Gee, that was hard to read...
Wombat, back on suspension, Dr Go forgot to mention that we do have some movement allowed in our front axle of the tank due to it having two strips of heavy rubber in its connection to the chassis, similar to an engine mount.
We felt this would give some damped flex to try and remove some vibration from the whole thing especially since our frame is so stiff.
Something you may want to ask is whether you want to take it to the States one day, then you should seriously think about putting isuspension in.
My gut feeling about the surface is that it will get better in time... there will be some good years and bad years.
rH+
Salt Question
Moderator: DLRA
-
Reverend Hedgash
- Posts: 448
- Joined: Wed Oct 19, 2005 2:19 pm
- Location: Hobart, Tasmania
-
Dr Goggles
- Posts: 1315
- Joined: Tue Jul 05, 2005 11:23 pm
- Location: Right behind you Chief !
Ouch me head hurts
hawkwind racing wrote:[
Ah good Dr but consider the following
In an earlier study on chemical osmosis in clay membranes, a slow dissipation of the osmotically induced hydraulic pressure difference was observed. This nonideal behavior of the clay as a semipermeable membrane was explained by diffusion of salt throughout the clay as a result of the imposed salt concentration gradient. In addition, it was postulated that diffusion of salt causes shrinkage of the electrical double layers of the clay platelets, enhancing flocculation and making the clay more permeable. In the present study, experiments were performed to investigate the flocculation and hydraulic permeability behavior of a bentonite when permeated by gradually increasing salt solutions. The flocculation value was determined by flocculation series tests with NaC1 solutions at different clay suspension densities. The tests show that the Na montmorillonite used has a flocculation value below 0.02 M NaCl. Hydraulic conductivity experiments were conducted using a flexible wall permeameter with NaC1 solutions of different ionic strengths on a clay sample with a thickness of approximately 2 mm. During the experiments, an overburden pressure of 4 bar was applied to prevent swelling. For all NaCl solutions used, both above and below the flocculation value, the hydraulic conductivity stayed constant with values of approximately 2.3.10[-12] m.s[-1]. This implies that flocculation does not take place in the osmotic experiments, and shrinkage of the diffuse part of the electrical double layers of the clay platelets seems to be compensated for by the overburden pressure. Therefore, the dissipation of an osmotically induced hydraulic pressure difference is more likely to be explained by diffusion of salt throughout the clay.
which adds more fuel to the fire
Greek is right...........and I think Greg might be too
That's clay they're talking about and the definition of clay depends on the particle size and the uniformity of the content , the hydraulic pressure is dependent on that size and the affinity of those particles to dissolve , in the above they are talking about how a salt solution intereferes with the expected behaviour( garlic sauce on that mate?).....I dunno if that affects what we're dealing with on the lake ......I'm a long way from when I studied Chemistry and Geology so, shallow as the lake gets I'm rapidly getting out of my depth here but I reckon there is one thing we can trust......we've all seen how pure that surface can be and it gets like that without any outside help...and I'd be surprised if the mud on the surface is such a rare event.......I reckon we can trust the lake to fix itself , hopefully quickly , in the meantime I'm betting that staying wet will help the salt get on top of everything.
The salt lakes in the Kerang area aren't very old , from what I understand they are a result of ancient salt layers dissolving and being brought to the surface by the water table ( irrigation it seems has accelerated this alarmingly) the water evaporates , the salt stays there......bad news when you're growing stuff ( I grew up in the Goulburn Valley). what I'm getting at is that if you give salt some water it'll work it's way to the top sooner rather than later.
Salt is good for racing on , chips and not much else.......
Hey Ben , Emu!................
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
-
David Leikvold
- Posts: 981
- Joined: Mon Apr 16, 2007 11:57 pm
- Location: Brisbane
mud and salt
Doc,
I think you've hit the nail on the head, mud on the lake wouldn't be a rare event. Every time water flowed onto the lake from anywhere else it would bring mud with it. And the salt always rises to the top again, thanks to the famous flocculation. I'm also guessing that the two feet of water in March would really help sink the mud quickly and put a good quantity of saturated solution of salt above it. And the thinner the mud became when the wind blew the water around the lake the more salt would rise through it via osmosis. Rain directly onto the salt is what we'd really like but we'll have to take whatever we get over the next 8 months. As long as the surface is hard and dry who cares if it has dirt stains?
Only 8 months? Oh No! What can I build quickly with no money, no parts and nowhere to build it?!
