Category: Uncategorized

Can a waterjet be made from a centrifuge?

A waterjet is fast moving water:
waterjet water speed at 40,000 psi = 680 m/s
waterjet water speed at 60,000 psi = 1021 m/s

A pressure washer gives water a speed of 110 m/s.

How fast can a centrifuge spin? Ultracentrifuge speed:
centrifuge spins at 1e5 rpm, has a 10 cm radius rotor.
This give a speed at the rim of:
45 cm rotor circumference at the bottom of the tube
1e5/60 rotations / sec
0.45m/60 x 1e5 = 7.5e2 m/s
So a centrifuge does get water moving fast enough to act as a waterjet.

To turn the rotor spin into a line of water drops, open a door in the bottom of the rotor as the rotor passes a certain point in every spin (1000-2000 times / sec).

If the door is open for 10 us, the rotor will spin 1.5mm.
If the door is open for 1 us, the rotor will spin 0.15 mm.
The water stream will come out in a line, so the resolution in the other dimension can be finer, with the waterjet spread out along the direction of the cut.

A door can’t be mechanically opened and closed that fast, 1 ms is likely the limit.

But a reasonable solution is a rotating (or vibrating) plate with a hole, say spinning 1000/s (or 100/s, opening only every tenth pass), and synchronized with the main rotor spin so opening appeared at the same point along the edge. This would tend to torque the main rotor, but it might be tolerable.

This would give a waterjet with slower cutting–the drop density is 1:1000 or 1:10,000 of a stream.

The rotor would need to be refilled and have enough power to accelerate the new water, and solidly built enough to overcome vibration/torque. And fast centrifuges are expensive.

A micofuge will only give a water speed of 125 m/s.

Thermo Nicolet IR200 Spectrometer

Thermo Nicolet IR200 Spectrometer investigation

Requires a custom power brick, multiple pins. Could not find power specifications. Power bricks do not seem to be available.

Laser was removed from this unit. This is a HeNe laser used “provies the reference signal for triggering data collections and measuring the stroke of the moving mirror.”

Dessicant spot indicates that the dessicant was exhausted. Dessicant appears to be a standard pack. Recharged dessicant in 250F oven for three hours. I’ll try to preserve the optics, I may be able to reuse them.

Requires ENCOMPASS or OMNIC software. I was able to find an OMNIC iso. Untested.

“The interferometer window in your spectrometer is made of KRS-5…” KRS-5 is thallium bromoiodide (TlBr-TlI). KRs-5 (TlBr-TlI) is a gorgeous red crystal commonly used for attenuated total reflection prisms for IR spectroscopy. It is also used as an infrared transmission window in gas and liquid sample cells used with FTIR spectrophotometers in place of Potassium Bromide (KBr) or Cesium Iodide (CsI) for analysis of aqueous samples that would attack KBr or CsI optics. It has a wide transmission range and is virtually insoluble in water. It is a useful alternative to AgCl since it is not photo-sensitive and for ATR applications it will transmit well beyond the 18 micron useful range of ZnSe.

Background on FT-IR:
Nicolet brochure

Unit with case removed:

IR mirror on the left. The right side module looks like a detector:

Back of detector module:

Dry optics compartment:

Dry optics compartment:

Laser diode?:

Corner mirror and flat mirror:

Second corner mirror on solenoid:

Nicolet IR100 and Nicolet IR200 User’s Guide
Nicolet 4700 or Nicolet 6700 User’s Guide
OMNIC User’s Guide, v7.4Transport Kit User’s Guide
Also have “OMNIC- for TIR.iso”
Could not find a service manual.

Beckman DB-G Grating Spectrophotometer teardown

Beckman DB-G Grating Spectrophotometer, Cat NO. 1403.

Links: Grating Spectrophotometer DB GT (1961), University of Queensland Physics Museum

E 871 (3 leads, HID, for UV)
GE 2331 (visible, 5.9V, 4.66A, 25W)

photomultiplier RCA IP28A, 69-04 (Anode supply: 1250V. Voltage between dynode No9 and anode: 250V. D-C anode current: 2.5ma. Ambient temperature: 75 Deg C. Package: 1-5/16″ D x overall length 3-11/16″ long. Seated height 3-1/8″ long. base: 11 pin plug-in with socket and 30″ cable. Note: Specification sheet available. Maybe replaced with 931A, average anode characteristics are the same.)

Photomultiplier board:
Vacuum tubes:

Main board:
Adams and Westlake Mercury Wetted Contact Relay – MWSL-15093-1B
Vacuum tubes (all filaments lighted):

2014 Hugos


These look interesting:

Best Novel (1595 nominating ballots)
Ancillary Justice, Ann Leckie (Orbit US/Orbit UK)
Neptune’s Brood, Charles Stross (Ace / Orbit UK)
Parasite, Mira Grant (Orbit US/Orbit UK)

Best Short Story (865 nominating ballots)
“If You Were a Dinosaur, My Love”, Rachel Swirsky (Apex Magazine, Mar-2013)
“The Ink Readers of Doi Saket”, Thomas Olde Heuvelt (, 04-2013)
“Selkie Stories Are for Losers”, Sofia Samatar (Strange Horizons, Jan-2013)
“The Water That Falls on You from Nowhere”, John Chu (, 02-2013)

Best Related Work (752 nominating ballots)
“We Have Always Fought: Challenging the Women, Cattle and Slaves Narrative”, Kameron Hurley (A Dribble of Ink)

The John W. Campbell Award for Best New Writer
Wesley Chu
Max Gladstone*
Ramez Naam*
Sofia Samatar*
Benjanun Sriduangkaew


Idea: make a microcentrifuge using RC motors

The motors made for RC planes and cars are high speed and high power.

