Twisted Lines Research Articles

MAGNETOHYDRODYNAMIC SIMULATION OF THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15. II. DYNAMICS CONNECTING THE SOLAR FLARE AND THE CORONAL MASS EJECTION

We clarify a relationship of the dynamics of a solar flare and a growing Coronal Mass Ejection (CME) by investigating the dynamics of magnetic fields during the X2.2-class flare taking place in the solar active region 11158 on 2011 February 15, based on simulation results obtained from Inoue et al. 2014. We found that the strongly twisted lines formed through the tether-cutting reconnection in the twisted lines of a nonlinear force-free field (NLFFF) can break the force balance within the magnetic field, resulting in their launch from the solar surface. We further discover that a large-scale flux tube is formed during the eruption as a result of the tether-cutting reconnection between the eruptive strongly twisted lines and these ambient weakly twisted lines. Then the newly formed large flux tube exceeds the critical height of the torus instability. The tether-cutting reconnection thus plays an important role in the triggering a CME. Furthermore, we found that the tangential fields at the solar surface illustrate different phases in the formation of the flux tube and its ascending phase over the threshold of the torus instability. We will discuss about these dynamics in detail.

Twisted lines: artificial muscle and advanced instruments can be formed from nylon threads and fabric.

At the mention of nylon, you may think of shirts, stockings, fishing line, and sutures. A recent discovery, first reported in February 2014 in Science, is that the strong, tough, and inexpensive threads that make up fabrics and filaments can actively contract and expand?with much greater force than muscle [1]. This newly discovered musclelike action creates opportunities in medical devices?among other areas?that are just beginning to be explored.

Mix-Mode S Parameters Analysis of Crosstalk for Twisted Differential Line on PCB

In this paper, twisted differential lines on multi-layer PCB is modeled with 3D Full-wave EM tool, and crosstalk is analyzed based on mix-mode S parameters. It is compared with traditional differential microstrip line. Then the simulation results demonstrate that twisted differential lines on multi-layer PCB can enhance immunity against crosstalk .

The Comparative Study between Twisted and Non-Twisted Distribution Line for Photovoltaic System Subjected to Induced Voltage Generated by Impulse Voltage

The Comparative Study between Twisted and Non-Twisted Distribution Line for Photovoltaic System Subjected to Induced Voltage Generated by Impulse Voltage

The Comparative Study Between Twisted And Non-Twisted Distribution Line For Photovoltaic System Subjected To Induced Voltage Generated By Impulse Voltage

The recent advancement of renewable energy sources and specifically photovoltaic system has resulted in outdoor installations of large power stations. A photovoltaic system is exposed to extreme ambient conditions due to the lightning strike activity that generated induced overvoltage which have a high tendency to affect the electrical apparatus especially renewable energy plant that directly exposed to this source. This study is performed through experimental work by comparing the effect of induced overvoltage propagation upon between the twisted and non-twisted distribution line for photovoltaic system. The induced voltage is performed by using lightning impulse generator. It is found that the maximum voltage of the unwanted signal is proportional with the distant of the specimen. The closer distant between solar panel material and spark discharge, the more serious effect would occur due to the induced overvoltage .

Electromagnetic Spider Web Application in Earthquake Prediction

Sharing seismometer; electromagnetic spider web; earthquake prediction; ASK wireless transmitter, receiver module; PLC ladder diagram)This paper introduces three practical seismometer design method, Convenient and practical sharing type seismometer can put an electromagnetic spider web is received by multiple users. Each receiver connected to the indicator through network, can be respectively in the central receiver are respectively received signal, using cheap watch movement timer or stopwatch timer, an hour on emission 3 seconds ASK signal, in terminal scanning receiving various, Interconnect can choose common network twisted pair network line directly by the receiving module by way of LED instructions or is composed of a single-chip microcomputer and software to determine the earth electromagnetic anomaly and alarm. Dedicated to the earthquake monitoring spatial electric field change, this is a very practical short impending earthquake prediction method. Here sharing seismic trial design is the result of years of hard work, mainly for residential or rural village, indicating that the method is like a thermometer indicates temperature, pressure gauge as intuitive atmospheric pressure.

