omniomni/omni-engineering huggingface dataset:
Moving equilibrium theorem. Consider a dynamical system

(1)..........

(2)..........

with the state variables  and . Assume that  is fast and  is slow. Assume that the system (1) gives, for any fixed , an asymptotically stable solution . Substituting this for  in (2) yields 

(3)..........

Here  has been replaced by  to indicate that the solution  to (3) differs from the solution for  obtainable from the system (1), (2).

The Moving Equilibrium Theorem suggested by  Lotka states that the solutions  obtainable from (3) approximate the solutions  obtainable from (1), (2) provided the partial system (1) is asymptotically stable in  for any given  and heavily damped (fast).

The theorem has been proved for linear systems comprising real vectors  and . It permits reducing high-dimensional dynamical problems to lower dimensions and underlies Alfred Marshall's temporary equilibrium method.

References

 https://epub.ub.uni-muenchen.de/39121/

Economics theorems
Experiment on Rapidly Intensifying Cyclones over the Atlantic. The Experiment on Rapidly Intensifying Cyclones over the Atlantic, or ERICA, is a scientific field project that started in the winter of 1988/1989. Its aims were to better understand the processes involved in rapid cyclogenesis, and so improve understanding and forecasting of the situations that cause it.

See also 
RAINEX

References

Meteorology research and field projects
SSI CEB. The Compact Electronics Bay Specification (CEB) as well as EEB, MEB and TEB ("Thin Electronics Bay") are standard form factors for dual or multi processor motherboards defined by the Server System Infrastructure (SSI) Forum. The specification is intended for value servers and workstations based on the Intel Xeon, and AMD Epyc processors (X399/C600 chipsets)

The SSI CEB specification was derived from the EEB and ATX specifications. SSI CEB motherboards have the same IO connector area and many of the same motherboard mounting holes as ATX motherboards, although SSI CEB motherboards are larger in size than ATX motherboards and have different processor mounting holes. The rear panel aperture is identical to the EEB and ATX specification and expansion cards mounted on an SSI CEB motherboard appear much the same as they would on an ATX motherboard.

To standardize thermal behavior, processor position is defined, including primary and secondary processor identification. For motherboards with only one processor installed, it is recommended the primary processor socket be populated first.

Gallery

External links
 ssiforum.org - Server System Infrastructure (SSI) Forum

Motherboard form factors
5086 aluminium alloy. 5086 aluminium alloy is an aluminium–magnesium alloy, primarily alloyed with magnesium. It is not strengthened by heat treatment, instead becoming stronger due to strain hardening, or cold mechanical working of the material.

Since heat treatment doesn't strongly affect the strength, 5086 can be readily welded and retain most of its mechanical strength. The good results with welding and good corrosion properties in seawater make 5086 extremely popular for vessel gangways, building boat and yacht hulls.

Basic properties
5086 has a density of , with a specific gravity of 2.66.

Melting point is .

Chemical properties
The alloy composition of 5086 is:
 Chromium - 0.05%–0.25% by weight
 Copper - 0.1% maximum
 Iron - 0.5% maximum
 Magnesium - 3.5%–4.5%
 Manganese - 0.2%–0.7%
 Silicon - 0.4% maximum
 Titanium - 0.15% maximum
 Zinc - 0.25% maximum
 Others each 0.05% maximum
 Others total 0.15% maximum
 Remainder Aluminium

Mechanical properties
The mechanical properties of 5086 vary significantly with hardening and temperature.

–O hardening
Unhardened 5086 has a yield strength of  and ultimate tensile strength of  from . At cryogenic temperatures it is slightly stronger: at , yield of  and ultimate tensile strength of ; above  its strength is reduced.

Elongation, the strain before material failure, ranges from 46% at , 35% at , 32% at , 22% at , 30% at , 36% at , and increases above there.

–H32 hardening
H32 strain hardened 5086, with properties measured at , has yield strength of , ultimate tensile strength of , and elongation of 6-12%.

