Impulsive differential inclusions involving evolution operators in separable Banach spaces

We present some results on the existence of mild solutions and study the topological structures of the sets of solutions for the following first-order impulsive semilinear differential inclusions with initial and boundary conditions: where J=R+, 0 = t 0 < t 1 < … < t m <…, m∈N, lim k→∞ t k = ∞, A(t) is the infinitesimal generator of a family of evolution operators U(t, s) in a separable Banach space E and F is a set-valued mapping. The functions I k characterize the jumps of solutions at the impulse points t k , k = 1, ….The mapping L: PC b →E is a bounded linear operator. We also investigate the compactness of the set of solutions, some regularity properties of the operator solutions, and the absolute retract.Наведено деякi результати про iснування м’яких розв’язкiв та вивчено топологiчну будову множин розв’язкiв для наступних iмпульсних напiвлiнiйних диференцiальних включень першого порядку з початковими та граничними умовами: де J=IR+,0=t0<t1<...<tm<...;(m∈N),limk→∞tk=∞,A(t) — iнфiнiтезимальний генератор сiм’ї операторiв еволюцiї U(t,s) на сепарабельному банаховому просторi E та F — багатозначне вiдображення. Функцiї Ik характеризують стрибки розв’язкiв в точках iмпульсної дiї tk,k=1,... . Вiдображення L:PCb→E є обмеженим лiнiйним оператором. Також дослiджено компактнiсть множини розв’язкiв, деякi властивостi регулярностi операторних розв’язкiв та абсолютну ретрактнiсть

Search for a Solution of the Pioneer Anomaly

In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the first to explore the outer solar system and achieved stunning breakthroughs in deep-space exploration. But beginning in about 1980 an unmodeled force of \sim 8 \times 10^{-8} cm/s^2, directed approximately towards the Sun, appeared in the tracking data. It later was unambiguously verified as being in the data and not an artifact. The cause remains unknown (although radiant heat remains a likely origin). With time more and more effort has gone into understanding this anomaly (and also possibly related effects). We review the situation and describe ongoing programs to resolve the issue.Comment: 24 pages 8 figure

Simulación de un concentrador solar de disco parabólico para producción de potencia y enfriamiento

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este trabajo se presenta la modelación y simulación de un concentrador solar de disco parabólico para alimentar térmicamente a un sistema de refrigeración por absorción y a un motor Stirling, con diferente eficiencia, acoplado con un sistema de refrigeración por compresión. El enfriamiento producido por este sistema se utiliza para aire acondicionado de una vivienda. El estudio fue realizado mediante balances de energía y de masa, en cada componente de los sistemas de refrigeración y del sistema solar. La transferencia de calor por convección y por radiación también fueron considerados. Los resultados muestran que el colector solar alcanza eficiencia térmica de hasta 0.82 para relación de concentración de 100. El concentrador solar produce hasta 1.3 kW. En tanto que el sistema completo puede producir enfriamiento de 2.3 kW y 0.47 kW por el sistema de compresión y el de absorción respectivamente. La potencia de la bomba de la disolución es hasta 20 veces menor que la potencia requerida por el compresor del sistema de compresión.ABSTRACT: This paper presents the dish solar collector modeling and simulation for thermally driving an absorption refrigeration system and a Stirling engine, with different efficiency, coupled with a compression refrigeration system. The cooling produced by the system is used for home air conditioning. The study by means energy and mass balances, in each component of the cooling systems and the solar system was carried out. The Convection and radiation heat transfer also has been considered. The results show that the solar collector reaches thermal efficiency of up to 0.82 for a concentration ratio of 100. The solar concentrator produces up to 1.3 kW. While the complete system 2.3 kW and 0.47 kW of cooling by the compression and absorption system respectively can produce. The power of the solution pump is up to 20 times less than the power required by the compressor of the compression system.info:eu-repo/semantics/publishedVersio

The mur neutralisant as an active thermal system: Saint Gobain tests (1931) versus CFD simulation (2015)

