Combination Of Switching Research Articles

Magnetization dynamics and domain reversal in electrodeposited permalloy thin films: impact of thickness and annealing treatment

The domain reversal and magnetization dynamics of electrodeposited permalloy (Fe20Ni80) thin films on conducting ITO/glass substrate was investigated using Magneto-optic Kerr effect microscopy and ferromagnetic resonance. Permalloy thin films were electrodeposited with thickness ranging from 66 nm to 330 nm. Synchrotron XRD confirmed the deposited permalloy in FCC phase without any impurity. The squared hysteresis with very low coercivity (Hc ∼ 5 Oe) established soft magnetic nature of the films. Further, angular MOKE hysteresis measurements with simultaneous domain imaging revealed four-fold surface anisotropy in as-deposited film ensuing magnetization reversal via branched and ripple domains. The annealing treatment in Ar+H2 atmosphere removed surface anisotropy and renovated the magnetization reversal through 180° branched domains with rapid magnetization switching. Ferromagnetic resonance spectroscopy discloses reduction in the gyromagnetic ratio (γ) as well as in Gilbert damping parameter (α) as the film thickness increases. The lowest Gilbert damping for 330 nm film measured at 0.022, which further reduced to 0.018 after annealing. The combination of rapid magnetization switching and low Gilbert damping in the electrodeposited permalloy thin films render them promising for implementation in high-frequency microwave devices devices and magnetic sensors.

Distribution Network Reconfiguration in Effective Presence of DGs, EVCSs and DRP: A Novel Multi-Objective Approach

By determining the ideal combination of switch on/off status, distribution network reconfiguration (DNR), a critical operational problem in distribution systems, has been employed to increase system efficiency. Additionally, benefits such as improved voltage profiles and loss reduction through reactive power compensation are provided by placing capacitors in the distribution network optimally. Thus, this study formulates multi-objective DNR with optimal allocation of distributed generators (DGs), electric vehicles charging stations (EVCSs) and capacitors. Additionally, the demand response programme (DRP) is employed to enhance the distribution system’s operation performance. Losses and voltage variation, which are significant objectives for conventional distribution systems, are typically the focus of the DNR problem. Modern distribution systems’ security concerns caused by DGs that could jeopardize power system security have been all but ignored in terms of the issue of power system operation. As a result, the primary objective of this study is to address the DNR issue in order to increase reliability. This study specifies the energy not provided (ENS) in order to do this. This work uses a modified shuffled frog leaping algorithm (MSFLA), which benefits from a novel mutation technique, to reduce processing time and improve solution quality, in particular to avoid becoming stuck in local optima. To evaluate the efficiency and adaptability of the suggested method, it is applied to three distribution systems, comprising 33, 69, and 86-node test networks. After that, the outcomes are contrasted with those of various approaches. Power loss and ENS are reduced by around 45% and 5.5%, respectively, by executing the suggested strategy on a 33-node test system compared to the initial value before the DNR.

Investigating the impact of diameters and thread designs on the Biomechanics of short implants placed in D4 bone: a 3D finite element analysis

