Software inspection

Inspection in software engineering, refers to peer review of any work product by trained individuals who look for defects using a well defined process. An inspection might also be referred to as a Fagan inspection after Michael Fagan, the creator of a very popular software inspection process.
Introduction.
An inspection is one of the most common sorts of review practices found in software projects. The goal of the inspection is to identify defects. Commonly inspected work products include software requirements specifications and test plans. In an inspection, a work product is selected for review and a team is gathered for an inspection meeting to review the work product. A moderator is chosen to moderate the meeting. Each inspector prepares for the meeting by reading the work product and noting each defect. In an inspection, a defect is any part of the work product that will keep an inspector from approving it. For example, if the team is inspecting a software requirements specification, each defect will be text in the document which an inspector disagrees with.
Inspection process.
The inspection process was developed in the mid-1970s and it has later been extended and modified.
The process should have entry criteria that determine if the inspection process is ready to begin. This prevents unfinished work products from entering the inspection process. The entry criteria might be a checklist including items such as "The document has been spell-checked".
The stages in the inspections process are: Planning, Overview meeting, Preparation, Inspection meeting, Rework and Follow-up. The Preparation, Inspection meeting and Rework stages might be iterated.
The process is ended by the moderator when it satisfies some predefined exit criteria.
The term inspection refers to one of the most important elements of the entire process that surrounds the execution and successful completion of a software engineering project.
Inspection roles.
During an inspection the following roles are used.
Related inspection types.
Code review.
A code review can be done as a special kind of inspection in which the team examines a sample of code and fixes any defects in it. In a code review, a defect is a block of code which does not properly implement its requirements, which does not function as the programmer intended, or which is not incorrect but could be improved (for example, it could be made more readable or its performance could be improved). In addition to helping teams find and fix bugs, code reviews are useful both for cross-training programmers on the code being reviewed and for helping junior developers learn new programming techniques.
Peer reviews.
Peer reviews are considered an industry best-practice for detecting software defects early and learning about software artifacts. Peer Reviews are composed of software walkthroughs and software inspections and are integral to software product engineering activities. A collection of coordinated knowledge, skills, and behaviors facilitates the best possible practice of Peer Reviews. The elements of Peer Reviews include the structured review process, standard of excellence product checklists, defined roles of participants, and the forms and reports.
Software inspections are the most rigorous form of Peer Reviews and fully utilize these elements in detecting defects. Software walkthroughs draw selectively upon the elements in assisting the producer to obtain the deepest understanding of an artifact and reaching a consensus among participants. Measured results reveal that Peer Reviews produce an attractive return on investment obtained through accelerated learning and early defect detection. For best results, Peer Reviews are rolled out within an organization through a defined program of preparing a policy and procedure, training practitioners and managers, defining measurements and populating a database structure, and sustaining the roll out infrastructure.


Sun-synchronous orbit

A sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is an orbit arranged so that it precesses through one complete revolution each year, so it always maintains the same relationship with the Sun. A Sun-synchronous orbit is useful for imaging, spy, and weather satellites, because every time that the satellite is overhead, the surface illumination angle on the planet underneath it will be nearly the same.
Applications.
A Sun-synchronous orbit is useful for imaging, spy, and weather satellites, because every time that the satellite is overhead, the surface illumination angle on the planet underneath it will be nearly the same. This consistent lighting is a useful characteristic for satellites that image the Earth's surface in visible or infrared wavelengths, such as weather and spy satellites; and for other remote-sensing satellites, such as those carrying ocean and atmospheric remote-sensing instruments that require sunlight. For example, a satellite in Sun-synchronous orbit might ascend across the equator twelve times a day each time at approximately 15:00 mean local time.
Special cases of the Sun-synchronous orbit are the noon/midnight orbit, where the local mean solar time of passage for equatorial latitudes is around noon or midnight, and the dawn/dusk orbit, where the local mean solar time of passage for equatorial latitudes is around sunrise or sunset, so that the satellite rides the terminator between day and night. Riding the terminator is useful for active radar satellites, as the satellites' solar panels can always see the Sun, without being shadowed by the Earth. It is also useful for some satellites with passive instruments that need to limit the Sun's influence on the measurements, as it is possible to always point the instruments towards the night side of the Earth. The dawn/dusk orbit has been used for solar-observing scientific satellites such as Yohkoh, TRACE, Hinode and PROBA2, affording them a nearly continuous view of the Sun.
Orbital precession.
A Sun-synchronous orbit is achieved by having the osculating orbital plane precess (rotate) approximately one degree eastward each day with respect to the celestial sphere to keep pace with the Earth's movement around the Sun. This precession is achieved by tuning the inclination to the altitude of the orbit (see Technical details) such that Earth's equatorial bulge, which perturbs inclined orbits, causes the orbital plane of the spacecraft to precess with the desired rate. The plane of the orbit is not fixed in space relative to the distant stars, but rotates slowly about the Earth's axis.
Typical Sun-synchronous orbits around Earth are about 600–800 km in altitude, with periods in the 96–100-minute range, and inclinations of around 98°. This is slightly retrograde compared to the direction of Earth's rotation: 0° represents an equatorial orbit, and 90° represents a polar orbit.
Sun-synchronous orbits are possible around other oblate planets, such as Mars. A satellite orbiting a planet such as Venus that is almost spherical will need an outside push to maintain a Sun-synchronous orbit.
Technical details.
The angular precession per orbit for an Earth orbiting satellite is given by
where
An orbit will be Sun-synchronous when the precession rate equals the mean motion of the Earth about the Sun, which is 360° per sidereal year (), so we must set , where is the orbital period.
As the orbital period of a spacecraft is
where is the semi-major axis of the orbit and is the standard gravitational parameter of the planet ( for Earth); as for a circular or almost circular orbit, it follows that
or when is 360° per year,
As an example, for = (the spacecraft about 800 km over the Earth surface) one gets with this formula a Sun-synchronous inclination of 98.696°.
Note that according to this approximation equals −1 when the semi-major axis equals , which means that only smaller orbits can be Sun-synchronous. The period can be in the range from 88 minutes for a very low orbit ( = , = 96°) to 3.8 hours ( = , but this orbit would be equatorial with = 180°). A period longer than 3.8 hours may be possible by using an eccentric orbit with < but > .
If one wants a satellite to fly over some given spot on Earth every day at the same hour, it can do between 7 and 16 orbits per day, as shown in the following table. (The table has been calculated assuming the periods given. The orbital period that should be used is actually slightly longer. For instance, a retrograde equatorial orbit that passes over the same spot after 24 hours has a true period about ≈ 1.0027 times longer than the time between overpasses. For non-equatorial orbits the factor is closer to 1.)
When one says that a Sun-synchronous orbit goes over a spot on the Earth at the same "local time" each time, this refers to mean solar time, not to apparent solar time. The Sun will not be in exactly the same position in the sky during the course of the year (see Equation of time and Analemma).
Sun-synchronous orbits are mostly selected for Earth observation satellites, with an altitude typically between 600 and over the Earth surface. Even if an orbit remains Sun-synchronous, however, other orbital parameters such as argument of periapsis and the orbital eccentricity will evolve, due to higher order perturbations in the Earth's gravitational field, the pressure of sunlight, and other causes. Earth observation satellites, in particular, prefer orbits with constant altitude when passing over the same spot. Careful selection of eccentricity and location of perigee reveals specific combinations where the perturbations largely cancel and hence the orbit is relatively stable – a frozen orbit. The ERS-1, ERS-2 and Envisat of European Space Agency, as well as the MetOp spacecraft of EUMETSAT and RADARSAT-2 of the Canadian Space Agency, are all operated in such Sun-synchronous frozen orbits.


2378 Pannekoek


Chromatic diesis


Imaging spectroscopy

In imaging spectroscopy (also hyperspectral imaging or spectral imaging) each pixel of an image acquires many bands of light intensity data from the spectrum, instead of just the three bands of the RGB color model. More precisely, it is the simultaneous acquisition of spatially coregistered images in many spectrally contiguous bands.
Some spectral images contain only a few image planes of a spectral data cube, while others are better thought of as full spectra at every location in the image. For example, solar physicists use the spectroheliograph to make images of the Sun built up by scanning the slit of a spectrograph, to study the behavior of surface features on the Sun; such a spectroheliogram may have a spectral resolution of over 100,000 (formula_1) and be used to measure local motion (via the Doppler shift) and even the magnetic field (via the Zeeman splitting or Hanle effect) at each location in the image plane. The multispectral images collected by the Opportunity rover, in contrast, have only four wavelength bands and hence are only a little more than 3-color images.
To be scientifically useful, such measurement should be done using an internationally recognized system of units.
One application is spectral geophysical imaging, which allows quantitative and qualitative characterization of the surface and of the atmosphere, using radiometric measurements. These measurements can then be used for unambiguous direct and indirect identification of surface materials and atmospheric trace gases, the measurement of their relative concentrations, subsequently the assignment of the proportional contribution of mixed pixel signals (e.g., the spectral unmixing problem), the derivation of their spatial distribution (mapping problem), and finally their study over time (multi-temporal analysis). The Moon Mineralogy Mapper on Chandrayaan-1 was a geophysical imaging spectrometer.
Background.
In 1704, Sir Isaac Newton demonstrated that white light could be split up into component colours. The subsequent history of spectroscopy led to precise measurements and provided the empirical foundations for atomic and molecular physics (Born & Wolf, 1999). Significant achievements in imaging spectroscopy are attributed to airborne instruments, particularly arising in the early 1980s and 1990s (Goetz et al., 1985; Vane et al., 1984). However, it was not until 1999 that the first imaging spectrometer was launched in space (the NASA Moderate-resolution Imaging Spectroradiometer, or MODIS).
Terminology and definitions evolve over time. At one time, >10 spectral bands sufficed to justify the term "imaging spectrometer" but presently the term is seldom defined by a total minimum number of spectral bands, rather by a contiguous (or redundant) statement of spectral bands.
The term hyperspectral imaging is sometimes used interchangeably with imaging spectroscopy. Due to its heavy use in military related applications, the civil world has established a slight preference for using the term imaging spectroscopy.
Unmixing.
Hyperspectral data is often used to determine what materials are present in a scene. Materials of interest could include roadways, vegetation, and specific targets (i.e. pollutants, hazardous materials, etc.). Trivially, each pixel of a hyperspectral image could be compared to a material database to determine the type of material making up the pixel. However, many hyperspectral imaging platforms have low resolution (>5m per pixel) causing each pixel to be a mixture of several materials. The process of unmixing one of these 'mixed' pixels is called hyperspectral image unmixing or simply hyperspectral unmixing.
Models.
A solution to hyperspectral unmixing is to reverse the mixing process. Generally, two models of mixing are assumed: linear and nonlinear.
Linear mixing models the ground as being flat and incident sunlight on the ground causes the materials to radiate some amount of the incident energy back to the sensor. Each pixel then, is modeled as a linear sum of all the radiated energy curves of materials making up the pixel. Therefore, each material contributes to the sensor's observation in a positive linear fashion. Additionally, a conservation of energy constraint is often observed thereby forcing the weights of the linear mixture to sum to one in addition to being positive. The model can be described mathematically as follows:
where formula_3 represents a pixel observed by the sensor, formula_4 is a matrix of material reflectance signatures (each signature is a column of the matrix), and formula_5 is the proportion of material present in the observed pixel. This type of model is also referred to as a simplex.
With formula_5 satisfying the two constraints:
1. Abundance Nonnegativity Constraint (ANC) - each element of x is positive.
2. Abundance Sum-to-one Constraint (ASC) - the elements of x must sum to one.
Non-linear mixing results from multiple scattering often due to non-flat surface such as buildings and vegetation.
Unmixing (Endmember Detection) Algorithms.
There are many algorithms to unmix hyperspectral data each with their own strengths and weaknesses. Many algorithms assume that pure pixels (pixels which contain only one materials) are present in a scene.
Some algorithms to perform unmixing are listed below:
Non-linear unmixing algorithms also exist: support vector machines or analytical neural network.
Probabilistic methods have also been attempted to unmix pixel through Monte Carlo unmixing algorithm.
Abundance Maps.
Once the fundamental materials of a scene are determined, it is often useful to construct an abundance map of each material which displays the fractional amount of material present at each pixel. Often linear programming is done to observed ANC and ASC.
Sensors.
Planned
Current and Past


