Creating a logic loop which changes individual vector entries

Hi, I was wondering if it would be possible to create a logic loop for a vector that checks each entry of the vector, and changes it if it does not meet the criteria. Example:

    h = 72;

    tflange = [4/4, 5/4, 6/4, 7/4, 8/4];

    hvec = ones(1,length(tflange))*h;

    twmin = ((hvec-(2*tflange))*36)/(0.4*29000); %A 1x5 vector composed of
    %positive real values less than 1

    i = ones(1,length(tflange))*5;

    while (i/16) < twmin
        i = (ones(1,length(tflange)))+i;
    end

    tweb = i/16;

This will change all entries of the vector, but I need to only change the ones that don't meet the criteria. So if twmin is

[0.2, 0.22, 0.3, 0.32, 0.4]

I want tweb to be

[5/16, 5/16, 5/16, 6/16, 7/16]

not

[7/16, 7/16, 7/16, 7/16, 7/16]

Any help will be greatly appreciated.