Kinematic Connection Research Articles

An 40Ar/39Ar thermochronology of the Ofoten‐Troms region: Implications for terrane amalgamation and extensional collapse of the northern Scandinavian Caledonides

Fifteen 40Ar/39Ar cooling ages are reported for metamorphic hornblende and muscovite from far traveled terranes constituting the Ofoten nappe stack of northern Norway. Eight cooling ages on hornblende range from 425 to 394 Ma and seven muscovite ages, from the same or nearby outcrops as the hornblendes, range from 400 to 373 Ma. These data are compared with 40Ar/39Ar ages from over a large part of the northern Caledonides to evaluate regional mineral cooling patterns. Results indicate that (1) Scandian (Silurian‐Devonian) metamorphism was predominant; (2) most of the nappes investigated contain some vestige of pre‐Scandian tectonism and/or metamorphism; (3) hornblende and muscovite cooling ages are progressively younger to the west and south, which suggests a hinged‐to‐the‐east mineral cooling pattern; and (4) a late, out‐of‐sequence thrust is the only disruption of this cooling pattern. Synmetamorphic amalgamation of the nappes resulted from Scandian A type subduction. The hinged‐to‐the‐east mineral cooling pattern implies isostatic adjustment and exhumation of the footwall of a west dipping, crustal‐scale extensional fault, located somewhere west of the present Norwegian coast, during late synorogenic gravitational collapse. The late out‐of‐sequence fault formed contemporaneously with uplift in the hinterland, implying a kinematic and temporal connection with east directed contractional faulting in the foreland.

Discovery of Neutral Hydrogen Associated with the Diffuse Shells of NGC 5128 (Centaurus A)

In this Letter, we present for the first time images and kinematics of neutral hydrogen, which is unambiguously associated with the optical shells of an E/SO galaxy, NGC 5128. Using the VLA, we have mapped diffuse H I (21 cm) emission out to approximately 15 kpc (15') from the nucleus of the galaxy to a limiting column density of 10(20) cm-2. These observations reveal the presence of 1.5 x 10(8) M. of H I, 10'-15' NE, N, and SW of the galaxy. The H I distribution follows the curvature of the outermost ''diffuse'' shells, and is slightly displaced, shifted 1' to the outside of the shells. The H I shows a smooth gradient in velocity over approximately 450 km s-1, nearly the same line-of-sight velocity range observed in the dust lane. Our results suggest that the H I might be a partial ring, rotating with the same sense as the main body of the galaxy. We discuss merger, accretion, and internal shell formation models and describe how the observed properties of the H I challenge existing theories of shell formation. We also find a morphological and kinematical connection between the NE cloud of H I and the outer optical filaments of Cen A, identifying the H I as the source of gas being ionized. Finally, we discuss the implications of these results on the study of high-z radio galaxies with extended emission-line regions.

Mixing and chemical reactions a tutorial

The objective of this paper is to complement previous reviews focusing on somewhat more classical aspects of mixing in the content of chemical reaction engineering and to provide additional fluid mechanical perspective by highlighting recent developments. Coverage is restricted to frameworks capable of accommodating a visual and physical description of fluid flow and associated spatial inhomogeneities that might ultimately lead to predictions in a variety of situations, in both laminar and turbulent flows. It is argued that the treatment of laminar or viscous mixing is in good shape. This has been spurred by theoretical developments based on chaos theory and increased computational resources, as well as by advances in fluid mechanics and a host of new experimental results; in this case a body of theory fulfills the double role of producing basic understanding leading to prediction. By contrast, the picture in turbulent mixing is still less sharply defined and no accepted paradigm fulfills both the role of understanding and engineering prediction. Typical flows undergo transitions and are, in general, far from homogeneous, involving coexistence of regions of active and poor mixing; current statistical approaches are not fully equipped to deal with these situations. The difficulty lies in the case of moderate and fast reactions. If reactions are diffusion controlled, chemistry is controlled by the smallest scales. Important processes occur within striations, and straightforward averaging, in general, does not work; coarse graining results in loss of interface and computing the rate of reaction cannot be accomplished without some sort of subgrid model based on the physics of the problem. A lamellar model provides a simple picture that frequently leads to accurate predictions and indicates when mixing effects are important. Noteworthy among recent developments are the observations of lamellar structures at Kolmogorov scales in highly turbulent flows and the establishment of the kinematical connection between chaos and mixing. Remarkably, the smallest scales in turbulent flows and chaotic flows appear to be described by identical statistics. Illustrations are provided throughout.

