Article
Chemistry, Physical
Takashi Tsuchimochi, Yoohee Ryo, Seiichiro L. Ten-no, Kazuki Sasasako
Summary: Quantum imaginary time evolution (QITE) is a hybrid algorithm that can guarantee reaching the lowest state of a system. This study improves upon QITE, specifically for molecular applications. The derivation of the QITE equation is analyzed step-by-step, and a theoretically well-founded modification is proposed. The results demonstrate the effectiveness of the derived equation, providing a better approximation for imaginary time propagation. Additionally, accurate estimation of the norm of an imaginary-time-evolved state is discussed and applied in excited state calculations using the quantum Lanczos algorithm. The folded-spectrum QITE scheme is also introduced as an extension for general excited-state simulations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Takashi Tsuchimochi, Yoohee Ryo, Seiichiro L. Ten-no, Kazuki Sasasako
Summary: In this study, several improvements are made to the Quantum Imaginary Time Evolution (QITE) algorithm, with a focus on molecular applications. By analyzing the derivation of the QITE equation and suggesting a theoretically grounded modification, our results demonstrate the soundness of the derived equation and its ability to better approximate imaginary time propagation. We also discuss accurately estimating the norm of an imaginary-time-evolved state and its application to excited state calculations. Additionally, the folded-spectrum QITE scheme is proposed as a straightforward extension for general excited-state simulations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Computer Science, Software Engineering
Ryusuke Sugimoto, Terry Chen, Yiti Jiang, Christopher Batty, Toshiya Hachisuka
Summary: We introduce the walk-on-boundary (WoB) method, a grid-free Monte Carlo solver, for solving certain second order partial differential equations in computer graphics. Compared to the popular walk-on-spheres (WoS) method, WoB has additional advantages as it naturally supports various boundary conditions and is mathematically similar to light transport simulation in rendering. We demonstrate the advantages of WoB over WoS through numerical results, showing that WoB can estimate solutions precisely on the boundary without suffering from intrinsic bias.
ACM TRANSACTIONS ON GRAPHICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Basudeb Dutta, Faruk Ahmed, Mohammad Hedayetullah Mir
Summary: The design and synthesis of electrically conductive coordination polymers (CPs) have attracted special interest due to their applications in various emerging technologies. CPs, with their structural flexibility and adjustable energy levels, show promise in providing improved charge transport pathways. The use of visible light as an external stimulus further motivates the development of optoelectronic devices. This study provides an overview of recent advances in photo-responsive CPs and their potential applications in optoelectronic devices.
DALTON TRANSACTIONS
(2023)
Article
Computer Science, Software Engineering
Rohan Sawhney, Bailey Miller, Ioannis Gkioulekas, Keenan Crane
Summary: Grid-free Monte Carlo methods based on the walk on spheres (WoS) algorithm can solve fundamental partial differential equations without discretizing the problem domain. We introduce the walk on stars (WoSt) algorithm, which can solve linear elliptic PDEs with arbitrary mixed Neumann and Dirichlet boundary conditions.
ACM TRANSACTIONS ON GRAPHICS
(2023)
Article
Computer Science, Software Engineering
Bailey Miller, Rohan Sawhney, Keenan Crane, Ioannis Gkioulekas
Summary: This paper proposes a fast caching strategy for solving elliptic partial differential equations by estimating solution values and derivatives at randomly sampled points along the boundary, and then using these cached values to evaluate the solution at interior points via a boundary integral formulation. Unlike classic methods, this caching scheme introduces zero statistical bias and does not require a dense global solve. It also handles imperfect geometry and detailed boundary/source terms without repairing or resampling the boundary representation. The approach is validated using test problems from visual and geometric computing.
