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arc

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Posts posted by arc

  1. To add to Acme's good analysis;

     

    The two metals also have quite different coefficients of thermal expansion between them. And when exposed to cycles of heating and cooling, such as through friction from braking during deceleration, and forces from dynamic loading during cornering for example, these changes can allow moisture from the weather and condensation from thermal cycling to penetrate more easily between the dissimilar materials. This can accelerate the galvanic corrosion, or on their own, bring enough microscopic foreign material into the part's contact surface area to make them difficult to remove years later.

     

    The greater the difference in the coefficient the greater the space for water and foreign material to occupy. So, if your part's contact areas are still smooth and do not have the visible corrosion from electrolysis it is probably the thermal cycling alone and/or foreign material.

     

    Some manufactures actually preheat some parts before the assemblies are combined and use negative thermal expansion to hold the parts together. This, of course would require you to heat the proper part to disassemble the components.

     

    https://en.wikipedia.org/wiki/Thermal_expansion

     

    "The coefficient of thermal expansion describes how the size of an object changes with a change in temperature. Specifically, it measures the fractional change in size per degree change in temperature at a constant pressure. Several types of coefficients have been developed: volumetric, area, and linear. Which is used depends on the particular application and which dimensions are considered important. For solids, one might only be concerned with the change along a length, or over some area."

     

    post-88603-0-14765600-1483504215.png

     

  2. !

    Moderator Note

    Suddenly, everyone focused a bit more on the topic, and the thread was saved! :lol:

     

     

    I know that article and it's not evidence.

    When dogs (or other carnivorous animals) notice some improvement because of eating grass or plants then they might eat it often if they like the taste or only when they feel sick, when they don't like the taste. My dog doesn't like the taste so he only eats it when he feels sick. I tried other green vegetables/plants but he doesn't like the taste...even when I mix it in meat.

     

    When a dog only gets BARF, https://en.wikipedia.org/wiki/Raw_feeding

    his poo can be very hard. (it's called concrete poo)

    This happens when your dog gets to much bones or if his digestive system is not 'strong' enough. You can make the poo become less hard and increase in mass by giving vegetable/plants porridge. The more fiber/cellulose in the plants/vegetables, the softer and bigger the poo becomes.

     

    This is a pubmed about the Effects of fiber on digestibility and transit time in dogs.

    "Fecal weight and water increased linearly with added fiber"

    "Intestinal transit time decreased from a mean of 37.4 to 28.7 hours with added fiber. "

    https://www.ncbi.nlm.nih.gov/pubmed/6286909

     

    A swing . . . . . . . . . . . and a miss. :doh:

  3.  

     

    Might evolve into a new species, and going extinct in that case is not a given; there could be a branch-off which leaves Homo sapiens existing.

     

    By what we see almost every day it is obvious that we are moving steadily towards the future of the gradual blurring of what we now consider human and what will later be considered the increasingly technologically enhanced version of Homo sapiens. We may very well become extinct and evolve simultaneously. Who will decide this and where they draw that line would be interesting to know.

     

    But to be sure though, this time we are choosing the direction of our own evolution.

  4. I have an acrylic emulsion based caulk with lots of various fillers and actives. Any suggestions for additives that would improve the adhesion of this caulk to natural rubber? The adhesion is not bad but the rubber gets compressed and I am looking for improvements in adhesion to the substrate under stress.

     

    There are probably industrial solutions out there off the shelf, but I wouldn't mind knowing what the chemistry actually is rather than buying a trade named additive. Keying up the surface of the substrate before application might improve adhesion too due to extra surface area to bond to, but I want a securer bond.

     

    I can envisage different functionality on the polymer backbone changing the adhesion properties, but this isn't an option in this case. (although I could use a different polymer system - maybe an epoxy would bond better?). What would be an easy fix would be an additive or a chemical that would improve the adhesion of this acrylic to natural rubber.

     

    Thanks.

     

    P.

     

     

    This site may have some useful information.

