Antarctic penguins ; a study of their social habits, by Dr. G. Murray Levick

Levick, G. Murray

doi:10.5962/bhl.title.31689

Cited by 4 publications

(3 citation statements)

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“…If, as in this case, a chemical reaction is studied, the emissivity of the sample will change over time in an unknown and unpredictable fashion. Techniques such as laser-absorption radiation thermometry, which allow one to measure the temperature of a gray body without knowing its emissivity, may be suitable in the future, although more development effort is necessary.…”

Section: Discussionmentioning

confidence: 99%

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR

Jones¹,

Winter²,

Florian³

et al. 2005

J. Phys. Chem. B

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The kinetics of the reaction of batches of powdered quartz and sodium carbonate was studied by in situ (23)Na nuclear magnetic resonance (NMR) spectroscopy using a laser-heated probe. We show for the first time that the technique allows one to study solid-state reactions at high temperatures with good time resolution and without the risk of quenching artifacts. The reaction is controlled by solid-state Na(+) diffusion across the grain interface. Independent of the batch composition, the first reaction product is crystalline sodium metasilicate, Na(2)SiO(3), even if the temperature is high enough for much of the composition space between silica and metasilicate to be above the equilibrium liquidus. Fast Na(+) diffusion allows the reaction front to cross the grain interface and form the solid product before liquid intermediate equilibrium products can be formed. This purely solid-state reaction slows down as the thickness of the interface increases; the reaction is more deceleratory than published models suggest. If excess quartz is present, it reacts in a second step involving a liquid film wetting the excess grains. Once this reaction has started, it pulls the reaction into the thermodynamic regime, which leads to an increase even in the rate of the first step leading to intermediate solid metasilicate.

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Section: Discussionmentioning

confidence: 99%

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR

Jones¹,

Winter²,

Florian³

et al. 2005

J. Phys. Chem. B

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“…LART uses two additional low-power infrared lasers at different wavelengths as a source of small surface temperature fluctuations, which are measured pyrometrically at these two wavelengths [22]. The results from the two measurements are divided by each other, and the emissivity cancels out of the equation.…”

Section: Discussionmentioning

confidence: 99%

Laser-Heated High-Temperature NMR: A Time-Resolution Study

et al. 2007

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The time resolution achievable in in-situ high-temperature nuclear magnetic resonance (NMR) experiments is investigated using laser heating of refractory materials. Three case studies using 27 Al in alumina nano-particles, 29 Si in silicon carbide and 23 Na in a glass-forming mixture of sodium carbonate and quartz have been conducted to distinguish the cases of (a) a fast-relaxing, high natural abundance nucleus, (b) a probe nucleus with low abundance and low spin-lattice relaxation rate, and (c) a complex and changing system of industrial relevance. The most suitable nucleus for in-situ high-temperature studies is one with high abundance but slow relaxation because the differential relaxation time between hot and cold parts of the sample effectively removes the signal from the cold material.

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“…Bundles are mostly used for light transfer in bifurcated bundles, [20][21][22][23][24] imaging, 25,26 and fluorescence. [27][28][29][30][31] Interference filters typically have higher throughput than diffraction gratings; however, the throughput advantage may be lost because the light power is split into several channels by the splitter. Secondly, if intensity drift is not proportional in the separate optical channels, the splitter may negate the advantages of reference intensity corrections.…”

Section: Introductionmentioning

confidence: 99%

Comparison between Two Detection Systems for Fiber-Optic Chemical Sensor Applications

Yuan

DeGrandpre

2006

Appl Spectrosc

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Two optical detection system designs are compared for fiber-optic chemical sensor applications. A single grating spectrograph with fiber-optic input and photodiodes at three different wavelengths is compared to 1x3 fiber-optic splitters and photodiode detectors with integrated interference filters. The splitters are used to direct the optical power to the filter photodiodes. Three types of 1x3 commercially available splitters were tested: a 400 microm fused glass fiber-optic coupler, a 1000 microm fused plastic fiber-optic coupler, and a 1000 microm glass fiber-optic bundle. This study finds that the fiber-splitter-based detection systems have similar stray light, signal-to-noise ratio, and long-term absorbance stability compared to the spectrograph detection system with a modest improvement in spectral resolution (from approximately 12 nm to approximately 6 nm). It is also much smaller in size and lower in cost. Applications of the two systems in a colorimetric CO2 partial pressure sensor are compared and similar accuracy and precision are achieved.

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Antarctic penguins ; a study of their social habits, by Dr. G. Murray Levick

Cited by 4 publications

References 0 publications

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR

Laser-Heated High-Temperature NMR: A Time-Resolution Study

Comparison between Two Detection Systems for Fiber-Optic Chemical Sensor Applications

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Antarctic penguins ; a study of their social habits, by Dr. G. Murray Levick

Cited by 4 publications

References 0 publications

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ 23Na NMR

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ 23Na NMR

Laser-Heated High-Temperature NMR: A Time-Resolution Study

Comparison between Two Detection Systems for Fiber-Optic Chemical Sensor Applications

Contact Info

Product

Resources

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Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR

Tracing the Reactive Melting of Glass-Forming Silicate Batches by In Situ ²³Na NMR