arXiv subjects

P. A. Ospina-Henao

Publications and source records attributed to P. A. Ospina-Henao.

5 recordsLinked to original sources

arXiv2019

Radiation Dose Charts for Long Geodetic and Polar Flights with CARI-7A

We have calculated by using CARI-7A the effective and ambient radiation doses absorbed by a reference human phantom inside aircrafts with cruise speed, and averaged ascent/descent rates as presented by real airplanes such as: Airbus 380, Boeing 777, 787, Hercules C-130 and Twin Otter DHC-6, in a sample of flight aerial routes in a range of flight levels. In the sample, fifteen routes are between the longest non-stop flight around the world, where four flights pass over the Arctic and we have considered one air route involving the Antarctica with two additional special cases. The Earth curvature based on model WGS84 was taken into account for every point in each route by using the INVERSE3D software. Then we constructed radiation dose charts according to the ICRP-103 conditions by using the radiometric results coming from the CARI-7A simulations. These charts present the effective absorbed radiation dose as a function of flight level and flight time in a year of normal operations of the crew as recommended by the FAA. We have also characterized geographically and kinematically the cosmic effective radiation absorption rates at Earth's atmosphere in terms of the structure and order of polynomials in the altitude. From the flight with the leading rate of irradiation we found a thumb rule to estimate the effective absorbed radiation dose and the ambient equivalent dose that gives a superior threshold for any flight of the sample and perhaps on Earth, valid in altitude interval [20000, 50000] ft.

physics.med-ph↗

arXiv2017

Dynamic, modeling and simulation of an underactuated system

In this paper, is used the Lagrangian classical mechanics for modeling the dynamics of an underactuated system, specifically a rotary inverted pendulum that will have two equations of motion. A basic design of the system is proposed in SOLIDWORKS 3D CAD software, which based on the material and dimensions of the model provides some physical variables necessary for modeling. In order to verify the results obtained, a comparison the CAD model simulated in the environment SimMechanics of MATLAB software with the mathematical model who was consisting of Euler Lagrange's equations implemented in Simulink MATLAB, solved with the ODE23tb method, included in the MATLAB libraries for the solution of systems of equations of the type and order obtained. This article also has a topological analysis of pendulum trajectories through a phase space diagram, which allows the identification of stable and unstable regions of the system.

cs.RO↗

arXiv2017

Dynamic analysis and control PID path of a model type gantry crane

This paper presents an alternate form for the dynamic modelling of a mechanical system that simulates in real life a gantry crane type, using Euler's classical mechanics and Lagrange formalism, which allows find the equations of motion that our model describe. Moreover, it has a basic model design system using the SolidWorks software, based on the material and dimensions of the model provides some physical variables necessary for modelling. In order to verify the theoretical results obtained, a contrast was made between solutions obtained by simulation in SimMechanics-Matlab and Euler-Lagrange equations system, has been solved through Matlab libraries for solving equation's systems of the type and order obtained. The force is determined, but not as exerted by the spring, as this will be the control variable. The objective to bring the mass of the pendulum from one point to another with a specified distance without the oscillation from it, so that, the answer is overdamped. This article includes an analysis of PID control in which the equations of motion of Euler-Lagrange are rewritten in the state space, once there, they were implemented in Simulink to get the natural response of the system to a step input in F and then draw the desired trajectories.

nlin.CD↗

arXiv2017

Dynamic Modeling and Simulation of a Rotational Inverted Pendulum

This paper presents an alternative way to the dynamic modeling of a rotational inverted pendulum using the classic mechanics known as Euler-Lagrange allows to find motion equations that describe our model. It also has a design of the basic model of the system in SolidWorks software, which based on the material and dimensions of the model provides some physical variables necessary for modeling. In order to verify the theoretical results, It was made a contrast between the solutions obtained by simulation SimMechanics-Matlab and the system of equations Euler-Lagrange, solved through ODE23tb method included in Matlab bookstores for solving equations systems of the type and order obtained. This article comprises a pendulum trajectory analysis by a phase space diagram that allows the identification of stable and unstable regions of the system.

nlin.CD↗

arXiv2010

Charged Annular Disks and Reissner-Nordström Type Black Holes from Extremal Dust

We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disk-like configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential and an auxiliary function,which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin Inversion Method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordström black hole can be embedded into the center of the disks by adding a boundary term in the inversion.

gr-qc↗