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    #21
    PLAGIARIZM. WAS IT ACCIDENTAL ?
    https://pdfpiw.uspto.gov/.piw?docid=...6RS=PN/3241834

    Welcome to ESN secret bakery.. The admittedly innovative formula of tensor rubber, it all comes from American patent 1965.
    Last edited by igorponger; 10-15-2021 at 03:25 PM.

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    #22
    Quote Originally Posted by zeio
    Seeing pnachtwey educate the forum by throwing around terms such as closed- and open-cell rubber, air pockets and "heavier oils...will ruin your rubber by filling the air pockets with nearly uncompressible oil" gives me the chill. It is so uncanny.

    Thank table tennis god he's finally reached that friggin' point. Would've saved yours truly so many keystrokes if he were that smart 6 years ago. Fuk yeh! It took just 6 friggin' years for our omniscient engineer to acquire, better yet, verify this much knowledge!
    I don't see what zeio is complaining about. And Zeio was the noob and still is a noob.
    Zeio still need to explain reduced mass.

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    #23
    *Sigh* Omniscient engineer is clearly out of his depth here. Let me put you in your place on the other topic.

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    #24
    Quote Originally Posted by zeio
    *Sigh* Omniscient engineer is clearly out of his depth here. Let me put you in your place on the other topic.

    Vague claims you cannot justify are easy to make.
    You still haven't explained reduced mass.
    You just copied a bogus paper that no one understands that it doesn't apply to TT. That is how I know the whole MYTT forum is full of noobs. Even those that claimed to be engineers or have PhDs in physics.
    The fact you have even tried to explain reduced mass shows you really didn't know what you were posting.

    You called me a noob in the link you posted for commenting about tension. Show us an equation where tension is used to compute speed or spin.
    TT manufacturers dupe noobs like you when they mention our rubber has high tension. What holds the rubber in tension? Where is tension used in an equation to computer speed or spin? We are waiting.



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    #25
    Reduced mass? Since you insist, let's do it.

    Remember the "paddle mass and speed" and "power vs weight" threads you started on Mytt and OOAK? For the curious minds, these 2 threads were what ultimately got our omniscient engineer banned. He argued that mass had little to do with COR as his math showed, but didn't understand that the ball does not see the entire racket mass, hence the term reduced mass or effective mass(which has a profound effect on COR), unless the shot hits in the center of gravity, which players don't on most shots such as loop, drive, counter hit, smash, chop, push, serve etc., except for blocking.

    For those who are not familiar with JRSDallas, check out his thread on Blade Performance Vs Wood Type and Design.

    My post:
    https://mytabletennis.net/forum/foru...d-speed#471271
    Of particular interest here is the reduced mass(Mr, the effective mass involved during a collision), which takes into account the mass of racket(MR), the equivalent mass of arm(MH = 1kg), the moment of inertia(IGH), and impact locations(A-H) from the center of mass of the combined racket-arm(Figure 5 and 6).
    JRSDallas's posts:
    https://ooakforum.com/viewtopic.php?p=156206#p156206
    There has been no discussion of the Effecitve COR (ECOR) which takes into account where on the blade the ball strikes, the energy that the collision couples into the blade vibrations, or the efficiency of the vibration constructively or destructively coupling back into the rebound of the ball (i.e. the ECOR is also varies with impact velocity and the blades effective mass at the point of impact).
    https://ooakforum.com/viewtopic.php?...7d4397#p155245
    A simple test shows that the effective weight of the TT bat at some points of impact is essentially nearly equal to the weight of the TT ball, i.e. a ratio much lower than the Baseball bat to baseball weight ratio.
    https://ooakforum.com/viewtopic.php?p=156206#p156206
    Now some blades have been specifically constructed to have higher COR at lower mass (Ishlion) than most other blades, and pnach's used the Ishlion's speed to weight to argue that his math was right.....but.....his actual argument was that people who said there was a correlaton with weight were wrong.
    Unfortunately he did not understand what he did not understand and in both cases he was wrong.
    Last edited by zeio; 10-16-2021 at 06:10 PM.

