Appearance Of Rotation Research Articles

THRESHOLD EFFECT IN DUSTY CLUSTERS IN A MAGNETIC FIELD

The process of occurrence of rotational motion of dusty plasma in a longitudinal magnetic field was investigated. It was experimentally found that the occurrence of rotation depends on the number of dust particles in the direction perpendicular to the magnetic induction vector, as well as on their vertical position in the dust trap (i.e., the magnitude of the electric field). The value of the threshold for the appearance of rotation in the magnetic field at a constant number of particles depends on the particle size and discharge conditions. The parameters of the experiment are selected, at which the effect manifests itself in detail. It has been established that for stationary rotation, a stable position of dust particles in the cross section is required, which corresponds to the filling of the shells of a rotating dust structure.

Fragmentation, rotation, and outflows in the high-mass star-forming region IRAS 23033+5951

Context. The formation process of high-mass stars (>8 M⊙) is poorly constrained, particularly the effects of clump fragmentation creating multiple systems and the mechanism of mass accretion onto the cores. Aims. We study the fragmentation of dense gas clumps, and trace the circumstellar rotation and outflows by analyzing observations of the high-mass (~500 M⊙) star-forming region IRAS 23033+5951. Methods. Using the Northern Extended Millimeter Array (NOEMA) in three configurations and the IRAM 30 m single-dish telescope at 220 GHz, we probe the gas and dust emission at an angular resolution of ~0.45′′, corresponding to 1900 au. Results. In the millimeter (mm) continuum emission, we identify a protostellar cluster with at least four mm-sources, where three of them show a significantly higher peak intensity well above a signal-to-noise ratio of 100. Hierarchical fragmentation from large to small spatial scales is discussed. Two fragments are embedded in rotating structures and drive molecular outflows, traced by 13CO (2–1) emission. The velocity profiles across two of the cores are similar to Keplerian but are missing the highest-velocity components close to the center of rotation, which is a common phenomena from observations like these, and other rotation scenarios are not excluded entirely. Position–velocity diagrams suggest protostellar masses of ~6 and 19 M⊙. Rotational temperatures from fitting CH3CN (12K− 11K) spectra are used for estimating the gas temperature and thereby also the disk stability against gravitational fragmentation, utilizing Toomre’s Q parameter. Assuming that the candidate disk is in Keplerian rotation about the central stellar object and considering different disk inclination angles, we identify only one candidate disk as being unstable against gravitational instability caused by axisymmetric perturbations. Conclusions. The dominant sources cover different evolutionary stages within the same maternal gas clump. The appearance of rotation and outflows of the cores are similar to those found in low-mass star-forming regions.

On the locality of the kinetic energy transfer in a wave space

For the model of thermal turbulence in the Boussinesq approximation with heating from below a change in the structure of the nonlinear interaction of the harmonics of the velocity field with the appearance of rotation is examined. The parameters of convection with rotation are chosen in such a way to correspond to the typical regimes in the models of the planetary dynamo. For such regimes, the structure of the triadic mechanism of the kinetic energy transfer through the spectrum is investigated.

Pseudorotation of the little finger metacarpal

Fractures of the little finger metacarpal are common, and are often associated with significant soft-tissue swelling and the appearance of rotational malalignment when the fingers are flexed. Our hypothesis is that soft-tissue swelling causes this apparent rotational deformity of the flexed little finger. The fourth intermetacarpal spaces of three of the authors’ non-dominant hands were injected with saline. Following injection, all the hands exhibited the appearance of internal rotation of the little finger. The mean change in rotation was 16° and the maximum was 25°. There was no change in the plane of the nail plate in extension in any hand. We conclude that soft-tissue swelling can cause the appearance of internal rotation of the flexed little finger in the absence of fracture.

Prediction of iron loss in rotating machines with rotational loss included

Iron loss prediction is an important issue in both design and analysis of electrical machines. Because of their complicated structure, flux distribution, and rotational variation of flux, it is difficult to predict the iron loss in a machine exactly. This paper studies the iron loss in the core of rotating machines in which the rotational field is dominant, using the finite-element method. For electrical machines in practical operation, additional iron losses due to the appearance of rotation of flux vectors and harmonic flux densities make the calculation results deviate from the measured data. We have revised the method to account for these excess iron losses by considering both the influences of flux vector rotations and flux density harmonics. Calculation and experiments on two kinds of interior permanent-magnet synchronous motors have verified that our method produces results that agree well with the experimental ones.

