Present Method Research Articles

Virtual Reality Technology and Artificial Intelligence for Television and Film Animation

Artificial intelligence technology has transformed television content and production methods and resulted in the development of a new generation of artificially intelligent Television. Popularising artificial intelligence technology improves television programme content, categories, cost, and efficiency. Virtual reality (VR) technology has been widely used in scientific study and everyday life; thus, its use in film and television animation (FTA) teaching has been researched to promote FTA learning. First, learning design uses dynamic environment modelling, real-time 3D graphic production, stereoscopic displays, sensors, and other VR technologies. These four issues were researched due to the present FTA primary teaching method. VR technology enhances FTA's basic training teaching, and the 3D animation course and VR technology increase professional skill course teaching. The application effect compares and analyses classroom satisfaction, comprehensive quality evaluation, and professional core curriculum effect. The VR technology group's thorough quality evaluation is significantly improved, and students' satisfaction with classroom atmosphere, teaching style, and teaching facilities is 85%, 78%, and 97.34%, respectively. This group can incorporate the new design process into animation modelling and finish the course design work well. Compared to traditional instruction, pupils are happier and harvest more. Thus, VR technology in FTA instruction can increase student engagement, efficiency, and professional knowledge and abilities. After analysing its application mode and effects, VR technology can be used in FTA teaching.

Addressing arbitrary body forces in 2D elasticity coupling the Radial Basis Integration Method with boundary elements

A boundary-domain integral formulation inevitably arises when the boundary element method (BEM) is applied for solving the differential equation that governs linear elastostatic problems with body forces. Although the domain integrals introduced by the body forces can be evaluated using internal cells this destroys the boundary-only meshing feature of BEM and makes the integration processes inefficient. This paper shows that these problems can be solved more efficiently without using internal cells by the Radial Basis Integration Method (RBIM) which employs a meshless quadrature obtained by performing boundary-only offline computations. Using RBIM, weakly singular domain integrals can be computed via a simple selective quadrature procedure, whereas, strong singular domain integrals may be computed using two schemes: The first, is based on the same selective quadrature procedure, and the second is based on the singularity separation scheme. The present method, unlike classical radial integration method (RIM), does not have problems in calculating integrals in concave or multiple-connected domains. The results obtained in some 2D linear elastostatic problems with arbitrary body forces show that this method can be as accurate as RIM but less time-consuming than the latter. This method could be applied to other engineering problems involving source terms.

Analysis of Electrocardiograms and Behavior in Mice from Pregnancy to Lactation Period.

Changes in the mother-offspring relationship are presumably accompanied by dynamic changes in the autonomic nervous system. Although temporal measurements of autonomic activity have been performed in human mothers and infants, the analysis of long-term changes remains unexplored. Mouse mothers can form social bonds with their pups and have a short period of pregnancy and lactation, which makes them useful for the examination of physiological changes from pregnancy to pup-rearing. Therefore, a telemetry system was used for several weeks to measure the changes in the autonomic nervous system and the behavior of mouse mothers. The current results showed that an electrocardiogram (ECG) could be stably recorded regardless of the movements of mothers and parturition. ECG analysis showed that the heart rate gradually decreased from pregnancy to lactation, and sympathetic activity sharply increased as the pups developed. Furthermore, the simultaneous recording of behavior and ECG in the home cage enabled us to understand the behavior-dependent influences on the ECG, thereby revealing the characteristics of autonomic nervous activity during each behavior. Thus, the present experimental method helps to understand how the physiological characteristics of mothers change from pregnancy through pup rearing, supporting the healthy development of pups.

A boundary point interpolation method for acoustic problems with particular emphasis on the calculation of Cauchy principal value integrals

A boundary point interpolation method (BPIM) is presented in this paper for numerical solving acoustic problems. The BPIM is a boundary-type meshless method that combines the point interpolation technique for constructing approximate functions with boundary integral equations for reformulating boundary value problems. Since effective numerical integration techniques are crucial in the BPIM and boundary integral equation methods for calculating regular and singular integrals, two Clenshaw-Curtis integration techniques (CCITs) for regular and weakly singular integrals are derived in a unified manner with the same integration points on quadratic integration cells. In addition, a unilateral CCIT, a power series expansion technique, and an improved CCIT are proposed to effectively calculate strongly singular integrals or Cauchy principal value integrals in the BPIM. These integration techniques provide direct and efficient formulas for calculating boundary integrals on quadratic integration cells, and can be directly applied to the calculation of regular and singular integrals in the boundary element method and other meshless boundary integral equation methods. Explicit expressions of integration weights in all CCITs are derived, and the values of integration points and weights are listed. Numerical results are finally provided to validate the effectiveness of the present meshless method and integration techniques.

