Special Xeon in Mac Pro, MBP battery woes, iPod takes a bullet

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  • Reply 101 of 113
    There are some cool dudes around here.



    The US military has often made purchases for mil-spec that did not meet the spec. They have also often payed for household-spec at mil-spec rpices.



    In short: our military is not a model purchasing ententy and therefore should not be used as an example.



    Remember the original torpeddoes our boys got in WWII? Missed almost every time.
  • Reply 102 of 113
    Quote:
    Originally Posted by Bergermeister View Post


    There are some cool dudes around here.



    The US military has often made purchases for mil-spec that did not meet the spec. They have also often payed for household-spec at mil-spec rpices.



    In short: our military is not a model purchasing ententy and therefore should not be used as an example.



    Remember the original torpeddoes our boys got in WWII? Missed almost every time.



    If I'm not mistaken, the DOD actively participates in prototype development, and is directly involved is various destructive and non-destructive tests. Once the development cycle is over, final specifications are generated and bids are taken (or if SSJ sent to the primary contractor for a RFQ). From what MIL SPEC's I've seen the manufacturer must submit test results based on some test criteria specified in the MIL SPEC. The DOD is rather famous for procurement screw-ups.
  • Reply 103 of 113
    vineavinea Posts: 5,585member
    Quote:
    Originally Posted by franksargent View Post


    Vinea,



    I'm talking about the entire IBA vest with the underlying human body elastic properties (flesh and possibly a broken rib cage (i. e. the trauma wound)) preventing a human fatality. Conditions circa 2007 IBA vests, NOT circa 2004 IBA vests! This is 2007 isn't it?



    Yes.



    Quote:

    You seem to be talking about the ESAPI plate in and of itself, while I'm talking about the entire IBA vest on a soldier with a shot into the chest area (as actually happened).



    Nope. Whole system.



    Quote:

    And given that AK-47 rounds travel ~400 fps less then the V50 of 2,750 fps, and that the energy is ~mv^2/2, results in a safety factor of ~1.4.



    You were getting loose with your claims. We're in this little sub-thread because you were pushing numbers at folks while claiming to be a subject matter expert...



    Like these numbers. Muzzle velocity only tells part of the story. True, the 7.62mmx36 is slow enough to the point that no one bothered to (continue to) make a real AP round for it. Bullet design and material are also a factor in pentration capability. The API-BZ penetrates more material despite the same 2400 FPS velocity of the 7.62 x 39 ball.



    The most questionable number you've stated is that an ipod wouldn't slow a bullet by even 0.2 fps and could never impact the outcome. Mkay...I can think of at least one based even on the pictures we see...



    Quote:

    Why yes, I'll take your bet under the real world conditions mentioned here, an IBA vest with an orthogonal single shot (with an AK-47 round identical to the actual Iraq situation) into the IBS chest area (with it's underlying ESAPI plate, underlying Kevlar multi-ply ballistic fabric, and underlying human elastic properties) not resulting in a fatal wound!



    It still a silly bet on your part, especially volunteering to be the dummy. The odds of your winning are quite high given the IBA can stop multiple hits from the M2AP but you're risking a lot on the QC of the manufacturer of the plate and vest. More than $20 worth.



    But now you're getting specific which is interesting. I went back to your old posts and notice they've been edited but I had thought you had been vague on 7.62mm in general...yes, the context was an AK-47 but if you're going to play expert don't be surprised that folks hold you to a higher standard.



    It would be interesting to know where in the left chest he was hit and the position of the iPod in relation to the plate.



    But hey, for $20 I'll watch someone shoot at a vest. You supply the vest. I'll supply the bullets.



    Vinea
  • Reply 104 of 113
    vineavinea Posts: 5,585member
    Quote:
    Originally Posted by Bergermeister View Post


    Remember the original torpeddoes our boys got in WWII? Missed almost every time.



    I think PEO Soldier avoided this fate even with the controversy of dragon skin. The interceptor is better than anything else we've ever fielded not counting variants tested within the SOCOM community.



    But I do think PEO Soldier does suffer from some of the same hubris we see in other DoD programs. Some of the shortcomings of the originial vests should have been caught earlier. Bad weight distribution is just bad design of the outer vest...not limitations of the underlying materials.



    Vinea
  • Reply 105 of 113
    Quote:
    Originally Posted by vinea View Post


    Yes.







    Nope. Whole system.







    You were getting loose with your claims. We're in this little sub-thread because you were pushing numbers at folks while claiming to be a subject matter expert...



    Like these numbers. Muzzle velocity only tells part of the story. True, the 7.62mmx36 is slow enough to the point that no one bothered to (continue to) make a real AP round for it. Bullet design and material are also a factor in pentration capability. The API-BZ penetrates more material despite the same 2400 FPS velocity of the 7.62 x 39 ball.



    The most questionable number you've stated is that an ipod wouldn't slow a bullet by even 0.2 fps and could never impact the outcome. Mkay...I can think of at least one based even on the pictures we see...







    It still a silly bet on your part, especially volunteering to be the dummy. The odds of your winning are quite high given the IBA can stop multiple hits from the M2AP but you're risking a lot on the QC of the manufacturer of the plate and vest. More than $20 worth.