BackgroundDental implants emerge as a dependable and efficacious alternative for patients experiencing partial or complete tooth loss. The stability of these implants is influenced by surface topography and macro-level design. In cases where the height of the maxillary posterior region is diminished, employing short implants can prove advantageous. With the aim of examining the distribution of von Mises stress, strain, and micromovement in D4 bone quality surrounding platform-switched short implants, measuring 6 mm in length and featuring diameters ranging from 4 to 6 mm, as well as different thread designs, an in-depth finite element analysis was conducted under immediate loading conditions. MethodologyA 3D finite element model was constructed to simulate maxillary molar crowns, incorporating an implant with a length of 6 mm and varying diameters and thread designs. The diameters utilized were 4/3.6 mm, 5/4 mm, and 6/4.8 mm, while the thread designs included buttress, square, and triangle patterns. Each model underwent analysis with a 100 N force applied in two directions: vertical and oblique, relative to the long axis of the implant. Stress, strain, and micromovement in the peri-implant region were recorded, employing the Ansys Workbench R v.18.1 software for modelling and analysis.ResultsWhen comparing all three diameters, the wide diameter (6 mm threads) exhibited the lowest values of peri-implant von Mises stresses (3.3 MPa and 35.1 MPa), strains (194 Ɛ and 484 Ɛ), and micromovements (0.7 μm and 1.3 Ɛ) subjected to axial and non-axial loading of a 100 N force. Notably, square microthreads yielded the most favorable stress parameters among the different thread shapes, manifesting the minimum values of stress, strains, and micromovements in their vicinity.ConclusionFor the treatment of atrophic ridges or in scenarios necessitating extensive surgical preparation of the implant site, a combination of short implants, wide diameters, and platform switching can be employed. In situations with reduced bone height and the requirement for an implant-supported prosthesis to replace a missing permanent maxillary molar, the utilization of wide-diameter platform-switched short implants measuring 6 mm in length, featuring a square thread design, should be taken into consideration.

Interfaces generation via severe plastic deformation – A new way to multiple shape memory polymer composites

Shape memory materials are classically described as a combination of switching and permanent domains for shape switching and shape recording, respectively. It is assumed that the interfaces between immiscible polymers could play a dual role - switching and permanent structural elements. In this work, we use severe plastic deformation as a method providing the formation of the interphases during the integration of thermodynamically immiscible polymers. By severe plastic deformation a composite gets much richer in interfaces than that obtained by melt blending. It can be used to produce effective multi-shape memory composites. A pair of immiscible polymers - acrylonitrile-butadiene-styrene copolymer (ABS) and poly(ethylene terephthalate) (PET) subjected to severe plastic deformation resulted in ABS/PET composite rich in interfaces with a broad glass transition. Strong plastic deformation by equal channel multi-angle extrusion resulted in the formation of large amount of intimate contact layers of ABS and PET and in strain-induced PET crystallization. Thermomechanical programming of such material rich in interfaces enabled a dual and triple shape memory with exceptional parameters.

Evaluation of Neural Network Verification Methods for Air-to-Air Collision Avoidance

Neural network approximations have become attractive to compress data for automation and autonomy algorithms for use on storage-limited and processing-limited aerospace hardware. However, unless these neural network approximations can be exhaustively verified to be safe, they cannot be certified for use on aircraft. An example of such systems is the unmanned Airborne Collision Avoidance System (ACAS) Xu, which is a very popular benchmark for open-loop neural network control system verification tools. This paper proposes a new closed-loop extension of this benchmark, which consists of a set of 10 closed-loop properties selected to evaluate the safety of an ownship aircraft in the presence of a co-altitude intruder aircraft. These closed-loop safety properties are used to evaluate five of the 45 neural networks that comprise the ACAS Xu benchmark (corresponding to co-altitude cases) as well as the switching logic between the five neural networks. The combination of nonlinear dynamics and switching between five neural networks is a challenging verification task accomplished with star-set reachability methods in two verification tools. The safety of the ownship aircraft under initial position uncertainty is guaranteed in every scenario proposed.

Design and Implementation of Automatic Switching for Water Level Control of Community Water Supply

This paper presents design and implementation of Automatic Switching for controlling the water level in the reservoir of community water supply. The water supply system is energized by 2 sources i.e. power from utility grid and power generated by photovoltaic panels equipped with energy storage. The switching is based on the reservoir water level and determines the operation of submersible pump. The switching system employs electrode sensors in the water control level where 3 conditions are considered to control motor that drives the pump. The Automatic Switching is connected to Automatic Transfer Switch (ATS) that selects power sources to energize the pump, where it may be from the solar PV supported by storage system or from the grid. The selection is based on the remaining energy saved in the storage, when it is sufficient then it is used to energize the pump. Otherwise, the power from the grid is used to supply the pump. The combination of Automatic Switching and ATS determines when the pump is on and which power is taken to supply the pump. The manual system is complemented in the switching system to enable manual operation when the automatic system fails to work for some reason. The whole system is developed in a panel for easy operation and monitoring. The water level indicator is given in the panel for the purpose of adjusting the pump operation based on water level in the reservoir.

