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Topic: Shell model

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Magic number (physics)

Interacting boson model

Liquid drop model

Electronic structure

Valence shell

Atomic nucleus

Nuclide

Molecular orbital

Nuclear decay

Oxidation number

Nuclear physics

Gamma decay

Electron shell

Valence electron

Subatomic particle

	Shell Model of Nucleus
		Part of the motivation for the shell model of nuclear structure is the existance of "magic numbers" of neutrons and protons at which the nuclei have exceptional stability, implying some kind of "closed shell".
		Iron-56 is an even-even nucleus and therefore expected to be particularly stable because of the Pauli contribution in the liquid drop model, but does not have magic numbers of either N or Z. It is exceeded in binding energy only by nickel-62 (the most stable nuclide) and iron-58.
		The common unit for cross-sections is the barn, and the vertical axis on the illustration is labeled in millibarns.
	hyperphysics.phy-astr.gsu.edu /hbase/nuclear/shell2.html (598 words)

	The Shell Model
		When a shell is full (that is, when the nucleons have used up all of the possible sets of quantum number assignments), a nucleus of unusual stability forms.
		When all the protons or neutrons in a nucleus are in filled shells, the number of protons or neutrons is called a "magic number." Some of the magic numbers are 2, 8, 20, 28, 50, 82, and 126.
		The shell model calculations of these transition probabilities agree quite well with the measured rates even though different decay mechanisms are at work in each case.
	www.lbl.gov /nsd/education/ABC/wallchart/chapters/06/1.html (560 words)

	Kids.Net.Au - Encyclopedia > Shell model (Site not responding. Last check: )
		The nuclear shell model is a model of the nucleus in nuclear physics.
		Recall that in the atomic shell model, the electrons populate shells, and once a shell is filled, there is a significant drop in the binding energy for the next electron added.
		Note that the shells exist for both protons and neutrons individually, so that we can speak of "magic nuclei" where one nucleon type is at a magic number, and "doubly magic nuclei", where both are.
	www.kids.net.au /encyclopedia-wiki/sh/Shell_model (194 words)

	NationMaster - Encyclopedia: Shell model
		In nuclear physics, the nuclear shell model is a model of the atomic nucleus.
		Recall that in the atomic shell model, the electrons populate shells, and once a shell is filled, there is a significant drop in the binding energy for the next electron added.
		Part of the motivation for the shell model of nuclear structure is the existance of "magic numbers" of neutrons and protons at which the nuclei have exceptional stability, implying some kind of "closed shell".
	www.nationmaster.com /encyclopedia/Shell-model (800 words)

	The Shell Model of Nuclear Structure
		The interpretation is that the electrons form shells and when a shell is filled the configuration is exceptionally stable and requires a lot of energy to knock an electron out of a filled shell.
		The study of nuclear shell structure began with an investigation of the changes in the binding energy of nuclei as the neutron number is changed by one.
		This model is embodied in the Semiempirical Formula for Nuclear Masses, which gives good explanation for nuclear masses except for isolated cases such as the alpha particle, the
	www.sjsu.edu /faculty/watkins/shell.htm (1041 words)

	Palaeos Metazoa: Mollusca: Shell Morphology
		Shell morphology, according to the mathematical model of David Raup.
		Of later studies regarding the theoretical morphology of the coiled shell, the work of David Raup (1962, 1966) is the best-known.
		The model specifies the shape of the aperture, or generating curve, the axis of coiling, the size ratio (W) of successive generating curves, the distance (D) of the generating curve from the axis, and the proportion (T) of the height of one generating curve that is covered by the successive gyres."
	www.palaeos.com /Invertebrates/Molluscs/Mollusca.Shell.html (956 words)

