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# Engineering Science - Science topic

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Questions related to Engineering Science

U-slip is used to calculate the drag coefficient in EMMS/bubbling model. But there are three different slip velocities in the model. I do not know which one should be chosen here. And my calculation results are a little bit different from the references.

The references I used are as follow:

[1]HONG K, SHI Z, WANG W, et al. A structure-dependent multi-fluid model (SFM) for heterogeneous gas–solid flow [J]. Chemical Engineering Science, 2013, 99: 191-202.

[2]SHI Z, WANG W, LI J. A bubble-based EMMS model for gas–solid bubbling fluidization [J]. Chemical Engineering Science, 2011, 66(22): 5541-55.

I am a Professor of a university which is having its campuses in different parts of the globe and there are many professors in different fields. We are all taking various faculty development programmes across different domains of Engineering, science. Most of this technical certifications are of very high order. However with research and teaching being part of our curriculum I would like to ask you to suggest a few online course which can be done for ABET and other accreditation and useful for the education industry point of work since I have to continue my work as a professor and it will involve gradation also.

Dear all,

I have submitted the manuscript in

**Journal of Engineering Science and Technology Review****(JESTR)**since 10 months ago.I have tried to send email to the editor many times, but there is no any responses.

Therefore, I would like to withdraw my manuscript since I am not sure whether the journal is still active or not.

The submission system is a bit poor, there is no option to withdraw the manuscript .

Could any one give please me an advise about this situation?

Thank you,

KM

In Engineering, Science, and Fluid Dynamics, there are many unitless numbers very useful for effective simulation. However, is there any parameter you analyze recently and you just appreciate your observation?

Which dimensionless parameter have you analyzed and deeply appreciate it's significance?

Hi Everyone. Please suggest me the SCI journals list which don't contains article processing charges.

Greeting to all.

Drear researcher,

I am working with the conference organizing committee as publication head. It is a multidisciplinary conference on Engineering, Science, and Humanity. How and what is the best way to collaborate with Scopus indexed journals in different areas. I need your assistance.

Thanks in Advance

Best Regards.

European countries produce frequently research based PhDs, in Germany they call it Dr-Ing. for example. I am looking for Universities in US who are doing similar in STEM area, i.e. capable to produce Doctor of Engineering, it's DEng, or DSc (Engineering or Science) or similar. MIT has prestigious DSc for example.

Thanks, Teddy Ivanitzki

A lot people in

Computer Science

Management Science

Engineering Sciences

are leaving Pakistan and moving abroad?

What are main reasons and is the same happening in INDIA, BANGLADESH etc

Our journal (International Journal of BIM and Engineering Science) publish by BIMarabia. Just have one volume and one issue. We want to rapidly get top ranked and high impact factor. Kindly please, your advice to achieve this goal.

Someone advised me that we should have much indexing. Kindly please, can you advise us how can we get index in the most important sites to achieve our goal as soon as possible.

Hello,

I am looking for suggestions how to improve and better evaluate a nonlinear regression model for the differential equation of the reaction rates of DME Synthesis. This are the main results ( more information on the set-up below):

The results indicate that all kinetik Arrhenius factors kTr tend towards zero, as well as the Adsorption constants K_tr,CO2 and H2 and deltaH_ads,CO.

The confidence intervals for the Adsorption coefficients and enthalpy of CO2 and H2 are extremely large and include zero, leading to a lack of statistical significance. T

he Parameter Covariance Matrix suggests correalation between kMeOH and K_trCO, kMeOH and K_trH2, k3 and activation Energy E_an_WGS, E_anMeOH and H_adsCO and -CO2, as well as between the Adsorption constants K_trCO and K_trH2 and ads. enthalpies H_adsCO and H2.

I therefore wanted to ask:

- Is there any statistical interference /hypothesis tests, similar to the F-test for a complete linear regression model, which I could use for reparametrization?
- How would you check for colinearity between the parameters?
- You know of any methods for detecting outliers in the data-set for non-linear regression?
- Is there any toolbox / open-source code or literature in Matlab for implementing bayesian regression techniques for ODE models?
- You think the matlab function nlparci is a good tool for calculating confidence intervals for such a model?
- Any other suggestions for improving / testing the model
- I was thinking therefore of somehow replacing the adsorption constants by one general term for all three, but I dont have a concrete idea yet. I was also surprisded that the Arrhenius factors tend towards zero.
- Perhaps I should also remodel the Temperature dependency of the Arrhenius factor
- Would you consider trying a Bayesian regression approach in order to reduce the number of parameters?

Setup:

I am considering experimental data a collegue has made based on the following DME network:

CO2 + 3H2 <-->CH3OH + H2O MeOH

2CH3OH <--> CH3OCH3 + H2O DME

CO + H2O <--> CO2 + H2 WGS

She has fitted parameters for the results of catalyzed fulid bed reactor with the reaction rate model of Lu (Simulation and experiment study of dimethyl ether synthesis from syngas in a

uidized-bed reactor. Chemical Engineering Science) 59(22-23):5455{5464, 2004).

