Time-resolved derivation of heat fluxes from quantitative infrared thermography and its relationship to photoacoustics

1986 ◽  
Vol 64 (9) ◽  
pp. 1190-1194 ◽  
Author(s):  
B. K. Bein
Keyword(s):  
Heat Conduction Equation ◽  
Magnetic Confinement ◽  
Heat Fluxes ◽  
Quantitative Interpretation ◽  
Plasma Power ◽  
Power Losses ◽  
Ir Thermography ◽  
Target Plate ◽  
Time Resolved ◽  
Complementary Techniques

Part of the plasma power losses in magnetic-confinement-based nuclear-fusion devices is deposited on limiters or divertor targets. This part can be deduced quantitatively from time- and space-resolved infrared (IR) surface-temperature measurements at the limiter or divertor targets by solving the heat-conduction equation of the target plate with the help of inversion solutions for the incident heat flux. This quantitative application of IR thermography and photoacoustic or photothermal frequency-dependent measurements are related, complementary techniques. Photoacoustics provides the means to measure the relevant thermal properties, i.e., the value of the effusivity (kρc)1/2 of the target plate, necessary for the quantitative interpretation of the thermographical measurements.

Power Losses in RF Inductor of Ferrite-Free Closed-Loop Inductively-Coupled Low Pressure Mercury Lamps

2020 ◽  
pp. 89-94 ◽  
Author(s):  
Ekaterina V. Lovlya ◽  
Oleg A. Popov
Keyword(s):  
Closed Loop ◽  
Low Pressure ◽  
Mercury Vapour ◽  
Plasma Power ◽  
Power Losses ◽  
Inductive Discharge ◽  
Inductively Coupled ◽  
Radial Inhomogeneity ◽  
Transformer Model ◽  
Rf Inductor

RF inductor power losses of ferrite-free electrode-less low pressure mercury inductively-coupled discharges excited in closed-loop dielectric tube were studied. The modelling was made within the framework of low pressure inductive discharge transformer model for discharge lamps with tubes of 16, 25 and 38 mm inner diam. filled with the mixture of mercury vapour (7.5×10–3 mm Hg) and argon (0.1, 0.3 and 1.0 mm Hg) at RF frequencies of 1, 7; 3.4 and 5.1 MHz and plasma power of (25–500) W. Discharges were excited with the help of the induction coil of 3, 4 and 6 turns placed along the inner perimeter of the closed-loop tube. It was found that the dependence of coil power losses, Pcoil, on the discharge plasma power, Ppl, had the minimum while Pcoil decreased with RF frequency, tube diameter and coil number of turns. The modelling results were found in good qualitative agreement with the experimental data; quantitative discrepancies are believed to be due skin-effect and RF electric field radial inhomogeneity that were not included in discharge modelling.

scholarly journals Nanostructured Metal Hydrides for Hydrogen Storage Studied by In Situ Synchrotron and Neutron Diffraction

2010 ◽  
Vol 1262 ◽  
Author(s):  
Volodymyr Yartys ◽  
Roman Denys ◽  
Jan Petter Maehlen ◽  
Colin J Webb ◽  
Evan MacA Gray ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Exchange ◽  
High Pressures ◽  
Storage Systems ◽  
Time Resolved ◽  
Fast Kinetics ◽  
Al Content ◽  
Unit Cells ◽  
Complementary Techniques

AbstractThis work was focused on studies of the metal hydride materials having a potential in building hydrogen storage systems with high gravimetric and volumetric efficiencies of H storage and formed / decomposed with high rates of hydrogen exchange. In situ diffraction studies of the metal-hydrogen systems were explored as a valuable tool in probing both the mechanism of the phase-structural transformations and their kinetics. Two complementary techniques, namely Neutron Powder Diffraction (NPD) and Synchrotron X-ray diffraction (SR XRD) were utilised. High pressure in situ NPD studies were performed at D2 pressures reaching 1000 bar at the D1B diffractometer accommodated at Institute Laue Langevin, Grenoble. The data of the time resolved in situ SR XRD were collected at the Swiss Norwegian Beam Lines, ESRF, Grenoble in the pressure range up to 50 bar H2 at temperatures 20-400°C.The systems studied by NPD at high pressures included deuterated Al-modified Laves-type C15 ZrFe2-xAlx intermetallics with x = 0.02; 0.04 and 0.20 and the CeNi5-D2 system. D content, hysteresis of H uptake and release, unit cell expansion and stability of the hydrides systematically change with Al content.Deuteration exhibited a very fast kinetics; it resulted in increase of the unit cells volumes reaching 23.5 % for ZrFe1.98Al0.02D2.9(1) and associated with exclusive occupancy of the Zr2(Fe,Al)2 tetrahedra.For CeNi5 deuteration yielded a hexahydride CeNi5D6.2 (20°C, 776 bar D2) and was accompanied by a nearly isotropic volume expansion reaching 30.1% (∆a/a=10.0%; ∆c/c=7.5%). Deuterium atoms fill three different interstitial sites including Ce2Ni2, Ce2Ni3 and Ni4. Significant hysteresis was observed on the first absorption-desorption cycle. This hysteresis decreased on the absorption-desorption cycling.A different approach to the development of H storage systems is based on the hydrides of light elements, first of all the Mg-based ones. These systems were studied by SR XRD. Reactive ball milling in hydrogen (HRBM) allowed synthesis of the nanostructured Mg-based hydrides.The experimental parameters (PH2, T, energy of milling, ball / sample ratio and balls size), significantly influence rate of hydrogenation. The studies confirmed (a) a completeness of hydrogenation of Mg into MgH2; (b) indicated a partial transformation of the originally formed -MgH2 into a metastable -MgH2 (a ratio / was 3/1); (c) yielded the crystallite size for the main hydrogenation product, -MgH2, as close to 10 nm. Influence of the additives to Mg on the structure and hydrogen absorption/desorption properties and cycle behaviour of the composites was established and will be discussed in the paper.