Mode-II stress intensity factors for special-shaped cylindrical shells in torsion

Special-shaped cylindrical shells in torsion are encountered in engineering applications, which will induce the Mode-II singular stress fields next to circumferential crack tips. The Mode-II stress intensity factor (SIF) represents the strength of these singular stress fields and is an important fracture parameter. The crack problems for the cylindrical shells are typical finite boundary value issues. It is very difficult to get the exact solutions by using the classical theory of elasticity. In present article, based on the concepts of the conservation law and the elementary strength theory, a hybrid methodology to determine the Mode-II SIFs for circumferential cracked special-shaped cylindrical shells in torsion is suggested. Due to the introduction of elementary mechanics, the corresponding errors are also inevitably carried into the Mode-II SIFs. However, the finite element analysis indicates that the error of the Mode-II SIFs calculated by present method is acceptable.

A Numerical Method for Unstable Propagation of Damage in Fiber-Reinforced Plastics with an Implicit Static FE Solver

Finite element analyses of the propagation of damage such as fiber compressive failure and delamination have greatly contributed to the understanding of failure mechanisms of fiber-reinforced plastics owing to extensive studies on methodologies using Continuum Damage Mechanics and Fracture Mechanics. Problems without the need for consideration of inertia, such as Double-Cantilever Beam tests, are usually solved by implicit FE solvers, and explicit FE solvers are appropriate for phenomena that progress with very high velocity such as impact problems. However, quasi-static problems with unstable damage propagation observed in experiments such as Open-Hole Compression tests are still not easy to solve for both types of solvers. We propose a method to enable the static FE solver to solve problems with unstable propagation of damage. In the present method, an additional process of convergence checks on the averaged energy release rate of damaged elements is incorporated in a conventional Newton–Raphson scheme. The feasibility of the present method was validated by two numerical examples consisting of analyses of Open-Hole Compression tests and Double-Cantilever Beam tests. The results of the analyses of OHC tests showed that the present method was applicable to problems with unstable damage propagation. In addition, the results from the analyses of DCB tests with the present method indicated that mesh density and loading history are not significantly influential to the solution.

Effect of Variable Viscosity on Entropy Generation Analysis Due to Graphene Oxide Nanofluid Convective Flow in Concentric Cylinders

Aggregated studies of graphene nanoparticles is important for the effective utilization of their striking thermophysical properties and extensive industrial applications. This investigation is one such computational study to explore the flow of graphene oxide nanofluids with temperature dependant viscosity between two concentric cylinders. Buongiorno model is used to develop the flow of graphene nanofluids including the impacts of Soret and Dufour effects and the effects of nanoparticle characteristics such as thermophoresis and Brownian motion. The modelled equations are transformed and are numerically solved using linearization method together with Chebyshev’s spectral collocation method under convective conditions. The impacts of embedded parameters on temperature, concentration and skin friction profiles of the chosen nanofluid and their consequent impacts on the predominant cause for the generated entropy are studied. From the tabulated values of Nusselt number and Sherwood number, it is observed that convective heat transfer can be enhanced by thermal Biot number whereas Soret number enhances diffusive mass transfer and variable viscosity parameter preferably reduces the skin friction. A comparison table is presented and it shows that the values obtained from the present method are in good agreement with existing literature. Also, the obtained results are depicted and interpreted in detail. Furthermore, entropy generation is analysed and its irreversibilty is calculated.

