Loop Effects Research Articles

Data Encoding Improvement and Size Reduction of Chipless RFID Tag Using Short-circuit Line Effect and Angle-based Divided Loops

This paper focuses on a short circuit and concentric loop effects to improve the structure dimension as well as enhance the ability to encode electromagnetic wave data for chipless RFID tags. The tag is composed of star-shaped rings that are concentrically nested together. The following factors help reduce the tag size: using the phenomenon of electromagnetic backscattering, assessment by the Radar Cross Section (RCS), the antenna-free tag only includes the multi-frequency resonators. By inserting short circuit lines combined with concentric loops, the number of resonant peaks increases exponentially without increasing the tag overall dimension. In addition, by inserting the short circuit lines at different angles between the two consecutive loops, we can adjust the resonant frequency in the frequency bands, thereby changing the value of the bit by shifting the frequency position. The overall dimension of the resulted tag is 13mmx13 mm and the tag is aimed to be a printable tag on the flexible substrate to minimize the fabrication cost. With the 18-vertex star-shaped tag with five concentric loops, this chipless RFID tag can encode up to 16 bits with high resolution and large data density.

Loop spin effects in intense background fields

Radiative and non-radiative electron spin flip probabilities are analysed in both plane wave and focussed laser backgrounds. We provide a simple and physically transparent description of spin dynamics in plane waves, and demonstrate that there exists a kinematic regime in which the usual leading order perturbative hierarchy of QED is reversed, and non-radiative loop effects dominate over radiative tree-level spin-flips. We show that while this loop-dominance becomes suppressed in focussed laser pulses due to a high sensitivity to field geometry, there is nevertheless a regime in which, in principle, loop effects on spin transitions can be discerned.

The Growing Demand in Europe for Reconstructive Clitoral Surgery after Female Genital Cutting: A Looping Effect of the Dominant Discourse?

When activism to combat «female circumcision» gained momentum in the 1980s, a discursive gap was created that persists until today. On the one hand, campaigners, activists, governments and some scholars promoted a discourse that focused on these practices as mutilations; on the other hand, not all scholars were willing to adopt the new term (FGM, «female genital mutilation») or to drop the perspective that these practices must be described within their wider contexts, with the full variations in different settings. Starting from this gap, this article discusses «reconstructive clitoral surgery», or «clitoris repair», as a cultural phenomenon growing out of the first discursive stream. Using Ian Hacking’s concepts «interactive kinds» and «looping effect», I argue that the increasing demand for reconstructive clitoral surgery in European countries needs to be understood in relation to the dominant anti-FGM discourse. While many interdisciplinary teams around Europe strive toward providing a holistic and respectful care for women requesting the surgery, I contend that the ubiquitous anti-FGM discourse has negative effects for both circumcised women who opt for surgery and those who do not.

Health anxiety and attentional bias toward virus-related stimuli during the COVID-19 pandemic

After the COVID-19 worldwide spread, evidence suggested a vast diffusion of negative consequences on people's mental health. Together with depression and sleep difficulties, anxiety symptoms seem to be the most diffused clinical outcome. The current contribution aimed to examine attentional bias for virus-related stimuli in people varying in their degree of health anxiety (HA). Consistent with previous literature, it was hypothesized that higher HA would predict attentional bias, tested using a visual dot-probe task, to virus-related stimuli. Participants were 132 Italian individuals that participated in the study during the lockdown phase in Italy. Results indicated that the HA level predicts attentional bias toward virus-related objects. This relationship is double mediated by the belief of contagion and by the consequences of contagion as assessed through a recent questionnaire developed to measure the fear for COVID-19. These findings are discussed in the context of cognitive-behavioral conceptualizations of anxiety suggesting a risk for a loop effect. Future research directions are outlined.

Exchange bias behavior on permanent magnet Nd–Fe–B

In this study, Nd–Fe–B magnets with the type of N42 were employed to modify the microstructure and the magnetic properties. The Nd2Fe14B spherical grains were enveloped in a Nd rich grain boundary phase, and they produced unordinary heterostructures. The exchange bias behavior on the permanent magnet Nd–Fe–B was investigated at 5 K. The temperature dependence of magnetization measurement found spin-reorientation transition in the vicinity of temperature T = 100 K. When temperature under 100 K, ferromagnetic property played a major role with frozen magnetic moment. The coercivity at 5 K was larger but the negative saturated magnetic moments was lower compared to that at room temperature. In the magnetic hysteresis (M–H) loops at 5 K to 50 K, the negative shift of H and the positive shift of M along axis increased sharply with the temperature drops. The training effect was observed due to the existence of frozen spin moment. The exchange bias could be ascribed to minor loop effect and unidirectional anisotropy with spin-reorientation transition.

