Fundamental Motion Research Articles

Alignment processes in a smectogenic side‐chain liquid‐crystal copolymer

AbstractThe dielectric properties of the siloxane side‐chain liquid‐crystal (LC) copolymer 1 were investigated using high‐frequency techniques. The copolymer could be aligned homeotropically either by cooling from the melt with the aligning electric field on or by application of the field whilst the sample was in the LC state. Using the latter method the kinetics of the homeotropic alignment process could be determined. Samples of different purity were used and the kinetics and steady‐state properties compared and a strong dependence on polymer purity was found in both cases. Fuoss‐Kirkwood deconvolution of the relaxation peaks allowed examination of the fundamental motion of the mesogenic units.

Numerical effects of gravitational light deflection on the determination of the equinox and equator

Observations of the sun and major and minor planets made by transit circle telescopes are used to determine positions of the equinox and the celestial equator and, by repeated observing programs, the motions of these fiducial references. Long series of such absolute observations, when combined into catalogs such as the FK5, yield a fundamental coordinate system which is an observational approximation to an ideal, dynamically defined coordinate system. In such a system the equinox, for example, is defined implicitly by the right ascensions (at mean epoch) and the proper motions of the stars included in the catalog system, together with the adopted constant of precession. It may be noted that independent, highly accurate determinations of the latter quantity thus help to improve the fundamental proper motion system.

A basic study of the automated generation of machine structures. 1st report Graphical description of the functional structure of machines.

As a basic study for the establishment of the methodology for computer aided or automated design of machine structures, this report deals with the method of graphical description of the functional structures of power transmitting or motion transmitting machines, such as machine tools, measuring apparatuses, etc. The machines are considered as the aggregation of motion transmitting elements, such as gear mechanism, screw driving mechanism, can mechanism, etc. and their functional structures are graphically described using these elements. In this topological graph, the nodes correspond to motion transmitting elements and the edges correspond to relative relation between two elements such as fixed, sliding or motion transmitting. In addition, two fundamental motions, which are the input and output motions of the element are attached to each node. A gear slotter is taken as an example of graphical description of machine structure, and its fundamental motion graph and basic graph are presented.

Force field calculation of the in-plane fundamental motions of tellurophene and selenophene

A valence force field has been derived for the 8A1 and 7B1 in-plane vibrations of selenophene and tellurophene. The force constants' refinement has been derived from experimental frequencies previously obtained for selenophene and tellurophene. Numerical values of the force constants show that there is a noticeable variation in the ring-aromaticity of these congeners, going from thiophene to tellurophene, as previously established by different techniques.

REINVESTIGATION OF O, B STAR KINEMATICS AND DETERMINATION OF CORRECTIONS TO PRECESSION

Radial velocities, distances and proper motions of 1412 early-type stars are used for in-vestigation and analysis of the galactic kinematics in the solar neighbourhood. It is shownfrom the results obtained here that differences among the components (uo, vo) of meanmotions relative to the Sun of early-type stars with different heliocentric distances are sig-nificant. This phenomenon can be reasonably explained by the three-star drift hypothesis,and thus the conventional Local Standard of Rest is likely to be moving outwards at 25 km/s.The Oort constants A and B and the parameters C and D connected with radial motion ofthe Galaxy that are obtained from the present investigation are (A, B)=(16.6±0.6, -14.4±1.7) km/s/kpe and (C, D)=(0.5±0.5, -2.0 ±0.4) km/s/kpe, respectively, which are invery satisfactory agreement with corresponding values of these parameters gained before. Thedetermined precession corrections, which are based on the kinematic parameters found fromsolution and data of fundamental proper motions of stars, are quite accurate: (△n, △k)=(0.″56 ± 0.″04, -0.″33 ± 0.″05) per century. The found △n, △k fully coincide with previouscorresponding values obtained by some authors.

Subharmonic and Chaotic Motions of Compliant Offshore Structures and Articulated Mooring Towers

Compliant offshore structures have complex nonlinear dynamics. Subharmonic resonances can co-exist with small fundamental motions. To prevent a simulation missing an entire subharmonic peak, a comprehensive set of initial conditions must be explored. Chaotic nonperiodic motions can also arise in deterministic problems. These are extremely sensitive to starting conditions and require a statistical description. Chaotic responses and their adjacent subharmonics of arbitrarily high order mean that the duration of digital, analogue and laboratory simulations must be chosen with considerable care. Resonances of articulated mooring towers, encountered in tank tests, are used to illustrate these general concepts.

Measurement of the high frequency piezoelectric strain response of polarized PVDF

Abstract Heterodyne interferometer displacement measurements were made of the responsive motions of 600 μm thick PVDF piezo-film. The thickness mode response to a 230 volt pulse was monitored both optically (inverse effect) and electrically (indirect effect). Also observed were the fundamental motions excited by the application of a ±15 volt continuous wave. Mechanical damping coefficients and values of d33 were inferred from observations of thickness displacements excited by the transient voltage pulse and by fitting data to an electro-mechanical model of the piezo-polymer.

