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Evaluating Effect of Magnetic Field on Nusselt Number and Friction Factor of Fe 3 O 4 -TiO 2 /Water Nanofluids in Heat-Sink Using Artificial Intelligence Techniques

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Frontiers in Heat and Mass Transfer 2025年第1期23卷 131-162页

作者： L. S. Sundar Sérgio M. O. tavares António M. B. Pereira Antonio C. M. Sousa Centre for Mechanical Technology and Automation Department of Mechanical EngineeringUniversity of AveiroAveiro3810-131Portugal

The experimental analysis takes too much time-consuming process and requires considerable effort, while, the Artificial Neural Network (ANN) algorithms are simple, affordable, and fast, and they allow us to make a relevant analysis in establishing an appropriate relationship between the input and output parameters. This paper deals with the use of back-propagation ANN algorithms for the experimental data of heat transfer coefficient, Nusselt number, and friction factor of water-based Fe 3 O 4 -TiO 2 magnetic hybrid nanofluids in a mini heat sink under magnetic fields. The data considered for the ANN network is at different Reynolds numbers (239 to 1874), different volume concentrations (0% to 2.0%), and different magnetic fields (250 to 1000 G), respectively. Three types of ANN back-propagation algorithms Levenberg-Marquardt (LM), Broyden-Fletcher-Goldfarb-Shanno Quasi Newton (BFGS), and Variable Learning Rate Gradient Descent (VLGD) were used to train the heat transfer coefficient, Nusselt number, and friction factor data, respectively. The ANOVA t -test analysis was also performed to determine the relative accuracy of the three ANN algorithms. The Nusselt number of 2.0% vol. of Fe 3 O 4 -TiO 2 hybrid nanofluid is enhanced by 38.16% without a magnetic field, and it is further enhanced by 88.93% with the magnetic field of 1000 Gauss at a Reynolds number of 1874, with respect to the base fluid. A total of 126 datasets of heat transfer coefficient, Nusselt number, and friction factor were used as input and output data. The three ANN algorithms of LM, BFGS, and VLGD, have shown good acceptance with the experimental data with root-mean-square errors of 0.34883, 0.25341, and 1.0202 with correlation coefficients (R 2 ) of 0.99954, 0.9967, and 0.94501, respectively, for the Nusselt number data. Moreover, the three ANN algorithms predict root-mean-square errors of 0.001488, 0.005041, and 0.006924 with correlation coefficients (R 2 ) of 0.99982, 0.99976, and 0.99486, respect

关键词： Artificial neural network nusselt number friction factor heat sink correlations

Increasing Powers in a Degenerate Parabolic Logistic Equation

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Chinese Annals of Mathematics,Series B 2013年第2期34卷 277-294页

作者： Jos Francisco RODRIGUES Hugo tavares Department of Mathematics and CMAF Universidade de LisboaAvenida Professor Gama Pinto 21649-003 LisboaPortugal

The purpose of this paper is to study the asymptotic behavior of the positive solutions of the problem tu- △u=au-b（x）up in Ω×R＋,u（0）=u0,u（t ）｜ Ω=0, as p→ ＋∞, where Ω is a bounded domain, and b（x） is a nonnegative function. The authors deduce that the limiting configuration solves a parabolic obstacle problem, and afterwards fully describe its long time behavior.

关键词： Parabolic logistic equation Obstacle problem Positive solution Increasing power Subsolution and supersolution

A Novel Iterative Velocity Control Algorithm and Its FPGA Implementation Based on Trigonometric Function

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Chinese Journal of Electronics 2019年第2期28卷 237-245页

作者： WEN Quangang LIANG Yanchun Adriano tavares Ricardo Teixeira WU Chunguo Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education College of Computer Science and Technology Jilin University Zhuhai Laboratory of Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education Zhuhai College of Jilin University Department of Industrial Electronics University of Minho Campus de Azurm

The servo motor’s flexible acceleration/deceleration(acc/dec) control is an emerging research topic in the automation field. A velocity control algorithm based on trigonometric function is proposed in this *** required parameters, it transforms trigonometric calculations into elementary mathematical operations and calculates the velocity controlling values iteratively, which could avoid trigonometric calculation and reduce the computation time. Experimental results show that the proposed algorithm is suitable for implementation on field programmable gate arrays and achieves a flexible controlling, enhancing both the equipment’s stability and reliability. It is promising to significantly improve the high-speed computerized numerical control equipment’s controlling accuracy, without a huge hardware resource consumption.

关键词： Acceleration Velocity control Algorithm design and analysis Field programmable gate arrays Servomotors

Constrained Fractional Variational Problems of Variable Order

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IEEE/CAA Journal of Automatica Sinica 2017年第1期4卷 80-88页

作者： Dina tavares Ricardo Almeida Delfim F.M.Torres Department of Mathematics Polytechnic Institute of Leiria Department of Mathematics University of Aveiro

Isoperimetric problems consist in minimizing or maximizing a cost functional subject to an integral *** this work, we present two fractional isoperimetric problems where the Lagrangian depends on a combined Caputo derivative of variable fractional order and we present a new variational problem subject to a holonomic constraint. We establish necessary optimality conditions in order to determine the minimizers of the fractional problems. The terminal point in the cost integral,as well as the terminal state, are considered to be free, and we obtain corresponding natural boundary conditions.

