Maximum Operating Research Articles

Sobolev regularity for a class of local fractional new maximal operators

Abstract This paper is devoted to studying the regularity properties for the new maximal operator M φ {M_{\varphi}} and the fractional new maximal operator M φ , β {M_{\varphi,\beta}} in the local case. Some new pointwise gradient estimates of M φ , Ω {M_{\varphi,\Omega}} and M φ , β , Ω {M_{\varphi,\beta,\Omega}} are given. Moreover, the boundedness of M φ , Ω {M_{\varphi,\Omega}} and M φ , β , Ω {M_{\varphi,\beta,\Omega}} on Sobolev space is established. As applications, we also obtain the bounds of the above operators on Sobolev space with zero boundary values.

Fractional Medians and Their Maximal Functions

Fractional Medians and Their Maximal Functions

Body Composition, Vascular Health, Cardiorespiratory Fitness, Lung Function, Muscle Architecture, and Physical Activity in People with Young Onset Dementia: A Case-Control Study

BackgroundBody composition, blood pressure, estimated maximal oxygen uptake (VO2max), lung function, physical activity, muscle architecture, and endothelial function had not previously been examined in people with young onset dementia. Therefore, the study measured these variables in a young onset dementia group, compared them to age-matched controls. MethodsEstimated VO2max (via the Astrand-Rhyming test), body composition, blood pressure, lung function (via spirometry), muscle architecture (via ultrasonography) and endothelial function (via flow mediated dilation) were assessed. Physical activity was measured using ActiGraph accelerometers for 7 days. ResultsWe recruited 33 participants (16 young onset dementia, 17 controls). The young onset dementia group had shorter fascicle lengths of the vastus lateralis, were sedentary for longer over a seven-day period, and completed less moderate-vigorous physical activity than controls (p=0.028, d=0.81; large effect, p=0.029, d=0.54; moderate effect, and p=0.014, d=0.97; large effect, respectively for pairwise comparisons). Pairwise comparisons suggest no differences at the p<0.05 level between young onset dementia and controls for estimated VO2max (despite a moderate effect size [d=0.66]), height, body mass, BMI, blood pressure, light physical activity, lung function, muscle thickness, pennation angle, or endothelial function. ConclusionThis study highlights differences between people with young onset dementia and controls, underscoring the need for multicomponent exercise interventions. Future interventions should target muscle architecture, increase moderate-vigorous physical activity, and reduce sedentariness, with the goal of improving quality of life and promoting functional independence.

Behaviour of liquefaction for Darbandikhan Dam consequence impact of seismic load

Abstract Embankment dams are at risk of damage due to the impact of earthquakes. Rock-filled dam structures are especially vulnerable to earthquakes. To assess the impact of earthquakes, it is important to study liquefaction, which is a significant factor affecting the dynamic behavior of the dams. This study aims to determine the probability that the Darbandikhan rock-fill dam on the (Sirwan- Diyala) river in Iraq may liquefy using two-dimensional numerical modelling and finite element analysis, which is located in Alsulamaniyah north of the capital of Iraq, Baghdad 230 km. The simulation results are compared in terms of different water levels 434, 472, and 485m.a.s.l., different peak accelerations of the earthquakes (0.02, 0.04, 0.06 and 0.08) and different duration of earthquakes 25, 50, 75, and 100sec. As, a result the liquefaction zone increases with increasing upstream water level, acceleration, and duration. So, when the maximum operation water level was 485 m, the percentage of liquefaction area was 20% at peak acceleration of 0.08 g, and a duration of 100s. After that, the liquefaction zone decreases with a decreasing upstream water level of 472 m, for the same acceleration and duration of up to 12.5%. However, this percentage when the minimum water level of 434 m, acceleration 0.08g, and duration 100s, decreases by 65% from the liquefaction zone at elevation 485 m.a.s.l.

Analytical Model of Maximum Operating Frequency of Class-D ZVS Inverter with Linearized Parasitic Capacitance and any Duty Ratio

Analytical Model of Maximum Operating Frequency of Class-D ZVS Inverter with Linearized Parasitic Capacitance and any Duty Ratio

Assembling and testing optoelectronic system to record and process signals from fiber-optic sensors

The given research presents assembling and testing optoelectronic system to record and process signals from fiber-optic sensors. The main optoelectronic systems to record and process the signals from fiber-optic sensors are light source controller and optical power detector. There was assembled controller diagram, which apart from light source includes current source for its adequate operation, as well as the systems necessary for stabilizing its working point. The scheme was modelled for specifying nominal and maximum operation criteria. Construction has been designed in the way, that light source controller includes structures of the current regulation and stabilization super luminescent diode (SLED) and temperature stabilization. Apart from that, there was assembled the microsystem of optical power detector additionally to the light detector, which includes the microsystems of intensification and filtration of the signal measured, processing analog data into digital form, microcontroller, used for preliminary data analysis. Data of optoelectronic systems diagram to record and process the signals from fiber-optic sensors has high response speed, low noise level and sufficient progress.

