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Although your court is technically still cracked, the filled cracks are hidden beneath our repair and then covered over completely with color-coating materials. Although it will not prevent cracks from developing elsewhere on the court, or prevent cracks from growing in length out beyond the repair, the ARMOR Crack Repair System successfully keeps repaired structural cracks from reappearing on the surface. There are some limitations and not all cracks are repairable with our product, so talk to your contractor about your specific court.
no more cracks in the armour
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# of Layers Over Crack: The ARMOR Crack Repair System utilizes 3 layers of material over the crack. Two of these layers are fabric. The others use less layers. During the R&D years, we tried less layers of fabric and concluded that 3 layers last more than twice as long as 2 layers.
Time to Install & Prime: The ARMOR Crack Repair System has more layers than either of the other two systems. Thus, it takes a little longer to apply our fabrics than it does theirs. However, because our completed repairs are almost half the thickness of the others, ours take less primer coats of A/R to hide the repairs. Less coats + less time waiting for each coat to dry = less total time to install our product.
The same New Testament spiritual leader, Paul, emphasized this truth when he described human beings as "clay pots"--cracked containers. His point was that the Light (he called it the "glory of God") that lives inside us is able to shine out into the world through our cracks (2 Corinthians 4:7). No cracks, no visible light to the world. God needs our cracks so God's glory can shine through us in order to reveal divine compassion and love to others.
Sometimes, it's the "sinners" that are more appealing than the "saints." Who wants to be around someone who tries to be perfect all the time, who refuses to admit imperfection in themselves or others, and who thinks they're more "righteous" than everyone else? No grace or compassion there. Perfectionism is, after all, an attempt to play God.
Mary Helen Sprecher is the managing editor of Sports Destinations Management Magazine, a niche business-to-business publication for planners of sports travel events, in addition to being an RSI Contributing Editor. She is the technical writer for the American Sports Builders Association and works as a newspaper reporter in Baltimore City.
The suit argues that restrictions on veterinarians violate constitutional equal protection guarantees, because doctors who treat humans have more latitude to treat patients remotely than those who treat animals. It also contends that pet owners and veterinarians have a 1st Amendment free speech right to practice telemedicine.
Take a look at your driveway. Do you see cracks? Water damage? Is it faded, and taking away from your curb appeal? Driveway Armor has worked hard to improve and refine the techniques we use to seal and repair driveways, and repair, resurface and seal asphalt. While not every type of crack is repairable, we have developed techniques to repair the most common forms of asphalt damage. Periodic sealcoating will add curb appeal to your home, and extend the life of your driveway. If you are a commercial customer, we bring our high quality materials and service to jobs of all sizes.
Obviously, the homogeneous armor formula using 1890 Ni-Steel is not applicable here, even if Q(Armor) was raised considerably by the year 1897. The AP shattered and about half made through the plate, so we have an impact just a little below the NBL for that set of conditions. The C.D. Formulae give results that are extremely good for AP, but not for APC, which is to be expected here. My FACEHARD 6.8 formula straddles the shattered AP impact when non-shatter damage is applied in full or is not applied at all. In this case, the shell was not damaged as much by the impact as with most shattered shells, so it was in-between the two extremes, but closer to the full-damage-applied case, as I would think would be more common here. FACEHARD 6.8's APC calculation is not applicable here and is way off, as would be expected.
The homogeneous armor formula using 1890 Ni-Steel is only applicable here if the plate is slightly thicker than 4.25" where hit. The AP shattered and none of the shells did mote than scratch the plate's surface. The C.D. Formulae give results that are way too high no matter where the shell hit that plate. My FACEHARD 6.8 formula is also way too high for shattered projectiles but it straddles the unshattered, but badly broken up, APC impact between its HBL and NBL if the hit was at or near the lower edge where the plate was only 3.5" thick. If so, then this means that either the projectile was not quite as damaged as it usually is and its NBL and HBL went down or, conversely, it was broken into even smaller pieces than usual and more of them were able to get through the hole at the lower velocity, which is essentially the same thing here. This is why the NBL is of little consequence in this kind of impact, where the projectile is in pieces, since only the HBL really matters as to the amount of damage behind the plate. In this case, FACEHARD 6.8 predicts that a bunch of pieces will get through, since the impact is above its HBL, and this is indeed the case (how many to define the NBL is of minimal interest). Since we do not know where the APC shell hit, this is ambiguous, but FACEHARD does give results that are possible. Note also that this was an experimental plate and might not be of the same quality as standard plates to be used on a ship (which have to pass all of the standard tests). Finally, if the hit was near the lower edge, the plate is not as strong, since it can fold back away from the free edge. Most tests are restricted to be at least 3 calibers away from any hole or edge, but this may not have been the case here. Best we can do here.
The homogeneous armor formula using 1890 Ni-Steel is way too low. The C.D. formula for AP is perfect, while the result for APC is way too low. The FACEHARD 6.8 prediction is very slightly low, but well within the possible error in the NBL result. I assume that this was also one of the test results Ensign Davis used to calibrate his formula for AP impacts. Note that the Midvale projectiles deformed and cracked, but did not break up or shatter, though this did not make them act as penetrators any better than the more brittle shells.
