omniomni/omni-engineering huggingface dataset:
Stellerite. Stellerite is a rare mineral discovered by and named after Georg Wilhelm Steller, a German explorer and zoologist. The mineral has a general formula of Ca[Al2Si7O18]·7H2O. Like most rare minerals, there are few commercial uses for stellerite. Mineral collectors are lucky to find it in good enough crystal form. Zeolites, including stellerite, have been studied using a dehydration process to gauge the potential use of their phases as molecular sieves, sorbents, and catalysts. Its occurrences are in cavities of andesite as sheaf-like clusters of small crystals.

Crystal habit 
Stellerite is part of the orthorhombic crystal system which means it has three axes of unequal length that intersect at 90° angles. Its crystal class is rhombic-dipyramidal which means it has three perpendicular two-fold rotational axes with perpendicular mirror planes. Stilbite, another zeolite, is very similar to stellerite in both chemical composition and physical appearance. Stellerite is more commonly found in rounded radiating clusters or as single crystals and appears more transparent than stilbite does.

Optical properties 
Stellerite is an anisotropic mineral, meaning that it has different properties in different directions-such as indices of refraction-when light passes through it. A refractive index (n) measures the speed of light in a substance—or in the case of mineralogy—in a mineral. It is expressed as a ratio of the speed of light in vacuum to that in a mineral. Stellerite has three indices of refraction because it is a biaxial mineral.

References

Aluminium minerals
Calcium minerals
Tectosilicates
Zeolites
Orthorhombic minerals
Minerals in space group 69
Fettelite. Fettelite, also known as sanguinite, is a mercury-sulfosalt mineral with the chemical formula Ag16HgAs4S15. The mineral was first described by Wang and Paniagua (1996) who named it after M. Fettel, a German field geologist who collected the first samples from Odenwald. It was first collected in the Nieder-Beerbach mine, 10 km south of Darmstadt, Odenwald, Germany. Its normal occurrence is in hydrothermal veins, which can cut gabbro-diorite intrusives. It is closely related to other rare minerals like dervillite, daomanite, vaughanite and criddleite which are also found in the same type locality as fettelite.

Fettelite occurs as clusters of hexagonal flakes. These flakes can get up to 0.2 mm across and around 5-10 μm thick. In more complex hexagonal tablets, somewhat larger sub parallel aggregates can be measured.  The birefringence of Fettelite is moderate white to grayish brown.

References

Arsenic minerals
Mercury(II) minerals
Silver minerals
Sulfosalt minerals
Monoclinic minerals
Minerals in space group 5
Minerals described in 1996
Ericssonite. Ericssonite has a general formula of BaMn2FeO[Si2O7](OH). It was discovered in 1967 and named after John Ericsson (July 31, 1803 – March 8, 1889), a well known Swedish American inventor, engineer and designer of the iron-clad ship USS Monitor. Ericssonite was discovered in the Jakobsberg Mine in Värmland, Sweden. 

Ericcsonite is monoclinic; this means it contains three unequal vectors, two of these vector angles are perpendicular while the other is at an angle greater than 90°. Optically  ericssonite is anisotropic which means that the mineral has more than one index of refraction, causing light to vary in speed depending on which axis it is traveling through. Since ericssonite is monoclinic, containing three unequal vectors, it has three indices of refraction. Ericssonite is usually a deep reddish-black in color. 

Ericssonite is only found in the Langban mine in Sweden, associated with a metamorphic manganese orebody. Also it is always inter-grown with orthoericssonite, which is almost identical to ericssonite except it contains extra silicon and oxygen in its chemical formula.

References

Barium minerals
Iron(III) minerals
Manganese(II) minerals
Sorosilicates
Monoclinic minerals
Minerals in space group 12
Minyulite. Minyulite is a rare phosphate mineral with a chemical formula of  (redefinition, IMA21-E).

It occurs as groups of radiating fine fibrous crystals within rock cracks of phosphatic ironstone. Minyulite belongs to the orthorhombic crystal system. This indicates that it has three axes of unequal length yet all are perpendicular to each other. Its cell constants are a=9.35, b=9.74 c=5.52. 

As for its optical properties, Minyulite is an anisotropic mineral which means the velocity of light differs when traveling through it depending on the cut of its cross-section which gives it more than one refractive index.  The mineral is optically biaxial. Its birefringence value is 0.007. It has three refractive indices which are nα=1.531 nβ=1.534 nγ=1.538.  Refractive indices are a ratio of the speed of light in a median with respect to the speed of light passing through the mineral.

