Solar-radiation-induced damage to optical properties of ZnO-type pigments Technical summary report, Jul. 1966 - Feb. 1968

Mechanisms of solar radiation damage to optical properties in zinc oxide pigments in visible and infrared region

The relation between the female somatotype and motor capacity.

Thesis (Ed.D.)--Boston University

Background and approach to a definition of smart buildings

There is no possibility of finding a single reference about domotics in the first half of the 20th century. The best known authors and those who have documented this discipline, set its origin in the 1970’s, when the x-10 technology began to be used, but it was not until 1988 when Larousse Encyclopedia decided to include the definition of "Smart Building". Furthermore, even nowadays, there is not a single definition widely accepted, and for that reason, many other expressions, namely "Intelligent Buildings" "Domotics" "Digital Home" or "Home Automation" have appeared to describe the automated buildings and homes. The lack of a clear definition for "Smart Buildings" causes difficulty not only in the development of a common international framework to develop research in this field, but it also causes insecurity in the potential user of these buildings. Thus, the main purpose of this paper is to propose a definition of the expression “Smart Buildings” that satisfactorily describes the meaning of this discipline. To achieve this aim, a thorough review of the origin of the term itself and the historical background before the emergence of the phenomenon of domotics was conducted, followed by a critical discussion of existing definitions of the term "Smart Buildings" and other similar terms. The extent of each definition has been analyzed, inaccuracies have been discarded and commonalities have been compared. Throughout the discussion, definitions that bring the term "Smart Buildings" near to disciplines such as computer science, robotics and also telecommunications have been found

Non-linear response of single-molecule magnets: field-tuned quantum-to-classical crossovers

Quantum nanomagnets can show a field dependence of the relaxation time very different from their classical counterparts, due to resonant tunneling via excited states (near the anisotropy barrier top). The relaxation time then shows minima at the resonant fields H_{n}=n D at which the levels at both sides of the barrier become degenerate (D is the anisotropy constant). We showed that in Mn12, near zero field, this yields a contribution to the nonlinear susceptibility that makes it qualitatively different from the classical curves [Phys. Rev. B 72, 224433 (2005)]. Here we extend the experimental study to finite dc fields showing how the bias can trigger the system to display those quantum nonlinear responses, near the resonant fields, while recovering an classical-like behaviour for fields between them. The analysis of the experiments is done with heuristic expressions derived from simple balance equations and calculations with a Pauli-type quantum master equation.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. B, brief report

Imaging the asymmetric dust shell around CI Cam with long baseline optical interferometry

We present the first high angular resolution observation of the B[e] star/X-ray transient object CI Cam, performed with the two-telescope Infrared Optical Telescope Array (IOTA), its upgraded three-telescope version (IOTA3T) and the Palomar Testbed Interferometer (PTI). Visibilities and closure phases were obtained using the IONIC-3 integrated optics beam combiner. CI Cam was observed in the near-infrared H and K spectral bands, wavelengths well suited to measure the size and study the geometry of the hot dust surrounding CI Cam. The analysis of the visibility data over an 8 year period from soon after the 1998 outburst to 2006 shows that the dust visibility has not changed over the years. The visibility data shows that CI Cam is elongated which confirms the disc-shape of the circumstellar environment and totally rules out the hypothesis of a spherical dust shell. Closure phase measurements show direct evidence of asymmetries in the circumstellar environment of CI Cam and we conclude that the dust surrounding CI Cam lies in an inhomogeneous disc seen at an angle. The near-infrared dust emission appears as an elliptical skewed Gaussian ring with a major axis a = 7.58 +/- 0.24 mas, an axis ratio r = 0.39 +/- 0.03 and a position angle theta = 35 +/- 2 deg.Comment: 9 pages, 5 figures, accepted MNRA

Interferometric science results on young stellar objects

Long-baseline interferometry at infrared wavelengths allows the innermost regions around young stars to be observed. These observations directly probe the location of the dust and gas in the disks. The characteristic sizes of these regions found are larger than previously thought. These results have motivated in part a new class of models of the inner disk structure, but the precise understanding of the origin of these low visibilities is still in debate. Mid-infrared observations probe disk emission over a larger range of scales revealing mineralogy gradients in the disk. Recent spectrally resolved observations allow the dust and gas to be studied separately showing that the Brackett gamma emission can find its origin either in a wind or in a magnetosphere and that there is probably no correlation between the location of the Brackett gamma emission and accretion. In a certain number of cases, the very high spatial resolution reveals very close companions and can determine their masses. Overall, these results provide essential information on the structure and the physical properties of close regions surrounding young stars especially where planet formation is suspected to occur.Comment: 18 pages, 6 figures, invited lecture at the VLTI school on "Astrometry and Imaging with the Very Large Telescope Interferometer", 2-13 June 2008, Keszthely, Hungary. v2: typos corrected; v3: reference adde

Solar radiation induced damage to optical properties of ZnO-type pigments Technical summary report, Jun. 27, 1966 - Mar. 27, 1967

Degradation model of solar radiation damage to optical properties of zinc oxide pigments used for spacecraft thermal control coating

Spatially Resolved Circumstellar Structure of Herbig Ae/Be Stars in the Near-Infrared

We have conducted the first systematic study of Herbig Ae/Be stars using the technique of long baseline stellar interferometry in the near-infrared. The principal result of this paper is that the IOTA interferometer resolves the source of infrared excess in 11 of the 15 systems surveyed. The visibility data for all the sources has been interpreted within the context of four simple models which represent a range of plausible representations for the brightness distribution of the source of excess emission: a Gaussian, a narrow uniform ring, a flat blackbody disk with a single temperature power law, and an infrared companion. We find that the characteristic sizes of the near-infrared emitting regions are larger than previously thought (0.5-5.9 AU, as given by the FWHM of the Gaussian intensity). A further major result of this paper is that the sizes measured, when combined with the observed spectral energy distributions, essentially rule out accretion disk models represented by blackbody disks with the canonical radial temperature law with exponent -3/4. We also find that, within the range observed in this study, none of the sources (except the new binary) shows varying visibilities as the orientation of the interferometer baseline changes. Taken as an ensemble, with no clear evidence in favor of axi-symmetric structure, the observations favor the interpretation that the circumstellar dust is distributed in spherical envelopes (the Gaussian model) or thin shells (the ring model).Comment: Accepted for publication by The Astrophysical Journa