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Context. Red supergiants are cool massive stars and are the largest and the most luminous stars in the Universe. They are characterized by irregular or semi-regular photometric variations, the physics of which is not clearly understood. Aims. The paper aims to derive the velocity field in the red supergiant star μ Cep and to relate it to the photometric variability with the help of the tomographic method. Methods. The tomographic method allows one to recover the line-of-sight velocity distribution over the stellar disk and within different optical-depth slices. This method was applied to a series of high-resolution spectra of μ Cep, and these results are compared to those obtained from 3D radiative-hydrodynamics CO5BOLD simulations of red supergiants. Fluctuations in the velocity field are compared with photometric and spectroscopic variations, the latter were derived from the TiO band strength and serve, at least partly, as a proxy of the variations in effective temperature. Results. The tomographic method reveals a phase shift between the velocity and spectroscopic and photometric variations. This phase shift results in a hysteresis loop in the temperature – velocity plane with a timescale of a few hundred days, which is similar to the photometric one. The similarity between the hysteresis loop timescale measured in μ Cep and the timescale of acoustic waves disturbing the convective pattern suggests that such waves play an important role in triggering the hysteresis loops., info:eu-repo/semantics/inPress

Correspondence from Michigan State Police to the Transient Bureau of Kalamazoo County, under the Federal Emergency Relief Administration, May 1933 - June 1943.

Correspondence from Michigan State Police to the Transient Bureau of Kalamazoo County, under the Federal Emergency Relief Administration, May 1933 - June 1943.

Correspondence from Michigan State Police to the Transient Bureau of Kalamazoo County, under the Federal Emergency Relief Administration, May 1933 - June 1943.

Correspondence from Michigan State Police to the Transient Bureau of Kalamazoo County, under the Federal Emergency Relief Administration, May 1933 - June 1943.

For further gravitational wave (GW) detections, it is significant to invent a technique to reduce all kinds of mirror displacement noise dominant at low frequencies for ground-based detectors. The neutron displacement-noise-free interferometer (DFI) is one of the tools to reduce all the mirror displacement noise at lower frequencies. In this paper, we describe a further simplified configuration of a neutron DFI in terms of neutron incidence direction. In the new configuration, neutrons enter the interferometer with unidirectional incidence at four speeds as opposed to two bidirectional incidences of opposite directions at two speeds as reported previously. This simplification of the neutron DFI is significant for proof-of-principle experiments.

For further gravitational wave (GW) detections, it is significant to invent a technique to reduce all kinds of mirror displacement noise dominant at low frequencies for ground-based detectors. The neutron displacement-noise-free interferometer (DFI) is one of the tools to reduce all the mirror displacement noise at lower frequencies. In this paper, we describe a further simplified configuration of a neutron DFI in terms of neutron incidence direction. In the new configuration, neutrons enter the interferometer with unidirectional incidence at four speeds as opposed to two bidirectional incidences of opposite directions at two speeds as reported previously. This simplification of the neutron DFI is significant for proof-of-principle experiments.

This paper focuses on image sensor communication (ISC) using cameras to receive wireless signals transmitted by visible lights. We summarize the technical principles of ISC from the perspective of transmitting devices. An introduction to the development and applications of ISC was provided, starting with the history of image sensors and visible light communication (VLC). Moreover, the communication mechanism of ISC using complementary metal–oxide–semiconductor (CMOS) sensors is explained in this paper. Specifically, we investigate studies using an optical communication image sensor and the rolling shutter technique for high-speed ISC. Further, we highlight three distinctive transmitting devices in ISC: a LED array, rotating LEDs, and displays, and explain them in terms of structure and signal transmission methods. In particular, we present the parallel transmission of LED arrays and their application in traffic systems and introduce an optical flow-based signal transmission method using rotating LEDs. In addition, two visual transmission techniques in displays-based-ISC using brightness-difference and high-frequency flashing are introduced, respectively. This paper intuitively explains these ISC techniques and reveals ISC’s high versatility.

In the general turning process, solutions for attaining the tool-workpiece relative position such as in-situ touch probes, external devices mounted with air/electric micrometers, and cameras are either indirect or cost/space-consuming. In this paper, a novel direct contact detection method based on the internal data of the machine tool servo and the self-identification strategy of the rotational center as an application of the detection method are proposed. The former method compares the internal data of the non-contact and contact motions, and then precisely identifies the contact position by processing it backwardly. The latter method makes multiple contacts on the pre-machined surface of the workpiece with a redundant-axis movement, and the rotational center identification is realized using the coordinates of contacts achieved by the former method. The effectiveness of the proposed methods is verified experimentally.

In the general turning process, solutions for attaining the tool-workpiece relative position such as in-situ touch probes, external devices mounted with air/electric micrometers, and cameras are either indirect or cost/space-consuming. In this paper, a novel direct contact detection method based on the internal data of the machine tool servo and the self-identification strategy of the rotational center as an application of the detection method are proposed. The former method compares the internal data of the non-contact and contact motions, and then precisely identifies the contact position by processing it backwardly. The latter method makes multiple contacts on the pre-machined surface of the workpiece with a redundant-axis movement, and the rotational center identification is realized using the coordinates of contacts achieved by the former method. The effectiveness of the proposed methods is verified experimentally.

