Structural Metal Career Guide and Counseling

Question: is it impossible to run out of structural metals such as iron, due to space dust? One of the space documentaries I watched recently said 100 tons of space dust (mainly consisting of water and metals, like nickel and iron) reaches earth every day. In theory could this space dust be collected, and made into structural components of buildings, ect? I know it isn't economical and is completely impractical; I am just wondering if it is possible in theory...

Answer: In theory yes, in practically, no. The surface area of the Earth is some 510,967,783 km. That means that it would take almost 14,000 years for the entire surface of the planet to be covered by one ton of space debris. That can't occur because wind and rain would either wash the dust a way or keep it aloft in the atmosphere. You would need to build a collector big enough filter the entire atmosphere of the planet. Not only is that an incredible technical challenge, I am sure it would FAR out weigh the amount of space dust you collected.

Question: The casting of molten metal is important in many industrial processes. Centrifugal casting is used for? manufacturing pipes, etc. a cylindrical enclosure is rotated rapidly and steadily about a horizontal axis. Suppose that a copper sleeve of inner radius 2.10cm and outer radius 2.20cm is to be cast. To eliminate bubbles and give high structural integrity, the centripetal acceleration of each bit of metal should be 100g. What rate of rotation is required? State the answer in revolutions per minute.

Answer: a = v^2 / r So a = 100g = 980m/s^2 Which radius to choose, 2.1 or 2.2? Choose 2.1 to make sure the entire distance from 2.1 to 2.2 experiences at least 980m/s^2 of acceleration. (The outer radius experiences a higher velocity than the inner radius.) So once you have v, solve for revs per time by noting that the revs per time times the circumference (distance per one revolution) equals v: revolutions per second * 2Ï€r = v I'll leave it to you to convert from rev/s to rev/min.

Question: What types of metal wire can be soldered and what types of flux and solder do you need for each of them? I am a metal artist and I am getting ready to teach a class to older children. My dilema is this: I weld most of my items and rarely have I soldered. It is inpractical for me to use or do welding while teaching this class; hence, I have decided to do wire sculpture with the students. We will of course explore this by primarily twisting, bending, and hammering the wire for desired effects and shapes, but, I would like to be able to connect certain structural areas in a more permanent way than twisting. I am familiar with soldering copper and brass wire, but the cost of these metals are currently very high; hence, I am attempting to explore other more affordable options. The hardware stores carry a variety of galvanized wire in several guages. I know that the zinc (galvy coating) is unsafe in terms welding, but is there a way to solder this wire, and is it safe?

Answer: Galvanized metal solders very easily, IF you flux with dilute muratic acid. Of course, you might not want to use this with kids. You could experiment with distilled vinegar and see if that's strong enough to flux with. Soldering temps are too low to vaporize zinc, so at least that won't be a problem. I've used galv. wire (usually sold as electric fence wire) for these kind of projects before, and haven't been happy with it. It's very stiff, and hard to manipulate--and I was teaching college students. The wire I prefer is re-bar tie wire--about 18 g. It's black, soft iron--a 5# roll costs about $4. I'm teaching a sculpture class in the fall and am having exactly the same questions as you--my plan is to have students braze the wire with propane or MAPP gas torches, but I'd prefer soldering. I still need to test the re-bar wire and see if there's any way to solder it--if I come up with anything, I'll add on to this answer, or add to comments if you've already picked a Best Answer.

Question: What is the "strongest" metal alloy/material? I'm looking for a metal alloy/material that would be used in subzero temperatures (ie: space). Something that could be melted into sheets, such as for armor or structural plating. It need to be able to withstand both high impact velocities and high heat. Also, if you can give psi measurements with an example, my tiny brain would be able to keep up. It does not have to be made in a factory, or laboratory. Even if it is theoretical, but poissible 50 years from now; please, feel free to put it up.

Answer: carbon 40 is the strongest known material in the universe but it is made in a factory and it is very expensive. it is stronger than the diamond which is the strongest natural material. it is very strong

Question: How can this PVC/metal kitchen door be reconditioned to useful life? Hi... Have a problem with our back door.. the kitchen one leading to the backgarden. Photos here: http://www.stormkrewsaders.com/recond/door_recon1.html Any useful tips or thoughts on how I could recondition it? I'm bad with DIY but can usually do something so long as I get stuff planned out clearly in advance. It's PVC metal... and quite old. Except.. it's still in good structural condition.. but the paint has worn in areas.. and the handle and lock (mortice 5 lever suitable for insurance) is a real pain cause its worn. I'm being pestered to pay out like £500 for a new door by family... and.. well... I don't want to cause that's alot of money. If I can get the door working fine again.. then they will be much happier and get them off my case. Thanks. :)

Answer: The good news is that your door can be saved! Your best bet is to lightly sand the door except where there is metal showing. You will need to use a metal priming paint before you can paint it. The primer will help the paint to stick to the door. Don't forget to mask off or cover up the glass before you paint. As for the latch plate, you can try longer screws. You can also try filling in the holes with a metal putty that when it hardens it is as strang as steel. Then redrill your holes. Hope this helps the door look GREAT!

