The Foot can refer to List of Six Feet Under episodes Season 1 2001 An episode of the first season of Six Feet Under TV series Six Feet Under . The Foot Clan of Teenage Mutant Ninja Turtles . The Foot Book The Foot of Cupid The Foot can refer to the 4 Grey Goose Bottles that are blocked on a back bar. The Foot. Band See also Foot in anatomy Foot disambiguation disambig ... more details
s footlength was 26.3 cm with a standard deviation of 1.2 cm. ref cite journal author Hawes MR, Sovak D title Quantitative morphology of the human foot in a North American population journal ...Other uses about human anamtical structure the measure unit Foot unit Mergefrom Foot type date August 2009 pp move indef pp semi indef Infobox Anatomy Image Male Right Foot 1.jpg Name Foot Latin pes GraySubject ... fibular nerve superficial fibular Lymph MeshName Foot MeshNumber A01.378.610.250 Dorlands three 000041532 DorlandsID Foot The foot plural feet is an anatomical structure found in many vertebrates ... animals with feet, the foot is a separate organ at the terminal part of the leg made up of one ... s or similar footwear covering material for protection from hazards when walking outside. Foot fetishism is the most common form of sexual fetish. ref http abcnews.go.com Health rex ryans foot video not necessarily unhealthy story?id 12467617 ref ref http www.chaimedia.com list 197.html ref Human foot Anatomy The human foot and ankle is a strong and complex mechanical structure containing more than ..., and ligaments. ref name Podiatry Channel Podiatry Channel, Anatomy of the foot and ankle ref An anthropometric ... url ref The foot can be subdivided into the hindfoot, the midfoot, and the forefoot The hindfoot ... . Connected to the talus at the subtalar joint , the calcaneus, the largest bone of the foot ... bones, form the arches of the foot which serves as a shock absorber. The midfoot is connected to the hind and fore foot by muscles and the plantar fascia . ref name Podiatry Channel The forefoot is composed ... are called interphalangeal articulations of foot interphalangeal and those between the metatarsus ... part of the top of the foot between the toes and the ankle. Skeleton File foot.png thumb A human foot label three is the instep. tibia , fibula Tarsus skeleton tarsus Talus bone talus , calcaneus ... bone fourth , and fifth metatarsal bone Phalanges of the foot phalanges There can be many sesamoid ... more details
Orphan date February 2009 infobox television show name On Foot format Travel show image Image onfootlogo.JPG 250px picture format 480i SDTV runtime 3 times a day creator Tim Tayag developer Burger Bacon Production director Tim Tayag , Allan Manalo , Theodore Gonzalves executive producer Tim tayag, Katrina Holigores, Leo Udtohan starring Tim Tayag country Philippines network Living Asia Channel LAC first aired September 2001 last aired present num episodes 20 website http livingasiachannel.net onfoot index.html preceded by followed by related imdb id On Foot Travel show is a travel show on the Living Asia Channel . The show follows the comic and upbeat television host Tim Tayag around the Philippine and Asian countries. The program is a co production of Bacon Burger Productions and CCI Asia Group Corporation and is being aired in the Philippines via The Living Asia Channel. It is also being aired simultaneously in North America via The Filipino Channel Direct, North America and Canada via Globecast World TV In Asia, we can be seen in Singapore, Malaysia, Vietnam and Laos as well via The Mabuhay Satellite Corporation. In the Philippines, The Living Asia Channel is currently aired on major cable networks such as Home, Dream, Destiny and Sky. On Foot is everyday three times a day on an eight hour loop seen simultaneously in the other countries with broadcast partners. Objectives According to Tayag s official website, ref www.timtayag.com ref On Foot is aimed at young independent travelers a sort of streetwise cookbook for traveling alone. When you travel on foot and interact with the locals, you penetrate the veneer of the guidebooks and maps and mine the grit of real life. Self ... of traveling in the Philippines and other Asian countries. On Foot is an indispensable resource ... and Siquijor, Tayag in an interview said, Bohol is the best episode so far on On Foot. Episodes Quiapo ... Tagaytay 2008 Off the Wall 1 2007 One Foot in Iloilo 2007 One Foot on Iloilo 2 2007 Palawan 2007 ... more details