Development of a Hybrid Fault Current Limiter Using Liquid Metal for Large Capacity MVdc Power Systems

A hybrid fault current limiter (FCL) for medium voltage direct current (MVDC) power systems is introduced in this paper. It achieves low operation loss and high current limiting resistance through the combination of a fast mechanical switch, a magnetic induction module and a number of liquid metal units (LMUs). Firstly, the parameters of the magnetic induction module are designed to achieve a desired fault current commutation process. Then, the working principle of LMU is introduced, and its resistance properties corresponding to the liquid metal arc are studied in detail. Equations are deduced to model the V-I characteristic of LMU. Thus the current limiting performance of the topology can be simulated. To verify the feasibility of the FCL, a 5-kV/5-kA prototype is developed and laboratory tests are implemented. Comparisons with other FCLs are also conducted to demonstrate the advantages of the proposed one. It is concluded that the prototype provides the basis for further commercial product development.

Evaluation of a cardiac troponin process flow at the chest pain center with the shortest turnaround time.

BackgroundEarly diagnosis of myocardial infarction is crucial in chest pain management and cardiac troponin (cTn) test is an important step in it. Process improvement to shorten the test turnaround time (TAT) may improve patients’ outcomes. The cTn test at chest pain center (CPC) of Zhongshan Hospital had the shortest TAT ever reported, but its process flow was not fully evaluated.MethodsWe performed a stepwise evaluation of CPC cTn TAT and explored the potential factor that might cause delay. The performance of CPC cTn test was also compared with cTn test and human chorionic gonadotropin (HCG) test ordered from emergency department (ED).ResultsAt least 95% of CPC cTn tests were completed in 60 min, while 62% in 30 min. The medians of monthly order‐to‐collect time, collect‐to‐received time, and received‐to‐result time were ~7 min, ~3 min, and ~13 min, respectively. The samples collected at the bedside had longer collect‐to‐received time than the ones collected at the blood draw site next to the laboratory. Compared to ED cTn test and ED HCG test, CPC cTn test took less time in each step. A combination of the sample type switch and the centrifugation time reduction contributed the most to the shortening of TAT, which was reflected in the received‐to‐result time.ConclusionsThe current process flow of CPC cTn test satisfied the requirements of chest pain management, giving an example of how to implement process improvement for emergency medicine to shorten TAT of laboratory tests.

A Repetitive Low Impedance High Power Microwave Driver

A low impedance high power microwave (HPM) driver is designed, which can be used in studying multi-gigawatt HPM devices such as the magnetically insulated transmission line oscillator (MILO), based on a helical pulse forming line (PFL) and the Tesla pulse transformer technology. The co-axial PFL is insulated by ethanol–water mixture, whose dielectric constant can be adjusted; and the helical line increases the output pulse width as well as the impedance to make a better match with the load. By the optimal combination of PFL charging voltage and output switch working voltage, the reliability of the PFL can be improved. The Tesla transformer has partial magnetic cores to increase the coupling coefficient and is connected like an autotransformer to increase the voltage step-up ratio. The primary capacitor of the transformer is charged by a high voltage constant current power supply and discharged by a triggered switch. A transmission line is installed between the PFL and the HPM load, to further increase the load voltage. A ceramic disk vacuum interface is used for improving the vacuum of the HPM tube. The experiments show that the driver can operate at 30 GW peak power, 75 ns pulse width and 5 Hz repetition rate.