PCB Piezotronics

PCB Piezotronics is a manufacturer of piezoelectric sensors.
The name "PCB" is abbreviation for "PicoCoulomB" which is technical terminology defining an electrical charge of the type generated by the piezoelectric sensors they manufacture. It is also a registered trademark of the company. "Piezotronics" combines the science of Piezoelectricity and electronics. PCB® manufactures sensors and related instrumentation. Sensors are small electromechanical instruments for the measurement of acceleration, dynamic pressure, force, acoustics, torque, load, strain, shock, vibration and sound.
History.
Founded by Robert W. Lally and James (Jim) F. Lally in 1967, PCB Piezotronics has evolved from a family business to a large company engineering and manufacturing operation, with technical emphasis on the incorporation of integrated circuit-piezoelectric sensor technology. In 1967 the integrated circuit piezoelectric sensor, also known as ICP sensors, incorporated microelectronic circuitry, were developed and marketed.
The 1970s for PCB Piezotronics saw expansion of its standard product offerings, to include other types of sensor technologies. In 1971, the company developed a 100,000 g high-shock, ICP® quartz accelerometer; Impulse Hammers for structural excitation were developed in 1972; and in 1973, the first rugged, industrial-grade ICP® accelerometer was introduced to serve the emerging machinery health monitoring market. Employment grew to 25 employees. By 1975, PCB® had become one of the largest U.S. manufacturers of piezoelectric sensors.
During the 1980s, PCB® continued to develop new products. In 1982, the Structural* Modal Array Sensing System was developed to ease sensor installation and reduce set-up time on larger-scale modal surveys. Modally-Tuned* Impulse Hammers won the IR-100 Award as one of the top 100 technical developments for 1983. The 128-channel Data Harvester was invented in 1984 to provide sensor power and speed modal analysis by offering automatic bank switching capability. In 1986, PCB developed the first commercial quartz shear-structured ICP® accelerometer. Additionally in 1980, PCB® broke ground on of land at 3425 Walden Avenue for its new quartz technology center, a location which it continues to occupy today. The facility doubled in size in 1985, and in 1996 an additional was added. An acre of land to the west of the building was purchased for future expansion and in 1999 a addition was completed.
In 1995, Underwriters Laboratory certified PCB to the International Quality Standard ISO-9001. In January 2002, The American Association for Laboratory Accreditation (A2LA) recognized PCB with accreditation to ISO 17025, an international standard for assuring technical competence in calibration and testing.
In 2015, Jim Lally was presented the lifetime achievement award at the 86th annual Shock and Vibration Symposium in Orlando. "This award recognized Jim Lally's 60 years of dedication to providing dynamic sensor technology in blast, ballistics, shock, vibration, acoustics, strain, and dynamic force to the SAVE community. It also recognizes both his generous contributions to educational institutions and his professionalism in corporate interactions."
PCB Group, Inc. was acquired by MTS Systems Corporation in July 2016 but retained its president David Hore and all its employees and facilities.
Divisions.
Today the company is organized into various divisions and product groups, and has representation in more than 60 countries worldwide. These divisions include PCB Automotive Sensors, based in Farmington Hills, Michigan; PCB Aerospace & Defense; IMI Sensors; and Larson Davis, based in Depew, NY. PCB product groups include Shock and Vibration; Microphones; Force; Pressure; and Electronics.


Selective school (New South Wales)

Selective schools in New South Wales, Australia are government high schools operated by the New South Wales Department of Education that accept their students based upon their academic merit.
Each year, approximately 15,000 Year 6 students across the state of New South Wales optionally undertake the Selective High Schools Test to seek one of the 3,600 places offered for first-year entry into selective high schools. For Year 8 to Year 12 entry into selective schools, students do not take an external test, however they can apply directly to a school for entry. The application package is standard to all government selective schools, with internal selection committees considering applications each year in August–September.
History.
The first government selective high schools in NSW were established in the late 19th and early 20th century. The selective school system at the turn of the 20th century included both schools newly established as selective schools, and older schools with selective entry that were brought into the system. The oldest selective schools included Bathurst High School, Fort Street High School, Goulburn High School, St. George Girls High School, Sydney Technical High School, Penrith High School and Sydney High School (now Sydney Boys High School and Sydney Girls High School). Many of the oldest selective schools in NSW have always been selective since establishment, including Fort Street (1849), Sydney Boys and Sydney Girls (1883), North Sydney Girls High School (1914), North Sydney Boys High School (1915), Hurlstone Agricultural High School (1959) and James Ruse Agricultural High School (1959).
Before World War II, most of the state's government high schools were selective. In 1957, a government report recommended the conversion of selective schools to comprehensive schools, reflecting changes in education philosophy. As a result, from the early 1960s, most selective schools were converted to comprehensive schools. The conversion was resisted by parents and influential alumni of especially inner-city selective schools such as Fort Street. As a result, a small number of selective schools survived the reforms: Fort Street, Sydney Boys, Sydney Girls, North Sydney Boys, North Sydney Girls, James Ruse and Hurlstone. However, in 1988, the NSW government began increasing the number of selective schools and also made an important reform, abolishing catchment restrictions for selective schools so that any student in NSW could apply to attend any selective school. In 1995, the NSW government under Bob Carr created some partially selective schools (i.e. schools with both comprehensive and selective streams).
In 2010, 14 more comprehensive high schools became partially selective, with one or more classes of selective students, and a "virtual school" bringing together a single class of students from regional NSW.
 there are 47 fully or partially selective government high schools, including 17 fully selective high schools (some of which are co-educational and other provide a single-sex educational environment; 25 partially selective high schools (high schools with both selective and comprehensive classes); four selective agricultural high schools; and one virtual selective high school. Of the 47 school, 34 are located in greater metropolitan Sydney.
The Aurora College is a virtual selective high school that caters for students enrolled in government high schools in rural or remote areas in New South Wales. Virtual classes commenced in January 2015 with over 160 students. The school is managed from administrative offices based in . Aurora allows students in rural and remote areas to remain in their local school and community while studying specialist subjects which their home school cannot currently offer. The College uses a range of technologies to access more fast-paced lessons delivered by video and interact with each other, and attend a residential program held twice per year.
Partially selective schools.
A number of schools have been designated as "partially selective", in that they have self-contained classes to provide for gifted and talented students in the junior years of high school. Often, schools combine selective and comprehensive streams as students enter the senior years, however, in practice, selective students tend to "self-select" into more advanced classes, such as extension units in Mathematics and English.
Admission and criteria.
Profile score.
In general, entry into a government selective school is determined by a "profile score", which is derived by combining school marks in English and mathematics with the marks received in the Selective High Schools Test in reading, writing, mathematics and general ability.
The profile score is computed by adding together component scores for English, mathematics and general ability, each of which are marks out of 100, to form the profile score out of 300.
 the component scores are computed as follows:
Scaling and moderating school and tests marks ensure that:
As For 2021, The NSW government has changed the test type to a 'Cambridge Style' Test.
This includes:
Thinking Skills: This is the predecessor of the then GA, which now has 40 questions in 40 minutes.
Mathematical Reasoning Skills: This is the predecessor of Maths, with 35 questions in 40 minutes.
Reading Skills: This is the predecessor of Reading, with 30 questions in 40 minutes.
Writing: Writing has increased to 30 minutes in time, as well as a different style in the stimulus.
The process also includes 'wild-score' processing which identifies students who, based on their school performance, may have done much worse than expected in the test. Where such students have been identified the moderating process takes this into account and adjusts scores accordingly. This ensures that students will not be disadvantaged by other students who attend the same school and may have done much worse than expected because of serious illness, misadventure or other cause.
Offers.
By early July students receive letters informing them of one of three outcomes concerning their application to each school:
In some cases, an application can be placed on 'hold', meaning it is awaiting the result of further enquiries by the Department of Education.
Other criteria.
Other criteria include age and grade, and current residency status in Australia. This usually requires students to be between 11 years and 5 months and 13 years at the start of the year they wish to commence Year 7, be in Year 6 the year before they wish to enter, and be either a citizen or permanent resident of Australia or a citizen of New Zealand. However, exemptions to some of these requirements may be given in special circumstances or through consultation with the Department of Education.
Debate.
The existence of government selective schools in NSW, which also exist in Victoria, Queensland and Western Australia, has not been without controversy, with much of it centred on the discrepancies between selective high schools and comprehensive high schools.
A significant dismantling of the selective schools system was proposed by an inquiry in 2002 that was funded by the NSW Parents and Citizens Association and the NSW Teachers Federation. At that time, the report called for the changing of 12 of the state's 19 selective high schools to partially selective high schools, retaining only the seven most established schools: Fort Street, North Sydney Boys', North Sydney Girls', Sydney Boys', Sydney Girls', Sydney Technical, and St George Girls'. The recommendation were justified, from the viewpoint of the inquiry's chair UNSW Professor Tony Vinson, by the fact that 'wherever possible, talented students should be able to remain within mainstream schools to maximise social cohesion and "an inclusive school community"'.
However, although the report had the backing of the then NSW Education Minister John Watkins, most of the Vinson enquiry's recommendations, including most of the recommendations concerning the status of selective schools, were not implemented by the NSW Government. Another report commissioned by the Department of Education, in 2005, drew on consultation with the public across the entire state school system and found that opinions are still polarised on whether they should continue to exist.
The debate has been reignited recently due to a string of articles from "The Sydney Morning Herald" criticising selective schools, with the main argument purporting that they are the cause of much socio-economic divide within Sydney.
In December 2018, the then NSW Minister for Education, Rob Stokes, announced the findings of the Review of Selective Education Access that outlined changes that aim to increase the number of girls, poor and disabled students, and students stronger in English than other subjects, in selective schools. The review found that:


Furlongs per fortnight


English Language Skills Assessment

The English Language Skills Assessment (ELSA) is a group of tests designed to measure English language proficiency of subjects. The test is designed for non-native speakers, with different levels of testing available from beginners to advanced.
The tests can be utilized to track progress among those studying English or to measure proficiency for employment or education where English language skills are required. The tests are intended for an international audience and are available in British English or American English. The tests are utilized by such educational organizations as the Australian Council for Educational Research to help predict student success and are compulsory at The University of the South Pacific. It is used by international businesses such as BASF, Unilever and DaimlerChrysler. Its usage is mandatory in Germany and Poland as part of the re-training programs for unemployed.
FELSA.
A variant of elsa, the Foundational English Language Skills Assessment (FELSA), has been developed for all age groups with a special focus on speakers who correspond to level A1 or A2 of the Common European Framework of Reference for Languages, who may have slight conversational English language familiarity but would not ordinarily be able to succeed in school, business or travel in English.


Chrony

chrony is an implementation of the Network Time Protocol (NTP). It's a replacement for the , which is a reference implementation of the NTP. It runs on Unix-like operating systems (including Linux and macOS) and is released under the GNU GPL v2. It's the default NTP client and server in Red Hat Enterprise Linux 8 and SUSE Linux Enterprise Server 15, and available in many Linux distributions.
Comparison with the reference implementation.
Unlike , chrony was implemented from scratch. It was designed to synchronize time even in difficult conditions such as intermittent network connections (such as laptops) and congested networks. Unlike , it supports synchronizing the system clock via hardware timestamping, improving accuracy of time synchronization between machines on a LAN. It also supports synchronization by manual input, and can perform time correction within an isolated network.


Xi Phoenicis

Xi Phoenicis, Latinized from ξ Phoenicis, is a visual binary star system in the southern constellation of Phoenix. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.70. Based upon an annual parallax shift of 14.61 mas as measured from Earth, it is located around 223 light years from the Sun. The system is moving away from the Sun with a radial velocity of about +10 km/s.
Primary star.
The primary is a chemically peculiar Ap star with a stellar classification of , where the suffix notation indicating the spectrum shows very strong lines of Strontium and Chromium. The star has about double the solar radius and is radiating 17 times the Sun's luminosity from its photosphere at an effective temperature of 8,300 K. Stellar evolution models indicate its properties are consistent with a mass of 1.91 times the solar mass and an age of 680 million years.
Xi Phoenicis has a strong magnetic field that varies with the stellar rotation period. It can be modeled as a dipolar field with a polar strength of , inclined by 88° in relation to the rotation axis of the star. The reconstruction of the stellar surface by Doppler imaging showed it is heterogenous with regions of different chemical abundances, which seem to be associated to the geometry of the magnetic field. For instance, lithium and oxygen have high abundances in the magnetic poles and low abundances in the magnetic equator, while elements like silicon and lanthanum are concentrated in a region between the magnetic equator and poles. However, these results have been contested, and it is possible the abundance maps are spurious due to the strong magnetic field.
An Alpha2 Canum Venaticorum variable, Xi Phoenicis's visual magnitude varies between 5.68 and 5.78 with a period of 3.9516 days, which is the rotation period of the star and is also associated with changes in the spectrum and the magnetic field. The brightness variation is maximum in the v band, with an amplitude of 0.13 magnitudes. The light curve in this band is symmetrical and has two distinct minima separated by half a rotation period, while the two maxima are igual. In other bands the variability is smaller or even absent, and doesn't show a regular pattern like in v. The star is similar in many aspects to rapidly oscillating Ap stars, but does not display the rapid pulsations typical of these stars.
Secondary star.
Xi Phoenicis is known as a double star since 1834, the date of the first registered observation in the Washington Double Star Catalogue. The relative position of the two components has remained constant to this day, confirming they have a common proper motion and form a physical binary system. The secondary star has a visual apparent magnitude of 9.95 and in 2007 was located at an angular separation of 13.06 arcseconds and position angle of 252.5°, in relation to the primary. Considering the distance to the system, this corresponds to a projected separation of 875 AU between the stars. The mass of the secondary is estimated at 0.81 times the solar mass.
This star is in the second catalogue of the Gaia spacecraft, which measured independently a distance equal to that of the primary, and estimated a radius of 0.76 , luminosity of 0.33 , and effective temperature of 5,000 K.