ACM TRANSACTIONS ON GRAPHICS
(2023)
Article
Chemistry, Multidisciplinary
Leon Otis, Eric Neuscamman
Summary: We discuss recent progress in excited-state-specific quantum chemistry and quantum Monte Carlo and show how combining methods from these fields can predict excited states accurately. Important advances in both fields include improved optimization methods, handling of complicated wave function forms, and balancing the quality of wave functions for ground and excited states. Demonstrations using a combination of specific quantum chemistry and variational Monte Carlo show that this approach is more reliable and accurate than other high-level methods and can provide clarity in cases where existing methods do not agree.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Article
Polymer Science
Zhiyong Yang, Linli He, Linxi Zhang
Summary: The conformations of a semiflexible polyelectrolyte chain with neutralizing charged counterions confined in a cylinder were investigated through off-lattice Monte Carlo simulations. The study found that at suitable parameter combinations, perfect helical structures can be observed, with larger cylindrical radius leading to a smaller range of the helix phase region.
Article
Physics, Multidisciplinary
Sergio Contreras, Alejandro Gil-Villegas
Summary: Computer simulations and theoretical results of N Quantum Hard Spheres (QHS) particles show that analytical results can be provided for extreme and maximum confinement based on an extension of the Helmholtz free energies for classical systems.
Article
Multidisciplinary Sciences
Slawomir Ertman, Kamil Orzechowski, Katarzyna Rutkowska, Oliwia Kolodynska, Julia Rozycka, Adam Ignaciuk, Natalia Wasilewska, Tomasz Osuch, Tomasz R. Wolinski
Summary: Different methods for creating optical waveguides with liquid-crystal cores, including reversible photoalignment and microstructure methods, were investigated. The period of the patterned alignment was controlled using selective illumination and microelectrodes. Experimental studies and numerical simulations were performed to understand the waveguiding phenomenon. Waveguiding in blue phase liquid crystal with tunable first-order bandgap was achieved.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Nicholas Fritz, Daniel Gulick, Mark Bailly, Jennifer M. Blain Christen
Summary: Optogenetics offers a less-invasive alternative to electrical stimulation for interfacing with the nervous system, but faces challenges of light scattering and absorption in tissues. The use of multiple focused light emissions may help overcome these limitations but requires careful design considerations for effective stimulation of nerves.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Yuefei Zhang, Jiemin Wei, Tianyun Liu, Zheng Zhong, Zijiang Luo, Wenjun Xiao, Bing Lv, Xun Zhou, Xuefei Liu
Summary: The graphene-based Van der Waals heterostructures demonstrate great potential for the next generation of photoelectronic nanodevices. ZnSe is found to be a direct semiconductor with high electron mobility and the potential to achieve Schottky to Ohmic contact transformation. Furthermore, under light irradiation, hydrogen and oxygen evolution reactions can occur spontaneously in both acidic and alkaline media. Introducing 3d transition metal atoms significantly reduces the overpotential for the HER process of ZnSe monolayer.
APPLIED SURFACE SCIENCE
(2022)
Article
Mathematics, Interdisciplinary Applications
D. P. Mahapatra, S. Triambak
Summary: The study demonstrates that using 2D random-walk Monte Carlo calculations can better predict the growth trajectory and multiple wave structures of infection cases during the COVID-19 pandemic to plan mitigation strategies effectively.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Physics, Fluids & Plasmas
E. J. Janse van Rensburg, E. Orlandini
Summary: The study examines the phase diagrams of two confined and dense two-dimensional ring polymer models numerically, finding that the phase diagrams are a function of the placement of the ring polymers and include multicritical points. Numerical estimates of critical exponents associated with phase boundaries and multicritical points were obtained.
Article
Multidisciplinary Sciences
Guangdong Chen, Hanwen Pei, Xuefei Zhang, Wei Shi, Mingjie Liu, Charl F. J. Faul, Bai Yang, Yan Zhao, Kun Liu, Zhongyuan Lu, Zhihong Nie, Yang Yang
Summary: This study demonstrates that achiral dumbbell-shaped colloids can assemble into various liquid crystal phases, including blue phase III. Phase diagrams show that the existence and stability of liquid crystal phases depend on the geometrical parameters of colloids. This work opens a new route for the design and construction of blue phases in photonic applications.
