for cross sections in architecture and engineering Multiview orthographic projection Crosssection Views In geometry , a crosssection is the intersection set theory intersection of a figure in 2 dimensional space with a line, or of a body in 3 dimensional space with a plane, etc. More plainly, when cutting an object into slices one gets many parallel cross sections. Cavalieri s principle states that solids with corresponding cross sections of equal areas have equal volumes. The cross sectional area math A math of an object when viewed from a particular angle is the total area of the orthographic projection of the object from that angle. For example, a cylinder of height h and radius r has math A pi r 2 math when viewed along its central axis, and math A 2 pi rh math when viewed from an orthogonal direction. A sphere of radius r has math A pi r 2 math when viewed from any angle. More generically, math A math can be calculated by evaluating the following surface integral math , A iint limits mathrm top d mathbf A cdot mathbf hat r , math br where math mathbf hat r math is a unit vector pointing along the viewing direction toward the viewer, math d mathbf A math is a surface element with outward pointing normal, and the integral is taken only over the top most surface, that part of the surface that is visible from the perspective of the viewer. For a convex body , each ray through the object from the viewer s perspective crosses just two surfaces. For such objects, the integral may be taken over the entire surface math A math by taking the absolute value of the integrand so that the top ... Crosssectiongeometry sv Tv rsnitt ... 2 iint limits A d mathbf A cdot mathbf hat r math br See also commonscat Cross sections Descriptive geometry Exploded view drawing Graphical projection Plans drawings Geometry stub Category Infographics Category Elementary geometry Category Technical drawing Category Methods of representation ar ... more details
Crosssection can refer to Crosssectiongeometry , the intersection of a 3 dimensional body with a plane Radar crosssection , the unit of measure of how detectable an object is with a radar Crosssection physics , the likelihood of an interaction event between two particles Nuclear crosssection Neutron crosssection Absorption crosssection Photoionisation crosssectionSection fiber bundle , in differential and algebraic geometry and topology, a section of a fiber bundle or sheaf Cross sectional data , a type of one dimensional data set in statistics and econometrics Stratigraphy , the study of geological cross sections Core sample Thin sectionCrosssection biology , a sample such as that created by a microtome disambig de Querschnitt ms Keratan rentas ru ... more details
Unreferenced date December 2009 Orphan date February 2009 Optical CrossSection or OCS is a value which describes the maximum amount of optical flux reflected back to the source. The standard unit of measurement is math frac m 2 sr math . It is dependent on the geometry and the reflectivity at a particular wavelength of an object. Optical crosssection is useful in fields such as LIDAR . In the field of Radar this is referred to Radar CrossSection . Object such as license plates on automobiles has a high optical crosssection to maximized the laser return to the speed detector gun . Flat mirror Optical crosssection of a flat mirror with a given reflectivity at a particular wavelength math r lambda math can be express by this formula. math mbox OCS r lambda frac D 4 1.4884 lambda 2 math Where math D math is the cross sectional diameter of the beam. Note that the direction of the light has to be perpendicular to the mirror surface for this formula to be valid, else the return from the mirror would no longer go back to it source. In order to maximize the return a corner reflector is used. The alignment of a corner reflector with respect to the source is not as critical as the alignment of a flat mirror. Other optical devices Optical crosssection is not limited to reflective surfaces. Optical devices such as telescopes and cameras will return some of the optical flux back to the source, since it has optics that reflect some light. The Optical crosssection of a camera can vary over time due to the camera shutter opening and closing. DEFAULTSORT Optical CrossSection Category Optics ... more details
The scattering crosssection , sub scat sub , is a hypothetical area which describes the likelihood ... section is different from the cross sectional area geometrical crosssection of a particle, and it depends ... amount of scattering in a sparse medium is determined by the product of the scattering crosssection and the number of particles present. In terms of area, the total crosssection is the sum of the cross sections due to absorption crosssection absorption , scattering and luminescence math sigma sigma A sigma S sigma L. math The total crosssection is related to the absorbance of the light ... crosssection and the physical size of the particles, as the scattering crosssection depends ... of an approaching vehicle. That is to say that the scattering crosssection of the water droplets ... is the same. Meteorological range The scattering crosssection is related to the meteorological ... Scattering crosssection, sub scat sub file S05490 ref Units Its SI unit is the square meter , m , although smaller units are usually used in practice. The name crosssection arises because it has ... the path length in centimetre s. To avoid the need for conversion factors, the scattering crosssection ... , the differential crosssection is defined as follows let a beam of intensity math I 0 math measured ... crosssection to be math d sigma over d Omega frac I s I 0 . math Note that this quantity has units ... math in space. The differential crosssection is simply math d sigma over d Omega . math Quantum Mechanics In quantum mechanics , the differential crosssection is defined as follows the wave function ... within a given solid angle. The integral crosssection is the integral of the differential cross ... over d Omega . math A crosssection is therefore a measure of the effective surface area seen by the impinging ... f sub , math vec p f math before and after the collision respectively, the differential crosssection ... . See also Crosssection physics Nuclear crosssection Neutron crosssection Scattering amplitude ... more details
