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14th European Conference on Product and Process Modelling, ECPPM 2022

作者： Châteauvieux-Hellwig, C. Abualdenien, J. Borrmann, A. Centre for Research Development and Technology Transfer Rosenheim Technical University of Applied Sciences Germany Computational Modeling and Simulation Technical University of Munich Germany

ISBN: (纸本)9781032406732

More and more architects and planners are choosing timber in construction because of its sustainability. However, timber elements have low mass, consist of multi-layered structures, and require complex junctions which makes the design process and construction challenging. The design of the junctions influences the sound insulation quality of a building and affects the quality of life for the inhabitants. To save time and cost, the detailed information on junctions should be included already in the early phases of the design process. In this paper, we present an improved building information modelling (BIM) workflow for timber construction. We develop new entities, relations, and property sets with detailed information on junctions that can be included in a BIM model using Industry Foundation Classes (IFC). These improvements will allow the designers to incorporate an acoustic data model that forms the basis for further prognoses of the airborne and impact sound insulation already in early design phases which in turn will reduce time and cost, and improve the quality of the design and the overall design process. © 2023 the Author(s).

关键词： Timber

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Three-dimensional boundary layer flow and heat/mass transfer through stagnation point flow of hybrid nanofluid

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Journal of Engineering and applied Science 2024年第1期71卷 57页

作者： Ferdows, Mohammad Shamshuddin, M.D. Rashad, Ahmed Mohammed Murtaza, Md Gulum Salawu, Sulyman Olakunle Research Group of Fluid Flow Modeling and Simulation Department of Applied Mathematics University of Dhaka Dhaka1000 Bangladesh SR University Telangana State Warangal506371 India Department of Mathematics Faculty of Science Aswan University Aswan81528 Egypt Department of Mathematics Comilla University Cumilla3506 Bangladesh Department of Mathematics Bowen University Iwo Nigeria

This project covers the investigation of the boundary layer flow of a hybrid nanofluid past a biaxial stretching/shrinking sheet. The hybrid nanofluid consists of copper (Cu) and alumina (Al2O3) nanoparticles, which are diluted into water to form Cu-Al2O3- water hybrid nanofluid. The governing partial differential equations (PDEs) are derived from Navier-Stokes equations. The system of PDEs is reduced to a system of ordinary differential equations using an appropriate similarity transformation. MATLAB’s bvp4c function is used to numerically solve the resulting system of governing ordinary differential equations. The aim of this study is to gain a comprehensive understanding of the intricate behavior displayed by hybrid nanofluids on the stagnant directed flow of extended/shrunk flat surfaces, considering the effects of Brownian motion, thermophoresis, and various nanoparticles. The generated numerical results of flow profiles, skin friction coefficient, and Nusselt number have been presented graphically and discussed in the relevance of the governing parameters contributing to the flow. The outcomes reveal that the velocity components are reduced with increasing Al2O3- water nanofluid volume fraction. A monotonical increase in the parameters stretching/shrinking and suction/injection with a corresponding rise in both nanoparticles volume fraction propels heat gradient rate. An increase in the Schmidt numbers encourages a mass transfer field due to an enhanced boundary viscosity. The validation of numerical results is done with previously published results. Through our results, we have found that the performance of a hybrid nanofluid is more significant than other fluids. In addition, this study enhances the progress of theoretical comprehension by endeavoring to resolve the intricate interplay between fluid dynamics and thermal characteristics through the utilization of numerical approaches. © The Author(s) 2024.

关键词： Nanoparticles

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CONSTRAINED BI-LEVEL OPTIMIZATION: PROXIMAL LAGRANGIAN VALUE FUNCTION APPROACH AND HESSIAN-FREE ALGORITHM 12

CONSTRAINED BI-LEVEL OPTIMIZATION: PROXIMAL LAGRANGIAN VALUE...

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12th International Conference on Learning Representations, ICLR 2024

作者： Yao, Wei Yu, Chengming Zeng, Shangzhi Zhang, Jin National Center for Applied Mathematics Shenzhen SUSTech China Department of Mathematics SUSTech China Department of Mathematics and Statistics UVic Canada CETC Key Laboratory of Smart City Modeling Simulation and Intelligent Technology The Smart City Research Institute of CETC China