     

    http://www.masterbond.com/resources/surface-preparation-for-rubbers

    The three most common techniques used for surface treating rubber substrates are:

    1. Trichloroethylene Solvent: Degrease the rubber substrate as mentioned above using trichloroethylene solvent.
    2. Modified Bleach Solution: Prepare the modified bleach solution by pouring cold DI water (1 liter) into a clean container made of plastics, glass or similar inert ware. While stirring the water, add concentrated hydrochloric acid (5 ml) in a slow steady stream. Then add household bleach (30 ml), stirring it thoroughly into the diluted acid. Immerse the rubber substrate in modified bleach solution for 1-3 minutes at room temperature. Following that, rinse it in cold DI water, followed by a rinse in hot DI water. Finally dry the substrate in hot air.
    3. Sulfuric Acid Solution: Immerse the rubber substrate in concentrated sulfuric acid for 2-10 minutes. Following that, rinse it in cold DI water, followed by a rinse in hot DI water. Finally dry the substrate in hot air.

    post-88603-0-62221100-1481831745_thumb.png

  5. Just a reminder, not meaning to distract from the OP, but, whether you use wind, water, coal, gas or any other examples you are actually using solar energy. It's just each one has a specific time delay specific to its derivative process to and from the solar source. Fossil fuel being probably the oldest (photo synthesis) (or would it be nuclear from some primordial star?), and photo voltaic being the most instantaneous source with the others assuming their respective positions along their own mechanistic timeline.

  6. 1. Extensive presence of liquid water.

    2. Or, to put it another way, Goldilocks zone conditions.

    3. Salinity, pH, fugacity, etc.

    4. Gravitational acceleration

    5. Solar spectrum

    6. Atmospheric composition

    7. Atmospheric motion

    8. Ocean currents

    9. Etc.

     

    . . . . and Plate Tectonics. Ophiolite, how could you leave this one out? ^_^

  7. Imagine that you have a rope which is 24 cm long.

     

    If you make a perfect square from this rope (each side is 6 cm) then the area becomes 6 x 6 = 36 cm^2.

    If you make a perfect triangle (each side is 8 cm) from the same rope, then the area becomes (768)^0.5 which is approx. 28 cm^2

     

    So the length of your border is always the same, but this same border length surrounds different amount of area for different shapes.

     

    The border length is the same, but the area size is different.

     

    I am not asking mathematical explanation, but I am searching for the logical explanation. What is the logic behind this? Difficult to understand the logic.

     

    Nature always moves to the lowest energy state. If a volume of water is placed in a zero gravity environment it forms a perfect sphere which is the lowest energy state it can attain. You are observing a two dimensional abstract example of this principle, and can observe its graduated numerical representations by manipulating the boundary's shape. As the volume of the shape increases the surface ratio of angled corners will decrease in proportion. Think of a star shape utilizing as many corners and sides as possible.

     

    Pressure containment and structural load bearing designs naturally take advantage of this principal so we all rather sense this in an almost subconscious expectation of the world around us.

     

     

    Edited for clarity.

  8. You are likely seeing the result of the installation of an EFIS system on the exterior of a building.

     

    https://en.wikipedia.org/wiki/Exterior_insulation_finishing_system

     

    This video below is not an EFIS installation but it does show how much of the polystyrene foam is lost with just a small amount of processing. Normally the flat polystyrene panels are screwed to the building's exterior and then covered with a mesh on to which a thin layer of stucco is applied. Normally the panels need to be cut to fit around window and door openings, and when smaller pieces are needed at corners and other transitions. The mess is made when these panels are cut to size, usually with just a hand held carpenters saw.

     

     

    When they want the buildings to have architectural accents like enormous bull-nose cornices they will stack and layer large dimensional polystyrene foam pieces together and then sand them to shape with large rasp sanding boards.

     

    post-88603-0-30723800-1481692961.jpeg

     

    I have seen at one construction site what looked like a snow storm as a dozen workers sanded off a 1/3 to a 1/2 of the material to gain the desired shape. The stuff was blowing down the street and piling up as drifts against curbs and buildings. These were mostly the tiny round foam components that make up the bulk material. The debris in the video is even finer and will stay airborne for great distances.