The PI3K/Akt Cascade Is Involved in the Antidiabetic Effect of Compound GSB-214, a Low-Molecular-Weight BDNF Mimetic.

In our previous studies on the streptozotocin model of diabetes we hypothesized that activation of the PI3K/Akt signaling pathway is essential for the realization of the antidiabetic effect of low-molecular-weight NGF and BDNF mimetics. Here we analyze the effect of a specific PI3K/Akt pathway inhibitor (LY 294002) on the antidiabetic effect of the BDNF loop 1 mimetic GSB-214. The experiments on C57BL/6 mice with streptozotocin-induced diabetes showed that GSB-214 attenuated the hyperglycemic effect of streptozotocin and prevented weight loss typical of diabetes, while LY 294002 eliminated these effects of GSB-214. These findings clearly demonstrate the involvement of PI3K/Akt pathway in the implementation of the effects of this low-molecular-weight BDNF mimetic.

Numerical Study on the Effect of Mean Pressure and Loop's Radius to the Onset Temperature and Efficiency of Traveling Wave Termoacustic Engine

The thermoacoustic engine can be a device to convert waste heat energy in the engine car become useful energy such as for charging battery in car or Air conditioner of the car. This work can be done by experimentally and numerically. There are some parameters that have an impact on the performance of the engine. They are geometry of the engines, working fluid, and mean pressure. The performance of the engine depends on the efficiency and the heating temperature. In the car, waste heat energy is not high enough. Therefore, we need to utilize the low heating temperature to be converted into useful energy. This study contributes to numerically the effect of mean pressure and loop’s radius of the regenerator on the onset temperature and the efficiency of traveling wave thermoacoustic engines. The application that is used to solve numerical problems is fortran95. There are two codings that are used in fortran95. They are stability limits and efficiency codes. The lowest onset temperature that achieved is 153˚C with efficiency up to 38.1% that can be reached when the mean pressure is 4.0 MPa and the loop's radius is 5 cm. This result indicated that we can use low heating temperatures from waste heat of engine car to turn on electronics equipment inside the car.

Prefiltered Synchronization Structure for Grid-Connected Power Converters to Reduce the Stability Impact of PLL Dynamics

Grid-connected converters under weak grid conditions could present instabilityassociated with the synchronization elements and not directly with the current control loop. The impedance-based stability criterion is an effective tool to address the problem. To solve the negative effect of the synchronous reference frame phase-locked loop (SRF-PLL) on grid current control under weak grid conditions, a synchronization structure with prefilter, based on a filtered quadrature signal generator (FQSG), is proposed in this article to improve the dynamics of the controller’s performance. The small-signal impedance model, implemente as a multiple-input multiple-output system in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -frame, characterizes the effect of the FQSG-PLL dynamics on the current control loop. From it, the impedance-based analysis shows the reduction of the stability issues of the converter. The analysis results were verified by time-domain simulations and by experimental tests in a full-scale 2-MW converter test bench.

Effects of a band loop on muscle activity and dynamic Knee valgus during pedaling

BackgroundChange in the lower extremity alignments in the frontal plane and muscle activation patterns have been associated with lower extremity injuries. Therefore, to prevent injuries, many therapeutic protocols focus on find ways to correct dynamic knee valgus (DKV). MethodsThirty-one recreational male cyclists with DKV (26.4 ± 4.5 years, 176.63 ± 7.51 cm, 75.81 ± 9.29 kg, 23.20 ± 4.15 kg/m2) volunteered to participate in this study. Simultaneous recordings of kinematic and electromyography data were performed on ten consecutive pedal cycles which began during the last 30 seconds of each four test condition: with band at 0.5 kg workload, with band at 2 kg workload, without band at 0.5 kg workload, and without band at 2 kg workload. The paired t-test was used for statistical analysis (p < 0.05). ResultsThe results indicated significant differences in VM (band = 0.029, no band = 0.031) and VL (band = 0.015, no band = 0.035) activation between workloads in each condition. Also there were significant differences in Gmed activation (0.5kg = 0.001, 2kg = 0.037), onset of Gmed (0.5kg = 0.048, 2kg = 0.012), offset of Gmed (0.5kg = 0.048, 2kg = 0.015), TFL activation (0.5kg = 0.001, 2kg = 0.041) and offset of TFL (0.5kg = 0.078, 2kg = 0.005) between the band and no band conditions. There was no different significant in VM/VL ratio between in each of four testing conditions (p > 0.05). The Gmed/TFL ratio was significantly greater in band condition than no band at both 0.5 (p = 0.045) and 2 kg (p = 0.001) workload. Knee abduction angle was affected by the band loop during the pedaling at two different workloads (0.5 kg: p = 0.047, 2 kg: p = 0.021) but mean (p = 0.027) and peak (p = 0.033) knee abduction angle significantly increased with increasing workload during the pedaling with band loop. Conclusionspedaling with the band loop can be considered as an effective method to increase the Gmed, Gmed/TFL ratio and control of DKV but increasing the workload during pedaling must be done with caution to prevent DKV.

