bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the propagation of solitary waves produced by an assembly of quantum dots through optical fibers
Authors: Horta S D , Avila D A , Torres C O 
Published: June 2019

Abstract
In this research, the potential use of semiconductor nanostructures as optical field sources to optimize the propagation of lossless pulses along non-linear optical fibers is studied. During this investigation, we propose the external excitation of a set of semiconductor SQD points through a source of optical pulses, giving rise to the generation of solitonic pulses that propagate through an optical fiber with non-linear optical characteristics. Theoretically, soliton formation studied from the non-linear interaction between SQD and external optical excitation. In the study, the non-linear Schrödinger NLSE equation solved numerically using the Fourier Split-Step method to understand the evolution of the soliton emitted for SQD within an optical fiber with real physical parameters.
Ultrasonic spray pyrolysis synthesis of Al, Zr, and Ti oxides multishell
Authors: Hernández L R T , Escalona A , Granados S J , Sánchez A , Orozco S 
Published: June 2019

Abstract
In recent years, core shell nanoparticles have received increased attention due their possible applications in catalysis, biology and materials science. Solid micro-particles with a nanostructure of concentric multilayers were obtained with spray pyrolysis technique. In this work we present the synthesis and characterization of 1 to 10 layers of micro-spheres deposited on commercial brass sheet. Each layer is formed by three films: the first one is made of aluminum oxide, the second of zirconium oxide and the last film of titanium oxide. The films were deposited by the ultrasonic spray pyrolysis technique using organometallic salts of aluminum, zirconium and titanium, employing N, N-dimethylformamide as solvent. Scanning electron microscopy micrographs of 7 and 10 layers shows details about the formation of the layers. The micro-spheres are compacted in a homogeneous and uniform film, whose hardness increases with the number of layers.
Exploring the 2-D Bateman dual system Hamiltonian: a first approach
Authors: Hernández-Saldaña H , Morales-Téllez J , García-Martínez C 
Published: June 2019

Abstract
Dissipation is of major interest in physics and engineering in all energy scales and, hence, it devoted a large amount of investigation. For quantum systems, an usual model for study is the Bateman dual system. Here we use the same model to explore dissipation in angular momentum instead of energy. For that matter, we start with an effective 2-D Bateman model in polar (cylindrical) coordinates and we find the expression for the Hamiltonian. Two constants of motion are found related to modified angular momenta and we test if they are in involution with the Hamiltonian, i.e., if they are integrals of motion. This is in order to verify that the corresponding quantum versions of these constants are good candidates to be a complete set of commuting observables.
Cosmological evolution for magnetic universe based in a simple nonlinear electrodynamics
Authors: Medel-Esquivel Ricardo , Gómez-Vargas Isidro , Rivera-Moltalvo Teodoro , García Salcedo Ricardo 
Published: June 2019

Abstract
We investigate the cosmic dynamics of Friedmann-Robertson-Walker universes – flat spatial sections – which are driven by nonlinear electrodynamics (NLED) Lagrangian. We pay special attention to the check of the sign of the square sound speed since, whenever the latter quantity is negative, the corresponding cosmological model is classically unstable against small perturbations of the background energy density. Besides, based on causality arguments, one has to require that the mentioned small perturbations of the background should propagate at most at the local speed of light. We also look for the dynamics by mean of dynamical system tools. Our results indicate that in the case of the power law NLED Lagrangian, it is not possible to explain the current accelerated expansion stage of the universe because the model is not stable for the possible values of the free parameter that allows such expansion. Finally, in the second case, whose Lagrangian has a power law NLED term plus a Maxwell term, the model is stable and causal for a certain range of values of the free parameter.
Optical characterization of plasmas produced by concurrent application of laser and high voltage pulses
Authors: Alonso A , Sobral H , Robledo-Martinez A , Peña-Gomar M 
Published: June 2019

