1,072 research outputs found
Heterochrony, generic distinction and phylogeny in the family Hydractiniidae (Hydrozoa, Cnidaria)
The taxonomy of Hydractinia, Stylactaria and Podocoryna is discussed and the three genera are merged into Hydractinia since their diagnostic characters are liable to lead to polyphyly and paraphyly, due to repeated episodes of medusa reduction via heterochrony (paedomorphosis). The phylogeny of the Hydractiniidae is reconstructed by using two outgroups, Clava and Cytaeis, both having some characters in common with the Hydractiniidae. The resulting phylogenetic trees agree in identifying affinities among Hydractinia, Kinetocodium and Hydrocorella, all with polymorphic colonies with gastrozooids having oral tentacles. The position of Clavactinia (characterized by gastrozooids with widely scattered tentacles) is at the root of the tree if Clava is the outgroup, whereas it becomes apical when the outgroup is Cytaeis. The pattern of medusa suppression is different in the two cladograms, since the presence of a medusa is a plesiomorphic feature when Cytaeis is the outgroup, whereas it becomes apomorphic when the outgroup is Clava. These inconveniences are difficult to accommodate, since medusa suppression has occurred many times in the evolution of the hydroidomedusae, and Recent species do not witness past paedomorphic events of medusa reduction properly, so that many intermediate states are probably missing
Element-resolved x-ray ferrimagnetic and ferromagnetic resonance spectroscopy
We report on the measurement of element-specific magnetic resonance spectra
at gigahertz frequencies using x-ray magnetic circular dichroism (XMCD). We
investigate the ferrimagnetic precession of Gd and Fe ions in Gd-substituted
Yttrium Iron Garnet, showing that the resonant field and linewidth of Gd
precisely coincide with Fe up to the nonlinear regime of parametric
excitations. The opposite sign of the Gd x-ray magnetic resonance signal with
respect to Fe is consistent with dynamic antiferromagnetic alignment of the two
ionic species. Further, we investigate a bilayer metal film,
NiFe(5 nm)/Ni(50 nm), where the coupled resonance modes of Ni and
NiFe are separately resolved, revealing shifts in the resonance
fields of individual layers but no mutual driving effects. Energy-dependent
dynamic XMCD measurements are introduced, combining x-ray absorption and
magnetic resonance spectroscopies.Comment: 16 pages, 8 figure
Investigation on the Performance of a Compact Three-Fluid Combined Membrane Contactor for Dehumidification in Electric Vehicles
In this paper, the performance of a compact Three-Fluid Combined Membrane Contactor (3F-CMC) is investigated using Computational Fluid Dynamics (CFD), supported and validated with a good agreement by an experimental campaign made on a fully working prototype. This internally-cooled membrane contactor is the core component of a hybrid air conditioning system for electric vehicles (EVs) developed in a successful H2020 project called XERIC. In the adopted numerical approach, the conjugate heat and mass transfer inside the 3F-CMC is described by non-isothermal incompressible flows and vapor transport through a PTFE hydrophobic membrane. The sensitivity of the 3F-CMC performance to air/desiccant flow rates, temperature, humidity, and desiccant concentration is analyzed numerically through the validated CFD codes. According to this study, the moisture removal increases by the inlet humidity ratio, nearly linearly. Under the considered conditions (where the inlet air temperature is 26.2C), when the inlet relative humidity (RH) is 75% the moisture removal is about 450% higher than the case RH = 37%, while the absorption effectiveness declines about 45%. Furthermore, this study shows that the amount of absorbed vapor flux rises by increasing the airflow rate; on the other hand, the higher the airflow rate, the lower is the overall absorption efficiency of the 3F-CMC. This investigation gives important suggestions on how to properly operate a 3F-CMC in order to achieve the requested performance, especially in hot and humid climates
Ab-initio study of oxygen vacancies in alpha-quartz
Extrinsic levels, formation energies, and relaxation geometries are
calculated ab initio for oxygen vacancies in alpha-quartz SiO2. The vacancy is
found to be thermodynamically stable in the charge states Q=+3, Q=0, Q=--2, and
Q=-3. The charged states are stabilized by large and asymmetric distortions
near the vacancy site. Concurrently, Franck-Condon shifts for absorption and
recombination related to these states are found to be strongly asymmetric. In
undoped quartz, the ground state of the vacancy is the neutral charge state,
while for moderate p-type and n-type doping, the +3 and -3 states are favored,
respectively, over a wide Fermi level window. Optical transitions related to
