In mathematics, a rigid transformation or a Euclidean transformation is a transformation from a Euclidean space to itself that preserves distances between every pair of points isometry . Rigid transformations include rotation mathematics rotations , translation mathematics translations , reflection mathematics reflections , or their combination. Sometimes reflections are excluded from the definition of a rigid transformation by imposing that the transformation also preserve the orientation mathematics handedness of figures in the Euclidean space a reflection would not preserve handedness for instance, it would tranform a left hand into a right hand . To avoid ambiguity, this smaller class of transformations is known as proper rigid transformations informally, also known as roto translations . In general, any proper rigid transformation can be decomposed as a rotation followed by a translation, while any rigid transformation can be decomposed as an improper rotation followed by a translation or as a sequence of reflections . Any object will keep the same shape and size after a proper rigid transformation, but not after an improper one. All rigid transformations are affine transformations . Rigid transformations which involve a translation are not linear transformation s. Not all transformations are rigid transformations. An example is a shear mathematics shear , which changes two axes in different ways, or a similarity transformation , which preserves angles but not lengths. The set of all proper and improper rigid transformations is a group mathematics group called the Euclidean group , denoted E n for n dimensional Euclidean spaces . The set of proper rigid transformation is called special Euclidean group, denoted SE n . In mechanics , proper rigid transformations in a 3 ... displacement of Rigid body rigid bodies . Formal definition A rigid transformation is formally ... , and t is a vector giving the translation of the origin. A proper rigid transformation has, in addition ... more details
File Magirus Deutz L117 berlandbus.jpg thumb A Magirus Deutz L117 rigid bus also a de Standard Bus standard bus see text . A rigid bus either a motor bus or trolleybus is a vehicle used in public transportation with a single, rigid chassis. A bus of this type is to be contrasted with an articulated bus articulated or bi articulated bus , ref name handbook which will have two or more two rigid sections linked by a kinematic pair pivoting joint , and also with a trailer bus , which is formed out of a bus bodied semi trailer pulled by a conventional tractor unit . The term rigid bus is used mainly in British English and Australian English and usually only when distinguishing such buses from articulated buses, such as when describing a fleet that includes both types. In the case of two axle buses, which must be single chassis, rigid vehicles, British English often refers to such vehicles as two axle buses, only using the term rigid when referring to vehicles with three or more axles, which can be either rigid or articulated. The term rigid bus is not used in American English , where the distinction is commonly made using the term non articulated bus or, when the context is clear, standard bus. However, the expression standard bus can be confusing, because it is sometimes used, in other English speaking countries, to refer to a uniform bus design developed for and by a number of European bus manufacturers, in two model generations, between the 1960s and the end of the 20th century. Examples of this latter type of de Standard Bus standard bus include the Mercedes Benz O305 and the Mercedes Benz O405 types, each of which, in both rigid and articulated forms, was widely acquired and used by bus operators in English speaking countries outside North America. ref name veerkamp Rigid ... have either two axles or multi axle bus multi axles . However, the expression rigid bus is seldom ... a rigid chassis. Single decker rigid buses are used mainly on bus lines with an average ridership ... more details
In category theory , a branch of mathematics , a rigid category is a monoidal category where every object is rigid, that is, has a dual object dual X sup sup the internal Hom X, 1 and a morphism 1 &rarr X &otimes X sup sup satisfying natural conditions. The category is called right rigid or left rigid according to whether it has right duals or left duals. They were first defined by Dold and Puppe in 1978 ref cite journal last1 Dold first1 A. last2 Puppe first2 D. title Duality, trace and transfer journal Proceedings of the International Conference on Geometric Topology Warsaw, 1978 , publisher PWN year 1980 pages 81 102 ref . Definition There are at least two equivalent definitions of a rigidity. An object X of a monoidal category is called left rigid if there is an object Y and morphisms math eta X mathbf 1 to X otimes Y math and math epsilon X Y otimes X to mathbf 1 math such that both compositions File definition rigid object 1.png are identities. A right rigid object is defined similarly. An object X of a monoidal category is called left rigid if it has a left dual X sup sup X, 1 and a morphism math kappa mathbf 1 to X otimes X math such that the compositions File definition rigid object 2.png Citation needed date August 2011 are identities. The definition of a right rigid object .... right rigid, and X sup sup X sup 1 sup . The operation of taking duals gives a contravariant functor on a rigid category. Uses One important application of rigidity is in the definition of the trace of an endomorphism of a rigid object. The trace can be defined for any rigid category such that taking ... functor. Then for any right rigid object X , and any other object Y , we may define the isomorphism ... 