Search results for "Heating"

Probing the physics of the solar atmosphere with the Multi-slit Solar Explorer (MUSE): I. Coronal Heating

2022

The Multi-slit Solar Explorer (MUSE) is a proposed NASA MIDEX mission, currently in Phase A, composed of a multi-slit EUV spectrograph (in three narrow spectral bands centered around 171A, 284A, and 108A) and an EUV context imager (in two narrow passbands around 195A and 304A). MUSE will provide unprecedented spectral and imaging diagnostics of the solar corona at high spatial (<0.5 arcsec), and temporal resolution (down to ~0.5s) thanks to its innovative multi-slit design. By obtaining spectra in 4 bright EUV lines (Fe IX 171A , Fe XV 284A, Fe XIX-Fe XXI 108A) covering a wide range of transition region and coronal temperatures along 37 slits simultaneously, MUSE will for the first time …

MAC Design for WiFi Infrastructure Networks: A Game-Theoretic Approach

2011

In WiFi networks, mobile nodes compete for accessing a shared channel by means of a random access protocol called Distributed Coordination Function (DCF). Although this protocol is in principle fair, since all the stations have the same probability to transmit on the channel, it has been shown that unfair behaviors may emerge in actual networking scenarios because of non-standard configurations of the nodes. Due to the proliferation of open source drivers and programmable cards, enabling an easy customization of the channel access policies, we propose a game-theoretic analysis of random access schemes. Assuming that each node is rational and implements a best response strategy, we show that…

FeCr2O4 synthetic spinel: heating experiments and oxidation kinetics

2011

The guardians of European football : UEFA Financial Fair Play and the career of social problems

2016

AbstractUEFA’s Financial Fair Play (FFP) policy represents a severe regulatory intervention in European club football competitions. While potential outcomes of the concept have been thoroughly assessed, there is little research on the genesis and background behind its implementation. The present paper fills this gap by analyzing the discourse in the run-up to the passage of FFP. We focus on interpreted practice and context and argue that the rising indebtedness of clubs and their increasing reliance on benefactors were a necessary but not sufficient requirement. Further ingredients imperative for the successful policy development were claims-making activities by influential actors to secure…

The Great Financial Crisis in Finland and Sweden: The Dynamics of Boom, Bust and Recovery 1985–2000

2009

This paper explores the anatomy of the boom, deep depression and recovery in the Finnish and Swedish economies in the period 1985-2000. These fifteen years are divided into three phases: (1) financial liberalization and the boom and the overheating of 1985-90, (2) the outbreak and spread of the crisis to all sectors of the economy in 1990-92, and (3) the recovery 1993-2000. Each period is analyzed separately.

A mathematical simulation of high temperature induction heating of electroconductive solids

2007

The mathematical model of non-stationary coupled electromagnetic and thermal processes in polarizable and magnetizable axisymmetric electroconductive solids subjected to electromagnetic field generated by external currents is proposed. The processes parameters are connected through heat sources and temperature dependence of material characteristics. The problem is solved by finite element method. The process of induction heating of a finite steel cylinder is considered.

A Photographic study of subcooled flow boiling burnout at high heat flux and velocity

2007

Abstract The present paper reports the results of a visualization study of the burnout in subcooled flow boiling of water, with square cross section annular geometry (formed by a central heater rod contained in a duct characterized by a square cross section). The coolant velocity is in the range 3–10 m/s. High speed movies of flow pattern in subcooled flow boiling of water from the onset of nucleate boiling up to physical burnout of the heater are recorded. From video images (single frames taken with a stroboscope light and an exposure time of 1 μs), the following general behaviour of vapour bubbles was observed: when the rate of bubble generation is increasing, with bubbles growing in the …

The Nukiyama Curve in Water Spray Cooling: its Derivation from Temperature-Time Histories and its Dependence on the Quantities that Characterize Drop…

2007

Abstract Heat transfer from hot aluminium walls to cold water sprays was investigated. The method used was the transient two-side symmetric cooling of a planar aluminium target, previously heated to temperatures of up to 750 K, by twin sprays issuing from full-cone swirl spray nozzles of various gauge. The target’s mid-plane temperature was recorded during the cooling transient by thin-foil K thermocouples and a high-frequency data acquisition system. In order to determine the wall temperature Tw, the wall heat flux q w ″ and the q w ″ - T w heat transfer (Nukiyama) curve, two different approaches were used: the first was based on the solution of an inverse heat conduction problem, the seco…

Stochastic multicriteria evaluation of district heating systems considering the uncertainties

2018

It is of great importance to choose a suitable district heating (DH) system for a specific DH area from the economics, environment and energy (3E) points of view. This is a multicriteria decision making problem, in which the criteria performance values (PVs) and weighting are characterized by uncertain or imprecise information. In this study, seven candidate DH systems are evaluated from the viewpoints of 3E by the stochastic multicriteria acceptability analysis (SMAA) method. SMAA is able to handle the uncertainties of the criteria PVs and the weighting at the same time. These uncertainties are very common and typical in real-life, but in most cases are not treated judiciously or just negl…

An experimental investigation on natural convection of air in a vertical channel

1993

Abstract The free convection of air in a vertical channel is studied experimentally in a laboratory model of height H = 2.6 m and rectangular cross-section b × s , with b = 1.2 m and the channel width s variable. One of the channel walls is heated with a uniform heat flux. Tests are made with different values of channel gap and heating power ( s = 7.5, 12.5, 17 cm; q c = 48–317 W m −2 ). On the basis of the results two empirical formulae are found, giving Nu and Re as functions of Ra and the geometrical parameter s/H ; Nu = 0.9282 Ra 0.2035 (s/H) 0.8972 ; Re = 0.5014 Ra 0.3148 (s/H) 0.418 . The mathematical form of these relationships reproduces other previously published formulae, valid fo…