cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14325890.v1
title: An introduction to strange stars

description: Abstract The description of the densest neutron stars found in Nature depends on the understanding of the physical concepts present in General Relativity and in the theory of strong interactions – the Quantum Chromodynamics. In this work we review the essential concepts to describe strange stars, constituted by quarks up, down and strange, which is one of the alternatives for the composition of ultradense neutron stars. We will review the Bodmer-Witten-Terazawa hypothesis, which states that the strange matter is absolutely stable in relation to the ordinary nuclear matter, and discuss the basic properties that characterize strange stars. Our goal is to present the necessary concepts to understand this important theme of Astroparticles.
DOI: 10.6084/m9.figshare.14325893
title: An alternative mobility & transportation that uses gravity for the colonization of the Moon

description: It is well known that hypothetical tunnels net within the Earth is usually considered as an illustration in a gravitation course for undergraduate students. In this context, an uniform mass distribution is usually considered and, consequently, a vehicle inside the tunnel oscillates in a simple harmonic motion (SHM). In this work, we investigate this problem and we argue that, instead to illustrate this problem using Earth, it is better to consider the Moon. In order to support this proposition, we present a twofold argumentation: first, we show that there is a quite discrepancy between the results obtained from Earth uniform mass distribution model with those obtained considering realistic Earth models (PREM model), whose mass is nonuniformly distributed; second, when the Moon is considered, we show that there is not a discrepancy between the results computed from uniform mass distribution model with those computed from nonuniform mass distribution. Indeed, we revealed that a vehicle inside the tunnel within Moon oscillates approximately in a SHM.
DOI: 10.6084/m9.figshare.14325893.v1
title: An alternative mobility & transportation that uses gravity for the colonization of the Moon

description: It is well known that hypothetical tunnels net within the Earth is usually considered as an illustration in a gravitation course for undergraduate students. In this context, an uniform mass distribution is usually considered and, consequently, a vehicle inside the tunnel oscillates in a simple harmonic motion (SHM). In this work, we investigate this problem and we argue that, instead to illustrate this problem using Earth, it is better to consider the Moon. In order to support this proposition, we present a twofold argumentation: first, we show that there is a quite discrepancy between the results obtained from Earth uniform mass distribution model with those obtained considering realistic Earth models (PREM model), whose mass is nonuniformly distributed; second, when the Moon is considered, we show that there is not a discrepancy between the results computed from uniform mass distribution model with those computed from nonuniform mass distribution. Indeed, we revealed that a vehicle inside the tunnel within Moon oscillates approximately in a SHM.
DOI: 10.6084/m9.figshare.14325894.v1
title: Asymptotic boundary conditions in harmonic oscillators and applications

description: In this paper we present an analysis of the asymptotic behavior of damped and forced harmonic oscillators considering the (x2 , x . 2) representation , we find that from the analysis of the asymptotic behavior of boundary conditions , taking as an example the case of damped and forced harmonic oscillators, which its possible infer the dynamical behavior in this region for more complex systems, such as the nonlinear oscillator described in section 5.Some implications of the asymptotic solution for this system are discussed at the end of this section. However, a more detailed analysis of the analytical behavior of this system would be beyond the scope of this paper.
DOI: 10.6084/m9.figshare.14325894
title: Asymptotic boundary conditions in harmonic oscillators and applications

description: In this paper we present an analysis of the asymptotic behavior of damped and forced harmonic oscillators considering the (x2 , x . 2) representation , we find that from the analysis of the asymptotic behavior of boundary conditions , taking as an example the case of damped and forced harmonic oscillators, which its possible infer the dynamical behavior in this region for more complex systems, such as the nonlinear oscillator described in section 5.Some implications of the asymptotic solution for this system are discussed at the end of this section. However, a more detailed analysis of the analytical behavior of this system would be beyond the scope of this paper.
DOI: 10.6084/m9.figshare.14325899
title: The physics of stochastic processes applied to binary options in financial markets

description: Abstract The analogy between the problem of a player who bets money iteratively in a game of chance and a random walker in one dimension with an absorbing boundary is well known. These and other connections between finance and physics motivated the emergence of the field of econophysics in the 1990s. Since the subject matter is still not well known at the level of undergraduate physics programs, here we first review some basic concepts, such as martingales, financial derivatives and stock options. Our objectives are the following: (i) to explain how binary options work; (ii) to simulate stochastically the behavior of the balance sheet curve for different hit rates; (iii) to run tests of the success rates for the stochastic oscillator indicator in financial time series of historical data. This indicator is widely used by binary option traders, so it is an ideal illustrative example. Our results show that it is difficult to obtain consistent profits, even using strategies based on martingales or “Soros” leveraging to recover previous losses. The empirical characterization of this difficulty may help to make clearer the unpredictability and high degree of complexity of the behavior seen in financial markets.
DOI: 10.6084/m9.figshare.14325899.v1
title: The physics of stochastic processes applied to binary options in financial markets

