On global models for isolated rotating axisymmetric charged bodies; uniqueness of the exterior field

A relatively recent study by Mars and Senovilla provided us with a uniqueness result for the exterior vacuum gravitational field generated by an isolated distribution of matter in axial rotation in equilibrium in General Relativity. The generalisation to exterior electrovacuum gravitational fields, to include charged rotating objects, is presented here.Comment: LaTeX, 21 pages, uses iopart styl

Influence of general convective motions on the exterior of isolated rotating bodies in equilibrium

The problem of describing isolated rotating bodies in equilibrium in General Relativity has so far been treated under the assumption of the circularity condition in the interior of the body. For a fluid without energy flux, this condition implies that the fluid flow moves only along the angular direction, i.e. there is no convection. Using this simplification, some recent studies have provided us with uniqueness and existence results for asymptotically flat vacuum exterior fields given the interior sources. Here, the generalisation of the problem to include general sources is studied. It is proven that the convective motions have no direct influence on the exterior field, and hence, that the aforementioned results on uniqueness and existence of exterior fields apply equally in the general case.Comment: 8 pages, LaTex, uses iopart style files. To appear in Class. Quatum Gra

Tourist spaces and tourism policy in Spain and Portugal

Advances in Cultura, Tourism and Hospitality Research;10, 235-249This study analyses the relationship between the development of the tourism policy of Spain and Portugal and their effects on regional imbalances. Despite the proximity of the two countries and their specialisation in tourism, there are few comparative studies on tourism of the two Iberian countries. The study focuses on the two major phases of tourism policy: the period of mass tourism and post-Fordist stage. In the conclusions we refer the debate on the existence of a model of development based on tourism to the Latin countries of Southern Europe and we note the export process of the Spanish low-cost tourism model to other countries.Financiado por el Gobierno de España, Programa Fundamental de Investigación, Proyecto de I+D (CSO2012-30840) "Geografías de la crisis: análisis de los territorios urbanos y turísticos de las Islas Baleares, Costa del Sol y principales destinos del Caribe y América Central"

First and Second Order Perturbations of Hypersurfaces

In this paper we find the first and second order perturbations of the induced metric and the extrinsic curvature of a non-degenerate hypersurface $\Sigma$ in a spacetime $(M,g)$, when the metric $g$ is perturbed arbitrarily to second order and the hypersurface itself is allowed to change perturbatively (i.e. to move within spacetime) also to second order. The results are fully general and hold in arbitrary dimensions and signature. An application of these results for the perturbed matching theory between spacetimes is presented.Comment: 31 pages, no figures. To be published in Classical and Quantum Gravit

Lorentzian and signature changing branes

General hypersurface layers are considered in order to describe brane-worlds and shell cosmologies. No restriction is placed on the causal character of the hypersurface which may thus have internal changes of signature. Strengthening the results in our previous letter [1], we confirm that a good, regular and consistent description of signature change is achieved in these brane/shells scenarios, while keeping the hypersurface and the bulk completely regular. Our formalism allows for a unified description of the traditional timelike branes/shells together with the signature-changing, or pure null, ones. This allows for a detailed comparison of the results in both situations. An application to the case of hypersurface layers in static bulks is presented, leading to the general Robertson-Walker geometry on the layer --with a possible signature change. Explicit examples on anti de Sitter bulks are then studied. The permitted behaviours in different settings ($Z_{2}$-mirror branes, asymmetric shells, signature-changing branes) are analysed in detail. We show in particular that (i) in asymmetric shells there is an upper bound for the energy density, and (ii) that the energy density within the brane vanishes when approaching a change of signature. The description of a signature change as a `singularity' seen from within the brane is considered. We also find new relations between the fundamental constants in the brane/shell, its tension, and the cosmological and gravitational constants of the bulk, independently of the existence or not of a change of signature.Comment: 23 pages, 2 figure

Analisa Percobaan Terhadap Tingkat Cacat Malformbond (Golf Ball) Pada Proses Wire Bond Di Mesin Sinkawa (Utc-wb) Dengan Metode Anova Experiments Analysis of Malformbond Defect (Golf Ball) for Wire Bond Process in Sinkawa Machine (Utc –Wb) by Anova Method