The mixing layer: deterministic models of a turbulent flow. Part 1. Introduction and the two-dimensional flow

The prevalence in a turbulent mixing layer of dynamical events with a coherent history over substantial times suggests that it is profitable to study in detail entirely deterministic versions of this flow and to attempt to use a simplified synthesis of these solutions as the fundamental representation in a stochastic treatment of the layer. It is proposed that the deterministic representation of the flow be achieved by the embedding of a short hierarchy of motions which are studied in detail, though not exhaustively, in Parts 1, 2 and 3. Part 1 deals with the fundamental or first-order motion, which is the evolution of a layer constrained to be purely two-dimensional.

Reliable indirect labor standards achieved through computerized computation of mean slot values of the gamma distribution

Abstract The importance of reasonably accurate (within ± 10%) indirect labor standards is recognized by the vast majority of practicing industrial engineers. Traditional work measurement methodologies including stopwatch study, standard data, and fundamental motion data can do the job, but these techniques are often not cost effective because of the time required to develop fair standards in advance of the work being done. Slotting methods such as used in the technique referred to as “Universal Indirect Labor Standards” allow the relatively rapid assignment of standards in a very short time. A method of developing Universal Indirect Labor Standards that will give satisfactory results is to slot a sample of benchmark jobs in the form of the gamma distribution. The value of each slot is computed by calculating the expected value (mean) of the gamma distribution that characterizes each slot. The computer is an effective tool to make these laborious computation and arrive at good universal standard values for each slot in the distribution characterized by the benchmark jobs.

Estimating the law of randomly moving particles by counting

The fluctuation of the counts of particles inmregions are used to yield an estimate of a fundamental motion parameter. The effect of varyingmon the precision of the estimation method is considered. An exact analysis and simulation of the Fürth pedestrian vector process is presented.

Estimating the law of randomly moving particles by counting

The fluctuation of the counts of particles inmregions are used to yield an estimate of a fundamental motion parameter. The effect of varyingmon the precision of the estimation method is considered. An exact analysis and simulation of the Fürth pedestrian vector process is presented.

Laser Raman Spectrum of Cyclic Diglycine

In our earlier researches we have reported the normal vibrations of glycine and its oligomers and cyclic tetraglycine. Structure, infrared spectra, and normal vibration analysis of cyclic diglycine (CDG) have also attracted considerable attention in the literature because of the biological importance of CDG. Although the infrared active Au and Bu fundamental vibrations have been studied extensively, the Raman active Ag and Bg motions have not been reported so far. Recently the Raman active motions have been predicted on the basis of normal coordinate analysis employing Urey-Bradley force field. We thought it worthwhile to record the Raman spectrum of CDG (1) to weigh the applicability of normal coordinate analysis technique in predicting the Ag and Bg fundamental motions of CDG and (2) to substantiate the assignment of these motions on the basis of our observed Raman spectrum.

Vortex perturbations of the nonstationary motion of a liquid with a free boundary

The first studies on the stability of nonstationary motions of a liquid with a free boundary were published relatively recently [1–4]. Investigations were conducted concerning the stability of flow in a spherical cavity [1, 2], a spherical shell [3], a strip, and an annulus of an ideal liquid. In these studies both the fundamental motion and the perturbed motion were assumed to be potential flow. Changing to Lagrangian coordinates considerably simplified the solution of the problem. Ovsyannikov [5], using Lagrangian coordinates, obtained equations for small potential perturbations of an arbitrary potential flow. The resulting equations were used for solving typical examples which showed the degree of difficulty involved in the investigation of the stability of nonstationary motions [5–8]. In all of these studies the stability was characterized by the deviation of the free boundary from its unperturbed state, i.e., by the normal component of the perturbation vector. In the present study we obtain general equations for small perturbations of the nonstationary flow of a liquid with a free boundary in Lagrangian coordinates. We find a simple expression for the normal component of the perturbation vector. In the case of potential mass forces the resulting system reduces to a single equation for some scalar function with an evolutionary condition on the free boundary. We prove an existence and uniqueness theorem for the solution, and, in particular, we answer the question of whether the linear problem concerning small potential perturbations which was formulated in [5] is correct. We investigate two examples for stability: a) the stretching of a strip and b) the compression of a circular cylinder with the condition that the initial perturbation is not of potential type.

Infrared spectrum and vibrational assignment of π-allyltricarbonylcobalt

Summary The infrared spectrum of π-allyltricarbonylcobalt has been recorded between 4000 and 300 cm −1 . The assignment of fundamental motions was essentially based on the crystal spectra in polarized light. The observed absorption pattern in the solid state seems to indicate that the molecule crystallizes in the monoclinic P m or C m space groups.