Influence of magnetic fields on ultrafast laser-induced switching dynamics in Co/Gd bilayers

Recently it has been shown that not only GdFeCo alloys exhibit single-pulse helicity-independent all-optical switching, but that this effect is also seen in Co/Gd bilayers. However, there have been no reports on the explicit time dynamics of the switching process in these bilayers as of yet. Furthermore, time-resolved measurements of switching of other materials are typically done with a constant applied field to reset the magnetization between consecutive pulses and thus ensure repeatable behavior. In this paper we experimentally resolve the explicit dynamics of the switching process in Co/Gd, and the influence of applied magnetic fields on the switching process. We observe that after a switch within several picoseconds, the magnetization switches back at a time scale of hundreds of picoseconds. This backswitch includes a strong dependence on the magnetic field strength even at subtesla fields, significantly smaller than the exchange fields that govern the switching dynamics. This surprising behavior is explained by a combination of longitudinal switching (on a picosecond timescale), precessional switching (on a nanosecond time scale), and domain-wall motion (on a timescale of $10\phantom{\rule{0.16em}{0ex}}\mathrm{n}\mathrm{s}$ and beyond). We discuss these different switching regimes and their relative importance using simple model calculations.

Acidic microenvironment triggered in situ assembly of activatable three-arm aptamer nanoclaw for contrast-enhanced imaging and tumor growth inhibition in vivo.

Rationale: Static assembled multivalent DNA nanotheranostics system have encountered some bottleneck problems in cancer imaging and therapy, such as poor penetration and high immunogenicity. Herein, we proposed an acidic tumor microenvironment triggered assembly of activatable multivalent nanodevice, called “three-arm aptamer nanoclaw” (TA-aptNC), assembled from three pH-responsive aptamer-decorated DNA monomers (pH-aptDMs) to facilitate their functions of imaging and therapy.Methods: The activated TA-aptNC was constructed by acidic microenvironment triggered in situ assembly of three pH-aptDMs. Designer pH-aptDM was established based on the combination of a pH-responsive i-motif switch and an assembly module with a cell membrane anchoring aptamer ligand. Acidic microenvironment-triggered the assembly of the TA-aptNC was characterized by electrophoresis and atomic force microscopic (AFM). The binding affinity and stability of the TA-aptNC, comparing the monovalent pH-aptDM, were studied via the flow cytometry and nuclease resistance assays. Acidic microenvironment-activated contrast-enhanced tumor imaging and significantly antitumor efficiency were evaluated in vitro and in vivo.Results: At physiological pH environment, the pH-aptDMs with excellent tissue permeability exited as inactivated and monodispersed small monomer. When encountering acidic microenvironment at the tumor site, pH-responsive i-motif switch liberated from the pH-aptDMs, and the three unconstrained DNA modules (DM1, DM2 and DM3) subsequently assembled in situ into the TA-aptNC. Compared with monovalent pH-aptDMs, the spontaneously formed activatable TA-aptNC afforded 2-fold enhanced binding ability via the multivalent effect, which further facilitated the selective tumor cell uptake capability, thus enabling a contrast-enhanced tumor imaging and significantly antitumor efficiency in vivo without systemic toxicity.Conclusions: The proposed strategy offers valuable insight into excavating an endogenous stimuli-triggered assembly of multivalent nanodevice for accurate diagnosis and efficient tumor therapy.

Giant strain responses and relaxor characteristics in lead-free (Bi0.5Na0.5)TiO3–BaZrO3 ferroelectric thin films

A giant macro-scale strain value of 1.31% was obtained in the BNT-4BZ thin films, which is determined by the combination of domain switching and reversible electric-field-induced phase transitions between relaxor state and ferroelectric phase.