NATURE COMMUNICATIONS
(2022)
Article
Energy & Fuels
Mohamed Lotfi, Tiago Almeida, Mohammad S. Javadi, Gerardo J. Osorio, Claudio Monteiro, Joao P. S. Catalao
Summary: This study proposes and models the coordination between home energy management systems (HEMSs) and EV parking lot management systems (PLEMS), achieving optimal energy management through partially sharing individual EV schedules and without sharing private information. The results show that this coordination framework is both technically and economically beneficial for power grids and EV owners.
Article
Thermodynamics
Mohammad Sadegh Javadi, Ali Esmaeel Nezhad, Ahmad Rezaee Jordehi, Matthew Gough, Sergio F. Santos, Joao P. S. Catalao
Summary: This study proposes a fully decentralized model for electricity trading using a P2P trading framework to achieve the least-cost operation of industrial, commercial, and residential energy hubs. By employing the ADMM method to address decentralized power flow, ensuring minimal data exchange, and addressing data privacy concerns, the study effectively demonstrates the potential of P2P transactive energy trading between peers.
Article
Automation & Control Systems
Matthew B. Gough, Sergio F. Santos, Tarek AlSkaif, Mohammad S. Javadi, Rui Castro, Joao P. S. Catalao
Summary: This article develops an innovative algorithm that complies with differential privacy to protect data from smart meters, and thoroughly investigates its impact on the distribution grid from both consumer and power systems perspectives. The results show that the approach effectively preserves privacy without significant cost or loss increases for the energy retailer.
IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS
(2022)
Article
Engineering, Multidisciplinary
Meisam Mahdavi, Mohammad S. Javadi, Fei Wang, Joao P. S. Catalao
Summary: This article investigates the impact of load patterns on energy loss minimization in distribution system reconfiguration and evaluates three distribution systems using a classic optimization tool.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Engineering, Multidisciplinary
Matthew Gough, Sergio F. Santos, Mohamed Lotfi, Mohammad Sadegh Javadi, Gerardo J. Osorio, Paul Ashraf, Rui Castro, Joao P. S. Catalao
Summary: This article develops a technical Virtual Power Plant (TVPP) operational model to optimize the scheduling of diverse Distributed Energy Resources (DERs), considering the constraints of the power grid management. The results show that electric vehicles and solar photovoltaic units provide the largest benefits to the TVPP, and the operation of the TVPP improves financial metrics, increases consumer engagement, and enhances technical operational metrics.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Engineering, Multidisciplinary
Matthew Gough, Sergio F. Santos, Artur Almeida, Mohamed Lotfi, Mohammad S. Javadi, Desta Z. Fitiwi, Gerardo J. Osorio, Rui Castro, Joao P. S. Catalao
Summary: This article explores the disruptive potential of blockchain technology in energy trading markets and presents the application of blockchain-based smart contracts in distributed energy resource scheduling. The model complies with the new regulations in Portugal, resulting in decreased energy costs for consumers and increased locally generated electricity.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Alireza Bagheri, Mehdi Allahbakhshi, Mohammad Mehdi Arefi, Nassim Najafi, Mohammad Sadegh Javadi
Summary: This paper presents an online thermal modeling method based on the Unscented Kalman filter (UKF) for predicting the top-oil temperature (TOT) of transformers. The method is proven to be accurate and applicable through the comparison of actual and simulated data. This method has important implications for load management and the estimation of transformer insulation life.
IET ELECTRIC POWER APPLICATIONS
(2022)
Article
Engineering, Mechanical
Mohammad Vahid Ehteshamfar, Mohammad Sadegh Javadi, Hamed Adibi
Summary: This study investigates the influence of lapping parameters on the surface roughness, material removal rate, and flexural strength of FDM manufactured ABS parts. The results demonstrate that increasing lapping time improves the surface roughness, while optimizing angular velocity and weight is necessary. Additionally, lapping significantly enhances the surface roughness of ABS samples and transforms the anisotropic behavior of additively manufactured parts to isotropic behavior without reducing the flexural strength. This study provides a new approach to improve the surface quality of FDM parts.
