Device Speed Research Articles

A Disturbance Compensation Control Strategy for Rotational Speed Standard Device Based on AMB System.

The rotational speed standard device that can carry loads is the key device for calibrating passive rotational speed sensors. The rotor of the passive rotational speed sensor is connected to the rotor of the standard speed device through a coupling, and the standard reference speed is provided by the standard device. Due to the rotor eccentricity, the unbalanced force of the rotor occurs, and it can not only affect the rotational speed accuracy but can also damage the mechanical bearings of the standard speed device. To solve this issue, a method for suppressing the unbalanced force of the speed standard device based on an active magnetic bearing (AMB) force compensation system is proposed. First, the overall structure of the system is briefly introduced. Then, the force feedback control system model with the AMB as the force actuator is established, and a PI controller is designed to achieve the disturbed force control. Finally, a semi-physical simulation experimental platform is built to verify the effectiveness of the proposed method. The experimental results show that the AMB force compensation system can reduce 84.4%, 81.6%, and 79.8% of the unbalanced vibration force at the frequency of 30 Hz, 90 Hz, and 150 Hz, respectively.

Demonstration of scaling and monolithic stacking for higher integration of integrated circuit using c-axis aligned crystalline oxide semiconductor FET

C-axis-aligned crystalline oxide semiconductor (CAAC-OS) FETs exhibit extremely low off-state leakage current and thus are suitable for low-power devices. Furthermore, CAAC-OS FETs can be integrated in the back end of line process and are promising as memory devices. For higher integration using the CAAC-OS FETs, we examined scaling and monolithic stacking. In addition, we present a 3D dynamic random access memory prototype, which is formed using three-layer monolithically stacked CAAC-OS FETs on a Si-CMOS and exhibits long-term data retention owing to the ultralow off-leakage current. These techniques will contribute to higher speed and integration of memory devices.

Advanced Modeling and Simulation of Multilayer Spin-Transfer Torque Magnetoresistive Random Access Memory with Interface Exchange Coupling.

In advancing the study of magnetization dynamics in STT-MRAM devices, we employ the spin drift-diffusion model to address the back-hopping effect. This issue manifests as unwanted switching either in the composite free layer or in the reference layer in synthetic antiferromagnets-a challenge that becomes more pronounced with device miniaturization. Although this miniaturization aims to enhance memory density, it inadvertently compromises data integrity. Parallel to this examination, our investigation of the interface exchange coupling within multilayer structures unveils critical insights into the efficacy and dependability of spintronic devices. We particularly scrutinize how exchange coupling, mediated by non-magnetic layers, influences the magnetic interplay between adjacent ferromagnetic layers, thereby affecting their magnetic stability and domain wall movements. This investigation is crucial for understanding the switching behavior in multi-layered structures. Our integrated methodology, which uses both charge and spin currents, demonstrates a comprehensive understanding of MRAM dynamics. It emphasizes the strategic optimization of exchange coupling to improve the performance of multi-layered spintronic devices. Such enhancements are anticipated to encourage improvements in data retention and the write/read speeds of memory devices. This research, thus, marks a significant leap forward in the refinement of high-capacity, high-performance memory technologies.

Asynchronous Federated Learning with Grey Wolf Optimization for the Heterogeneity IoT Devices

The Internet of Things (IoT) creates new options for real-time data collection and Machine Learning (ML) model development. Nonetheless, it's feasible that a particular IoT device does not have sufficient computational power to train and implement a complete learning model. However, there are significant communication costs and data security and privacy concerns associated with sending actual data to a centralised server with a lot of computational power. Federated Learning (FL) is a potential way to train ML models using low-powered devices and Edge Servers (ES) since it is a distributed ML architecture. However, the vast majority of the works in existence make the unsustainable assumption of a synchronized parameters update manner with similar IoT nodes and reliable communications networks. To increase training efficiency and accelerate the speed for heterogeneous IoT devices in an unreliable network environment, we designed an Asynchronous Federated Learning strategy with Grey Wolf Optimization (AFL-GWO) in this research. In particular, we develop a Lightweight Node Selection (LNS) technique and propose an AFL-GWO model to efficiently complete learning tasks. To ensure that diverse IoT nodes with varying computational capabilities and network connectivity are represented in the global learning aggregate, the proposed technique makes node selections on an iterative basis. We show through extensive experiments that our suggested AFL-GWO system outperforms the state-of-the-art techniques on identically and independently distributed (IID) and non-IID data distribution in a variety of contexts.