Occurrence

It was first described in 1933 for an occurrence in Western Australia and named after the type locality, Minyulo Well in Western Australia.

Minyulite is considered as a secondary phosphate since it is formed by the alteration of a primary phosphate. It occurs in association with dufrenite, apatite, fluellite, wavellite, variscite and leucophosphite.

The mineral can be found in the underlying phosphatized rock zone of ornithogenic soil. Minyulite is not found in abundance, it can be found in the seashore of the maritime Arctic.

References

Phosphate minerals
Orthorhombic minerals
Minerals in space group 32
Potassium minerals
Aluminium minerals
Gananite. Gananite () is a rare bismuth fluoride mineral form of bismuth trifluoride with a general formula of BiF3. Gananite is an isotropic mineral, it belongs to the space group P43m. This means that gananite does not show any colors in cross polarized light, because when polarized light passes through it, it does not split into two perpendicular rays. In other words, because gananite is an isometric mineral, it does not exhibit double refraction. Moreover, this tells us that this mineral is not birefringent. Its color in plane-polarized light is blackish-brown, and it does not show pleochroism.

Discovery and occurrence 
It was first described in 1984 for an occurrence in the Laikeng Mining District, Gan County, Ganzhou Prefecture, Jiangxi Province, China. The name is given for its occurrence in the Southern Ganzhou (Gannan) region of China. In the Gannan occurrence, the only reported location, it occurs in quartz veins in association with wolframite, native bismuth, bismuthinite, pyrite and chalcopyrite.

Uses 
Despite the obscurity of gananite and its very limited use, it is sometimes used in China as a bismuth ore.

References 

Bismuth minerals
Cubic minerals
Minerals in space group 218
Fluorine minerals
Kanoite. Kanoite is a light pinkish brown silicate mineral that is found in metamorphic rocks. It is an inosilicate and has a chemical formula of .  It is a member of pyroxene group and clinopyroxene subgroup.

Crystallography
Kanoite crystallizes in the monoclinic crystal system. Its Hermann–Mauguin Symbol is 2/m. Under this crystal system, the three axes of the crystal are all different in length. The a and the b axes are perpendicular, and b and c axes are perpendicular. The a and c axes make an oblique shape. The axial ratio for kanoite is a:b:c =1.0894:1:0.5884 and the cell dimensions are: a = 9.73, b = 8.93 and c = 5.26 Å with Z = 4. Kanoite has a 2-fold axis and a mirror plane.

Kanoite is birefringent. It occurs as a mineral has 3 different indices of refraction. When the light passes through the Kanoite medium, the light splits due to unequal reflection from the crystal faces. As kanoite is birefringent, it is also anisotropic. In an anisotropic mineral, the velocity of light differs as the direction of the crystal changes.

Discovery and occurrence
Kanoite is a rare mineral which was found in Tatehira mine, Kumaishi, Oshima Peninsula, Hokkaido, Japan in 1977. In the type locality kanoite occurs along a joint that cuts a pyroxmangite-cummingtonite metamorphic rock in a  manganese ore deposit. The region has undergone contact metamorphism as magma intruded the area.  It was named to honor Hiroshi Kano, a petrology professor at Akita University in Japan.

It has also been reported from Broken Hill, New South Wales, Australia, the Semail Ophiolite in Oman, and the Balmat–Edwards zinc district, Saint Lawrence County, New York.

References

Gnos, E., Armbruster, T., and Nyfeler, D. (1996) Kanoite, donpeacorite and tirodite: Mn-Mg-silicates from a manganiferous quartzite in the United Arab Emirates. European Journal of Mineralogy, 8, 251-261.
Kobayashi, H. (1977) Kanoite, (Mn2+;Mg)2[Si2O6], a new clinopyroxene in the metamorphic rock from Tatehira, Oshima Peninsula, Hokkaido, Japan. The Journal of the Geological Society of Japan, 83, 537-542.
Arlt, T. and Armbruster, T. (1997) The temperature dependent P21/c-C2/c phase transition in the clinopyroxene kanoite MnMg[Si2O6]: a single-crystal X-ray and optical study. European Journal of Mineralogy, 9, 953–964.
Akimoto, S. and Syono, Y. (1972) High pressure transformations in MnSiO3. American Mineralogist, 57, 76–84.
Mineral Data Publishing, 2001, “Kanoite.” http://rruff.geo.arizona.edu/doclib/hom/kanoite.pdf. Accessed 21 October 2010.
Ralph, Jolyon and Chau, Ida, 5 November 2010, “Kanoite.” http://www.mindat.org/min-2154.html. Accessed 1 November 2010.
Barthelmy, David, 1997-2010, “Kanoite Mineral Data.” http://www.webmineral.com/data/Kanoite.shtml. Accessed 7 November 2010.
Weisstein, Eric, 1996-2007, “Birefringence.” http://scienceworld.wolfram.com/physics/Birefringence.html. Accessed 7 November 2010.