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    #26
    Quote Originally Posted by zeio
    Reduced mass? Since you insist, let's do it.

    Remember the "paddle mass and speed" and "power vs weight" threads you started on Mytt and OOAK? For the curious minds, these 2 threads were what ultimately got our omniscient engineer banned.
    That is because they called me a noob like you just did and when I present facts all the so called PhDs hide. In my eyes all the HaggiV forums are full of idiots. They really should have looked up who I am.

    He argued that mass had little to do with COR as his math showed, but didn't understand that the ball does not see the entire racket mass, hence the term reduced mass or effective mass(which has a profound effect on COR), unless the shot hits in the center of gravity, which players don't on most shots such as loop, drive, counter hit, smash, chop, push, serve etc., except for blocking.
    Zeio wants to change the definition of COR.

    zeio did a calculation of the speed after impact on mytt. zeio only used the conservation of momentum. This resulted in zeio calculating the ball speed after impact was slower than the paddle speed. I let wturber give zeio grief about that.
    zeio has be wrong on so many things.


    Zeio, why can't you do something simple like insert a link?
    JRSDallas did a lot of research on the vibration of paddles. I have not problem with that. The problem is that he was mostly interested in the 4th mode of vibration instead of the primary mode which is must important when impacting the ball. There other data posted using the primary frequency that is more useful If rubbers are attached to the paddle then all the vibrations will change. Also, any vibrations are lost energy that isn't returned to the ball. All the vibrations you feel in your hand are energy that isn't returned to the ball. Does ANY BODY HERE now how to calculate the energy as a function of frequency and amplitude? I do. This is a major problem I come across when people are doing sinusoidal testing. Think about that.

    Zeio, refute that.

    Zeio still hasn't explained reduced mass. Zeio copies stuff without understanding. This is common in China and apparently in Hong Kong too. It happens in the US too but not as often. He hasn't shown an equation that uses tension even though he called me a noob for saying tension is a fraud.
    I have a pdf waiting to post that calculate the speed of the ball after impact. I do it two ways. One is the way I posted a link to on wikipedea that all the HaggisV forums ignored. The other way is using the reduced mass formula. They both end up with the same answer. So why was I called a noob? I don't forget and I don't forgive.

    BTW, I "evaluate" engineering papers too. Yes I am a critic.
    So everybody, seek facts. Don't repeat myths.

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    #27
    Quote Originally Posted by brokenball
    When I was a noob...
    Thank you for confirming again what I confirmed 6 years ago - https://mytabletennis.net/forum/foru...tension#852660

    A noob calling others noobs asking why others called him a noob. 🤣

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    #28
    Quote Originally Posted by zeio
    Thank you for confirming again what I confirmed 6 years ago - https://mytabletennis.net/forum/foru...tension#852660

    A noob calling others noobs asking why others called him a noob. 🤣

    You still haven't explained reduced mass.
    You have explained what mass is reduced.
    You haven't explained how to use it.
    You just copy other people's work without understand.
    You haven't found an equation where tension in used.
    You haven't explained what holds a "tensioned" rubber in tension.
    You haven't found an equation where hardness is used to compute spin or speed..
    You tried to compute the speed after impact on mytt. You only used the conservation of momentum formula. You calculated the speed of the ball after impact would be slower than the speed of the paddle which didn't make sense. You needed to use the very same formula I posted links to. The same ones that you and others ignored.
    Zeio and HaggisV should have found out who I was before attacking what I posted.
    This is why you and Haggisv are the noobs.


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    #29
    Quote Originally Posted by brokenball
    You still haven't explained reduced mass.
    It was interesting to read those posts. Why do you say he didn't explain reduced mass. It was said in there, that it is just the effective mass of the arm/paddle which collides with the ball. They just use the word "reduced", they could have used other word, say "estimated". ((Imo, they used "reduced" because as the ball contact point moves up the blade head (from center up), the effective mass is reduced. Or that effective racket mass is less than total racket mass, hence reduced.))