Nevada Test and Training Range

The Nevada Test and Training Range (NTTR) is one of two military training areas at the Nellis Air Force Base Complex in Nevada and used by the United States Air Force Warfare Center at Nellis Air Force Base. The NTTR land area includes a "simulated Integrated Air Defense System", several individual ranges with 1200 targets, and 4 remote communication sites. The current NTTR area and the range's former areas have been used for aerial gunnery and bombing, for nuclear tests, as a proving ground and flight test area, for aircraft control and warning, and for Blue Flag, Green Flag, and Red Flag exercises.
Geography.
The Nevada Test and Training Range land area is mostly Central Basin and Range ecoregion (cf. southernmost portion in the Mojave Desert), and smaller ecoregions (e.g., Tonopah Basin, Tonopah Playa, & Bald Mountain biomes) are within the area of numerous basin and range landforms of the NTTR.
Landforms.
The NTTR is at the serpentine section of the Great Basin Divide in southern Nevada and uses numerous landforms for military operations, e.g., Groom Lake near the northeast NTTR border is the airstrip for Area 51, the 1955 Site II west of the lake's WWII field. Tolicha Peak and Point Bravo are the sites of for electronic combat ranges, and the Mercury Valley is the eponym for a Cold War camp that became Mercury, Nevada. The Tonopah Test Range, within the boundaries of the NTTR (e.g., "Nellis Range 75") includes Antelope Lake, Radar Hill, and the "Cactus, Antelope, and Silverbow Springs".
Northern Range.
The "Northern Range" includes the Tolicha Peak Electronic Combat Range (TPECR, e.g., Range 76 targets 76-03, -05, -11, & -14) and Tonopah Electronic Combat Range (the Wildhorse Management Area encircled by the Northern Range is not part of the NTTR.)
Eastman Airfield Target.
The Eastman Airfield Target (Target 76-14, Korean Airfield, ) is a Range 76 target northwest of the TPECR. The target has a northeastern taxiway loop, characteristic for the former Soviet Air Force base at Jüterbog Airfield in East Germany, and three ramps in front of hangars on the western side of the loop. The other taxiways have a similar layout to Jüterbog, although the runway is about shorter. There are two accompanying SAM sites, one northwest of the airfield, and one northwest just like the original.
Southern Range.
The Southern Range includes the Point Bravo Electronic Combat Range. An area of about of the Southern Range that was withdrawn from the Desert National Wildlife Range is co-managed by the USAF and the USFWS.
Nearby facilities.
In addition to Nellis AFB, areas outside of the current NTTR land area are used for related activities, e.g., about of the former military range land (relinquished 1942, e.g. ranges 46-56, and ) is under the Nellis "Area A" airspace that is a Military Operations Area (MOA). The Formerly Used Defense Site north and northeast of the NTTR with "Stone Cabin, Hot Creek, Railroad, Tikaboo, and Sand Spring valleys" is a "former portion of the Tonopah Bombing Range", includes "Permit Required Confined space", and prohibits vehicles in "suspected ordnance impact area[s]" (e.g., "green markings" indicate chemical agents). Most areas adjacent to the NTTR are managed by the Bureau of Land Management for limited non-residential use such as grazing. Temporary sites, e.g., for Patriot Communications Exercises (about "21 days per exercise"), are in the "ADA activity area" east of the NTTR with 13 empty "500 feet by 500 feet" sites for mobile electronic equipment on BLM land in the "Sand Springs Valley, Coal Valley, Delamar Valley, and Dry Lake Valley" ("general area" of the Key Pittman WMA) and "under MOA airspace".
History.
"Tertiary age" lava flows formed 5 erupted groups in the area, and block faulting such as the Siebert and Mizpah faults formed the ranges and valleys. Precambrian and Paleozoic marine sediments form an "almost uniform thickness of 40,000 feet", and surface geology is "typically the Cenozoic Era continental deposits and some Paleogene volcanic rocks". Located at the southern tip of the Great Basin tribes area, the eventual range area was crossed by the Old Spanish Trail (trade route), was south of the Pony Express route, and was split by the 37th parallel north of the 1850 New Mexico & 1863 Arizona territories' northwest corner. In the 1930s the land had been used as an Animal Sanctuary where the Department of the Interior made it a wildlife reservation. However, in 1942 during World War II the region restricted it from public access for the War Department to use. The original bombing range had been used for the 1900–1921 silver rush (e.g., Tonopah Mining District & Tonopah Manhattan Stage Route), and the region was subdivided into smaller numbered management areas (e.g., Area 2, Area 5, Area 11, Area 12, Area 25, Area 27, Area 52), which are used for names of some of the range installations (e.g., "Area 3 Compound" and "Area 51" for "Groom Lake Field").
Tonopah Bombing Range.
The Tonopah Bombing Range was designated on federal land "withdrawn ... October 29, 1940, from the public domain" and in June 1941, the "Tonopah Gunnery and Bombing Range" was split at "37 degrees and 30 minutes" latitude into the "Tonopah General Range" and "Las Vegas General Range". On October 28, 1941, "United States v. 1,855,720 Acres of land ..." (US Fifth District) was initiated to seize private land, and in July 1942 the Fourth Air Force Bombing and Gunnery Range Detachment from "Muroc Lake" arrived as the 1st unit. Several Nevada World War II Army Airfields were established, e.g., the August 1942 Tonopah Army Air Field in the north area and in the south, Indian Springs Auxiliary Army Airfield and its additional fields, e.g., at Area 18 (Aux. Field#4) and Area 51 (Aux. Field#1). In February 1943, Indian Springs AAF was being used for the 82d Flying Training Wing for air-to-air gunnery training, and Indian Springs AAF closed in January 1947. In June 1947 Tonopah AAF was declared excess along with its 3 auxiliary areas (Mizpah and Butler housing terraces and Columbia Junction gasoline unloading station). The Indian Springs main facility re-opened in January 1948 and on June 13, 1949, Air Training Command merged the Las Vegas Bombing and Gunnery Range and the Tonopah Bombing and Gunnery Range. On June 28, 1949, the "Gunnery Range of the Tonopah Air Force Base" had about and after the 1949 Las Vegas Air Force Base was renamed on April 30, 1950, an Atomic Energy Commission committee selected the for a nuclear test site on December 12, 1950. The land was ideal for training aerial gunners because the land was far from people and contained dry lake beds, which worked perfectly for target practices.
Nellis Air Force Gunnery and Bombing Range.
A 680-square mile section of the Nellis Air Force Gunnery and Bombing Range was designated the Nevada Proving Grounds (NPG) on December 18, 1950. The new NPG included "Yucca and Frenchman Flats, Paiute and Rainier Mesas". The presidential order also established Groom Lake Field (colloq. "The Pig Farm") at the WWII installation. The first NPG nuclear test was for Operation Ranger on January 27, 1951, and the Indian Springs main facility (renamed an Air Force Base in 1951) supported NPG testing after ARDC General Order No. 39 on July 16, 1952. The NPG "military support facility" (now the private Desert Rock Airport) operated September 1951-October 7, 1957 (electricity was from AEC's Camp Mercury) and closed June 18, 1964. In 1955 on the southwest corner of Groom Lake, a survey team laid out the 5,000-foot (1,500 m) north–south "Site II" runway for Project AQUATONE. The 1st Lockheed U-2 (Article 341) left the Skunk Works in a C-124 cargo plane for the AQUATONE site in July 1955 and first flew on July 29 during a runway test. The Tonopah Test Range (TTR) land was withdrawn from public use in 1956 to replace nuclear test sites at the "Salton Sea Test Base" and the Yucca Flat site, and in 1957 Sandia Laboratories began TTR operations at Cactus Flat.
From 1956-1969/70, the Las Vegas Air Force Station and Tonopah Air Force Stations provided Reno Air Defense Sector radar tracks and in 1957, the "instrumented AEC range at Tonopah" was used by NAS Fallon and Point Mugu pilots. "A safety experiment (Project 57 No. 1) with ground zero coordinates of N 932646, E 688515 was detonated on April 24, 1957" in "Area 13" at the northeast NTTR boundary. In 1958, the Tonopah Test Range Airport was planned with a single runway of . In 1960, Camp Mercury was a base camp for Project 5.5 that studied nuclear detonation effect on the Northrop F-89D Scorpion (a similar Project 6.5 was for effect of nuclear detonations on the Nike Hercules missile system). A 1961 Public Land Order transferred USAF land to the AEC, and after the 1962 RBS Express #2 near the Hawthorne Naval Ammunition Depot was used for Radar Bomb Scoring of flights over the range, the Hawthorne Bomb Plot radar station operated in Babbitt until . Operation Roller Coaster was a TTR nuclear test series in May and June 1963 and in November and December 1965, B-52 Combat Skyspot testing at the range used the only CONUS AN/MSQ-77 developed for the Vietnam War. Planning to integrate the range with the Fallon and Hill/Wendover/Dugway ranges to create the Great Basin's "Continental Operations Range" ended in 1975, the 1st year for a Nellis range Red Flag exercise.
Nellis Air Force Range.
The Nellis Air Force Range (NAFR) was used to bury wreckage of the 1978 Groom Lake & 1979 NAFR Lockheed F-117 Nighthawk crashes, and additional Cold War accidents at the range included the 1975 NAFR TR-1 crash, the 1979 Tonopah MiG-17 crash during training versus an Northrop F-5, the 1984 Little Skull Mountain MiG-23 crash, which killed a USAF general, and the 1986 NAFR crash, which "Air Force sources" identified as an "F-19" stealth fighter. Circa 1980, NAFR received 806L "Range Threat" systems for electronic warfare simulation and from 1983 to 1985, the area of South Antelope Lake was used for two Tomahawk missile targets. NAFR range operations transferred to the 99th Range Group at the end of the Cold War (the range received various Radar Bomb Scoring electronic systems from Strategic Training Ranges, e.g., Nellis had 5 AN/MSQ-77s by 1994). In 1999 the range's land withdrawal was renewed and the unused portion of the original Tonopah Bombing Range was redesignated a Formerly Used Defense Site.
In 2001, NAFR was renamed the Nevada Test and Training Range (NTTR) and in October 2001, the range group personnel and assets for range operations transferred to the 98th Range Wing. In 2005, Indian Springs AFAF was renamed Creech Air Force Base and in 2010, the NTS was renamed the Nevada National Security Site. The NTTR had four tracts in the 2010 U.S. Census. In 2011, the 98th Range Wing was redesignated with the same name as the range (NTTR).
Area 51 Facebook Raid.
In June 2019, a joke Facebook event was created rallying the public to storm the training range on September 20 that year, saying "Let's see them aliens". Over two million people responded as "going" to the event, with another 1.5 million "interested". The county commission chairman estimated that approximately 40,000 people would turn up on 20 September.
On July 10, speaking with "The Washington Post", Air Force spokeswoman Laura McAndrews said officials were aware of the event, and issued a warning saying that the area was "an open training range for the U.S. Air Force, and we would discourage anyone from trying to come into the area where we train American armed forces", adding: "The U.S. Air Force always stands ready to protect America and its assets". A public information officer at Nellis Air Force Base told KNPR that "any attempt to illegally access the area is highly discouraged".


CUSPEA

CUSPEA (China-U.S. Physics Examination and Application) was an examination and admission system used by the physics departments of some American and Canadian universities for graduate school admission from People's Republic of China between 1979 and 1989.
It was created by the Chinese-American physicist Tsung-Dao Lee and Chinese physics community as an alternative graduate school admission procedure. At that time in China, higher education was still recovering from the Cultural Revolution; school transcripts and recommendation letters were difficult to evaluate. Furthermore, standardized tests such as the Graduate Record Examination were unavailable in China.
Details.
The CUSPEA exam is in English and has a similar scope to that of Ph.D. written qualifying exams in major American universities. The questions were prepared by physics professors from participating North American universities -- starting with Columbia University where Lee worked, and eventually expanded to 97 universities. Committees of physicists in China administer and grade the exams. The examinees are usually senior physics majors from top-ranking Chinese universities. Those who passed the exam are followed up by an interview by a small American delegation. The final admission depends on mutual agreement between the applicant and participating physics departments.
About 100 Chinese students went to the US every year through the CUSPEA exams, and the total number is 915. Over the years, the three universities with the most students passed the exam are (numbers in the parentheses indicate the numbers of students) University of Science and Technology of China (218), Peking University (206) and Fudan University (127).
Similar Exams.
CUSPEA was so successful that other similar exams soon were created, such as CUSBEA for biochemistry and "Shiing-Shen Chern Project" (陈省身项目) for mathematics. All were stopped in the late 80s in favor of more standard exams.
Continuation as Mini-CUSPEA and Re-Expansion.
In the early 1990s, several years after the suspension of the CUSPEA exam, a new program called Mini-CUSPEA was created. The new program name referred to the fact that only one Chinese university, namely Fudan University, was now involved. Likewise, in the U.S., the number of target universities had been shrunk to three - Columbia University, New York University, and the City University of New York.
Mini-CUSPEA applicants sit written exams and attend interviews, similar in style to the old CUSPEA admission tests. Around 6-10 students are admitted annually. The usual requirements (TOEFL and GRE) for Chinese students studying in the U.S are waived for successful Mini-CUSPEA applicants.
Since 2007, the Mini-CUSPEA program has started to expand. The Chinese universities involved now include Peking University, Tsinghua University and other top universities. Expansion is also planned on the U.S. side.