Inosilicates
Magnesium minerals
Manganese(II) minerals
Monoclinic minerals
Minerals in space group 14
Pyroxene group
Dyscrasite. The silver antimonide mineral dyscrasite has the chemical formula Ag3Sb.  It is an opaque, silver white, metallic mineral which crystallizes in the orthorhombic crystal system. It forms pyramidal crystals up to  and can also form cylindrical and prismatic crystals.

Crystallography and properties
Dyscrasite is a metal ore and is opaque. In reflected light, however, it demonstrates weak anisotropism. Dyscrasite’s color under plane polarized light is most likely dark grey/black. When spun on a rotatable stage of a microscope (under plane polarized light), dyscrasite’s color should slightly change shades. This property is called pleochroism. Dyscrasite exhibits very weak reflected light pleochroism.

Dyscrasite belongs to the orthorhombic crystal class, meaning all three of its axes (a, b, and c) are unequal in length and are 90° to each other.

Discovery and occurrence
It was first described for an occurrence in 1797 in the Wenzel Mine, Black Forest, Germany. The name dyscrasite comes from the Greek word δυσκράσις, meaning "a bad alloy."

It occurs as a hydrothermal mineral in silver bearing veins in association with native silver, pyrargyrite, acanthite, stromeyerite, tetrahedrite, allemontite, galena, calcite and baryte.

See also

 Classification of minerals
 List of minerals

References 

Antimonide minerals
Silver minerals
Orthorhombic minerals
Minerals in space group 25
Sweetite. Sweetite has a general formula of Zn(OH)2. The name is given after a curator of mineral department of the British Museum, Jessie May Sweet (1901–1979). It occurs in an oxidized vein in limestone bedrock with galena, ashoverite, wülfingite, anglesite, cerussite, hydrocerussite, litharge, fluorite, palygorskite and calcite.

Sweetite is tetragonal, which means crystallographically it contains one axis of unequal length and two axes of equal length. The angles between three of the axes are all 90°. It belongs to the space group 4/m. Some crystals show evidence of a basal plane and a few are tabular. In terms of its optical properties, sweetite has two indices of refraction, 1.635 along the ordinary ray and 1.628 along the extraordinary ray. The index of refraction is the velocity of light in vacuum divided by the velocity of light in medium. It also has the birefringence of 0.007. The birefringence means the decomposition of light into two rays when passing through a mineral. Sweetite is 1.64–1.65 in relief, which is medium to high in intensity and means a measure of the relative difference between the index of refraction of a mineral and its surrounding medium. 

Sweetite is mostly found from a limestone quarry 200–300 m northwest of Milltown, near Ashover, Derbyshire, England.

References 

Hydroxide minerals
Zinc minerals
Tetragonal minerals
Minerals in space group 92
Minerals in space group 96
Minerals described in 1983
Pinalite. Pinalite is a rare lead tungstate–chloride mineral with formula: Pb3WO5Cl2.  

Pinalite crystallizes in the orthorhombic crystal system. The orthorhombic system is described as having three crystallographic axes of unequal lengths, normally referred to as c (the longest axis), b (the second longest axis), and a (the smallest axis). These axes all have corresponding angles of 90 degrees. Pinalite belongs to the biaxial optical class, and is negative. The main difference between biaxial and axial crystals is that biaxial crystals have two optic axes.

Pinalite's structure is significant in that it is one of a kind. It is therefore important in seeing how the structures in new lead oxyhalides (containing square pyramids incorporated into sheets) are arranged. Its structure contains an extra oxygen, which therefore has a very small amount of free space and consequently protrudes into neighboring layers. The oxygen then pushes aside the chlorine atoms, leaving almost no room for the lead to occupy. This is of interest to geologists for it is such a rare occurrence of structure seen only in pinalite and its barium analog. Therefore, it could be of use to structuralists to see how this mineral was formed. Experiments have been done, using lead oxyhalides, to see the reason and sequence of events in which this mineral is executed.

