Speed Reversal Research Articles

A Brief Review on Caenorhabditis elegans Role in Modelling Neurodegenerative Disease.

A small, translucent nematode known as Caenorhabditis elegans, or C. elegans, is frequently utilized as a model organism in biomedical studies. These worms, which are around 1 mm long and feed on bacteria, are usually found in soil. For accessible and effective research on genetics, developmental biology, neuroscience, cell biology, and aging, C. elegans provide an ideal model. Its simplicity, which includes a translucent body and a nervous system with only 302 neurons, makes it possible to see cellular and developmental processes in great detail. Because of its special benefits, the worm Caenorhabditis elegans allows for a thorough characterization of the cellular and molecular processes causing age-related neurodegenerative diseases. This is a general review of the life cycle, experimental methodologies, and the use of C. elegans to model brain diseases, including those related to molecular and genetic factors that cause neurodegenerative diseases. Additionally, we go over how C. elegans is a perfect model organism for studying neurons in instances of prevalent age-related neurodegenerative illnesses due to a combination of its biological traits and new analytical techniques. The literature review process was carried out step-by-step using online search databases such as Web of Science, PubMED, Embase, Google Scholar, Medline, and Google Patents. In the first searches, keywords like C.elegans, disease modelling, and neuroprotective activity were employed. Because of C. elegans's physiological transparency, it is possible to track the development of neurodegeneration in aging organisms by using co-expressed fluorescent proteins. Importantly, a fully characterized connectome provides a unique ability to precisely connect cellular death with behavioural instability or phenotypic diversity in vivo, thus permitting a deep knowledge of the detrimental effect of neurodegeneration on wellbeing. In addition, pharmacological therapies and both forward and reverse gene screening speed up the discovery of modifiers that change neurodegeneration. These chemical-genetic investigations work together to determine important threshold states that either increase or decrease cellular stress in order to unravel related pathways.

Hedging irrigated maize crop yields using temperature derivatives in Malawi

Agriculture production yield varies with weather changes. This causes farmers incur loses. For instance, extreme temperature leads to low maize yield. This study describes incomplete temperature weather derivatives in agriculture markets and applies risk management hedging techniques. It focuses on hedging crop yield against extreme temperatures during irrigation, farming which is done without greenhouse. This study's primary goal is to hedge irrigated maize crop yields using temperature derivatives. This is achieved firstly by modelling a daily average temperature stochastical model. Then, deriving statistical properties of the model based on 1990–2020 Kasungu District Temperature historical data. Lastly, pricing temperature derivatives to hedge maize crop yield. This study uses 1990–2020 Kasungu District Temperature historical data. Then a stochastically Ornstein-Uhlenbeck process with the time-varying speed of reversion, seasonal mean, and local volatility that depends on the local average temperature was proposed. Based on the average temperature model, down and output barrier option pricing models for average temperature and growing degree day (GDD) are applied. The study results shows that when the GDD is above the barrier level the barrier option does not knock out. Hence gives the holder the right to buy the underlying asset since it does not reach or fall below a predefined level over the option's lifetime. If the GDD does not exceed the barrier level, then the farmer will not have to pay the premium because the option is invalid. On the same note, the farmer will have to exercise his right by paying the premium of calculated premium when the GDD exceeds the barrier level. In return for this, the farmer gets paid off which happens to be the difference between GDD and barrier multiplied $1. In line with Malawi's 2063 Millennium Development Goals (MDGs), this study acts as an eye opener for the government to put a policy on whether derivatives should be practised in our country hence, increase cash holding by improving the situation of the farmer and country.

Earnings mean reversion and dynamic optimal capital structure

We formulate a trade-off model that integrates mean reversion in earnings, encompassing dynamic financing decisions that entail both the initial leverage selection and the subsequent decision related to the financing of a growth option. We identify that higher earnings mean reversion speed increases both initial and subsequent leverage ratios for growth option financing and accelerates investment, revealing the volatility-mitigating role of mean reversion speed. Furthermore, our analysis reveals a U-shaped relation between profitability and leverage, influenced by the presence of growth options. In contrast, higher long-term profitability has a positive relationship with leverage, highlighting the differential impact of long-term versus contemporaneous profitability on leverage. The model also yields further implications for corporate policies regarding debt priority structure, investment timing, default thresholds, and credit spreads, contingent on earnings mean reversion dynamics. Our empirical analysis reveals the prevalence of mean reversion in earnings among US firms and provides a comparison of capital structure decisions of firms with mean reverting earnings against firms having non-stationary earnings dynamics.