Simple Friction Model for Scissor‐Type Mobile Structures

Mobile or articulated structures have kinematic connections that permit large relative displacements between components that undergo small elastic deformations. Deployable structures are one example. They can be stored in a compact, folded configuration and can be deployed into a load‐bearing, open form by simple articulation. The deployable structures investigated in this paper are assemblages of basic units consisting of two straight bars connected to each other by a pivot that are called scissor‐like elements. These structures are stress free and stable in both their folded and deployed configurations, but exhibit a geometrically nonlinear behavior during deployment and dismantling. This behavior is influenced significantly by friction between the bars of each scissor‐like element as they experience a relative rotation about the pivotal connection. Because of the highly nonlinear nature of the structural response, modeling of the problem with contact‐type finite elements is not only very expensive, but also of doubtful convergence. Therefore, a simple model is proposed, based on simulating the effect of friction by adding nonlinear rotational springs at the pivotal connections. Numerical results obtained from this model were found to be in very good agreement with experimental measurements.

Active Faulting in the Southwestern Venezuelan Andes and Colombia Borderland

In the southern Andes, the Bocono fault shows a progressive disactivation of its right lateral movement, resulting from its attenuation against the transversal system of Bramon and its kinematic connection to the [open quotes]Pamplona indenter,[close quotes] considered as a part of the plate boundary between the Caribbean and South America. Near the Colombian frontier, the velocity of Bocono fault is probably less than 1 mm/yr. Such a decrease is explained because an increasing amount of the 1 cm/yr slip movement of the northern part of the fault is absorbed through a complex branching of the active trace, southwest Merida. Another significative amount of the rate movement of Bocono fault, considered as plate boundary, results absorbed by subparallel active faulting systems located to the east (Uribante and Caparo Systems) and to the west sides (San Simon-Seboruco, and San Pedro-Aguas Calientes-La Don Juana systems). The last system, extending beyond the frontier, shows a particular seimotectonic importance, as a probable source of the 1875 Cucata earthquake. In this way, the weight of the southwestern end of Bocono fault as a seismic source loses importance respect to the northern segment located between la Grita and Merida where the 1610 and 1894 earthquakes occurred, andmore » also as compared to the faults that define the [open quotes]Pamplona indenter[close quotes] like probable source for several other destructive earthquakes.« less

Primary Workspace of Industrial Robots With Roll-Pitch-Yaw Wrists

This paper presents a new method to identify the primary workspace of six-link industrial robots with Roll-Pitch-Yaw wrists in conjunction with four basic types of regional structures: the Cartesian, the cylindrical, the spherical and the articulated. The approach is to divide a robot into two subsystems, the regional structure and the wrist. Each subsystem is studied independently and then reassembled via a vector field analysis. Geometrical criteria are established to determine whether or not the kinematic connection between the wrist and the regional structure is valid. Conditions for a robot to access a point from a specified direction are derived first. The primary workpoints are then identified. Consequently, the boundaries of the primary workspaces (on the conservative side) of robots with Roll-Pitch-Yaw wrists, for the first time, can be analytically drawn. Some regional structures adopted in commercial robots which differ slightly from the standard ones are also included.