Question: What are the possible loads of a truss based on NATIONAL STRUCTURAL CODE OF THE PHILIPPINES 2001? i need the load for corrrugated sheets/asbestos roof/metal sheet roofceiling weight for plywood and timber/hardiflex and metal frames;windward-side wind pressure and leeward-side wind pressure in General SantosCity;and wind pressure formula.These are all based on the 2001 Natonal Structural code of the Philippines.

Answer: i don't have an idea about these codes but i think when you want to design a truss goto the code you will find the combination of loads you will take in consedration the rain and snow loads in addition to the dead (Own weight) and live loads (from the erection manship) then you will take the highest value of the combinations and use it, but keep in mind if the truss is not simply supported (means if you have an internal support) you will need a design program such as: Staad.pro or SAP2000 i hope that you got the main concept.

Question: Alkali metals cannot be used as structural metals because they are__elements.? Filling the blank

Answer: Reactive? If any water touches pure alkali metal, then, BOOM!! The metal reacts exposively.

Question: Pros and cons of using metals as structural materials?

Answer: loads of properties - strong, malleable to some extent so it wont snap bad point is that it expands and shrinks in heat and cold respectively, so it might fracture depending on what type of metal it is so you have to give it space to expand and contract

Question: How can I contract structural engineering services for a sculpture online and inexpensively? I need to have the strength of a bent piece of sheet metal analyzed to see the maximum load it can support given some gauge of stainless steel. I would also like some process engineering services to determine the best way to assemble the final sculpture. I would like to know the best and most economical way to contract these services online.

Answer: Go here to search the various structural engineering firms:- https://online.acec.org/acecforum/acecLogin.asp They ain't cheap! Some sculptors have hired firms like these, but you need a wealthy sponsor such as the City of New York or whomever. Or you could get yourself a copy of Solid Works and do your own analysis. Or you could build a test piece and measure the failure load yourself. Sculptors and civil engineers are not generally a happy mix. You will have your work cut out for you, as all sculptors do. The ways to stay on the right side of an engineer are as follows:- 1) All financial arrangements must be agreed in advance. Do not show up with no money and ask what to do next! 2) Always follow through immediately on things like returning phone calls, providing information and so forth. 3) Do not change anything once you have asked for an analysis to be performed. If necessary, do another analysis (at extra cost, of course) later. Good luck - you are going to need it!

Question: What is the thickness of the metal used for construction of intermodal containers? I'm looking for both the sidewall material and the structural columns. What grades are typically used? I know there is some degree of variance, and that more recently the quality has been declining; I just want to know what is most typical. I've checked the usual sources, starting with the obvious Wikipedia, but everything only lists overall dimensions, and not raw material grades. Thanks!

Answer: Anywhere from 5/32 to 1/4" is pretty standard from what I know.

Question: why transition metals are useful as structural materials, and as electrical and thermal conductors? actually, i also dont know anything about what im asking now..i just copy it from my workbooks.. sorry if the question not clear..

Answer: the layers are regular, the molecules are close together to allow electrical currents to pass through

Question: Why are large telescope reflectors made of glass instead of a sensible structural material like steel? Primary reflectors for astronomical telescopes up to 8.4 metres diameter are made of glass. As an ex truck driver I can't imagine a more stressful job than driving an oversize, expensive brittle object like that to the top of a mountain to be installed in an observatory. Why not make it out of steel? Make the surface parabolic by spinning it until it's solidified, instead of grinding it. Then plate or vapour-deposition a layer of inert silvery metal like platinum on the surface.

Answer: A metal surface can be polished to about 1/4 wave (about 125 nm) accuracy. This was good enough for Isaac Newton, but glass can be polished to tolerances better than 1/100 wave (5 nm). More importantly, especially for large mirrors, metal expands and contracts much more with changes in temperature than glass does, and even glass mirrors can be useless until their temperature has stabilized. Spin-casting is actually used for some large telescope mirrors, and it is theoretically possible to make a telescope using a spinning dish of liquid mercury as a mirror. A mercury telescope could only point vertically, but it's an interesting concept.

