1,042 research outputs found
Coos county teens’ family relationships
This fact sheet examines Coos County, New Hampshire teens’ perceptions of their family relationship experiences using data from the Coos Youth Study collected in 2011 from 418 eleventh graders in all Coos County public schools. Authors Corinna Jenkins Tucker and Desiree Wiesen-Martin report that Coos older adolescents feel close to their parents and siblings but also argue with them. A small group of youths report perpetrating violence on a family member
Technical Note: Quantification of interferences of wet chemical HONO measurements under simulated polar conditions
International audienceIn the present pilot study, an optimized LOPAP instrument for the detection of nitrous acid (HONO) in the atmosphere (DL 0.2 pptV) was tested at the high alpine research station "Jungfraujoch" at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5?50 pptV with an average of 7.5 pptV were observed at the "Jungfraujoch". The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the correction of interferences is of paramount importance for those instruments, which sample HONO on aqueous or humid surfaces
Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions
In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer) for the detection of nitrous acid (HONO) in the atmosphere (DL 0.2 pptV) was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range &lt;0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data
Towards a unified linear kinetic transport model with the trace ion module for EIRENE
Linear kinetic Monte Carlo particle transport models are frequently employed
in fusion plasma simulations to quantify atomic and surface effects on the main
plasma flow dynamics. Separate codes are used for transport of neutral
particles (incl. radiation) and charged particles (trace impurity ions).
Integration of both modules into main plasma fluid solvers provides then self
consistent solutions, in principle. The required interfaces are far from
trivial, because rapid atomic processes in particular in the edge region of
fusion plasmas require either smoothing and resampling, or frequent transfer of
particles from one into the other Monte Carlo code. We propose a different
scheme here, in which despite the inherently different mathematical form of
kinetic equations for ions and neutrals (e.g. Fokker-Planck vs. Boltzmann
collision integrals) both types of particle orbits can be integrated into one
single code. We show that the approximations and shortcomings of this "single
sourcing" concept (e.g., restriction to explicit ion drift orbit integration)
can be fully tolerable in a wide range of typical fusion edge plasma
conditions, and be overcompensated by the code-system simplicity, as well as by
inherently ensured consistency in geometry (one single numerical grid only) and
(the common) atomic and surface process modulesComment: 15 pages, 7 figure
Beryllium global erosion and deposition at JET-ILW simulated with ERO2.0
The recently developed Monte-Carlo code ERO2.0 is applied to the modelling of limited and diverted discharges at JET with the ITER-like wall (ILW). The global beryllium (Be) erosion and deposition is simulated and compared to experimental results from passive spectroscopy. For the limiter configuration, it is demonstrated that Be self-sputtering is an important contributor (at least 35%) to the Be erosion. Taking this contribution into account, the ERO2.0 modelling confirms previous evidence that high deuterium (D) surface concentrations of up to similar to 50% atomic fraction provide a reasonable estimate of Be erosion in plasma-wetted areas. For the divertor configuration, it is shown that drifts can have a high impact on the scrape-off layer plasma flows, which in turn affect global Be transport by entrainment and lead to increased migration into the inner divertor. The modelling of the effective erosion yield for different operational phases (ohmic, L- and H-mode) agrees with experimental values within a factor of two, and confirms that the effective erosion yield decreases with increasing heating power and confinement.EURATOM 63305
Flux surface mapping in non-nested topologies and its acceleration with deep neural networks on Wendelstein 7-X
Recent progress of plasma exhaust concepts and divertor designs for tokamak DEMO reactors
The power exhaust concept and an appropriate divertor design are common critical issues for tokamak DEMO
design activities which have been carried out in Europe, Japan, China, Korea and the USA. Conventional divertor
concepts and power exhaust studies for recent DEMO designs (Pfusion = 1 – 2 GW, Rp = 7 – 9 m) are reviewed
from the viewpoints of the plasma physics issues and the divertor engineering design. Radiative cooling is a
common approach for the power fusion scenario. Requirements on the main plasma radiation fraction (frad
main =
Prad