1 math , so math tr f in End mathbf 1 math . We may continue further and define the dimension of a rigid ... relation internal Hom s. If X is a left rigid object, then every internal Hom of the form X, Z exists and is isomorphic to Z &otimes Y . In particular, in a rigid category, all internal Hom s exist ... more details
Image Wfm rigid raider.jpg thumb right 300px A Royal Marines Rigid Raider Image Raiderex.jpg thumb right 300px Royal Marines Rigid Raider exercise in Scotland Image Rigidraider.jpg thumb right 300px Royal Marines Rigid Raider at speed The Rigid Raider is a series of fast patrol assault boat made by RTK Marine , a subsidiary of Halmatic now part of BAE Systems Surface Ships . They are in service with many armed forces, including the Royal Marines , the Special Boat Service SBS and Royal Engineers . The boats have a glass reinforced plastic hull and are fitted with single 115 hp Mariner Optimax outboard motor s. Mk 1 Coxswain plus 8 troops or 1000 kg cargo Weight 0.87 tonnes Length 5.2 meters Speed 30 knots fully laden , 50 knots light Mk 2 No Longer In Service Coxswain plus 10 troops plus 650 kg of equipment or 20 troops. Weight 1.31 tonnes Length 6.5 meters Speed 30 knots fully laden External links http www.vosperthornycroft.co.uk halmatic product.asp?itemID 424&catid 247 Rigid Raiding Craft at http www.vosperthornycroft.co.uk VT Group page References Reflist Category Active amphibious warfare vessels of the United Kingdom Category Landing craft Category Military equipment of the Falklands War Category British Army equipment Category Royal Marines Navy stub ... more details
orphan date February 2010 Refimprove date March 2012 Infobox musical artist name This Rigid Empire image ThisRigidEmpireAugust2009.jpg caption This Rigid Empire at a Summer 2009 photoshoot image size landscape background group or band origin Orillia , Ontario , Canada genre Pop punk , punk rock , pop rock years active 2008 present label KcIrTaP Productions ref cite web url http www.youtube.com xkcirtapproductionsx title xkcirtapproductionsx publisher YouTube date 2011 11 30 accessdate 2012 03 22 ref associated acts website URL myspace.com thisrigidempie current members Benjamin Taylor Vocals Rhythm Guitar Guitar br Patrick Attenborough Vocals Bass Guitar Bass br Reid Goobie Backup Vocals Lead Guitar Guitar br Jordan Nieuwhof Drums past members Sean Mercer Drums This Rigid Empire is a pop rock band from Orillia, Ontario Orillia , Ontario , Canada . They are best known for their cover of T.I. s Whatever You Like T.I. song Whatever You Like and their other covers of hit pop songs. Through online publicity and word of mouth This Rigid Empire has established a steady following. This Rigid Empire will be releasing their debut album Battery Powered Muffin in May 2010. ref cite web url http ..., What s Up? van This Rigid Empire & 124 Debut Album Out Now & 124 op Myspace publisher Blogs.myspace.com ... name changes such, as Exits and Scythe, the name This Rigid Empire was decided upon. The band came up ... selecting words. The name has since remained the same. This Rigid Empire has undergone a few member ... Taylor. Current 2008 present After a three year hiatus This Rigid Empire was reborn after Patrick and Ben met Sean Mercer. Sean joined This Rigid Empire, making the band a three piece. They began ... Powered Muffin . Discography Battery Powered Muffin 2010 This Rigid Empire started recording their debut ... links http www.myspace.com thisrigidempire This Rigid Empire at Myspace http www.facebook.com pages This Rigid Empire 10180643735 This Rigid Empire s Official Facebook Fan Page DEFAULTSORT This Rigid ... more details
Rigid origami is a branch of origami which is concerned with folding structures using flat rigid sheets joined by hinges. It is a part of the study of the mathematics of paper folding , it can be considered as a type of Linkage mechanical mechanical linkage , and has great practical utility. For instance it was used in the construction of large solar panel arrays that have to be folded before deployment. There is no requirement that the structure start as a flat sheet &mdash for instance shopping bag s with flat bottoms and airbag s are studied as part of rigid origami. Mathematics The number of standard origami bases that can be folded using rigid origami is restricted by its rules. ref cite book author Demaine, E. D authorlink Erik Demaine title Folding and Unfolding. Doctoral Thesis place University of Waterloo, Canada year 2001 url http etd.uwaterloo.ca etd eddemaine2001.pdf ref Rigid origami does not have to follow the Huzita Hatori axioms , the fold lines can be calculated rather than having to be constructed from existing