Orphan date February 2009 Refimprove date April 2007 Short of a length sometimes referred to as back of a length or short of a good length is a term used in the sport of cricket . It describes a delivery from the Bowler cricket bowler that pitches short of the optimum length. Length in cricket defines where the ball pitches on the wicket. ref http content www.cricinfo.com ci content story 239756.html A glossary of cricket terms & 124 Cricket News & 124 Global & 124 ESPN Cricinfo ref A good length ball is one that pitches at a distance that makes it difficult for the batsman to ascertain whether to play the ball on the front foot or back foot. A bouncer is a ball that passes the batsman above chest height. A short of a length delivery is one that pitches in the area between the bouncer and good length balls. This delivery can be dangerous for a batsman as it can bounce higher into the midriff. Also, the delivery can be extremely useful to a seam bowling seam bowler . Good exponents include Stephen Harmison and Glenn McGrath . References Reflist See also http en.wikipedia.org wiki List of cricket terms Category Cricket captaincy and tactics Category Cricket deliveries Category Cricket terminology cricket term stub ... more details
Unreferenced date September 2009 TOC right Many different units of length have been used across the world. The main units in modern use are U.S. customary units in the United States and the Metric system elsewhere. British Imperial unit s are still used for some purposes in the United Kingdom and some other countries. The metric system is sub divided into International System of Units SI and non SI units. Metric system main Metric system SI units main International System of Units Common units of length in the International System of Units SI are metre and its multiples, such as centimetre or kilometre Non SI units Non SI units of length include fermi fm 1 femtometre in SI units angstrom 100 picometre s in SI units micron 1 micrometre in SI units Norwegian Swedish mil 10,000 metres Imperial US units main Imperial unit main U.S. customary units Common Imperial units and U.S. customary units of length include inch 2.54 cm mil one thousandth of an inch, one thou unit of length thou footlengthfoot 12 inches, 0.3048 m yard 3 ft, 0.9144 m terrestrial mile 5280 ft, 1609.344 m Marine In addition, the following are used by mariners fathom for depth only in non metric ... Archaic units of distance include cana unit of length cana cubit Rope unit Rope league unit league Li unit li China Pace unit of length pace the double pace of about 5 feet used in Ancient Rome ... are Double decker bus 9.5 10.9 metres in length Football field generally around 110 metres, depending ... unit of length created as part of an Massachusetts Institute of Technology MIT fraternity prank Other Horse racing and other equestrian activities keeps alive furlong convert 0.125 mi m length horse racing horse length convert 8 ft m Physics also uses Planck length Bohr radius See also Systems of measurement Medieval weights and measures English unit Orders of magnitude length systems of measurement Astronomy length Category Units of length ar be x old ... more details
Unreferenced date December 2009 Line and length in cricket refers to the direction and point of bouncing on the pitch cricket pitch of a delivery cricket delivery . The two concepts are frequently discussed together. Ahsan The line of a cricket delivery is the direction of its trajectory measured in the Horizontal plane horizontal axis. More simply, it is a measure of how far to the left or right the ball is travelling, compared to a line drawn straight down the pitch. It is usually referred to in terms of the directions Fielding cricket Off and leg side fields off away in front of the batsman and leg side leg in towards or behind the batsman , rather than left and right, however. Line controls how much room the batsman has to play various shots, and sometimes dictates what shot he must play ... since been outlawed. See Bodyline for full details. Length File Length cricket .svg thumb right 325px A diagram showing the relative positions of short, good and full lengths The length of a delivery ... bouncing closer to the bowler , long or full bouncing nearer the batsman , or a good length an optimal length, somewhere in between . The length of a ball controls how high the ball rises from the pitch ... horizontally in its flight, also making it easier for the batsman to hit. A good length ball is a compromise ..., but not so far that he can react easily to hit it. For quick bowlers the good length ball ... at about three to four metres before the batsman. Though the optimal length will vary according to the state .... A bowler can use variation in length to upset the rhythm of a batsman. A typical sequence would be a series ... foot, to allow him more time to hit the ball, followed by a full ball bouncing near the batsman s legs. If the batsman does not react to the change in length quickly enough, he can be left with his weight on the back foot and, if he misses the ball with his bat, in danger of being out either bowled ... And Length Category Bowling cricket ... more details
Sentence length may refer to In linguistics, the length of a Sentence linguistics In penology, the length of a Sentence law In music, the length of a Sentence music dab ... more details