–H34 hardening

–H112 hardening

–H116 hardening
H116 strain hardened 5086, with properties measured at , has yield strength of , ultimate tensile strength of , and elongation of 12%.

Uses
5086 is the preferred hull material for small aluminium boats or larger yachts. Its high strength and good corrosion resistance make it an excellent match for yachting.

5086 has a tendency to undergo Stress corrosion cracking and is not used much in aircraft construction as a result.

5086 has been used in vehicle armor, notably in the M113 Armored Personnel Carrier and M2 Bradley Infantry fighting vehicle.

Welding
5086 is often assembled using arc welding, typically MIG or TIG welding. The newer technique of Friction stir welding has also been successfully applied but is not in common use.

Arc welding reduces mechanical properties to no worse than –O hardening condition. For –H116 base material, measured at  ambient temperature, yield strength decreases from  to  and ultimate strength from . The relatively low decrease in ultimate strength (about 10%) is extremely good performance for an aluminium alloy.

References

Further reading
 "Properties of Wrought Aluminum and Aluminum Alloys: 5086, Alclad 5086", Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, Vol 2, ASM Handbook, ASM International, 1990, p. 93-4.

Aluminium alloy table 

Aluminium–magnesium alloys
USCGC Legare (WMEC-912). USCGC Legare (WMEC-912) is a United States Coast Guard medium endurance cutter. Legare was laid down July 11, 1986 at Robert Derecktor Shipyard Incorporated of Middletown, Rhode Island. She was named for Hugh Swinton Legare, a former United States Attorney General under President John Tyler. Legare was delivered December 1, 1989 and was commissioned August 4, 1990 at her homeport of Portsmouth, Virginia.

In 2009 the Legare participated in joint patrols with vessels of African nations.

The Legare arrived at the Coast Guard Yard on June 24, 2024 to begin a major overhaul. The work will be carried out under the  Service Life Extension Program and is collectively referred to as the "SLEP". It is intended to increase the cutter's lifetime by up to ten years by replacing her obsolete equipment and by generally making her easier to maintain. In particular, the Legares main diesel engines will be replaced. The other areas on which the SLEP will concentrate are the cutter's weapons system, electrical system and hull. The Legare is scheduled to spend 15 months in SLEP.

References

External links
 Legare home page

Ships of the United States Coast Guard
Famous-class cutters
Ships built in Middletown, Rhode Island
1989 ships
Cot filtration. C0t filtration, or CF, is a technique that uses the principles of DNA renaturation kinetics (i.e. Cot analysis) to separate the repetitive DNA sequences that dominate many eukaryotic genomes from "gene-rich" single/low-copy sequences. This allows DNA sequencing to concentrate on the parts of the genome that are most informative and interesting.

Concept
Briefly, when sheared genomic DNA in solution is heated to near boiling temperature, the molecular forces holding complementary base pairs together are disrupted, and the two strands of each double-helix dissociate or ‘denature.’  If the denatured DNA is then slowly returned to a cooler temperature, sequences will begin to ‘reassociate’ (renature) with complementary strands.  

The temperature at which renaturation occurs can be regulated so that little or no sequence mismatch is tolerated.  The rate at which a sequence finds a complementary strand with which to hybridize is directly related to how common that sequence is in the genome.  In other words, those sequences that are extremely abundant (on average) find complementary strands with which to pair relatively quickly while single-copy sequences take much longer to find complements.  

In CF, genomic DNA is heat-denatured and allowed to renature to a Cot value (Cot = DNA concentration x time x a factor based on the cation concentration of the buffer) at which the majority of repetitive elements have reassociated but single and low-copy elements remain single stranded.  Double-stranded, repetitive DNA is separated from single-stranded, low-copy DNA by hydroxyapatite chromatography or other means.

Application
CF allows the single/low copy sequences and the repetitive sequences of a genome to be studied independently of each other.  It can also be used to fractionate highly repetitive DNA from moderately repetitive sequences or to further fractionate isolated kinetic components.  CF is most accurately performed if fractionation is based upon the results of a Cot analysis.