lines and points. However Kawasaki s theorem and Maekawa s theorem are still applicable. The Bellows conjecture Bellows theorem says that a flexible polyhedron has constant volume when flexed. ref cite journal title The bellows conjecture journal Beitr ge zur Algebra und Geometrie volume 38 issue 1 pages 1&ndash 10 year 1997 author R. Connelly, I. Sabitov, A. Walz ref The napkin folding problem asks whether it is possible to fold a square so the perimeter of the resulting flat figure is increased. That this can be solved within rigid origami was proved by A.S. Tarasov in 2004. Applications The Miura fold is a rigid fold that has been used to deploy large solar panel arrays for space satellites. Robert J. Lang has applied origami to the problem of folding ... has popularised flexagon s which are a form of rigid origami and the flexatube. ref cite journal journal ... url http mars.wnec.edu th297133 rigid rigid.html title Rigid Origami author Tom Hull Dr. Tom Hull ... more details
, showing the framework of a rigid airship. A rigid airship is a type of airship in which the Aerostat ... pressurized airships and semi rigid airship s. ref name Mueller cite journal last Mueller first ... quote In general, airships fall into one of two categories pressurized or rigid. With pressurized ... lifting gas and the external atmosphere. With rigid airships, the hull is formed by a lightweight ... Zeppelin II and the Hindenburg were both rigid airships. Pressure airships are sometimes made semi rigid by adding a structural keel to share the bending loads generated from aerodynamic forces. ref ... 4 6, 8 ref Rigid airships were produced and relatively successfully employed from the beginning ... disaster ignited on May 6, 1937. Terminology Although rigid airship is the proper formal term, these aircraft ... since both semi rigid airship s and non rigid airship s are dirigible, i.e. steerable , zeppelin ... , or the big rigids . Early days By 1874 several people had conceived of a rigid dirigible in contrast to non rigid powered airships which had been flying since 1852 . Frenchman Joseph Spiess had published a rigid airship proposal in 1873 but failed to get funding. ref Dooley Dooley A.174 citing Hartcup Hartcup p89 ref Ferdinand von Zeppelin Count Zeppelin had outlined his thoughts of a rigid ... Germany in rigid airship technology. According to a 2001 PBS documentary, much of Britain s knowledge ... September 2008 . France France s only rigid airship was built by Alsace Alsatian Joseph Spiess using ... achievements with a bronze frieze of his rigid airship. Expand section date June 2008 Deleted image ... 2008 In 1900, Count Ferdinand von Zeppelin began trials with a rigid airship based on the theories ... Jewish descent. Germany had over twenty very large lighter than air rigid airships by the beginning ... airships were semi rigid dirigibles, they were different from the rigid Zeppelins in that they typically ... accessdate 21 January 2010 ref harv postscript None ref United States The United States rigid ... more details
Classical mechanics cTopic Core topics Image Flight dynamics with text.png right thumb The position of a rigid ... Springer ref In physics , a rigid body is an idealization of a solid Physical body body of finite ... between any two given Point geometry point s of a rigid body remains constant in time regardless of external ... relativity , objects can normally be assumed to be perfectly rigid if they are not moving near the speed of light . In classical mechanics a rigid body is usually considered as a continuous mass distribution, while in quantum mechanics a rigid body is usually thought of as a collection of point ... are often seen as rigid bodies see Rotational spectroscopy Classification of molecules based on rotational behavior classification of molecules as rigid rotors . Kinematics Linear and angular position The position of a rigid body is the Coordinate system Examples position of all the particles ... is rigid, namely that all its particles maintain the same distance relative to each other. If the body is rigid, it is sufficient to describe the position of at least three non collinear ... also known as orientation , or attitude of the body. Thus, the position of a rigid body has two components ... mechanics kinetic quantities describing the motion of a rigid body, such as linear and angular velocity ... coordinate system and its tip at an arbitrary point of interest on the rigid body, typically coinciding ... orientation of a rigid body, including a set of three Euler angles , a quaternion , or a Direction cosines ... system , from which the motion of the rigid body is observed. For instance, a basis set ..., and b sub 3 sub is given by the cross product math b 3 b 1 times b 2 math . In general, when a rigid ... of a rigid body can be viewed as a hypothetic translation and rotation roto translation of the body ... of a rigid body is a Vector geometry vector quantity, equal to the time derivative time rate of change ... translational motion motion with no rotation , all points on a rigid body move with the same velocity ... more details