760 Massinga

760 Massinga ("prov. designation:" "or" ) is a large background asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered by German astronomer Franz Kaiser at the Heidelberg Observatory on 28 August 1913. The stony S-type asteroid has a rotation period of 10.7 hours and is somewhat elongated in shape. It was named in memory of Adam Massinger (1888–1914), a German astronomer at Heidelberg who was killed in World War I.
Orbit and classification.
"Massinga" is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the outer asteroid belt at a distance of 2.4–3.9 AU once every 5 years and 7 months (2,039 days; semi-major axis of 3.15 AU). Its orbit has an eccentricity of 0.23 and an inclination of 13° with respect to the ecliptic.
Discovery.
"Massinga" was discovered by Franz Kaiser at the Heidelberg-Königstuhl State Observatory in southwest Germany on 28 August 1913. On the same night, it was independently discovered by Russian astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula. The Minor Planet Center, however, only credits Franz Kaiser with the discovery. The body's observation arc begins at Heidelberg on 8 November 1914, more than a year after its official discovery observation.
Naming.
This minor planet was named after Adam Massinger (1888–1914), a German astronomer and discoverer of minor planets at Heidelberg who died in the First Battle of Ypres during World War I on 21 October 1914. An obituary was published by Max Wolf in the astronomical journal "Astronomische Nachrichten". The was mentioned in "The Names of the Minor Planets" by Paul Herget in 1955 ().
Physical characteristics.
In the Tholen classification, "Massinga" is a common, stony S-type asteroid, though with an unusual spectrum (SU), while in the Tholen- and SMASS-like taxonomic variants of the Small Solar System Objects Spectroscopic Survey (S3OS2), it is an S-type and SL-type, latter which transitions to the uncommon L-type, respectively.
Rotation period.
In December 1999, a rotational lightcurve of "Massinga" was obtained from photometric observations by Robert A. Koff at his observatory in Colorado. Lightcurve analysis gave a rotation period of hours with a brightness variation of magnitude (). In March 2006, Laurent Bernasconi and Rui Goncalves determined a similar period of hours and an amplitude of magnitude ().
Diameter and albedo.
According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the Japanese Akari satellite, and the Infrared Astronomical Satellite IRAS, "Massinga" measures (), () and () kilometers in diameter and its surface has an albedo of (), () and (), respectively. The "Collaborative Asteroid Lightcurve Link" derives an albedo of 0.2392 and a diameter of 71.47 kilometers based on an absolute magnitude of 7.9.
On 29 February 2012, an asteroid occultation of "Massinga" gave a best-fit ellipse dimension of (), with a high quality rating of 3. These timed observations are taken when the asteroid passes in front of a distant star.


The Private Life of a Cat

The Private Life of a Cat is a 22-minute 1947 black and white experimental documentary film by Alexander Hammid and Maya Deren.Archive.org summarises that the film is an "intimate study" of a female cat who gives birth to a litter of kittens and shows their maturation.
Synopsis.
The film is entirely silent and shot from the cat's eye-level; "He", an all white short-haired male cat, grooms "She", a fluffier female. After two months they find a spot "for the family", and soon after the mother goes into labour. The film shows graphically the kittens being born without the help of human hands, and then getting nursed and washed by their mother. The kittens grow, and the parent cats roam freely around their owners' apartment (Hammid and Deren). The kittens learn how to walk and begin to get more active, playing with each other and clawing various furniture. The film then ends by showing the same scene from the beginning where "He" courts "She".
Reputation.
Top Documentary Films rates "The Private Life of a Cat" 7.70/10 stars, saying that it is "very touching", and that it is "[b]eautifully photographed and executed. With subtitles, no dialog, and a refreshing absence of human beings on screen." Dangerous Minds wrote "[t]his beautiful 1944 silent film from husband-and-wife team Maya Deren and Alexander Hammid is quite possibly the only evidence we need that cats are the ultimate well-spring of creativity."


Agnes Berger

Agnes P. Berger (1916-2002) was a Hungarian-American mathematician who served as an associate professor of biostatistics at Columbia University's School of Public Health, as well as a statistical consultant at Mount Sinai.
Early years.
Her first experiences with mathematics were thanks to the Hungarian publication Kömal (Kozepiskolai Matematikai Lapok), a monthly magazine for high school students that included math problems.
During her studies at the University of Budapest, she was a student of the prominent Hungarian mathematician Lipót Fejér, whom she would remember years later for his short, detailed classes and dramatic endings. Her parents were friends with the parents of contemporary mathematician Peter Lax.
She earned her doctorate.
Career.
Berger collaborated with other statisticians such at Jerzy Neyman. She reviewed work of Joseph L. Fleiss, another statistical mathematician.
Family life and last years of life.
Agnes Berger married Laszlo Berger, with whom she had a son, John Joseph Berger. She died at age 85 at Lenox Hill Hospital on March 27, 2002.


South African units of measurement

A number of units of measurement were used in South Africa to measure quantities like length, mass, capacity, etc. The Imperial system of measurements was made standard in 1922 and the metric system was adopted in 1970.
System before metric system.
British and old Dutch systems were used.
Length.
The Rhynland rood ("Rijnlandse roede") was a standard Dutch measurement. It was changed in 1859 to the "Cape Foot" due to a drift in standards.
Mass.
One bundle was equal to 0.699 (≈0.7) lbs. [].
Area.
One morgen was equal to .
Capacity.
Several units were used. Some units are provided below:
Dry measures.
These were used to measure rice and salt.
Corn measures.
These were used to measure grain.
Liquid measures.
The country didn't have a unified system of liquid measurement in the 19th century because the Afrikaners used the Dutch gallon and the British used the Imperial gallon. When measuring alcohol, the British system was used only for ale and beer and the Dutch system was used only for wine, brandy and distilled spirits. This was due to specialization in the two colonies, which were not united until 1910. Vintning was more common among the Boer farmers of the Western Cape, who dominated the industry. Meanwhile, the British farmers grew grain that could be brewed into beer. Wine was for export and beer, which was perishable, was for domestic consumption. Each community used their own standard measurement systems to store, sell and ship their wares.
Ale & beer.
The "firkin", "kilderkin", barrel, "hogshead", and "butt" were traditional British measurements of capacity for standard ale and beer containers. They were based on the British ale gallon. (Once there were different measures for ale and beer before the Ale gallon measure became standard for both in 1688; the Ale gallon then became the Imperial gallon in 1824).
Beer bottles in South Africa were different than in other countries.
Wine.
The Dutch East India company used the Cape of Good Hope as a waystation between Europe and the East Indies in the 17th and 18th centuries. Dutch sailors drank the local wine to combat scurvy and exported barrels of it back to Europe. This was followed by the British government's policy of encouraging the wine and brandy industry in South Africa in the early- to mid-19th century through subsidies and low tariffs. (Their recent isolation during Napoleon's Continental System impressed upon them that they would potentially need alternative sources of European commodities in the future.)
The "kanne", "anker", "ahm", and "legger" are obsolete 17th century Dutch measurements of capacity that were used for standard containers of wine and spirits. The standard "Dutch gallon" used was based on that of Amsterdam. They were typically sold in "ankers", half-aums, and "leggers" until 1922, when the Imperial measurement system went into effect.
Gasoline.
Gasoline was formerly sold in Imperial gallons [1 Imp. gal. = 4.55 l], but was switched to litres after the adoption of the metric system.


Rebecca Doerge

Rebecca Whitbeck Doerge is an American researcher in statistical bioinformatics, known for her research on quantitative traits. Formerly the Trent and Judith Anderson Distinguished Professor of Statistics at Purdue University, she is currently the dean of the Mellon College of Science at Carnegie Mellon University, with joint appointments in the departments of biology and statistics.
Education and career.
Doerge was born in Stamford, New York. After graduating in mathematics from the University of Utah in 1986, she earned a master's degree in statistics from Utah in 1988, advised there by Simon Tavaré. She then completed a Ph.D. in statistics from North Carolina State University in 1993. Her dissertation, supervised by Bruce Weir, was "Statistical Methods for Locating Quantitative Trait Loci with Molecular Markers".
After postdoctoral research with Gary Churchill at Cornell University, Doerge joined the Purdue University faculty in 1995. She chaired the Department of Statistics there from 2010 to 2015, and was appointed as Anderson Distinguished Professor in 2011. She moved to Carnegie Mellon to become dean in 2016.
Awards and honors.
Doerge became a fellow of the American Association for the Advancement of Science and of the American Statistical Association in 2007.


4786 Tatianina

4786 Tatianina, provisional designation , is a bright background asteroid and synchronous binary system from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 13 August 1985, by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. It was named after Tatiana Somova, a friend of the discoverer. The E-/Xc-subtype has a short rotation period of 2.9 hours. Its sub-kilometer minor-planet moon was discovered on 20 March 2006 and announced the following month.
Orbit and classification.
"Tatianina" is a non-family asteroid from the main belt's background population. It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.8 AU once every 3 years and 7 months (1,322 days; semi-major axis of 2.36 AU). Its orbit has an eccentricity of 0.19 and an inclination of 7° with respect to the ecliptic.
The asteroid was first observed as at the Algiers Observatory in April 1948. The body's observation arc begins at Nauchnij in May 1970 as , more than 15 years prior to its official discovery observation.
Physical characteristics.
In the SMASS classification, "Tatianina" is a Xc-subtype that transitions from the X-type to the carbonaceous C-type asteroids. It has also been characterized as a bright E-type by the Wide-field Infrared Survey Explorer (WISE).
Rotation period.
Several rotational lightcurves of "Tatianina" have been obtained from photometric observations since 2003 (). Analysis of the best-rated lightcurve from March 2003, during which a satellite was also discovered "(see below)", gave a rotation period of 2.9227 hours with a brightness amplitude of 0.19 and 0.20 magnitude ().
Diameter and albedo.
According to the survey carried out by the NEOWISE mission of NASA's WISE telescope, "Tatianina" measures between 3.282 and 3.475 kilometers in diameter and its surface has an exceptionally high albedo of 0.4763 to 0.514. The "Collaborative Asteroid Lightcurve Link" adopts the revised WISE-data by Petr Pravec, that is an albedo of 0.4763 and rounded diameter of 3.48 kilometers based on an absolute magnitude of 13.718.
Satellite.
During the photometric observations by Donald Pray, Petr Pravec and collaborators in March 2006, it was revealed that "Tatianina" is a synchronous binary asteroid with a minor-planet moon orbiting it every 21.67 hours at an estimated average distance of . The discovery was announced on 11 April 2006. The mutual occultation events suggest the presence of a satellite with an estimated diameter of meters or 19% the size of its primary.
Numbering and naming.
This minor planet was numbered on 28 April 1991. It was named by the discoverer after Tatiana Aleksandrovna Somova, a nursery-school teacher in Saint Petersburg, Russia. The official naming citation was published by the Minor Planet Center on 5 March 1996 ().