See also 
C0t analysis

References

External links
Cot-Based Cloning and Sequencing Plant Genome Mapping Laboratory

Molecular biology
Laboratory techniques
CLHEP. CLHEP (short for A Class Library for High Energy Physics) is a C++ library that provides utility classes for general numerical programming, vector arithmetic, geometry, pseudorandom number generation, and linear algebra, specifically targeted for high energy physics simulation and analysis software.
The project is hosted by CERN and currently managed by a collaboration of researchers from CERN and other physics research laboratories and academic institutions.  According to the project's website, CLHEP is in maintenance mode (accepting bug fixes but no further development is expected).

CLHEP was proposed by Swedish physicist Leif Lönnblad in 1992 at a Conference on Computing in High-Energy Physics.  Lönnblad is still involved in maintaining CLHEP.
The project has more recently accepted contributions from other projects built on top of CLHEP, including the physics packages Geant4 and ZOOM, and the BaBar experiment at SLAC.

See also 
Geant4, a software using CLHEP
FreeHEP, a similar library to CLHEP
 COLT, a Java package for High Performance Scientific and Technical Computing, provided by CERN.

References

External links 
Project CLHEP website
CLHEP User Guide
CLHEP at CERN

Physics software
CERN software
Tinsel print. A  tinsel print  is a print where tinsel is added after printing, for decorative effect, it is made in two ways.

The first is a rare type of old master print parts of which are  decorated with small thin shiny fragments of metal or quartz crystal applied to glue. Gold leaf fragments were used on some, and colour was applied before the tinsel.  Arthur Mayger Hind cites fewer than ten examples as being "practically all whose location is known... all seem to date between about 1430 and 1460". All are religious woodcuts, and probably German in origin, perhaps from Augsburg.  They intended to imitate fabric, which was also the intention of the related "flock prints", printed in glue on paper that had been impressed on fabrics, and then sprinkled with chopped wool.

The second type are popular prints, mainly British, produced in the early or mid-19th century, normally showing actors in their roles, though Napoleon I in his study was another subject.  These were sold in plain or hand-coloured and tinselled versions, and the plain versions were often tinselled at home. Tin-foil tinsel in different colours, mostly in pre-stamped shapes, was applied with glue.  The theatrical prints cost one penny plain, and two coloured, with a standard size of about 12 by 10 inches (250 x 200 mm).  Actors, whether heroes or villains, were more often represented than actresses.  The artists are not named but the prolific political cartoonist and illustrator George Cruikshank is suspected of being involved.

Many prints also used fabric pieces and other additions (such as the plume of Mr Haines' helmet above).  Prints with fabric are called "dressed prints"; this seems to have begun in 18th-century France as a hobby, mainly on devotional images.  The same technique became popular for the smaller cut-out figures used in toy theatres, a craze of the period. A wide range of supplies for home-tinselling were available, or pre-tinselled figures could be bought.

Tinsel printing can also refer to Indian techniques for fabric.

Collections
Though popular in their day, theatrical tinsel prints were often not valued, and can deteriorate if not well looked after. They are now rare, especially in good condition.  There are collections in the Victoria and Albert Museum in London, the Cooper–Hewitt, Smithsonian Design Museum in New York, and the Folger Shakespeare Library was given a collection of 53 examples in 2003.

Notes

References

Areford, Davis S., The Viewer and the Printed Image in Late Medieval Europe, pp. 60–66 (using google books page refs), Routledge, 2017, , 9781351539678, google books 
"Grove": "Flock and tinsel prints", The Grove Encyclopedia of Materials and Techniques in Art, ed. Gerald W. R. Ward, 2008, Oxford University Press, , 9780195313918
Rickards, Maurice, The Encyclopedia of Ephemera: A Guide to the Fragmentary Documents of Everyday Life for the Collector, Curator, and Historian, 2000, Psychology Press, 2000, , 9780415926485, google books

Further reading
Roe, F.G, "Clowns and Tinsel: A Study in Motley", The Connoisseur, Volumes 113-114, 1944

Printmaking
Relief printing
MULTI2. MULTI2 is a block cipher, developed by Hitachi in 1988. Designed for general-purpose cryptography, its current use is encryption of high-definition television broadcasts in Japan.

