Scaling properties of a low-actuation pressure microfluidic valve

Using basic physical arguments, we present a design and method for the fabrication of microfluidic valves using multilayer soft lithography. These on-off valves have extremely low actuation pressures and can be used to fabricate active functions, such as pumps and mixers in integrated microfluidic chips. We characterized the performance of the valves by measuring both the actuation pressure and flow resistance over a wide range of design parameters, and compared them to both finite element simulations and alternative valve geometries

The basal part Modino Unit Succession under the belt-foredeep system of the Northern Apennines (Italy)

The Modino Unit turbidite system of the Northern Apennines foreland basin provides an excellent opportunity to study the sedimentary and structural variations within the context of spatial and temporal distribuition of source rocks during the evolution of foreland basins. The substrate of this Unit was interpreted as a stratigraphic-structural mélange (Plesi et al., 2000), the expression of polyphase tectonic phases of Cretaceous-Eocene accretion that have affected the external part of Ligurian and Subligurian domain. In this article we present the preliminary data of different stratigraphic sections outcropping in Tuscan and Emilian regions, with particulary attention to the lower part of Modino Unit Succession, of pre-Ligurian stage, unconformably deposited at the top of the Ligurian and Subligurian substrate, composed by Fiumalbo Shale Fm. and Marmoreto Marl Fm. The tectonic setting of this Unit is complex and necessitated the use of stratigraphical, biostratigraphical and petrographical studies to achieve this goals. The Modino Unit succession is composed by three different formations: The Fiumalbo Shale Fm. followed in some sections of coarse breccia deposits that cover the substrate (Riccovolto Breccia) are made up of mostly red and green shales with intercalations of limestone and turbidite-like sandstones beds more or less extensive (Rio Acquicciola Sandstones Auctt. or M. Sassolera Sandstones Auctt.). The Marmoreto Marl Fm. are characterized by fine emipelagic sediments, have a massive structure (with rare thin layers of fine sandstones). The Monte Modino Sandstone Fm. are constituted by one or more sequences of turbidite facies with quite variable vertically and laterally . Their deposition occurs preferentially in the middle and front al part of the prism and is quickly interrupted, on its southwestern margin, by the thrust belt materials. From this reason the axis of sedimentation moving outwards. A petrographical study on turbidite-like sandstone beds in Fiumalbo Shale Fm., show a petrofacies characterized by a modal composition of Q48F27L+CE25, according with the composition of Monte Modino Sandstone of this study, while shows different composition in the Fine-Grained Rock Fragments Compositional Mode (LmLvLs plot). The sandstones in Fiumalbo Shale Fm., are composed by different tipology of fine grained lithic fragments, and its composition changes strata-strata in the same stratigraphic sections. The fine grained lithic fragments are composed by dominating metamorphic origin clasts and ophiolithic rock fragment associated with unmetamorphic radiolaritic fragments, The biostratigraphical analysis indicate that the age of theese formations is comprised between Lutetian and Chattian ages. These formations reflect a slope environment, with quite deep and with a strong affinity to Epiligurian sections, which resemble the coeval succession Monte Piano-Ranzano and their sedimentation environment reflects a time and an area of major physiographic expression of the prism. The composition of this arenites is interpreted as being controlled mainly by synsedimentary tectonics connected with the evolution of an accretionary prism east vergent. This composition reflects the different stages of the process of accretion and is the expression of the different sedimentary environments that were gradually generating. The lower part of Modino Unit succession seems to be supplied by two different source areas, the classic Alpine source area and a more proximal "Liguride derived" source, maybe located in the proto-appenninic wedge

Constraints on massive sterile neutrino species from current and future cosmological data

Sterile massive neutrinos are a natural extension of the Standard Model of elementary particles. The energy density of the extra sterile massive states affects cosmological measurements in an analogous way to that of active neutrino species. We perform here an analysis of current cosmological data and derive bounds on the masses of the active and the sterile neutrino states as well as on the number of sterile states. The so-called (3+2) models with three sub-eV active massive neutrinos plus two sub-eV massive sterile species is well within the 95% CL allowed regions when considering cosmological data only. If the two extra sterile states have thermal abundances at decoupling, Big Bang Nucleosynthesis bounds compromise the viability of (3+2) models. Forecasts from future cosmological data on the active and sterile neutrino parameters are also presented. Independent measurements of the neutrino mass from tritium beta decay experiments and of the Hubble constant could shed light on sub-eV massive sterile neutrino scenarios.Comment: 9 pages, 7 figures. Journal versio