Description of the elongational rheology of concentrated polymers appears to require that in fast flows the friction coefficient decreases with respect to its equilibrium value. However, the proposed models typically maintain the validity of the fluctuation-dissipation theorem (FDT) out of equilibrium. On the other hand, FDT is routed in local equilibrium, the latter being clearly violated by the flow-induced monomer coalignment that induces friction change. A recent analysis by Watanabe et al. [Macromolecules, 54, 3700 (2021)] of unentangled polystyrene (PS) melts, based on a nonlinear extension of the Rouse model, indicates that FDT is indeed violated in fast flows. According to their analysis, the Brownian force intensity remains almost independent of the flow rate, even though the friction coefficient drastically decreases. A different violation of FDT is shown by previous nonequilibrium molecular dynamics simulations of PS oligomers [Ianniruberto et al., Macromolecules, 45, 8058 (2012)] where the diffusion coefficient grows more than the inverse friction coefficient. In this paper, Brownian simulations using a multi-chain sliplink model (the so-called primitive chain network model) are reported for two monodisperse entangled PS melts, for which nonlinear shear and elongational data were published. Two different friction reduction models are examined, and the effect of switching FDT on and off is tested. Results demonstrate that, irrespective of FDT, both friction models can reasonably well reproduce the behavior shown by the data. This result lends support to models that retain FDT since its violation appears not to significantly affect predictions of nonlinear rheology.

Public investment is a central issue in the dynamic analyses of fiscal policy and economic growth. Debt financing for public investment and its effects have recently received great attention because interest rates have been low, almost invariably remaining below economic growth rates. This paper presents examination of the effects of debt-financed public investment subject to a simple fiscal rule in an overlapping generations model with public capital. This topic includes capital budgeting and the debt–deficit criterion of the Maastricht treaty. We show herein that debt financing for public investment enhances economic growth if an economy is dynamically inefficient and if public capital has a sufficiently large productivity effect. Moreover, it reduces economic growth rates in a dynamically efficient economy. Debt and growth can have a monotonic or non-monotonic relation, depending on the steady-state interest rate, growth rate, and productivity effect of public investment. The findings indicate that debt–growth relations match with controversial empirical evidence. Furthermore, existing generations choose perfect debt finance if dynamic inefficiency exists. In contrast, a balanced budget is preferred in a dynamically efficient economy with low productivity effects of public capital. However, an economy with high productivity effects of public capital might cho ose debt financing. This paper contributes to the elucidation of currently emphasized issues of public investment.

The linear relationship between wave amplitude and wave torque based on the boundary element method (BEM) is widely employed for small-amplitude waves. However, linear relationships are unsuitable for bottom-hinged oscillating wave surge converters (OWSCs) under high waves owing to nonlinearities, such as wave overtopping. This paper presents an improved BEM introducing an incident wave amplitude correcting factor to simplify the complex nonlinearities under high regular waves. The correcting factors were calibrated with computational fluid dynamics (CFD) using OpenFOAM. An Oyster 800-like OWSC was adopted as the study model. A quadratic fitting curve of correcting factor vs. wave height is applicable because the calibrated correcting factors significantly correlate with wave heights but are almost irrelevant to wave periods. Though the time–history responses differ in BEM and CFD under high waves, BEM-based time-averaged results show good accuracy and high computational efficiency, such as equivalent pitch amplitude and capture width ratio (CWR). At mid-low periods, simultaneously varying power take-off (PTO) stiffness and damping than solely varying PTO damping, significantly increases CWR, especially under low waves. The capturing power under high waves substantially increases because of pitch motion amplification. At long periods, adjusting PTO inertia produces negligible efficiency improvement even with amplified oscillation.

This paper analyzes tax competition and coordination, determining which is better in a multi-region endogenous growth model. With an integrated capital market, increased capital tax in one region generates external benefits to others through an increased tax base originating from capital flight. Because this efficiency cost affects resource allocation between private and public goods and intertemporal consumption and investment choice, a higher cost derives a lower equilibrium capital tax rate, leading to a higher economic growth rate. Consequently, the inefficiency costs exert two opposite welfare effects via inefficiently low public goods supply and high economic growth. Naturally, tax coordination to cope with severe tax competition is welfare improving to resolve the underprovision of public goods instead of accepting low growth. In contrast, tax coordination is not desirable if tax competition is mild because benefits from high growth outweigh the costs of an undersupply of public goods.

This paper analyzes tax competition and coordination, determining which is better in a multi-region endogenous growth model. With an integrated capital market, increased capital tax in one region generates external benefits to others through an increased tax base originating from capital flight. Because this efficiency cost affects resource allocation between private and public goods and intertemporal consumption and investment choice, a higher cost derives a lower equilibrium capital tax rate, leading to a higher economic growth rate. Consequently, the inefficiency costs exert two opposite welfare effects via inefficiently low public goods supply and high economic growth. Naturally, tax coordination to cope with severe tax competition is welfare improving to resolve the underprovision of public goods instead of accepting low growth. In contrast, tax coordination is not desirable if tax competition is mild because benefits from high growth outweigh the costs of an undersupply of public goods.

Principal Investigator: Shengshan Wu