Numerical investigation of hydraulic instability of pump-turbines in fast pump-to-turbine transition

The fast pump-to-turbine transition of a pumped storage unit is highly responsive to electrical power system regulation demands and is a critical process for the unit itself. The correct prediction of this hydraulic transient process is crucial to avoid issues during machine operation. In this study, a three-dimensional numerical model of the transition process of a pumped storage hydraulic system was proposed and analyzed. Numerical simulations were performed to investigate the variations in external parameters, pressure pulsations, and the evolution of internal flow patterns and vortical structures in the pump turbine. The results showed that the stepwise variations in the flow rate, torque, and force were synchronized with the movement of the guide vanes. Notably, during the pump braking operation and runner speed reversal, a considerable time period with significant force oscillations and intense torque fluctuations occurred, particularly in the vaneless region, where pressure fluctuations were notable. Vortical structures that induce vibrations and intense pressure fluctuations were localized near the runner inlet and at the leading and trailing edges of the guide and stay vanes. This study offers theoretical insights that are crucial for enhancing the stability of the fast pump-to-turbine transitional process, thus optimizing its control strategies.

Sensorless fuzzy-sliding mode control of five phases permanent magnet synchronous motor using MRAS: in three different operating modes

This paper presents a comprehensive study on sensorless control techniques for five-phase permanent magnet synchronous motors (5P-PMSMs). To optimize the speed control performance of (5P-PMSM), which has more advantages than its counterpart three-phase PMSM system, we utilized a combination of fuzzy logic and sliding mode control techniques to optimize the proposed sliding mode control. Additionally, the Model Reference Adaptive System (MRAS) is employed to estimate the speed and rotor position of the 5P-PMSM to enhance the robustness and adaptability of the control system. The modelling of the machine, detailed with a robust nonlinear strategy based on the sliding control, is introduced to track the system until the desired sliding surface is achieved first. To guarantee that the tracking errors converge, the sliding mode control has a chatter due to the discontinuous term. To mitigate the drawback, the proposed control is designed by combining SMC with fuzzy logic, enhancing the performance in a steady state. Examining the control performance of the integrated control fuzzy-SMC with MRAS in different operating modes, including three tests in reversal speed operation, open phase fault mode, and the low-speed operating mode under load torque. The main aim is to assess and analyze the robustness and performance of the proposed control strategy. The stability of the overall control system is examined using the Lyapunov theorem and Popov’s theory analysis of MRAS observer stability. The simulation results of the suggested control displayed by MATLAB-Simulink illustrate the effectiveness and adaptability of the sensorless control scheme across different operating conditions, offering promising prospects for practical implementation in industrial applications.

The fundamental solution of the master equation for a jump‐diffusion Ornstein–Uhlenbeck process

AbstractAn integro‐differential equation for the probability density of the generalized stochastic Ornstein–Uhlenbeck process with jump diffusion is considered for a special case of the Laplacian distribution of jumps. It is shown that for a certain ratio between the intensity of jumps and the speed of reversion, the fundamental solution can be found explicitly, as a finite sum. Alternatively, the fundamental solution can be represented as converging power series. The properties of this solution are investigated. The fundamental solution makes it possible to obtain explicit formulas for the density at each instant of time, which is important, for example, for testing numerical methods.