wiktionarypar LengthLength in its basic meaning is the long dimension of an object. Length may also refer to Length measurement Length phonetics , in phonetics Vowel length Geminate consonant Arc lengthLength of a module , in abstract algebra Length of a polynomial Vector field length in vector calculus Line and length in cricket Horse length in equestrianism Nautical term Length overall disambig als L nge az Uzunluq d qiql dirm be x old ca Longitud desambiguaci de L nge es Longitud desambiguaci n nl Lengte nds L ng pl D ugo sv L ngd olika betydelser ... more details
orphan date December 2009 Scantling Length is a distance slightly less than the waterline length of a ship, and generally less than the overall length of a ship. In the American Bureau of Shipping ABS Rules for Building and Classing Steel Vessels, it is defined as the distance on the Waterline summer load line from the fore side of the stem to the centerline of the rudder stock. Scantling length need not be less than 96 , nor more than 97 of the length of the summer load line. Most other Classification society classification societies use a similar definition of scantling length to define the general length of a ship . The scantling length is used by classification society classification societies for all calculations where the waterline length, overall length, displacement fluid displacement length, etc is called for. Naval architects wishing to comply with class rules would also use the scantling length. References http www.eagle.org absdownloads downloads senddownload.cfm?id 443 ABS Rules for Building and Classing Steel Vessels, Part 3, Hull Construction and Equipment, Rule 3.1.1 3.1, 2007. Category Naval architecture ... more details
disambig Length scale , or scale length a significant concept in physics used to define the order of magnitude of a system Scale height , or scale length a specific parameter in physics denoting the distance over which a quantity decreases by a factor of e Scale string instruments a measurement of the length of a musical instrument string ... more details
In abstract algebra , the length of a module mathematics module is a measure of the module s size . It is defined to be the length of the longest chain of submodule s and is a generalization of the concept of dimension linear algebra dimension for vector space s. Modules with finite length share many important properties with finite dimensional vector spaces. Other concepts used to count in ring and module ... to define. There are also various ideas of dimension that are useful. Finite length commutative ... math N 0 subsetneq N 1 subsetneq cdots subsetneq N n math we say that n is the length of the chain. The length of M is defined to be the largest length of any of its chains. If no such largest length exists, we say that M has infinite length. A ring R is said to have finite length as a ring if it has finite length as left R module. Examples The zero module is the only one with length 0. Modules with length 1 are precisely the simple module s. For every finite dimensional vector space viewed as a module over the base field mathematics field , the length and the dimension coincide. The length ... M has finite length if and only if it is both Artinian module Artinian and Noetherian module Noetherian . If M has finite length and N is a submodule of M , then N has finite length as well, and we have length N length M . Furthermore, if N is a proper submodule of M i.e. if it is unequal to M , then length N length M . If the modules M sub 1 sub and M sub 2 sub have finite length, then so does their direct sum of modules direct sum , and the length of the direct sum equals the sum of the lengths ... sequence of R modules. Then M has finite length if and only if L and N have finite length, and we have length M length L length N . This statement implies the two previous ones. A composition series ... such that math N i 1 N i mbox is simple for i 0, dots,n 1 math Every finite length module M has a composition series, and the length of every such composition series is equal to the length of M . References ... more details
infobox IPA above IPA vowel length ipa symbol span style color silver a span & x02D0 span style color ... length is the perceived length phonetics duration of a vowel sound. Often the chroneme , or the longness ... not distinctive in most dialects of English language English , vowel length is an important phonemic ... thing Finnish phonology Length Finnish , Fijian language Phonology Fijian , Japanese phonology Vowels ... spoken variant s of Chinese languages Chinese . Many languages do not distinguish vowel length, and those ... vowels, e.g. Japanese h phoenix or Estonian j r ice edge . Vowel length and related features Stress linguistics Stress is often reinforced by allophonic vowel length, especially when it is lexical ... Finnish , a language with two phonemic lengths, indicates the stress by adding allophonic length ... vowel length, there are some where it may only occur in stressed syllables, e.g. in the Alemannic ... or Latin Classical Latin , vowel length is distinctive in unstressed syllables as well. In some languages, vowel