnic University of El Salvador
Metalurgija | Year: 2011

The properties of ultra fine grained nano Titanium made by ECAP technology and pure cold drawn Titanium are analyzed in this contribution. Mechanical properties, resistance to wear by a ZrO2 ball friction test, corrosion in a Hank solution by the Tafel's method at temperatures 21 °C and 37 °C, and fatigue properties in torsion were evaluated and compared. The fatigue fracture started with crack formation parallel to the specimen axis and it was finalized by cracking in the angle of maximum shear stress. Titanium powder has been observed on the sample surfaces which indicated the crack initiation. Nano structure Titanium showed higher resistance to corrosion less wear by friction, and to a limited number of cycles higher fatigue strength.

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