Thermal error modelling and compensation of CNC lathe feed system based on positioning error measurement and decoupling

Thermal error modeling and compensation considering of the measured positioning error decoupling for the lathe with a slant bed is proposed. Due to the complex coupling factors of thermal error, the current compensation methods exhibit limited applicability and generalization. The linear fitting method is used to decouple geometric error and thermal error from the positioning error. The motion heating and non-motion heating experiments of X-direction feed system were carried out to investigate the principle of thermal error generation and the impact factors. The multiple linear regression model of the thermal error was established based on the analysis of the thermal error measurement results. To verify the effectiveness of the proposed model, the thermal error at two working conditions was predicted, and then the error compensation was carried out. The results show that the positioning error is reduced by more than 84% and 92% with the present method compared with that without compensation. This research provides effective method for the generation principle and compensation of thermally induced errors of lathe with a slant bed.

A STABILIZED FINITE ELEMENT METHOD FOR THE STOKES EIGENVALUE PROBLEM

A stabilized finite element method is considered for the Stokes eigenvalue problem based on the lowest equal-order element pair, which does not need to choose stabilization parameter. Stabilization terms of the stabilized finite element method include not only the term related to the momentum equation but also the continuity equation. Furthermore, combined the approximation of compact operator with the analysis of Stokes source problem, error estimates of the present method are deduced. Finally, numerical tests are made to confirm effectively.

Scanning ex situ solid-state magnetic resonance imaging on polymeric films using a static magnetic field gradient by an electromagnet.

A new technique for ex situ solid-state nuclear magnetic resonance imaging of polymeric films has been developed. This method uses the static magnetic field gradient generated by a water-cooled copper electromagnet. The imaging process involves scanning the sample in the plane of the film under a static magnetic field gradient. Two-dimensional (2D) 19F MRI measurements are attempted, where the fast Fourier transform (FFT) spectra of the second half of a Hahn echo peak is used for the depth (X-axis) direction, and the sample film is mechanically moved for the Y-axis, which is in-plane with respect to the film surface and normal to the inter-magnetic-pole line (Z-axis). The sample is a poly(tetrafluoroethylene) [PTFE] film with carved stripes on its surface. Furthermore, three-dimensional (3D) measurements of the film surface and thickness orientations were also performed for an analogous PTFE film. For 2D profiling on the film surface, 2D sample-moving was used. For depth profiling, FFT spectrum analysis was undertaken for each voxel situated at a specific (Y, Z) coordinate within the film. As a result, a 3D image of the sample and its corresponding geometry were obtained, although the scanning area was restricted to a part of the sample. Finally, numerical simulations of the spatial distribution of the static magnetic field were performed to confirm the validity of the present method.

Enhancing Herbage Growth, Yield and Quality of Stevia (Stevia rebaudiana Bertoni) using Bio-Organic Nutrients in Varied Soil Media

The present method of stevia propagation is still insufficient to meet its increasing demand. Moreover, the use of organic inputs as substitutes for inorganic fertilizers to improve soil quality and productivity is also desired. In this study, the effects of bio-organic nutrients and different growing media compositions on Stevia’s herbage growth, yield and quality were determined. A completely randomized design was used with 20 rooted stem cuttings per replication at one cutting per potting bag, laid in a 4 × 4 factorial arrangement. Growing Media (garden soil alone [GS]; GS + rice hull [RH]; GS + vermicompost [VC]; and GS+RH+VC) served as factor A while bio-organic nutrients (fermented fruit juice [FFJ]; vermi tea [VT]; seaweed tea [ST] and control) as factor B. There were 16 treatment combinations replicated four times. Results showed that GS+RH+VC consistently improved the survival rate, plant height, leaf and shoot count per plant, weight (fresh and dry), and herbage yield of Stevia. Furthermore, VT boosted the herbage yield and visual quality. In terms of interaction effects, plants grown in garden soil mixed with vermicompost (GS+VC) with VT application developed more leaves than other treatment combinations. Hence, these bio-nutrients and growing media composition significantly enhanced the production of Stevia.

