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Month: May 2008

Procedures for Filling Internal Chemical Scrubber Bottles in the LI-7500, LI-7000, and LI-6400/XT

Procedures for Filling Internal Chemical Scrubber Bottles in the LI-7500, LI-7000, and LI-6400/XT

LI-COR gas analyzers (including the analyzers in the LI-6400/LI-6400XT) require the use of internal chemical scrubbers for keeping absorbing gases out of internal spaces that are part of the optical path. The chemical scrubbing bottles used in these analyzers contain a mixture of Ascarite II and Magnesium Perchlorate; Ascarite II and Magnesium Perchlorate are a good combination for this, since they are voracious scrubbers, and the Magnesium Perchlorate keeps the Ascarite dry. This combination can remain effective for years in…

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Appropriate Sky Conditions for Using the LAI-2000

Appropriate Sky Conditions for Using the LAI-2000

For users of the LAI-2000 Plant Canopy Analyzers, just a reminder that an overcast sky is the best condition in which to use the instrument.

Under cloudy skies, the contribution of scattered radiation is low; when the direct beam of the sun is shining on foliage, scattered radiation is significantly increased. The LAI-2000 optical sensor is filtered to reject radiation above 450 nm, which minimizes the influence of radiation scattered by the foliage. If scattered radiation is present, however, the…

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Is My Soda Lime Working?

Is My Soda Lime Working?

LI-COR often receives support calls relating to the use of soda lime scrubber with the LI-6400/6400XT Portable Photosynthesis Systems, or LI-COR gas analyzers; specifically, many users have trouble scrubbing CO2 from the instrument, even though the soda lime may have come from a new supply. Soda lime typically uses a PH-sensitive Ethyl Violet as an indicator; LI-COR has found that this indicator is often weak, however, so soda lime that has limited scrubbing capacity may not always show a strong…

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LI-6400 Operational Tip – A Sticky Solution for a Tricky Problem

LI-6400 Operational Tip – A Sticky Solution for a Tricky Problem

It can often be difficult to align small blades of grass or needles into position for gas exchange measurements on the LI-6400 standard leaf chamber.

We have found that a simple solution is to use some excess gasket material and cut two small pieces, approximately 0.4 cm wide by 2.0 cm long, and apply them on either side of the lower leaf chamber gasket, as shown below. Apply double-sided tape to these pieces of gasket material. The extra gasket pieces…

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Corrosion Protection for the LI-8100 Connectors

Corrosion Protection for the LI-8100 Connectors

Some users of the LI-8100 Automated Soil CO<sub>2</sub> Flux System have experienced corrosion problems with the pins on the 8100-104 Long-Term Chamber and the 8150-661 Chamber Sensor Interface connectors. The corrosion is due to long-term exposure of the pins to moisture; the simplest solution is to always make sure that the connector is mated to a cable, or to the dust cap, so that moisture can’t enter the connector. Another solution is to apply a small amount of grease (e.g….

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