bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal and fluid-dynamic analysis of an automotive disc brake with ventilation pillars aerodynamic type
Authors: Rivera-López J E , García-León R A , Quintero-Orozco A , Diaz-Torrez E J , Gutiérrez-Paredes G J , Echavez-Diaz R , Arévalo-Ruedas J H 
Published: November 2019

AbstractThe braking system of a car must work safely and predictably in any circumstance, which implies having a stable level of friction, in any condition of temperature, humidity and salinity of the environment. For a correct design and operation of the brake discs, it is necessary to consider different aspects, such as the geometry, the type of material, the mechanical resistance, the maximum temperature, the thermal deformation, the cracking resistance, among others. The objective of this study was to analyze the behavior of temperature, velocity and heat flow, in the ventilation duct of an automotive disc brake with ventilation pillars different from conventional using computational fluid dynamics. The SolidWorks Simulations design software was used to analyze the behavior of the fluid (air) in terms of speed and heat dissipation capacity. The numerical results for the heat flow through the ventilation channels were compared with the results obtained mathematically. The numerical results showed that the discs performed well under severe operating conditions. In the design of the brake disc is very important to select the appropriate geometry, particularly the number and the cross section of the ducts in addition to that, the type of material. Numerical methods offer advantages through the software tools for selecting geometry and material and for modeling fluid flow to optimize heat dissipation to provide maximum performance for properly maintained components.
Optimization of the connecting rod of a two-stroke engine using finite element analysis
Authors: Valero-Páez L B , Chacón-Velasco J L , González-Estrada O A 
Published: November 2019

AbstractIn this work, the mechanical behavior of a connecting rod of a two-stroke single-cylinder engine is studied by means of finite element analysis to reduce its weight. We investigated the static and dynamic stresses on the parts of the connecting rod, considering the boundary conditions of the Jovaj theory for the design of automotive conrods. Then, the maximum stresses of the models were compared to perform the optimization of the weight of the connecting rod, evaluating the sensitivity of the prototype, and geometry restrictions. For the study using finite element analysis, a connecting rod prototype designed at Universidad Industrial de Santander was used, within the project of reengineering the connecting rod of a two-stroke engine of small displacement for agricultural applications. The mechanical response of the designed conrod was evaluated, taking into account the mechanical stresses to which it is subjected during the operation of the engine. Finally, the design was revised to propose preliminary improvements in the geometry using topology optimization.
Artificial modelling of unsaturated tests considering the suction control on porous collapsible clay
Authors: Ruge J C 
Published: November 2019

AbstractSoils with a tendency to show phenomena of collapsibility generally have a susceptibility to be controlled by partial saturation, due to its structural configuration which reveal in some cases bonds of cementing minerals, that can be broken in process of wetting. This cementation is governed by the lateritic genesis, as well as for a microporal predominance. Laboratory tests that intend to reproduce the unsaturated condition, need a suction control to simulate properly the levels of stress required in the sample, according with the in-situ stresses presents in the soil mass. However, these tests are difficult to have access to given that they have a complicated assembly and can last several days (even months), due to the benefit in the resistance imposed by the suction on the soil. For this reason, it is extremely important to validate numerically by means of an appropriate constitutive law, at least at the laboratory level, the unsaturated response of a material. In this case a collapsible porous clay of lateritic origin, cause the high dependency of specialized laboratory tests can lead to non-necessaries delayed researches, that can impact in the economy of any project. In this research, an emphasis is placed on the numerical simulation of partially saturated tests through a hypoplastic constitutive model that involves suction in its mathematical formulation. The results are oriented to show the dependence of the suction with the shear strength of the material.
Multicriteria analysis of methane mitigation options on offshore oil and gas production platforms
Authors: Barbosa R , Guimarães C , Serra E , Bellon D , Martínez-Amariz A 
Published: November 2019

Abstract
The oil and gas exploration and production sector are one of the most significant methane emitters through fossil fuel combustion and fugitive emissions. In Brazil, there are few studies focused on the mitigation of methane in the oil sector. The objective of the present work is to use a multicriteria analysis methodology to compare different methane mitigation technologies applicable to offshore oil and gas platforms. In the study, six different mitigation options were compared through the analytic hierarchy process methodology, considering environmental, financial and operational criteria. The results were calculated for each mitigation option considering the scores of each criterion and their respective relative weights, obtained in the prioritization of the elements. This unique score obtained through the analytic hierarchy process made it possible to compare the mitigation alternatives. The alternative that received the best score considering the evaluated criteria was the recovery of vapor from cargo tanks associated with methane reuse, being highlighted mainly due to its high potential for mitigation.
Software to determine the viscosity and honey’s purity using a ball viscometer
Authors: Angelone J P , González N , Adarme J , Rueda S , Cristiano K L , Herrera J R , Triana D A 
Published: November 2019

