Mathematical and Computational Applications最新文献_第5页

Free Vibration Analysis of Porous Functionally Graded Material Plates with Variable Thickness on an Elastic Foundation Using the R-Functions Method 使用 R 函数法对弹性地基上厚度可变的多孔功能分层材料板进行自由振动分析

Mathematical and Computational Applications Pub Date : 2024-01-29 DOI: 10.3390/mca29010010

L. Kurpa, F. Pellicano, Tetiana V. Shmatko, A. Zippo

{"title":"Free Vibration Analysis of Porous Functionally Graded Material Plates with Variable Thickness on an Elastic Foundation Using the R-Functions Method","authors":"L. Kurpa, F. Pellicano, Tetiana V. Shmatko, A. Zippo","doi":"10.3390/mca29010010","DOIUrl":"https://doi.org/10.3390/mca29010010","url":null,"abstract":"Free vibrations of porous functionally graded material (FGM) plates with complex shapes are analyzed by using the R-functions method. The thickness of the plate is variable in the direction of one of the axes. Two types of porosity distributions through the thickness are considered: uniform (even) and non-uniform (uneven). The elastic foundation is defined by two parameters (Winkler and Pasternak). To obtain the mathematical model of the problem, the first-order shear deformation theory of the plate (FSDT) is used. The effective material properties in the thickness direction are modeled by means of a power law. Variational Ritz’s method joined with the R-functions theory is used for obtaining a semi-analytical solution of the problem. The approach is applied to a number of case studies and validated by means of comparative analyses carried out on rectangular plates with a traditional finite element approach. The proof of the efficiency of the approach and its capability to handle actual engineering problems is fulfilled for FGM plates having complex shapes and various boundary conditions. The effect of different parameters, such as porosity distribution, volume fraction index, elastic foundation, FGM types, and boundary conditions, on the vibrations is studied.","PeriodicalId":352525,"journal":{"name":"Mathematical and Computational Applications","volume":"76 35","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Estimating Surface EMG Activity of Human Upper Arm Muscles Using InterCriteria Analysis 利用标准间分析估算人体上臂肌肉的表面肌电图活动

Mathematical and Computational Applications Pub Date : 2024-01-23 DOI: 10.3390/mca29010008

S. Angelova, Maria Angelova, R. Raikova

{"title":"Estimating Surface EMG Activity of Human Upper Arm Muscles Using InterCriteria Analysis","authors":"S. Angelova, Maria Angelova, R. Raikova","doi":"10.3390/mca29010008","DOIUrl":"https://doi.org/10.3390/mca29010008","url":null,"abstract":"Electromyography (EMG) is a widely used method for estimating muscle activity and could help in understanding how muscles interact with each other and affect human movement control. To detect muscle interactions during elbow flexion and extension, a recently developed InterCriteria Analysis (ICrA) based on the mathematical formalisms of index matrices and intuitionistic fuzzy sets is applied. ICrA has had numerous implementations in different fields, including biomedicine and quality of life; however, this is the first time the approach has been used for establishing muscle interactions. Six human upper arm large surface muscles or parts of muscles responsible for flexion and extension in shoulder and elbow joints were selected. Surface EMG signals were recorded from four one-joint (pars clavicularis and pars spinata of m. deltoideus [DELcla and DELspi, respectively], m. brachialis [BRA], and m. anconeus [ANC]) and two two-joint (m. biceps brachii [BIC] and m. triceps brachii-caput longum [TRI]) muscles. The outcomes from ten healthy subjects performing flexion and extension movements in the sagittal plane at four speeds with and without additional load are implemented in this study. When ICrA was applied to examine the two different movements, the BIC–BRA muscle interaction was distinguished during flexion. On the other hand, when the ten subjects were observed, four interacting muscle pairs, namely DELcla-DELspi, BIC-TRI, BIC-BRA, and TRI-BRA, were detected. The results obtained after the ICrA application confirmed the expectations that the investigated muscles contribute differently to the human upper arm movements when the flexion and extension velocities are changed, or a load is added.","PeriodicalId":352525,"journal":{"name":"Mathematical and Computational Applications","volume":"125 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139605003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Multi-Credit-Rating Migration Model with Asymmetric Migration Boundaries 具有不对称迁移边界的多信用等级迁移模型

