Advanced Search

Samir Khan

1971 Reputation

20 Badges

16 years, 193 days
Contact Samir Khan

My role is to help customers better exploit our tools. I’ve worked in selling, supporting and marketing maths and simulation software for all my professional career.

I’m fascinated by the full breadth and range of application of Maple. From financial mathematics and engineering to probability and calculus, I’m always impressed by what our users do with our tools.

However much I strenuously deny it, I’m a geek at heart. My first encounter with Maple was as an undergraduate when I used it to symbolically solve the differential equations that described the heat transfer in a series of stirred tanks. My colleagues brute-forced the problem with a numerical solution in Fortran (but they got the marks because that was the point of the course). I’ve since dramatized the process in a worksheet, and never fail to bore people with the story behind it.

I was born, raised and spent my formative years in England’s second city, Birmingham. I graduated with a degree in Chemical Engineering from The University of Nottingham, and after completing a PhD in Fluid Dynamics at Herriot-Watt University in Edinburgh, I started working for Adept Scientific – Maplesoft’s partner in the UK.

MaplePrimes Activity


These are replies submitted by Samir Khan

@Markiyan Hirnyk The data comes from htt...

Samir Khan 1971
July 01 2017

@Markiyan Hirnyk The data comes from http://data.uis.unesco.org/Index.aspx?queryid=166. Specifically, it's the adult literacy rate for both sexes, ages 15+. The complete application is here

@Ramakrishnan The Organic Rankine Cycle ...

Samir Khan 1971
June 30 2017

@Ramakrishnan The Organic Rankine Cycle application can be found here (and it's in the Application Gallery in Maple 2017). All the code is in the startup code region. In the application

  • the flowchart is an image (that is, an image file created in another tool and placed on the plot with the background option)
  • the text and numbers on the plot are textplots.

If you want box color to vary with the value of a variable, you'll need to construct the flowchart (i.e the boxes and the arrows) using plottools. Perhaps something like this

with(plottools):
with(ColorTools):
with(plots):
conditionalValue := 1.2:
colorList := [[0,79/255, 121/255], [221/255,231/255, 240/255]]:
colorValue := piecewise(conditionalValue > 1, colorList[1], colorList[2]):
p1:=rectangle([-2,1],[2,-1],color=Color("RGB",colorValue), style=surface):
p2 := textplot([2,1.4,sprintf("Value = %.1f",conditionalValue)],font=[Arial, Bold]):
display(p1, p2,scaling=constrained, view = [-5..5, -5..5], axes = none)

 

PDE enhancements...

Samir Khan 1971
May 28 2017

@Ramakrishnan You might be interested in this document:

Enhancements to PDE solvers in Maple 2017

@Markiyan Hirnyk We already know :)...

Samir Khan 1971
May 26 2017
0 0

@Markiyan Hirnyk We already know :)

Send us one of your Mathcad worksheets...

Samir Khan 1971
December 06 2016
0 0

Stefan

Please send one of your Mathcad worksheets to us at support@maplesoft.com (mark it for my attention)

I'll let you know if we think Maple is a viable alternative.

Samir

@mclaine Could you please email us a Mat...

Samir Khan 1971
October 12 2016
0 0

@mclaine Could you please email a typical Mathcad worksheet to support@maplesoft.com (marked for my attention). I'd like to take a closer look, and perhaps provide a few recommendations. The technical context always matters

Mathcad will discard angle units in nume...

Samir Khan 1971
October 11 2016
0 0

Mathcad will discard angle units in numeric output...

Maple will not, unless you specifically ask it to (with convert(B,unit_free))

If you're thinking about switching from Mathcad to Maple, I would not concentrate on directly reproducing your Mathcad units experience in Maple. The underlying implementation is too different.

Are you doing antenna design? I'm guessing from your previous questions and comments about units, scientific constants, and phasors.

@mclaine I used to work for a Mathcad re...

Samir Khan 1971
October 11 2016
0 9

@mclaine I used to work for a Mathcad reseller in tech support, so I know both products well.

Are you attemping to convert an existing Mathcad worksheet to Maple? If so, can you share the Mathcad worksheet? That would help us understand the context of your issue.

Cooling Potential of a Zeer...

Samir Khan 1971
June 24 2016

@Christopher2222 Here's a rough cut of an analysis.

 

> 

with(ThermophysicalData):
with(plots):


This function gives the coldest possible temperature (i.e. the wet bulb temperature) in a Zeer as a function of the air temperature

and the relative humidity

> 

Twb_val := (Tdb_val, R_val) -> Property(Twb, HumidAir, Tdb = Tdb_val, R = R_val,

pressure = 101325):


Range of relative humidities to plot:

> 

R_val := [0.3, 0.4, 0.5, 0.6, 0.7]:
> 

p1 := seq(plot(Twb_val(temp, R_val[i]), temp = 280 .. 310, adaptive = false,

numpoints = 20), i = 1 .. 5):
> 

p2 := seq(textplot([310, Twb_val(310, R_val[i]), sprintf("R = %.1f",R_val[i])]),

i = 1 .. 5):
> 

display(p1, p2, labels = ["Air Temperature (K)", "Coldest Possible Temperature in Zeer (K)"],

labeldirections = [horizontal, vertical])

 

At a constant air temperature, the coldest possible temperature (i.e. the wet bulb temperature) increases as the relative humidity

(i.e. water in air) increases.

 

This makes sense because

• 

If there is more water in the air, less water will evaporate from the wet sand between the two pots in the Zeer

• 

and hence less latent heat will be removed


Download Zeer.mw

Modelica custom component that reads the...

Samir Khan 1971
February 05 2016

@Pieter 

This MapleSim model contains a Modelica custom component that reads the CoolProp DLL. You'll need to change the path in the code to point to the location of the DLL on your computer.

ExternalCCodeCalls.msim

Samir

@Thomas Richard Those techniques are no...

Samir Khan 1971
November 02 2015

@Thomas Richard

  • Those techniques are not appropriate for the typical home user (e.g. ISPs that block port 25, Windows OS etc)
  • MailGun works also on the MapleCloud. I have Cloud applications that email results to the user (after the user has entered their email in a text area). Let me know if you want access.

 

@Axel Vogt  Here's the full email h...

Samir Khan 1971
October 30 2015

@Axel Vogt 

Here's the full email header

Mailgun_email_header.txt

The header of Sample.txt implies that th...

Samir Khan 1971
April 02 2015
0 0

The header of Sample.txt implies that the data is generated by an oscilliscope. 

Can your oscilloscope generate binary data files? Then you could attempt to use ?FileTools[Binary] to import the data.

Fonts...

Samir Khan 1971
April 08 2014
0 0

In addition to the other responses, I find that changing the default 2D math font from Times New Roman to a sans-serif font (like Calibri or equivalent) helps with clarity.

@madruga1155 Right now, viscosity i...

Samir Khan 1971
September 29 2012

@madruga1155 Right now, viscosity is taken into account when calculating the friction factor (i.e. viscosity is used to calculate the Reynolds number, and the Reynolds number is used to calculate the friction factor).

You could also model non-Newtonian or power law liquids etc. This would need a new pipe model (not difficult) with equations describing the viscosity / bulk shear rate relationship.

4 5 6 7 8 Page 6 of 8