Abstract
Physics is a science that studies the laws and properties of the universe and everything in it. However, it is more interesting when it is applied to the solution of problems that influence economic and social development. In our case, applied to beekeeping to ensure the purity of honey. Some producers or intermediaries add sugar or water to honey to reduce costs and improve their income affecting the final consumer. Therefore, in this research work, an experimental methodology was proposed combined with the development of software to determine the viscosity of honey with aggregates (sugar and water) and without those, considering that the experimental methodology used here, does not alter the properties of honey. With a ball viscometer and using honey as a viscous medium, times that took metal spheres to pass through the sample tube with different densities were measured. The times were analyzed and synthesized with the application to obtain the viscosity in real-time of the different types of honey, allowing to discern which ones were pure and which had water or sugar aggregates.
Using scattering theory to calculate the ground state energy of lithium atom
Authors: Alcalá Varilla L A , Torres Hoyos F , Pérez Pitalua D L 
Published: November 2019

Abstract
The problem of bound states of atoms with many electrons does not have an analytic solution; therefore, standard methods of approximation are utilized to solve it, and among them, we can find the variational method, the perturbation method and the Hartree Fock method. Said methods may be very difficult to implement and may take a great amount of computational time, even when they are applied to the lithium atom. An alternative method that is considerably easier to implement is proposed in this paper. This involves considering the Hamiltonian for the lithium atom as a collision between an electron and an ionized lithium atom; in this way, the energy of the lithium atom is the sum of energies of a helium atom (with nuclear charge Z = 3) and the energy that an electron needs to be bound to an ionized lithium atom in a collision process. The Quantum Collision Theory under the focus of Jost function was used to calculate the bound state energies of one electron with an ionized lithium atom. Using this approach, we calculated the ground state energy of lithium atom with an error with respect to the experimental value of 0.3%. This error is very low; therefore, the proposed method produces very good results and it can be taken as basis to study atoms with more electrons. Hopefully, In the future, this method could be part of quantum physics books because it is a novel method to observe the formation of atoms.
Computational study of a glow discharge device
Authors: Pacheco Y Q , Barragán Y F , Parada-Becerra F F , Tsygankov P A , Orozco E A 
Published: November 2019

Abstract
The glow discharge is the basis of conventional techniques used to improve the tribological properties of materials, such as the generation of thin films using ionic beams and the sputtering process for the treatment of surfaces. This work focuses on the numerical study of the glow discharge in a system composed of a cylindrical quartz chamber containing argon gas, whose length and radius are 20 cm and 2.5 cm, respectively. Said chamber is limited by two copper electrodes whose potentials are 0 V (Anode) and -500 V(Cathode), respectively. In order to analyze this time-independent discharge, the generation of secondary electrons allowing the discharge to be self-sustained as well as the manifestation of fixed regions, among others, numerical modeling is carried out by using the Plasma Module of COMSOL Multiphysics software. The presented results in this paper can be useful to understand, design and build new technologies focused on the area of treatment of surfaces.
Numerical study of linear plasma dynamics in a spherical tokamak
Authors: López J E , Orozco E A , Dugar-Zhabon V D 
Published: November 2019

Abstract
The magnetohydrodynamic equilibrium is the starting point to study macro- instabilities in a confined plasma; for the particular case, where the system is axially symmetric, the static and stationary equilibrium is due by the Grad-Shafranov equation. We present the equilibrium state for a toroidal plasma confined by a spherical Tokamak with aspect ratio A ∼1.6, total plasma current 1.3 MA and beta parameter β ∼0.35. The Grad-Shafranov equation is solved numerically in a rectangular region of the poloidal plane, using the finite differences method under a successive over-relaxation scheme. Profiles of poloidal magnetic flux, pressure, safety factor and magnetic field are presented. Subsequently, by using the resistive magnetohydrodynamic model, said equilibrium is subjected to perturbations in the velocity to study the dynamics of the plasma in the linear regime. The plasma dynamics simulation is carried out under a fourth order finite difference scheme for the spatial derivatives and implementing the Runge-Kutta algorithm as a temporal integrator. The results show that the perturbations are located in the plasma outer edge; however, some poloidal modes move toward the central zone around the magnetic axis.
Simulation of the electron dynamics in a magnetron sputtering device with equipotential and non-equipotential cathode
Authors: Tsygankov P A , Orozco E A , Dugar-Zhabon V D , López J E , Cárdenas P A 
Published: November 2019