Nanoimprinting Solution-Derived Barium Titanate for Electro-Optic Metasurfaces.

Electro-optic metasurfaces have demonstrated significant potential in enhancing the modulation speed and efficiency for fast and large-scale free-space optical devices. Barium titanate has a strong electro-optic Pockels coefficient, but its availability in thin-film form is restricted due to costly growth processes or low thickness. Here, we fabricated active metasurfaces using an etch-free bottom-up process with sol-gel-based polycrystalline barium titanate with a large electro-optic coefficient similar to bulk lithium niobate. We achieve strong hybrid Mie/surface lattice resonances with a quality-factor of 200 at 633 nm wavelength, enhancing the light-matter interaction and therefore the Pockels effect. The metasurface transmission is electro-optically modulated with up to 5 MHz driving frequency at low voltages of less than 1 V thanks to resonant enhancement of the modulation amplitude by 2 orders of magnitude. This successful demonstration of electro-optic modulation in nanoimprinted barium titanate structures paves the way for low-cost and large-scale free-space modulators or tunable metalenses.

ANALISIS KUALITAS WEBSITE BURSA EFEK INDONESIA DENGAN MENGGUNAKAN METODE GTMETRIX

The Indonesia Stock Exchange is an institution that organizes and provides facilities for securities in Indonesia. This study aims to analyze the quality of how effective and efficient the Indonesia Stock Exchange's website is which can be accessed by all people to get information that is faster and updated for users. Website performance measurement testing is carried out using website performance testing tools with GTMetrix, which can provide website scores and recommendations to improve the performance of the Indonesia Stock Exchange website and speedtest.net is used to measure the internet speed of computer devices by conducting analysis. The results of testing the Indonesia Stock Exchange's website were obtained using GTmetrix to produce an overall score which showed that the Indonesia Stock Exchange's website reached grade A with a green color indicating a percentage of 91%, indicating that the performance of the Indonesia Stock Exchange's website received a very good score. From the results of this performance, it can be concluded that the higher the percentage, the faster the website can be accessed.

A Computational Investigation of the Effects of Temporal Synchronization of Left Ventricular Assist Device Speed Modulation with the Cardiac Cycle on Intraventricular Hemodynamics.

Patients with advanced heart failure are implanted with a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy. Despite advances in pump design, the risk of stroke remains high. LVAD implantation significantly alters intraventricular hemodynamics, where regions of stagnation or elevated shear stresses promote thrombus formation. Third generation pumps incorporate a pulsatility mode that modulates rotational speed of the pump to enhance in-pump washout. We investigated how the timing of the pulsatility mode with the cardiac cycle affects intraventricular hemodynamic factors linked to thrombus formation. Computational fluid dynamics simulations with Lagrangian particle tracking to model platelet behavior in a patient-specific left ventricle captured altered intraventricular hemodynamics due to LVAD implantation. HeartMate 3 incorporates a pulsatility mode that modulates the speed of the pump every two seconds. Four different timings of this pulsatility mode with respect to the cardiac cycle were investigated. A strong jet formed between the mitral valve and inflow cannula. Blood stagnated in the left ventricular outflow tract beneath a closed aortic valve, in the near-wall regions off-axis of the jet, and in a large counterrotating vortex near the anterior wall. Computational results showed good agreement with particle image velocimetry results. Synchronization of the pulsatility mode with peak systole decreased stasis, reflected in the intraventricular washout of virtual contrast and Lagrangian particles over time. Temporal synchronization of HeartMate 3 pulsatility with the cardiac cycle reduces intraventricular stasis and could be beneficial for decreasing thrombogenicity.

Calcined Biowaste Durian Peel as a Heterogeneous Catalyst for Room-Temperature Biodiesel Production Using a Homogenizer Device.