Second Toe-to-thumb Transfer Using Intramedullary Screw Fixation after Traumatic Thumb Amputation.

Loss of the thumb secondary to trauma leads to significant disability due to the digit contributing 40% of overall hand function. Toe-to-thumb transfer has been a well-studied reconstructive method as a means to restore function after thumb amputation. First described in 1969 by Cobbett and colleagues, toe-to-thumb transfers have undergone several modifications in technique to better improve functional and aesthetic outcomes, including toe wrap-around flaps, trimmed great toe transfer, and second toe transfers. Although these methods have allowed patients to retain use of the thumb, traditional interosseous wire reattachment often leads to significant stiffness and need for prolonged rehabilitation to regain maximal function. Intramedullary screw fixation has been increasingly used in phalanx and metacarpal fractures, but its implementation outside of these contexts is not well reported. Here, we present a case of a patient who presented with traumatic thumb amputation and was treated with second toe-to-thumb transfer with intramedullary screw fixation, a novel mode of interosseous rigid fixation in toe-to-hand surgery. Postoperatively, our patient was able to begin mobilizing the new thumb immediately, which allowed for earlier return to work. We believe our technique can be applied to other cases of second toe, as well as great toe, transfers to improve length of recovery and rehabilitation postoperatively.

Gradient Estimates in the Whole Space for the Double Phase Problems by the Maximal Function Method

Gradient Estimates in the Whole Space for the Double Phase Problems by the Maximal Function Method

A fixed-time stable forward–backward dynamical system for solving generalized monotone inclusions

AbstractWe propose a forward–backward splitting dynamical system for solving inclusion problems of the form $$0\in A(x)+B(x)$$ 0 ∈ A ( x ) + B ( x ) in Hilbert spaces, where A is a maximal operator and B is a single-valued operator. Involved operators are assumed to satisfy a generalized monotonicity condition, which is weaker than the standard monotone assumptions. Under mild conditions on parameters, we establish the fixed-time stability of the proposed dynamical system. In addition, we consider an explicit forward Euler discretization of the dynamical system leading to a new forward backward algorithm for which we present the convergence analysis. Applications to other optimization problems such as constrained optimization problems, mixed variational inequalities, and variational inequalities are presented and some numerical examples are given to illustrate the theoretical results.

Modified Inertial Krasnosel'skii-Mann Type Method for Solving Fixed PointProblems in Real Uniformly Convex Banach Spaces

We present an altered version of the inertial Krasnosel'skii-Mann algorithm and demonstrate convergence outcomes for mappings that are asymptotically nonexpansive within real, uniformly convex Banach spaces. To achieve our results, we skillfully construct the inequality in equation \eqref{6} and apply it accordingly. Our findings support and broadly generalize a number of significant findings from the literature. We demonstrate, as an application, the generation of maximal monotone operators' zeros via fixed point methods in Hilbert spaces. Additionally, we solve convex minimization issues using our fixed-point techniques.

Fractional elliptic obstacle systems with multivalued terms and nonlocal operators

In this paper, we introduce and study a fractional elliptic obstacle system, which is composed of two elliptic inclusions with fractional (pi, qi)-Laplace operators, nonlocal functions, and multivalued terms. The weak solution of fractional elliptic obstacle system is formulated by a fully nonlinear coupled system driven by two nonlinear and nonmonotone variational inequalities with constraints. The nonemptiness and compactness of solution set in the weak sense are proved via employing a surjectivity theorem to the multivalued operators formulated by the sum of a multivalued pseudomonotone operator and a maximal monotone operator.

End-to-End Autonomous Driving Decision Method Based on Improved TD3 Algorithm in Complex Scenarios.

The ability to make informed decisions in complex scenarios is crucial for intelligent automotive systems. Traditional expert rules and other methods often fall short in complex contexts. Recently, reinforcement learning has garnered significant attention due to its superior decision-making capabilities. However, there exists the phenomenon of inaccurate target network estimation, which limits its decision-making ability in complex scenarios. This paper mainly focuses on the study of the underestimation phenomenon, and proposes an end-to-end autonomous driving decision-making method based on an improved TD3 algorithm. This method employs a forward camera to capture data. By introducing a new critic network to form a triple-critic structure and combining it with the target maximization operation, the underestimation problem in the TD3 algorithm is solved. Subsequently, the multi-timestep averaging method is used to address the policy instability caused by the new single critic. In addition, this paper uses Carla platform to construct multi-vehicle unprotected left turn and congested lane-center driving scenarios and verifies the algorithm. The results demonstrate that our method surpasses baseline DDPG and TD3 algorithms in aspects such as convergence speed, estimation accuracy, and policy stability.