Translation velocity determines the efficacy of engineered suppressor tRNAs on pathogenic nonsense mutations

Nonsense mutations – the underlying cause of approximately 11% of all genetic diseases – prematurely terminate protein synthesis by mutating a sense codon to a premature stop or termination codon (PTC). An emerging therapeutic strategy to suppress nonsense defects is to engineer sense-codon decoding tRNAs to readthrough and restore translation at PTCs. However, the readthrough efficiency of the engineered suppressor tRNAs (sup-tRNAs) largely varies in a tissue- and sequence context-dependent manner and has not yet yielded optimal clinical efficacy for many nonsense mutations. Here, we systematically analyze the suppression efficacy at various pathogenic nonsense mutations. We discover that the translation velocity of the sequence upstream of PTCs modulates the sup-tRNA readthrough efficacy. The PTCs most refractory to suppression are embedded in a sequence context translated with an abrupt reversal of the translation speed leading to ribosomal collisions. Moreover, modeling translation velocity using Ribo-seq data can accurately predict the suppression efficacy at PTCs. These results reveal previously unknown molecular signatures contributing to genotype-phenotype relationships and treatment-response heterogeneity, and provide the framework for the development of personalized tRNA-based gene therapies.

Sustainable power management in light electric vehicles with hybrid energy storage and machine learning control

This paper presents a cutting-edge Sustainable Power Management System for Light Electric Vehicles (LEVs) using a Hybrid Energy Storage Solution (HESS) integrated with Machine Learning (ML)-enhanced control. The system's central feature is its ability to harness renewable energy sources, such as Photovoltaic (PV) panels and supercapacitors, which overcome traditional battery-dependent constraints. The proposed control algorithm orchestrates power sharing among the battery, supercapacitor, and PV sources, optimizing the utilization of available renewable energy and ensuring stringent voltage regulation of the DC bus. Notably, the ML-based control ensures precise torque and speed regulation, resulting in significantly reduced torque ripple and transient response times. In practical terms, the system maintains the DC bus voltage within a mere 2.7% deviation from the nominal value under various operating conditions, a substantial improvement over existing systems. Furthermore, the supercapacitor excels at managing rapid variations in load power, while the battery adjusts smoothly to meet the demands. Simulation results confirm the system's robust performance. The HESS effectively maintains voltage stability, even under the most challenging conditions. Additionally, its torque response is exceptionally robust, with negligible steady-state torque ripple and fast transient response times. The system also handles speed reversal commands efficiently, a vital feature for real-world applications. By showcasing these capabilities, the paper lays the groundwork for a more sustainable and efficient future for LEVs, suggesting pathways for scalable and advanced electric mobility solutions.

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO2/ZrO2ferroelectric capacitors towards long endurance and high temperature retention.

A novel defect control approach based on laminated HfO2/ZrO2with multifunctional TiN/Mo/TiOxNyelectrode is proposed to significantly improve the endurance and data retention in HZO-based ferroelectric capacitor. The O-rich interface reduces leakage current and prolong the endurance up to 1011cycles while retaining a 2Pr value of 34 (μC cm-2) at 3.4 MV cm-1. Using first-principles calculations and experiments, we demonstrate that the enhancement of endurance is ascribed to the higher migration barrier of oxygen vacancies within the laminated HZO film and higher work function of MoOx/TiOxNybetween top electrode and the insulating oxide. This 2.5 nm thick TiOxNybarrier further increase the grain size of HZO, lowering the activation field and thus improving polarization reversal speed. This interfacial layer further decreases the overall capacitance, increases the depolarization field, thereby enhancing the data retention. By fitting the data using the Arrhenius equation, we demonstrate a 10 years data retention is achieved at 109.6 °C, surpassing traditional SS-HZO of 78.2 °C with a 450 °C rapid thermal annealing (required by backend-of-the-line). This work elucidates that interfacial engineering serves as a crucial technology capable of resolving the endurance, storage capability, and high-temperature data retention issues for ferroelectric memory.

Enhanced Volts-per-Hertz Sensorless Starting of Permanent Magnet Motor with Heavy Loads in Long-Cable Subsea Applications

Permanent magnet (PM) motors are gaining prominence in subsea applications such as drilling, pumping, and boosting for oil and natural gas extraction. These motors are gradually replacing traditional induction motors. However, starting and operating PM motors at low speeds under heavy loads poses significant challenges. This is because of unknown initial rotor positions and resistive voltage drops due to the presence of a sinewave filter, transformer, and long cable. An unknown rotor position may result in temporary reverse speed, which may cause a loss of synchronism; therefore, initial rotor position estimation is preferable. Additionally, addressing the voltage drop issue requires careful voltage compensation to avoid transformer core saturation. In this paper, an enhanced V/Hz starting of a PM motor is proposed with initial position detection (IPD) and voltage compensation to start the motor reliably with a heavy load. The proposed control method is verified with controller hardware in the loop (C-HIL) real-time simulation using a Typhoon HIL-604 emulator and a Texas Instruments TMS320F28335 digital signal processor (DSP) control card.