Abstract
Laser Induced Breakdown Spectroscopy (LIBS) is a simple, powerful analytic technique that is limited by a relatively low sensibility to detect traces. To improve LIBS sensitivity an option often used consists in applying a second source of excitation such as an electric discharge. This work’s goal is to investigate the interaction of a laser-produced plasma on an aluminum target with a self-triggered electric discharge. The plasma dynamics has been investigated using shadowgraphy, fast photography and the application of narrow band-pass filters to follow the evolution of the ionic and neutral species. Results show that within the initial microseconds, the spatial extent of the laser-produced plasma increases due to the presence of a low density region induced by the spark channel. Furthermore, it was found that the electric arc mainly re-excite the ionic species while the neutral ones remains unaffected.
Quantitative evaluation of the transmission spectrum in ophthalmic lenses
Authors: Gómez-Vieyra A , Talamantes-Johnson M A , Chavez-Castillo B A , Miranda-Tello J R , Vergara-Vázquez K B , Belmont-Perez F 
Published: June 2019

Abstract
This paper presents the analysis of the transmission spectrum in four commercial ophthalmic lenses (offered by the company “LensBest”) with different technological characteristics. To evaluate the transmission bandwidth, an experimental setup wich consists on a light source, based on an MSR700 bulb, and was implemented, which provides a UV, visible and near IR emission spectrum. A spectrophotometer was assembled with a Newport monochromator and its corresponding instrumentation. The measurement system was characterized by a sodium discharged lamp, after which a reference measurement of the light source emission was taken. Next, each of the ophthalmic lenses was placed as a sample, with the emission spectrum of the light source and the transmission spectrum of each lens, the comparison in transmission of each element was made. This work allowed us to verify the functionality of each product, as well as validate the characteristics reported by the manufacturer.
Ascending Disk: Theoretical and Numerical Study
Authors: Espíndola R , Valle G Del , Hernández G , Pineda I , Muciño D , Díaz P , Guijosa S 
Published: June 2019

Abstract
In this work we analyzed a classical mechanical problem: a disc with a circular hole rotating and ascending on a inclined plane. The principal idea is to show the basic equations in both Lagrangian and Newtonian formalisms and to present numerical solutions. The equations are not solvable analytically, then we proceed to integrate numerically using the standardized Runge-Kutta method of order 4. We present several phase space showing the time evolution of the system. Additionally we presented an extension of the system considering a damping factor that decays exponentially in time.
Learning Optics from the History
Authors: Repossi P 
Published: June 2019

Abstract
A number of studies have described the benefits of the incorporation of History and Philosophy of Science (HPS) for learning, and teaching science as a process, for promoting conceptual changes, and a deeper understanding of scientific ideas.
Physical Optics is a topic of difficult comprehension, and this fact was also observed at thePontificia Universidad Católica Argentina when students received traditional instruction. This article describes a project to improve the teaching of interference, and diffraction of light within a historical context. Care was taken in developing the line of historical thought, and the study of the hypotheses of the nature of light in proper chronological order.
In order to assess the outcome of this methodology, surveys on the subjects of interference, and diffraction of light were conductedduring three consecutive years. During the first year a textbooks based teaching without historical insight was imparted; later HPS based methods were introduced. The results show that students show more enthusiasm in lectures where the didactics uses HPS materials, and this methodology contributed to improve the students’ performance, increasing the percentage of correct answers in the exams.
Artificial vision assisted ground fine pointing system for experimental optical link for CubeSat communications
Authors: Medina I , Hernández-Gómez JJ , Miguel CR Torres-San , Couder-Castañeda C , Orozco-del-Castillo MG , Grageda-Arellano JI 
Published: June 2019

Abstract
Considering the continuous increase of demands in satellite communications, it is imperative to determine systems with higher bandwidths. Furthermore, miniaturization trends coming from the development of nanosatellites as CubeSat’s, constitute great restrictions to their design. Optical communications have the potential to lead with current data rates requirements. Nevertheless, the establishment of ground-LEO (Low Earth Orbit) optical links poses several challenges such as very strict and accurate tracking mechanisms, effects provoked due to the environmental conditions on the light beam as well as attenuation and Doppler effects. In this work, the precision of the tracking mechanisms is tackled by employing artificial vision as a proposal for a fine tracking system for an optical ground station to be able to locate a LEO CubeSat, so to proceed with data acquisition and tracking stages. The innovative and highly efficient algorithm herein developed for fine pointing is implemented in LabVIEW® as an example.
Clinoptilolite modified by calcium and hydroxyl ions for removal of fluoride from aqueous solution
Authors: Nuñez I Labastida , Perez M Velasco , Alvarez Dosamante K G 
Published: June 2019