Developments in seismometry

Seismometers are instruments for measuring the motion of the earth's surface with respect to an inertial frame. The spectrum of earth motion is discussed and the development of seismometers reviewed with emphasis on the types currently used. Improvements in displacement transducers have permitted the development of wide-band devices, employing a much smaller inertial mass than was previously thought possible, and sensitivities close to fundamental Brownian motion have been achieved. It is concluded that future developments in seismometry will involve miniature wide-band instruments employing negative feedback to maintain the position of the mass and ensure long-term stability. Strainmeters, in which the distance between two piers in the earth is compared with a standard length, are also reviewed and their future development thought to lie in tensioned-wire instruments, where large numbers are required for detailed short period studies, and in laser-interferometric instruments for the study of long-term strain.

Stellar proper motions with reference to galaxies

While fundamental proper motions are affected by errors in precession, the proper motions with reference to galaxies are free from this effect and should serve better for research in stellar astronomy. Three programs are in progress at present: Lick, Russia and Yale-Columbia. There is a serious disagreement between the first results from the Lick and Russian programs; the cause of these disagreements is not yet known. Further progress is expected to explain these discrepancies and to contribute to knowledge of the structure of our Galaxy.

Rayleigh waves at a continental boundary by the finite element method

The finite element method in two dimensions must be modified for the study of Rayleigh waves in an oceanic model as follows. Horizontal displacements within finite elements of water must be found from vertical displacements and the condition of irrotational motion. This method leads to a discontinuity in horizontal displacement at the ocean bottom. It gave phase velocities of Rayleigh waves in the region of the Pacific ocean-bottom seismometer which agreed to within 0.2 per cent with those found by the method of Haskell and Dorman. It also gave the variation with depth of the horizontal and vertical amplitudes of the propagating Rayleigh modes. For fundamental Rayleigh-mode motion at a period of 21.33 sec incident on either side of a model of the region between the Pacific ocean-bottom seismometer and Berkeley, 96 per cent of the incident energy is transmitted as the fundamental Rayleigh mode. This result is quite different from that for the propagation of the fundamental Love mode. At a period of 21.33 sec, the fundamental Rayleigh mode has a horizontal amplitude at the ocean bottom of only a little over one-half that of the fundamental Rayleigh mode in the region of Berkeley, even for Rayleigh waves approaching from the west. This corresponds to a difference of 0.2 in estimates of surface-wave magnitude.

The propagation of Love waves across nonhorizontally layered structures

abstract A finite element technique is developed to study the propagation of Love waves across nonhorizontally-layered structures. A half-space is approximated by a rigid base at great depth. Previous results of other authors are confirmed. Detailed models of a continental boundary and of a structure including a slab of lithosphere dipping downard at an angle of 45° are analyzed. For incident fundamental Love-mode motion, at a period of 25 sec, on either side of the model of a continental boundary, the total energy in all of the reflected modes is found to be less than 0.1 percent of the incident energy, while the energy in the transmitted higher modes is 48 percent of the incident energy. These results are strikingly different from the results for previous models of a continental boundary. For incident fundamental Love-mode motion, at a period of 25 sec, on the “oceanic” side of the model including the dipping slab, the total energy in the reflected modes is found to be approximately 1 percent of the incident energy, and that in the transmitted higher modes, 36 per cent of the incident energy. For incident fundamental Love-mode motion, at a period of 25 sec, on the “shallow sea” side of the model including the dipping slab, the total energy in the reflected modes is found to be approximately 3 percent of the incident energy, and that in the transmitted higher modes, 34 percent of the incident energy.

On Determination of Correction to Precession from Stellar Proper Motions

view Abstract Citations (23) References (6) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On Determination of Correction to Precession from Stellar Proper Motions Vasilevskis, S. ; Klemola, A. R. Abstract Recent values for correction to centennial precession, with their mean errors, derived by Fricke (1967) from fundamental proper motions are: Ap1=+1'.'10 +0.15 and AX+Ae=+1'.'20 +0.16, as a consequence of the directly determined An +0.44 +0'.'06 and Ak = -0:19+0:07. Proper motions with reference to galaxies, derived at Lick and compared with those in AGK3, yield An= +0:31+007 and Ak = -0' 78 +0 .09. The disagreement between both sets, particularly for Ak, can be explained either by systematic errors in the Lick proper motions or by local star streamings that vitiate the correction to precession derived from the fundamental proper motions. Although at present there is no evidence of systematic errors in proper motions measured at Lick, a more definite conclusion must await the future progress of the Lick program, only 7% of which has been completed up to date. Publication: The Astronomical Journal Pub Date: August 1971 DOI: 10.1086/111154 Bibcode: 1971AJ.....76..508V full text sources ADS |

Waves in Nonlinear Lattice

In this article waves in nonlinear lattice or in nonlinear medium are studied. One of the aims is to seek for the point of view to deal with the great majority of phenomena related to nonlinear waves in general. For one dimensional nonlinear lattice analytic and computer-experimental treatments have been developed. It has been found that a certain kind of pulse-like waves (solitons) is the fundamental motion in nonlinear lattice vibration. If two or more solitons collide, they interact nonlinearly, pass through one another and, when they separate, return to their original forms. Thus solitons are conserved and behave like particles.