Celsius

The degree Celsius is a unit of temperature on the Celsius scale, a temperature scale originally known as the centigrade scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. Before being renamed to honor Anders Celsius in 1948, the unit was called "centigrade", from the Latin "centum", which means 100, and "gradus", which means steps.
Since 1743 the Celsius scale has been based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure. Prior to 1743 the values were reversed (i.e. the boiling point was 0 degrees and the freezing point was 100 degrees). The 1743 scale reversal was proposed by Jean-Pierre Christin.
By international agreement, between 1954 and 2019 the unit and the Celsius scale were defined by absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW), a precisely defined water standard. This definition also precisely related the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature with symbol K. Absolute zero, the lowest temperature possible, is defined as being exactly 0 K and −273.15 °C. Until 19 May 2019, the temperature of the triple point of water was defined as exactly . This means that a temperature difference of one degree Celsius and that of one kelvin are exactly the same.
On 20 May 2019, the kelvin was redefined so that its value is now determined by the definition of the Boltzmann constant rather than being defined by the triple point of VSMOW. This means that the triple point is now a measured value, not a defined value. The newly-defined exact value of the Boltzmann constant was selected so that the measured value of the VSMOW triple point is exactly the same as the older defined value to within the limits of accuracy of contemporary metrology. The degree Celsius remains exactly equal to the kelvin, and 0 K remains exactly −273.15 °C.
History.
In 1742, Swedish astronomer Anders Celsius (1701–1744) created a temperature scale that was the reverse of the scale now known as "Celsius": 0 represented the boiling point of water, while 100 represented the freezing point of water. In his paper "Observations of two persistent degrees on a thermometer", he recounted his experiments showing that the melting point of ice is essentially unaffected by pressure. He also determined with remarkable precision how the boiling point of water varied as a function of atmospheric pressure. He proposed that the zero point of his temperature scale, being the boiling point, would be calibrated at the mean barometric pressure at mean sea level. This pressure is known as one standard atmosphere. The BIPM's 10th General Conference on Weights and Measures (CGPM) in 1954 defined one standard atmosphere to equal precisely 1,013,250 dynes per square centimeter (101.325 kPa).
In 1743, the Lyonnais physicist Jean-Pierre Christin, permanent secretary of the Academy of Lyon, inverted the celsius scale so that 0 represented the freezing point of water and 100 represented the boiling point of water. Some credit Christin for independently inventing the reverse of Celsius' original scale, while others believe Christin merely reversed Celsius' scale. On 19 May 1743 he published the design of a mercury thermometer, the "Thermometer of Lyon" built by the craftsman Pierre Casati that used this scale.
In 1744, coincident with the death of Anders Celsius, the Swedish botanist Carl Linnaeus (1707–1778) reversed Celsius's scale. His custom-made "linnaeus-thermometer", for use in his greenhouses, was made by Daniel Ekström, Sweden's leading maker of scientific instruments at the time, whose workshop was located in the basement of the Stockholm observatory. As often happened in this age before modern communications, numerous physicists, scientists, and instrument makers are credited with having independently developed this same scale; among them were Pehr Elvius, the secretary of the Royal Swedish Academy of Sciences (which had an instrument workshop) and with whom Linnaeus had been corresponding; , the instrument maker; and Mårten Strömer (1707–1770) who had studied astronomy under Anders Celsius.
The first known Swedish document reporting temperatures in this modern "forward" Celsius scale is the paper "Hortus Upsaliensis" dated 16 December 1745 that Linnaeus wrote to a student of his, Samuel Nauclér. In it, Linnaeus recounted the temperatures inside the orangery at the University of Uppsala Botanical Garden:
Centigrade versus Celsius.
Since the 19th century, the scientific and thermometry communities worldwide have used the phrase "centigrade scale" and temperatures were often reported simply as "degrees" or, when greater specificity was desired, as "degrees centigrade", with the symbol °C.
However, the term "centigrade" was also used in the Spanish and French languages as a unit of angular measurement (1/100 of a right angle), and it had a similar connotation in other languages. The term "centesimal degree" or "gradian" ("grad" or "gon": 100g = 90°, 1g = 0.9°) was used when unambiguous language was required by international standards bodies such as the BIPM. It would more properly now be called "hectograde".
To eliminate confusion between the unit of temperature and the unit of angular measurement, the 9th meeting of the General Conference on Weights and Measures and the Comité International des Poids et Mesures (CIPM) formally adopted "degree Celsius" in 1948 for the degree of temperature, and kept the recognized degree symbol (), rather than adopting the gradian/centesimal degree symbol (g or gon).
For scientific use, "Celsius" is the term usually used, but in English-speaking countries "centigrade" remains in common use, especially in informal contexts. It was not even until February 1985 that the weather forecasts issued by the BBC switched the term from "centigrade" to "Celsius".
Common temperatures.
Some key temperatures relating the Celsius scale to other temperature scales are shown in the table below.
Name and symbol typesetting.
The "degree Celsius" has been the only SI unit whose full unit name contains an uppercase letter since 1967, when the SI base unit for temperature became the kelvin, replacing the capitalized term "degrees Kelvin". The plural form is "degrees Celsius".
The general rule of the International Bureau of Weights and Measures (BIPM) is that the numerical value always precedes the unit, and a space is always used to separate the unit from the number, (not " or "). The only exceptions to this rule are for the unit symbols for degree, minute, and second for plane angle (°, ′, and ″, respectively), for which no space is left between the numerical value and the unit symbol. Other languages, and various publishing houses, may follow different typographical rules.
Unicode character.
Unicode provides the Celsius symbol at code point . However, this is a compatibility character provided for roundtrip compatibility with legacy encodings. It easily allows correct rendering for vertically written East Asian scripts, such as Chinese. The Unicode standard explicitly discourages the use of this character: "In normal use, it is better to represent degrees Celsius "°C" with a sequence of + , rather than . For searching, treat these two sequences as identical."
Temperatures and intervals.
The degree Celsius is subject to the same rules as the kelvin with regard to the use of its unit name and symbol. Thus, besides expressing specific temperatures along its scale (e.g. "Gallium melts at 29.7646 °C" and "The temperature outside is 23 degrees Celsius"), the degree Celsius is also suitable for expressing temperature "intervals": differences between temperatures or their uncertainties (e.g. "The output of the heat exchanger is hotter by 40 degrees Celsius", and "Our standard uncertainty is ±3 °C"). Because of this dual usage, one must not rely upon the unit name or its symbol to denote that a quantity is a temperature interval; it must be unambiguous through context or explicit statement that the quantity is an interval. This is sometimes solved by using the symbol °C (pronounced "degrees Celsius") for a temperature, and C° (pronounced "Celsius degrees") for a temperature interval, although this usage is non-standard. Another way to express the same is , which can be commonly found in literature.
Celsius measurement follows an interval system but not a ratio system; and it follows a relative scale not an absolute scale. For example, an object at 20 °C does not have twice the energy of when it is 10 °C; and 0 °C is not the lowest Celsius value. Thus, degrees Celsius is a useful interval measurement but does not possess the characteristics of ratio measures like weight or distance.
Coexistence of Kelvin and Celsius scales.
In science and in engineering, the Celsius scale and the Kelvin scale are often used in combination in close contexts, e.g. "a measured value was 0.01023 °C with an uncertainty of 70 μK". This practice is permissible because the magnitude of the degree Celsius is equal to that of the kelvin. Notwithstanding the official endorsement provided by decision no. 3 of Resolution 3 of the 13th CGPM, which stated "a temperature interval may also be expressed in degrees Celsius", the practice of simultaneously using both °C and K remains widespread throughout the scientific world as the use of SI-prefixed forms of the degree Celsius (such as "μ°C" or "microdegrees Celsius") to express a temperature interval has not been well adopted.
Melting and boiling points of water.
The melting and boiling points of water are no longer part of the definition of the Celsius scale. In 1948, the definition was changed to use the triple point of water. In 2005 the definition was further refined to use water with precisely defined isotopic composition (VSMOW) for the triple point. In 2019, the definition was changed to use the Boltzmann constant, completely decoupling the definition of the kelvin from the properties of water. Each of these formal definitions left the numerical values of the Celsius scale identical to the prior definition to within the limits of accuracy of the metrology of the time.
When the melting and boiling points of water ceased being part of the definition, they became measured quantities instead. This is also true of the triple point.
In 1948 when the 9th General Conference on Weights and Measures (CGPM) in Resolution 3 first considered using the triple point of water as a defining point, the triple point was so close to being 0.01 °C greater than water's known melting point, it was simply defined as precisely 0.01 °C. However, later measurements showed that the difference between the triple and melting points of VSMOW is actually very slightly (<0.001 °C) greater than 0.01 °C. Thus, the actual melting point of ice is very slightly (less than a thousandth of a degree) below 0 °C. Also, defining water's triple point at 273.16 K precisely defined the magnitude of each 1 °C increment in terms of the absolute thermodynamic temperature scale (referencing absolute zero). Now decoupled from the actual boiling point of water, the value "100 °C" is hotter than 0 °C – in absolute terms – by a factor of "precisely" (approximately 36.61% thermodynamically hotter). When adhering "strictly" to the two-point definition for calibration, the boiling point of VSMOW under one standard atmosphere of pressure was actually 373.1339 K (99.9839 °C). When calibrated to ITS-90 (a calibration standard comprising many definition points and commonly used for high-precision instrumentation), the boiling point of VSMOW was slightly less, about 99.974 °C.
This boiling-point difference of 16.1 millikelvins between the Celsius scale's original definition and the previous one (based on absolute zero and the triple point) has little practical meaning in common daily applications because water's boiling point is very sensitive to variations in barometric pressure. For example, an altitude change of only 28 cm (11 in) causes the boiling point to change by one millikelvin.