In mathematics, rigid cohomology is a p adic cohomology theory introduced by harvtxt Berthelot 1986 . It extends crystalline cohomology to schemes that need not be proper or smooth, and extends Monsky Washnitzer cohomology to non affine varieties. References Citation last1 Berthelot first1 Pierre author1 link Pierre Berthelot mathematician title G om trie rigide et cohomologie des vari t s alg briques de caract ristique p url http www.numdam.org item?id MSMF 1986 2 23 R3 0 id MathSciNet id 865810 year 1986 journal M moires de la Soci t Math matique de France series Nouvelle S rie issn 0037 9484 issue 23 pages 7 32 Citation last1 Le Stum first1 Bernard title Rigid cohomology url http www.cambridge.org catalogue catalogue.asp?isbn 0521875242 publisher Cambridge University Press series Cambridge Tracts in Mathematics isbn 978 0 521 87524 0 id MathSciNet id 2358812 year 2007 volume 172 Citation last1 Tsuzuki first1 Nobuo title Rigid cohomology id MathSciNet id 2560145 year 2009 journal Mathematical Society of Japan. Sugaku Mathematics issn 0039 470X volume 61 issue 1 pages 64 82 Category Algebraic geometry Category Cohomology theories Category Homological algebra ... more details
Unreferenced date December 2007 Cleanup date December 2007 Rigid panel insulation is made from fibrous materials fiberglass, rock and slag wool or from plastic foam . They are sometimes sold in sections designed to fit tightly in standard wall cavities. When sold this way, they are called batts , and they come in different thicknesses to match the depth of wall cavities, for example, approx. 5 inches to match a 2 x 6 inch wall cavity. Where rigid panels are most often used Some, such as EPS beadboard , are suitable for ground contact and are used against footings and exterior backfilled foundation walls. Against exterior exposed foundation walls should be coated to protect from sunlight . Against exterior walls between foundation and roof, installed between sheathing and siding. Either under ... insulating capacity into a small space. Important note 1 If you insulate the foundation with rigid panels, but you stop using rigid panels where the siding begins, then you should install flashing in between the bottom course of siding and the top edge of the rigid panels, to prevent water from seeping ... the rigid panels in two staggered layers, and fill the gaps at the seams with Thermal insulation ... insulating between the sheathing and siding, you should leave slight gaps between the rigid panels ... taped. Reduce heat conduction through the wall frame when used as sheathing. Rigid panels with a radiant ... the insulating gas, and the R value of the panel drops. Most rigid panels are made from crude oil ... use underground if conditions are relatively dry. Thermal insulation Rigid cellular polystyrene panels Rigid cellular polystyrene RCPS . This includes EPS, MEPS, XPS, beadboard, blueboard, and Styrofoam ... foam structure. Denser and more rigid than polystyrene panels, but more expensive. Must protect from ... used in Europe Lightweight wood fibre board. Cork material Cork More on rigid cellular polystyrene panels There are many types of rigid cellular polystyrene RCPS . Styrofoam is simply Dow Chemical ... more details
Refimprove date December 2009 A rigid frame in structural engineering is the load resisting skeleton constructed with straight or curved members interconnected by mostly rigid connections which resist movements induced at the joints of members. Its member can take bending moment,shear and axial loads. ref http triadmetalroof.com building systems rigid frame building.html ref ref http www.butlermfg.com about history.asp ref The two common assumptions as to the behavior of a building frame are 1 that its beams are free to rotate at their connections or 2 that it s members are so connected that the angles they make with each other do not change under load. Frame works with connections of intermediate stiffness will be intermediate between these two extremes. Frame works with connections of intermediate stiffness are commonly called semirigid frames. The AISC specifications recognize three basic frame types Rigid Frame, Simple Frame, and Partially Restrained Frame. ref cite book last Gaylord first Edwin title Steel Structures year 1992 publisher McGraw Hill, Inc location New York isbn 0 07 023054 4 pages 555 ref The AISC Steel Specification Commentary on Section B3 provides guidance for the classification of a connection in terms of its rigidity. The secant stiffness of the connection K sub s sub is taken as an index property of connection stiffness. Specifically, K sub s sub M sub s sub sub s sub where M sub s sub moment at service loads, kip in N mm sub s sub rotation at service loads, rads The secant stiffness of the connection is compared to the rotational stiffness of the connected member as follows, in which L and EI are the length and bending rigidity, respectively, of the beam. If K sub s sub L EI 20, it is acceptable to consider the connection to be fully restrained in other words, able to maintain the angles between members . If K sub s sub L EI 2, it is acceptable ... Chicago isbn 1 56424 060 6 pages 16.1 263 ref References reflist DEFAULTSORT Rigid Frame Category ... more details
