Non-resonant Energy Research Articles

On the nonlinear energy interactions in vibro-impacting cantilever

The nonlinear energy interactions are an intriguing aspect of nonlinear oscillators, such as vibro-impacting cantilevers (VICs). Despite extensive research, the domain of energy interactions in nonlinear oscillators still requires further exploration. The motivation arises from the complex and captivating dynamics as well as the vast array of potential applications. This paper presents a comprehensive investigation of various energy interaction mechanisms within the resonance realms of the first and second mode resonance frequencies of harmonically base-excited VICs. These energy interactions are of paramount importance as they give rise to the captivating response of the VIC, characterized by multi- and quasi-periodicity, energy amplification, combination resonances, amplitude modulation, and other intriguing features. This paper introduces the phenomenon termed “Harmonic Resonance Energy Stimulation (HRES)” and extensively investigates its role in generating the secondary jump in the frequency response. Moreover, the present study discovers and reports the non-resonant energy interactions and resulting modulating, quasi-periodic response in the VIC. Various illustrative plots obtained from the theoretical investigation, relying on the mathematical model, have been utilized to facilitate a comprehensive investigation. The results hold immense significance as they contribute valuable knowledge to the nonlinear dynamics of VIC, which is of great importance in research advancements and practical applications.

Analytic forms of thermonuclear functions

In nuclear fusion reactions taking place in stellar interiors, if there is a deviation from hydrostatic equilibrium, then one can think of an alternative velocity distribution instead of the Maxwell–Boltzmann distribution. The paper is devoted to study the extension of non-resonant reaction rate integrals in standard, cut-off, depleted, and screened cases via Mittag-Leffler distribution. The extended non-resonant reaction rate integrals are represented in the form of Fox’s H-function, generalized Wright function. A comparison of the Mittag-Leffler non-resonant energy distributions with the standard Maxwell–Boltzmann energy distribution and the pathway energy distribution is also done.

The applicability study and validation of TULIP code for full energy range spectrum

NECP-SARAX is a neutronics analysis code system for advanced reactor developed by Nuclear Engineering Computational Physics Laboratory of Xi'an Jiaotong University. In past few years, improvements have been implemented in TULIP code which is the cross-section generation module of NECP-SARAX, including the treatment of resonance interface, considering the self-shielding effect in non-resonance energy range, hyperfine group method and nuclear library with thermal scattering law. Previous studies show that NECP-SARAX has high performance in both fast and thermal spectrum system analysis. The accuracy of TULIP code in fast and thermal spectrum system analysis is demonstrated preliminarily. However, a systematic verification and validation is still necessary. In order to validate the applicability of TULIP code for full energy range, 147 fast spectrum critical experiment benchmarks and 170 thermal spectrum critical experiment benchmarks were selected from ICSBEP and used for analysis. The keff bias between TULIP code and reference value is less than 300 pcm for all fast spectrum benchmarks. And that bias keeps within 200 pcm for thermal spectrum benchmarks with neutron-moderating materials such as polyethylene, beryllium oxide, etc. The numerical results indicate that TULIP code has good performance for the analysis of fast and thermal spectrum system.

Comment on: “Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave” [Phys. Plasmas 29, 022107 (2022)

Comment on: “Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave” [Phys. Plasmas <b>29</b>, 022107 (2022)

Response to comment on “Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave” [Phys. Plasmas 30, 084701 (2023)

This is a note in response to Dr. Machi's comment on our recent paper [S. M. Mahajan and F. A. Asenjo, Phys. Plasmas 29, 022107 (2022)].

Study of the Power Generation Performance of Impact Piezoelectric Energy Capture Devices.