Orphan date February 2009 Deleted image removed Image Crosssection all Pt.JPG thumb right 400px The graph displays the crosssection of all the level of platinum Pt . Photoionisation crosssection in the context of condensed matter physics refers to the probability of a particle usually an electron being emitted from its electronic state . Crosssection in photoemission The photoemission is a useful experimental method for the determination and the study of the electronic states. Sometimes the small amount of deposited material over a surface has a weak contribution to the photoemission spectra , which makes its identification very difficult. The knowledge of the crosssection of a material can help to detect thin layers or 1D nanowires over a Substrate materials science substrate . A right choice of the photon energy can enhance a small amount of material deposited over a surface, otherwise the display of the different spectra won t be possible. ref prl See also ARPES Synchrotron radiation Crosssection physics absorption crosssection Nuclear crosssection References note prl A. Dallmeyer and al . Phys. Rev. B 61, R5133 R5136 2000 External links http ulisse.elettra.trieste.it services elements WebElements.html Elettra s photoemission cross sections calculations Category Electromagnetism Category Condensed matter physics Category Physics physics stub ... more details
also Crosssection physics Absorption electromagnetic radiation Photoionisation crosssection Nuclear crosssection Scattering crosssection Neutron crosssection Mean Free Path Compton edge Compton ...Image Photon Cross Sections.png thumb right 600px Cross sections values for all elements with atomic number Z smaller than 100 collected for photons with energies from 1 keV to 20 MeV. The discontinuities in the values are due to compton edge s which were also shown. Absorption crosssection is a measure for the probability of an absorption process. More generally, the term crosssection physics crosssection is used in physics to quantify the probability of a certain particle particle interaction, e.g., scattering , photoabsorption , etc. Note that light in this context is described as consisting of elementary particle particle s, i.e., photon s. In the context of ozone shielding of ultraviolet light , absorption crosssection is the ability of a molecule to absorb a photon of a particular wavelength and polarization waves polarization .Analogously, in the context of nuclear engineering it refers to the probability of a particle usually a neutron being absorbed by a nucleus. Although the units are given as an area, it does not refer to an actual size area, at least partially because the density or state of the target molecule will affect the probability of absorption. Quantitatively, the number dN of photons absorbed, between the points x and x dx along the path of a beam is the product of the number N of photons penetrating to depth x times the number n of absorbing molecules per unit volume times the absorption crosssection math frac dN dx N n sigma math . The absorption crosssection is closely related to mass absorption coefficient . For a given particle and its energy, the absorption crosssection of the target material can be calculated from mass absorption coefficient using math sigma mu rho m a N A math where math mu rho math is the mass absorption coefficient ... more details
In nuclear physics nuclear and particle physics , the concept of a crosssection is used to express the likelihood ... of a certain substance, the crosssection math sigma math is a hypothetical area measure around ... the crosssection , represented by math sigma math to the total targeted area. This basic ... by a non uniform field. A particular case is scattering . Scattering main Scattering crosssection The scattering crosssection , sub scat sub , is a hypothetical area which describes the likelihood ... crosssection is different from the cross sectional area geometrical crosssection of a particle ... section and the number of particles present. In terms of area, the total crosssection is the sum of the cross sections due to absorption crosssection absorption , scattering and luminescence math sigma sigma A sigma S sigma L. math The total crosssection is related to the absorbance of the light ... A lambda log mathcal T . math Nuclear physics File Crosssection illustration simple.svg right Main nuclear crosssection In nuclear physics , it is convenient to express the probability of a particular event by a crosssection. Statistically, the centers of the atoms in a thin foil can be considered ..., the result can still be expressed in terms of the equivalent stopping crosssection of the atoms ... a neutron can be expressed as the equivalent crosssection of beryllium for this type of reaction. See also Scattering theory Radar The monostatic radar crosssection is defined as 4 times the radio differential crosssection at 180 degrees. Cross sectional area Rutherford scattering References ... hyperphysics.phy astr.gsu.edu Hbase nuclear nucrea.html c3 Nuclear CrossSection http hyperphysics.phy astr.gsu.edu Hbase nuclear crosec.html c1 Scattering CrossSection http www nds.iaea.org IAEA ... Reaction CrossSection http www.iupac.org goldbook C01161.pdf IUPAC Goldbook Definition Collision CrossSection Category Fundamental physics concepts Category Nuclear physics Category Particle ... more details
