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Investigation of the mesmeric effect of substituents in DSSC based on thiophene and oxadiazole. Structural and optoelectronic study using the DFT approach

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Interactions 2025年第1期246卷 1-15页

作者： Agda, Fatima Nebbach, Diae Louazri, Latifa Ninis, Ouafae Merimi, Imane Ajana, Mohammed Aziz Bouachrine, Mohammed Laboratory Molecular and Computational Chemistry: Design Synthesis and Reactivity. Department of Chemistry Faculty of Science Moulay Ismail University Meknes Morocco Regional Center for Education and Training Professions Meknes Morocco Energy Materials and Computing Physics Research Group ENS Abdelmalek Essaadi University Tetouan Morocco Advanced Materials and Process Engineering Laboratory Faculty of Science Ibn Tofail University Kenitra Morocco National School of Architecture National Road N2 Compus de Savoir Technolopole Oujda Oujda60000 Morocco Faculty of Sciences Mohammed First University Oujda Morocco

In this work, we have developed a range of organic Donor- π -Acceptor;we are changing the π-spacers by adding novel substitutions (F, CH3, and CN) to the base molecule D-TTOxTT-A for dye-sensitized solar cells (DSSCs). Our aim is to improve the photovoltaic performance of these engineered organic dyes. We use the B3LYP (d,p) and TD/CAM-B3LYP (d,p) to study the impact of different types of the introduction of the substitution in the spacer, on the sensitizer characteristics, with the aim of highlighting the links between structure and property. Based on these results, it is possible to use these dyes as promising sensitizers for DSSCs. In addition, M4 could be an ideal compound for high throughput DSSC due to its planar geometry, low energy gap (1.73eV), higher absorption wavelength (449.3nm), longer lifetime (2.366 ns), lower ΔGreg (-0.64 eV), large hardness (-0.869 eV) and reasonable energy reorganization (0.488eV). © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.

关键词： Thiophene

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Prediction and validation of aeroelastic limit cycle oscillations using harmonic balance methods and Koopman operator

Research Square

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Research Square 2025年

作者： McGurk, Michael Yuan, Jie Aerospace Centre of Excellence Department of Mechanical and Aerospace Engineering University of Strathclyde GlasgowG1 1XQ United Kingdom Computational Engineering Design Group Department of Aeronautics and Astronautics Engineering University of Southampton SouthamptonSO17 1BJ United Kingdom

The presence of nonlinearities within aerospace systems often triggers self-sustaining oscillations known as Limit Cycle Oscillations (LCO), demanding costly analysis for identification, notably through the resource-intensive generation of bifurcation diagrams. Consequently, the expense incurred tends to sideline nonlinear analysis in initial design phases, constraining design possibilities and impeding data-driven methods for nonlinear aeroelastic analysis reliant on efficient data collection, which has garnered attention in the aerospace sector. This work proposes a computationally efficient numerical framework for calculating LCO amplitudes and determining stability in nonlinear aeroelastic systems. The framework consists of using Harmonic Balance Methods (HBM) combined with the Hill method for the stability analysis. To avoid the sorting problem, the Koopman operator-based data-driven method is implemented. The methodology is applied to numerical test cases, encompassing both smooth and nonsmooth nonlinearities, and validated against outcomes from MATCONT and COCO. Subsequently, an experimental validation of the framework is conducted, comparing its outcomes to existing LCO experimental data acquired through control-based continuation experiments. © 2025, CC BY.

关键词： Bifurcation (mathematics)

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computational efficient process simulation of geometrically complex parts in metal additive manufacturing

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International Journal of Heat and Mass Transfer 2025年 248卷

作者： Yang, Y. Ji, Y. Möller, M. Ayas, C. Computational Design and Mechanics Group Department of Precision and Microsystems Engineering Faculty of Mechanical Engineering Mekelweg 2 Delft2628 CD Netherlands Delft Institute of Applied Mathematics Delft University of Technology Mekelweg 4 Delft2628 CD Netherlands

Part-scale thermal process simulations play an important role in improving the part quality of the Laser Powder Bed Fusion (LPBF) process. The semi-analytical simulation method relies on the superposition of analytical fields to represent laser-induced heat sources in a semi-infinite space and a complementary temperature field to enforce boundary conditions. So far, boundary conditions have been imposed by analytical image fields for straight boundaries and numerically for non-straight boundaries. The latter requires considerable refinement on the spatial discretization, at least near the boundaries, and compromises the computational efficiency of the simulations. In this paper, we derive a closed-form solution for the image fields that can accurately enforce the boundary conditions for non-straight boundaries. A geometrically complex part boundary is represented by B-splines, and with the aid of an offset method and reparameterization, the positions of the image sources are determined. The image field's closed-form expression is then found using the boundary's local curvature calculated from the local tangent lines. Numerical examples on different levels of complexity revealed that the net heat lost along an adiabatic boundary vanishes when the novel image source solutions are used, and the thermal evolution of complex parts can be accurately predicted with high computational efficiency. Simulations involving multiple lasers can also be performed with no extra computational cost. © 2025 The Authors

