Residual Method Research Articles

Eggs, Dietary Choline, and Nonalcoholic Fatty Liver Disease in the Framingham Heart Study

BackgroundEggs are rich in bioactive compounds, including choline and carotenoids that may benefit cardiometabolic outcomes. However, little is known about their relationship with nonalcoholic fatty liver disease (NAFLD). ObjectivesWe investigated the association between intakes of eggs and selected egg-rich nutrients (choline, lutein, and zeaxanthin) and NAFLD risk and changes in liver fat over ∼6 y of follow-up in the Framingham Offspring and Third Generation cohorts. MethodsOn 2 separate occasions (2002–2005 and 2008–2011), liver fat was assessed using a computed tomography scan to estimate the average liver fat attenuation relative to a control phantom to create the liver phantom ratio (LPR). In 2008–2011, cases of incident NAFLD were identified as an LPR ≤0.33 in the absence of heavy alcohol use, after excluding prevalent NAFLD (LPR ≤0.33) in 2002–2005. Food frequency questionnaires were used to estimate egg intakes (classified as <1, 1, and ≥2 per week), dietary choline (adjusted for body weight using the residual method), and the combined intakes of lutein and zeaxanthin. Multivariable modified Poisson regression and general linear models were used to compute incident risk ratios (RR) of NAFLD and adjusted mean annualized liver fat change. ResultsNAFLD cumulative incidence was 19% among a total of 1414 participants. We observed no associations between egg intake or the combined intakes of lutein and zeaxanthin with an incident NAFLD risk or liver fat change. Other diet and cardiometabolic risk factors did not modify the association between egg intake and NAFLD risk. However, dietary choline intakes were inversely associated with NAFLD risk (RR for tertile 3 compared with tertile 1: 0.69, 95% CI: 0.51, 0.94). ConclusionsAlthough egg intake was not directly associated with NAFLD risk, eggs are a major source of dietary choline, which was strongly inversely associated with NAFLD risk in this community-based cohort.

A Remaining Useful Life Prediction of Turbofan Engines Based on Multi-Scale Temporal Convolutional Networks with Dual Squeeze-Excitation Attention Mechanism

Abstract To better handle temporal data and delve into learning the features of the data, a turbofan engine residual life prediction method is proposed, which integrates a dual-squeeze-excitation attention mechanism with a multi-scale temporal convolutional network. Firstly, utilizing a sliding window, the extracted multi-dimensional sensor features undergo overlapping sampling to enhance the model’s perception of temporal data. Secondly, a hybrid network prediction model based on DSE-MTCN is constructed, employing multi-scale convolutional kernels to expand the receptive field of convolution, assigning different weights to features, and adaptively allocating weights to hidden layer units. Lastly, the DSE-MTCN prediction model is globally optimized using the RAdam algorithm. The results demonstrate that this method effectively enhances the accuracy and generalization ability of the prediction model.

Experimental Study on the Thermal Behavior Characteristics of the Oxidative Spontaneous Combustion Process of Fischer–Tropsch Wax Residue

Coal-to-liquid technology is a key technology to ensuring national energy security, with the Fischer–Tropsch synthesis process at its core. However, in actual production, Fischer–Tropsch wax residue exhibits the characteristics of spontaneous combustion due to heat accumulation, posing a fire hazard when exposed to air for extended periods. This significantly threatens the safe production operations of coal-to-liquid chemical enterprises. This study primarily focuses on the experimental investigation of the oxidative spontaneous combustion process of three typical types of wax residues produced during Fischer–Tropsch synthesis. Differential Scanning Calorimetry (DSC) was used to test the thermal flow curves of the three wax residue samples. Kinetic analysis was performed using the Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) methods to calculate their apparent activation energy. This study analyzed the thermal behavior characteristics, exothermic properties, and kinetic parameters of three typical wax residue samples, exploring the ease of reaction between wax residues and oxygen and their tendency for spontaneous combustion. The results indicate that Wax Residue 1 is rich in low-carbon chain alkanes and olefins, Wax Residue 2 contains relatively fewer low-carbon chain alkanes and olefins, while Wax Residue 3 primarily consists of high-carbon chain alkanes and olefins. This leads to different thermal behavior characteristics among the three typical wax residue samples, with Wax Residue 1 having the lowest heat release and average apparent activation energy and Wax Residue 3 having the highest heat release and average apparent activation energy. These findings suggest that Wax Residue 1 has a higher tendency for spontaneous combustion. This research provides a scientific basis for the safety management of the coal chemical industry, and further exploration into the storage and handling methods of wax residues could reduce fire risks in the future.