Mergeto Crosssection physics date October 2008 The nuclear crosssection physics crosssection of a nucleus ... crosssection can be quantified physically in terms of characteristic area where a larger area means a larger probability of interaction. The standard unit for measuring a nuclear crosssection denoted as is the barn unit barn , which is equal to 10 sup 28 sup m or 10 sup 24 sup cm . Cross ... total crosssection s, or for specific processes, distinguishing elastic scattering and inelastic scattering of the latter, amongst neutron crosssection s the absorption crosssection s are of particular ... material. The crosssection obtained in this way is called the total crosssection and is usually ... , and is the unit in which cross sections are usually expressed. Actually the observed cross sections vary enormously. Thus for thermal neutron slow neutron s absorbed by the n, gamma reaction the crosssection in some cases is as much as 1,000 barns, while the cross sections for Nuclear transmutation ... crosssection Nuclear cross sections are used in determining the nuclear reaction rate, and are governed ... crosssection for reaction math x math , units area usually barn unit barns or cm sup 2 sup ... rho A math macroscopic crosssection 1 length Types of reactions frequently encountered are s scattering ... , math sigma a math , etc. A special case is the total crosssection math sigma t math , which gives ... f ... math . Formally, the equation above defines the macroscopic neutron crosssection for reaction ... and microscopic crosssection is that the former is a property of a specific lump of material with its ... section Scattering crosssection References More footnotes date December 2009 Nuclear Reactor Analysis ... coauthors Masud Ahmad , M. Anwar, M.S. Chaudhry title Crosssection measurements with a neutron ... particle s having negligible diameter. Cross sections can be computed for any sort of process, such as capture ... might therefore expect the cross sections for nuclear reactions to be of the order of math pi r 2 ... more details
R is the ratio of the hadron ic crosssection physics crosssection to the muon crosssection in electron positron collisions math R frac sigma 0 e e rightarrow mathrm hadrons sigma 0 e e rightarrow mu mu , math where the superscript 0 indicates that the crosssection has been corrected for initial state radiation. R is an important input in the calculation of the anomalous magnetic dipole moment . ref http arxiv.org abs hep ph 9502298 S. Eidelman and F. Jegerlehner, Z. Phys. C67 585 1995 . ref Experimental values have been measured for center of mass energies from 400 MeV to 150 GeV. ref W. M. Yao et al., J. Phys. G 33, 1 2006 Section 40 ref R also provides experimental confirmation of the electric charge of quark s, in particular the charm quark and bottom quark, and the existence of three quark colors. ref W. M. Yao et al., J. Phys. G 33, 1 2006 Section 9.7 ref A naive calculation of R yields math R 3 sum q e q 2, math where the sum is over all quark flavors with mass less than the beam energy. e sub q sub is the electric charge of the quark, and the factor of 3 accounts for the three colors of the quarks. Quantum chromodynamics QCD corrections to this naive formula have been calculated. ref S.G. Gorishny et al. , Phys. Lett. B259 144 1991 ref Notes reflist Category Scattering Category Particle physics particle stub ... more details
The total neutron crosssection of an isotope of a chemical element is the effective crosssection physics cross sectional area that an atom of that isotope presents to neutron scattering and neutron absorption absorption . Scattering versus absorption When a neutron approaches an atomic nucleus, it scatters or is absorbed. If absorbed, the atomic nucleus moves up on the table of isotopes by one position. For instance, U 235 becomes U 236 with the indicating the nucleus is highly energized. This energy has to be released and the release can take place through any of several mechanisms. The simplest way for the release to occur is for the neutron to be ejected by the nucleus. If the neutron is emitted immediately, it acts the same as in other scattering events. The nucleus may emit gamma radiation. The nucleus may sup sup decay, where a neutron is converted into a proton, an electron and an electron type antineutrino the antiparticle of the neutrino About 81 of the U 236 nuclei are so energized that they fission, releasing the energy as kinetic motion of the fission fragments, also emitting between one and five free neutrons. Nuclei that fission as their predominant decay method after neutron capture include U 233, U 235, U 237, Pu 239, Pu 241. Nuclei that predominantly absorb neutrons ... crosssection The scattering crosssection can be further subdivided into coherent scattering and incoherent scattering , which is caused by the spin physics spin dependence of the scattering crosssection and for a natural sample, presence of different isotope s of the same element in the sample. Since neutrons interact with the nuclear potential , the scattering crosssection varies with the atomic ... . The total crosssection for hydrogen is over 10 times that of deuterium, mostly due to the large ... by CrossSection Thermal Neutron Capture What does this mean? Coherent scattering In this nuclear process ... links http www.ncnr.nist.gov resources n lengths Neutron scattering lengths and cross sections ... more details