Late Cenozoic strike‐slip faulting in the Mojave Desert, California

Recent tectonic models for southern California treat the entire Mojave Desert Block as the site of distributed simple shear during late Cenozoic time. These models consider that much of the region is composed of a series of narrow blocks, bounded by active NW striking, right‐slip faults that have facilitated the distortion and rotation of the region about vertical axes during translations. As much as 100 km of cumulative right slip is predicted for these faults by some of these models. These kinematic models require that the faults of the Mojave Desert Block merge with the Garlock fault, which is viewed as the intact northern boundary that served to accommodate the distortion of the Mojave Desert Block by simple shear. Map‐scale structural relations are used to test explicit and implicit features of kinematic models proposed for the region. These relationships indicate that late Cenozoic NW striking, right‐slip faults of the Mojave Desert Block possess the following characteristics: (1) the faults are discontinuous, with only the Calico‐Blackwater fault spanning the entire Mojave Desert; (2) the faults terminate before reaching the Garlock fault; (3) faults south of an irregular line extending from near Barstow eastward to Ludlow and to Soda Lake are continuous and well developed and have a cumulative net slip of >40 km, whereas faults to the north are discontinuous and display <12 km of right slip; and (4) there is a northwestward decrease in net slip along most of the faults. A new kinematic model is proposed to reconcile these new observations with existing data. We assert that integrated strain within the province since middle Miocene time is not regionally homogeneous as predicted by simple shear models but is instead partitioned into six major domains. The domains probably have deformed and rotated about vertical axes independently of each other and are separated by zones of shortening or extension or by strike‐slip faults. Strike‐slip faults and folding have likely accommodated internal deformation and rotation of some of the domains. The model predicts that the Mojave Desert has been the site of ∼65 km of right shear since middle Miocene time. The broad network of faults of the Mojave Desert Block along with similar strike‐slip faults of the Death Valley region constitute a regional zone of right shear, named here, the Eastern California shear zone. Because of its probable physical connection to the San Andreas fault system, the Eastern California shear zone may have accommodated a significant portion of Pacific‐North American transform motion. The Eastern California shear zone accounts for 9–14% of the total shear, predicted from plate tectonic reconstructions, along the Pacific‐North American transform boundary since ∼10.6 Ma. The kinematic connection of the normal faults of the Death Valley region, with the San Andreas fault system via the faults of the Mojave Desert accords with the deduction of Atwater (1970) that late Cenozoic extension in portions of the Basin and Range province is related to Pacific‐North American transform shear. Finally, the present arcuate trace of the Garlock fault is ascribed to oroclinal folding within the broad zone of distributed shear of the Eastern California shear zone.

A soluble nonlinear bose field as a dynamical manifestation of symmetric group characters and young diagrams

A model of quantum nonlinear wave interaction is solved algebraically. While the hamiltonian has no kinematical connection with the symmetric group S n , the eigenstates are expressed in terms of symmetric group characters as quantum realizations of Schur functions i.e. Young diagrams. Class multiplication of S n is embedded in the dynamics.

Dynamics of Articulated Structures. Part I. Theory

ABSTRACT A finite element based method is developed for geometrically nonlinear dynamic analysis of spatial articulated structures; i.e., structures in which kinematic connections permit large relative displacement between components that undergo small elastic deformation. Vibration and static correction modes are used to account for linear elastic deformation of components. Kinematic constraints between components are used to define boundary conditions for vibration analysis and loads for static correction mode analysis. Constraint equations between flexible bodies are derived in a systematic way and a Lagrange multiplier formulation is used to generate the coupled large displacement-small deformation equations of motion. A lumped mass finite element structural analysis formulation is used to generate deformation modes. An intermediate-processor is used to calculate time-independent terms in the equations of motion and to generate input data for a large-scale dynamic analysis code that includes coupled e...

Non-linear problems of connecting composite spatial bodies and thin shells, and variational methods for their solution

The contact formulation of geometrically non-linear problems of connecting composite spatial bodies, as well as thin composite shells interconnected by a butt (rigidly or not, as a hinge, say) is considered. In this formulation, the composite body (shell) is separated into individual elements, appropriate interaction reactions are introduced into the consideration on the common interface, and an appropriate boundary value problem is formulated for each element. An artificial increase in the number of unknowns of the problem here results in a corresponding increase, in the number of equations because of the replacement of the static connection conditions for the elements by double the number of static boundary conditions on the common interface. While solving the problem, the interaction reactions are determined from the kinematic conditions for the element connections. It is shown that the advantage of such a formulation for problems of the connection of composite bodies is the considerable simplification of the application of methods of the direct calculus of variations for their solution. To this end, functionals referred to the class of generalized Lagrange functions for problems defined on discontinuous stress, deformation, and displacement fields /1–3/, to which the unknown interaction reactions are also referred together with the displacements to the number of functional arguments, are constructed for spatial composite bodies and composite shells. It is proved that the conditions for their stationarity yield variational equations from which static boundary conditions equivalent to the static connection conditions, and kinematic connection conditions follow in addition to the equilibrium equations and the static boundary conditions on the boundaries where the external static forces are given. According to these equations, the use of direct methods for solving the problems does not require the construction of coordinate functions for the displacements with preliminary satisfaction of the kinematic connection conditions.