The rigid rotor is a mechanical model that is used to explain rotating systems. An arbitrary rigid rotor is a 3 dimensional rigid object, such as a top . To orient such an object in space three angles are required. A special rigid rotor is the linear rotor which is a 2 dimensional object, requiring two ... classification of molecules . small The linear rotor The linear rigid rotor model consists of two ... masses and the values of the masses are the only characteristics of the rigid model. However, for many .... Corrections on the rigid model can be made to compensate for small variations in the distance. Even in such a case the rigid rotor model is a useful point of departure zeroth order model . The classical linear rigid rotor The classical linear rotor consists of two point masses math m 1 math and math ... is rigid if math R math is independent of time. The kinematics of a linear rigid rotor is usually ... rigid rotor is given by math 2T mu R 2 big dot theta 2 dot varphi , sin theta 2 big mu R 2 big ... Hamiltonian function of the linear rigid rotor is math H frac 1 2 mu R 2 left p 2 theta frac p 2 varphi sin 2 theta right . math The quantum mechanical linear rigid rotor The linear rigid rotor model ... quantum mechanics Hamiltonian operator. For the rigid rotor in a field free space, the energy ... moment integral. This constraint results in the observed selection rules for the rigid rotor math Delta m 0 quad hbox and quad Delta l pm 1 math Non rigid linear rotor The rigid rotor is commonly ... math The non rigid rotor is an acceptably accurate model for diatomic molecules but is still somewhat ... . Arbitrarily shaped rigid rotor An arbitrarily shaped rigid rotor is a rigid body of arbitrary shape ... that can be ignored . A rigid body can be partially characterized by the three eigenvalues of its ... classifies molecules seen as rigid rotors as follows spherical rotors symmetric rotors oblate symmetric ... moments of inertia. Coordinates of the rigid rotor Different branches of physics and engineering ... more details
In modal logic and the philosophy of language , a term is said to be a rigid designator or Kripkean soul when it designates picks out, denotes, refers to the same thing in all possible worlds in which that thing exists ref Oxford Dictionary of Philosophy, Revised Second Edition 2008, P318 ref and does not designate anything else in those possible worlds in which that thing does not exist. A designator is persistently rigid if it designates the same thing in every possible world in which that thing exists and designates nothing in all other possible worlds. A designator is obstinately rigid if it designates the same thing in every possible world, period, whether or not that thing exists in that world. Rigid designators are contrasted with non rigid or flaccid designator s , which may designate different things in different possible worlds. Proper Names and Definite Descriptions The notion of rigid designation was first introduced by Saul Kripke in the lectures that became Naming and Necessity , in the course of his argument against descriptivism descriptivist theories of reference, building on the work of Ruth Barcan Marcus . At the time of Kripke s lectures, the dominant theories of reference in Analytic philosophy associated with the theories of Gottlob Frege and Bertrand Russell held that the meaning of sentences involving proper names could be given by substituting a contextually appropriate description for the name. Russell, for example, famously held ref Russell, Bertrand, Knowledge by Acquaintance and Knowledge by Description, The Problems of Philosophy , chapter 5 http www.ditext.com russell rus5.html online text . ref that someone who had never met Otto von Bismarck ... rigid designation is a property of the way terms are used , not a property of the terms themselves ... need to recognize rigid uses of definite descriptions, and argued that Bertrand Russell Russell ... One interesting consequence of Kripke semantics is that identities involving rigid designators are necessary ... more details
Context date October 2009 Unreferenced date December 2011 File Function mode of a rigid needle adapter.jpg thumb 300px Function mode of a rigid needle adapter The concept of the rigid needle adapter makes possible a contacting of finest structures on printed and assembled circuit board and also direct contacting in fine pole connectors. For this concept one need every time a raster head and a rigid needle adapter. The spring probes are arranged in a compact wikt grid grid in the raster head so that up to 280 spring probes per square cm can be integrated. The rigid needles are moved to the desired contact point by the spring probes in the rigid needle adapter. Contacting pitch down to 150 m can be tested by the movement of the rigid needles. The contacting stroke is effected in the needle adapter. Contacting forces of 0.4 N to 1.5 N depending on the spring probe are exerted on the contacting point by the spring excursion of approximately 2.5 mm. Life cycle of rigid needle adapters The contacting tip of the rigid needle becomes blunt in time through contacting. The service life thus depends mainly on the material to be contacted. Under optimum conditions up to 500,000 contactings and more can be