A million appreciation from South Korea. You have saved my day ! So catchy and enjoyable explanations !
@zhiwarfirooz4119
4 жыл бұрын
박설bina amazing
@zaidpansare4210
4 жыл бұрын
Being from South Korea you needed to learn from an Indian teacher ? I'm surprised
@chanceusealeena7952
3 жыл бұрын
Jinjao
@anuragpandey7427
3 жыл бұрын
@@zaidpansare4210 😑😑😑
@aditit306
2 жыл бұрын
@@zaidpansare4210 bruh😑😑
@your_name_here2158
4 жыл бұрын
The lower the temperature of solidification the smaller the critical r.
@mech-www7563
5 жыл бұрын
sir how to start nucleation????
@nainamkapil3911
4 жыл бұрын
when temperature is less than Tm certain number of atoms assemble together to form solid mass of radius = critical radius, nucleus form.
@dr.m.dhavamurthy4599
5 жыл бұрын
sir, such an amazing lecture; I really impressed by your way of presentation. It was too difficult to understand when I was doing Ph.D. Now it is given a great impact to enhance my skill in the research field. Thank you very much for your great lecture.
@suriyaprakash8663
3 жыл бұрын
Sir what is the scope of phd in materials in india?
@rajibdas1087
6 жыл бұрын
Sir , ur way of teaching is superb. U have made this subject so interesting.
@vincemaz
4 жыл бұрын
Sir i am a Msc student in Tu Delft (Netherlands) and your videos help me a lot for many different courses. Thank you verymuch i love the way you make concepts easy to understand
@nagasai4328
4 жыл бұрын
Why does a ball of critical radius form in first place since its delta Gf is positive? Why is critical radius not when delta Gf = 0 but when it is maximum?
@introductiontomaterialsscience
4 жыл бұрын
You have asked a very serious and interesting question. In fact, in this regigon thermodynamics breaks down!! The formation of nuclei can only be explained by statistical fluctuations of atoms which is beyond thermodynamics :-( We are essentially cheating by applying thermodynamics such small systems.
@panchananmajee7465
3 жыл бұрын
@@introductiontomaterialsscience Does the result by applying thermodynamics satisfy the result of statistical fluctuations of atom?
@SujoyShivde
4 жыл бұрын
This was beautiful. Wish we were taught like this the first time round.
@minason2823
4 жыл бұрын
Sir, I have one quick question. Why is γ(gamma) always positive? Is it because we use/need energy to create that solid-liquid interface?
@prashantss8899
3 жыл бұрын
sir if radius is just above r* still the term is positive then how does the nucleation start
@nitinkumarmishra2211
2 жыл бұрын
same doubt
@messimagic2527
3 жыл бұрын
Respected sir, how does viscosity affect the nucleation rate in pure metal?
@kishoresadasivan5329
3 жыл бұрын
Soft words filled with knowledge. dear Sir.thanks.
@joshebramjoseph2954
4 ай бұрын
how can liquid exist below its freezing temperature i mean by that time everything would have been converted solid itself right how will nucleation occur below Tm as what i understood was freezing will occur till complete liquid changes to solid and until then T will remain constant at Tm
@introductiontomaterialsscience
3 ай бұрын
What you are stating is the condition of equilibrium solidification where the entire solidification can happen at the melting point. But this requires an extremely slow cooling. If you cool rapidly it is possible to retain liquid, for some time, in metastable state below the meting point before it starts freezing.
@hanikorek5567
4 жыл бұрын
amazing ! i think a school student would understand such lecture.. i lost my time yesterday trying to understand these concepts during my PhD study this video illustrates everything and answers all of my questions. ThankYou!
@TheMsnitish
4 жыл бұрын
are you from Turkey ?
@pgseries
3 жыл бұрын
Thank you Prof. Rajesh Prasad, highly appreciate, your lecture help me understanding nucleation thermodynamically.
@sandeeprajbhar1919
5 жыл бұрын
thanks sir! for providing such a great lecture
@dimbanimvula3672
7 ай бұрын
U are the best teacher ever for material science
@सागरबड़थ्वाल
9 ай бұрын
splendid lecture sir
@monishreddy1797
4 жыл бұрын
Sir..earlier in the lecture you said if del(G) is negative then the reaction is feasible/spontaneous...but at 19:38 we are seeing if del(G) is increasing or decreasing..that is we are seeing if del(del(G)) is positive or negative..why are we considering that..also at r* del(G) is positive..so reaction should not be spontaneous..shouldn't we be considering the point where del(G) becomes zero..that is the x-intercept of curve..please correct me if iam wrong
@introductiontomaterialsscience
4 жыл бұрын
Please see my reply to Naga Sai who has also asked the same question.
@monishreddy1797
4 жыл бұрын
@@introductiontomaterialsscience thank you sir
@ThatOneGuy0631
2 жыл бұрын
Thank you for this explanation.
@hariprasadvp4866
4 жыл бұрын
A huge thanks and gratitude!
@numankashif6158
Жыл бұрын
Can anyone tell me it mean we have to give energy to make critical size radius and what type of energy is given
@sampathvinay2920
Жыл бұрын
If u know telugu , then like ❤️ you made the material science subject easy
@smarajitpunaykanti6463
2 жыл бұрын
Your teaching reminds me of my private college days . It sucks . Thanks Prof .🙏
@thangabharathi.t9720
4 жыл бұрын
Sir, How this is possible for a cylindrical nuclei? It involves critical height and critical radius.
@motiontv3621
3 жыл бұрын
Can I get summer internship in IIT Delhi as I'm from NIT Rourkela.