In order to solve the problem of conventional energy shortages, a non-resonant impact piezoelectric energy capture device using a (polyvinylidene fluoride) piezoelectric film at low frequency is proposed, and related theoretical analysis and experimental studies are conducted. The device has a simple internal structure, is green and easy to miniaturize, and is capable of harvesting energy at low frequencies to supply energy to micro and small electronic devices. First, to verify the feasibility of the device, the structure of the experimental device is modeled and dynamically analyzed. Then the modal, stress-strain, and output voltage of the piezoelectric film are simulated and analyzed using COMSOL Multiphysics simulation software. Finally, the experimental prototype is built according to the model, and the experimental platform is constructed to test the relevant performance. The experimental results show that the output power produced by the capturer varies within a certain range when the capturer is excited externally. With an external excitation force of 30 N, a piezoelectric film bending amplitude of 60°, and a piezoelectric film size of 45 × 80 mm, the resulting output power voltage is 21.69 V, the output current is 0.07 mA, and the output power is 1.5176 mW. This experiment verifies the feasibility of the energy capturer and provides a new idea for powering electronic components.

Energy trapping in a phononic crystal cavity enhanced by nonreciprocal acoustic wave transmission

Defect mode induced energy trapping at the bandgap frequency of a phononic crystal has been widely explored. Unlike this extensively used mechanism, this work reports the use of nonreciprocity in the transmission band to trap energy inside a phononic crystal cavity. Passive nonreciprocity is due to natural viscosity of the background liquid (water) and asymmetry of aluminum scatterers. The level of non-resonant energy trapping was compared for three cavities with different symmetry. Enhancement of energy trapping at a frequency of 624 kHz was observed experimentally for the cavity where nonreciprocity suppresses acoustic radiation into environment. Experimental results were further investigated and confirmed using finite element numerical analysis.

A nonresonant triboelectric-electromagnetic energy harvester via a vibro-impact mechanism for low-frequency multi-directional excitations

A majority of current studies about non-resonant energy harvesters for low-frequency energy are based on pure experiment without theoretical modeling. In this work, a novel hybrid triboelectric-electromagnetic harvester in form of a rolling magnet inside a casing is proposed for scavenging low-frequency energy from multi-directional excitations, which includes a number of sub triboelectric energy harvesters (sub-TEHs) and two sub electromagnetic energy harvesters (sub-EEHs). Both the mechanical model and electrical model are established for a horizontal excitation, a rocking excitation and a vertical excitation. A velocity-dependent coefficient of restitution for impact and an impact-velocity-dependent charge density are obtained via experiment, which improve the theoretical model and result in better agreement between theoretical and experimental results. Structural response and electric outputs under different types of external excitations are investigated theoretically. It is found that the harvester has a good sensitivity to small-angle ultra-low-frequency rocking excitations, which is beneficial to low-frequency energy harvesting. When tested on a shake table at 4 Hz, a sub-TEH and a sub-EEH can generate peak powers of 212.1 µW and 57.8 mW, respectively. An electronic clock is able to work continuously when powered by the harvester shaken by hand. The harvester is also tested inside a handbag carried by a walking human for biomechanical energy and on a floating structure for wave energy, which exhibits good performance. This work presents a novel design with a capability of harvesting low-frequency energy under different external excitations, which contributes to the development and applications of triboelectric and electromagnetic energy harvesting.

Novel insights on energy transfer processes in [Ce4+/Ce3+]-Er3+-doped tellurite glass

Previous works have been already reported on multiphonon-assisted non-resonant energy transfer in Ce3+-Er3+-doped tellurite glasses. However, it is not clear the mechanism of the radiative emission of Er3+ centered at 1530 nm. In this paper, we reported a better understanding of the mechanism of interactions between those two rare-earth ions via a systematic study. For that, we will explore the energy transitions between Ce4+/Ce3+ and Er3+ ions in a tungsten-tellurite glass to both emission (in the near infrared) and upconversion (in the visible) spectrum. Here, Ce4+ and Ce3+ were obtained in an Er3+-doped tellurite glasses via the addition of different concentrations of CeO2 as part of the composition of the samples. Emission spectrum, under a 980 nm excitation, giving rise to a series of interactions between Ce3+↔Er3+ resulting in: (i) a subtle increase of the Er3+ emission intensity in the near-infrared region for 0.1 mol% of CeO2, and then a decrease in the emission for higher CeO2 concentration in both cases without any significant increase in the bandwidth, and (ii) a decrease of the visible upconversion emission intensity with the addition of CeO2. Such interactions are achieved via a coupling yielding and energy transfer from both rare-earth ions.

