Article
Acoustics
Yanfeng Lang, Zhibo Yang, Xuefeng Chen
Summary: Amplitude and phase characteristics are widely used in Lamb wave imaging, but they are dependent on the baseline and affected by artifacts. Instantaneous frequency, although often neglected, is also an important source of damage information. A dispersive instantaneous frequency imaging algorithm is proposed to suppress the undesired mode and eliminate baseline dependence.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Automation & Control Systems
Javier A. Torres Bustos, Marcos E. Orchard, Miguel Torres-Torriti, Fernando Auat Cheein
Summary: Several countries are leading the effort of replacing internal combustion engines (ICE) in vehicles with electric ones in order to reduce dependence on oil and carbon emissions. However, the range of electric vehicles (EVs) is still lower compared to ICE vehicles, depending on the energy stored and its utilization rate. In this study, the authors propose a method to estimate the average power consumption of EVs using only localization information, achieving high accuracy without the need for extra sensors.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Patricio Salmeron, Juan. L. L. Flores-Garrido, Juan. A. A. Gomez-Galan
Summary: This paper presents a new approach for instantaneous reactive power analysis using geometric algebra (GA). Previous formulations of the instantaneous reactive power theory (IRPT) were developed for three-phase systems, where instantaneous power and reactive power variables were handled independently. With GA, a global treatment is possible by defining an instantaneous power multivector that includes all power variables within the same multidimensional entity. From this multivector, the instantaneous power current and the instantaneous reactive current can be determined. The advantage of this mathematical framework is the ability to analyze multi-phase systems without limitations. The proposed methodology is demonstrated through practical cases of five-phase and three-phase systems.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Analytical
Giovanni Nobile, Mario Cacciato, Ester Vasta
Summary: This paper presents a simple but effective way to calculate electric power, overcoming the need for direct measurement of phase shift and frequency. It calculates active power by utilizing the difference between the peak values of instantaneous power and apparent power, and evaluates reactive power and power factor using the same quantities.
Article
Acoustics
Jose M. Carcione, Stefano Picotti, Jing Ba
Summary: This study investigates the attenuation mechanism of thermoelastic waves, proposing a new time-domain algorithm for wave propagation based on fractional derivatives and the Cole-Cole equation. The algorithm is validated with the Savage theory and compared to analytical solutions, showing the complexity of wave propagation in different media.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Geosciences, Multidisciplinary
Qianyun Xu, Meng Zhou, Wenqing Ma, Jiansen He, Shiyong Huang, Zhihong Zhong, Ye Pang, Xiaohua Deng
Summary: This paper investigates the electron acceleration mechanism in strong turbulence in the Earth's magnetosheath based on novel observations. The study finds that electrons are magnetized in turbulent fields for the majority of the time and primarily accelerated by the parallel electric field within coherent structures. The acceleration rate increases as the spatial scale reduces, with the most intense acceleration occurring over about one ion inertial length.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Chemistry, Physical
Lucas Huber, Sebastian F. Maehrlein, Feifan Wang, Yufeng Liu, X. -Y. Zhu
Summary: The ultrafast optical Kerr effect is commonly used to investigate structural dynamics and interactions of materials, with non-degenerate mixing schemes allowing for more accurate detection. Two-color experiments can reveal sources of temporal dynamics in the OKE signal, showing how birefringence in crystalline solids can entirely change the character of the signal.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Xiaoyu Lang, Tao Yang, Zhen Huang, Zhenyu Wang, Serhiy Bozhko, Patrick Wheeler
Summary: This article presents an instantaneous power control technique for regulating the power flow of a back-to-back converter in an advanced power generation center for more-electric aircraft applications. Compared with the previously proposed method, the IPC method allows independent control of active and reactive power transfer, improves dynamic response in power control, and eliminates tedious tuning of control parameters.
IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION
(2022)
Article
Acoustics
Georg Maierhofer, N. Peake
Summary: The study examines the power balance of acoustic wave scattering by a cascade of flat blades in uniform subsonic mean flow, showing how it leads to an exchange of energy. It demonstrates that depending on certain parameters, vortex sheets can either absorb or generate acoustic energy, potentially resulting in a net increase in outgoing sound power over the incident sound power.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Chemistry, Physical
Hongchun Luo, Guangqin Gu, Wanyu Shang, Wenhe Zhang, Peng Cui, Bao Zhang, Junmeng Guo, Mingli Zheng, Gang Cheng, Zuliang Du
Summary: An interactive-excited strategy combining a waterdrop triboelectric nanogenerator (WD-TENG) and a Kelvin waterdrop generator is introduced, significantly improving the charge density and instantaneous power of WD-TENG. Experimental results show that the charge density and instantaneous power of a single waterdrop are much higher than previous records, capable of lighting up a large number of LEDs.