description: Abstract The analogy between the problem of a player who bets money iteratively in a game of chance and a random walker in one dimension with an absorbing boundary is well known. These and other connections between finance and physics motivated the emergence of the field of econophysics in the 1990s. Since the subject matter is still not well known at the level of undergraduate physics programs, here we first review some basic concepts, such as martingales, financial derivatives and stock options. Our objectives are the following: (i) to explain how binary options work; (ii) to simulate stochastically the behavior of the balance sheet curve for different hit rates; (iii) to run tests of the success rates for the stochastic oscillator indicator in financial time series of historical data. This indicator is widely used by binary option traders, so it is an ideal illustrative example. Our results show that it is difficult to obtain consistent profits, even using strategies based on martingales or “Soros” leveraging to recover previous losses. The empirical characterization of this difficulty may help to make clearer the unpredictability and high degree of complexity of the behavior seen in financial markets.
DOI: 10.6084/m9.figshare.14325900.v1
title: Solving Differential Equations Using Adomian Decomposition Method

description: Abstract Searching for solution of a differential equation can be one of the main tasks of a physicist. In this sense, the greater the number of known solution methods, the wider the variety of problems that can be analyzed and understood. Among the differential equations, the non-linear equations are the ones with the greatest resolution complexity and are routinely present in the description of natural phenomena. In this perspective, this work presents an introduction to the Adomian Decomposition Method, which is an analytical method vastly used to address non-linear differential equations. To exemplify the applicability of the Adomian method, some linear and non-linear examples are treated, namely: free fall of a particle under air resistance, simple gravity pendulum and a one-dimensional non-uniform transport wave equation.
DOI: 10.6084/m9.figshare.14325900
title: Solving Differential Equations Using Adomian Decomposition Method

description: Abstract Searching for solution of a differential equation can be one of the main tasks of a physicist. In this sense, the greater the number of known solution methods, the wider the variety of problems that can be analyzed and understood. Among the differential equations, the non-linear equations are the ones with the greatest resolution complexity and are routinely present in the description of natural phenomena. In this perspective, this work presents an introduction to the Adomian Decomposition Method, which is an analytical method vastly used to address non-linear differential equations. To exemplify the applicability of the Adomian method, some linear and non-linear examples are treated, namely: free fall of a particle under air resistance, simple gravity pendulum and a one-dimensional non-uniform transport wave equation.
DOI: 10.6084/m9.figshare.14325902
title: Surviving the Zombie Apocalypse: A Population Dynamics Based Approach

description: Abstract Living-dead creatures are recurrent in various folk myths and recently became an icon of popular culture. The “zombie-ism” is usually caused by an infectious-like disease that has no cure and ultimately inflicts most of the human population, leading to a Zombie Apocalypse. In this work, we propose an epidemiological model for a zombie outbreak. By introducing an infection parameter, we show that human survival is possible in certain scenarios. Furthermore, our model allows for three distinct dynamical regimes, only one of which accounts for the full blown Zombie Apocalypse. Our results are obtained both for a fully connected time continuous model and for a stochastic individual based approach.
DOI: 10.6084/m9.figshare.14325902.v1
title: Surviving the Zombie Apocalypse: A Population Dynamics Based Approach

description: Abstract Living-dead creatures are recurrent in various folk myths and recently became an icon of popular culture. The “zombie-ism” is usually caused by an infectious-like disease that has no cure and ultimately inflicts most of the human population, leading to a Zombie Apocalypse. In this work, we propose an epidemiological model for a zombie outbreak. By introducing an infection parameter, we show that human survival is possible in certain scenarios. Furthermore, our model allows for three distinct dynamical regimes, only one of which accounts for the full blown Zombie Apocalypse. Our results are obtained both for a fully connected time continuous model and for a stochastic individual based approach.
DOI: 10.6084/m9.figshare.14325852.v1
title: Nurses' role in the non-pharmacological pain treatment in cancer patients