	Shell model
		The main ingredients for the success of the nuclear shell model are the idea of independent-particle motion in nuclei, and strong spin-orbit coupling, which results in a sizeable splitting of the angular-momentum levels and yields the correct sequence of energy levels and shell closures.
		In nuclear astrophysics, the efforts to include the microphysical processes as described by the shell model in a consistent fashion into the codes for macrophysical processes such as stellar evolution (element synthesis in the s-process) and supernova explosions (r-process) are continuing.
		Referring again to the origins of the shell model, Sharon McGrayne talked about Maria Goeppert-Mayer, her work in the US - which was not always favored by the external conditions -, her discussions with contemporary physicists such as E. Fermi, the evolution of the shell model and her cooperation with Jensen.
	www.rzuser.uni-heidelberg.de /~q61/smhd.html (1150 words)

	Turnaround model - Shell Chemicals (Site not responding. Last check: )
		By using a pool of knowledge and experience gained from similar turnarounds at other Shell chemicals plants, the new approach uses almost military-style precision in preparing and executing a cycle of maintenance tasks on a strict schedule, and to a tight budget.
		Shell Chemicals people and contractors worked a total of 250,000 work-hours without incident in a project which at its peak involved more than 900 people working simultaneously.
		In the meantime, a fourth generation of the Shell SM/PO technology which reduces capital equipment costs, improves performance and reduces energy consumption is already off the drawing board and ready for implementation.
	www.shellchemicals.com /magazine/1,1098,295-article_id=162,00.html (822 words)

	Shell Model of Nucleus
		But dense-gas type models of nuclei with multiple collisions between particles didn't fit the data, and remarkable patterns like the "magic numbers" in the stability of nuclei suggested the seemingly improbable shell structure.
		The parity of the state can also be predicted, so the single particle shell model has shown itself to be of significant benefit in characterizing nuclei.
		The shell model of the nucleus presumes that a given nucleon moves in an effective attractive potential formed by all the other nucleons.
	hyperphysics.phy-astr.gsu.edu /hbase/nuclear/shell.html (1067 words)

	[No title]
		Shell Model Monte Carlo (SMMC) methods have overcome the severe limitations of the conventional diagonalization techniques and now allow complete 0 calculations with realistic interactions for nuclei, a task which appeared impossible only a couple of years ago.
		If shell and pairing effects can be ignored, the empirical Bethe-Weizsäcker formula suggests that an increase of the symmetry energy with temperature should be reflected in an increase of the difference of excitation energies between isobars with temperature.
		As the large shell gap between the occupied (g_9/2)-orbital and the other orbitals in the (0 g-1d-2s) shell (Delta E 6 MeV) suppresses correlations involving the higher orbitals, there should be little hindrance of the transformation of valence (g_9/2)-protons into (g_7/2)-neutrons by the GT_+ operator.
	www.krl.caltech.edu /Projects/shellmod.html (2789 words)

	Model Info SEC Shell and Tube Heat Exchangers
		SEC Shell and Tube heat exchangers are manufactured with stainless steel tubes and carbon steel shell as our standard unit.
		These shell and tube heat transfer devices are engineered to meet to a wide variety of applications.
		Every shell and tube unit is designed, manufactured, and tested as per the quality requirements of the ASME code, Section VIII Division #1 and ISO 9002.
	www.secshellandtube.com /model-info.html (164 words)

	Shell Model of Molecular Formation (Site not responding. Last check: )
		To construct the model for carbon, we determine its outer shell radius to be 85pm using the Java applet at my atom simulation page.
		The model assumes that the electrons of the inner shells interact with less influence and thus cancel the positive charges of the protons in the nucleus, leaving us with the simple model of a single electron orbiting a net charge of +1.
		The model may then be extended to accomodate multiple atoms bound to a central atom as shown in the figure below of the hydrocyanic acid molecule (HCN).
	www.orbits.00space.com /shellmodel.html (824 words)

	Method of restoring the shape of a flexible-shell model (US3946095)
		A method of restoring the shape of an anatomical model comprising placing mold inserts in the undercut portions of the model, charging the model with a foaming thermosetting plastic, and enclosing the model and mold inserts in a fixture.
		As the foaming thermosetting plastic expands, the model is pressed against the inserts and the fixture causing the model to assume the shape of the fixture and inserts.
		foaming and curing the foamable thermosetting plastic in the flexible-shell model while the flexible-shell model is enclosed in the fixture and is forced outward by the foaming thermosetting plastic against the fixed standard shape of the fixture and the inserts.
	www.delphion.com /details?pn10=US03946095 (280 words)