length is sometimes better analyzed as a sequence of two identical vowels. In Finnic ... . Phonemic vowel length Many languages make a Phoneme phonemic distinction between long and short vowels ... and are still choosing . Short and long vowels in English Vowel length i.e., long and short , when ... English are those vowels written with the help of a silent e. Allophonic vowel length In certain ... extent, General American , there is allophone allophonic vowel length vowel phonemes are realized .... The short vowels are IPA as in kit , IPA as in foot , IPA as in dress , IPA ... of length is indeed present, there are also differences in the vowel quality quality tense phonetics ... than the former. Contrastive vowel length In Australian English phonology Australian English , there is contrastive vowel length in closed syllables between long and short IPA e and sometimes IPA . The following can be minimal pair s of length for many speakers style margin left 1em cellspacing ... more details
Contour length is a term used in molecular physics . The contour length of a polymer chain a big molecule consisting of many similar smaller molecules is its length at maximum physically possible Extension metaphysics extension . ref http iupac.org goldbook C01308.pdf Contour length in polymers http www.iupac.org publications compendium index.html IUPAC Compendium of Chemical Terminology , 2nd Edition, 1997 ref References small references small Category Polymer physics ... more details
Context date September 2010 A characteristic length is an important dimension that defines the scale of a physical system. Often such a length is used as an input to a formula in order to predict some characteristics of the system. Examples Reynolds number Biot number Nusselt number External links http www.answers.com topic characteristic length Definition physics stub DEFAULTSORT Characteristic Length Category Physical constants de Charakteristische L nge nl Hydraulische diameter pt Comprimento caracter stico ... more details
Unreferenced stub auto yes date December 2009 In physics , length scale is a particular length or distance determined with the precision of one order or a few orders of magnitude. The concept of length scale is particularly important because physical phenomena of different length scales cannot affect each other and are said to decouple. The decoupling of different length scales makes it possible to have a self consistent theory that only describes the relevant length scales for a given problem. Scientific reductionism says that the physical laws on the shortest length scales can be used to derive the effective description at larger length scales. The idea that one can derive descriptions of physics at different length scales from one another can be quantified with the renormalization group . In quantum mechanics the length scale of a given phenomenon is related to its de Broglie wavelength ... that is being probed. In relativistic mechanics time and length scales are related by the speed of light . In relativistic quantum mechanics or relativistic quantum field theory , length scales .... Often in high energy physics natural units are used where length, time, energy and momentum scales are described in the same units usually with units of energy such as GeV . Length scales are usually ... units of length squared and is measured in barn unit barn s. The cross section of a given process is usually the square of the length scale. Examples The atomic length scale is math ell a sim 10 10 ... ell a sim 1 alpha m e math . The length scale for the strong interaction s or the one derived from ... are roughly comparable. This length scale is determined by the range of the Yukawa potential . The lifetimes of strongly interacting particles, such as the rho meson , are given by this length scale ... are several times the associated energy scale 500 MeV to 3000 MeV . The electroweak length scale is shorter ... which is roughly 100 GeV. This length scale would be the distance where a Yukawa force is mediated ... more details
In fluid mechanics , capillary length is a characteristic length scale for fluid subject to a body force from gravity and a surface force due to surface tension . The capillary length is defined as ref name Batchelor G.K. Batchelor, An Introduction To Fluid Dynamics , Cambridge University Press 1967 ref math lambda c sqrt frac gamma rho g math , where math g math is the acceleration due to gravity and math rho math is the density of the fluid, and math gamma math is the surface tension of the fluid fluid interface. For clean water at standard temperature and pressure, the capillary length is 2mm. A capillary surface that has a characteristic length smaller than the capillary length can be considered a low Bond number surface. A sessile drop whose largest dimension is smaller than the capillary length, for example, will take the shape of spherical cap , which is the solution to the Young Laplace equation with gravity completely absent. See also Surface tension Young Laplace equation Capillarity References references fluiddynamics stub Category Fluid dynamics fr Longueur capillaire no Kapillarlengde ... more details