description: ABSTRACT BACKGROUND AND OBJECTIVES: Non-pharmacological therapy is important and complements the pharmacological treatment to relieve the pain and anxiety in many patients, and it is also classified as complementary and integrative therapy. The objective of this study was to describe the nurses’ role in non-pharmacological pain management in cancer patients. CONTENTS: Integrative literature review. Scientific publications indexed in the Medline, Integrated Building Environmental Communications System, LILACS and Nursing databases, accessed through the Virtual Health Library in October 2016, were evaluated. Following the inclusion criteria, seven studies were selected, published between 2006 and 2016. Data were subjected to content analysis. Based on this analysis, the articles were described in three categories: 1) the perception of nurses; 2) the perception of the patient, and 3) nursing actions. CONCLUSION: It was evident the fundamental and important role of the nursing staff in the non-pharmacological pain management in cancer patients. Both patients and family members should actively participate in the treatment. It is recommended the development of reliable and effective communication links, in addition to the implementation of educational actions involving the triad patient-family-team.
DOI: 10.6084/m9.figshare.14325598.v1
title: Tide assessment for the continental shelf situated in the southwestern Atlantic between the latitudes 19.8ºS and 21.2ºS

description: Abstract The astronomical tide was numerically simulated by the MOHID model for the South-Central Region of Espírito Santo State (Brazil), between latitudes 19.8ºS and 21.2ºS. The grid nesting technique was used to transpose the boundary conditions from the larger domain to a more refined local domain (spatial resolution around 450 m), with tidal harmonics provided by the TPXO tide inverse model as boundary conditions for the larger domain. Results from the numerical model were compared with both the pre-existing tide harmonics and the harmonics calculated from measured data. From the maps of phase, amplitude, tidal ellipses and residual currents the main tidal kinematic characteristics in the study area were described. On the continental shelf, the results showed that the physiography and bathymetry of the region play an important role in the distribution of tidal co-phases, co-amplitudes, ellipses and residual currents. The MOHID model was able to reproduce satisfactorily the astronomical tide and thus can be used to study the behaviour of the tidal propagation in continental shelf areas.
DOI: 10.6084/m9.figshare.14325903
title: A zero cost methodology for the measurement of the rolling resistance in UAVs

description: Abstract Despite the fact that measurements of the rolling friction coefficient are important in several areas, the subject in general is not adequately addressed in high school or college. This situation deprives the student of the knowledge of the experimental resources used to measure the friction coefficient, in addition to compromising the understanding of the phenomenon. In addition, certain pairs of materials of interest to engineering are simply not found in the literature, as in the case of tires used in unmanned aerial vehicles (UAVs). In an attempt to fill both gaps, the present work presents a methodology for determining the rolling friction coefficient in UAVs. The method used is extremely simple, in terms of its implementation and of the theory used, but it is still interesting from a didactic point of view and due to the fact that its cost is practically zero, using only an inclined plane and measures of the distance covered by the UAV. The results show friction coefficient values depending on the vehicle's weight. The values obtained are discussed and suggestions for the future improvement of the experiment are presented.
DOI: 10.6084/m9.figshare.14325393.v1
title: Modeling Particles Elements in Damaged Reinforced Concrete Structures

description: Abstract In this paper, we introduce a finite element mesoscale modeling of damaged concrete structures, based on nodal positions. The mesoscale modeling consists of particle and fiber finite elements embedded in matrix finite elements. While the matrix elements represent the cement matrix, particle elements are used to simulate the coarse aggregates and fiber elements are used for reinforcement rebars. The embedded theory is used to immerse the reinforcement (both particle and fiber elements) without increasing the total number of degrees of freedom. This strategy does not require nodal coincidence, allowing randomly distribute the coarse aggregates. The materials nonlinear behavior is considered by a scalar damage model for the cement matrix and coarse aggregates, and one-dimensional elastoplastic model is used for the steel rebars. Four examples are presented, with good correlation between numerical and experimental results. It is shown that structures simulated with particulate elements could endure higher loads for the same displacement, although the maximum force is obtained in models without inclusion of particle elements.
DOI: 10.6084/m9.figshare.14325905
title: Some concepts in the teaching of Cosmology that almost always create confusion

description: Abstract The teaching of the evolution of the Universe is one of the most complex subjects that can be addressed in the classroom. The involved concepts are frequently very far away of any intuition, and are difficult to expose and discuss. We point out in this communication some of these basic concepts related to the Big Bang, analyzing their scientific content and the most common mistakes made by students and their teachers with the intention of improving the teaching of this branch of Science. The danger of didactical analogies commonly used are pointed out for each case.
DOI: 10.6084/m9.figshare.14325905.v1
title: Some concepts in the teaching of Cosmology that almost always create confusion