EF Standard English Test

The EF Standard English Test is a standardized test of the English language designed for non-native English speakers. It is the product of EF Education First, a global language training company, and a team of language assessment experts including Lyle Bachman, Mari Pearlman, and Ric Luecht. EF compares the EFSET's accuracy to the most widely used high stakes standardized English tests: TOEFL, IELTS, and Cambridge International Examinations.
There are three versions of the EFSET: a 15-minute test ("EFSET Quick English Check"), a 50-minute test which assigns a score on the 6-level Common European Framework of Reference for Languages ("EFSET English Certificate"), and a 2-hour test which assigns a score from 0 to 100 with a TOEFL and IELTS equivalency score in addition to the 6-level CEFR score ("EFSET English Certificate Plus"). All test versions assess receptive skills only (reading and listening comprehension) and do not assess writing or speaking Unlike other standardized English tests, the EFSET uses computerized adaptive testing methods to adjust the difficulty of the test according to the examinee's ability level. The EFSET is not a proctored exam.
Test launch.
EF Education First initially intended to build the EFSET for internal use as a low-cost alternative to third party standardized English tests, with the aim of attaining the same level of accuracy as those tests. Soon, the company realized it could gain branding benefits from releasing a robust, testing tool for any English learner to use. The initial public launch of the EFSET in 2014 was the result of a 3-year process, which included 15 months of formal trials involving 14,500 students.
Scoring.
The EFSET English Certificate Plus is scored on a scale of 0 to 100 with a separate score attributed for reading and listening as well as an overall score. EFSET English Certificate Plus scores are mapped to the 6-level CEFR bands from A1 to C2 as well as to IELTS and TOEFL scores as shown in the table below.


Foundation Insurance Test

The Foundation Insurance Test (FIT) is an insurance qualification in the United Kingdom. The Foundation Insurance Test is considered an entry-level qualification for those beginning insurance careers and is usually taken before advancing to more demanding examinations such as the CII exams. The exam is multiple choice and in 2012 the exam had a pass rate of 78.43%. A nominal pass mark is set at 70% although the actual pass mark may vary.
The test covers several areas of insurance:


260 Huberta

Huberta (minor planet designation: 260 Huberta) is a large asteroid orbiting near the outer edge of the Main belt. It is dark and rich in carbon.
It belongs to the Cybele group of asteroids and may have been trapped in a 4:7 orbital resonance with Jupiter.
It was discovered by Johann Palisa on 3 October 1886 in Vienna and was named after Saint Hubertus.


Microphone stand

A microphone stand is a free-standing mount for a microphone. It allows the microphone to be positioned in the studio, on stage or on location without requiring a person to hold it.
The most basic microphone stand is a "straight stand". It uses a dome-shaped round metal base, or a tripod base, into which is threaded a post for mounting the microphone (most commonly a 5/8-27 threaded hole). This post may be made up of two or more telescoping tubes that fit inside each other, allowing for quick height adjustment. The mechanism for adjusting the height is called the clutch.
There are various versions of the straight stand known as the "desk stand" (short version of straight stand) and heavy duty microphone stand (heavier base and larger tubes) to handle heavy microphones. The tubes used on the straight stand usually have a shiny chrome plating to resist scratching, but may also be finished in a matte black.
A very popular updated version of the straight stand uses the "folding tripod base stand", instead of the round, domed metal base. This folding base allows for easier packing of the stand when moving from location to location and reduces the weight of the stand. However, to compensate for the lack of weight at the base while still maintaining stability, the three "feet" of the tripod must extend out beyond the radius of a round base. The trade-off is that these "feet" may become a trip-hazard on a dark stage.
A number of accessories make microphone stands more useful. Most of these are designed to get the microphone closer to the user without placing the upright portion of the stand directly in front of the performer.
A "boom arm" attaches to the top of the stand so the microphone can move in the horizontal plane. A guitar player, for example, might use this to place the microphone directly in front of his mouth without having the upright portion of the stand in the way of the guitar. It also lets musicians have the microphone closer to the sound source when floor space is at a premium. This can be particularly useful when placing microphones on a drum stand when the microphone stands must compete for space with things like cymbal stands. Boom arms are offered both in fixed length and adjustable (telescoping) lengths.
Another handy device for adjusting microphone placement is a flexible "goose neck" tube. Made of a spiral-wound core of steel, goosenecks are made in various lengths and finishes and provide the ability to make minute changes in microphone position.
Microphones typically attach to the stand via a detachable microphone holder screwed to the end of the boom. (Some microphones screw directly onto the boom.) Commonly used screw threads (from large to small) are:
Various male/female adapters are available to connect dissimilar sizes. Note: A compatible ¼″ 20 tpi UNC is common in photography tripods
Bottomless microphone stand.
A rare type of microphone stand is the "bottomless" microphone stand—essentially a microphone stand with no base, so a singer must hold it throughout a live performance. It is useful as a mobile prop.
Freddie Mercury (the lead singer of Queen), discovered the device by accident: he grabbed a standard microphone stand with such force that it dislodged from its base. For the rest of his career he used a bottomless microphone stand regularly. Robbie Williams as well as heavy metal singers Joey Belladonna of Anthrax and Chuck Billy of Testament also use bottomless microphone stands.


Heptatonic scale

A heptatonic scale is a musical scale that has seven pitches (a.k.a. tones) per octave. Examples include the "major scale" or "minor scale"; e.g., in C major: C D E F G A B C—and in the relative minor, A minor, natural minor: A B C D E F G A; the "melodic minor scale", A B C D E FGA ascending, A G F E D C B A descending; the "harmonic minor scale", A B C D E F GA; and a scale variously known as the "Byzantine", and "Hungarian", scale, C D E F G A B C. Indian classical theory postulates seventy-two seven-tone scale types, collectively called "thaat", whereas others postulate twelve or ten (depending on the theorist) seven-tone scale types.
Several heptatonic scales in Western, Roman, Spanish, Hungarian, and Greek music can be analyzed as juxtapositions of tetrachords. All heptatonic scales have all intervals present in their interval vector analysis, and thus all heptatonic scales are both hemitonic and tritonic. There is a special affinity for heptatonic scales in the Western key signature system.
Diatonic scale.
A diatonic scale is any seven-note scale constructed sequentially using only whole tones and half tones, repeating at the octave, having a tonal center, and comprising only one tritone interval between any two scale members, which ensures that the half tone intervals are as far apart as possible. In Western music, there are seven such scales, and they are commonly known as the modes of the major scale (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian).
Melodic minor scale.
In traditional classical theory, the melodic minor scale has two forms, as noted above, an ascending form and a descending form. Although each of these forms of itself comprises seven pitches, together they comprise nine, which might seem to call into question the scale's status as a heptatonic scale. In certain twentieth-century music, however, it became common systematically to use the ascending form for both ascending and descending passages. Such a use has been notably ascribed to the works of Béla Bartók and to bop and post-bop jazz practice. The traditional descending form of the melodic minor scale is equivalent to the natural minor scale in both pitch collection (which is diatonic) and tonal center.
Harmonic minor scale.
The harmonic minor scale is so called because in tonal music of the common practice period (from approximately 1600 to approximately 1900) chords or harmonies are derived from it more than from the natural minor scale or the melodic minor scale. The augmented second between its sixth degree and its raised seventh degree (the "leading tone"), traditionally considered undesirable in melodic progression, is avoided by placing these pitches in different voices in adjacent chords, as in this progression: F A D, F G B, F A C (ii°b–V7d–iv in C minor). The A in the middle voice does not ascend to B, and the B in the upper voice does not descend to A.
Heptatonia prima and secunda.
The names "heptatonia prima" and "heptatonia secunda" apply to various seven-note scales that can be formed using tones and semitones, but without two semi-tones in succession. (Some are more theoretical.) They are:
Heptatonia prima.
Beginning on keynote C and working up the notes of the 'natural minor' scale (A, B, C, D, E, F, G, A), the seven modes are:
Heptatonia secunda.
While the diatonic modes have two and three tones between each semitone, the heptatonia secunda modes have one and four.
These are sometimes called modes of the melodic ascending minor since that is the most commonly used scale of this type, but other modes can be produced by starting on the different scale notes in turn.
Thus starting on keynote A as above and following the notes of the ascending melodic minor (A, B, C, D, E, F, G) yields these seven modes:
These modes are more awkward to use than those of the diatonic scales due to the four tones in a row yielding augmented intervals on one hand while the one tone between two semitones gives rise to diminished intervals on the other. For example, the last two modes listed above both have 'Locrian' diminished triads built on their tonics, giving them unstable tonality, while the third mode not only has an augmented fourth a la the Lydian mode but also an augmented fifth making the dominant and subdominant essentially unusable.
Heptatonia tertia.
The last group of seven-note tone/semitone scales is "heptatonia tertia", and consists of scales with two adjacent semitones—which amounts to a whole-tone scale, but with an additional note somewhere in its sequence, e.g., B C D E F G A. One such example is the Neapolitan major scale.
Other heptatonic scales.
If the interval of the augmented second is used, many other scales become possible. These include
Gypsy I-II-III-IV-V-VI-VII
Hungarian I-II-III-IV-V-VI-VII
The scales are symmetrical about the tonic and dominant respectively and the names are sometimes used interchangeably.
Phrygian major or dominant harmonic minor I-II-III-IV-V-VI-VII
This differs from the Phrygian in having a major third. It may also be considered built on the dominant of the harmonic minor scale.
Verdi's Scala Enigmatica I-II-III-IV-V-VI-VII i.e. G A B C D E F, which is similar to the heptonia tertia mentioned above, differing only in that the second degree here is flattened.
The harmonic major scale differs from the major scale by having a flat sixth degree: I-II-III-IV-V-VI-VII.
Melakarta.
Melakarta is a South Indian classical method of organizing Raagas based on their unique heptatonic scales. The postulated number of melakarta derives from arithmetical calculation and not from Carnatic practice, which uses far fewer scale forms. Seven-pitch melakarta are considered subsets of a twelve-pitch scale roughly analogous to the Western chromatic scale. The first and fifth melakarta tones, corresponding to the first and eighth chromatic tones, are invariable in inflection, and the fourth melakarta tone, corresponding to the sixth or seventh chromatic tone, is allowed one of two inflections only, a natural () position and a raised () position. The second and third melakarta tones can be picked from the 4 chromatic tones (second through fifth), and similarly for the sixth and seventh. Thus the number of possible forms is equal to twice the square of the number of ways a two-membered subset can be extracted from a four-membered set:
Thaat.
Hindustani heptatonic theory additionally stipulates that the second, third, sixth and seventh degrees of heptatonic scale forms ("septak") are also allowed only two inflections each, in this case, one natural position, and one lowered ("komal") position. Arithmetically this produces 25, or thirty-two, possibilities, but Hindustani theory, in contradistinction to Carnatic theory, excludes scale forms not commonly used.
Chinese Gongche notation.
Gongche notation heptatonic scale gives a do, re, mi, (between fa and fa), sol, la, (between ti and ti) heptatonic scale.