This paper presents a new approach and algorithm for solving a class of constrained Bi-Level Optimization (BLO) problems in which the lower-level problem involves constraints coupling both upper-level and lower-level variables. Such problems have recently gained significant attention due to their broad applicability in machine learning. However, conventional gradient-based methods unavoidably rely on computationally intensive calculations related to the Hessian matrix. To address this challenge, we devise a smooth proximal Lagrangian value function to handle the constrained lower-level problem. Utilizing this construct, we introduce a single-level reformulation for constrained BLOs that transforms the original BLO problem into an equivalent optimization problem with smooth constraints. Enabled by this reformulation, we develop a Hessian-free gradient-based algorithm-termed proximal Lagrangian Value function-based Hessian-free Bilevel Algorithm (LV-HBA)-that is straightforward to implement in a single loop manner. Consequently, LV-HBA is especially well-suited for machine learning applications. Furthermore, we offer non-asymptotic convergence analysis for LV-HBA, eliminating the need for traditional strong convexity assumptions for the lower-level problem while also being capable of accommodating non-singleton scenarios. Empirical results substantiate the algorithm's superior practical performance. © 2024 12th International Conference on Learning Representations, ICLR 2024. All rights reserved.

关键词： Machine learning

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Analyzing emotions in online classes: Unveiling insights through topic modeling, statistical analysis, and random walk techniques

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International Journal of Cognitive Computing in Engineering 2024年第1期5卷 221-236页

作者： Abdellaoui, Benyoussef Remaida, Ahmed Sabri, Zineb Abdellaoui, Mohammed El Hafidy, Abderrahim El Bouzekri El Idrissi, Younes Moumen, Aniss National School of Applied Sciences Engineering Sciences Laboratory Ibn Tofaïl University Kenitra Morocco Faculty of Sciences Laboratory of Computer Science Ibn Tofaïl University Kenitra Morocco LPHE-modeling and Simulation Faculty of Sciences Mohammed V University Rabat Morocco Software Project Management Research Team ENSIAS Mohammed V University Rabat Morocco

High dropout rates globally perpetuate educational disparities with various underlying causes. Despite numerous strategies to address this issue, more attention should be given to understanding and addressing student emotions during classes. This lack of focus adversely affects learner engagement and retention rates. While previous studies on online learning have primarily emphasized the effectiveness of technology, infrastructure, cognition, motivation, and economic benefits, there is still a gap in understanding the emotional aspects of distance learning. First, this study addresses this gap by employing thematic modeling and utilizing non-negative matrix factorization (NMF) for emotion recognition through students’ deep learning techniques and facial emotion recognition (FER). Second, statistical analysis of these findings further augments the depth of the study. Finally, the research proposes a mathematical model based on the random walk of emotional state transitions. The findings of this study underscore the importance of considering emotions in distance learning environments and their significant impact on student's academic performance and satisfaction. By acknowledging and addressing these emotional factors, educators can enhance learner engagement, promote positive emotions, mitigate negative emotions during online learning, and ultimately improve the effectiveness of online courses. © 2024 The Authors

关键词： Emotion Recognition

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Comparative Analysis of T-gate GaN HEMT with different passivation layers for RF Applications 3

Comparative Analysis of T-gate GaN HEMT with different passi...

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3rd International Conference on Communication, Control, and Intelligent Systems, CCIS 2024

作者： Shakya, Arzoo Pal, Praveen Kabra, Sneha University of Delhi Modeling and Simulation Research Laboratory Shaheed Rajguru College of Applied Sciences for Women New Delhi India Indian Institute of Technology Nanolab Department of Electrical Engineering Uttar Pradesh Kanpur India University of Delhi Shaheed Rajguru College of Applied Sciences for Women Department of Instrumentation New Delhi India

ISBN: (纸本)9798331528201

In this work, we investigate the impact of various passivation layers on electrical characteristics of T-gate GaN HEMT. Passivation schemes with single passivation layer of SiO2, Al2O3, HfO2, and stacked HfO2/SiO2 with and without air gap have been investigated. The air gap between the gate and the low-k passivation layer effectively reduces the gate capacitance, thereby enhancing the RF characteristics of the device. A 200 nm gate length and 100 μm width are used to simulate the device. The passivation layer of SiO2 with air gap, due to improved transconductance and gate capacitances exhibits a cut-off frequency of 39.22 GHz and a maximum oscillation frequency of 51.6 GHz. Results clearly shows that AlGaN/GaN HEMT having SiO2 with an air gap is most suitable for RF applications. © 2024 IEEE.

关键词： Gallium nitride

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Comparative Analysis of GaN HEMT on β-Ga2O3 and conventional substrates for RF Applications 12

Comparative Analysis of GaN HEMT on β-Ga2O3 and conventiona...