Unreferenced stub auto yes date December 2009 Length of stay LOS is a term commonly used to measure the duration of a single episode of hospitalization. Inpatient days are calculated by subtracting day of admission from day of wikt discharge discharge . However, persons entering and leaving a hospital on the same day have a length of stay of one. See hospital Terminology hospital . A popular statistic associated with length of stay is the average length of stay ALOS , calculated by dividing the sum of inpatient days by the number of patients admissions with the same Diagnosis related group DRG classification. A variation in the calculation of ALOS could be consider only length of stay during the period under analysis. The prospective payment system in U.S. Medicare United States Payment for services Medicare for reimbursing hospital care promotes shorter LOS by paying the same amount for procedures, regardless of days spent in the hospital. DEFAULTSORT Length Of Stay Category Medical terms Med stub de Verweildauer ... more details
Refimprove date January 2008 unit of length name Planck length m 0.00000000000000000000000000000000001616199 accuracy 5 Number of significant figures In physics , the Planck length , denoted sub P sub , is a unit of length , equal to val 1.616199 97 e 35 u metre s . It is a Fundamental unit base unit in the system of Planck units . The Planck length can be defined from three fundamental physical ... The Planck length math ell P math is defined as math ell P sqrt frac hbar G c 3 approx 1.616 199 97 ... Length ref ref NIST , http physics.nist.gov cgi bin cuu Value?plkl Planck length , http physics.nist.gov cuu Constants index.html NIST s published CODATA constants ref The Planck length is about 10 sup 20 sup of the diameter of a proton , and thus is an extremely small length. Measurements of electron ......22..102D ref which is a value still 10 sup 15 sup larger than Planck length. The Planck length ... significance of the Planck length is a topic of research. Because the Planck length is so many ... this length scale directly. Research on the Planck length is therefore mostly theoretical. In some forms of quantum gravity, the Planck length is the length scale at which the structure of spacetime ... between two locations less than one Planck length apart. The precise effects of quantum gravity are unknown ... at Planck length scale. The Planck area, equal to the square of the Planck length, plays a role in black .... In this case the Planck length would have no fundamental physical significance, and quantum gravitational effects would appear at other scales. In string theory , the Planck length is the order ... area value. In doubly special relativity , the Planck length is observer invariant. According to the generalized uncertainty principle, the Planck length is, within a factor of order unity, the shortest measurable length. The search of the laws of physics valid at the Planck length are a part of the search ... Orders of magnitude length Planck energy Planck epoch Planck scale Planck time Planck unit Max Planck ... more details
Reciprocal length or inverse length is a measurement used in several branches of science and mathematics . As the reciprocal of length , common units used for this measurement include the reciprocal metre or inverse metre m sup &minus 1 sup , the reciprocal centimetre or inverse centimetre cm sup &minus 1 sup , and, in optics , the dioptre . Quantities measured in reciprocal length include absorption coefficient or attenuation coefficient , in materials science curvature of a curve line , in mathematics gain , in laser physics magnitude vector magnitude of vector mathematics and physics vector s in reciprocal space , in crystallography more generally any spatial frequency e.g. in cycles per unit length optical power of a lens optics lens , in optics rotational constant of a rigid rotor , in quantum mechanics wavenumber , or magnitude of a wavevector , in spectroscopy Further reading Cite paper title A two parameter perturbation series for the reciprocal length of polymer chains and subchains lastname Barrett firstname A. J. journal Journal of Physics A Mathematical and General volume 16 number 10 date 11 July 1983 url http iopscience.iop.org 0305 4470 16 10 027?ejredirect migration DEFAULTSORT Reciprocal Length Category Length Category Physical quantities pt Comprimento rec proco uk ... more details