I think you've hit the nail on the head, mud on the lake wouldn't be a rare event. Every time water flowed onto the lake from anywhere else it would bring mud with it. And the salt always rises to the top again, thanks to the famous flocculation. I'm also guessing that the two feet of water in March would really help sink the mud quickly and put a good quantity of saturated solution of salt above it. And the thinner the mud became when the wind blew the water around the lake the more salt would rise through it via osmosis. Rain directly onto the salt is what we'd really like but we'll have to take whatever we get over the next 8 months. As long as the surface is hard and dry who cares if it has dirt stains?
Only 8 months? Oh No! What can I build quickly with no money, no parts and nowhere to build it?!
Good, Fast, Cheap, pick any two!
-
flyingwombat
- Posts: 17
- Joined: Thu Sep 07, 2006 7:08 pm
-
Reverend Hedgash
- Posts: 448
- Joined: Wed Oct 19, 2005 2:19 pm
- Location: Hobart, Tasmania
-
Dr Goggles
- Posts: 1315
- Joined: Tue Jul 05, 2005 11:23 pm
- Location: Right behind you Chief !
Geek salad
Reverend Hedgash wrote:Science makes sense? You have been away for a while. Ever tried to get your head around a Quantum computer?
Rev.H+
A hydrogen atom rushes into his mates place and says, "Shit, I think I've lost my electron!!"
His mates says, "are you sure?"
He says, " Yes, I'm positive!!"
Get Him Ben !!!!!
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
-
flyingwombat
- Posts: 17
- Joined: Thu Sep 07, 2006 7:08 pm
-
Reverend Hedgash
- Posts: 448
- Joined: Wed Oct 19, 2005 2:19 pm
- Location: Hobart, Tasmania
I don't understand them but I kind of get the gist... amazing things.
Which I think are funnily enough more predictable than the lake surface now.
Had it been 50 years ago I would have said relax, the system has been in simple harmonic motion for hundreds if not thousands of years and minor mud inclusions would have typically been repaired soon after.
With the planet's weather the way it's heading, who knows?
Maybe it is better to put suspension in therefore?
rev.H+
Which I think are funnily enough more predictable than the lake surface now.
Had it been 50 years ago I would have said relax, the system has been in simple harmonic motion for hundreds if not thousands of years and minor mud inclusions would have typically been repaired soon after.
With the planet's weather the way it's heading, who knows?
Maybe it is better to put suspension in therefore?
rev.H+
DLRA Member#412
When we were on the lake first thing in the morning the course looked fantastic. Salt was hard with a few small shallow puddles.
By midday the surface was like a giant slurpy, but you could walk on it and it easily supported the weight of the truck speeding along with a massive rooster tail out the back. If you kicked into the surface it was like beach sand at the edge of the water. Didn't take much to dig down to the mud layer.
I posed the basic question of how salt forms to this lot. Will post any reply for an added flavour to the thread.
http://savethesaltflats.com/wst_page2.html
Regs,
PJQ
Velocity Science Laboratories
By midday the surface was like a giant slurpy, but you could walk on it and it easily supported the weight of the truck speeding along with a massive rooster tail out the back. If you kicked into the surface it was like beach sand at the edge of the water. Didn't take much to dig down to the mud layer.
I posed the basic question of how salt forms to this lot. Will post any reply for an added flavour to the thread.
http://savethesaltflats.com/wst_page2.html
Regs,
PJQ
Velocity Science Laboratories
A response came from the US, after the Save The Salt Flats crew reviewed this thread. There's also a question; does anyone know whether core samples have been taken at any of the lakes?
From Dr. Wally Gwynn.
For what its worth here it is:
Having no knowledge of the Lake Gairdner area, I feel that I may be somewhat out on a limb, but here goes anyway.
It sounds as if the setting for Lake Gairdner is somewhat like that of the Bonneville Salt Flats here in Utah, being relatively similar in size, and with a maximum depth of salt of 4 to 5 feet in places. The difference I see is that there is tributary input to Lake Gairdner from the northwest while there is no direct tributary input to the Bonneville Salt Flats. The salt pan preset at Bonneville, as well as the salt contained in Great Salt Lake and Sevier Lake to the south in Millard County had their origin from Ancient Lake Bonneville which covered an area of some 20,0000 square miles of western Utah and apparent large volumes of salt in Lake Gardner did not have a similar origin. Again, I am not familiar with the geology of the area.
In would assume that dissolved-ion input of salt into Lake Gairdner would be similar to that into Great that is, the salt content would be about the same. Under these conditions, the annual contribution of salt to Lake Gairdner is not all that great in comparison to the volume of salt that is already there. The high tributary input of water into Lake Gairdner during the 2007 period apparently brought large amounts of red sand, silt and clays with it, along with its usual amount of dissolved salts. The major amount of the sand-sized portion of the suspended material would dropped out along the main course of the inflow, followed by the deposition of silts and then clays at the distal extent of the inflow-water’s travels. Therefore, if the presence of clays versus sand and silts has any bearing on raceability, favorable areas might be found.
