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Sequoia is the sole manufacturer of the LISST series laser
sediment/particle/bubble/droplet sensing instruments, compliant with the ISO-13320-1 standard. Some of these
instruments deliver the optical volume scattering function (VSF) of interest to optical oceanographers.
The LISST series includes submersible and non-submersible
instruments. All employ the small-angle forward scattering principle,
also called low-angle laser scattering or laser diffraction.
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| | | | | The submersible series includes:
- LISST-100X
- LISST-25X
- LISST-SL
- LISST-Deep
- LISST-STX
- LISST-HOLO
| |  | | The LISST-100X is Sequoia's
workhorse. It delivers the size distribution of suspended sediment in
32 logarithmically spaced size classes. Different models of this
instrument cover different range of sizes.
The LISST-100X can be powered via the internal battery (non-rechargeable) for autonomous deployments or externally via a communication cable for real-time display of the size distribution.
A range of accessories exists for the LISST-100X. Used together with these accessories it is possible to use the instrument as a laboratory particle size analyzer. | | | | | | |  | | The LISST-25X is a patented
derivative product. It delivers the suspended sediment concentration
and mean size in two size classes (2.5-63 and 63-500 microns).
Data are stored internally on the instrument, and up to 6000 measurements can be stored on the instrument.
Some accessories exists
for the LISST-25X. | | | | | | |  | | The LISST-SL is a stream-lined
isokinetic version of the LISST-100X developed for river sediment
monitoring. The instrument senses the river current velocity using a
pitot tube and adjusts intake velocity to
match. The river water is thus pumped through the instrument at the
same speed as the water flowing around the instrument, making the
sampling isokinetic.
Optics
and electronics are enclosed and the data are transmitted via a USGS
B-reel to a topside control box containing the batteries. Data are
stored on the topside box and displayed in real-time mode on a touch
panel display. Please note that a USGS B-reel is necessary to operate the LISST-SL. (What is a USGS B-Reel?)
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| | LISST-Deep was a deep-sea version of the LISST-100X, capable of operations to 6000 m.
The LISST-Deep was discontinued in 2009, to be replaced with a deep-sea version of the LISST-HOLO.
| | | | | | |  | | The LISST-STX is an extended
version of the LISST-100X, with an added Settling Tube (ST stands for
Settling Tube). This instrument is designed to perform submerged
settling experiments to obtain settling velocities of 8 size
classes.
With the settling column removed, the LISST-STX may be
used as a -100X, but with less than optimal flow through the sample
volume.
When
used for settling velocity estimates, the LISST-STX must be securely
mounted on a bed frame or a tripod, otherwise the instrument will not
deliver reliable data. | | | | | | |  | | The LISST-HOLO is a holographic camera currently under development by Sequoia (manufactured under a license from Plymouth University, UK).
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| This series includes:
- LISST-Portable
- LISST-Streamside
- LISST-Infinite
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LISST-Portable is the worlds first and only battery powered portable laser particle sizer. Weighing in at less than 5 kgs (10 lbs), it is truly portable and can easily be carried to a sampling site (river, dam, stream, runoff) or simply used in the laboratory as a stand-alone particle sizers.
The LISST-Portable is equipped with a touch-panel display for easy programming and display of data. All data-processing is performed on board the instrument so no post-processing is necessary. The processed data are offloaded as an ASCII file for easy display in Excel, MiniTab etc. | | | | | | |  | | The LISST-StreamSide is designed for long-term monitoring applications such as stormwater, and river monitoring. Like the LISST-Portable it is equipped with a touch panel display for easy programming and display of sampling status. Data are processed on board and offloaded as ASCII files. The LISST-StreamSide incorporates and automatic cleaning procedure where the optical surfaces are flushed with clean water at a user-defined interval. Subsequently a clean water background measurement is taken.
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| | | | | The LISST-Infinite is an auto-dilution instrument designed for use in monitoring river sediments for run-of-river hydro power plants. | | | | | | | | | | For further information, use the links at the top of the page or contact us.
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2010 NWQMC 7th Nat'l Monitoring Conference
Denver, CO, 25-29 April 2010, booth 304
USGS Nat'l Data Conference
Omaha, NB, 11-13 May 2010
Joint 9th FIS and 4th HMC Conferences
Las Vegas, NV, 27-20 June 2010, booth 207
9th annual StormCon
San Antonio, TX, 2-4 August 2010, booth 421
Ocean Optics XX
Anchorage, AK, 25 September - 1 October 2010
CASQA 6th annual conference
CA, 1-3 Novemb | | |
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