Experimental Inter-Modal Targeted Energy Transfer in a cantilever beam undergoing Vibro-impacts

This work experimentally demonstrates inter-modal targeted energy transfer (IMTET) in a cantilever beam system with vibro-impacts. IMTET is known to achieve non-resonant rapid energy transfer from low-to-high frequency structural modes in mechanical systems. While previous works have computationally demonstrated the efficacy of IMTET, the theory and methodology supporting IMTET still lacks experimental verification. To address this task, an experiment is constructed whereby a steel beam is clamped at one end and excited at the other, and steel tips with clearances anchored to a host fixture serve as vibro-impacts (VIs) which induce non-resonant energy redistribution within the modal space of the beam. The system is modeled as an Euler–Bernoulli cantilever beam which is discretized by the finite element method, and the VI forces are simulated by a single-sided dissipative Hertzian contact model. The time-responses, modal dissipation ratios, and characteristic decay times measured in the experiment are compared to the computational models to confirm the validity of the theoretical predictions. It is found for both the experiment and computational model that the VIs transfer energy from low frequency structural modes to high frequency ones which, in turn, results in a substantial reduction in the characteristic decay time and thus confirms the efficacy of IMTET in practice. The diverse potential applications of IMTET in engineering practice are then emphasized.

An Investigation of the Resonant and Non-Resonant Angular Time Delay of e-C60 Elastic Scattering

Time delay in electron scattering depends on both the scattering angle θ and scattered electron energy E. A study on the angular time delay of e-C60 elastic scattering was carried out in the present work. We employed the annular square well (ASW) potential to simulate the C60 environment. The contribution from different partial waves to the total angular time delay profile was examined in detail. The investigation was performed for both resonant and non-resonant energies, and salient characteristics in the time delay profile for each case were studied.

Development and Wave Tank Demonstration of a Fully Controlled Permanent Magnet Drive for a Heaving Wave Energy Converter

One option for converting the energy in sea waves into renewable electricity is the development of floating wave energy converters coupled to electrical generators. For this to work, bespoke slow-speed electrical machines coupled to bidirectional power smoothing power electronic converters are required. This paper reports on the successful design and wave tank validation of an electric machine, power converter and fully controlled direct drive power take-off system coupled to two small scale heaving wave energy converters. The design, development and demonstration of linear generators and power converters is presented including some simulated and laboratory results. Demonstration of wave energy converters with pure electric drives, fully automated control, bidirectional power flow and active force management is almost unique and essential for future wave energy development. The results presented prove that direct-drive power take-off for wave energy devices is technically possible and can be used to implement an automated control system with bidirectional power flow in both resonant and non-resonant wave energy systems.

Adjustment of JEFF-3.3 data for U-235 and Pu-239 in the fast, non-resonant energy range

A stochastic technique based upon the Serpent code is used along with the JEFF-3.3 nuclear data library consistently including their covariance, to adjust fast, non-resonant ENDF-6 format data for U-235 and Pu-239, and this in conjunction with the Asymptotic Generalized Linear Least-Squares (AGLLS) assimilation methodology. The current investigations are focused on simple, well documented critical systems such as Godiva and Jezebel exhibiting much stronger sensitivities of the assimilated parameters to this nuclear data. Correspondingly, the assimilation database consists of effective multiplication factors along with ratios of fission reaction rates per atom for Pu-239 and U-235 which are spectral indices measured at core center.By not identifying the fission cross-section of U-235 with a standard, we find that this data set should be decreased between 2 keV and 2.2 MeV; in relative terms by maximum 5.9 % occurring in the energy range between 41 keV and 67 keV which is less than two standard deviations (σ) of 6.6 %, obtained from the covariance files of the JEFF-3.3 library. Whereas ν¯ needs to be increased by up to ∼ 0.3 %, corresponding to half a σ. Also to reduce is the elastic scattering P1 cross-section between 111 keV and 10 MeV with a stronger decrease amounting to 12.7 % in the range 2.2 MeV-3.7 MeV.For the capture cross-section, we find a decrease of maximum 3 % between 111 keV and 3.7 MeV, in which case the one-σ limit is about 10 %.For Pu-239, the results of the adjustment study also indicate a reduction of the elastic scattering P1 cross-section in the same energy range as for U-235, however by only 5.7 %. The fission and inelastic scattering cross-section changes are much smaller than 1 %; as opposed to U-235, ν¯ is to decrease, and this by less than 0.5 % corresponding to one σ. The additionally proposed fission spectrum change not exceeding the one-σ limit somewhat shifts the median emission energy to a lower value. Differently from U-235, the adjustment of the capture cross-section is an increase of maximum 1.8 % in the range 2.2 MeV-3.7 MeV, which is well below the one-σ limit of the JEFF-3.3 library.