关键词： Fractional calculus fractional calculus of variations holonomic constraints isoperimetric constraints optimization variable fractional order

Implementation of a High-Risk Outpatient Clinic for Children with Complex Congenital Heart Disease in a Reference Service in Brazil

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Congenital Heart Disease 2023年第6期18卷 649-656页

作者： Gustavo Foronda Vanessa Ferreira Amorim de Melo Claudia Regina Pinheiro de castro Grau Ingrid Magatti Piva Glaucia Maria Penha tavares Ana Cristina Sayuri Tanaka Nana Miura Department of Pediatric Cardiology and Adult Congenital Heart Diseases Heart Institute of the University of São PauloSão PauloBrazil Foronda Clinic São PauloBrazil Institute of Orthopedics and Traumatology University of São PauloSão PauloBrazil Department of Echocardiography Heart Institute of the University of São PauloSão PauloBrazil

Background:Children with congenital heart disease(CHD),even after surgical approaches,and especially those who undergo staged procedures in theﬁrst months of life,remain vulnerable to readmissions and complications,requiring very close monitoring and differentiated intervention ***:Descriptive and exploratory study,of the experience report type,which presents the process of building the high-risk outpatient clinic for complex congenital heart diseases(AAR)at the Instituto do Coração(InCor).Results:Report of the path taken to structure the AAR,demonstrating the organization,interface with the multidisciplinary team,admission and discharge criteria,training,and patient proﬁ*** theseﬁve years of care,275 patients were treated,59.65%with biventricular interstage physiology,followed by univentricular interstage physiology(34.55%),residual defects after surgical procedures(3.63%),tumors with risk of mechanical obstruction(1.45%)and patients with an intrauterine approach(0.72%).The signiﬁcant number of critical patients who were successfully discharged from hospital(44.72%),the low mortality rate due to sudden deaths at home and the high adherence to follow-up cor-roborate the impact of this specialized ***:Despite the limitations of the study,this experi-ence report showed that with few resources,there is the possibility of organizing an AAR with differentiated care,with the objective of early detection and treatment of residual injuries,identiﬁcation of early interventions,edu-cation of parents for follow-up of their children,resulting in individualized treatment,promoting a better quality of life for this population.

关键词： Congenital heart defects ambulatory care heart defects

A Survey on Performance Optimization of High-Level Synthesis Tools

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Journal of Computer Science & Technology 2020年第3期35卷 697-720页

作者： Lan Huang Da-Lin Li Kang-Ping Wang Teng Gao Adriano tavares College of Computer Science and Technology Jilin UniversityChangchun 130012China Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun 130012China Zhuhai Laboratory of Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education Zhuhai College of Jilin University Zhuhai 519041China Algorithm Center University of MinhoGuimaraes 4800058Portugal

Field-programmable gate arrays(FPGAs)have recently evolved as a valuable component of the heterogeneous *** register transfer level(RTL)design flows demand the designers to be experienced in hardware,resulting in a possible failure of ***-level synthesis(HLS)permits designers to work at a higher level of abstraction through synthesizing high-level language programs to RTL *** provides a promising approach to solve these ***,the performance of HLS tools still has *** example,designers remain exposed to various aspects of hardware design,development cycles are still time consuming,and the quality of results(QoR)of HLS tools is far behind that of RTL *** this paper,we survey the literature published since 2014 focusing on the performance optimization of HLS *** with previous work,we extend the scope of the performance of HLS tools,and present a set of three-level evaluation criteria,covering from ease of use of the HLS tools to promotion on specific metrics of *** also propose performance evaluation equations for describing the relation between the performance optimization and the *** find that it needs more efforts on the ease of use for efficient HLS *** suggest that it is better to draw an analogy between the HLS development process and the embedded system design process,and to provide more elastic HLS methodology which integrates FPGAs virtual machines.