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12th International Conference on Internet of Everything, Microwave, Embedded, Communication and Networks, IEMECON 2024

作者： Shakya, Arzoo Pal, Praveen Kabra, Sneha Modeling and Simulation Research Laboratory Shaheed Rajguru College of Applied Sciences for Women University of Delhi New Delhi India Nanolab Department of Electrical Engineering Indian Institute of Technology Uttar Pradesh Kanpur India Department of Instrumentation Shaheed Rajguru College of applied Sciences for Women University of Delhi New Delhi India

ISBN: (纸本)9798350387315

This work presents performance investigation of the impact of different substrates on GaN-HEMTs, with an emphasis on important parameters including drain current, transconductance, and cut-off frequency. GaN-HEMT device with gate length of 200 nm and gate width of 100 μm was used to study the device performance using different substrates such as 6H-SiC, Al2O3, GaN, and β-Ga2O3. It has been observed that β-Ga2O3, shows excellent device performance with a maximum drain current of 1.21 A/mm, a peak transconductance of 262.46 mS/mm, and a cut-off frequency of 50.59 GHz. These findings demonstrate that β-Ga2O3 can be used as a suitable substrate for improving GaN-HEMT performance, especially for high frequency high power application. © 2024 IEEE.

关键词： III-V semiconductors

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Computer simulation based analysis of transient two-phase thermal evolutions during multiprobe cryosurgery of hepatic tissues embedded without or with blood vessels

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International Journal of Thermofluids 2024年 21卷

作者： Hossain, Sorowar Hossain, S. M. Chapal Ferdows, Mohammad Bangalee, Md. Zavid Iqbal Alam, Md. Shariful Department of Applied Mathematics University of Dhaka Dhaka1000 Bangladesh Research Group of Fluid Flow Modeling and Simulation Department of Applied Mathematics University of Dhaka Dhaka1000 Bangladesh Department of Mathematics Jagannath University Dhaka1100 Bangladesh

Cryosurgery is demarcated as cell annihilation by freezing temperature yielded through a cryogenic probe. Thermal distributions nearby the adjacent blood vessels can impede the iceball evolution and surgery success. Hence it is indispensable to predict the dynamic temperature and iceball propagations in biological tissues and its implications earlier through simulation methods. In this study, a transient two-phase flow and heat transfer model is presented to envisage the thermal extents inside and outside cryoprobes. The bioheat transfer model is adopted to inspect the temperature evolutions during multiprobe cryosurgery of hepatic tissues embedded without or with blood vessels. During computer simulation, a 3D geometry model is introduced as the living tissue vicinities embedded with two simplified hepatic arteries when multiple cryogenic probes are injected into the tissues with uniform insertion depth system. The tissues are pondered as non-ideal materials in which phase transition occurs over a temperature range, and the effects of blood perfusion and metabolic heat generation in the tissues are also considered. Computational analyses are then carried out to scrutiny the impact of the blood vessels on the temperature developments of tissues. The results show that when blood vessels are treated as a heat source during treatment, oscillatory thermal outlines are found along the anticipated pathways during multiprobe cryosurgery, and the relative maximum temperature increased upto ∼98 % at the midpoint of the route BB′ for the ablation time of 100 s. The irregular ice fronts are also obtained with the manifestation of blood vessels compared with no blood vessel case, and the iceball volume enclosed by the − 40°C isothermal front decreased significantly from 22.94 cm3 (without blood vessels) to 6.92 cm3 (with blood vessels) for the ablation time of 300 s. The simulation outcomes indicate that multiprobe cryosurgery is more effective to destroy the tumor tissue prope

关键词： Blood vessels

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Computation of heat transfer in magnetised Blasius flow of nano-fluids with suspended carbon nanotubes through a moving flat plate

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International Journal of Ambient Energy 2022年第1期43卷 7657-7665页

作者： Ferdows, M. Shamshuddin, M.D. Salawu, S.O. Reza, Motahar Research group of fluid flow modeling and simulation. Department of Applied Mathematics University of Dhaka Dhaka Bangladesh Telangana Warangal India Department of Physical Science Mathematics Programme College of Pure and Applied Sciences Landmark University Kwara State Omu-aran Nigeria Department of Mathematics GITAM School of Science GITAM Deemed to be University Hyderabad Campus Telangana Hyderabad India