THEORETICAL ANALYSIS AND NUMERICAL SOLUTION OF LINEAR AND NONLINEAR NEUTRAL DELAY DIFFERENTIAL EQUATIONS

In this paper, a collocation method based on the Haar wavelet is presented for the solution of both linear and nonlinear first-order neutral delay differential equations. The Haar functions are used to approximate the first-order derivative, and the approximate solution is obtained by using initial condition and integration. Some examples from the literature are used to test the suggested method efficiency and applicability. A comparison of exact and approximate solutions is given in figures for different numbers of collocation points. The root mean square and maximum absolute errors are calculated for different numbers of collocation points. The rate of convergence is calculated which is approximately equal to 2. The comparison of the present method with the other numerical methods is also given. The results demonstrate that the Haar wavelet collocation method is simple and effective for solving first-order linear and nonlinear neutral delay differential equations.

Calculation of the ecological and economic effect of collecting rainwater with «green» roofs

The problem of the availability of fresh water on the planet is substantiated and the main concepts of sustainable rainwater management, such as: "SuDS", "BMP", "LID", "GI", as well as the concept of "green" structures, are analyzed. The classification and characteristics of the main types of «green» roofs, as well as their main ecological advantages, are presented. The global market for green roofs is shown growing from USD 1.4 billion in 2020 to a CAGR of 17% from 2020 to 2027, to reach USD 4.2 billion by 2027, and is projected to the extensive type will account for more than half of the total market share. The problem of high costs for installation and maintenance of environmentally friendly solutions for the roof is highlighted, therefore the aim of the work is to calculate the ecological and economic effect of collecting rainwater obtained from "green" roofs, in contrast to traditional roofs, and to conduct an economic analysis of social and cost benefits. what green roofs generate over their life cycle using the Net Present Value (NPV) method. The ecological and economic effect of collecting rainwater with "green" roofs was calculated for four cities of Ukraine: Kyiv, Kharkiv, Dnipro and Lviv. According to the results of calculations, the ecological effect of EE ranges from 394,000 m3 in the city of Dnipro and 450,000 m3 in Kharkiv to 567,000 m3 in Kyiv and 647,000 m3 in Lviv. The difference in the obtained calculations depends primarily on the selected area of "green" roofs, which was the lowest in the city of Dnipro (1.47 million m2) and the highest in the city of Kyiv (2.50 million m2), the values of which were chosen conditionally, as well as from the indicator of the average annual amount of precipitation, which is the highest in the city of Lviv (740 mm). The average value of the ecological effect of EE in relation to water retention in the analyzed cities was calculated, which was 515,000 m3. By multiplying EE and water price, the average ECE for these 4 cities was determined to be $380,500. It was concluded that the price of water is a decisive dependent variable in the calculation of ECE. The calculation of the economic analysis of the profitability of investments in "green" roofs corresponding to 1 m2 of intensive and extensive "green" roofs, which was carried out on the basis of the net present value method (NPV). It is shown that investment costs for "green" roofs include the following stages: design of "green" roofs; installation of the "green" roof system; installation of waterproofing; production of substrate for roofs and its installation; selection and planting of plants on the roof; installation of the irrigation system. It is substantiated that both intensive and extensive "green" roofs have a positive indicator of the net present value of NPV. The average NPV per 1 m2 of an intensive "green" roof is more than 10 times higher than the average NPV per 1 m2 of an extensive "green" roof.

Nonlinear Free Vibration Analysis of Functionally Graded Porous Conical Shells Reinforced with Graphene Nanoplatelets

The nonlinear vibration analysis of functionally graded reinforced with graphene platelet (FG-GRC) porous truncated conical shells surrounded by the Winkler-Pasternak elastic foundation is presented in this paper. An improved model for evaluating the material properties of porous composites is proposed. Three types of porous distribution and three patterns of graphene nanoplatelets (GPLs) dispersion are estimated. Coupled with the effect of the Winkler-Pasternak elastic foundation, the nonlinear governing equations are developed by using the Hamilton principle. The Galerkin integrated technique is employed to obtain the linear and nonlinear frequencies of the shells. After the present method is validated, the effects of the pores, GPLs, the Winkler-Pasternak foundation, and the semi-vertex are investigated in detail. The results show that the linear frequency can be raised by increasing the values of the mass volume of the GPL and foundation parameters. In contrast, the ratio of nonlinear to linear frequency declines as the mass volume of the GPLs and foundation parameters rises. Furthermore, it is found that the minimum ratio of nonlinear to linear frequency can be obtained as the semi-vertex angle is about 55º, and the effect of porosity distribution on the linear and linear frequencies might be neglected.

