# How do I store data in multiple loops?

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So I have the task to solve a system of equations over a range of temperatures and a range of volumes. From this, I am supposed to make surface plots of my results. The problem is, I can only get one of my loops to output it's proper range of data, because I do not know how to get matlab to store the data from the loops in a matrix, instead of creating one long vector. If anyone could help, that would be wonderful. Thanks

%this first section is just constants the equations need to run

mdot=1; %L/min

A=2; %2mol/L concen A

E=1; %mol/L concen Enzyme

%therefore molar flow rate is 2 mol/min in and out

ndot=2;

%knb=kb-1, ktb=kb2

kb=0.4;

knb=0.03;

ktb=0.005;

kc=0.05;

knc=0.045;

ktc=0.03;

KMB=(knb+ktb)/kb;

KMC=(knc+ktc)/kc;

v=20;

x1=[];

x2=[];

x3=[];

x4=[]; %this is just to check the total mol balance

%Out of the cstr

x5=[];

xa=[];

xb=[];

xc=[];

xd=[];

xf=[];

xg=[];

xUU=[];

%VCSTR 20->500 L

DH1=9000; %in J/mol

DG1=-10000;

DH2=-15000;

DG2=500;

DH3=30000;

DG3=500;

P=0.5;

R=8.314;

spaces=24;

n=((500-20)/spaces)+1;

J=linspace(20,500,n);

T=273

%so here is the problem. I need to run temperature from 273 to 423.

%However when I try to loop temperatures, it spits out all of my x values linearly instead of in a grid.

for i=1:1

Lk1=(-1/R)*(((DG1-DH1)/298)+(DH1/T));

k1=exp(Lk1)

Lk2=(-1/R)*(((DG2-DH2)/298)+(DH2/T));

k2=exp(Lk2)

Lk3=(-1/R)*(((DG3-DH3)/298)+(DH3/T));

k3=exp(Lk3)

%y(1)=a y(2)=b y(3)=c y(4)=d y(5)=f y(6)=G y(7)=Z1 y(8)=Z2 y(9)=Z3

for w=1:length(J)

fun=@(x)ndot-x-(ktb*E*x/(x+KMB*mdot))*v-(ktc*E*x/(x+KMC*mdot))*v;

x0=1;

[x]=fsolve(fun,x0); %A

v=v+spaces;

xtwo=(ktb*E*x/(x+KMB*mdot))*v; %B

xthree=(ktc*E*x/(x+KMC*mdot))*v; %C

xfour=[x]+xtwo+xthree; %Checks that CSTR moles stay the same

Eqsys=@(y)[(k1*(y(1)^2)*y(2)*y(3))-((y(4)^3)),

(k2*y(1)*y(2))-(y(3)*(y(5)^3)*(P^2)),

(k3*P*y(1)*y(2))-y(6),

([x]-2*y(7)-y(8)-y(9)-y(1)),

(xtwo-y(7)-y(8)-y(2)),

(xthree-y(7)+y(8)-y(9)-y(3)),

((3*y(7))-y(4)),

((3*y(8))-y(5)),

(y(9)-y(6))];

b=[1,1,1,1,1,1,1,1,1];

q=fsolve(Eqsys,b);

x1=[x1;[x]]; %A range of vol

x2=[x2 xtwo]; %B ''

x3=[x3 xthree]; %c"

x4=[x4 xfour];

x5=[x5;q];

xa=[xa;q(:,1)];

xb=[xb;q(:,2)];

xc=[xc;q(:,3)];

xd=[xd;q(:,4)];

xf=[xf;q(:,5)];

xg=[xg;q(:,6)];

end

T=T+(150/(n));

end

% so if anyone can get the values to run from v=20 to 500 and T=273 to 423, that would be wonderful. Thanks

### Answers (1)

Roman Müller-Hainbach
on 2 Nov 2017

##### 0 Comments

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