For example, the Turnigy Trackstar 1/10 12.0T 3300KV Brushless Motor, $23 specs are:
Kv: 3300
Max Voltage: 15v
Max current: 35amps
Watts: 550
Resistance: 0.0221Ohms
Max RPM: 50000

The load on a microfuge will be greater–22 tubes x 1.5 ml can be roughly 44g, figure a 100g total load with the rotor. So slower than max, but still quite fast.

High power ESC modules are sold to run these motors. So they take DC power, and a servo like signal (PWM), +5, GRD.

So a 10k RPM microfuge can be made with one of these motors + ESC, a servo for locking the lid, and a microcontroller to run it, take speed / time settings, and monitor and show the RPMs on a display.

Power could be from a PC power supply or a dedicated supply.

Setting up libcutter

On Ubuntu 12.04.

Downloaded from

It was hard to compile, requiring libsvg and several other libraries.
I added to the include directories:


include_directories(${PROJECT_SOURCE_DIR}/include/ ${PROJECT_SOURCE_DIR}/include/pub /usr/include/freetype2)

Download keys.h from:

#ifndef KEYS_H
#define KEYS_H
#define MOVE_KEY_0 1194338851ul
#define MOVE_KEY_1 1563510831ul
#define MOVE_KEY_2 992311905ul
#define MOVE_KEY_3 913389615ul

#define LINE_KEY_0 809461859ul
#define LINE_KEY_1 1902406960ul
#define LINE_KEY_2 1198081403ul
#define LINE_KEY_3 1832133993ul

#define CURVE_KEY_0 0x7D316E22ul
#define CURVE_KEY_1 0x4A4A7133ul
#define CURVE_KEY_2 0x5A3C5C5Ful
#define CURVE_KEY_3 0x78613A61ul

Full set of keys:

KEY0 - 0x272D6C37, 0x342A6173, 0x3663255B, 0x2B265A4D
KEY1 - 0x7D316E22, 0x4A4A7133, 0x5A3C5C5F, 0x78613A61
KEY2 - 0x47302A23, 0x5D31482F, 0x3B257A61, 0x3671382F
KEY3 - 0x303F6863, 0x71646D30, 0x4769457B, 0x6D342569
KEY4 - 0x45356650, 0x3A386D69, 0x575A7037, 0x335F357D
KEY5 - 0x343A2148, 0x614F3925, 0x753F6953, 0x47463626
KEY6 - 0x3F62626D, 0x7E555F44, 0x7E29425A, 0x52246268
KEY7 - 0x47302A23, 0x342A6173, 0x4769457B, 0x335F357D

Replaces include/pub/keys.h

./util/draw_svg ./util/svg_tests/Mini_DIY_circuit.svg /dev/ttyUSB0

Test run, worked!

Other options:
Freecut — Firmware replacement, haven’t tried.
Licut –Tried binaries and program compiled from source, did not work.

Cricut dissection, discusses the default blank cartridge.
ATX Hackerspace cricut page
Repair info
Build-to-spec Cricut Hacks Wiki (recovered from the Internet Archive)

Dinosaur coloration

In the last decade or so, dinosaurs have started being depicted as brightly colored. The reason for the trend of brightly colored dinosaurs in movies is that in recent years techniques for identifying pigments from fossils have been developed, using electron microscopy and ion bombardment mass spectrometry.

News report: Ancient Pigments Unearthed: Fossilized skin reveals the colors of three extinct marine reptiles by Ed Yong. The Scientist, January 8, 2014
Original article: (Abstract) Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles. Lindgren et. al., Nature 08 Jan 2014

and news report: Pictures: Dinosaur True Colors Revealed by Feather Find, Chris Sloan, National Geographic Daily News
Original article: Zhang et. al., 2010

Fossil color studies were pioneered by Jakob Vinther at Yale

No doubt movie speculation is running far ahead of the science, but these are the discoveries that unleashed the trend of brightly colored dinosaurs. At this point, it is reasonable to think dinosaurs are as brightly colored as birds or reptiles are today, and in some cases the coloring of specific species is known.

Ideas: sensors

Further notes on using digital camera sensors as high density multimodal sensor arrays.

1) Detect loading / strain using a module incorporating a strain sensor (e.g. the resistive type used in scales and strain gauges) to a diode. The diode is coupled to a fiber optic line that takes the signal to the camera.spectrometer.

2) Position sensors. Use an arc of partially clear plastic that has a light at one of the ends at the arc edge. A fiber optic line at the oriented normal to the arc gathers light that takes the signal to the camera. As the joint moves, the plastic arc moves and distance between the light and the fiber optic changes. This change is converted to a position.

For joints with 360 rotation, the arc of plastic is replaced by a disk. The light source is placed at the center, and an opaque radial line gives each position of the disk a different light intensity.

3) Touch sensors. Use my previous idea of an array of sensors embedded in a squishy and translucent layer with one or more light sources. Touch distorts the light path of direct or reflected light between the light source(s) and sensor in reproducible ways. The set of sensors is trained to recognize the pattern of light formed by different touches. The pattern may also be changed by movement of the surface, for example if the array of sensors covers a hand, and could bed used to detect hand position.

4) An array of fibers can be placed to collect light from a spectrometer. An array of spectrometers can be developed using this approach, as the camera can collect light from several 1D fiber optic arrays.