关键词： evaluation criterion field-programmable gate array(FPGA) high-level synthesis(HLS) performance optimization quality of results(QoR)

Recent advances in lung-on-a-chip technology for modeling respiratory disease

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Bio-Design and Manufacturing 2023年第5期6卷 563-585页

作者： Jorge A.tavares-Negrete Prativa Das Sahar Najafikhoshnoo Steven Zanganeh Rahim Esfandyarpour Department of Electrical Engineering University of CaliforniaIrvineCA 92697USA Department of Biomedical Engineering University of CaliforniaIrvineCA 92697USA Henry Samueli School of Engineering University of CaliforniaIrvineCA 92697USA Laboratory for Integrated Nano Bio Electronics Innovation Henry Samueli School of EngineeringUniversity of CaliforniaIrvineCA 92697USA Department of Mechanical and Aerospace Engineering University of CaliforniaIrvineCA 92697USA Department of Bioengineering University of Massachusetts DartmouthDartmouthMAUSA

Tissue engineering approaches,including those to functional lung tissues,are finely honed by the inclusion of upgraded devices that mimic biophysical and biochemical features in *** culture is one of these essential biophysical characteristics enabled by the introduction of microfluidic devices in recent *** review links the importance of dynamic culture for in vitro maintenance of functional lung cells to the modeling of respiratory *** identify and discuss different parameters for fabricating the requisite microfluidic models for lung cells,as well as their application in modeling lung diseases caused by external factors such as smoking and *** possibility of creating a multi-organ-on-a-chip to establish a more physiologically relevant model is ***,the focus is on different prospects for the in vitro modeling approach and for lungs-on-a-chip for developing advanced,reliable technology to analyze the pathophysiology of respiratory diseases and screen potential treatments.

关键词： Lung-on-a-chip In vitromodeling Lung pathophysiology Respiratory diseases 3D culturemodel

Chromomagnetic and chromoelectric dipole moments of quarks in the reduced 331 model

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Chinese Physics C 2021年第11期45卷 11-24页

作者： A.I.Hemandez-Juarez G.tavares-Velasco A.Moyotl Facultad de Ciencias Fisico Matematicas Benemerita Universidad Autonoma de PueblaApartado Postal 1152PueblaPueblaMexico Ingenieria en Mecatronica Universidad Politecnica de PueblaTercer Carril del Ejido Serrano s/nSan Mateo CuanalaJuan C.BonillaPueblaPueblaMexico

The one-loop contributions to the chromomagnetic dipole momentˆμt(q2)and electric dipole momentˆd t(q2)of the top quark are calculated within the reduced 331 model(RM331)for non-zero *** is argued that the results are gauge independent and thus represent valid observable *** the RM331,ˆμt(q2)receives new contributions from two heavy gauge bosons,namely Z′and V±,and one neutral scalar boson h2,along with a new contribution from the standard model's Higgs boson via flavor changing neutral *** latter,which is also mediated by the Z′gauge boson and the scalar boson h2,can provide a non-vanishingˆd t(q2)if there is a CP-violating *** analytical results are presented in terms of both Feynman parameter integrals and Passarino-Veltman scalar functions,which are useful to cross-check the numerical ***ˆμt(q2)andˆd t(q2)are numerically evaluated for parameter values still allowed by the constraints from experimental *** is found that the new one-loop contributions of the RM331 to the real(imaginary)part ofˆμt(q2)are of the order of 10−5(10−6),which means at least three orders of magnitude smaller than the standard model prediction but larger than the predictions of other models of new *** the RM331,the dominant contribution arises from the V±gauge boson for‖q‖in the 30-1000 GeV interval and a mass mV of the order of a few hundreds of *** forˆd t(q2),it receives its largest contribution from h2 exchange and can reach values of the order of 10−19,i.e.,smaller than the contributions predicted by other standard model extensions.

关键词： chromomagnetic chromoelectric 331 models

Simultaneous binding of folic acid and lutein to β-lactoglobulin and α-lactalbumin: A spectroscopic and molecular docking study

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Food Bioscience 2022年第6期50卷 973-981页

作者： Danilo C.Vidotto Guilherme M.tavares Department of Food Science and Nutrition School of Food EngineeringUniversity of Campinas (UNICAMP)CampinasBrazil

Whey proteins are versatile molecules with great nutritional value and multiple functionalities. One of these functionalities is the ability to bind and protect bioactive compounds. Lutein and folic acid (FA) are bioactive molecules with a remarkable relevance for developing functional foods. FA contributes in preventing the occurrence of neural tube defects during the early stages of life, while lutein is a macular pigment that contributes to the development of the retina. In this context, the aim of this work was to evaluate the ability of the main whey proteins, β-lactoglobulin and α-lactalbumin, to simultaneously bind FA and lutein. The binding was evaluated through intrinsic fluorescence quenching and molecular docking, and the impact of the binding on the secondary structure and denaturation temperature of the proteins were also evaluated through circular dichroism and differential scanning calorimetry, respectively. Both proteins had similar behavior on the performed analyses. The multi-binding ability of β-lactoglobulin and α-lactalbumin to FA and lutein was observed. The presence of the first ligand slightly reduced the association constant between the second one and the proteins;in particular for the binding of lutein in the presence of FA (reduction of around 36%–38% on the KSV values). Molecular docking indicated that both ligands interact, preferentially, on the same region of the studied protein structures. The secondary structure of the proteins, as well as their denaturation temperatures were minimally impacted by the presence of these ligands, themselves. Our results may contribute to the development of multi-functional protein-rich food products.

关键词： Whey proteins Multi-binding Folic acid Lutein Fluorescence quenching Molecular modeling