X-Ray Absorption Spectroscopy as an in-situ Tool in Materials Science

1997 ◽  
Vol 502 ◽  
Author(s):  
T. Ressler ◽  
Joe Wong ◽  
W. Metz
Keyword(s):  
Absorption Spectroscopy ◽  
Materials Science ◽  
Ex Situ ◽  
Structural Studies ◽  
Time Resolved ◽  
X Ray ◽  
Complementary Techniques ◽  
X Ray Absorption ◽  
Established Technique

ABSTRACTIn addition to being an established technique for ex-situ structural studies, x-ray absorption spectroscopy (XAS) has recently been realized to be a powerful tool for in-situ time-resolved investigations in materials science. This paper describes two complementary techniques: quick-scanning EXAFS (QEXAFS) and energy-dispersive XAS (DXAS) which offer time resolution in the seconds and milliseconds range, respectively. Formation of a heterogeneous catalyst from a solid-state reaction of a precursor is presented as an example of a time-resolved XAS application.

The effect of sampling rate on interpretation of the temporal characteristics of radiative and convective heating in wildland flames

2013 ◽  
Vol 22 (2) ◽  
pp. 168 ◽  
Author(s):  
David Frankman ◽  
Brent W. Webb ◽  
Bret W. Butler ◽  
Daniel Jimenez ◽  
Michael Harrington
Keyword(s):  
Sampling Rate ◽  
Sampling Frequency ◽  
Heat Fluxes ◽  
Radiative Heating ◽  
Convective Heating ◽  
Moving Window ◽  
Prescribed Burn ◽  
Heating Rates ◽  
Time Resolved ◽  
The Difference

Time-resolved radiative and convective heating measurements were collected on a prescribed burn in coniferous fuels at a sampling frequency of 500 Hz. Evaluation of the data in the time and frequency domain indicate that this sampling rate was sufficient to capture the temporal fluctuations of radiative and convective heating. The convective heating signal contained significantly larger fluctuations in magnitude and frequency than did the radiative heating signal. The data were artificially down-sampled to 100, 50, 10, 5 and 1 Hz to explore the effect of sampling rate on peak heat fluxes, time-averaged heating and integrated heating. Results show that for sampling rates less than 5 Hz the difference between measured and actual peak radiative heating rates can be as great as 24%, and is on the order of 80% for 1-Hz sampling rates. Convective heating showed degradation in the signal for sampling rates less than 100 Hz. Heating rates averaged over a 2-s moving window, as well as integrated radiative and convective heating were insensitive to sampling rate across all ranges explored. The data suggest that peak radiative and convective heating magnitudes cannot be fully temporally resolved for sampling frequencies lower than 20 and 200 Hz.

ElectrodeLess FerriteFree ClosedLoop InductivelyCoupled Fluorescent Lamp

2018 ◽  
pp. 140-142 ◽  
Author(s):  
Oleg A. Popov ◽  
Pavel V. Starshinov ◽  
Victoriya N. Vasina
Keyword(s):  
Closed Loop ◽  
Copper Wire ◽  
Glass Tube ◽  
Luminous Flux ◽  
Induction Coil ◽  
Mercury Vapour ◽  
Plasma Power ◽  
Fluorescent Lamp ◽  
Power Losses ◽  
Pressure Discharge