Abstract
In Mexico naturally occurring fluoride contamination of groundwater is widespread. Adsorption with local and low-cost materials has been recently studied. In this research, clinoptilolite was modified with hydroxyl, calcium, and hydroxyl followed by calcium to compare their fluoride removal capacity. The sorption of natural and modified materials was investigated for the initial fluoride concentrations from 1.5 mg/L to 15 mg/L, isotherms for these adsorbents were investigated and techniques such as scanning electron microscopy (SEM) and X-ray diffraction (XDR) were used to characterize these adsorbents. It was found that removal fluoride was highest with calcium modified clinoptilolite from 60.2% with 1.5 mg F−/L to 43.0% with 15 mg F−/L. Sorption data for calcium modified clinoptilolite and hydroxyl and calcium modified clinoptilolite was found to fit Freundlich equations with equilibrium constants of 0.12 L/g and 0.021 L/g, respectively. SEM and XRD showed no significant changes of clinoptilolites after and before modification with calcium and sorption of fluoride, suggesting that interaction between adsorbent and adsorbate were only superficial. Modification of clinoptilolite with calcium enhanced its capacity for fluoride removal. This modification process was carried out using an economical and abundant mineral in central Mexico, which gives an additional advantage to the process.
Multifractal Analysis for the Overlapping Windows Method of a Time Series of Synthetic Earthquakes obtained with a Spring-Block Model
Authors: Aguilar-Molina A M , Perez-Oregon J , Muñoz-Diosdado A , Angulo-Brown F 
Published: June 2019

Abstract
We work with the model proposed by Olami, Feder and Christensen (OFC) to build time series with 10 000 000 data of synthetic earthquakes magnitudes, and conservation value β = 0.2. In this time series, we located the earthquakes with greater magnitude. We built 160 windows before and after these great earthquakes. The windows have 1024 data with an overlap of 896 points. For each windows, the values of the multifractality degree Δα and the parameter of symmetry were calculated. We follow the evolution of these parameters before and after the big earthquakes. The multifractal spectra have larger widths before than after the earthquake. The multifractal spectra of the 320 windows are left skewed, but the multifractal spectra of the time series before the earthquake are more biased towards the left than the multifractal spectra after the earthquake. Finally, we measured the curvature K around the maximum of the multifractal spectra, the K value is bigger before than after the earthquake. This suggests that there is apparently a process of preparation for the earthquake and that the dynamics after the earthquake is very different.
Characterization of thermographic images of skin cancer lesions using digital image processing
Authors: Benjumea E , Morales Y , Torres C , Vilardy J 
Published: June 2019

Abstract
Skin cancer is the type of cancer with the highest incidence in the world. The alterations of temperature in the skin are organic indicators of the presence of several types of skin cancer, mainly squamous cell carcinomas and melanomas. In this work, thermographic images of lesions of this type were analyzed in order to find indicators of the presence of this neoplasm that allow the future development of a detection algorithm. The digital processing used consists of identification of areas of interest, color segmentation, quantitative discrimination according to color tonality and analysis by histograms. The results showed that lesions with skin cancer have values in the red component above 100 under the RGB color space on a scale of 0 to 255. Also, when segmenting, by the k-means algorithm, a thermography containing a melanoma, the area that contains the lesion has a higher average value in the red component with respect to the other areas. Taking these results into account, a non-invasive tool for prediagnosing skin cancer can be developed that reduces unnecessary clinical procedures and simplifies the diagnosis.
Statistical study of the variable speed of an AACVD device implemented in the UTP
Authors: Hincapie J M , Castrillon E Y , Olarte W , Dorantes R J , Muñoz B Cruz 
Published: June 2019