I would assume that the subsurface brines of Lake Gairdner are similar to those of the Bonneville Salt Flats, that is, they are mainly under saturated or possibly saturated sodium chloride solutions, containing minor amounts of K, Mg, and possibly Ca and SO4. Any fresh water input from the tributaries or from precipitation will enhance the dissolution of the salt that may be precipitated on the playa surface, salt mixed within the red sediments, and to a lesser degree, the salt lying below the red sands, silts, and clays. The salinity of the interstitial brines within the salts below the red insoluble material will also decrease slowly, especially if there is surface movement due to winds moving the brine about the lake. A decrease in interstitial brine in turn, will allow the red sediment material to drop --- slowly, each year or wetting cycle. I suspect that the thickness of the red material will become thicker with time as heavier particles will drop during this process at a faster rate than the finer, claylike particles This is likely a very slow process, and will take many years to form a thick-salt surface that is underlain by the red layer.
As temperatures rise and wind blows across the lake, the brine lying on top of the lake’s surface begins to concentrate. As concentration proceeds, the brine becomes super-saturated with respect to sodium chloride, and hopper crystals begin to form on the surface of the water which, when blown by the wind, sink to the bottom (on top of the red material) thus forming a layer of salt. If conditions favorable for the evaporation continue, a hard layer of salt will be formed over the red material. I am not sure why the salt would be rewetted on a warm day as I do not have sufficient information to make a judgment on this matter. If I were to make a guess, it would be that warming of the salt/brine mixture, increases the volume of the very near surface and shallow intersititial brine which would bring it to the surface, thus making a temporary slushy surface. I am not convinced about the full-moon creating a King-tide – sounds a bit far out as the semi-permeable clay membrane theory that was mentioned.
Sodium chloride will be the first, and probably the only salt that is precipitated. Salts containing K and Mg will not precipitate under these early precipitation conditions but will remain in solution in the under- to saturated interstitial brines. Even if these ions do precipitate under complete desiccation very near the surface, they well constitute a very, very minor part of the salt, and have a very minor affect on the conditions of the salt for racing.
The rough surface condition of the salt (salt ridges) is the result of the salt buckling as the salt forms, and expands as it does so. Also, the conditions of the salt for racing will be different from year to year, if they follow the pattern of the Bonneville Salt Flats. There does not seem to be a constant factor or certain factors that create good or bad racing surfaces. It may be the rate of evaporation, temperature, minute seed crystals such as particles in the air, or a number of other factors. Changes in brine composition, which are very small, do not have a profound affect on the type of salt surface that is laid down.
Question: In areas where 3 to 5 feet of salt have been precipitated (deepest part of the salt) has anyone taken a core of the salt. It may provide some interesting history as to the flooding, dessication, changes in chemistry, etc. that have taken place in the past many, many years that this lake and its contained salt have been in existence.
J.W. Gwynn Ph.D, PG
Posted by PJQ, with thanks to the Save The Salt Flats campaign and the Bonneville Salt Flats Salt Laydown Partnership Project.
From Dr. Wally Gwynn.
For what its worth here it is:
Having no knowledge of the Lake Gairdner area, I feel that I may be somewhat out on a limb, but here goes anyway.
It sounds as if the setting for Lake Gairdner is somewhat like that of the Bonneville Salt Flats here in Utah, being relatively similar in size, and with a maximum depth of salt of 4 to 5 feet in places. The difference I see is that there is tributary input to Lake Gairdner from the northwest while there is no direct tributary input to the Bonneville Salt Flats. The salt pan preset at Bonneville, as well as the salt contained in Great Salt Lake and Sevier Lake to the south in Millard County had their origin from Ancient Lake Bonneville which covered an area of some 20,0000 square miles of western Utah and apparent large volumes of salt in Lake Gardner did not have a similar origin. Again, I am not familiar with the geology of the area.
In would assume that dissolved-ion input of salt into Lake Gairdner would be similar to that into Great that is, the salt content would be about the same. Under these conditions, the annual contribution of salt to Lake Gairdner is not all that great in comparison to the volume of salt that is already there. The high tributary input of water into Lake Gairdner during the 2007 period apparently brought large amounts of red sand, silt and clays with it, along with its usual amount of dissolved salts. The major amount of the sand-sized portion of the suspended material would dropped out along the main course of the inflow, followed by the deposition of silts and then clays at the distal extent of the inflow-water’s travels. Therefore, if the presence of clays versus sand and silts has any bearing on raceability, favorable areas might be found.