    You tried to compute the speed after impact on mytt. You only used the conservation of momentum formula.
    He used the conservation of momentum, because it holds in any collision, elastic or not. Later on someone copied his calculation and put it to wikipedia :-) Or not. But it is the same.
    Last edited by latej; 10-22-2021 at 01:57 AM.

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    #30
    Quote Originally Posted by latej
    It was interesting to read those posts. Why do you say he didn't explain reduced mass. It was said in there, that it is just the effective mass of the arm/paddle which collides with the ball.
    So approximately what would be the reduced mass?


    They just use the word "reduced", they could have used other word, say "estimated".
    The calculation is simple if you really understand.

    ((Imo, they used "reduced" because as the ball contact point moves up the blade head (from center up), the effective mass is reduced. Or that effective racket mass is less than total racket mass, hence reduced.))
    Does it? Do you know or more importantly, does zeio know?
    What is the equation for reduced mass?

    He used the conservation of momentum, because it holds in any collision, elastic or not. Later on someone copied his calculation and put it to wikipedia :-) Or not. But it is the same.

    Yes, but there is more.

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    #31
    Quote Originally Posted by brokenball
    So approximately what would be the reduced mass?
    Reduced mass is just a term they used. Since it causes so much tension :-), lets use the term effective mass, which they used too, from now on please. In the figures 5 and 6, in zeio's post, you can see the approximate values of the effective mass.

    Something does collide with the ball - what they call the arm/paddle system, it does have some mass. That system is usually connected to the body in the shoulder, so what is its mass? People come up with the term "effective" mass, to mean the mass of it that is relevant for the collision with the ball.

    Does it? Do you know or more importantly, does zeio know?
    What is the equation for reduced mass?
    I don't know how they calculated it. One way would be to measure the mass of the ball, consider it ideal enough, then precisely measure initial and final velocities of the the ball and the arm/paddle system thing (where we take the contact point), then put it to the conservation of momentum, and you get ms = mb * (ub - vb) / (vs - us). (b for ball, s for arm/paddle system). I think this equation zeio did before.

    Yes, but there is more.
    It may be. But it doesn't necesarily make his calculation wrong.

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    #32
    Quote Originally Posted by zeio
    Entropy? What am I saying?

    I can't believe the omniscient engineer wants me to spell it out. Perhaps it's too much to expect from an electrical engineer?

    Diffusion is what makes the sponge lose its airy feel as time goes by. It is also what allows the oil to enter the sponge. Both work by the same mechanism due to entropy, just in opposite direction.

    https://socratic.org/questions/how-d...-and-diffusion


    https://ris.utwente.nl/ws/portalfile..._Zielinska.pdf


    In case all that is still too profound for our omniscient engineer, try this:
    pnachtwey is the tendency for discussion to spontaneously fall out and go from a highly ordered harmonious state to less ordered toxic state.

    Last but not least, rubber under tension is just like glass under tension.

    Entropy is a change to a disorder state. However, you got it wrong again. The gas in the gas pockets will diffuse. However, the pressure will remain equalized. That is what I said above. Zeio is some how implying the pressure in the gas pockets will decrease. That is nonsense as the rubbers I have seen don't come in sealed and pressurized plastic bags. What will happens is that some 'gas' will leave the gas pocket and some 'air' will replace the gas molecules. That is the disorder. However, the pressures will remain constant and equal. Zeio can't get the details right.

    Glass under tension is a different topic altogether. Look up St Rupert's drop. Glass in not springy.
    https://youtu.be/xe-f4gokRBs
    Zeio has yet to say what holds he rubber in tension.
    He has not provided a formula using tension to compute the speed after impact.
    He hasn't explained what mass is being reduced.





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    #33
    Quote Originally Posted by latej
    Reduced mass is just a term they used.
    NO! Reduced mass is a valid term with a specific meaning and a formula.