Evaluation of Iron Loss in Interior Permanent Magnet Synchronous Motor with Consideration of Rotational Field

Loss evaluation is an important issue in the design of electrical machines. Due to the complicate structure and flux distribution, it is difficult to predict the iron loss in the machines exactly. This paper studies the iron loss in interior permanent magnet synchronous motors based on the finite element method. The iron loss test data of core material are used in the fitting of the hysteresis and eddy current loss constants. For motors in practical operation, additional iron losses due to the appearance of rotation of flux density vector and harmonic flux density distribution makes the calculation data deviates from the measured ones. Revision is made to account for these excess iron losses which exist in the practical operating condition. Calculation results show good consistence with the experimental ones. The proposed method provides a possible way to predict the iron loss of the electrical machine with good precision, and may be helpful in the selection of the core material which is best suitable for a certain machine.

Rotation of the central pair microtubules in eukaryotic flagella.

SUMMARY It has been 20 years since the phenomenon of centralpair rotation in eukaryotic flagella was reported(Omoto, and Kung, 1979). At that time, a model wasproposed in which the central pair functions as adistributor to regulate dynein activity among the outerdoublet microtubules. The video evidence obtainedsince then and gathered together in this essay is con-sistent with this model. Geometric arguments indicatethat there must be circumferential and longitudinalregulation of shear forces to produce effective bendingmotion of an axoneme. Central pair microtubules areideally situated to perform this regulatory function.The regulation of outer doublet sliding by the centralpair, together with the rotation of the latter, where thisoccurs, may explain the wide diversity of two- andthree-dimensional flagellar and ciliary waveforms thatis found in organisms using the same basic 9 1 2structure. ACKNOWLEDGMENTS We thank Mike McLaughlin of Material Media Services, Washing-ton State University for converting 16-mm film to video format, andDenise A. Palmen (Technical Services, Washington State University)for editing the videos, assembling the QuickTime movies, and pro-ducing the jpeg images to use as figures. The research based onvideo images shown in this essay was first published by Kamiya(1982), Omoto and Witman (1981), Gibbons

Rotational components of deformation in metal bodies under dynamic loading

The plane problem of an initially quiescent cylinder subjected to a gradient flow of a highly viscous fluid is solved. It is shown that the cylinder is brought into rotation with angular velocity ω=−ee, where ee in the shear-strain rate of the medium. The solution is used to analyze flows under high-rate loading of metallic bodies that occurs at the level of the microstructure. The appearance of rotation is associated with the presence of fragments in the structure of the substance (grains, fragments, cells, and inclusions) that are unable to change their shape under the given loading conditions and, consequently, begin to rotate in the process of shear strain. Rotations that occur at the microlevel during joint deformation of solid bodies lead to transfer of oxide, hydroxide, and other surface films into the depth of the material, and this contributes to formation of a bond.

The rotated-lamina syndrome. III. Cases in Begonia, Corylus, Magnolia, Pellionia, Prunus, and Tilia

The rotated-lamina syndrome occurs in all adult shoots of Tilia × europaea, and in lateral shoots of Corylus spp. and Prunus laurocerasus. Corylus and Prunus also have orthotropic radially symmetrical shoots that have normal leaf orientation. Development of the syndrome in leaf primordia in Tilia and Corylus is similar to that previously described in Ulmus, i.e., the leaf primordium is initially asymmetrical so that the leaf blade component of the primordium arises facing only obliquely towards the shoot apex, and further asymmetrical outgrowth of the leaf buttress brings the leaf blade region into the rotated position. Leaves of Begonia foliosa and the ventral leaves of (anisophyllous) Pellionia pulchra arise from initially symmetrical primordia, and lamina rotation occurs by asymmetric growth at the base of the leaf blade region. The process is similar to that in the woody examples but occurs at a proportionately later stage of leaf development. Development of the syndrome in Prunis laurocerasus and Magnolia × soulangeana differs considerably. Primordia are slightly asymmetrical but have normal dorsiventrality at first, but when the lamina arises the two edges of the leaf blade grow towards the same (upper) side of the bud, and this is responsible for most of the appearance of rotation. In general the upper stipule is initially larger than the lower and arises much earlier in Corylus and Tilia. Leaves that have normal orientation in Corylus and Prunus develop from quite symmetrical primordia, but those of Cotylus may show some asymmetry of stipule development. Shoots of all cases can be considered to show heteroblastic growth, and the early part of the heteroblastic sequence is prolonged in the orthotropic shoots with normally oriented leaves in Corylus and Prunus. The morphological and morphogenetic significance of the rotated-lamina syndrome is discussed. Key words: Begonia, Corylus, Magnolia, Pellionia, Prunus, Tilia, leaf, development, dorsiventrality, lamina rotation.