Cipher details 
MULTI2 is a symmetric key algorithm with variable number of rounds. It has a block size of 64 bits, and a key size of 64 bits. A 256-bit implementation-dependent substitution box constant is used during key schedule. Scramble and descramble is done by repeating four basic functions (involutions).

History 
 1988 MULTI2 patent applied by Hitachi, Ltd on April 28
 1989 Algorithm announced to DPS-SIG Information Processing Society of Japan
 1991 Patent number 4982429 granted for MULTI2 algorithm in United States
 1994 Algorithm registered with ISO/IEC 9979 and assigned registration number 9
 1995 MULTI2 adopted as standard cipher for CS-Digital broadcasting in Japan
 1998 Japanese Patent number 2760799 granted for MULTI2 algorithm

Cryptanalysis 
There are a large class of equivalent keys in the Multi2 block cipher.  The largest class (so far found) stems from the fact that the Pi3 round function in the key schedule is not bijective.  For example, with the following 40-byte input key to the key schedule:

45 ec 86 d8 
b6 5e 24 d5 
38 fe 1d 90 
ce fc a4 22 
3e 39 1b e3 
da 03 0f cb 
9c 9e d7 c6 
1c e4 73 61 
d0 fa 39 86 
58 5d 5b 90 

You can perform the following single byte modifications (modification here means XOR against the original key byte):

Can mod byte 5 with CF
Can mod byte 7 with 77
Can mod byte 20 with 9A
Can mod byte 20 with A9
Can mod byte 20 with D7
Can mod byte 21 with 35
Can mod byte 21 with 6A
Can mod byte 21 with 9F
Can mod byte 21 with CC
Can mod byte 22 with 4D
Can mod byte 22 with 7A
Can mod byte 22 with A7
Can mod byte 23 with 53
Can mod byte 23 with AE

In this case there are 15 different keys which will schedule to the same 8 32-bit round keys for the ciphers bulk encryption path.  The keys are all different in the first keyword used in the Pi3 round function (keys k[1] and k[5]).  The collision occurs because a single byte difference turns into a pattern like 0X0X0000 (rotated by 0, 8, 16, or 24 bits) which then expands to a variation of 0X000X00 and finally in the second last line (with the rotate by 16 and the XOR) the differences cancel out.  Turning into a zero-delta.

The problem stems from the fact that the function 

x = ROL(x, y) ^ x

Where ROL means rotate left by y bits, is not bijective for any value of y.   There are similar problems with the Pi2 and Pi4 functions but they are seemingly harder to exploit because the rotation value is smaller.  

There are other observations too, for example

x = ROL(x, 1) - x

Found in Pi3, is an identity function for 50% of the values of x (where the most significant byte is zero).

This also means it is possible to have weak keys where instead of forcing single byte differences in the key, they are in the plaintext into Pi3 produces a zero-delta output and possibly leading to a 1R differential.

See also
 Integrated Services Digital Broadcasting

External links
 ALGORITHM REGISTER ENTRY, registered in 1994

Feistel ciphers
ISDB
Forster–Decker method. The Forster–Decker method is a series of chemical reactions that have the effect of mono-alkylating a primary amine (1), forming a secondary amine (6). The process occurs by way of transient formation of an imine (3) that undergoes the actual alkylation reaction.

Process stages
 Conversion of the primary amine to an imine (Schiff base) using an aldehyde.
 Alkylation of the imine using an alkyl halide, forming an iminium ion.
 Hydrolysis of the iminium, releasing the secondary amine and regenerating the aldehyde. 