	Shelton Corporation - Shellmaster Products - Model 950 (Site not responding. Last check: )
		Model 950 has virtually 100% deveining capability with peeler rollers for stripping the shell away from the shrimp.
		Shell Master® Model 950 was designed to be user friendly, and refined with expert input from shrimp processors to eliminate problems associated with the current mechanical shrimp processing industry.
		The cost of Model 950 is less than single-step hand peeling where you use a tool—because with that method, in one stroke you get the vein out, the vein flap, and shell off, but the cut is ragged and that method doesn’t work well on soft shrimp.
	www.shrimpbutler.com /model950.htm (666 words)

	Concrete Buckle-Shell Model Study (Site not responding. Last check: )
		A method of forming latex-modified fiberglass-reinforced concrete shell roof structures with pneumatically supported foamed plastic forms is presented.
		Observations of the shell model during the application of the mortar indicated that on the prototype shell concrete application will have to proceed in layers and in a planned pattern of progress over the surface of the shell.
		The shell structure could be realized either as a concrete shell or as a plastic sandwich shell as witnessed by the plastic foam form.
	www.pubs.asce.org /WWWdisplay.cgi?5013149 (129 words)

	gefen.htm
		A very successful one is called the shell model, where it every nucleon is moving in some average potentia well due to its interaction with all other nucleons.
		It is possible to use shell model states only with a "tamed" or effective interaction which,however, is extremely difficult to obtain from the free nucleon interaction.
		Shell model analysis of nuclear energies in Proc.
	www.weizmann.ac.il /physics/staff/Talmi.htm (347 words)

	Nobel Prize in Physics 1963 - Presentation Speech
		It was found during the 1920's and in particular during the 1930's that the protons and the neutrons each form particularly stable systems in an atomic nucleus when the numbers of either kind of nucleons is one of the so-called magic numbers 2, 8, 20, 50, 82 and 126.
		They gave convincing evidence for the great importance of the shell model in systematizing this material and predicting new phenomena concerning the ground state and the low excited states of the nuclei.
		Your work on the shell model which you started independently and then pursued in collaboration has shed new light on the structure of atomic nuclei.
	www.nobelprize.org /physics/laureates/1963/press.html (1034 words)

	[No title] (Site not responding. Last check: )
		This allows the Secure Shell Transport Model for SNMP to be designed and documented as independent and self- contained, having no direct impact on other modules, and allowing this module to be upgraded and supplemented as the need arises, and to move along the standards track on different time-lines from other modules.
		This transport model is designed to meet the security and operational needs of network administrators, maximize usability in operational environments to achieve high deployment success and at the same time minimize implementation and deployment costs to minimize the time until deployment is possible.
		The sending transport model passes unencrypted messages from the dispatcher to SSH to be encrypyed, and the receiving transport model accepts decrypted incoming messages from SSH and passes them to the disptacher.
	www.ietf.org /internet-drafts/draft-ietf-isms-secshell-05.txt (8257 words)

	Trail Model Soft-Shell Jacket: Soft-Shell Jackets at L.L.Bean (Site not responding. Last check: )
		The wind- and water-resistant nylon/spandex shell is exceptionally breathable, and it stretches with you when you reach and move.
		An innovation in outerwear, soft-shell jackets combine a highly wind- and water-resistant shell with a soft interior layer for warmth.
		The key to their comfort lies in their breathability – soft shells efficiently move perspiration away from your skin where it can quickly evaporate.
	www.llbean.com /webapp/wcs/stores/servlet/CategoryDisplay?qs=50904242&page=trail-model-soft-shell-jacket&categoryId=47215&parentCategory=500572&storeId=1&catalogId=1&langId=-1 (170 words)