Discovery and occurrence
Pinalite was first discovered in 1989 in the St. Anthony deposit, Tiger, Mammoth District, Pinal Co., Arizona, US, and was named for the location county. Pinalite has otherwise only been seen in the Grand Reef mine, near Klondyke in the Santa Teresa Mountains in Graham County, Arizona, so is therefore found around orogenic activity.

References 

Lead minerals
Tungstate minerals
Chloride minerals
Orthorhombic minerals
Minerals in space group 63
Vertical seat. The vertical seat (standing seat, stand-up seat) is an airline seat configuration, created in 2003 by Airbus, canvassed to Asian carriers in 2006, and promoted by Ryanair as well as Spirit Airlines in 2010. The configuration involves standing passengers travelling while being braced in position.

The configuration and all designs have not yet been approved by regulatory agencies. There is no bar to such a configuration in Federal Aviation Administration (US) regulations. However, according to Transport Canada (the agency responsible for aviation safety in Canada), vertical seats do not conform to Canadian seating requirements.

In 2006, Airbus was quietly polling airlines to see about the viability of a perch seat, which it had created in 2003.

In 2010, Ryanair promulgated a vertical seat design for use in its aircraft. Both the European Aviation Safety Agency and UK Civil Aviation Authority were skeptical as to the design being able to meet licensing requirements. The design was expected to start undergoing safety trials in the 2011–2012 time frame. It has already been rejected by Boeing, as it believes that the design would not meet the 16G regulatory requirement. Tigerair Australia announced that it would also pursue the Ryanair design, as has its parent, Tigerair. According to UK aviation law, passengers require a seat belt on landing and takeoff, so the lack of a seat may preclude the design from being legal in the UK. The Ryanair design would have passengers perched on a narrow shelf, with their weight taken up by their legs, and their back against the seatback, strapped in, with additional shoulder restraints similar to roller coaster overhead restraints.

The configuration is superficially similar to the SkyRider saddle seat design proposed by Aviointeriors.

In 2015, Chinese airline Spring Airlines expressed interest in using the vertical seat concept for consumer flights. In 2018, the Italian company Aviointeriors revealed its design for vertical seats.

References 

Aircraft cabin components
Airliner seating
Beta encoder. A beta encoder is an analog-to-digital conversion (A/D) system in which a real number in the unit interval is represented by a finite representation of a sequence in base beta, with beta being a real number between 1 and 2. Beta encoders are an alternative to traditional approaches to pulse-code modulation.

As a form of non-integer representation, beta encoding contrasts with traditional approaches to binary quantization, in which each value is mapped to the first N bits of its base-2 expansion. Rather than using base 2, beta encoders use base beta as a beta-expansion.

In practice, beta encoders have attempted to exploit the redundancy provided by the non-uniqueness of the expansion in base beta to produce more robust results. An early beta encoder, the Golden ratio encoder used the golden ratio base for its value of beta, but was susceptible to hardware errors. Although integrator leaks in hardware elements make some beta encoders imprecise, specific algorithms can be used to provide exponentially accurate approximations for the value of beta, despite the imprecise results provided by some circuit components.

An alternative design called the negative beta encoder (called so due to the negative eigenvalue of the transition probability matrix) has been proposed to further reduce the quantization error.

See also
 Pulse-code modulation
 Quantization (signal processing)
 Sampling (signal processing)

References

Digital signal processing
Signal processing
Wag-Aero CUBy. The Wag-Aero CUBy is a replica of the Piper J-3, designed by Dick Wagner and marketed by Wag-Aero of Lyons, Wisconsin as plans or in kit form.

The aircraft is currently marketed under the name Wag-Aero Sport Trainer.

Design and development
Wag-Aero  started with a line of inspection covers, then eventually a comprehensive line of aircraft parts, including a full line of parts for the Piper Cub. After several attempts to purchase the rights to the Piper Cub for new production, Wag-Aero owner Jack Wagner designed a homebuilt kit that would allow homebuilders to construct new aircraft similar to the Cub.

While the CUBy was initially offered with wooden wing ribs and spars like the Piper Cub, aluminum ribs and spars were later added as an option, also like later Cubs. The aircraft does differ from the original Piper design in several ways including having its fuselage fabricated from 4130 steel instead of the Cub's original 1025 carbon steel and utilizing a conventional elevator-mounted trim tab in place of the Cub's jack screw trimming system that adjusts the Cub's elevator angle of incidence.

The CUBy drawings were drafted by Bill Blake.

The prototype first flew on March 12, 1975 fitted with skis.