Dynamics and stability of relativistic GRB blast waves

In gamma-ray-bursts (GRB), ultra-relativistic blast waves are ejected into the circumburst medium. We analyse in unprecedented detail the deceleration of a self-similar Blandford-McKee blast wave from a Lorentz factor 25 to the nonrelativistic Sedov phase. Our goal is to determine the stability properties of its frontal shock. We carried out a grid-adaptive relativistic 2D hydro-simulation at extreme resolving power, following the GRB jet during the entire afterglow phase. We investigate the effect of the finite initial jet opening angle on the deceleration of the blast wave, and identify the growth of various instabilities throughout the coasting shock front. We find that during the relativistic phase, the blast wave is subject to pressure-ram pressure instabilities that ripple and fragment the frontal shock. These instabilities manifest themselves in the ultra-relativistic phase alone, remain in full agreement with causality arguments, and decay slowly to finally disappear in the near-Newtonian phase as the shell Lorentz factor drops below 3. From then on, the compression rate decreases to levels predicted to be stable by a linear analysis of the Sedov phase. Our simulations confirm previous findings that the shell also spreads laterally because a rarefaction wave slowly propagates to the jet axis, inducing a clear shell deformation from its initial spherical shape. The blast front becomes meridionally stratified, with decreasing speed from axis to jet edge.Comment: accepted for publication in A&

A Computational Method for Combustion in High Speed Flows

A two-dimensional time-accurate numerical model to simulate complex reacting flowfields in chemical non-equilibrium is presented. The aim of this studyis to develop a computational tool which permits the analysis and the easy implementation of combustion phenomena for high speed flows. To construct an efficient numerical tool, while maintaining a reasonable accuracy, a semi-implicit numerical method was selected and verified for a hydrogen-air mixture. The numerical approach is based on a time-dependent, finite-volume integration of the governing equations suitably modified for chemical non-equilibrium. The evaluation of the reacting constants based on Gibbs free energy and the Van't Hoff equation allows a very easy implementation of the chemical model used, regardless of its complexity. Calculations were performed with adeguate temporal and spatial resolution for modeling the physical process for pratical calculation. Comparisons with numerical results are used for a verification of the numerical procedur

Hippopotamid dispersal across the Mediterranean in the latest Miocene: A re-evaluation of the Gravitelli record from Sicily, Italy

The first dispersal of Hippopotamidae out of Africa is recorded around 6 Ma, but this event is documented only in a few European localities. Among them, the uppermost Miocene deposits of Gravitelli in Sicily yielded particularly abundant hippopotamid remains. These specimens, published at the beginning of the 20th century, went lost during the 1908 earthquake that destroyed the city of Messina. The specimens from Gravitelli were ascribed to a new species, Hippopotamus siculus; their generic attribution was not questioned during the first half of the past century and they have not been revised in recent decades. The remains of the Gravitelli hippopotamid were mainly represented by isolated teeth and a few postcranial remains. Morphological and dimensional characters of the specimens, such as long lower premolars, lowcrowned molars, a lower canine with longitudinal ridges and a groove on the lateral surface and the overall dimensions suggest that the Sicilian hippopotamid was characterized by plesiomorphic features. The morphology of the specimens collected from Gravitelli is similar to that of Hexaprotodon? crusafonti, Archaeopotamus harvardi, Hexaprotodon sivalensis and Hexaprotodon garyam. Hexaprotodon? siculus is also morphometrically similar to Hexaprotodon sivalensis, but the lower premolars in the former are longer and wider than in the latter. Accordingly, we provisionally refer the Gravitelli hippopotamid to the genus Hexaprotodon. Hexaprotodon? siculus is dimensionally different from the Spanish latest Miocene hippopotamid, herein referred to as Archaeopotamus crusafonti, and the two species are considered as valid taxa. The paleobiogeography of the latest Miocene hippopotamids from the Mediterranean Basin is discussed