the vacancy are predicted at around 3 eV and 6.5 eV (absorption) and 2.5 to 3.0
eV (emission), depending on the charge state of the ground state.Comment: 6 figures included, but only Fig.1 actually change
Model for energy analysis of Miscanthus production and transportation
A computational tool is developed for the estimation of the energy requirements of Miscanthus x giganteus on individual fields that includes a detailed analysis and account of the involved in-field and transport operations. The tool takes into account all the individual involved in-field and transport operations and provides a detailed analysis on the energy requirements of the components that contribute to the energy input. A basic scenario was implemented to demonstrate the capabilities of the tool. Specifically, the variability of the energy requirements as a function of field area and field-storage distance changes was shown. The field-storage distance highly affects the energy requirements resulting in a variation in the efficiency if energy (output/input ratio) from 15.8 up to 23.7 for the targeted cases. Not only the field-distance highly affects the energy requirements but also the biomass transportation system. Based on the presented example, different transportation systems adhering to the same configuration of the production system creates variation in the efficiency of energy (EoE) between 12.9 and 17.5. The presented tool provides individualized results that can be used for the processes of designing or evaluating a specific production system since the outcomes are not based on average norms
Project "Biodiversity MARE Tricase": a biodiversity inventory of the coastal area of Tricase (Ionian Sea, Italy) – Mollusca: Heterobranchia
The marine biodiversity of the Tricase coastal area (Ionian Sea, Italy) was investigated at the MARE Outpost (Avamposto MARE) between 2016 and 2017, with the help of citizen scientists and trained taxonomists. Among the most interesting groups encountered, heterobranch molluscs deserve a special mention. Altogether, 268 specimens were ascribed to this group and referred to 49 taxa. Notwithstanding the extensive literature on Mediterranean heterobranchs, two species proved to be new to the Italian coasts, the records of eight species represented their easternmost sightings in the Mediterranean Sea, and 13 taxa represented new records for the Ionian Sea. In addition, several feeding habits and phenological events were new to science. Although the European Union's Marine Strategy Framework Directive lists "Biodiversity is maintained" as the first descriptor in achieving "Good Environmental Status", our results highlighted the presence of conspicuous gaps in the knowledge of species distribution, taxonomy and ecology of heterobranch molluscs, indicating the necessity of even small-scale species checklists to understand biodiversity changes in worldwide biota
CoCoNet: towards coast to coast networks of Marine Protected Areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential.
Abstract
This volume contains the main results of the EC FP7 “The Ocean of Tomorrow” Project CoCoNet, divided in two
sections: 1) a set of guidelines to design networks of Marine Protected Areas in the Mediterranean and the Black Seas;
2) a smart wind chart that will allow evaluating the possibility of installing Offshore Wind Farms in both seas. The
concept of Cells of Ecosystem Functioning, based on connectivity, is introduced to define natural units of management
and conservation. The definition of Good Environmental Status, as defined in the Marine Strategy Framework
Directive, is fully embraced to set the objectives of the project, by adopting a holistic approach that integrates a full set
of disciplines, ranging from physics to bio-ecology, economics, engineering and many sub-disciplines. The CoCoNet
Consortium involved scientist sfrom 22 states, based in Africa, Asia, and Europe, contributing to build a coherent
scientific community
Microscopic four-point probe based on SU-8 cantilevers
A microscopic four-point probe (u4PP) for resistivity measurements on thin films was designed and fabricated using the negative photoresist SU-8 as base material. The device consists of four microscopic cantilevers, each of them supporting a probe tip at the extremity. The high flexibility of SU-8 ensures a stable electrical point contact between samples and probe tip with all four electrodes even on rough surfaces. With the presented surface micromachining process, u4PPs with a probe-to-probe spacing of 10–20 um were fabricated. Resistivity measurements on thin Au, Al, and Pt films were performed successfully. The measured sheet resistances differ by less than 5% from those obtained by a commercial macroscopic resistivity meter. Due to the low contact forces (Fcont10^6 ohm/
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