Question: could a metallomic approach be useful in elucidating metal ion location within Ribonuclease H11? Structural data for this enzyme has been determined to date from X ray crystallographic studies. Because of this approach, an assumption has been made that the crystal enzyme structure has the same structure as the enzyme in solution, as it would be in the cell. This is very open to debate amongst researchers in this field.Could metallomic techniques be applied to the study of this protein in it's substrate bound form in solution?

Answer: Do you really expect a coherent and accurate answer to that question on here? You'll be lucky if you get one. If the laws of probability are anything to go by then I have a 50/50 chance of offering the right answer, so I shall say yes!

Question: metal frame pool water level? in metal frame above ground pools is there a reason that the water level in a 48 in deep pool is only 42 in in a 15 ft pool and 38 in in an 18 ft pool. is this a structural issue.

Answer: Your water level should be approx. mid-point of your skimmer no matter what the depth of your pool is. Since there is little or no coping around above ground pools to keep the water in during swimming or playing in the pool, it is a good idea to have 6 inches of room for the waves to be contained as much as possible. Just make sure you have a high enough water level to avoid air being sucked into the system due to the vortex created in the skimmer during pump operation and it should be fine.

Question: How do I determine if cracks in a new concrete pad are structural? What is contractor's responsibility? No other cracks on property. Cracks in the area graded & built up, not tampted of a 40'x40'x4" concrete slab floor of a metal building. Hairline cracks started in 3 months & are expanding. Have contacted the builder but they avoid me. The NE corner seems to be settling & cracking. If you place a long level on a crack you can see the concrete is dropping. How serious is this? The sub-contractor that did the clearing & grading missed the location by 2'. The concrete sub-contractors had to move the forms by hand digging them. The footings are 2' bigger. That is alot of concrete to shift. I have lost confidence in the grading contractor. I believe that the northeast corner was not graded correctly and that corner is settling & cracking. How far will it drop? How do I determine the extent of the damage? How do I have the problem corrected? Does it need to be redone or is it just cosmetic & a floor sealer would repair it? How do I negotiate with the contractor? Are there control joints in the concrete? Yes. The joints run down the middle north to south and east to west cutting it iinto quarters. And it was ok'ed by the city inspector on 12/28/05 Building Approvals 200 Set backs 204 Footings, forms and steel 208 Slab grade However there is a section on the permit form concerning Grading and site work that was not checked. Grading/sitework 100 Rough grading/building pad 104 Storm drain structures 108 Precise grade 199 FINAL GRADING I assume that it was not needed as alot of lines were not written off.

Answer: If I were you, I'd start gathering evidence now so in the case that this becomes a major problem, you have some proof. Save all communications to the contractor. This may be their fault, and if it is, it may be their responsibility to fix it. take pictures. Copy all written documents. Tape record all phone conversations if possible. Save all emails. You may need to prove that you contacted them, and that you noticed the problem long ago if this ever becomes a problem. Whether it is serious or not depends on where it is and what kind of building it is. On a sidewalk, probably not. In a parking garage, yes. Still, if their policy or warranty covers it, they will have to fix it regardless of how serious the issue is. Hope I helped.

Question: Porcelain fused metal crowns height adjustment: when can it compromise the crown? I just had two PFM crowns inserted (last two teeth at the bottom). After soreness and pain were gone I noticed none of the crowns have the same height my natural teeth have. They are pretty filed down..the back crown feels & looks almost completely flat. Basically the crowns have no (or very little) cusps and grooves compared to my other teeth. Also, the "stain" the crowns have in the grooves doesn't look natural. Overall, I feel this is a substandard work. Now, the first question is: if the dentist had to file down the crowns too much, at which point does the crown become compromised? can the porcelain be damaged by filling it down? any structural damage done to the crown? Second, now what? I can complain to dentist, but in the end, what could be done? Can my insurance help me in fixing this? my benefits only allow for a replacement in five years...

Answer: The dentist can use porcelain polishing burs to adjust the height of your PFMs. The occlusal, or biting surface, of the crowns consists of a thicker layer of porcelain, so there is little chance of damaging the integrity of the crown; however, if the layer becomes too thin, there is a possibilty of fracturing/chipping the crown. This can happen regardless, and not just on the biting surface. Don't wait too long to have your dentist make the adjustments. You can have some discomfort if they are not corrected; or even chip the porcelain by exerting pressure on the PFMs if they hit first when you close/chew/bite. If the office does not have an in-house lab but one that is in your town, you can ask that the lab tech come in to see what the problem is. (Our lab tech is literally down the street from our office; he sometimes comes in prior to treatment to take photos and notes to avoid situations similar to yours.) Your insurance company should not be involved in this portion of your treatment, as this is just considered an adjustment issue. The work has been completed, the pre-authorization has been taken care of. The ins. co will be involved if this escalates to a re-treat issue.