I would assume that the subsurface brines of Lake Gairdner are similar to those of the Bonneville Salt Flats, that is, they are mainly under saturated or possibly saturated sodium chloride solutions, containing minor amounts of K, Mg, and possibly Ca and SO4. Any fresh water input from the tributaries or from precipitation will enhance the dissolution of the salt that may be precipitated on the playa surface, salt mixed within the red sediments, and to a lesser degree, the salt lying below the red sands, silts, and clays. The salinity of the interstitial brines within the salts below the red insoluble material will also decrease slowly, especially if there is surface movement due to winds moving the brine about the lake. A decrease in interstitial brine in turn, will allow the red sediment material to drop --- slowly, each year or wetting cycle. I suspect that the thickness of the red material will become thicker with time as heavier particles will drop during this process at a faster rate than the finer, claylike particles This is likely a very slow process, and will take many years to form a thick-salt surface that is underlain by the red layer.
As temperatures rise and wind blows across the lake, the brine lying on top of the lake’s surface begins to concentrate. As concentration proceeds, the brine becomes super-saturated with respect to sodium chloride, and hopper crystals begin to form on the surface of the water which, when blown by the wind, sink to the bottom (on top of the red material) thus forming a layer of salt. If conditions favorable for the evaporation continue, a hard layer of salt will be formed over the red material. I am not sure why the salt would be rewetted on a warm day as I do not have sufficient information to make a judgment on this matter. If I were to make a guess, it would be that warming of the salt/brine mixture, increases the volume of the very near surface and shallow intersititial brine which would bring it to the surface, thus making a temporary slushy surface. I am not convinced about the full-moon creating a King-tide – sounds a bit far out as the semi-permeable clay membrane theory that was mentioned.
Sodium chloride will be the first, and probably the only salt that is precipitated. Salts containing K and Mg will not precipitate under these early precipitation conditions but will remain in solution in the under- to saturated interstitial brines. Even if these ions do precipitate under complete desiccation very near the surface, they well constitute a very, very minor part of the salt, and have a very minor affect on the conditions of the salt for racing.
The rough surface condition of the salt (salt ridges) is the result of the salt buckling as the salt forms, and expands as it does so. Also, the conditions of the salt for racing will be different from year to year, if they follow the pattern of the Bonneville Salt Flats. There does not seem to be a constant factor or certain factors that create good or bad racing surfaces. It may be the rate of evaporation, temperature, minute seed crystals such as particles in the air, or a number of other factors. Changes in brine composition, which are very small, do not have a profound affect on the type of salt surface that is laid down.
Question: In areas where 3 to 5 feet of salt have been precipitated (deepest part of the salt) has anyone taken a core of the salt. It may provide some interesting history as to the flooding, dessication, changes in chemistry, etc. that have taken place in the past many, many years that this lake and its contained salt have been in existence.
J.W. Gwynn Ph.D, PG
Posted by PJQ, with thanks to the Save The Salt Flats campaign and the Bonneville Salt Flats Salt Laydown Partnership Project.
-
Dr Goggles
- Posts: 1315
- Joined: Tue Jul 05, 2005 11:23 pm
- Location: Right behind you Chief !
He's a real Doctor
Hi Wally , thanks for your input .Up until now this has all been guess-work based on a mixture of experience of those who've stood on the lake and quasi-scientific postulation by others (me included) trying to make sense of what we've seen and heard via what we know , and what we think we know (....didn't Donald Rumsfeld have something to say about that???). What you've said confirms what I suspected , that we need water and the fresher it is the better, and the longer the lake stays wet the quicker it will "heal".
However , I'm still curious about what influence tides can have on the water table under the lake .If the water table is close to the surface at any given time surely the conditions that cause "king-tides" in oceans , and large lakes will be noticeable...Gairdner is nearly 100 miles long .If gravity is lower ( caused by the moon ) at one end won't there be a tendency for the water table to rise ,and, if it's near the surface cause "wetting" of the surface?High tide times are listed accurately for coastal areas and bays and vary by hours over hundreds of miles indicating there may be appreciable height differences over say 100 miles ....if the water table under Gairdner was only several inches down then a king tide might pull it up to surface level for a couple of hours.That would explain the track going to slush after being apparently near race ready the day before.What do you think?