关键词： Photointerpretation

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The dynamics of negative correlation learning

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Journal of VLSI Signal Processing Systems for Signal, Image, and Video Technology 2007年第2期49卷 251-263页

作者： Eastwood, Mark Gabrys, Bogdan Computational Intelligence Research Group School of Design Engineering and Computing Bournemouth University Bournemouth United Kingdom

In this paper we combine two points made in two previous papers on negative correlation learning (NC) by different authors, which have theoretical implications for the optimal setting of λ, a parameter of the method whose correct choice is critical for stability and good performance. An expression for the optimal λ is derived whose value λdepends only on the number of classifiers in the ensemble. This result arises from the form of the ambiguity decomposition of the ensemble error, and the close links between this and the error function used in NC. By analyzing the dynamics of the outputs we find dramatically different behavior for λ∈∈λ, providing further motivation for our choice of λ and theoretical explanations for some empirical observations in other papers on NC. These results will be illustrated using well known synthetic and medical datasets. © 2007 Springer Science+Business Media, LLC.

关键词： Learning algorithms

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Conceptual design of UAV airframes using a generic geometry service

Conceptual design of UAV airframes using a generic geometry ...

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InfoTech at Aerospace: Advancing Contemporary Aerospace Technologies and Their Integration

作者： Sóbester, András Keane, Andy J. Scanlan, James Bressloff, Neil W. University of Southampton Southampton Hampshire SO17 1BJ United Kingdom Computational Engineering and Design Group United Kingdom AIAA United States Department of Computational Engineering Computational Engineering and Design Group United Kingdom Department of Engineering Design Computational Engineering and Design Group United Kingdom

ISBN: (纸本)1563477394

With the increased freedom in layout selection possible when designing an Unmanned Air Vehicle (UAV) concept (compared, for example, to the relatively constrained and mature world of commercial airliner design), comes the significant challenge of building a geometry engine that will provide the variety of airframe models demanded by the highly global nature of the design search. In order to enable multidisciplinary trade-off studies, both an external surface and an internal structure are required - we use a single, generic model to supply these, in the form of a parametric geometry residing in a commercial CAD tool. In addition to discussing the challenges of offering a truly flexible geometry service, we also delve into the UAV-specific issues of the initial sizing of the model. A wealth of statistical data provides one of the traditional handholds for this step in manned aircraft conceptual design - we discuss the applicability of such statistical approaches to their unmanned counterparts.

关键词： Unmanned vehicles

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Spring back of infinite honeycomb sheets beyond plastic deformation

Spring back of infinite honeycomb sheets beyond plastic defo...

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Advanced Materials for Demanding Applications

作者： Bonfanti, A. Bhaskar, A. Computational Engineering and Design Group Faculty of Engineering and the Environment University of Southampton United Kingdom

Cellular structures are promising for applications where high stiffness and strength are required with the minimal use of material. They are often used in applications where the plastic deformation plays an important role, such as those involving crashworthiness, energy absorption, and stents. The elastic analysis of a honeycomb sheet has been carried out in the past [1]. The present analysis extends this classical work in the elasto-plastic regime. Recoil analysis due to elastic recovery is absent from the published literature. This work aims to develop an analytical model to calculate the spring back for a simplified case, that of an infinite honeycomb sheet. An elastic-perfectly plastic material model is assumed. The recoil for a clamped beam with a load and moment applied at the free edge is analytically calculated first. This is carried out by relating the stress distribution of the cross section to the final deformed shape. The part corresponding to the elastic contribution is subsequently subtracted in order to obtain the final configuration after the external load is removed. This simple elasto-plastic analysis is then incorporated into the analysis of an infinite sheet made of uniform hexagonal cells. The translational symmetry of the lattice is exploited along with the analysis of a beam under tip loading through to plastic stage and recoil. The final shape of the struts upon the removal of the remote stress is completely determined by the plastic deformation which cannot be recovered. The expression for the beam thus obtained is then used to build an analytical model for an infinite honeycomb sheet loaded in both directions.