Mathematical and Computational Applications Pub Date : 2024-01-17 DOI: 10.3390/mca29010007

Yang Lin, Jin Liang

引用次数: 0

A Numerical Method Based on Operator Splitting Collocation Scheme for Nonlinear Schrödinger Equation 基于非线性薛定谔方程的算子分割配位方案的数值方法

Mathematical and Computational Applications Pub Date : 2024-01-15 DOI: 10.3390/mca29010006

Mengli Yao, Zhifeng Weng

引用次数: 0

Accuracy Examination of the Fourier Series Approximation for Almost Limiting Gravity Waves on Deep Water 深水几乎极限重力波的傅里叶级数近似值精度检验

Mathematical and Computational Applications Pub Date : 2024-01-11 DOI: 10.3390/mca29010005

Yang-Yih Chen, Hsien-Kuo Chang

引用次数: 0

Role Reversals in a Tri-Trophic Prey–Predator Interaction System: A Model-Based Study Using Deterministic and Stochastic Approaches 三营养捕食者-捕食者相互作用系统中的角色逆转：使用确定性和随机方法进行的基于模型的研究

Mathematical and Computational Applications Pub Date : 2024-01-10 DOI: 10.3390/mca29010003

Sk Golam Mortoja, Ayan Paul, P. Panja, Sabyasachi Bhattacharya, S. Mondal

{"title":"Role Reversals in a Tri-Trophic Prey–Predator Interaction System: A Model-Based Study Using Deterministic and Stochastic Approaches","authors":"Sk Golam Mortoja, Ayan Paul, P. Panja, Sabyasachi Bhattacharya, S. Mondal","doi":"10.3390/mca29010003","DOIUrl":"https://doi.org/10.3390/mca29010003","url":null,"abstract":"It is frequently observed that adult members of prey species sometimes use their predation mechanism on juvenile members of predator species. Ecological literature describes this phenomenon as prey–predator role reversal dynamics.Numerous authors have observed and described the biological development behind this feeding behaviour. However, the dynamics of this role reversal have hardly been illustrated in the literature in a precise way. In this regard, we formulated an ecological model using the standard prey–predator interactions, allowing for a reverse feeding mechanism. The mathematical model consisted of a three-species food-web structure comprising the common prey, intermediate predator, and top predator. Note that a role-reversal mechanism was observed between the intermediate and top predators based on the scarcity of the prey population. However, we observed the most critical parameters had a significant effect on this reverse feeding behaviour. The bifurcation analysis is the primary criterion for this identification. The proposed deterministic model is then extended to its stochastic analogue by allowing for environmental influences on the tri-trophic food web structure. The conditional moment approach is applied to obtain the equilibrium distribution of populations and their conditional moments in the system. The stochastic setup analysis also supports the stability of this food chain structure, with some restricted conditions. Finally, to facilitate the interpretation of our mathematical results, we investigated it using numerical simulations.","PeriodicalId":352525,"journal":{"name":"Mathematical and Computational Applications","volume":"82 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139440389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Accelerating Convergence for the Parameters of PV Cell Models 加快光伏电池模型参数的收敛速度

Mathematical and Computational Applications Pub Date : 2024-01-10 DOI: 10.3390/mca29010004

L. Jäntschi, M. Louzazni

引用次数: 0

A Finite Difference Method for Solving the Wave Equation with Fractional Damping 求解带有分数阻尼的波方程的有限差分法

Mathematical and Computational Applications Pub Date : 2023-12-29 DOI: 10.3390/mca29010002

