804 research outputs found
Three-Body Dynamics and Self-Powering of an Electrodynamic Tether in a Plasmasphere
The dynamics of an electrodynamic tether in a three-body gravitational environment are investigated. In the classical two-body scenario the extraction of power is at the expense of orbital kinetic energy. As a result of power extraction, an electrodynamic tether satellite system loses altitude and deorbits. This concept has been proposed and well investigated in the past, for example for orbital debris mitigation and spent stages reentry. On the other hand, in the three-body scenario an electrodynamic tether can be placed in an equilibrium position fixed with respect to the two primary bodies without deorbiting, and at the same time generate power for onboard use. The appearance of new equilibrium positions in the perturbed three-body problem allow this to happen as the electrical power is extracted at the expenses of the plasma corotating with the primary body. Fundamental differences between the classical twobody dynamics and the new phenomena appearing in the circular restricted three-body problem perturbed by the electrodynamic force of the electrodynamic tether are shown in the paper. An interesting application of an electrodynamic tether placed in the Jupiter plasma torus is then considered, in which the electrodynamic tether generates useful electrical power of about 1 kW with a 20-km-long electrodynamic tether from the environmental plasma without losing orbital energy
Evaluation of the changes in working limits in an automobile assembly line using simulation
The aim of the work presented in this paper consists of the development of a decision-making support system, based on discrete-event simulation models, of an automobile assembly line which was implemented within an Arena simulation environment and focused at a very specific class of production lines with a four closed-loop network configuration. This layout system reflects one of the most common configurations of automobile assembly and preassembly lines formed by conveyors. The sum of the number of pallets on the intermediate buffers, remains constant, except for the fourth closed-loop, which depends on the four-door car ratio (x) implemented between the door disassembly and assembly stations of the car body. Some governing equations of the four closed-loops are not compatible with the capacities of several intermediate buffers for certain values of variable x. This incompatibility shows how the assembly line cannot operate in practice for x0,97 in a stationary regime, due to the starvation phenomenon or the failure of supply to the machines on the production line. We have evaluated the impact of the pallet numbers circulating on the first closed-loop on the performance of the production line, translated into the number of cars produced/hour, in order to improve the availability of the entire manufacturing system for any value of x. Until the present date, these facts have not been presented in specialized literature. © 2012 American Institute of Physics
A Non-Perturbative Chiral Approach for Meson-Meson Interactions
A non-perturbative method which combines constraints from chiral symmetry
breaking and coupled channel unitarity is used to describe meson-meson
interactions up to \sqrt{s}\lesssim 1.2 GeV, extending in this way the range of
applicability of the information contained in Chiral Perturbation Theory (\chi
PT), since this perturbative series is typically restricted to \sqrt{s}\lesssim
500 MeV. The approach uses the O(p^2) and O(p^4) \chiPT Lagrangians. The seven
free parameters resulting from the O(p^4) Lagrangian are fitted to the
experimental data. The approach makes use of the expansion of T^{-1} instead of
the amplitude itself as done in \chiPT. The former expansion is suggested by
analogy with the effective range approximation in Quantum Mechanics and it
appears to be very useful. The results, in fact, are in good agreement with a
vast amount of experimental analyses.Comment: 4 pages, 2 figures, LaTeX, Talk given at PANIC99, Uppsala (Sweden),
June 10-16, 199
On the nature of light scalar mesons from their large behavior
We show how to obtain information about the states of an effective field
theory in terms of the underlying fundamental theory. In particular we analyze
the spectroscopic nature of meson resonances from the meson-meson scattering
amplitudes of the QCD low energy effective theory, combined with the expansion
in the large number of colors. The vectors follow a qqbar behavior, whereas the
sigma, kappa and f_0(980) scalars disappear for large N_c, in support of a
qqqbarqbar-like nature. The a_0 shows a similar pattern, but the uncertainties
are large enough to accommodate both interpretations.Comment: 4 pages. Slightly shortened version to appear in Phys. Rev. Lett. Two
typos correcte
Identification of individualization techniques for criminal records in sanction lists
Using efficient searching techniques on sanctions list and press articles allows a better filtering on individuals and entities to establish a commercial relationship with, including those who are going to have access to confidential information belonging to the company, in order to minimize the risk of leakage or information mismanagement. That process of filtering on individuals or entities could be automated by using individualization algorithms, searching techniques based on string comparisons, artificial intelligence, and facial recognition. Diverse methods were examined to be applied on each mentioned technique in order to identify which ones are ideal to its application on individualization due to their characteristics, in order to obtain agile and reliable results; taking into account that different methods are complementary and not exclusive, and that their combination allows to minimize human interaction in the classification of information, avoiding analysis of data irrelevant for that particular search
Macro and microelements, lead, cadmium, functional compounds, antioxidant capacity in fresh, dry cocoa beans and cocoa paste
The cocoa bean and its by-products are widely consumed in the world, due to their mineral content, functional compounds and antioxidant capacity, which vary according to how its processed. Fresh dried cocoa beans (FDB), dry fermented beans (FB) and cocoa paste (CP) were investigated, 31 samples in each case. Phosphorus, sodium, calcium, magnesium, copper, iron, zinc, manganese, cadmium lead, total polyphenols, anthocyanins, antioxidant capacity (ABTS, DPPH) expressed in Trolox equivalents (TE) were determined. Principal component analysis (PCA) was used. The mineral analysis established that 12 samples influenced CP1 and CP2. There was more calcium in the M26 sample of FDB, with 3.14%; potassium in the FDB, in M13, with 2.44%. Zinc in the FDB, was found in greater quantity in M30, M22, M23 and M9; with 90.46 ± 0.19 ppm in M30. Twenty-five samples reached values ≤ 0.61 ± 0.01 ppm of cadmium. There was a higher lead content in the FDB, in the M20 sample with 3.44 ± 0.05 ppm. The M10 sample, from FDB, presented the highest antioxidant capacity, with values of 591.50 ± 3.76 (ABTS) and 513.68 ± 0.84 (DPPH) μM TE/g.The cocoa bean and its by-products are widely consumed in the world, due to their mineral content, functional compounds and antioxidant capacity, which vary according to how its processed. Fresh dried cocoa beans (FDB), dry fermented beans (FB) and cocoa paste (CP) were investigated, 31 samples in each case. Phosphorus, sodium, calcium, magnesium, copper, iron, zinc, manganese, cadmium lead, total polyphenols, anthocyanins, antioxidant capacity (ABTS, DPPH) expressed in Trolox equivalents (TE) were determined. Principal component analysis (PCA) was used. The mineral analysis established that 12 samples influenced CP1 and CP2. There was more calcium in the M26 sample of FDB, with 3.14%; potassium in the FDB, in M13, with 2.44%. Zinc in the FDB, was found in greater quantity in M30, M22, M23 and M9; with 90.46 ± 0.19 ppm in M30. Twenty-five samples reached values ≤ 0.61 ± 0.01 ppm of cadmium. There was a higher lead content in the FDB, in the M20 sample with 3.44 ± 0.05 ppm. The M10 sample, from FDB, presented the highest antioxidant capacity, with values of 591.50 ± 3.76 (ABTS) and 513.68 ± 0.84 (DPPH) μM TE/g
- …