A new set of explicit solutions for postbuckling behaviour of anisotropic shear deformable laminated cylindrical shells with general imperfection distribution and thermal loading

Thermal postbuckling analysis is presented for shear-deformable anisotropic laminated cylindrical shell with general imperfection distribution under several typical temperature fields are analyzed, including uniform temperature, tent-like linear distribution, axial and circumferential quadratic parabolic temperature fields over the shell surface and through the shell thickness. On this basis, the general temperature distribution can be obtained based on the three-dimensional steady-state heat transfer equation. At the same time, based on the high order shear deformation theory including anisotropic coupling effect, geometrically nonlinear large deflection displacement-strain relationship, the general initial geometric imperfections obtained by measurement and analytical means are introduced, and the thermal buckling equilibrium differential equation of anisotropic shear deformable laminated cylindrical shell with initial imperfections is established. A two-step perturbation-Galerkin integral method is used to obtain explicit solutions for the path development direction of post-thermal buckling equilibrium. The results of parameter analysis show that the material properties and temperature dependence, temperature distribution, lay-up and geometric parameters such as radius-to-thickness ratio have important effects on the thermal buckling load and postbuckling equilibrium path. The present method provides an effective theoretical prediction and analysis method for the design of the carrying capacity of submarine pipelines.

Medical image segmentation network based on multi-scale frequency domain filter

With the development of deep learning, medical image segmentation in computer-aided diagnosis has become a research hotspot. Recently, UNet and its variants have become the most powerful medical image segmentation methods. However, these methods suffer from (1) insufficient sensing field and insufficient depth; (2) computational nonlinearity and redundancy of channel features; and (3) ignoring the interrelationships among feature channels. These problems lead to poor network segmentation performance and weak generalization ability. Therefore, first of all, we propose an effective replacement scheme of UNet base block, Double residual depthwise atrous convolution (DRDAC) block, to effectively improve the deficiency of receptive field and depth. Secondly, a new linear module, the Multi-scale frequency domain filter (MFDF), is designed to capture global information from the frequency domain. The high order multi-scale relationship is extracted by combining the depthwise atrous separable convolution with the frequency domain filter. Finally, a channel attention called Axial selection channel attention (ASCA) is redesigned to enhance the network’s ability to model feature channel interrelationships. Further, we design a novel frequency domain medical image segmentation baseline method FDFUNet based on the above modules. We conduct extensive experiments on five publicly available medical image datasets and demonstrate that the present method has stronger segmentation performance as well as generalization ability compared to other state-of-the-art baseline methods.

Metaheuristic optimized time–frequency features for enhancing Alzheimer’s disease identification

Background:Alzheimer’s disease (AD) is a chronic disorder characterized by progressive cognitive dysfunctions and memory loss. Electroencephalography (EEG) is a non-invasive tool to detect AD using machine learning models and signal-derived features. Feature selection enhances AD detection performance, reduces training and testing time, and builds simpler models. Metaheuristic algorithms (MHAs) have successfully selected optimum features in several classification tasks and can be valuable in enhancing AD detection. Method:In this work, an AD detection model is proposed based on a systematic investigation of adaptive signal decomposition techniques and MHAs. The four techniques comprising empirical mode decomposition, variational mode decomposition, discrete wavelet transform, and Low-Complexity Orthogonal Wavelet Filter Banks (LCOWFBs) decompose EEG signals into subbands. Thirty-four features based on signal, temporal, spectral, and entropy analysis are extracted for each subband. The salient features are selected using seven different MHAs: particle swarm algorithm, salp swarm algorithm, reptile search (RSA), Grey Wolf, dwarf mongoose optimization, snake optimizer, and Fick’s law algorithm (FLA). Results:The two publicly available AD EEG datasets validated the performance of the proposed framework. LCOWFBs achieved the highest binary classification accuracy of 99.72% using 15 salient features selected by RSA and multi-class accuracy of 88.92% with seven salient features selected by FLA. The present method investigates brain regions that are affected by AD. Conclusion:The results indicate that the combination of LCOWFBs and RSA achieved maximum AD detection performance for both datasets with shorter computational time than earlier reported methods in the literature. The present model can be extended to identify chronic disorders, including hypertension, sleep disorders, and Parkinson’s disease.

