Search results for "flux"

Identification of blanket design points using an integrated multi-physics approach

2017

Abstract The breeding blanket (BB) is one of the key components for a fusion reactor. It is expected to sustain and remove considerable heat loads due to the heat flux coming from the plasma and the nuclear power deposited by the fusion neutrons. In the design of the BB, the engineering requirements of nuclear, material and safety kind are involved. In the European DEMO project, several efforts are dedicated to the development of an integrated simulation-design tool able to perform a multi-physics analysis, allowing the characterisation of BB design points which are consistent from the neutronic, thermal-hydraulic and thermo-mechanical point of view. Furthermore, at Karlsruhe Institute of T…

Nitrous oxide fluxes from permafrost regions

2020

This dataset is a synthesis of published nitrous oxide (N2O) fluxes from permafrost-affected soils in Arctic, Antarctic, and Alpine permafrost regions. The data includes mean N2O flux rates measured under field (in situ) conditions and in intact plant-soil systems (mesocosms) under near-field conditions. The dataset further includes explanatory environmental parameters such as meteorological data, soil physical-chemical properties, as well as site and experimental information. Data has been synthesized from published studies (see 'Further details'), and in some cases the authors of published studies have been contacted for additional site-level information. The dataset includes studies publ…

Thermoconvective instability and local thermal non-equilibrium in a porous layer with isoflux-isothermal boundary conditions

2014

The effects of lack of local thermal equilibrium between the solid phase and the fluid phase are taken into account for the convective stability analysis of a horizontal porous layer. The layer is bounded by a pair of plane parallel walls which are impermeable and such that the lower wall is subject to a uniform flux heating, while the upper wall is isothermal. The local thermal non-equilibrium is modelled through a two-temperature formulation of the energy exchange between the phases, resulting in a pair of local energy balance equations: one for each phase. Small-amplitude disturbances of the basic rest state are envisaged to test the stability. Then, the standard normal mode procedure is…

Experimental and Numerical Simulations of Flow and Heat Transfer in Heat Exchanger Elements Using Liquid Crystal Thermography

2004

Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions. The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully deve…

Methane oxidation at a surface-sealed boreal landfill.

2009

Abstract Methane oxidation was studied at a closed boreal landfill (area 3.9 ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable layer into the top soil cover. Mean methane emissions at the 25 measuring points at four measurement times (October 2005–June 2006) were 0.86–6.2 m 3  ha −1  h −1 . Conservative estimates indicated that at least 25% of the methane flux entering the soil cover at the measuring…

Author's reply: Laryngopharyngeal reflux as a potential cause of persistent local neck symptoms after total thyroidectomy.

2020

P1082COMPARISON OF THE REMOVAL OF PROTEIN-BOUND TOXINS AND LARGE MIDDLE MOLECULES WITH HIGH-FLUX PMMA AND MEDIUM CUT-OFF DIALYZERS

2020

Abstract Background and Aims Dialytic clearance of protein-bound toxins and large middle molecules is poor by diffusive treatment and limited by high-flux hemodialysis (HD) and on-line hemodiafiltration (OL-HDF), and only a few studies have examined how to improve their removal by other extracorporeal strategies. Since 2017, there is a new generation of polymethyl methacrylate (PMMA) membranes that suppress platelet adhesion on the membrane surface improving hemocompatibility and permeability, while also maintaining adsorption properties related to conventional PMMA membranes. Expanded HD (HDx) with medium cut-off (MCO) membranes has also recently been incorporated into clinical practice an…

Advanced Monitoring of Rotor Broken Bar in Double Squirrel Cage Induction Machines Based on Wavelet Analysis

2012

The diagnosis of induction machine faults is commonly realized through Motor Current Signature Analysis (MCSA), i.e. by classical spectrum analysis of the input currents. In case of large or double cage induction motors, rotor broken bars fault detection based on sideband current components may fail due to the presence of inter bar currents that reduce the degree of rotor asymmetry, leading to reduced relevance of these spectral components. But inter bar currents produce core vibrations in the axial direction, which can be detected using vibration analysis techniques, in order to overcome the limits of the classical MCSA for these purposes. In this paper, an advanced use of the Discrete wav…

Design of a transverse flux machine for power generation from seawaves

2014

In this paper, we present a transverse flux linear generator. We investigate the possibility to use this generator to extract energy from seawaves. We propose an optimization procedure that allows us to obtain an optimized design of the generator. The optimized design of the converter shows a power generation capability index much higher than other renewable systems.

The pattern of radiative heating and cooling in the troposphere and lower stratosphere

1956

For any meteorological effects of radiation, only those constituents of the air which have a very strong absorption in the infra-red are involved; these are water vapour and carbon dioxide. Several methods have been developed (Mügge & Möller 1932 a, b ; Elsasser 1942; Yamamoto 1952) for computing the radiation flux, and numerous calculations of these fluxes and of the cooling rates have been performed in the last 25 years (Ludwig 1935; Kortiim 1939; Thompson & Neiburger 1955). The results are summarized in figure 1, which shows the distribution of the tem­perature and of the cooling rate by water vapour in some characteristic atmospheres. The lower levels of the tropical atmosphere…