Who knows , as I said I'm not a real Doctor , but I'll have a look at it for you
However , I'm still curious about what influence tides can have on the water table under the lake .If the water table is close to the surface at any given time surely the conditions that cause "king-tides" in oceans , and large lakes will be noticeable...Gairdner is nearly 100 miles long .If gravity is lower ( caused by the moon ) at one end won't there be a tendency for the water table to rise ,and, if it's near the surface cause "wetting" of the surface?High tide times are listed accurately for coastal areas and bays and vary by hours over hundreds of miles indicating there may be appreciable height differences over say 100 miles ....if the water table under Gairdner was only several inches down then a king tide might pull it up to surface level for a couple of hours.That would explain the track going to slush after being apparently near race ready the day before.What do you think?
Who knows , as I said I'm not a real Doctor , but I'll have a look at it for you
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
When I first started doing the website, Wayne O'Grady (ex-pres) asked me this very question. And I did some research and thought it to be significant enough to set the dates forspeed week by the cycles of the moon. That's why the moon appears on the speed week page for each up coming event.
I'm not saying that I'm a genius at this but we did it from 1998 (new) till about 2003-4 (last qtr, full), and had good salt each year.
It's also interesting to look at the years that were washed out - 1992 (not sure of date, but it would have been first quarter or full moon), 1997 (not sure of date, but it would have been first quarter or full moon), 2006 (full moon). Also very wet in 1994 (first quarter or full moon) and 2005 (new moon).
For what it's worth 2007 will be a full moon...
I'm not saying that I'm a genius at this but we did it from 1998 (new) till about 2003-4 (last qtr, full), and had good salt each year.
It's also interesting to look at the years that were washed out - 1992 (not sure of date, but it would have been first quarter or full moon), 1997 (not sure of date, but it would have been first quarter or full moon), 2006 (full moon). Also very wet in 1994 (first quarter or full moon) and 2005 (new moon).
For what it's worth 2007 will be a full moon...
Keep the shiney side up........
DLRA WebMaster / Editor
DLRA WebMaster / Editor
Observation from the salt deck on Friday, 2 and Saturday, 3 March. The pattern of "melting" is similar to tide rising:
8:00 AM. Firm but rough surface for the majority of the six miles of the track we travelled. Many ridges, pot holes, and bumps of salt formed over flood debris. Intermittent shallow puddles and soft salt around the three mile marker and timing van (puddles 1 to 2 metres diameter, surface water less than 1cm deep). Air temp between 20 and 25 degrees C.
10:00 AM. Firm surface from start line, softness spreading from the three mile mark. Puddle size increasing to 3 to 5 metres diameter, water 1 to 1.5 cm deep. Air temp 25 to 30 degrees C.
12:00PM. Firm at start line, becoming soft toward one mile mark. Large slush puddles, 20 to 50 metres diameter, open water changed to salt slurry. Air temp above 35 degrees C. Frikkin' hot, some idiot left the cold beer at camp - half an hour's drive away - and the food (but that's not important).
Conditions remained like this for the rest of the day. Cold beer situation rectified immediately. Saturday, first thing, meet was cancelled and we had to clear everything off the salt. "Melting" followed a similar pattern, but we had beer and food with us and went passed the nine mile mark as far as we could for one of those "dissapointed, but how's the serenity" moments.
The Lake Gairdner National Park Management Plan overviews the geology and history of the area. 1.7 MB PDF located here:
http://www.parks.sa.gov.au/publish/grou ... ner_mp.pdf
8:00 AM. Firm but rough surface for the majority of the six miles of the track we travelled. Many ridges, pot holes, and bumps of salt formed over flood debris. Intermittent shallow puddles and soft salt around the three mile marker and timing van (puddles 1 to 2 metres diameter, surface water less than 1cm deep). Air temp between 20 and 25 degrees C.
10:00 AM. Firm surface from start line, softness spreading from the three mile mark. Puddle size increasing to 3 to 5 metres diameter, water 1 to 1.5 cm deep. Air temp 25 to 30 degrees C.
12:00PM. Firm at start line, becoming soft toward one mile mark. Large slush puddles, 20 to 50 metres diameter, open water changed to salt slurry. Air temp above 35 degrees C. Frikkin' hot, some idiot left the cold beer at camp - half an hour's drive away - and the food (but that's not important).
Conditions remained like this for the rest of the day. Cold beer situation rectified immediately. Saturday, first thing, meet was cancelled and we had to clear everything off the salt. "Melting" followed a similar pattern, but we had beer and food with us and went passed the nine mile mark as far as we could for one of those "dissapointed, but how's the serenity" moments.
The Lake Gairdner National Park Management Plan overviews the geology and history of the area. 1.7 MB PDF located here:
http://www.parks.sa.gov.au/publish/grou ... ner_mp.pdf
Regs,
PJQ
Velocity Science Laboratories
PJQ
Velocity Science Laboratories