Impacts of anemometer changes, site relocations and processing methods on wind speed trends in China

Abstract. In situ surface wind observation is a critical meteorological data source for various research fields. However, data quality is affected by factors such as surface friction changes, station relocations and anemometer updates. Previous methods to address discontinuities have been insufficient, and processing methods have not always adhered to World Meteorological Organization (WMO) World Climate Programme guidelines. We analyzed data discontinuity caused by anemometer changes and station relocations in China's daily in situ near-surface (∼ 10 m) wind speed observations and the impact of the processing methods on wind speed trends. By comparing the wind speed discontinuities with the recorded location changes, we identified 90 stations that showed abnormally increasing wind speeds due to relocation. After removing those stations, we followed a standard quality control method recommended by the World Meteorological Organization to improve the data reliability and applied Thiessen polygons to calculate the area-weighted average wind speed. The result shows that China's recent reversal of wind speed was reduced by 41 % after removing the problematic stations, with an increasing trend of 0.017 m s−1 yr−1 (R2 = 0.64, P < 0.05), emphasizing the importance of robust quality control and homogenization protocols in wind trend assessments.

Contribution of the Magnetic Subsystem to the Generation of Longitudinal Acoustic Waves during Domain Wall Motion in Yttrium Orthoferrite

Purpose. Modern technologies in their development are increasingly in need of increasing the speed of processing and recording information. An alternative to semiconductor methods is magnetic memory based on changing magnetic moments. The speed of magnetization reversal is determined by the speed of motion of domain walls. The speed is maximum in weak ferromagnets. The purpose of this work is to study the effect of a magnetic wave generated by a moving domain wall on a longitudinal acoustic wave, taking into account the absorption of a magnetic wave in yttrium orthoferrite.Methods. The equation describing the effect of a magnetic wave generated by a moving domain wall on a longitudinal acoustic wave is solved using the following methods: the slowly varying amplitude method, the perturbation theory method, and the Lagrange method.Results. For an orthoferrite crystal, the contribution of the magnetic wave accompanying the motion of the domain wall in yttrium orthoferrite to the deformation of the amplitude of the longitudinal acoustic wave is calculated. This contribution in a bounded crystal, without taking into account the absorption of magnetic waves in the absence of the influence of acoustic waves on them, is of the order of 10-6 cm. In an unbounded crystal, the corresponding contribution, taking into account the absorption of magnetic waves, into the generation of longitudinal acoustic waves is of the order of magnitude 10-10 cm with a theoretical thickness of the domain wall D3 ≈ 10-6 cm.Conclusion. To study the mechanisms of the influence of a magnetic wave generated by a moving DW on a longitudinal acoustic wave, yttrium orthoferrite was taken. Since a weak ferromagnet is characterized by a significant increase in the magnetoelastic coupling when it overcomes the sound barrier. It is this circumstance that made it possible to experimentally observe the generation of elastic displacements by a moving domain wall. To develop devices for recording and processing information based on weak ferromagnets, it is necessary to fully investigate the mechanisms that affect the dynamics of a domain wall during its motion. Such a factor is the interaction of magnetic and acoustic waves with the domain wall, which can affect the quality of information processing. The evaluation of the contributions of these mechanisms can be used to develop the element base of devices for recording and processing information based on the magnetic memory of weak ferromagnets.

The Effect of the two Handed Reverse HIT Training Model on Reverse HIT Speed and Accuracy in Hockey

The aim of this research is to determine the training model for the two-one-hand reverse hit technique and the speed and accuracy of reverse hits in the game of hockey. Experimental research method with pre-test and post-test testing on one sample group. The samples in the research were athletes who were members of the Hockey Student Activity Unit and students who took hockey courses at Surabaya State University. Data collection techniques include testing punch speed and punch accuracy. The data analysis technique uses t-test statistical testing of test results before and after being given the training model. The research results show that the Sig. (2-tailed) speed is 0.001 < 0.05, so it is stated that there is a significant difference in the speed of the two-handed backhand in the pre-test and post-test. The sig value. (2-tailed) speed is 0.000 < 0.05, so it is stated that there is a significant difference in the two-handed reverse punch in the pre-test and post-test.