Integrating Feature Selection with Machine Learning for Accurate Reservoir Landslide Displacement Prediction

Accurate prediction of reservoir landslide displacements is crucial for early warning and hazard prevention. Current machine learning (ML) paradigms for predicting landslide displacement demonstrate superior performance, while often relying on various feature engineering techniques, such as decomposing into different temporal lags and feature selection. This study investigates the impact of various feature selection techniques on the performance of ML algorithms for landslide displacement prediction. The Shuping and Baishuihe landslides in China’s Three Gorges Reservoir Area are used to comprehensively benchmark four prevalent ML algorithms. Both static ML models, including backpropagation neural network (BPNN), support vector machine (SVM), and dynamic models, such as long short-term memory (LSTM), and gated recurrent unit (GRU), are included. Each ML model is evaluated under three feature engineering techniques: raw multivariate time series, and feature selection under maximal information coefficient-partial autocorrelation function (MIC-PACF), or grey relational analysis-PACF (GRA-PACF). The results demonstrate that appropriate feature selection methods could significantly improve the performance of static ML models. In contrast, dynamic models effectively leverage inherent capabilities in capturing temporal dynamics within raw multivariate time series, seeing marginal gains with extensive feature engineering compared to no feature selection strategy. The optimal feature selection approach varies based on the ML model and specific landslide, highlighting the importance of case-specific assessments. The findings in this study offer guidance on integrating feature selection techniques with different machine learning models to maximize the robustness and generalizability of data-driven landslide displacement prediction frameworks.

Inverse Class‐E power amplifier with broadband capability at different switch‐off duty ratio

AbstractThe paper explores the investigation of an inverse Class‐E amplifier featuring a series output filter across various switch‐off duty ratios D. Analysis of different duty ratios as a design parameter reveals their impact on peak switch voltage, output power capability, and maximum operating frequency. Notably, it is demonstrated that adjusting the D ratio affects these parameters, with specific emphasis on achieving a maximum normalized switch voltage lower than 2 and an output power capability exceeding 0.1 for D = 0.7. Furthermore, the paper considers both parasitic shunt capacitance and series inductor in the load network, a departure from previous works that solely focused on the series inductor. The proposed circuit is highlighted for its ease of implementation compared with conventional reactance compensation circuits employing parallel resonant circuits, which are challenging to form directly. An innovative approach is introduced to showcase the broadband performance of the inverse Class‐E amplifier. The measured drain efficiency and output power versus input power at 430 MHz are 82% and 45.3 dBm, respectively. A similar performance can be achieved within the frequency range of 380–600 MHz by proper tuning at saturated power. The measurement results demonstrate a maximum high power‐added efficiency (PAE) of 79% and drain efficiency of 82% within this frequency range, accompanied by a gain exceeding 12.0 dB and output power surpassing 44 dBm.

Exploring the effects of molecular beam epitaxy growth characteristics on the temperature performance of state-of-the-art terahertz quantum cascade lasers

This study conducts a comparative analysis, using non-equilibrium Green’s functions (NEGF), of two state-of-the-art two-well (TW) Terahertz Quantum Cascade Lasers (THz QCLs) supporting clean 3-level systems. The devices have nearly identical parameters and the NEGF calculations with an abrupt-interface roughness height of 0.12 nm predict a maximum operating temperature (Tmax) of ~ 250 K for both devices. However, experimentally, one device reaches a Tmax of ~ 250 K and the other a Tmax of only ~ 134 K. Both devices were fabricated and measured under identical conditions in the same laboratory, with high quality processes as verified by reference devices. The main difference between the two devices is that they were grown in different MBE reactors. Our NEGF-based analysis considered all parameters related to MBE growth, including the maximum estimated variation in aluminum content, growth rate, doping density, background doping, and abrupt-interface roughness height. From our NEGF calculations it is evident that the sole parameter to which a drastic drop in Tmax could be attributed is the abrupt-interface roughness height. We can also learn from the simulations that both devices exhibit high-quality interfaces, with one having an abrupt-interface roughness height of approximately an atomic layer and the other approximately a monolayer. However, these small differences in interface sharpness are the cause of the large performance discrepancy. This underscores the sensitivity of device performance to interface roughness and emphasizes its strategic role in achieving higher operating temperatures for THz QCLs. We suggest Atom Probe Tomography (APT) as a path to analyze and measure the (graded)-interfaces roughness (IFR) parameters for THz QCLs, and subsequently as a design tool for higher performance THz QCLs, as was done for mid-IR QCLs. Our study not only addresses challenges faced by other groups in reproducing the record Tmax of ~ 250 K and ~ 261 K but also proposes a systematic pathway for further improving the temperature performance of THz QCLs beyond the state-of-the-art.