4037 Ikeya


Water detector

A water detector is an electronic device that is designed to detect the presence of water for purposes such as to provide an alert in time to allow the prevention of water leakage. A common design is a small cable or device that lies flat on a floor and relies on the electrical conductivity of water to decrease the resistance across two contacts. The device then sounds an audible alarm together with providing onward signalling in the presence of enough water to bridge the contacts. These are useful in a normally occupied area near any infrastructure that has the potential to leak water, such as HVAC, water pipes, drain pipes, vending machines, dehumidifiers, or water tanks.
Water leak detection.
Water leak detection is an expression more commonly used for larger, integrated systems installed in modern buildings or those containing valuable artifacts, materials or other critical assets where early notification of a potentially damaging leak would be beneficial. In particular, water leak detection has become a necessity in data centers, trading floors, banks, archives and other mission-critical infrastructure.
The water leak detection industry is small and specialized with only a few manufacturers operating worldwide. The original application was in the void created by "computer room" floors in the days of large main-frame computer systems. These use a modular, raised floor based around a structural "floor tile" usually 600 mm square and supported at the corners by pedestals. The void created gave easy access and routing for the mass of power, networking and other interconnecting cables associated with larger computer systems - processors, drives, routers etc. mainframe computers also generated large amounts of heat so a void under the floor could also be used as a plenum to distribute and diffuse chilled air around the computer room. The void therefore was likely to have chilled water pipes running through it along with the drains for condensates associated with refrigeration plant. In addition, designers found the floor void a very convenient place to route other wet services feeding bathrooms, radiators and other facilities.
A leak occurring within a floor void would therefore go unnoticed until the hydrostatic head of pressure meant that the water found its way through to floors below where its dripping through the ceiling would be noted or, and more disconcerting, the water would penetrate the joints and connectors of the power or network cabling and cause system failure from short circuit.
Current digital water leak detection systems can locate multiple water leaks to within 1 meter resolution over a complex network of cables running several kilometers. This functionality reduces the downtime and potential damage caused by inaccurate reporting that was common with older analogue based systems.
Water leak detection systems can be integrated with Building Management Systems using multiple protocols such as Modbus. Using SNMP protocols leak detection systems can inform IT staff in charge of monitoring data center and server rooms.
Integrated multi-zone systems.
The computer room therefore became the early application for systems which would alert the operator to a leaking pipe in sufficient time for remedial action to be taken to prevent a disaster.
As computer rooms could be quite large simple "point of use" detectors were not really appropriate although Point Sensors do have value where simple, single point detection is required in, say, basements and sumps. Most modern leak detection systems developed around the use of a water sensitive cable which can be laid in long lengths and complex patterns around the base of the floor; around the perimeter of rooms; as a "barrier" over which water has to flow; following, tracing or attached directly to lines of water pipes.
General application.
The mainframe computer room has largely been replaced with the Data Centre but the application has remained with almost universal use of "computer-room" style raised floors in nearly all new commercial and office construction. To warrant the installation of leak detection the operator has to perceive the risk in addition to the circumstances but most Mechanical and Electrical Design Engineers will take a view of the risk of damage from a leak in terms of effect on the client's own operations, services and assets and, often as important, those of their adjoining neighbours and those on floors below.
The installation of leak detection systems is therefore becoming more commonplace in most new commercial office construction schemes along with the more obvious targets of museums, galleries and archives.
Leak detection systems must be unobtrusive, effective and robust enough to withstand getting dirty and the moderate physical abuse of other works being carried out under the same floor.
Zoned systems have a reputation for being safe, reliable and not prone to the same types of false alarms which those systems which use cumulative resistance techniques.
Manufacturers such as TTK from France have introduced hi-tech variants like FG-NET touch screen panels with interactive maps on screen. The sensing cables are fitted with micro-controllers patented, that allows unique ability to pin-point faults on every individual sense cable simultaneously.
The leak detection industry is very small and it can be expected that manufacturers will also offer an installation and after sales service.


4737 Kiladze


2754 Efimov

2754 Efimov, provisionally named , is a stony asteroid and binary system from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 13 August 1966, by Russian astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula. The asteroid was named after Russian aviator Mikhail Efimov.
Orbit and classification.
"Efimov" orbits the Sun in the inner main-belt at a distance of 1.7–2.7 AU once every 3 years and 4 months (1,214 days). Its orbit has an eccentricity of 0.23 and an inclination of 6° with respect to the ecliptic.
Physical characteristics.
In the SMASS classification, "Efimov" is a Sa-type asteroid, which belong to the larger group of S-type asteroids. It is also characterized as a L-type asteroid by PanSTARRS photometric survey.
The "Collaborative Asteroid Lightcurve Link" assumes a standard albedo for stony asteroids of 0.20 and derives a diameter of 4.98 kilometers with an absolute magnitude of 13.92.
Satellite.
"Efimov" is a binary asteroid. In 2006, astronomers discovered a minor-planet moon, designated around "Efimov" using lightcurve observations, with a diameter of 1.29 kilometers and an orbital period of 14 hours and 46 minutes.
Naming.
This minor planet named in memory of Russian aviator Mikhail Nikiforovich Efimov (; 1881–1919), who was the first to realize steep turns and dives.
The approved naming citation was published by the Minor Planet Center on 31 May 1988 ().


3 nm process

In semiconductor manufacturing, the 3 nm process is the next die shrink after the 5-nanometre MOSFET (metal–oxide–semiconductor field-effect transistor) technology node. , Intel, Samsung, and TSMC have all announced plans to put a 3 nm semiconductor node into commercial production. Samsung's process is based on GAAFET (gate-all-around field-effect transistor) technology, a type of multi-gate MOSFET technology, while TSMC's 3nm process will still use FinFET (fin field-effect transistor) technology, despite TSMC developing GAAFET transistors. Specifically, Samsung plans to use its own variant of GAAFET called MBCFET (multi-bridge channel field-effect transistor).
The term "3 nanometer" has no relation to any actual physical feature (such as gate length, metal pitch or gate pitch) of the transistors. It is a commercial or marketing term used by the chip fabrication industry to refer to a new, improved generation of silicon semiconductor chips in terms of increased transistor density, increased speed and reduced power consumption. For example, TSMC has stated that its 3nm FinFET chips will reduce power consumption by 25 to 30 percent at the same speed, increase speed by 10 to 15 percent at the same amount power and increase transistor density by about 33 percent compared to its previous 5nm FinFET chips.
History.
Research and technology demos.
In 1985, a Nippon Telegraph and Telephone (NTT) research team fabricated a MOSFET (NMOS) device with a channel length of 150 nm and gate oxide thickness of 2.5 nm. In 1998, an Advanced Micro Devices (AMD) research team fabricated a MOSFET (NMOS) device with a channel length of 50 nm and oxide thickness of 1.3 nm.
In 2003, a research team at NEC fabricated the first MOSFETs with a channel length of 3 nm, using the PMOS and NMOS processes. In 2006, a team from the Korea Advanced Institute of Science and Technology (KAIST) and the National Nano Fab Center, developed a 3 nm width multi-gate MOSFET, the world's smallest nanoelectronic device, based on gate-all-around (GAAFET) technology.
Commercialization history.
In late 2016, TSMC announced plans to construct a 5 nm–3 nm node semiconductor fabrication plant with a co-commitment investment of around US$15.7 billion.
In 2017, TSMC announced it was to begin construction of the 3 nm semiconductor fabrication plant at the Tainan Science Park in Taiwan. TSMC plans to start volume production of the 3 nm process node in 2023.
In early 2018, IMEC and Cadence stated they had taped out 3 nm test chips, using extreme ultraviolet lithography (EUV) and 193 nm immersion lithography.
In early 2019, Samsung presented plans to manufacture 3 nm GAAFET (gate-all-around field-effect transistors) at the 3 nm node in 2021, using its own MBCFET transistor structure that uses nanosheets instead of nanowires; delivering a 35% performance increase, 50% power reduction and a 45% reduction in area when compared with 7nm. Samsung's semiconductor roadmap also included products at 8, 7, 6, 5, and 4 nm 'nodes'.
In December 2019, Intel announced plans for 3 nm production in 2025.
In January 2020, Samsung announced the production of the world's first 3 nm GAAFET process prototype, and said that it is targeting mass production in 2021.
In August 2020, TSMC announced details of its N3 3 nm process, which is new rather than being an improvement over its N5 5 nm process. Compared with the N5 process, the N3 process should offer a 10–15% (1.10–1.15×) increase in performance, or a 25–35% (1.25–1.35×) decrease in power consumption, with a 1.7× increase in logic density (a scaling factor of 0.58), a 20% increase (0.8 scaling factor) in SRAM cell density, and a 10% increase in analog circuitry density. Since many designs include considerably more SRAM than logic, (a common ratio being 70% SRAM to 30% logic) die shrinks are expected to only be of around 26%. TSMC plans risk production in 2021 with volume production in the second half of 2022.
Beyond 3 nm.
The ITRS uses (as of 2017) the terms "2.1 nm", "1.5 nm", and "1.0 nm" as generic terms for the nodes after 3 nm. "2-nanometre" (2 nm) and "14 angstrom" (14 Å or 1.4 nm) nodes have also been (in 2017) tentatively identified by An Steegen (of IMEC) as future production nodes after 3 nm, with hypothesized introduction dates of around 2024, and beyond 2025 respectively.
In late 2018, TSMC chairman Mark Liu predicted chip scaling would continue to 3 nm and 2 nm nodes; however, as of 2019, other semiconductor specialists were undecided as to whether nodes beyond 3 nm could become viable. TSMC began research on 2 nm in 2019. It has been reported that TSMC is expected to enter 2 nm risk production around 2023 or 2024.
In December 2019, Intel announced plans for 1.4 nm production in 2029.
In May 2021 IBM announced it had produced 2 nm chipmaking technology at their manufacturing research center in Albany and had successfully made a prototype "fingernail-sized" chip with upwards of 50 billion transistors,
which translates to 333 million transistors per square millimeter (assuming a chip area of 150 square millimeters as communicated by IBM). By comparison, TSMC's 3nm chips would contain around 291 million transistors per square millimeter.