Proyecto de una nave industrial con uso logístico de 5030 m2 en Colmenar Viejo

[ES] El TFM consiste en proyectar una nave industrial de carácter logístico definiendo su estructura constructiva que consiste en vigas y pilares de hormigón prefabricado y zapatas de cimentación de hormigón armado. El proyecto también incluye las instalaciones de protección contra incendios e instalación eléctrica.[EN] The Master Thesis consists of the determination of an industrial warehouse for logistic use defining its complete constructive structure made of precast concrete collumns and beams and reinforced concrete foundations. Additionally,the thesis includes the fire protection systems and electrical installations.[CA] El present treball fi de màster consistix a projectar una nau industrial de caràcter logístic ubicada en Colmenar Viejo (Madrid) . La seua estructura constructiva es definix amb bigues i pilars de formigó prefabricat i zapatas de fonamentació de formigó armat. La nau té una superfície total construïda de 5030 m2. El projecte també inclou les instal·lacions de protecció contra incendis i instal·lació elèctricaAyasli Boyacigil, B. (2021). Proyecto de una nave industrial con uso logístico de 5030 m2 en Colmenar Viejo. Universitat Politècnica de València. http://hdl.handle.net/10251/175617TFG

Formation scenarios and mass-radius relation for neutron stars

Neutron star crust, formed via accretion of matter from a companion in a low-mass X-ray binary (LMXB), has an equation of state (EOS) stiffer than that of catalyzed matter. At a given neutron star mass, M, the radius of a star with an accreted crust is therefore larger, by DR(M), than for usually considered star built of catalyzed matter. Using a compressible liquid drop model of nuclei, we calculate, within the one-component plasma approximation, the EOSs corresponding to different nuclear compositions of ashes of X-ray bursts in LMXB. These EOSs are then applied for studying the effect of different formation scenarios on the neutron-star mass-radius relation. Assuming the SLy EOS for neutron star's liquid core, derived by Douchin & Haensel (2001), we find that at M=1.4 M_sun the star with accreted crust has a radius more than 100 m larger that for the crust of catalyzed matter. Using smallness of the crust mass compared to M, we derive a formula that relates DR(M) to the difference in the crust EOS. This very precise formula gives also analytic dependence of DR on M and R of the reference star built of catalyzed matter. The formula is valid for any EOS of the liquid core. Rotation of neutron star makes DR(M) larger. We derive an approximate but very precise formula that gives difference in equatorial radii, DR_eq(M), as a function of stellar rotation frequency.Comment: 6 pages, 4 figures. Accepted for publication in Astronomy and Astrophysic

Large frequency drifts during Type I X-ray bursts

We study the spin-down of a neutron star atmosphere during the Type I X-ray burst in low mass X-ray binaries. Using polar cap acceleration models, we show that the resulting stellar ``wind'' torque on the burning shell due to the flowing charged particles (electrons, protons and ions) from the star's polar caps may change the shell's angular momentum during the burst. We conclude that the net change in the angular momentum of the star's atmosphere can account for rather large frequency drifts observed during Type I X-ray burst.Comment: 8 pages, more discussion adde

Ignition latitude and the shape of Type I X-ray bursts

The shape of the lightcurve during the rising phase of Type I X-ray bursts is determined by many factors including the ignition latitude, the accretion rate, and the rotation rate of the star. We develop a phenomenological model of the burst rise process and show that simple measures of the burst morphology can be robust diagnostics of ignition latitude and burning regime. We apply our results to the large sample of bursts from the Low Mass X-ray Binary 4U 1636-536, and find evidence for off-equatorial ignition for many of the bursts. We argue that such behaviour may be associated with the transition from hydrogen to helium ignition at accretion rates a few percent of Eddington. We show that this model can also explain variations in the detectability of burst oscillations, and discuss the implications for other burst sources.Comment: Some additions and clarifications, MNRAS accepte

Model atmospheres and X-ray spectra of iron-rich bursting neutron stars. II. Iron rich Comptonized Spectra