关键词： Analytical models

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Multidisciplinary design optimization of UAV airframes

Multidisciplinary design optimization of UAV airframes

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47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

作者： Sábester, András Keane, Andy J. University of Southampton Southampton Hampshire SO17 1BJ United Kingdom Computational Engineering and Design Group United Kingdom AIAA United States Department of Computational Engineering Computational Engineering and Design Group United Kingdom

ISBN: (纸本)1563478080

If one considers the problem of converting an aircraft mission profile into an airframe design from an optimization theory perspective, it becomes obvious that this search problem comes with all the trimmings. The design space is large and multidimensional, there are multiple and often highly multimodal objectives and constraints, these depending not only on the design variables, but often on each other as well. Multidisciplinary design Optimization studies can be conducted at different levels of detail, depending on the chosen tradeoff between the size of the design space and the fidelity of the analysis. In this paper we discuss some of the challenges arising at the conceptual level, where simple, but versatile models and low cost analysis tools are used to guide the designer through the first, fundamental decisions of the design process. At the center of our proposed design workftow lies a parametric geometry, residing in an off-the-shelf Computer-Aided design (CAD) tool - this provides the models required by the multidisciplinary analyses. We also touch on some of the issues specific to the design of our chosen class of aircraft - Unmanned Air Vehicles (UAVs). To summarize: a CAD-based UAV conceptual design framework is proposed and demonstrated.

关键词： Unmanned aerial vehicles (UAV)

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Multi-variable geometry repair and optimization of passive vibration isolators

Multi-variable geometry repair and optimization of passive v...

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48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

作者： Forrester, Alexander I. J. Keane, Andy J. University of Southampton Southampton Hampshire SO17 1BJ United Kingdom AIAA United States Computational Engineering and Design Group United Kingdom Department of Computational Engineering Computational Engineering and Design Group United Kingdom

ISBN: (纸本)1563478927

A range of techniques are considered for the search of a high dimensional design landscape with extensive, unknown and disjointed regions of infeasibility. We present the use of a hybrid genetic-algorithm / gradient-descent search of the objective function / feasibility problem. The genetic algorithm is used to optimize the vibration isolation of a novel passive structure concept, while the gradient descent method is used to repair infeasible geometries. For a more complicated structure the gradient search fails to find feasible geometries and we resort to a non-dominated sorting multi-objective genetic algorithm which searches the vibration isolation and geometry feasibility simultaneously. Although the complicated geometry is more difficult to optimize, there is potential for significant improvements in vibration isolation.

关键词： Microwave isolators

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Reinforcement Learning, Social Value Orientation, and Decision Making: computational Models and Empirical Validation 44

Reinforcement Learning, Social Value Orientation, and Decisi...

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44th Annual Meeting of the Cognitive Science Society: Cognitive Diversity, CogSci 2022

作者： Duggins, Peter Eliasmith, Chris Stewart, Terrence C. Computational Neuroscience Research Group Department of Systems Design Engineering University of Waterloo Canada

Social environments often impose tradeoffs between pursuing personal goals and maintaining a favorable reputation. We studied how individuals navigate these tradeoffs using Reinforcement Learning (RL), paying particular attention to the role of social value orientation (SVO). We had human participants play an interated Trust Game against various software opponents and analyzed the behaviors. We then incorporated RL into two cognitive models, trained these RL agents against the same software opponents, and performed similar analyses. Our results show that the RL agents reproduce many interesting features in the human data, such as the dynamics of convergence during learning and the tendency to defect once reciprocation becomes impossible. We also endowed some of our agents with SVO by incorporating terms for altruism and inequality aversion into their reward functions. These prosocial agents differed from proself agents in ways that resembled the differences between prosocial and proself participants. This suggests that RL is a useful framework for understanding how people use feedback to make social decisions. © 2022 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY)

关键词： Reinforcement learning

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Knowledge based system for cost modelling

Knowledge based system for cost modelling

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7th AIAA Aviation Technology, Integration, and Operations Conference

作者： Tammineni, S.V. Scanlan, J.P. Reed, P.A.S. School of Engineering Science Southampton Hampshire-SO17 3RE United Kingdom Computational Engineering and Design Group School of Engineering Science Department of Design Computational Engineering and Design Group School of Engineering Science Department of Structural Materials Engineering Materials and Surface Engineering School of Engineering Science

ISBN: (纸本)1563479087

This paper presents the application of knowledge based system environment for cost modelling. Unique to this environment is an innovative knowledge representation technique known as tree objects that helps in modelling a unified product model that has various levels of model abstraction. There will be a detailed presentation about the advantages of tree object properties in cost modelling. The environment will support a generative cost estimation based on manufacturing features by providing access to knowledge base libraries of material, work center, and processes tree objects. The populations and structure of these libraries elements that form the building blocks is discussed. This modelling approach will enable cost optimization at various levels of product abstraction in conceptual design stage. A case study demonstrating the application of this approach for building a cost model for a Rolls Royce tile styled combustor liner assembly has been presented.

关键词： Knowledge based systems

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