Comparative Investigation of DSP-Based Speed Control of PMSM Using Proportional Integral and Takagi-Sugeno Fuzzy Logic Controller

This paper presents the simulation and experimental results of speed control of a three-phase Permanent Magnet Synchronous Motor (PMSM). The control techniques employed in this work include a Proportional Integral (PI) controller and a Takagi-Sugeno Fuzzy Logic Controller (TS-FLC). While theory and simulation help in predicting the PI controller settings for real drive implementation, further adjustment of the PI controller coefficients is still needed for optimal performance. However, the complexity of PI controller tuning can be overcome by employing a fuzzy logic controller, which is less affected by variations in model parameters and load torque. Two variants of the proposed TS-FLC are implemented: a simple algorithm with 9 rules and a standard algorithm with 49 rules. The drive system utilizes Field Oriented Control (FOC). The control program is developed using the C/C++ programming language and executed on the Texas Instruments TMS320LF28335 Digital Signal Processor (DSP), known for its intelligent motor control capabilities. The drive system evaluation was performed through simulations and experimentation using the MCK28335 professional development kit provided by Technosoft Company. The simulation and experimental results of the proposed controllers are compared under various conditions, including speed reversal and load torque variations.

Numerical Simulation of Stacked Step Flowincentrifugal Force Field for Copper Ore Separation

In this study, the flow field of a stacked step flow device was simulated using Fluent 19.2 software. The simulation results show that: the combination of rotational motion and reverse fluidization of the fluid in the cone of the equipment makes the slurry dispersed and separated in the radial direction, and the upward motion of the fluid can promote the solid phase, especially the smaller particle size and lower density of the silica phase, to realize the separation of the copper phase and the silica phase in the axial direction; the vortex generated by the sudden change of tangential flow velocity at the step can significantly improve the settling efficiency of the copper phase in the upward process. Fluent simulation results show that: when the rotational speed is 50r/min, the feed speed is 0.5m/s, and the reverse fluidization speed is 0.018m/s, the copper recovery rate is 87.70%, and the enrichment ratio is 13.45.

Numerical simulation into influence of airflow channel quantities on melt-blowing airflow field in processing of polymer fiber

Abstract To obtain better airflow field characteristics of melt-blowing and acquire slender melt-blowing fiber, a new die with multi-channel of melt-blowing airflow was designed. The airflow field under the spinneret hole of the melt-blowing die was simulated and analyzed using computational fluid dynamics method, and distribution rules of the ordinary die and the new die on the airflow field along the spinning centerline were compared and discussed. The melt-blowing fiber diameter distribution for the ordinary die and the new die was numerically calculated using a stretching model of the melt-blowing fiber. In contrast with an ordinary die, the new melt-blowing die enhances the average speed in main stretching zone by 89.8% and increases the peak speed by 50.4%. The higher airflow temperature of new die improves the softening degree and melting fluidity of the polymer. Meanwhile, the smaller turbulence intensity and the reverse speed of the new die make airflow more stable and reduce disturbance and adhesion of the fiber, and a larger pressure difference and a peak pressure can accelerate the refinement and attenuation of the fiber. The new melt-blowing die with airflow multi-channel is conducive to extension, which is a better choice in the manufacturing process of nonwoven melt-blowing fibers.