     

    Much of this mess can be eliminated if architects avoid custom shapes and use factory available pieces.

  9. OK, that is a bit to think about. If the egg actually got into the vacuum then that would be the end of it (the vacuum I mean).

     

    You can buy high efficiency bags for that vacuum, so all you would need to clean is the hose. But you could also just replace the hose, they are not very expensive.

    post-88603-0-41947500-1481444078.jpg

     

    And you can find the eggs you cannot see by mounting a mirror (old car mirror) on the end of the pipe to see downward. You can add a 30 or 45 degree coupler to the end to aim downward, just make sure the pipe size is large enough to accommodate an angled coupler that an egg will fit through. Or just go for breaking and sucking up the remains.

  10. If all I wanted to do is break the eggs I would get one of these air powered pellet rifles. It has a flashlight and laser to pinpoint the target.

    http://www.sportsmansguide.com/product/index/gamo-big-cat-varmint-air-rifle-with-scope-laser-light-combo?a=444174

    $144.90 0.177 cal · 1000 fps

     

    post-88603-0-61167000-1481417854_thumb.gif

     

    post-88603-0-51694700-1481417896_thumb.jpg

     

     

    But I myself would just suck them up with a powerful shop-vac. This is the one I have and I really like it. You will probably need one with around 5 HP for this application.

     

    https://www.amazon.com/gp/product/B0023EY052/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=toolconsult-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B0023EY052&linkId=3faf6b9042d7e535f08b577e35480a80

     

    post-88603-0-79407700-1481418676.jpg

     

    Get some schedule 20 white PVC plastic pipe with an inside measurement as close to the egg's diameter as possible.

     

    post-88603-0-01618300-1481419180.jpeg

     

    And connect them together with some PVC couplers;

     

    post-88603-0-41792500-1481419187.jpg

     

    Buy as many 3 meter long pieces of pipe as required and cut them as needed. They are quite inexpensive.

     

    You can use PVC glue to connect the pipes together but I would recommend just duct taping them, or better yet, just use some very short screws that won't extend inside of the pipe's interior to stop or break the eggs as they come through.

     

    You really want to be able to adjust the pipe length quickly and easily so you can move to the different locations without to much trouble and still be as close to the access opening as possible to see what's going on. With the vacuum turned off you can slide the pipe end up to the egg and the hit the switch to suck-up the egg, then switch it off before moving to the next target. You can mount a flashlight to the pipe or just get a powerful spot light and/or someone to point it at the target. It's hard to see into a dark area when you are outside in the bright daylight, it is much easier to do this at dusk or nighttime.

     

    BTW I have been removing wasp nests around the homestead with this setup for years. I use the 12.5 mm pipe size and just put the pipe end near where they come and go out of the nest. After a while there are not any of them left outside the nest and all the ones that have tried to get out are gone also. I then just shoot a little pesticide it the nest opening and the job is done. Empty the vacuum a few days after, they are always dead or near to it. 8 plus hours in a swirling vacuum vortex takes all the fight out of them.

  11. post-88603-0-24528600-1481070387.jpg

     

    The problem with this design is it will steer to the side of its leading edge. It is basically a rudder moving in the direction of least resistance. Old horse drawn designs were commonly home built and triangular to eliminate any uneven side loading. But they would/could only do that for the first run-through, so they had to be made wide enough to clear the desired width within one run. Deeper snow would of course be handled by repeatedly covering the same path as many times as necessary.

     

    Another solution is to have a side board along the same side as that of the plow's leading edge to counter the side force that the singe blade design produces. This is a nice feature because its length can be adjusted to compensate for the snow's density and the blade's attack angle and the depth of the blade's cut (bite).

     

    A draw beam centered and rigidly attached to the blade would give the best control and eliminate the "shimmy", or side to side yaw that would occur with that bridle arrangement. The draw beams length can be quite long, to not only add the mentioned stabilization but to also create a down force on the blade edge. This can be further controlled by a means of an height adjustable wheel or ski towards the front of the draw beam to optimize the blade's pitch. The draw beam also provides a ideal support structure for the side board that needs to run parallel to the beam by its attachment means, some vertical adjustment would be desirable here also.