Polymorph acceptor-based triads with photoinduced TADF for UV sensing

In contrast to many donor–acceptor type organic luminophores exhibiting thermally activated delayed fluorescence (TADF), two deep blue TADF emitters designed in this work contain only typical electron accepting moieties with different electron accepting abilities. Derivatives of benzophenone and diphenylsulfone substituted with phenothiazine-5,5-dioxide donor moieties were synthesized and studied. In addition to the TADF, green to blue emission color switching and strong fluorescence intensity enhancement by more than 60 times was detected for THF solution of the derivative of phenothiazine-5,5-dioxide and benzophenone under increase of UV excitation dose. We proved by a variety of experimental and theoretical studies that the unusual photophysical properties of the derivative of benzophenone are mainly related to the formation of different conformers. The photostimulated intensity enhancement of the compound is due to the rise of the quantity of triplet states and their further crossing to singlet states. To our knowledge, this is the first observation of a combination of photoinduced color switching and triplet-dependent emission intensity enhancement. These properties are shown to be useful for UV sensing with very low detection limits (less than 10 μW/cm2 for the toluene solution). Under gradual increase of UV excitation dose, the DMF solution demonstrated a green → blue color swishing from (0.34; 0.44) to (0.17; 0.18) of CIE coordinates that can be detected by naked eye.

Ionic Liquid Electrolyte-Based Switchable Mirror with Fast Response and Improved Durability.

Electrochemically tunable devices based on reversible metal electrodeposition have attracted extensive attention for energy-saving smart windows, information displays, digital signage, and variable reflectance mirrors, owing to their excellent optical modulation characteristics, low operation voltage, and superb electrochemical stability. Here, we study the effects of ionic liquid (IL)-based electrolytes on electrodeposition of the reversible electrochemical mirrors (REMs) by changing the organic cations of the ILs to obtain devices with the desired spectroelectrochemical and electrodeposited properties. Spectroelectrochemical measurements and scanning electron microscopy images show that organic cations drastically affect the switching speed and cycling durability, which we proposed on the basis of the difference in the absorption energies between cations and Ag(111) surfaces. Higher adsorption energy indicates strong adhesion between organic cations and Ag(111) surfaces, and this strong adsorption would prevent aggregation and agglomeration during the nucleation of Ag nanoparticles (AgNPs), leading to a denser and more compact electrodeposited Ag film and faster switching speeds (3.3 s for coloring and 14.3 s for bleaching). These findings allow us to fabricate dynamic devices that exhibit reversibly switchable light modulation at fast switching speeds and excellent cycling stability over thousands of cycles without attenuation. The combination of rapid switching and durable cycling stability enables tunable windows, which are based on reversible electrodeposition of metal Ag and IL-based electrolytes, make REM devices a competitive and promising alternative to traditional intelligent response materials.

Speaker Verification from Codec-Distorted Speech Through Combination of Affine Transform and Feature Switching

Speaker Verification from Codec-Distorted Speech Through Combination of Affine Transform and Feature Switching

Fabrication of Oriented n‐Type Thermoelectric Polymers by Polarity Switching in a DPP‐Based Donor–Acceptor Copolymer Doped with FeCl3

Abstractn‐Type‐doped polymers are key elements to fabricate all‐polymer thermoelectric generators but they are challenging to produce. Herein, a new strategy is proposed, which is based on polarity switching upon doping of a donor–acceptor (D–A) copolymer based on diketopyrrolopyrrol (DPP) and quintethiophene (5T) with FeCl3. Polarity switching from p‐type to n‐type is observed upon increasing the doping concentration of FeCl3. An analysis based on nonmonotonic density of states is proposed, which accounts for the main experimental trends and demonstrates that the polarity switch is governed by the electronic band filling that is determined by the dopant concentration. The influence of the curvature of the density of states is in addition discussed and a complete description of the doping induced transport regimes is proposed. This polarity switching depends on the molecular weight Mn of the polymer and shifts to higher FeCl3 concentrations with increasing Mn. This behavior is attributed to the change of the width of the density of states with Mn. The combination of polarity switching and alignment is a means to produce n‐type‐like oriented and conducting polymers with enhanced power factors up to 10 µW K−2 m−1 along the chain direction.

