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Marchettiite, (NH4)C5H3N4O3, a new organic mineral from Mount Cervandone, Devero Valley, Western–Central Alps, Italy
- Alessandro Guastoni, Fabrizio Nestola, Federico Zorzi, Arianna Lanza, Michelle Ernst, Paolo Gentile, Sergio Andò, Alessandra Lorenzetti
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- Journal:
- Mineralogical Magazine / Volume 86 / Issue 6 / December 2022
- Published online by Cambridge University Press:
- 19 August 2022, pp. 966-974
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The new mineral marchettiite (IMA2017-066) is the natural equivalent of ammonium hydrogen urate. It has a simple molecular formula C5H7N5O3 and can be alternatively written as (NH4)C5H3N4O3. Marchettiite was found in a cleft at Mount Cervandone, Devero Valley, Piedmont, Italy, where it occurs as aggregates of opaque pale pink to white, platy prismatic crystals. This mineral has a white streak, dull and opaque lustre, it is not fluorescent and has a hardness of 2–2.5 (Mohs’ scale). The tenacity is brittle and crystals have a good cleavage parallel to {001}. The calculated density is 1.69 g/cm3. Marchettiite is biaxial (–) with 2V of 47.24°; the optical properties of marchettiite were determined by periodic-DFT methods providing the following values: α = 1.372, β = 1.681 and γ = 1.768. No twinning was observed. Electron microprobe analyses gave the following chemical formula: C4.99H6.97N4.91O3.00. Although the small crystal size did not allow refinement of structural data by single-crystal diffraction, we were able to refine the structure by powder micro X-ray diffraction. Marchettiite has space group P$\bar{1}$ and the following unit-cell parameters: a = 3.6533(2) Å, b = 10.2046(7) Å, c = 10.5837(7) Å, α = 113.809(5)°, β = 91.313(8)°, γ = 92.44(1)° and V = 360.312 Å3. The strongest lines in the powder diffraction pattern [d in Å (I)(hkl)] are: 9.784(50)(001); 8.663(80)(01$\bar{1}$); 5.659(100)(011); 3.443(100)(10$\bar{1}$); 3.241(70)(003) and 3.158(100)(1$\bar{1}\bar{1})$. Marchettiite is named after Gianfranco Marchetti, the mineral collector who found this mineral.
Sterilization/disinfection of medical devices using plasma: the flowing afterglow of the reduced-pressure N2-O2 discharge as the inactivating medium
- Michel Moisan, Karim Boudam, Denis Carignan, Danielle Kéroack, Pierre Levif, Jean Barbeau, Jacynthe Séguin, Kinga Kutasi, Benaïssa Elmoualij, Olivier Thellin, Willy Zorzi
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- Journal:
- The European Physical Journal - Applied Physics / Volume 63 / Issue 1 / July 2013
- Published online by Cambridge University Press:
- 10 July 2013, 10001
- Print publication:
- July 2013
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Potential sterilization/disinfection of medical devices (MDs) is investigated using a specific plasma process developed at the Université de Montréal over the last decade. The inactivating medium of the microorganisms is the flowing afterglow of a reduced-pressure N2-O2 discharge, which provides, as the main biocidal agent, photons over a broad ultraviolet (UV) wavelength range. The flowing afterglow is considered less damaging to MDs than the discharge itself. Working at gas pressures in the 400—700 Pa range (a few torr) ensures, through species diffusion, the uniform filling of large volume chambers with the species outflowing from the discharge, possibly allowing batch processing within them. As a rule, bacterial endospores are used as bio-indicators (BI) to validate sterilization processes. Under the present operating conditions, Bacillus atrophaeus is found to be the most resistant one and is therefore utilized as BI. The current paper reviews the main experimental results concerning the operation and characterization of this sterilizer/disinfector, updating and completing some of our previously published papers. It uses modeling results as guidelines, which are particularly useful when the corresponding experimental data are not (yet) available, hopefully leading to more insight into this plasma afterglow system. The species flowing out of the N2-O2 discharge can be divided into two groups, depending on the time elapsed after they left the discharge zone as they move toward the chamber, namely the early afterglow and the late afterglow. The early flowing afterglow from a pure N2 discharge (also called pink afterglow) is known to be comprised of N2+ and N4+ ions. In the present N2-O2 mixture discharge, NO+ ions are additionally generated, with a lifetime that extends over a longer period than that of the nitrogen molecular ions. We shall suppose that the disappearance of the NO+ ions marks the end of the early afterglow regime, thereby stressing our intent to work in an ion-free process chamber to minimize damage to MDs. Therefore, operating conditions should be set such that