Image LOA LWL.svg thumb right 300px LOA Length Overall & LWL Waterline Length Image Ship length measurements.png thumb right 300px Detailed hull dimensions The Waterline length originally Load Waterline Length , abbreviated to LWL is a measurement of ship s and boat s. The term denotes the length of the vessel at the point where it sits in the water. It excludes the total length of the boat, such as features that are out of the water. Most boats rise outwards at the Bow ship bow and stern , so a boat may be quite a bit longer than its waterline length. In a ship with such raked stems, naturally the waterline length changes as the draft hull draft of the ship changes, therefore it is measured from a defined loaded condition. Length at the waterline is often abbreviated as lwl , w l , w.l. or wl . This measure is essential in determining a lot of properties of a vessel, such as how much water it displaces, where the bow and stern waves are, hull speed , amount of bottom paint needed, etc. See also Length overall References cite book last Hayler first William B. coauthors Keever, John M. title American Merchant Seaman s Manual year 2003 publisher Cornell Maritime Pr isbn 0 87033 549 9 cite book last Turpin first Edward A. authorlink coauthors McEwen, William A. title Merchant Marine Officers Handbook url edition 4th series date year 1980 month publisher Cornell Maritime Press location Centreville, MD isbn 0 87038 056 X pages chapter chapterurl Ship measurements Category Nautical terms Category Ship construction naval stub fr Longueur de flottaison is Vatnsl na nl Waterlijn no Lengde ved vannlinje sv Konstruktionsvattenlinje ... more details
In physics , coherence length is the wave propagation propagation distance from a coherence physics coherent source to a point where a wave e.g. an electromagnetic wave maintains a specified degree of coherence . The significance is that Interference wave propagation interference will be strong within a coherence length of the source, but not beyond it. This concept is also commonly used in telecommunication engineering. This article focuses on the coherence of Classical physics classical electromagnetic fields. In quantum mechanics , there is a mathematically analogous concept of the Coherence physics Quantum coherence quantum coherence length of a wave function . Formulas In radio band systems, the coherence length is approximated by math L c over n , Delta f , math where c is the speed of light in a vacuum, n is the refractive index of the Medium optics medium , and math Delta f math is the Bandwidth signal processing bandwidth of the source. In optical information transfer communications , the coherence length math L math is given by math L 2 ln 2 over pi n lambda 2 over Delta lambda ... length is usually applied to the optical regime. The expression above is a frequently used approximation ... definition of coherence length has been suggested The coherence length can be measured using a Michelson interferometer and is the optical path length difference of a self interfering laser beam which ... length may be reduced by propagation factors such as dispersion optics dispersion , scattering , and diffraction . Lasers Multimode helium neon laser s have a typical coherence length of 20 cm, while the coherence length of singlemode ones can exceed 100 m. Semiconductor laser s reach ... repeated after cavity length distances up to this long coherence length. See also Portal Physics Coherence time Superconducting coherence length References Reflist 2 FS1037C MS188 DEFAULTSORT Coherence Length Category Electromagnetic radiation Category Optics Category Waves de Koh renzl nge ja ... more details
Unreferenced date December 2009 In chemistry , the path length is defined as the distance that light UV Visible spectrum VIS travels through a sample in an analytical cell. Typically, a sample cell is made of quartz , glass, or a plastic rhombic cuvette with a volume typically ranging from 0.1 mL to 10 mL or larger used in a spectrophotometer . For the purposes of spectrophotometry i.e. when making calculations using the Beer Lambert law the path length is measured in centimeters rather than in meters . In a computer network , the path length is one of many possible router metrics used by a router computing router to help determine the best Routing route among multiple routes to a destination. It consists of the end to end hop count from a source to a destination over the network. More simply, in general computer terminology, it can mean simply the total number of instructions executed from point A to point B in a program Instruction path length . In physics, the path length is defined as the total distance an object travels. Unlike displacement, which is the total distance an object travels from a starting point, path length is the total distance travelled, regardless of where it travelled. DEFAULTSORT Path Length Category Spectroscopy Category Computer networking Category Computing terminology ... more details