MAGNETOHYDRODYNAMIC SIMULATION OF THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15. I. COMPARISON WITH THE OBSERVATIONS

We performed a magnetohydrodynamic (MHD) simulation using a nonlinear force-free field (NLFFF) in solar active region 11158 to clarify the dynamics of an X2.2-class solar flare. We found that the NLFFF never shows the drastic dynamics seen in observations, i.e., it is in stable state against the perturbations. On the other hand, the MHD simulation shows that when the strongly twisted lines are formed at close to the neutral line, which are produced via tether-cutting reconnection in the twisted lines of the NLFFF, consequently they erupt away from the solar surface via the complicated reconnection. This result supports the argument that the strongly twisted lines formed in NLFFF via tether-cutting reconnection are responsible for breaking the force balance condition of the magnetic fields in the lower solar corona. In addition to this the dynamical evolution of these field lines reveals that at the initial stage the spatial pattern of the footpoints caused by the reconnection of the twisted lines appropriately maps the distribution of the observed two-ribbon flares. Interestingly, after the flare the reconnected field lines convert into the structure like the post flare loops, which is analogous to EUV image taken by SDO. Eventually, we found that the twisted lines exceed a critical height at which the flux tube becomes unstable to the torus instability. These results illustrate the reliability of our simulation and also provide an important relationship between flare-CME dynamics.

The superconformal index of class $ \mathcal{S} $ theories of type D

We consider the superconformal index of class S theories of type D, which arise by compactification of the (2,0) D_n theories on a punctured Riemann surface C. We also allow for the presence of twist lines on C associated to the Z_2 outer automorphism of D_n. For a two-parameter slice (p=0, q, t) in the space of superconformal fugacities, we determine the 2d TQFT that computes the index.

Electromagnetic Coupling for Wire Twisting Pitch Optimization for SRS Applications

In the sensitive automotive applications like the safety restraint systems (SRS), twisted lines can be used to link the components of the system because of their property of reduction of the electromagnetic interference (EMI) coupling. Compared to the parallel lines, the twisted lines present the drawback to consume more copper in their manufacturing due to the greater length of their conductors. A parametric study based on the numerical modeling and the measurement of twisted lines is conducted in order to analyze the effect of the twisting pitch and of the untwisted part of these lines on the level of EMI coupling. This study will enable to optimize these two parameters in order to reduce the level of EMI coupling as well as the length of the conductors of the lines.

New N = 1 dualities from M5-branes and outer-automorphism twists

We generalize recent construction of four-dimensional $\mathcal{N}=1$ SCFT from wrapping six-dimensional $\mathcal{N}=(2,0)$ theory on a Riemann surface to the case of $D$-type with outer-automorphism twists. This construction allows us to build various dual theories for a class of $\mathcal{N}=1$ quiver theories of $SO-USp$ type. In particular, we find there are five dual frames to $SO(2N)/USp(2N-2)/G_2$ gauge theories with $(4N-4)/4N/8$ fundamental flavors, where three of them are non-Lagrangian. We check the dualities by computing the anomaly coefficients and the superconformal indices. In the process we verify that the index of $D_4$ theory on a certain three punctured sphere with $Z_2$ and $Z_3$ twist lines exhibits the expected symmetry enhancement from $G_2 \times USp(6)$ to $E_7$.

Design and Performance Study of a Dual-Element Multiband Printed Monopole Antenna Array for MIMO Terminals

This letter presents a study on linearly polarized compact multiband multiple-input-multiple-output (MIMO) antenna system for small mobile terminals. The MIMO antenna system consists of two symmetric printed monopole antennas with edge-to-edge separation of 0.097 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at 900 MHz. Each antenna element has a capacitive feed and is composed of two twisted lines, a parasitic loop, and a shorting trip that generate five resonant modes around 900, 1800, 2100, 3500, and 5400 MHz, covering GSM850/900, DCS, PCS, UMTS, WLAN, and WiMAX frequency bands. Two inverted-L shaped branches and a rectangular slot with one circular end, etched on the ground plane, were introduced to improve the isolation between antenna elements. The isolation achieved is higher than 15 dB in the lower band and 20 dB in the upper bands, leading to an envelope correlation coefficient of less than 0.025. The simulated performance of the designed antenna system has been verified in the experiment.