Spirodiclofen toxicity in Tetranychus urticae and safety to natural enemies Proprioseiopsis asetus and Amblyseius swirskii

Proprioseiopsis asetus and Amblyseius swirskii are excellent natural enemies of plant-feeding mites and small pests. In order to clarify the safety of the acaricide spirodiclofen to the predatory mites P. asetus and A. swirskii, here, we investigated the toxicity of the acaricide on the pest mite T. urticae (nymphs and adult females) and on both species of predatory mites, P. asetus and A. swiskii (eggs, nymphs, and female adults) by using the spray, slide-dip, and leaf residual toxicity methods, compared the selective toxicity and assessed the safety to these natural enemies. The results demonstrated that the corrected mortality in P. asetus and A. swirskii female adults was &lt;5% at recommended spirodiclofen concentrations in the spray method. In the leaf residual toxicity method, P. asetus and A. swirskii egg-hatching rates did not differ significantly from the pure water control group. In the slide-dip method, spirodiclofen lethal concentration 50 (LC50) in P. asetus and A. swirskii female adults was noted to be 9,494.875 and 3,064.187 mg·L−1, respectively. In the spray method, spirodiclofen LC50 in P. asetus and A. swirskii nymphs was found to be 4,292.664 and 1,081.609 mg·L−1, respectively, and that in T. urticae female adults and nymphs was 55.189 and 40.862 mg·L−1, respectively. Spiroclofen selective toxicity ratios (STRs) in P. asetus female adults–T. urticae and P. asetus nymphs–T. urticae were 172.013 and 105.053, respectively, indicating that spiroclofen has a high positive selectivity toward the pest T. urticae and its natural enemy P. asetus. In contrast, spiroclofen STRs in A. swirskiis female adults–T. urticae and A. swirskiis nymphs–T. urticae were 55.522 and 26.470, respectively, indicating spiroclofen has a moderate positive selectivity toward the pest T. urticae and its natural enemy A. swirskii. In the safety evaluation, the spirodiclofen safety factor for P. asetus female adults and nymphs was 158.248–237.37 and 71.544–107.317, respectively, whereas that for A. swirskii female adults and nymphs was 50.070–76.605 and 18.027–27.040 respectively. All spirodiclofen safety factor values were much higher than 5, indicating that spirodiclofen is highly safe for P. asetus and A. swirskii; in particular, spirodiclofen is safer for P. asetus than for A. swirskii.

Free Vibration of Graphene Nanoplatelet-Reinforced Porous Double-Curved Shells of Revolution with a General Radius of Curvature Based on a Semi-Analytical Method

