Search results for " flux"
showing 10 items of 583 documents
Effect of space charge on the negative oxygen flux during reactive sputtering
2017
Negative ions often play a distinctive role in the phase formation during reactive sputter deposition. The path of these high energetic ions is often assumed to be straight. In this paper, it is shown that in the context of reactive magnetron sputtering space charge effects are decisive for the energetic negative ion trajectories. To investigate the effect of space charge spreading, reactive magnetron sputter experiments were performed in compound mode with target materials that are expected to have a high secondary ion emission yield (MgO and CeO2). By the combination of energy flux measurements, and simulations, a quantitative value for the negative oxygen ion yield can be derived.
Design and experimental validation of a magnetic device for stem cell culture.
2020
Cell culture of bone and tendon tissues requires mechanical stimulation of the cells in order to mimic their physiological state. In the present work, a device has been conceived and developed to generate a controlled magnetic field with a homogeneous gradient in the working space. The design requirement was to maximize the magnetic flux gradient, assuring a minimum magnetizing value in a 15 mm × 15 mm working area, which highly increases the normal operating range of this sort of devices. The objective is to use the machine for two types of biological tests: magnetic irradiation of biological samples and force generation on paramagnetic particles embedded in scaffolds for cell culture. The…
Modelling of expected B, C, N and O Lyman-α line intensities emitted from W7-X plasmas and measured by means of the W7-X light impurity monitor system
2021
AbstractThe “C/O Monitor” for Wendelstein 7-X (W7-X) is a dedicated light impurity XUV spectrometer intended to measure Lyman-α transitions of hydrogen-like ions of four low-Z impurities—boron (4.9 nm), carbon (3.4 nm), nitrogen (2.5 nm) and oxygen (1.9 nm). Since the discussed diagnostic will deliver continuous information about the line intensities, it is crucial to understand the origin of the obtained signals with respect to the experimental plasma conditions (electron temperature and density). This, however, might be difficult because of the broad acceptance angle of the spectrometer and irregular shape of the plasma edge or SOL where the radiation is expected to mostly come from, depe…
Estimation of Photon Flux of the Oxygen Lyman-alpha Line Emitted from the W7-X Plasmas
2020
The low-Z impurities of the magnetic confined fusion plasmas can provide important information about the wall condition and plasma–wall interactions. In order to accomplish this aim, a special spectrometer called “C/O Monitor” was designed for the W7-X experiment. This system is dedicated to measure Lyman-α transitions of four low-Z impurities: carbon (3.4 nm), oxygen (1.9 nm), nitrogen (2.5 nm) and boron (4.9 nm). It is a high throughput and high time resolution spectrometer which allows to measure the line intensities evolution of indicated elements including information of the background (continuum). The designed spectrometer consists of two vacuum chambers positioned nearly horizontally…
A comprehensive in situ and remote sensing data set from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign
2019
The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign was carried out north-west of Svalbard (Norway) between 23 May and 6 June 2017. The objective of ACLOUD was to study Arctic boundary layer and mid-level clouds and their role in Arctic amplification. Two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. Both aircraft were equipped with identical instrumentation for measurements of basic meteorological parameters, as well as for turbulent and radiative energy fluxes. In addition, on Polar 5 active and passive remote sensing instruments were installed, while Polar 6 …
Geographic and temporal variations in turbulent heat loss from lakes : A global analysis across 45 lakes
2018
Heat fluxes at the lake surface play an integral part in determining the energy budget and thermal structure in lakes, including regulating how lakes respond to climate change. We explore patterns in turbulent heat fluxes, which vary across temporal and spatial scales, using in situ high-frequency monitoring data from 45 glob- ally distributed lakes. Our analysis demonstrates that some of the lakes studied follow a marked seasonal cycle in their turbulent surface fluxes and that turbulent heat loss is highest in larger lakes and those situated at low latitude. The Bowen ratio, which is the ratio of mean sensible to mean latent heat fluxes, is smaller at low lati- tudes and, in turn, the rel…
New advances in dial-lidar-based remote sensing of the volcanic CO2 flux
2017
We report here on the results of a proof-of-concept study aimed at remotely sensing the volcanic CO2 flux using a Differential Adsorption lidar (DIAL-lidar). The observations we report on were conducted on June 2014 on Stromboli volcano, where our lidar (LIght Detection And Ranging) was used to scan the volcanic plume from ~ 3 km distance from the summit vents. The obtained results prove that a remotely operating lidar can resolve a volcanic CO2 signal of a few tens of ppm (in excess to background air) over km-long optical paths. We combine these results with independent estimates of plume transport speed (from processing of UV Camera images) to derive volcanic CO2 flux time-series of ≈16-3…
Understanding the SO 2 degassing budget of Mt Etna’s paroxysms: First clues from the december 2015 sequence
2019
The persistent open-vent activity of basaltic volcanoes is periodically interrupted by spectacular but hazardous paroxysmal explosions. The rapid transition from quiescence to explosive eruption poses a significant challenge for volcanic hazard assessment and mitigation, and improving our understanding of the processes that trigger these paroxysmal events is critical. Although magmatic gas is unquestionably the driver, direct measurements of a paroxysm’s gas flux budget have remained challenging, to date. A particularly violent paroxysmal sequence took place on Etna on December 2015, intermittently involving all summit craters, especially the Voragine (VOR) that had previously displayed no…
Strombolian eruptions and dynamics of magma degassing at Yasur Volcano (Vanuatu)
2020
Abstract Open vent basaltic volcanoes account for a substantial portion of the global atmospheric outgassing flux, largely through passive degassing and mild explosive activity. We present volcanic gas flux and composition data from Yasur Volcano, Vanuatu collected in July 2018. The average volcanic plume chemistry is characterised by a mean molar CO2/SO2 ratio of 2.14, H2O/SO2 of 148 and SO2/HCl of 1.02. The measured mean SO2 flux in the period of 6th to 9th July is 4.9 kg s−1. Therefore, the mean fluxes of the other species are 7.5 kg∙s−1 CO2, 208 kg∙s−1 H2O and 4.8 kg∙s−1 HCl. The degassing regime at Yasur volcano ranges from ‘passive’ to ‘active’ styles, with the latter including Stromb…
A tale of two emergences: Sunrise II observations of emergence sites in a solar active region
2017
R. Centeno et. al.