Abstract From our Secret Lives of Cepheids program, the prototype Classical Cepheid, δ Cep, is found to be an X-ray source with periodic pulsation-modulated variations. This finding complements earlier reported phase-dependent FUV–UV emissions star that increase ∼10–20 times highest fluxes at <?CDATA $\sim 0.90\mbox{--}0.95\phi $?> , just prior maximum brightness. Previously Cep was as potentially variable, using XMM-Newton observations. Additional phase-constrained data were secured Chandra...

The proposed work conducts a new approach for modeling dual band monopole antenna design using DGS assisted by ANN. In the aim of efficient with gain and optimal impedance matching, Artificial Neural Networks technique (ANN) is used development process. This presents H-slotted Defected Ground Structure (DGS) based ANN 5G Sub-6 GHz applications. designed operates at 3.76 6.1 GHz. 2.18 dB 2.75 both frequencies, respectively. Firstly, simulation performed CST EM simulator, then predicted...

A new broadband phased array antenna with wide-scan and high-gain beam-scanning are desirable to meet the requirements of future cellular networks. This paper discusses characteristics a beam-steerable design having broad bandwidth for 5G communications. The discussion is focused on smartphones, due their small size complexity. procedure straightforward accomplished mainboard smart handheld devices. introduced involves eight metamaterial-based dipole resonators 1×8 linear form. have sizes...

We describe a method to construct theoretical, time-dependent, two-component and wave heated chromosphere models for late-type dwarfs. The depend only on four basic stellar parameters: effective temperature, gravity, metallicity filling factor, which determines the coverage of these stars by surface magnetic fields. They consist non-magnetic regions acoustic waves vertically oriented flux tubes longitudinal tube with contributions from transverse waves. Acoustic, energy spectra fluxes...

ABSTRACT This study presents new prediction models of the 11-yr solar activity cycles (SC) 25 and 26 based on multiple indicator parameters. The developed are use non-linear autoregressive exogenous (NARX) neural network approach. training period NARX model is from July 1749 to December 2019. considered parameters monthly sunspot number time series (SSN), flare occurence frequency, 10.7-cm radio flux, total irradiance (TSI). fed by these independently results compared verified. obtained...

In the first paper of this series we developed a method to construct theoretical, time-dependent and two-component chromosphere models for late-type main sequence stars. The consist non-magnetic regions heated by acoustic waves magnetic flux tube waves. By specifying filling factor, theoretical stellar atmospheres with different chromospheric activity can be calculated. Here, these are used simulate emerging Ca II Mg emission fluxes compare them observations. comparison shows that wave...

In this manuscripts, H-slotted DGS based antenna configuration for K/Ku applications is designed, fabricated and measured using ROHDE & SCHWARZ ZVB20 network analyzer. Simulation studies are performed Electromagnetic Software CST Studio Suite. Moreover, a development of Artificial Neural Networks (ANN) model implemented on feedforward back-propagation Bayesian regularization learning algorithm. The optimal position performance predicted in terms reflection coefficient resonance frequency....

Abstract This paper presents a graphene-based antenna array for terahertz (THz) applications. The suggested has four radiating square shaped patches fed by coplanar waveguide (CPW) technique. proposed operates at the three frequencies with operational bandwidths of 1.173–1.210 THz (at 1.19 THz), 1.270–1.320 1.3 GHz), and 1.368–1.346 1.4 GHz). total area is reported as 1000 × µm 2 , printed on Silicon substrate thickness 20 dielectric constant ϵ r = 11.9. To enhance structure’s performance...

The wave energy fluxes carried by longitudinal tube waves along thin vertical magnetic flux tubes embedded in atmospheres of late-type stars are computed. main physical process responsible for the generation these is nonlinear time-dependent response to continuous and impulsive external turbulent pressure fluctuations, which represented here an extended Kolmogorov spatial modified Gaussian temporal spectrum. Both spectra calculated population I with effective temperatures ranging from Teff =...

A dual band Substrate Integrated Waveguide; SIW microstrip patch antenna based on periodic H-Defected Ground Structure; H-DGS is designed for Ku applications. techniques provide low cost, small size and convenient integration with planer circuit. The proposed structure a Roger 5058 substrate thickness of 1.6 mm, 2.2 dielectric constant tangent loss 0.0009. performance analysis the antennas performed using finite element methods, simulation results show gain directivity 7.03 dB 7.38...