Calcined biowaste durian peel (BDP) contains 86% potassium element as the main compound and has successfully catalyzed the transesterification of palm oil to biodiesel at room temperature. The effect of catalyst weight, molar ratio of palm oil to methanol, reaction time, and rotational speed of the homogenizer device was investigated on biodiesel conversion and yield. The highest biodiesel conversion of 97.4 ± 0.3% was achieved using the following reaction conditions: a catalyst weight of 5 wt %, a molar ratio of palm oil to methanol of 1:15, a reaction time of 10 min, and a rotational speed of 6000 rpm. Unfortunately, calcined BDP could not hold its catalytic activity in the reusability study. The biodiesel conversion was decreased in the second cycle due to the decrease of both catalyst weight and concentration of potassium ions after the first cycle. However, the calcined BDP paired with a homogenizer device could produce biodiesel in a short reaction time and at room temperature.

Nano-structuration influence on the polyimide-based spatial light modulator’s parameters

The classical and the nano-structured spatial light modulators (SLMs) especially based on the polyimide photosensitive layers, as the key element of the optoelectronic devices, display, and telecommunications schemes are considered. The main emphasis is placed on the device with a polyimide photo-layer due to its high sensitivity and acceptable performance. A modulator’s basic characteristics are studied taken into account the comparison with the different types of the photo-layers, such as: ZnSe, ZnS, a-Si:H. Liquid crystal (LC) media is considered as the modulation system. It is indicated that the different methods and approaches are applied for investigation of the basic SLM parameters, such as: Z-scanning technique, third harmonic generation, four-wave mixing set-up, etc. In the current paper the laser holographic technique is used to investigate the resolution, sensitivity, and speed of the LC-SLM devices. The influence of the fullerene doping on the organic photo-layers based on the polyimide materials is presented. This influence of this nano-structuration process on the modulator’s basic parameters is discussed.

Design and Performance Analysis of a Sunflower Cutting Table Based on the Principle of Manual Disk Pick-Up

To solve the problems associated with the poor harvesting ability of existing sunflower harvester cutting tables, and high seed drop rates, we designed a sunflower cutting table that can greatly improve the operational performance of sunflower combine harvesters. In this paper, we introduce the structure and principle of the whole machine and select the key parameters of the cutting table with the goal of adapting to a variety of planting modes in Xinjiang, China. Since the harvesting of sunflower in the wrong row easily causes the sunflower stalks to break, ADAMS (Version: 2020) simulation experiments were carried out to investigate the effects of the forward speed of the machine, the height of the sunflower insertion disk, and the angle of inclination of the harvest divider on the offset angle of the sunflower. With the goal of reducing the offset angle of the stalks in the forward direction of the harvest divider and reducing the size of the cutting table, the harvest divider inclination angle was chosen to be 45°; by using Design-Expert V13.0.15 software, a three-factor, three-level field test was carried out to determine the optimal parameter combinations that resulted in the minimum seed loss rate and the maximum success rate of the disk picking. Moreover, a validation test was conducted. The results show that when the forward speed is set to 0.62 m/s, the lifting speed of the pick-up disk device is set to 0.42 m/s, and the height of the inserted disk is set to 1000 mm, the relative errors between the theoretical values of the disk-picking success rate of the cutting table and the seed loss rate and the field test values are 6.5% and 1.3%, respectively. The results of the present study can provide a reference for improving the performance of sunflower harvester cutting tables and for the mechanical harvesting of inserted disk sunflowers.

Design and Experiment of Oil-Electric Hybrid Air-Suction Sorghum Plot Seeder

To tackle the issues of low seeding accuracy and seed injury caused by the seeders utilized at a small scale and in the plot seeding of sorghum in mountainous or hilly regions, this study presents the design of an oil–electric hybrid air suction sorghum plot seeder. The main working parts of the seeder are described, and the performance of the seed-mixing device is simulated using EDEM software. An oil–electric hybrid drive mode is used to provide power for operation and to the seed-metering device and fan. Additionally, a sowing control and monitoring system is designed using a single-chip microcomputer controller to ensure uniform plant spacing at different forward speeds. A multi-factor experiment is conducted using the central synthesis method to determine the optimal operating parameters of the seed-metering device through bench tests. The results show that a profile hole diameter of 2.5 mm on the seed tray, a negative-pressure chamber vacuum of 8.0 kPa, and a seed-metering device speed of 28 r/min result in a 95.95% pass rate, 0.5% missing rate, and 3.55% reseeding rate. The deviation between the experimental and analytical results that validate the optimum parameters is kept within acceptable limits. Field tests are conducted at different forward speeds using the optimum parameter combinations, and a comparison is made with the widely used duckbill planter. The results show pass, missing, and reseeding rates of 94.41%, 2.3%, and 3.29%, respectively. The missing monitoring error is less than 7.19%. All of the indices of the oil–electric hybrid air suction sorghum plot seeder are superior to those of the duckbill planter; thus, it fulfills the agronomic requirements for seeding a sorghum plot.