Innovative Magnetic Field Calculation from Multiple-Circuit Twisted Three-Phase Lines

Multiple-circuit twisted three-phase cable lines are typically used for connecting renewable resources (e.g. photovoltaic and wind power) to the power grid. The magnetic field generated by such lines should be evaluated carefully whenever connecting such renewables to the network. This paper examines for the first time the calculation of the magnetic field generated by such lines. In the framework of a worst-case approach, the paper extends to multiple-circuit twisted three-phase cables both the exact treatment derived from the literature about single-circuits and a simple innovative formula developed for single and double circuits by the authors, that resulted a good approximation of the rigorous analytical treatment and much more accurate than an approximated formula found in literature. The paper shows that the “worst case” approach yields an approximate yet conservative expression for the total magnetic field generated by multiple twisted three-phase power cables, whose effectiveness is further enhanced by the use of the simple innovative formula, as proved by case-studies examined here for triple-circuit twisted three-phase cables in various configurations.

Line defects in the 3d Ising model

We investigate the properties of the twist line defect in the critical 3d Ising model using Monte Carlo simulations. In this model the twist line defect is the boundary of a surface of frustrated links or, in a dual description, the Wilson line of the $ {{\mathbb{Z}}_2} $ gauge theory. We test the hypothesis that the twist line defect flows to a conformal line defect at criticality and evaluate numerically the low-lying spectrum of anomalous dimensions of the local operators which live on the defect as well as mixed correlation functions of local operators in the bulk and on the defect.

Wireless over cable for femtocell systems

Interference control is crucial to reach the expected spectral efficiencies in femtocell systems. Centralized and joint baseband (BB) processing of all femtocell signals can reduce inter-cell/intra-cell interference at the expense of fast signaling and strict synchronization to coordinate the multiple femtocell links. In this article, we revisit the conventional femtocell architecture by proposing the multi-cell baseband processing for interference mitigation based on a distributed antennas system. The proposed configuration resorts to the wireless over cable (WoC) paradigm and is based on the concept of replacing the in-house base station (Femtocell Access Point) with a home-device that simply transfers the analog radio frequency (RF) signals from the air-link to the existing cable connections. These home-devices act as bidirectional amplify-and-forward (AF) relays of air signals toward cable (and vice-versa) by operating a frequency conversion of the wireless spectrum to accommodate the cable specifications and coexistence with other services. Splitting RF processing (at home) from baseband processing (centralized at the nearest street cabinet or central office collecting multiple cables) guarantees that multi-cell processing exploits the same advantages as MIMO systems. The analysis of WoC for twisted pair telephone lines shows the advantages of the FemtoWoC architecture despite the coexistence with other interfering xDSL services over the cable, or the propagation over the widely deployed copper wirelines.

Twisted-Overlap Differential-Pair Approach to Increase Available Layout Space and Reliability in PCB Design

Modern electronic products require many high-speed differential pairs which require more layout space in PCB design. We propose a twisted-overlap differential-pair (TODP) structure to obtain more routing space and achieve better signal integrity in this study. TODP reduces the layout space requirement by about 25% compared with that required by traditional differential pairs and the twisted differential lines (TDL) structure [2]. Based on an eye diagram performance the TODP design compared to the traditional and TDL designs can improve the peak-to-peak jitter by 26.5% and 12.2%, the overshoot by 14.3% and 2%, the undershoot by 18.8% and 5%, and the eye width by 2 and 1%, respectively. Our results indicate that TODP may be of great benefit in differential-pair PCB design.

Influence of twist extrusion process on microstructure and mechanical properties of 6063 aluminum alloy

In this study, aluminum alloy 6063 was severely deformed by twist extrusion (TE) technique and its mechanical properties, before and after TE, was investigated using a die with the twist line slope of β=30°. It was revealed that large strains imposed on the material by this advanced method of severe plastic deformation (SPD) led to a nano-scale ultra-fine microstructure and to an enhancement of the mechanical properties. The more passes of TE the finer grained microstructure was produced. Also with increasing the number of TE passes, yield strength, ultimate tensile strength and hardness increased, while after relative reduction of uniform elongation and elongation to failure by intermediate passes they remained almost unchanged. Therefore, both the strength and ductility of the material were improved when deformed by twist extrusion.