Umbilical cord characteristics and their association with adverse pregnancy outcomes: A systematic review and meta-analysis.

Current data on the role of the umbilical cord in pregnancy complications are conflicting; estimates of the proportion of stillbirths due to cord problems range from 3.4 to 26.7%. A systematic review and meta-analysis were undertaken to determine which umbilical cord abnormalities are associated with stillbirth and related adverse pregnancy outcomes. MEDLINE, EMBASE, CINAHL and Google Scholar were searched from 1960 to present day. Reference lists of included studies and grey literature were also searched. Cohort, cross-sectional, or case-control studies of singleton pregnancies after 20 weeks' gestation that reported the frequency of umbilical cord characteristics or cord abnormalities and their relationship to stillbirth or other adverse outcomes were included. Quality of included studies was assessed using NIH quality assessment tools. Analyses were performed in STATA. This review included 145 studies. Nuchal cords were present in 22% of births (95% CI 19, 25); multiple loops of cord were present in 4% (95% CI 3, 5) and true knots of the cord in 1% (95% CI 0, 1) of births. There was no evidence for an association between stillbirth and any nuchal cord (OR 1.11, 95% CI 0.62, 1.98). Comparing multiple loops of nuchal cord to single loops or no loop gave an OR of 2.36 (95% CI 0.99, 5.62). We were not able to look at the effect of tight or loose nuchal loops. The likelihood of stillbirth was significantly higher with a true cord knot (OR 4.65, 95% CI 2.09, 10.37). True umbilical cord knots are associated with increased risk of stillbirth; the incidence of stillbirth is higher with multiple nuchal loops compared to single nuchal cords. No studies reported the combined effects of multiple umbilical cord abnormalities. Our analyses suggest specific avenues for future research.

Opposite Effects of Flexible Single-Stranded DNA Regions and Rigid Loops in DNAzyme on Colloidal Nanoparticle Stability for "Turn-On" Plasmonic Detection of Lead Ions.

Strains in biomolecules greatly restrict their structural flexibility. The effects of DNA's structural flexibility on nanoparticle stability have remained less explored in the field of plasmonic biosensors. In the present study, we discover the opposite effects of a rigid loop and a flexible single-stranded DNA (ssDNA) region in DNAzyme on the colloidal stability of gold nanoparticles (AuNPs), which afford "turn-on" plasmonic detection of Pb2+. In specific, DNAzyme-functionalized AuNPs undergo spontaneous assembly at high ionic strength upon hybridization to their substrate sequence because of a DNA base stacking interaction. In the presence of Pb2+, however, the DNAzyme grafted on the AuNP cleaves the substrate and forms an ssDNA region in the middle of the rigid loop. The induced structural flexibility of the surface-grafted DNAzyme by the ssDNA region in the middle helps elevate interparticle entropic repulsion, thereby bringing AuNP assemblies back to dispersion. We discover that this process can afford a dramatic increase of the AuNPs' plasmon resonance for determination of Pb2+ concentration. Under optimized conditions, a detection limit of 8.0 nM can be achieved for Pb2+ by this method with high selectivity. Its applicability to Pb2+ analysis in tap water samples has also been demonstrated.

Clustering of cosmic string loops

Observational effects of cosmic string loops depend on how loops are distributed in space. Chernoff [1] has argued that loops can be gravitationally captured in galaxies and that for sufficiently small values of Gμ their distribution follows that of dark matter, independently of the loop's length. We re-analyze this issue using the spherical model of galaxy formation with full account taken of the gravitational rocket effect—loop accelerated motion due to asymmetric emission of gravitational waves. We find that only loops greater than a certain size are captured and that the number of captured loops is orders of magnitude smaller than estimated by Chernoff.