Based on domain decomposition, a semi-analytical method (SAM) is applied to analyze the free vibration of double-curved shells of revolution with a general curvature radius made from graphene nanoplatelet (GPL)-reinforced porous composites. The mechanical properties of the GPL-reinforced composition are assessed with the Halpin–Tsai model. The double-curvature shell of revolution is broken down into segments along its axis in accordance with first-order shear deformation theory (FSDT) and the multi-segment partitioning technique, to derive the shell’s functional energy. At the same time, interfacial potential is used to ensure the continuity of the contact surface between neighboring segments. By applying the least-squares weighted residual method (LWRM) and modified variational principle (MVP) to relax and achieve interface compatibility conditions, a theoretical framework for analyzing vibrations is developed. The displacements and rotations are described through Fourier series and Chebyshev polynomials, accordingly, converting a two-dimensional issue into a suite of decoupled one-dimensional problems. The obtained solutions are contrasted with those achieved using the finite element method (FEM) and other existing results, and the current formulation’s validity and precision are confirmed. Example cases are presented to demonstrate the free vibration of GPL-reinforced porous composite double-curved paraboloidal, elliptical, and hyperbolical shells of revolution. The findings demonstrate that the natural frequency of the shell is related to pore coefficients, porosity, the mass fraction of the GPLs, and the distribution patterns of the GPLs.

Efficient nonlinear model predictive and active disturbance rejection control for trajectory tracking of unmanned vehicles

This article proposes an efficient trajectory tracking control strategy of unmanned vehicles. The method is based on nonlinear model predictive control (NMPC) and active disturbance reject control (ADRC). The designed control algorithm considers three challenges including nonlinear characteristics, multiple constraints, and external disturbance. First, NMPC method is presented for the nonlinear vehicle model with multiple constraints. To relax inequality constraints and reduce the heavy calculation burden, the penalty term with the variable factor is added to the cost function, an improved continuous/generalized minimum residual method is proposed to solve NMPC online optimization problem. Then, an ADRC scheme is designed to estimate the unknown disturbance via extended state observer, and compensate them by feedback control law in real time, the corresponding parameters are obtained by a novel particle swarm optimization algorithm to further improve the control precision. It ensures the stability to a certain extent. Finally, the results indicate the designed algorithm can raise the calculation efficiency and meet the real-time requirements, and obviously increase the tracking accuracy and robustness performance.

Investigation of an Exact Solution of a Mixed Boundary Value Problem Using the Residue Method

Investigation of an Exact Solution of a Mixed Boundary Value Problem Using the Residue Method

Analyzing solution of the fractional Lorenz system and fractional Riccati equation via the modified Laplace power series residual method

Analyzing solution of the fractional Lorenz system and fractional Riccati equation via the modified Laplace power series residual method

A meshfree formulation for size-dependent thermal buckling and post-buckling behaviour of porous microplates on elastic foundation subjected to localized heating

The semi-analytical framework is developed for in-plane thermal stresses within the microplates under localized heating. Localized heating is modelled using Fourier Series expansions over the complete domain of the plate. These stresses within the plate are estimated after solving the in-plane thermoelasticity problem using Airy's stress approach. Utilizing these stresses, present work also studies the buckling and post-buckling behaviour of a porous metal foam microplate resting on Winkler and Pasternak elastic foundations. The plate is modelled using Reddy's third-order shear deformation theory (TSDT) and von Kármán geometric nonlinearity, and the size-dependent effects are included using the modified strain gradient theory (MSGT). Galerkin's weighted residual method converts the partial differential equations (PDEs) into algebraic equations. The post-buckling equilibrium path is obtained using the modified Newton-Raphson method. The mode shapes of the microplate for the various configurations of the plate with different boundary conditions due to localized thermal loading are plotted. Also, these mode shapes are compared with the mode shapes of the microplate due to in-plane mechanical loading. The parametric effect of porosity, elastic foundation parameters, thickness of plate, size of plate, boundary conditions and loading concentrations on the buckling and post-buckling behaviour of the plate is studied.

