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B. L. Turner
B is the second letter of the Latin alphabet. B may also refer to: Science, technology, and mathematics Astronomy * Astronomical objects in the List of dark nebulae#Barnard objects, Barnard list of dark nebulae (abbreviation B) * Latitude (''b'') in the galactic coordinate system Biology and medicine * Haplogroup B (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup * Haplogroup B (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup * blood type, Blood type B * ATC code B ''Blood and blood forming organs'', a section of the Anatomical Therapeutic Chemical Classification System * Vitamin B * Hepatitis B * Berlin Botanical Garden and Botanical Museum, assigned the abbreviation B as a repository of herbarium specimens Computing * B (programming language) * B-Method, for computer software development * B-tree, a data structure * Bit (b) * Byte (B) * , an HTML element#b, HTML element denoting bold text Physical and chemical quantities and units * One of the reciprocal lattice vectors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Dark Nebulae
This is a list of dark nebulae (absorption nebulae), also called "dark clouds". List *E Nebula ( Barnard 142 and 143) *Barnard 68, possibly the closest to Earth at about 400 light-years. *Bernes 157 (Sandqvist and Lindroos, SL 39-41), another close dark nebula of the Corona Australis Molecular Cloud, which includes NGC 6729 Named absorption nebulae See also the references to names from other cultures at dark cloud constellations: *Coalsack Nebula *Cone Nebula *Dark Doodad Nebula * Dark Horse Nebula *Horsehead Nebula ( Barnard 33) *Pipe Nebula (also see Dark Horse Nebula; includes Barnard 59, 77 and 78) * Snake Nebula (also see Dark Horse Nebula) * Keyhole Nebula Barnard objects See also *Lists of astronomical objects *Nebula *Dark nebulae * Bok globules External linksEast Valley Astronomical Society Barnard Dark Nebulae Observing Program [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molality
Molality is a measure of the number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent. This contrasts with the definition of molarity which is based on a specified volume of solution. A commonly used unit for molality in chemistry is Mole (unit), mol/kilogram, kg. A solution of concentration 1 mol/kg is also sometimes denoted as ''1 molal''. The unit ''mol/kg'' requires that molar mass be expressed in ''kg/mol'', instead of the usual ''g/mol'' or ''kg/kmol''. Definition The molality (''b''), of a Solution (chemistry), solution is defined as the amount of substance (in mole (unit), moles) of solute, ''n''solute, divided by the mass (in kg) of the solvent, ''m''solvent: :b = \frac In the case of solutions with more than one solvent, molality can be defined for the mixed solvent considered as a pure pseudo-solvent. Instead of mole solute per kilogram solvent as in the binary case, units are defined as mole solute per kilogram mixed solvent. Ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B Horizon
A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. 'coarser' or 'sandier' than the horizons above and below. The identified horizons are indicated with symbols, which are mostly used in a hierarchical way. Master horizons (main horizons) are indicated by capital letters. Suffixes, in form of lowercase letters and figures, further differentiate the master horizons. There are many different systems of horizon symbols in the world. No one system is more correct—as artificial constructs, their utility lies in their ability to accurately describe local conditions in a consistent manner. Due to the different definitions of the horizon symb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (vacuum Tube)
A generic triode vacuum tube circuit showing "A", "B" and "C" batteries">vacuum_tube.html" ;"title="triode vacuum tube">triode vacuum tube circuit showing "A", "B" and "C" batteries In the early days of electronics, vacuum tube (called ''valves'' in British contexts) devices (such as radios) were powered by battery (electricity), batteries. Each battery had a different designation depending on which tube element it was associated with. Initially, the only such device was a diode with only a filament (cathode) and a plate (anode). Following the direction of electron flow, these electrodes were identified as "A" and "B", respectively and thus the associated batteries were referred to as the "A" and "B" batteries respectively. Later, when the control grid element was added to create the triode tube, it was logically assigned the letter "C" and supplied from a "C" battery. Subsequent addition of further internal elements to improve the performance of the triode did not require an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulb (photography)
The Bulb setting (abbreviated B) on camera shutters is a momentary-action mode that holds shutters open for as long as a photographer depresses the shutter-release button. The Bulb setting is distinct from shutter's Time (T) setting, which is an alternate-action mode where the shutter opens when the shutter-release button is pressed and released once, and closes when the button is actuated again. History Decades before the first flashbulbs, some box cameras and many view cameras and folding cameras came with a detachable pneumatic shutter release with a rubber bulb on the end; "Bulb" refers to the rubber shutter release bulb. Though mechanically timed exposures could also be triggered by squeezing the shutter release bulb, "Bulb" exposures then had the same momentary action as camera shutters have today, as per this description from Sears Roebuck's 1909 ''Cameras Photographic Supplies'': Around 1894 in Germany, the momentary-action setting on camera shutters made by C. A. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral borax, sodium borate, and the ultra-hard crystals of boron carbide and boron nitride. Boron is synthesized entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, so it is a low-abundance element in the Solar System and in the Crust (geology), Earth's crust. It constitutes about 0.001 percent by weight of Earth's crust. It is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known deposits are in Turkey, the largest producer of boron minerals. Elemental b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boolean Domain
In mathematics and abstract algebra, a Boolean domain is a set consisting of exactly two elements whose interpretations include ''false'' and ''true''. In logic, mathematics and theoretical computer science, a Boolean domain is usually written as , or \mathbb. The algebraic structure that naturally builds on a Boolean domain is the Boolean algebra with two elements. The initial object in the category of bounded lattices is a Boolean domain. In computer science, a Boolean variable is a variable that takes values in some Boolean domain. Some programming languages feature reserved words or symbols for the elements of the Boolean domain, for example false and true. However, many programming languages do not have a Boolean datatype in the strict sense. In C or BASIC, for example, falsity is represented by the number 0 and truth is represented by the number 1 or −1, and all variables that can take these values can also take any other numerical values. Generalizations The Boole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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