[EN] At the same time as the initial development of air conditioning systems for indoor climate control in buildings were occurring in USA, Le Corbusier and Lyon made truly innovative proposals for different projects he was working on in Europe. These served to generate homogenous thermal environments and focused on the combined effect of his mur neutralisant and respiration exacte. The clearest example of their shortcomings is the City of Refuge in Paris (1930-33). Given the technological and economic mistrust towards these proposals, as it was impossible to execute these according to the original plan these were not pursued. CFD simulations carried out by our research team confirm that the mur neutralisant and respiration exacte for the City of Refuge in Paris would have functioned together if they had been executed following the original plans. The main aim of this paper is to confirm the validity of the mur neutralisant as an active thermal system for buildings. Firstly, the results of the tests carried out by the engineers of Saint Gobain are compared to the results of the CFD simulations. Based on the comparison of the results from the physical models tested in Saint Gobain laboratories and CFD energy model simulations, a possible calibration is proposed for CFD which might prompt the establishment of other operation hypotheses.Ramírez-Balas, C.; Sendra, J.; Suárez, R.; Fernández-Nieto, E.; Narbona-Reina, G. (2016). The mur neutralisant as an active thermal system: Saint Gobain tests (1931) versus CFD simulation (2015). En LE CORBUSIER. 50 AÑOS DESPUÉS. Editorial Universitat Politècnica de València. 1798-1819. https://doi.org/10.4995/LC2015.2015.899OCS1798181

Flux vacua in DBI type Einstein-Maxwell theory

We study compactification of extra dimensions in a theory of Dirac-Born-Infeld (DBI) type gravity. We investigate the solution for Minkowski spacetime with an $S^2$ extra space as well as that for de Sitter spacetime ($S^4$) with an $S^2$ extra space. They are derived by the effective potential method in the presence of the magnetic flux on the extra sphere. We also consider the higher dimensional generalization of the solutions. We find that, in a certain model, the radius of the extra space has a minimum value independent of the higher-dimensional Newton constant in weak-field limit.Comment: 13 pages, no figure. A reference added, typos fixe

Discovery and Cross-Section Measurement of Neutron-Rich Isotopes in the Element Range from Neodymium to Platinum at the FRS

With a new detector setup and the high-resolution performance of the fragment separator FRS at GSI we discovered 57 new isotopes in the atomic number range of 60$\leq Z \leq 78$: \nuc{159-161}{Nb}, \nuc{160-163}{Pm}, \nuc{163-166}Sm, \nuc{167-168}{Eu}, \nuc{167-171}{Gd}, \nuc{169-171}{Tb}, \nuc{171-174}{Dy}, \nuc{173-176}{Ho}, \nuc{176-178}{Er}, \nuc{178-181}{Tm}, \nuc{183-185}{Yb}, \nuc{187-188}{Lu}, \nuc{191}{Hf}, \nuc{193-194}{Ta}, \nuc{196-197}{W}, \nuc{199-200}{Re}, \nuc{201-203}{Os}, \nuc{204-205}{Ir} and \nuc{206-209}{Pt}. The new isotopes have been unambiguously identified in reactions with a $^{238}$U beam impinging on a Be target at 1 GeV/u. The isotopic production cross-section for the new isotopes have been measured and compared with predictions of different model calculations. In general, the ABRABLA and COFRA models agree better than a factor of two with the new data, whereas the semiempirical EPAX model deviates much more. Projectile fragmentation is the dominant reaction creating the new isotopes, whereas fission contributes significantly only up to about the element holmium.Comment: 9 pages, 4 figure

Peripheral organ equivalent dose estimation procedure in proton therapy

The aim of this work is to present a reproducible methodology for the evaluation of total equivalent doses in organs during proton therapy facilities. The methodology is based on measuring the dose equivalent in representative locations inside an anthropomorphic phantom where photon and neutron dosimeters were inserted. The Monte Carlo simulation was needed for obtaining neutron energy distribution inside the phantom. The methodology was implemented for a head irradiation case in the passive proton beam of iThemba Labs (South Africa). Thermoluminescent dosimeter (TLD)-600 and TLD-700 pairs were used as dosimeters inside the phantom and GEANT code for simulations. In addition, Bonner sphere spectrometry was performed inside the treatment room to obtain the neutron spectra, some relevant neutron dosimetric quantities per treatment Gy, and a percentual distribution of neutron fluence and ambient dose equivalent in four energy groups, at two locations. The neutron spectrum at one of those locations was also simulated so that a reasonable agreement between simulation and measurement allowed a validation of the simulation. Results showed that the total out-of-field dose equivalent inside the phantom ranged from 1.4 to 0.28 mSv/Gy, mainly due to the neutron contribution and with a small contribution from photons, 10% on average. The order of magnitude of the equivalent dose in organs was similar, displaying a slow reduction in values as the organ is farther from the target volume. These values were in agreement with those found by other authors in other passive beam facilities under similar irradiation and measurement conditions