Because the actual alkylation occurs on the imine, over-alkylation is not possible. Therefore, this method does not suffer from side-reactions such as formation of tertiary amines as a simple SN2-type process can.

See also
 Reductive amination

References

Substitution reactions
Name reactions
Information Harvesting. Information Harvesting (IH) was an early data mining product from the 1990s.  It was invented by Ralphe Wiggins and produced by the Ryan Corp, later Information Harvesting Inc., of Cambridge, Massachusetts. Wiggins had a background in genetic algorithms and fuzzy logic. IH sought to infer rules from sets of data.  It did this first by classifying various input variables into one of a number of bins, thereby putting some structure on the continuous variables in the input.  IH then proceeds to generate rules, trading off generalization against memorization, that will infer the value of the prediction variable, possibly creating many levels of rules in the process.  It included strategies for checking if overfitting took place and, if so, correcting for it.  Because of its strategies for correcting for overfitting by considering more data, and refining the rules based on that data, IH might also be considered to be a form of machine learning.

The advantage of IH, as compared with other data mining products of its time and even later, was that it provided a mechanism for finding multiple rules that would classify the data and determining, according to set criteria, the best rules to use.

References
 
Data mining and machine learning software
Sunbeam side-valve aircraft engines. Sunbeam, Wolverhampton, England, started to build aircraft engines in 1912. Louis Coatalen joined Sunbeam as chief engineer in 1909, having previously been Chief Engineer at the Humber company works in Coventry. The company quickly became one of the UK's leading engine manufacturers and even designed an aircraft of its own. Sunbeam discontinued the production of aircraft engines after Coatalen left the company in the 1930s.

Crusader engine 

In the autumn of 1912, Coatalen designed a V8 engine, which delivered 120 hp at 2500 rpm. It was called the Crusader and was announced in the British aviation press in March 1913. Aircraft manufacturers welcomed this, as no really suitable British engines were available at the time. The company procured a French Farman biplane in which to test the new engine, and also hired a full-time test pilot for the project. This was John Alcock, who later became well known for his famous non-stop Atlantic flight with Arthur Brown. The test flights began in the middle of October 1913, and took place at Brooklands. In December of that year, the aircraft began a long period of intensive flight tests, which ranged over most of southern England and continued until the outbreak of War in 1914.

Zulu engine 

The Zulu was developed during 1915. It was identical to the Crusader, except that the bore was increased from 90 mm to 100 mm and the reduction gear ratio was changed, allowing the engine to develop 160 hp at 2000 rpm. The Zulu engine was used in some Coastal Airships.

Mohawk engine 

Coatalen's next engine was an enlarged Crusader and was called the Mohawk. The Mohawk was a V12, side-valve engine, and (like the Crusader) was initially built with an 80 mm bore, which was soon increased to 90 mm. With its initial bore it developed 200 hp, when enlarged to 90 mm, it developed 225 hp and became known as the Sunbeam 225. Short seaplanes using this engine were often called "225s" because of this. The engine had two poppet side valves per cylinder, was water-cooled, weighed 905 lb dry, had four Claudel-Hobson carburettors, and two ignition magnetos.

Gurkha engine 

The Gurkha was developed as a replacement for the Mohawk and was of identical design, except that the bore was increased from  to  and the reduction gearing was reduced from 2:1 to 1.86:1. This allowed the engine to develop 240 hp at 2000 rpm. Production ended in October 1916, after 74 units had been supplied to power the Short Type 184 seaplanes of the Royal Naval Air Service.  The Gurkha engine preserved at the Fleet Air Arm Museum, Yeovilton, Somerset, England, is the only surviving Sunbeam side-valve engine in the world. It is installed in the Short 184, aircraft number 8359, that played a minor role in the Battle of Jutland at the end of May 1916. The pilot on that occasion was Flight Lieutenant Frederick Rutland (who was ever after known as "Rutland of Jutland"),

External links

References 

 

Sunbeam aircraft engines
1910s aircraft piston engines