Spherically-symmetric shock wave in a dilatant medium

Abstract The problem is examined of the expansion of a spherical region filled with a gas with high initial pressure, in a continuous medium with dilatancy, by which is meant the kinematic connection between the velocities of the dilatational and the maximal tangential deformations. The change in the medium's density behind the shock wave's front takes place only due to this kinematic connection. The model given was examined in a number of papers (/1–3/ and others) mainly for describing the behavior of certain soils in an underground explosion. Previously the soil density behind the shock wave's front had been reckoned to be constant /4–6/. An analogous problem is examined below in the case when the dilatancy velocity coefficient is a piecewise-constant function of the medium's density.

New look at the Ptolemaic system

The Ptolemaic system of planetary motions is examined in detail in order to demonstrate its direct kinematical connection with a heliocentric system. Ptolemy’s planetary parameters are shown to be in good agreement, upon transformation, with modern values.

Dynamics of an elastic ellipsoid

The present investigation is an attempt to provide a dynamical basis for the kinematical scheme employed previously for the empirical correlation of certain nuclear data. The primary purpose of this paper is the delineation of the dynamical system itself. Particular attention is paid to the following points: 1) The basic assumptions required for the specification of the system. These may be divided roughly into two groups, those employed in the definition of the independent degrees of freedom chosen for the description of the system and those required for at least partial characterization of relevant potentials. The former are of principal importance in the formulation of the kinetic energy operators appropriate to the choice of degrees of freedom and are dealt with in detail. The latter, being less germane to the purpose of this paper, are treated more or less summarily. 2) The detailed development of the kinetic energy of this model. It is carried out without approximation ;i.e., the formulation of this aspect of the physical implications of the model is quite rigorous. Calculations within the model must ultimately, of course, require resort to approximation. 3) The physical significance of two different representations employable for partial diagonalization of the Hamiltonian. 4) The close kinematical connection between the system considered herein and the hydrodynamical model. 5) The extent to which the dynamical system incorporates the kinematical scheme previously used for data correlation. Directions of feasible, and perhaps fruitful, generalization are indicated with the suggestion of possibly significant implications for the description of nuclear collective behavior in regions in which neither purely vibrational nor purely rotational characteristics are to be expected.

Kinematic connections and their application to physics

Kinematic connections and their application to physics

The “Indumor”: A kinematic device which indicates the performance of a polyphase induction machine

A kinematic device is described and illustrated which represents the vector diagram of a polyphase induction machine. The parts are made to assume at will different positions corresponding to different loads of an induction motor or generator. The primary and the secondary constants, the magnetizing current, and the core loss, are also adjustable at will. The device permits the visualization of the performance of an induction machine and can be used for a study of a given machine or for a selection of the constants to give the desired performance characteristics of a new machine. The input, output, torque, speed, power factor, etc., can be read off on the device as in an actual brake test. The kinematic connections consist mainly of generalized proportional dividers and of parallel tongs, so combined as to satisfy a system of simultaneous vectorial equations which represent the properties of the machine. Further applications of the device to polyphase commutator motors are suggested.

The ``Indumor'' A Kinematic Device which Indicates the Performance of a Polyphase Induction Machine

A kinematic device is described and illustrated which represents the vector diagram of a polyphase induction machine. The parts are made to assume at will different positions corresponding to different loads of an induction motor or generator. The primary and the secondary constants, the magnetizing current, and the core loss, are also adjustable at will. The device permits the visualization of the performance of an induction machine and can be used for a study of a given machine or for a selection of the constants to give the desired performance characteristics of a new machine. The input, output, torque, speed, power factor, etc., can be read off on the device as in an actual brake test. The kinematic connections consist mainly of generalized proportional dividers and of parallel tongs, so combined as to satisfy a system of simultaneous vectorial equations which represent the properties of the machine. Further applications of the device to polyphase commutator motors are suggested.