Abstract
The spray assisted chemical vapor deposition (AACVD) technique is used to make thin film growth through the spraying of a precursor solution in the form of droplets, by means of a nozzle moving horizontally along the substrate. One of the most influential variables in the growth of the films is the speed with which the nozzle moves, since the deposition uniformity depends on this, which is directly related to the different physical properties of the coating. This paper briefly shows the electronic control built for the manipulation of this variable and a statistical study is presented that allowed to determine that the experimental speed presents oscillations less than 10% with respect to the programmed value. In addition, comparative transmittance spectra are shown where the reproducibility and repeatability of the coatings manufactured with the AACVD equipment built in the UTP is observed.
Multiple velocity estimation by maximum likelihood from MRI complex signals
Authors: Benitez-Read E E 
Published: June 2019

Abstract
The measurement of fluid velocity by encoding it in the phase of an MRI signal could allow the discrimination of the stationary spins signals from those of moving spins. This results in a wide variety of applications i.e. in medicine, in order to obtain more than angiograms, blood velocity images of veins, arteries and other vessels without having static tissue perturbing the signal of fluid in motion. This paper presents a novel theoretical and experimental method for the estimation of multiple velocities from MRI complex signals in the presence of stationary spins.
Hydrogen molecule adsorption on a Ti-doped graphene+ semi-fullerene surface.
Authors: Canales-Lizaola M , Arellano J S , Magaña L F 
Published: June 2019

Abstract
Density functional theory (DFT) was used to study the adsorption of a hydrogen molecule in the system formed by a graphene layer and a Ti doped semi-fullerene. We found that the semi-fullerene is bound to the graphene layer, with one of the hexagonal faces of the former being oriented into the latter, the adsorption energy is -14.97 eV. Afterwards, we found that the Ti atom is chemisorbed into the semi-fullerene, with an energy of -8.4 eV. Finally, we studied the interaction between the hydrogen molecule and the combined system, finding that the H2 is adsorbed by the system with an adsorption energy of -1.41 eV.
Arctic climate shifts drive rapid ecosystem responses across the West Greenland landscape
Authors: Saros Jasmine E , Anderson Nicholas John , Juggins Stephen , McGowan Suzanne , Yde Jacob C , Telling Jon , Bullard Joanna E , Yallop Marian L , Heathcote Adam J , Burpee Benjamin T , Fowler Rachel A , Barry Christopher D , Northington Robert M , Osburn Christopher L , Pla-Rabes Sergi , Mernild Sebastian H , Whiteford Erika J , Andrews M Grace , Kerby Jeffrey T , Post Eric 
Published: June 2019

Abstract
Prediction of high latitude response to climate change is hampered by poor understanding of the role of nonlinear changes in ecosystem forcing and response. While the effects of nonlinear climate change are often delayed or dampened by internal ecosystem dynamics, recent warming events in the Arctic have driven rapid environmental response, raising questions of how terrestrial and freshwater systems in this region may shift in response to abrupt climate change. We quantified environmental responses to recent abrupt climate change in West Greenland using long-term monitoring and paleoecological reconstructions. Using >40 years of weather data, we found that after 1994, mean June air temperatures shifted 2.2 °C higher and mean winter precipitation doubled from 21 to 40 mm; since 2006, mean July air temperatures shifted 1.1 °C higher. Nonlinear environmental responses occurred with or shortly after these abrupt climate shifts, including increasing ice sheet discharge, increasing dust, advancing plant phenology, and in lakes, earlier ice out and greater diversity of algal functional traits. Our analyses reveal rapid environmental responses to nonlinear climate shifts, underscoring the highly responsive nature of Arctic ecosystems to abrupt transitions.
Supply Chain Risk Management Analysis using the Development of Fuzzy Reasoning Methods and Analytical Network Process (ANP) at Wooden Toys Industries
Authors: Tanjung W N , Asti S S , Hidayat S , Ripmiatin E , Atikah S A , Khodijah R S 
Published: June 2019

