| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next

C[omp]ute

Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

Last 100 entries

Flexible Muscle-Based Locomotion for Bipedal Creatures; SQL Performance Explained; The Little Manual of API Design; Multiple Word Sizes; CRC - Next Steps; FizzBuzz; Update on CRCs; Decent Links / Discussion Community; Automated Reasoning About LLVM Optimizations and Undefined Behavior; A Painless Guide To CRC Error Detection Algorithms; Tests in Julia; Dave Eggers: what's so funny about peace, love and Starship?; Cello - High Level C Programming; autoreconf needs tar; Will Self Goes To Heathrow; Top 5 BioInformatics Papers; Vasovagal Response; Good Food in Vina; Chilean Drug Criminals Use Subsitution Cipher; Adrenaline; Stiglitz on the Impact of Technology; Why Not; How I Am 5; Lenovo X240 OpenSuse 13.1; NSA and GCHQ - Psychological Trolls; Finite Fields in Julia (Defining Your Own Number Type); Julian Assange; Starting Qemu on OpenSuse; Noisy GAs/TMs; Venezuela; Reinstalling GRUB with EFI; Instructions For Disabling KDE Indexing; Evolving Speakers; Changing Salt Size in Simple Crypt 3.0.0; Logarithmic Map (Moved); More Info; Words Found in Voynich Manuscript; An Inventory Of 3D Space-Filling Curves; Foxes Using Magnetic Fields To Hunt; 5 Rounds RC5 No Rotation; JP Morgan and Madoff; Ori - Secure, Distributed File System; Physical Unclonable Functions (PUFs); Prejudice on Reddit; Recursion OK; Optimizing Julia Code; Cash Handouts in Brazil; Couple Nice Music Videos; It Also Works!; Adaptive Plaintext; It Works!; RC5 Without Rotation (2); 8 Years...; Attack Against Encrypted Linux Disks; Pushing Back On NSA At IETF; Summary of Experimental Ethics; Very Good Talk On Security, Snowden; Locusts are Grasshoppers!; Vagrant (OpenSuse and IDEs); Interesting Take On Mandela's Context; Haskell Cabal O(n^2) / O(n) Fix; How I Am 4; Chilean Charity Supporting Women; Doing SSH right; Festival of Urban Intervention; Neat Idea - Wormholes Provide Entanglement; And a Link....; Simple Encryption for Python 2.7; OpenSuse 13.1 Is Better!; Little Gain...; More Details on Technofull Damage; Palmrest Cracked Too....; Tecnofull (Lenovo Support) Is Fucking Useless; The Neuroscientist Who Discovered He Was a Psychopath; Interpolating Polynomials; Bottlehead Crack as Pre-amp; Ooops K702!; Bottlehead Crack, AKG K701; Breaking RC5 Without Rotation; Great post thank you; Big Balls of Mud; Phabricator - Tools for working together; Amazing Julia RC5 Code Parameterized By Word Size; Chi-Square Can Be Two-Sided; Why Do Brits Accept Surveillance?; Statistics Done Wrong; Mesas Trape from Bravo; European Report on Crypto Primitives and Protocols; Interesting Omissions; Oryx And Crake (Margaret Atwood); Music and Theory; My Arduino Programs; Elliptic Curve Crypto; Re: Licensing Interpreted Code; Licensing Interpreted Code; ASUS 1015E-DS03 OpenSuse 12.3 SSD; translating lettuce feature files into stub steps files; Re: translating lettuce feature files into stub steps files; A Tale of Two Psychiatrists; The Real Reason the Poor Go Without Bank Accounts; The Rational Choices of Crack Addicts

© 2006-2013 Andrew Cooke (site) / post authors (content).

Nuclear Enrichment Technology

From: "andrew cooke" <andrew@...>

Date: Mon, 29 Dec 2008 20:15:12 -0300 (CLST)

While reading around about the Iranian enrichment plant at Naratz I
started wondering about the design of the centrifuges.  I had always
assumed that they would have a large radius (like, several meters)
(centrifugal force is proportional to omega^2 * radius, where omega is the
rotational velocity).

In fact it's quite possible to reach the physical limits of the materials
involved at just a few cm (10cm radius in Iran, I think) by using
sufficiently high rotation speeds.  Things are more complicated, because
what is being optimised isn't separation by one "small" rotor, but total
throughput in a cascade.  So it appears that the optimum design is a
vertical rotation axis, with a tall rotor and the physical limit to
rotation speed seems to be related to resonance (in a vertical mode)
rather than simple tensile strength (a centrifuge designed to operate
above the lowest resonant frequency - there are other modes at higher
frequency of course - is called "super-critical").

It's still not clear to me why it's not better to make more, shorter
centrifuges that have higher critical frequencies.  Part of the issue may
be costs associated with bearings and motors (which are per centrifuge and
so get cheaper with length).

Anyway, there's a very details report here -
http://www.pnl.gov/main/publications/external/technical_reports/PNNL-14480.pdf

One thing that surprised me was Argentina's appearance in the lists of
countries developing technologies.  I assume that was linked to the
military regime?  Scary local politics.

Andrew

Natanz, not Naratz

From: "andrew cooke" <andrew@...>

Date: Tue, 30 Dec 2008 17:35:24 -0300 (CLST)

That should be Natanz.  Curiously, I'm not the only Google hit for Naratz
and Iranian nuclear installations - not sure if it's just chance or I
picked it up somehow -
http://www.eldeber.com.bo/2006/20060417/internacional_8.html

Andrew

Comment on this post