    But now you're getting specific which is interesting. I went back to your old posts and notice they've been edited but I had thought you had been vague on 7.62mm in general...yes, the context was an AK-47 but if you're going to play expert don't be surprised that folks hold you to a higher standard.



    It would be interesting to know where in the left chest he was hit and the position of the iPod in relation to the plate.



    But hey, for $20 I'll watch someone shoot at a vest. You supply the vest. I'll supply the bullets.



    Vinea



    Vinea,



    Almost all my posts get edited, not to change the text but to change grammatical errors, structure and spelling (although I've just turned on the OS X spell checker two days ago, so that helps some, but my word structure is still atrocious, IMHO)! I'm kind of a terse person, my speech is minimalist at best, when I talk to people about something, I see puzzled expressions, and then I have (to me) get long winded for them to understand, I guess it's my Vermont upbringing.



    Heck, I've even been accused of changing my posts in mid-flight as it were, I mean, I see a grammatical error or shortly after posting (minutes) I see something that wasn't clear or missing, edit the post (I'm a very slow writer BTW), and by the time I hit the submit button, someone else has responded to my original post, and I get accused of changing it AFTER the other person responded to my original post.



    Sounds confusing I guess, but whatever.



    And please, go back to my first post, I clearly stated that I was not a ballistics expert, let me repeat that:





    I am not a ballistics expert.





    Heck I've fired a gun twice in my lifetime (22 and 12 gauge shotgun), both times I was in junior college ~ 35 years ago! BTW, you sound like you know a lot about bullets and/or guns?



    But as I also stated I do have expertise in structural mechanics/analysis (aced all of 'em in college) material science (aced that one too), and have significant design and analysis experience since my schooling. And that is why I questioned the initial report, then as I looked into the matter it became clearer (to me at least) that the iPod would not (IMHO) have played a significant role in this incident.



    As to me being Buster during the live fire test, well you see I guess I'm kind of a risk taker, you know "Dare to be stupid!"



    And I would want to simulate the actual incident as close as possible, sans iPod.



    That is all.
  • Reply 106 of 113
    melgrossmelgross Posts: 33,254member
    Quote:
    Originally Posted by franksargent View Post


    Heck, I've even been accused of changing my posts in mid-flight as it were, I mean, I see a grammatical error or shortly after posting (minutes) I see something that wasn't clear or missing, edit the post (I'm a very slow writer BTW), and by the time I hit the submit button, someone else has responded to my original post, and I get accused of changing it AFTER the other person responded to my original post.



    Sadly enough, that happens to me as well.



    for some reason, I don't always spot all of the mistakes while in posting mode, but only after the post comes back up. The spell check doesn't always work either, because a number of the words we use here aren't in the checker at all, or because it doesn't understand context.



    Sometimes, I read what I've just posted, and realize that something isn't as clearly stated as it should be, and so I'll change it, or that I forgot to add a sentence (or more) that makes the argument clear. Or a link. Or that I somehow posted the wrong link, or one that no longer works, or needs a password. Sigh!
  • Reply 107 of 113
    vineavinea Posts: 5,585member
    Quote:
    Originally Posted by franksargent View Post


    Vinea,



    Almost all my posts get edited, not to change the text but to change grammatical errors, structure and spelling (although I've just turned on the OS X spell checker two days ago, so that helps some, but my word structure is still atrocious, IMHO)! I'm kind of a terse person, my speech is minimalist at best, when I talk to people about something, I see puzzled expressions, and then I have (to me) get long winded for them to understand, I guess it's my Vermont upbringing.



    I thought I recalled that one sentence simply said 7.62 and not specifically for the AK-47 making it a blanket statement. I probably mis-remembered and I shouldn't have brought it up.



    It was really the 0.2 fps comment that caught my eye.



    Quote:

    And please, go back to my first post, I clearly stated that I was not a ballistics expert, let me repeat that:



    I am not a ballistics expert.



    Yes you said that but you claim specific knowledge of domain...hence "subject matter expert".



    Quote:

    ...where I work (US Army)...



    Am I a structural engineer? Yes!



    Do I work for the US Army? Yes!



    Have I been doing active research into these ballistics materials over the past 3 years? Yes! We have a ... structure with underlying ... structures that may need to be protected from small arms fire! It's called need to know. We have also used these materials (...) several times (...) as ... in the aforementioned ... structures.



    Could I contact some people I know at U.S. Army Soldier Systems Center (Natick)? Yes!



    So, you work for the Army, do active research into ballistics materials and know folks at Natick. Sounds like a SME...



    Vinea
  • Reply 108 of 113
    franksargentfranksargent Posts: 4,694member
    Quote:
    Originally Posted by vinea View Post


    I thought I recalled that one sentence simply said 7.62 and not specifically for the AK-47 making it a blanket statement. I probably mis-remembered and I shouldn't have brought it up.



    It was really the 0.2 fps comment that caught my eye.







    Yes you said that but you claim specific knowledge of domain...hence "subject matter expert".







    So, you work for the Army, do active research into ballistics materials and know folks at Natick. Sounds like a SME...



