The model of fixed-bed adsorption column

Fluid phase:

PDE:= diff(U(x, tau),tau)+ psi*Theta*diff(U(x, tau),x)-(1/Pe)*psi*Theta*diff(U(x, tau),$(x, 2))=-3*psi*xi*(U(x, tau)-Q/K);

IBC:={U(x, 0) = 0,U(0, tau) = 1+(1/Pe)*(D[1](U))(0, tau),(D[1](U))(1, tau)=0};

Particle:

PDE:= diff(Q(r, tau), tau) = diff(Q(r, tau), $(r, 2))+(2/r)*diff(Q(r, tau),r);

IBC:={Q(r, 0) = 0,(D[1](Q))(0, tau) = 0,(1/K)*(D[1](Q))(1, tau)=xi*(U-Q(1, tau)/K)};

Pe:=0.01:

psi:=6780:

Theta:=3.0:

xi:=10000:

I will really appreciate your help. Thanks in anticipation.

Hi guys,

I'm trying to draw a phase portrait based on a system of differential equations, but executing the DEplot command gives me the response in the title. 

The command I entered is this one :

DEplot(sysdif,[u(t),nu(t)],t=0..50,{[u(0)=0.831,nu(0)=0.7]},linecolor=red,numpoints=1000, thickness=1, u=0.5...1, nu=0.6...1, color=black);

the system of equation is this one :

eqd1 := diff(u(t), t) = u(t)*[-gamma + (rho)/(mu - nu(t)) - delta*u(t) + pii - (tau)/(alpha + epsilon*exp(-beta*((omega-u(t))/(kappa-u(t)))))] ;
eqd2 := diff(nu(t), t) = nu(t)*[(omega-u(t))/(kappa-u(t)) - (tau)/(alpha+epsilon*exp(-beta*((omega-u(t))/(kappa-u(t)))))] ;

the model is calibrated. I understand that maple cannot store a kind of number but even changing the parameters won't help. I've been looking for people with same error message but using solutions provided by forum members don't work. Before getting that error message i did have the one with "vars must be declared as a list ..." so I did :

u:='u' ;

nu:='nu';

but now I have the error  "unable to store  '[HFloat(0.005711776872341132)]' when datatype=float[8]".

Does anybody have an idea of the solution to my problem ?

Thanks for your time,

best regards,

Louis

I'm just using it this way:

with(QDifferenceEquations):
QPochhammer(-1,5,10)

Error, (in QDifferenceEquations:-QPochhammer) wrong type of arguments

Am I doing something terribly wrong???

Hi,

     I'm trying to numerically solve a PDE in Maple for different boundary conditions, however I'm having trouble even getting Maple to numerically solve it for simple boundary conditions.

I have cylindrical coordinates, r, z, theta, and I treat r = r(z, theta) for convenience to plot my solution surface. The initial coundary condition is that at z = epsilon (z = 0 is singular) , r = constant and of course r is periodic in theta. This is just a circle, and the analytical solution is know to be a half-sphere  r = sqrt(R^2 - z^2). I entered my initial boundary conditions into Maple, but it doesn't like the periodic one

IBC := { r(epsilon, theta) = R - epsilon__r,
              r(z, 0) = r(z, 2*Pi) };

pdsolve(
  PDE,
  IBC,
  numeric,
  indepvars = [z, theta],
  time = z,
  range = 0..2*Pi);
Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 2, got 1

I'm not sure how to make this work, and then generalize it to more arbitrary intial slices r(epsilon, theta) = f(theta).

Here's the attached worksheet, ForMaplePrimesSUbmission.mw

Any help is appreciated,

Thanks

I have written some statements in maple and when integrating a vector I encounter an error . whats the problem? the error is:

Error, (in evalf/Ei/taylor) unsupported type of index, 1.

F1 := ScalarMultiply(Phi^%T, f);
F := int(F1, x = 0 .. 1);

which f is exp(x-t) and Phi is a vectror.