Statistical and numerical analysis of magnetic field effects on laminar natural convection heat transfer of nanofluid in a hexagonal cavity

This paper presents a statistical and numerical investigation that examines the optimization and sensitivity analysis of the unsteady laminar natural convective heat transfer flow of Fe3O4-water nanofluid in a hexagonal cavity considering the impacts of a sloping magnetic field in one-component nanofluid model. The inclined walls of the cavity are maintained at a constantly low temperature, while the bottom wall is uniformly heated. The upper wall, however, is regarded as adiabatic. The nanofluid thermal conductivity model incorporates the impact of Brownian motion. The Galerkin weighted residual finite element method has been employed to solve the governing dimensionless equations. The results are provided regarding the average Nu, streamlines, and isotherms. The study uses response surface methodology to analyze the sensitivity of parameters such as the Ha, Ra, and nanoparticle volume percentage. Using a response surface policy allows for optimizing the process and identifying the most favorable circumstances to achieve the maximum thermal transfer rate. The flow pattern of the nanofluid is significantly affected by the magnetic field and its alignment. The numerical results indicate a significant rise in the average Nu as the nanoparticle volume percentage, magnetic field inclination angle, nanoparticle type factor, and Ra increase. Conversely, the Hartmann number and the nanoparticle's diameter have contrasting effects. When considering Brownian motion, the average Nu grows by 225.89 % for Ra = 106 with ϕ = 0.03 and 25.28 % for the other case. The optimal condition for heat transfer occurs when Ra = 106, Ha = 4, and ϕ =0.03 while keeping the other parameters constant.

Global quaternion generalized minimal residual method for generalized coupled Sylvester quaternion matrix equations with application to colour image encryption and decryption

ABSTRACT Sylvester matrix equations play important roles in control and system theory. We consider a class of the generalized coupled Sylvester quaternion matrix equations, which includes a lot of special matrix equations such as Stein matrix equation, Lyapunov matrix equation and Sylvester matrix equation on the quaternion skew field. First, the quaternion Krylov subspace and its F-orthogonal basis are constructed via a new quaternion matrix product and the global quaternion Arnoldi process. Then a global quaternion generalized minimal residual (Gl-QGMRES) method is proposed for solving the generalized coupled Sylvester quaternion matrix equations. The convergence of the proposed method is theoretically analysed. Finally, the effectiveness and feasibility of the proposal are verified by some numerical experiments. As an application of Gl-QGMRES method, we establish a kind of colour image encryption and decryption by embedding watermark images.

A Neural Network-Based Poisson Solver for Fluid Simulation

The pressure Poisson equation is usually the most time-consuming problem in fluid simulation. To accelerate its solving process, we propose a deep neural network-based numerical method, termed Deep Residual Iteration Method (DRIM), in this paper. Firstly, the global equation is decomposed into multiple independent tridiagonal sub-equations, and DRIM is capable of solving all the sub-equations simultaneously. Moreover, we employed Residual Network and a correction iteration method to improve the precision of the solution achieved by the neural network in DRIM. The numerical results, including the Poiseuille flow, the backwards-facing step flow, and driven cavity flow, have proven that the numerical precision of DRIM is comparable to that of classic solvers. In these numerical cases, the DRIM-based algorithm is about 2–10 times faster than the conventional method, which indicates that DRIM has promising applications in large-scale problems.

Electrical resistance based residual strength prediction method for SiC/SiC mini-composites after stress-free oxidation

A stress-free oxidation model considering the microstructural characteristics of SiC/SiC mini-composites was proposed based on the electrical resistance change before and after oxidation. The relationship between the electrical resistance and the thickness of the internal fiber oxide layer was established. The stress-free oxidation tests were carried out at different temperatures for different oxidation times. The results of the oxide layer thickness calculated by the model agree well with those of the SEM observation. Based on the microstructure of tensile fracture after oxidation, the residual strength model of SiC/SiC mini-composites was proposed. The residual strength of the specimens after stress-free oxidation was calculated based on the oxide layer thickness obtained from the model. The error between the calculated and experimental results is within 14.48 %.