achieved with the rigid needles. Spring pins manufactured specifically for this application and the compact design mean that service lives of far more than 1 million contact cycles are possible in practice. Combination of spring probes and rigid needles File Combination of spring probes and rigid needles.jpg thumb 300px Combination of spring probes and rigid needles The rigid needle adapter is manufactured to customer requirements. Rigid needle adapters for very fine structures are called also MCA Micro Contacting Adapter . The feasibility matrix shows which spring pins can be combined with which rigid needles. The concept allows not only the contacting of assembled ... of rigid needle adapter fine pitch http www.microcontact.ch Microcontact AG Manufacturer of rigid ... more details
File RigiBelt Patent.jpg thumb right Patent Drawing for Serapid RigiBelt Rigid Belt Actuator 2007 . A rigid belt actuator , also known as a push pull belt actuator or zipper belt actuator , is a specialized mechanical linear actuator used in push pull and lift applications. The actuator is a Belt mechanical belt and pinion device that forms a telescoping beam or column member to transmit traction and thrust. Rigid belt actuators can move dynamic loads up to approximately 230 pounds over about 3 feet of travel. ref Serapid RigiBelt brochure http www.serapid.us PDF rigibelt the new non magnetic telescopic linear actuator.pdf ref Principle of operation Rigid belt actuators can be thought of as rack and pinion devices that use a flexible rack. Rigid belt actuators use two reinforced plastic Belt mechanical Ribbed belt ribbed belt s, that engage with pinions mounted on drive shafts within a housing. The belts have evenly spaced load bearing blocks on the non ribbed face. As the pinions spin, the belts are rotated 90 degrees through the housing, which interlocks the blocks like a zipper into a rigid linear form. The resulting beam or column is effective at resisting tension and compression buckling . Because the actuating member can fold on itself, it can be stored relatively compactly in a storage magazine, either in an overlapping or coiled arrangement. The actuator is driven by an electric motor. Development A rigid belt actuator is effectively a non metallic variation of the rigid chain actuator. But, while the interlocking chain actuator has been around since the middle of the 20th century, rigid belt technology didn t emerge until the new millennium. ref cite patent US 1925194 ref ref cite patent US 2554300 ref Jo l Bourc His received a patent for his Linear Belt Actuator in 2007. ref cite patent US 7270619 ref References Reflist See also Linear actuator Rigid chain actuator External links http serapid.us rigidbelt.html Serapid RigiBelt Category Actuators ... more details
Rigid gas permeable lenses are rigid contact lens es made of oxygen permeable polymers . Initially developed in the late 1970s, and through the 1980s and 1990s, they were an improvement over prior hard lenses that restricted oxygen transmission to the eye. Rigid lenses are able to replace the natural shape of the cornea with a new refracting surface. This means that a regular spherical rigid contact lens can provide good level of vision in people who have astigmatism or distorted corneal shapes as with keratoconus . However, they require a period of adaptation before full comfort is achieved. ref Terry et al., CLAO J 1986 15 305 ref References references External links commons Contact lens Do not add links to commercial organisations here. They will be removed. For more information, see Wikipedia s policy on external links at WP EL http keratoconusinfo.wordpress.com corneal lenses Use of rigid gas permeable lenses in Keratoconus Category Contact lenses eye stub ... more details
Orphan date February 2009 Image Ianalexanderthumb.jpg right frame Ian Alexander Rigid Airship Design B.V. was a company founded in the Netherlands in 1998 with the aim of building a modern rigid airship. In 1996, Scottish intellectual and airship expert Ian Alexander initiated a project in the Netherlands in co operation with the Technical University of Delft , to design and construct a modern classic rigid airship based on proven technology. The project involved leading Dutch companies RDM Aerospace N.V., Nevesbu designers of ships and submarines , Stork N.V. , and Fokker Aviation . Consortium Rigid Airship Design was established on 26 May 1998 but went bankrupt 1 August 2001. The initiative provoked series of discussions in the Estates General of the Netherlands Dutch Parliament and on governmental level. As a result Platform Luchtschepen Airship Platform was structured to investigate the attainability of projects like this in The Netherlands. The platform consists of representatives from governmental bodies, industry and environmental organisations. Results of the platform and the creative legacy of the Rigid Airship Design project are the cornerstones of a feasibility study on how to deploy a classic rigid airship to International Relief Organisations for rapid disaster relief after tsunamis, earthquakes and other calamities. External links http www.airship association.org Airship Association http rigid.tripod.com english.html Airship Holland http www.platformluchtschepen.nl Platform for Airships Category Defunct aircraft manufacturers of the Netherlands Category Airships ... more details