Multiple issues unreferenced August 2009 expert subject February 2009 orphan February 2010 In Typography Line length is the width occupied by a block of typesetting typeset character computer text , measured in inches , Pica typography picas and Point typography points . A block of text or paragraph has a maximum line length that fits a determined design. Line length is determined by typographic parameters based on a formal Grid page layout grid and Page layout template with several goals in mind balance and function for fit and readability with a sensitivity to aesthetic style in typography . Typographers adjust line length to aid legibility or copy fit. Text can be flush left and Typographic alignment ragged right , flush right and ragged left , or Justification typesetting justified where all lines are of equal length. In a ragged right setting line lengths vary to create a ragged right edge of lines varying in length. Sometimes this can be visually satisfying. For justified and ragged right settings typographers can adjust line length to avoid unwanted hyphen s, rivers of white space, and orphaned words characters at the end of lines e.g. The , I , He , We . See also Characters per line References reflist Category Typography Category Typesetting typography stub ... more details
Roughness length math z 0 math is a parameter of some vertical wind profile equations that model the horizontal mean wind speed near the ground in the log wind profile , it is equivalent to the height at which the wind speed theoretically becomes zero. In reality the wind at this height no longer follows a mathematical logarithm. It is so named because it is typically related to the height of terrain roughness elements. Whilst it is not a physical length, it can be considered as a length scale a representation of the roughness of the surface. As an approximation, the roughness length is approximately one tenth of the height of the surface roughness elements. For example, short grass of height 0.01m has a roughness length of approximately 0.001m. Surfaces are rougher if they have more protrusions. Forests have much larger rougher lengths than tundra, for example. Roughness length is an important concept in urban meteorology as the building of tall structures, such as skyscrapers, has an effect on roughness length and wind patterns. Terrain description math z 0 math m Open sea, Fetch geography Fetch at least 5 km 0.0002 Mud flats, snow no vegetation, no obstacles 0.005 Open flat terrain grass, few isolated obstacles 0.03 Low crops occasional large obstacles, x H 20 0.10 High crops scattered obstacles, 15 x H 20 0.25 parkland, bushes numerous obstacles, x H 10 0.5 Regular large obstacle coverage suburb, forest 1.0 City centre with high and low rise buildings 2 ref WMO Guide to Meteorological Instruments and Methods of Observation WMO No. 8 page I.5 12 ref References reflist External links http amsglossary.allenpress.com glossary search?id aerodynamic roughness length1 Aerodynamic Roughness Length AMS Glossary http www.webmet.com met monitoring 663.html Surface Roughness Length http www das.uwyo.edu geerts cwx notes chap14 roughness.html Roughness http amsglossary.allenpress.com ... Obukhov length Wind profile power law Log wind profile Displacement height Category Atmospheric dispersion ... more details
The persistence length is a basic mechanical property quantifying the stiffness of a polymer . Informally, for pieces of the polymer that are shorter than the persistence length, the molecule behaves rather like a flexible elastic rod, while for pieces of the polymer that are much longer than the persistence length, the properties can only be described statistically, like a three dimensional random walk . Formally, the persistence length, P , is defined as the length over which correlations in the direction of the tangent are lost. In a more chemical based manner it can also be defined as the average sum of the projections of all bonds j i on bond i in an indefinitely long chain. ref cite book title Statistical Mechanics of Chain Molecules first Paul J. last Flory publisher Interscience Publishers location New York year 1969 isbn 0 470 26495 0 url http openlibrary.org b OL5613440M Statistical mechanics of chain molecules ref Let us define the angle &theta between a vector that is tangent to the polymer at position 0 zero and a tangent vector at a distance L away from position 0, along ... theta rangle e L P , math where P is the persistence length and the angled brackets denote the average over all starting positions. In polymer science jargon the persistence length is considered to be one half of the Kuhn length , the length of hypothetical segments that the chain can be considered as freely joined. The persistence length equals the average projection of the end to end vector on the tangent to the chain contour at a chain end in the limit of infinite chain length. ref cite web ... search 22persistence 20length 22 ref The persistence length can be also expressed using the bending ... length on the order of math 10 16 math m taking in consideration a Young modulus of 0.1 GPa and a radius ... ref Double helical DNA has a persistence length of about 500 Angstrom s. See also Polymer Worm like chain Freely Jointed Chain Kuhn length Paul Flory References Reflist classicalmechanics stub ... more details
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