@suriyaprakash8663
3 жыл бұрын
Sir what is the significance of r* ? Does r* say anything about phase transformation time or grain size
@punitkumarsoni7092
6 жыл бұрын
👌👌👌👌👌
@BadalKumar-ee9xh
Жыл бұрын
Good Evening Sir , Sir at 29:39 you told Driving force is inversely proportional to Radius, but will the negative sign will not influence the result
@introductiontomaterialsscience
Жыл бұрын
The negative sign in the expression of radius makes it positive because the denominator (Gs-GL) is negative.
@shashwatchaurasia2693
3 жыл бұрын
love from India
@shashwatchaurasia2693
3 жыл бұрын
watch at 1.25x
@mosstaqueahamed8289
3 жыл бұрын
Very fruitful lecture sir.
@dimbanimvula3672
7 ай бұрын
U are the best teacher ever for material science
@evansmichelo883
2 жыл бұрын
During the calculation of critical radius, is the temperature supposed to be all converted to kelvins?
@rajeshprasadlectures
2 жыл бұрын
Yes, like in any thermodynamic calculations.
@dharmendersinghrana5652
2 жыл бұрын
Impressive presentation. Thank you Sir
@limon5312
3 жыл бұрын
Love from Dpt of MSE,Ruet..😷
@masoudfaraj3647
4 жыл бұрын
why a proeutectoid phase (ferrite or cementite) forms along austenite grain boundaries
@rajeshprasadlectures
4 жыл бұрын
This is what is termed as heterogeneous nucleation. If the ferrite nucleus forms inside the austenite grain (homogeneous nucleation) then only new ferrite/austenite interfaces form. This happens also in heterogeneous nucleation of ferrite on austenite/austenite grain boundaries. But in this case original austenite/austenite grain boundaries disappear. This leads to a release in energy making the heterogeneous nucleation favourable.
@kasinfo509
3 жыл бұрын
Thank you so much sir. clear and detail lecturing.
@aniketsaw6049
3 жыл бұрын
Sir in previous lecture you told dT= (Tm- T ). But in this lecture at last you write dT = (T-Tm) why ??
@rajeshprasadlectures
3 жыл бұрын
Sorry for the confusion. You can define it in either way. But one has to take care of the sign. So below the melting point, T
@aniketsaw6049
3 жыл бұрын
@@rajeshprasadlectures thank you so much sir 🙏
@openargument5285
4 жыл бұрын
Sir we are converting liquid to solid, so solid is product and in free energy expression, should it be GL - Gs?
@introductiontomaterialsscience
4 жыл бұрын
We define DG=G_final-G_initial. Thus for L->S it is Gs-GL.
@openargument5285
4 жыл бұрын
@@introductiontomaterialsscience thanks
@beena3353
2 жыл бұрын
Best lecture I have seen so far
@shradhajuneja876
10 ай бұрын
Thankyou so much sir
@NITian_Shourya
10 ай бұрын
5:33 😮
@TheChosendBeats
8 ай бұрын
3:13
@mdnazmulhuda5647
3 жыл бұрын
Just Amazing.
@keraroberts3610
3 жыл бұрын
Life saver
@rajulinga6298
3 жыл бұрын
Sir, what is mean by undercooling?
@rajulinga6298
3 жыл бұрын
I mean what is mean undercooled liquid?
@introductiontomaterialsscience
3 жыл бұрын
@@rajulinga6298 If a liquid remains as liquid below its equilibrium freezing point it is called an undercooled liquid.
@hamza_ME_
4 жыл бұрын
AMAZING AMAZING AMAZING...
@ibrahimyldrm2427
4 жыл бұрын
absolutely sensational
@ahsansaeed4823
4 жыл бұрын
thnx sir
@priyanshusinha1209
4 жыл бұрын
Sir does nucleation will take place if r=r*??
@rajeshprasad101
4 жыл бұрын
Well, the situation of r=r* is critical, that's why it is called the critical radius. If a few atoms join the particle with r=r* it will grow. If few atoms leave it then it will dissolve. So it is in unstable equilibrium.
@priyanshusinha1209
4 жыл бұрын
@@rajeshprasad101 Thank u so much sir..
@rajeshprasad101
4 жыл бұрын
@@priyanshusinha1209 I just edited metastable to unstable in my answer.
@simonghostriley88
5 жыл бұрын
Sir, in the previous lecture you said undercooling is Tm - T and in this lecture you wrote undercooling is T - Tm. Is it wrong or both these have same undercooling values ?
@hariprasath2529
5 жыл бұрын
Tm-T is correct check It in textbook
@ayush7805
4 жыл бұрын
yeah, he made a silly mistake in this video. It was correct in the previous one. He rarely makes mistakes
@deepkalariya6906
3 жыл бұрын
It's for signing purpose T - Tm
@d225mohdahsan8
2 жыл бұрын
@@ayush7805 he didn't made silly mistake Make sure uh r perfect 😂😂😂😂
@Abhijeetkumar314
4 жыл бұрын
super ❤️️
@harshpatelhp9439
3 жыл бұрын
Sir please explain in hindi for..... Weak student
@pailasaisravan5423
4 жыл бұрын
sir at 19.26 , why it is not thermodynamically favourible situation ?? and as r less than r* you said thermodynamically growth is not possible and i would like to know the reason from that point of view
@introductiontomaterialsscience
4 жыл бұрын
Because if you allow a particle with r
@pathlavathganesh5055
5 жыл бұрын
sir,what is r* here?
@pathlavathganesh5055
5 жыл бұрын
How to find it?
@nikhilakalia9692
4 жыл бұрын
r* is the critical radius of the spherical surface which is needed for nucleation
@nainamkapil3911
4 жыл бұрын
@@pathlavathganesh5055 r*= -2γ/[Gs-Gl] he has derived this expression.
Пікірлер: 96