Abstract
The magnetron sputtering of cathode material is one of the ways of producing a thin film deposition on solid surfaces and maintaining the cathode system under a certain potential. Recently, some experimental study of a magnetron sputtering system with the segmented cathode at different electric potential on each segment has been conducted. It allows the system productivity regarding the rate of deposition to be over the volt-ampere current limitations imposed on each segment. The physical processes associated with generating and sustaining it in this system are complex and have not been explained so far from a theoretical point of view. In this work, we present a computational study of the electron dynamics in the simple particle approximation which is found in a two-segments magnetron discharge under the influence of both the magnetic field and the segment electric potentials of 750 V and 500 V. The fields are calculated by using comsol multiphysics ®. The particle dynamics is studied through numerical solution of the Newton-Lorentz equation. The simulations show that the Hall current symmetry is determined by the electrode segments geometry. The obtained results are checked through the simulations fulfilled to maintain the cathode system at the same potential.
Smart operator for the human liver automatic segmentation, present in medical images
Authors: Vera M , Sáenz F , Huérfano Y , Gelvez-Almeida E , Vera M I , Salazar-Torres J , Valbuena O 
Published: November 2019

Abstract
The segmentation of the human body organ called liver is a highly challenging problem due to the noise, artifacts and the low contrast exhibited by the anatomical structures located around the liver and that are present in digital images, generated by any modality of medical images. The main modalities are: ultrasound, nuclear emission, magnetic resonance and the gold standard called multi-slice computed tomography. In this paper, with the objective of to address this problem, we consider multi-slice computed tomography images and we propose an automatic strategy based on two phases. In the first phase, a digital filtering bank is used for diminishing the noise effect and the artifacts impact in the quality of images. In the second phase, called liver detection, we use a smart operator based on least squares support vector machines for generating both the morphology and the volume of liver. The application of this strategy allows generating the morphology of the liver in a precise and efficient manner as it was demonstrated by the metrics used to assess its performance. These results are very important in clinical-surgical processes where both the shape and volume of liver are vital for monitoring some liver diseases that can affect the normal liver physiology.
Left atrial appendage automatic segmentation, in computed tomography images
Authors: Huérfano Y , Vera M , Vera M I , Valbuena O , Gelvez-Almeida E , Salazar-Tores J , Molina V 
Published: November 2019

Abstract
The left atrial appendage is one of the anatomical places where most frequently blood thrombi occur. When migrating from the appendage, these thrombi, become blood emboli that, potentially, can compromise the physiology and/or anatomy of cardiac or cerebral blood vessels, being able to generate cerebrovascular events. The left atrial appendage segmentation is very difficult due, mainly, to its location and the identical densitometric information presents into of this appendage and around of the left atrium. In this paper, an automatic technique is proposed to segment this appendage with the purpose of generating important information to the procedure called left atrial appendage surgical closure. This information is linked to the volume and the diameters of the left atrial appendage. The technique consists of a digital pre-processing stage, based on filtering processes and definition of a region of interest and, of one segmentation stage that considers a clustering method. The results are promising and they allow us to calculate useful quantitative variables when characterizing the most lethal appendix of the human body represented by the mentioned appendage. These results are very important in clinical processes where both the shape and volume of this appendage are vital for detecting and monitoring some vascular diseases such as cardiac embolism, arterial hypertension and stroke, among others.
Usefulness of digital images segmentation in pulmonary transplantation
Authors: Gelvez-Almeida E , Huérfano Y , Vera M , Vera M I , Valbuena O , Salazar-Torres J 
Published: November 2019

Abstract
In the presence of pulmonary pathologies such as chronic obstructive pulmonary disease, diffuse pulmonary disease and cystic fibrosis, among others, it is common to require the removal or replacement of a portion of lungs. There are several requirements for both donors and organ receivers (recipients) established in the literature. May be the main one is the volume that the donor’s lungs occupy in the thoracic cavity. This parameter is vital because if the volume of the lungs exceeds the thoracic cavity of the recipients the transplant, logically, is unfeasible for physical reasons such as the incompatibility between the receiver lung volume and the donor lung volume. In this sense, the present paper proposes the creation of a hybrid technique, based on digital image processing techniques application to raise the quality of the information related to lungs captured in three-dimensional sequences of computed tomography and for generating the morphology and the volumes of the lungs, belonging to a patient. During the filtering stage median, saturated and gradient magnitude filters are applied with the purpose of addressing the noise and artefacts images problems; whereas during the segmentation stage, methods based on clustering processes are used to extract the lungs from the images. The values obtained for the metric that assesses the quality of the hybrid computational technique reflect its good performance. Additionally, these results are very important in clinical processes where both the shapes and volumes of lungs are vital for monitoring some lung diseases that can affect the normal lung physiology.
Semi-automatic detection of the evolutionary forms of visceral leishmaniasis in microscopic blood smears
Authors: Salazar J , Vera M , Huérfano Y , Vera M I , Gelvez-Almeida E , Valbuena O 
Published: November 2019