the sterilizer/disinfector chamber is predominantly filled by N and O atoms, possibly together with long-lived metastable-state O2(1 Δg) (singlet-delta) molecules. Various aspects related to the observed survival curves are examined: the actual existence of two “phases” in the inactivation rate, the notion of UV irradiation dose (fluence) and its implications, the UV photon best wavelength range in terms of inactivation efficiency, the influence of substrate temperature and the reduction of UV intensity through surface recombination of N and O atoms on the object/packaging being processed. To preserve their on-shelf sterility, MDs are sealed/wrapped in packaging material. Porous packaging materials utilized in conventional sterilization systems (where MDs are packaged before being subjected to sterilization) were tested and found inadequate for the N2-O2 afterglow system in contrast to a (non-porous) polyolefin polymer. Because the latter is non-porous, its corresponding pouch must be kept unsealed until the end of the process. Even though it is unsealed, but because the opening is very small the O2(1Δg) metastable-state molecules are expected to be strongly quenched by the pouch material as they try to enter it and, as a result, only N and O atoms, together with UV photons, are significantly present within it. Therefore, by examining a given process under pouch and no-pouch conditions, it is possible to determine what are the inactivating agents operating: (i) when packaged, these are predominantly UV photons, (ii) when unpackaged, O2(1Δg) molecules together with UV photons can be acting, (iii) comparing the inactivation efficiency under both packaged and unpackaged conditions allows the determination of the relative contribution of UV photons (if any) and O2(1Δg) metastable-state molecules. Such a method is applied to pyrogenic molecules and to the enzymatic activity of lysozyme proteins once exposed to the N2-O2 flowing afterglow. Finally, the activity of the infectious prion protein is shown to be reduced when exposed to the present flowing afterglow, as demonstrated by both in vitro and in vivo experiments.
14 - Implementation and performance evaluation of wireless sensor networks for smart grid
- from Part IV - Sensor and actuator networks for smart grid
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- By Nicola Bui, University of Padova, Italy, Angelo P. Castellani, University of Padova, Italy, Paolo Casari, University of Padova, Italy, Michele Rossi, University of Padova, Italy, Lorenzo Vangelista, University of Padova, Italy, Michele Zorzi, University of Padova, Italy
- Edited by Ekram Hossain, University of Manitoba, Canada, Zhu Han, University of Houston, H. Vincent Poor, Princeton University, New Jersey
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- Book:
- Smart Grid Communications and Networking
- Published online:
- 05 January 2013
- Print publication:
- 24 May 2012, pp 324-350
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Summary
Introduction
This chapter focuses on the usage of wireless sensor and actuator networks to provide data connectivity in smart grids. In particular, we discuss the configuration adopted for the implementation of the sensor network test-bed deployed at the Information Engineering Department of the University of Padova, Italy. The test-bed has been designed to reproduce typical deployment scenarios in an urban network by mimicking diverse contexts such as dense building networks, sparse environmental scenarios, and linear deployments along streets.
The test-bed software has been realized taking full advantage of the most advanced solutions provided by the academic community and the standardization bodies by implementing a completely IP interoperable communication framework. Moreover, the latest solutions for the Internet of things [1] have been used to develop a lightweight modular architecture offering services and data sources through simple and efficient web services. All of this facilitates the integration of the test-bed functionalities into flexible web applications, capable of performing the needed monitoring and managing routines in the entire network as well as on single nodes.
The Internet-like approach, coupled with a variety of network configurations, has been used to verify the advantages brought by the usage of constrained wireless communication for smart grids. In particular, we have been able to quantify useful performance metrics, such as maximum throughput, delivery delay, and transmission reliability, in typical smart grid network scenarios. Specifically, these performance metrics were determined for linearly shaped multihop configurations, to address networks deployed along streets, such as those controlling the street lights, as well as for dense single- and multihop configurations to address small-to-medium-sized building deployments.