Boosting optoelectronic performance of (FA)X(MA)1-XPbI3 perovskite solar cells: Via FAI post-treatment engineering

Complex composition engineering of mixed-cations perovskite (FAxMA1-xPbI3) has recently supported rapid progress in perovskite solar cells (PSCs). Nevertheless, it is insufficient to embed and accommodate formamidinium (FA) cation into the MAPbI3 lattice structure via existing methods, leaving behind masses of FA or lead halide content and deteriorating photovoltaic performance. Herein, we present facile surface engineering via post-treated methodology, the surface of CH3NH3PbI3 (MAPbI3) films post-treated with formamidinium iodide (FAI) solution and that results get mixed-cation FAxMA1-xPbI3 perovskite films. The mixed-cation-based FAXMA1-XPbI3 perovskite with significant and large grain size, uniform and compact morphology, highly crystallization, and consequently reducing defect density of the perovskite films can be produced via the present method. It is observed that the film, post-treated with FAI-2, shows results in a very stable and highly crystalline lattice structure with attributes such as extended carrier lifetime, better electron transport, and decreased defect density. The optimized device demonstrates a promising power conversion efficiency (PCE) of 21.89%, and higher than that of the non-treated (19.08%) devices. Furthermore, the devices based on the novel FAI-post-treatment engineering exhibit significantly enhanced stability compared to non-treated devices. Therefore, this approach provides a novel methodology that offers a simple method for producing superior mixed perovskite films, potentially paving the way for the future exploitation of the boosted performance of perovskite solar cells.

Synthesis of 3‐Arylazoindoles through Iron(III)‐Catalyzed C−H Azolation of Indoles and Arylhydrazines

AbstractA variety of functionalized 3‐arylazoindoles were prepared in good to excellent yields through an iron(III)‐catalyzed C−H azolation of 2‐substituted indoles with arylhydrazines under mild reaction conditions. The reaction underwent an initial TBN‐mediated nitrosation, 1,5‐hydrogen migration, intramolecular condensation, and 1,5‐hydrogen migration over four steps in one pot. A paracyclophane‐derived 3‐phenylazoindole could be prepared in 25% yield over three steps and some prepared 3‐arylazoindoles showed a different fluorescence emission wavelength and existed obvious pH conditions response. The present method highlights broad substrate scope of easily available starting materials, wide range of functional group compatibility, gram scalable preparations, high atom economy, avoidance of unstable and explosive azolation reagents, and simple purification operations by extraction, washing, and recrystallization without flash column chromatography.

Measuring Respirable Crystalline Silica (Quartz) from Powdery Materials through Sedimentation and X-ray Diffractometry.

When possible, choosing materials with a low quartz content is the most effective and cost-efficient way to prevent the respirable quartz exposure of workers and other end users of powdery products. Therefore, methods are needed to analyze low amounts of quartz from powdery products, such as sand, gravel, plaster, cement, and concrete. To this end, we present a method to analyze respirable dust and quartz from powdered materials, such as construction products. The method includes separation of the respirable dust fraction by liquid sedimentation, followed by gravimetric analysis and determination of the crystalline silica content by X-ray diffractometry. While also aiding in the development of less harmful products, analysis of the quartz concentration of powdery products is statutory in Eu countries, excluding natural products not chemically modified. According to EU Regulation No. 1272/2008, products must be classified if they contain harmful substances in concentrations above 0.1 wt.%, and clauses pertaining to cancerous properties and harmfulness to lungs should be included. Also, mineral producers in the EU recommend that products containing respirable quartz should be labelled based on their quartz concentration, provided the concentration exceeds 1 wt.%. The present method meets these needs. The analysis can be performed in parallel from 50 to 1000 mg (dry weight) of powdery materials. The quantitative limit of determination was 10 µg per sample, corresponding to 0.01 wt.%, and the linear range 0.02-10 wt.% (10-5000 µg quartz per sample, Pearson correlation coefficient 0.99). The accuracy of the method was 82% and the repeatability 11%.