Article
Energy & Fuels
H. Ben Sassi, C. Alaoui, F. Errahimi, N. Es-Sbai
Summary: This paper investigates the suitability of V2G technology for the Moroccan national grid, outlining the state of art of the technology and the current status of the country's power grid. The paper also takes into consideration the evolution of the EV market in the country and the deployed EV charging infrastructure. Additionally, a survey on the potential services that V2G could provide is presented.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Physics, Multidisciplinary
Qiwei Yu, Dongliang Zhang, Yuhai Tu
Summary: This study reveals that the energy dissipation rate in a nonequilibrium reaction system has an inverse power-law dependence on the number of microscopic states in a coarse-grained state, and requires self-similarity of the underlying network. The scaling exponent of the dissipation law depends on the network structure and the probability flux correlation. The existence of the inverse dissipation scaling law is demonstrated in realistic biochemical systems such as biochemical oscillators and microtubule-kinesin active flow systems.
PHYSICAL REVIEW LETTERS
(2021)
Review
Computer Science, Information Systems
Seyed Mohammad Hosseini, Mehdi Soleymani, Sousso Kelouwani, Ali Akrem Amamou
Summary: This review article examines the crucial role of energy harvesting and recovery in the design of limited onboard power sources of battery electric vehicles (BEVs) and fuel cell hybrid electric vehicles (FCHEVs). The article studies various energy recovery and harvesting methods, investigates the impact of energy storage system and powertrain architecture on energy harvesting, reviews control strategies for regenerative braking, and discusses the potential of energy harvesting in electric vehicles. It also highlights the importance of perception and navigation technologies in autonomous vehicles to enhance energy efficiency and identifies research gaps and future directions in this field.
Article
Energy & Fuels
Odin Foldvik Eikeland, Colin C. Kelsall, Kyle Buznitsky, Shomik Verma, Filippo Maria Bianchi, Matteo Chiesa, Asegun Henry
Summary: As variable renewable energy sources increase, energy storage technologies are crucial for balancing energy generation and demand. This study models a real-world electricity system instead of hypothetical models, and focuses on an existing thermal energy storage concept with low capital cost for large-scale deployment. The results show that power availability increases with larger storage size, especially in scenarios with reduced CO2 emissions.
Article
Green & Sustainable Science & Technology
Wen-Kai Zhu, Cheng-yuan Wang, Li-song Wang, Xiao-han Wu, Qiang Yue
Summary: The power industry is crucial for achieving carbon emission peak and carbon neutrality. China's power industry is expected to undergo deep decarbonization and enhanced energy efficiency in the next 40 years, with a transition towards renewable energy generation and higher parameter thermal power plants. The study predicts significant environmental benefits from these adjustments, such as reduced CO2 emissions and savings in coal consumption, while promoting the development of wind and photovoltaic power generation.
SUSTAINABLE PRODUCTION AND CONSUMPTION
(2022)
Editorial Material
Multidisciplinary Sciences
Aaswath P. Raman
Editorial Material
Chemistry, Physical
Jyotirmoy Mandal, Yuan Yang, Nanfang Yu, Aaswath P. Raman
Article
Physics, Applied
Bin Zhao, Gang Pei, Aaswath P. Raman
APPLIED PHYSICS LETTERS
(2020)
Article
Nanoscience & Nanotechnology
Christopher Yeung, Ju-Ming Tsai, Brian King, Benjamin Pham, David Ho, Julia Liang, Mark W. Knight, Aaswath P. Raman
Summary: Complex nanophotonic structures can be efficiently designed using deep learning models to explore structure-property relationships and generate a wide range of complex designs. This approach overcomes the challenges of vast design possibilities in a high-dimensional design space, demonstrating the feasibility of using deep neural networks for inverse design of nanophotonic structures.
Article
Multidisciplinary Sciences
Jin Xu, Jyotirmoy Mandal, Aaswath P. Raman
Summary: Gradient ENZ materials enable broad-spectrum directional control of thermal emission, confining emitted thermal radiation to fixed narrow angular ranges. This broadband directional emission improves performance for applications such as thermal camouflaging, solar heating, radiative cooling, and waste heat recovery.