    Vinea





    OK,



    So perhaps the 0.2 fps was an overstatement, so I'll admit that one.



    My expertise is in the mechanical properties of the high modulus synthetic fibers (like webbing, slings, ropes (linear, twisted, and braided constructions)) using similar materials as those used in ballistics fabrics, but not the ESAPI/SAPI ceramic plates.



    We have used Kevlar 29 and 100 as well as Twaron 2200 constructions as linear tendons on 4 different occasions (1 a prototype, 3 were Froude scale models).



    Were are in a 6.3 ACTD development program of a Lightweight Modular Causeway Syntem for the US Army. The LMCS uses floatation tubes, a lightweight metal (or perhaps at some future date an FRP) superstructure, and linear high strength tendons.



    It's basically a floating bridge, with the floatation + tendons/superstructure providing enough stiffness to carry an M1A2 Abrams from ship to shore. The LMCS is also a compliant structure able to survive in SS6 conditions.



    Anyway, at one time (a year or so ago), I looked into ballistic fabrics as a possible means of providing small arms protection of the floatation tubes.



    That is all.
  • Reply 109 of 113
    vineavinea Posts: 5,585member
    You have pm.
  • Reply 110 of 113
    iposteriposter Posts: 1,560member
    Quote:
    Originally Posted by franksargent View Post


    OK,



    It's basically a floating bridge, with the floatation + tendons/superstructure providing enough stiffness to carry an M1A2 Abrams from ship to shore. The LMCS is also a compliant structure able to survive in SS6 conditions.



    Sea State 6? And carry an Abrams? That's one strong floatie you have there!



    SS6 was unpleasant when experienced shipboard, can't imagine there would actually be unloading going on during it!!



    (I know, the bridge would survive the storm but not actually be used during it!)
  • Reply 111 of 113
    melgrossmelgross Posts: 33,254member
    Well, my experience with Kevlar was when I called DuPont and ordered several yards to put on the bottom of my modular couch to keep my ferrets out. Didn't want the little buggers getting squashed in the springs.



    They were interested in the usage, and wanted me to call back and let them know how well it worked. It worked well.



    Tough to shoot the pneumatic air staples through the fabric into the oak through. They were chisel headed, and kept bouncing off.



    I finally had to use pointed ones instead, so that the tips would slide between the fibers.
  • Reply 112 of 113
    vineavinea Posts: 5,585member
    Quote:
    Originally Posted by iPoster View Post


    Sea State 6? And carry an Abrams? That's one strong floatie you have there!



    SS6 was unpleasant when experienced shipboard, can't imagine there would actually be unloading going on during it!!



    (I know, the bridge would survive the storm but not actually be used during it!)



    Evidently the thing even holds the equivalent weight of an M1 with several floatation units punctured. Presumably not in SS6...I would think you wouldn't want any vessels close to shore in SS6...



    Vinea
  • Reply 113 of 113
    franksargentfranksargent Posts: 4,694member
    Quote:
    Originally Posted by vinea View Post


    Evidently the thing even holds the equivalent weight of an M1 with several floatation units punctured. Presumably not in SS6...I would think you wouldn't want any vessels close to shore in SS6...



    Vinea



    Yes, you guys are correct. The SS6 condition is for an intact unloaded causeway. In numerical simulations (that other structural engineers on the LMCS team have conducted BTW) we have had up to 4 adjacent floats removed, and can maintain positive freeboard for the M1A2 as it passes over the removed floats. However, we would not want to conduct what have traditionally been called LOTS (or JLOTS) under a 4-float-missing situation for very long, if at all, we would want to replace floats in situ as it were ASAP (for example, if we were offloading a bunch of M1A2's, for lower military weight classifications, the urgency would not be as great).



    As to typical offload SS, even SS2 has been shown to reduce throughput, and by SS3 most throughput operations pretty much come to a standstill (all of what I have said is in the public domain) for classic LOTS/JLOTS operations. As you may well be able to guess, the choke points are at the transfer points of equipment/vehicles from ship/lighterage/causeway.



    As to SS6 conditions these tests were simulated in nearshore water depths of 20 ft and 30 ft, so that while real waves are directional and irregular in nature, they are "roughly" sinusoidal only under deep water conditions, but in shallow water the the waves become asymmetric (i. e. flatter troughs and more peaked crests) and eventually break (as you are all well aware), in a hydraulic sense the wave front goes supercritical (unstable, Froude No. > 1). The wave heights become depth limited.



    So anyway the large traffic load (over ~2 modules) of an M1A2 on the causeway ends up loading the structure locally more so than shallow water waves, that change in shape and/or break due to nearshore beach type bathymetry. Also, we could claim higher SS survivability then we have, but we ran out of wavemaker stroke capability during the physical model tests at OSU's tsunami basin.



    So basically, the causeway moves in waves VERTICALLY, like a snake moves in water HORIZONTALLY. Thus, the curvature (moment) the structure takes in waves is significantly less than the local curvature (moment) the M1A2 ~concentrated load (over ~20 ft) imposes for the modeled rotational stiffness at the LMCS module joints.
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