Dynamic load modulation predicts right heart tolerance of left ventricular cardiovascular assist in a porcine model of cardiogenic shock.

Ventricular assist devices (VADs) offer mechanical support for patients with cardiogenic shock by unloading the impaired ventricle and increasing cardiac outflow and subsequent tissue perfusion. Their ability to adjust ventricular assistance allows for rapid and safe dynamic changes in cardiac load, which can be used with direct measures of chamber pressures to quantify cardiac pathophysiologic state, predict response to interventions, and unmask vulnerabilities such as limitations of left-sided support efficacy due to intolerance of the right heart. We defined hemodynamic metrics in five pigs with dynamic peripheral transvalvular VAD (pVAD) support to the left ventricle. Metrics were obtained across a spectrum of disease states, including left ventricular ischemia induced by titrated microembolization of a coronary artery and right ventricular strain induced by titrated microembolization of the pulmonary arteries. A sweep of different pVAD speeds confirmed mechanisms of right heart decompensation after left-sided support and revealed intolerance. In contrast to the systemic circulation, pulmonary vascular compliance dominated in the right heart and defined the ability of the right heart to adapt to left-sided pVAD unloading. We developed a clinically accessible metric to measure pulmonary vascular compliance at different pVAD speeds that could predict right heart efficiency and tolerance to left-sided pVAD support. Findings in swine were validated with retrospective hemodynamic data from eight patients on pVAD support. This methodology and metric could be used to track right heart tolerance, predict decompensation before right heart failure, and guide titration of device speed and the need for biventricular support.

Identifying and Understanding the Positive Impact of Defects for Optoelectronic Devices

AbstractDefects are generally regarded to have negative impacts on carrier recombination, charge transport, and ion migration in materials, which thus lower the efficiency, speed, and stability of optoelectronic devices. Meanwhile, lots of efforts which focused on minimizing defects have greatly improved the performances of devices. Then, can defects be positive in optoelectronic devices? Herein, relying on in‐depth understanding of defect‐associated effects in semiconductors, trapping of photo‐generated carriers by defects is applied to enlarge photoconductive gain in photodetection. Therefore, the record photoconductive gain, gain‐bandwidth product, and detection limit are achieved in this photodetector. Exceeding the general concept that defects are harmful, a new view that the defects can be positive in photodetection is identified, which may guide to design high‐performance photodetectors.

Comparison between Power Dissipation and Propagation Delay on 6T SRAM Cell Design Using GDI Logic with Transmission Gate VMSA and Voltage Divider

The rapid evolution of the semiconductor industry has witnessed shrinking portable and mobile devices alongside an increasing demand for extended battery life. Addressing the critical challenges of speed and battery life in digital devices, this paper investigated the effectiveness of innovative low-power design techniques. Focusing on the Gate Diffusion Input (GDI) approach, a recent advancement in the field, a comprehensive analysis revealed its significant potential for reducing power consumption in digital circuits. Additionally, a comparative analysis was conducted to evaluate the performance of conventional 6T GDI SRAM cells and their Modified 6T GDI SRAM with Voltage Divider, considering the influence of Sense Amplifiers. Simulation data demonstrated that Modified 6T SRAM designs, particularly the Voltage Divider and TGVMSA variants, achieved significantly lower power dissipation and delay despite having a larger cell area. Remarkably, the proposed design substantially improved power dissipation and propagation delay, achieving 1.3 ps, and 889.41mV at 1.8V shows that the suggested design enhances power dissipation and propagation delay. These findings suggest that the proposed design offers a promising strategy for enhancing power efficiency and performance in digital devices, thereby mitigating the limitations of battery life and speed in the modern technological landscape.