Hi all,

I want to define variables with indices, possibly zero. So for example I define mu[01] and mu[10]... 

My problem is that mu[01] automatically becomes mu[1] in Maple's output, so that I could not distinguish it from mu[001]... 

Is there any way to address it?

Thanks 
Manuele

r := sqrt(x^2+y^2+z^2);
divE := diff(e*x/(4*Pi*r^3), x)+diff(e*x/(4*Pi*r^3), y)+diff(e*x/(4*Pi*r^3),z);
simplify(divE);

I want to simplify an expression via simplify();

However since the expression is very long (length(expression)=2713899) Maple is taking too long...So far one hour.

I have already simplified several expressions of a similar kind with lengths of up to 400.000 which worked fine within minutes.

Is there any way to speed up the process. Am I making a mistake?

Thanks in advance

of a square matrix having its entries 1,2,...16? See http://oeis.org/A085000 for info.

I want to plot this contour 4x^2+9y^2=160  onto the same f(x,y)=4x^2+9y^2.  The error I keep getting is

Error, (in plot3d) first argument must be either in standard or parametric form

Thanks

Hi all,

I think the developers should pay attention to this problem.

This simple expression with Threads:-Map executed perfectly on my machine with 8-threaded CPU and 16 GB RAM:

Threads:-Map(proc (i) options operator, arrow; ln(i)/2. end proc, [`$`(1 .. 10^7)]);

But the similar expression with Grid:-Map never be executed:

Grid:-Map(proc (i) options operator, arrow; ln(i)/2. end proc, [`$`(1 .. 10^7)]);

Maple or freezed, or crashed every time. Although the consuming of memory is not reached even 50%.

The similar problem exist for Grid:-Seq too. With `$`(1 .. 3*10^6) Grid:-Map and Grid:-Seq executed normally. With `$`(1 .. 5*10^6) - 50/50. But not with `$`(1 .. 10^7).

Is this a real bug of Grid:-Map and Grid:-Seq ?

Or is exist a way to fix this problem?

Thanks.

Updated:

I got a new error behavior of Grid:-Map in this case instead crash or freeze:

Grid:-Launch(numnodes = 8);

st := time[real](); Grid:-Map(proc (i) options operator, arrow; ln(i)/2. end proc, [`$`(1 .. 10^7)]);

time[real]()-st;

print(`output redirected...`); # input placeholder

`System error, `, "bad id"
2267.482

I hope this helps developers to fix this bug.

I can;t seem to get DSOLVE working.  Will some kindly soul please send me a complete example, starting with an f(x) & clearly documented?   Many thanks.

AB

Suppose I have a file, test.txt, which the content is

2
2 0.0 0.0 0.0
1 0.0 0.0 1.6

I would like to save 

Z:=2;

C[1,1]:=2;C[2,1]:=0.0;C[3,1]:=0.0;C[4,1]:=0.0;

C[1,2]:=1;C[2,2]:=0.0;C[3,2]:=0.0;C[4,2]:=1.6;

However, if I use readdata("...",4), seems it do not work.

Is there any flexible command in maple can readfile with different column? Thank you very much!

Hello,

On my multibody model, I meet a mistake during the simulation which is the following :

"Constraint projection failure at 10s".

1) Do you have a idea on this error message so as to correct the settings for the simulation?

2) I would like to know more about the projection method. If, I'm not wrong, there is not a lot of documentation about the projection method used in Maplesim. 

   a) Does someone have some references (scientific papers) which present the theory used for the projection method in Maplesim?

   b) In ths sense, I would be very interesting about learning the theory of the projection method in order to be able to tune correctly the following options linked to the projection method :

- Projection Iterations
- Projection Tolerance
- Event Projection
- Event Iterations
- Event Hysteresis

Thanks a lot for your help.

Hello,

Is it possible to define the orientation of a body with a matrix transformation ?

I have seen this option for the fixed frame but not for the rigid bodies.

I would like to define the rigid bodies thanks to transformation matrix so as to make some checking.

Thank you for your help.