Non-resonant energy transfer from Eu3+ to Yb3+ in C-type and B-type (Eu1-xYbx)2O3 nanocrystals

The structural and spectroscopic properties of (Eu1-xYbx)2O3 nanocrystals with cubic (C-type) and monoclinic (B-type) crystalline structures have been studied. NCs have been synthetized by the sol-gel Pechini method and characterized at room temperature by X-ray diffraction, transmission electron microscopy, diffuse reflectance, Raman spectroscopy and photoluminescence techniques. NIR emission from Yb3+ ions has been observed in both C- and B-type NCs upon excitation of Eu3+ ions at 532 nm, where Yb3+ ions do not absorb photons. This fact reveals that an efficient non-resonant energy transfer process from Eu3+ to Yb3+ takes place, allowing to obtain simultaneous visible and NIR emissions under visible excitation. The decay curves of the 5D0 → 7F2 Eu3+ emission of C-type NCs corroborate this phenomenon since the Eu3+ lifetime has been found to decrease as the Yb3+ content increases. Finally, we discuss the use of the Eu3+ luminescence as a structural probe to distinguish between different RE2O3 polymorphs.

Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave

Dynamics of electrons subjected to a constant amplitude classical electromagnetic (EM) wave is investigated as a fundamental, representative problem in the physics of interacting quantum and classical waves. In the nonrelativistic regime (electrons as Schrödinger waves), the electron energy acquires a constant and a time dependent part. Driven by EM waves, both parts scale strongly with the amplitude, but we expect no resonant enhancement since the parallel electron “speed” of nonrelativistic electrons could never match the wave phase velocity. In the relativistic regime (electron as a Klein–Gordon wave), however, a class of electron waves (with parallel speed matching the EM phase speed) are resonantly excited to extremely high energies. Such a direct resonant energy transfer from intense electromagnetic waves constitutes a mechanism that could, in principle, power the most energetic of cosmic rays (this mechanism will work on protons just as well). Some predictions of the theory will, hopefully, be tested in laboratory laser experiments. The nonrelativistic calculations will also be examined in the context of recent experiments using photon-induced near-field electron microscopy in detail.

On the importance of antimony for temporal evolution of emission from self-assembled (InGa) (AsSb)/GaAs quantum dots on GaP(001)

Understanding the carrier dynamics of nanostructures is the key for development and optimization of novel semiconductor nano-devices. Here, we study the optical properties and carrier dynamics of (InGa)(AsSb)/GaAs/GaP quantum dots (QDs) by means of non-resonant energy and time-resolved photoluminescence depending on temperature. Studying this material system is fundamental in view of the ongoing implementation of such QDs for nano memory devices. The structures studied in this work include a single QD layer, QDs overgrown by a GaSb capping layer, and solely a GaAs quantum well, respectively. Theoretical analytical models allow to discern the common spectral features around the emission energy of 1.8 eV related to the GaAs quantum well and the GaP substrate. We observe type-I emission from QDs with recombination times between 2 ns and 10 ns, increasing towards lower energies. Moreover, based on the considerable tunability of the QDs depending on Sb incorporation, we suggest their utilization as quantum photonic sources embedded in complementary metal-oxide-semiconductor platforms, due to the feasibility of a nearly defect-free growth of GaP on Si. Finally, our analysis confirms the nature of the pumping power blue-shift of emission originating from the charged-background induced changes of the wavefunction spatial distribution.