Image Sigma invader RCS.png thumb 300px Typical RCS diagram A 26 Invader Radar crosssection RCS is a measure of how detectable an object is with a radar . A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy. A number of different factors determine how much electromagnetic energy returns to the source such as material of which the target is made absolute size of the target relative size of the target in relation to the wavelength of the illuminating radar the incident angle angle at which the radar beam hits a particular portion of target ... the RCS is approximately only a property of the target. Radar crosssection is used to detect planes ... meters math sigma math radar crosssection of the target meters squared math A eff math effective ... density is intercepted by the target with radar crosssection math sigma math , which has units of area ... reduces radar crosssection for Stealth ship stealth . Main Stealth technology RCS reduction is chiefly ... the radar crosssection of such a stealth body, one would typically do one dimensional reflection ... to calculate the diffraction coefficients of corners and points. The crosssection can then be calculated ... ADA402379 ref ref author SciTech Publishing year 2004 title Radar CrossSection ref ref cite web author IEEE Transactions on Antennas and Propagation year 2008 title A Method to Measure Radar CrossSection Parameters of Antennas url http ieeexplore.ieee.org stamp stamp.jsp?tp &arnumber 4685914 ... Reflist Shaeffer, Tuley and Knott. Radar CrossSection . SciTech Publishing, 2004. ISBN 1 891121 ... to measure radar crosssection parameters of antennas http sourceforge.net projects puma em Puma EM ... Informally, the RCS of an object is the cross sectional area of a perfectly reflecting sphere ... sphere would produce stronger reflections. Thus, RCS is an abstraction The radar cross sectional area of an object does not necessarily bear a direct relationship with the physical cross ... more details
CrosssectiongeometryCrosssection , depicting the Geologic fault fault that affects the middle and final courses of the Trabancos River as well as the sequence of its river terrace s Category Geographic images Spanish versi n in Image Corte geomorfol gico del Trabancos.gif 200px http commons.wikimedia.org wiki Image Corte geomorfol gico del Trabancos.gif Commons PD self date May 2007 ... more details
The United States National Radar Crosssection Facility is located at Holloman AFB , New Mexico . See also Portal United States Air Force F 117A Nighthawk HAVE BLUE References http www.eglin.af.mil library factsheets factsheet.asp?id 6478 Eglin AFB Public Affairs 46th Test Wing Fact Sheet DEFAULTSORT National Radar CrossSection Facility Category United States Air Force USAF stub ... more details
Summary A crosssection through the first Dodson Breaker, which stood in Plymouth, Luzerne County, Pennsylvania until it was destroyed by fire in 1899. The drawing was published in Transactions of the American Institute of Mining and Metallurgical Engineers, Vol. 66, published in 1922. Licensing PD US ... more details
Move to Commons Summary Information Description Orange crosssection picture with legend. Source http commons.wikimedia.org wiki Image Perpendicular orange.png Date 2006, December 15 Author w user Ekko Ekko picture author user Juan de Vojn kov Juan de Vojn kov compilation author Permission other versions Licensing self GFDL Cc by sa 2.5 migration relicense ... more details
Summary Information Description crosssection of Gemini 2 heatshield Source I User Bubba73 Bubba73 User talk Bubba73 sup You talkin to me? sup , created this work entirely by myself. Date June 22, 2010 Author User Bubba73 Bubba73 User talk Bubba73 sup You talkin to me? sup , Jud McCranie other versions Licensing self cc by sa 3.0 GFDL migration redundant ... more details
Information Description SEM crosssection of a thermal bump Source self made, Nextreme Thermal Solutions Date 20 15, 20 March 2008 UTC Author Nextreme Thermal Solutions Permission GFDL self migration relicense Permission is granted to copy, distribute and or modify this document under the terms of the Wikipedia Text of the GNU Free Documentation License GNU Free Documentation License , Version 1.2 or any later version published by the Free Software Foundation with no Invariant Sections, no Front Cover Texts, and no Back Cover Texts. Subject to Wikipedia General disclaimer disclaimers . ... more details
Summary This image is derived from http commons.wikimedia.org wiki Image Chest and heart cross section.svg with electrodes and field lines added to illustrate EIT by Bill Lionheart User Billlion . The original attribution is specified below Patrick J. Lynch illustrator C. Carl Jaffe MD cardiologist Yale University Center for Advanced Instructional Media Medical Illustrations by Patrick Lynch, generated for multimedia teaching projects by the Yale University School of Medicine, Center for Advanced Instructional Media, 1987 2000. Patrick J. Lynch, http patricklynch.net Creative Commons Attribution 2.5 License 2006 no usage restrictions except please preserve our creative credits Patrick J. Lynch, medical illustrator C. Carl Jaffe, MD, cardiologist. http creativecommons.org licenses by 2.5 Licensing cc by 2.5 ... more details
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