Research on variable stiffness asymmetrical resonant linear piezoelectric actuator based on multi-modal drive

In this paper, a linear piezoelectric motor with variable stiffness and asymmetric resonance is proposed, which is driven by a single harmonic signal. Working in the resonant state improve the output performance of the motor. Motor control is relatively simple and can realize reverse movement under the driving of second-order single harmonic signal. At the same time, the new motor can obtain different operating speed and step distance by changing the clamping position in front and back to meet the requirements of different loads and different working conditions and has strong applicability. By experiment, the first-order optimal operating frequency of the motor prototype at three different stiffness adjustment positions is 88 Hz, 90 Hz and 92 Hz respectively. Under the excitation of 240 Vp–p first-order resonance signal, the corresponding output speed of the motor prototype is 16.116 mm s−1, 20.457 mm s−1 and 25.015 mm s−1 respectively, and the corresponding displacement resolution is 0.18 mm, 0.22 mm and 0.27 mm respectively. When the stiffness adjustment positions is 2 mm, the maximum load of the motor prototype reaches 450 g. The second-order optimal operating frequency at the stiffness adjustment positions 1 mm is 601 Hz. Under the excitation of a 240 Vp–p second-order resonant signal, the reverse output speed of the motor prototype is 13.126 mm s−1, and the corresponding displacement resolution is 0.02 mm.

Dual-Stimulus-Driven Dynamically Controllable [3]Rotaxane with Tunable Organic Room-Temperature Phosphorescence.

A dual-stimulus-driven stiff-stilbene-based dynamic [3]rotaxane has been facilely developed using the threading-stoppering strategy and exhibits reversible shuttling motions and bidirectional rotations upon encountering acid-base and distinct light stimulations, respectively. Herein, the two dibenzo-24-crown-8 macrocycles can undergo reversible switching motion between two different stations along the axle suffered from acid-base stimulation, and simultaneously, the two rotaxanes can also perform cis-trans rotations upon irradiation with distinct light. In other words, the constructed rotaxanes can conduct two modes of regular motions without interference. Interestingly, reciprocating switching motion of the rings along the axle enabled the rotaxanes to exhibit controllable and reversible photoisomerization speed, conversion yield, and quantum yield. Crucially, these rotaxanes also manifest adjustable solid-state organic room-temperature phosphorescence (RTP) and photoluminescence stimulated by dual factors (acid-base and diverse light), which are further applied in information encryption and anticounterfeiting. The presented study provides an instructive way for precisely boosting photoisomerization performances and the fabrication of dual-stimuli-induced molecular machines with functions of two-mode mechanical motions and controllable pure organic RTP switches.

Dynamical analysis of a stochastic epidemic HBV model with log-normal Ornstein–Uhlenbeck process and vertical transmission term

Considering the transmission rate perturbed by log-normal Ornstein–Uhlenbeck process, we develop a stochastic HBV model with vertical transmission term. For higher-dimensional deterministic system, the local asymptotic stability of the endemic equilibrium is given by proving the global stability of the corresponding linearized system. For stochastic system, the existence of stationary distribution is obtained by constructing several suitable Lyapunov functions and using the ergodicity of the Ornstein–Uhlenbeck process and the critical value corresponding to the basic reproduction number for determined system is derived, which means the persistence of the disease. And sufficient conditions for disease extinction are given. Furthermore, by solving five-dimensional Fokker–Planck equation, the exact expression of the probability density function near the quasi-equilibrium is provided to reveal the statistical properties. In the end, numerical simulations illustrate our theoretical results and exhibit the trends of the critical values for persistence and extinction of diseases along with the change of noise intensity and reversion speed.

Feedback Linearization Direct Torque Control With Zero-Sequence Current Regulation for DC-Biased VRM Drives

A feedback linearization direct torque control (FL-DTC) scheme with the ability of regulating zero-sequence current is proposed for the DC-biased vernier reluctance machines (DC-VRMs) to improve the steady and dynamic performance of drive system. First, an accurate original nonlinear model of DC-VRM is analyzed in synchronous rotating reference frame with three variables (i.e., the electromagnetic torque, the stator flux, and zero-sequence current). The saturation of self-inductance is considered to ensure the accuracy of model under different load. The virtual 0-axis flux <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ψ₀</i> is firstly defined in this paper. Then, a FL-DTC scheme with zero-sequence current regulation is proposed to improve torque and flux ripple and dynamic response performance. The system stability is verified by the Lyapunov theory. Finally, comparative experiments to conventional PI-based SVM-DTC scheme in steady state and dynamic process are carried out. The advantages of the proposed method are verified, including high control accuracy of torque and flux, fast dynamic response to load change and speed reversal, outstanding low-speed range performance and strong robustness to parameter uncertainties.