Manruo Cui, Cui-Cui Ji, Weizhong Dai

引用次数: 0

Simulation of a Thermal Recuperative Incinerator of VOCs with a Special Focus on the Heat Exchanger 模拟挥发性有机化合物热回收焚烧炉，特别关注热交换器

Mathematical and Computational Applications Pub Date : 2023-12-23 DOI: 10.3390/mca29010001

Francisco Zdanowski, I. Malico, P. Canhoto, Rui Pedro Lima

{"title":"Simulation of a Thermal Recuperative Incinerator of VOCs with a Special Focus on the Heat Exchanger","authors":"Francisco Zdanowski, I. Malico, P. Canhoto, Rui Pedro Lima","doi":"10.3390/mca29010001","DOIUrl":"https://doi.org/10.3390/mca29010001","url":null,"abstract":"Simulation and modeling of thermal recuperative incinerators may play an important role in enhancing efficiency and ensuring compliance with environmental regulations. In this context, the primary objective of this study is to simulate and comprehensively understand the operation of a geometrically complex thermal recuperative incinerator with an integrated preheater featuring varying levels of heat recovery. To achieve this objective, a simple yet effective 0D model was developed. This modeling approach allows for a holistic evaluation of the performance of the incinerator, enabling the assessment of key parameters, such as temperatures and heat transfer rates, under varying operating conditions. Successful validation of the model is established by comparing its results with measurements from an industrial thermal recuperative incinerator in operation at a vehicle assembly plant, with maximum relative differences of around 9%. Simulations for different percentages of flue gases bypassing the preheater were conducted, indicating a good compromise between heat transfer and pressure drop and a 22% heat recovery at around 50%. The model presented in this paper provides a robust foundation for comprehensively assessing and optimizing the performance of thermal recuperative incinerators and systems that comprise thermal recuperative incinerators, with implications for waste management and sustainable energy recovery systems.","PeriodicalId":352525,"journal":{"name":"Mathematical and Computational Applications","volume":"13 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139161577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Continuum and Molecular Modeling of Chemical Vapor Deposition at Nano-Scale Fibrous Substrates 纳米级纤维基底化学气相沉积的连续和分子建模

Mathematical and Computational Applications Pub Date : 2023-12-06 DOI: 10.3390/mca28060112

Himel Barua, A. Povitsky

{"title":"Continuum and Molecular Modeling of Chemical Vapor Deposition at Nano-Scale Fibrous Substrates","authors":"Himel Barua, A. Povitsky","doi":"10.3390/mca28060112","DOIUrl":"https://doi.org/10.3390/mca28060112","url":null,"abstract":"Chemical vapor deposition (CVD) is a common industrial process that incorporates a complex combination of fluid flow, chemical reactions, and surface deposition. Understanding CVD processes requires rigorous and costly experimentation involving multiple spatial scales, from meters to nanometers. The numerical modeling of deposition over macro-scale substrates has been conducted in the literature and results show compliance with experimental data. For smaller-scale substrates, where the corresponding Knudsen number is larger than zero, continuum modeling does not provide accurate results, which calls for the implementation of molecular-level modeling techniques. In the current study, the finite-volume method (FVM) and Direct Simulation Monte Carlo (DSMC) method were combined to model the reactor-scale flow with CVD around micro- and nano-scale fibers. CVD at fibers with round cross-sections was modeled in the reactor, where fibers were oriented perpendicularly with respect to the feedstock gas flow. The DSMC method was applied to modeling flow around the matrix of nano-scale circular individual fibers. Results show that for smaller diameters of individual fibers with the same filling ratio, the residence time of gas particles inside the fibrous media reduces, and, consequently, the amount of material surface deposition decreases. The sticking coefficient on the fibers’ surface plays an important role; for instance, increasing the sticking coefficient from 20% to 80% will double the deposition rate.","PeriodicalId":352525,"journal":{"name":"Mathematical and Computational Applications","volume":"59 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138595425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0