Electrode-less ferrite-free inductivelycoupled low pressure discharge was excited in the mixture of mercury vapour (~10–2 Torr) and argon (0.1 Torr) at a frequency of 2.0 MHz and lamp RF powers of (150–202) W with the help of a 6turn induction coil. The discharge lamp of rectangular shape (50 cm in length and 7 cm in height) employed a closed-loop glass tube of 30 mm in diam. Tube walls inner surface was coated with three-color phosphor (Тcc = 3100 K, Ra = 80). The induction coil made from silver-coated copper wire (ρw = 2.2x10–3 Ohm/cm) was disposed on the atmospheric side of tube walls, along closed-loop lamp tube perimeter. As plasma power, Ppl, grew from 127W to 180 W, coil power losses practically were unchanged, Pcoil = (25–22) W. Lamp luminous flux, Фv, grew with plasma power from 10430 lm (Ppl =127 W) to 13500 lm (Ppl =180 W), while plasma efficacy, ηpl = Фv/Ppl, decreased from 82 to 75 lm/W, and lamp efficacy ηV = Фv/(Ppl + Pcoil) decreased from 70 to 67 lm/W.

scholarly journals A novel potential nanophototherapeutic based on the assembly of an amphiphilic cationic β-cyclodextrin and an anionic porphyrin

2017 ◽  
Vol 21 (04-06) ◽  
pp. 398-405 ◽  
Author(s):  
Antonino Mazzaglia ◽  
Norberto Micali ◽  
Valentina Villari ◽  
Roberto Zagami ◽  
Rosa Maria Pennisi ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Organic Film ◽  
Time Resolved Fluorescence ◽  
Distribution Profile ◽  
Time Resolved ◽  
Molar Ratios ◽  
Complementary Techniques ◽  
Biological Environment ◽  
Aging Phenomena ◽  
Tumoral Cells

The development of cyclodextrin nanoassemblies as useful carriers for photosensitizer drugs (PS) delivery in biological environment is a topic of increasing interest. In this paper, we present a spectroscopic investigation on a nanosystem based on an amphiphilic cationic β-cyclodextrin derivative (CD-N) and an anionic porphyrin (TPPS). Nanoassemblies were prepared by hydration of an organic film containing the two species. The system was characterized by complementary techniques such as UV-vis, stationary and time-resolved fluorescence, and Dynamic Light Scattering (DLS) at different TPPS/CD-N molar ratios. Time-resolved fluorescence data showed that, at all the investigated molar ratios, TPPS is present both as self-aggregated species and monomers forming supramolecular adducts with CD-N. Moreover, DLS measurements evidenced families of aggregates having hydrodynamic radii ranging between 50 and 350 nm and the size distribution profile depending on the TPPS/CD-N molar ratio. At the highest CD-N concentration, the hydrodynamic radii of the aggregates were nearly the same as those of neat CD-N in the absence of TPPS (50 nm). No aging phenomena were registered, pointing out the high stability of these nanoassemblies in aqueous solution for at least a month. Preliminary studies on the internalization in tumoral cells and subsequent irradiation for PDT application were carried out. The results support the feasibility of these nanoaggregates to promote PS internalization in HeLa cells, inducing cell death upon visible light irradiation.

IR Based Inverse Calculation of Two-Phase Heat Transfer Coefficients in Microgap Channels

2011 ◽  
Author(s):  
Jessica Sheehan ◽  
Avram Bar-Cohen
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Heat Fluxes ◽  
Heated Wall ◽  
Phase Flow ◽  
Ir Thermography ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Two Phase Heat Transfer

IR thermography of the heated wall for the two-phase flow of FC-72 in microgap channels provides explicit evidence of the quality-driven M-shaped variations in the two-phase microgap heat transfer coefficients. Data obtained from a 210μ microgap channel, operated with an FC-72 mass flux of 195 and 780 kg/m2-s and asymmetric heat fluxes of 28 W/cm2 to 35 W/cm2 are presented and discussed.

scholarly journals Advances in Diffraction Studies of Light-Induced Transient Species in Molecular Crystals and Selected Complementary Techniques

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1345
Author(s):  
Krystyna A. Deresz ◽  
Piotr Łaski ◽  
Radosław Kamiński ◽  
Katarzyna N. Jarzembska
Keyword(s):  
Free Electron Lasers ◽  
Transient Species ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Recent Developments ◽  
Complementary Techniques ◽  
X Ray Absorption ◽  
Serial Femtosecond Crystallography ◽  
Major Emphasis

The review provides a summary of the current methods of tracing photoexcitation processes and structural dynamics in the solid state, putting major emphasis on the X-ray diffraction techniques (time-resolved Laue diffraction on synchrotron sources and time-resolved serial femtosecond crystallography on X-ray free-electron lasers). The recent developments and nowadays experimental possibilities in the field are discussed along with the data processing and analysis approaches, and illustrated with some striking literature examples of the respective successful studies. Selected complementary methods, such as ultrafast electron diffraction or time-resolved X-ray absorption spectroscopy, are briefly presented.

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