Effective multi-group cross section calculation method for FCM fuel based on improved disadvantage factor method

Fully Ceramic Micro-encapsulated (FCM) fuel is an important candidate for the accident tolerant fuel (ATF). Compared with traditional fuel, the double heterogeneity of FCM fuel makes the effective multi-group cross section calculation more challenging. In this paper, an improved disadvantage factor method is proposed to deal with the self-shielding effect of FCM fuel in the resonance energy range and non-resonance energy range, to achieve the equivalent homogenization of the FCM fuel. A new equivalent particle–matrix model was constructed by using the particle Dancoff factor to overcome the problem that the traditional volume-weight equivalent model could not consider the macro heterogeneity between fuel rods. Based on the new one-dimensional equivalent sphere model, the ultrafine group slowing down equation is solved to obtain the ultrafine group disadvantage factor in the resonance energy region. In the non-resonance energy region, the multi-group disadvantage factors of the fast group and thermal group are obtained by using the eigenvalue calculation in the new equivalent particle–matrix model. The proposed method has been implemented in the high fidelity neutronics program NECP-X and tested with a set of cases. The results show its good agreement with the Monte Carlo reference for both the reactivity and self-shielding cross sections.

Design and analysis of a non-resonant rotational electromagnetic harvester with alternating magnet sequence

This paper proposed a portable non-resonant rotational electromagnetic vibration energy harvester using magnetic spring to scavenge kinetic energy from low-frequency human motion. Lagrange equations were established to study the dynamic characteristics of the harvester. MATLAB/Simulink was adopted to analyze the output performance at different excitation frequencies. A prototype has been fabricated for experiment, and the measured results are compared with the theoretical analysis. The energy harvester could respond to diverse vibration excitation. When external excitation frequency is 6 Hz, the output voltage and power density of the electromagnetic energy harvester are 2.2 V and 0.024 W·mm−3 respectively. Four LEDs are alight when external excitation frequency is 5 Hz. It is indicated that the electromagnetic energy harvester based on the magnet spring can efficiently harvest low frequency vibration energy at low frequencies. This work made a significant step toward energy harvesting from human motions. It has potential applications in self-powered portable electronics.

Textured, lead-free piezoelectric ceramics with high figure of merit for energy harvesting

Piezoelectrics are key materials for energy conversion, for example in ultrasound transducers and energy harvesters. This work presents the synthesis and characterization of the lead-free piezoelectric composition (Li0.06(K0.52Na0.48)0.94)(Nb0.71Ta0.29)O3 doped with 0.25 mol% Mn (KNNLTM) as textured ceramics. Templated grain growth from NaNbO3 platelet templates aligned by tape casting was used to introduce texture, and after sintering for 14 h at 1100 °C this produced up to 84% (100)pc grain orientation. After high temperature poling, the textured samples exhibit reasonable piezoelectric response with d 33 values up to 171 pC N−1, and k t values of 0.35, which is 71% of the response obtained in a single crystal of the same composition. The low relative dielectric permittivity of the textured and high temperature-poled KNNLTM (ϵ 33 T/ϵ 0 down to 182) resulted in record-high piezoelectric voltage constants (g 33 up to 101 mV m N−1), higher than previously reported for lead-free piezoelectric ceramics, as well as very high figure of merit (d 33 g 33 up to 16 × 10−12 m3 J−1) for non-resonant energy harvesting in compression. These numbers make the textured KNNLTM materials of this work highly promising for use in thickness mode, non-resonant piezoelectric energy harvesters.

Direct Transition from Triplet Excitons to Hybrid Light-Matter States via Triplet-Triplet Annihilation.

Strong light–matter coupling generates hybrid states that inherit properties of both light and matter, effectively allowing the modification of the molecular potential energy landscape. This phenomenon opens up a plethora of options for manipulating the properties of molecules, with a broad range of applications in photochemistry and photophysics. In this article, we use strong light–matter coupling to transform an endothermic triplet–triplet annihilation process into an exothermic one. The resulting gradual on–off photon upconversion experiment demonstrates a direct conversion between molecular states and hybrid light–matter states. Our study provides a direct evidence that energy can relax from nonresonant low energy molecular states directly into hybrid light–matter states and lays the groundwork for tunable photon upconversion systems that modify molecular properties in situ by optical cavities rather than with chemical modifications.