The scaling effect is caused by several factors:The fact that the crystals in the steel do not change their size, so the proportion of surface area sticking them together versus the forces within the crystals (usually much stronger) change. The smaller the plate, the bigger the crystals are in proportion and the less surface between them (down to the point of a microscopic plate made up of one crystal!). This crystal-caused effect is rather small for the large plates used in real vehicles and ships, but is evident in all armors, homogeneous and ductile (can bend and tear) or hard and brittle (break suddenly). For this reason, the armor has to be made progressively softer (and, thus weaker, since hardness and strength track rather closely as long as the plate is not breaking in a brittle manner) as the scale increases to keep it from getting too brittle under projectile impact (cracks through too easily), which gradually causes the heavier armor to lose some resistance.
The fact that the brittle materials crack along surfaces (once a crack starts in such a material it tends to self-propagate unless somehow the tip of the crack is locked up). This lockup can be due to reducing stress points (curves instead of corners at edges, using nickel in the steel to replace iron at many points in the crystals, so that the sudden change in metal acts like a piece of cloth in a zipper and jams the crack tip, and so forth) or changing the metal properties so that the material that the crack tip enters is ductile and soft (relatively) and spreads the force on the crack tip, stopping it (an extreme example is that Jello does not crack!). Since a face-hardened plate has the face very hard and rigid, it does not resist cracking too well and the force from a sudden impact can cause the hard face to crack unless there is somewhere for the energy to go. The back layer, if properly made, will allow the shock-wave from the impact to move into it with no sudden changes that can start cracks, only failing if the energy is great enough to begin tearing out the back surface as it reflects back into the plate there (there is no place for most of the shock-wave to go at that point but back into the plate moving toward the face again). This takes a lot more shock energy than the hard face would require to split it open. This problem is compounded by the fact that the energy goes up in step with the weight of the projectile - that is, with the cube of the increasing dimensions for exactly scaled tests - but the surfaces that are cracking can only increase in size with the increase in surface area of the impact site - that is, with the square of the increasing dimensions - so the larger tests simply pour more energy into the cracks at the same rate (same speed of impact), causing the cracks to go farther before they can be slowed or stopped. The thicker the hard, brittle face layer in a face-hardened plate in proportion to it total thickness (the deeper the "chill"), the more this cracking can grow before the ductile back layer can disperse the remaining energy. This means that the thicker the face, the worse the plate resistance becomes for scaled tests with large projectiles hitting scaled-up plates. Conversely, with smaller scales, this works in reverse and can make thick-faced plates stronger against small projectiles which have much less weight and, thus, energy at a given striking velocity.
The method of plate failure is crucially important. For hard materials struck in their face with enough energy to punch through, the entire face will be punched out a roughly cylindrical plug like a cork from a wine bottle, tearing out the back layer in a cone shape (usually) in a thick-faced face-hardened plate as the face acts like a billiard cue ball hit by the player, with the backing layer acting like the numbered billiard ball. However, in this case, the cue ball and the numbered ball fuse together and exit the plate back at a reduced velocity (due to the increased weight of this one large mass), though it may break apart as it exits the plate back, of course. The continued force of the projectile on the face ensures that nothing (except some surface flakes, perhaps) can move in that direction, focusing this cork effect into a narrow cone or cylinder directly in front of the projectile nose, at least a low obliquity (near right angles). While this cork effect puts a very large stress on the projectile nose tip, which must essentially stop cold as its energy is transferred to the face layer and, eventually, the entire plug of face plus back layer - increasing the chance of the projectile nose shattering into pieces or suffering some other drastic damage, which usually reduces the ability of the projectile to continue trying to penetrate - this cork is also a surface failure and follows the square-cube law mentioned above, so it actually takes less energy to make happen than if the projectile had to tear open the entire thickness of the plate made of a soft, ductile material before it could go through. Thus, the formation of a plug indicates that the plate is good at breaking up a projectile's nose (shatter into small pieces before the shell can penetrate more than a tiny distance being the most effective form of damage), but it also indicates that the plate is rather brittle and takes less energy than a similar softer plate that does no form such plugs (assuming the same strength for this solid all-the-way-through-softer armor ("homogeneous") to the back layer of the hardfaced plate). For small-scale tests, the energy that the projectile has due to its weight is going down faster than the needed energy to plug the plate, so if the scale is small enough, plugging does not hurt resistance and can even help it, again assuming similar soft-portion strength to all of the armors involved in the comparison. Note that if the face layer is very thin, as in Harvey armor in the thicker plates, the punching out of the face does not go very deep before the tough, ductile steel in the rest of the plate stops it, after which the projectile must push through more-or-less like a ductile, homogeneous plate, but if the nose tip of the shell is shattered, this becomes much more difficult, causing the projectile to crush itself between its base moving forward at full speed (at least initially) and the broken nose trying to move forward at slow speed (relatively) through the steel armor. A shattered, weakened, flattened nose doesn't penetrate thick armor very well at right angles!
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