	The kinetic shell model
		) developed their so-called kinetic shell model, which seeks to test the collisionless response of protons in the solar corona and solar wind to the resonant dissipation of ion cyclotron waves propagating outwardly from the Sun.
		The fixed shells in the model are argued to evolve on the large non-resonant timescale (expansion time), corresponding to the shell-averaged forces of gravity, charge-separation electric field, and magnetic mirror, which all are contained in Equation (9
		Since according to the authors the model describes the maximal wave dissipation, it was concluded that heating and acceleration of protons in coronal holes are not caused by the dissipation of parallel propagating ion-cyclotron waves.
	solarphysics.livingreviews.org /Articles/lrsp-2006-1/articlesu27.html (771 words)

	Shell Model of Nucleus
		The basis of this prediction is the aufbau principle, which assumes that protons are added to an nucleus, one at a time, starting with the lowest energy orbital, until all of the protons have been placed in an appropriate orbital.
		For an atom to fill its 2nd proton shell, 8 protons would be needed : 2 to fill the 1st shell and 6 to fill the 2nd.
		In the atomic shell model, the shells are filled with protons in order of increasing natural numbers series, producing the magic numbers.
	milan.milanovic.org /math/english/atom/nucleus.html (431 words)

	3D-2D Coupling (Site not responding. Last check: )
		The model has a width of 80 mm and a thickness of 5 mm, while the diameter of the hole is 20 mm.
		Figure 2 illustrates a model of a stiffened panel in an aircraft structure, where one side of the shell edges was fully constrained while the other side was subjected to a pressure loading.
		3D modelling with 20-noded bricks was used for the tee joint as a means for appropriate load transfer between the wheel centre and the rim, while eight-noded quadratic shell elements were coupled to this connection at a distance of two thickness away from the blended corners.
	sog1.me.qub.ac.uk /Research/coupling/3d-2d/solid_shell.php (1141 words)

	Model Site - Shell V-Power
		Introduction to Shell’s overall fuel message about improving the way people move.
		Brief description about what Shell V-Power is and its main benefits – helping to enhance driving power and deliver superior performance.
		Shell Advance motorcycle oils protect your bike - so you get the most out of it for longer.
	www.shell.com /home/Framework?siteId=model-en&FC2=/model-en/html/iwgen/leftnavs/zzz_lhn4_2_15.html&FC3=/global/shell_for_motorists/fuels/v_power_pkg/introduction.html (74 words)

	The Shell Model
		In the Shell model, atomic interactions are represented by potentials between each pair of atoms in the system.
		The equilibrium distance between the core and shell is a representation of the electronic polarization of that atom.
		For shells there is also an additional contribution to the interaction due to the elastic force in the spring connecting core and shell.
	www.fyslab.hut.fi /~asf/physics/thesis1/node23.html (540 words)

	ShellModel
		A shell model is one in which the system is thought to consist of individual particles moving in bound orbitals in response to the remainder of the system.
		The nuclear shell model potential should represent the average interaction of all the other nucleons exerted on any one of the nucleons in the nucleus.
		In the extreme single particle model, one assumes that the ground state of an odd-A nucleus is determined by the quantum numbers of the odd nucleon after the A-1 other nucleons have coupled to spin 0.
	dwb.unl.edu /Teacher/NSF/C03/C03Links/www-highspin.phys.utk.edu/7Ebingham/ShellModel.html (1923 words)

	News \| Gainesville.com \| The Gainesville Sun \| Gainesville, Fla. (Site not responding. Last check: )
		In nuclear physics, the nuclear shell model is a model of the atomic nucleus which uses the Pauli principle to describe the structure of the nucleus in terms of energy levels.
		The model was developed in 1949 following independent work by several physicists, most notably Eugene Paul Wigner, Maria Goeppert Mayer and J.
		The shell model is partly analogous to the atomic shell model which describes the arrangement of electrons in an atom, in that a filled shell results in greater stability.
	www.gainesville.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=shell_model (356 words)

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