Validation of a global method for the simultaneous analysis of polar and non-polar pesticides by online extraction and LC-MS/MS

BackgroundMulti-residue methods for pesticide analysis in food are available for many compounds, but polar pesticides are not generally included due to their specific properties, which include high polarity and low molecular weight. Single residue methods are therefore needed for sample preparation, while chromatographic separation often requires derivatization, ion paring, or dedicated methods suitable for polar compounds, mostly ion chromatography and hydrophilic interaction liquid chromatography (HILIC). These challenges affect the important pesticide glyphosate and the related compounds aminomethylphosphonic acid (AMPA) and glufosinate. There are only a few methods including these compounds in large-scale analysis, mostly complex methods based on multidimensional chromatography. ResultsA new method, for the global online extraction and analysis of pesticides in beer was developed and validated. The method exploited an online trapping device, with reversed-phase (RP) and anion exchange properties, that can trap small molecules from liquid samples. The ion exchange mechanism was used to retain the very polar pesticides glyphosate, AMPA, and glufosinate. The hydrophobic properties of the trapping column were also exploited to trap pesticides suitable for multi-residue investigations. The chromatographic separation was optimized by comparison of HILIC and RP C30, which could separate pesticides, including the polar ones, with modulation by the trapping column after proper selection of the mobile phase composition and basic modifier. The validation for beer provided recoveries in the range 71–112 %, with <15 % RSD, and LOD and LOQ values of 0.02–1 and 0.3–3 μg L−1, respectively. The result was competitive with previous methods on polar pesticide analysis in beer. SignificanceThe method was validated for 15 pesticides, over the log Kow range from −4.4 to 4.5, using a methodology with single and fast chromatographic separation under conditions compatible with multi-residue analysis by RP-LC-MS/MS. In the case of beer, for which the method was validated, the sample preparation was also performed online, after simple degassing, and sample dilution.

A NEW ALGORITHM FOR GENERATING POWER SERIES SOLUTIONS FOR A BROAD CLASS OF FRACTIONAL PDES: APPLICATIONS TO INTERESTING PROBLEMS

This research offers a precise analytical solution for initial value problems of both linear and nonlinear fractional order partial differential equations. A new approach called the limit residual function method is developed and utilized to generate a series solution for the equations. The key tools of this method are the concepts of power series, residual function, and the limit at zero. The new method is characterized by the speed of determining the series solution coefficients and the limited mathematical operations used. The study examines five significant applications of fractional partial differential equations using this new method. To validate the accuracy of the results, they are compared with exact solutions in the classical case for the discussed applications. We conclude that the proposed approach is straightforward, effective, and successful in solving linear and nonlinear fractional differential equations.

On the inverse problem of time dependent coefficient in a time fractional diffusion problem by sinc wavelet collocation method

The object of this study is to establish the unknown function in a time fractional diffusion problem and the solution as well by utilizing Sinc wavelet collocation method (SWCM) and residual power series method (RPSM) together. SWCM enables us to convert time fractional diffusion problem into a system of fractional ordinary differential and algebraic equations. At this stage, the unknown function and the solution are constructed in the series form by employing RPSM. The novelty of this study is that the combination of SWCM and RPSM is utilized to establish the solution of inverse coefficient problem for the first time. Demonstrative examples are presented to articulate the implementation and importance of the proposed method.

Increasing softening point of isotropic spinnable asphalt by two-step preparation from ethylene tar residue modified with bio tar residue

