Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

Expand All
Entries
Topic Review
Mongol Conquest of Khwarezmia
The Mongol conquest of Khwarezmia (Persian: حمله مغول به خوارزم‎), or the Mongol invasion of Iran (Persia) (Persian: حمله مغول به ایران‎), from 1219 to 1221 marked the beginning of the Mongol conquest of the Islamic states. The Mongol expansion would ultimately culminate in the conquest of virtually all of Asia as well as parts of Eastern Europe, with the exception of Japan , the Mamluk Sultanate of Egypt, Siberia, and most of the Indian subcontinent and Southeast Asia. According to the Persian historian Minhaj-i-Siraj, Genghis Khan sent the ruler of the Khwarazmian Empire, Muhammad II, a message seeking trade and greeted him as his neighbor: "I am master of the lands of the rising sun while you rule those of the setting sun. Let us conclude a firm treaty of friendship and peace", or he said "I am Khan of the lands of the rising sun while you are sultan of those of the setting sun: Let us conclude a firm agreement of friendship and peace." The Mongols' original unification of all "people in felt tents", unifying the nomadic tribes in Mongolia and then the Turkomans and other nomadic peoples, had come with relatively little bloodshed, and almost no material loss. The Mongol wars with the Jurchens was known to Muhammad II and he agreed to this peace treaty. War between the Mongols and the Khwarazmian Empire started less than a year later, when a Mongol caravan and its envoys were massacred in the Khwarazmian city of Otrar. In the ensuing war, lasting less than two years, the Khwarazmian dynasty was destroyed and the Khwarazmian Empire was conquered.
  • 37.0K
  • 16 Nov 2022
Biography
Mary Eleanor Spear
Mary Eleanor Hunt Spear (March 4, 1897 – January 22, 1986) was an American data visualization specialist, graphic analyst and author, who pioneered development of the bar chart and box plot. Spear was born in Jonesboro, Indiana, the daughter of Amos Zophar Hunt and Mabel Elizabeth Ewry Hunt.[1] She attended Peabody Elementary School, Washington D.C.,[2] followed by Eastern High School.[2] S
  • 1.4K
  • 16 Nov 2022
Topic Review
Meunier Rifle
The Meunier rifle, known as the "Meunier A6" or "STA No. 8", evolved as a part of the program initiated in 1890 by the French military to develop a semi-automatic infantry rifle that would eventually replace the Mle 1886-93 Lebel rifle. Four government research establishments (STA, ENT, Puteaux and CTV) proposed over 20 prototypes. About half of them were based on recoil (both short recoil and long recoil) and the others were gas operated. This secret program was placed under the direction of General Naquet-Laroque who headed the Puteaux (APX) government arsenal.
  • 975
  • 16 Nov 2022
Biography
Andrew Dickson White
Andrew Dickson White (November 7, 1832 – November 4, 1918) was an American historian and educator, who was the cofounder of Cornell University and served as its first president for nearly two decades. He was known for expanding the scope of college curricula.[1] A politician, he had served as state senator in New York. He was later appointed as a US diplomat to Germany and Russia, among other
  • 8.0K
  • 16 Nov 2022
Topic Review
Recovery Point Objective
A recovery point objective (RPO) is defined by business continuity planning. It is the maximum targeted period in which data might be lost from an IT service due to a major incident. The RPO gives systems designers a limit to work to. For instance, if the RPO is set to four hours, then in practice, off-site mirrored backups must be continuously maintained – a daily off-site backup on tape will not suffice.
  • 847
  • 16 Nov 2022
Topic Review
Four-day Week
A four-day week, or a compressed work schedule, is an arrangement where a workplace or school has its employees or students work or attend school over the course of four days per week rather than the more customary five. This arrangement can be a part of flexible working hours, and is sometimes used to cut costs, as seen in the example of the so-called "4/10 work week," where employees work a normal 40 hours across four days, i.e. a "four-ten" week. However, a four-day week can also be a fixed work schedule. More modest attempts to enact a 32-hour workweek (a four-day week and an eight-hour day combined) have remained elusive in the following 80 years despite pockets of residual support.
  • 1.4K
  • 16 Nov 2022
Topic Review
Node