description: Abstract The teaching of the evolution of the Universe is one of the most complex subjects that can be addressed in the classroom. The involved concepts are frequently very far away of any intuition, and are difficult to expose and discuss. We point out in this communication some of these basic concepts related to the Big Bang, analyzing their scientific content and the most common mistakes made by students and their teachers with the intention of improving the teaching of this branch of Science. The danger of didactical analogies commonly used are pointed out for each case.
DOI: 10.6084/m9.figshare.14325908
title: Mechanical refraction in action

description: Abstract We study the analog of Snell's law for particles moving across the interface of two regions with two different potential energies, from two different points of view. First, a simple demonstration involving marbles and a potential step is shown. Then, from a theoretical point of view, this law describing mechanical refraction is derived from the Maupertuis and Jacobi variational principles, in close analogy with the well known derivation of Snell's law for refraction from Fermat's least time principle. Finally, the relativistic version of mechanical refraction is obtained by the Maupertuis principle, by trading the Newtonian dispersion relation with the relativistic one. The pedagogical significance of this treatment is discussed.
DOI: 10.6084/m9.figshare.14325388.v1
title: Dynamic model of a logistic train with different steering systems and tire models

description: Abstract Logistic train is one of the recent solutions applied in the intralogistics. It bases on the concept of the “milk-run” delivery method. The main problem in the implementation of intralogistics trains is the possibility to determine whether the train is able to pass the given path without a colliding with surrounding objects. Dynamic model presented in this paper was performed for the three most common steering systems for the trolleys: double Ackermann steering system and two drawbar systems: conventional and virtual clutch. The dynamic model was developed following Lagrange’s theorem including the possibility of lateral slip. The system of differential equations was numerically solved. In order to calculate the lateral friction forces we used three different tire models: simplified, sigmoidal and Pacejka Magic formula. The results obtained for different tire models and steering systems are presented in the form of animations presenting train run in various conditions. The analyses have shown that the use of simplified tire models is justified under certain conditions.
DOI: 10.6084/m9.figshare.14325908.v1
title: Mechanical refraction in action

description: Abstract We study the analog of Snell's law for particles moving across the interface of two regions with two different potential energies, from two different points of view. First, a simple demonstration involving marbles and a potential step is shown. Then, from a theoretical point of view, this law describing mechanical refraction is derived from the Maupertuis and Jacobi variational principles, in close analogy with the well known derivation of Snell's law for refraction from Fermat's least time principle. Finally, the relativistic version of mechanical refraction is obtained by the Maupertuis principle, by trading the Newtonian dispersion relation with the relativistic one. The pedagogical significance of this treatment is discussed.
DOI: 10.6084/m9.figshare.14325376.v1
title: Buckling of cracked cones subjected to axial compression

description: Abstract The influence of crack geometry on the buckling load of axially compressed mild steel cones was presented in this paper. The following geometrical parameter was used: bottom radius-to-top radius ratio, r2/r1=2.0; top radius-to-thickness ratio, r1/t=25; axial length-to-bottom radius ratio, L/r2=2.24; nominal shell thickness, t=1mm; cone angle, β=12.6°. The local buckling phenomenon was investigated through a series of numerical computations (50 ≤ r1/t ≤ 2000). Numerical results show that crack geometry (i.e., length and orientation) influences the buckling strength of the cones differently. For instance, as the crack length increases, the loading capacity of cones drops; cones with a circumferential crack (0°) display the most severe drop. As the crack orientation increases (from 0° to 90°) the buckling strength of the cracked cones with crack length greater than 1 increases. Whereas, for cracked cones with crack length less than 1, increasing the crack orientation has little or no effect on the buckling strength. Hence, it can be said that crack orientation has a secondary effect on the buckling of cracked conical shells.
DOI: 10.6084/m9.figshare.14325372.v1
title: Collapse of I-section tapered beam-columns in medium-span steel frames: Finite element model validation and parameters influence evaluation

description: Abstract Tapered steel beams and columns have been increasingly used as primary load carrying members. The determination of their accurate ultimate capacity can only be achieved employing advanced numerical methods such as the finite element method (FEM). This paper presents a systematic study on the influence of FE model parameters on the ultimate load of I-section tapered beam-columns typically used in medium-span steel frames. It aims the determination of optimal FE mesh size and sub-step number to be used during the arc-length scheme for the performance of an accurate, robust and efficient inelastic post-buckling parametric analysis (PA) as well as the evaluation of the parameters influence. Once validated the FE model, using hexahedral 8-node finite elements, FE edge sizes of 20, 25 and 30 mm and 10 sub-steps have been selected for use in the future PA. Several FE analyses were also carried out to evaluate how it is and quantify the influence of each of the parameters, leading to empirical equations with errors in the range of -35% to 35% for equations without crossed terms and -23% to 23% with first-order crossed terms.