This paper presents the set of plane-parallel model atmosphere equations for a very hot neutron star (X-ray burst source). The model equations assume both hydrostatic and radiative equilibrium, and the equation of state of an ideal gas in local thermodynamic equilibrium (LTE). The equation of radiative transfer includes terms describing Compton scattering of photons on free electrons in fully relativistic thermal motion, for photon energies approaching m_e *c^2. Model equations take into account many bound-free and free-free energy-dependent opacities of hydrogen, helium, and the iron ions, and also a dozen bound-bound opacities for the highest ions of iron. We solve model equations by partial linearisation and the technique of variable Eddington factors. Large grid of H-He-Fe model atmospheres of X-ray burst sources has been computed for 10^7 < T_eff < 3*10^7 K, a wide range of surface gravity, and various iron abundances. We demonstrate that the spectra of X-ray bursters with iron present in the accreting matter differ significantly from pure H-He spectra (published in an earlier paper), and also from blackbody spectra. Comptonized spectra with significant iron abundance are generally closer to blackbody spectra than spectra of H-He atmospheres. The ratio of color to effective temperatures in our grid always remains in the range 1.2 < T_c/T_eff < 1.85. The present grid of model atmospheres and theoretical X-ray spectra will be used to determine the effective temperatures, radii and M/R ratios of bursting neutron stars from observational data.Comment: A&A in prin

Applied Plasma Research

Contains research objectives and reports on three research projects.National Science Foundation (Grant GK-10472)Lincoln Laboratory, M. I. T. (P. O. No. A-3393

Discovery of X-ray burst triplets in EXO 0748-676

[Abridged] Type-I X-ray bursts are thermonuclear flashes that take place on the surface of accreting neutron stars. The wait time between consecutive bursts is set by the time required to accumulate the fuel needed to trigger a new burst; this is at least one hour. Sometimes secondary bursts are observed, approximately 10 min after the main burst. These short wait-time bursts are not yet understood. We observed the low-mass X-ray binary and X-ray burster EXO 0748-676 with XMM-Newton for 158 h, during 7 uninterrupted observations lasting up to 30 h each. We detect 76 X-ray bursts. Most remarkably, 15 of these bursts occur in burst triplets, with wait times of 12 min between the three components of the triplet. We also detect 14 doublets with similar wait times between the two components of the doublet. The characteristics of the bursts indicate that possibly all bursts in this system are hydrogen-ignited, in contrast with most other frequent X-ray bursters in which bursts are helium-ignited, but consistent with the low mass accretion rate in EXO 0748-676. Possibly the hydrogen ignition is the determining factor for the occurrence of short wait-time bursts.Comment: 23 pages, 16 figures, accepted for publication in A&

Discovery of type-I X-ray bursts from the low-mass X-ray binary 4U 1708-40

We report the discovery of type-I X-ray bursts from the low-mass X-ray binary 4U 1708-40 during the 100 ks observation performed by BeppoSAX on 1999 August 15-16. Six X-ray bursts have been observed. The unabsorbed 2-10 keV fluxes of the bursts range from ~ (3-9)x10^(-10) erg cm^(-2)s^(-1). A correlation between peak flux and fluence of the bursts is found, in agreement with the behaviour observed in other similar sources. There is a trend of the burst flux to increase with the time interval from the previous burst. From the value of the persistent flux we infer a mass accretion rate Mdot~7x10^(-11) Msun/yr, that may correspond to the mixed hydrogen/helium burning regime triggered by thermally unstable hydrogen. We have also analysed a BeppoSAX observation performed on 2001 August 22 and previous RXTE observations of 4U 1708-40, where no bursts have been observed; we found persistent fluxes of more than a factor of 7 higher than the persistent flux observed during the BeppoSAX observation showing X-ray bursts.Comment: accepted for publication in MNRA

Measurement of neutron star parameters: a review of methods for low-mass X-ray binaries

Measurement of at least three independent parameters, for example, mass, radius and spin frequency, of a neutron star is probably the only way to understand the nature of its supranuclear core matter. Such a measurement is extremely difficult because of various systematic uncertainties. The lack of knowledge of several system parameter values gives rise to such systematics. Low-mass X-ray binaries, which contain neutron stars, provide a number of methods to constrain the stellar parameters. Joint application of these methods has a great potential to significantly reduce the systematic uncertainties, and hence to measure three independent neutron star parameters accurately. Here we review the methods based on (1) thermonuclear X-ray bursts; (2) accretion-powered millisecond-period pulsations; (3) kilohertz quasi-periodic oscillations; (4) broad relativistic iron lines; (5) quiescent emissions; and (6) binary orbital motions.Comment: 30 pages, 20 figures, 1 table, An Invited and Refereed Review, will be published in "Advances in Space Research