Dopamine-like action of nicotine: lack of tolerance and reverse tolerance

Rats with unilateral 6-hydroxydopamine lesions of the substantia nigra became briefly sedated and hypothermic after the acute injection of nicotine s.c. (0.4 or 0.8 mg/kg free base). When nicotine was repeated 5 days per week there was rapid tolerance for the sedation and slower tolerance for the hypothermia and the lesioned animals began to rotate ipsiversively after each injection. Stereotypic behavior was also noted. Rats injected with nicotine 5 days per week and nigrally lesioned on the 24th day rotated promptly on their first postoperative injection of nicotine. The nicotinic antagonist, mecamylamine (1.0 mg/kg i.p.), completely blocked the induced rotation. The appearance of rotation did not seem to depend on tolerance to sedation. The direction of rotation indicated enhancement of activity in the intact nigrostriatal system. However, 10 min after the acute injection of 0.8 mg/kg nicotine no change was found in the ratios of dopamine to its metabolites DOPAC and homovanillic acid in the substantia nigra, caudate-putamen, nucleus accumbens, olfactory tubercle, frontal cortex, or ventral tegmental area. Rats given 0.4 or 0.8 mg/kg nicotine 5 days per week and either lesioned prior to nicotine or lesioned during the third week rotated during the sixth week without any sign of tolerance. One day after the 30th injection in intact or lesioned rats the ratios of dopamine to its metabolites did not differ from those in saline controls on either the right or left side of any of the regions examined. There was no evidence of a change in dopamine metabolism after an acute challenge with nicotine or of a sustained change after repeated injection. The possibility remains that repeated nicotine modifies the dopaminergic response to nicotine without causing a sustained change in metabolism.

Molecular Motion and 19F Relaxation in the Liquid Hexafluorides of Molybdenum, Tungsten, and Uranium

In order to study molecular motion in liquid molybdenum, tungsten, and uranium hexafluorides, we have undertaken a 19F relaxation study in these liquids. Measurements of the relaxation times as a function of resonance frequency show that the dominant relaxation mechanism is the modulation of the spin—rotation interaction by the molecular motions. It is shown that the strengths of the spin—rotation interactions, which have not been measured directly, can be deduced very simply from the chemical-shift tensors if some approximations are made. The molecular motion is discussed with the help of a generalized Langevin equation in which it is not required that the particle under consideration be much heavier than the molecules interacting with it. It is thus found that the hexafluoride molecules in the liquid phase can rotate through an angle of about 1 rad at 70°C before their angular velocity changes and that this intermediate degree of rotation is consistent both with the low values of the entropies of fusion, which indicate that the rotations do not occur freely, and with the appearance of rotation—vibration structures in their infrared absorption spectra. The self-diffusion coefficients were also measured as a function of temperature. The relationship between the diffusion coefficients and the longitudinal relaxation times is not in agreement with Hubbard's theory, and this is attributed to the failure of both the Stokes' equation and the rotational diffusion model.

An Optical Phenomenon

IN addition to the accounts in NATURE referred to by Mr. J. W. Giltay in your issue of November 22, the phenomenon mentioned by me in NATURE of October 18 had previously been far more fully described by Dr. John Aitken in a paper “On a New Variety of Ocular Spectrum” in the Journal of Anatomy and Physiology, vol. xiii., p. 322; and, as stated in this paper, the phenomenon noticed by Mr. C. Carus Wilson (NATURE, October 25), when travelling by train in a rear coupe compartment, was described by Prof. Silvanus Thompson in the report of the British Association for 1877. Dr. Aitken experimented with rotating discs divided into about twenty-four sectors, white and black alternately, and with endless bands of paper with black bars painted across them. A convenient way of viewing the apparent motion was to look at a sheet of mottled paper, after looking at the rotating disc or moving band, when the markings on the paper appeared to move in a contrary direction to the exciting impression. Though some of the mottlings seem to flow past the others, it was found by Dr. Aitken that a straight line drawn across “the spectral stream” did not appear to be bent, as one might have supposed would be the case. If, after viewing the rotating disc, another similar disc or the drawing of a wheel is looked at, the second disc or the wheel appears to rotate in a contrary direction to the first; but if the second disc is larger than the first, or the spokes of the wheel are extended to a greater size than the rotating disc, “this extension will entirely destroy all appearance of rotation, and the wheel will appear at rest. Do not these last experiments suggest that the seat of illusion is deeper than the retina?”