940 research outputs found

    Unconditional convergence and invertibility of multipliers

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    In the present paper the unconditional convergence and the invertibility of multipliers is investigated. Multipliers are operators created by (frame-like) analysis, multiplication by a fixed symbol, and resynthesis. Sufficient and/or necessary conditions for unconditional convergence and invertibility are determined depending on the properties of the analysis and synthesis sequences, as well as the symbol. Examples which show that the given assertions cover different classes of multipliers are given. If a multiplier is invertible, a formula for the inverse operator is determined. The case when one of the sequences is a Riesz basis is completely characterized.Comment: 31 pages; changes to previous version: 1.) the results from the previous version are extended to the case of complex symbols m. 2.) new statements about the unconditional convergence and boundedness are added (3.1,3.2 and 3.3). 3.) the proof of a preliminary result (Prop. 2.2) was moved to a conference proceedings [29]. 4.) Theorem 4.10. became more detaile

    Self-induced compactness in Banach spaces

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    We consider the question: is every compact set in a Banach space X contained in the closed unit range of a compact (or even approximable) operator on X? We give large classes of spaces where the question has an affirmative answer, but observe that it has a negative answer, in general, for approximable operators. We further construct a Banach space failing the bounded compact approximation property, though all of its duals have the metric compact approximation propert

    Optimal quantum tomography for states, measurements, and transformations

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    We present the first complete optimization of quantum tomography, for states, POVMs, and various classes of transformations, for arbitrary prior ensemble and arbitrary representation, giving corresponding feasible experimental schemes.Comment: 4 pages, 1 figur

    On sequence spaces for Fr\'echet frames

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    We analyze the construction of a sequence space Θ~\widetilde{\Theta}, resp. a sequence of sequence spaces, in order to have {gi}\{g_i\} as a Θ~\widetilde{\Theta}-frame or Banach frame for a Banach space XX, resp. pre-FF-frame or FF-frame for a Fr\'echet space XF=sN0XsX_F=\cap_{s\in {\mathbb N}_0} X_s, where {Xs}sN0\{X_s\}_{s\in {\mathbb N}_0} is a sequence of Banach spaces

    A circular economy approach for olive oil industry: From olive pomace to microalgal biomass

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    In this work olive pomace was used to recover high added value compounds and produce biogas by anaerobic digestion. Moreover, in order to satisfy the circular economy concept, the digestate from the latter process was used as medium for the microalga Chlorella vulgaris growth

    Elevation modelling and palaeo-environmental interpretation in the Siwa area (Egypt): Application of SAR interferometry and radargrammetry to COSMO-SkyMed imagery

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    PublishedJournal Article© 2015 Elsevier B.V. Digital elevation models produced from COSMO-SkyMed imagery were used to delineate palaeo-drainage in a wide area surrounding the Siwa and Al-Jaghbub oases of the western Sahara Desert (Egypt and Libya).This new generation of synthetic aperture radar imagery is suitable for this purpose because of its high spatial resolution and capacity to penetrate dry surface sediments. Different techniques such as radar interferometry and radargrammetry were used to produce digital elevation models. These were assessed for accuracy and then combined to produce a single elevation model of the area. The resulting elevation model was used to support the geological study and palaeo-environmental interpretation of the area. It revealed buried features of the landscape, including inactive palaeo-drainage systems. Drainage features were extracted from the elevation model using geographical information systems; results were combined and assessed with respect to geological field data, as well as data from the literature. Previous studies in the area suggest that a wide river, probably the old Nile River, flowed into the Libyan palaeo-Sirte before the Late Messinian drawdown of the Mediterranean Sea. During the Late Messinian lowering of the sea the fluvial system changed shape and carved deep canyons throughout north-eastern Africa. The reported findings on the key Siwa area were used to precisely delineate the physiography of the modern drainage network and to confirm findings from our previous geological research in the area.We gratefully acknowledge Ruggero Matteucci and Johannes Pignatti (La Sapienza, University of Rome), Francesco Checchi (ENI S.p.A., IOEC), Filippo Bonciani and Debora Graziosi (University of Siena) for their collaboration. Research was supported by the ASI (Id 2262) in the framework of the COSMO-SkyMed Announcement of Opportunity project “Application of COSMO-SkyMed data for geological researches in Egypt and Libya”

    A Comprehensive Optimization of Ultrasound\u2010Assisted Extraction for Lycopene Recovery from Tomato Waste and Encapsulation by Spray Drying

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    This study aimed to extract bioactive compounds from tomato waste through ultrasoundassisted extraction (UAE), using ethanol as solvent. Process optimization was carried out by a central composite design of 33 runs for response surface modelling, simultaneously analyzing the effect of temperature (T), time (t), volume (V), liquid\u2010to\u2010solid ratio (L/S), amplitude (A), the pulser duration (on), and their interaction. The best conditions found by the desirability method (T = 65 \ub0C, t = 20 min, L/S = 72 mL/g, A = 65%, on = 33 s, V = 90 mL) were experimentally verified, leading to the production of an extract with interesting properties (total carotenoids of 1408 \ub114 \u3bcglycopene equivalents/g, lycopene yield of 1536 \ub1 53 \u3bcg/g, 36.1 \ub1 0.9 \u3bcgtrolox equivalents/g as antiradical power). Due to the instability of lycopene, the extract encapsulation by spray drying was undertaken using inulin and maltodextrins as coating agents. The evaluation of wall material composition provided high product recovery (73%), a high content of encapsulated compared to superficial lycopene (15.3 \ub1 2.9 and 0.30 \ub1 0.02 \u3bcg/g), and a product with good water solubility. The novelty of this work concerned the simultaneous study of the effect and interdependences of the UAE parameters, and the use of inulin to enhance the properties of microparticles

    Solid wastes wastewater and remediation costs in an urban slum: The case study of A Gypsy Camp in Napoli (S Italy)

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    Slums represent a sort of black box within the urban environment, generating multiple impacts, that are often acknowledged, but forgotten by urban planners and policy-makers when envisioning the future of cities, due to the dimension of social exclusion in which slum dwellers live. These criticalities pose a further threat to urban sustainability. The first problem is revealed by the lack of quantifications about many environmental and socio-economic factors, as well as by a general lack of understanding about slums as systems. This study is aimed at overcoming the present knowledge weakness, developing a preliminary site-specific system representation of a slum as a system. In particular, a case study of a Gypsy camp in Napoli (S Italy) was chosen for such a purpose. Focusing on solid waste, an approximate evaluation of informal waste picking activity was performed. Basic parameters of generated wastewater, which is dispersed in the environment due to the absence of any sewerage infrastructure, are accounted according to environmental engineering standards. In addition, considering a second abandoned camp (Brecce Sant'Erasmo, Napoli, Italy), specific-site remediation costs were calculated. Results evidence the necessity of a better understanding of resources flows within slums. A first planning action for the studied area would be to separate the areas for waste processing with respect to living areas. Basic infrastructures for solid waste and wastewater management are also necessary to improve the life quality of slum dwellers, while reducing the existing impacts. Finally, also a study to detail atmospheric emissions characteristics would be desirable. Specific upgrading solutions are indicated on the basis of the existing literature. They include planning and monitoring actions, together with the development of engineered solutions for waste and wastewater management
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