Theoretical chromospheric models described in the two previous papers of this series are used to study relationship between emission and filling factor. This theoretically determined shows that flux Ca II (H+K) is approximately proportional square root magnetic factor at stellar surface. To relate rotation rate, we compare theoretical fluxes with observations stars known period. The comparison Rossby number probably a more appropriate measure influence on activity main-sequence than Our Mg...

The main aim of this paper is to perform first self-consistent numerical computation the response stellar atmospheres propagation acoustic waves specified by realistic wave energy spectra. In approach, are stratified, non-isothermal and plane-parallel, only their magnetic-free regions considered. resulting atmospheric heating calculated time sequence velocities computed a time-dependent hydrodynamic code analysed. All computations done adiabatically Fourier analysis used in order determine...

In the present work we expand study of time-dependent ionization previously identified to be pivotal importance for acoustic waves in solar magnetic flux tube simulations. We focus on longitudinal (LTW) known an important heating agent regions. Our models also consider new results wave energy generation as well updated determination mixing length convection now 1.8 scale heights upper convective layers. 1D simulations chromosphere by studying tubes different spreading a function height aimed...

In the current work, a new Wideband Substrate Integrated Waveguide Bandpass Filter (SIW-BPF) is presented. The target to allow vertical roaming between X and Ku band applications. As first step, we performed parametric study of different etched slot geometries namely, H-Slotted, T-Slotted, U-Slotted DGS in order examine effects altering geometrical parameters unit on its response. H-Slotted shows highest FBW with 82.89% average compared other geometries. second cell size numbers were...

Theoretical time-dependent and two-component chromospheric models for late-type dwarfs are constructed based on acoustic magnetic wave heating mechanisms. The used to predict the theoretical range of activity these stars. Comparison this with one established observationally shows that alone can explain most but not all observed stellar activity.

On the way to design Substrate Integrated Waveguide Bandpass Filter (SIW-BPF) for wideband applications a parametric study of slot geometry etched on SIW structure is preliminary step such filter. Three different structures, namely, H-Slotted, T- Slotted, and U-Slotted investigated in order examine effect altering geometrical parameter unit its response. H-Slotted Electromagnetic Band Gap (EBG) shows highest Fractional Width (FBW), which about 90% compared others, consequently it could be...

Context. Continued investigation of the linkage between magneto-acoustic energy generation in stellar convective zones and dissipation radiative emission outer atmospheres stars different activity levels. Aims. We compute wave fluxes carried by longitudinal tube waves along vertically oriented thin magnetic tubes embedded theoretical main-sequence based on parameters deduced R. L. Kurucz D. F. Gray. Additionally, we present a fitting formula for flux governing parameters. Methods. A modified...

The fifth generation (5G) is the next wireless mobile communication technology that targets to provide huge capac-ity, low latency and high data speeds. Like any new technology, 5G requires development of exciting techniques, where access frequency spectrum can achieve desired characteristics. In addition, systems must be developed designed using wide bandwidth microwave components, which should implemented with modern efficient guiding structures. Among all directional coupler essential...

A novel circular reconfigurable metasurface (MS) based compact ultra-wideband (UWB) hybrid coupler is developed for Ku-band applications. The using the substrate-integrated gap waveguide (SIGW) technology. structure consists of two layers, bottom layer represents artificial magnetic surface periodic structures and ridges in between that guide wave required direction with minimum dispersion. It involves coupling section a centered etched slot additional vias to achieve basic properties. This...

This study presents a new circular compact Ultra Wide-Band (UWB) substrate integrated gap waveguide (SIGW) based 3 dB hybrid coupler for Ku band applications. The coupling section is structure with an elliptic slot and additional via to achieve equal-power division in two ports isolation the 4 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> port. To optimize design parameters of coupler, Finite Integration Time-Domain (FITD) approach...

This paper is devoted to the design and implementation of smart watch textile antenna for Wi-Fi bio-medical applications in millimetric wave bands. The implemented on leather textile-based substrate be embedded a watch. It enables pick up signals without need connected mobile through Bluetooth. operates at 60 GHz or WiGig (Wireless Gigabit Alliance) band with wide higher-rate applications. also could over many stratified layers body organisms used diagnosis diseases like diabetes cancer....

The current work is an attempt to predict building reactions big earthquakes using real data collected from surveys carried out after the occurrence of earthquakes. With development damage functions for in Turkey one can levels as a function earthquakes' intensity and parameters. Our model based on neural networks techniques which allow non-linear correlations be taken into account. We analyse damaged buildings following three earthquakes: Afyon (2002; Mw = 6.0), Bingöl (2003; 6.4) Düzce...