xFOCE/swFOCE 
Concept Design Review
mon 14 may 2012

Kline (Scripps)
Fiorenza Micheli (Hopkins )
woodson (COS/Stanford)
Helen OBrien (UCSC)
Adina Paytan (UCSC biogeochemist)
Chris Harrold (MBA dir conservation, research)

gomes, salamy, shane, kirkwood
matsumoto, oreilly, kecy, maughan
barry, walz, mellinger, erickson
au, birch, scholfield, sherman, edgington, roman
chaffey

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# Notes
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[Peltzer]

[Kirkwood]
large offsets at high currents
paytan - balance between pH flushing too fast or too slow

considered reservoir for equilibration - time to equilibrate (yes, but doesn't equilibrate until mixed w/ other water). but still needs time to eq w/ 
else must flush entire system if using exactly desired pH.

Flow speed fixed? it's variable. we chose 10 cm/s
10 is low for shallow sys.
big recirc needed for 50 (50 would be better), mostly just an issue of
CO2 use. internal paddle for surge w/o water exchg

swFOCE 3 exp/3 ctrl xFOCE 1/1

are flow meters mechcanical (Elec/Mag - no moving parts, no flow obstruction)

how difficult to add pCO2 - they are slow, in situ ones 
SAMI 1 sample/15 min - better than discrete sample diving
looked at Quantros - new things coming out
trying to min diving 1/2wks
At heron, dove daily, now working on automated sampling 
diurnal changes if there's a lot of activity
70% work over 8 mo was processesing discrete samples.
take samples away from unit.
 
want to char carbonate chem in control and and insisde treatment and ambient
hard prob to deal w/ in terms of people required

how to manage backflow - must sample reference far enough away from chambers

could use osmo sample that collects slowly, and then sample daily, weekly, etc.

could sample background conveniently from intakes to ESW, but can't get chamber, control samples that way

this is important to carbonate chemistry
night sampling is important - mylar bags w/ fixative, solenoids.

Can add to FOCE, but not core

cleaning needed daily (chamber and instruments) - 20 min daily, 
longer if you let it go.
Also, scrubbing chamber makes biofouling worse 

permitting...

[Headley]
paytan - would be good to have place to go to have someone build one for groups w/ minimal engr experience
kline - can do meetings/workshops with other xFOCE users (engrs, sci users w. experience) prior to your own project - take advantage of user community

roman - to mitigate mult software platforms, make SN software more like firmware - parameterized - so that it doesn't need to be touched often.

mellinger -
- why would you suggest making a system w/o GF detection/isolation 
- are there packaging standards for small processors, or is there lots of bolted-together pieces?

au - what custom hardware does the user have to implement
- what is target for how much the user would implement - to what degree do they need design custom HW? (idea is to make designs and doc that users can use to make basic foce w/o going under the hood)

au- how do you get around not useing GF on isolated (moored system) for safety? May mean you have to add custom HW/SW to make safe and reliable... cpFOCE used 12V system, so no human danger

suggestion for web site:...

[Shane]
kline 
- Acid bath easier for cleaning
- Don't scrub the chamber - creates more nucleation sites for biofouling

- impeller bilge pumps (aquarium type) clogged w/ sand, didn't work well
paytan - longer RV types may be better than other cartridge types...

CO2 scrubbing - filters remove particulates, leaving CO2 and Nitrogen(?).
how much is it necessary to clean it - how pure the CO2 needed?
what about trace organics messing up experiment?

1xD size tank lasted 1 month on Heron
e.g. antarctic has diesel, but shipping CO2 expensive

20 cylinders/day, depending on scale, size of chamber, etc.

for web site: 
decision tree: chamber size, CO2, pump size

[Kecy]
chaffey - fundamental requirement is that failure of one device shouldn't bring down whole experiment.

with xFOCE, there are minimal instruments, so losing one thing means you have to stop experiment and fix it.

e.g. if GF in one instrument, turn off all three

paytan - if you've been running for a long time and know relation between T and pH, would want to keep going, even w/o pH e.g., then assume variability post-experiment.

but you can't close the loop and control pH

it is valuable to know which sensor is bad...

that's why we have spares - replace it w/ good unit.
What is field replaceable unit size?
can diver go out and do the swap?

paytan - but would not want to stop CO2 flow and keep running.
For long term study, things will fail...
can you put it in steady state, and keep going.

more redundancy 
don't eliminate option to have high reliability possibility

even if you know GF to a sensor, you still can't tell whether 

Good idea to have limp mode...
argues for having expansion room at Gateway level to 
Different instruments have diff cal periods - so may be disruptive to re cal 

MTBF, service intervals are different, 
if nodes are low cost, then can increase numbers - e.g. use one node for one instrument...but GW has to be able to expand

failure is different from scheduled maint
in failure, must bring back both sides.

what is power for wago? ~50-70W
power for pumps overwhelms computer power at heron

did we consider using DSL for swFOCE?
runs over copper, long distances, big savings in connectors
fiber is less user friendly. high speed and robust.
more info in appendices.

how do you leave in option for video?
have bandwidth - 
video on each chamber? no reqmt
power budget for pumps, circulators?
most power was to accelerate
what pumps for ESW inject? peristalt 25W, gravity

does flow change w/ tide if using gravity?
can modulate valve opening time on shore.

need 2 atm head CO2 on ESW gen

[Salamy]
is it valuable to monitor bus voltages, gfs, etc.
also, we add lots of alarms, that at then ignored...is this helpful?

paytan - don't usually monitor these, but maybe would be useful(?)

what is model for science use?
at first Jim, up to scientists to arbitrate use between COS, HMS, etc. 

how long will it run, maintenance handoff, 
primary sponsors HMS, MBARI - may be only users for a while.
once it's up and running (a lot of effort), often good to get parallel data from many users.  

MBARI and HMS primary users, would be great to involve collaborators to extent possible.

could, e.g. pass water to another chamber for another experiment.

need a data integration system w/ single timeline to know how observations link together - to be able to see measurements on a common timeline - including water samples, failures, cals, etc.

e.g. on GUI to be able to put them together, CANON/DSS style
it would streamline data analysis.
the more integrated it is, the faster it is to get useful information out of the system.

record keeping, daily reports (automated): system 
may want to log data faster than you have summary reports for.
How fast is fast enough ondiff parameters - community recommendations for pH? CTD?...

should sample with divers first to see if there is a signal?
how fast are things changing? sample hourly to establish diurnal patterns?
background signal could change 
worth doing manual water samples initially,
in chamber, things may change more slowly.

how easy is it to take phys sample - mesh bags, carbiner
8x50ml took about 10 min.
5 syrnge....can put port in side

Carbonate chem takes a lot of time