Unreferenced date February 2008 A Rigid framed power kite consists of a single skin and a rigid frame. They are often used in the popular sport of kite surfing. Typically it has four lines and a pair of handles or a particular style of bar, again with 4 lines. See also kite control systems The best known commercial kite of this type is the Peter Lynn C Quad. Category Kites kite stub ... more details
In mathematics , in the representation theory of Group mathematics group s, a finitely generated group is said to be representation rigid if for every math n math , it has only finitely many isomorphism classes of irreducible representation s of dimension math n math . External links http www.math.ou.edu amagid blmm.pdf The proalgebraic completion of rigid groups Category Properties of groups Category Representation theory of groups Abstract algebra stub ... more details
Multiple issues orphan September 2010 confusing April 2009 refimprove April 2009 The rigid band model assumes that the electronic density of states of an alloy can be inferred from that of the host. ref Cite journal doi 10.1007 BF02422513 title On rigid bands and mass enhancements in noble metal alloys year 1972 author Grimvall, G ran journal Zeitschrift f r Physik B volume 14 pages 101 bibcode 1972PKM....14..101G ref References Reflist Category Condensed matter physics Physics stub ... more details
File Rigid Chain Actuator.gif 300px right Rigid chain actuator. A rigid chain actuator , known variously as a linear chain actuator , push pull chain actuator , electric chain actuator or column forming chain actuator , is a specialized mechanical linear actuator used in window operating, push pull material ... telescoping member to transmit traction and thrust. High capacity rigid chain lifting columns ... LinkLift Rigid Chain Actuator 2001 . Rigid chain actuators function as rack and pinion linear actuators that use articulated racks. Rigid chain actuators use limited articulation chains, usually ... of the actuating member, the rigid chain , are articulated in a manner that they deflect from ... through the housing, which guides and locks the chain into a rigid linear form effective at resisting ... relatively compactly in a storage magazine, either in an overlapping or coiled arrangement. Rigid chain actuators are generally driven by electric motors. Most rigid chains are manufactured from ... Rigid Chain Actuator 1972 . Modified roller chain has been used extensively in material handling equipment ... of chain encapsulated in a guide channel . The development of efficient rigid chain actuators broadened the use of chain actuation for industrial applications. Small scale rigid chain ... ref Rigid chain actuators are also used as the lifting columns in performing arts facilities, incorporated in stage, orchestra and seating platform lift systems. Increasingly rigid chain systems are being ... distinction between types of rigid chain actuator is whether the actuating member is formed ... Rammer 1908 . Rigid chain actuators were developed from chain rammers that used a single ram chain thrust ... a century ago, his rammer still bears a strong resemblance to many modern rigid chain actuators ... are not common. References Reflist See also Linear actuator Rigid belt actuator External links http ... showing rigid chain actuation of a stage lift Category Actuators ... more details
Infobox Album See Wikipedia WikiProject Albums Name A Rigid Shard of Balance 1 Type EP Artist Polydream Cover Eppolydream.jpg Released July 14, 2006 Recorded 2005 2006 Genre Alternative rock , Shoegaze Length Label Tin Whisper Media Group Producer Polydream Reviews OnMilwaukee.com Rating 4.5 5 http www.onmilwaukee.com music soundcheck articles polydream.html link Rag Magazine Rating 4.5 5 http www.ragmagazine.com Past 20Issues 2007 RAG 20Magazine 20 20February 202007.pdf link Music Critic.ca Rating 3 5 http www.music critic.ca wp 2007 polydream rigid shard of balance link Last album This album A Rigid Shard of Balance 1 br 2006 Next album Send Me to the Sun br 2007 A Rigid Shard of Balance 1 is an EP by the United States American alternative rock band Polydream , released on July 14, 2006. It is a prelude to the band s debut full length album, titled Send Me to the Sun . Track listing Catch Me If You Can Juner Everything Else Comes to Life Catch Me If You Can Giddings Love for Who Remix Got a Good Feeling Live in Studio DEFAULTSORT Rigid Shard Of Balance Category Polydream albums Category 2006 EPs 2000s alt rock album stub ... more details