Abstract
Leishmaniasis is a complex group of diseases caused by obligate unicellular and intracellular eukaryotic protozoa of the leishmania genus. Leishmania species generate diverse syndromes ranging from skin ulcers of spontaneous resolution to fatal visceral disease. These syndromes belong to three categories: visceral leishmaniasis, cutaneous leishmaniasis and mucosal leishmaniasis. The visceral leishmaniasis is based on the reticuloendothelial system producing hepatomegaly, splenomegaly and lymphadenopathy. In the present article, a semiautomatic segmentation strategy is proposed to obtain the segmentations of the evolutionary shapes of visceral leishmaniasis called parasites, specifically of the type amastigote and promastigote. For this purpose, the optical microscopy images containing said evolutionary shapes, which are generated from a blood smear, are subjected to a process of transformation of the color intensity space into a space of intensity in gray levels that facilitate their subsequent preprocessing and adaptation. In the preprocessing stage, smoothing filters and edge detectors are used to enhance the optical microscopy images. In a complementary way, a segmentation technique that groups the pixels corresponding to each one of the parasites, presents in the considered images, is applied. The results reveal a high correspondence between the available manual segmentations and the semi-automatic segmentations which are useful for the characterization of the parasites. The obtained segmentations let us to calculate areas and perimeters associated with the parasites segmented. These results are very important in clinical context where both the area and perimeter calculated are vital for monitoring the development of visceral leishmaniasis.
An ontological model based on the ontology driven architecture paradigm for a middleware in the management of nano-devices in a smart environment
Authors: Lopez-Pacheco A , Aguilar J , Puerto E , García R 
Published: November 2019

AbstractIn this paper is proposed an ontology framework for an autonomic reflective middleware for the management of nanodevices, which is based on the ontology-driven architecture paradigm. In this paper are presented the different levels of the ontology driven architecture model. At the first level, the computation independent model level defines the different ontologies of the nanotechnology domain, like a taxonomy of nanodevices, among others. The second level is the platform independent model level, where are defined the different ontologies for the deployment of the platform, which are the autonomic computation for the autonomous behavior of the middleware, data analytics that describes the analysis process of nanodata, and service-oriented architecture because the autonomic reflective middleware is defined as a multi-agent system oriented by services.
Analytical and experimental determination of gravity and moment of inertia using a physical pendulum
Authors: Cristiano K L , Triana D A , Ortíz R , Pico M , Estupiñán A F 
Published: November 2019

Abstract
Searching to encourage and increase the desire of students to seek a vocation in the study of engineering and science, we wanted to implement and validate experimentally and numerically, the study of the movement of a mechanical oscillator using, in this case, a physical pendulum, formed by a bar and a disk. In this article has done the study the physical pendulum, combining a methodology that involves an experimental arrangement and the implementation of simulations developed in Python, with the aim objective of offering to students a visual and interactive experience, so that they can understand in a simpler way topics covered in the theoretical physics course, in such a way that is different from the typical physical-mathematical formalism. This study was carried out with low cost materials and easy access, in addition to the great social impact that I had against the acceptance and assessment by the students with whom this work was applied. This work was developed in three phases: first, to measure the period of oscillation of a physical pendulum experimentally. Second, the approach of the analytical model to compare with the experimental results. Third, the development of a dynamic simulator according to the predictions of the theoretical model. The students found a didactic and different way of studying the physical pendulum. Finally, it was possible to demonstrate a self-consistency between the experimental and numerical results of the system studied in this work.
Rainwater volume at the Alberto Santos Buitrago school in El Socorro, Colombia
Authors: Torrado K A , Duran L M , Cristancho S L , Quintanilla E , Céspedes E , Tiria L C 
Published: November 2019

Abstract
This study calculated the volume of capturable rainwater over a three-month period at the Alberto Santos Buitrago school in the municipality of El Socorro, Colombia. Rainwater is frequently an under-developed natural resource, due to the minimal investment by public entities, and to the lack of awareness and education of the local inhabitants in this regard. Due to the significant climatic changes occurring across Colombia, however, new interest has arisen in utilizing this resource. The Universidad de Santander, Bucaramanga, Colombia, and the Universidad Libre in El Socorro, Colombia, have joined forces to promote projects focused upon the use of these resources to ameliorate the condition of vulnerable green areas, which tend to deteriorate during dry summer months, as occurred during this study, due to local geographic conditions and the impacted population; in these case young, low-income students of this rural municipality. Such a water storage and distribution system could also serve a valuable role in the school’s sanitary facilities, and for cleaning public areas, with a total of 35.01 m3 of rainwater collected on school roofs. Nevertheless, upon the delivery of the results of the current study, a significant lack of interest was evident on the part of the directors of public institutions in implementing this type of sanitary system. It is thus necessary for the community itself to commit to incentivizing and promoting the implementation and improvement of these new mechanisms.