General Regularities and Differences in the Behavior of the Dynamic Magnetization Switching of Ferrimagnetic (CoFe2O4) and Antiferromagnetic (NiO) Nanoparticles

In antiferromagnetic (AFM) nanoparticles, an additional ferromagnetic phase forms and leads to the appearance in AFM nanoparticles of a noncompensated magnetic moment and the magnetic properties typical of common FM nanoparticles. In this work, to reveal the regularities and differences of the dynamic magnetization switching in FM and AFM nanoparticles, the typical representatives of such materials are studied: CoFe2O4 and NiO nanoparticles with average sizes 6 and 8 nm, respectively. The high fields of the irreversible behavior of the magnetizations of these samples determine the necessity of using strong pulsed fields (amplitude to 130 kOe) to eliminate the effect of the partial hysteresis loop when studying the dynamic magnetic hysteresis. For both types of the samples, coercive force HC at the dynamic magnetization switching is markedly higher than HC at quasi-static conditions. HC increases as the pulse duration τP decreases and the maximum applied field H0 increases. The dependence of HC on field variation rate dH/dt = H0/2τP is a unambiguous function for CoFe2O4 nanoparticles, and it is precisely such a behavior is expected from a system of single-domain FM nanoparticles. At the same time, for AFM NiO nanoparticles, the coercive force is no longer an unambiguous function of dH/dt, and the value of applied field H0 influences more substantially. Such a difference in the behaviors of FM and AFM nanoparticles is caused by the interaction of the FM subsystem and the AFM “core” inside AFM nanoparticles. This circumstance should be taken into account when developing the theory of dynamic hysteresis of the AFM nanoparticles and also to take into account their practical application.

Future lepton collider prospects for a ubiquitous composite pseudoscalar

Composite Higgs models feature new strong dynamics leading to the description of the Higgs boson as a bound state arising from the breaking of a global (flavour) symmetry. These models generally include light states generated by the same dynamics, the detection of which may present the first observable signs of compositeness. One such state is a pseudo-scalar boson resulting from the breaking of a $U(1)$ symmetry common to most composite setups, and whose hints are expected to be visible through low-mass resonance searches at present and future hadron and lepton colliders. In this work we study the phenomenology of this pseudo-scalar field. We show that, for a light state, bottom quark loop effects dominantly impact the production cross section and considerably modify the decay pattern. Moreover, we make a case for targeted low-mass analyses at future lepton colliders, with an emphasis on high-luminosity machines aiming to operate at low centre-of-mass energies. We present a simplified outline of a search for this light pseudo-scalar at one such machine, considering electron-positron collisions at the $Z$-pole. We focus on a signature arising from the pseudo-scalar decay into a pair of hadronic taus and a production mode association with a pair of leptons of opposite electric charges, and compare cut and count methods with machine learning methods.

Comparative study of two types of control loops aiming at trajectory tracking of a steer-by-wire system with Coulomb friction

In an era of automated driving, steer-by-wire system seems to be an indispensable component for an autonomous vehicle. Among the many problems concerned, steering control of the system may be arguably the most indispensable part that lay the foundation for the system and is essentially a position servo control problem. Traditionally, the most commonly used control loop structures of the position servo system can be classified into two categories, both considering the current control loop as an essential part. However, this is not necessarily true in practical applications. In view of this, control systems with two different types of control loops based on proportional–integral–derivative controllers have been designed and compared in this paper for trajectory tracking of the steer-by-wire system with Coulomb friction. The aim is to explore the essential differences between the two types of control loops and study the effect of current loop on performance of the system. When properly designed, it can be seen that the asymptotic stability of the control system can be guaranteed. However, the system with type I control loop has a faster response speed, whereas the system with type II control loop has a smoother response. Theoretical as well as simulation and experimental results have been provided in detail, which can contribute to the understanding of the two types of control loops and can be used as guidance not only for researchers but also for engineering practice.