RAPID PROTOTYPING JOURNAL
(2022)
Article
Thermodynamics
S. A. Mansouri, A. Ahmarinejad, E. Nematbakhsh, M. S. Javadi, A. Esmaeel Nezhad, J. P. S. Catalao
Summary: This paper presents a new framework for scheduling microgrids and distribution feeder reconfiguration, considering uncertainties from load demand, market price, and renewable power generation. The framework consists of a two-stage model, where the self-scheduling of microgrids is optimized in the first stage and the optimal configuration of the system is determined by the distribution system operator in the second stage. The results show that the deviation from optimal microgrid scheduling is significantly reduced when the system is reconfigured by the operator.
Article
Energy & Fuels
Rahmat Aazami, Saman Esmaeilbeigi, Majid Valizadeh, Mohammad S. Javadi
Summary: This paper discusses a hybrid scheme of adaptive and multi-agent protection for micro-grids. The proposed scheme provides safety protection at multiple layers and levels and utilizes the equipment in the micro-grid for calculations and simulations. The results demonstrate the good performance of the scheme.
SUSTAINABLE ENERGY GRIDS & NETWORKS
(2022)
Article
Engineering, Electrical & Electronic
Mohamed Lotfi, Gerardo J. Osorio, Mohammad S. Javadi, Mohamed S. El Moursi, Claudio Monteiro, Joao P. S. Catalao
Summary: Traditional power grids use probabilistic methods to handle load uncertainties, but modern smart grids require fully decentralized optimal operation techniques. This study proposes a machine learning algorithm that predicts optimal control actions using only local historical data, and enhances cooperative information exchange through a new concept called s-index activation codes. The algorithm is shown to be highly accurate and computationally efficient, with great potential for fully decentralized operation of smart grids.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2022)
Article
Engineering, Multidisciplinary
Juan M. Home-Ortiz, Ozy D. Melgar-Dominguez, Mohammad S. Javadi, Jose Roberto Sanches Mantovani, Joao P. S. Catalao
Summary: This article presents a restoration approach that improves the resilience of electric distribution systems by combining dynamic network reconfiguration, islanding operation of distributed generation units, and the prepositioning and displacement of emergency generation units. The approach also considers the use of demand response programs to enhance recoverability. The objective is to separate the in-service and out-of-service parts of the system while maintaining grid radiality.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Engineering, Electrical & Electronic
S. A. Mansouri, A. Ahmarinejad, F. Sheidaei, M. S. Javadi, A. Rezaee Jordehi, A. Esmaeel Nezhad, J. P. S. Catalao
Summary: This paper presents a two-stage stochastic model for the integrated design and operation of an energy hub system with electrical and thermal energy storage systems. Uncertainties are addressed through the incorporation of demand response and integrated demand response programs, and the problem is solved using real-coded genetic algorithm and binary-coded genetic algorithm. The simulation results show that considering uncertainties leads to increased investment cost, while implementing shiftable demand response program can reduce operating cost.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2022)
Article
Engineering, Electrical & Electronic
Darwin A. Quijano, Morteza Vahid-Ghavidel, Mohammad Sadegh Javadi, Antonio Padilha-Feltrin, Joao P. S. Catalao
Summary: Electric springs (ESs) have been proven effective for integrating renewable generation into power systems. This paper proposes a price-based strategy to coordinate the operation of multiple ESs in microgrids. Smart loads consisting of ESs connected to electric water heaters are modeled as rational agents that locally optimize their own objectives by adjusting their consumption schedules in response to price/control signals. Case studies show the effectiveness of the proposed strategy to economically benefit both the microgrid and smart loads when scheduling their operation.
IEEE TRANSACTIONS ON SMART GRID
(2023)
Article
Computer Science, Information Systems
Cleberton Reiz, Tayenne Dias de Lima, Jonatas Boas Leite, Mohammad Sadegh Javadi, Clara Sofia Gouveia
Summary: This study proposes a multi-objective optimization approach for sizing and allocating protection and control devices in distribution networks with microgrids supplied by renewable energy sources. The non-dominated sorting genetic algorithm is applied to solve the allocation problem, and compromise programming is performed to achieve the best solution. The results demonstrate interesting setups for the protection system and the feasibility of islanding operation.