Image Nobile norge.jpg 300px thumb right Explorer Roald Amundsen crossed the North Pole in the semi rigid airship Norge airship Norge in 1926. Semi rigid airships are airship s with a partial framework. These often consist of a rigid, or occasionally, flexible, keel frame along the long axis under the aerodynamic ... with the other parts of the ship, semi rigid construction was able to achieve improvements in weight, aerodynamic, and structural performance. The boundary between semi rigid and non rigid airship s is vague ... or a proper structural keel. As in non rigid airships, the hull s aerodynamic shape is maintained ... pdfarchive view 1922 1922 20 200049.html Semi Rigid v. Rigid Airships FLIGHT , January 22nd 1922 ref History In the first decade of the twentieth century, semi rigid airships were considered more suitable for military use because, unlike rigid airship s, they could be deflated, stored and transported ... or of the semi rigid sort, because experience on the Continent has proven that for military service the rigid type, exampled more particularly by the Zeppelin school, cannot be collapsed .... ref Non rigid airships had a limited lifting capacity due to the strength limitations of the envelope ... first ship flying in 1907. It had a rigid keel under the envelope. Four more military ... Basenach last accessed 2008 07 05 ref The most advanced construction of semi rigid airships interbellum ... most well known member, and he designed and flew several semi rigid airships, including the Norge airship ... , for the Soviet Union s Russian airships airship program . List of other semi rigid airships Pre ..., Le Jaune Ascending From the Meadows of Moisson, France ref Lebaudy built many other semi rigid airships ... semi rigid airship to serve with United States Navy . RS 1 was the only semi rigid American military ... developments As of 2008 the only flying manned semi rigid airship is the Zeppelin NT . It comprises ... Cargolifter Joey was a small semi rigid experimental airship produced to test the design ref name at See ... more details
Unreferenced date December 2009 In the philosophy of language and modal logic , a non rigid designator or flaccid designator is a term that does not extensionally refer to the same object in all possible worlds . For example, consider the phrase The 43rd president of the United States of America while the 43rd president of the United States is actually George W. Bush , if things had been different, it might have been Al Gore or Ralph Nader instead. How remote these possible worlds are from the actual world is a discussion for many worlds interpretation physics and counterfactual ism. Non rigid designators are defined by contrast with Saul Kripke s notion of a rigid designator , which pick out the same thing uniquely in every possible world while there are possible worlds in which the 43rd president of the United States is Al Gore instead of George W. Bush, there are no possible worlds where George W. Bush is anyone other than the man who, in fact, he is. There are worlds where some person other than George W. Bush is named George W. Bush, but that s neither here nor there. Kripke uses this apparent asymmetry to argue in Naming and Necessity that no definite description which can designate non rigidly can be the meaning of a proper name . It is worth noting that some philosophers, such as Gareth Evans philosopher Gareth Evans have expressed doubt as to whether non rigid expressions ought to be called designators at all. See also rigid designator . DEFAULTSORT Non Rigid Designator Category Concepts in logic Category Modal logic Category Philosophy of language Category Names Category Reference ... more details
Refimprove date June 2010 The rigid buoyant boat RBB is a light weight but high performance and high capacity boat . Based on the concept of a Rigid hulled inflatable boat RHIB , it has a tube sponson manufactured from a solid material such as moulded polyethylene or aluminium and therefore being much more robust than the fabrics commonly used. Boats with foam filled collars such as the secure all around flotation equipped SAFE boats ref http www.safeboats.com safeboats.com ref employed by the US Coast Guard can also be classified as Rigid Buoyant Boats rather than true RHIBs as the collar is solid foam rather than inflated. The handling tends to be very similar to a RHIB likewise they will remain afloat buoyant even if completely flooded. Aluminium RBBs tend to be bespoke custom made to specification or low volume products whilst the tooling cost of rotomold ed polyethylene boats tends to require these to be higher volume products. At least three manufacturers are producing rotomolded boats of this type. ref http www.atlanticfocus.co.uk atlanticfocus.co.uk ref ref name marinerev http www.marinerevolution.com marinerevolution.com ref ref http www.pioneerboats.com pioneerboats.com ref One supplier has demonstrated the robustness of the boats by dropping one from a crane onto a concrete car park. ref name marinerev The U.S. Navy s small unit riverine craft and the Coast Guard s USCG Defender class boat Defender class convert 25 ft m sing on boat s are examples of RBBs. gallery File US Navy 070910 N 6639M 043 Sailors assigned to Riverine Squadron RIVRON 2 come ashore with two simulated detainees to be turned over to Mobile Security Squadron 3, Det. 33, during COMET 2007.jpg A 38 ft 12 m Rigid Buoyant Boat RBB , small unit riverine craft of the US Navy Image Rnli rbbs on thames at london.jpg RNLI RBBs at Lifeboat Pier, River Thames , London gallery See also Rigid hulled inflatable boat References Reflist Category Boat types sv Rigid buoyant boat ... more details
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