PT.Infineon Technologies merupakan salah satu Perusahaaan manufacturing dengan hasil produksi berupa Integrated Circuit (IC). PT. Infineon Technologies Batam membagi proses produksinya menjadi beberapa departement, salah satunya yaitu departement perakitanyang terdiri dari beberapa proses pula, dan salah satunya yaitu proses wire bonding. Pada proses wire bonding diperiode minggu ke 40 - 52 ditemui cacat malformbond yang berasal dari mesin Sinkawa (UTC-WB) dengan wire size 50 µm. Dampak yang ditimbulkan dari cacat malformbond tersebut berpengaruh buruk dimana tingkat kualitas pada proses produksi sebesar 99,6 % yang diasumsikan bahwa 0,4 % adalah sebagai rejectpart yang di scrab. Cacat malformbond merupakan cacat yang sifatnya un-reworkable atau tidak dapat diperbaiki lagi. Cacat malformbond memberikan kontribusi sebesar 70% dari jumlah reject keseluruhan yang terjadi.Metode yang digunakan dalam penelitian ini adalah metode Analysis of Variance (ANOVA) yang digunakan untuk melihat perbandingan rata – rata beberapa kelompok. Tujuan analisa variansi adalah untuk menentukan apakah ada perbedaan antara beberapa perlakuan atau percobaan yang dilakukan hanyalah sebagai akibat dari variasi acak saja ataukah memang juga ada sumbangan dari variasi sitematik dalam jenis perlakuan untuk mengurangi jumlah cacat. Percobaan yang dilakukan adalah sebanyak 3 jenis, yaitu menaikkan paramater wire tensioner, penggunaan jig EFO untuk pemasangan electrode, dan menaikkan parameter wire tensioner serta menggunakan jig EFO.Hasil dari penelitian ini adalah memilih salah satu dari 3 percobaan yang dilakukan untuk menunjukkan tingkat pencapaian yield yang lebih baik dibanding yield sebelum percobaan. Percobaan yang terpilih adalah percobaan 3 yaitu menaikkan parameter wire tensioer serta menggunakan jig EFO electrode yang hasilnya adalah peninggkatan yield sebesar 1% menjadi 99.11% dari yield sebelum percobaan. Kata kunci: malformbond, yield, ANOVA,tingkat cacat PT.Infineon Technologies is one of the manufacturing firms with produce Integrated Circuit (IC). PT. Infineon Technologies Batam divide the production process into several departments, one of which is assembly department that consists of several process anyway, and one of them is wire bonding process. In the process of wire bonding period of weeks to 40-52 found defective malformbond coming from Sinkawa machibe (UTC-WB) with a wire size of 50 lm. The impact of the malformbond defects which adversely affect the level of quality in the production process 99,6% assumed that 0.4% is as reject part that in scrap. Malformbond defects are defects that are un-reworkable or cannot be repaired anymore. Malformbond defects accounted for 70% of the overall amount reject happened.The method used in this research is Analysis of Variance (ANOVA) was used to compare the average some groups. The objective of variance analysis is to determine whether there are differences between treatments or experiments carried out only as a result of random variation alone or is also a contribution of variations systematically in this type of treatment to reduce the number of defects. Experiments carried out is as much as three types, namely raising the wire tensioner parameters, use jig for mounting EFO electrode, and raise the tensioner and wire parameters using a jig EFO.The results of this research is to choose one of three experiments carried out to demonstrate the level of achievement of a better yield than the yield before the experiment. The experiments were selected were 3 trials of raising tensioer wire parameters using a jig EFO electrode and the result is increase yield from 1% to 99.11% of the yield before the experiment

ON the CONSERVATION of the VERTICAL ACTION in GALACTIC DISKS

We employ high-resolution N-body simulations of isolated spiral galaxy models, from low-amplitude, multi-armed galaxies to Milky Way-like disks, to estimate the vertical action of ensembles of stars in an axisymmetrical potential. In the multi-armed galaxy the low-amplitude arms represent tiny perturbations of the potential, hence the vertical action for a set of stars is conserved, although after several orbital periods of revolution the conservation degrades significantly. For a Milky Way-like galaxy with vigorous spiral activity and the formation of a bar, our results show that the potential is far from steady, implying that the action is not a constant of motion. Furthermore, because of the presence of high-amplitude arms and the bar, considerable in-plane and vertical heating occurs that forces stars to deviate from near-circular orbits, reducing the degree at which the actions are conserved for individual stars, in agreement with previous results, but also for ensembles of stars. If confirmed, this result has several implications, including the assertion that the thick disk of our Galaxy forms by radial migration of stars, under the assumption of the conservation of the action describing the vertical motion of stars. © 2016. The American Astronomical Society. All rights reserved

Cylindrically symmetric dust spacetime

We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has new surprising features. The universe is ``closed'' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is ``enclosed'' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable against some global {\it non-vacuum} perturbations.Comment: LaTeX, 6 pages, 1 figure. Uses epsfig package. Submitted to Classical and Quantum Gravit

Galactic Kinematics Towards the South Galactic Pole. First Results from the Yale-San Juan Southern Proper-Motion Program

The predictions from a Galactic Structure and Kinematic model code are compared to the color counts and absolute proper-motions derived from the Southern Proper-Motion survey covering more than 700 $\deg^2$ toward the South Galactic Pole in the range $9 < B_{\rm J} \le 19$. The theoretical assumptions and associated computational procedures, the geometry for the kinematic model, and the adopted parameters are presented in detail and compared to other Galactic Kinematic models of its kind. The data to which the model is compared consists of more than 30,000 randomly selected stars, and it is best fit by models with a solar peculiar motion of +5 km s$^{-1}$ in the V-component (pointing in the direction of Galactic rotation), a large LSR speed of 270 km s$^{-1}$, and a (disk) velocity ellipsoid that always points towards the Galactic center. The absolute proper-motions in the U-component indicate a solar peculiar motion of $11.0 \pm 1.5$ km s$^{-1}$, with no need for a local expansion or contraction term. The fainter absolute motions show an indication that the thick-disk must exhibit a rather steep velocity gradient of about -36 km s$^{-1}$ kpc$^{-1}$ with respect to the LSR. We are not able to set constraints on the overall rotation for the halo, nor on the thick-disk or halo velocity dispersions. Some substructure in the U & V proper-motions could be present in the brighter bins $10 < B_{\rm J} < 13$, and it might be indicative of (disk) moving groups.Comment: 24 double-column pages, 12 tables, AAS Latex macros v4.0, 19 B&W figures, 1 color figure. Accepted for publication on The Astronomical Journa