Abstract
The supply chain is the relationship between material flows or services, money flow and information ranging from suppliers, producers, distributors, warehouses, retailers to customers. The smooth flow of material in the supply chain affected in the fulfillment of customer needs. If the problem occurs, it caused losses and risks. To minimize risks, it can be handled with Supply Chain Risk Management. This research was conducted in the supply chain in Wooden Toys Industries by identifying risks using the Fuzzy Reasoning method to calculate the amount of opportunity and impact that would arise if the risk occurred. To reduce the opportunity and impact of risk, a mitigation strategy is needed to consider and can be done using the Analytical Network Process method. Followed the results, the competitor’s moves have a large chance and risk. Thus, risk mitigation can be proposed is necessary to conduct market observations and identify competitors at (31.3%).
Measuring Influence from Safety Climate to Safety Behavior in Bus Rapid Transit Drivers
Authors: Safitri D M , Mediana A , Septiani W 
Published: June 2019

Abstract
Safety climate and safety behavior has an essential contribution to safety in all forms of the organizations. This research aimed to measure the impact of safety climate on safety behavior on bus rapid transit drivers in Jakarta. Bus rapid transit accident occurred inside and outside the bus lane. The incidence of the accident indicates that the risk is real. The measurement of the safety climate was using Nordic Safety Climate Questionnaire (NOSACQ-50). The NOSACQ-50 was adapted to fit the characteristics of transportation object. The questionnaire was distributed to 100 bus rapid transit drivers in Jakarta. Structural Equation Modelling – Partial Least Square (SEM-PLS) method was used to determine the influence safety climate to safety behavior among bus rapid transit drivers. The testing on the outer and inner model was conducted by bootstrapping and blindfolding process using Smart PLS software on the significance level of 0.05. The results of the study are that the workers’ safety commitment and safety communication, learning, and trust in co-workers’ safety competence had a positive and significant influence on safety behavior.
Workplace Ergonomic Risk Assessment Toward Small-Scale Household Business
Authors: Mufti Dessi , Ikhsan Aidil , Putri Tri Marta 
Published: June 2019

Abstract
The purpose of this research is to assess work risk caused by non-ergonomic of both facility layout and workplace at some Small Scale Medium Enterprises (SMEs) at nagari Batu Taba, sub-district IV Angkek, West Sumatera. The research samples are traditional food industrial and convection. The research participants are those who have been worked for more than ten years. Amongst the grievances experienced by the worker are tiredness and musculoskeletal disorders. This evaluation adopts the ergonomic facility layout and workplace through using Workplace Ergonomic Risk Assessment (WERA). The assessment result by implementing WERA shows that the worker does experience risk with final score 30 at medium level, as for the worker who cut the clothes pattern is at high level, 45. Task is not accepted and immediately changes. It means that some recommendations to improve the workplace are of vital importance. The ergonomic design introduced in this research has potential to reduce the risk at some small scale industrial at nagari Batu Taba, sub-district IV Angkek.
Analysis of Machine Maintenance Processes by using FMEA Method in the Sugar Industry
Authors: Soewardi Hartomo , Wulandari Siska Ari 
Published: June 2019

Abstract
Sugar is the daily basic need of human life. It is made from cane trees and manufactured using a milling machine in the early stages. This machine is operated 24 hours per day; consequently, it should be in a good condition and the company must be able to ensure the machine can run well by scheduling regular maintenance. This study aimed to investigate the potential failure of manufacturing process to provide some recommendations for improvement. Failure Mode and Effect Analysis (FMEA) method was applied to analyze the situation, and Logic Tree Analysis (LTA) was implemented to classify the types of improvement. This study found 13 failure modes, including a loose hammer tip, a broken end of the cutter, a non-balanced hammer rotation, a broken hammer handlebar, a broken wheel bearing, a loose switch, a loose split pen, a loose fastener bolt, an overload, a destroyed rubber seal, a broken turbine coupling, a broken screw-bolt, and a hollow roller. Meanwhile, the classification of improvement consisted of 3 categories namely safety problem (A), outage problem (B), and economic problem (C). Subsequently, the A category recommended setting up the machine in accordance with SOP while the B category recommended inspecting the machine routinely and preparing parts. In addition, the C category recommended performing accurate installation, lubrication, and cleaning.