A node is a point along a standing wave where the wave has minimum amplitude. For instance, in a vibrating guitar string, the ends of the string are nodes. By changing the position of the end node through frets, the guitarist changes the effective length of the vibrating string and thereby the note played. The opposite of a node is an anti-node, a point where the amplitude of the standing wave is at maximum. These occur midway between the nodes.
  • 1.4K
  • 16 Nov 2022
Topic Review
Gas Chromatography - Vacuum Ultraviolet Spectroscopy (GC-VUV)
Gas Chromatography - Vacuum Ultraviolet (GC-VUV) spectroscopy is a universal detection platform for gas chromatography. The first benchtop detector was introduced in 2014 with detection capabilities between 120 - 240 nm. This portion of the ultraviolet spectrum had historically been restricted to bright source synchrotron facilities due to significant background absorption challenges inherent to working within the wavelength range. Further detector platform development has extended the wavelength detection range out from 120 - 430 nm. VUV detection provides both qualitative and quantitative spectral information for most gas phase compounds. GC-VUV spectral data is three dimensional (time, absorbance, wavelength) and specific to chemical structure. Nearly all compounds absorb in the VUV region of the electromagnetic spectrum with the exception of carrier gases hydrogen, helium, and argon. The high energy, short wavelength VUV photons probe electronic transitions in almost all chemical bonds including ground state to excited state. The result is spectral "fingerprints" that are specific to individual compound structure and can be readily identified by the VUV library. Unique VUV spectra enable closely related compounds such as structural isomers to be clearly differentiated. VUV detectors complement mass spectrometry, which struggles with characterizing constitutional isomers and compounds with low mass quantitation ions. VUV spectra can also be used to deconvolve analyte co-elution, resulting in an accurate quantitative representation of individual analyte contribution to the original response. This characteristically lends itself to significantly reducing GC runtimes through flow rate-enhanced chromatographic compression. VUV spectroscopy follows the simple linear relationship between absorbance and concentration described by the Beer-Lambert Law resulting in more accurate retention time-based identification. VUV absorbance spectra also exhibit feature similarity within compound classes, meaning VUV detectors can rapidly compound class characterization in complex samples through compound spectral shape and retention index information. Advances in technology reduces the typical group analysis data processing time from 15-30 minutes to <1 minute per sample.
  • 3.3K
  • 17 Nov 2022
Topic Review
Pressure-Volume Loop Experiments
Pressure Volume loops are widely used in basic and preclinical research. Left ventricular PV loops are considered to be the gold standard for hemodynamic assessment and are widely used in research to evaluate cardiac performance. While it has long been possible to measure pressure in real time from the left ventricle, measuring the volume was technically more difficult. The use of ultrasonic sonomicrometry and the development of the conductance catheter triggered renewed interest in PV loops studies. In sonomicrometry, small ultrasonic transducers (usually referred to as "crystals") transmit signals to each other, and the distance between them is accurately determined based on the transit-time of the signals. By knowing the long and short axis lengths of the ventricle, ventricular volume is easily and accurately determined. Conductance cathethers measure instantaneous conductance in the left ventricle, which is then converted to blood volume using complex formulas and usually after determining and applying various correction factors. Typically only one method is used to perform PV studies in research settings. The miniaturization of sonomicrometer crystals and pressure catheters have made mice PV loop studies feasible and more common.
  • 730
  • 16 Nov 2022
Topic Review
Outline of Heresies in the Catholic Church
The following outline is provided as an overview of and topical guide to heresies (as regarded by the Roman Catholic Church): Heresy, in Catholicism, is defined as belief that conflicts with established Catholic dogma.
  • 15.1K
  • 16 Nov 2022
  • Page
  • of
  • 863

Other Entry Collections

>>