Indirect drive ICF design study for a 3 MJ NIF enhanced yield capability

A proposed upgrade to the National Ignition Facility is under consideration that would ultimately increase the maximum operating envelope for the laser to 3.0 MJ with a peak power of 450 TW. This upgrade would provide opportunities to address an expanded set of data needs for NNSA’s Stockpile Stewardship mission, including the potential to generate fusion yields ≥30 megajoules. A simplified model of ignition and burn is used to scope the theoretical maximum target yield as a function of laser driver energy. We examine two indirect drive ICF target designs that make use of the 3 MJ laser drive using a common model for integrated laser-hohlraum simulations. These two designs compare and contrast the impacts of two different ablator materials, pure carbon and CH. Additionally, the potential for increased backscatter from these larger scale designs is discussed.

Liquid Cooling of Fuel Cell Powered Aircraft: The Effect of Coolants on Thermal Management

Abstract Electric propulsors powered by Proton Exchange Membrane Fuel Cells (PEMFCs) offer a net zero solution to aircraft propulsion. Heat generated by the PEMFCs can be transferred to atmospheric air via a liquid cooling system; however, the cooling system results in parasitic power and adds mass to the propulsion system, thereby affecting system specific power. The design of the cooling system is sensitive to the choice of liquid coolant and so informed coolant selection is required if associated parasitic power and mass are to be minimized. Two approaches to selection of coolants for PEMFC-powered aircraft are presented in this paper for operating temperatures in the range 80-200°C (this covers low, intermediate, and high temperature PEMFCs). The first approach uses a Figure of Merit (FoM) alongside minimum and maximum operating temperature requirements. The FoM supports the selection of coolants that minimize pumping power and mass while maximizing heat transfer rate. The second approach uses a cooling system model to select ȜPareto efficientȝ coolants. A hybrid-electric aircraft using a PEMFC stack is used as a representative case study for the two approaches. Hydrocarbon-based coolants are shown to be favorable for the case study considered here (aromatics for PEMFCs operating at &amp;lt;130°C and aliphatics for PEMFCs operating at &amp;gt;130°C). As the PEMFC operating temperature increases, the parasitic power and mass of the TMS decreases. Operating at elevated temperatures is therefore beneficial for liquid cooled PEMFC-powered aircraft. Nevertheless, there are diminishing performance gains at higher operating temperatures.

All colloidal supercapattery: colloid@carbon cloth electrodes meet "water‐in‐salt" electrolyte

The pursuit of excellent electrochemical performance, nonflammability and environmental friendliness of aqueous batteries and supercapacitors has driven efforts to find high‐energy yet reliable electrode materials and electrolyte solutions. Here, all colloidal supercapattery are developed using high‐concentration "water‐in‐salt" electrolytes (LiTFSI‐KOH) and pseudocapacitive colloid@carbon cloth as both positive and negative electrodes, which showed merits of batteries and supercapacitors. Ni/Co‐colloid @carbon cloth positive and Fe‐colloid @carbon cloth negative electrodes can be synthesized by in situ electrochemical reaction. The maximum operating voltage of an aqueous colloidal supercapattery is 1.8 V, and the energy density can reach 73.98 Wh kg−1 at a power density of 1799.5 W kg‐1. The specific capacitance of the aqueous colloidal supercapattery still maintains 74.3% of the initial after 2000 cycles of charge/discharge measurement. The combination of quasi ion colloidal materials and "water‐in‐salt" electrolyte pave a profound way to achieve high energy and power ability simultaneously at the supercapattery device.

Criteria of a Two-Weight, Weak-Type Inequality in Orlicz Classes for Maximal Functions Defined on Homogeneous Spaces

In this study, some new necessary and sufficient conditions for a two-weight, weak-type maximal inequality of the form φ1(λ)∫{x∈X:Mf(x)&gt;λ}ϱ(x)dμ(x)≤c∫Xφ2c|f(x)|σ(x)dμ(x) are obtained in Orlicz classes, where Mf is a Hardy–Littlewood maximal function defined on homogeneous spaces and ϱ is a weight function.

Improved endpoint bounds for the lacunary spherical maximal operator

Improved endpoint bounds for the lacunary spherical maximal operator