The reaction rates contain an Arrhenius factor ki, Fugacities, Equilibrium Constant Kfi in terms of pressure and the Adsorption constant Ksubstance. The equations are are in the appendix.

She had approximately 240 experiments varying in inlet concentration, Temperature and volume flow. The estimation was done with matlab lsqnonlin, solving a basic PFR Model with the Ordinary Differential equation

dy/dz = RTZ / (up) * (-y sum_komponent_reaction(stochiometric koef.*r_reaction) + sum_reaction(stochiometric koef*r_reaction).

Best,

Dennis

There are many types of chaotic maps and we want to study relationship between them. Our aim is to find which type implies the other or in other word, which one is stronger than the other.For hint: see New Concepts of Alpha-Chaotic Maps - Journal of Multidisciplinary Engineering Science and Technology (JMEST)

ISSN: 3159-0040 - Vol. 2 Issue 2, February - 2015

I'm trying to validate the method of calculation of exergy. I would like to compare the results of my calculations with example from Hinderink, A. P., F. P. J. M. Kerkhof, A. B. K. Lie, J. De Swaan Arons, and H. J. Van Der Kooi. “Exergy Analysis with a Flowsheeting simulator—I. Theory; Calculating Exergies of Material Streams.” Chemical Engineering Science 51, no. 20 (October 1996): 4693–4700. doi:10.1016/0009-2509(96)00220-5.

Which is interesting because the stream is gaseous in actual and mixed phase in reference conditions.

I used simulator to calculate enthalpy and exergy in actual and reference conditions. Below are the values from simulator. Actual conditions are 150degC, 101325Pa and composition as below. Reference conditions 25degC, 101325 Pa

Stream Actual conditions Reference conditions

kmol/s Mol Frac kmol/s Mol Frac

Water 0,22 0,22 0,22 0,22

Carbon Dioxide 0,02 0,02 0,02 0,02

Carbon Monoxide 0,01 0,01 0,01 0,01

Nitrogen 0,75 0,75 0,75 0,75

Nitric Oxide 0,01 0,01 0,01 0,01

** Total Flow 1,00 1,00

Frac Vapor 1,00 0,81

Molec Wt 26,14 26,14

Temperature Kelvin 423,15 298,15

Pressure Pa 101325,00 101325,00

Mass Flow kg/s 26,14 26,14

Enthalpy J/kmol 3801830,20 -8568429,40

Entropy J/kmol-K 16301,26 -26524,05

So first column are actual conditions of gas, and second column are reference conditions:

I calculate:

Ex_ph = h-h0 - T0*(s-s0) and i get the result Ex_ph = -398kW

which is completely different than mentioned source, which claims the Ex_ph to be 2532kW.

What is wrong with my calculation? Or maybe something is wrong with enthalpy or entropy of the stream?

Regards,

Marcin

Hi Im trying to combine Actuator disk theory with CFD.

I found two options

Either to add source term to momentum equation or use pressure jump boundary condition. (fan boundary).

Can anyone explain me of this

Literatures suggest that positive polarity is commonly used for Macro level EDM process and negative polarity for micro EDM.

What is the basic reason behind this?

when I clicked the run button, the system shows

The matrix is not strictly diagonally dominant at row 1

The matrix is not strictly diagonally dominant at row 2

The matrix is not strictly diagonally dominant at row 3

The matrix is not strictly diagonally dominant at row 4

What dose this mean?? what's the matter with my input??

clear;clc

format compact

%% Read or Input any square Matrix

A = [-8.7673 9.4736 0 0 0;

4.7368 -8.4736 4.7368 0 0;

0 4.7368 -8.4736 4.7368 0;

0 0 4.7368 -8.4736 4.7368;

0 0 0 -9.4736 10.4736];% coefficients matrix

C = [20;20;20;20;20];% constants vector

n = length(C);

X = zeros(n,1);

Error_eval = ones(n,1);

%% Check if the matrix A is diagonally dominant

for i = 1:n

j = 1:n;

j(i) = [];

B = abs(A(i,j));

Check(i) = abs(A(i,i)) - sum(B); % Is the diagonal value greater than the remaining row values combined?

if Check(i) < 0

fprintf('The matrix is not strictly diagonally dominant at row %2i\n\n',i)

end

end

%% Start the Iterative method

iteration = 0;

while max(Error_eval) > 0.001

iteration = iteration + 1;

Z = X; % save current values to calculate error later

for i = 1:n

j = 1:n; % define an array of the coefficients' elements

j(i) = []; % eliminate the unknow's coefficient from the remaining coefficients

Xtemp = X; % copy the unknows to a new variable

Xtemp(i) = []; % eliminate the unknown under question from the set of values

X(i) = (C(i) - sum(A(i,j) * Xtemp)) / A(i,i);

end

Xsolution(:,iteration) = X;

Error_eval = sqrt((X - Z).^2);

end

%% Display Results

GaussSeidelTable = [1:iteration;Xsolution]'

MaTrIx = [A X C]