Design and Experiment of Air-Suction Maize Seed-Metering Device with Auxiliary Guide

Due to the irrational design of the seed discharge plate and the vacuum chamber, the high-speed seed filling effect of the air-suction maize precision seed-metering device is poor. Therefore, an air-suction maize seed-metering device with an auxiliary guide is designed to realize high-speed precision seed discharging. An auxiliary guide filling theory is put forward, and the design of the seed plate type hole charging structure is formulated. Fluent 2022 software is used to analyze nine kinds of vacuum chamber structures; the optimal vacuum chamber structure parameters were determined by polar analysis. In order to investigate the changes of negative pressure and flow speed under the dynamic flow field, a slip grid was used to analyze the dynamic flow field with three different operating speeds and negative pressures. It found that the size of negative pressure did not affect the flow field distribution, and the pressure and flow speed gradually decreased as the distance from the inlet was farther away; meanwhile, the negative pressure distribution and air speed distribution were almost unchanged when the holes at different rotational speeds were at the same position. Finally, bench tests were carried out, and three indexes, namely, the qualified index, the multiple index and the missing index, were selected, with operating speed and negative pressure as factors, two-factor five-level orthogonal test was carried out, and the optimal parameter combinations at 6.0, 7.5, 9.0, 10.5, and 12 km/h forward velocity were derived and verified by regression equations. The results showed that the designed seed-metering device was repeated five times when the pressure of the vacuum chamber was −3.5 kPa and the rotational speed of the seed-metering device was 23 r/min, the average grain spacing qualified index was 95.8%, the missing index was 1.6%, the multiple index was 2.6%, and the indexes met the requirements of precision sowing. It is of great significance for our country’s seeder to develop in the direction of high-speed and precision.

Modeling of non-intrinsic noise in nanometer metal oxide semiconductor field effect transistors

With the proportional reduction of metal–oxide–semiconductor field effect transistor (MOSFET) devices, the short channel effect, the parasitic effect, and the field strength effect are significantly enhanced, the proportion of parasitic resistance increases, and the non-intrinsic noise also increases, which seriously affects the working efficiency of the device. However, existing research mainly focuses on the intrinsic noise of MOSFET, and there is little research on the non-intrinsic noise; furthermore, the models describing the relationship between non-intrinsic noise, device structure, and bias have not yet been addressed. Therefore, in this paper, 90, 65, 32, 10, and 5 nm MOSFETs are studied. The rate of the intrinsic ballistic parameter is introduced to set up the source–drain current model and the non-intrinsic noise model. The source–drain current model is consistent with the theoretical model, numerical simulation, and experimental results in the literature. Finally, the relationship between the non-intrinsic noise and the bias and the device parameters are analyzed, and the conclusion is helpful to improve the working efficiency, lifetime, and response speed of nanoscale MOSFET devices.

Impact of 5G Wireless Technologies on Cloud Computing and Internet of Things (IOT)

With its promise of unmatched speed, low latency, and widespread device connection, the introduction of 5G wireless technology represents a critical turning point in the development of telecommunications. This study examines how 5G would significantly affect cloud computing and the Internet of Things (IoT), two important technical areas.5G brings about a paradigm change in the field of cloud computing by facilitating quicker and more dependable connectivity between end-user devices and cloud servers. High data transmission rates and low latency enable real-time service delivery and processing, creating new opportunities for resource-intensive applications like edge computing, virtual reality, and augmented reality. The integration of 5G with cloud computing has the potential to transform cloud-based services' architecture and functionalities, enhancing their responsiveness and dynamism. Moreover, a new age of automation and communication is heralded by the merging of 5G with IoT. The large flood of IoT devices is accommodated by 5G's expanded network capacity, which facilitates smooth communication and coordination amongst them. By enabling IoT applications with never-before-seen speed and dependability, this synergy opens up new opportunities in industries including industrial automation, smart cities, healthcare, and agriculture. The convergence of 5G and IoT not only expedites the implementation of IoT solutions but also amplifies their efficiency and scalability. But there are obstacles in the way of 5G's revolutionary promise. As more and more devices are connected and data is exchanged, security and privacy issues become critical. In addition, significant financial outlays and careful planning are needed to meet the infrastructure needs for the rollout of 5G. The symbiotic link between 5G, cloud computing, and the Internet of Things is thoroughly examined in this article. It seeks to contribute to the knowledge of the technical environment and direct future research and development activities in order to fully realize the promise of 5G-enabled innovations by analysing the possibilities and difficulties posed by this convergence.

