1,673 research outputs found

    Balloon-borne package temperature controller

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    Simple, inexpensive, lightweight enclosure traps upward long wave radiation of earth while reflecting harsh solar radiation in upper atmosphere. It warms enclosed instruments in cold regions and protects them from overheating during the day. Device can be attached to balloon system without any changes in experimental design

    Apparatus for controlling the temperature of balloon-borne equipment

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    A novel apparatus for controlling the temperature of balloon-borne equipment is disclosed, the apparatus serving to utilize the radiant energy emitted by the earth and its atmosphere so as to control the temperature of equipment. The apparatus comprises a housing to be carried aloft by a balloon and defining an enclosure for an instrumentation package. The enclosure includes an upper shield portion as well as a bottom window portion at the base, the bottom window facing the earth below during flight. The upper shield portion is constructed of a material such as aluminized Mylar, which serves to reflect direct sunlight

    Triphilic ionic-liquid mixtures: fluorinated and non-fluorinated aprotic ionic-liquid mixtures

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    We present here the possibility of forming triphilic mixtures from alkyl- and fluoroalkylimidazolium ionic liquids, thus, macroscopically homogeneous mixtures for which instead of the often observed two domainspolar and nonpolarthree stable microphases are present: polar, lipophilic, and fluorous ones. The fluorinated side chains of the cations indeed self-associate and form domains that are segregated from those of the polar and alkyl domains. To enable miscibility, despite the generally preferred macroscopic separation between fluorous and alkyl moieties, the importance of strong hydrogen bonding is shown. As the long-range structure in the alkyl and fluoroalkyl domains is dependent on the composition of the liquid, we propose that the heterogeneous, triphilic structure can be easily tuned by the molar ratio of the components. We believe that further development may allow the design of switchable, smart liquids that change their properties in a predictable way according to their composition or even their environment

    Drug user dynamics: a compartmental model of drug users for scenario analyses

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    A six-typology compartment model of trends in the use of illicit drugs in Italy is developed to evaluate policies and interventions through scenario analyses. Inside the big compartments of just-cannabis users and multiple drug users, three subpopulations are taken into account: the occasional, regular and intensive user. Moreover, compartments for health care, assisted persons together with a constant source (susceptible) are added; removed people (i.e. those who leave drugs for any reason) are put in a compartment which does not participate in the dynamics. Flows from the susceptible reservoir among the drug-user compartments and to the removed or the health care compartments are studied in a deterministic linear ODE framework, where parameters are estimated using Italian data. This system shows an evolution towards a steady state, the speed of convergence being dependent on parameters in a fairly visible way. This model represents a theoretical development in drug policy analysis, as it shows the relevance of flux parameters, which are in principle subject to modifications due to institutional efforts, together with a quantitative evaluation of their role in the evolution of the whole system

    An invariant analytic orthonormalization procedure with applications

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    We apply the orthonormalization procedure previously introduced by two of us and adopted in connection with coherent states to Gabor frames and other examples. For instance, for Gabor frames we show how to construct g(x)∈L2(R)g(x)\in L^2(\Bbb{R}) in such a way the functions gn‾(x)=eian1xg(x+an2)g_{\underline n}(x)=e^{ian_1x}g(x+an_2), n‾∈Z2\underline n\in\Bbb{Z}^2 and aa some positive real number, are mutually orthogonal. We discuss in some details the role of the lattice naturally associated to the procedure in this analysis

    New Insight on Medieval Painting in Sicily: The Virgin Hodegetria Panel in Monreale Cathedral (Palermo, Italy)

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    : The Virgin Hodegetria, located in the Cathedral of Santa Maria Nuova in Monreale, near Palermo (Italy), probably dating the first half of the 13th century, is one of the earliest examples of medieval panel painting in Sicily. A diagnostic campaign was carried out on the panel aiming to identify the constituting materials and the executive technique, as well as to assess the state of conservation for supporting the methodological choice of the restoration intervention. Both non invasive (X-ray radiography, digital microscope, multispectral imaging, ED-X-ray fluorescence) and micro-invasive (polarised light microscopy, ESEM-EDX, ATR-FTIR spectroscopy and micro-Raman spectroscopy) analyses were performed. According to the results, the executive technique followed the 13th–14th-century Italian painting tradition. A complex structure was applied on the wooden support, consisting of a double layer of canvas and several ground layers of gypsum and glue based binder. The underdrawing was made by a brush using carbonaceous black pigment. The original palette includes red ochre, red lead, azurite, carbon black and bone black. During the several restorations, mercury-based red, indigo, smalt blue, orpiment and synthetic mars were used. The original silver leaf of the frame was covered with red tin-based lake and subsequently regilded with gold leaf. Proteinaceous and oil binders were also detecte
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