Anomalous dynamics on the ergodic side of the many-body localization transition and the glassy phase of directed polymers in random media

Using the non-interacting Anderson tight-binding model on the Bethe lattice as a toy model for the many-body quantum dynamics, we propose a novel and transparent theoretical explanation of the anomalously slow dynamics that emerges in the bad metal phase preceding the Many-Body Localization transition. By mapping the time-decorrelation of many-body wave-functions onto Directed Polymers in Random Media, we show the existence of a glass transition within the extended regime separating a metallic-like phase at small disorder, where delocalization occurs on an exponential number of paths, from a bad metal-like phase at intermediate disorder, where resonances are formed on rare, specific, disorder dependent site orbitals on very distant generations. The physical interpretation of subdiffusion and non-exponential relaxation emerging from this picture is complementary to the Griffiths one, although both scenarios rely on the presence of heavy-tailed distribution of the escape times. We relate the dynamical evolution in the glassy phase to the depinning transition of Directed Polymers, which results in macroscopic and abrupt jumps of the preferred delocalizing paths when a parameter like the energy is varied, and produce a singular behavior of the overlap correlation function between eigenstates at different energies. By comparing the quantum dynamics on loop-less Cayley trees and Random Regular Graphs we discuss the effect of loops, showing that in the latter slow dynamics and apparent power-laws extend on a very large time-window but are eventually cut-off on a time-scale that diverges at the MBL transition.

Admittance-Based Stability Comparative Analysis of Grid-Connected Inverters With Direct Power Control and Closed-Loop Current Control

Direct power control (DPC) is widely used in grid-connected inverters. First, considering the effects of phase-locked loop (PLL), voltage outer loop, power inner loop, control delay, and frequency coupling, a broadband admittance model of the grid-connected inverter with DPC is established. The admittance characteristics of grid-connected inverters with DPC and closed-loop current control (CCC) are compared and analyzed. Due to the different inner loop control objects, the components produced by the power calculation in DPC and the Park's transformation in CCC cause the admittance differences between the grid-connected inverters with DPC and CCC. Then, the effects of grid impedance, output power, and control parameters on system stability are analyzed. It is revealed that the stability of the grid-connected inverter with DPC is very sensitive to grid impedance and easily affected by output power and inner loop bandwidth, while the grid-connected inverter with CCC has a better adaptability to weak grid, high output power, and inner loop bandwidth. Moreover, the PLL bandwidth has little effect on the stability of the grid-connected inverter with DPC, but has a great impact on the stability of the grid-connected inverter with CCC when the inverter is connected to weak grid. Finally, the correctness of the analysis is verified by experiments.

Energy management with improved frequency sharing based control for battery/ultracapacitor hybrid energy system in the presence of delay

Hybrid energy storage system (HESS) consists of different electrical storage devices with complementary characteristics to satisfy both the energy and power requirements of the load. This study presents an improved frequency sharing algorithm for battery/ultracapacitor (UC) HESS in the presence of delay. Time delay is inevitable with the digital implementation of control algorithms. Presence of delay deteriorates the transient response of the system by limiting the bandwidth of inner current loops. The DC-link voltage will settle only after settling of the slower loop, i.e. battery loop, hence the presence of delay will make the system response slower in conventional methods. However, the improved algorithm shares battery current loop error during transients with faster UC current loop and hence DC-link voltage settling becomes faster. Furthermore, for safe and efficient operation, an energy management algorithm (EMA) has been designed that ensures nominal UC voltage and other operational constraints as described in the study. To analyse the effect of UC voltage control loop on the operation of the DC-link voltage control loop during transients, UC voltage control loop with different bandwidths have been designed and tested. Microcontroller based implementation was done for experimental verification of the improved control algorithm and EMA.

The Effect of Band Loop on Kinematic and Electromyography of Lower Extremities during Pedaling with Ergometer in Male Students with Genuvarum: A Descriptive Study

The Effect of Band Loop on Kinematic and Electromyography of Lower Extremities during Pedaling with Ergometer in Male Students with Genuvarum: A Descriptive Study

Experimental study of a natural circulation loop and RELAP5-3D analysis

Passive safety systems, which are being largely adopted in advanced nuclear reactors to enhance the safety of the plant, are often based on natural circulation for the decay heat removal and are characterized by the presence of non-condensable gases and pools with stagnant liquid at atmospheric pressure. At the Energy Department of Politecnico di Torino (Italy), the test facility PROPHET has been designed and operated with water in both single-phase and two-phase flow. It consists of a bayonet heat exchanger electrically heated at constant power, a condenser immersed in a pool containing a fixed initial mass of water and the connecting pipes. The effect of loop filling ratio and condenser shell-side level on the system behaviour are here studied. The experimental transients have been analysed in terms of phenomenological windows. Heat losses and the heat sink influence both the time behaviour and the final values of pressure and temperatures in the facility; the filling ratio determines the kind of natural circulation (single-phase or two-phase) and strongly affects the phenomena occurring during the experiments. The experimental results are also compared with the predictions of a RELAP5-3D model. Discrepancies between calculated and experimental values are estimated during the transients in order to evaluate the code prediction capabilities.