Impact of Interventricular Interaction on Ventricular Function: Insights From Right Ventricular Pressure-Volume Analysis

BackgroundInterventricular interactions may be responsible for the decline in ventricular performance observed in various disease states that primarily affect the contralateral ventricle. ObjectivesThis study sought to quantify the impact of such interactions on right ventricular (RV) size and function using clinically stable individuals with left ventricular assist devices (LVADs) as a model for assessing RV hemodynamics while LV loading conditions were acutely manipulated by changing device speed during hemodynamic optimization studies (ie, ramp tests). MethodsThe investigators recorded RV pressure-volume loops with a conductance catheter at various speeds during ramp tests in 20 clinically stable HeartMate3 recipients. ResultsWith faster LVAD speeds and greater LV unloading, indexed RV end-diastolic volume increased (72.28 ± 15.07 mL at low speed vs 75.95 ± 16.90 at high speed; P = 0.04) whereas indexed end-systolic volumes remained neutral. This resulted in larger RV stroke volumes and shallower end-diastolic pressure-volume relationships. Concurrently, RV end-systolic pressure decreased (31.58 ± 9.75 mL at low speed vs 29.58 ± 9.41 mL at high speed; P = 0.02), but contractility, as measured by end-systolic elastance, did not change significantly. The reduction in RV end-systolic pressure was associated with a reduction in effective arterial elastance from 0.65 ± 0.43 mm Hg/mL at low speed to 0.54 ± 0.33 mm Hg/mL at high speed (P = 0.02). ConclusionsInterventricular interactions resulted in improved RV compliance, diminished afterload, and did not reduce RV contractility. These data challenge the prevailing view that interventricular interactions compromise RV function, which has important implications for the understanding of RV-LV interactions in various disease states, including post-LVAD RV dysfunction.

Low mass-flow operation of small-scale rotating detonation engine

The primary goal of this research was to utilize a range of oxygen/ethylene mixtures in a small-scale Rotating Detonation Engine (RDE) at low mass flow rates to achieve operational detonation frequencies above the 20 kHz threshold of human hearing. A Micro-RDE was designed with an outer diameter of 28 mm and channel gap of 2 mm that yielded detonations at a wide range of testing conditions. Flow was induced via a Jets-in-Crossflow (JIC) scheme to achieve appropriate mixing of reactants before ignition with a pre-detonator device. Two aerospike nozzles of different diameter were tested to change the backpressure on the device and detonation wave speed and frequency were determined using high-speed imagery. Most successful tests yielded two detonation heads. Wave speeds were between 1100 and 1400 m/s and test frequencies were found to be above 31 kHz, well above the audible frequency. A secondary goal of this investigation was to investigate the mixing process within the RDE. Optical access was achieved by implementing a quartz outerbody. Optical imagery of the detonation channel was captured with a Shimadzu camera for detonations ranging from equivalence ratios (Φ) of 0.2–1.7. The fuel and air mixing processes were imaged at MHz rate revealing the local variations in the equivalence ratio that the bulk fluid flow was predominantly axial.

Thermal converter for controlling horizontal wind speed and temperature

This article discusses the design, operation and use of horizontal wind speed and direction control devices. The most commonly used part of the speed converter in the device we analyze is the wind vane converter mounted on the wind vane, which provides an electrical signal of wind direction using a rheostat or electronic transducer. The operating principle of this device is based on the theory of a heat converter, which establishes a relationship between air flow and temperature distribution along the heat conductor of the converter. Purpose : The article is aimed at developing basic concepts and skills about the design, operating principle and methods of using horizontal wind speed and direction control devices. Methods : The operating principle of this device is based on the theory of heat conversion, which establishes the relationship between air flow and temperature distribution along the heat pipe of the converter.