    Since it causes so much tension :-), lets use the term effective mass, which they used too, from now on please.
    NO!

    In the figures 5 and 6, in zeio's post, you can see the approximate values of the effective mass.
    What is the reduced mass?

    Something does collide with the ball - what they call the arm/paddle system, it does have some mass.
    What is it? What is the formula? This is what zeio has been dodging for 6 years.

    That system is usually connected to the body in the shoulder, so what is its mass? People come up with the term "effective" mass, to mean the mass of it that is relevant for the collision with the ball.
    So what is the reduced mass?

    I don't know how they calculated it. One way would be to measure the mass of the ball, consider it ideal enough, then precisely measure initial and final velocities of the the ball and the arm/paddle system thing (where we take the contact point), then put it to the conservation of momentum, and you get ms = mb * (ub - vb) / (vs - us). (b for ball, s for arm/paddle system). I think this equation zeio did before.
    That is not the equation for reduced mass.

    It may be. But it doesn't necesarily make his calculation wrong.
    On MYTT, zeio calculated the speed of the ball after impact was slower than the paddle. That is definitely wrong.

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    #34
    Quote Originally Posted by brokenball
    Entropy is a change to a disorder state. However, you got it wrong again.
    Entropy is not a change to a disorder state, what do you mean by that? Entropy is a measure of disorder of a state, measure how chaotic is the state.

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    #35
    Quote Originally Posted by brokenball
    NO! Reduced mass is a valid term with a specific meaning and a formula.

    NO!

    What is the reduced mass?

    What is it? What is the formula? This is what zeio has been dodging for 6 years.

    So what is the reduced mass?

    That is not the equation for reduced mass.
    I thought we are discussing within the context of that paper zeio posted. They use the term reduced mass there, they meant effective mass, which they also said. If you have alternate meaning to it, then tell what it is. What's the big deal?

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    #36
    Quote Originally Posted by latej
    Entropy is not a change to a disorder state
    Technically you are right and both zeio and I were sloppy. Entropy is not change but it is always changing which is why so many get sloppy. Do a search on the internet. Most people are sloppy.

    Now, why did zeio use the term entropy for the gas in the air/gas pockets? He was not clear about the result.
    What will happen is that and pressure difference between the cells will equalize if there is a difference but since the rubber don't come if sealed packages they are probably equalized by the time we get them.

    There is so much talk about the pros getting boosted rubbers. Does this mean they get form rubber with higher pressure closed cells? If so, is there a shelf life? I have never seen rubbers in a sealed wrapper with an expiration date.

    Has anybody seen an expiration date?

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    #37
    I am entertained by the many levels of trolling and trolling the trolling that is going on here.

    And since it is semi-harmless, I am going to say, have at it.

    What is the reduced mass in my belly? Oh, maybe I am talking about the increased volume of my abdominal cavity rather than the reduced mass! Potentially, I think there may be increased mass along with the increased volume.
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    #38
    Quote Originally Posted by UpSideDownCarl
    And since it is semi-harmless, I am going to say, have at it.
    Yes, though pity the poor chap who posted the original question in this thread!

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    #39
    Quote Originally Posted by Manto76
    Yes, though pity the poor chap who posted the original question in this thread!
    Who knew the mature members of TTDaily were capable of such depth of discussion!
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    #40
    Some rubbers come in sealed packages. DHS H3 Neo anyone?

    So why is it that most (if not all) ESN tensor rubbers shrink? You glue them on your racket, use them for 2 months then you take it off and they don't fit the racket you took them off of. They don't dome out of the package, they are fairly flat. When you take them off of your racket they don't have a reverse dome either, they are just smaller. If you measure the weight when new and used, used they are several gramms lighter.
    DHS H3N has a reverse dome after a few months if you take it off, but it doesn't shrink.

    Butterfly rubbers don't shrink either in my experience. Actually Japanese made rubbers that I encountered with don't have this property.

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