Article
Materials Science, Multidisciplinary
Christopher Yeung, Ryan Tsai, Benjamin Pham, Brian King, Yusaku Kawagoe, David Ho, Julia Liang, Mark W. Knight, Aaswath P. Raman
Summary: This study presents a global deep learning-based inverse design framework for optimizing photonic metasurfaces by training a neural network on images encoded with material and structural parameters. The network can identify effective metasurface designs based on target absorption spectra and generate multiple design variants with nearly identical absorption spectra.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Jin Xu, Aaswath P. Raman
Summary: Heating and cooling systems in buildings play a significant role in global energy use. By dynamically tuning the thermal emissivity of interior building surfaces, large energy savings can be achieved, both in cold and warm weather conditions.
Article
Chemistry, Multidisciplinary
John Brewer, Matthew F. Campbell, Pawan Kumar, Sachin Kulkarni, Deep Jariwala, Igor Bargatin, Aaswath P. Raman
Summary: This research demonstrates the characteristics of nanophotonic photonic crystal slab reflectors and explores new possibilities for simultaneously controlling optical and thermal response in ultralight nanophotonic structures. The findings provide important insights into the significance of thermal management in lightsail design.
Article
Chemistry, Multidisciplinary
Matthew F. Campbell, John Brewer, Deep Jariwala, Aaswath P. Raman, Igor Bargatin
Summary: The study suggests that light sails with nanometer-scale thicknesses accelerated to relativistic velocities by lasers need to be significantly curved to reduce mechanical stresses and avoid tears. It shows that a circular light sail's diameter and radius of curvature should be comparable in magnitude in optimal designs for gram-scale payloads, and that sail acceleration length decreases with increasing curvature when sufficient laser power is available. These findings offer critical guidance for future light sail design programs aimed at interstellar space exploration.
Article
Nanoscience & Nanotechnology
Christopher Yeung, David Ho, Benjamin Pham, Katherine T. Fountaine, Zihan Zhang, Kara Levy, Aaswath P. Raman
Summary: A fundamental challenge in the design of photonic devices is optimizing their overall architecture to achieve desired responses. Topology or shape optimizers based on the adjoint variable method are commonly used for their computational efficiency and ability to create complex freeform geometries. However, the functional understanding of such freeform structures remains unknown. Additionally, unless a design space of high-performance devices is known in advance, gradient-based optimizers can get stuck in local minima or saddle points, limiting the achievable performance. To address these issues, an inverse design framework combining adjoint optimization, automated machine learning, and explainable artificial intelligence is proposed. By integrating numerical electromagnetic simulation, this framework reveals structural contributions and uses explanation-based reoptimization to overcome local minima and further minimize the figure-of-merit (FOM). The framework is demonstrated in the context of waveguide splitter design and achieves significant increases in device performance compared to state-of-the-art adjoint optimization-based inverse design. These results showcase the potential of machine learning strategies to enhance conventional optimization-based inverse design algorithms while providing deeper insights into the designs.
Article
Nanoscience & Nanotechnology
Christopher Yeung, Benjamin Pham, Ryan Tsai, Katherine T. Fountaine, Aaswath P. Raman
Summary: In recent years, hybrid design strategies combining machine learning with electromagnetic optimization algorithms have been used for the inverse design of photonic structures and devices. These methods can rapidly identify optimal solutions and reduce computational costs. However, there is a need to optimize across both materials and geometries in a single integrated environment.
Article
Chemistry, Physical
Xin Huang, Jyotirmoy Mandal, Jin Xu, Aaswath P. Raman
Summary: As water scarcity becomes more serious due to climate change, there is increasing interest in finding low-carbon ways to generate fresh water from saline sources. Conventional desalination techniques require large energy inputs, while solar desalination is limited by seasonal and geographical factors. In this study, a passive cooling method that uses outer space as the ultimate heat sink is proposed and demonstrated to freeze and desalinate salt water.
Article
Physics, Applied
Xin Huang, Christopher Yeung, Aaswath P. Raman
Summary: A temporal coupled-mode theory for thermal emission from multiple, arbitrarily coupled resonators has been developed, and its accuracy has been validated through numerical simulations. The anomalous thermal emission spectra that can occur when multiple resonators with varying coupling strengths are coupled to each other have been highlighted.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Multidisciplinary
Jae S. Hwang, Jin Xu, Aaswath P. Raman
Summary: Researchers have designed and experimentally demonstrated an approach using doped III-V semiconductors to simultaneously control the spectral peak, bandwidth, and directionality of infrared emissivity. InAs-based gradient epsilon-near-zero (ENZ) photonic structures exhibit broadband directional emission with different spectral bandwidths and ranges depending on doping concentration profile and thickness. This approach provides a versatile photonic platform for dynamically controlling broadband spectral and directional emissivity in applications such as heat transfer and infrared sensing.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Aaswath P. Raman, Wei Li, Shanhui Fan