Proof-of-principle of a new geometry for sampling calorimetry using inorganic scintillator plates

A novel geometry for a sampling calorimeter employing inorganic scintillators as an active medium is presented. To overcome the mechanical challenges of construction, an innovative light collection geometry has been pioneered, that minimises the complexity of construction. First test results are presented, demonstrating a successful signal extraction. The geometry consists of a sampling calorimeter with passive absorber layers interleaved with layers of an active medium made of inorganic scintillating crystals. Wavelength-shifting (WLS) fibres run along the four long, chamfered edges of the stack, transporting the light to photodetectors at the rear. To maximise the amount of scintillation light reaching the WLS fibres, the scintillator chamfers are depolished. It is shown herein that this concept is working for cerium fluoride (CeF$_3$) as a scintillator. Coupled to it, several different types of materials have been tested as WLS medium. In particular, materials that might be sufficiently resistant to the High-Luminosity Large Hadron Collider radiation environment, such as cerium-doped Lutetium-Yttrium Orthosilicate (LYSO) and cerium-doped quartz, are compared to conventional plastic WLS fibres. Finally, an outlook is presented on the possible optimisation of the different components, and the construction and commissioning of a full calorimeter cell prototype is presented.Comment: Submitted to Proceedings CALOR 2014, the 16th International Conference on Calorimetry in High-Energy Physics, Giessen (Germany) 6 - 11 April 2014. To be published in Journal of Physics: Conference Series (10 pages, 15 figures

Sea-level history of past interglacial periods from uranium-series dating of corals, Curaçao, Leeward Antilles islands

Curaçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~126 to ~118 ka). Elevations and age of this reef show that late Quaternary uplift rates on Curaçao are low, 0.026–0.054 m/ka, consistent with its tectonic setting. Ages of ~200 ka for corals from the older Cortalein unit of the Lower Terrace correlate this reef to MIS 7, with paleo-sea level estimates ranging from −3.3 m to +2.3 m. The estimates are in agreement with those for MIS 7 made fromother localities and indicate that the penultimate interglacial period was a time of significantwarmth, on a parwith the present interglacial period. The ~400 ka (MIS 11) Middle Terrace I on Curaçao, dated by others, may have formed froma paleo-sea level of+8.3 to+10.0 m, or (less likely)+17 mto+20 m. The lower estimates are conservative compared to previous studies, but still require major ice sheet loss from Greenland and Antarctica

Andesitic dyke swarms in the Araç-Boyalı foredeep basin, N Anatolia: Evidence for Eocene extension

A number of dykes and sills have been investigated in the Araç-Boyalı Flysch Basin, a foreland basin formed on the platform of the Sakarya Composite Terrane following the closure of the Intra-Pontide Ocean during the Late Cretaceous – Late Paleocene. The andesitic dyke swarms, characterized by well-developed chilled margins, flow textures and elongated vesicles, intrude the basin sediments, among which massive and pillow lavas, as well as lava and pillow breccias are also found. Major element data plotted on SiO2 indicates plagioclase, pyroxene and biotite fractioation, as well Fe-Ti oxides in the samples, that are andesites and andesitic basalts of calc- alkaline character. Tectono-magmatic discrimination diagrams of lavas as well as the dykes are indicative for destructive plate margin volcanism. Lava and dyke samples display similar patterns in REE and Spider diagrams. A depletion of heavy REE, enrichment of LREE is observed, as well as a marked Nb-Ta trough, characteristic of arc magmas. Based on low Mg numbers, together with low compatible trace element concentrations and low Nb/La ratios, compositions of examined samples might have been modified by assimilation processes. Geochemical characteristics of the volcanic rocks reveal that they are products of continental arc magmatism within the Sakarya Composite Terrane above the N-ward subducting Izmir-Ankara oceanic lithosphere of Neotethys.Similarities in major, minor and trace element geochemistry are in favour of dykes being the feeders of the Eocene lava flows within the Eocene basins that formed as a result of post-collisional extention