Operational history
The introductory model was displayed with a contrasting paint scheme, one half painted green with a yellow stripe, and the other half painted yellow with a green stripe. This unusual "court jester" paint scheme was used to differentiate the prototype from the standard yellow scheme used on the Piper Cub, for marketing purposes.
Paul Poberezny became the first customer to build a CUBy. Poberezny's aircraft became part of the EAA AirVenture Museum Foundation and was used to demonstrate the use of automotive fuel in aircraft engines for the Experimental Aircraft Association. The designer of the aircraft Dick Wagner flew the unpressurized aircraft as high as  to demonstrate that auto fuel would not cause vapor lock.

Variants

CUBy
Base model, powered by a recommended standard Continental C-85 engine of  
CUBy Acro Trainer
Developed in 1977, the aircraft was fitted with a  Lycoming and clipped wings. The prototype featured the unique split-down the middle paint scheme  employed by Wag-Aero.
Observer
Sport Trainer with modifications to alter the window installation to resemble the Piper L-4
Sport Trainer
 Original CUBy renamed, powered by engines in the recommended range of . By December 2011 250 examples had been completed and flown.
Super Sport
Sport trainer with modifications to accept engines of up to

Specifications (Wag-Aero CUBy)

See also

References

External links

Wag-Aero aircraft
Homebuilt aircraft
High-wing aircraft
Single-engined tractor aircraft
Aircraft first flown in 1975
Aircraft with fixed conventional landing gear
Studenitsite. Studenitsite is a rare borate mineral with chemical formula of .

Studenitsite has a vitreous luster, a Mohs hardness of 6 and color of light-dirty yellow. It is a monoclinic mineral and belongs to the space group P2/c. The basic unit of the crystal structure  layers has a Miller index of (001).  Studenitsite has a low surface relief, which means the measure of the relative difference between the index of refraction of the mineral and surrounding medium is small. Birefringence is the difference between two principal indices of refraction of a uniaxial crystal. Studenitsite has a maximum birefringent value of . Studenitsite has three indices of refraction. Their values are , , . Indices of refraction are the ratio of the light's speed in the mineral and the medium.

Studenitsite is an extremely rare mineral that has only been found in the Piskaya deposit, Yarondolskii Basin, on the Ibar River,  south of Belgrade, Serbia.  The deposit is classified as a volcanogenic-sedimentary borate deposit with clay and carbonate minerals.  It occurs associated with colemanite, howlite, ulexite and pentahydroborite.  It is a rare but important mineral for understanding the volcanic settings in Western Serbia.  It was named after the Studenica cloister near the discovery location.

See also

 List of minerals

References

Calcium minerals
Sodium minerals
Phylloborates
Monoclinic minerals
Minerals in space group 14
Instituto de Plasmas e Fusão Nuclear. Instituto de Plasmas e Fusão Nuclear (IPFN) (Institute for Plasmas and Nuclear Fusion) is a research unit of Instituto Superior Técnico (IST), Lisbon, and a leading Portuguese institution in physics research. IPFN has the status of Associate Laboratory in the thematic areas of controlled nuclear fusion, plasma technologies and intense lasers, granted by the Portuguese Foundation for Science and Technology.

IPFN was formally created in January 2008, as a result of the merging between the former research units Center for Nuclear Fusion and Center for Plasma Physics. As of 2015, almost 190 people work at IPFN, of which more than 100 are PhDs.

Organization
IPFN is organized in seven research groups: Engineering and Systems Integration, Experimental Physics, Materials Processing and Characterisation, Theory and Modelling, Lasers and Plasmas, Gas Discharges and Gaseous Electronics, and High Pressure Plasmas. The activities in the frame of the Associate Laboratory are evaluated by an External Evaluation Committee. IPFN is also the research unit of the Contract of Association between EURATOM and IST, in force since 1990. These activities are coordinated by the Head of Research Unit and monitored by a steering committee.

Main research fields
IPFN activities are centered on the following competences:

 Magnetic Confinement Fusion Devices
 Fusion Engineering Systems
 Fusion Theory and Modelling
 Inertial fusion
 Laser-Plasma Accelerators
 High-Performance Computing
 Relativistic Astrophysics
 Novel Radiation Sources
 Ultra Intense Photonics
 Space Physics
 Environmental Plasma Engineering Laboratory
 Kinetics in Plasmas and Afterglows
 Modelling of Plasma Sources
 Quantum Plasmas

See also
 Instituto Superior Técnico

References

External links
 Instituto de Plasmas e Fusão Nuclear (official page)

Research institutes in Portugal
Fusion power
Plasma physics facilities
Physics research institutes
Tokamaks
University of Lisbon