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A bitcoin ransom entrepreneur

March 25, 2021 Uncategorized , ,

I call the bluff. Let’s see the video!

Hello!                                                                   

Unfortunately, I have some bad news for you.                                                            
Several months ago, I got access to the device you are using to browse the internet.                                                     
Since that time, I have been monitoring your internet activity.                                                            

Being a regular visitor of adult websites, I can confirm that it is you who is responsible for this.
To keep it simple, the websites you visited provided me with access to your data.                                                          

I've uploaded a Trojan horse on the driver basis that updates its signature several times per day, to make it impossible for antivirus to detect it. Additionally, it gives me access to your camera and microphone.                                                  
Moreover, I have backed-up all the data, including photos, social media, chats and contacts.                                                   
Just recently, I came up with an awesome idea to create the video where you cum in one part of the screen, while the video was simultaneously playing on another screen. That was fun!                                                                                   

Rest assured that I can easily send this video to all your contacts with a few clicks, and I assume that you would like to prevent this scenario. )

With that in mind, here is my proposal:  
Transfer the amount equivalent to 1350 USD to my Bitcoin wallet, and I will forget about the entire thing. I will also delete all data and videos permanently. 

In my opinion, this is a somewhat modest price for my work.                                                                
You can figure out how to purchase Bitcoins using search engines like Google or Bing, seeing that it's not very difficult.

My Bitcoin wallet (BTC):                                                           
1Lg6nE6zFaMZHiPTFR9nSwuAL6hzeegToC

You have 48 hours to reply and you should also bear the following in mind:                                                          

It makes no sense to reply me - the address has been generated automatically                                                                      
It makes no sense to complain either, since the letter along with my Bitcoin wallet cannot be tracked.
Everything has been orchestrated precisely.                                                                   

If I ever detect that you mentioned anything about this letter to anyone - the video will be immediately shared, and your contacts will be the first to receive it. Following that, the video will be posted on the web!  

P.S. The time will start once you open this letter. (This program has a built-in timer and special pixel ID - [№78853473])
Good luck and take it easy! It was just bad luck, next time please be careful.   

Hardcover edition of Geometric Algebra for Electrical Engineers.

February 27, 2021 Uncategorized , , , ,

I was invited to Kindle Direct Publishing‘s hardcover beta program, and have made my geometric algebra book available in black and white hardcover.

As always, the PDF, leanpub edition, and latex sources are also available.

I thought that it was too confusing to have color and black-and-white editions of the book (color has a significantly higher printing cost), so I have unpublished the color editions of the book (softcover, and hardcover). There is one copy of the color edition left, and once that is sold, it will show as out of print.

New version of classical mechanics notes

January 1, 2021 Uncategorized , , , , , , , , ,

I’ve posted a new version of my classical mechanics notes compilation.  This version is not yet live on amazon, but you shouldn’t buy a copy of this “book” anyways, as it is horribly rough (if you want a copy, grab the free PDF instead.)  [I am going to buy a copy so that I can continue to edit a paper copy of it, but nobody else should.]

This version includes additional background material on Space Time Algebra (STA), i.e. the geometric algebra name for the Dirac/Clifford-algebra in 3+1 dimensions.  In particular, I’ve added material on reciprocal frames, the gradient and vector derivatives, line and surface integrals and the fundamental theorem for both.  Some of the integration theory content might make sense to move to a different book, but I’ll keep it with the rest of these STA notes for now.

Gauge transformation in the Lorentz force Lagrangian.

November 2, 2020 Uncategorized , , ,

[Click here for a PDF of this post with nicer formatting]

Problem: Lorentz force gauge transformation.

Show that the gauge transformation \( A \rightarrow A + \grad \psi \) applied to the Lorentz force Lagrangian
\begin{equation}\label{eqn:gaugeLorentzSTA:20}
L = \inv{2} m v^2 + q A \cdot v/c,
\end{equation}
does not change the equations of motion.

Answer

The gauge transformed Lagrangian is
\begin{equation}\label{eqn:gaugeLorentzSTA:40}
L = \inv{2} m v^2 + q A \cdot v/c + \frac{q v}{c} \cdot \grad \phi.
\end{equation}
We know that the Lorentz force equations are obtained from the first two terms, so need only consider the effects of the new \( \phi \) dependent term on the action. First observe that
\begin{equation}\label{eqn:gaugeLorentzSTA:60}
v \cdot \grad \phi
=
\frac{dx^\mu}{d\tau} \PD{x^\mu}{\phi}
=
\frac{d \phi}{d\tau}.
\end{equation}
This means that the action is transformed to
\begin{equation}\label{eqn:gaugeLorentzSTA:80}
S
\rightarrow S + \frac{q}{c} \int d\tau \frac{d\phi}{d\tau}
= S + \frac{q}{c} \evalbar{\phi}{\Delta \tau}.
\end{equation}
As the action is evaluated over a fixed interval, the gauge transformation only changes the action by a constant, so the equations of motion are unchanged.

References

Editing a book by tearing out pages!

October 25, 2020 Uncategorized ,

I’ve been editing my classical mechanics notes compilation, which doesn’t yet justify being called a book.  Here’s the editing process in action:

I’ve purged about 120 pages, and wrote 16 new pages (covariant Lagrangian and Lorentz force material) to replace portions of some of the gutted material.  The stack beside the book is about 3/8″ thick of ripped out pages.  I ripped them out so that I could see the remainder more easily.

There’s still a lot to purge and rewrite, but I’m now down to a more manageable 347 pages, which is a good start.  Next up will be the material related to Lagrangian densities for field equations (wave equations, Maxwell’s equation, …)

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