     

    At this point it would take two operators; one to operate the winch and one to handle the snow plow. Moving the winch to the draw beam would eliminate one of these people and switching to a gas engine would eliminate the power cord.

     

    At this point a machine such as the one suggested by Mordred would be the best choice. This is because the snow plow is a cumbersome solution at best, that really only work well when on wheeled or tracked equipment with adequate traction.

     

     

    And just for fun;

     

    http://www.snowplowtalk.com/#sthash.dAVCq3Md.dpbs

    A company based in North Carolina by the name of SuperDroid Robots has developed a robot that would plow snow for you while you sit back and relax.

    post-88603-0-80361400-1481075749_thumb.jpg

    The robot will cost you about $8,500 and will prove most useful if the snow level lies between 2-6 inches. The robot is a six wheeler and comes with a plough blade which is 52” in length and works pneumatically. The robot can be controlled via tablet or your desktop PC. It weighs about 181.82 pounds and is capable of running for two hours on two car batteries. However, there is room for more batteries and hence, more work time. The RoboPlow will actually clear your driveway of snow while you have breakfast. So watch out snow plow manufacturers, because the winter is no match for RoboPlow.

  12. The contents of the egg holds the potential for the new species, which at the point of being laid is not a chicken yet but will be.

     

    Is a chicken egg an egg that hatches into a chicken, or an egg that is laid by a chicken?

     

    The definition you use gives you the answer.

     

    If a chicken lays an egg in the forest and no one is there to hear it . . . . . . .

  13. Saying science ridicules chi is like saying we ridicule unicorns. That's' nonsense, we can't laugh at a unicorn; they are not there to laugh at.

     

    Until you can do that I strongly urge you not to come back; (BTW you are likely to get ridiculed if you do.)

     

    Especially if you are wearing one of these;

     

    post-88603-0-85961800-1480894327_thumb.jpg

  14. Thanks, arc.

     

    Not a soft enough soil to probe. County topographical maps show no sink holes in the area. In three days I will have utilities demarked and a friend will come with digging equipment to explore. Will try to add a picture later.

     

    Your welcome. I look forward to seeing what you find. Digging a hole in the ground and looking at the night sky with a telescope are the only two "Time Machines" that anyone can own and operate. ^_^

  15. I've got a few questions;

     

    1. How far is the sink hole from the street.

    2. Does the street have curbs and storm drains.

    3. Is this neighborhood older than thirty years.

     

    Years ago I purchased a fixer-upper built in 1920 that had been hooked up to the district sewer in the late 1950's or early 60's. The line ran down the side of the house from the street. The surface above it had been a graveled driveway before and after the installation of the line. The driveway had been slowly raised with added fill material over the years by the previous owner and I had assumed it was to prevent the surface water from the street coming onto the driveway. In preparation for paving the driveway I remove around 30 cm of material and continued to drive on the area.

     

    One day I pulled onto the driveway in my Toyota Corolla, pressed on the brakes and felt the whole left side of the car drop to the ground as if the wheels had fallen off. I had collapsed the surface into the old ditch. I had just enough clearance to back out and examine the results. I could see where the original fill material had settled approximately 30cm, leaving a dome shaped cavity running the entire length.

     

    Some properties have easements that the local water dept use. Some of these service lines are quite large. The ditches are usually back filled with crushed rock to inhibit corrosion and prevent post burial settling of the over laying and under laying fill material. Fill material will settle even after the compaction done during the installation work. Older lines did not get as good of compaction as the more recent installations do. Mechanical and hydraulic machinery have greatly improved the process.

     

    Its possible these cavities could provide a place for surface materials to migrate into over extended periods of time. I think its time to do some testing of the site. Can you probe the area with a small diameter rod to see if a hollow area exists there or adjacent to it?

  16. I viewed both videos, that first one reminds me of the standard, and sadly effective, Scientology propaganda. Those testimonials that start around 18:00 are spot on of Scientologist fair. "OOOW, I'm so much more aware now!" . . . . "I feel so much more intelligent!". . . . Blah Blah Blah.

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