Compact planar hexa-band inverted-F antenna for mobile phone application

This article presents a compact multiband planar inverted-F antenna design for mobile phone applications. The proposed antenna comprises dual twisted lines, a shorting strip and an L-shaped coupling strip. The dual twisted lines are excited by the coupling strip to generate four resonance modes around 900, 1800, 2100, and 3500 MHz and covers six bands including the global system for mobile communication 850/900 (824–894 MHz), (880–960 MHz), digital communication system (1710–1880 MHz), personal communication system (1850–1990 MHz) universal mobile telecommunication system (1920–2170 MHz) and worldwide interoperability for microwave access (3400–3600 MHz). The antenna shows a planar structure and occupies a very small-size of 15 × 26 mm2, making it especially suit for mobile phone applications. This research performed simulation by high frequency structure simulation and CST to design and analyze the antenna, and a practical structure was fabricated and tested. The measured and simulated return loss show good agreement. Moreover, the radiation patterns and the specific absorption rate are discussed too. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1233–1236, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25996

Colloids in Cholesterics: Size-Dependent Defects and Non-Stokesian Microrheology

We simulate a colloidal particle (radius R) in a cholesteric liquid crystal (pitch p) with tangential order parameter alignment at the particle surface. The local defect structure evolves from a dipolar pair of surface defects (boojums) at small R/p to a pair of twisted disclination lines wrapping around the particle at larger values. On dragging the colloid with small velocity v through the medium along the cholesteric helix axis (an active microrheology measurement), we find a hydrodynamic drag force that scales linearly with v but superlinearly with R-in striking violation of Stokes' law, as generally used to interpret such measurements.

Miniature Printed Octaband Monopole Antenna for Mobile Phones

In this letter, a compact printed monopole antenna with a capacitive feed capable of GSM850/900/DCS/PCS/UMTS/ WiMAX/HIPERLAN2/IEEE 802.11a operation in the mobile phone is presented. The proposed antenna is composed of dual twisted lines, a shorting strip, and a parasitic loop that generate five resonant modes around 900,1800, 2100 3500, and 5400 MHz. The antenna shows a planar structure and occupies a very small size of 15 ×26 mm2 or 3.9 cm2, making it especially suitable for mobile phone application. The antenna is simulated and designed by HFSS and CST to design and analyze the antenna. The measured and simulated results are in excellent agreement. Details of the antenna design are described, and its radiation performances including specific absorption rate (SAR) results are studied as well.

Twisted lines and small-scale structures in generation spectra of Yb-doped media excited by focused radiation of LiF:F 2 + color center laser

Spectral lines of Yb lasing in 1.03–1.05 μm region structured by 50–200 μm spots were found at focusing a pulsed LiF:F 2 + color center laser of 0.5–5.0 GW/cm2 intensity on highly doped Yb:YAG or Yb:glass plates in a resonator. Small spots at the spectrograph located ≈ 1 m apart from the resonator indicated a “sub-diffraction” directivity of Yb generation, 1–2 orders better than the diffraction limit 10−3–10−2 rad determined by the pumped volume dimensions. Observed features of Yb emission are explained assuming off-axis oscillations in Yb laser on phase-synchronized photons due to a strong spatial-angular selection of radiation in the resonator. Propagation of near diffraction free beams at angles to the axis built at the spectrograph slit for every 10–15 ns pulse of Yb generation a magnified “image” of a structure of generating channels in the active medium. This image projection brought a corresponding structure of spots in Yb spectra. It was found that channels may be formed due to a high-frequency spatial modulation (micrometers scale) of the refractive index profile in samples caused by the oscillating amplitude of thermoelastic stresses in the pumped medium. Obtained data demonstrate a possibility to study (with high spatial and temporal resolution) non-equilibrium stales of materials in small volumes using laser radiation emerging from these objects. This study results evidence for the novel concept of the spatial distribution of electromagnetic field of a photon: not in the form of a “travelling” wave but in the form of a wave with maxima and nodes located at fixed positions along the photon propagation direction.