main/Pheat) and the plasma performance constrain the divertor design concept. Different challenges contribute to
optimizing the future DEMO designs: for example, (i) increasing the main plasma radiation fraction for ITER level Psep/Rp designs and simplifying the divertor geometry, and (ii) extending ITER divertor geometry with
increasing divertor radiation (Prad
div) for larger Psep/Rp ≥ 25MWm− 1 designs. Power exhaust simulations with large
Psep = 150 – 300 MW have been performed using integrated divertor codes considering an ITER-based divertor
geometry with longer leg length (1.6 – 1.7 m), as in a common baseline design. Geometry effects (ITER like
geometry or more open one without baffle) on the plasma detachment profile and the required divertor radiation
fraction (frad
div = Prad
div/Psep) were key aspects of these studies. All simulations showed that the divertor plasma
detachment were extended widely across the target plate with a reduction in the peak heat load of qtarget ≤ 10
MWm− 2 for the large frad
div = 0.7 – 0.8, while the peak qtarget location and value were noticeably different in the
partially detached divertor. Simulation results also demonstrated that radial diffusion coefficients of the heat and
particle fluxes were critical parameters for DEMO divertor design, and that effects of plasma drifts on outboard enhanced asymmetry of the heat flux, suggested the need for longer divertor leg to ensure the existence of a
detached divertor operation with qtarget ≤ 10 MWm− 2
.
Integrated design of the water cooled divertor target, cassette body (CB) and cooling pipe routing has been
developed for each DEMO concept, based on the ITER-like tungsten monoblock (W-MB) with Cu-alloy cooling
pipes. Engineering design adequate under higher neutron irradiation condition was required. Therefore, inlet
coolant temperature (Tcool) was increased. In current designs, it still shows a large potential variation between
70 ◦C and 200 ◦C. The influence of thermal softening on the Cu-alloy (CuCrZr) pipe was fostered near the strike point when the high qtarget of ~10 MWm− 2 was studied. Improved technologies for high heat flux components
based on the ITER W-MB unit have been developed for EU-DEMO. Different coolant conditions (low- and high Tcool) were provided for Cu-alloy and reduced activation ferritic martensitic (RAFM) steel heat sink units,
respectively. The high-Tcool coolant was also considered for the CB and supporting structures. Appropriate
conditions for the high-Tcool coolant, i.e. 180 â—¦C/ 5 MPa (EU-DEMO) and 290 â—¦C/ 15 MPa (JA-DEMO, CFETR and
K-DEMO), will be determined in the future optimizations of the divertor and DEMO design
Estrogen regulation of mammary gland development and breast cancer: amphiregulin takes center stage
Estrogen-mediated proliferation is fundamental to normal mammary gland development. Recent studies have demonstrated that amphiregulin is a critical paracrine regulator of estrogen action during ductal morphogenesis. These studies implicate a critical role for amphiregulin in mammary stem cell differentiation as well as breast cancer initiation and progression
Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.
A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions
EUROfusion-theory and advanced simulation coordination (E-TASC) : programme and the role of high performance computing
This paper is a written summary of an overview oral presentation given at the 1st Spanish Fusion High Performance Computer (HPC) Workshop that took place on the 27 November 2020 as an online event. Given that over the next few years ITER24 will move to its operation phase and the European-DEMO design will be significantly advanced, the EUROfusion consortium has initiated a coordination effort in theory and advanced simulation to address some of the challenges of the fusion research in Horizon EUROPE (2021-2027), i.e. the next EU Framework Programme for Research and Technological Development. This initiative has been called E-TASC, which stands for EUROfusion-Theory and Advanced Simulation Coordination. The general and guiding principles of E-TASC are summarized in this paper. In addition, an overview of the scientific results obtained in the pilot phase (2019-2020) of E-TASC are provided while highlighting the importance of the required progress in computational methods and HPC techniques. In the initial phase, five pilot theory and simulation tasks were initiated: towards a validated predictive capability of the low to high transition and pedestal physics; runaway electrons in tokamak disruptions in the presence of massive material injection; fast code for the calculation of neoclassical toroidal viscosity in stellarators and tokamaks; development of a neutral gas kinetics modular code; European edge and boundary code for reactor-relevant devices. In this paper, we report on recent progress made by each of these projects.Peer reviewe
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