Carbon fiber prepared from asphalt may be a critical type of low-weight chemical material of excellent mechanical performances. Here, an isotropic spinnable asphalt (EBA) was prepared from ethylene tar residue (ETR) by a two-step method of bio tar residue (BTR) through co-polymerization-air blowing, and isotropic asphalt carbon fibers were prepared from the product asphalt. The main types of molecules contained in the two feedstocks were determined by 1H NMR and LDI-TOF MS analyses. The co-polymerization behavior and thermal stability of the asphalt blends were analyzed using polarized light microscopy and thermogravimetric analyzer, respectively. Finally, the morphology and mechanical properties of carbon fibers made from EBA were evaluated by scanning electron microscope and universal testing machine. The results show that BTR contains much more oxygen-containing functional groups and unique long-chain sawtooth molecular structure; the former can promote the reactivity of the co-polymerization reaction, and the latter can limit the formation of large-plane cyclic aromatic hydrocarbon polymers due to the spatial resistance effect to greatly reduce the content of the mesophase. The softening point of the product asphalt shows a tendency of increasing and then decreasing with the increase of the proportion of BTR in the raw material mixture, and a reaction mechanism based on linear and bulky molecules is proposed to explain it by analogy with the structure of macromolecules. Consequently, the EBA made from a mixture of ETR and BTR at ideal moderate proportions has excellent performance in terms of softening point and mesophase content than ETRO made from ETR alone, and the carbon fiber made has a high tensile strength of 1.82 GPa with an elastic modulus of 38.9 GPa, which has reached the level of high tensile strength carbon fiber. Therefore, the use of inexpensive renewable energy bio-asphalt in the modification of heavy oil to obtain high softening point isotropic asphalt for preparing isotropic carbon fiber with excellent properties is achievable.

Thermal distribution and viscous heating of electromagnetic radiative Eyring–Powell fluid with slippery wall conditions

The research examines the intricate between Eyring-Powell microfluidic heat transfer, electromagnetic radiation and viscous heating in a Riga slippery device as applied in heat exchangers, cooling systems, biomedical devices, energy generation, polymer processing, and others. The viscoelastic property of the fluid is characterized by the Eyring-Powell Cauchy fluid model with shear-thickening and shear-thinning phenomena that are useful in several heat transport processes and thermal management. The developed governing model is taken from the constitutive relations and conservation principles and solved via an adaptive partition weighted residual method. The essential fluid term sensitivities are systematically investigated on the flow and thermal distribution characteristics. An appropriate validation and comparison of results is done and found to agree quantitatively, this confirmed the correctness of the presented outcomes. The results reveal the significant impact of the thermofluidic terms interaction on the viscous flowing fluid and thermal behaviour. As seen, slip conditions momentously increase the flow rate gradients for about 1.7% to 2.4% close to the boundary wall and consequently raise the microfluidic thermal propagation rates with 3.7% non-Newtonian fluid and thickness of the boundary layer. Moreover, the thermal gradient and distribution complexities are modulated within the fluid regime due to radiation and Lorentz force.

Krylov subspace methods based quaternion tensor form for generalized Sylvester quaternion tensor equation with application to color video restoration

In this paper, we consider Krylov subspace methods based quaternion tensor form for a class of generalized Sylvester quaternion tensor equation. A novel quaternion tensor product and a global quaternion Arnoldi process based on the tensor form are proposed. Then, the quaternion tensor Krylov subspaces and their orthogonal bases are constructed via the proposed global quaternion Arnoldi process. The quaternion full orthogonalization method based on tensor format (denoted by QFOM−BTF) and the quaternion generalized minimal residual method based on tensor format (denoted by QGMRES−BTF) are established to solve the quaternion tensor equation. The theoretically analyze results of the proposals are discussed on the quaternion tensor form. Finally, we demonstrate the feasibility of QFOM−BTF and QGMRES−BTF methods on some numerical examples including the color video restoration.

A Robust Star Identification Algorithm for Resident Space Object Surveillance

Star identification algorithms can be applied to resident space object (RSO) surveillance, which includes a large number of stars and false stars. This paper proposes an efficient, robust star identification algorithm for RSO surveillance based on a neural network. First, a feature called equal-frequency binning radial feature (EFB-RF) is proposed for guide stars, and a superficial neural network is constructed for feature classification. Then the training set is generated based on EFB-RF. Finally, the remaining stars are identified using a residual star matching method. The simulation experiment and results show that the identification rate of our algorithm can reach 99.82% under 1 pixel position noise, and it can reach 99.54% under 5% false stars. When the percentage of missing stars is 15%, it can reach 99.40%. The algorithm is verified by RSO surveillance.