Is OJ 287 a Single Supermassive Black Hole?

Light curves for more than century optical photometric observations of the blazar OJ 287 reveals strong flares with a quasi-period of about 12 years. For a long time, this period has been interpreted by processes in a binary black hole system. We propose an alternative explanation for this period, which is based on Doppler factor periodic variations of the emitting region caused by jet helicity. Using multi-epoch very large baseline interferometry (VLBI) observations carried out in a framework of the MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) program and other VLBA (Very Long Baseline Array) archival experiments at the observing frequency of 15 GHz, we derived geometrical parameters of the jet helix. To reach an agreement between the VLBI and photometric optical observation data, the jet component motion at a small angle to the radial direction is necessary. Such non-radial motion is observed and, together with the jet helical shape, can be naturally explained by the development of the Kelvin–Helmholtz instability in the parsec-scale outflow. In this case, the true precession of the OJ 287 jet may manifest itself in differences between the peak flux values of the 12-year optical flares. A possibility to create this precession due to Lense–Thirring effect of a single supermassive black hole is also discussed.

MODULATION INSTABILITY IN TWO COMPONENT BOSE-EINSTEIN CONDENSATE WITH RELATIVE COMPONENT MOTION

The development of modulation instability in a spatially homogeneous two-component Bose-Einstein condensate (BEC), in which the interacting components move through each other at a relative speed, is investigated. It is shown that nonlinear dynamics, leading to modulation instability, is determined by both the values of the constant interaction and the relative velocity between the components. The maximum oscillation increment is found and the limits of the existence of modulation instability in the space of wave numbers are determined.

Theoretical Prediction and Experimental Validation of Dynamic Deformation During Machining of Thin-Walled Structure

Dynamic deformation of thin-walled structure during side milling is investigated in present paper. The component is modeled as a cantilever plate while the milling force is modeled as a moving excitation for the component. Classical plate theory is employed to construct the component motion equations. Modal superposition method is employed to solve the equation to obtain the dynamic deformation. At last, experiments and simulation are implemented, results of digital simulation and experiments are compared and they matched well with each other, which demonstrates the validation of the method for computing dynamic deformation in this paper. Moreover, analyzed results in this paper are also compared with FEM results which were obtained by other investigators and shows better accuracy.

The effect on dynamics of using various transmission designs for two-stage cycloidal speed reducers

This paper investigates different transmission methods for a two-stage speed reducer by analyzing component motion and stress conditions during reducer operation. First, an exemplar (set) speed-reducing ratio is used to develop four differently structured two-stage speed reducers: a traditional design using two serially connected single-stage speed reducers, an Rotate Vector (RV) reducer constructed by serially connecting a cycloid speed reducer and an involute planet gear reducer, and two new concept designs. The first new concept named “New design 1” has a pin component in which a cam pair and pins connect two-stage cycloidal gears having different tooth numbers. The second new concept named “New design 2” has a center disc component in which a cam pair symmetrically connects two-stage cycloid gears with different tooth numbers. These four structural types of two-stage speed reducer form the basis for a system dynamics analysis model used to analyze the main components’ motion and stress variation conditions. Besides, this study also carries out the cycloid internal gear (nonpinwheel design) to replace the pinwheel in these four-structured two-stage speed reducers. The results highlight the differences and shortcomings of the four transmissions with pinwheel and nonpinwheel designs, including the dynamic load imbalance and stress peaks phenomena caused by design inadequacies.

Temporal and spatial limits of pattern motion sensitivity in macaque MT neurons

Many neurons in visual cortical area MT signal the direction of motion of complex visual patterns, such as plaids composed of two superimposed drifting gratings. To compute the direction of pattern motion, MT neurons combine component motion signals over time and space. To determine the spatial and temporal limits of signal integration, we measured the responses of single MT neurons to a novel set of “pseudoplaid” stimuli in which the component gratings were alternated in time or space. As the temporal or spatial separation of the component gratings increased, neuronal selectivity for the direction of pattern motion decreased. Using descriptive models of signal integration, we inferred the temporal and spatial structure of the mechanisms that compute pattern direction selectivity. The median time constant for integration was roughly 10 ms, a timescale characteristic of integration by single cortical pyramidal neurons. The median spatial integration field was roughly one-third of the MT receptive field diameter, suggesting that the spatial limits are set by stages of processing in earlier areas of visual cortex where receptive fields are smaller than in MT. Interestingly, pattern direction-selective neurons had shorter temporal integration times than component direction-selective neurons but similar spatial integration windows. We conclude that pattern motion can only be signaled by MT neurons when the component motion signals co-occur within relatively narrow spatial and temporal limits. We interpret these results in the framework of recent hierarchical models of MT.

Storyboard dalam Pembuatan Motion Graphic

Motion graphics is one category in the animation that makes animation with lots of design elements in each component. Motion graphics needs long process including preproduction, production, and postproduction. Preproduction has an important role so that the next stage may provide guidance or instructions for the production process or the animation process. Preproduction includes research, making the story, script, screenplay, character, environment design and storyboards. The storyboard will be determined through camera angles, blocking, sets, and many supporting roles involved in a scene. Storyboard is also useful as a production reference in recording or taping each scene in sequence or as an efficient priority. The example used is an ad creation using motion graphic animation storyboard which has an important role as a blueprint for every scene and giving instructions to make the transition movement, layout, blocking, and defining camera movement that everything should be done periodically in animation production. Planning before making the animation or motion graphic will make the job more organized, presentable, and more efficient in the process.