This paper examines a two-dimensional steady, incompressible and laminar hydro-magnetic flow along with the transfer of heat above a plane plate that contains water and ethylene glycol-based nano-fluids with multi- and single-wall CNTs. The plate surface is subjected to variable wall temperatures. The transfer of heat has been contemplated in suspended CNTs above a plane plate. Navier–Stokes and the concept of the Prandtl boundary layer have been used to determine the governing equations of heat transfer and flow. Since the attained governing equations representing energy and flow are non-linear PDEs, they are altered into non-linear ODEs accompanied by analogous boundary conditions by applying several appropriate similarity transformations. Hence, the ‘bvp4c’ function is used to solve them numerically. Various graphs with physical interpretation demonstrate the consequence of determining terms on the characteristics of the flow. The plate velocity parameter and volume fraction have a positive effect. Temperatures are elevated markedly for most of the governing parameters. The rate of heat transfer and temperature exponent are enhanced by a magnetic field. SWCNTs give more substantial heat transfer than MWCNTs. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Nanoparticles

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Heat and Mass Transfer During MHD Flow of a Nanofluid Containing Gyrotactic Microorganisms on a Stretching/Shrinking Sheet

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Multiscale Science and Engineering 2022年第1期4卷 55-65页

作者： Ferdows, M. Misra, J. C. Research Group of Fluid Flow Modeling and Simulation Department of Applied Mathematics University of Dhaka Dhaka Bangladesh Centre for Theoretical Studies Indian Institute of Technology Kharagpur India

This paper deals with a study on the magnetohydrodynamic boundary layer flow and transfer of heat and mass of a viscous nanofluid comprising gyrotactic microorganisms. The flow is supposed to take place on a sheet, which stretches or shrinks asymmetrically in its own plane, where the line of symmetry of the stagnation motion and that of the stretching/shirking surface are in general not aligned. The governing non-linear partial differential equations and auxiliary conditions are transformed to a set of non-linear ODEs with the suitable boundary conditions by using similarity transformation. The resulting equations are solved numerically employing spectral relaxation method (SRM) through the use of MATLAB. We take some initial guesses, which satisfy the boundary condition for the iterative spectral relaxation technique. The influences of assorted parameters such as velocity ratio parameter α, source/sink parameter Q, Prandtl number Pr, magnetic field parameter M, Peclet number Pe, Lewis number Le, Bioconvection Lewis number Lb, Brownian motion parameter Nb, thermophoresis parameter Nt, Eckert number Ec, local Eckert numbers (Ecx and Ecy) and bioconvection constant σ are investigated. Transfer of mass and heat and the impact of microorganisms present in the fluid are explored through graphs and tables and the results are discussed in details. Variation in the skin-friction, heat transfer rate and the density number of the motile microorganism is also investigated. Residual error analysis is also performed for establishing the convergence rate against iteration. The study reveals that the velocity enhances, but the temperature reduces with rise in the strength of the magnetic field, while the thickness of the motile microorganisms is reduced as the Peclet number increases.

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Flow and heat transfer of a nanofluid through a porous medium due to stretching/shrinking sheet with suction,magnetic field and thermal radiation

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applied Mathematics(A Journal of Chinese Universities) 2023年第3期38卷 373-391页

作者： Ubaidullah Yashkun Khairy Zaimi Suliadi Firdaus Sufahani Mohamed REid Mohammad Ferdows Centre of Excellence for Social Innovation and Sustainability Institute of EngineeringUniversiti Malaysia PerlisPauh Putra Campus02600ArauPerlisMalaysia Department of Mathematics Sukkur IBA UniversityAirport RoadSukkur65200SindhPakistan Department of Mathematics and Statistics Faculty of Applied Sciences and TechnologyUniversiti Tun Hussein Onn MalaysiaJohorMalaysia Department of Mathematics Faculty of ScienceNew Valley UniversityAl-Wadi Al-GadidAl-Kharga 72511Egypt Mathematics Department Faculty of ScienceNorthern Border UniversityArar 1321Saudi Arabia Research Group of Fluid Flow Modeling and Simulation Department of Applied MathematicsUniversity of DhakaDhaka-1000Bangladesh

This study investigates the suction and magnetic field effects on the two-dimensional nanofluid flow through a stretching/shrinking sheet at the stagnation point in the porous medium with thermal *** governing partial differential equations(PDEs)are converted into ordinary differential equations(ODEs)using the similarity *** resulting ODEs are then solved numerically by using the bvp4c solver in MATLAB *** was found that dual solutions exist for the shrinking parameter values up to a certain *** numerical results obtained are compared,and the comparison showed a good agreement with the existing results in the *** governing parameters’effect on the velocity,temperature and nanoparticle fraction fields as well as the skin friction coefficient,the local Nusselt number and the Sherwood number are represented graphically and *** variation of the velocity,temperature and concentration increase with the increase in the suction and magnetic field *** seems that the thermal radiation effect has increased the local Sherwood number while the local Nusselt number is reduced with it.

关键词： stagnation point flow nanofluid porous medium suction magnetohydrodynamic thermal radiation

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