Large‐Scale and Robust Multifunctional Vertically Aligned MoS2 Photo‐Memristors

AbstractMemristive devices have drawn considerable research attention due to their potential applications in non‐volatile memory and neuromorphic computing. The combination of resistive switching devices with light‐responsive materials is considered a novel way to integrate optical information with electrical circuitry. On the other hand, 2D materials have attracted substantial consideration, thanks to their unique crystal structure, as reflected in their chemical and physical properties. Although not the major focus, van der Waals solids are proven to be potential candidates in memristive devices. In this scheme, the majority of the resistive switching devices are implemented on planar flakes, obtained by mechanical exfoliation. Here a facile and robust methodology is utilized to grow large‐scale vertically aligned MoS2 (VA‐MoS2) films on standard silicon substrates. Memristive devices with the structure silver/VA‐MoS2/Si are shown to have low set‐ON voltages (<0.5 V), large‐retention times (>2 × 104 s), and high thermal stability (up to 350 °C). The proposed memristive device also exhibits long term potentiation/depression (LTP/LTD) and photo‐active memory states. The large‐scale fabrication, together with the low operating voltages, high thermal stability, light‐responsive behavior, and LTP/LTD, make this approach very appealing for real‐life non‐volatile memory applications.

The application of combined Markov regime switching and volatility model in detecting early financial crisis in Indonesia

The financial crisis had occurred in Indonesia in the middle of 1997 to 1998 which caused the economy of Indonesia was down suddenly. Because the crisis occurred suddenly and even unexpectedly, the Indonesian government was not ready to deal with it. Therefore, the Indonesian government needs a system that can detect crisis signals; so that, such a financial crisis can be avoided. Export and import indicators have high fluctuation and regime-changing during a crisis so that they also can be used to detect crisis signals. The volatility model is able to explain the volatility which included in the indicators, while the Markov regime switching model can explain the regime-changing. Furthermore, a method that can be used to detect a crisis is the combination of Markov regime switching and volatility model. The value of smoothed probability obtained from the combination of those models is able to detect the financial crisis in Indonesia. The results show that export and import indicators can be modelled successively using MRS-GARCH (2,1,1) and MRS-ARCH (2,1). The results obtained from the prediction of those two models show that there is no financial crisis signal in Indonesia for a year later.

Financial crisis prediction in Indonesia using combined of volatility and Markov switching models based on real interest rate on deposit and nominal exchange rate indicators

The financial crisis has happened Indonesia 1997 and 2008. The crisis had brought the disadvantages impact on the economy of Indonesia. To anticipate the impact of the crisis, an early detection system that can detect some signs of a financial crisis is needed so that the government as a decision maker in maintain the stability of the economy. The crisis occurred due to hight volatility and structural changes in macroeconomic indicators. One of model that can be used to captured signals crisis is a combination of volatility and Markov switching. Fluctuations can be explained using volatility model, while some changes in conditions are explained through Markov switching. This study uses indicators of the real interest rate on deposit and nominal exchange rate to detect signals crisis in Indonesia. The results showed that the MS-ARCH(2,1) models of the real interest rate on deposit could only explain the crisis that occurred in 1997 and the MS-GARCH(3,1,1) models of nominal exchange rate could explain the crisis that occurred in 1997 and 2008. Based on the predicted value of smoothed probability, it shows that from July 2019 to June 2020, there are no signals of financial crisis in Indonesia.

MEMS gyroscope fault detection and elimination for an underwater robot using the combination of smooth switching and dynamic redundancy method

Micro Electro Mechanical System (MEMS) gyroscope sensors are used in different underwater vehicles to determine their attitude as the input of the controller system to adjust the attitude to the desired value. Fault detection and elimination are necessary for MEMS gyroscope sensors to avoid disruption of the system performance. In this paper, it is tried to study different types of gyroscope sensor faults which can be detected and eliminated by designing a new proposed dynamic redundancy scheme. The proposed method is consisted of two MEMS gyroscope sensors and is modified by considering underwater robot dynamics in threshold tuning via Monte Carlo simulations. The switch between the primary and secondary gyroscope sensors is designed by smoothing methods to eliminate undesirable behavior of switching kick. Finally, numerical and experimental simulations are performed by a three degree of freedom table to show that the proposed method is efficient for the underwater robot exposed to gyroscope sensor faults.